title: Chloroethyl urea derivatives block tumour growth and thioredoxin-1 nuclear translocation.
abstract: Aryl chloroethyl ureas (CEUs) are new protein alkylating agents exhibiting anticancer activity both in vitro and in vivo. We report herein that 14C-labeled CEU derivatives, designated CEU-025 and CEU-027, covalently bind to thioredoxin-1 (TRX1). Covalent binding of these molecules slightly decreases the disulfide-reducing activity of recombinant TRX1, when compared with the effect of strong thioalkylating agents such as N-ethylmaleimide. Moreover, site-directed mutagenesis and diamide competition assays demonstrated that TRX1 cysteinyl residues are not the prime targets of CEUs. CEU-025 abrogates the nuclear translocation of TRX1 in human cancer cells. In addition, we show that CEU-025 can block TRX1 nuclear translocation induced by cisplatin. Unexpectedly, pretreatment with sublethal CEU-025 concentrations that block TRX1 nuclear translocation protected the cells against cisplatin cytotoxicity. Overexpression of TRX1 in HT1080 fibrosarcoma cells attenuated CEU-025 cytotoxicity, while its suppression using TRX1-specific siRNA increased the effects of CEU-025, suggesting that loss of function of TRX1 is involved, at least in part, in the cytotoxic activity of CEU-025. These results suggest that CEU-025 and CEU-027 exhibit anticancer activity through a novel, unique mechanism of action. The importance of TRX1 and the dependence of the cytotoxicity of CEU-025 and CEU-027 on TRX1 intracellular localization are also discussed.
authors.affiliation: Unité de Biotechnologie et de Bioingénierie, CHUQ, Hôpital Saint-François d'Assise, Université Laval, Québec, QC, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Patenaude
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Fortin
authors.forename: Réna
authors.initials: R
authors.lastname: Deschenes
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Côté
authors.forename: Jacques
authors.initials: J
authors.lastname: Lacroix
authors.forename: René
authors.initials: R
authors.lastname: C-Gaudreault
authors.forename: Eric
authors.initials: E
authors.lastname: Petitclerc
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D002384:Catalysis; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects*; D002945:Cisplatin / Q000494:pharmacology; D006801:Humans; D021381:Protein Transport / Q000187:drug effects; D013329:Structure-Activity Relationship; D013879:Thioredoxins / Q000378:metabolism*; D014508:Urea / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D013879:Thioredoxins; D014508:Urea; D002945:Cisplatin