Molecular profiling of ADAM12 and ADAM17 genes in human malignant melanoma.

ADAM12 and ADAM17 proteins belong to a family of transmembrane disintegrin-containing metalloproteinases (ADAMs) involved in the proteins ectodomain shedding and cell-cell and cell-matrix interactions. However, the specific biological functions of ADAMs are still unclear and, until now, these proteins were not investigated yet in melanoma. The aim of this study was to analyze the splicing variants of ADAM12 (L and S) and ADAM17 gene expression in melanoma at transcriptional and translational level in comparison with control (non-tumor) tissues. Taking in account that ADAM17 sheddase is involved in the modulation of TNF-α (tumor necrosis factor alpha), we analyzed also this cytokine in the plasma of the same patients before any treatment, and we compared the results with healthy controls. Quantitative-RT-PCR and immunohistochemistry were used to analyze ADAM12 and ADAM17 genes expression and the analysis of TNF-α expression was carried out in the plasma using ELISA. We demonstrated that ADAM12L splicing variant together with ADAM17 gene are strongly overexpressed in melanomas, whereas ADAM12S, although up-regulated when compared with the non-tumor controls, the difference was not statistically significant. When we compared the levels of expression for the ADAMs genes according to the tumor stage, we observed that all three investigated genes were significantly overexpressed in advanced stage in comparison with early stage melanomas. In the plasma of the same patients, the expression of TNF-α was up-regulated and significantly correlated with the expression of ADAM17 and respectively, with the advanced tumor stage.