title: DNA binding, DNA cleavage, and cytotoxicity studies of two new copper (II) complexes.
abstract: The DNA binding behavior of [Cu(phen)(phen-dione)Cl]Cl (1) and [Cu(bpy)(phen-dione)Cl]Cl (2) was studied with a series of techniques including UV-vis absorption, circular dichroism spectroscopy, and viscometric methods. Cytotoxicity effect and DNA unwinding properties were also investigated. The results indicate that the Cu(II) complexes interact with calf-thymus DNA by both partially intercalative and hydrogen binding. These findings have been further substantiated by the determination of intrinsic binding constants spectrophotometrically, 12.5 × 10(5) and 5 × 10(5) for 1 and 2, respectively. Our findings suggest that the type of ligands and structure of complexes have marked effect on the binding affinity of complexes involving CT-DNA. Circular dichroism results show that complex 1 causes considerable increase in base stacking of DNA, whereas 2 decreases the base stacking, which is related to more extended aromatic area of 1,10-phenanthroline in 1 rather than bipyridine in 2. Slow decrease in DNA viscosity indicates partially intercalative binding in addition to hydrogen binding on the surface of DNA. The second binding mode was also confirmed by additional tests: interaction in denaturation condition and acidic pH. Also, these new complexes induced cleavage in pUC18 plasmid DNA as indicated in gel electrophoresis and showed excellent antitumor activity against K562 (human chronic myeloid leukemia) cells.
authors.affiliation: Department of Chemistry, Sensor and Biosensor Research Center, Faculty of Science, Razi University, Kermanshah, Iran. kashanian_s@yahoo.com
authors.forename: Soheila
authors.initials: S
authors.lastname: Kashanian
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Khodaei
authors.forename: Hamideh
authors.initials: H
authors.lastname: Roshanfekr
authors.forename: Nahid
authors.initials: N
authors.lastname: Shahabadi
authors.forename: Alireza
authors.initials: A
authors.lastname: Rezvani
authors.forename: Ghobad
authors.initials: G
authors.lastname: Mansouri
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D003300:Copper / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism*; D053837:DNA Cleavage / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D020014:K562 Cells; D015394:Molecular Structure; D009691:Nucleic Acid Denaturation; D013053:Spectrophotometry; D014783:Viscosity
chemical_list: D000970:Antineoplastic Agents; D056831:Coordination Complexes; D003300:Copper; D004247:DNA; C427203:calf thymus DNA