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

A new cobalt-based polyoxometalate, (Himi)2[Bi(2)W2(0)O(66)(OH)(4)Co2(H2O)(6)Na(4) (H2O)14] · 17H2O (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 {BiW(9)}, and the possible mechanism is related to the interference of DNA synthesis in cancer cells.

Novel antitumor agent, trilacunary Keggin-type tungstobismuthate, inhibits proliferation and induces apoptosis in human gastric cancer SGC-7901 cells.

A new one-dimensional chain-like compound of tungstobismuthate, [(W(OH)2)2 (Mn(H2O)3)2(Na3(H2O)14)(BiW9O33)2](Himi)2·16H2O (1) (imi = iminazole), has been synthesized in aqueous solution. The structure of 1 was identified by elemental analysis, IR, thermogravimetry (TG), X-ray photoelectron spectroscopy (XPS), (183)W-NMR, and single crystal X-ray diffraction. To investigate the inhibitory effect of 1 on human gastric adenocarcinoma SGC-7901 cells, cell proliferation and apoptosis initiation were examined by MTT assay (MTT = 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide), flow cytometry, nuclear staining, transmission electron microscopy, single cell gel electrophoresis, DNA fragmentation, and Western blotting. The results showed that 1 inhibited cell proliferation and induced apoptosis in SGC-7901 cells in dose-dependent manner. In addition, 1 also decreased the expression of bcl-2 protein and nuclear factor-κB p65 protein in SGC-7901 cells. And expression of bcl-2 protein exhibits a decreasing trend with increase of concentration of 1. Thus, 1 possessed a potential antitumor activity in SGC-7901 cells. This suggests that polyoxotungstates will provide a promising and novel antitumor agent in prevention and treatment of gastric adenocarcinoma.

A new molybdenum(V) nickel phosphate based on divacant [H30(Mo(V)16O32)Ni14(PO4)26O2(OH)4(H2O)8]12- wheel.

A new molybdenum nickel phosphate, [H(2)en](3)Na(4)[Ni(H(2)O)(3)][H(30)(Mo(V)(16)O(32))Ni(14)(PO(4))(26)O(2) (OH)(4)(H(2)O)(8)] x 8 H(2)O 1, has been hydrothermally synthesized and structurally characterized. Compound 1 crystallizes in the monoclinic space group P2(1)/c with a = 18.6118(6) A, b = 20.9879(6) A, c = 22.9360(5) A, beta = 116.678(2) degrees, V = 8005.5(4) A(3) and Z = 2. The polyoxoanion of 1 exhibits an unusual divacant wheel-type cluster in which two {NiO(6)} octahedra are lost from the well-known "saturated" {Mo(16)TM(16)P(26)} wheel. The two vacant sites are occupied by two protonated ethylenediamines (H(2)en) via the strong hydrogen-bonding interactions between the surface O atoms of the polyoxoanions and the amine group derived from the H(2)en ligands. DC susceptibility measurements show that compound 1 exhibits strong antiferromagnetic interactions inside the wheel-type cluster.