TY  - JOUR
AB  - BACKGROUND: Enteric glial cells (EGCs) have been implicated in colorectal cancer (CRC) progression. This study aimed to develop and validate a prognostic model integrating EGC- and CRC-associated gene expression to predict patient survival, recurrence, metastasis, and therapy response. METHODS: Bulk and single-cell RNA sequencing data were analyzed, and a machine learning-based model was constructed using the RSF random forest algorithm. The model's prognostic value was evaluated through survival analysis, pathway enrichment, immune profiling, and therapy response predictions. RESULTS: The model effectively stratified patients into high- and low-risk groups, with high-risk patients exhibiting significantly worse overall survival (OS) and an increased likelihood of recurrence and metastasis. Gene Set Enrichment Analysis (GSEA) identified key pathways associated with tumor progression, immune regulation, and microenvironmental interactions. The model was significantly correlated with immune cell infiltration and chemokine signaling. High-risk patients exhibited reduced immune therapy efficacy and distinct drug sensitivity profiles, suggesting its potential to guide personalized treatment strategies. CONCLUSION: This model serves as a valuable tool for CRC prognosis and treatment stratification, with potential clinical applications pending further validation.
AU  - Wang, Q.*
AU  - Huang, J.*
AU  - Wu, S.*
AU  - Wang, J.
AU  - Yu, T.*
AU  - Wei, W.*
AU  - Yang, T.*
AU  - Wu, X.*
AU  - Zhai, J.*
AU  - Zhang, X.*
C1  - 75476
C2  - 58169
CY  - 525 B Street, Ste 1900, San Diego, Ca 92101-4495 Usa
TI  - Neuro-immuno-stromal context in colorectal cancer: An enteric glial cell-driven prognostic model via machine learning predicts survival, recurrence, and therapy response.
JO  - Exp. Cell Res.
VL  - 452
IS  - 1
PB  - Elsevier Inc
PY  - 2025
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - OBJECTIVE: A wide range of cardiac diseases is associated with inflammation. "Inflamed" heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process. METHODS AND RESULTS: In mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect. CONCLUSION: Activation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.
AU  - Egorov, D.*
AU  - Kopaliani, I.*
AU  - Ameln, A.K.*
AU  - Speier, S.
AU  - Deussen, A.*
C1  - 68879
C2  - 53734
CY  - 525 B Street, Ste 1900, San Diego, Ca 92101-4495 Usa
SP  - 113868
TI  - Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes.
JO  - Exp. Cell Res.
VL  - 434
IS  - 1
PB  - Elsevier Inc
PY  - 2024
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The aorta-gonad-mesonephros region, from which definitive hematopoiesis first arises in midgestation mouse embryos, has intra-aortic hematopoietic clusters (IAHCs) containing hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). We previously reported expression of the transcription factor Sox17 in IAHCs, and overexpression of Sox17 in CD45c-KIT cells comprising IAHCs maintains the formation of cell clusters and their multipotency in vitro over multiple passages. Here, we demonstrate the importance of NOTCH1 in IAHC formation and maintenance of the HSC/HPC phenotype. We further show that Notch1 expression is positively regulated by SOX17 via direct binding to its gene promoter. SOX17 and NOTCH1 were both found to be expressed in vivo in cells of IAHCs by whole mount immunostaining. We found that cells transduced with the active form of NOTCH1 or its downstream target, Hes1, maintained their multipotent colony-forming capacity in semisolid medium. Moreover, cells stimulated by NOTCH1 ligand, Jagged1, or Delta-like protein 1, had the capacity to form multilineage colonies. Conversely, knockdown of Notch1 and Hes1 led to a reduction of their multipotent colony-forming capacity. These results suggest that the Sox17-Notch1-Hes1 pathway is critical for maintaining the undifferentiated state of IAHCs.
AU  - Saito, K.*
AU  - Nobuhisa, I.*
AU  - Harada, K.*
AU  - Takahashi, S.*
AU  - Anani, M.*
AU  - Lickert, H.
AU  - Kanai-Azuma, M.*
AU  - Kanai, Y.*
AU  - Taga, T.*
C1  - 55462
C2  - 46168
SP  - 145-155
TI  - Maintenance of hematopoietic stem and progenitor cells in fetal intra-aortic hematopoietic clusters by the Sox17-Notch1-Hes1 axis.
JO  - Exp. Cell Res.
VL  - 365
IS  - 1
PY  - 2018
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Osteoblasts are adherent cells, and under physiological conditions they attach to both mineralized and non-mineralized osseous surfaces. However, how exactly osteoblasts respond to these different osseous surfaces is largely unknown. Our hypothesis was that the state of matrix mineralization provides a functional signal to osteoblasts. To assess the osteoblast response to mineralized compared to demineralized osseous surfaces, we developed and validated a novel tissue surface model. We demonstrated that with the exception of the absence of mineral, the mineralized and demineralized surfaces were similar in molecular composition as determined, for example, by collagen content and maturity. Subsequently we used the human osteoblastic cell line MG63 in combination with genome-wide gene set enrichment analysis (GSEA) to record and compare the gene expression signatures on mineralized and demineralized surfaces. Assessment of the 5 most significant gene sets showed on mineralized surfaces an enrichment exclusively of genes sets linked to protein synthesis, while on the demineralized surfaces 3 of the 5 enriched gene sets were associated with the matrix. Focusing on these three gene sets, we observed not only the expected structural components of the bone matrix, but also gene products, such as HMCN1 or NID2, that are likely to act as temporal migration guides. Together, these findings suggest that in osteoblasts mineralized and demineralized osseous surfaces favor intracellular protein production and matrix formation, respectively. Further, they demonstrate that the mineralization state of bone independently controls gene expression in osteoblastic cells.
