Long non-coding RNA HCP5 promotes proliferation and metastasis of clear cell renal cell carcinoma via targeting miR-140-5p/IGF1R pathway.

Abstract

The expression pattern, biological function and action mechanism of long noncoding RNA HCP5 in clear cell renal cell carcinoma (ccRCC) remain elusive. The quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to measure the abundance of HCP5 and miR-140-5p in HCC tissues and cells. Kaplan-Meier survival analysis was used to analyze the prognostic role of HCP5 for the patients. Cell proliferation, apoptosis, as well as cell cycle and metastasis were detected by CCK-8, flow cytometry, transwell migration and invasion assays, respectively. The binding sites between miR-140-5p and HCP5 or IGF1R were predicted by bioinformatic sites, and the direct interaction was confirmed by Dual-Luciferase reporter assay or RIP-ago2 assay. Western blot assay was used to detect the expression of target gene. Xenograft model was established to validate the function of HCP5 in vivo. The expression of HCP5 was significantly upregulated in ccRCC tissues and cells. Moreover, patients with high HCP5 expression level had unfavorable overall survival (OS) and progression-free survival (PFS) compared to those with low HCP5 expression. Additionally, HCP5 knockdown led to the prohibition of ccRCC cell proliferation, colony formation, migration, and invasion; the promotion of cell cycle arrest at G0-G1 and apoptosis in vitro; and the inhibition of tumor growth in vivo. Mechanically, miR-140-5p was certified as an inhibitory target of HCP5. Furthermore, insulin-like growth factor-1 receptor (IGF1R) was identified as a direct target of miR-140-5p in ccRCC cells. Finally, we found that the inhibitory effects of the HCP5 silencing on functional behaviours were neutralized by miR-140-5p silencing. HCP5 serves as a competing endogenous RNA that regulated IGF1R expression by sponging miR-140-5p in ccRCC. Hence, the HCP5/miR-140-5p/IGF1R pathway might be a promising therapeutic target in ccRCC.