Ribonucleotide Reductase as One Important Target of [Tris(1,10- phenanthroline)lanthanum(III)] Trithiocyanate (KP772)
| Autor: | Ute Jungwirth, Thomas Szekeres, Walter Berger, Daniele Biglino, Michael A. Jakupec, Michael Micksche, Petra Heffeter, L. Elbling, P. Saiko, R. Dornetshuber, Ana Popović-Bijelić, Astrid Gräslund, Bernhard K. Keppler, Nina Voevodskaya |
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| Rok vydání: | 2009 |
| Předmět: |
Cancer Research
Iron Protein subunit Antineoplastic Agents Transferrin receptor Iron Chelating Agents medicine.disease_cause Article chemistry.chemical_compound In vivo Cell Line Tumor Receptors Transferrin Ribonucleotide Reductases Drug Discovery Organometallic Compounds medicine Humans Hydroxyurea Pharmacology chemistry.chemical_classification Reactive oxygen species DNA synthesis Nucleotides Drug Synergism Cytidine DNA Ribonucleotide reductase Oncology chemistry Biochemistry Female Reactive Oxygen Species Dinucleoside Phosphates Oxidative stress Phenanthrolines |
| Zdroj: | Current Cancer Drug Targets. 9:595-607 |
| ISSN: | 1568-0096 |
| DOI: | 10.2174/156800909789056962 |
| Popis: | KP772 is a new lanthanum complex containing three 1,10-phenathroline molecules. Recently, we have demonstrated that the promising in vitro and in vivo anticancer properties of KP772 are based on p53-independent G(0)G(1) arrest and apoptosis induction. A National Cancer Institute (NCI) screen revealed significant correlation of KP772 activity with that of the ribonucleotide reductase (RR) inhibitor hydroxyurea (HU). Consequently, this study aimed to investigate whether KP772 targets DNA synthesis in tumor cells by RR inhibition. Indeed, KP772 treatment led to significant reduction of cytidine incorporation paralleled by a decrease of deoxynucleoside triphosphate (dNTP) pools. This strongly indicates disruption of RR activity. Moreover, KP772 protected against oxidative stress, suggesting that this drug might interfere with RR by interaction with the tyrosyl radical in subunit R2. Additionally, several observations (e.g. increase of transferrin receptor expression and protective effect of iron preloading) indicate that KP772 interferes with cellular iron homeostasis. Accordingly, co-incubation of Fe(II) with KP772 led to generation of a coloured iron complex (Fe-KP772) in cell free systems. In electron paramagnetic resonance (EPR) measurements of mouse R2 subunits, KP772 disrupted the tyrosyl radical while Fe-KP772 had no significant effects. Moreover, coincubation of KP772 with iron-loaded R2 led to formation of Fe-KP772 suggesting chelation of RR-bound Fe(II). Summarizing, our data prove that KP772 inhibits RR by targeting the iron centre of the R2 subunit. As also Fe-KP772 as well as free lanthanum exert significant -though less pronounced- cytotoxic/static activities, additional mechanisms are likely to synergise with RR inhibition in the promising anticancer activity of KP772. |
| Databáze: | OpenAIRE |
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