AU  - Wischmann, J.*
AU  - Lenze, F.*
AU  - Thiel, A.*
AU  - Bookbinder, S.*
AU  - Querido, W.*
AU  - Schmidt, O.*
AU  - Burgkart, R.*
AU  - von Eisenhart-Rothe, R.*
AU  - Richter, G.H.S.*
AU  - Pleshko, N.*
AU  - Mayer-Kuckuk, P.
C1  - 54251
C2  - 46189
SP  - 25-34
TI  - Matrix mineralization controls gene expression in osteoblastic cells.
JO  - Exp. Cell Res.
VL  - 372
PY  - 2018
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Exploring the cell biology of hepatocytes in vitro could be a powerful strategy to dissect the molecular mechanisms underlying the structure and function of the liver in vivo. However, this approach relies on appropriate in vitro cell culture systems that can recapitulate the cell biological and metabolic features of the hepatocytes in the liver whilst being accessible to experimental manipulations. Here, we adapted protocols for high-resolution fluorescence microscopy and quantitative image analysis to compare two primary hepatocyte culture systems, monolayer and collagen sandwich, with respect to the distribution of two distinct populations of early endosomes (APPL1 and EEA1-positive), endocytic capacity, metabolic and signaling activities. In addition to the re-acquisition of hepatocellular polarity, primary hepatocytes grown in collagen sandwich but not in monolayer culture recapitulated the apico-basal distribution of EEA1 endosomes observed in liver tissue. We found that such distribution correlated with the organization of the actin cytoskeleton in vitro and, surprisingly, was dependent on the nutritional state in vivo. Hepatocytes in collagen sandwich also exhibited faster kinetics of low-density lipoprotein (LDL) and epidermal growth factor (EGF) internalization, showed improved insulin sensitivity and preserved their ability for glucose production, compared to hepatocytes in monolayer cultures. Although no in vitro culture system can reproduce the exquisite structural features of liver tissue, our data nevertheless highlight the ability of the collagen sandwich system to recapitulate key structural and functional properties of the hepatocytes in the liver and, therefore, support the usage of this system to study aspects of hepatocellular biology in vitro.
AU  - Zeigerer, A.
AU  - Wuttke, A.*
AU  - Marsico, G.*
AU  - Seifert, S.*
AU  - Kalaidzidis, Y.*
AU  - Zerial, M.*
C1  - 50145
C2  - 42033
CY  - San Diego
SP  - 242-252
TI  - Functional properties of hepatocytes in vitro are correlated with cell polarity maintenance.
JO  - Exp. Cell Res.
VL  - 350
IS  - 1
PB  - Elsevier Inc
PY  - 2017
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The release of nucleic acids and derivatives after tissue-injury may affect cellular immune-response. We studied the impact of extracellular ribo-, desoxyribonucleotides and nucleosides on T-cell immunity. Peripheral-blood-mononuclear-cells (PBMCs) or isolated CD3(+)T-cells obtained from 6 healthy donors were stimulated via CD3/CD28 Dynabeads or dendritic cells (DCs) in the presence or absence of pyrimidine-, purine-nucleotides and -nucleosides (range 2-200µM). Addition of deoxy-, guanosine-triphosphate (dGTP, GTP) and guanosine resulted in a partial inhibition of the induced T-cell-proliferation. Adenosine-triphosphate (ATP), adenosine and the pyrimidine-ribo- and -deoxyribonucleotides displayed no inhibitory capacity. Inhibitory effects of dGTP and GTP, but not of guanosine and ATP were culture-media-dependent and could be almost abrogated by use of lymphocyte-culture-media Xvivo15 instead of RPMI with standard-supplementation. In contrast to RPMI, Xvivo15 resulted in a significant down-regulation of the cell-surface-located ectonucleotidases CD39 (Ecto-Apyrase) and CD73 (Ecto-5´-Nucleotidase), critical for the extracellular nucleotides-hydrolysis to nucleosides, explaining the loss of inhibition mediated by dGTP and GTP, but not Guanosine. In line with previous findings ATP was found to exert immunosuppressive effects on T-cell-proliferation. Purine-nucleotides, dGTP and GTP displayed a higher inhibitory capacity, but seem to be strictly dependent on the microenvironmental conditions modulating the responsiveness of the respective T-lymphocytes. Further evaluation of experimental and respective clinical settings should anticipate these findings.
AU  - Weiler, M.*
AU  - Schmetzer, H.
AU  - Braeu, M.
AU  - Buhmann, R.
C1  - 48698
C2  - 41280
CY  - San Diego
SP  - 1-14
TI  - Inhibitory effect of extracellular purine nucleotide and nucleoside concentrations on T cell proliferation.
JO  - Exp. Cell Res.
VL  - 349
IS  - 1
PB  - Elsevier Inc
PY  - 2016
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - PeBoW, a trimeric complex consisting of pescadillo (Pes1), block of proliferation (Bop1), and the WD repeat protein 12 (WDR12), is essential for processing and maturation of mammalian 5.8S and 28S ribosomal RNAs. Applying a mass spectrometric analysis, we identified the DEAD-box helicase DDX27 as stably associated factor of the PeBoW-complex. DDX27 interacts with the PeBoW-complex via an evolutionary conserved FxF motif in the N-terminal domain and is recruited to the nucleolus via its basic C-terminal domain. This recruitment is RNA-dependent and occurs independently of the PeBoW-complex. Interestingly, knockdown of DDX27, but not of Pes1, induces the accumulation of an extended form of the primary 47S rRNA. We conclude that DDX27 can interact specifically with the Pes1 and Bop1 but fulfils critical function(s) for proper 3' end formation of 47S rRNA independently of the PeBoW-complex.
