TY - JOUR AB - Barrett's esophagus (BE) is the main known precursor condition of esophageal adenocarcinoma (EAC). BE is defined by the presence of metaplasia above the normal squamous columnar junction and has mainly been attributed to gastroesophageal reflux disease and chronic reflux esophagitis. Thus, the rising incidence of EAC in the Western world is probably mediated by chronic esophageal inflammation, secondary to gastroesophageal reflux disease in combination with environmental risk factors such as a Western diet and obesity. However, (at present) risk prediction tools and endoscopic surveillance have shown limited effectiveness. Chemoprevention as an adjunctive approach remains an attractive option to reduce the incidence of neoplastic disease. Here, we investigate the feasibility of chemopreventive approaches in BE and EAC via inhibition of inflammatory signaling in a transgenic mouse model of BE and EAC (L2-IL1B mice), with accelerated tumor formation on a high-fat diet (HFD). L2-IL1B mice were treated with the IL-1 receptor antagonist Anakinra and the nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin or Sulindac. Interleukin-1b antagonism reduced tumor progression in L2-IL1B mice with or without a HFD, whereas both NSAIDs were effective chemoprevention agents in the accelerated HFD-fed L2-IL1B mouse model. Sulindac treatment also resulted in a marked change in the immune profile of L2-IL1B mice. In summary, anti-inflammatory treatment of HFD-treated L2-IL1B mice acted protectively on disease progression. These results from a mouse model of BE support results from clinical trials that suggest that anti-inflammatory medication may be effective in the chemoprevention of EAC. AU - Baumeister, T.* AU - Ingermann, J.* AU - Marcazzan, S. AU - Fang, H.* AU - Oellinger, R.* AU - Rad, R.* AU - Engleitner, T.* AU - Kleigrewe, K.* AU - Anand, A.* AU - Strangmann, J.* AU - Schmid, R.M.* AU - Wang, T.C.* AU - Quante, M.* C1 - 62978 C2 - 51092 CY - Great Clarendon St, Oxford Ox2 6dp, England SP - 1068-1078 TI - Anti-inflammatory chemoprevention attenuates the phenotype in a mouse model of esophageal adenocarcinoma. JO - Carcinogenesis VL - 42 IS - 8 PB - Oxford Univ Press PY - 2021 SN - 0143-3334 ER - TY - JOUR AB - Beyond the nearly uniform presence of KRAS mutations, pancreatic cancer is increasingly recognized as a heterogeneous disease. Preclinical in vivo model systems exist, but with the advent of precision oncology, murine models with enhanced genetic flexibility are needed to functionally annotate genetic alterations found in the human malignancy. Here, we describe the generation of focal gene disruptions and large chromosomal deletions via inducible and pancreas-specific expression of Cas9 in adult mice. Experimental mice are derived on demand directly from genetically engineered embryonic stem cells, without the need for further intercrossing. To provide initial validation of our approach, we show that disruption of the E3 ubiquitin ligase Rnf43 accelerates Kras(G12D)-dependent tumourigenesis. Moreover, we demonstrate that this system can be used to rapidly interrogate the impact of complex cancer-associated alleles through the generation of a previously unstudied 1.2 megabase deletion surrounding the CDKN2A and CDKN2B tumour suppressors. Thus, our approach is capable of reproducibly generating biallelic and precise loss of large chromosomal fragments that, in conjunction with mutant Kras, leads to development of pancreatic ductal adenocarcinoma with full penetrance. AU - Mishra, A.* AU - Emamgholi, F.* AU - Erlangga, Z.* AU - Hartleben, B.* AU - Unger, K. AU - Wolff, K.* AU - Teichmann, U.* AU - Kessel, M.* AU - Woller, N.* AU - Kühnel, F.* AU - Dow, L.E.* AU - Manns, M.P.* AU - Vogel, A.* AU - Lowe, S.W.* AU - Saborowski, A.* AU - Saborowski, M.* C1 - 56640 C2 - 47126 CY - Great Clarendon St, Oxford Ox2 6dp, England SP - 334-344 TI - Generation of focal mutations and large genomic deletions in the pancreas using inducible in vivo genome editing. JO - Carcinogenesis VL - 41 IS - 3 PB - Oxford Univ Press PY - 2020 SN - 0143-3334 ER - TY - JOUR AB - KRAS mutations of lung adenocarcinoma (LADC) are associated with smoking but little is known on other exposure-oncogene associations. Hypothesizing that different inciting agents may cause different driver mutations, we aimed to identify distinct molecular pathways to LADC, applying two entirely different approaches. First, we examined clinicopathologic features and genomic signatures of environmental exposures in the large LADC Campbell data set. Second, we designed a molecular mechanistic risk model of LADC (M3LADC) that links environmental exposure to incidence risk by mathematically emulating the disease process. This model was applied to incidence data of Japanese atom-bomb survivors which contains information on radiation and smoking exposure. Grouping the clinical data by driver mutations revealed two main distinct molecular pathways to LADC: one unique to transmembrane receptor-mutant patients that displayed robust signatures of radiation exposure and one shared between submembrane transducer-mutant patients and patients with no evident driver mutation that carried the signature of smoking. Consistently, best fit of the incidence data was achieved with a M3LADC with two pathways: in one LADC risk increased with radiation exposure and in the other with cigarette consumption. We conclude there are two main molecular pathways to LADC associated with different environmental exposures. Future molecular measurements in lung cancer tissue of atom-bomb survivors may allow to further test quantitatively the M3LADC-predicted link of radiation to transmembrane receptor mutations. Moreover, the developed molecular mechanistic model showed that for low doses, as relevant e.g. for medical imaging, smokers have the same radiation risk compared with never smokers. AU - Castelletti, N. AU - Kaiser, J.C. AU - Simonetto, C. AU - Furukawa, K.* AU - Küchenhoff, H.* AU - Stathopoulos, G.T. C1 - 55756 C2 - 46539 SP - 1240-1250 TI - Risk of lung adenocarcinoma from smoking and radiation arises in distinct molecular pathways. JO - Carcinogenesis VL - 40 IS - 10 PY - 2019 SN - 0143-3334 ER - TY - JOUR AB - Increased expression of osteopontin (secreted phosphoprotein 1, SPP1) is associated with aggressive human lung adenocarcinoma (LADC), but its function remains unknown. Our aim was to determine the role of SPP1 in smoking-induced LADC. We combined mouse models of tobacco carcinogen-induced LADC, of deficiency of endogenous Spp1 alleles, and of adoptive pulmonary macrophage reconstitution to map the expression of SPP1 and its receptors and determine its impact during carcinogenesis. Co-expression of Spp1 and mutant Kras(G12C) in benign cells was employed to investigate SPP1/KRAS interactions in oncogenesis. Finally, intratracheal adenovirus encoding Cre recombinase was delivered to LSL.KRAS(G12D) mice lacking endogenous or overexpressing transgenic Spp1 alleles. SPP1 was overexpressed in experimental and human LADC and portended poor survival. In response to two different smoke carcinogens, Spp1-deficient mice developed fewer and smaller LADC with decreased cellular survival and angiogenesis. Both lung epithelial- and macrophage-secreted SPP1 drove tumor-associated inflammation, while epithelial SPP1 promoted early tumorigenesis by fostering the survival of KRAS-mutated cells. Finally, loss and overexpression of Spp1 was, respectively, protective and deleterious for mice harboring KRAS(G12D)-driven LADC. Our data support that SPP1 is functionally involved in early stages of airway epithelial carcinogenesis driven by smoking and mutant KRAS and may present an important therapeutic target. AU - Giopanou, I.* AU - Kanellakis, N.I.* AU - Giannou, A.D.* AU - Lilis, I.* AU - Marazioti, A.* AU - Spella, M.* AU - Papaleonidopoulos, V.* AU - Simoes, D.C.M.* AU - Zazara, D.E.* AU - Agalioti, T.* AU - Moschos, C.* AU - Magkouta, S.* AU - Kalomenidis, I.* AU - Panoutsakopoulou, V.* AU - Lamort, A.-S. AU - Stathopoulos, G.T. C1 - 57365 C2 - 47768 CY - Great Clarendon St, Oxford Ox2 6dp, England SP - 1134-1144 TI - Osteopontin drives KRAS-mutant lung adenocarcinoma. JO - Carcinogenesis VL - 41 IS - 8 PB - Oxford Univ Press PY - 2019 SN - 0143-3334 ER - TY - JOUR AB - Lung adenocarcinoma (LADC) is the leading cause of cancer death worldwide. Nevertheless, syngeneic mouse models of the disease are sparse, and cell lines suitable for transplantable and immunocompetent mouse models of LADC remain unmet needs. We established multiple mouse LADC cell lines by repeatedly exposing two mouse strains (FVB, Balb/c) to the tobacco carcinogens urethane or diethylnitrosamine and by culturing out the resulting lung tumours for prolonged periods of time. Characterization of the resulting cell lines (n = 7) showed that they were immortal and phenotypically stable in vitro, and oncogenic, metastatic and lethal in vivo. The primary tumours that gave rise to the cell lines, as well as secondary tumours generated by transplantation of the cell lines, displayed typical LADC features, such as glandular architecture and mucin and thyroid transcription factor 1 expression. Moreover, these cells exhibited marked molecular similarity with human smokers' LADC, including carcinogen-specific Kras point mutations (Kras(Q61R) in urethane- and Kras(Q61H) in diethylnitrosamine-triggered cell lines) and Trp53 deletions and displayed stemness features. Interestingly, all cell lines overexpressed proliferin, a murine prolactin orthologue, which functioned as a lung tumour promoter. Furthermore, prolactin was overexpressed and portended poor prognosis in human LADC. In conclusion, we report the first LADC cell lines derived from mice exposed to tobacco carcinogens. These cells closely resemble human LADC and provide a valuable tool for the functional investigation of the pathobiology of the disease. AU - Kanellakis, N.I.* AU - Giannou, A.D.* AU - Pepe, M. AU - Αgalioti, T.* AU - Zazara, D.E.* AU - Giopanou, I.* AU - Psallidas, I.* AU - Spella, M.* AU - Μarazioti, A.* AU - Arendt, K.A.M. AU - Lamort, A.-S. AU - Tsaniras, S.C.* AU - Taraviras, S.* AU - Papadaki, H.* AU - Lilis, I.* AU - Stathopoulos, G.T. C1 - 55611 C2 - 46496 CY - Great Clarendon St, Oxford Ox2 6dp, England SP - 1352-1362 TI - Tobacco chemical-induced mouse lung adenocarcinoma cell lines pin the prolactin orthologue proliferin as a lung tumour promoter. JO - Carcinogenesis VL - 40 IS - 11 PB - Oxford Univ Press PY - 2019 SN - 0143-3334 ER - TY - JOUR AB - Non-small cell lung cancer is the most common type of lung cancer. Both environmental and genetic risk factors contribute to lung carcinogenesis. We conducted a genome-wide interaction analysis between single nucleotide polymorphisms (SNPs) and smoking status (never-versus ever-smokers) in a European-descent population. We adopted a two-step analysis strategy in the discovery stage: we first conducted a case-only interaction analysis to assess the relationship between SNPs and smoking behavior using 13 336 non-small cell lung cancer cases. Candidate SNPs with P-value <0.001 were further analyzed using a standard case-control interaction analysis including 13 970 controls. The significant SNPs with P-value <3.5 x 10(-5) (correcting for multiple tests) from the case-control analysis in the discovery stage were further validated using an independent replication dataset comprising 5377 controls and 3054 non-small cell lung cancer cases. We further stratified the analysis by histological subtypes. Two novel SNPs, rs6441286 and rs17723637, were identified for overall lung cancer risk. The interaction odds ratio and meta-analysis P-value for these two SNPs were 1.24 with 6.96 x 10(-7) and 1.37 with 3.49 x 10(-7), respectively. In addition, interaction of smoking with rs4751674 was identified in squamous cell lung carcinoma with an odds ratio of 0.58 and P-value of 8.12 x 10(-7). This study is by far the largest genome-wide SNP-smoking interaction analysis reported for lung cancer. The three identified novel SNPs provide potential candidate biomarkers for lung cancer risk screening and intervention. The results from our study reinforce that gene-smoking interactions play important roles in the etiology of lung cancer and account for part of the missing heritability of this disease. AU - Li, Y.* AU - Xiao, X.* AU - Han, Y.* AU - Gorlova, O.* AU - Qian, D.C.* AU - Leighl, N.* AU - Johansen, J.S.* AU - Barnett, M.* AU - Chen, C.* AU - Goodman, G.* AU - Cox, A.* AU - Taylor, F.* AU - Woll, P.* AU - Wichmann, H.-E. AU - Manz, J. AU - Muley, T.* AU - Risch, A.* AU - Rosenberger, A.* AU - Arnold, S.M.* AU - Haura, E.B.* AU - Bolca, C.* AU - Holcatova, I.* AU - Janout, V.* AU - Kontic, M.* AU - Lissowska, J.* AU - Mukeria, A.* AU - Ognjanovic, S.* AU - Orlowski, T.M.* AU - Scelo, G.* AU - Swiatkowska, B.* AU - Zaridze, D.* AU - Bakke, P.* AU - Skaug, V.* AU - Zienolddiny, S.* AU - Duell, E.J.* AU - Butler, L.M.* AU - Houlston, R.* AU - Artigas, M.S.* AU - Grankvist, K.* AU - Johansson, M.* AU - Shepherd, F.A.* AU - Marcus, M.W.* AU - Brunnström, H.* AU - Manjer, J.* AU - Melander, O.* AU - Müller, D.C.* AU - Overvad, K.* AU - Trichopoulou, A.* AU - Tumino, R.* AU - Liu, G.* AU - Bojesen, S.E.* AU - Wu, X.* AU - Le Marchand, L.* AU - Albanes, D.* AU - Bickeböller, H.* AU - Aldrich, M.C.* AU - Bush, W.S.* AU - Tardón, A.* AU - Rennert, G.* AU - Teare, M.D.* AU - Field, J.K.* AU - Kiemeney, L.A.* AU - Lazarus, P.* AU - Haugen, A.* AU - Lam, S.* AU - Schabath, M.B.* AU - Andrew, A.S.* AU - Bertazzi, P.A.* AU - Pesatori, A.C.* AU - Christiani, D.C.* AU - Caporaso, N.* AU - McKay, J.D.* AU - Brennan, P.* AU - Hung, R.J.* AU - Amos, C.I.* C1 - 52180 C2 - 43825 CY - Oxford SP - 336-346 TI - Genome-wide interaction study of smoking behavior and non-small cell lung cancer risk in Caucasian population. JO - Carcinogenesis VL - 39 IS - 3 PB - Oxford Univ Press PY - 2018 SN - 0143-3334 ER - TY - JOUR AB - Cullin-RING ubiquitin ligases (CRLs) responsible for substrate specificity of ubiquitination and play a key role in cell-cycle control and DNA damage response. In this study, we assessed associations between 16,599 SNPs in 115 CRL genes and lung cancer risk by using summary data of six published genome-wide association studies (GWASs) of 12,160 cases and 16,838 cases of European ancestry. As a result, we identified three independent SNPs in DCAF4 (rs117781739, rs12587742 and rs2240980) associated with lung cancer risk (odds ratio = 0.91, 1.09 and 1.09, respectively; 95% confidence interval = 0.88-0.95, 1.05-1.14 and 1.05-1.13, respectively; and P = 3.99×10-6, 4.97×10-5 and 1.44×10-5, respectively) after multiple comparison correction by a false discovery rate <0.05. Since SNP rs12587742 is located within the promoter region and one CpG island of DCAF4, we further performed in silico functional analyses and found that the rs12587742 variant A allele was associated with an increased mRNA expression (P = 2.20x10-16, 1.79x10-13 and 0.001 in blood cells, normal lung tissues and tumor tissues of lung squamous carcinoma, respectively) and a decreased methylation status (P = 2.48x10-9 and 0.032 in adipose and lung tumor tissues, respectively). Moreover, evidence from differential expression analyses further supported oncogenic effect of DCAF4 on lung cancer, with higher mRNA levels in both lung squamous carcinoma and adenocarcinoma (P = 4.48x10-11 and 1.22x10-9, respectively) than in adjacent normal tissues. Taken together, our results suggest that rs12587742 is associated with increased lung cancer risk, possibly by up-regulating mRNA expression and decreasing methylation status of DCAF4. AU - Liu, H.