miR-106b-5p promotes cell cycle progression of malignant melanoma by targeting PTEN

This study investigated how miR-106b-5p/PTEN signaling affects the cell cycle of malignant melanoma (MM) cells. miR-106b-5p mRNA was identified with qRT-PCR. Through transient transfection, miR-106b-5p or PTEN was upregulated and downregulated in MM cells. With such transfected cells, MTT assay, colony formation assay and flow cytometry were carried out to investigate the role of miR-106b-5p in cell cycle progression after the transfected cells were treated with reverse-regulation of miR-106b-5p or PTEN. Western blot analysis was used to quantify all proteins, and a luciferase reporter assay was carried out to validate miR-106b-5p targeting PTEN. miR-106b-5p mRNA was overexpressed in MM tissues and cell lines. MM cells with upregulated miR-106b-5p presented faster growth and shorter cell cycles, while those with knockdown of miR-106b-5p presented the opposite trend. PTEN was subject to post-transcriptional regulation of miR-106b-5p. Based on such a finding, further exploration was carried out to investigate the interaction between cyclin D1 and P27(Kip1), with the finding that miR-106b-5p can stimulate cyclin D1 and suppress P27(Kip1) via the Akt/ERK pathway. The results of this study suggest that miR-106b-5p may be a promoter in MM progression, possibly by targeting PTEN and thus regulating the downstream cell-cycle-related proteins and Akt/ERK pathway.