Hsa_Circ_0001206 is downregulated and inhibits cell proliferation, migration and invasion in prostate cancer.

Our study is to explore the expression profiles and potential functions of circRNAs in prostate cancer (PCa). A total of 95 circRNAs and 830 mRNAs were screened to be significantly differentially expressed in PCa tissues by microarrays. Co-expression and competitive endogenous RNA (ceRNA) network were constructed to reveal the potential regulatory mechanisms of circRNAs. Three circRNAs, hsa_circ_0001206, hsa_circ_0001633, and hsa_circ_0009061 were validated to be down-regulated in PCa by quantitative real-time PCR (qRT-PCR) and hsa_circ_0001206 as well as hsa_circ_0009061 was significantly associated with clinical features of PCa patients. Meanwhile, Receiver Operating Characteristic (ROC) curves showed their good diagnostic value as biomarkers for PCa. The down-regulation of hsa_circ_001206 was partly because of the regulation of DExH-Box Helicase 9 (DHX9). Moreover, overexpression of hsa_circ_0001206 inhibited PCa cell proliferation, migration, and invasion in vitro and prevented tumor growth in vivo. Dual-luciferase reporter assays showed hsa_circ_0001206 could directly bind to miR-1285-5p. The expression of Smad4, a well-known suppressive gene in PCa, can be increased by overexpression of hsa_circ_0001206 and this effect could be partly reversed by co-transfection of miR-1285-5p mimic. The study revealed expression profiles and potential functions of circRNAs and demonstrated hsa_circ_0001206 played a suppressive role in the pathogenesis of PCa.