* AU - Liu, Z.* AU - Wang, Y.* AU - Stinchcombe, T.E.* AU - Owzar, K.* AU - Han, Y.* AU - Hung, R.J.* AU - Brhane, Y.* AU - McLaughlin, J.* AU - Brennan, P.* AU - Bickeböller, H.* AU - Rosenberger, A.* AU - Houlston, R.S.* AU - Caporaso, N.* AU - Landi, M.T.* AU - Brüske, I. AU - Risch, A.* AU - Wu, X.* AU - Ye, Y.* AU - Christiani, D.C.* AU - Amos, C.I.* AU - Wei, Q.* C1 - 50899 C2 - 42878 CY - Oxford SP - 541-551 TI - Functional variants in DCAF4 associated with lung cancer risk in European populations. JO - Carcinogenesis VL - 38 IS - 5 PB - Oxford Univ Press PY - 2017 SN - 0143-3334 ER - TY - JOUR AB - Strong evidence for the statistical association between radiation exposure and disease has been produced for thyroid cancer by epidemiological studies after the Chernobyl accident. However limitations of the epidemiological approach in order to explore health risks especially at low doses of radiation appear obvious. Statistical fluctuations due to small case numbers dominate the uncertainty of risk estimates. Molecular radiation markers have been searched extensively to separate radiation- induced cancer cases from sporadic cases. The overexpression of the CLIP2 gene is the most promising of these markers. It was found in the majority of papillary thyroid cancers (PTCs) from young patients included in the Chernobyl tissue bank. Motivated by the CLIP2 findings we propose a mechanistic model which describes PTC development as a sequence of rate-limiting events in two distinct paths of CLIP2-associated and multi-stage carcinogenesis. It integrates molecular measurements of the dichotomous CLIP2 marker from 141 patients into the epidemiological risk analysis for about 13,000 subjects from the Ukrainian-American cohort which were exposed below age 19 yr and were put under enhanced medical surveillance since 1998. For the first time a radiation risk has been estimated solely from marker measurements. Cross checking with epidemiological estimates and model validation suggests that CLIP2 is a marker of high precision. CLIP2 leaves an imprint in the epidemiological incidence data which is typical for a driver gene. With the mechanistic model we explore the impact of radiation on the molecular landscape of PTC. The model constitutes a unique interface between molecular biology and radiation epidemiology. AU - Kaiser, J.C. AU - Meckbach, R.* AU - Eidemüller, M. AU - Selmansberger, M. AU - Unger, K. AU - Shpak, V.* AU - Blettner, M.* AU - Zitzelsberger, H. AU - Jacob, P.* C1 - 49716 C2 - 40893 CY - Oxford SP - 1152-1160 TI - Integration of a radiation biomarker into modelling of thyroid carcinogenesis and post-Chernobyl risk assessment. JO - Carcinogenesis VL - 37 IS - 12 PB - Oxford Univ Press PY - 2016 SN - 0143-3334 ER - TY - JOUR AB - Centrosome abnormalities are often observed in premalignant lesions and in situ tumors and have been associated with aneuploidy and tumor development. We investigated the associations of 9354 single-nucleotide polymorphisms (SNPs) in 106 centrosomal genes with lung cancer risk by first using the summary data from six published genome-wide association studies (GWASs) of the Transdisciplinary Research in Cancer of the Lung (TRICL) (12 160 cases and 16 838 controls) and then conducted in silico replication in two additional independent lung cancer GWASs of Harvard University (984 cases and 970 controls) and deCODE (1319 cases and 26 380 controls). A total of 44 significant SNPs with false discovery rate (FDR) ≤ 0.05 were mapped to one novel gene FGFR1OP and two previously reported genes (TUBB and BRCA2). After combined the results from TRICL with those from Harvard and deCODE, the most significant association (P combined = 8.032×10(-6)) was with rs151606 within FGFR1OP. The rs151606 T>G was associated with an increased risk of lung cancer [odds ratio (OR) = 1.10, 95% confidence interval (95% CI) = 1.05-1.14]. Another significant tagSNP rs12212247 T>C (P combined = 9.589×10(-6)) was associated with a decreased risk of lung cancer (OR = 0.93, 95% CI = 0.90-0.96). Further in silico functional analyzes revealed that rs151606 might affect transcriptional regulation and result in decreased FGFR1OP expression (P trend = 0.022). The findings shed some new light on the role of centrosome abnormalities in the susceptibility to lung carcinogenesis. AU - Kang, X.* AU - Liu, H.* AU - Onaitis, M.W.* AU - Liu, Z.* AU - Owzar, K.* AU - Han, Y.* AU - Su, L.* AU - Wei, Y.* AU - Hung, R.J.* AU - Brhane, Y.* AU - McLaughlin, J.* AU - Brennan, P.* AU - Bickeböller, H.* AU - Rosenberger, A.* AU - Houlston, R.S.* AU - Caporaso, N.* AU - Landi, M.T.* AU - Heinrich, J. AU - Risch, A.* AU - Wu, X.* AU - Ye, Y.* AU - Christiani, D.C.* AU - Amos, C.I.* AU - Wei, Q.* AU - Transdisciplinary Research in Cancer of the Lung (TRICL) Research Team (*) C1 - 47977 C2 - 39804 CY - Oxford SP - 280-289 TI - Polymorphisms of the centrosomal gene (FGFR1OP) and lung cancer risk: A meta-analysis of 14 463 cases and 44 188 controls. JO - Carcinogenesis VL - 37 IS - 3 PB - Oxford Univ Press PY - 2016 SN - 0143-3334 ER - TY - JOUR AB - Several single-nucleotide polymorphisms (SNPs) have been associated with papillary and follicular thyroid cancer (PTC and FTC, respectively) risk, but few have replicated. After analyzing 17525 tag SNPs in 1129 candidate genes, we found associations with PTC risk in SERPINA5, FTO, HEMGN (near FOXE1) and other genes. Here, we report results from a replication effort in a large independent PTC/FTC case-control study conducted in Germany. We evaluated the best tagging SNPs from our previous PTC study and additionally included SNPs in or near FOXE1 and NKX2-1 genes, known susceptibility loci for thyroid cancer. We genotyped 422 PTC and 130 FTC cases and 752 controls recruited from three German clinical centers. We used polytomous logistic regression to simultaneously estimate PTC and FTC associations for 79 SNPs based on log-additive models. We assessed effect modification by body mass index (BMI), gender and age for all SNPs, and selected SNP by SNP interactions. We confirmed associations with PTC and SNPs in FOXE1/HEMGN, SERPINA5 (rs2069974), FTO (rs8047395), EVPL (rs2071194), TICAM1 (rs8120) and SCARB1 (rs11057820) genes. We found associations with SNPs in FOXE1, SERPINA5, FTO, TICAM1 and HSPA6 and FTC. We found two significant interactions between FTO (rs8047395) and BMI (P = 0.0321) and between TICAM1 (rs8120) and FOXE1 (rs10984377) (P = 0.0006). Besides the known associations with FOXE1 SNPs, we confirmed additional PTC SNP associations reported previously. We also found several new associations with FTC risk and noteworthy interactions. We conclude that multiple variants and host factors might interact in complex ways to increase risk of PTC and FTC. AU - Sigurdson, A.J.* AU - Brenner, A.V.* AU - Roach, J.A.* AU - Goudeva, L.* AU - Müller, J.A.* AU - Nerlich, K.* AU - Reiners, C.* AU - Schwab, R.* AU - Pfeiffer, L. AU - Waldenberger, M. AU - Braganza, M.* AU - Xu, L.* AU - Sturgis, E.M.* AU - Yeager, M.* AU - Chanock, S.J.* AU - Pfeiffer, R.M.* AU - Abend, M.* AU - Port, M.* C1 - 48640 C2 - 41228 CY - Oxford SP - 677-684 TI - Selected single-nucleotide polymorphisms in FOXE1, SERPINA5, FTO, EVPL, TICAM1 and SCARB1 are associated with papillary and follicular thyroid cancer risk: Replication study in a German population. JO - Carcinogenesis VL - 37 IS - 7 PB - Oxford Univ Press PY - 2016 SN - 0143-3334 ER - TY - JOUR AB - We identify inherited genetic variants associated with telomere length that may also confer risk for childhood cancers. Analyses reveal that genetic predisposition to longer telomere length increased risk of neuroblastoma, and potentially risk of osteosarcoma and acute lymphoblastic leukemia.Aberrant telomere lengthening is an important feature of cancer cells in adults and children. In addition to somatic mutations, germline polymorphisms in telomere maintenance genes impact telomere length. Whether these telomere-associated polymorphisms affect risk of childhood malignancies remains largely unexplored. We collected genome-wide data from three groups with pediatric malignancies [neuroblastoma (N = 1516), acute lymphoblastic leukemia (ALL) (N = 958) and osteosarcoma (N = 660)] and three control populations (N = 6892). Using case-control comparisons, we analyzed eight single nucleotide polymorphisms (SNPs) in genes definitively associated with interindividual variation in leukocyte telomere length (LTL) in prior genome-wide association studies: ACYP2, TERC, NAF1, TERT, OBFC1, CTC1, ZNF208 and RTEL1. Six of these SNPs were associated (P < 0.05) with neuroblastoma risk, one with leukemia risk and one with osteosarcoma risk. The allele associated with longer LTL increased cancer risk for all these significantly associated SNPs. Using a weighted linear combination of the eight LTL-associated SNPs, we observed that neuroblastoma patients were predisposed to longer LTL than controls, with each standard deviation increase in genotypically estimated LTL associated with a 1.15-fold increased odds of neuroblastoma (95%CI = 1.09-1.22; P = 7.9x10(-7)). This effect was more pronounced in adolescent-onset neuroblastoma patients (OR = 1.46; 95%CI = 1.03-2.08). A one standard deviation increase in genotypically estimated LTL was more weakly associated with osteosarcoma risk (OR = 1.10; 95%CI = 1.01-1.19; P = 0.017) and leukemia risk (OR = 1.07; 95%CI = 1.00-1.14; P = 0.044), specifically for leukemia patients who relapsed (OR = 1.19; 95%CI = 1.01-1.40; P = 0.043). These results indicate that genetic predisposition to longer LTL is a newly identified risk factor for neuroblastoma and potentially for other cancers of childhood. AU - Walsh, K.M.* AU - Whitehead, T.P.* AU - de Smith, A.J.* AU - Smirnov, I.V.* AU - Park, M.* AU - Endicott, A.A.* AU - Francis, S.S.* AU - Codd, V.* AU - ENGAGE Consortium Telomere Group (Albrecht, E. AU - Gieger, C. AU - Klopp, N. AU - Peters, A. AU - Wichmann, H.-E.) AU - Samani, N.J.* AU - Metayer, C.* AU - Wiemels, J.L.* C1 - 49018 C2 - 41567 CY - Oxford SP - 576-582 TI - Common genetic variants associated with telomere length confer risk for neuroblastoma and other childhood cancers. JO - Carcinogenesis VL - 37 IS - 6 PB - Oxford Univ Press PY - 2016 SN - 0143-3334 ER - TY - JOUR AB - Large-scale genome-wide association studies (GWAS) have likely uncovered all common variants at the GWAS significance level. Additional variants within the suggestive range (0.0001> P > 5×10(-8)) are, however, still of interest for identifying causal associations. This analysis aimed to apply novel variant prioritization approaches to identify additional lung cancer variants that may not reach the GWAS level. Effects were combined across studies with a total of 33456 controls and 6756 adenocarcinoma (AC; 13 studies), 5061 squamous cell carcinoma (SCC; 12 studies) and 2216 small cell lung cancer cases (9 studies). Based on prior information such as variant physical properties and functional significance, we applied stratified false discovery rates, hierarchical modeling and Bayesian false discovery probabilities for variant prioritization. We conducted a fine mapping analysis as validation of our methods by examining top-ranking novel variants in six independent populations with a total of 3128 cases and 2966 controls. Three novel loci in the suggestive range were identified based on our Bayesian framework analyses: KCNIP4 at 4p15.2 (rs6448050, P = 4.6×10(-7)) and MTMR2 at 11q21 (rs10501831, P = 3.1×10(-6)) with SCC, as well as GAREM at 18q12.1 (rs11662168, P = 3.4×10(-7)) with AC. Use of our prioritization methods validated two of the top three loci associated with SCC (P = 1.05×10(-4) for KCNIP4, represented by rs9799795) and AC (P = 2.16×10(-4) for GAREM, represented by rs3786309) in the independent fine mapping populations. This study highlights the utility of using prior functional data for sequence variants in prioritization analyses to search for robust signals in the suggestive range. AU - Brenner, D.R.* AU - Amos, C.I.* AU - Brhane, Y.* AU - Timofeeva, M.N.* AU - Caporaso, N.* AU - Wang, Y.* AU - Christiani, D.C.* AU - Bickeböller, H.* AU - Yang, P.* AU - Albanes, D.* AU - Stevens, V.L.* AU - Gapstur, S.M.* AU - Mckay, J.* AU - Boffetta, P.* AU - Zaridze, D.* AU - Szeszenia-Dabrowska, N.* AU - Lissowska, J.* AU - Rudnai, P.* AU - Fabianova, E.* AU - Mates, D.* AU - Bencko, V.* AU - Foretova, L.* AU - Janout, V.* AU - Krokan, H.E.* AU - Skorpen, F.* AU - Gabrielsen, M.E.* AU - Vatten, L.* AU - Njølstad, I.* AU - Chen, C.* AU - Goodman, G.* AU - Lathrop, M* AU - Vooder, T.* AU - Välk, K.* AU - Nelis, M.* AU - Metspalu, A.* AU - Broderick, P.* AU - Eisen, T.* AU - Wu, X.* AU - Zhang, D.* AU - Chen, W.* AU - Spitz, M.R.* AU - Wei, Y.* AU - Su, L.* AU - Xie, D.* AU - She, J.* AU - Matsuo, K.* AU - Matsuda, F.* AU - Ito, H.* AU - Risch, A.* AU - Heinrich, J. AU - Rosenberger, A.* AU - Muley, T.* AU - Dienemann, H.* AU - Field, J.K.* AU - Raji, O.* AU - Chen, Y.* AU - Gosney, J.* AU - Liloglou, T.* AU - Davies, M.P.* AU - Marcus, M.W.* AU - McLaughlin, J.* AU - Orlow, I.* AU - Han, Y.* AU - Li, Y.* AU - Zong, X.* AU - Johansson, M.* AU - Liu, G.* AU - Tworoger, S.S.* AU - Le Marchand, L.* AU - Henderson, B.E.* AU - Wilkens, L.R.* AU - Dai, J.C.* AU - Shen, H.* AU - Houlston, R.S.* AU - Landi, M.T.* AU - Brennan, P.* AU - Hung, R.J.* C1 - 46791 C2 - 37812 SP - 1314-1326 TI - Identification of lung cancer histology-specific variants applying Bayesian framework variant prioritization approaches within the TRICL and ILCCO consortia. JO - Carcinogenesis VL - 36 IS - 11 PY - 2015 SN - 0143-3334 ER - TY - JOUR AB - A previous study on papillary thyroid carcinomas (PTC) in young patients who were exposed to (131)Iodine from the Chernobyl fallout revealed an exclusive gain of chromosomal band 7q11.23 in exposed cases compared to an age-matched control cohort. CLIP2, a gene located within band 7q11.23 was shown to be differentially expressed between exposed and non-exposed cases at mRNA and protein level. Therefore, a standardized procedure for CLIP2 typing of PTCs has been developed in a follow-up study. Here we used CLIP2 typing data on 117 post-Chernobyl PTCs from two cohorts of exposed patients with individual dose estimates and 24 non-exposed controls to investigate a possible quantitative dose-response relationship of the CLIP2 marker. The "Genrisk-T" cohort consisted of 45 PTCs and the "UkrAm" cohort of 72 PTCs. Both cohorts differed in mean dose (0.59 Gy Genrisk-T, 1.2 Gy UkrAm) and mean age at exposure (2 years Genrisk-T, 8 years UkrAm), whilst the median latency (16 years Genrisk-T, 18 years UkrAm) was comparable. We analyzed the association between the binary CLIP2 typing and continuous thyroid dose with logistic regression. A clear positive dose-response relationship was found for young PTC cases (AaO < 20 years, AaE < 5 years). In the elder age group a higher proportion of sporadic tumors is assumed due to an increased frequency of CLIP2 negative cases, suggesting different molecular mechanisms in sporadic and radiation-induced cases. This is further supported by the association of elder patients (AaO > 20 years) with positivity for BRAF V600E mutation. AU - Selmansberger, M. AU - Kaiser, J.C. AU - Hess J. AU - Güthlin, D. AU - Likhtarov, I.* AU - Shpak, V.* AU - Tronko, M.* AU - Brenner, A.* AU - Abend, M.* AU - Blettner, M.