Recombination phenotypes of the NCI-60 collection of human cancer cells
1 Department of Toxicology, University of Kentucky, Lexington, KY, USA
2 Current address: Department of Medicine, Division of Hematology and Oncology, Vanderbilt University, Nashville, TN, USA
3 Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA
4 Department of Biostatistics, University of Kentucky, Lexington, KY, USA
5 Department of Microbiology, Immunology, and Molecular Genetics, Markey Cancer Center, University of Kentucky, Lexington, KY, USA
BMC Molecular Biology 2011, 12:23 doi:10.1186/1471-2199-12-23Published: 17 May 2011
The NCI-60 is a collection of tumor cell lines derived from a variety of human adult cancer tissue types and is commonly used for genetic analysis and screening of potential chemotherapeutic agents. We wanted to understand the contributions of specific mechanisms of genomic instability to the etiology of cancers represented by the NCI-60.
We screened the NCI-60 for dysregulated homologous recombination by using the gene cluster instability (GCI) assay we pioneered, and for defects in base excision repair by sensitivity to 5-hydroxymethyl-2'-deoxyuridine (hmdUrd). We identified subsets of the NCI-60 lines that either displayed the characteristic molecular signature of GCI or were sensitive to hmdUrd. With the exception of the NCI-H23 lung cancer line, these phenotypes were not found to overlap. None of the lines examined in either subset exhibited significant changes in the frequency of sister chromatid exchanges (SCE), neither did any of the lines in either subset exhibit microsatellite instability (MSI) indicative of defects in DNA mismatch repair.
Gene cluster instability, sensitivity to hmdUrd and sister chromatid exchange are mechanistically distinct phenomena. Genomic instability in the NCI-60 appears to involve only one mechanism of instability for each individual cell line.