Long noncoding RNA PVT1 modulates hepatocellular carcinoma cell proliferation and apoptosis by recruiting EZH2

Background: We aimed to figure out the molecular network of PVT1 and EZH2 on hepatocellular carcinoma (HCC) cells growth. We also explored the interaction between PVT1, EZH2, MDM2 and P53. Methods: Microarray analysis was performed to screen for abnormally expressed genes in HCC tissues and PVT1 was identified as one gene significantly upregulated in HCC. CCK-8 assay, colony formation assay, and flow cytometry detected cell vitality, proliferation and apoptosis, respectively. RIP and RNA pull-down assays were employed to examine the connection between PVT1 and EZH2. The effect of PVT1 on the stability of EZH2 protein and the impact of EZH2 on MDM2 were detected by ELISA. Co-immunoprecipitation assay was used to evaluate the relationship between MDM2 and EZH2. Western blot detected the expression of EZH2, MDM2 and P53. Results: Up-regulated PVT1 was detected in HCC. Knockdown of PVT1 inhibited HCC cell propagation and promoted apoptotic cells. PVT1 could improve EZH2 protein stability by binding to EZH2 protein but have no significant impact on EZH2 mRNA expression. EZH2 protein stabilized MDM2 protein expression by binding to MDM2 protein. PVT1 enhanced the protein expression of EZH2 and MDM2 as well as inhibited P53 protein expression. Conclusions: PVT1 promoted HCC cell propagation and inhibited apoptotic cells by recruiting EZH2, stabilizing MDM2 protein expression and restraining P53 expression.