ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of mTOR signal transduction pathway and down-regulating anti-oncogene PTEN on the growth of breast cancer MCF-7 cells.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>