Induction of heat-labile sites in DNA of mammalian cells by the antitumor alkylating drug CC-1065
- Roswell Park Cancer Institute, Buffalo, NY (USA)
CC-1065 is a very potent antitumor antibiotic capable of covalent and noncovalent binding to the minor groove of naked DNA. Upon thermal treatment, covalent adducts formed between CC-1065 and DNA generate strand break. The authors have shown that this molecular damage can be detected following CC-1065 treatment of mammalian whole cells. Using alkaline sucrose gradient analysis, They observe thermally induced breakage of ({sup 14}C)thymidine-prelabeled DNA from drug-treated African green monkey kidney BSC-1 cells. Very little damage to cellular DNA by CC-1065 can be detected without first heating the drug-treated samples. CC-1065 can also generate heat-labile sites within DNA during cell lysis and heating, subsequent to the exposure of cells to drug, suggesting that a pool of free and noncovalently bound drug is available for posttreatment adduct formation. This effect was controlled for by mixing ({sup 3}H)thymidine-labeled untreated cells with the ({sup 14}C)thymidine-labeled drug-treated samples. The lowest drug dose at which heat-labile sites were detected was 3 nM CC-1065 (3 single-stranded breaks/10{sup 6} base pairs). This concentration reduced survival of BSC-1 cells to 0.1% in cytotoxicity assays. The generation of CC-1065-induced lesions in cellular DNA is time dependent (the frequency of lesions caused by a 60 nM treatment reaching a plateau at 2 h) and is not readily reversible. The results of this study demonstrate that CC-1065 does generate heat-labile sites with the cellular DNA of intact cells and suggest that a mechanism of cytotoxic action of CC-1065 involves formation of covalent adducts to DNA.
- OSTI ID:
- 5557969
- Journal Information:
- Biochemistry; (United States), Vol. 30:15; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKYLATING AGENTS
BIOLOGICAL EFFECTS
DNA
SEDIMENTATION
DNA ADDUCTS
MOLECULAR STRUCTURE
ANIMAL CELLS
ANTINEOPLASTIC DRUGS
CARBON 14 COMPOUNDS
KIDNEYS
MONKEYS
STREPTOMYCES
THYMIDINE
TIME DEPENDENCE
ADDUCTS
ANIMALS
AZINES
BACTERIA
BODY
CARBON COMPOUNDS
DRUGS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MAMMALS
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PRIMATES
PYRIMIDINES
RIBOSIDES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques