Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1999-3-25
pubmed:abstractText
To test the hypothesis whether DNA polymerases acquire mutator properties during tumor development (mutator hypothesis), we examined DNA polymerase delta mRNA in 6 colon cancer cell lines (DLD-1, HCT116, SW48, HT29, SW480 and SW620) and 7 sporadic human colorectal cancers. For analysis we used amplification of cDNA by polymerase chain reaction, single-strand conformation polymorphism and sequencing techniques. In 5 of the cell lines, 9 mutations leading to changes of the amino acid sequence of DNA polymerase delta were detected. Most mutations were found in the cell lines DLD-1, HCT116 and SW48 for which defects in mismatch repair genes had been identified previously. In the majority of cases, wild type and mutated sequences were present. In 2 cell lines (HCT116 and SW48), a single-nucleotide deletion occurred at the same position. This resulted in a premature termination codon by which the DNA interaction domain of the enzyme was eliminated. Furthermore, sequence deviations were found in the tumor tissues of 4 colon cancer patients. Wild-type and altered sequences were present simultaneously. The deviations included missense mutations (2 cases) and silent mutations (2 cases). The missense mutations and one of the silent mutations were found in normal mucosa as well. In addition, the mutation clustered region of a tumor suppressor gene, often found to be defective in colon cancer, the adenomatous polyposis coli (APC) gene, was investigated in surgical specimens and cell lines. One carcinoma and 2 cell lines exhibited amino acid changes in both the DNA polymerase delta gene and in the mutation clustered region of the APC gene. Since most of the mutations detected in the DNA polymerase delta mRNA are likely to alter the structure of the protein, the enzyme is expected to be functionally impaired. In particular, copying fidelity might be decreased, thus contributing to the high mutation rate observed in colorectal cancer.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0020-7136
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
80
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
919-29
pubmed:dateRevised
2007-7-24
pubmed:meshHeading
pubmed-meshheading:10074927-Aged, pubmed-meshheading:10074927-Amino Acid Substitution, pubmed-meshheading:10074927-Base Sequence, pubmed-meshheading:10074927-Carcinoma, pubmed-meshheading:10074927-Colonic Neoplasms, pubmed-meshheading:10074927-Colorectal Neoplasms, pubmed-meshheading:10074927-DNA, Complementary, pubmed-meshheading:10074927-DNA Mutational Analysis, pubmed-meshheading:10074927-DNA Polymerase III, pubmed-meshheading:10074927-DNA Repair, pubmed-meshheading:10074927-Female, pubmed-meshheading:10074927-Genes, APC, pubmed-meshheading:10074927-Humans, pubmed-meshheading:10074927-Male, pubmed-meshheading:10074927-Middle Aged, pubmed-meshheading:10074927-Molecular Sequence Data, pubmed-meshheading:10074927-Mutation, pubmed-meshheading:10074927-Neoplasm Proteins, pubmed-meshheading:10074927-Point Mutation, pubmed-meshheading:10074927-Polymerase Chain Reaction, pubmed-meshheading:10074927-Polymorphism, Single-Stranded Conformational, pubmed-meshheading:10074927-RNA, Messenger, pubmed-meshheading:10074927-RNA, Neoplasm, pubmed-meshheading:10074927-Sequence Analysis, pubmed-meshheading:10074927-Sequence Deletion, pubmed-meshheading:10074927-Sequence Homology, pubmed-meshheading:10074927-Tumor Cells, Cultured
pubmed:year
1999
pubmed:articleTitle
Detection of mutations in the DNA polymerase delta gene of human sporadic colorectal cancers and colon cancer cell lines.
pubmed:affiliation
Division of Interaction of Carcinogens with Biologial Macromolecules, German Research Center, Heidelberg.
pubmed:publicationType
Journal Article, Comparative Study