title: Coadministration of histone deacetylase inhibitors and perifosine synergistically induces apoptosis in human leukemia cells through Akt and ERK1/2 inactivation and the generation of ceramide and reactive oxygen species.
abstract: Interactions between histone deacetylase inhibitors (HDACIs) and the alkyl-lysophospholipid perifosine were examined in human leukemia cells. Coadministration of sodium butyrate, suberoylanilide hydroxamic acid (SAHA), or trichostatin with perifosine synergistically induced mitochondrial dysfunction (cytochrome c and apoptosis-inducing factor release), caspase-3 and -8 activation, apoptosis, and a marked decrease in cell growth in U937 as well as HL-60 and Jurkat leukemia cells. These events were associated with inactivation of extracellular signal-regulated kinase (ERK) 1/2 and Akt, p46 c-jun-NH2-kinase (JNK) activation, and a pronounced increase in generation of ceramide and reactive oxygen species (ROS). They were also associated with up-regulation of Bak and a marked conformational change in Bax accompanied by membrane translocation. Ectopic expression of Bcl-2 delayed but was ultimately ineffective in preventing perifosine/HDACI-mediated apoptosis. Enforced expression of constitutively active mitogen-activated protein kinase kinase (MEK) 1 or myristoylated Akt blocked HDACI/perifosine-mediated ceramide production and cell death, suggesting that MEK/ERK and Akt inactivation play a primary role in these phenomena. However, inhibition of JNK activation (e.g., by the JNK inhibitor SP600125) did not attenuate sodium butyrate/perifosine-induced apoptosis. In addition, the free radical scavenger N-acetyl-L-cysteine attenuated ROS generation and apoptosis mediated by combined treatment. Finally, the acidic sphingomyelinase inhibitor desipramine attenuated HDACI/perifosine-mediated ceramide and ROS production as well as cell death. Together, these findings indicate that coadministration of HDACIs with perifosine in human leukemia cells leads to Akt and MEK/ERK disruption, a marked increase in ceramide and ROS production, and a striking increase in mitochondrial injury and apoptosis. They also raise the possibility that combining these agents may represent a novel antileukemic strategy.
authors.affiliation: Department of Medicine, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Rahmani
authors.forename: Erin
authors.initials: E
authors.lastname: Reese
authors.forename: Yun
authors.initials: Y
authors.lastname: Dai
authors.forename: Cheryl
authors.initials: C
authors.lastname: Bauer
authors.forename: Shawn G
authors.initials: SG
authors.lastname: Payne
authors.forename: Paul
authors.initials: P
authors.lastname: Dent
authors.forename: Sarah
authors.initials: S
authors.lastname: Spiegel
authors.forename: Steven
authors.initials: S
authors.lastname: Grant
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002087:Butyrates / Q000008:administration & dosage / Q000494:pharmacology; D048708:Cell Growth Processes / Q000187:drug effects; D045744:Cell Line, Tumor; D002518:Ceramides / Q000096:biosynthesis; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006877:Hydroxamic Acids / Q000008:administration & dosage / Q000494:pharmacology; D007938:Leukemia / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010767:Phosphorylcholine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D000077337:Vorinostat; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D002087:Butyrates; D002518:Ceramides; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D010767:Phosphorylcholine; C105905:perifosine; D000077337:Vorinostat; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D048052:Mitogen-Activated Protein Kinase 3