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Inhibition of homologous recombination by treatment with BVDU (brivudin) or by RAD51 silencing increases chromosomal damage induced by bleomycin in mismatch repair-deficient tumour cells
- Source :
- Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. 664:39-47
- Publication Year :
- 2009
- Publisher :
- Elsevier BV, 2009.
-
Abstract
- Mismatch repair (MMR) has been shown to control homologous recombination (HR) by aborting strand exchange between divergent sequences. We previously demonstrated that MMR-deficient tumour cells are more resistant to chromosomal damage induced by bleomycin (BLM) during the G(2) phase, likely due to the lack of the MMR inhibitory effect on HR. Aim of this study was to investigate whether inhibition of HR by the nucleoside analogue BVDU [(E)-5(2-bromovinyl)-2'-deoxyuridine, brivudin], or silencing of genes involved in HR function, might affect sensitivity of MMR-deficient turnout cells to DNA damage induced by BLM in G(2). The results indicated that BVDU increased chromatid damage and DNA double strand breaks induced by BLM only in MMR-deficient MT-1, HL-60R, HCT116 cells, which are more resistant to BLM with respect to MMR-proficient TK-6, HL-60S and HCT116/3-6 lines. Silencing of RAD51,a key component of HR, increased sensitivity of MMR-deficient HCT-15 cells to BLM clastogenicity; in this case combined treatment with BVDU had no additional effect. Similarly, treatment with BVDU did not affect BLM clastogenicity, in CAPAN-1 cells, characterized by a defective HR due to BRCA2 mutations. Conversely, BVDU increased chromatid breaks induced by BLM in HCT-15 cells transiently silenced for DNA-PK catalytic subunit, which plays a key role in non-homologous end joining. The BVDU-mediated increase of chromatid breaks in MMR-deficient cells did not depend on its previously reported inhibitory effect on poly(ADP-ribose) polymerase (PARP). In fact, it was observed also in cells stably silenced for PARP-1, which is responsible for most of cellular PARP activity. These data support the suggestion that the higher sensitivity of MMR-proficient versus MMR-deficient cells to BLM-induced chromatid breaks in the G(2) phase is a consequence of the inhibition of HR by MMR. In MMR-deficient cells, BVDU attenuates the repair of BLM-induced DSBs and this is likely to occur via inhibition of HR. (c) 2009 Elsevier B.V. All rights reserved.
- Subjects :
- congenital, hereditary, and neonatal diseases and abnormalities
DNA damage
Health, Toxicology and Mutagenesis
Poly ADP ribose polymerase
RAD51
Gene Expression
HL-60 Cells
Chromatids
Poly(ADP-ribose) Polymerase Inhibitors
Biology
PARP1
DNA Mismatch Repair
Poly (ADP-Ribose) Polymerase Inhibitor
Mismatch repair
Bleomycin
Cell Line, Tumor
Genetics
Chromosomes, Human
Humans
DNA Breaks, Double-Stranded
Gene Silencing
Homologous recombination
RNA, Small Interfering
Molecular Biology
DNA Primers
Recombination, Genetic
Base Sequence
Models, Genetic
Settore BIO/13
Molecular biology
digestive system diseases
Brivudin
Bromodeoxyuridine
DNA mismatch repair
Chromatid
Rad51 Recombinase
DNA Damage
Subjects
Details
- ISSN :
- 00275107
- Volume :
- 664
- Database :
- OpenAIRE
- Journal :
- Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
- Accession number :
- edsair.doi.dedup.....0980b4e6a32456a83c51b4f01d9f6a13