The Role And Mechanism Of Metformin Inhibiting Endometrial Cancer In Vitro

Objectives1. To investigate the effect of metformin in inhibiting proliferation of endometrial cancer cell lines (Ishikawa and ECC1) in a dose dependent manner.2. To understand the mechanism of metformin inhibiting proliferation in endometrial cancer.Materials and MethodIshikawa and ECC-1endometrial cancer cell lines were used for this study. Endometrial cancer cell lines were exposed to different doses of metformin of (0.5mmol/1, lmmol/1,5mmol/1,10mmol/1,15mmol/l,20mmol/l,25mmol/l,30mmol/1) for72hrs and the inhibition rate were detected using MTT assay. Western immune blotting was performed to detect GRP78expression in endometrial cancer cell lines after exposure of metformin in the different doses for48hrs. Flow cytometry is used to evaluate the apoptosis induced by metformin in doses for72hours.Result1.Endometrial cancer cell lines exposed to different doses of metformin (0.5mmol/l, lmmol/1,5mmol/l,10mmol/l,15mmol/l,20mmol/l,25mmol/l,30mmol/l) for72hrs were resulted in inhibition of both cancer cell lines, where IC50of Ishikawa and ECC1were (5.25±0.54)mmol/1and (3.28±0.23)mmol/1, respectively. Metformin inhibited proliferation of endometrial cancer cell lines in a dose dependent manner, and it was less sensitivity in Ishikawa cell than that in ECC1cell.2.Metformin decreased GRP78expression in Ishikawa and ECC1cells in dose depended manner. The GRP78expression among the groups of Ishikawa and ECC1were different and were statistically significant (F=675.254, P=0.000, F=356.521, P=0.000), respectively. And also both cell lines were compared with each others in same dose which were shown statistically significant (from control to30mmol/l, t=33.675, P=0.00,t=11.139, P=0.00,t=22.518, P=0.00,t=13.898, P=0.00, t=9.912, P=0.001, t=8.216, P=0.001,t=5.000, P=0.007).3.Cell apoptosis rate for Ishikawa and ECC1treated with different doses of metformin control,0.5mmol/l, lmmol/1,5mmol/l,10mmol/l,20mmol/l,30mmol/l were4.42%, 6.97%,8.04%,10.87%,17.45%48.45%,53.8%and11.69%,20.15%,23.11%,30.32%,35.56%,46.78%,83%, respectively. Cell apoptosis rate was higher in ECC1cell than in Ishikawa cell.Conclusion1. Metformin inhibits proliferation of both endometrial cancer cell lines in a dose dependent manner.2. The mechanism for metformin inhibiting proliferation in endometrial cancer was associated with down-regulation of GRP78expression and induction of apoptosis.