FUROCOUMARIN SENSITIZATION INDUCES DNA-PROTEIN CROSS-LINKS

The capacity of some linear and angular furocoumarins to induce DNA-pr otein cross-links by UVA (320-400 nm) irradiation has been evaluated i n Chinese hamster ovary cells. Two linear furocoumarins, psoralen and 8-methoxypsoralen appeared to be capable of inducing DNA-protein cross -links to a noticeable extent. 4'-Methylangelicin and 4,4'-dimethylang elicin formed only reduced amounts of DNA-protein cross-links, while a ngelicin and 4,6,4'-trimethylangelicin seemed to be unable to induce s ignificant levels of this lesion. The biological significance of this damage remains to be elucidated, but it might have an important role i n furocoumarin sensitization. In the examined compounds, the capacity for inducing DNA-protein cross-links appears to be a property of the s kin phototoxic furocoumarins. This result suggests the hypothesis of a connection between this damage and the formation of skin erythemas.