The effects of epirubicin and tamoxifen on H- thymidine labelling index in estrogen - receptor - positive Ehrlich ascites tumor cells growing in vivo

The combined effect of Epirubicin (EPI) and Tamoxifen (TAM) on growth kinetics of Ehrlich Ascites Tumor cells (EAT) was investigated in vivo. In the present study, an estrogen receptor positive ER (+) hyper diploid cell lines were studied. Optimum doses of EPI and TAM (110mg and 20mg, respectively) were used. Cells were treated with these doses for 5 and 9 days. The proliferation of EAT cells growing in vivo is inhibited by EPI and TAM concentrations. The results showed that combination of EPI with TAM decreased the H-thymidine labeling index more effectively than did either drug alone (p<0.05). EPI+TAM treatment’s showed a maximum synergistic effect on day 5 and 9, thus inhibition of DNA synthesis was not changed by days. As a result, day factor is eliminated in combined treatment is the most important result of our study.