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Contribution to the study of the Ehrlich-ascites tumor cells

1971; Pergamon Press; Volume: 7; Issue: 5 Linguagem: Inglês

10.1016/0014-2964(71)90042-9

1879-2995

R Bassleer, Claude Desaive,

Cancer and biochemical research

Three Ehrlich-ascites cell lines propagated in vivo have been studied by cytological and quantitative cytochemical methods. These lines are hyperdiploid (45 chromosomes), hypotetraploid (77 chromosomes) or hyperteiraploid (90 chromosomes). They contain marker chromosomes; in each line some of the cells are polyploid (double number of chromosomes). The line with 77 chromosomes is tetraploid as far as the DNA are concerned. The latter have been measured by cytophotometry after Feulgen reaction. The volume of these cells is about 1600 μ3, as measured with an electronic counter. The line with 45 chromosomes (ELD) and the line with 90 chromosomes (ELT) contain a diploid or a tetraploid amount of DNA respectively. For ELD, the modal cell volume is about 880 μ3; for ELT, it is about 1600 μ3. In these tumor cells, the behaviour of DNA during the preparation for mitosis and during mitosis is identical to that observed in normal (non-tumor) cells. Mice which had received hypo- or hypertetraploid Ehrlich cells intraperitoneally have been treated by an alkylating agent, sarcolysine. This antimitotic agent inhibits cell multiplication by blocking the cells in preprophase (post-S or G2); sometimes, the tumor is killed. However, this blockage is reversible under some experimental conditions. In cells blocked in preprophase, the DNA content and the volume are doubled. Later on these cells are able to divide again; then, the DNA content and the volume are normal. Sometimes the cell volume is 8 times higher than in controls though the cells are blocked in preprophase; these cells probably degenerate. The electronic Coulter Counter is very useful to analyze cell populations. However, the results can be interpreted with precision only if the same populations are studied also by cytophotometry. So it is possible to relate the volume variations to the cell cycle. Sarcolysine, as other alkylating agents do, can induce chromosome alterations and abnormal mitoses. The effects of this agent in Ehrlich cells are identical to those produced in normal fibroblasts. Nevertheless, our conclusions concerning the mode of action of sarcolysine could be useful to those who use alkylating agents in cancer chemotherapy.