Michel Desjardins

University Laval, Québec, Quebec, Canada

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Publications (4)11.59 Total impact

  • Article: Selective alkylation of beta(II)-tubulin and thioredoxin-1 by structurally related subsets of aryl chloroethylureas leading to either anti-microtubules or redox modulating agents.
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    ABSTRACT: Aryl chloroethylureas (CEUs) are potent anti-neoplastic agents alkylating specific intracellular proteins such as beta(II)-tubulin. Recently we have identified a new subset of CEU derived from compound 36 that alkylates thioredoxin isoform 1 (Trx-1), inhibits the nuclear translocation of Trx-1, and favors the accumulation of cells in G(0)/G(1) phase. We have evaluated the effects of various substituents and their position on the aromatic ring of a series of derivatives of 36 on (i) the anti-proliferative activity, (ii) the cell cycle progression, (iii) the nuclear translocation of Trx-1, and (iv) their covalent binding to beta-tubulin. The same experiments were performed on representative CEU derivatives where the 2-chloroethyl amino moiety is replaced by either an ethyl, a 2-aminooxazolinyl or a 2-chloroacetyl group. On one hand, our results suggest that CEUs substituted on the phenyl ring at position 3 or 4 by cycloalkyl and substituted cycloalkyl or cycloalkoxy groups inhibit the nuclear translocation of Trx-1 and arrest the cell cycle progression in G(0)/G(1). On the other hand, CEUs substituted by a fused aromatic ring, an aliphatic chain, or a fused aliphatic ring are alkylating beta(II)-tubulin but not Trx-1. Beside the expected inactivity of the ethylurea derivatives, none of the modification to the electrophilic moiety led to cross-selectivity of the drugs toward beta-tubulin but increased the anti-proliferative activity and resulted in mitigated effects on Trx-1 translocation.
    Bioorganic & medicinal chemistry 07/2008; 16(15):7277-90. · 2.82 Impact Factor
  • Article: Alkylation potency and protein specificity of aromatic urea derivatives and bioisosteres as potential irreversible antagonists of the colchicine-binding site.
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    ABSTRACT: 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 beta-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 beta-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 GI(50) between 1.7 and 10microM on three tumor cell lines. Cytotoxic CEU and OXA arrested the cell cycle in G(2)/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.
    Bioorganic & Medicinal Chemistry 08/2007; 15(13):4456-69. · 2.92 Impact Factor
  • Article: N-Phenyl-N'-(2-chloroethyl)ureas (CEU) as potential antineoplastic agents. Part 2: role of omega-hydroxyl group in the covalent binding to beta-tubulin.
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    ABSTRACT: Tubulin is the target of many anticancer drugs, including N-phenyl-N'-(2-chloroethyl)urea (CEU). Unlike most anti-beta-tubulin agents, CEUs are protein monoalkylating agents binding through their N'-(2-chloroethyl)urea moiety to an amino acid nearby the colchicine-binding site on beta-tubulin isoform-2. Following the previously synthesized and attractive N-(3-omega-hydroxyalkylphenyl)-N'-(2-chloroethyl)urea that exhibited growth inhibitory activity at the nanomolar level, we investigated the importance of lower alkyl and alkoxy groups to evaluate the effect of hydroxylated group and chain length on both cell growth inhibition and the mechanism of action of CEU. Here, we describe the preparation of two new series of CEU and show that the most potent CEU derivatives beside the omega-hydroxylated 1f were 2f and 3e, respectively. We have confirmed that the pentyl substituted CEUs 1f, 2f, and 3e are still covalently binding to beta-tubulin and still arrest cell division in G(2)/M phase.
    Bioorganic & Medicinal Chemistry 03/2007; 15(3):1430-8. · 2.92 Impact Factor
  • Article: Optimized N-phenyl-N'-(2-chloroethyl)ureas as potential antineoplastic agents: synthesis and growth inhibition activity.
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    ABSTRACT: In our ongoing research program aimed at the optimization of microtubule-self-assembly disrupting agents, we have prepared three series of phenylurea analogues (CEU), derived from N-(3-omega-hydroxyalkyl or 4-omega-hydroxyalkyl or 3-omega-hydroxyalkynyl)-phenyl-N'-(2-chloroethyl)ureas. Most compounds exhibit potent growth inhibitory activity on human colon carcinoma HT-29, human skin melanoma M21, and human breast carcinoma MCF-7 tumor cell lines, with a GI50 ranging from 250 nM to 8 microM. Among these new molecules, three CEUs exhibit GI50 in the nanomolar range. They are more potent by approximately an order of magnitude than previously described CEU analogues. As such, they are attractive hit compounds for the development of potent new alkylating antitubulin drugs.
    Bioorganic & Medicinal Chemistry 01/2006; 13(24):6703-12. · 2.92 Impact Factor