title: Histone deacetylase inhibitors synergistically potentiate death receptor 4-mediated apoptotic cell death of human T-cell acute lymphoblastic leukemia cells.
abstract: Cell-death signaling through the pro-apoptotic tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptors, death receptor 4 (DR4) and DR5, has shown tumor-selective apoptotic activity. Here, we examine susceptibility of various leukemia cell lines (HL-60, U937, K562, CCRF-CEM, CEM-CM3, and THP-1) to an anti-DR4 agonistic monoclonal antibody (mAb), AY4, in comparison with TRAIL. While most of the leukemia cell lines were intrinsically resistant to AY4 or TRAIL alone, the two T-cell acute lymphoblastic leukemia (T-ALL) lines, CEM-CM3 and CCRF-CEM cells, underwent synergistic caspase-dependent apoptotic cell death by combination of AY4 or TRAIL with a histone deacetylase inhibitor (HDACI), either suberoylanilide hydroxamic acid (SAHA) or valproic acid (VPA). All of the combined treatments synergistically downregulated several anti-apoptotic proteins (c-FLIP, Bcl-2, Bcl-X(L), XIAP, and survivin) without significant changing the expression levels of pro-apoptotic proteins (Bax and Bak) or the receptors (DR4 and DR5). Downregulation of c-FLIP to activate caspase-8 was a critical step for the synergistic apoptosis through both extrinsic and intrinsic apoptotic pathways. Our results demonstrate that the HDACIs have synergistic effects on DR4-specific mAb AY4-mediated cell death in the T-ALL cells with comparable competence to those exerted by TRAIL, providing a new strategy for the targeted treatment of human T-ALL cells.
authors.affiliation: Department of Molecular Science and Technology, Ajou University, San5, Woncheon-dong, Yeongtong-gu, Suwon, 443-749, Korea.
authors.forename: Eun-Sil
authors.initials: ES
authors.lastname: Sung
authors.forename: Aeyung
authors.initials: A
authors.lastname: Kim
authors.forename: Joon Seong
authors.initials: JS
authors.lastname: Park
authors.forename: Junho
authors.initials: J
authors.lastname: Chung
authors.forename: Myung-Hee
authors.initials: MH
authors.lastname: Kwon
authors.forename: Yong-Sung
authors.initials: YS
authors.lastname: Kim
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation; D004357:Drug Synergism; D005434:Flow Cytometry; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism / Q000473:pathology*; D034741:RNA, Small Interfering; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism / Q000494:pharmacology; D014635:Valproic Acid / Q000494:pharmacology*; D000077337:Vorinostat
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D051034:Inhibitor of Apoptosis Proteins; D034741:RNA, Small Interfering; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; D000077337:Vorinostat; D014635:Valproic Acid; D020169:Caspases; D006655:Histone Deacetylases