title: Synergistic proapoptotic activity of recombinant TRAIL plus the Akt inhibitor Perifosine in acute myelogenous leukemia cells.
abstract: To potentiate the response of acute myelogenous leukemia (AML) cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity, we have examined the efficacy of a combination with perifosine, a novel phosphatidylinositol-3-kinase (PI3K)/Akt signaling inhibitor. The rationale for using such a combination is that perifosine was recently described to increase TRAIL-R2 receptor expression and decrease the cellular FLICE-inhibitory protein (cFLIP) in human lung cancer cell lines. Perifosine and TRAIL both induced cell death by apoptosis in the THP-1 AML cell line, which is characterized by constitutive PI3K/Akt activation, but lacks functional p53. Perifosine, at concentrations below IC(50), dephosphorylated Akt and increased TRAIL-R2 levels, as shown by Western blot, reverse transcription-PCR, and flow cytometric analysis. Perifosine also decreased the long isoform of cFLIP (cFLIP-L) and the X-linked inhibitor of apoptosis protein (XIAP) expression. Perifosine and TRAIL synergized to activate caspase-8 and induce apoptosis, which was blocked by a caspase-8-selective inhibitor. Up-regulation of TRAIL-R2 expression was dependent on a protein kinase Calpha/c-Jun-NH(2)-kinase 2/c-Jun signaling pathway activated by perifosine through reactive oxygen species production. Perifosine also synergized with TRAIL in primary AML cells displaying constitutive activation of the Akt pathway by inducing apoptosis, Akt dephosphorylation, TRAIL-R2 up-regulation, cFLIP-L and XIAP down-regulation, and c-Jun phosphorylation. The combined treatment negatively affected the clonogenic activity of CD34(+) cells from patients with AML. In contrast, CD34(+) cells from healthy donors were resistant to perifosine and TRAIL treatment. Our findings suggest that the combination of perifosine and TRAIL might offer a novel therapeutic strategy for AML.
authors.affiliation: Servizio di Immunoematologia e Trasfusionale, Policlinico S. Orsola-Malpighi, Università di Bologna, Italy.
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Tazzari
authors.forename: Giovanna
authors.initials: G
authors.lastname: Tabellini
authors.forename: Francesca
authors.initials: F
authors.lastname: Ricci
authors.forename: Veronica
authors.initials: V
authors.lastname: Papa
authors.forename: Roberta
authors.initials: R
authors.lastname: Bortul
authors.forename: Francesca
authors.initials: F
authors.lastname: Chiarini
authors.forename: Camilla
authors.initials: C
authors.lastname: Evangelisti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Martinelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Bontadini
authors.forename: Lucio
authors.initials: L
authors.lastname: Cocco
authors.forename: James A
authors.initials: JA
authors.lastname: McCubrey
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Martelli
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000032:analysis / Q000037:antagonists & inhibitors; D053181:Caspase 8 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D006412:Hematopoietic Stem Cells / Q000187:drug effects; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy*; D048056:Mitogen-Activated Protein Kinase 9 / Q000502:physiology; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors*; D016755:Proto-Oncogene Proteins c-jun / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000032:analysis / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000032:analysis / Q000037:antagonists & inhibitors
chemical_list: D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D016755:Proto-Oncogene Proteins c-jun; D017382:Reactive Oxygen Species; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; D051636:X-Linked Inhibitor of Apoptosis Protein; D010767:Phosphorylcholine; C105905:perifosine; D048056:Mitogen-Activated Protein Kinase 9; D051057:Proto-Oncogene Proteins c-akt; D011493:Protein Kinase C; D053181:Caspase 8