Zelldifferenzierung und Apoptose bei kultivierten Zellen von soliden Mäusetumoren
With the heterogenity of subpopulations of two mouse tumors in mind, this thesis demonstrates the relations between the differentiation drift of these cells and apoptosis. In this connection it is important to keep in mind that cytokines have capacity to up-regulate neoplastic cells in differentiation and finally lead to cell death. To come to these findings, two mouse tumors that got over the allotransplant- barrier and did not have any H2 antigen presentation on their surface were examined. After adding miscellaneous cytokines (Gm-CSF, SCF, TNF-Alpha, Interferon-Gamma, Interleukin-2) these mouse cell lines were cultivated over nearly 50 passages in vitro. By analyzing the cells with the help of cytometry assays it was possible to show that several kinds of differentiation phases present a correlation between the rate of apoptosis: The Up-grading of the differentiation of the individual cell surface antigens caused an increase of the apoptosis in terms of the physiological control of the cell cycle. However, the highest rates of apoptosis were ascertained while maintaining medium expression. The survey conducted the findings, that there was never a complete loss of cell culture. The reason for that was the presence of a kind of regeneration-pool for a couple of „silent cells”, that kept up the differentiation of the cell clone. These „silent cells” provide the tumor cell population with a constant supply of „new cells”-in vitro they obviously act as a kind of steam cell of this population. To simulate the environment of tumors cytokines were added, nevertheless, the study being an in vitro study, the observations can only be transferred in a modified form to the behavior of tumors in human beings. On the other hand cytokines are definitely able to regulate differentiation and therefore effectuate rising aopotosis. The intended purpose of a total tumor eradication by forced differentiation and apoptosis has not been reached by now. The distinct heterogenity of tumor cells could be the reason for this failed attempt of tumor eradication. The existence of the so called „silent cells” which show no signs of differentiation - similar to the results of this study - present a plausible explanation for the phenomena.
info:eu-repo/classification/ddc/610, Medizin, Apoptose, Heterogenität
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