[The role of mir-221/222 in inhibiting endoplasmic reticulum stress-induced human hepatocarcinoma cell apoptosis].

Objective: To investigate the role of miR-221/222 in inhibiting endoplasmic reticulum stress-induced human hepatocarcinoma cells apoptosis.

Method: miR-221/222 mimics and inhibitors were used to mimic or block the function of endogenous miR-221/222 respectively. Western blot and flow cytometry were used to test the effects of miR-221/222 on cell cycle and apoptosis under endoplasmic reticulum stress in human hepatocellular carcinoma cells.

Results: Endoplasmic reticulum stress resulted in miR-221/222 down-regulation in human hepatocellular carcinoma cells. miR-221/222 mimics and inhibitors inhibited and promoted respectively endoplasmic reticulum stress-mediated p27Kip1 induction. Moreover, p27Kip1 suppression not only resulted in reduction in the fraction of G1 phase cells, but also promoted the endoplasmic reticulum stress-mediated apoptosis in human hepatocellular carcinoma cells.

Conclusion: miR-221/222 were downregulated by endoplasmic reticulum stress in human hepatocellular carcinoma cells, which subsequently protected human hepatocellular carcinoma cells against endoplasmic reticulum stress-induced apoptosis through p27Kip1 regulation.