Skin fibroblasts from patients with the genetic disorder hereditary hemorrhagic telangiectasia compared with ataxia-telangiectasia fibroblasts in their response to the radiomimetic drug neocarzinostatin.

Skin fibroblasts from patients with hereditary hemorrhagic telangiectasia (HHT) were compared with fibroblasts from patients with the genetic disorder ataxia-telangiectasia (A-T), and with SV40-transformed A-T fibroblasts, regarding their sensitivity to the radiomimetic drug neocarzinostatin (NCS). Whereas A-T fibroblasts were found to be hypersensitive to NCS at low concentrations (as measured by the cellular survival test), as previously reported, the HHT fibroblasts were more resistant to NCS and behaved as normal fibroblasts. The SV40-transformed A-T cells also resembled normal fibroblasts in their response to NCS in the colony formation test. In the DNA synthesis test, HHT strains of fibroblasts did not fully resemble untransformed and SV40-transformed A-T cells that continued to synthesize DNA following NCS treatment, since NCS inhibited DNA synthesis in HHT fibroblasts by 5 to 15%; whereas the same treatment in normal fibroblasts reduced DNA synthesis by 40%.