* AU - Unger, K. AU - Jacob, P. AU - Zitzelsberger, H. C1 - 44811 C2 - 37063 CY - Oxford SP - 748-756 TI - Dose-dependent expression of CLIP2 in post-Chernobyl papillary thyroid carcinomas. JO - Carcinogenesis VL - 36 IS - 7 PB - Oxford Univ Press PY - 2015 SN - 0143-3334 ER - TY - JOUR AB - One of the major consequences of the 1986 Chernobyl reactor accident was a dramatic increase in papillary thyroid carcinoma (PTC) incidence, predominantly in patients exposed to the radioiodine fallout at young age. The present study is the first on genomic copy number alterations (CNAs) of PTCs of the Ukrainian American cohort (UkrAm) generated by Array Comparative Genomic Hybridization (aCGH). Unsupervised hierarchical clustering of CNA profiles revealed a significant enrichment of a subgroup of patients with female gender, long latency (> 17 years) and negative lymph node status. Further, we identified single CNAs that were significantly associated with latency, gender, radiation dose and BRAF status. Multivariate analysis revealed no interactions but additive effects of parameters gender, latency and dose on CNAs. The previously identified radiation-associated gain of the chromosomal bands 7q11.22-11.23 was present in 29% of cases. Moreover, comparison of our radiation-associated papillary thyroid carcinoma (PTC) data set with the TCGA data set on sporadic PTCs revealed altered copy numbers of the tumor driver genes NF2 and CHEK2. Further, we integrated the CNA data with transcriptomic data that were available on a subset of the herein analyzed cohort and did not find statistically significant associations between the two molecular layers. However, applying hierarchical clustering on a "BRAF-like/RAS-like" transcriptome signature split the cases into four groups, one of which containing all BRAF-positive cases validating the signature in an independent data set. AU - Selmansberger, M. AU - Braselmann, H. AU - Hess J. AU - Bogdanova, T.* AU - Abend, M.* AU - Tronko, M.* AU - Brenner, A.* AU - Zitzelsberger, H. AU - Unger, K. C1 - 46688 C2 - 37716 SP - 1381-1387 TI - Genomic copy number analysis of Chernobyl papillary thyroid carcinoma in the Ukrainian-American Cohort. JO - Carcinogenesis VL - 36 IS - 11 PY - 2015 SN - 0143-3334 ER - TY - JOUR AB - Selective removal of oncogenically transformed cells by apoptosis induced via signalling by surrounding cells has been suggested to represent a natural anticarcinogenic process. To investigate its potential effect in detail, a mechanistic model of this process is proposed. The model is calibrated against in vitro data on apoptosis triggered in transformed cells by defined external inducers as well as through signalling by normal cells under coculture conditions. The model predicts that intercellular induction of apoptosis is capable of balancing the proliferation of oncogenically transformed cells and limiting the size of their populations over long times, even if their proliferation per se were unlimited. Experimental research is desired to verify whether the predicted stable population of transformed cells corresponds to a kind of dormancy during early-stage carcinogenesis (dormant preneoplastic lesions), and how this process relates to other anticarcinogenic mechanisms taking place under in vivo conditions. AU - Kundrát, P. AU - Bauer, G.* AU - Jacob, P. AU - Friedland, W. C1 - 7162 C2 - 29502 SP - 253-259 TI - Mechanistic modelling suggests that the size of preneoplastic lesions is limited by intercellular induction of apoptosis in oncogenically transformed cells. JO - Carcinogenesis VL - 33 IS - 2 PB - Oxford Univ. Press PY - 2012 SN - 0143-3334 ER - TY - JOUR AB - Asthma has been hypothesized to be associated with lung cancer (LC) risk. We conducted a pooled analysis of 16 studies in the International Lung Cancer Consortium (ILCCO) to quantitatively assess this association and compared the results with 36 previously published studies. In total, information from 585 444 individuals was used. Study-specific measures were combined using random effects models. A meta-regression and subgroup meta-analyses were performed to identify sources of heterogeneity. The overall LC relative risk (RR) associated with asthma was 1.28 [95% confidence intervals (CIs) = 1.16-1.41] but with large heterogeneity (I(2) = 73%, P < 0.001) between studies. Among ILCCO studies, an increased risk was found for squamous cell (RR = 1.69, 95%, CI = 1.26-2.26) and for small-cell carcinoma (RR = 1.71, 95% CI = 0.99-2.95) but was weaker for adenocarcinoma (RR = 1.09, 95% CI = 0.88-1.36). The increased LC risk was strongest in the 2 years after asthma diagnosis (RR = 2.13, 95% CI = 1.09-4.17) but subjects diagnosed with asthma over 10 years prior had no or little increased LC risk (RR = 1.10, 95% CI = 0.94-1.30). Because the increased incidence of LC was chiefly observed in small cell and squamous cell lung carcinomas, primarily within 2 years of asthma diagnosis and because the association was weak among never smokers, we conclude that the association may not reflect a causal effect of asthma on the risk of LC. AU - Rosenberger, A.* AU - Bickeböller, H.* AU - McCormack, V.* AU - Brenner, D.R.* AU - Duell, E.J.* AU - Tjønneland, A.* AU - Friis, S.* AU - Muscat, J.E.* AU - Yang, P.* AU - Wichmann, H.-E. AU - Heinrich, J. AU - Szeszenia-Dabrowska, N.* AU - Lissowska, J.* AU - Zaridze, D.* AU - Rudnai, P.* AU - Fabianova, E.* AU - Janout, V.* AU - Bencko, V.* AU - Brennan, P.* AU - Mates, D.* AU - Schwartz, A.G.* AU - Cote, M.L.* AU - Zhang, Z.F.* AU - Morgenstern, H.* AU - Oh, S.S.* AU - Field, J.K.* AU - Raji, O.* AU - McLaughlin, J.R.* AU - Wiencke, J.* AU - LeMarchand, L.* AU - Neri, M.* AU - Bonassi, S.* AU - Andrew, A.S.* AU - Lan, Q.* AU - Hu, W.* AU - Orlow, I.* AU - Park, B.J.* AU - Boffetta, P.* AU - Hung, R.J.* C1 - 7264 C2 - 29624 SP - 587-597 TI - Asthma and lung cancer risk: A systematic investigation by the International Lung Cancer Consortium. JO - Carcinogenesis VL - 33 IS - 3 PB - Oxford Univ. Press PY - 2012 SN - 0143-3334 ER - TY - JOUR AB - RecQ helicase family members are involved in multiple DNA repair pathways, protecting the genome from incorrect recombination during mitosis and maintaining its stability. Deficiencies in genes encoding the RecQ helicases WRN and BLM lead to rare autosomal recessive diseases, Werner and Bloom syndromes, which have been implicated in early onset of aging, and predisposition to various types of cancer. We investigated associations of WRN, BLM and BLM-associated protein (BLAP75/RMI1) gene polymorphisms and risk of colorectal cancer (CRC), genotyping WRN V114I (rs2230009), WRN L1074F (rs2725362), WRN C1367R (rs1346044), RMI1 S455N (rs1982151) and BLM P868L (rs11852361). A large population-based case-control study, including 1795 CRC cases and 1805 controls, found no evidence for an association between the selected allelic variants in DNA repair-related genes and CRC risk. However, we detected a significant association of BLM P868L with an increased rectal cancer risk (odds ratio = 1.29, 95% confidence interval 1.02-1.64 and P = 0.04), suggesting a potential cancer-site specificity. This is the first study to analyze the associations between polymorphisms in WRN, BLM and RMI1 and CRC risk. Although none of them showed a significant association with CRC, the association of BLM P868L with rectal cancer risk requires further investigation. AU - Frank, B.* AU - Hoffmeister, M.* AU - Klopp, N. AU - Illig, T. AU - Chang-Claude, J.* AU - Brenner, H.* C1 - 1440 C2 - 27337 SP - 442-445 TI - Colorectal cancer and polymorphisms in DNA repair genes WRN, RMI1 and BLM. JO - Carcinogenesis VL - 31 IS - 3 PB - Oxford Univ. Press PY - 2010 SN - 0143-3334 ER - TY - JOUR AB - It is well known that approximately 90% of colorectal cancer (CRC) cases originate from the constitutive activation of the canonical Wnt signaling pathway. There is increasing evidence that genetic variation both in Wnt and apoptotic pathway genes affects CRC susceptibility and progression. This population-based case-control study, including 1795 CRC cases and 1805 controls, investigates the association between common, putative functional polymorphisms in DNFA5, HIF1A, NDRG1, PYGO1, SFRP2, SFRP4, WISP1 and WISP3 genes and CRC risk. We found no evidence for an association between the selected allelic variants and risk of CRC. Subsite analyses, however, revealed a significant association of HIF1A c.*191T>C with rectal cancer risk [odds ratio (OR) = 1.25, 95% confidence interval (CI), 1.03-1.51, P = 0.03] comparing minor allele carriers with major allele homozygotes. In addition, homozygosity for the minor allele of SFRP4 P320T was significantly associated with rectal cancer risk (OR = 1.37, 95% CI, 1.06-1.79, P = 0.02) and early-stage CRC (OR = 1.33, 95% CI, 1.05-1.69, P = 0.02). This study does not support the hypothesis that Wnt signaling- and apoptosis-related polymorphisms contribute to CRC risk. However, our results provide evidence that CRC subsets may be affected. If confirmed, this knowledge may be used to assess individual susceptibility and to target potential measures of cancer prevention. AU - Frank, B.* AU - Hoffmeister, M.* AU - Klopp, N. AU - Illig, T. AU - Chang-Claude, J.* AU - Brenner, H.* C1 - 4119 C2 - 27468 SP - 1381-1386 TI - Single nucleotide polymorphisms in Wnt signaling and cell death pathway genes and susceptibility to colorectal cancer. JO - Carcinogenesis VL - 31 IS - 8 PB - Oxford Univ. Press PY - 2010 SN - 0143-3334 ER - TY - JOUR AB - A recent study examined associations of tagging single nucleotide polymorphisms (tagSNPs) in 43 fatty acid metabolism-related genes and risk of colorectal cancer (CRC), showing rs8752, rs2612656 and a haplotype [comprising both of the single nucleotide polymorphisms (SNPs)] in the hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD) gene to be positively associated with CRC risk. In the present study, we attempted to replicate these single marker and haplotype associations, using 1795 CRC cases and 1805 controls from the German Darmkrebs: Chancen der Verhütung durch Screening study (DACHS). In addition to rs8752 and rs2612656, HPGD tagSNPs rs9312555, rs17360144 and rs7349744 were genotyped for haplotype analyses. Except for a marginally significant inverse association of HPGD rs8752 with CRC risk [odds ratio (OR) = 0.85; 95% confidence interval (CI) = 0.74, 0.98; P = 0.03], none of the analyzed tagSNPs showed any association with CRC. Subset analyses for colon and rectal cancers yielded similar, yet non-significant risk estimates at all five loci. Also, none of the haplotypes was found to be associated with CRC, colon or rectal cancers. However, rs8752 was significantly associated with a decreased risk of CRC among individuals with a body mass index < 30 (OR = 0.82, 95% CI = 0.70, 0.95, P = 0.01) as well as among smokers (OR = 0.74, 95% CI = 0.61, 0.90, P = 0.003). Yet, our data do not support the previously reported associations of HPGD tagSNPs and risk of CRC. AU - Frank, B.* AU - Hoeft, B.* AU - Hoffmeister, M.* AU - Linseisen, J. AU - Breitling, L.P.* AU - Chang-Claude, J.* AU - Brenner, H.* AU - Nieters, A. C1 - 4694 C2 - 28475 CY - Oxford, England SP - 190-196 TI - Association of hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD) variants and colorectal cancer risk. JO - Carcinogenesis VL - 32 IS - 2 PB - Oxford Univ. Press PY - 2010 SN - 0143-3334 ER - TY - JOUR AB - Colorectal cancer (CRC) is the third most common malignant tumor and the fourth leading cause of cancer death worldwide. The crucial role of fatty acids for a number of important biological processes suggests a more in-depth analysis of inter-individual differences in fatty acid metabolizing genes as contributing factor to colon carcinogenesis. We examined the association between genetic variability in 43 fatty acid metabolism-related genes and colorectal risk in 1225 CRC cases and 2032 controls participating in the European Prospective Investigation into Cancer and Nutrition study. Three hundred and ninety two single-nucleotide polymorphisms were selected using pairwise tagging with an r(2) cutoff of 0.8 and a minor allele frequency of >5%. Conditional logistic regression models were used to estimate odds ratios and corresponding 95% confidence intervals. Haplotype analysis was performed using a generalized linear model framework. On the genotype level, hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD), phospholipase A2 group VI (PLA2G6) and transient receptor potential vanilloid 3 were associated with higher risk for CRC, whereas prostaglandin E receptor 2 (PTGER2) was associated with lower CRC risk. A significant inverse association (P < 0.006) was found for PTGER2 GGG haplotype, whereas HPGD AGGAG and PLA2G3 CT haplotypes were significantly (P < 0.001 and P = 0.003, respectively) associated with higher risk of CRC. Based on these data, we present for the first time the association of HPGD variants with CRC risk. Our results support the key role of prostanoid signaling in colon carcinogenesis and suggest a relevance of genetic variation in fatty acid metabolism-related genes and CRC risk. AU - Hoeft, B.* AU - Linseisen, J. AU - Beckmann, L.* AU - Müller-Decker, K.* AU - Canzian, F.* AU - Hüsing, A.* AU - Kaaks, R.* AU - Vogel, U.* AU - Jakobsen, M.* AU - Overvad, K.* AU - Hansen, R.D.* AU - Knüppel, S.* AU - Boeing, H.* AU - Trichopoulou, A.* AU - Koumantaki, Y.* AU - Trichopoulos, D.* AU - Berrino, F.* AU - Palli, D.* AU - Panico, S.* AU - Tumino, R.* AU - Bueno-de-Mesquita, H.B.* AU - van Duijnhoven, F.J.* AU - van Gils, C.H.* AU - Peeters, P.H.* AU - Dumeaux, V.* AU - Lund, E.* AU - Huerta Castano, J.M.* AU - Muñoz, X.* AU - Rodriguez, L.* AU - Barricarte, A.* AU - Manjer, J.* AU - Jirstrom, K.* AU - van Guelpen, B.* AU - Hallmans, G.* AU - Spencer, E.A.* AU - Crowe, F.L.* AU - Khaw, K.-T.* AU - Wareham, N.J.* AU - Morois, S.* AU - Boutron-Ruault, M.-C.* AU - Clavel-Chapelon, F.* AU - Chajes, V.* AU - Jenab, M.* AU - Boffetta, P.* AU - Vineis, P.* AU - Mouw, T.* AU - Norat, T.* AU - Riboli, E.* AU - Nieters, A.* C1 - 2225 C2 - 27134 CY - Oxford, UK SP - 466-472 TI - Polymorphisms in fatty acid metabolism-related genes are associated with colorectal cancer risk. JO - Carcinogenesis VL - 31 IS - 3 PB - Oxford Univ. Press PY - 2010 SN - 0143-3334 ER - TY - JOUR AB - BACKGROUND: Analysis of candidate genes in individual studies has had only limited success in identifying particular gene variants that are conclusively associated with lung cancer risk. In the International Lung Cancer Consortium (ILCCO), we conducted a coordinated genotyping study of 10 common variants selected because of their prior evidence of an association with lung cancer. These variants belonged to candidate genes from different cancer-related pathways including inflammation (IL1B), folate metabolism (MTHFR), regulatory function (AKAP9 and CAMKK1), cell adhesion (SEZL6) and apoptosis (FAS, FASL, TP53, TP53BP1 and BAT3). METHODS: Genotype data from 15 ILCCO case-control studies were available for a total of 8431 lung cancer cases and 11 072 controls of European descent and Asian ethnic groups. Unconditional logistic regression was used to model the association between each variant and lung cancer risk. RESULTS: Only the association between a non-synonymous variant of TP53BP1 (rs560191) and lung cancer risk was significant (OR = 0.91, P = 0.002). This association was more striking for squamous cell carcinoma (OR = 0.86, P = 6 x 10(-4)). No heterogeneity by center, ethnicity, smoking status, age group or sex was observed. In order to confirm this association, we included results for this variant from a set of independent studies (9966 cases/11,722 controls) and we reported similar results. When combining all these studies together, we reported an overall OR = 0.93 (0.89-0.97) (P = 0.001). This association was significant only for squamous cell carcinoma [OR = 0.89 (0.85-0.95), P = 1 x 10(-4)]. CONCLUSION: This study suggests that rs560191 is associated to lung cancer risk and further highlights the value of consortia in replicating or refuting published genetic associations. AU - Truong, T.