title: Regulation of death induction and chemosensitizing action of 3-bromopyruvate in myeloid leukemia cells: energy depletion, oxidative stress, and protein kinase activity modulation.
abstract: 3-Bromopyruvate (3-BrP) is an alkylating, energy-depleting drug that is of interest in antitumor therapies, although the mechanisms underlying its cytotoxicity are ill-defined. We show here that 3-BrP causes concentration-dependent cell death of HL60 and other human myeloid leukemia cells, inducing both apoptosis and necrosis at 20-30 μM and a pure necrotic response at 60 μM. Low concentrations of 3-BrP (10-20 μM) brought about a rapid inhibition of glycolysis, which at higher concentrations was followed by the inhibition of mitochondrial respiration. The combination of these effects causes concentration-dependent ATP depletion, although this cannot explain the lethality at intermediate 3-BrP concentrations (20-30 μM). The oxidative stress caused by exposure to 3-BrP was evident as a moderate overproduction of reactive oxygen species and a concentration-dependent depletion of glutathione, which was an important determinant of 3-BrP toxicity. In addition, 3-BrP caused glutathione-dependent stimulation of p38 mitogen-activated protein kinase (MAPK), mitogen-induced extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK), and protein kinase B (Akt)/mammalian target of rapamycin/p70S6K phosphorylation or activation, as well as rapid LKB-1/AMP kinase (AMPK) activation, which was later followed by Akt-mediated inactivation. Experiments with pharmacological inhibitors revealed that p38 MAPK activation enhances 3-BrP toxicity, which is conversely restrained by ERK and Akt activity. Finally, 3-BrP was seen to cooperate with antitumor agents like arsenic trioxide and curcumin in causing cell death, a response apparently mediated by both the generation of oxidative stress induced by 3-BrP and the attenuation of Akt and ERK activation by curcumin. In summary, 3-BrP cytotoxicity is the result of several combined regulatory mechanisms that might represent important targets to improve therapeutic efficacy.
authors.affiliation: Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain (E.C., M.C.E., C.S.-M., R.B., E.B., E.R., P.A.); and Departamento de Biología de Sistemas, Unidad de Bioquímica y Biología Molecular, Facultad de Medicina y Ciencias de la Salud, Universidad de Alcalá, Alcalá de Henares, Spain (M.C.B.-A.).
authors.forename: Eva
authors.initials: E
authors.lastname: Calviño
authors.forename: María Cristina
authors.initials: MC
authors.lastname: Estañ
authors.forename: Carlos
authors.initials: C
authors.lastname: Sánchez-Martín
authors.forename: Rocío
authors.initials: R
authors.lastname: Brea
authors.forename: Elena
authors.initials: E
authors.lastname: de Blas
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Boyano-Adánez
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rial
authors.forename: Patricio
authors.initials: P
authors.lastname: Aller
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000737:chemistry / Q000378:metabolism; D000970:Antineoplastic Agents / Q000819:agonists / Q000494:pharmacology; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004357:Drug Synergism; D004734:Energy Metabolism / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects*; D006019:Glycolysis / Q000187:drug effects; D006801:Humans; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009336:Necrosis / Q000139:chemically induced; D009363:Neoplasm Proteins / Q000819:agonists / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000819:agonists / Q000378:metabolism; D011773:Pyruvates / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D018906:Antineoplastic Agents, Alkylating; D009363:Neoplasm Proteins; D011773:Pyruvates; C017092:bromopyruvate; D011494:Protein Kinases; C494918:AKT1 protein, human; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases