Metabolic adaptation to chronic inhibition of mitochondrial protein synthesis in acute myeloid leukemia cells

PLoS One. 2013;8(3):e58367. doi: 10.1371/journal.pone.0058367. Epub 2013 Mar 8.

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:HIF1β 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Cell Line, Tumor
  • Drug Resistance, Neoplasm*
  • Electron Transport Complex IV / biosynthesis*
  • 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 / metabolism*
  • Leukemia, Myeloid, Acute / pathology
  • Minocycline / analogs & derivatives
  • Minocycline / pharmacology
  • Mitochondrial Proteins / biosynthesis*
  • Mitochondrial Proteins / genetics
  • Neoplasm Proteins / biosynthesis*
  • Neoplasm Proteins / genetics
  • Oxygen Consumption / drug effects
  • Oxygen Consumption / genetics
  • Protein Biosynthesis*
  • Tigecycline

Substances

  • Anti-Bacterial Agents
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Mitochondrial Proteins
  • Neoplasm Proteins
  • Tigecycline
  • Electron Transport Complex IV
  • Minocycline