title: Ajoene-induced cell death in human promyeloleukemic cells does not require JNK but is amplified by the inhibition of ERK.
abstract: Treatment of human promyeloleukemic HL-60 cells with the experimental antileukemic drug ajoene induces the activation of the mitogen-activated protein kinases (MAPKs) c-Jun NH(2)-terminal kinase (JNK), p38 and extracellular signal-regulated kinases (ERK) 1/2 as well as the survival kinase Akt. JNK activation occurred in HL-60/neo, HL-60/bcl-x(L), and in HL-60 cells pretreated with the pan-caspase inhibitor zVAD-fmk, indicating that JNK activation is not dependent on ajoene-induced mitochondria perturbation and subsequent caspase activation. Cells overexpressing a dominant-negative JNK showed no altered sensitivity towards ajoene suggesting that the activation of JNK is not necessary for ajoene-induced cell death. Inhibition of p38 MAPK by SB 203580 had no influence on ajoene-mediated apoptosis. In contrast, inhibition of ERK1/2 vastly enhanced ajoene-induced cell death. The survival kinase Akt, in contrast, did not participate in ajoene-induced death signaling as shown by the use of the phosphatidylinositol-3-kinase inhibitor wortmannin. Thus in contrast to the previous findings regarding stress-induced cell death, ajoene-mediated activation of JNK and p38 has no impact on ajoene-induced apoptosis in HL-60 cells. Blockade of ERK1/2 but not Akt pathways leads to sensitization of cells against ajoene-mediated apoptosis supporting the view that inhibition of ERK1/2 is a valuable strategy to increase the sensitivity of promyeloleukemic cells towards ajoene.
authors.affiliation: Department of Pharmacy, Center of Drug Research, University of Munich, Germany.
authors.forename: Dorothee S M
authors.initials: DS
authors.lastname: Antlsperger
authors.forename: Verena M
authors.initials: VM
authors.lastname: Dirsch
authors.forename: Dulce
authors.initials: D
authors.lastname: Ferreira
authors.forename: Jen-Liang
authors.initials: JL
authors.lastname: Su
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Kuo
authors.forename: Angelika M
authors.initials: AM
authors.lastname: Vollmar
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D004220:Disulfides / Q000494:pharmacology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology / Q000473:pathology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology*; D013454:Sulfoxides
chemical_list: D004220:Disulfides; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D013454:Sulfoxides; C048980:ajoene; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases