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Fortin, Sébastien

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Université Laval. Faculté de pharmacie



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  • PublicationAccès libre
    New testosterone derivatives as semi-synthetic anticancer agents against prostate cancer : synthesis and preliminary biological evaluation
    (Bentham Science Publishers, 2015-09-01) Morin, Nathalie; Fortin, Sébastien; Bruneau, Julie; Brasseur, Kevin; Leblanc, Valérie; Bérubé, Gervais
    Prostate cancer (PC) is a major health issue in the world. Treatments of localized PC are quite efficient and usually involve surgery, radiotherapy and/or hormonal therapy. Metastatic PC is however rarely curable to this day. Treatments of metastatic PC involve radiotherapy, chemotherapy and hormonal treatment such as orchiectomy, antiandrogens and luteinizing hormone-releasing hormone agonists. The suppression of tumor growth by hormonal treatment is efficient but overtime resistance still occurs and the disease progresses. Thus, more urgently than ever there is a need for discovery of new treatment options for castration-resistant PC (CRPC). Hence, we designed and tested a series of amide derivatives located at position 7α of testosterone as prospective “natural” or “semisynthetic” anticancer agents against CRPC with the goal of discovering therapeutic alternatives for the disease. This manuscript describes an efficient path towards the target molecules that are made in only 6 or 7 chemical steps from testosterone in good overall yields. This strategy can be used to make several compounds of interest that present higher biological activity than the classic antiandrogen; cyproterone acetate (3). The best testosterone-7α-amide was the N-2-pyridylethylamide (25) which was as active as the antiandrogen cyproterone acetate (3) on androgen-dependent LNCaP cells and 2.7 times more active on androgen-independent PC3 prostate cancer cells. The results obtained show the synthetic feasibility and the potential for future development of this unique class of semi-synthetic anticancer agents that offer the premise of new treatment modalities for patients afflicted with CRPC.
  • PublicationAccès libre
    Design, synthesis, cytocidal activity and estrogen receptor a affinity of doxorubicin conjugates at 16α-position of estrogen for site-specific treatment of estrogen receptor-positive breast cancers
    (Elsevier, 2012-07-15) Saha, Pijus; Fortin, Sébastien; Asselin, Éric; Leblanc, Valérie; Parent, Sophie; Bérubé, Gervais
    Doxorubicin (DOX) is an important medicine for the treatment of breast cancer, which is the most frequently diagnosed and the most lethal cancer in women worldwide. However, the clinical use of DOX is impeded by serious toxic effects such as cardiomyopathy and congestive heart failure. Covalently linking DOX to estrogen to selectively deliver the drug to estrogen receptor-positive (ER+) cancer tissues is one of the strategies under investigation for improving the efficacy and decreasing the cardiac toxicity of DOX. However, conjugation of drug performed until now was at 3- or 17-position of estrogen, which is not ideal since the hydroxyl groups at this position are important for receptor binding affinity. In this study, we designed, prepared and evaluated in vitro the first estrogen–doxorubicin conjugates at 16α-position of estradiol termed E-DOXs (8a–d). DOX was conjugated using a 3–9 carbon atoms alkylamide linking arm. E-DOXs were prepared from estrone using a seven-step procedure to afford the desired conjugates in low to moderate yields. The antiproliferative activities of the E-DOX 8a conjugate through a 3-carbon spacer chain on ER+ MCF7 and HT-29 are in the micromolar range while inactive on M21 and the ER− MDA-MB-231 cells (>50 μM). Compound 8a exhibits a selectivity ratio (ER+/ER− cell lines) of >3.5. Compounds 8b–8d bearing alkylamide linking arms ranging from 5 to 9 carbon atoms were inactive at the concentrations tested (>50 μM). Interestingly, compounds 8a–8c exhibited affinity for the estrogen receptor α (ERα) in the nanomolar range (72–100 nM) whereas compound 8d exhibited no affinity at concentrations up to 215 nM. These results indicate that a short alkylamide spacer is required to maintain both antiproliferative activity toward ER+ MCF7 and affinity for the ERα of the E-DOX conjugates. Compound 8a is potentially a promising conjugate to target ER+ breast cancer and might be useful also for the design of more potent E-DOX conjugates.
