RESUMO
R 5 was administered in vitro to observe its antitumor activity in human breast carcinoma cell line MCF 7. As the most useful and efficient anthracycline, epirubicin(EPI) was served as the positive chemical treatment control. MTT colorimetric assay was applied to detect cytotoxicity of R 5 to MCF 7 cells. Apoptotic rate of cells double marked with Annexin V FITC and PI was examined by flow cytometry. And, the alteration of wild type (WT) p53, bax and bcl 2 proteins expression was also observed. Ultrastructural change of MCF 7 cells was observed under a transmission electron microscope. The results showed that growth restrain was observed in MCF 7 cells when administered with different doses of R 5 or EPI. The effect was increased concomitantly with the increasing of R 5 or EPI concentration and culture time. Apoptosis was observed since 6 hours after the MCF 7 cells cultured with R 5 or EPI, and the effect was increased with the culture time extending and reached the highest peak at about 48 hours. However, the apoptotic rate decreased when cultured for 72 hours. Different doses of R 5 and EPI can all induce apoptosis in MCF 7 cell, and the apoptotic rate increased with their concentration, but decreased when the concentration was higher than 5?10 -6 mol/L. Ultrastructure of apoptotic MCF 7 cells, observed by transmission electron microscope, showed typical morphologic changes of apoptosis.