The application of metals in biological systems has been a rapidly growing branch of science. Vanadium has been investigated and reported as an anticancer agent. Melanoma is the most aggressive type of skin cancer, the incidence of which has been increasing annually worldwide. It is of paramount importance to identify novel pharmacological agents for melanoma treatment. Herein, a systematic review of publications including “Melanoma and Vanadium” was performed. Nine vanadium articles in several melanoma cells lines such as human A375, human CN-mel and murine B16F10, as well as in vivo studies, are described. Vanadium-based compounds with anticancer activity against melanoma include: (1) oxidovanadium(IV); (2) XMenes; (3) vanadium pentoxide, (4) oxidovanadium(IV) pyridinonate compounds; (5) vanadate; (6) polysaccharides vanadium(IV/V) complexes; (7) mixed-metal binuclear ruthenium(II)–vanadium(IV) complexes; (8) pyridoxal-based oxidovanadium(IV) complexes and (9) functionalized nanoparticles of yttrium vanadate doped with europium. Vanadium compounds and/or vanadium materials show potential anticancer activities that may be used as a useful approach to treat melanoma.

Background Polyoxometalates are a diverse family of metal-oxo anions of early transitional metal ions in high oxidation states, including vanadium. Such compounds are gaining increasing interest in biomedicine due to their anti-cancer activity. Regarding melanoma, available therapies’ effectiveness is still currently limited, commonly leading to relapse. For this reason, it is vital to identify novel anti-cancer agents. Methods To better understand the mechanism of action involved in the anti-cancer vanadium-based compounds in melanoma, we conducted a systematic review. Search was performed in Clinical Trials, Cochrane Library, Pubmed, Scielo, and Web of Science (20/4-8/5/2020). Review articles were excluded. Inclusion criteria considered articles between 2000 and 2020, written in English, in which vanadium compounds were evaluated alone (not combined with other drugs), allowing to recognise the effects exclusively derived from vanadium. Results Based on the inclusion/exclusion criteria, a total of 5 articles, published between 2013 and 2020, were analyzed. All tested compounds, including Oxidovanadium(IV) complexes [VIVO(mpp)2] and [VIVO(ppp)2] (VS3, VS4), reduced cellular viability. Moreover, Vanadium pentoxide (V2O5) and Xyloglucan from Copaifera Langsdorffii complexed with Oxovanadium(IV/V) (XGC:VO), in murine B16F10 cells, and Inorganic anion vanadate (VN), [VIVO (dhp)2] (VS2), and N,N’-ethylenebis (pyridoxylideneiminato) vanadium(IV) complex [Pyr2enV(IV)], in A375 cells, induced apoptosis. VN, VS2 and Pyr2enV(IV) increased reactive oxygen species (ROS) levels in A375 cells. In vivo experiments demonstrated that V2O5 prolonged the life of mice implanted with B16F10 cells, with no systemic toxicity. Conclusions Several different vanadium-based compounds have anti-cancer potential in melanoma, mainly increasing apoptosis and ROS production. Specific metal-based complexes are potential melanoma treatments, which might have been previously neglected.