Abstract
Loss of mismatch repair (MMR) leads to a complex mutator phenotype that appears to drive the development of a subset of colon cancers. Here we show that MMR-deficient tumour cell lines are highly sensitive to the toxic effects of thymidine relative to MMR-proficient lines. This sensitivity was not a direct consequence of MMR deficiency or alterations of DNA precursor metabolism. Instead, MMR-defective tumour cell lines are also defective in homologous recombination repair (HRR) induced by DNA double-strand breaks. Furthermore, a frameshift mutation of the human RAD51 paralog XRCC2 found in the MMR-deficient uterine tumour cell line SKUT-1 can confer thymidine sensitivity when introduced into a MMR-proficient line. Like other cells with defective XRCC2, SKUT-1 is sensitive to mitomycin C, and MMR-proficient cells expressing the mutant XRCC2 allele become more sensitive to this agent. These data suggest that the thymidine sensitivity of MMR-deficient tumour cell lines may be a consequence of defects in the HRR pathway. The increased thymidine sensitivity and the loss of an important pathway for the repair of DNA double-strand breaks create new opportunities for therapies directed specifically against this subset of tumours.
Original language | English (US) |
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Pages (from-to) | 2189-2200 |
Number of pages | 12 |
Journal | Human Molecular Genetics |
Volume | 11 |
Issue number | 18 |
DOIs | |
State | Published - Sep 1 2002 |
Externally published | Yes |
ASJC Scopus subject areas
- Molecular Biology
- Genetics
- Genetics(clinical)