Inducible gene expression is an important tool in molecular biology research to study
protein function. Most frequently, the
antibiotic doxycycline is used for regulation of so-called
tetracycline (Tet)-inducible systems. In contrast to stable gene overexpression, these systems allow investigation of acute and reversible effects of cellular
protein induction. Recent reports have already called for caution when using Tet-inducible systems as the employed
antibiotics can disturb mitochondrial function and alter cellular metabolism by interfering with mitochondrial translation. Reprogramming of energy metabolism has lately been recognized as an important emerging hallmark of
cancer and is a central focus of
cancer research. Therefore, the scope of this study was to systematically analyze dose-dependent metabolic effects of
doxycycline on a panel of
glioma cell lines with concomitant monitoring of gene expression from Tet-inducible systems. We report that
doxycycline doses commonly used with inducible expression systems (0.01⁻1 µg/mL) substantially alter cellular metabolism:
Mitochondrial protein synthesis was inhibited accompanied by reduced
oxygen and increased
glucose consumption. Furthermore,
doxycycline protected human
glioma cells from
hypoxia-induced cell death. An impairment of cell growth was only detectable with higher
doxycycline doses (10 µg/mL). Our findings describe settings where
doxycycline exerts effects on eukaryotic cellular metabolism, limiting the employment of Tet-inducible systems.