The suppressing role of miR-622 in renal cell carcinoma progression by down-regulation of CCL18/MAPK signal pathway

BACKGROUND: MicroRNAs have emerged as critical modulators of carcinogenesis and tumor progression including renal cell carcinoma (RCC). MiR-622 plays as a tumor inhibitor in some types of cancer, however, its role in kidney cancer is unknown. The purpose of the present work is to investigate the functional behaviors and regulatory mechanism of miR-622 in RCC. RESULTS: We examined the expression of miR-622 in RCC and adjacent normal tissues and then explored the roles of miR-622. The results of this analysis indicated that miR-622 activity was significantly downregulated in RCC tissues compared with the corresponding normal tissues, so did in RCC cell lines. MiR-622 was associated with RCC aggressiveness. MiR-622 in RCC cells decreased CCL18 expression and suppressed CCL18 activated MAPK signal pathway. Using Western blot and luciferase reporter assays, it was verified that CCL18 was a direct target of miR-622. A specific and inverse correlation between miR-622 and CCL18 expression was found in human RCC samples. CONCLUSIONS: The results demonstrated that miR-622 acted as a tumor-promoting miRNA by targeting CCL18 in RCC.