ABSTRACT
Two new complexes of Ru(II) with mixed ligands were prepared: [Ru(bpy)2smp](PF6) (1) and [Ru(phen)2smp](PF6) (2), in which smp = sulfamethoxypyridazine; bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline. The complexes have been characterized by elemental and conductivity analyses; infrared, NMR, and electrospray ionization mass spectroscopies; and X-ray diffraction of single crystal. Structural analyses reveal a distorted octahedral geometry around Ru(II) that is bound to two bpy (in 1) or two phen (in 2) via their two heterocyclic nitrogens and to two nitrogen atoms from sulfamethoxypyridazine-one of the methoxypyridazine ring and the sulfonamidic nitrogen, which is deprotonated. Both complexes inhibit the growth of chronic myelogenous leukemia cells. The interaction of the complexes with bovine serum albumin and DNA is described. DNA footprinting using an oligonucleotide as substrate showed the complexes' preference for thymine base rich sites. It is worth notifying that the complexes interact with the Src homology SH3 domain of the Abl tyrosine kinase protein. Abl protein is involved in signal transduction and implicated in the development of chronic myelogenous leukemia. Nuclear magnetic resonance (NMR) studies of the interaction of complex 2 with the Abl-SH3 domain showed that the most affected residues were T79, G97, W99, and Y115.
Subject(s)
Antineoplastic Agents/chemical synthesis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Organometallic Compounds/chemical synthesis , Ruthenium/chemistry , Sulfamethoxypyridazine/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Circular Dichroism , Humans , K562 Cells , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Molecular Structure , Organometallic Compounds/chemistry , Organometallic Compounds/pharmacology , Proto-Oncogene Proteins c-abl/chemistry , Proto-Oncogene Proteins c-abl/metabolism , Spectrometry, Mass, Electrospray Ionization , X-Ray Diffraction , src Homology DomainsABSTRACT
A new class of polyoxoniobate complex has been synthesized and characterized as a novel anticancer agent for photodynamic therapy. The complex inhibits the growth of chronic myelogenous leukemia cells with an IC50 value of 30 µM, in the dark. However, upon exposure to light (365 nm) there is a fivefold increase in the cytotoxic activity. Light radiation activate the complex with the formation of radical species capable of interacting with DNA according to our experimental and theoretical data.