Jarid2 enhances the progression of bladder cancer through regulating PTEN/AKT signaling

Aims: Jumonji AT-rich interactive domain 2 (Jarid2) is an interacting component of PRC2 which catalyzes methylation of H3K27 (H3K27me3) and causes the downregulation of PTEN. In the present study, we aimed to explore whether Jarid2 could interact with H3K27me3 to regulate PTEN expression in bladder cancer. Main methods: Jarid2 expression in bladder cancer tissues and cells were determined by western blotting and RT-PCR. CCK-8, flow cytometry, transwell chamber and in vivo xenograft assays were performed to assess cell growth, apoptosis, migration and tumorigenesis, respectively. Chromatin immunoprecipitation (ChIP) assay was used to assess the methylation of PTEN. Key findings: Jarid2 expression was increased in bladder cancer tissues and cells. Downregulation of Jarid2 with shRNA transfection obviously inhibited the proliferation, migration and tumorigenesis of bladder cancer T24 and HT-1376 cells and induced cell apoptosis. Jarid2 downregulation decreased the expression of p-AKT and increased PTEN expression. Besides, Jarid2 down-regulation repressed the epithelial-mesenchymal transition (EMT), whereas knockdown of PTEN impaired this effect. Moreover, upregulation of Jarid2 increased the combination of PTEN promoter and H3K27me3, and 5-aza-CdR rescued it. Meanwhile, 5-aza-CdR administration abolished Jarid2 roles in the promotion of EMT process and AKT activation, as well as the reduction of PTEN expression. Significance: Overall, the present study elaborated that Jarid2 facilitated the progression of bladder cancer through H3K27me3-mediated PTEN downregulation and AKT activation, which might provide a new mechanism for Jarid2 in promoting bladder cancer progression.