Expression of long non-coding RNA LINC00665 in hepatocellular carcinoma and its effect on angiogenesis and mechanism / 中华肝胆外科杂志

ABSTRACT

Objective:To investigate the expression of long non-coding RNA 00665 (LINC00665) in hepatocellular carcinoma (HCC) and its regulatory effect on angiogenesis of hepatocellular carcinoma cells and its potential molecular mechanism.Methods:HCC tissues and corresponding paracancerous tissues of 100 patients with HCC in the First Affiliated Hospital of Nanjing Medical University from May 2016 to April 2017 were collected, and the survival prognosis was compared. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of LINC00665 in HCC tissues and cells. The effect of LINC00665 overexpressed Hep-3B cells on the angiogenesis of human umbilical vein endothelial cells (HUVEC) was examined by tube formation assay and chick chorioallantoic membrane assay. Bioinformatics database predicted the downstream microRNA (miRNA) and target genes of LINC00665, and the relationship between LINC00665, miR-126-5p and vascular endothelial growth factor A (VEGFA) was verified by RT-qPCR, Western blot and dual-luciferase reporter gene assay.Results:The expression level of LINC00665 in HCC (6.5±2.8) was significantly higher than that in paracancer tissues (4.8±3.1), the difference was statistically significant ( t=4.12, P<0.001). According to the median LINC00665 expression level of 100 patients with HCC, the cumulative survival rate of LINC00665 high expression group ( n=50) was lower than that of LINC00665 low expression group ( n=50), and the difference was statistically significant (χ 2=3.79, P=0.008). After co-culture with LINC00665 group (Hep-3B cells overexpressing LINC00665), the length of HUVEC cell tubule formation was (596.0±22.3) μm, and the number of HUVEC cell tubules was (36.3±4.5), which were both higher than NC group with the tubule formation length (127.0±13.5) μm and the number (9.3±1.5) of HUVEC cells co-cultured with Hep-3B cells of control group, and the differences were statistically significant ( t=31.15, 9.82, P<0.001, P=0.001). The chick chorioallantoic membrane assay results were similar to tube formation assay. Western blot detected that the relative expression of VEGFA in LINC00665 group was higher than that in NC group, the difference was statistically significant ( t=7.15, P<0.001). StarBase and DIANA database were used to predict and screen LINC00665 downstream miR-126-5p. StarBase database was used to predict the binding sites of LINC00665/miR-126-5p/VEGFA axis. In dual-luciferase reporter gene assay, the fluorescence intensity of LINC00665 and VEGFA vector co-transfected with miR-126-5p mimics decreased. Conclusion:LINC00665 is highly expressed in HCC and is associated with poor prognosis in patients with HCC. LINC00665 promotes angiogenesis of HCC by regulating the miR-126-5p/VEGFA axis.