TY - JOUR AB - Exosomes, small extracellular vesicles ranging from 30 to 150 nm, are secreted by various cell types, including tumour cells. Recently, microRNAs (miRNAs) were identified to be encapsulated and hence protected from degradation within exosomes. These exosomal miRNAs can be horizontally transferred to target cells, in which they subsequently modulate biological processes. Increasing evidence indicates that exosomal miRNAs play a critical role in modifying the microenvironment of lung cancers, possibly facilitating progression, invasion, angiogenesis, metastasis and drug resistance. In this review, we summarize the novel findings on exosomal miRNA functions during lung cancer initiation and progression. In addition, we highlight their potential role and challenges as biomarkers in lung cancer diagnosis, prognosis and drug resistance and as therapeutic agents. AU - Hu, C.* AU - Meiners, S. AU - Lukas, C. AU - Stathopoulos, G.T. AU - Chen, J.* C1 - 59084 C2 - 48540 CY - 111 River St, Hoboken 07030-5774, Nj Usa TI - Role of exosomal microRNAs in lung cancer biology and clinical applications. JO - Cell Prolif. VL - 53 IS - 6 PB - Wiley PY - 2020 SN - 0008-8730 ER - TY - JOUR AB - In a micro long-term bone marrow culture (LTBMC) system the effects of irradiation on confluent stromal cell layers were studied. In order to individually analyse the number of granulocyte-macrophage colony-forming cells (GM-CFC) per LTBMC a miniaturized human GM-CFC assay was established. The normalized GM-CFC numbers in the micro-assay compared well with data by the conventional GM-CFC assay. Pre-formed stromal cell layers were irradiated with doses up to 20 Gy and subsequently recharged with allogeneic bone marrow cells (BMC). Immediately before recharge the BMC were stromal cell-depleted by nylon wool filtration. When stromal cell-depleted BMC were inoculated on empty culture dishes, in vitro haemopoiesis rapidly declined. Sustained GM-CFC production, however, was seen when these cells were used as a second inoculum. It is concluded that irradiation doses of up to 20 Gy do not cause alteration of the haemopoietic inductive capacity of confluent stromal cell layers. AU - Brühl, P. AU - Mergenthaler, H.-G. AU - Dörmer, P. C1 - 17800 C2 - 10713 SP - 411-417 TI - Haemopoietic Inductive Capacity of Irradiated Stromal Cell Layers in Human Micro Long-Term Bone Marrow Cultures. JO - Cell Prolif. VL - 21 PY - 1989 SN - 0008-8730 ER - TY - JOUR AB - In a micro long-term bone marrow culture (LTBMC) system the effects of irradiation on confluent stromal cell layers were studied. In order to individually analyse the number of granulocyte-macrophage colony-forming cells (GM-CFC) per LTBMC a miniaturized human GM-CFC assay was established. the normalized GM-CFC numbers in the micro-assay compared well with data by the conventional GM-CFC assay. Pre-formed stromal cell layers were irradiated with doses up to 20 Gy and subsequently recharged with allogeneic bone marrow cells (BMC). Immediately before recharge the BMC were stromal cell-depleted by nylon wool filtration. When stromal cell-depleted BMC were inoculated on empty culture dishes, in vitro haemopoiesis rapidly declined. Sustained GM-CFC production, however, was seen when these cells were used as a second inoculum. It is concluded that irradiation doses of up to 20 Gy do not cause alteration of the haemopoietic inductive capacity of confluent stromal cell layers. AU - Brühl, P.C. AU - Mergenthaler, H.G. AU - Dörmér, P.G. C1 - 42606 C2 - 34743 SP - 411-417 TI - Haemopoietic inductive capacity of irradiated stromal cell layers in human micro long-term bone marrow cultures. JO - Cell Prolif. VL - 21 IS - 6 PY - 1988 SN - 0008-8730 ER - TY - JOUR AB - Therapy-induced modifications of bone marrow plasma cell kinetics were studied in three patients with myelomatosis. The investigation was performed prior to and 15 d after termination of a course of aggressive chemotherapy. An increase in the labelling index (40-212% of pretreatment values) with a corresponding reduction of Ts (5-34%) was observed in all cases. As a consequence of this combined variation, the fractional turnover rate (which represents the percentage of cells produced per unit time) was the parameter with the highest increment (54-276%). These results indicate that plasma cell recruitment occurs soon after chemotherapy and is characterized by a shorter S phase and a higher number of DNA-synthesizing cells. AU - Ucci, G. AU - Riccardi, A. AU - Dörmer, P. AU - Danova, M. AU - Luoni, R. C1 - 17875 C2 - 10791 SP - 405-409 TI - Early Plasma Cell Recruitment in Multiple Myeloma Following Chemotherapy. JO - Cell Prolif. VL - 21 IS - 6 PY - 1988 SN - 0008-8730 ER - TY - JOUR AB - A human leukaemic cell line (REH) growing in suspension was incubated with cis-platinum, hydroxyurea and mitomycin C at various concentrations causing complete cell-cycle arrest. At different times the cell suspensions were harvested, diluted 1:1 with a buffer solution, stained without further treatment with a mixture of acridine orange (AO) and ethidium bromide (EB) and analysed with a biparametrical flow cytometer. Fluorescent plastic beads were introduced into the suspensions to provide an internal numerical reference for the control of cell loss. The fluorescence distributions showed three groups of cells: vital cells (V) which were only stained with AO; dead cells in which EB stained cytoplasmic components but not the nuclear DNA (D1), and dead cells which allowed EB to stain both cytoplasm and nuclear DNA (D2). The kinetics of cells entering D1 depended on drug concentration and showed equal characteristics for cis-platinum and mitomycin, but were different for hydroxyurea. The subsequent entry into D2 occurred about 15 hr later and showed no pronounced dependence on drug concentration. Parallel trypan-blue (TB) exclusion tests