AIM:To investigate the mechanism by which miR-204-3p inhibits the growth of hepatocellular carcinoma(hCC)tumor endothelial cells(TECs).METHODS:Flow cytometry was used to identify hCCTECs and analyze their purity.Differentially expressed miRNAs in hCC TECs as compared to normal hepatic sinusoidal endothelial cells(hSECs)were examined using the hmiOA v4 human miRNA OneArray?microarray.miR-204-3p showed the most significant decrease in expression and was further studied.Over-expression of miR-204-3p was achieved using lentiviral transduction into TECs of hCC.The biological changes in hCC TECs before and after transduction were detected using MTT and apoptosis assays.The association between miR-204-3p and fibronectin 1(FN1)was determined using the dual luciferase activity assay.Changes in FN1protein expression before and after transduction were detected using Western blot analysis.RESULTS:Microarray results showed that compared to normal hSECs,15 miRNAs were differentially expressed in hCC TECs,including 6 miRNAs with increased expression and 9 miRNAs with decreased expression.Among them,miR-204-3p showed the most significant decrease in expression(log2=-1.233477,P=0.000307).Over-expression of miR-204-3p in hCC TECs via lentiviral transduction significantly inhibited the proliferation of hCC TECs and promoted apoptosis.Results from the dual luciferase activity experiment showed that the luciferase intensity in the wild type FN1 group was significantly inhibited(P<0.05),while that in the mutant FN1 group was not obviously affected.This observation indicated that FN1 was one of the potential targets of miR-204-3p.After over-expression of miR-204-3p in hCC TECs,Western blot analysis showed that the expression of FN1 protein was significantly inhibited.CONCLUSION:MiR-204-3p acts on its potential target gene,FN1,and inhibits its expression,thus blocking the adhesion function of FN1 in promoting the growth of TECs. To investigate the mechanism by which miR-204-3p inhibits the growth of hepatocellular carcinoma (hCC) tumor endothelial cells (TECs). METHODS: Flow cytometry was used to identify hCCTECs and analyze their pure. Differentially expressed miRNAs in hCC TECs as compared to normal hepatic sinusoidal endothelial cells (hSECs) were examined using the hmiOA v4 human miRNA OneArray® microarray.miR-204-3p showed the most significant decrease in expression and was studied again. Over-expression of miR-204-3p was achieved using lentiviral transduction into TECs of hCC. The biological changes in hCC TECs before and after transduction were detected using MTT and apoptosis assays. The association between miR-204-3p and fibronectin 1 (FN1) was determined using the dual luciferase activity assay. Change in FN1protein expression before and after transduction were detected using Western blot analysis .RESULTS: Microarray results showed that compared to normal hSECs, 15 miRNAs were differentially expressed in hCC TECs, including 6 miRNAs with increased expression and 9 miRNAs with decreased expression. Amm them, miR-204-3p showed the most significant decrease in expression (log2 = -1.233477, P = 0.000307) .Over-expression of miR- 204-3p In hCC TECs via lentiviral transduction significantly inhibited the proliferation of hCC TECs and promoted apoptosis. Results from the dual luciferase activity experiment showed that the luciferase intensity in the wild type FN1 group was significantly inhibited (P <0.05), while that in the mutant FN1 group was not apparent affected. This observation indicated that FN1 was one of the potential targets of miR-204-3p. After over-expression of miR-204-3p in hCC TECs, Western blot analysis showed that the expression of FN1 protein was inhibited. CONCLUSION: MiR-204-3p acts on its potential target gene, FN1, and inhibits its expression, thus blocking the adhesion function of FN1 in promoting the growth of TECs.