title: Impact of metal coordination on cytotoxicity of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (triapine) and novel insights into terminal dimethylation.
abstract: The first metal complexes of 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (Triapine) were synthesized. Triapine was prepared by a novel three-step procedure in 64% overall yield. In addition, a series of related ligands, namely, 2-formylpyridine thiosemicarbazone, 2-acetylpyridine thiosemicarbazone, 2-pyridineformamide thiosemicarbazone, and their N(4)-dimethylated derivatives (including the N(4)-dimethylated analogue of Triapine) were prepared, along with their corresponding gallium(III) and iron(III) complexes with the general formula [M(L)(2)](+), where HL is the respective thiosemicarbazone. The compounds were characterized by elemental analysis, (1)H and (13)C NMR, IR and UV-vis spectroscopies, mass spectrometry, and cyclic voltammetry. In addition, Triapine and its iron(III) and gallium(III) complexes were studied by X-ray crystallography. All ligands and complexes were tested for their in vitro antiproliferative activity in two human cancer cell lines (41M and SK-BR-3), and structure-activity relationships were established. In general, the coordination to gallium(III) increased the cytotoxicity while the iron(III) complexes show reduced cytotoxic activity compared to the metal-free thiosemicarbazones. Selected compounds were investigated for the capacity of inhibiting ribonucleotide reductase by incorporation of (3)H-cytidine into DNA.
authors.affiliation: University of Vienna, Institute of Inorganic Chemistry, Wahringer Strasse 42, A-1090 Vienna, Austria.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Kowol
authors.forename: Robert
authors.initials: R
authors.lastname: Trondl
authors.forename: Petra
authors.initials: P
authors.lastname: Heffeter
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Arion
authors.forename: Michael A
authors.initials: MA
authors.lastname: Jakupec
authors.forename: Alexander
authors.initials: A
authors.lastname: Roller
authors.forename: Mathea Sophia
authors.initials: MS
authors.lastname: Galanski
authors.forename: Walter
authors.initials: W
authors.lastname: Berger
authors.forename: Bernhard K
authors.initials: BK
authors.lastname: Keppler
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D018360:Crystallography, X-Ray; D004354:Drug Screening Assays, Antitumor; D004563:Electrochemistry; D005708:Gallium; D006801:Humans; D007501:Iron; D010084:Oxidation-Reduction; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D012264:Ribonucleotide Reductases / Q000037:antagonists & inhibitors; D013329:Structure-Activity Relationship; D013882:Thiosemicarbazones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D002614:Chelating Agents; D056831:Coordination Complexes; D011725:Pyridines; D013882:Thiosemicarbazones; C078157:3-aminopyridine-2-carboxaldehyde thiosemicarbazone; D005708:Gallium; D007501:Iron; D012264:Ribonucleotide Reductases