miR-455-5p functions as a potential oncogene by targeting galectin-9 in colon cancer.

Although there is evidence that galectin-9 is a critical factor in health and disease, the upstream regulatory microRNA (miRNA or miR) of the protein remains poorly defined. miR-455-5p is characterized as a tumor-associated miRNA in cancer research. However, the actual role of miR-455-5p with respect to inhibiting or promoting tumorigenesis in colon cancer is unclear. The present study aimed to investigate the expression, role and target regulation association of galectin-9 and miR-455-5p in colon cancer. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were used for the detection of the expression levels of galectin-9 and miRNAs. Cell Counting kit-8 test was used for the evaluation of cell proliferation, while flow cytometry was used for cell apoptosis analysis. A potential interaction between galectin-9 and miR-455-5p was predicted by target prediction programs and confirmed by luciferase assay and transfection with miRNA mimics. The present study revealed that elevated expression of galectin-9 and miR-455-5p in colon cancer was associated with HT29 cell proliferation and apoptosis. Furthermore, the present study demonstrated that miR-455-5p reduced galectin-9 expression by directly targeting its 3'-untranslated region. These data suggest that miR-455-5p functions as a potential oncogene in colon cancer by targeting galectin-9.