INCREASED SUSCEPTIBILITY OF MOUSE CELLS TO FLUORESCENT LIGHT-INDUCED CHROMOSOME-DAMAGE AFTER LONG-TERM CULTURE AND MALIGNANT TRANSFORMATION

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 39  (3) , 929-933
Abstract
Exposure of mouse cells in culture to fluorescent light produces chromatid breaks and exchanges. H2O2 formed in the cell during illumination was implicated as the causative agent. Susceptibility to light-induced chromosome damage increases with time in culture and seems to be associated with or requisite for the spontaneous malignant transformation of mouse cells. All 3 cell lines followed during long-term culture that either became tumorigenic or showed cytological evidence of neoplastic transformation developed a concomitant in crease in susceptibility. In 3 additional cell lines, susceptibility to light-induced chromatid damage was significantly increased in the spontaneously transformed malignant cells as compared with their nonneoplastic precursors. The increased susceptibility is not simply the result of long-term culture, since 3 other nonneoplastic cell lines after prolonged culture were significantly less susceptible than their malignant counterparts. Increased susceptibility to light-induced chromatid damage could result from impaired DNA repair or from the loss of defense mechanisms for destroying H2O2 or scavenging free radicals.