AU  - Kellner, M.
AU  - Rohrmoser, M.
AU  - Forne, I.*
AU  - Voss, K.
AU  - Burger, K.
AU  - Mühl, B.
AU  - Gruber-Eber, A.
AU  - Kremmer, E.
AU  - Imhof, A.*
AU  - Eick, D.
C1  - 44090
C2  - 36878
CY  - San Diego
SP  - 146-159
TI  - DEAD-box helicase DDX27 regulates 3' end formation of ribosomal 47S RNA and stably associates with the PeBoW-complex.
JO  - Exp. Cell Res.
VL  - 334
IS  - 1
PB  - Elsevier Inc
PY  - 2015
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Extensive changes of higher order chromatin arrangements can be observed during prometaphase, terminal cell differentiation and cellular senescence. Experimental systems where major reorganization of nuclear architecture can be induced under defined conditions, may help to better understand the functional implications of such changes. Here, we report on profound chromatin reorganization in fibroblast nuclei by chaetocin, a thiodioxopiperazine metabolite. Chaetocin induces strong condensation of chromosome territories separated by a wide interchromatin space largely void of DNA. Cell viability is maintained irrespective of this peculiar chromatin phenotype. Cell cycle markers, histone signatures, and tests for cellular senescence and for oxidative stress indicate that chaetocin induced chromatin condensation/clustering (CICC) represents a distinct entity among nuclear phenotypes associated with condensed chromatin. The territorial organization of entire chromosomes is maintained in CICC nuclei; however, the conventional nuclear architecture harboring gene-dense chromatin in the nuclear interior and gene-poor chromatin at the nuclear periphery is lost. Instead gene-dense and transcriptionally active chromatin is shifted to the periphery of individual condensed chromosome territories where nascent RNA becomes highly enriched around their outer surface. This chromatin reorganization makes CICC nuclei an attractive model system to study this border zone as a distinct compartment for transcription. Induction of CICC is fully inhibited by thiol-dependent antioxidants, but is not related to the production of reactive oxygen species. Our results suggest that chaetocin functionally impairs the thioredoxin (Trx) system, which is essential for deoxynucleotide synthesis, but in addition involved in a wide range of cellular functions. The mechanisms involved in CICC formation remain to be fully explored.
AU  - Illner, D.*
AU  - Zinner, R.*
AU  - Handtke, V.*
AU  - Rouquette, J.*
AU  - Strickfaden, H.*
AU  - Lanctot, C.*
AU  - Conrad, M.
AU  - Seiler, A.
AU  - Imhof, A.*
AU  - Cremer, T.*
AU  - Cremer, M.*
C1  - 3100
C2  - 27975
SP  - 1662-1680
TI  - Remodeling of nuclear architecture by the thiodioxoxpiperazine metabolite chaetocin.
JO  - Exp. Cell Res.
VL  - 316
IS  - 10
PB  - Elsevier
PY  - 2010
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Plexins serve as receptors for semaphorins and play important roles in the developing nervous system. Plexin-B2 controls decisive developmental programs in the neural tube and cerebellum. However, whether Plexin-B2 also regulates biological functions in adult nonneuronal tissues is unknown. Here we show by two methodologically independent approaches that Plexin-B2 is expressed in discrete cell types of several nonneuronal tissues in the adult mouse. In the vasculature, Plexin-B2 is selectively expressed in functionally specialized endothelial cells. In endocrine organs, Plexin-B2 localizes to the pancreatic islets of Langerhans and to both cortex and medulla of the adrenal gland. Plexin-B2 expression is also detected in certain types of immune and epithelial cells. In addition, we report on a systematic comparison of the expression patterns of Plexin-B2 and its ligand Sema4C, which show complementarity or overlap in some but not all tissues. Furthermore, we demonstrate that Plexin-B2 and its family member Plexin-B1 display largely nonredundant expression patterns. This work establishes Plexin-B2 and Sema4C as potential regulators of the vascular and endocrine system and provides an anatomical basis to understand the biological functions of this ligand-receptor pair.
AU  - Zielonka, M.*
AU  - Xia, J.J.*
AU  - Friedel, R.H.
AU  - Offermanns, S.*
AU  - Worzfeld, T.*
C1  - 393
C2  - 27363
SP  - 2477-2486
TI  - A systematic expression analysis implicates Plexin-B2 and its ligand Sema4C in the regulation of the vascular and endocrine system.
JO  - Exp. Cell Res.
