Abstract: Objective To explore the inhibitory effect on hepatocellular carcinoma growth by microRNA194 overexpression in Balb/c nude mice,and the possible mechanism by which the microRNA194 works. Methods We constructed the hepatoma cell Hep3B with microRNA194 overexpression by cell transfection and the cells were subcutaneously inoculated into Balb/c nude mice. Then,the microRNA194 overexpression was verified in Hep3B cells and in the tumor tissues by real-time fluorescent quantitative PCR. Thirty Balb/c nude mice were randomly assigned to the microRNA194 overexpression group （n=15） and the control group （n=15）. The tumor volume was measured every 5 days and the tumor weight was measured at 21 days post-inoculation. Finally,real-time fluorescent quantitative PCR and Western bolt were performed to detect insulin-like growth factor 1 receptor （IGF1R） mRNA levels and its protein expression respectively. Results The microRNA194 levels in Hep3B cells and in tumor tissues with microRNA194 overexpression were （2.68±0.33） and （2.33±0.38）,much higher than in the control group【（1.00±0.12） and（1.00±0.16）,respectively,P<0.01】;At day 11,day 16 and day 21 post-inoculation,the tumor volume in the microRNA194 overexpression group were （0.25±0.08）,（0.31±0.11） and （0.46±0.10） mm³,much lower than in the control group 【（0.56±0.13）,（0.73±0.20） and （0.95±0.22） mm³,P<0.01】;At day 21 post-inoculation,the tumor weight in the microRNA194 overexpression group was （0.85±0.19） g,much lower than in the control group【（1.43±0.27） g,P<0.01】;the mRNA level and its protein expression of IGF1R in the microRNA194 overexpression group were（0.78±0.12） and （0.81±0.17）, much lower than in the control group 【（1.0±0.16） and （1.0±0.11）,P<0.01】. Conclusion The overexpression of microRNA194 might inhibit tumor growth by suppressing the expression of IGF1R, which needs further investigation.

Key words: Hepatocellular carcinoma, microRNA194, Insulin-like growth factor 1 receptor, Balb/c nude mice