  • PublicationAccès libre
    Synthesis and biological evaluation of novel N-phenyl ureidobenzenesulfonate derivatives as potential anticancer agents. Part 2. Modulation of the ring B
    (Elsevier, 2015-09-10) Fortin, Sébastien; Masson, Jean-Yves; Côté, Marie-France; Gagné-Boulet, Mathieu; Lacroix, Jacques M.; Moussa, Hanane
    DNA double strand-breaks (DSBs) are the most deleterious lesions that can affect the genome of living beings and are lethal if not quickly and properly repaired. Recently, we discovered a new family of anticancer agents designated as N-phenyl ureidobenzenesulfonates (PUB-SOs) that are blocking the cells cycle progression in S-phase and inducing DNA DSBs. Previously, we have studied the effect of several modifications on the molecular scaffold of PUB-SOs on their cytocidal properties. However, the effect of the nature and the position of substituents on the aromatic ring B is still poorly studied. In this study, we report the preparation and the biological evaluation of 45 new PUB-SO derivatives substituted by alkyl, alkoxy, halogen and nitro groups at different positions on the aromatic ring B. All PUB-SOs were active in the submicromolar to low micromolar range (0.24–20 μM). The cell cycle progression analysis showed that PUB-SOs substituted at position 2 by alkyl, halogen or nitro groups or substituted at position 4 by a hydroxyl group arrest the cell cycle progression in S-phase. Interestingly, all others PUB-SOs substituted at positions 3 and 4 arrested the cell cycle in G2/M-phase. PUB-SOs arresting the cell cycle progression in S-phase also induced the phosphorylation of H2AX (γH2AX) which is indicating the generation of DNA DSBs. We evidenced that few modifications on the ring B of PUB-SOs scaffold lead to cytocidal derivatives arresting the cell cycle in S-phase and inducing γH2AX and DSBs. In addition, this study shows that these new anticancer agents are promising and could be used as alternative to circumvent some of the biopharmaceutical complications that might be encountered during the development of PUB-SOs.
  • PublicationAccès libre
    Advances in the development of hybrid anticancer drugs
    (Taylor & Francis Online, 2013-05-07) Fortin, Sébastien; Bérubé, Gervais
    Introduction: Hybrid anticancer drugs are of great therapeutic interests as they can potentially overcome most of the pharmacokinetic drawbacks encountered when using conventional anticancer drugs. In fact, the future of hybrid anticancer drugs is very bright for the discovery of highly potent and selective molecules that triggers two or more cytocidal pharmacological mechanisms of action acting in synergy to inhibit cancer tumor growth. Areas covered: This review represents the most advanced and recent data in the field of hybrid anticancer agents covering mainly the past 5 years of research. It also accounts for other significant reviews already published on the topic of anticancer hybrids. The review showcases the research that is at the leading edge of hybrid anticancer drug discovery. The main areas covered by the present review are: DNA alkylating agent hybrids (e.g., platinum(II), nitrogen mustard, etc.), vitamin-D receptor, agonist–histone deacetylase inhibitors, combi-molecule therapies and other types of hybrid anticancer agents. Expert opinion: The current development in the field describes strategies that have never been used before for the design of hybrid anticancer drugs. The information currently available and described in this section allows us to identify the main parameters required to design such molecules. It also provides a clear view of the future directions that must be explored for the successful development and discovery of useful hybrid anticancer drugs.
  • PublicationAccès libre
    Synthesis, antiproliferative activity and estrogen receptor α affinity of novel estradiol-linked platinum(II) complex analogs to carboplatin and oxaliplatin. Potential vector complexes to target estrogen-dependent tissues
    (ScienceDirect, 2011-12-17) Saha, Pijus; Fortin, Sébastien; Descôteaux, Caroline; Asselin, Éric; Brasseur, Kevin; Parent, Sophie; Leblanc, Valérie; Bérubé, Gervais
    In the course of efforts to develop 17β-estradiol-linked to anticancer agents targeting estrogen-dependent tissue, we identified three estradiol-linked platinum(II) complex analogs to cisplatin (E-CDDP) derivatives namely: VP-128 (1), CD-38 (2) and JMP-39 (3) that exhibit potent in vitro and in vivo (for derivative VP-128) activity along with interaction with the estrogen receptor α (ERα). In this study, we prepared and biologically evaluated two novel classes of estradiol-linked platinum(II) complex analogs to carboplatin (E-CarboP, 1a-3a) and oxaliplatin (E-OxaP, 1b-3b). E-CarboP and E-OxaP were designed and based on the estradiol-linker scaffold of E-CDDP derivatives previously identified. Consequently, we assessed the importance of the nature of platinum(II) salt on the antiproliferative activity on MCF-7 and MDA-MB-231 human mammary carcinoma cell lines together with affinity for the ERα by replacing the dichloroplatinum(II) moiety by a cyclobutane-1,1-dicarboxylateplatinum(II) or an oxalateplatinum(II) moiety. Except for compound 3b which is inactive at the concentration tested, the antiproliferative activity of all compounds on both human mammary carcinomas cell lines are in micromolar range and are more active than carboplatin and oxaliplatin alone but less active that their E-CDDP counterparts (1-3). In addition, E-CarboP derivatives 1a-3a show very low affinity for ERα whereas E-OxaPs 1b and 2b show higher affinity for ERα than their parents E-CDDPs (1-2), suggesting that the nature of the platinum(II) salt involved in the vector complexes is extremely important to both retain significant antiproliferative activity and selectivity for the ERα and possibility to target estrogen-dependent tissues. Finally, E-OxaPs 1b and 2b are potentially promising alternatives vector complexes to target estrogen-dependent tissues.
  • PublicationAccès libre
    Inhibitory effects of cytoskeleton disrupting drugs and GDP-locked Rab mutants on bradykinin B2 receptor cycling
    (Academic Press, 2013-05-01) Fortin, Sébastien; Roy, Caroline; Marceau, François; Lodge, Robert; Gera, Lajos; C. Gaudreault, René.; Charest-Morin, Xavier
    The bradykinin (BK) B2 receptor (B2R) is G protein coupled and phosphorylated upon agonist stimulation; its endocytosis and recycling are documented. We assessed the effect of drugs that affect the cytoskeleton on B2R cycling. These drugs were targeted to tubulin (paclitaxel, or the novel combretastatin A-4 mimetic 3,4,5-trimethoxyphenyl-4-(2-oxoimidazolidin-1-yl)benzenesulfonate [IMZ-602]) and actin (cytochalasin D). Tubulin ligands did not alter agonist-induced receptor endocytosis, as shown using antibodies reactive with myc-tagged B2Rs (microscopy, cytofluorometry), but rather reduced the progression of the ligand–receptor–β-arrestin complex from the cell periphery to the interior. The 3 fluorescent probes of this complex (B2R-green fluorescent protein [B2R-GFP], the fluorescent agonist fluorescein-5-thiocarbamoyl-D-Arg-[Hyp3, Igl5, Oic7, Igl8]-BK and β-arrestin2–GFP) were condensed in punctuate structures that remained close to the cell surface in the presence of IMZ-602. Cytochalasin D selectively inhibited the recycling of endocytosed B2R-GFP (B2R-GFP imaging, [3H]BK binding). Dominant negative (GDP-locked)-Rab5 and -Rab11 reproduced the effects of inhibitors of tubulin and actin, respectively, on the cycling of B2R-GFP. GDP-locked-Rab4 also inhibited B2R-GFP recycling to the cell surface. Consistent with the displacement of cargo along specific cytoskeletal elements, Rab5-associated progression of the endocytosed BK B2R follows microtubules toward their (−) end, while its recycling progresses along actin fibers to the cell surface. However, tubulin ligands do not suppress the tested desensitization or resensitization mechanisms of the B2R
  • PublicationAccès libre
    Mechanism of action of N-phenyl-N'-(2-chloroethyl)ureas in the colchicine-binding site at the interface between a- and b-tubulin
    (Pergamon, 2009-04-01) Fortin, Sébastien; Wei, Lianhu; Labrie, Philippe; Petitclerc, Éric; C. Gaudreault, René.; Moreau, Emmanuel; Kotra, Lakshmi P.
