miR-204-5p and miR-3065-5p exert antitumor effects on melanoma cells.

MicroRNA (miR)-204-5p was previously identified to be downregulated in melanoma compared with melanocytic nevi. This observation prompted a functional study on miR-204-5p and the newly-identified miR-3065-5p, two miRNAs suggested to be tumor-suppressive oncomiRs. Application of miR-204-5p mimics or inhibitors resulted in a decrease or increase, respectively, in melanoma cell proliferation and colony formation. miR-204-5p mimics hindered invasion, whereas miR-204-5p inhibitors stimulated cancer cell migration. Modulation of miR-3065-5p led to a decrease in melanoma cell proliferation, altered cell cycle distribution and increased expression levels of its target genes HIPK1 and ITGA1, possibly due to functional modifications identified in these cells. miR-204-5p and miR-3065-5p demonstrated antitumor capacities that may need to be taken into account in the development of melanoma treatment approaches.

Role of translocator protein in melanoma growth and progression.

The 18 kDa translocator protein (TSPO) is a primarily mitochondrial protein that participates in steroid biosynthesis, cell proliferation, differentiation, apoptosis, and the regulation of mitochondrial function in general. TSPO has been implicated in carcinogenesis via its ability to transport cholesterol into mitochondria to meet the increased energy needs of tumor cells. The purpose of this study was to investigate TSPO involvement in melanoma pathogenesis. TSPO expression in melanoma and melanocytic nevi was analyzed by immunohistochemistry and real-time PCR, and TSPO levels were correlated to the invasiveness of the tumor. The number of TSPO-positive melanoma samples increased with tumor progression irrespective of age or gender of patients. Similar findings were obtained while examining TSPO expression levels in relation to the Clark invasion stage of the tumor. Indeed, the immunohistochemical index was elevated in invasive tumors characterized as Clark level V compared to those characterized as levels I and II. Besides, the elevation of immunohistochemical index was accompanied with a shift of homogeneous cytoplasmic subcellular expression pattern of the protein to nuclear and perinuclear. Taken together, these results suggest TSPO participation in melanoma growth and progression.