Activation of expression of the c-fos oncogene by UVA irradiation in cultured human skin fibroblasts

Both broad-spectrum and near-monochromatic (334 mm, 365 nm and 405 nm) UVA (320-380 nm) and near-visible radiations strongly activate accumulation of mRNA corresponding to the nuclear oncogene and transcription factor, c-fos, in cultured human skin fibroblasts within a dose-range encountered in the environment. The oxidizing component of UVA is clearly of central importanc e to the activation observed because the absence of reduced glutathione str ongly enhances the response. In contrast to observations in rodent cells, w e observe negligible activation of the gene in human cells after UVB (290-3 20 mm) radiation. The results of this study provide evidence that WA radiat ion strongly activates c-fos gene expression in human dermal fibroblasts, a phenomena that is likely to be reflected in UVA-mediated modulation of gen es containing active AP-1-based enhancer elements in the promoter region.