Sex-dependent interaction of PTGS2 with miR-146a as risk factor for melanoma and the impact of sex hormones in gene expression in skin cells.

Gender disparity in melanoma is a complex issue where sex hormones could be engaged. Differences in genetic variations are important in understanding the mechanisms of sex disparity in melanoma. Post-transcriptional regulation of prostaglandin-endoperoxide synthase (PTGS2) mRNA occurs through a complex interplay of specific trans-acting RNA-binding proteins and microRNAs. MiR-146a is a key player in melanoma, modulating immune responses and tumor microenvironment (TME). Polymorphisms in PTGS2 gene rs20415GC have been associated with an increased risk of melanoma. Epistasis between polymorphisms rs20415GC was investigated by genotyping 453 melanoma patients and 382 control individuals. The effects of testosterone and 17ß-estradiol were analyzed in keratinocytes and two melanoma cell lines. The rs2910164GG showed a higher risk in the presence of the genotype rs20417CC in the male population. Testosterone and 17ß-estradiol act differently on PTGS2 and miR-146a expression, depending on the cell type. Testosterone augments PTGS2 gene expression in keratinocytes and miR-146a in melanoma cells. While 17ß-estradiol only increases miR-146a expression in HaCaT cells. The present study indicates a sex-specific relation between miR-146a and PTGS2 polymorphisms with melanoma cancer risk. Testosterone and 17ß-estradiol act differently on the expression of PTGS2 and miR-146a depending on the skin cell type.