Long Noncoding RNA PVT1 promoted Gallbladder Cancer proliferation Byepigenetically Suppressing mIR-18b-5p via DNA Methylation
Abstract Background Gallbladder cancer (GBC) accounts for 85–90% malignancies of the biliary tree worldwide. Considerable evidence has demonstrated that dysregulation of lncRNAs are involved in the progression of cancer. LncRNA PVT1 has been reported to play important roles in various cancers, but the role of PVT1 in gallbladder cancer remains unknown. Methods QRT-PCR was used to assess the expression of genes in different tissues or cells. Knockdown or overexpression of PVT1 combined with in vitro and in vivo assays were conducted to determine the effect of PVT1 on the GBC cells proliferation. We also conducted microarray analysis to screen out the miRNA that was regulated by PVT1. BSP was used to detect the methylation status of miR-18b-5p DNA promoter. RIP, ChIP, Co-IP and luciferase reporter assays were performed to validate the association between genes or proteins. Results We found that PVT1 was upregulated in GBC tissues and cells, and its upregulation was related with poor prognosis in GBC patients. PVT1 promoted GBC cells proliferation and increased tumorigenicity in nude mice. Molecular experiments demonstrated that PVT1 recruited DNMT1 via EZH2 to the miR-18b-5p DNA promoter and suppressed the transcription of miR-18b-5p through DNA methylation. Moreover, HIF1A was proved to be the downstream target gene of miR-18b-5p and PVT1 regulated GBC cell proliferation via HIF1A. Conclusions Our studies clarified the PVT1/ miR-18b-5p/ HIF1A regulation axis and indicated that PVT1 could be a potential therapeutic target for GBC.