Synthesis, characterisation, activities, cell uptake and DNA binding of [[trans-PtCl(NH3)2] [mu-(H2N(CH2)6NH2)] [trans-PdCl(NH3)2](NO3)Cl.

The dinuclear complex: [[trans-PtCl(NH(3))(2)] [mu-(H(2)N(CH(2))(6)NH(2))] trans-PdCl(NH(3))(2)Cl (code named DHD) has been synthesized and characterized. The activity against human cancer cell lines including ovarian: A2780, A2780(cisR), cell up take, level of binding with DNA and nature of interaction of the compound with pBR322 plasmid and salmon sperm DNAs have been determined. The compound is found to exhibit significant anticancer activity against ovarian cancer cell lines: A2780, A2780(cisR) and A2780(ZD0473R)--about two times as active as cisplatin against A2780 cell line, about five times as active as cisplatin against A2780(cisR) and A2780(ZD0473R) cell lines. The higher activity of DHD suggests that the compound is able to overcome multiple mechanisms of resistance operating in A2780(cisR) and A2780(ZD0473R) cell lines. DHD is believed to form a range of interstrand GG adducts with duplex DNA that induces global changes in the DNA conformation, unlike cisplatin and ZD0473 that form mainly intrastrand adducts that induces a local kink in a DNA strand. Increasing prevention of BamH1 digestion of form I and form II pBR322 plasmid DNA with the increase in concentration of DHD provides support to the idea that the interstrand binding of DHD with pBR322 plasmid DNA brings about global changes in DNA conformation.