Overexpression of microRNA-21 inhibits the growth and metastasis of melanoma cells by targeting M K K 3

Abstract

Melanoma is an aggressive skin carcinoma with poor prognosis, and is prevalent worldwide. It was demon¬ strated that microRNA (miR)-21 and mitogen-activated protein kinase kinase 3 (M K K 3) both participated in the occurrence and development of various tumors; however, their detailed roles in the progression of melanoma remain unclear. Reverse transcription-quantitative P C R (RT-qPCR) and western blot analyses were conducted to examine the expression levels of miR-21 and M K K 3 in clinical specimens of patients with melanoma and melanoma cell lines. A dual-luciferase reporter assay was performed to verify the target interaction between miR-21 and M K K 3 . The H I R N A and protein expressions of M K K 3 were measured using RT-qPCR and western blot analysis, respectively, following transfection with miR-21 mimics and inhibitor. Subsequently, Cell Counting Kit-8 and colony formation assays, and flow cytometry were conducted to assess the effects of miR-21 and M K K 3 on the cell growth of melanoma. Cell migration and invasion experiments were performed to evaluate the effects of miR-21 and M K K 3 on the cell metastasis of melanoma. It was revealed that M K K 3 was upregulated, and miR-21 was downregulated in patients with melanoma and melanoma cell lines. M K K 3 was demon¬ strated to be a direct target of miR-21. Furthermore, it was demonstrated that upregulated miR-21 expression and downregulated M K K 3 expression suppressed cell proliferation and colony formation, promoted apoptosis, delayed the cell cycle, and inhibited cell migration and invasion. The present find¬ ings suggested that miR-21 could inhibit the cell growth and metastasis of melanoma by negatively regulating M K K 3 .