CircRNA circPDSS1 promotes bladder cancer by down-regulating miR-16

Background: Circular RNA (circRNA) circPDSS1 is a recently identified oncogene in gastric cancer, while its roles in other types of cancer are unknown. We investigated the functions of circPDSS1 in urothelial bladder cancer (UBC). Materials and methods: Seventy-two patients (50 males and 22 females, age 38–69 years, mean: 52.3 ± 6.3 years) with UBC were enrolled in Gansu Provincial People’s Hospital from August 2015 to August 2018. RT-qPCR was used to measure gene expression levels in both biopsies from UBC patients and in vitro cultivated HT-1197 and UMUC3 cells. Cell transfections were performed to analyze gene interactions. Cell proliferation, transwell migration and invasion assays were performed to analyze the effects of transfections on HT-1197 and UMUC3 cell proliferation, migration and invasion, respectively. Results: We found that circPDSS1 was up-regulated in UBC. Expression levels of circPDSS1 were increased with increase in clinical stages. MiR-16 was down-regulated and correlated with circPDSS1 in UBC. Overexpression of circPDSS1 led to down-regulation of miR-16, while miR-16 overexpression failed to significantly affect circPDSS1. Overexpression of circPDSS1 led to increased proliferation, invasion and migration rates of UBC cells. Overexpression of miR-16 not only led to inhibited proliferation, invasion and migration of UBC cells, but also attenuated the effects of circPDSS1 overexpression. Conclusion: Therefore, circRNA circPDSS1 may promote UBC by down-regulating miR-16.