VL  - 316
IS  - 15
PB  - Elsevier
PY  - 2010
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - E-Cadherin-mediated cell-cell adhesion plays a key role in epithelial cell survival and loss of E-cadherin or beta-catenin expression is associated with invasive tumor growth. Somatic E-cadherin mutations have been identified in sporadic diffuse-type gastric carcinoma. Here, we analysed the fate of E-cadherin with an in frame deletion of exon 8 compared to wild-type E-cadherin and the involved signalling events during cisplatin-induced apoptosis. We report that mutant E-cadherin was more readily cleaved during apoptosis than the wild-type form. Also beta-catenin, an important binding partner of E-cadherin, was processed. E-cadherin cleavage resulted in disconnection of the actin cytoskeleton and accumulation of E-cadherin and beta-catenin in the cytoplasm. Inhibitor studies demonstrated that E-cadherin cleavage was caused by a caspase-3-mediated mechanism. We identified the Akt/PKB and the ERK1/2 signalling pathways as important regulators since inhibition resulted in increased E-cadherin cleavage and apoptosis. In summary, we clearly demonstrate that somatic E-cadherin mutations affect apoptosis regulation in that way that they can facilitate the disruption of adherens junctions thereby possibly influencing the response to cisplatin-based chemotherapy. Elucidating the mechanisms that regulate the apoptotic program of tumor cells can contribute to a better understanding of tumor development and potentially be relevant for therapeutic drug design.
AU  - Fuchs, M.*
AU  - Hermannstädter, C.*
AU  - Hutzler, P.
AU  - Häcker, G.*
AU  - Haller, F.*
AU  - Höfler, H.
AU  - Luber, B.*
C1  - 3793
C2  - 25109
SP  - 153-163
TI  - Deletion of exon 8 increases cisplatin-induced E-cadherin cleavage.
JO  - Exp. Cell Res.
VL  - 314
IS  - 1
PB  - Elsevier
PY  - 2008
SN  - 1090-2422
ER  - 

TY  - JOUR
AU  - Lehmann, M.H.
AU  - Walter, C.*
AU  - Ylisastigui, L.*
AU  - Striebel, F.*
AU  - Ovod, V.*
AU  - Geyer, M.*
AU  - Gluckman, J.C.*
AU  - Erfle, V.
C1  - 5114
C2  - 24157
SP  - 3659-3668
TI  - Extracellular HIV-1 Nef increases migration of monocytes.
JO  - Exp. Cell Res.
VL  - 312
PY  - 2006
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Meiosis pairs and segregates homologous chromosomes and thereby forms haploid germ cells to compensate the genome doubling at fertilization. Homologue pairing in many eukaryotic species depends on formation of DNA double strand breaks (DSBs) during early prophase I when telomeres begin to cluster at the nuclear periphery (bouquet stage). By fluorescence in situ hybridization criteria, we observe that mid-preleptotene and bouquet stage frequencies are altered in male mice deficient for proteins required for recombination, ubiquitin conjugation and telomere length control. The generally low frequencies of mid-preleptotene spermatocytes were significantly increased in male mice lacking recombination proteins SPO11, MEI1, MLH1, KU80, ubiquitin conjugating enzyme HR6B, and in mice with only one copy of the telomere length regulator Terf1. The bouquet stage was significantly enriched in Atm-/-, Spo11-/-, Mei1m1Jcs/m1Jcs, Mlh1-/-, Terf1+/- and Hr6b-/- spermatogenesis, but not in mice lacking recombination proteins DMC1 and HOP2, the non-homologous end-joining DNA repair factor KU80 and the ATM downstream effector GADD45a. Mice defective in spermiogenesis (Tnp1-/-, Gmcl1-/-, Asm-/-) showed wild-type mid-preleptotene and bouquet frequencies. A low frequency of bouquet spermatocytes in Spo11-/-Atm-/- spermatogenesis suggests that DSBs contribute to the Atm-/--correlated bouquet stage exit defect. Insignificant changes of bouquet frequencies in mice with defects in early stages of DSB repair (Dmc1-/-, Hop2-/-) suggest that there is an ATM-specific influence on bouquet stage duration. Altogether, it appears that several pathways influence telomere dynamics in mammalian meiosis. © 2006 Elsevier Inc. All rights reserved.
AU  - Liebe, B.*
AU  - Petukhova, G.*
AU  - Barchi, M.*
AU  - Bellani, M.*
AU  - Braselmann, H.
AU  - Nakano, T.*
AU  - Pandita, T.K.*
AU  - Jasin, M.*
AU  - Fornace, A.*
AU  - Meistrich, M.L.*
AU  - Baarends, W.M.*
AU  - Schimenti, J.*
AU  - de Lange, T.*
AU  - Keeney, S.*
AU  - Camerini-Otero, R.D.*
AU  - Scherthan, H.*
C1  - 4856
C2  - 24171
SP  - 3768-3781
TI  - Mutations that affect meiosis in male mice influence the dynamics of the mid-preleptotene and bouquet stages.
JO  - Exp. Cell Res.
VL  - 312
IS  - 19
PY  - 2006
SN  - 1090-2422
ER  - 

TY  - JOUR
AU  - Wolff, H.
AU  - Hadian, K.
AU  - Ziegler, M.
AU  - Weierich, C.*
AU  - Kramer-Hämmerle, S.
AU  - Kleinschmidt, A.
AU  - Erfle, V.
AU  - Brack-Werner, R.
C1  - 1721
C2  - 23467
SP  - 443-456
TI  - Analysis of the influence of subcellular localization of the HIV Rev protein on Rev-dependent gene expression by multi-fluorescence live-cell imaging.
JO  - Exp. Cell Res.
VL  - 312
PY  - 2006
SN  - 1090-2422
ER  - 

TY  - JOUR
AU  - Demart, S.
AU  - Ceccherini-Silberstein, F.
AU  - Schlicht, St.*
AU  - Walcher, S.
AU  - Wolff, H.
AU  - Neumann, M.
AU  - Erfle, V.
AU  - Brack-Werner, R.
