CircLMTK2 acts as a tumor suppressor in prostate cancer via regulating the expression of microRNA-183

Abstract Background Prostate cancer (PCa) is one of the commonest male urinary and reproductive system malignancies with high morbidity and mortality. circLMTK2 was reported as a tumor suppressor, therefore, we attempted to investigate the potential mechanism of circLMTK2 in PCa. Methods qRT-PCR was employed to examine circLMTK2 and miR-183 expressions. Afterwards, cell transfection was conducted for overexpressing circLMTK2 and miR-183 in LNCaP and PC3 cells, and silencing circLMTK2 in RWPE1 cells. Then, CCK-8 assay, BrdU, transwell, flow cytometry and western blot were conducted to examine the variations of cell growth and metastasis, as well as apoptosis. The expressions of key proteins involved in Wnt/β-catenin and PI3K/AKT pathways were further investigated utilizing western blot. Results circLMTK2 was lowly expressed in tumor tissue. circLMTK2 overexpression suppressed cell proliferation, metastasis, however accelerated cell apoptosis in LNCaP and PC3 cells. circLMTK2 knockdown enhanced cell viability, proliferation, migration and invasion, while had no significant influences on apoptosis of RWPE1 cells. Further experiments verified that miR-183 mimic counteracted the influences triggered by circLMTK2 overexpression in LNCaP and PC3 cells, while promoted the viability, proliferation, migration and invasion of LNCaP cells. Moreover, the inhibitory effects on Wnt/β-catenin and PI3K/AKT pathways evoked by circLMTK2 overexpression were diminished by miR-183 mimic in LNCaP and PC3 cells. Conclusion These outcomes illustrated that circLMTK2 overexpression exerts an anti-tumor effects through down-regulating the expression of miR-183.