Research On Metformin Influence On Cisplatin Sensitivity On Endometrial Cancer In Vitro

ObjectiveTo explore metformin influence on cisplatin sensitivity and its mechanism in endometrial cancer cell lines.MethodsIshikawa and ECC-1cell lines were used. Cell proliferation was assessed after exposure to metformin alone, metformin and Cisplatin, and Cisplatin alone by MTT. Cell cycle progression and apoptosis were assessed by flow Cytometry. Western Immunobloting was performed to determine the metformin influence on the expression of Akt, p-AKT, m-TOR and p-mTOR in endometrial cancer.Results1. Metformin (5mmol/l) increased cisplatin sensitivity in Ishikawa and ECC1cells. IC50of cisplatin for Ishikawa cell line was (5.11±0.68) μg/ml in the group of cisplatin alone, and (3.12±0.30)μg/ml in group of combined with metformin, respectively. IC50of cisplatin for ECC1cell line was (4.20±0.59) μg/ml in the group of cisplatin alone, and (2.54±0.25)μg/ml in group of combined with metformin, respectively. Statistically significant difference were considered (t=6.343,P=0.024) for Ishikawa cells;(t=4.647,P=0.043) for ECC-1cells. Two cells sensitivity to cisplatin alone and to metformin combination with cisplatin were compared and no statistical significant difference were considered (t=1.753, P=0.154;t=2.595, P=0.06).2. Metformin decreased the expression of p-AKT in both Ishikawa and ECC-1cell lines and considered statistically significance (F=97.121, P＜0.01, F=125.04, P＜0.01). Metformin had no influence on the expression of AKT in Ishikawa and ECC1cells. Metformin decreased the expression of p-mTOR only in Ishikawa cell line and considered statistically significant (F=41.422, P＜0.05). Metformin had no influence on the expression of mTOR in both cell lines and p-mTOR in ECC1cell.3. Metformin (5mmol/l) resulted in G1cell cycle arrest in both the ECC-1and Ishikawa endometrial cell lines. In contrast, cisplatin (1μg/ml) inhibited cell cycle progression through G2arrest in both cell lines. When both metformin and cisplatin were used in combination, the overall effect in both endometrial cancer cell lines was G2cell cycle arrest as opposed to G1arrest.4. Metformin induced apoptosis in endometrial cancer (10.28%and12.62%). The combination of metformin (5mmol/l) and cisplatin (1μg/ml) resulted in increased apoptosis (15.61%and18.24%) compared with cisplatin alone (8.77%and9.44%).Conclusion1. Metformin increase cisplatin sensitivity in endometrial cancer in a ER-independed manner.2.Two potentially mechanisms of metformin influence on cisplatin sensitivity:the one may be mediated through p-AKT and p-mTOR down-regulation in Ishikawa cell and partially through p-AKT down-regulation in ECC1cell, the other may be associated with increasing G2arrest and stimulating cell apoptosis.