title: TNF-alpha-converting enzyme (TACE/ADAM17)-dependent loss of CD30 induced by proteasome inhibition through reactive oxygen species.
abstract: Combinations with proteasome inhibitors are currently being investigated to improve the therapy of hematological malignancies. We previously found that proteasome inhibition by bortezomib failed to sensitize anti-CD30 antibody (Ab)-based lymphoma cell killing. In this study, we demonstrate in L540 Hodgkin's lymphoma cells that proteasome inhibition not only communicates apoptosis but also more rapidly causes a loss of CD30 antigen from cell membrane and a simultaneous release of soluble CD30, a targeting competitor. This shedding was catalyzed by the tumor necrosis factor (TNF)-alpha-converting enzyme (TACE, ADAM17) and blocked by the ADAM17-selective inhibitor, Ro32-7315. In parallel with CD30 shedding, bortezomib caused the generation of reactive oxygen species (ROS). As apoptosis and shedding were inhibited by the radical scavenger, N-acetyl-L-cysteine, ROS might have a pivotal function in both effects. In contrast, the pan-caspase inhibitor, zVAD-fmk, blocked bortezomib-induced apoptosis but not CD30 shedding, and Ro32-7315 blocked shedding but allowed apoptosis. This suggests independent terminal signaling pathways that are conflicting in Ab-based immunotherapy. Consequently, shedding inhibition substantially improved the synergistic antitumor efficacy of the human anti-CD30 Ab, MDX-060, and bortezomib. As proteasome inhibition also stimulated loss of TNF receptors, interleukin-6 receptor and syndecan-1 in different leukemia and lymphoma cell lines, we concluded that proteasome inhibition might impede targeted therapy against antigens susceptible to shedding.
authors.affiliation: Laboratory of Immunotherapy, Department I of Internal Medicine, University Clinic Cologne, Cologne 50924, Germany.
authors.forename: A M
authors.initials: AM
authors.lastname: Vahdat
authors.forename: K S
authors.initials: KS
authors.lastname: Reiners
authors.forename: V L
authors.initials: VL
authors.lastname: Simhadri
authors.forename: D A
authors.initials: DA
authors.lastname: Eichenauer
authors.forename: B
authors.initials: B
authors.lastname: Böll
authors.forename: A
authors.initials: A
authors.lastname: Chalaris
authors.forename: V R
authors.initials: VR
authors.lastname: Simhadri
authors.forename: K
authors.initials: K
authors.lastname: Wiegmann
authors.forename: H-W
authors.initials: HW
authors.lastname: Krell
authors.forename: S
authors.initials: S
authors.lastname: Rose-John
authors.forename: A
authors.initials: A
authors.lastname: Engert
authors.forename: E P
authors.initials: EP
authors.lastname: von Strandmann
authors.forename: H P
authors.initials: HP
authors.lastname: Hansen
mesh_terms: D051722:ADAM Proteins / Q000502:physiology*; D000072198:ADAM17 Protein; D000111:Acetylcysteine / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001897:Boronic Acids / Q000494:pharmacology*; D000069286:Bortezomib; D045744:Cell Line, Tumor; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D017730:Ki-1 Antigen / Q000032:analysis*; D061988:Proteasome Inhibitors; D011719:Pyrazines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D053668:Syndecan-1 / Q000032:analysis
chemical_list: C459386:2-(1-(hydroxycarbamoyl)-4-phenyl-3-butenyl)-2'-isobutyl-2'-(methanesulfonyl)-4-methylvalerohydrazide; D000911:Antibodies, Monoclonal; D001897:Boronic Acids; D006877:Hydroxamic Acids; D017730:Ki-1 Antigen; D061988:Proteasome Inhibitors; D011719:Pyrazines; D017382:Reactive Oxygen Species; C508241:SDC1 protein, human; D013449:Sulfonamides; D053668:Syndecan-1; D000069286:Bortezomib; C510955:iratumumab; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; D000111:Acetylcysteine