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

The ruthenium multi-substituted polyoxotungstate, K 7 [SiW 9 O 37 Ru 4 (H 2 O) 3 Cl 3 ]·15H 2 O ( S1 ), was synthesized by a conventional aqueous solution containing the trilacunary Keggin-anions β-Na 9 HSiW 9 O 34 ·12H 2 O ( S2 ) and RuCl 3 · n H 2 O ( 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.