LncRNA KCNK15-AS1 inhibits pancreatic cancer progression by promoting the expression of its binding protein ACTR3B

Abstract Background LncRNAs are reported to play an essential role in multiple tumors, including pancreatic cancer. LncRNAs could impact tumor growth via RNA-binding proteins, working as a coactivators of transcription factors or impacting their gene expression via posttranscriptional regulation. Our study aimed to elucidate the function and mechanism of lncRNA KCNK15-AS1 and its binding protein ACTR3B in PC progression. Our previous data indicated that KCNK15-AS1 is downregulated in PC tissues and cell lines compared to normal controls. Methods In this study, we overexpressed KCNK15-AS1 and ACTR3B in both BxPC-3 and Mia-PaCa-2 cells to detect the cellular phenotype in vitro and in vivo. RNA pulldown assays, mass spectrometry assays and RNA-binding protein immunoprecipitation assays were used to verify KCNK15-AS1 RNA binding protein ACTR3B. Luciferase reporter assay and ubiquitination assay were proceeded to detect the mechanism KCNK15-AS1 upregulated ACTR3B expression. Results Our results showed that overexpression of KCNK15-AS1 significantly inhibited the proliferation, colony formation and migration of PC cells. ACTR3B was screened by RNA pulldown and mass spectrometry assays. RNA-binding protein immunoprecipitation assays confirmed that KCNK15-AS1 physically bound to ACTR3B. Furthermore, mechanistic analyses demonstrated that KCNK15-AS1 promoted ACTR3B expression by inhibiting ACTR3B ubiquitin-mediated degradation and enhancing its promoter activity. Additionally, ACTR3B presented low expression in PC tissues and cell lines, and PC cell growth was significantly repressed when ACTR3B was overexpressed. Moreover, knockdown of ACTR3B in KCNK15-AS1-overexpressing cells reversed the effects of KCNK15-AS1 on PC cell growth via the cyclin D1/CDK4 axis. Conclusion Briefly, our study indicated that the lncRNA KCNK15-AS1/ACTR3B/cyclin D1/CDK4 axis may inhibit PC progression, which provides a potential therapeutic target for PC.