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Mutations induced by dacarbazine activated with cytochrome P-450
A Mudipalli1, S S Nadadur, A E Maccubbin
1Grace Cancer Drug Center, Department of Experimental Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263.
Mutation Research
|March 1, 1995
Summary
The antitumor drug dacarbazine (DTIC) causes DNA mutations, including substitutions and deletions, through its metabolites. This study identified specific DNA sequences as mutational hotspots, crucial for understanding DTIC
Area of Science:
- Molecular Toxicology
- Genetics
- Cancer Research
Background:
- Antitumor drug dacarbazine (DTIC) is known to be mutagenic.
- DTIC's mutagenicity arises from DNA alkylation by its metabolites, processed by the mixed-function oxidase system.
Purpose of the Study:
- To investigate the base and sequence specificity of dacarbazine (DTIC)-induced mutagenesis.
- To characterize the types of mutations induced by DTIC in a specific DNA sequence.
Main Methods:
- An in vitro shuttle vector assay using the pSP189 plasmid.
- Treatment of the plasmid with DTIC in a reconstituted cytochrome P-450 system with NADPH.
- Sequencing of the SupF tRNA gene insert after replication in human Ad 293 cells and amplification in bacteria.
Main Results:
- DTIC-induced mutagenesis was dependent on the cytochrome P-450 system and NADPH.
- Mutations included single base substitutions (35%), deletions (30.5%), insertions (19.4%), and large deletions (13.8%).
- Specific base pairs (108 and 127) in the SupF tRNA were identified as mutational hotspots.
Conclusions:
- Dacarbazine (DTIC) induces a spectrum of mutations in a sequence-specific manner.
- The study highlights specific mutational hotspots, providing insights into DTIC's genotoxic mechanisms.
- Understanding these mechanisms is vital for cancer therapy and drug safety.