    Computational tools such as CoMSIA and CoMFA models reported in a recent study revealed the structure–activity relationships ruling the interactions occurring between hydrophobic N-phenyl-N′-(2-chloroethyl)ureas (CEU) and the colchicine-binding site (C-BS) on βΙΙ-tubulin. Here, we describe the mechanisms involved in the covalent binding of three subsets of CEU derivatives to the C-BS. The FlexiDock experiments confirmed that the interaction of non-covalent portions of the CEU auxophore moiety of CEU is involved in the binding of the drug to the C-BS facilitate the nucleophilic attack of Glu-β198 rather than Cys-β239. In addition, these studies suggest that Cys-β239 together with Asn-α99, Ser-α176, Thr-α177, Leu-β246, Asn-β247, Ala-β248, Lys-β252 and Asn-β256 are implicated in the stabilization of a C-BS–CEU complex prior to the acylation of Glu-β198 by CEU. Our molecular models propose the formation of a stabilized C-BS–CEU complex before the completion of the Glu-β198 acylation; acylation triggering conformational changes of β-tubulin, microtubule depolymerization and anoikis. The computational models presented here might be useful to the design of selective and more potent C-BS inhibitors. Of interest, in vivo acylation of acidic amino acid residues by xenobiotics is an unusual reaction and may open new approaches for the design of irreversible protein inhibitors such as tubulin.
  • PublicationAccès libre
    N-Phenyl-N′-(2-chloroethyl)ureas (CEU) as potential antineoplastic agents. Part 2 : role of ω-hydroxyl group in the covalent binding to β-tubulin
    (Oxford Pergamon, 2006-11-10) Fortin, Sébastien; Rousseau, Jean; Desjardins, Michel; C. Gaudreault, René.; Patenaude, Alexandre.; Moreau, Emmanuel
    Tubulin is the target of many anticancer drugs, including N-phenyl-N′-(2-chloroethyl)urea (CEU). Unlike most anti-β-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 β-tubulin isoform-2. Following the previously synthesized and attractive N-(3-ω-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 ω-hydroxylated 1f were 2f and 3e, respectively. We have confirmed that the pentyl substituted CEUs 1f, 2f, and 3e are still covalently binding to β-tubulin and still arrest cell division in G2/M phase.
  • PublicationAccès libre
    N-Phenyl-N'-(2-chloroethyl)urea analogues of combretastatin A-4: Is the N-phenyl-N'-(2-chloroethyl)urea pharmacophore mimicking the trimethoxy phenyl moiety ?
    (2007-01-19) Fortin, Sébastien; C. Gaudreault, René.; Lacroix, Jacques; Patenaude, Alexandre.; Teulade, Jean-Claude; Moreau, Emmanuel
    A series of novel N-phenyl-N'-(2-chloroethyl)urea derivatives potentially mimicking the structure of combretastatin A-4 were synthesized and tested for their cell growth inhibition and their binding to the colchicine-binding site of beta-tubulin. Compounds 2a, 3a, and 3b were found to inhibit cell growth at the micromolar level on four human tumor cell lines. Flow cytometric analysis indicates that the new compounds act as antimitotics and arrest the cell cycle in G(2)/M phase. Covalent binding of 2a, 3a, and 3b to the colchicine-binding site of beta-tubulin was confirmed also using SDS-PAGE and competition assays.
  • PublicationAccès libre
    Activation of phenyl 4-(2-Oxo-3-alkylimidazolidin-1-yl)benzenesulfonates prodrugs by CYP1A1 as new antimitotics targeting breast cancer cells
    (American Chemical Society, 2017-05-23) Fortin, Sébastien; Gobeil, Stéphane; Turcotte, Vanessa; Côté, Marie-France; Lacroix, Jacques M.; Lauvaux, Coraline; C. Gaudreault, René.; Charest-Morin, Xavier
    Prodrug-mediated utilization of the cytochrome P450 (CYP) 1A1 to obtain the selective release of potent anticancer products within cancer tissues is a promising approach in chemotherapy. We herein report the rationale, preparation, biological evaluation and mechanism of action of phenyl 4-(2-oxo-3-alkylimidazolidin-1-yl)benzenesulfonates (PAIB-SOs), that are antimicrotubule prodrugs activated by CYP1A1. Although PAIBSOs are inert in most cells tested, they are highly cytocidal towards several human breast cancer cells, including hormone-independent and chemoresistant types. PAIB-SOs are Ndealkylated into cytotoxic phenyl 4-(2-oxo-3-imidazolidin-1-yl)benzenesulfonates (PIBSOs) in CYP1A1-positive cancer cells, both in vitro and in vivo. In conclusion, PAIBSOs are novel chemotherapeutic prodrugs with no equivalent among current antineoplastics, and whose selective action toward breast cancer is tailored to the characteristic pattern of CYP1A1 expression observed in a large percentage of human breast tumors.