* AU - Sauter, W. AU - McKay, J.D.* AU - Hosgood, H.D.* AU - Gallagher, C.* AU - Amos, C.I.* AU - Spitz, M.* AU - Muscat, J.* AU - Lazarus, P.* AU - Illig, T. AU - Wichmann, H.-E. AU - Bickeböller, H.* AU - Risch, A.* AU - Dienemann, H.* AU - Zhang, Z.F.* AU - Naeim, B.P.* AU - Yang, P.* AU - Zienolddiny, S.* AU - Haugen, A.* AU - Le Marchand, L.* AU - Hong, Y.C.* AU - Kim, J.H.* AU - Duell, E.J.* AU - Andrew, A.S.* AU - Kiyohara, C.* AU - Shen, H.B.* AU - Matsuo, K.* AU - Suzuki, T.* AU - Seow, A.* AU - Ng, D.P.K.* AU - Lan, Q.* AU - Zaridze, D.* AU - Szeszenia-Dabrowska, N.* AU - Lissowska, J.* AU - Rudnai, P.* AU - Fabianova, E.* AU - Constantinescu, V.* AU - Bencko, V.* AU - Foretova, L.* AU - Janout, V.* AU - Caporaso, N.E.* AU - lbanes, D.* AU - Thun, M.* AU - Landi, M.T.* AU - Trubicka, J.* AU - Lener, M.* AU - Lubinski, J.* AU - EPIC-lung Consortium (*) AU - Wang, Y.* AU - Chabrier, A.* AU - Boffetta, P.* AU - Brennan, P.* AU - Hung, R.J.* C1 - 3238 C2 - 27303 SP - 625-633 TI - International Lung Cancer Consortium: Coordinated association study of 10 potential lung cancer susceptibility variants. JO - Carcinogenesis VL - 31 IS - 4 PB - Oxford Univ. Press PY - 2010 SN - 0143-3334 ER - TY - JOUR AB - NBS1 fulfills important functions for the maintenance of genomic stability and cellular survival. Mutations in the NBS1 (Nijmegen Breakage Syndrome 1) gene are responsible for the Nijmegen breakage syndrome (NBS) in humans. The symptoms of this disease and the phenotypes of NBS1-defective cells, especially their enhanced radiosensitivity, can be explained by an impaired DNA double-strand break-induced signaling and a disturbed repair of these DNA lesions. We now provide evidence that NBS1 is also important for cellular survival after oxidative or alkylating stress where it is required for the proper initiation of base excision repair (BER). NBS1 downregulated cells show reduced activation of poly-(adenosine diphosphate-ribose)-polymerase-1 (PARP1) following genotoxic treatment with H2O2 or methyl methanesulfonate, indicating impaired processing of damaged bases by BER as PARP1 activity is stimulated by the single-strand breaks intermediately generated during this repair pathway. Furthermore, extracts of these cells have a decreased capacity for the in vitro repair of a double-stranded oligonucleotide containing either uracil or 8-oxo-7,8-dihydroguanine to trigger BER. Our data presented here highlight for the first time a functional role for NBS1 in DNA maintenance by the BER pathway. AU - Sagan, D. AU - Müller, R. AU - Kröger, C. AU - Hematulin, A. AU - Mörtl, S. AU - Eckardt-Schupp, F. C1 - 575 C2 - 26251 SP - 408-415 TI - The DNA repair protein NBS1 influences the base excision repair pathway. JO - Carcinogenesis VL - 30 IS - 3 PB - Oxford Univ Press PY - 2009 SN - 0143-3334 ER - TY - JOUR AB - Cytochrome P450 (CYP) enzymes, involved in metabolism of tobacco carcinogens, are also involved in estrogen metabolism and many are regulated by estrogens. These genes may thus be of relevance to gender-specific differences in lung cancer risk, particularly in early-onset lung cancer, where a high proportion of women is observed. We conducted a case-control study to investigate genetic polymorphisms in cytochromes that might modify the risk of developing early-onset lung cancer. In total, 638 Caucasian patients under the age of 51 with primary lung cancer and 1300 cancer-free control individuals, matched by age and sex, were included in this analysis. Thirteen polymorphisms in the CYP1A1, CYP1B1, CYP2A13, CYP3A4 and CYP3A5 genes were analyzed. No significant association was found for any of the analyzed polymorphisms and lung cancer risk overall. However, among women, a significantly increased risk of early-onset lung cancer was observed for carriers of the minor allele of CYP1B1 SNP rs1056836 [odds ratio (OR) 1.97; 95% confidence interval (CI) 1.32-2.94; P < 0.001]. Also, a non-significant increase in lung cancer risk was observed in the group of women carriers of the minor allele of CYP2A13 SNP rs1709084 (OR 1.64; 95% CI 1.00-2.70; P = 0.05). The effect of these two polymorphisms was shown to be modified by smoking. Haplotype analysis was performed for CYP1B1 and CYP2A13. No differences between cases and controls were observed for both genes (P = 0.63 and P = 0.42 for CYP1B1 and CYP2A13, respectively). Our results suggest that the CYP1B1 and the CYP2A13 genotypes may contribute to individual susceptibility to early-onset lung cancer in women. AU - Timofeeva, M.N.* AU - Kropp, S.* AU - Sauter, W. AU - Beckmann, L.* AU - Rosenberger, A.* AU - Illig, T. AU - Jäger, B. AU - Mittelstraß, K. AU - Dienemann, H.* AU - Bartsch, H. AU - Bickeböller, H. AU - Chang-Claude, J.C. AU - Risch, A.* AU - Wichmann, H.-E. C1 - 1744 C2 - 26638 CY - England SP - 1161-1169 TI - CYP450 polymorphisms as risk factors for early-onset lung cancer: Gender-specific differences. JO - Carcinogenesis VL - 30 IS - 7 PB - Oxford Univ Press PY - 2009 SN - 0143-3334 ER - TY - JOUR AB - Genetic predisposition and environmental factors act in concert in the pathogenesis of multi-factorial diseases. Selenoproteins represent fundamental antioxidative systems for the maintenance of cellular redox homeostasis, which is altered in various disease processes. Optimal function of selenoproteins requires availability of sufficient amounts of the essential trace element selenium, but in many countries the nutritive selenium supply is regarded insufficient. Supplemental selenium has been shown to have cancer-protective effects in a variety of experimental settings and clinical studies. Pancreatic carcinoma has so far not been tested as an end-point in such studies. We thus investigated the influence of supplemental nutritive selenium on pancreatic carcinogenesis in selenium-deficient animals by use of a genetically defined disease model. Over a period of 800 days, all animals (n = 131) in the study developed tumours. Within this time, the mean total tumour latency was not influenced by the selenium status (471 versus 472 days). Also, the mean latency of pancreatic carcinomas (n = 83) was not influenced (464 versus 466 days). In contrast, the percentage of pancreatic tumors within all tumours was lower in the selenium-deficient group (55 versus 70%). A highly significant difference in the differentiation grade of the pancreatic tumours was evident between the two groups: selenium-deficient mice (n = 33) developed predominantly undifferentiated anaplastic carcinomas (26 anaplastic versus 7 differentiated), whereas in the selenium-supplemented group (n = 50) mainly well-differentiated carcinomas were detected (20 anaplastic versus 30 differentiated). These data point at a new role of the trace element selenium in carcinogenesis. AU - Aichler, M. AU - Algül, H.* AU - Behne, D.* AU - Hölzlwimmer, G. AU - Michalke, B. AU - Quintanilla-Martinez, L. AU - Schmidt, J. AU - Schmid, R.M. AU - Brielmeier, M. C1 - 755 C2 - 24641 SP - 2002-2007 TI - Selenium status alters tumour differentiation but not incidence or latency of pancreatic adenocarcinomas in Ela-TGF-alpha p53+/ mice. JO - Carcinogenesis VL - 28 IS - 9 PB - Oxford Univ. Press PY - 2007 SN - 0143-3334 ER - TY - JOUR AB - Colorectal cancer is the second leading cause of cancer deaths worldwide with diet playing a prominent role in disease initiation and progression. Flavonoids are secondary plant compounds that are suggested as protective ingredients of a diet rich in fruits and vegetables. We here tested whether flavone, a flavonoid that proved to be an effective apoptosis inducer in colon cancer cells in culture, can affect the development of aberrant crypt foci (ACFs) in C57BL/6J mice in vivo when preneoplastic lesions were induced by the carcinogen 1,2-dimethylhydrazine (DMH). Flavone applied at either a low dose (15 mg/kg body wt per day) or a high dose (400 mg/kg body wt per day) reduced the numbers of ACFs significantly, independent of whether it was supplied simultaneously with the carcinogen (blocking group) or subsequent to the tumor induction phase (suppressing group). Proteome analysis performed in colonic tissue samples revealed that flavone treatment increased the expression of a number of Krebs cycle enzymes in the suppressing group and this was associated with reduced crypt multiplicity. It suggests that mitochondrial substrate oxidation is increased by flavone in colonic cells in vivo as already observed in HT-29 cells in vitro as the prime mechanism underlying tumor cell apoptosis induction by flavone. In conclusion, flavone reduces the number of ACFs in DMH-treated mice at doses that can be achieved for flavonoids by a diet rich in fruits and vegetables. Moreover, reduction in crypt multiplicity by flavone is most probably due to the preservation of a normal oxidative metabolism. AU - Winkelmann, I.* AU - Diehl, D.* AU - Oesterle, D. AU - Daniel, H.* AU - Wenzel, U.* C1 - 1336 C2 - 25186 SP - 1446-1454 TI - The suppression of aberrant crypt multiplicity in colonic tissue of 1,2-dimethylhydrazine-treated C57BL/6J mice by dietary flavone is associated with an increased expression of Krebs cycle enzymes. JO - Carcinogenesis VL - 28 IS - 7 PB - Oxford Univ. Press PY - 2007 SN - 0143-3334 ER - TY - JOUR AB - We showed previously that CYP1B1-null mice developed 10 times less lymphomas than wild-type mice after receiving 7,12-dimethylbenz[a]anthracene (DMBA). In this study a 10-fold lower dose was applied to differentiate between toxicity induced lymphomas (200 μg/mouse/day) and tumor initiation (20 μg/day). DMBA adducts to DNA of organs of mice, or to DNA of V79 cells expressing single mice or human cytochrome P450 isoenzymes were also measured. Mice were dosed three cycles of 5 days/week with DMBA in corn oil orally. Histopathology was determined at intermittent death or 1 year after dosing. DMBA–DNA adducts were assayed by 32P-postlabeling. At 20 μg/day, wild-type mice developed ovary (71%, stromal cells derived), skin (36%), uterus (64%) and lung (14%) hyperplasias. At this dose the CYP1B1-null mice developed no lymphomas, 25% ovary (epithelial cells derived), 8% skin, 58% uterus and 33% lung tumors. Oil control mice (n = 35) developed only eight, mostly different, hyperplasias. Wild-type mice had more DMBA–DNA adducts than the CYP1B1-null mice. The differences were highest in thymus, spleen, ovaries and testes (5–7-fold). Additionally, one specific DMBA–DNA adduct was reduced in CYP1B1-null mice. V79-cells expressed mouse CYP1B1 was 35 times more active than mouse CYP1A1 in forming DMBA–DNA adducts. Human CYP1B1 was 2.5 times less active than mouse CYP1B1 but 2.3-fold more active than human CYP1A1. CYP1B1 is the dominant enzyme in metabolizing DMBA to carcinogenic metabolites at high and low doses in mice, leading to an increased tumor rate of especially the ovaries at low doses of DMBA. Wild-type mice had more DMBA–DNA adducts than CYP1B1-null mice. Additionally, a specific adduct was less present in the CYP1B1-null mice. Human CYP1B1 was less active than mouse CYP1B1, but more active than human CYP1A1 in forming DMBA–DNA adducts. Thus, we expect CYP1B1 to be an important DMBA activating enzyme in humans also. AU - Buters, J. AU - Quintanilla-Martinez, L. AU - Schober, W.* AU - Soballa, V.J.* AU - Hintermair, J. AU - Wolff, T. AU - Gonzalez, F.J.* AU - Greim, H.* C1 - 10303 C2 - 20881 SP - 327-334 TI - CYP1B1 determines susceptibility to low doses of 7,12-dimethylbenz[a]anthracene-induced ovarian cancers in mice : Correlation of CYP1B1-mediated DNA adducts with carcinogenicity. JO - Carcinogenesis VL - 24 IS - 2 PY - 2003 SN - 0143-3334 ER - TY - JOUR AB - In this study, we investigated whether tumor-associated E-cadherin mutations impair the tumor-suppressive function of the cell adhesion molecule and influence metastasis formation in a severe combined immunodeficiency mouse model. The investigated E-cadherin mutations were in frame deletions of exons 8 (del 8) or 9 (del 9) and a point mutation in exon 8 (p8). Transfected human MDA-MB-435S carcinoma cells stably expressing wild-type (wt) or mutant E-cadherin were injected into the mouse mammary fat pad. Mice transplanted with wt E-cadherin transfectants developed significantly smaller tumors than animals transplanted with the E-cadherin-negative parental cell line. Animals transplanted with del 9 or p8 E-cadherin transfectants produced medium size tumors, indicating that these mutations impair the tumor-suppressive function of E-cadherin. In contrast, mice transplanted with del 8 E-cadherin transfectants developed tumors of approximately the same sizes as animals transplanted with wt E-cadherin expressing cells. Lung metastases were induced by all cell lines without significant differences. Immunohistochemical analysis of E-cadherin expression in the tumors revealed a heterogeneous staining pattern, indicating loss or down-regulation of E-cadherin in some tumor cells. Metastases were completely negative for E-cadherin. Our data suggest that the type of mutation determines whether the tumor-suppressive function of E-cadherin is impaired. AU - Kremer, M. AU - Quintanilla-Martinez, L. AU - Fuchs, M.* AU - Gamboa-Dominguez, A.* AU - Haye, S.* AU - Kalthoff, H.* AU - Rosivatz, E.* AU - Hermannstädter, C.* AU - Busch, R.* AU - Höfler, H. AU - Luber, B.* C1 - 10306 C2 - 21400 SP - 1879-1886 TI - Influence of tumor-associated E-cadherin mutations on tumorgenicity and metastasis. JO - Carcinogenesis VL - 24 IS - 12 PY - 2003 SN - 0143-3334 ER - TY - JOUR AB - Propylene oxide (PO) is a high-volume chemical intermediate that causes a low incidence of nasal tumors in rodents exposed to high concentrations (≥300 p.p.m.). PO reacts with DNA forming mainly N7-(2-hydroxypropyl)guanine (7-HPG). The exposure-dependent accumulation of 7-HPG in nasal respiratory epithelium (NRE), lung and liver was determined in male F344 rats exposed to PO (0, 5, 25, 50, 300 or 500 p.p.m.) by the inhalation route for 3 or 20 days (6 h/day; 5 days/week). These exposures ranged from low concentrations, such as those potentially occurring in the workplace, to high concentrations that proved to be carcinogenic in rodents. Analysis of 7-HPG in DNA by gas chromatography–high-resolution mass spectrometry (GC–HRMS) showed a linear response in 7-HPG for all three tissues after 3 days of exposure, and for NRE and lung after 20 days of exposure. A slightly sublinear response in 7-HPG was observed in liver after 20 days of exposure. For both exposure periods, the NRE had the highest concentration of 7-HPG, followed by lung and liver. The amount of 7-HPG in NRE was seven and 17 times higher than in lung and liver, respectively, for the 3 day exposures. For the 20 day exposures, the concentration of 7-HPG in NRE was six and 13 times higher than that in lung and liver, respectively, over the concentration range studied. These results demonstrate a much higher extent of DNA alkylation in the target tissue for carcinogenesis, than in non-target tissues. As PO-induced tumor formation was highly sublinear, occurring only at high vapor concentrations, whereas 7-HPG adducts were shown to be linearly dependent on airborne concentration, these results suggest that 7-HPG is not sufficient for PO nasal carcinogenesis and that other factors such as increased cell proliferation may be important in determining the tumor exposure response. AU - Rios-Blanco, M.N.