Effects of adriamycin on cell apoptosis and expression of dephosphorylated RB protein in human breast cancer

AIM: To investigate the roles that adriamycin (ADR) plays in the expression of dephosphorylated RB protein and inducing apoptosis of human breast cancer cells (MCF-7/S) cultured in vitro. METHODS: MTT colorimetric assay was applied to examine the growth inhibition,and apoptosis rates (AR) were determined by terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling (TUNEL);the expressive levels of dephosphorylated RB protein were detected with immunocytochemistry. RESULTS: ADR inhibited proliferation of MCF-7/S cells in a dose dependent manner,and the 50% inhibition concentration (IC_ 50 ) was 0.128 mg·L -1 . Tumor cell AR in ADR group (x= 0.261 ) was significantly higher than that in control group (x= 0.045 ,P 0.01 ). The expressive levels of dephosphorylated RB protein in ADR group (MOD×area=987±207) was significantly higher than that in control group (MOD×area=132±32,P 0.01 ). The dephosphorylated RB was enhanced by ADR in breast cancer cells. There was significant positive correlation between AR and the expressive levels of dephosphorylated RB protein in ADR group (P 0.05 ). CONCLUSION: ADR inhibits the growth proliferation and induces apoptosis in MCF-7/S cell line,which is possibly related to enhancing dephosphorylated RB protein expression.