title: Mechanisms of tolerance to DNA damaging therapeutic drugs.
abstract: The cytotoxic effect of many anticancer drugs relies on their ability to damage DNA. Drug resistance can be associated with the ability to remove potentially lethal DNA lesions. DNA damage tolerance offers an alternative route to resistance. In a drug-tolerant cell, persistent DNA damage has become uncoupled from cell death. Tolerance to some DNA damaging drugs is accompanied by inactivation of the cell's DNA mismatch repair pathway. This is widely acknowledged as the mechanism underlying resistance to methylating agents and to 6-thioguanine which produce structurally similar types of DNA damage. Defects in mismatch repair are also associated with resistance to numerous drugs that produce a wide variety of structurally diverse DNA lesions. Here I consider possible mechanisms by which mismatch repair might influence drug resistance and the extent to which loss of mismatch repair might be considered to confer a multidrug resistance phenotype.
authors.affiliation: Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire, EN6 3LD, UK. karran@icrf.icnet.uk
authors.forename: P
authors.initials: P
authors.lastname: Karran
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000378:metabolism / Q000494:pharmacology*; D020137:Base Pair Mismatch / Q000235:genetics; D004249:DNA Damage / Q000187:drug effects* / Q000235:genetics*; D019175:DNA Methylation; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000187:drug effects / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans
chemical_list: D016588:Anticarcinogenic Agents