Antitumoral effect of vanadium compounds in malignant melanoma cell lines

In this study we evaluated the anticancer activity against malignant melanoma (MM) of four different vanadium species: the inorganic anion vanadate(V) (indicated with VN), and three oxidovanadium(IV) complexes, [V^IVO(dhp)₂] where dhp^- is the anion 1,2-dimethyl-3-hydroxy-4(1H)-pyridinonate (indicated with VS2), [V^IVO(mpp)₂] where mpp^- is 1-methyl-3-hydroxy-4(1H)-pyridinonate (indicated with VS3), and [V^IVO(ppp)₂] where ppp^- is 1-phenyl-2-methyl-3-hydroxy-4(1H)-pyridinonate (indicated with VS4). The antitumor effects of these compounds were studied against two different MM cell lines (A375 and CN-mel) and a fibroblast cell line (BJ) as normal control. All tested V compounds exert antiproliferative activity on MM cells in a dose dependent manner (IC₅₀ ranges from 2.4μM up to 14μM) being A375 the most sensitive cell line. VN and VS2 were the two most active compounds against A375 (IC₅₀ of 4.7 and 2.6μM, respectively), causing apoptosis and cell cycle block. The experimental data indicate that the cell cycle arrest occurs at different phases for the two V species analyzed (G2 checkpoint for VN and G0/G1 for VS2), showing the importance of the chemical form in determining their mechanism of action. These results add more insights into the landscape of vanadium versatility in biological systems and into its role as a potential cancer therapeutic agent.