* AU - Ranasinghe, A.* AU - Lee, M.S. AU - Faller, T.H. AU - Filser, J.G. AU - Swenberg, J.A.* C1 - 10305 C2 - 21051 SP - 1233-1238 TI - Molecular dosimetry of N7-(2-hydroxypropyl)guanine in tissues of F344 rats after inhalation exposure to propylene oxide. JO - Carcinogenesis VL - 24 IS - 7 PY - 2003 SN - 0143-3334 ER - TY - JOUR AB - We have recently identified a locus exhibiting a high frequency of allelic imbalance (AI) in both spontaneous human (HSA 6q14.1-15) and radiogenic murine (MMU9, 42 cM) osteosarcoma. Here we describe the fine mapping of the locus in osteosarcoma arising in (BALB/c x CBA) F-1 hybrid mice. These studies have allowed us to identify Tbx18, a member of the T-box transcriptional regulator gene family, as a candidate gene. Three intragenic Tbx18 polymorphisms were used to map the region of maximum AI to within the gene itself; 16 of 17 tumours exhibited imbalances of at least one of these markers. The highest frequency was found in exon 1, where 14 of 17 tumours were affected at a single nucleotide polymorphism at 541 nt. Two polymorphic CA repeat markers in intron 2 and intron 5 demonstrated overlapping regions of imbalance in several tumours. Both markers flanking the Tbx18 gene (D90sm48 and D9Mit269) revealed significantly lower frequencies of imbalance and confirmed the limitation of the common interval to Tbx18. Examination of both the mouse and human annotated genomic sequences indicated Tbx18 to be the only gene within the interval. Sequence analysis of the Tbx18 coding region did not reveal any evidence of mutation. Given the haploinsufficiency phenotypes reported for other T-box genes, we speculate that AI may influence the function of Tbx18 during osteosarcomagenesis. AU - Rosemann, M. AU - Kuosaite, V.* AU - Nathrath, M. AU - Strom, T.M. AU - Quintanilla-Martinez, L. AU - Richter, T.* AU - Imai, K. AU - Atkinson, M.J. C1 - 10304 C2 - 20939 SP - 371-376 TI - Allelic imbalance at intragenic markers of Tbx18 is a hallmark of murine osteosarcoma. JO - Carcinogenesis VL - 24 IS - 3 PB - Oxford Univ. Press PY - 2003 SN - 0143-3334 ER - TY - JOUR AB - Inherited mutations of Patched (PTCH) in the nevoid basal cell carcinoma syndrome (NBCCS) lead to several developmental defects and contribute to tumor formation in a variety of tissues. PTCH mutations have been also identified in sporadic tumors associated with NBCCS including basal cell carcinoma (BCC) and medulloblastoma. Mice heterozygous for Ptch recapitulate the typical developmental symptoms of NBCCS and develop rhabdomyosarcoma (RMS) and medulloblastoma. PTCH is assumed to act as a tumor suppressor gene although inactivation of both alleles has been demonstrated only in a fraction of tumors. We have investigated the status of Ptch in RMS of heterozygous Ptch(neo67/+) mice. Although the wild-type Ptch allele was retained in tumor tissue, the high levels of Ptch mRNA in these tumors result from overexpression of the mutant Ptch transcript. Our results suggest that the wild-type Ptch allele might be selectively silenced in RMS tissue or, alternatively, that haploinsufficiency of Ptch is sufficient to promote RMS formation in mice. AU - Calzada-Wack, J. AU - Kappler, R. AU - Schnitzbauer, U. AU - Richter, T.* AU - Nathrath, M.* AU - Rosemann, M.* AU - Wagner, S.N.* AU - Hein, R.* AU - Hahn, H.* C1 - 10307 C2 - 20274 SP - 727-733 TI - Unbalanced overexpression of the mutant allele in murine Patched mutants. JO - Carcinogenesis VL - 23 IS - 5 PB - Oxford Univ. Press PY - 2002 SN - 0143-3334 ER - TY - JOUR AB - Glucosinolates (GL) can inhibit, retard or reverse experimental multistage carcinogenesis. When brassica plant tissue is broken, GLs are hydrolyzed by the endogenous enzyme myrosinase (Myr), releasing many products including isothiocyanates (ITC). Synthetic ITCs like sulforaphane exert chemopreventive effects against chemically induced tumors in animals, modulating enzymes required for carcinogens' activation/detoxification and/or the induction of cell-cycle arrest and apoptosis in tumor cell lines. To investigate the chemopreventive potential of ITCs while reproducing the circumstances of dietary contact with sulforaphane, we studied proliferation, apoptosis induction and p53, bcl-2 and bax protein expression in Jurkat T-leukemia cells by sulforaphane, the ITC generated in situ in a quantitative manner by Myr starting from glucoraphanin (GRA). Jurkat cells were treated with different doses of GRA-Myr mixture. Effects on cell growth or survival were evaluated by counting trypan blue-excluding cells. Cell-cycle progression, apoptosis and expression of p53, bax and bcl-2 proteins were analyzed by flow cytometry. Results were analyzed by two-sided Fisher's exact test. Sulforaphane, but not GRA, caused G(2)/M-phase arrest (P = 0.028) and increase of apoptotic cell fraction (P < 0.0001) in a time- and dose-dependent manner. Necrosis was observed after prolonged exposure to elevated sulforaphane doses. Moreover, it markedly increased p53 and bax protein expression, and slightly affected bcl-2 expression. These findings indicate that sulforaphane but not the native GL GRA can exert both protective and toxic effects inhibiting leukemic cell growth. Sulforaphane therefore deserves study as a potential chemopreventive/chemotherapeutic antileukemic agent. AU - Fimognari, C.* AU - Nüsse, M. AU - Cesari, R.* AU - Iori, R.* AU - Cantelli-Forti, G.* AU - Hrelia, P.* C1 - 10309 C2 - 20385 SP - 581-586 TI - Growth inhibition, cell-cycle arrest and apoptosis in human T-cell leukemia by the isothiocyanate sulforaphane. JO - Carcinogenesis VL - 23 IS - 4 PB - Oxford Univ. Press PY - 2002 SN - 0143-3334 ER - TY - JOUR AB - Lack of a chromatin structure and histone protection makes mitochondrial DNA susceptible to oxidative damage. Suboptimal DNA repair leads to a higher frequency of mitochondrial mutations, which are associated with aging, carcinogenesis and environmental insult. The instability of the hypervariable region 11 of the mitochondrial genome was investigated in radiation-associated thyroid tumours, which were diagnosed in children from Belarus after the accident at the Chernobyl nuclear power plant, and from 40 sporadic thyroid tumours from Munich. Two mutations were identified in two out of 126 tumours from Belarus, and eight mutations were found in six out of 40 tumours from Munich. All mutations were deletions or insertions of C in a poly-cytidine (C7TC6) microsatellite. The mutation frequency correlated with the age of the patients at surgery. Mutations with the typical pattern of base substitutions following oxidative DNA damage were not identified. AU - Lohrer, H.D.* AU - Hieber, L. AU - Zitzelsberger, H. C1 - 10308 C2 - 20369 SP - 1577-1587 TI - Differential mutation frequency in mitochondrial DNA from thyroid tumours. JO - Carcinogenesis VL - 23 IS - 10 PB - Oxford Univ. Press PY - 2002 SN - 0143-3334 ER - TY - JOUR AB - The industrial solvent 2-nitropropane (2-NP) is a genotoxic hepatocarcinogen in rats. The genotoxicity of the compound in rats has been attributed to sulfotransferase-mediated formation of DNA-reactive nitrenium ions from the anionic form of 2-NP, propane 2-nitronate (P2N). Whether human sulfotransferases are capable of activating P2N is unknown. In the present study we have addressed this question by investigating the genotoxicity of P2N in various V79-derived cell lines engineered for expression of individual forms of human sulfotransferases, the phenol-sulfating and the monoamine-sulfating phenol sulfotransferases (hP-PST and hM-PST) and the human hydroxysteroid sulfotransferase (hHST). Genotoxicity was assessed by measuring the induction of DNA repair synthesis and by analyzing the formation of DNA modifications. P2N induced repair synthesis in V79-hP-PST and V79-hM-PST cells, whereas induction of repair synthesis in V79-hHST cells was negligible. P2N also resulted in the formation of 8-aminodeoxyguanosine and increased the level of 8-oxodeoxyguanosine in V79-hP-PST cells, but not in the parental V79-MZ cells, which do not show any sulfotransferase activity. Acetone oxime, the tautomeric form of the first reduction product of 2-NP, 2-nitrosopropane, was inactive in all cell lines. The results show that the human phenol sulfotransferases P-PST and M-PST are capable of metabolically activating P2N (P-PST > M-PST) and that the underlying mechanism is apparently identical to that resulting in the activation of P2N in rat liver, where 2-NP causes carcinomas. These results support the notion that 2-NP should be regarded as a potential human carcinogen. AU - Kreis, P. AU - Brandner, S. AU - Coughtrie, M.W.* AU - Pabel, U.* AU - Meinl, W.* AU - Glatt, H.* AU - Andrae, U. C1 - 23957 C2 - 31412 SP - 295-299 TI - Human phenol sulfotransferases hP-PST and hM-PST activate propane 2-nitronate to a genotoxicant. JO - Carcinogenesis VL - 21 IS - 2 PB - Oxford Univ. Press PY - 2000 SN - 0143-3334 ER - TY - JOUR AB - Propylene oxide (PO) is a relatively weak mutagen that induces nasal tumor formation in rats during long-term inhalation studies at high exposures (≥300 p.p.m.), concentrations that also cause cytotoxicity and increases in cell proliferation. Direct alkylation of DNA by PO leads mainly to the formation of N7-(2-hydroxypropyl)guanine (7-HPG). In this study, the accumulation of 7-HPG in tissues of male F344 rats exposed to 500 p.p.m. PO (6 h/day, 5 days/week for 4 weeks) by the inhalation route was measured by gas chromatography–high resolution mass spectrometry (GC-HRMS). In animals killed up to 7 h following the end of the last exposure the levels of 7-HPG (pmol/μmol guanine) in nasal respiratory tissue, nasal olfactory tissue, lung, spleen, liver and testis DNA were 606.2 ± 53.0, 297.5 ± 56.5, 69.8 ± 3.8, 43.0 ± 3.8, 27.5 ± 2.4 and 14.2 ± 0.7, respectively. The amounts of 7-HPG in the same tissues of animals killed 3 days after cessation of exposure were 393.3 ± 57.0, 222.7 ± 29.5, 51.5 ± 1.2, 26.7 ± 1.0, 18.0 ± 2.6 and 10.4 ± 0.1. A comparable rate of disappearance of 7-HPG was found among all tissues. DNA from lymphocytes pooled from four rats killed at the end of the last exposure was found to have 39.6 pmol adduct/μmol guanine. Quantitation of DNA apurinic/apyrimidinic sites, potentially formed after adduct loss by chemical depurination or DNA repair, showed no difference between tissues from control and exposed rats. The level of N-(2-hydroxypropyl)valine in hemoglobin of exposed rats was also determined using a modified Edman degradation method followed by GC-HRMS analysis. The value obtained was 90.2 ± 10.3 pmol/mg globin. These data demonstrate that nasal respiratory tissue, which is the target tissue for carcinogenesis, has a much greater level of alkylation of DNA than non-target tissues. AU - Rios-Blanco, M.N.* AU - Faller, T.H. AU - Nakamura, J.* AU - Kessler, W. AU - Kreuzer, P.E. AU - Ranasinghe, A.* AU - Filser, J.G. AU - Swenberg, J.A.* C1 - 21555 C2 - 19680 SP - 2011-2018 TI - Quantitation of DNA and hemoglobin adducta and apurinic/apyrimidinic sites in tissue of F344 rats exposed to propylene oxide by inhalation. JO - Carcinogenesis VL - 21 IS - 11 PY - 2000 SN - 0143-3334 ER - TY - JOUR AB - Prostaglandins (PGs) have been implicated in tumor promotion. In this study, we investigated the effect of the hepatic tumor promoters lindane and phenobarbital (PB) on the PG metabolism of Kupffer cells in vitro and in vivo, in particular on the expression of cyclooxygenase (COX), the leading enzyme in prostanoid synthesis. Exposure of primary cultures of Kupffer cells to lindane for 1 h stimulated the production of the PGs PGE(2) and PGD(2) markedly (up to 50-fold) and that of PGF(2alpha) by >3-fold. This effect was accompanied by an increase in the COX-2 protein, as demonstrated by western blotting. Similarly, PB, which shares several effects with lindane in rat liver, also clearly induced COX-2. Lindane and PB affected the PG synthesis in vitro and in vivo in Kupffer cells of rats that had been treated with the two compounds for 56 days. Kupffer cells, which were isolated at days 2, 5 and 56 of the treatment, showed a significant increase in the levels of COX-2 mRNA and protein. Total COX activity was increased approximately 2-fold and 3- to 5-fold in Kupffer cell homogenates of PB- and lindane-treated animals, respectively, compared with the untreated controls. These results suggest that paracrine mechanisms may contribute to the tumor-promoting activity of lindane and PB, stimulating the production of PGs by Kupffer cells. AU - Kroll, B. AU - Kunz, S. AU - Klein, T.* AU - Schwarz, L.R. C1 - 23955 C2 - 31422 SP - 1411-1416 TI - Effect of lindane and phenobarbital on cyclooxygenase-2 expression and prostanoid synthesis by Kupffer cells. JO - Carcinogenesis VL - 20 IS - 8 PB - Oxford Univ. Press PY - 1999 SN - 0143-3334 ER - TY - JOUR AB - The polycyclic aromatic hydrocarbon (PAH) dibenzo[a,l]pyrene (DB[a,l]P), the most carcinogenic PAH tested in rodent bioassays, exerts its pathobiological activity via metabolic formation of electrophilically reactive DNA-binding fjord region (+)-syn-(11S,12R,13S,14R)- or (-)-anti-(11R,12S,13S,14R)-DB[a,l]P-dihydrodiol epoxides (DB[a,l]-PDEs). DB[a,l]P is metabolized to these DB[a,l]PDEs which bind to DNA in human mammary carcinoma MCF-7 cells. The molecular response of MCF-7 cells to DNA damage caused by DB[a,l]PDEs was investigated by analyzing effects on the expression of the tumor suppressor protein p53 and one of its target gene products, the cyclin-dependent kinase inhibitor p21WAF1. Treatment of MCF-7 cells with (+)-syn- and (-)-anti-DB[a,l]PDE at a concentration range of 0.001-0.1 microM resulted in DB[a,l]PDE-DNA adduct levels between 2 and 30, and 3 and 80 pmol/mg DNA, respectively, 8 h after exposure. (-)-anti-DB[a,l]PDE exhibited a higher binding efficiency that correlated with a significantly stronger p53 response at low concentrations of the dihydrodiol epoxides. The level of p53 increased by 6-8 h after treatment. The p21WAF1 protein amount exceeded control levels by 12 h and remained elevated for 96 h. At a dose of 0.01 microM (+)-syn-DB[a,l]PDE, an increase in p21WAF1 was observed in the absence of a detectable change in p53 levels. The results indicate that the increase in p53 induced by DB[a,l]PDEs in MCF-7 cells requires an adduct level of approximately 15 pmot/mg DNA and suggest that the level of adducts rather than the specific structure of the DB[a,l]PDE-DNA adduct formed triggers the p53 response. The PAH-DNA adduct level formed may determine whether p53 and p21VAF1 pathways respond, resulting in cell-cycle arrest, or fail to respond and increase the risk of mutation induction by these DNA lesions. AU - Luch, A.* AU - Kudla, K.* AU - Seidel, A.* AU - Doehmer, J.* AU - Greim, H. AU - Baird, W.M.