Synthesis, Cytotoxicity, Apoptosis and Cell Cycle Arrest of a Ruthenium(II)-Substituted Keggin Polyoxotungstate

\nThe ruthenium multi-substituted polyoxotungstate, K7[SiW9O37Ru4(H2O)3Cl3]·15H2O (S1), was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anions β-Na9HSiW9O34·12H2O (S2) and RuCl3·nH2O (S3). Compound S1 was characterized by elemental analysis, energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TG), infrared spectroscopy (IR), uliraviolet visible absorption spectroscopy (UV/Vis) and X-ray photoelectron spectroscopy (XPS). The cytotoxicitycy of S1 was tested in C33A (human cervical cancer), DLD-1 (human colon cancer), HepG2 (human liver cancer) and human normal embryonic lung fibroblasts cell (MRC-5). And the viability of these treated cells was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.To explore the mode of cell death induced by S1, morphological study of DNA damage and apoptosis assays were conducted. These analyses revealed that S1 exerted its cytotoxic effect in a dose-dependent manner, primarily triggering apoptotic cell death. Cell cycle analysis by flow cytometry indicated that compound S1 caused cell cycle arrest and accumulated cells in S phase. \n