The Oncogenic Capacities of Long Noncoding RNA SNHG1 in Bladder Cancer by inducing proliferation and repressing apoptosis via upregulation of microRNA-9-3p-targeted MDM2

Background The involvement of long noncoding RNA small nucleolar RNA host gene 1 (lncRNA SNHG1) was documented in numerous cancers, including bladder, pancreatic and prostate cancers. However, the further mechanistic investigation of SNHG1 in bladder is still needed to conduct. With this purpose, tissue, cell, and animal experiments were implemented in our research to figure out the specific mechanism of SNHG1 in bladder cancer via microRNA-9-3p (miR-9-3p). Methods In harvested bladder cancer tissues, RNA-FISH and RT-qPCR were adopted for SNHG1 expression measurement and RT-qPCR for miR-9-3p expression determination. The impacts of SNHG1, miR-9-3p, MDM2, and PPARγ on cell viability, proliferation, and apoptosis were evaluated by gain- and loss-of-function approaches. RT-qPCR and western blot analysis were performed to detect expression of MDM2, PPARγ, and apoptosis-related factors. RNA pull-down, RIP, dual luciferase reporter gene assay, and IP experiment were utilized to assess the modulatory relationship among SNHG1, miR-9-3p, MDM2, and PPARγ. Tumorigenic ability of bladder cancer cells was measured in vivo. Results High SNHG1 and poor miR-9-3p expression was identified in bladder cancer tissues and cells. Mechanistically, SNHG1 bound to miR-9-3p which negatively targeted MDM2. MDM2 augmented PPARγ ubiquitination to downregulate PPARγ. Bladder cancer cell proliferation was diminished and cell apoptosis was enhanced by silencing SNHG1 or MDM2 or overexpressing miR-9-3p. Similarly, SNHG1 silencing orchestrated miR-9-3p/MDM2/PPARγ axis to depress bladder cancer cell tumorigenesis in vivo. Conclusion In summary, the obtained data provided the novel insight of the anti-oncogenic mechanism of silencing SNHG1 in bladder cancer by activating PPARγ via downregulation of miR-9-3p-targeted MDM2.