circTP63 promotes prostate cancer progression via miR-421/VAMP associated protein A axis

Background: Circular RNAs (circRNA) have a vital role in the progression of cancers. For instance, circTP63 is upregulated in prostate cancer (PCa) tissues compared with adjacent normal tissues. However, the role of circTP63 in prostate cancer is still unclear. Methods: qRT-PCR assays were applied to detected the expression of circTP63 and miR-421 in PCa samples. Functionally, CCK-8, apoptosis assay, and transwell migration and invasion assays were used to explore the role of circTP63 in PCa progression. Mechanistically, the interaction between circTP63 and miR-421 were verified using qRT-PCR and dual-luciferase report assay. Western blot, qRT-PCR, and dual-luciferase report assay were applied to detect the interaction between miR-421 and VAMP associated protein A (VAPA). And xenograft animal model was used to detect the role of circTP63 in vivo. Results: circTP63 was upregulated and miR-421 was downregulated in PCa tissues. Functional assays revealed that circTP63 promoted the proliferation and metastasis of PCa cells in vitro. In addition, the inhibition effect of circTP63 knockdown could be rescued by miR-421 inhibition or VAPA overexpression. Mechanistically, circTP63-mediated PCa progression through directly binding to miR-421, and subsequently releasing the VAPA. In vivo, silencing of circTP63 significantly impaired PCa progression. Conclusion: In summary, our study identified circTP63 as an oncogenic circRNA, which could be a promising diagnostic and therapeutic target for PCa treatment.