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

The complex [Pt-2(Spy(-))(4)Cl-2], where Spy(-) is deprotonated 2-mercaptop yridine, was prepared and analyzed spectroscopically. A single signal in th e Pt-195 NMR spectrum indicates the equivalence of the two Pt(III) ions. Th e interaction of this complex with DNA was studied by circular dichroism an d the modifications caused by the complex in plasmid pBR322 DNA were imaged by atomic force microscopy. Preliminary results showed higher activity aga inst HeLa and U937 tumor lines for the Pt-2-mercaptopyridine complex in com parison with cisplatin. The values of LC50 were lower than those obtained f or cisplatin. Promising perspectives or this compound are expected due to i ts similarity with the analogous Pt and 2-mercaptopyrimidine antitumor comp ound. (C)1999 Elsevier Science Inc. All rights reserved.