Toxic Effects of Penetrating Cations

Abstract

As mitochondria are negatively charged organelles, penetrating cations are used as a part of the chimeric molecules to deliver the specific compounds into mitochondria. However, unmodified penetrating cations affect different aspects of cellular physiology as well. In this review we have attempted to summarize the data about side effects of the commonly used natural (e.gberberine) and artificial (e.g. tetraphenylphosphonium, rhodamine, methylene blue) penetrating cations on cellular physiology. For instance, it was shown that such types of molecules can (1) facilitate proton transport across membranes; (2) react with redox groups of respiratory chain; (3) induce DNA damage; (4) interfere with pleiotropic drug resistance; (5) disturb membrane integrity (6) inhibit the enzymes. Also, the products of the biodegradation of penetrating cations can be toxic. As penetrating cations accumulate in mitochondria, their toxicity is mostly due to the mitochondrial damage. Mitochondria of certain types of cancer cells appear to be especially sensitive to penetrating cations. Here we discuss the molecular mechanisms of the toxic effects and the anti-cancer activity of the penetrating cations.