Curcumin suppresses renal carcinoma tumorigenesis by regulating circ-FNDC3B/miR-138-5p/IGF2 axis

Curcumin has a vital role in the development of renal carcinoma. Nevertheless, the mechanism of curcumin in renal carcinoma tumorigenesis remains largely unknown. Thirty renal carcinoma patients were recruited. Renal carcinoma cell lines CAKI-1 and ACHN were exposed to curcumin. The levels of circular RNA fibronectin type III domain–containing protein 3B (circ-FNDC3B), microRNA (miR)-138-5p and insulin-like growth factor 2 (IGF2) were detected via quantitative reverse transcription PCR or western blot. Cell proliferation and apoptosis were investigated via 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide, colony formation analysis, flow cytometry and western blot. Target association between miR-138-5p and circ-FNDC3B or IGF2 was analyzed via dual-luciferase reporter analysis. The function of curcumin in vivo was assessed via a xenograft model. circ-FNDC3B level was enhanced and miR-138-5p abundance was declined in renal carcinoma tissues and cells. Curcumin restrained renal carcinoma cell proliferation and promoted apoptosis. circ-FNDC3B overexpression or miR-138-5p knockdown weakened the influence of curcumin. circ-FNDC3B knockdown hindered cell proliferation and promoted apoptosis by increasing miR-138-5p. IGF2 was targeted via miR-138-5p and positively regulated via circ-FNDC3B. Curcumin decreased xenograft tumor growth via reducing circ-FNDC3B in vivo. Curcumin suppressed renal carcinoma tumorigenesis in vitro and in vivo via regulating circ-FNDC3B/miR-138-5p/IGF2 axis, proposing new insight into renal carcinoma tumorigenesis.