Biochemical and proteomic analysis of a potential anticancer agent: Palladium(II) Saccharinate complex of terpyridine acting through double strand break formation.

Metal based chemotherapeutic drugs are widely used as an effective method to defeat various cancers. In this study, the mechanism of action of a novel therapeutic agent, [Pd(sac)(terpy)](sac)·4H2O (sac = saccharinate, and terpy = 2,2′:6′,2″-terpyridine) was studied. To better understand the proteomic changes in response to this agent, we performed nano LC-MS/MS analyses in human breast cancer cells (MDA-MB-231). Thirty proteins were identified to be differentially expressed more than 40% after drug treatment. Many cellular pathways were affected, including proteins involved in DNA repair, apoptosis, energy metabolism, protein folding, cytoskeleton, pre-mRNA maturation, or protein translation. The changes in protein expression were further verified for XRCC5, which plays a role in double strand break (DSB) repair, and ubiquitin, which is involved in protein degradation and apoptosis. The elevated XRCC5 levels were suggestive of increased DSBs. The presence of DSBs was confirmed by smearing of plasmid DNA i...