title: Apo2L/TRAIL and Bcl-2-related proteins regulate type I interferon-induced apoptosis in multiple myeloma.
abstract: It has been reported that interferons (IFNs) may have antitumor activity in multiple myeloma (MM). The mechanism for their effect on MM, however, remains elusive. This study shows that IFN-alpha and -beta, but not -gamma, induce apoptosis characterized by Annexin V positivity, nuclear fragmentation and condensation, and loss of clonogenicity in 3 MM cell lines (U266, RPMI-8266, and NCI-H929), and in plasma cells from 10 patients with MM. Apo2 ligand (Apo2L, also TRAIL) induction was one of the earliest events following IFN administration in U266 cells. Treatment of these cells with TRAIL, but not with Fas agonistic antibodies, induces apoptosis. Cell death induced by IFNs and Apo2L in U266 cells was partially blocked by a dominant-negative Apo2L receptor, DR5, demonstrating the functional significance of Apo2L induction. This study shows that IFNs activate caspases and the mitochondrial-dependent apoptotic pathway, possibly mediated by Apo2L production. Thus, IFN-alpha and -beta induce cytochrome c release from mitochondria starting at 12 hours, with an amplified release seen at 48 hours. Moreover, Bid cleavage precedes the initial cytochrome c release, whereas the late, amplified cytochrome c release coincides with changes in levels of Bcl-2, Bcl-X(L), and reduction of mitochondrial membrane potential. These results link the Apo2L induction and modulation of Bcl-2 family proteins to mitochondrial dysfunction. Furthermore, IFNs and Apo2L induce cell death of CD38(+)/CD45(-/dim) plasma cells, without significant effect on nonplasma blood cells, in a caspase and Bcl-2 cleavage-dependent manner. These results warrant further clinical studies with IFNs and Apo2L in MM.
authors.affiliation: Department of Cancer Biology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Gong
authors.forename: A S
authors.initials: AS
authors.lastname: Mahmoud-Ahmed
authors.forename: A
authors.initials: A
authors.lastname: Zhou
authors.forename: E D
authors.initials: ED
authors.lastname: Hsi
authors.forename: M
authors.initials: M
authors.lastname: Hussein
authors.forename: A
authors.initials: A
authors.lastname: Almasan
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D003574:Cytochrome c Group / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009101:Multiple Myeloma / Q000473:pathology*; D010950:Plasma Cells; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*
chemical_list: D051017:Apoptosis Regulatory Proteins; D051023:BH3 Interacting Domain Death Agonist Protein; C494814:BID protein, human; D002352:Carrier Proteins; D003574:Cytochrome c Group; D007370:Interferon Type I; D008562:Membrane Glycoproteins; D019253:Proto-Oncogene Proteins c-bcl-2; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D020169:Caspases