title: Hyperthermia adds to trabectedin effectiveness and thermal enhancement is associated with BRCA2 degradation and impairment of DNA homologous recombination repair.
abstract: The tetrahydroisoquinoline trabectedin is a marine compound with approved activity against human soft-tissue sarcoma. It exerts antiproliferative activity mainly by specific binding to the DNA and inducing DNA double-strand breaks (DSB). As homologous recombination repair (HRR)-deficient tumors are more susceptible to trabectedin, hyperthermia-mediated on-demand induction of HRR deficiency represents a novel and promising strategy to boost trabectedin treatment. For the first time, we demonstrate enhancement of trabectedin effectiveness in human sarcoma cell lines by heat and characterize cellular events and molecular mechanisms related to heat-induced effects. Hyperthermic temperatures (41.8 or 43°C) enhanced significantly trabectedin-related clonogenic cell death and G2/M cell cycle arrest followed by cell type-dependent induction of apoptosis or senescence. Heat combination increased accumulation of γH2AX foci as key marker of DSBs. Expression of BRCA2 protein, an integral protein of the HRR machinery, was significantly decreased by heat. Consequently, recruitment of downstream RAD51 to γH2AX-positive repair foci was almost abolished indicating relevant impairment of HRR by heat. Accordingly, enhancement of trabectedin effectiveness was significantly augmented in BRCA2-proficient cells by hyperthermia and alleviated in BRCA2 knockout or siRNA-transfected BRCA2 knockdown cells. In peripheral blood mononuclear cells isolated from sarcoma patients, increased numbers of nuclear γH2AX foci were detected after systemic treatment with trabectedin and hyperthermia of the tumor region. The findings establish BRCA2 degradation by heat as a key factor for a novel treatment strategy that allows targeted chemosensitization to trabectedin and other DNA damaging antitumor drugs by on-demand induction of HRR deficiency.
authors.affiliation: Hämatologikum of the Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany.
authors.forename: Dominique
authors.initials: D
authors.lastname: Harnicek
authors.affiliation: Department of Medicine III, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Kampmann
authors.affiliation: Department of Radiation Oncology, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Lauber
authors.affiliation: Department of Radiation Oncology, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Roman
authors.initials: R
authors.lastname: Hennel
authors.affiliation: Hämatologikum of the Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Cardoso Martins
authors.affiliation: Department of Medicine II, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Yang
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Radiation Oncology, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Belka
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Mörtl
authors.affiliation: Department of Internal Medicine, Philipps University of Marburg, Marburg, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Gallmeier
authors.affiliation: Department of Genetics, Cancer Genomics Netherlands, Erasmus Medical Center, Rotterdam, The Netherlands.|Department of Radiation Oncology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Roland
authors.initials: R
authors.lastname: Kanaar
authors.affiliation: Institute of Medical Informatics, Biostatistics, and Epidemiology, Campus Grosshadern, University of Munich, Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Mansmann
authors.affiliation: Department of Gastroenterology and Hepatology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors.forename: Tomas
authors.initials: T
authors.lastname: Hucl
authors.affiliation: Department of Medicine III, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Lindner
authors.affiliation: Department of Medicine III, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hiddemann
authors.affiliation: Department of Medicine III, University Hospital Grosshadern, University of Munich, Munich, Germany.
authors.forename: Rolf D
authors.initials: RD
authors.lastname: Issels
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D024682:BRCA2 Protein / Q000378:metabolism*; D020169:Caspases / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004149:Dioxoles / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000528:radiation effects; D006657:Histones / Q000378:metabolism; D006801:Humans; D006979:Hyperthermia, Induced; D008954:Models, Biological; D011485:Protein Binding; D021381:Protein Transport; D059748:Proteolysis / Q000187:drug effects / Q000528:radiation effects; D051135:Rad51 Recombinase / Q000378:metabolism; D059767:Recombinational DNA Repair / Q000187:drug effects* / Q000528:radiation effects*; D012509:Sarcoma / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D044005:Tetrahydroisoquinolines / Q000494:pharmacology*; D000077606:Trabectedin
chemical_list: D018906:Antineoplastic Agents, Alkylating; D024682:BRCA2 Protein; D004149:Dioxoles; D006657:Histones; D044005:Tetrahydroisoquinolines; D051135:Rad51 Recombinase; D020169:Caspases; D000077606:Trabectedin
keywords: DNA repair; hyperthermia; sarcoma; trabectedin