Strategic down-regulation of DNA polymerase beta by antisense RNA sensitizes mammalian cells to specific DNA damaging agents

Nucleic Acids Res. 1995 Oct 11;23(19):3810-5. doi: 10.1093/nar/23.19.3810.


Previously, mouse NIH 3T3 cells were stably transfected with human DNA polymerase beta (beta-pol) cDNA in the antisense orientation and under the control of a metallothionein promoter [Zmudzka, B.Z. and Wilson, S.H. (1990) Som. Cell Mol. Gen., 16, 311-320]. To assess the feasibility of enhancing the efficacy of chemotherapy by an antisense approach and to confirm a role for beta-pol in cellular DNA repair, we looked for increased sensitivity to DNA damaging agents under conditions where beta-pol is down-regulated in the antisense cell line. Such a sensitization is anticipated only where beta-pol is rate-limiting in a DNA repair pathway. A number of agents were tested: cis-diamminedichloroplatinum II (cisplatin); 1,3-bis(2-chloroethyl)-1- nitrosourea (BCNU); ionizing radiation and the radio-mimetic drug bleomycin; the bifunctional alkylating agents nitrogen mustard and L-phenylalanine mustard (melphalan); the monofunctional alkylating agent methyl methane sulfonate (MMS) and ultraviolet (UV) radiation. In the cases of cisplatin and UV radiation, a significant enhancement of cytotoxicity was observed. Damage as a result of both of these agents is thought to be repaired by the nucleotide excision repair (NER) pathway. The results suggest that, in this cell line, beta-pol is involved in and is rate-limiting in NER. We propose that down-regulation of beta-pol by antisense approaches might be used to enhance the cytotoxic effects of cisplatin and other DNA damaging chemotherapeutic agents.

Publication types

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

MeSH terms

  • 3T3 Cells
  • Animals
  • Antineoplastic Agents / pharmacology*
  • Bleomycin / pharmacology
  • Carmustine / pharmacology
  • Cell Death / drug effects
  • Cisplatin / pharmacology
  • DNA / drug effects
  • DNA / radiation effects
  • DNA Damage / drug effects*
  • DNA Polymerase I / genetics*
  • DNA Polymerase I / metabolism
  • Gene Expression Regulation / drug effects*
  • Humans
  • Mechlorethamine / pharmacology
  • Melphalan / pharmacology
  • Methyl Methanesulfonate / pharmacology
  • Mice
  • RNA, Antisense / pharmacology*
  • Transfection
  • Ultraviolet Rays
  • Zinc / pharmacology


  • Antineoplastic Agents
  • RNA, Antisense
  • Bleomycin
  • Mechlorethamine
  • DNA
  • Methyl Methanesulfonate
  • DNA Polymerase I
  • Zinc
  • Cisplatin
  • Melphalan
  • Carmustine