Expression of mTOR and its inhibitory effect on cell proliferation and apoptosis of breast cancer cells

Abstract

The aim of this study is to investigate the expression of mTOR in breast cancer and observe the effect of CCI-779 on proliferation and apoptosis of MDA-MB-231 cells. Immunohistochemical staining was used to detect the expression of mTOR protein in breast cancer tissues and MDA-MB-231 cells. MTT assay was used to assess the effect of CCI-779 on proliferation of MDA-MB-231 cells. Annex-inV-FITC/ PI assay was utilized to evaluate the effect of CCI-779 on apoptosis of MDA-MB-231 cells. Among the 71 cases of breast cancer tissues, 54.9% were mTOR-positive that exhibited significantly higher expression than the 32 cases of normal tissues (21.9%); mTOR protein was also found to be expressed in MDA-MB-231 cells. The mTOR inhibitor CCI-779 significantly inhibited the proliferation of MDA-MB-231 cells that was dose- and time-dependent. However, CCI-779 was unable to induce apoptosis of MDA-MB-231 cells as demonstrated with AnnexinV-FITC/PI assay. mTOR plays a key role in the initiation and development of breast cancer, and its inhibitor CCI-779 exerts a strong suppressive activity against MDA-MB-231 cells, suggesting its therapeutic potential to treat breast cancer