In Vitro Studies Demonstrate Antitumor Activity of Vanadium Ions from a CaO-P 2 O 5 -CaF 2 :V 2 O 5 Glass System in Human Cancer Cell Lines A375, A2780, and Caco-2.

In this research, we investigated the structural and biological properties of phosphate glasses (PGs) after the addition of V 2 O 5 . A xV 2 O 5 ∙(100 - x)[CaF 2 ∙3P 2 O 5 ∙CaO] glass system with 0 ≤ x ≤ 16 mol% was synthesized via a conventional melt-quenching technique. Several analysis techniques (dissolution tests, pH, SEM-EDS, FT-IR, and EPR) were used to obtain new experimental data regarding the structural behavior of the system. In vitro tests were conducted to assess the antitumor character of V 2 O 5 -doped glass (x = 16 mol%) compared to the matrix (x = 0 mol%) and control (CTRL-) using several tumoral cell lines (A375, A2780, and Caco-2). The characterization of PGs showed an overall dissolution rate of over 90% for all vitreous samples (M and V1-V7) and the high reactivity of this system. EPR revealed a well-resolved hyperfine structure (hfs) typical of vanadyl ions in a C 4v symmetry. FT-IR spectra showed the presence of all structural units expected for P 2 O 5 , as well as very clear depolymerization of the vitreous network induced by V 2 O 5 . The MTT assay indicated that the viability of tumor cells treated with V7-glass extract was reduced to 50% when the highest concentration was used (10 µg/mL) compared to the matrix treatment (which showed no cytotoxic effect at any concentration). Moreover, the matrix treatment (without V 2 O 5 ) provided an optimal environment for tumor cell attachment and proliferation. In conclusion, the two types of treatment investigated herein were proven to be very different from a statistical point of view ( p < 0.01), and the in vitro studies clearly underline the cytotoxic potential of vanadium ions from phosphate glass (V7) as an antitumor agent.