DNA interaction and antitumor activity of a Pt(III) derivative of 2-mercaptopyridine

The complex [Pt2(Spy-)4Cl2], where Spy- is deprotonated 2-mercaptopyridine, was prepared and analyzed spectroscopically. A single signal in the 195Pt NMR spectrum indicates the equivalence of the two Pt(III) ions. The interaction of this complex with DNA was studied by circular dichroism and the modifications caused by the complex in plasmid pBR322 DNA were imaged by atomic force microscopy. Preliminary results showed higher activity against HeLa and U937 tumor lines for the Pt-2-mercaptopyridine complex in comparison with cisplatin. The values of LC50 were lower than those obtained for cisplatin. Promising perspectives for this compound are expected due to its similarity with the analogous Pt and 2-mercaptopyrimidine antitumor compound.