Abstract: Objective To investigate the effect of mTOR signal transduction pathway and down-regulating anti-oncogene PTEN
on the growth of breast cancer MCF-7 cells. Methods MCF-7 cells were transfected with the eukaryotic expression plasmid
pcDNA3.1-mTOR and non-loaded plasmid, and the expression of mTOR in the cells was detected using Western blotting. Flow
cytometry was used to analyze apoptosis and cell cycle of the transfected cells, and the expression of PTEN was detected after
transfection. Results The cells transfected with pcDNA3.1-mTOR showed a increased growth rate than those transfected with
the non-loaded plasmid and those without transfection. The expression of the protein PTEN decreased obviously in the cells
after mTOR trasnfection. Conclusion mTOR can regulate the expression of PTEN via PI3K/AKT/PTEN pathways through a
negative feedback mechanism. Increased mTOR expression promotes MCF-7 cell growth, suggesting the potential value of
mTOR specific inhibitor in the treatment of breast cancer.