Epidermal fatty acid binding protein prevents chemical-induced skin tumorigenesis by regulation of TPA-induced IFN/p53/SOX2 pathway in keratinocytes.

Skin lipids (e.g. fatty acids) are essential for normal skin functions. Epidermal fatty acid-binding protein (E-FABP) is the predominant FABP expressed in skin epidermis. However, the role of E-FABP in skin homeostasis and pathology remains largely unknown. Herein, we utilized the 7,12-dimethylbenz(a)anthracene (DMBA) and 12-O-tetradecanolyphorbol-13-acetate (TPA)-induced skin tumorigenesis model to assess the role of E-FABP in chemical-induced skin tumorigenesis. Compared to their wild type (WT) littermates, mice deficient in E-FABP, but not adipose FABP (A-FABP), developed more skin tumors with higher incidence. TPA functioning as a tumor promoter induced E-FABP expression and initiated extensive flaring inflammation in skin. Interestingly, TPA-induced production of IFNβ and IFNλ in the skin tissue was dependent on E-FABP expression. Further protein and gene expression arrays demonstrated that E-FABP was critical in enhancing IFN-induced p53 responses and in suppressing SOX2 expression in keratinocytes. Thus, E-FABP expression in skin suppresses chemical-induced skin tumorigenesis through regulation of IFN/p53/SOX2 pathway. Collectively, our data suggest an unknown function of E-FABP in prevention of skin tumor development and offer E-FABP as a therapeutic target for improving skin innate immunity in chemical-induced skin tumor prevention.