Effects of platinum-thymine on mitosis of sarcoma-180 ascites cells in vitro: ultrastructural study.

Electron microscopic studies of sarcoma-180 ascites cells, which were treated with platinum-thymine at a concentration of 60 micrograms/ml, showed mitotic inhibition. The drug clumped the chromosomes into a compact mass at the center of the cell preventing them from separating during mitosis. Prolonged treatment depolymerized spindle fibers and cytoplasmic microfilament. Degraded cytoplasmic organelles crowded around the clumped chromosomes. Disintegrating and casting off of cortical cytoplasm was apparent. Platinum-thymine-treated cells did not resume mitosis irrespective of the amount of time they were allowed to remain in fresh medium. Perturbation of mitotic machinery by platinum-thymine inhibited the mitotic process and caused eventual demise of the cancer cells.