title: STI571 reduces NER activity in BCR/ABL-expressing cells.
abstract: Nucleotide-excision repair (NER) is the most versatile mechanism of DNA repair, recognizing and dealing with a variety of helix-distorting lesions, such as the UV-induced photoproducts cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) photoproducts. We investigated the influence of an anticancer drug, STI571, on the efficacy of NER in removing UV-induced DNA damage. STI571 is used mostly in the treatment of chronic myeloid leukemia and inhibits activity of the BCR/ABL oncogenic tyrosine kinase, which is a hallmark of this disease. NER activity was examined in the BCR/ABL-expressing cell lines K562 and BV173 of myeloid and lymphoid origin, respectively, as well as in CCRF-CEM cells, which do not express BCR/ABL. A murine myeloid parental 32D cell line and its counterpart transfected with the BCR/ABL gene were also tested. NER activity was assessed in the cell extracts by use of an UV-irradiated plasmid as a substrate and by a modified single-cell gel electrophoresis (comet) assay on UV-treated nucleoids. Additionally, quantitative PCR was performed to evaluate the efficacy of the removal of UV-induced lesions from the p53 gene by intact cells. Results obtained from these experiments indicate that STI571 decreases the efficacy of NER in leukemic cells expressing BCR/ABL. Therefore, STI571 may overcome the drug resistance associated with increased DNA repair in BCR/ABL-positive leukemias.
authors.affiliation: Department of Molecular Genetics, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Sliwinski
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Czechowska
authors.forename: Janusz
authors.initials: J
authors.lastname: Szemraj
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Morawiec
authors.forename: Tomasz
authors.initials: T
authors.lastname: Skorski
authors.forename: Janusz
authors.initials: J
authors.lastname: Blasiak
mesh_terms: D000818:Animals; D001549:Benzamides; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D020552:Comet Assay; D004260:DNA Repair; D006801:Humans; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics*; D051379:Mice; D010879:Piperazines / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D011743:Pyrimidines / Q000494:pharmacology*
chemical_list: D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate