MicroRNA-497 regulates the proliferation of clear cell renal cell carcinoma via interleukin-6 receptor

Abstract This study determined the expression of microRNA-497 (miR-497) and interleukin-6 receptor (IL-6R) in tumour, blood and urine from patients with clear cell renal cell carcinoma (ccRCC), and examined their relationship with the proliferation of ccRCC. Twenty-eight ccRCC patients and 32 healthy subjects gave peripheral blood and urine samples. Tumour and tumour-adjacent tissues were collected from ccRCC patients. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of IL-6R mRNA and miR-497; Western blotting, to determine IL-6R protein expression in tumour tissues or ccRCC Caki-1 cells; enzyme-linked immunosorbent assay, to measure the content of IL-6R protein in blood or urine; dual luciferase reporter assay, to test the direct interaction between miR-497 and the 3′-untranslated region (UTR) of IL-6R mRNA; MTT (methyl thiazolyl tetrazolium) assay, to determine the proliferation of cells. The expression of IL-6R mRNA and protein was significantly higher in tumour tissues than in tumour-adjacent tissues. Similarly, the expression of IL-6R mRNA and protein in blood and urine was significantly higher in ccRCC patients than in healthy subjects. The levels of miR-497 in tumour tissues, blood and urine from ccRCC patients were decreased. miR-497 bound with the 3′-UTR of IL-6R mRNA to regulate the expression of IL-6R. Overexpression of miR-497 inhibited the proliferation of ccRCC Caki-1 cells by down-regulating the expression of IL-6R. These results demonstrate that up-regulation of IL-6R expression in tumour tissues, blood and urine from ccRCC patients is related with the down-regulation of miR-497 expression. miR-497 might regulate the proliferation of ccRCC via IL-6R