Cultured Skin Keratinocytes from Both Normal Individuals and Basal Cell Naevus Syndrome Patients are More Resistant to γ-rays and UV Light Compared with Cultured Skin Fibroblasts

Summary

Measurement of colony-forming ability following exposure to γ-rays was performed on cultured skin keratinocytes and skin fibroblasts obtained from normal individuals, basal cell naevus syndrome patients (BCNS) and ataxia telangiectasia (A-T) patients. The most striking observation was the radiation resistance of 8/8 keratinocyte strains compared with fibroblasts whether from BCNS patients or normals. The single A-T keratinocyte cell strain showed the same radiosensitivity as A-T fibroblast cell strains. The differential survival of keratinocytes and fibroblasts was also observed following exposure to 254 nm UV light. The survival curves of SV40 immortalized keratinocytes and retinoblasts derived from normal individuals or BCNS patients showed large shoulder regions following exposure to γ-rays or 254 nm UV light. An increased D₃₇ rather than an increased D₀ was therefore the feature of such curves. This contrasted with the SV40 immortalized A-T keratinocytes or fibroblasts which showed a minimal shoulder effect and an increased D₀. No difference in survival was observed between BCNS and normal cells following exposure to either UV or γ-rays.