title: Combined effect of all-trans retinoic acid and arsenic trioxide in acute promyelocytic leukemia cells in vitro and in vivo.
abstract: All-trans retinoic acid (tRA) and arsenic trioxide (As(2)O(3)) induce non-cross-resistant complete clinical remission in patients with acute promyelocytic leukemia with t(15;17) translocation and target PML-RARalpha, the leukemogenic protein, by different pathways suggesting a possible therapeutic synergism. To evaluate this possibility, this study examined the effect of As(2)O(3) on tRA-induced differentiation and, conversely, the effect of tRA on As(2)O(3)-induced apoptosis. As(2)O(3) at subapoptotic concentrations (0.5 microM) decreased tRA-induced differentiation in NB4 cells but synergized with atRA to induce differentiation in tRA-resistant NB4 subclones MR-2 and R4 cells as measured by nitroblue tetrazolium reduction and tRA-inducible genes (TTGII, RARbeta, RIG-E). tRA cleaved PML-RARalpha into distinct fragments in NB4 but not in tRA-resistant MR-2 or R4 cells, whereas As(2)O(3) completely degraded PML-RARalpha in all 3 cell lines. As(2)O(3)-induced apoptosis was decreased by tRA pretreatment of NB4 cells but not of R4 cells and was associated with a strong induction of Bfl-1/A1 expression, a Bcl-2 protein family member. Severe combined immunodeficient mice bearing NB4 cells showed an additive survival effect after sequential treatment, but a toxic effect was observed after simultaneous treatment with tRA and As(2)O(3). These data suggest that combined As(2)O(3) and tRA treatment may be more effective than single agents in tRA-resistant patients. Although in vitro data do not always translate to in vivo response, toxicity and potential drug antagonism may be diminished by decreasing the concentration of As(2)O(3) when given at the same time with therapeutic levels of tRA.
authors.affiliation: Department of Medicine, Division of Medical Oncology, Mount Sinai School of Medicine, New York, NY 10029-6547, USA. jing@msvax.mssm.edu
authors.forename: Y
authors.initials: Y
authors.lastname: Jing
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Xia
authors.forename: G Q
authors.initials: GQ
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: W H
authors.initials: WH
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Waxman
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D015152:Blotting, Northern; D015153:Blotting, Western; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007942:Leukemia, Experimental / Q000188:drug therapy / Q000473:pathology; D015473:Leukemia, Promyelocytic, Acute / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D016513:Mice, SCID; D009363:Neoplasm Proteins / Q000187:drug effects; D015514:Oncogene Proteins, Fusion / Q000187:drug effects; D010087:Oxides / Q000494:pharmacology*; D015996:Survival Rate; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D001152:Arsenicals; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D010087:Oxides; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein; D014212:Tretinoin; D000077237:Arsenic Trioxide