C1  - 10181
C2  - 21639
SP  - 484-509
TI  - Analysis of nuclear targeting activities of transport signals in the human immunodeficiency virus Rev protein. 
JO  - Exp. Cell Res.
VL  - 291
PY  - 2003
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Diffuse-type gastric and lobular breast cancers are characterized by frequent mutations in the cell adhesion molecule E-cadherin. Here we report that tumor-associated mutations of E-cadherin enhanced random cell movement of transfected MDA-MB-435S mammary carcinoma cells as compared to wild-type (wt) E-cadherin-expressing cells. The mutations included in frame deletions of exons 8 or 9 and a point mutation in exon 8 which all affect putative calcium-binding sites within the linker region of the second and third extracellular domain. Motility enhancement by mutant E-cadherin was investigated by time-lapse laser scanning microscopy. Increased cell motility stimulated by mutant E-cadherin was influenced by cell–matrix interactions. The motility-increasing activity of mutant E-cadherin was blocked by application of pharmacological inhibitors of epidermal growth factor receptor and phosphatidylinositol (PI) 3-kinase. Investigation of the activation status of PI 3-kinase and the downstream signaling molecules Akt/protein kinase B and MAP kinase p44/42 showed that these kinases are not more strongly activated in mutant E-cadherin-expressing cells than in wt E-cadherin-expressing cells. Instead, the basal level of PI 3-kinase is necessary for mutant E-cadherin-enhanced cell motility. Our data suggest a critical role of E-cadherin mutations for the fine tuning of tumor cell motility.
AU  - Fuchs, M.*
AU  - Hutzler, P.
AU  - Brunner, I.
AU  - Schlegel,*
AU  - Mages, J.
AU  - Reuning, U.*
AU  - Hapke, S.*
AU  - Duyster, J.*
AU  - Hirohashi, S.*
AU  - Genda, T.*
AU  - Sakamoto, M.*
AU  - Überall, F.*
AU  - Höfler, H.
AU  - Becker, K.-H.
AU  - Luber, B.*
C1  - 21953
C2  - 20424
SP  - 129-141
TI  - Motility Enhancement by Tumor-Derived Mutant E-Cadherin is Sensitive to Treatment with Epidermal Growth Factor Receptor and Phosphatidylinositol 3-Kinase Inhibitors.
JO  - Exp. Cell Res.
VL  - 276
IS  - 2
PY  - 2002
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Fragments of cDNA coding for rat, murine, and human sepiapterin reductase (SR) were amplified by PCR via primer positioning close to the reported 3′-end of the coding region in the rat enzyme. They were sequenced and used as probes for mRNA detection. Northern blot analysis detected two mRNA species for SR. Their sizes were 1.3 and 2.1 kb for rat, 1.3 and 2.3 kb for mouse, and 1.6 and 2.1 kb for human cell lines. Comparison of rat cell lines and rat tissues indicated that in tissues only the 1.3-kb species is present. Washing of the Northern blots under different stringency conditions indicated a more stable interaction of the 1.3-kb mRNA species with the cDNA probe as compared to the 2.3-kb species. The 1.3-kb species corresponds to the reported 28.2-kDa molecular mass of rat SR monomer. SR mRNA expression is absent in the human NK-like cell line YT and in the murine erythroleukemia subclone B8/3, which both lack SR activity. Moreover, the relative mRNA expression correlates with the enzymatic activities of different cell lines within the same species. This indicates that SR activity is regulated by its steady state mRNA levels.
AU  - Maier, J.
AU  - Schott, K.
AU  - Werner, T.
AU  - Bacher, A.
AU  - Ziegler, I.
C1  - 20097
C2  - 13272
SP  - 217-222
TI  - Detection of a Noval Sepiapterin Reductase mRNA Assay of mRNA in Various Cells and Tissues of Various Species.
JO  - Exp. Cell Res.
VL  - 204
IS  - 2
PY  - 1993
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Fragments of cDNA coding for rat, murine, and human sepiapterin reductase (SR) were amplified by PCR via primer positioning close to the reported 3'-end of the coding region in the rat enzyme. They were sequenced and used as probes for mRNA detection. Northern blot analysis detected two mRNA species for SR. Their sizes were 1.3 and 2.1 kb for rat, 1.3 and 2.3 kb for mouse, and 1.6 and 2.1 kb for human cell lines. Comparison of rat cell lines and rat tissues indicated that in tissues only the 1.3-kb species is present. Washing of the Northern blots under different stringency conditions indicated a more stable interaction of the 1.3-kb mRNA species with the cDNA probe as compared to the 2.3-kb species. The 1.3-kb species corresponds to the reported 28.2-kDa molecular mass of rat SR monomer. SR mRNA expression is absent in the human NK-like cell line YT and in the murine erythroleukemia subclone B8/3, which both lack SR activity. Moreover,the relative mRNA expression correlates with the enzymatic activities of different cell lines within the same species. This indicates that SR activity is regulated by its steady state mRNA levels.
AU  - Maier, J.
AU  - Schott, K.
AU  - Werner, T.
AU  - Bacher, A.
AU  - Ziegler, I.
C1  - 40412
C2  - 40029
SP  - 217-222
TI  - Detection of a novel sepiapterin reductase mRNA: Assay of mRNA in various cells and tissues of various species.
JO  - Exp. Cell Res.
