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Nucleic Acids Res. 1991 June 25; 19(12): 3295–3300.
PMCID: PMC328325

Camptothecin cytotoxicity in mammalian cells is associated with the induction of persistent double strand breaks in replicating DNA.


Camptothecin is a specific topoisomerase I poison and is highly cytotoxic to eukaryotic cells. In the present study, we show, using a pulse field gel electrophoresis assay, that camptothecin induces DNA double strand breaks (DSBs) specifically in newly replicated DNA. Camptothecin induces these replication associated DNA DSBs in a dose-dependent manner. At levels of the drug which are toxic to the cell, these breaks are long-lived, and still measurable 24 hr after treatment. Both camptothecin induced DSBs and cytotoxicity are prevented by co-exposure with aphidicolin--a result which indicates that ongoing DNA synthesis is required for the production of DNA DSBs and cell killing. It has been proposed that camptothecin toxicity involves an interaction between the replication machinery and a drug-mediated topoisomerase I-DNA cleavable complex. The present work indicates, for the first time in mammalian cellular DNA, that one possible outcome of this interaction is a replication-associated DSB, a lesion which is likely to be highly cytotoxic.

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Selected References

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  • Liu LF. DNA topoisomerase poisons as antitumor drugs. Annu Rev Biochem. 1989;58:351–375. [PubMed]
  • Nelson EM, Tewey KM, Liu LF. Mechanism of antitumor drug action: poisoning of mammalian DNA topoisomerase II on DNA by 4'-(9-acridinylamino)-methanesulfon-m-anisidide. Proc Natl Acad Sci U S A. 1984 Mar;81(5):1361–1365. [PubMed]
  • Hsiang YH, Hertzberg R, Hecht S, Liu LF. Camptothecin induces protein-linked DNA breaks via mammalian DNA topoisomerase I. J Biol Chem. 1985 Nov 25;260(27):14873–14878. [PubMed]
  • Horwitz MS, Horwitz SB. Intracellular degradation of HeLa and adenovirus type 2 DNA induced by camptothecin. Biochem Biophys Res Commun. 1971 Nov 5;45(3):723–727. [PubMed]
  • Hsiang YH, Liu LF. Identification of mammalian DNA topoisomerase I as an intracellular target of the anticancer drug camptothecin. Cancer Res. 1988 Apr 1;48(7):1722–1726. [PubMed]
  • Covey JM, Jaxel C, Kohn KW, Pommier Y. Protein-linked DNA strand breaks induced in mammalian cells by camptothecin, an inhibitor of topoisomerase I. Cancer Res. 1989 Sep 15;49(18):5016–5022. [PubMed]
  • Hsiang YH, Lihou MG, Liu LF. Arrest of replication forks by drug-stabilized topoisomerase I-DNA cleavable complexes as a mechanism of cell killing by camptothecin. Cancer Res. 1989 Sep 15;49(18):5077–5082. [PubMed]
  • Kessel D, Bosmann HB, Lohr K. Camptothecin effects on DNA synthesis in murine leukemia cells. Biochim Biophys Acta. 1972 May 10;269(2):210–216. [PubMed]
  • Li LH, Fraser TJ, Olin EJ, Bhuyan BK. Action of camptothecin on mammalian cells in culture. Cancer Res. 1972 Dec;32(12):2643–2650. [PubMed]
  • Heck MM, Hittelman WN, Earnshaw WC. Differential expression of DNA topoisomerases I and II during the eukaryotic cell cycle. Proc Natl Acad Sci U S A. 1988 Feb;85(4):1086–1090. [PubMed]
  • D'Arpa P, Beardmore C, Liu LF. Involvement of nucleic acid synthesis in cell killing mechanisms of topoisomerase poisons. Cancer Res. 1990 Nov 1;50(21):6919–6924. [PubMed]
  • Snapka RM. Topoisomerase inhibitors can selectively interfere with different stages of simian virus 40 DNA replication. Mol Cell Biol. 1986 Dec;6(12):4221–4227. [PMC free article] [PubMed]
  • Avemann K, Knippers R, Koller T, Sogo JM. Camptothecin, a specific inhibitor of type I DNA topoisomerase, induces DNA breakage at replication forks. Mol Cell Biol. 1988 Aug;8(8):3026–3034. [PMC free article] [PubMed]
  • Shin CG, Snapka RM. Exposure to camptothecin breaks leading and lagging strand simian virus 40 DNA replication forks. Biochem Biophys Res Commun. 1990 Apr 16;168(1):135–140. [PubMed]
  • Denko N, Giaccia A, Peters B, Stamato TD. An asymmetric field inversion gel electrophoresis method for the separation of large DNA molecules. Anal Biochem. 1989 Apr;178(1):172–176. [PubMed]
  • Stamato TD, Denko N. Asymmetric field inversion gel electrophoresis: a new method for detecting DNA double-strand breaks in mammalian cells. Radiat Res. 1990 Feb;121(2):196–205. [PubMed]
  • Shibuya ML, Buddenbaum WE, Don AL, Utsumi H, Suciu D, Kosaka T, Elkind MM. Amsacrine-induced lesions in DNA and their modulation by novobiocin and 2,4-dinitrophenol. Cancer Res. 1991 Jan 15;51(2):573–580. [PubMed]
  • Ager DD, Dewey WC. Calibration of pulsed field gel electrophoresis for measurement of DNA double-strand breaks. Int J Radiat Biol. 1990 Aug;58(2):249–259. [PubMed]
  • Frankenberg D, Frankenberg-Schwager M, Blöcher D, Harbich R. Evidence for DNA double-strand breaks as the critical lesions in yeast cells irradiated with sparsely or densely ionizing radiation under oxic or anoxic conditions. Radiat Res. 1981 Dec;88(3):524–532. [PubMed]
  • Resnick MA, Martin P. The repair of double-strand breaks in the nuclear DNA of Saccharomyces cerevisiae and its genetic control. Mol Gen Genet. 1976 Jan 16;143(2):119–129. [PubMed]
  • Jeggo PA, Kemp LM. X-ray-sensitive mutants of Chinese hamster ovary cell line. Isolation and cross-sensitivity to other DNA-damaging agents. Mutat Res. 1983 Dec;112(6):313–327. [PubMed]
  • Degrassi F, De Salvia R, Tanzarella C, Palitti F. Induction of chromosomal aberrations and SCE by camptothecin, an inhibitor of mammalian topoisomerase I. Mutat Res. 1989 Mar;211(1):125–130. [PubMed]
  • Eng WK, Faucette L, Johnson RK, Sternglanz R. Evidence that DNA topoisomerase I is necessary for the cytotoxic effects of camptothecin. Mol Pharmacol. 1988 Dec;34(6):755–760. [PubMed]
  • Nitiss J, Wang JC. DNA topoisomerase-targeting antitumor drugs can be studied in yeast. Proc Natl Acad Sci U S A. 1988 Oct;85(20):7501–7505. [PubMed]

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