Synthesis, cytotoxicity, apoptosis and cell cycle arrest of a ruthenium multi-substituted Keggin-type polyoxotungstate

The ruthenium multi-substituted polyoxotungstate with chemical formulae of 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 ·nH 2 O( S3 ). Compound S1 was characterized by elemental analyses, EDS, TG analyses, IR, UV/Vis and XPS. The cytotoxic potential of compound S1 was tested on C33A, DLD-1, HepG-2 cancer cells and human normal embryonic lung fibroblasts cell MRC-5. The viability of the treated cells was evaluated by MTT assay. The mode of cell death was assessed by morphological study of DNA damage and apoptosis assays. Compound S1 induced cell death in a dose-dependent manner, and the mode of cell death was essentially apoptosis though necrosis was also noticed. Cell cycle analysis by flow cytometry indicated that compound S1 caused cell cycle arrest and accumulated cells in S phase.