[Effect of etoposide and amsacrine on mitotic progression of GM-130 and Hep-2 cell lines. The flow cytometry assay].

It has been shown that inhibitors of topoisomerase II (topo II) etoposide and amsacrine results in accumulation of GM-130 and Hep-2 cells with 4c DNA amount. The differential analysis based on flow cytometry (Zenin et al., 2001) and enabled us to discriminate cells with 4c DNA--G2, M, including metaphase and anaphase cells and cells in pseudo-G1. 1 microM etoposide evoked cell accumulation in G2 phase, while 40 microM etoposide blocked cell proliferation, which was confirmed by a complete absence of both mitotic cells and 4c DNA cell accumulation. GM-130 and Hep-2 cells that were first blocked and then washed from nocodazole, and after that treated with 50 microM etoposide or 20 microM amsacrine, were shown to enter pseudo-G1 with 4c DNA amount per cell. In the presence of nocodazole, 4 and 40 microM amsacrine evoked transition of all mitotic cells to pseudo-G1 within 1 h. 15 or 30 minutes pulse treatments of GM-130 cells with 40 microM amsacrine in the presence of nocodazole, followed by incubation in drug-free medium, resulted in the similar transition of cells to pseudo-G1.