title: MEK1 inhibition sensitizes primary acute myelogenous leukemia to arsenic trioxide-induced apoptosis.
abstract: We found that MEK1 inhibitor PD184352 strikingly increased apoptosis induced by arsenic trioxide (ATO) in 21 of 25 patients with primary acute myelogenous leukemia (AML). Isobologram analysis confirmed the synergistic (13 of 25 patients) or additive (8 of 25 patients) nature of this interaction. Moreover, we demonstrated that the p53-related gene p73 is a molecular target of the combined treatment in AML blasts. Indeed, ATO modulates the expression of the p73 gene by inducing the proapoptotic and antiproliferative TAp73 and the antiapoptotic and proproliferative DeltaNp73 isoforms, thereby failing to elevate the TA/DeltaNp73 ratio. Conversely, treatment with PD184352 reduces the level of DeltaNp73 and blunts the arsenic-mediated up-regulation of DeltaNp73, thus causing an increase in the TA/DeltaNp73 ratio of dual-treated cells. High doses of ATO induced p53 accumulation in 11 of 21 patients. Combined treatment resulted in the induction of the proapoptotic p53/p73 target gene p53AIP1 (p53-regulated apoptosis-inducing protein 1) and greatly enhanced the apoptosis of treated cells.
authors.affiliation: Department of Clinical Sciences, Section of Hemato-Oncology, University of Parma, Via Gramsci 14, 43100 Parma, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Lunghi
authors.forename: Antonio
authors.initials: A
authors.lastname: Costanzo
authors.forename: Luigi
authors.initials: L
authors.lastname: Salvatore
authors.forename: Nelida
authors.initials: N
authors.lastname: Noguera
authors.forename: Laura
authors.initials: L
authors.lastname: Mazzera
authors.forename: Antonio
authors.initials: A
authors.lastname: Tabilio
authors.forename: Francesco
authors.initials: F
authors.lastname: Lo-Coco
authors.forename: Massimo
authors.initials: M
authors.lastname: Levrero
authors.forename: Antonio
authors.initials: A
authors.lastname: Bonati
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000032:analysis; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D004357:Drug Synergism; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000473:pathology*; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors*; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000032:analysis; D010087:Oxides / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D025521:Tumor Suppressor Proteins
chemical_list: C120227:2-(2-chloro-4-iodophenylamino)-N-cyclopropylmethoxy-3,4-difluorobenzamide; D001152:Arsenicals; D001549:Benzamides; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010087:Oxides; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D000077237:Arsenic Trioxide