UVB radiation suppresses Dicer expression through β-catenin.

Ultraviolet (UV) rays prompt a natural response in epidermal cells, particularly within melanocytes. The changes in gene expression and related signaling pathways in melanocytes following exposure to UV radiation are still not entirely understood. Our findings reveal that UVB irradiation suppresses the expression of Dicer (also known as Dicer1). This repression is intricately linked to the activation of the phosphoinositide 3-kinase (PI3K), ribosomal S6 kinase (RSK) and Wnt-β-catenin signaling pathways, and is directly associated with transcriptional repression by β-catenin (also known as CTNNB1). Notably, we have identified specific binding sites for the TCF/LEF-β-catenin complex in the Dicer promoter. Collectively, these results emphasize the significance of the UV-induced pathway involving the TCF/LEF-β-catenin complex, which impacts Dicer expression. UV radiation also reduced the levels of specific microRNAs known to be important in the biology of melanocytes. This pathway holds potential importance in governing melanocyte physiology.