title: Proteomic analysis reveals a role for Bcl2-associated athanogene 3 and major vault protein in resistance to apoptosis in senescent cells by regulating ERK1/2 activation.
abstract: Senescence is a prominent solid tumor response to therapy in which cells avoid apoptosis and instead enter into prolonged cell cycle arrest. We applied a quantitative proteomics screen to identify signals that lead to therapy-induced senescence and discovered that Bcl2-associated athanogene 3 (Bag3) is up-regulated after adriamycin treatment in MCF7 cells. Bag3 is a member of the BAG family of co-chaperones that interacts with Hsp70. Bag3 also regulates major cell-signaling pathways. Mass spectrometry analysis of the Bag3 Complex revealed a novel interaction between Bag3 and Major Vault Protein (MVP). Silencing of Bag3 or MVP shifts the cellular response to adriamycin to favor apoptosis. We demonstrate that Bag3 and MVP contribute to apoptosis resistance in therapy-induced senescence by increasing the level of activation of extracellular signal-regulated kinase1/2 (ERK1/2). Silencing of either Bag3 or MVP decreased ERK1/2 activation and promoted apoptosis in adriamycin-treated cells. An increase in nuclear accumulation of MVP is observed during therapy-induced senescence and the shift in MVP subcellular localization is Bag3-dependent. We propose a model in which Bag3 binds to MVP and facilitates MVP accumulation in the nucleus, which sustains ERK1/2 activation. We confirmed that silencing of Bag3 or MVP shifts the response toward apoptosis and regulates ERK1/2 activation in a panel of diverse breast cancer cell lines. This study highlights Bag3-MVP as an important complex that regulates a potent prosurvival signaling pathway and contributes to chemotherapy resistance in breast cancer.
authors.affiliation: From the ‡Department of Pathology, University of California San Diego, La Jolla, CA 92093;
authors.forename: Martina P
authors.initials: MP
authors.lastname: Pasillas
authors.affiliation: §Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland;
authors.forename: Sarah
authors.initials: S
authors.lastname: Shields
authors.affiliation: §Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland;
authors.forename: Rebecca
authors.initials: R
authors.lastname: Reilly
authors.affiliation: From the ‡Department of Pathology, University of California San Diego, La Jolla, CA 92093;
authors.forename: Jan
authors.initials: J
authors.lastname: Strnadel
authors.affiliation: ¶Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Duesbergweg 6, D-55099 Mainz, Germany;
authors.forename: Christian
authors.initials: C
authors.lastname: Behl
authors.affiliation: ‖Department of Chemical Physiology, the Scripps Research Institute, La, Jolla, California 92037.
authors.forename: Robin
authors.initials: R
authors.lastname: Park
authors.affiliation: ‖Department of Chemical Physiology, the Scripps Research Institute, La, Jolla, California 92037.
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.affiliation: From the ‡Department of Pathology, University of California San Diego, La Jolla, CA 92093;
authors.forename: Richard
authors.initials: R
authors.lastname: Klemke
authors.affiliation: From the ‡Department of Pathology, University of California San Diego, La Jolla, CA 92093;
authors.forename: Steven L
authors.initials: SL
authors.lastname: Gonias
authors.affiliation: From the ‡Department of Pathology, University of California San Diego, La Jolla, CA 92093; §Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland; judith.coppinger@ucd.ie.
authors.forename: Judith A
authors.initials: JA
authors.lastname: Coppinger
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D016922:Cellular Senescence / Q000502:physiology*; D004317:Doxorubicin / Q000494:pharmacology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D040901:Proteomics; D015398:Signal Transduction; D020394:Vault Ribonucleoprotein Particles / Q000378:metabolism*; D000099187:Major Vault Protein
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000903:Antibiotics, Antineoplastic; D051017:Apoptosis Regulatory Proteins; D004317:Doxorubicin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020394:Vault Ribonucleoprotein Particles; D000099187:Major Vault Protein; C414431:BAG3 protein, human; C535150:MAPK1 protein, human