title: Proteasome inhibitor, bortezomib, potently inhibits the growth of adult T-cell leukemia cells both in vivo and in vitro.
abstract: Adult T-cell leukemia (ATL) is a fatal neoplasm derived from CD4-positive T-lymphocytes, and regardless of intensive chemotherapy, its mean survival time is less than 1 year. Nuclear factor-kappaB (NF-kappaB) activation was reported in HTLV-I associated cells, and has been implicated in oncogenesis and resistance to anticancer agents and apoptosis. We studied the effect of a proteasome inhibitor, bortezomib (formerly known as PS-341), on ATL cells in vitro and in vivo. Bortezomib could inhibit the degradation of IkappaBalpha in ATL cells, resulting in suppression of NF-kappaB and induction of cell death in ATL cells in vitro. Susceptibilities to bortezomib were well correlated with NF-kappaB activation, suggesting that suppression of the NF-kappaB pathway was implicated in the cell death induced by bortezomib. Although the majority of the cell death was apoptosis, necrotic cell death was observed in the presence of a caspase inhibitor, z-VAD-fmk. When bortezomib was administered into SCID mice bearing tumors, it suppressed tumor growth in vivo, showing that bortezomib was effective against ATL cells in vivo. These studies revealed that bortezomib is highly effective against ATL cells in vitro and in vivo by induction of apoptosis, and its clinical application might improve the prognosis of patients with this fatal disease.
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Satou
authors.forename: K
authors.initials: K
authors.lastname: Nosaka
authors.forename: Y
authors.initials: Y
authors.lastname: Koya
authors.forename: J-I
authors.initials: JI
authors.lastname: Yasunaga
authors.forename: S
authors.initials: S
authors.lastname: Toyokuni
authors.forename: M
authors.initials: M
authors.lastname: Matsuoka
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001897:Boronic Acids / Q000494:pharmacology; D000069286:Bortezomib; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000187:drug effects; D015490:HTLV-I Infections / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000188:drug therapy* / Q000473:pathology*; D051379:Mice; D016513:Mice, SCID; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000378:metabolism; D009368:Neoplasm Transplantation; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D011719:Pyrazines / Q000494:pharmacology; D014183:Transplantation, Heterologous
chemical_list: D000970:Antineoplastic Agents; D001897:Boronic Acids; D009097:Multienzyme Complexes; D016328:NF-kappa B; D011480:Protease Inhibitors; D011719:Pyrazines; D000069286:Bortezomib; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex