title: 9-Norbornyl-6-chloropurine is a novel antileukemic compound interacting with cellular GSH.
abstract: OBJECTIVE
  6-Chloropurines substituted at position 9 with bicyclic skeletons represent promising chemotherapeutic agents. We explored the metabolism and membrane transport of 9-norbornyl-6-chloropurine (NCP) aiming to understand its mechanism of action.
  
  
  METHODS
  The metabolism of NCP was studied in vitro in whole cells (CCRF-CEM), cellular extracts, subcellular fractions and purified enzymes. Transport experiments were conducted in Caco-2 cell monolayers.
  
  
  RESULTS
  Three metabolites were identified, a glutathione conjugate (NCP-GS), NCP-cysteinylglycine and NCP-cysteine. Both glutathione-S-transferase inhibition and glutathione (GSH) depletion prevented metabolite formation and increased the cytotoxicity of NCP. Transepithelial transport (Caco-2) indicated good permeability, with Papp (12.6±0.3) ×10(-5) cm/s. Importantly, the drug induced glutathione depletion in treated cells and affected the activity of several GSH-dependent enzymes.
  
  
  CONCLUSIONS
  The novel nucleoside analog NCP represents a promising orally available antileukemic agent, acting through lowering of GSH levels in tumor cells.
authors.affiliation: Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.
authors.forename: Pavla
authors.initials: P
authors.lastname: Placková
authors.forename: Nela
authors.initials: N
authors.lastname: Rozumová
authors.forename: Hubert
authors.initials: H
authors.lastname: Hrebabecky
authors.forename: Michal
authors.initials: M
authors.lastname: Sála
authors.forename: Radim
authors.initials: R
authors.lastname: Nencka
authors.forename: Tomás
authors.initials: T
authors.lastname: Elbert
authors.forename: Alexandra
authors.initials: A
authors.lastname: Dvoráková
authors.forename: Ivan
authors.initials: I
authors.lastname: Votruba
authors.forename: Helena
authors.initials: H
authors.lastname: Mertlíková-Kaiserová
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use*; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D002851:Chromatography, High Pressure Liquid; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007938:Leukemia / Q000188:drug therapy* / Q000473:pathology*; D011687:Purines / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C583750:9-norbornyl-6-chloropurine; D000970:Antineoplastic Agents; D065607:Cytochrome P-450 Enzyme Inhibitors; D011687:Purines; D003577:Cytochrome P-450 Enzyme System; D014969:Xanthine Oxidase; D005982:Glutathione Transferase; D005978:Glutathione; C079308:6-chloropurine
keywords: Substituted 6-chloropurines; carbocyclic nucleoside analogs; glutathione depletion; glutathione-S-transferase