Potential Antitumor Effect of Newly Synthesized Dinuclear1,5-Naphthyridine-Bridging Palladium(II) Complexes

Five new dinuclear palladium(II) complexes with general formula, [{Pt(L)Cl}(2)(mu-1,5-nphe)](NO3)(2)(L is ethylenediamine (en), (+/-)-1,2-propylenediamine (1,2-pn),trans-(+/-)-1,2-diaminocyclohexane (dach), 1,3-propylenediamine (1,3-pd), (+/-)-1,3-pentanediamine (1,3-pnd) and 1,5-nphe is bridging 1,5-naphthyridine ligand) were synthesised and spectroscopically characterized.In vitrocytotoxic activity of these complexes was evaluated against mouse mammary carcinoma (4T1), colon (CT26), lung cancer cells (LLC1) and melanoma (B16-F10) as well as human lung adenocarcinoma (A549), mammary carcinoma (MDA-MB-468), and colon cancer (HCT 116). The investigated complexes reduced viability of tumor cells in dose dependent manner. Dinuclear Pd(II) complexes act less cytotoxic toward tumor cells, compare to cisplatin, but also have greater selectivity toward mesenchymal stem cells. The potential mechanism of cell death of tumor cells treated with palladium(II) 1,5-naphthyridine dinuclear complexes is enhanced apoptosis, facilitated by down-regulation of anti-apoptotic Bcl-2 and up-regulation of pro-apoptotic Caspase-3.