- Alkylation potency and protein specificity of aromatic urea derivatives and bioisosteres as potential irreversible antagonists of the colchicine-binding site
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A number of N-phenyl-N′-(2-chloroethyl)ureas (CEUs) have been shown to be potent antimitotics through their covalent binding to the colchicine-binding site on intracellular β-tubulin. The present communication aimed to evaluate the role of the electrophilic 2-chloroethyl amino moiety of CEU on cell growth inhibition and the specificity of the drugs as irreversible antagonists of the colchicine-binding site. To that end, several N-phenyl-N′-(2-ethyl)urea (EU), N-phenyl-N′-(2-chloroethyl)urea (CEU), N-aryl amino-2-oxazoline (OXA), and N-phenyl-N′-(2-chloroacetyl)urea (CAU) derivatives were prepared and tested for their antiproliferative activity, their effect on the cell cycle, and their irreversible binding to β-tubulin. EU derivatives were devoid of antiproliferative activity. CEUs (2h-2i, 2k, 2l, OXA 3e, 3h, 3i, 3k, 3l, tBCEU, and ICEU), OXA (3h, 3i, 3k, 3l, tBOXA, and IOXA), and CAU (4a-4m, tBCAU, and ICAU) had GI50 between 1.7 and 10 μM on three tumor cell lines. Cytotoxic CEU and OXA arrested the cell cycle in G2/M phase, while the corresponding CAU were not phase specific. Finally, Western blot analysis clearly showed that only CEUs 2h, 2k, 2l, tBCEU, ICEU and OXA 3h, 3i, 3k, 3l, tBOXA,and IOXA were able to bind irreversibly to the colchicine-binding site. Our results suggest that increasing the potency of the electrophilic moiety of the aromatic ureas enhances their antiproliferative activity but decreases significantly their capacity to covalently bind to the colchicine-binding site.
- Fortin, Jessica S.,Lacroix, Jacques,Desjardins, Michel,Patenaude, Alexandre,Petitclerc, Eric,C.-Gaudreault, Rene
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p. 4456 - 4469
(2008/03/13)
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- Antimitotic antitumor agents: Synthesis, structure-activity relationships, and biological characterization of N-aryl-N′-(2-chloroethyl)ureas as new selective alkylating agents
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A series of N-aryl-N′-(2-chloroethyl)ureas (CEUs) and derivatives were synthesized and evaluated for antiproliferative activity against a wide panel of tumor cell lines. Systematic structure-activity relationship (SAR) studies indicated that: (i) a branched alkyl chain or a halogen at the 4-position of the phenyl ring or a fluorenyl/indanyl group, (ii) an exocyclic urea function, and (iii) a N′-2-chloroethyl moiety were required to ensure significant cytotoxicity. Biological experiments, such as immunofluorescence microscopy, confirmed that these promising compounds alter the cytoskeleton by inducing microtubule depolymerization via selective alkylation of β-tubulin. Subsequent evaluations demonstrated that potent CEUs were weak alkylators, were non-DNA-damaging agents, and did not interact with the thiol function of either glutathione or glutathione reductase. Therefore, CEUs are part of a new class of antimitotic agents. Finally, among the series of CEUs evaluated, compounds 12, 15, 16, and 27 were selected for further in vivo trials.
- Mounetou,Legault,Lacroix,C-Gaudreault
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p. 694 - 702
(2007/10/03)
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- Synthesis and cytotoxic activity of new alkyl[3-(2-chloroethyl)ureido]benzene derivatives
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Several alkyl[3-(2-chloroethyl)ureido] (CEU) benzene derivatives were prepared as potential anticancer agents. These new compounds were readily prepared in good yields by addition of anilines to 2-chloroethylisocyanate. Their cytotoxic activity was evaluated on human breast cancer (MDA-MB-231), human colon adenocarcinoma (LoVo) and mouse lymphocytic leukemia (P388D1) tumor cell lines. Several new CEUs were significantly more cytotoxic than the nitrogen mustard chlorambucil. The biological activity of these aromatic urea derivatives seems to be related to the nature and position of the alkyl substituents on the aromatic ring. Substitution by branched alkyl groups on position 4 of the aromatic ring led to cytotoxic molecules which are up to 5 times more potent than the standard chlorambucil.
- Bechard,Lacroix,Poyet,C-Gaudreault
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p. 963 - 966
(2007/10/02)
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- 1-Aryl-3-(2-chloroethyl) ureas: Synthesis and in vitro assay as potential anticancer agents
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1-Aryl-3-(2-chlorethyl) ureas and 1-aryl-3-nitrose-3-(2-chloroethyl) ureas, derived from 4-phenylbutyric acid and alkylanillines, were synthesized and their cytotoxicity was evaluated on human adenocarcinoma cells in vitro. Methyl 4-[p-[3-(2-chloroethyl)ureido]-phenyl]butyrate, 4-methyl [3-(2-chloroethyl)ureido]benzene, and 4-butyl[3-(2-chloroethyl)ureido]benzene were found to be at least as cytotoxic as 4-[p-[bis-(2-chloroethyl)amino]phenyl]butyric acid (chlorambucil), while their N-nitrose derivatives were inactive.
- Gaudreault,lacroix,Page,Joly
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p. 185 - 187
(2007/10/02)
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