RADIOSENSITIVE MELANOMA CELL-LINE WITH MUTATION OF THE GENE FOR ATAXIA-TELANGIECTASIA

The human melanoma cell lines MM96L, A2058 and HT144 were examined for sensitivity to ionizing radiation and UVB radiation. HT144 demonstrat ed a significant increase in sensitivity to ionizing and UVB radiation compared with the MM96L and A2058 cells. Sensitivity to both agents w as associated with susceptibility to apoptosis. Using a protein trunca tion assay, a mutation for the gene for ataxia telangiectasia (ATM) wa s identified in HT144 cells. This was confirmed to be a homozygous mut ation by subsequent sequencing of the abnormal region. Protein truncat ion assay of the other two cell lines showed no abnormality. The resul ts suggest that somatic mutation of the A-T gene may be important in d etermining tumour radiosensitivity.