SIRT3 Inhibits Cholangiocarcinoma Cell Proliferation by Targeting HIF1α to regulate the EMT Signaling Pathway
Abstract BackgroundCholangiocarcinoma (CCA), is a rare biliary adenocarcinoma associated with poor outcomes. Deacetylase Sirtuin‐3 (SIRT3), a histone deacetylase (HDAC), has been considered to be associated with various cancers and can be a potential new target for CCA.We intended to identify the target of SIRT3 and explore the mechanism of SIRT3 in CCA.MethodsThe expression levels of SIRT3 and hypoxia‐inducible factor‐1α (HIF1α) in CCA tissues and cell lines were examined by RT-qPCR. CCK-8 and EdU methods were used to detect cell proliferation in CCA. To assess the levels of proteins related to cell proliferation and epithelial-mesenchymal transition (EMT) process, western blot analysis was conducted. Co-Immunoprecipitation and deacetylation assays were used to explore HIF1α protein acetylation, stability and the relationship between SIRT3 and HIF1α in CCA cells.ResultsSIRT3 showed low expression in CCA tissues and cells. SIRT3 overexpression inhibited cell proliferation and EMT process. Moreover, the interaction between SIRT3 and HIF1α was confirmed and HIF1α expression was negatively regulated by SIRT3. Furthermore, we also found that HIF1α was more easily degraded and showed a reduction in stability through deacetylation via SIRT3 knockdown. In rescue assays, HIF1α also reversed the inhibitory effect of SIRT3 on cell proliferation and the EMT process. ConclusionsSIRT3 suppressed cell proliferation and the EMT process in CCA by targeting HIF1α.Trial registrationSamples were obtained only after the patient has given informed consent according to the established plan approved by the Ethics Committee of The First Affiliated Hospital of Anhui Medical University.