(Department of Dermatology and Aesthetic Surgery the Fifth People’s Hospital of Huai’an, Huai’an 223300, China)

Abstract: This study focused on the effects of the differential expression of microRNA-126-3p (miR-126) on migration and invasion of human cutaneous melanoma (CM) cell line C8161, and the role of Janus tyrosine protein kinase 2/signaling and transcriptional activator 3 (JAK2/STAT3) pathway and epithelial-mesenchymal transition (EMT) process were investigated. Dysregulation of miR-126 was achieved by cell transfection, and miR-126-deregulated cells were treated with the JAK2/STAT3 pathway inhibitor AG490 or the agonist Coumermycin A1. Thus, C8161 cells were divided into 5 groups: control group (without transfection or drug treatment), negative control (NC) group (with mimics control transfection, but no drug treatment), miR-126 group (with miR-126 mimics transfection, but no drug treatment), miR-126 + pathway inhibitor group (with miR-126 mimics transfection and AG490 treatment), miR-126 + pathway agonist group (with miR-126 mimics transfection and Coumermycin A1 treatment). Real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the expression level of miR-126. The expression levels of EMT key proteins and JAK2/STAT3 pathway proteins were determined by Western blotting. Cell viability, migration and invasion abilities were determined by cell counting kit-8 (CCK-8), scratch healing assay and Transwell chamber combined with matrix gel, respectively. Compared with the NC group, transfection with miR-126 mimics significantly increased the expression level of miR-126 in the miR-126 group (#P<0.05), while the relative cell vitality, cell migration rate and cell invasion number significantly decreased (#P<0.05), accompanied with higher protein level of E-cadherin (#P<0.05), and lower protein levels of Vimentin, N-cadherin, fibronectin (FN), JAK2, STAT3, p-JAK2, and p-STAT3, and as well as lower ratios of p-JAK2/JAK2 and p-STAT3/STAT3 (#P<0.05). More importantly, compared with NC group and miR-126 group, the  above indicators of JAK2 and STAT3 protein levels were further changed in miR-126 + pathway inhibitor group (#P<0.05 and &P<0.05), whereas all the above indexes were less changed in miR-126 + pathway activator group (#P<0.05 and &P<0.05), and cell invasion number and FN, JAK2 and STAT3 protein levels in miR-126 + pathway activator group were little different from NC group without significance. Overexpression of miR-126 inhibits cell viability, migration and invasion of human CM cells presumably by blocking EMT process and inhibiting the activation of JAK2/STAT3 pathway. These results were helpful to provide a new theoretical basis for the clinical treatment of human CM and a new strategy for its treatment.

Key words: cutaneous melanoma; microRNA-126-3p; Janus tyrosine protein kinase 2/signal transduction and transcription activator 3; migration; invasion

（Acta Laser Biology Sinica, 2024, 33(2): 167-175）