Abstract: Objective To explore the role of miR-744-5p/CCND1 axis in clear-cell renal cell carcinoma (ccRCC). Methods We examined the expression levels of miR-744-5p in 65 pairs of ccRCC and adjacent tissue specimens and in 5 ccRCC cell lines and human renal tubular epithelial (HK2) cells using qRT-PCR. The ccRCC cell lines 786-O and OSRC2 were transfected with miR-744-5p mimic, CCND1 mimic, or their negative control mimics, and the changes in cell proliferation, migration, and invasion were evaluated with CCK-8, wound healing, and Transwell assays. The downstream target molecules of miR-744-5p were predicted by bioinformatics analysis, and the expression level of CCND1 in ccRCC cells was verified by qRT-PCR and Western blotting. The relationship between miR-744-5p and CCND1 was further validated by dual luciferase reporter assay, and the role of the miR-744-5p/CCND1 axis in ccRCC was explored by rescue experiments. Results MiR-744-5p was significantly downregulated in ccRCC tissues and cell lines (all P<0.05), and its overexpression inhibited the proliferation, migration, and invasion of ccRCC cells (all P<0.05). Bioinformatics analysis and dual luciferase reporter assay showed that CCND1 was a downstream target of miR-744-5p. The results of rescue experiments showed that upregulation of CCND1 could partially reverse the inhibitory effect of miR-744-5p overexpression on ccRCC cell proliferation, migration, and invasion (all P<0.05). Conclusion MiR-744-5p inhibits the malignant phenotype of ccRCC cells by targeting CCND1, and the miR-744-5p/CCND1 axis may be a novel target for diagnosis and treatment of ccRCC.

Key words: clear-cell renal cell carcinoma; miR-744-5p; CCND1