Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Blood ; 125(13): 2120-30, 2015 Mar 26.
Article in English | MEDLINE | ID: mdl-25631767

ABSTRACT

Mitochondrial respiration is a crucial component of cellular metabolism that can become dysregulated in cancer. Compared with normal hematopoietic cells, acute myeloid leukemia (AML) cells and patient samples have higher mitochondrial mass, without a concomitant increase in respiratory chain complex activity. Hence these cells have a lower spare reserve capacity in the respiratory chain and are more susceptible to oxidative stress. We therefore tested the effects of increasing the electron flux through the respiratory chain as a strategy to induce oxidative stress and cell death preferentially in AML cells. Treatment with the fatty acid palmitate induced oxidative stress and cell death in AML cells, and it suppressed tumor burden in leukemic cell lines and primary patient sample xenografts in the absence of overt toxicity to normal cells and organs. These data highlight a unique metabolic vulnerability in AML, and identify a new therapeutic strategy that targets abnormal oxidative metabolism in this malignancy.


Subject(s)
Leukemia, Myeloid, Acute/metabolism , Leukemia, Myeloid, Acute/pathology , Oxidative Stress/physiology , Oxygen Consumption , Cell Death , Cell Respiration , Electron Transport , Humans , Mitochondrial Size , Oxygen Consumption/physiology , Reactive Oxygen Species/metabolism , Tumor Cells, Cultured
2.
PLoS One ; 9(5): e95281, 2014.
Article in English | MEDLINE | ID: mdl-24871339

ABSTRACT

Tigecycline is a broad-spectrum, first-in-class glycylcycline antibiotic currently used to treat complicated skin and intra-abdominal infections, as well as community-acquired pneumonia. In addition, we have demonstrated that tigecycline also has in vitro and in vivo activity against acute myeloid leukemia (AML) due to its ability to inhibit mitochondrial translation. Tigecycline is relatively unstable after reconstitution, and this instability may limit the use of the drug in ambulatory infusions for the treatment of infection and may prevent the development of optimal dosing schedules for the treatment of AML. This study sought to identify a formulation that improved the stability of the drug after reconstitution and maintained its antimicrobial and antileukemic activity. A panel of chemical additives was tested to identify excipients that enhanced the stability of tigecycline in solution at room temperature for up to one week. We identified a novel formulation containing the oxygen-reducing agents ascorbic acid (3 mg/mL) and pyruvate (60 mg/mL), in saline solution, pH 7.0, in which tigecycline (1 mg/mL) remained intact when protected from light for at least 7 days. This formulation also preserved the drug's antibacterial and antileukemic activity in vitro. Moreover, the novel formulation retained tigecycline's antileukemic activity in vivo. Thus, we identified and characterized a novel formulation for tigecycline that preserves its stability and efficacy after reconstitution.


Subject(s)
Anti-Bacterial Agents/chemistry , Leukemia, Myeloid, Acute/drug therapy , Minocycline/analogs & derivatives , Animals , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/pharmacology , Ascorbic Acid/chemistry , Cell Line, Tumor , Cell Survival/drug effects , Chromatography, High Pressure Liquid , Drug Stability , Humans , Immunoblotting , Mice , Mice, SCID , Minocycline/chemistry , Minocycline/pharmacokinetics , Minocycline/pharmacology , Minocycline/therapeutic use , Pyruvic Acid/chemistry , Tigecycline
3.
PLoS One ; 8(3): e58367, 2013.
Article in English | MEDLINE | ID: mdl-23520503

ABSTRACT

Recently, we demonstrated that the anti-bacterial agent tigecycline preferentially induces death in leukemia cells through the inhibition of mitochondrial protein synthesis. Here, we sought to understand mechanisms of resistance to tigecycline by establishing a leukemia cell line resistant to the drug. TEX leukemia cells were treated with increasing concentrations of tigecycline over 4 months and a population of cells resistant to tigecycline (RTEX+TIG) was selected. Compared to wild type cells, RTEX+TIG cells had undetectable levels of mitochondrially translated proteins Cox-1 and Cox-2, reduced oxygen consumption and increased rates of glycolysis. Moreover, RTEX+TIG cells were more sensitive to inhibitors of glycolysis and more resistant to hypoxia. By electron microscopy, RTEX+TIG cells had abnormally swollen mitochondria with irregular cristae structures. RNA sequencing demonstrated a significant over-representation of genes with binding sites for the HIF1α:HIF1ß transcription factor complex in their promoters. Upregulation of HIF1α mRNA and protein in RTEX+TIG cells was confirmed by Q-RTPCR and immunoblotting. Strikingly, upon removal of tigecycline from RTEX+TIG cells, the cells re-established aerobic metabolism. Levels of Cox-1 and Cox-2, oxygen consumption, glycolysis, mitochondrial mass and mitochondrial membrane potential returned to wild type levels, but HIF1α remained elevated. However, upon re-treatment with tigecycline for 72 hours, the glycolytic phenotype was re-established. Thus, we have generated cells with a reversible metabolic phenotype by chronic treatment with an inhibitor of mitochondrial protein synthesis. These cells will provide insight into cellular adaptations used to cope with metabolic stress.