* C1 - 23985 C2 - 31429 SP - 859-865 TI - The level of DNA modification by (+)-syn-(11S,12R,13S,14R)- and (-)-anti-(11R,12S,13S,14R)-dihydrodiol epoxides of dibenzo[a,l]pyrene determined the effect on the proteins p53 and p21WAF1 in the human mammary carcinoma cell line MCF-7. JO - Carcinogenesis VL - 20 IS - 5 PB - Oxford Univ. Press PY - 1999 SN - 0143-3334 ER - TY - JOUR AB - The gestagenic and antiandrogenic drug cyproterone acetate (CPA) is mitogenic, tumorigenic and induces DNA-adducts and DNA-repair synthesis in rat liver. Thus CPA is expected to be mutagenic. However in vitro mutagenicity test systems were negative. To examine whether CPA induces mutations in rat liver, the in vivo mutation assay based on Big Blue transgenic F344 rats was employed. Single oral doses of 25, 50, 75, 100 and 200 mg CPA/kg b.w. respectively were administered to female Big Blue rats. Six weeks after treatment, liver DNA was assayed for mutations. At the highest dose, 200 mg CPA/kg b.w., the frequency of (17 +/- 4) x 10(-6) spontaneous mutations was increased to a maximum of (80 +/- 8) x 10(-6) mutations. One-hundred and 75 mg CPA/kg b.w. resulted in mutation frequencies of (35 +/- 5) and (27 +/- 5) x 10(-6), respectively. The mutation frequency at doses of 50 and 25 mg CPA/kg b.w. was similar to that of vehicle treated controls. Statistical analysis of the dose-effect relationship revealed that it was not possible to decide whether a threshold dose exists or not. DNA adducts were analyzed by the 32P-postlabelling technique. The total level of the major and the two minor adducts observed in the autoradiograms increased between doses of 25 to 75 mg CPA/kg b.w. to a maximum of approximately 12,000 +/- 3000 adducts per 10(9) nucleotides. The level did not further increase significantly with 100 and 200 mg CPA/kg b.w. After CPA treatment no preneoplastic liver foci were observed. However, single glutathione-S-transferase placental form (GST-P) positive hepatocytes were observed and the frequency was dependent on the dose. These cells are not supposed to represent initiated cells, since they occurred only transiently after 6 weeks and disappeared thereafter completely. In conclusion, our results demonstrate that CPA is mutagenic in vivo. The mutation frequency increased at high CPA doses, when the increase of the DNA adduct formation had already ceased. This suggests that the mitogenic activity of CPA is required to express the mutations. AU - Krebs, O.* AU - Schäfer, B. AU - Wolff, T.* AU - Oesterle, D.* AU - Deml, E. AU - Sund, M. AU - Favor, J. C1 - 24163 C2 - 31448 SP - 241-245 TI - The DNA damaging drug cyproterone acetate causes gene mutations and induces glutathione-S-transferase P in the liver of female Big BlueTM transgenic F344 rats. JO - Carcinogenesis VL - 19 IS - 2 PB - Oxford Univ. Press PY - 1998 SN - 0143-3334 ER - TY - JOUR AB - Peroxisome proliferators (PPs) have been shown to cause tumours in rodent liver. The mechanism of action of these chemicals is only poorly understood. Current evidence, however, suggests that they may cause tumours through a tumour promoting activity. In the present study we therefore evaluated the effect of three peroxisome proliferators on gap junctional intercellular communication (IC) of cultured hepatocytes. Interference with IC is thought to be one of the mechanisms involved in tumour promotion. IC was detected by dye coupling of hepatocytes using microinjection of Lucifer Yellow CH. Five hours after plating, coupling of the cells amounted to ~90%. Incubation of hepatocytes with the PPs mono(2-ethylhexyl)phthalate (MEHP), nafenopin and [4-chloro-6-(2,3- xylidino)-2-pyrimidylthio]acetic acid (Wy-14,643) decreased dye coupling of the hepatocytes. Half maximal effects were obtained at ~50 μM nafenopin, 150 μM Wy-14,643 and 200 μM MEHP. Addition of the specific inhibitor of Ca22+-dependent protein kinase C isoenzymes, Go 6976 (2 μM) prevented inhibition of IC by nafenopin, but not by the two other peroxisome proliferators. Further studies suggest significant differences in the mechanisms underlying inhibition of dye coupling between hepatocytes by nafenopin and by phenobarbital, a known tumour promoter in the liver. The results show that the PPs nafenopin, MEHP and Wy-14,643 decrease IC between cultured hepatocytes. Inhibition of IC by nafenopin, but not by MEHP and Wy-14,643, is most likely mediated by Ca2+-dependent protein kinase C isoenzymes. AU - Leibold, E. AU - Greim, H.A. AU - Schwarz, L.R. C1 - 40042 C2 - 37856 SP - 1265-1269 TI - Inhibition of intercellular communication of rat hepatocytes by nafenopin: Involvement of protein kinase C. JO - Carcinogenesis VL - 15 IS - 6 PY - 1994 SN - 0143-3334 ER - TY - JOUR AB - The response to a number of agents has been compared in two short-term assays used for the detection of virus inducers and tumor promoters: (i) induction of the EBV-DR-promoter in Raji cells, as measured by DR-CAT induction (DR-CAT test) and (ii) induction of the oxidative burst in human PMN, as measured by chemiluminescence in the presence of luminol or lucigenin (CL test). In order to validate the two assays, we have investigated the responses to 12-O-tetradecanoyl-phorbol-13-acetate (TPA), 1,2-dioctanoylglycerol (DAG), phospholipase C (PLC EC-3-1-4-30) and ionophore A23187, which are active in both systems: arachidonic acid, linoleic acid and NaCl were found active only in the CL test. Staurosporine (protein kinase inhibitor), tamoxifen (estrogen antagonist and protein kinase C inhibitor), forskolin (protein kinase A activator), R59949 (diacylglycerol kinase inhibitor), curcumin and N-acetyl-L-cysteine (scavengers of reactive oxygen species) and NaCl acted as inhibitors. A good concordance of the EC50 values of inducing substances was found between the two assays, except for A23187 and DAG, which were required at much higher concentrations in the DR-CAT test. The inhibition patterns by the panel of inhibitors revealed similarities and discrepancies in the induction pathways between the two systems, providing information on their mode of action. The two assays, which complement each other, were shown to detect a number of known or suspected EBV inducers or tumor promoters, and thus appear useful for screening of new compounds or mixtures as well as of potential antiviral and antipromoting substances. AU - Bouvier, G. AU - Hergenhahn, M. AU - Polack, A. AU - Bornkamm, G.W. AU - Bartsch, H. C1 - 20502 C2 - 13711 SP - 1573-1578 TI - Validation of two Test Systems for Detecting Tumour Promoters and EBV Inducers: Comparative Responses of Several Agents in DR-CAT Raji Cells and in Human Granulocytes. JO - Carcinogenesis VL - 14 IS - 8 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - The response to a number of agents has been compared in two short-term assays used for the detection of virus inducers and tumor promoters: (i) induction of the EBV-DR-promoter in Raji cells, as measured by DR-CAT induction (DR-CAT test) and (ii) induction of the oxidative burst in human PMN, as measured by chemiluminescence in the presence of luminol or lucigenin (CL test). In order to validate the two assays, we have investigated the responses to 12-O-tetradecanoylphorbol-13-acetate (TPA), 1,2-dioctanoylglycerol (DAG), phospholipase C (PLC EC-3-1-4-30) and ionophore A23187, which are active in both systems; arachidonic acid, linoleic acid and NaCl were found active only in the CL test. Staurosporine (protein kinase inhibitor), tamoxifen (estrogen antagonist and protein kinase C inhibitor), forskolin (protein kinase A activator), R59949 (diacylglycerol kinase inhibitor), curcumin and N-acetyl-L-cysteine (scavengers of reactive oxygen species) and NaCl acted as inhibitors. A good concordance of the EC50 values of inducing substances was found between the two assays, except for A23187 and DAG, which were required at much higher concentrations in the DR-CAT test. The inhibition patterns by the panel of inhibitors revealed similarities and discrepancies in the induction pathways between the two systems, providing information on their mode of action. The two assays, which complement each other, were shown to detect a number of known or suspected EBV inducers or tumor promoters, and thus appear useful for screening of new compounds or mixtures as well as of potential antiviral and antipromoting substances. AU - Bouvier, G.* AU - Hergenhahn, M.* AU - Polack, A. AU - Bornkamm, G.W. AU - Bartsch, H.* C1 - 40276 C2 - 40002 SP - 1573-1578 TI - Validation of two test systems for detecting tumor promoters and EBV inducers: Comparative responses of several agents in DR-CAT Raji cells and in human granulocytes. JO - Carcinogenesis VL - 14 IS - 8 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - Cyproterone acetate (CPA) is a synthetic steroid which is used in oral contraceptive and anti-androgen formulations. It has previously been classified as a tumor promoter in rat liver. Recent studies have shown that CPA induces DNA repair synthesis in isolated hepatocytes, and this implies that CPA is genotoxic. We studied the initiating activity of CPA in vivo by means of a rat liver foci bioassay, using weanling female Sprague-Dawley rats. The results show that CPA induces adenosine-triphosphatase-deficient and γ-glutamyltranspeptidase-positive putative preneoplastic foci in a dose-dependent manner. This indicates that CPA has not only promoting but also initiating activity and may therefore act as a complete carcinogen in rat liver. AU - Deml, E. AU - Schwarz, L.R. AU - Oesterle, D. C1 - 40248 C2 - 40011 SP - 1229-1231 TI - Initiation of enzyme-altered foci by the synthetic steroid cyproterone acetate in rat liver foci bioassay. JO - Carcinogenesis VL - 14 IS - 6 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - Gap junctional intercellular communication (IC) was studied in γ-glutamyltranspeptidase (γ-GT)-positive and -negative hepatocytes isolated from carcinogen-treated rats. Putative preneoplastic γ-GT-positive hepatocytes were visualized in monolayer cultures by indirect immunofluorescence using anti-γ-GT-antibodies. IC was evaluated by studying dye coupling of the cells. γ-GT-positive hepatocytes showed a significantly lower dye coupling than did γ-GT-negative liver cells. Spread of the dye Lucifer Yellow CH to neighboring cells was decreased further by the tumor-promoting chemical phenobarbital in both cell types in vitro. Also treatment in vivo with the barbiturate significantly reduced dye coupling of hepatocytes. The findings suggest that as a result of their decreased ability to communicate, preneoplastic hepatocytes may escape from growth control and differentiation signals given out by surrounding 'normal' cells. AU - Leibold, E. AU - Schwarz, L.R. C1 - 40292 C2 - 38009 SP - 2127-2129 TI - Intercellular communication in primary cultures of putative preneoplastic and 'normal' hepatocytes. JO - Carcinogenesis VL - 14 IS - 10 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - Several tumour promoting chemicals have been shown to inhibit intercellular communication (IC) through gap junctions in cell cultures. In the present investigation we studied the effect of the hepatic tumour promoters phenobarbital (PB), 1,1,1-trichloro-2,2-(p-chlorophenyl)ethane (DDT) and γ-hexachlorocyclohexane (lindane) on IC in rat hepatocyte cultures. IC was evaluated by microinjection of fluorescent Lucifer Yellow CH dye and visualization of dye spread to adjacent hepatocytes. Incubation of hepatocytes with PB (2 mM), DDT (30 μM) and lindane (25 μM) decreased dye-coupling of the cells by about 30%, 42% and 35%, respectively; dye-coupling in untreated cultures was 88.1 ±0.7%. Inhibition of IC was reversible when the xenobiotics were removed from the medium. The antioxidant vitamin E (100 μM) prevented inhibition of dye-coupling by PB and lindane and partially that by DDT. Superoxide dismutase (100 units/μM) counteracted the effect on dye-coupling by PB, but not that by the insecticides. Similarly, the cyclo-oxygenase inhibitors indomethacin and aspirin only reversed the effect of PB on IC, but not that of DDT or lindane. As indicated by further experiments, prevention by non-steroidal anti-inflammatory agents of PB-induced inhibition of IC is most likely not mediated by inhibition of cyclo-oxygenase. The results indicate significant differences in the action of PB, DDT and lindane on IC in hepatocyte cultures. This is suggested by the differential effects of Superoxide dismutase and non-steroidal anti-inflammatory agents on the action of the three tumour promoting chemicals. Whereas Superoxide radicals may be involved in the inhibition of dye-coupling by PB, radical intermediates of the insecticides may be responsible for the decrease in dye-coupling by DDT and lindane. AU - Leibold, E. AU - Schwarz, L.R. C1 - 40433 C2 - 40051 SP - 2377-2382 TI - Inhibition of intercellular communication in rat hepatocytes by phenobarbital, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and γ-hexachlorocyclohexane (lindane): Modification by antioxidants and inhibitors of cyclo-oxygenase. JO - Carcinogenesis VL - 14 IS - 11 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - Cyproterone acetate (CPA), an active component of certain contraceptive and antiandrogenic drugs, has been shown recently to induce DNA repair synthesis in rat hepatocytes in vitro. In the present study we examined whether CPA can cause the formation of DNA adducts detectable by the 32P-postlabeling technique in hepatic cells in vitro and in vivo. Incubation of primary cultures of hepatocytes from male Wistar rats with CPA resulted in the occurrence of radioactive spots in the radiochromatograms of 32P-postlabeled DNA digests indicating the formation of two DNA adducts ('A' and 'B'). At 30 μM CPA, the highest concentration tested, ∼50 'A' adducts and five 'B' adducts were found per 109 nucleotides. DNA of hepatocyte cultures from female rats was found to contain adduct A and a minor adduct termed 'D', but adduct B was not observed. Between 1 and 10 μM CPA, the relative level of adduct A was ∼20-fold higher than the level observed in male hepatocytes. In vivo DNA adducts were detected almost exclusively in hepatic DNA. Hepatic DNA from male Wistar rats treated with single doses of CPA (1-100 mg/kg) by gavage, showed the major adducts A and B and two further spots of minor intensity ('C' and 'D') in the radiochromatograms. No adducts were detectable in extrahepatic tissues. The adduct pattern of liver DNA from females exposed to single oral doses between 0.1 and 30 mg CPA/kg body wt was similar to that observed in males; however, the relative levels for adducts A and D were ∼100-fold higher. In females, linear relationships between dose and adduct levels were observed for all four adducts. The present findings show that CPA causes damage to hepatic DNA not only in vitro, but also in vivo. Thus it appears possible that DNA adduct formation is involved in the formation of hepatic tumors during long-term treatment of rats with the synthetic steroid. AU - Topinka, J.* AU - Andrae, U. AU - Schwarz, L.R. AU - Wolff, T. C1 - 40371 C2 - 38000 SP - 423-427 TI - Cyproterone acetate generates DNA adducts in rat liver and in primary rat hepatocyte cultures. JO - Carcinogenesis VL - 14 IS - 3 PY - 1993 SN - 0143-3334 ER - TY - JOUR AB - Sequential treatment of partially hepatectomized male Wistar rats with diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) induces the emergence of diploid hepatocyte populations. These carcinogen-induced hepatocytes are thought to include the precursor cells of liver carcinomas that arise later in this treatment protocol. The growth of the diploid hepatocytes is promoted by AAF and it has been suggested that the action of the arylamine may be receptor-mediated. AAF has been shown to bind specifically to the aryl hydrocarbon (Ah) receptor and the so-called 4S polycyclic aromatic hydrocarbon (PAH) binding protein. The present study addresses the question of whether the concentrations of the two binding proteins differ in diploid and polyploid hepatocytes from DEN/AAF-treated rats. Hepatocytes from carcinogen-treated rats were isolated and diploid, and tetraploid hepatocytes separated by means of centrifugal elutriation. Whereas Ah receptor concentrations in diploid hepatocytes were insignificantly lower (21.8 +/- 5.9 versus 29.2 +/- 6.6 fmol/mg cytosolic protein; n = 4; P = 0.1), levels of the 4S PAH binding protein in diploid hepatocytes were twice as high as in tetraploid hepatocytes (252.3 +/- 93.6 versus 124.0 +/- 18.5 fmol/mg cytosolic protein; n = 4; P = 0.04). We conclude from our results that the differences in growth control in polyploid and carcinogen-induced diploid hepatocytes are not associated with changes in the levels of the Ah receptor. The role of the 4S PAH binding protein in the process of hepatocarcinogenesis remains to be established. AU - Cikryt, P. AU - Göttlicher, M. AU - Veser, U. AU - Schwarz, L.R. C1 - 19882 C2 - 13036 SP - 807-810 TI - The level of aryl hydrocarbon (Ah) receptor and of 4S polycyclic aromatic hydrocarbon (PAH) binding protein in diploid and polyploid hepatocytes of 2-acetylaminofluorene-treated rats. JO - Carcinogenesis VL - 13 IS - 5 PY - 1992 SN - 0143-3334 ER - TY - JOUR AB - 1,3-Butadiene (BD), a widely used monomer in the production of synthetic rubber and other resins, is one of the 189 hazardous air pollutants identified in the 1990 Clean Air Act Amendments. BD induces tumors at multiple organ sites in B6C3F1 mice and Sprague-Dawley rats; mice are much more susceptible to the carcinogenic action of BD than are rats. Previous in vivo studies have indicated higher circulating blood levels of butadiene monoepoxide (BMO), a potential carcinogenic metabolite of BD, in mice compared to rats, suggesting that species differences in the metabolism of BD may be responsible for the observed differences in carcinogenic susceptibility. The metabolic fate of BD in humans is unknown. The objective of these studies was to quantitate in vitro species differences in the oxidation of BD and BMO by cytochrome P450-dependent monooxygenases and the inactivation of BMO by epoxide hydrolases and glutathione S-transferases using microsomal and cytosolic preparations of livers and lungs obtained from Sprague-Dawley rats, B6C3F1 mice and humans. Maximum rates for BD oxidation (Vmax) were highest for mouse liver microsomes (2.6 nmol/ mg protein/min) compared to humans (1.2) and rats (0.6). The Vmax for BD oxidation by mouse lung microsomes was similar to that of mouse liver but > 10-fold higher than the Vmax for the reaction in human or rat lung microsomes. Correlation analysis revealed that P450 2E1 is the major P450 enzyme responsible for oxidation of BD to BMO. Only mouse liver microsomes displayed quantifiable rates for metabolism of BMO to butadiene diepoxide (Vmax = 0.2 nmol/mg protein/min), a known rodent carcinogen. Human liver microsomes displayed the highest rate of BMO hydrolysis by epoxide hydrolases. The Vmax in human liver microsomes ranged from 9 to 58 nmol/mg protein/min and was at least 2-fold higher than the Vmax observed in mouse and rat liver microsomes. The Vmax for glutathione S-transferase-catalyzed conjugation of BMO with glutathione was highest for mouse liver cytosol (500 nmol/mg protein/min) compared to human (45) or rat (241) liver cytosol. In general, the KMs for the detoxication reactions were 1000-fold higher than the KMs for the oxidation reaction. Because of the low solubility of the BD and the relatively high KM for oxidation, it is likely that the Vmax/KM, ratio will be important for BD and BMO metabolism in vivo. In vivo clearance constants were calculated from in vitro data for BD oxidation and BMO oxidation, hydrolysis and GSH conjugation. The overall activation/detoxication ratio was markedly different for mice (72), rats (5.8) and humans (5.9) and suggest that at concentrations below the KM for the reactions, mice have a significantly higher ratio of activation/detoxication than do either rats or humans. The differences in the activation/ detoxication ratios between mice and rats correlate with the higher carcinogenic sensitivity of mice than rats to BD. AU - Csanády, G.A. AU - Guengerich, F.P.* AU - Bond, J.A.* C1 - 40613 C2 - 38789 SP - 1143-1153 TI - Comparison of the biotransformation of 1,3-butadiene and its metabolite, butadiene monoepoxide, by hepatic and pulmonary tissues from humans, rats and mice. JO - Carcinogenesis VL - 13 IS - 7 PY - 1992 SN - 0143-3334 ER - TY - JOUR AB - The synthetic anti-androgen and progestin cyproterone acetate (CPA) is known to increase the liver tumor rate in rats. The tumorigenicity of CPA has been attributed to a tumor-promoting activity of the steroid. In order to discover whether CPA acts directly on preneoplastic liver cells or via indirect effects, we investigated whether CPA stimulates replicative DNA synthesis in vitro in hepatocytes isolated from carcinogen-treated rats (two-thirds hepatectomy, 1 x 30 mg diethylnitrosamine per kg and 0.1% phenobarbital in the drinking water) and whether the degree of stimulation differs in gamma-glutamyltranspeptidase (GGT)-positive, putatively preneoplastic and GGT-negative, 'normal' hepatocytes. The possibility that CPA might also have initiating potential was investigated by studying its effects on DNA repair synthesis. Stimulation of [3H]thymidine incorporation into the DNA by CPA was only observed in the presence of epidermal growth factor (EGF) (10 ng/ml) and insulin (10 mU/ml). Maximal effects were obtained between 2 and 10 microM. DNA synthesis in the presence of EGF/insulin was reduced by the 'pure' anti-androgen flutamide, but stimulated by the 'pure' progestin promegestone. In the presence of CPA, EGF and insulin, the labelling index was twice as high in GGT-positive as in GGT-negative liver cells, regardless of whether mitogens were added at 48 or 72 h. The labelling index did not differ in the GGT-positive and negative hepatocytes when CPA was omitted. These findings are consistent with the idea that CPA has tumor-promoting activity. CPA significantly induced repair synthesis in the isolated hepatocytes from both untreated and carcinogen-treated rats. This increase was detected at a concentration as low as 2 microM and maximal effects were obtained at 20 microM. These results indicate that CPA is not only a tumor-promoting, but also a genotoxic chemical, i.e. that it might also have an initiating potential. AU - Neumann, I. AU - Thierau, D. AU - Andrae, U. AU - Greim, H. AU - Schwarz, L.R. C1 - 19756 C2 - 12903 SP - 373-378 TI - Cyproterone acetate induces DNA damage in cultured rat hepatocytes and preferentially stimulates DNA synthesis in gamma-glutamyltranspeptidase-positive cells. JO - Carcinogenesis VL - 13 IS - 3 PY - 1992 SN - 0143-3334 ER - TY - JOUR AB - The effect of di(2-ethylhexyl)phthalate (DEHP) on diethylnitrosamine (DEN)-initiated preneoplastic liver lesions with expression of gamma-glutamyltranspeptidase (GGTase) and loss of adenosine triphosphatase (ATPase) as well as alterations of hepatic carbohydrate metabolism in male and female Sprague-Dawley rats have been investigated. Two treatment schedules have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic islands and by the biochemical determination of alterations in enzyme activities of liver homogenates and of serum, the last indicating hepatotoxicity. For initiation, a single dose of DEN was given, followed by treatment with various doses of DEHP given three times weekly by gavage for 7 or 11 consecutive weeks. As histochemical enzyme markers, the expression of positive GGTase as well as the deficiency in ATPase were used for identification of liver foci. The weanling female rats (protocol A) were found to be more sensitive to the carcinogenic effect of DEN in view of foci incidence than the mature male rats which underwent partial hepatectomy prior to DEN application. The administration of 200 mg DEHP/kg body wt increased the incidence of ATPase-deficient foci in both male and female rats; however, concentrations of 1000 and 2000 mg DEHP/kg decreased the incidence of liver foci. The number of foci with expression of GGTase was only slightly increased in female rats following a DEHP concentration of 50 mg/kg, and 200 mg/kg body wt. DEHP alone did not induce preneoplastic lesions that could be identified by these two markers. Biochemical investigations indicate that DEHP alters the metabolic pattern in liver. An increase of the NADP-linked enzymes glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme, extra-mitochondrial ICDH as well as an enhancement of NAD-dependent α-G3PDH and lactate dehydrogenase were found following DEHP administration. On the other hand the glycolytic enzymes pyruvate kinase (PK) and enolase as well as the gluconeogenetic enzyme fructose-1,6-bisphosphatase (FBPase) were significantly reduced. In protocol B (male rats) the reactions of PK, FBPase and malic enzyme were more altered after DEHP exposure than in protocol A, while the activity of G6PDH was more increased in protocol A. Most enzymes being involved in the carbohydrate metabolism are influenced by DEHP in a dose-dependent manner. There was no increase in serum FBPase activity in both male and female rats after DEHP treatment but a reduction of glutamate-oxalate-transaminase and glutamate-pyruvate-transaminase activities was observed. This and the fact that the control and DEHP-treated animals had similar weight gains indicate that DEHP does not exert a significant hepatotoxicity effect. AU - Gerbracht, U.* AU - Einig, C.* AU - Oesterle, D.* AU - Deml, E.* AU - Schlatterer, B. AU - Eigenbrodt, E.* C1 - 41978 C2 - 34276 SP - 2111-2115 TI - Di(2-ethylhexyl)phthalate alters carbohydrate enzyme activities and foci incidence in rat liver. JO - Carcinogenesis VL - 11 IS - 12 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - The role of the Ah receptor in mediating the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was investigated in 5L rat hepatoma cells containing TCDD-inducible cytochrome P450IA1 activity and in variants lacking cytochrome P450IA1 and Ah receptor. TCDD inhibited growth of the wild-type 5L cells, but not of the Ah receptor deficient variants. The two strong Ah receptor ligands 3,3',4,4'-tetrachlorobiphenyl (3,3',4,4'-TCB) and benz[a]anthracene (BA) exerted toxic effects in 5L cells that resembled those of TCDD. The poor Ah receptor ligand 2,2',4,4'-tetrachlorobiphenyl was not toxic in 5L cells. The concentrations of TCDD, 3,3',4,4'-TCB or BA required for the toxic response were similar to those that elicited P450IA1 induction. The present results suggest strongly that interaction with the Ah receptor is a necessary link in the chain of events leading to toxic effects in 5L cells upon exposure to TCDD. AU - Göttlicher, M. AU - Cikryt, P. AU - Wiebel, F.J. C1 - 42624 C2 - 34271 SP - 2205-2210 TI - Inhibition of growth by 2,3,7,8-tetrachlorodibenzo-p-dioxin in 5L rat hepatoma cells is associated with the presence of Ah receptor. JO - Carcinogenesis VL - 11 IS - 12 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - Diploid hepatocytes induced by a combination of diethylnitrosamine and 2-acetylaminofluorene were isolated and separated from polyploid hepatocytes by centrifugal elutriation. The diploid and polyploid cell fractions were approximately 90% pure and contained between 1 and 1.5 x 10(7) cells. When kept in monolayer cultures both cell populations responded to the mitogenic effect of EGF and insulin. However, the percentage of labelled nuclei was higher in predominantly diploid compared to predominantly tetraploid hepatocyte cultures at all epidermal growth factor (EGF) concentrations used in this study. At 10 ng EGF/ml and 10 mU insulin/ml the labelling index was twice as high in the diploid liver cells. Further work is required to show the relevance of the stronger response of the diploid cell fraction to mitogens in the process of carcinogenesis. AU - Klose, U. AU - Thierau, D. AU - Veser, U. AU - Schwarz, L.R. C1 - 18359 C2 - 11550 SP - 1479-1483 TI - Stimulation of DNA-Synthesis in Carcinogen-Induced Diploid Hepatocytes in vitro. JO - Carcinogenesis VL - 11 IS - 9 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - Diploid hepatocytes induced by a combination of diethylnitrosamine and 2-acetylaminofluorene were isolated and separated from polyploid hepatocytes by centrifugal elutriation. The diploid and polyploid cell fractions were ~90% pure and contained between 1 and 1.5 x 107 cells. When kept in monolayer cultures both cell populations responded to the mitogenic effect of EGF and insulin. However, the percentage of labelled nuclei was higher in predominantly diploid compared to predominantly tetraploid hepatocyte cultures at all epidermal growth factor (EGF) concentrations used in this study. At 10 ng EGF/ml and 10 mU insulin/ml the labelling index was twice as high in the diploid liver cells. Further work is required to show the relevance of the stronger response of the diploid cell fraction to mitogens in the process of carcinogenesis. AU - Klose, U. AU - Theirau, D. AU - Veser, U. AU - Schwartz, L.R. C1 - 40855 C2 - 0 SP - 1479-1483 TI - Stimulation of DNA synthesis in carcinogen-induced diploid hepatocytes in vitro. JO - Carcinogenesis VL - 11 IS - 9 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - Ethylnitrosourea (ENU) was diaplacentally applied to (T X HT)F1 mice at a dose of 40 mg/kg on different gestation days during organogenesis and early fetal stages by i.p. injection to the dams. The animals were particularly sensitive to induction of tumours at the central nervous system (CNS)-skull-vertebra interface (30 and 20% in ENU-treated male and female offspring respectively, compared with 1% in controls). ENU treatment during the late organogenesis stage (gestation days 8-11) proved to be less efficient in tumour induction than during the subsequent early fetal period (gestation days 12-14). Ninety-two per cent of the CNS tumours were located at the interface between the CNS and the osseous surrounding. The distribution of these tumours at the pial border was inhomogeneous: 69% were found at the brain-skull border, 6% of the tumours occurred within the cervico-thoracal districts and 25% within the lumbo-sacral districts of the spinal cord-vertebra interface. Histological classification revealed a preferential occurrence of neuroepithelial tumours in male offspring (approximately 20%) and only approximately 7% Schwann cell tumours and approximately 3% tumours of meningomesenchymal origin. In female offspring neuroepithelial tumours and Schwann cell tumours were observed at about an equal rate (9-10%), in contrast to meningo-mesenchymal tumours (1%). Nearly 98% of these tumours were situated at the basal districts of the space between the CNS-skull and spinal cord-vertebra. This indicates a particular sensitivity of the basal neurothelium, a derivative of neural crest cells, for ENU-induced carcinogenesis. The pluripotency of these cells during the mid-gestation period apparently enables growth of different histopathological tumour types, which arise independently from each other. AU - Schmahl, W. AU - Luz, A. AU - Leierseder-Bauer, M. AU - Neuhäuser-Klaus, A. C1 - 18225 C2 - 11438 SP - 1313-1322 TI - Diaplacental Induction by Ethylnitrosourea of Tumours at the Pial Border of the Central Nervous System in (T x HT)F1 Mice. JO - Carcinogenesis VL - 11 IS - 8 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - Human blood cells, separated by Ficoll-Hypaque centrifugation, were tested for their ability to catalyze the formation of DNA adducts of 2-aminofluorene (AF), using the 32P-postlabeling procedure for adduct analysis. Incubation of neutrophils with AF, hydrogen peroxide and exogenous DNA yielded a single DNA adduct identified as C8-(N2-aminofluorenyl)-deoxyguanosine-3'-5'-diphosphate (AFdG) by cochromatography with a standard sample. AFdG levels in intact cells, lysed cells and in the granule fraction prepared from cell lysates were 102, 894 and 240 AFdG adducts/10(9) nucleotides/30 min respectively. AFdG levels corresponded to the activity of neutrophil peroxidase in these preparations. The monocyte/lymphocyte fraction yielded a low amount of 30 and 40 AFdG/10(9) nucleotides/30 min in the presence of hydrogen peroxide and of NADPH respectively. Erythrocytes did not generate a detectable level of AFdG, neither as intact cells nor as cell lysates. Whole blood samples likewise did not generate AFdG. Our findings reveal that, among blood cells, only neutrophils are capable of forming a biologically significant DNA adduct of aminofluorene in reasonable amounts and suggest that myeloperoxidase was the catalyzing enzyme. AU - Wolff, T. AU - Shen, J.H. AU - Wegenke, M. C1 - 18276 C2 - 11497 SP - 1441-1444 TI - Capability of Human Blood Cells to Form the DNA-adduct, C8-(N2-aminofluorenyl) Deoxyguanosine, from 2-aminofluorene. JO - Carcinogenesis VL - 11 IS - 8 PY - 1990 SN - 0143-3334 ER - TY - JOUR AB - The genotoxicity of 2-nitropropane (2-NP) and 1-nitropropane (1-NP) was investigated by measuring the induction of DNA repair synthesis in rat liver cells in vitro and in vivo. 2-NP strongly induced DNA repair synthesis in both cases. When applied in vivo, 2-NP was considerably more effective in hepatocytes from males than in those from females. 