Differential features of sister-chromatid exchange responses to ultraviolet radiation and caffeine in xeroderma pigmentosum lymphoblastoid cell lines

Mutat Res. 1983 Feb;107(2):387-96. doi: 10.1016/0027-5107(83)90178-1.


Sister-chromatid exchange (SCE) induced by ultraviolet (UV) irradiation and viability after UV irradiation were studied in lymphoblastoid cell lines derived from 7 patients with xeroderma pigmentosum (XP) and 6 normal donors. UV irradiation caused significant increases of SCEs in both XP and normal cells. In 3 XP cell lines, which were deficient in unscheduled DNA synthesis (UDS) and sensitive to the killing effect of UV, very high SCE frequencies were observed after UV irradiation. Cells from a patient with the De Sanctis-Cacchione syndrome were the most sensitive to UV in terms of both SCE induction and cell killing. In 2 of 4 UDS-proficient XP cell lines tested, the incidences of UV-induced SCEs were similar to those in normal cell lines, but in 2 other UDS-proficient lines from 2 XP patients with skin cancer, the frequencies of UV-induced SCEs were significantly higher than in normal cells. Continuous post-UV treatment with 1 mM caffeine markedly enhanced UV-induced SCEs in 3 of 4 UDS-proficient XP cell lines but had only slight effects on cells from the 4th UDS-proficient XP patient and from normal individuals.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caffeine / pharmacology*
  • Cell Line
  • Cell Survival / radiation effects
  • Crossing Over, Genetic / radiation effects*
  • DNA / biosynthesis
  • DNA Repair / radiation effects
  • Humans
  • Lymphocytes
  • Sister Chromatid Exchange / drug effects
  • Sister Chromatid Exchange / radiation effects*
  • Ultraviolet Rays
  • Xeroderma Pigmentosum / genetics*


  • Caffeine
  • DNA