The Concomitant Effects of Cis-diamminedichloroplatinum and Caffeine on the Proliferation and Chromosomal Changes

Abstract

The antitumor activity of concomitant Cis-diamminedichloroplatinum (CDDP) and caffeine treatment and its chromosomal effects were studied using by a human gastric cancer cell line, STKM-1. The growth rate was 57% after 3 hours of treatment with CDDP (2 μg/ml), but it was reduced to 23% and 9.3% respectively by incubation with 1 mM and 2 mM caffeine following treatment with CDDP. Thus, the antitumor effect of CDDP was enhanced by caffeine. The incidence of gaps or breaks in the chromosomes after treatment with CDDP (2 μg/ml) was 1.816±1.509/cell and the incidence of exchange was 0.184±0.565/cell. When the cells were incubated with 1 mM caffeine for 24 hours beginning just after CDDP treatment, the incidence of gaps or breaks increased to 4.206±3.162/cell and that of exchanges to 0.760±0.938/cell. The same results were obtained by incubation with caffeine for either 24 or 48 hours after CDDP treatment. These findings indicate that caffeine may inhibit DNA repair, and should enhance antitumor activity when used concomitantly with CDDP in the treatment of gastric cancer.