Circ-AFAP1 promote clear cell renal cell carcinoma growth and angiogenesis by the Circ-AFAP1/miR-374b-3p/VEGFA signaling axis

Clear cell renal cell carcinoma (ccRCC) is one of the most common urogenital tumors with high mortality. Circular RNA (circRNA), as an emerging endogenous RNA, has been proved to play a crucial role in the clear cell renal cell carcinoma (ccRCC) progression. In this study, we obtained circAFAP1 upregulated in ccRCC by high-sequencing and verified by qRT-PCR in several renal cancer cell lines. In situ hybridization (ISH) assays and Kaplan–Meier plot showed a higher level of circAFAP1 was linked to shorter overall survival. Moreover, CCK8, colony formation, and EdU experiments showed circAFAP1 promoted ccRCC growth while tube formation displayed circAFAP1 contributed to ccRCC angiogenesis. We predicted the downstream miR-374b-3p and VEGFA by bioinformatic analysis and validated further by qRT-PCR, RNA pull-down, RIP, and dual-luciferase. Downregulation miR-374b-3p or overexpression VEGFA could restore proliferation, vascular formation after circAFAP1 silencing. Consistently with the results in vitro, silencing circAFAP1 suppressed ccRCC growth in vivo. In conclusion, the circAFAP1/miR-374b-3p/VEGFA axis played a critical role in the progression and development of ccRCC which might be novel biological marks and therapeutical targets.