title: Azinomycin epoxide induces activation of apoptosis signal-regulating kinase 1 (ASK1) and caspase 3 in a HIF-1alpha-independent manner in human leukaemia myeloid macrophages.
abstract: In recent years there has been an increasing interest in the azinomycin epoxide (2S, 3S)-benzyl 3,4-epoxy-2-(3-methoxy-5-methyl-1-naphthoyloxy)-3-methylbut anamide (EA), a potent cytotoxic and anti-tumour antibiotic. However, the molecular mechanisms of its cytotoxic activity have not yet been investigated. Here we report that exposure of the THP-1 human myeloid leukaemia cells to EA leads to the activation of apoptosis signal-regulating kinase 1 via a redox-dependent mechanism in a concentration and time-dependent manner. Accumulation of p53 and activation of caspase 3 were also seen. This was consistent with EA concentration-dependent accumulation of HIF-1alpha protein peaking after 4 h of stimulation with EA. Experiments with THP-1 cells, where the activity of ASK1 was blocked by transfection with the dominant-negative form of ASK1 demonstrated the importance of this enzyme for EA-dependent activation of caspase 3. Accumulated HIF-1alpha protein did not, however, promote EA-induced activation of caspase 3 or accumulation of p53. The experiments with p53 knockdown THP-1 cells demonstrated that this protein is not important for EA-induced activation of ASK1, caspase 3 or accumulation of HIF-1alpha protein. This is consistent with previous results indicating a reduced activity of p53 in THP-1 cells.
authors.affiliation: Medway School of Pharmacy, University of Kent, United Kingdom.
authors.forename: Maxwell A
authors.initials: MA
authors.lastname: Casely-Hayford
authors.forename: Sally A
authors.initials: SA
authors.lastname: Nicholas
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Sumbayev
mesh_terms: D000818:Animals; D053148:Caspase 3 / Q000378:metabolism*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004852:Epoxy Compounds / Q000494:pharmacology*; D055785:Gene Knockdown Techniques; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007951:Leukemia, Myeloid / Q000473:pathology*; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009281:Naphthalenes / Q000494:pharmacology*; D010084:Oxidation-Reduction; D055550:Protein Stability / Q000187:drug effects; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D004852:Epoxy Compounds; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009281:Naphthalenes; D016159:Tumor Suppressor Protein p53; C515726:azinomycin epoxide; D048848:MAP Kinase Kinase Kinase 5; D053148:Caspase 3