Effect of dephosphorylation RB protein expression levels on apoptosis and cell cycle of breast cancer cell line

Objective:To study the effect of RB protein expression levels on apoptosis and cell cycle of breast cancer cell lines. Methods:Human breast cell lines (MCF-7/S) were evaluated. The expressive levels of dephosphorylated RB protein were detected with immunocytochemistry. Apoptosis rates and cell cycle were determined by flow cytometry(FCM). Results: Before treatment of ADR, phosphorylated RB protein was positive in MCF-7/S 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. FCM assays indicated: After 24 hours treatment of 0.25, 2, 5μg/ml ADR ,the rate of MCF-7/S was 17.1%, 18.4%, 25.9% respectively,the apoptotic rate of MCF-7/S was enhanced accordingly. Analysis of the cell cycle made it clear that after treatment of ADR, MCF-7/S cells were accumulated in G_1 phases. Conclusion: There were positive correlation between the expression levels of dephosphorylated RB protein and the apoptosis of MCF-7/S cells, and MCF-7/S was accumulated in G_1 phase of the cell cycle.