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

B Jhas, S Sriskanthadevan, M Skrtic, MA Sukhai… - PLoS …, 2013 - journals.plos.org
B Jhas, S Sriskanthadevan, M Skrtic, MA Sukhai, V Voisin, Y Jitkova, M Gronda, R Hurren…
PLoS One, 2013journals.plos.org
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 …
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.
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