Abstract: ObjectiveTo investigate the role and possible molecular mechanism of miRNA26b （miR26b） in the regulation of autophagy in hepatocellular carcinoma cells. 
MethodsThe expression of miRNA26b in human normal liver cell line HL7702 and human hepatoma cell lines HepG2， Hep3B， Bel7402 and SSMC7721 was detected by fluorescence quantitative PCR （QPCR）. Dual luciferase reporter assay was used to evaluate the regulatory effect of miR26b on IL6. MiR26b mimics （transfected group） and negative control NC （negative control group） were transfected into HepG2 cells， and Western blotting was used to detect the expression of IL6／STAT3 signaling pathway and autophagy related protein in two groups. IL6 siRNA1 and IL6 siRNA2 were transfected into HepG2 cells and Western blotting was used to detect STAT3 activation and autophagy related protein expression after interfering IL6. 
ResultsThe expression levels of miR26b in HepG2， Hep3B and Bel7402 cell lines were 034±0063， 069±0092， 057±0086， which was significantly lower than that of normal liver cell line HL7702 （115±0189）， and the difference was statistically significant （P＜005）. MiR26b inhibited the luciferase activity of wildtype IL6 3’UTR reporter gene vector， but had no effect on the luciferase activity of mutant IL6 3’ UTRMUT. After transfection of miR26b mimics， the relative expression of IL6 and pSTAT3 decreased significantly （P＜005）， and the relative expression of autophagy related protein Beclin1 and the ratio of LC3 II／LC3 I increased significantly （P＜005）. After the silence IL6 expression， the relative expression of pSTAT3 decreased significantly （P＜005）， and the relative expression of autophagy related protein Beclin1 and the ratio of LC3 II／LC3 I increased significantly （P＜005）. 
ConclusionMiRNA26b can inhibit the activation of IL6／STAT3 signaling pathway and induce autophagy in hepatoma cells.

Key words: Hepatocellular carcinoma, miRNA26b, IL6／STAT3, Autophagy