title: A novel role for DNA mismatch repair and the autophagic processing of chemotherapy drugs in human tumor cells.
abstract: DNA Mismatch repair (MMR) maintains genome integrity by correcting DNA replication errors and blocking homologous recombination between divergent DNA sequences. The MMR system also activates both checkpoint and apoptotic responses following certain types of DNA damage. In a recent study, we describe a novel role for MMR in mediating an autophagic response to 6?thioguanine (6-TG), a DNA modifying chemical. Our results show that MMR proteins (MLH1 or MSH2) are required for signaling to the autophagic pathway after exposure to 6-TG. Using PFT-alpha, a p53 inhibitor, and shRNA-mediated silencing of p53 expression, we also show that p53 plays an essential role in the autophagic pathway downstream of the MMR system. This study suggests a novel function of MMR in mediating autophagy following chemical (6-TG) DNA mismatch damage through p53 activation. Here, we present the model and the clinical implications of the role of MMR in autophagy.
authors.affiliation: Department of Radiation Oncology, Case Western Reserve University, University Hospitals Case Medical Center, Cleveland, Ohio 44106-6068, USA.
authors.forename: Xuehuo
authors.initials: X
authors.lastname: Zeng
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Kinsella
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects* / Q000235:genetics*; D052160:Benzothiazoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D053843:DNA Mismatch Repair; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D045325:HCT116 Cells; D006801:Humans; D008954:Models, Biological; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013866:Thioguanine / Q000494:pharmacology*; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D052160:Benzothiazoles; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D014050:Toluene; C121565:pifithrin; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D013866:Thioguanine