ABSTRACT
Purpose:To investigate the relationship between cell apoptosis and dephosphorylated RB protein in human breast cancer. Methods:In our work,human breast cell lines (MCF-7/S,the chemosensitive cell line and MCF-7/ADR,the chemoresistent cell line)were evaluated. Chemosensitivity of two cell lines was evaluated by the MTT colorimetric assay;the expressive levels of dephosphorylated RB protein were detected with immunocytochemistry. Apoptosis rates were determined by flow cytometry(FCM). Results:ADR inhibited proliferation of chemosensitive cell line MCF-7/S ,the 50% inhibition concentration (IC 50 ) was 0.128 ?g/ml;And IC 50 of MCF-7/ADR was 10.89 ?g/ml. The chemotherapeutic sensitivity of MCF-7/S was more than that of MCF-7/ADR by 86 times . Before treatment with ADR,phosphorylated RB protein was positive in two cell lines,but dephosphorylated RB protein was negative;After treatment of different concentration ADR,when the concentration of ADR was increased,expression of dephosphorylated RB protein elevated accordingly in MCF-7/S,but no significant change in MCF-7/ADR. Apoptosis and cell cycle was detected by FCM assays shows ADR induced apoptosis of MCF-7/S more than MCF-7/ADR(P0.05).