title: Bortezomib induces autophagic death in proliferating human endothelial cells.
abstract: The proteasome inhibitor Bortezomib has been approved for the treatment of relapsed/refractory multiple myeloma (MM), thanks to its ability to induce MM cell apoptosis. Moreover, Bortezomib has antiangiogenic properties. We report that endothelial cells (EC) exposed to Bortezomib undergo death to an extent that depends strictly on their activation state. Indeed, while quiescent EC are resistant to Bortezomib, the drug results maximally toxic in EC switched toward angiogenesis with FGF, and exerts a moderate effect on subconfluent HUVEC. Moreover, EC activation state deeply influences the death pathway elicited by Bortezomib: after treatment, angiogenesis-triggered EC display typical features of apoptosis. Conversely, death of subconfluent EC is preceded by ROS generation and signs typical of autophagy, including intense cytoplasmic vacuolization with evidence of autophagosomes at electron microscopy, and conversion of the cytosolic MAP LC3 I form toward the autophagosome-associated LC3 II form. Treatment with the specific autophagy inhibitor 3-MA prevents both LC3 I/LC3 II conversion and HUVEC cell death. Finally, early removal of Bortezomib is accompanied by the recovery of cell shape and viability. These findings strongly suggest that Bortezomib induces either apoptosis or autophagy in EC; interfering with the autophagic response may potentiate the antiangiogenic effect of the drug.
authors.affiliation: Myeloma Unit, Department of Oncology, IRCCS H San Raffaele, Milan, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Belloni
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Veschini
authors.forename: Chiara
authors.initials: C
authors.lastname: Foglieni
authors.forename: Giacomo
authors.initials: G
authors.lastname: Dell'Antonio
authors.forename: Federico
authors.initials: F
authors.lastname: Caligaris-Cappio
authors.forename: Marina
authors.initials: M
authors.lastname: Ferrarini
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Ferrero
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D020533:Angiogenesis Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D001343:Autophagy / Q000187:drug effects*; D001897:Boronic Acids / Q000494:pharmacology* / Q000627:therapeutic use; D000069286:Bortezomib; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009101:Multiple Myeloma / Q000188:drug therapy / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D000970:Antineoplastic Agents; D001897:Boronic Acids; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D011480:Protease Inhibitors; D011719:Pyrazines; D017382:Reactive Oxygen Species; C025946:3-methyladenine; D005346:Fibroblast Growth Factors; D000069286:Bortezomib; D000225:Adenine