Action of a platinum complex [cis-dichlorobis (cyclopentylamine)-platinum (II)] on Chinese hamster ovary cells in vitro.

cis-Dichlorobis(cyclopentylamine)platinum (II) (DBCP) treatment of Chinese hamster ovary (CHO) monolayer cell cultures was found to cause: (1) growth inhibition due to an impaired G1 leads to S transition and formation of a non-cycling compartment; (2) delayed cell death (with a maximum at 72 h after treatment); (3) decrease of [14C] TdR incorporation into DNA. Part of the surviving cell population was subject to non-lethal damage. The Do values of the dose--survival curves were 9.2 and 14 mug/ml in two kinds of media differing in Na+ and Cl- concentrations. There was no sparing effect of dose fractionation and no cell cycle phase specificity. In the dose range corresponding to the shoulder region of the dose-survival curve,the lethal effect of DBCP treatment was directly related to the decreased rate of DNA synthesis in DBCP-treated cells.