In vitro and in vivoactivity of series of cationic dinuclearPt(II) complexes.

The antitumour potential of nine dinuclear platinum(II) complexes of the type [{Pt(L)Cl}2(μ-X)]2+(where L represents two NH3 or different bidentantly coordinated diamine ligand - ethylenediamine, en; (±)-1,2-propylenediamine, 1,2-pn; isobutylenediamine, ibn; trans-(±)-1,2-diaminocyclohexane, dach; 1,3-propylenediamine, 1,3-pd; 2,2-dimethyl-1,3-propylenediamine, 2,2-diMe-1,3-pd; (±)-1,3-pentanediamine,1,3-pnd, and X is a bridging pyrazine (pz) or pyridazine (pydz) ligand) were determined by in vitro and in vivo assays using the CT26 cell line and a murine model of heterotopic colon cancer tumour induced in immunocompetent BALB/c mice. This study concludes that complexes Pt1, Pt2 and Pt7 possess significant in vitro cytotoxic activity against mouse colon carcinoma CT26 cells, while all these complexes show moderate apoptotic effect. Complexes Pt1 and Pt7 arrested CT26 cells in G2/M phase of cell cycle, while, evaluated by detection of Ki67 expressing cells, complexes Pt5 and Pt6 exerted the highest antiproliferative effect. Complexes Pt1 and Pt2 exerted significant in vivo antitumour effects. These complexes reduced the growth of primary tumour and the incidence of lung and liver metastases without causing the significant hepato- and nephro- toxicity. Our data indicate considerable antitumour activity of platinum(II) complexes against CT26 cells in vitro and in vivo and imply possible further investigations on their role as potential chemotherapeutic agents.