Photosensitized reactions and carcinogenesis.
We present data from experiments designed to investigate the role of DNA interstrand cross-links induced by exposure to 8-MOP plus UVR and skin carcinogenesis. 8-MOP was administered topically to two strains of hairless mice, SKH:hairless-1 and HRS/J/An1, which were then exposed to UV light sources with emission in the range of 1) 300-400, 2) 320-400, and 3) predominantly 365 nm. We found no strain dependency for DNA cross-link production, but a marked strain-dependent difference in tumor susceptibility was noted. Only a small strain-dependent difference occurred in tumor incidence when TPA was administered after exposure to 8-MOP and 320-400 nm. These results suggest that the events concerned with tumor promotion are dependent on strain. Because the most effective tumorigenic wavelength spectrum was 300-400 nm, we investigated the possibility of interaction between lesions induced by the 300- to 320-nm wavelengths and the psoralen photoadducts. In the course of this experiment, we found that the tumorigenic effect was also dependent on the time interval between exposures to 8-MOP plus 365-nm light.
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000209:etiology; D003043:Cocarcinogenesis; D004247:DNA / Q000528:radiation effects*; D005260:Female; D008730:Methoxsalen / Q000008:administration & dosage*; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000209:etiology; D009381:Neoplasms, Radiation-Induced; D010778:Photochemotherapy / Q000009:adverse effects; D012878:Skin Neoplasms / Q000209:etiology*; D013045:Species Specificity; D013755:Tetradecanoylphorbol Acetate / Q000008:administration & dosage; D014466:Ultraviolet Rays / Q000009:adverse effects*
D004247:DNA; D013755:Tetradecanoylphorbol Acetate; D008730:Methoxsalen