The occurrence of DNA strand breaks after hyperthermic treatments of mammalian cells with and without radiation

Radiat Res. 1984 Apr;98(1):198-208.

Abstract

Strand breaks were detected in the DNA of Ehrlich ascites cells as well as in HeLa S3 cells directly after 1-5 hr at 43-45 degrees C by the use of the unwinding in high salt/hydroxylapatite method. The strand breaks found could not be attributed to the decay of incorporated tritiated thymidine. When the cells were incubated at 37 degrees C after the hyperthermic treatments, the amount of strand breaks formed remained at a constant level. Hyperthermia inhibited the repair of "radiation-induced" strand breaks. The repair curves obtained this way show a heat-dose-dependent decrease of the relative weight of the fast component of repair. Similar repair curves of "radiation-induced" strand breaks could be obtained by mixing heat inactivated and vital control cells prior to irradiation. In the latter case, however, the DNA repair was inhibited to a greater extent for identical levels of cell survival. The possible underlying molecular mechanisms are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carcinoma, Ehrlich Tumor
  • Cell Line
  • DNA Repair*
  • DNA, Neoplasm* / radiation effects
  • Dose-Response Relationship, Radiation
  • HeLa Cells / radiation effects
  • Hot Temperature*
  • Humans
  • Time Factors

Substances

  • DNA, Neoplasm