VL  - 204
IS  - 2
PY  - 1993
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Differentiated murine teratocarcinoma cell lines have been widely used as sources for the basement membrane proteins laminin and collagen IV. In order to understand the control of their expression, we have measured the transcription rates of the corresponding genes in nuclear run-on assays. The ratios of transcripts obtained from the five different genes of interest (for laminins A, B1, and B2 and α1(IV), α2(IV)) are rather different from the ratios of the corresponding mRNAs, which are again different from the protein levels needed. The gene for α2(IV) is transcribed at a higher rate than the one for α1(IV) and, similarly, the gene for laminin A is transcribed at a higher rate than the other two laminin genes, respectively. However, the α2(IV) and laminin A mRNA levels are lower than those for the other chains of the same molecule. The α1(IV) mRNA is 3- to 15-fold more abundant than the α2(IV) mRNA, depending on the cell line. At the protein level, the A chain seems tobe limiting for the assembly of laminin, in accordance with its low mRNA level. The two collagen chains have variable pool sizes, but the triple helical molecules always seem to be composed of two α1(IV) and one α2(IV) chains. These results point to extensive control mechanisms at various stages of post-transcriptional events, some of which we could identify.
AU  - Speth, C.
AU  - Oberbäumer, I.*
C1  - 40449
C2  - 40104
SP  - 302-310
TI  - Expression of basement membrane proteins: Evidence for complex post-transcriptional control mechanisms.
JO  - Exp. Cell Res.
VL  - 204
IS  - 2
PY  - 1993
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - After differentiation induction in HL-60 cells by treatment with retinoic acid, phorbol ester, or dimethyl sulfoxide strong downregulation of the steady state mRNA level of the putative protein No. 3 of the large ribosomal subunit (rpL3) was observed. Downregulation was also observed in other hemopoietic human cell lines, although to a lesser extent. Four ribosomal protein mRNAs were compared in their degree of downregulation after differentiation induction or actinomycin D treatment. The comparatively fast response of rpL3 mRNA observed could indicate a regulatory function of rpL3 protein.
AU  - Mailhammer, R.
AU  - Szöts, H.
AU  - Bönisch, J.
AU  - Dörmér, P.G.
C1  - 40503
C2  - 38715
SP  - 145-148
TI  - Downregulation of messenger RNA levels for ribosomal proteins in differentiating HL-60 cells.
JO  - Exp. Cell Res.
VL  - 200
IS  - 1
PY  - 1992
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The cell-cycle progression of rat thymocytes from G0 through G1 to DNA synthesis is associated with a transient synthesis of H4biopterin, the concentration of which reaches a maximum at the time of S-phase entry and then decreases. This synthesis of H4biopterin is controlled by the specific activity of GTP cyclohydrolase I, which peaks in G1/S cells. In contrast, the catalytic activity of sepiapterin reductase remains constant throughout the cell-cycle. At G0 the steady state mRNA levels specific for GTP cyclohydrolase I and sepiapterin reductase, respectively, are below the limits of detection. Both accumulate as the thymocytes progress through the cell-cycle but lack cyclic down regulation. The data indicate that the variations in H4biopterin synthesis during the cell-cycle are caused by growth regulated increase in GTP cyclohydrolase I mRNA expression, with subsequent post-translational inactivation. This latter is likely due to the degree of enzyme phosphorylation.
AU  - Schott, K.
AU  - Brand, K.A.
AU  - Hatakeyama, K.
AU  - Kagamiyama, H.
AU  - Maier, J.
AU  - Werner, T.
AU  - Ziegler, I.
C1  - 40685
C2  - 38895
SP  - 105-109
TI  - Control of cell-cycle-associated tetrahydrobiopterin synthesis in rat thymocytes.
JO  - Exp. Cell Res.
VL  - 200
IS  - 1
PY  - 1992
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The induction of the enzymes in the tetrahydrobiopterin pathway by dimethyl sulfoxide (DMSO) was investigated in subclones F4N and B8/3 of the proerythroblastoid Friend erythroleukemia cell line (MEL). GTP-cyclohydrolase, the initial enzyme in the biosynthetic pathway, is virtually absent in both clones, but expression increases during 3 days of DMSO treatment. The final enzyme levels show 12-fold (subclone B8/3) and 40-fold (subclone F4N) increases compared to initial values. Enhancement of 6-pyruvoyl tetrahydropterin synthase activity is detectable 6 h after exposure to DMSO and continues to increase in the 3-day time period to 2.4-fold and 1.8-fold levels in subclones B8/3 and F4N, respectively. Sepiapterin reductase is present in unstimulated F4N cells and absent in B8/3 cells. The enzyme activity is not affected by DMSO treatment in either cell line. This explains why DMSO treatment causes accumulation of tetrahydrobiopterin in the MEL subclone F4N, but not in subclone B8/3. MEL cells are devoid of phenylalanine hydroxylase for which tetrahydrobiopterin serves as cofactor. In F4N, but not in B8/3, tetrahydrobiopterin modulates the rate of [3H]-thymidine incorporation, thus being functionally linked with cell proliferation rather than with differentiation. In contrast to T lymphocytes, periods of tetrahydrobiopterin synthesis and of modulator function are uncoupled in MEL cells.
AU  - Kerler, F.
AU  - Ziegler, I.
AU  - Schmid, C.
AU  - Bacher, A.
C1  - 18364
C2  - 11556
SP  - 151-156
TI  - Synthesis of tetrahydrobiopterin in Friend erythroleukemia cells and its modulator effect on cell proliferation.
JO  - Exp. Cell Res.
