PTEN inhibits cell growth and increases chemosensitivity to doxorubicin of human breast cancer cells

Objective To study whether transient overexpression of tumor suppressor gene PTEN could lead to growth suppression and up-regulate the sensitivity to doxorubicin of human breast cancer MCF-7 cells. Methods The eukaryotic expression plasmid pEGFP-C 1-PTEN containing whole cDNA of PTEN was constructed and transfected into MCF-7 cells by Lipofectamine 2000 in vitro. Growth inhibition of the cells was observed by phase contrast microscope and flow cytometry. The clonogenic cell survival ability was studied by clony forming assay. MCF-7 cells′ chemosensitivity to adriamycin was studied with MTT assay. Results PTEN overexpression led to morphological changes characteristic of apoptosis of MCF-7 cells. PTEN overexpression also resulted in a significant increase in G 0/G 1 cell population (14.79%) and apoptosis (10.60%) detected by flow cytometry. The clonogenic survival rate of cells transfected with PTEN was significantly decreased after doxorubicin treatment compared with control. The transfected cells were more sensitive to doxorubicin compared with the control cells ( χ 2=8.59 , P 0.05), and the IC 50 decreased by 1/2 of that of the vector control ( t=4.77, P 0.01). Conclusion Overexpression of PTEN induces apoptosis and G 1 arrest and also increases the chemosensitivity to doxorubicin in human breast cancer MCF-7 cells.