Background: Ultraviolet (UV) B light is an environmental mutagen that induces changes in cutaneous gene expression leading to immune suppression and carcinogenesis. Keratinocytes are a primary target for UVB.
Objective: To further delineate UVB-induced gene expression changes in keratinocytes.
Methods: cDNA microarray technology was utilized to examine gene expression in normal human KC (NHKC) following 20 mJcm(-2) UVB irradiation. Data was confirmed by semi-quantitative RT-PCR.
Results: Microarray analysis revealed 57 genes were upregulated, and 27 genes were downregulated, by at least two-fold following UVB. One downregulated gene was the endogenous angiogenesis inhibitor thrombospondin-1 (TSP-1). Semi-quantitative RT-PCR confirmed persistent downregulation of TSP-1 up to 18h following UVB. Microarray analysis also revealed upregulation of platelet-derived endothelial cell growth factor (PD-ECGF)--an angiogenesis activator.
Conclusion: Our results suggest a gene expression mechanism by which UVB induces an angiogenic switch in keratinocytes. This may represent an important early event promoting neovascularization and growth of cutaneous neoplasms.
Copyright 2004 Japanese Society for Investigative Dermatology