Inhibitors of poly(ADP-ribose) synthesis enhance X-ray killing of log-phase Chinese hamster cells

Radiat Res. 1984 Mar;97(3):546-55.


Postirradiation incubation of V79 Chinese hamster cells with inhibitors of poly(ADP-ribose) synthesis was found to potentiate the killing of cells by X rays. Potentiation increased with incubation time and with concentration of the inhibitor. Preirradiation incubation had only a small effect. The enhanced response correlated well with the known extent of the inhibition of poly(ADP-ribose) synthesis. A radiation-sensitive line, V79- AL162 /S-10, was affected to a lesser extent than the normal cells. Cells repaired the radiation damage with which the inhibitors interacted within 1 hr, a process that has similar kinetics to what is observed when a postirradiation treatment with hypertonic buffer is used [H. Utsumi and M. M. Elkind , Radiat . Res. 77, 346-360 (1979)]. However, the sectors of damage affected by inhibitors of poly(ADP-ribose) synthesis and hypertonic buffer do not entirely overlap. The inhibitor nicotinamide enhanced the killing mainly of late S-phase cells and did not affect cells at the G1/S border. It is concluded that the repair process(es) involving poly(ADP-ribose) synthesis is important for cell survival in repair-competent cells and that the radiation-sensitive cells that were examined are partially deficient in a repair pathway in which poly(ADP-ribose) participates.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 4-Aminobenzoic Acid / pharmacology
  • Animals
  • Benzamides / pharmacology
  • Cell Line
  • Cell Survival / drug effects
  • Cell Survival / radiation effects*
  • Cricetinae
  • Cricetulus
  • Niacinamide / analogs & derivatives
  • Niacinamide / pharmacology
  • Nucleoside Diphosphate Sugars / biosynthesis*
  • Nucleotidyltransferases / antagonists & inhibitors*
  • Poly Adenosine Diphosphate Ribose / biosynthesis*
  • Poly(ADP-ribose) Polymerases
  • Pyrazinamide / pharmacology
  • Radiation-Sensitizing Agents / pharmacology*
  • ortho-Aminobenzoates / pharmacology
  • para-Aminobenzoates


  • Benzamides
  • Nucleoside Diphosphate Sugars
  • Radiation-Sensitizing Agents
  • ortho-Aminobenzoates
  • para-Aminobenzoates
  • Niacinamide
  • Poly Adenosine Diphosphate Ribose
  • Pyrazinamide
  • benzamide
  • 4-aminobenzamide
  • 3-aminobenzamide
  • Poly(ADP-ribose) Polymerases
  • Nucleotidyltransferases
  • anthranilamide
  • 4-Aminobenzoic Acid
  • N-methylnicotinamide