title: A nuclear protein complex containing high mobility group proteins B1 and B2, heat shock cognate protein 70, ERp60, and glyceraldehyde-3-phosphate dehydrogenase is involved in the cytotoxic response to DNA modified by incorporation of anticancer nucleoside analogues.
abstract: Thiopurine treatment of human leukemia cells deficient in components of the mismatch repair system (Nalm6) initiated apoptosis after incorporation into DNA, as revealed by caspase activation and terminal deoxynucleotidyl transferase-mediated nick end labeling assay. To elucidate the cellular sensor(s) responsible for recognition of DNA damage in cells with an inactive mismatch repair system, we isolated a multiprotein nuclear complex that preferentially binds DNA with thioguanine incorporated. The components of this nuclear multiprotein complex, as identified by protein mass spectroscopy, included high mobility group proteins 1 and 2 (HMGB1, HMGB2), heat shock protein HSC70, protein disulfide isomerase ERp60, and glyceraldehyde 3-phosphate dehydrogenase. The same complex was also shown to bind synthetic oligodeoxyribonucleotide duplexes containing the nonnatural nucleosides 1-beta-D-arabinofuranosylcytosine or 5-fluoro-2'-deoxyuridine. Fibroblast cell line derived from Hmgb1(-/-) murine embryos had decreased sensitivity to thiopurines, with an IC(50) 10-fold greater than Hmgb1-proficient cells (P < 0.0001) and exhibited comparable sensitivity to vincristine, a cytotoxic drug that is not incorporated into DNA. These findings indicate that the HMGB1-HMGB2-HSC70-ERp60-glyceraldehyde 3-phosphate dehydrogenase complex detects changes in DNA structure caused by incorporation of nonnatural nucleosides and is a determinant of cell sensitivity to such DNA modifying chemotherapy.
authors.affiliation: Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: Eugene Y
authors.initials: EY
authors.lastname: Krynetski
authors.forename: Natalia F
authors.initials: NF
authors.lastname: Krynetskaia
authors.forename: Marco E
authors.initials: ME
authors.lastname: Bianchi
authors.forename: William E
authors.initials: WE
authors.lastname: Evans
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D001483:Base Sequence; D037282:Calreticulin / Q000187:drug effects / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000187:drug effects / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism*; D006609:High Mobility Group Proteins / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D015448:Leukemia, B-Cell; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000187:drug effects / Q000378:metabolism*; D016196:S Phase / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D000964:Antimetabolites, Antineoplastic; D037282:Calreticulin; D018840:HSP70 Heat-Shock Proteins; D006609:High Mobility Group Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases