title: Synthesis, X-ray structure, and anti-leukemic activity of oxovanadium(IV) complexes.
abstract: In a systematic effort to identify and develop effective anticancer agents, four oxovanadium(IV) complexes with 1,10-phenanthroline (Phen) or 4,7-dimethyl-1,10-phenanthroline (Me2-Phen) as ligand(s) were synthesized and characterized. Among the four oxovanadium(IV) complexes synthesized, the crystal structure of the bis(phenanthroline)oxovanadium(IV) complex bis(1,10-phenanthroline)sulfatooxovanadium(IV) ([VO(SO4)(Phen)2], compound 1) has been determined. Compound 1 crystallized in the space group P2(1)/n with unit cell parameters a = 14.2125(17) A, b = 10.8628(13) A, c = 20.143(2) A, alpha = 90 degrees, beta = 102.569(2) degrees, gamma = 90 degrees, V = 3035.3(6) A3, and Z = 4. The refinement of compound 1 by full-matrix least-squares techniques gave an R factor of 0.0785 for 4356 independent reflections. The structure contains two enantiomorphous molecules, lambda and delta, which are related by an inversion center. Compound 1 exhibited 3.5-fold more potent cytotoxic activity against NALM-6 human leukemia cells than the mono(phenanthroline)oxovanadium(IV) complex (diaqua)(1,10-phenanthroline)sulfatooxovanadium(IV) ([VO(SO4)(Phen)(H2O)2], compound 2) (IC50 values: 0.97+/-0.10 microM versus 3.40+/-0.20 microM: P=0.0004). Methyl substitution in the phenanthroline ligand enhanced the anti-leukemic activity of the mono(phenanthroline)oxovanadium(IV) complex 4.4-fold (IC50 values: 0.78+/-0.10 microM, compound 4, versus 3.40+/-0.20 microM, compound 2; P=0.0003) and the anti-leukemic activity of the bis(phenanthroline)oxovanadium(IV) complex 5.7-fold (IC50 values: 0.17+/-0.02 microM, compound 3, versus 0.97+/-0.10 microM, compound 1; P=0.001). The leading oxovanadium compound, bis(4,7-dimethyl-1,10-phenanthroline)sulfatooxovanadium(IV) ([VO(SO4)(Me2-Phen)2], compound 3) triggered the production of reactive oxygen species (ROS) in human leukemia cells, caused G1-arrest and inhibited clonogenic growth at nanomolar concentrations.
authors.affiliation: Department of Chemistry, Parker Hughes Cancer Center, Parker Hughes Institute, St. Paul, MN 55113, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Dong
authors.forename: R K
authors.initials: RK
authors.lastname: Narla
authors.forename: E
authors.initials: E
authors.lastname: Sudbeck
authors.forename: F M
authors.initials: FM
authors.lastname: Uckun
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D008024:Ligands; D008747:Methylcellulose / Q000378:metabolism; D008956:Models, Chemical; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D017382:Reactive Oxygen Species; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014638:Vanadates / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D008024:Ligands; D017382:Reactive Oxygen Species; C075743:oxovanadium IV; D014638:Vanadates; D008747:Methylcellulose