1-NP was not active in vitro or in vivo. 2-NP and 1-NP did not induce repair in cell lines of extrahepatic origin derived from rat, mouse, hamster and man. The results are consistent with the reported carcinogenicity of 2-NP in rat liver and suggest that the formation of hepatocarcinomas by 2-NP is due to the generation of a genotoxic metabolite from 2-NP by liver-specific metabolism. AU - Andrae, U. AU - Homfeldt, H. AU - Vogl, L. AU - Lichtmannegger, J. AU - Summer, K.H. C1 - 18175 C2 - 11039 SP - 811-815 TI - 2-Nitropropane induced DNA Repair Synthesis in Rat Hepatocytes in Vitro and in Vivo. JO - Carcinogenesis VL - 9 IS - 5 PY - 1989 SN - 0143-3334 ER - TY - JOUR AU - Hesse, S. AU - Cumpelik, O. AU - Krupski-Brennstuhl, G. AU - Mezger, M. AU - Wiebel, F.J. C1 - 17588 C2 - 10803 TI - Selective Trapping by Glutathione Conjugation of the Benzo(a)pyrene-7,8-diol-9,10-epoxide Moeties which bind to DNA. JO - Carcinogenesis PY - 1989 SN - 0143-3334 ER - TY - JOUR AB - Treatment of male Wistar rats with 2-acetylaminofluorene (2-AAF) markedly altered the ploidy distribution of liver cells. Small diploid hepatocytes first appeared after 4-5 weeks feeding of a diet containing 0.02% 2-AAF; after 9 weeks 65-70% of the hepatocytes were diploid. Approximately two-thirds of this new liver cell population persisted after termination of the treatment. The hepatocytes from 2-AAF treated animals were separated according to size and ploidy by centrifugal elutriation and stained for gamma-glutamyltranspeptidase (gamma-GTase). The percentage of gamma-GTase-positive hepatocytes did not significantly differ between the various elutriated cell fractions. Thus gamma-GTase-positive liver cells obtained by feeding of 2-AAF do not represent a distinct size class of hepatocytes. The significance of carcinogen-induced diploid hepatocytes in hepatocarcinogenesis is discussed. AU - Klose, U. AU - Thierau, D. AU - Greim, H.A. AU - Schwarz, L.R. C1 - 41692 C2 - 38209 SP - 553-556 TI - Centrifugal elutriation of hepatocytes from 2-acetylaminofluorene-treated rats and their characterization by flow cytometry. JO - Carcinogenesis VL - 10 IS - 3 PY - 1989 SN - 0143-3334 ER - TY - JOUR AB - Three rat liver foci bioassays have been compared with respect to their sensitivity by the histochemical demonstration of preneoplastic foci, and by the biochemical determination of alterations in enzyme activities of serum indicating hepatotoxicity. We studied the initiation/promotion schedules according to Oesterle and Deml (A), and according to Pereira (B, Broad Spectrum Protocol), and the initiation/selection protocol according to Tatematsu et al. (C), with diethylnitrosamine (DEN), given as a single initiating dose of 10 and 30 mg/kg body wt respectively. With all schedules Sprague-Dawley rats, either females, 3 weeks old (A), or males, 6 weeks old (B, C) were used. For promotion polychlorinated biphenyls (A) or phenobarbital (B) were administered. Selection was performed with 2-acetylaminofluorene (C). The rats in schemes (B) and (C) underwent partial hepatectomy one day prior to initiation. The number and total area of foci deficient in adenosine-5'-triphosphatase (ATPase) and positive in gamma-glutamyltranspeptidase (GGTase) was evaluated. In the complete schedule with 30 mg of DEN in system (A) foci incidence exceeded that of the other systems by about 7-fold (ATPase) and 2-fold (GGTase) respectively. The lower dose of DEN and all control experiments resulted in a respective lower foci yield. With scheme (C), but not with schemes (A) and (B), e.g. serum fructose-1.6-bisphosphatase and alkaline phosphatase were increased, suggesting liver cell damage. Thus tested with DEN, scheme (A) is most sensitive and causes a low impairment of animals' welfare. AU - Oesterle, D. AU - Gerbracht, U. AU - Deml, E. AU - Schlatterer, B. AU - Eigenbrodt, E. C1 - 17835 C2 - 10744 SP - 1891-1895 TI - Comparison of Three Rat Liver Foci Bioassays - Incidence of Preneoplastic Foci Initiated by Diethylnitrosamine. JO - Carcinogenesis VL - 10 PY - 1989 SN - 0143-3334 ER - TY - JOUR AB - Three carcinoma-associated oncogenes, two of which have been strongly implicated in human mammary tumorigenesis, have been introduced into a novel mouse mammary epithelial cell line, EF43, that retains many differentiated functions. The effect of oncogene expression upon classical transformation parameters as well as parameters specific for mammary epithelial cells such as growth in three-dimensional collagen matrices and the ability to repopulate the cleared mammary fat pad and to form alveolar structures in vivo has been investigated. Expression of v-myc in EF43 cells results in no obvious phenotypic changes, and does not confer tumorigenic potential upon the cells. Expression of v-Ha-ras confers upon EF43 cells the ability to grow rapidly, grow in an anchorage-independent manner, results in tumor formation in nude and syngeneic animals, abolishes their ability to repopulate the mammary gland and, instead, results in rapid induction of anaplastic tumors. The v-mil oncogene, an avian homolog of the mouse v-mht and human c-raf oncogenes, previously thought to be non-transforming in the absence of a co-operating oncogene, transforms EF43 cells, allowing them to grow in an anchorage-independent manner, form tumors in nude mice and abolishes their ability to repopulate the cleared mammary fat pad. In contrast to v-ras, however, the tumors arising from v-mil expression have a differentiated morphology, typical of adenocarcinomas. Thus, different oncogenes show varying degrees of inhibition of the differentiation of mammary epithelial cells in vivo. AU - Günzburg, W.H. AU - Salmons, B. AU - Schlaeffli, A. AU - Moritz-Legrand, S. AU - Jones, W. AU - Sarkar, N.H. AU - Ullrich, N. C1 - 17466 C2 - 10370 SP - 1849-1856 TI - Expression of the oncogenes mil and ras abolishes the in vivo differentiation of mammary epithelial cells. JO - Carcinogenesis VL - 9 IS - 10 PY - 1988 SN - 0143-3334 ER - TY - JOUR AB - Mice were X-irradiated on day 15 of gestation with 0.2, 0.4, 0.8 or 1.6 Gy. Offspring were reared by their mothers and divided into two subgroups at an age of 21 days, one subgroup receiving a single dose (45 mg/kg) of ethylnitrosourea (ENU). All animals were kept ultimately until 22 months to register the long-term tumour pattern. The carcinogenic effects of ENU alone were also studied in two separate experiments. Prenatal X-irradiation with 1.6 Gy mostly abolished the carcinogenic late effects of ENU, with the exception of an almost constant leucosis incidence and an unchanged lung tumour frequency. Lowering the prenatal X-ray dose to 0.8 Gy resulted in a significantly increased rate of liver tumours and ovary tumours. Synergistic effects on various tissues were observed after both 0.4- and 0.2-Gy foetal X-irradiation treatment in combination with postnatal application of ENU. These effects mainly involved a significant increase in the frequency of leucosis and of tumours of the liver, intestine, uterus and ovaries. The greater-than-additive effect in the case of these tumours suggests that low-level prenatal X-irradiation leads to a lasting sensitivity of some tissues towards a subsequent carcinogenic stimulus. AU - Schmahl, W. C1 - 17273 C2 - 10141 SP - 1493-1498 TI - Synergistic induction of tumours in NMRI mice by combined foetal X-irradiation with low doses and ethylnitrosourea administered to juvenile offspring. JO - Carcinogenesis VL - 9 IS - 8 PB - Oxford Univ. Press PY - 1988 SN - 0143-3334 ER - TY - JOUR AB - Mice were X-irradiated on day 15 of gestation with 0.2, 0.4, 0.8 or 1.6 Gy. Offspring were reared by their mothers and divided into two subgroups at an age of 21 days, one subgroup receiving a single dose (45 mg/kg) of ethylnitrosourea (ENU). All animals were kept ultimately until 22 months to register the long-term tumour pattern. The carcinogenic effects of ENU alone were also studied in two separate experiments. Prenatal X-irradiation with 1.6 Gy mostly abolished the carcinogenic late effects of ENU, with the exception of an almost constant leucosis incidence and an unchanged lung tumour frequency. Lowering the prenatal X-ray dose to 0.8 Gy resulted in a significantly increased rate of liver tumours and ovary tumours. Synergistic effects on various tissues were observed after both 0.4- and 0.2-Gy foetal X-irradiation treatment in combination with postnatal application of ENU. These effects mainly involved a significant increase in the frequency of leucosis and of tumours of the liver, intestine, uterus and ovaries. The greater-than-additive effect in the case of these tumours suggests that low-level prenatal X-irradiation leads to a lasting sensitivity of some tissues towards a subsequent carcinogenic stimulus. AU - Schmahl, W.G. C1 - 42464 C2 - 36260 SP - 1493-1498 TI - Synergistic induction of tumours in NMRI mice by combined foetal X-irradiation with low doses and ethylnitrosourea administered to juvenile offspring. JO - Carcinogenesis VL - 9 IS - 8 PY - 1988 SN - 0143-3334 ER - TY - JOUR AB - The effect of the technical mixture of polychlorinated biphenyls (PCBs) Clophen A 50 on the appearance of enzyme-altered islands initiated by diethylnitrosamine (DEN) in livers of 6 and 3 weeks old female Sprague-Dawley rats was studied. The loss of adenosine-5'-triphosphatase (ATPase), the emergence of gamma-glutamyltranspeptidase (GGTase), and the glycogen storage were used as histochemical markers. Islands were initiated by gastric intubation of 12 X 8 mg DEN/kg body weight/day in adults, or with 1 X 8 mg DEN/kg body weight in weanlings. Clophen A 50 alone initiated only few islands. A dose-dependent enhancement in number and area of islands by an additional treatment with Clophen A 50 of DEN-pretreated animals (2-100 mg/kg body weight/weekly, for 7 weeks) was observed in both age groups. In adults, doses between 2 and 100 mg/kg body weight increased number and area of ATPase-deficient islands 2 to 12-fold. In weanlings, application of 10-100 mg/kg body weight resulted in an increase of number and area up to 7- and 12-fold, respectively. No promoting effect was found with 2 mg/kg body weight compared to DEN-treated weanlings. The number of islands with coincidence of the three histochemical markers was enhanced dose-dependently in adults, and less marked also in weanlings after the application of the promoter. AU - Oesterle, D. AU - Deml, E. C1 - 41740 C2 - 38471 SP - 351-355 TI - Dose-dependent promoting effect of polychlorinated biphenyls on enzyme-altered islands in livers of adult and weanling rats. JO - Carcinogenesis VL - 5 IS - 3 PY - 1984 SN - 0143-3334 ER - TY - JOUR AB - The promoting effect of Clophen A 50, a commercial mixture of polychlorinated biphenyls (PCBs) on preneoplastic islands, initiated by diethylnitrosamine (DEN), was studied in male and female Sprague-Dawley rats. The islands were identified histochemically by loss of adenosine-5' -triphosphatase (ATPase) and/or emergence of gamma-glutamyltranspeptidase (GGTase). Treatment with 12 x 8 mg DEN/kg body wt./day initiated a similar number and total area of islands in males and females. Additional weekly application of Clophen A 50 (50 or 100 mg/kg body wt./week, for 7 weeks) enhanced the number of ATPase-deficient islands 3-fold in males and 9-fold in females. The total area was increased 4-fold in males and 15-fold in females. Number and area of GGTase-positive islands were similarly enhanced. The emergence of a small number of islands after application of Clophen A 50 alone may indicate a weak carcinogenic potency. PCB treatment caused an increase in liver weight, which amounted to ~55% in males and 20% in females compared to controls. This increase is partly due to cell hypertrophy, as indicated by determination of cell size. The mitogenic activity of Clophen A 50 was evaluated by measurement of the mitotic index of unaltered hepatocytes at 24, 48 h, 7 days after application of a single dose (100/mg/kg body wt.) of Clophen A 50. The mitotic index in control animals of both sexes was ~0.3%, and was enhanced 8-fold in males, 24 h after PCB treatment. In females only a slight, non-significant increase was observed. The results indicate that the sex-dependent promoting effect of Clophen A 50 is independent from its mitogenic action. AU - Deml, E. AU - Oesterle, D. C1 - 41699 C2 - 38426 SP - 1449-1452 TI - Sex-dependent promoting effect of polychlorinated biphenyls on enzyme-altered islands induced by diethylnitrosamine in rat liver. JO - Carcinogenesis VL - 3 IS - 12 PY - 1982 SN - 0143-3334 ER - TY - JOUR AB - The binding to DNA of reactive metabolites of trans-7,8-dihydro-7,8-dihydroxybenzo[a]pyrene (BP-7,8-diol) was studied following the incubation of tritiated benzo[a]pyrene (BP) and BP-7,8-diol with nuclei from livers of 3-methylcholanthrene-treated rats. Binding was inhibited to a small extent by glutathione (GSH) alone and to a much greater extent by GSH and cytosol or purified GSH-transferase B and E. In this respect GSH-transferases A and C were also active, but less so. Inhibition of binding of BP-7.8-diol metabolites to DNA mediated by GSH-transferase was associated with the formation of GSH conjugates. The extent of inhibition of binding was similar in incubations of nuclei alone, nuclei and rat liver microsomes, and calf thymus DNA and rat liver microsomes. This indicates that reactive metabolites of BP-7,8-diol, formed either by nuclei or microsomes, are readily accessible to soluble GSH-transferases. GSH and cytosol were also active in inhibiting DNA-binding of reactive metabolites from 9-hydroxybenzo[a]pyrene (9-OH-BP). Thus, in the rat hepatocyte GSH and GSH-transferases may be important in protecting DNA from electrophilic attack by reactive BP-7.8-diol and 9-OH-BP species. AU - Hesse, S. AU - Jernström, B. AU - Martínez, M.A. AU - Moldéus, P.W.* AU - Christodoulides, L.G.* AU - Ketterer, B.* C1 - 41459 C2 - 38581 SP - 757-761 TI - Inactivation of DNA-binding metabolites of benzo[a]pyrene and benzo[a]pyrene-7,8-dihydrodiol by glutathione and glutathione S-transferases. JO - Carcinogenesis VL - 3 IS - 7 PY - 1982 SN - 0143-3334 ER -