Metformin synergizes with rapamycin to inhibit the growth of pancreatic cancer in vitro and in vivo.

Previous studies have suggested that metformin may improve the survival rate of patients with pancreatic cancer (PC) by regulating the adenosine monophosphate-activated protein kinase/mammalian target of rapamycin (mTOR) signaling pathway. Rapamycin specifically targets mTOR. In the present study, the efficacy of metformin and rapamycin in isolation and combination were investigated for the treatment of PC. The efficacy of metformin and rapamycin in reducing the proliferation of PC cell line SW1990 in vitro and in vivo was evaluated. It was revealed that metformin (10 mmol/l) + rapamycin (2 ng/ml), metformin (15 mmol/l) + rapamycin (20 ng/ml) and metformin (20 mmol/l) + rapamycin (200 ng/ml) significantly inhibited the viability of PC cells compared with untreated cells. Additionally, metformin (20 mmol/l) + rapamycin (200 ng/ml) significantly suppressed the expression of phosphorylated mTOR compared with metformin or rapamycin alone. Using a xenograft tumor model, it was revealed that combination treatment significantly inhibited the growth of PC cells compared with monotherapy. The present study revealed that a combination of metformin and rapamycin synergistically inhibited the growth of PC in vitro and in vivo and may be a potential treatment option for patients with PC.