VL  - 189
IS  - 2
PY  - 1990
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The induction of the enzymes in the tetrahydrobiopterin pathway by dimethyl sulfoxide (DMSO) was investigated in subclones F4N and B8/3 of the proerythroblastoid Friend erythroleukemia cell line (MEL). GTP-cyclohydrolase, the initial enzyme in the biosynthetic pathway, is virtually absent in both clones, but expression increases during 3 days of DMSO treatment. The final enzyme levels show 12-fold (subclone B8/3) and 40-fold (subclone F4N) increases compared to initial values. Enhancement of 6-pyruvoyl tetrahydropterin synthase activity is detectable 6 h after exposure to DMSO and continues to increase in the 3-day time period to 2.4-fold and 1.8-fold levels in subclones B8/3 and F4N, respectively. Sepiapterin reductase is present in unstimulated F4N cells and absent in B8/3 cells. The enzyme activity is not affected by DMSO treatment in either cell line. This explains why DMSO treatment causes accumulation of tetrahydrobiopterin in the MEL subclone F4N, but not in subclone B8/3. MEL cells are devoid of phenylalanine hydroxylase for which tetrahydrobiopterin serves as cofactor. In F4N, but not in B8/3, tetrahydrobiopterin modulates the rate of [3H]-thymidine incorporation, thus being functionally linked with cell proliferation rather than with differentiation. In contrast to T lymphocytes, periods of tetrahydrobiopterin synthesis and of modulator function are uncoupled in MEL cells.
AU  - Kerler, F.
AU  - Ziegler, I.
AU  - Schmid, C.
AU  - Bacher, A.
C1  - 41152
C2  - 36383
SP  - 151-156
TI  - Synthesis of tetrahydrobiopterin in Friend erythroleukemia cells and its modulator effect on cell proliferation.
JO  - Exp. Cell Res.
VL  - 189
IS  - 2
PY  - 1990
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Interleukin 3 (IL-3) stimulates the growth of various types of hemopoietic progenitors. In vitro, survival of a series of murine cell lines derived from either neoplastic or nonneoplastic hemopoietic tissue shows a strict IL-3 dependence. In order to test the implication of energy metabolism in this dependence as claimed in several studies, intracellular ATP levels as well as accumulative lactate release were measured in the murine hemopoietic lines FDC-P1, 32Dcl.23, DA-1, DA-3, NFS-60, and NFS-78. ATP levels showed little or no changes within 4-6 h of IL-3 starvation. In the absence of IL-3 the accumulative lactate release ranged from 1.4 to 2.6 mM, and in its presence values between 1.5 and 3.4 mM were recorded within 7 h. Only 32Dcl.23 showed an almost complete suppression of lactate release upon IL-3 withdrawal. The cell cycle times of these cell lines determined by flow cytometry ranged between 9 (DA-3) and 24 h (NFS-78). In the presence of IL-3 there was a significant inverse relationship between cell cycle times and lactate production. It is concluded that neither ATP generation nor the metabolic pathway of lactate production, although the latter correlated with proliferative activity in the studied cell lines, is controlled by IL-3. Furthermore, no control by IL-3 of essential amino acid incorporation into proteins was detected in cell lines 32Dcl.23 and NFS-60.
AU  - Reisbach, G.
AU  - Ellwart, J.W.
AU  - Dörmér, P.G.
C1  - 33627
C2  - 36407
SP  - 175-178
TI  - Lactate production and amino acid incorporation in interleukin 3-dependent, factor-derived hemopoietic murine cell lines.
JO  - Exp. Cell Res.
VL  - 190
IS  - 2
PY  - 1990
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - The kinetics of unscheduled DNA synthesis in normal human fibroblasts was characterized by flow cytometry utilizing the immunofluorescent detection of 5-bromo-2′-deoxyuridine (BrdUrd) incorporated into cellular DNA during the repair process. Quiescent normal human fibroblasts were irradiated with ultraviolet light and incubated in the presence of BrdUrd during a postirradiation repair period. The amount of unscheduled DNA synthesis was then quantified in the quiescent cells by immunofluorescence staining using monoclonal antibodies against BrdUrd incorporated into the DNA. Significant amounts of unscheduled DNA synthesis were measured after doses as low as 0.1 J/m2 and for time periods as short as 15 min. The initial repair rate was found to be linear with time at all doses tested until repair neared completion. Interestingly, the initial repair rate was constant for doses over the range of 5 to 40 J/m2, whereas the time to completion of repair was dose dependent. These results suggest that above 5 J/m2 in normal human fibroblasts, the repair process is saturated but continues to function until all available regions are repaired. Using this methodology for measuring unscheduled DNA synthesis in combination with second and third flow markers, it is now possible to measure unscheduled DNA synthesis in heterogeneous mixtures of cells.
AU  - Beisker, W.*
AU  - Hittelman, W.N.
C1  - 41216
C2  - 36170
SP  - 156-167
TI  - Measurement of the kinetics of DNA repair synthesis after uv irradiation using immunochemical staining of incorporated 5-bromo-2′-deoxyuridine and flow cytometry.
JO  - Exp. Cell Res.
