The inhibitory effects of a new cobalt-based polyoxometalate on the growth of human cancer cells

A new cobalt-based polyoxometalate, (Himi)(2)[Bi2W20O66(OH)(4)Co-2(H2O)(6)Na-4 (H2O)(14)]center dot 17H(2)O (imi = iminazole) (BWCN) has been synthesized and structurally characterized. The inhibitory activities against selected human cancer lines were also determined in this study. The cell viability and chemoresistance of BWCN on human colon carcinoma HT-29 cells were assessed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide), cell morphology changes, a comet assay and western blot analysis. The typical morphologic changes of apoptosis and DNA damage indicated that BWCN could have a distinct proliferation inhibitory effect on cancer cells. BWCN as a chemotherapeutic agent also induced apoptosis on HT-29 cells and showed a significant expression of cleaved-caspase-3. These results suggested that the active site of BWCN is the polymeric anion based on the basic tectonic block {BiW9}, and the possible mechanism is related to the interference of DNA synthesis in cancer cells.