| Summary: | Recently, we demonstrated that the anti-bacterial agent tigecycline preferentially induces death in leukemia cells through the inhibition of mitochondrial protein synthesis. To better understand the mechanisms of sensitivity and resistance to mitochondrial translation inhibition, we treated TEX leukemia cells with increasing concentrations of tigecycline over 4 months, and selected a population of cells resistant to tigecycline (RTEX+TIG). Compared to their wild type counterparts, the resistant RTEX+TIG cells had an altered metabolic profile with diminished oxidative phosphorylation and a greater reliance on glycolysis. Upon removal of tigecycline from RTEX+TIG cells, the cells re-established aerobic metabolism and oxidative phosphorylation to wild type levels. At the molecular level, these cells had increased levels of HIF1a. Strikingly, tigecycline-resistant cells had decreased expression of CD34 and CD117, clonogenic growth potential and engraftment capabilities in vivo. Thus, chronic inhibition of mitochondrial translation leads to the establishment of rho-zero-like metabolic phenotype, and is associated with differentiation of leukemia cells.
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