Abstract
PURPOSE: Circular RNAs (circRNAs) are a class of covalently closed circular RNA transcripts and have been found to regulate the progression of human malignancies. The objective of this study was to identify the functions of circRNAs in breast cancer (BCa). PATIENTS AND METHODS: BCa and adjacent non-cancerous tissues were collected from 99 patients. Kaplan-Meier analysis was used to analyze the relationship between circPVT1 and prognosis. CircPVT1 expression levels in BCa tissues and cell lines were detected via PCR. Transfection technology was used to silence circPVT1 and overexpress miR-204-5p. Cell biological behavior was analyzed, and epithelial-mesenchymal transition (EMT) related proteins were detected by Western blot. In vivo experiments were performed with the subcutaneous xenograft tumor model. RESULTS: CircPVT1 was markedly overexpressed in BCa tissues and cell lines. Higher expression of circPVT1 was correlated with poor prognosis of BCa patients. Knockdown circPVT1 significantly suppressed the proliferation, migration and invasion of BCa cells invitro, and suppressed BCa tumor growth invivo. CircPVT1 knockdown upregulated E-cadherin and downregulated N-cadherin, Vimentin, Slug and Twist in BCa cells. Moreover, circPVT1 could serve as a competing endogenous RNA (ceRNA) for miR-204-5p, and restoration of miR-204-5p abrogated the oncogenic role of circPVT1 in BCa cells. CONCLUSION: CircPVT1 as a potentially valuable biomarker for BCa diagnosis and therapeutic target for BCa treatment. CircPVT1 might promote the invasion and EMT of BCa cells by serving as aceRNA for miR-204-5p.