Targeting GOLM1 by microRNA-200a in melanoma suppresses cell proliferation, invasion and migration via regulating PI3K/Akt signaling pathway and epithelial-mesenchymal transition.

OBJECTIVE: Metastatic melanoma, which is refractory to therapies, is one of the most aggressive types in skin cancers. microRNAs (miRNAs) have recently emerged as novel molecules which have therapeutic effects on melanoma. This study focused on the roles and mechanisms of miR-200a in melanoma progression. PATIENTS AND METHODS: Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine the level of miR-200a expression in 46 pairs of melanoma tissues and para-cancerous specimens, and the relationship between miR-200a level and clinical features of melanoma patient prognosis was analyzed. MiR-200a expression in melanoma cells was further verified by qRT-PCR. In addition, we identified the biological target of miR-200a using TargetScan. To delineate the molecular mechanism underlying the tumor-suppressive roles of miR-200a in melanoma, Western blots were performed to determine the functions of miR-200a in PI3K/Akt pathway and EMT.
RESULTS: QRT-PCR analysis demonstrated a prominent decrease of miR-200a in melanoma tissues, which was associated with the poor prognosis and malignant clinicopathologic features of melanoma patients. Moreover, functional assays indicated that miR-200a overexpression markedly repressed melanoma cell proliferation, invasion, and migration capacities. A luciferase reporter analysis showed that Golgi membrane protein 1 (GOLM1) was a functional target of miR-200a in melanoma cells. Western blot analysis revealed that miR-200a inhibited melanoma progression by regulating PI3K/Akt signaling pathway and epithelial-mesenchymal transition (EMT). It was also found that miR-200a upregulation markedly suppressed melanoma tumorigenesis in vivo. All these data showed that miR-200a served as a promising therapeutic target in melanoma patients.
CONCLUSIONS: We provided evidence that miR-200a was down-regulated in melanoma and was implicated in melanoma progression via inhibiting GOLM1 expressions and regulating PI3K/Akt signaling pathway and EMT. Decreased levels of miR-200a were related to poor prognosis of melanoma patients. Findings of the present study provided a novel insight into understanding melanoma pathogenesis, suggesting that miR-200a may function as a promising and potential therapeutic biomarker for melanoma treatments.