Grant-in-Aid for Challenging Exploratory Research
Using the CRISPR/Cas9 genome editing technique, we established HeLa clones carrying MSH2 variations; G674R, G674D and G674A, those were reported in Lynch syndrome (LS) patients. These clones showed hyper resistance to MNU, with a characteristic feature of MMR-deficiency. And the mutation frequencies observed at the HPRT locus were uniformly elevated in these clones. Another hallmark of MMR deficiency is microsatellite instability (MSI) that is known to widely and drastically undergo length changes in MMR-defective tumors. However, microsatellite alterations in these clones were generally modest. Alterations in dinucleotide microsatellites were rare and, in all cases, within 6-bp, which corresponds to Type A instability that we have previously reported in Msh2-deficient mice. Mononucleotide repeats were stable in the clones. Accordingly, molecular defects, not yet discerned, should underlie genomic instability observed in MSI+ human tumors including ones developed in LS patients.
Free Radic Biol Med
Attribution of KAKENHI