Flow microfluorometric analysis of human lymphoid cells exposed to cytostatic concentrations of podophyllotoxin (0.01-10μg per 24 hr) shows that a major part of this population has the G2M DNA content and about 60% of these cells are arrested in mitosis. Although a similar pattern of DNA distribution is seen in cultures exposed to cytostatic concentrations of VM26 (0.01μg) and VP16 (0.1μg) no mitotic cells are seen in these cultures. Exposure to higher concentrations of VM26 (0.1μg) and VP16 (1.0 μg) inhibits the cell cycle traverse and after 24 hr of exposure a major part of the population is arrested with the DNA content of cells in the S part of the cell cycle. Exposure to higher concentrations leads to a reduction in the number of cells with G2M DNA content and a corresponding increase in the number of cells with G1 DNA content. Whereas the cell cycle block induced by podophyllotoxin is readily reversible by reincubation of cells in drug free medium, cells blocked by VM26 and VP16 are unable to resume the cell cycle traverse under similar conditions.
|Title of host publication||Proceedings of the American Association for Cancer Research|
|State||Published - Dec 1 1975|
ASJC Scopus subject areas