title: Inhibition of autophagy with chloroquine potentiates carfilzomib-induced apoptosis in myeloma cells in vitro and in vivo.
abstract: The proteasome inhibitor bortezomib is now the cornerstone of combination therapy of multiple myeloma (MM). Carfilzomib, a second-generation inhibitor, has shown a substantial benefit vs bortezomib in combination regimes. Here we have analyzed in detail the mechanism of cell death induced by carfilzomib and its crosstalk with autophagy and applied the results to the in vivo treatment of MM in a mouse model. Carfilzomib induced apoptosis essentially by the intrinsic pathway, through the up-regulation of Puma and Noxa proteins followed by the interaction of Puma, Noxa and Bim with Bax and of Noxa with Bak. Carfilzomib also produces an increase in the formation of autophagosomes but, as apoptosis progresses, autophagy is disrupted, probably owing to Beclin 1 and p62 inactivation. Cotreatment with chloroquine, which blocks autophagy, strongly potentiated apoptosis in vitro and in vivo. Accordingly, combination therapy with carfilzomib plus chloroquine was highly effective in the treatment of MM in a mouse xenograft model. Chloroquine also enhanced carfilzomib-induced calreticulin exposure in MM cells undergoing apoptosis, increasing the immunogenic ability of carfilzomib. These results support design of trials combining carfilzomib with chloroquine to improve MM therapy.
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Vidal
authors: V
authors: Jarauta
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Paula
authors: P
authors: Jaime
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Oscar
authors: O
authors: Gonzalo
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Diego
authors: D
authors: de Miguel
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Ariel
authors: A
authors: Ramírez-Labrada
authors: Servicio de Inmunología, Hospital Universitario Lozano Blesa, Universidad de Zaragoza, Zaragoza, Spain.
authors: Luis
authors: L
authors: Martínez-Lostao
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Alberto
authors: A
authors: Anel
authors: Fundación ARAID and Biomedical Research Centre of Aragón (CIBA), Zaragoza, Spain.
authors: Julián
authors: J
authors: Pardo
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain.
authors: Isabel
authors: I
authors: Marzo
authors: Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain. Electronic address: jnaval@unizar.es.
authors: Javier
authors: J
authors: Naval
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1 / Q000378:metabolism; D037282:Calreticulin / Q000378:metabolism; D045744:Cell Line, Tumor; D002738:Chloroquine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D006801:Humans; D008819:Mice, Nude; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D009842:Oligopeptides / Q000494:pharmacology*; D061988:Proteasome Inhibitors / Q000494:pharmacology*; D000071456:Sequestosome-1 Protein / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D023041:Xenograft Model Antitumor Assays
chemical_list: D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; C576483:CALR protein, human; D037282:Calreticulin; D009842:Oligopeptides; D061988:Proteasome Inhibitors; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; C524865:carfilzomib; D002738:Chloroquine
keywords: Apoptosis; Autophagy; Carfilzomib; Immunogenic cell death; Myeloma