title: The purine analog fludarabine acts as a cytosolic 5'-nucleotidase II inhibitor.
abstract: For several years the IMP/GMP-preferring cytosolic 5'-nucleotidase II (cN-II) has been considered as a therapeutic target in oncology. Indeed, various reports have indicated associations between cN-II expression level and resistance to anticancer agents in several cancer cell lines and in patients affected with neoplasia, mainly by hematologic malignancies. In this paper we present evidence showing that, among the commonly used cytotoxic nucleoside analogs, fludarabine can act as a cN-II inhibitor. In vitro studies using the wild type recombinant cN-II demonstrated that fludarabine inhibited enzymatic activity in a mixed manner (Ki 0.5 mM and Ki' 9 mM), whereas no inhibition was observed with clofarabine and cladribine. Additional experiments with mutant recombinant proteins and an in silico molecular docking indicated that this inhibition is due to an interaction with a regulatory site of cN-II known to interact with adenylic compounds. Moreover, synergy experiments between fludarabine and 6-mercaptopurine in human follicular lymphoma (RL) and human acute promyelocytic leukemia (HL-60) cells transfected with control or cN-II-targeting shRNA-encoding plasmids, showed synergy in control cells and antagonism in cells with decreased cN-II expression. This is in line with the hypothesis that fludarabine acts as a cN-II inhibitor and supports the idea of using cN-II inhibitors in association with other drugs to increase their therapeutic effect and decrease their resistance.
authors: University of Pisa, Department of Biology, Biochemistry Unit, Pisa, Italy. Electronic address: f.cividini@gmail.com.
authors: F
authors: F
authors: Cividini
authors: University of Pisa, Department of Biology, Biochemistry Unit, Pisa, Italy.
authors: R
authors: R
authors: Pesi
authors: Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS), UMR 5236, CNRS - Université de Montpellier, 1919 route de Mende, 34293 Montpellier cedex 5, France.
authors: L
authors: L
authors: Chaloin
authors: University of Sassari, Department of Chemistry and Pharmacology, Sassari, Italy.
authors: S
authors: S
authors: Allegrini
authors: University of Pisa, Department of Biology, Biochemistry Unit, Pisa, Italy.
authors: M
authors: M
authors: Camici
authors: Université de Lyon, F-69000 Lyon, France; Université de Lyon 1, F-69622 Lyon, France; INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France; CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France.
authors: E
authors: E
authors: Cros-Perrial
authors: Université de Lyon, F-69000 Lyon, France; Université de Lyon 1, F-69622 Lyon, France; INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France; CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France.
authors: C
authors: C
authors: Dumontet
authors: Université de Lyon, F-69000 Lyon, France; Université de Lyon 1, F-69622 Lyon, France; INSERM U1052, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France; CNRS UMR 5286, Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France.
authors: L P
authors: LP
authors: Jordheim
authors: University of Pisa, Department of Biology, Biochemistry Unit, Pisa, Italy.
authors: M G
authors: MG
authors: Tozzi
mesh_terms: D015720:5'-Nucleotidase / Q000037:antagonists & inhibitors*; D003600:Cytosol / Q000201:enzymology*; D019075:Electrophoresis, Capillary; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D062105:Molecular Docking Simulation; D016297:Mutagenesis, Site-Directed; D014740:Vidarabine / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D015720:5'-Nucleotidase; D014740:Vidarabine; C024352:fludarabine
keywords: Adenosine analogs; Cancer pharmacology; Chemoresistance; Cytosolic 5′-nucleotidase II; Fludarabine