Nucleic Acids Research, Vol 25, Issue 8 1516-1522, Copyright © 1997 by Oxford University Press
C Bailly, A Kenani and MJ Waring
The antitumour antibiotics bleomycin and actinomycin are commonly used
therapeutically in combination. One causes metal ion- and oxygen- dependent
oxidative damage to DNA, while the other acts at the level of DNA via
intercalation of its phenoxazone chromophore and probable inhibition of
topoisomerases. Both drugs bind and/or cleave DNA primarily at
guanine-containing sequences, which could lead to mutual interference.
Using three different restriction fragments we show that binding of
actinomycin to DNA causes major alterations in the sequence specificity of
bleomycin.Fe-mediated cleavage, including the appearance of new cleavage
sites and the suppression of others. The subtle sequence-dependence of the
interference is illustrated by the different effects of actinomycin on DNA
cleavage by the deglycobleomycin.Fe complex. Actinomycin sharply decreases
the extent of cleavage at GpC sites by both bleomycin and deglycobleomycin
whereas cleavage at GpT sites is much less affected, while novel cleavage
sites are generated at GpA, ApT and, to a lesser extent, TpT steps. A
dramatic increase in bleomycin.Fe cutting at GpA is barely detectable with
deglycobleomycin.Fe, confirming that the carbohydrate moiety of bleomycin
is important for DNA recognition. The results contribute to a better
understanding of how two individually well-characterized small molecules
interact simultaneoulsy with specific sequences in DNA and as such assist
clarification of the principles governing drug-DNA recognition.
ARTICLES
Altered cleavage of DNA sequences by bleomycin and its deglycosylated derivative in the presence of actinomycin
INSERM Unite 124 et Laboratoire de Phamracologie Antitumorale Moleculaire du Centre Oscar Lambret, Place de Verdun, 59045 Lille, France. bailly@lille.inserm.fr
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
K. Swales, S. Kakizaki, Y. Yamamoto, K. Inoue, K. Kobayashi, and M. Negishi Novel CAR-mediated Mechanism for Synergistic Activation of Two Distinct Elements within the Human Cytochrome P450 2B6 Gene in HepG2 Cells J. Biol. Chem., February 4, 2005; 280(5): 3458 - 3466. [Abstract] [Full Text] [PDF] |
||||
