- Kanamycin, a member of the aminoglycoside antibiotic family, is known primarily for its use in bacterial systems to select for plasmids carrying kanamycin resistance genes. Its mechanism of action involves binding to the 30S subunit of bacterial ribosomes, thereby inhibiting accurate translation and leading to the synthesis of nonfunctional or toxic proteins. However, when kanamycin is applied in mammalian cell culture, concerns arise due to its potential off-target effects on mitochondria, which retain prokaryote-like ribosomes.
- Mitochondria possess their own genome and ribosomes that closely resemble bacterial 70S ribosomes. This similarity makes them vulnerable to aminoglycosides like kanamycin, which may bind to mitochondrial ribosomes and inhibit mitochondrial protein synthesis. This inhibition can lead to impaired formation of respiratory chain complexes, reduced ATP production, elevated oxidative stress, and ultimately compromised mitochondrial function. In sensitive or energy-demanding mammalian cells, such effects may manifest as reduced proliferation, altered metabolism, or even induction of apoptosis.
- In cell culture settings, kanamycin is not commonly used as a standard antibiotic, largely due to these cytotoxic and mitochondrial effects. When used, typical concentrations range from 50 to 200 µg/mL, but even within this range, certain cell types may show signs of mitochondrial stress, including fragmentation, membrane potential loss, or decreased oxidative phosphorylation efficiency. The risk of mitochondrial damage increases with prolonged exposure, higher doses, or in metabolically active primary cells or stem cells.
- Therefore, while kanamycin may be useful for short-term applications—particularly in selection experiments involving transfected constructs—it is generally unsuitable for long-term mammalian cell culture when mitochondrial integrity is a priority. For studies involving mitochondrial function, metabolism, or oxidative stress, kanamycin should be avoided or used with caution, and alternative antibiotics with a safer mitochondrial profile, such as gentamicin, should be considered.