Subject(s)
Drug Resistance, Neoplasm , Electron Transport Complex IV/biosynthesis , Leukemia, Myeloid, Acute/metabolism , Mitochondrial Proteins/biosynthesis , Neoplasm Proteins/biosynthesis , Protein Biosynthesis , Anti-Bacterial Agents/pharmacology , Cell Line, Tumor , Electron Transport Complex IV/genetics , Gene Expression Regulation, Leukemic/drug effects , Gene Expression Regulation, Leukemic/genetics , Glycolysis/drug effects , Glycolysis/genetics , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Minocycline/analogs & derivatives , Minocycline/pharmacology , Mitochondrial Proteins/genetics , Neoplasm Proteins/genetics , Oxygen Consumption/drug effects , Oxygen Consumption/genetics , Tigecycline
4.
J Clin Invest ; 123(1): 315-28, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23202731

ABSTRACT

Despite efforts to understand and treat acute myeloid leukemia (AML), there remains a need for more comprehensive therapies to prevent AML-associated relapses. To identify new therapeutic strategies for AML, we screened a library of on- and off-patent drugs and identified the antimalarial agent mefloquine as a compound that selectively kills AML cells and AML stem cells in a panel of leukemia cell lines and in mice. Using a yeast genome-wide functional screen for mefloquine sensitizers, we identified genes associated with the yeast vacuole, the homolog of the mammalian lysosome. Consistent with this, we determined that mefloquine disrupts lysosomes, directly permeabilizes the lysosome membrane, and releases cathepsins into the cytosol. Knockdown of the lysosomal membrane proteins LAMP1 and LAMP2 resulted in decreased cell viability, as did treatment of AML cells with known lysosome disrupters. Highlighting a potential therapeutic rationale for this strategy, leukemic cells had significantly larger lysosomes compared with normal cells, and leukemia-initiating cells overexpressed lysosomal biogenesis genes. These results demonstrate that lysosomal disruption preferentially targets AML cells and AML progenitor cells, providing a rationale for testing lysosomal disruption as a novel therapeutic strategy for AML.


Subject(s)
Intracellular Membranes/metabolism , Leukemia, Myeloid, Acute/drug therapy , Leukemia, Myeloid, Acute/metabolism , Lysosomes/metabolism , Neoplastic Stem Cells/metabolism , Animals , Antimalarials/pharmacokinetics , Antimalarials/pharmacology , Cell Survival/drug effects , Female , Gene Knockdown Techniques , Genome-Wide Association Study , Humans , Intracellular Membranes/pathology , K562 Cells , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Lysosomal-Associated Membrane Protein 2 , Lysosomal Membrane Proteins/genetics , Lysosomal Membrane Proteins/metabolism , Lysosomes/genetics , Lysosomes/physiology , Male , Mefloquine/pharmacokinetics , Mefloquine/pharmacology , Mice , Neoplastic Stem Cells/pathology , Permeability/drug effects , Saccharomyces cerevisiae/genetics
5.
Cancer Cell ; 20(5): 674-88, 2011 Nov 15.
Article in English | MEDLINE | ID: mdl-22094260

ABSTRACT

To identify FDA-approved agents targeting leukemic cells, we performed a chemical screen on two human leukemic cell lines and identified the antimicrobial tigecycline. A genome-wide screen in yeast identified mitochondrial translation inhibition as the mechanism of tigecycline-mediated lethality. Tigecycline selectively killed leukemia stem and progenitor cells compared to their normal counterparts and also showed antileukemic activity in mouse models of human leukemia. ShRNA-mediated knockdown of EF-Tu mitochondrial translation factor in leukemic cells reproduced the antileukemia activity of tigecycline. These effects were derivative of mitochondrial biogenesis that, together with an increased basal oxygen consumption, proved to be enhanced in AML versus normal hematopoietic cells and were also important for their difference in tigecycline sensitivity.


Subject(s)
Antineoplastic Agents/pharmacology , Genes, Mitochondrial , Leukemia/drug therapy , Minocycline/analogs & derivatives , Mitochondria/drug effects , Neoplastic Stem Cells/drug effects , Protein Biosynthesis/drug effects , Animals , Cell Line, Tumor , Humans , Mice , Minocycline/pharmacology , Mitochondrial Proteins/genetics , Peptide Elongation Factor Tu/genetics , RNA, Small Interfering , Saccharomyces cerevisiae/drug effects , Tigecycline
SELECTION OF CITATIONS
SEARCH DETAIL
...