revealed that TB only stained D2 cells and therefore is not useful for investigating cell-death kinetics exposure to cell-killing agents. AU - Böhmer, R.M. C1 - 40895 C2 - 40447 SP - 593-600 TI - Two-step cell-death kinetics in vitro during cis-platinum, hydroxyurea and mitomycin incubation. JO - Cell Prolif. VL - 17 IS - 6 PY - 1984 SN - 0008-8730 ER - TY - JOUR AB - Since the classical work on the regulation of canine erythropoiesis by Alpen & Cranmore (1959), it has been generally accepted that recognizable bone-marrow cells are continuously replaced from sources of unrecognizable precursors. Although many features of pluripotent stem cells (PSC) and committed haemopoietic precursors have been determined, direct demonstration of a continuous influx, under normal steady-state conditions, from PSC into the recognizable bone-marrow cell compartments is still lacking. There is abundant evidence that PSC, in a number of species, including primates, resemble atypical or immature (‘transitional’) lumphocytes. By utilizing the technique of quantitative 14C-autoradiography, we have measured the activities of DNA and protein synthesis in individual bone-marrow cells of two healthy humans. A positive relationship was established between the protein synthesis rate and rate of movement through the cell cycle in all proliferative compartments. Lymphoid cells, considered to contain the fraction of PSC, were found in the lower range of this relationship. These low metabolic rates exclude fast growth as well as short cell-cycle times. In view of the low frequency of the potential PSC in the human bone marrow, amounting to less than 2%, these cells cannot be considered to represent a source continuously supplying the pool of rapidly proliferating, recognizable blast cells in the bone marrow under steady-state conditions. Some self-maintenance of a subcompartment within the pool of recognizable normal bone-marrow blast cells is therefore suggested. AU - Dörmér, P.G. AU - Ucci, G. C1 - 41298 C2 - 40445 SP - 367-374 TI - Pluripotent stem cells do not completely maintain normal human steady-state haemopoiesis. JO - Cell Prolif. VL - 17 IS - 4 PY - 1984 SN - 0008-8730 ER - TY - JOUR AB - The generally accepted cell-killing effect of hydroxyurea (HU) on S-phase cells, as well as its potential to arrest cells at the G1/S boundary, hardly explain its benefit for application in human chronic myelogenous leukaemia. Studies were therefore performed in rat haemopoiesis in order to quantify the cell-killing effect on various phases of the cell cycle. For this purpose, the [3H]thymidine ([3H]TdR) labelling index and the specific activity of [3H]TdR in the DNA-synthesizing fraction of cells were determined after a non-cytoreductive dose of 25 mg/kg HU, as well as a medium cytoreductive dose of 100 mg/kg. Furthermore, flow cytometric DNA histograms and absolute as well as differential cell counts of femoral bone marrow were performed after 100 mg/kg HU. The results indicate a predominant cell kill in G1 encompassing almost all 2c cells in the proliferative pool, while the S-phase fraction is not even reduced to half its initial value. The specific activity of [3H]TdR in cell synthesizing DNA, as well as the labelling index after HU show an initial dip and a tendency to recovery, as has been observed in many other cell systems. Instead of a complete restoration, however, there is a second depression of these parameters lasting for at least one cell cycle. The results are interpreted as a partly cell-cycle-dependent and partly independent action of HU in this cell system. The independent component may be attributed to the repeatedly described direct interference of HU with DNA. In rat haemopoiesis, therefore, this direct effect of HU on the DNA strands appears to be much more pronounced than in cell-culture systems and other mammalian tissues. In view of these findings, some caution should be taken in using HU for the determination of the S-phase fraction by way of a suicide experiment. AU - Dörmér, P.G. AU - Böhmer, R.M. C1 - 41450 C2 - 40444 SP - 619-628 TI - Cell-cycle-dependent and -independent damage to rat haemopoiesis by hydroxyurea. JO - Cell Prolif. VL - 17 IS - 6 PY - 1984 SN - 0008-8730 ER - TY - JOUR AB - Ehrlich ascites tumour cells growing in vitro in suspension culture were separated according to volume by the technique of velocity sedimentation in a zonal rotor with a reorienting gradient. Using DNA distribution analysis the sedimentation pattern of the cells could be analysed in detail. With appropriate conditions it was possible to separate pure G1 cells. Samples could also be obtained which were enriched in S or G2 + M cells. The main limitation of the selection in this type of rotor was the reorientation of the gradient which caused disturbances during deceleration of the rotor. The synchronous growth of selected G1 cells has been studied in detail to investigate the reasons for the rather poor synchrony of these cells. The poor synchrony was found to be caused mainly by the small volume of the selected G1 cells compared with the normal volume of G1 cells in an asynchronous population. The synchronization of these cells could be essentially improved by a short treatment with excess thymidine causing a metabolic block at the G1/S border. The duration of this treatment could be minimized using DNA distribution analysis of growing cells after releasing of the block. The durations of the cell cycle phases in synchronized cells agreed with the values calculated in asynchronous cells by DNA distribution analysis and the BrdUrd-Hoechst 33258-technique. AU - Nüsse, M. C1 - 41243 C2 - 40430 SP - 529-543 TI - Synchronization of mammalian cells by selection and additional chemical block studied by DNA distribution analysis and BrdUrd-Hoechst 33258-technique. JO - Cell Prolif. VL - 15 IS - 5 PY - 1982 SN - 0008-8730 ER -