SENSITIVE P-32 HPLC TECHNIQUE SHOWS BASE SEQUENCE-DEPENDENT DIFFERENCES IN PHOTOLESION REPAIR IN HUMAN KERATINOCYTES

Understanding the basis for individual susceptibility to skin cancer r equires an understanding of the factors contributing to tumorigenesis. One such factor is the ability of the cell to repair DNA lesions indu ced following insult to the genome. Currently, research in this field is hampered by the lack of a suitably sensitive and specific method fo r the detection of DNA lesions. Developed previously P-32-HPLC in vitr o analysis is applied in this study to measure UVB-induced dipyrimidin e photolesions in human keratinocyte cultures. The high sensitivity of this method permitted the detection of individual cyclobutane pyrimid ine dimers and 6-4 photoproducts in cells irradiated with UVB at doses below one minimal erythema dose. Using this technique one could detec t approximately a 2-fold difference in a base sequence repair of photo lesions. The rates of repair in the chromosomally unstable HaCaT kerat inocyte cell line and in cultured primary human keratinocytes were com pared. The presented data indicate the potential of the P-32-HPLC meth od for the study of DNA repair in cultured cells as well as for biomon itoring studies in humans. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.