Metformin and the mTOR inhibitor everolimus (RAD001) sensitize breast cancer cells to the cytotoxic effect of chemotherapeutic drugs in vitro.

作者：Hongyu Liu, Christian Schölz, Chuanbing Zang, Jan H. Schefe, Piet Habbel, Anne C. Regierer, Carsten‐Oliver Schulz, Kurt Possinger, Jan Eucker · 发表于：PubMed · 年份：2012 · 被引用次数：101 · 研究领域：Metabolism, Diabetes, and Cancer、PI3K/AKT/mTOR signaling in cancer、Flavonoids in Medical Research

AIM: Metformin appears to interfere directly with cell proliferation and apoptosis in cancer cells in a non-insulin-mediated manner. One of the key mechanisms of metformin's action is the activation of adenosine monophosphate activated protein kinase (AMPK). AMPK is linked with the phosphatidylinositol 3-kinase (PI3K)/ phosphatase and tensin homolog (PTEN)/protein kinase B (AKT) pathway and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinases (ERK) cascades--all known for being frequently dysregulated in breast cancer. Therefore, simultaneously targeting AMPK through metformin and the PI3K/AKT/mTOR pathway by an mTOR inhibitor could become a therapeutic approach. The aim of this study was to evaluate the anticancer effect of metformin alone and in combination with chemotherapeutic drugs and the mTOR inhibitor RAD001. MATERIALS AND METHODS: The proliferation of breast cancer cells was measured with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; and the cell apoptosis with enzyme-linked immunosorbent assay (ELISA). Gene expression at the protein level was determined by western blot. RESULTS: We tested metformin alone and in combination with RAD001 and/or chemotherapeutic agents (carboplatin, paclitaxel and doxorubicin, respectively) on several human breast cancer cell lines with respect to cell proliferation, apoptosis and autophagy. Metformin alone inhibited cell proliferation and induced apoptosis in different breast ca...