title: Biochemical and proteomic analysis of a potential anticancer agent: Palladium(II) Saccharinate complex of terpyridine acting through double strand break formation.
abstract: 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 in vitro and induction of γH2AX foci in vivo. There was also increased intracellular reactive oxygen species (ROS) formation, as detected by 2',7'-dichlorofluorescein diacetate (DCFDA) staining. Scavenging ROS by N-acetylcysteine rescued cell death in response to Pd(II) treatment, potentially explaining how the Pd(II) complex damaged the DNA. The details of this analysis and the significance will be discussed during the scope of this work.
authors.affiliation: TUBITAK, Marmara Research Center, Genetic Engineering and Biotechnology Institute, Gebze/Kocaeli, 41470, Turkey.
authors.forename: Zelal
authors.initials: Z
authors.lastname: Adiguzel
authors.forename: Ahmet Tarik
authors.initials: AT
authors.lastname: Baykal
authors.forename: Omer
authors.initials: O
authors.lastname: Kacar
authors.forename: Veysel T
authors.initials: VT
authors.lastname: Yilmaz
authors.forename: Engin
authors.initials: E
authors.lastname: Ulukaya
authors.forename: Ceyda
authors.initials: C
authors.lastname: Acilan
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor / Q000187:drug effects / Q000378:metabolism; D056831:Coordination Complexes / Q000494:pharmacology*; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects*; D004265:DNA Helicases / Q000378:metabolism; D005260:Female; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D000072200:Ku Autoantigen; D010165:Palladium / Q000737:chemistry / Q000494:pharmacology*; D040901:Proteomics / Q000379:methods; D017382:Reactive Oxygen Species / Q000378:metabolism; D053719:Tandem Mass Spectrometry
chemical_list: D000970:Antineoplastic Agents; D056831:Coordination Complexes; D017382:Reactive Oxygen Species; C000601946:saccharinate(2,2'-6',2'-terpyridine)palladium(II); D010165:Palladium; D004265:DNA Helicases; C106893:XRCC5 protein, human; D000072200:Ku Autoantigen
keywords: DNA double strand breaks; anticancer drugs; apoptosis; nonhomologous end joining; palladium(II) saccharinate complex with terpyridine; proteomics; reactive oxygen species