Cytotoxicity and enhancement of the insulin signaling pathway induced by peroxidovanadium(V) complexes

Vanadium Compounds as Enzyme Inhibitors with a Focus on Anticancer Effects

Vanadium salts and coordination compounds have desirable cellular anticancer effects, and although they have been investigated in detail as a potential treatment for diabetes, less attention has been given to the anticancer effects. The inhibition of some signal transduction enzymes is known, and studies of the metabolism and activation pathways both in vitro and in vivo are important for future investigations and development of vanadium's role as a new potential drug. In addition, a new approach has demonstrated that the enhancement of oncolytic viruses using vanadium salts and coordination complexes for immunotherapy is very promising. Some differences exist between this approach and current antidiabetic and anticancer studies because vanadium(iv) complexes have been found to be most potent in the latter approach, but the few compounds investigated with oncolytic viruses show that vanadium(v) systems are more effective. We conclude that recent studies demonstrate effects on signal transduction enzymes and anticancer pathways, thus suggesting potential applications of vanadium as anticancer agents in the future both as standalone treatments as well as combination therapies.

Vanadium in Biological Action: Chemical, Pharmacological Aspects, and Metabolic Implications in Diabetes Mellitus

Vanadium compounds have been primarily investigated as potential therapeutic agents for the treatment of various major health issues, including cancer, atherosclerosis, and diabetes. The translation of vanadium-based compounds into clinical trials and ultimately into disease treatments remains hampered by the absence of a basic pharmacological and metabolic comprehension of such compounds. In this review, we examine the development of vanadium-containing compounds in biological systems regarding the role of the physiological environment, dosage, intracellular interactions, metabolic transformations, modulation of signaling pathways, toxicology, and transport and tissue distribution as well as therapeutic implications. From our point of view, the toxicological and pharmacological aspects in animal models and humans are not understood completely, and thus, we introduced them in a physiological environment and dosage context. Different transport proteins in blood plasma and mechanistic transport determinants are discussed. Furthermore, an overview of different vanadium species and the role of physiological factors (i.e., pH, redox conditions, concentration, and so on) are considered. Mechanistic specifications about different signaling pathways are discussed, particularly the phosphatases and kinases that are modulated dynamically by vanadium compounds because until now, the focus only has been on protein tyrosine phosphatase 1B as a vanadium target. Particular emphasis is laid on the therapeutic ability of vanadium-based compounds and their role for the treatment of diabetes mellitus, specifically on that of vanadate- and polioxovanadate-containing compounds. We aim at shedding light on the prevailing gaps between primary scientific data and information from animal models and human studies.

Perspectives for vanadium in health issues

Vanadium is omnipresent in trace amounts in the environment, in food and also in the human body, where it might serve as a regulator for phosphate-dependent proteins. Potential vanadium-based formulations--inorganic and coordination compounds with organic ligands--commonly underlie speciation in the body, that is, they are converted to vanadate(V), oxidovanadium(IV) and to complexes with the body's own ligand systems. Vanadium compounds have been shown to be potentially effective against diabetes Type 2, malign tumors including cancer, endemic tropical diseases (such as trypanosomiasis, leishmaniasis and amoebiasis), bacterial infections (tuberculosis and pneumonia) and HIV infections. Furthermore, vanadium drugs can be operative in cardio- and neuro-protection. So far, vanadium compounds have not yet been approved as pharmaceuticals for clinical use.

Physiological roles of peroxido-vanadium complexes: Leitmotif as their signal transduction pathway

Evidence exists that supports the various physiological roles of vanadium compounds, although the amount of vanadium in our body is limited. This limited concentration in our body does not attract much attention of the biological chemists, although the fact is present; even in the 19th century, vanadium derivatives were used for the therapeutic reagents. In the middle of the 20th century, the main focus of vanadium chemistry is mainly on the chemical and material fields. After the first discovery of vanadium compounds expressing ATPase activity, oxidovanadium(IV) sulfate was reported to have insulin mimic activity. Additionally, because some vanadium compounds possess cellular toxicity, trials were also carried out to examine the possible use of vanadium compounds as cancer therapeutics. The application of vanadium complexes was extended in recent years especially in the 21st century. In this review, we briefly explain the historical background of vanadium chemistry and also summarize the physiological role of vanadium complexes mainly focusing on the synthesis and physiological role of peroxidovanadium compounds and their interactions with insulin signal transduction pathways.