Identification of miR-199a-5p target genes in the skin keratinocyte and their expression in cutaneous squamous cell carcinoma

• Expression of 56 genes (>2-fold) was changed in the miR-199a-5p overexpressing keratinocyte.
• Bcam, Fzd6, Wnt7a, Ddr1 and Podxl expression was negatively regulated by miR-199a-5p in the skin keratinocyte.
• MiR-199a-5p inhibits migratory capability of skin keratinocyte.
• Expression of BCAM, FZD6 and DDR1 was up-regulated while that of miR-199a-5p down-regulated in cSCC.

BackgroundMicroRNAs (miRNAs) are small non-coding RNA molecules that mediate the biological cellular processes via regulation of target genes through translational repression or mRNA degradation. Among various miRNAs, miRNA-199a (miR-199a) has been known to be involved in cancer development and progression, protection of cardiomyocyte, and skeletal formation.ObjectiveAlthough miR-199a-5p was studied in various cell types, the role of miR-199a-5p and its target genes in skin keratinocyte have not been documented. In this study, we identified target genes of miR-199a-5p in skin keratinocyte.MethodsIn order to identify the target of miR-199a-5p in keratinocyte, microarray analysis was performed. The relative expression of candidate target genes was investigated using quantitative RT-PCR and western blot analysis. To determine whether their expression was directly regulated by miR-199a-5p, luciferase reporter assay was performed. In order to investigate expression of target genes in cutaneous squamous cell carcinoma, immunohistochemistry was performed.ResultsWe identified new target genes, Bcam, Fzd6, and Wnt7a, as well as previously known targets, Ddr1 and Podxl. We found that their expressions were directly regulated by miR-199a-5p in the skin keratinocyte using in vitro study and observed that expression of miR-199a-5p was inversely correlated with those of BCAM, FZD6 and DDR1 in the cSCC. In addition, overexpression of miR-199a-5p resulted in inhibition of the migratory capability of the skin keratinocyte.ConclusionThese results suggested that miR-199a-5p plays a role in pathogenesis of cSCC via inhibition of invasiveness through regulation of BCAM, FZD6 and DDR1 expression.