Detection of pyrimidine dimers and monoadducts induced by 7-methylpyrido(3,4-c) psoralen and UVA in Chinese hamster V79 cells by enzymatic cleavage and high-pressure liquid chromatography.
The photochemotherapeutically active psoralen derivative 7-methylpyrido(3,4-c) psoralen (MePyPs) has been recently shown to be able to photoinduce monoadducts of the C4-cycloaddition type as well as pyrimidine dimers in DNA in vitro. In the present study, we report on the induction of these two types of photolesions in mammalian cells in culture. The MePyPs photocycloadducts were quantified in V79 Chinese hamster cells after treatment with MePyPs plus UVA following enzymatic hydrolysis of the DNA by DNase I, S1 nuclease and acidic phosphatase treatments. Concomitantly induced pyrimidine dimers were determined by two methods, high-pressure liquid chromatography and alkaline gel electrophoresis after dimer-specific endonucleolytic cleavage. The results show that, in Chinese hamster cells treated with MePyPs plus UVA, the yield of pyrimidine dimers is approximately 5-10% that of MePyPs-DNA photocycloadducts. Because psoralen monoadditions to DNA alone are generally not considered as being very phototoxic, a synergistic interaction of monoadditions with pyrimidine dimers may be expected to occur in order to explain the high photobiological effectiveness of this psoralen derivative.
Institut Curie-Biologie, URA 1292 du CNRS, Paris, France.
M
M
Dardalhon
L A
LA
Guillo
A
A
Moysan
P
P
Vigny
D
D
Averbeck
D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D004591:Electrophoresis, Polyacrylamide Gel; D011564:Furocoumarins / Q000494:pharmacology*; D011743:Pyrimidines / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays
D011564:Furocoumarins; D011743:Pyrimidines; C081211:7-methylpyrido(4,3-c)psoralen; D004247:DNA