The effects of estramustine on metaphase and anaphase in DU 145 prostatic carcinoma cells.

The chemotherapeutic drug, estramustine, has been shown to cause the disassembly of microtubules via binding to microtubule-associated proteins. In this report, estramustine is shown to be a potent inhibitor of mitotic progression in the human prostatic carcinoma cell line, DU 145. Examination of individual living cells via video-enhanced differential interference contrast (DIC) optics shows that the drug delays the onset of anaphase, reduces anaphase spindle-pole elongation (anaphase B), and delays cytokinesis. In addition, immunofluorescent studies demonstrate that estramustine causes a rapid disorganization of the mitotic apparatus at significantly lower concentrations than those reported previously. Electron microscopic studies show that microtubule bundles are present in drug-treated mitotic cells in association with kinetochores and centrioles.