VL  - 174
IS  - 1
PY  - 1988
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Cultures of the promyelocytic leukemia cell line HL-60 usually contain considerable numbers of spontaneously differentiating cells and are asynchronous in terms of cell-cycle phases. Counterflow centrifugal elutriation studies have been conducted to obtain a homogeneous cell population with regard to cell-cycle phases and stage of differentiation. Despite their small volume and probably because of their high buoyant density, differentiated cells are elutriated predominantly at higher flow rates. Accordingly, G1 cells elutriated at low flow rates are substantially free from spontaneously differentiating cells. By optimizing the technique, a population with approx. 90% G1 cells and less than 1% spontaneously differentiating cells was obtained. The yield in the fractions chosen was 5.1% of all cells recovered from elutriation. In culture, a cell population of this purity maintains a synchronous cell cycle for more than 2 days. This allows an exact determination of the time after induction when first signs of differentiation occur. The presence of 1 μM retinoic acid (RA) causes the first significant increase of NBT-positive cells between the 24th and 27th h of culture.
AU  - Ohmann, J.
AU  - Ellwart, J.W.
C1  - 41586
C2  - 38261
SP  - 524-530
TI  - Simultaneous enrichment of HL-60 cells in G1 and separation from differentiating cells by centrifugal elutriation for studies on differentiation induction.
JO  - Exp. Cell Res.
VL  - 169
IS  - 2
PY  - 1987
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Pteridine levels of interleukin 2 (IL-2) receptor+ T-cell populations have been determined by HPLC after iodine oxidation; neopterin was monitored in the culture supernatants by radio-immunoassay. Upon addition of IL-2, cellular levels of biopterin and 6-hydroxymethylpterin rise transiently from 0.02 to 0.9 pmol/106 cells, cellular levels of neopterin from 1.5 to 4.1 pmol/106 cells. They peak at 8 and 13 h, respectively, after exposure to IL-2. Neopterin is not accumulated in the culture supernatant. DNA synthesis in T cells begins 10-12 h after adding the lymphokine and the portion of cells that undergo S-phase transition gradually increases during the subsequent 10 h. Entry into DNA synthesis phase is markedly accelerated if IL-2 is supplied together with tetrahydrobiopterin (0.8-1.6 x 10-6 M) and the kinetics of entry into the S-phase transition during the period of 6-20 h become linear. This indicates that tetrahydrobiopterin modulation of IL-2 activity (Ziegler, I. et al. Naturwiss 72 (1985) 330) is an early event occurring during IL-2 signal transmission.
AU  - Ziegler, I.
AU  - Schwulera, U.
AU  - Ellwart, J.W.
C1  - 40878
C2  - 36125
SP  - 531-538
TI  - Pteridines are produced during interleukin 2-induced T-cell proliferation and modulate transmission of this signal.
JO  - Exp. Cell Res.
VL  - 167
IS  - 2
PY  - 1986
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Several antibiotics were examined for their potential to eliminate mycoplasmas from contaminated cell cultures. Acholeplasma laidlawii, Mycoplasma arginini, Mycoplasma hyorhinis and Mycoplasma orale were effectively eliminated from experimentally contaminated mouse fibroblasts and mink epithelial cells by the use of the antibiotics minocycline and tiamutin. An elimination procedure was established, which involved the consecutive treatment of the cultures over a period of 3 weeks, followed by cell cloning. This procedure was effective when applied to cell lines which had been contaminated with unidentified and partially non-cultivable strains of mycoplasmas.
AU  - Schmidt, J.
AU  - Erfle, V.F.
C1  - 41686
C2  - 38491
SP  - 565-570
TI  - Elimination of mycoplasmas from cell cultures and establishment of mycoplasma-free cell lines.
JO  - Exp. Cell Res.
VL  - 152
IS  - 2
PY  - 1984
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Cells were exposed to BrdUrd for intervals of between 0 and 3 h, stained with a mixture of 33258 Hoechst and propidium iodide (PI) and analysed in a two-parametrical flow cytometer. The BrdUrd-quenched Hoechst fluorescence gives information about where the cells were located at time 0 of the incubation, and the DNA-specific PI fluorescence gives information about the actual location of the cells in the cycle. Narrow windows in the Hoechst fluorescence were selected. The location of the corresponding cells in the S phase, as determined from the peaks of the projection on the PI-axis, yielded information about how far the cells had travelled through S phase during BrdUrd incubation. Thereby, the DNA synthesis rate in subcompartments of S phase was determined and showed maximum values at approximately mid-S. In addition, information is obtained about the whole duration of the S phase and the spread of transit velocities through subcompartments of S.
AU  - Ellwart, J.W.
AU  - Boehmer, R.M.
AU  - Doermer, P.
C1  - 40914
C2  - 38861
SP  - 111-115
TI  - Rate of DNA synthesis determined by flow cytometry using the BrdUrd/Hoechst technique in combination with propidium-iodide staining.
JO  - Exp. Cell Res.
VL  - 139
IS  - 1
PY  - 1982
SN  - 1090-2422
ER  - 

TY  - JOUR
AB  - Tritiated ribosomal RNA (rRNA) was prepared from the roots of Vicia faba after incubation in 3H uridine. Separation of the nucleic acids MAK chromatography yielded fractions of specific activity of 4-5 x 105 dpm/μg. 4 + 5S, 18S and 25S RNA fractions were used for cytological hybridization on squash preparations of Vicia faba root tip meristems. Autoradiographs of the 18S and 25S RNA preparations exhibited a clear labelling in the secondary constriction of the satellite (SAT) chromosomes after exposition times of 28 weeks.
AU  - Scheuermann, W.
AU  - Knaelmann, M.
C1  - 41527
C2  - 37941
SP  - 463-465
TI  - Localization of ribosomal cistrons in metaphase chromosomes of Vicia faba (L.).
JO  - Exp. Cell Res.
VL  - 90
IS  - 2
PY  - 1975
SN  - 1090-2422
ER  -