Personne :
Poirier, Donald

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Structures organisationnelles
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Université Laval. Département de médecine moléculaire
Identifiant Canadiana

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Voici les éléments 1 - 4 sur 4
  • Publication
    Accès libre
    Oxidative activity of 17β-hydroxysteroid dehydrogenase on testosterone in male abdominal adipose tissues and cellular localization of 17β-HSD type 2
    (North-Holland, 2015-06-26) Fouad Mansour, Mohamed; Boulet, Marie Michèle; Poirier, Donald; Luu The, Van; Brochu, Gaétan; Cianflone, Katherine M.; Lebel, Stefane; Pelletier, Mélissa; Fradette, Julie; Tchernof, André; Mayrand, Dominique
    Testosterone can be converted into androstenedione (4-dione) by 17β-hydroxysteroid dehydrogenase (HSD) activity likely performed by 17β-HSD type 2. Our objective was to evaluate the rate of testosterone conversion to 4-dione as well as expression and localization of 17β-HSD type 2 in omental (OM) vs. subcutaneous (SC) adipose tissues of men. Formation of 4-dione from testosterone was significantly higher in homogenates (p ≤ 0.001) and explants (p ≤ 0.01) of OM than SC tissue. Microscopy analyses and biochemical assays in cell fractions localized the enzyme in the vasculature/endothelial cells of adipose tissues. Conversion of testosterone to 4-dione was weakly detected in most OM and/or SC preadipocyte cultures. Positive correlations were found between 17β-HSD type 2 activity in whole tissue and BMI or SC adipocyte diameter. We conclude that conversion of testosterone to 4-dione detected in abdominal adipose tissue is caused by 17β-HSD type 2 which is localized in the vasculature of the adipose compartment.
  • Publication
    Synergistic control of sex hormones by 17b-HSD type 7 : a novel target for estrogen-dependent breast cancer
    (Oxford University Press, 2015-05-12) Poirier, Donald; Wang, Xiao Qiang; Gérard, Catherine; Lin, Sheng-Xiang; Doillon, Charles; Thériault, Jean-François
    17b-hydroxysteroid dehydrogenase (17b-HSD) type 1 is known as a critical target to block the final step of estrogen production in estrogen-dependent breast cancer. Recent confirmation of the role of dyhydroxytestosterone (DHT) in counteracting estrogen induced cell growth prompted us to study the reductive 17b-HSD type 7 (17b-HSD7), which activates estrone while markedly inactivating DHT. The role of DHTin breast cancer cell proliferationis demonstrated by its independent suppression of cell growth in the presence of a physiological concentration of estradiol (E2). Moreover, an integral analysis of a large number of clinical samples in Oncomine datasets demonstrated the overexpression of 17b-HSD7 in breast carcinoma. Inhibition of 17b-HSD7 in breast cancer cells resulted in a lower level of E2 and a higher level of DHT, successively induced regulation of cyclinD1, p21, Bcl-2, and Bik, consequently arrested cell cycle in the G0/G1 phase, and triggered apoptosis and auto-downregulation feedback of the enzyme. Such inhibition led to significant shrinkage of xenograft tumors with decreased cancer cell density and reduced 17b-HSD7 expression. Decreased plasma E2 and elevated plasma DHT levels were also found. Thus, the dual functional 17b-HSD7 is proposed as a novel target for estrogen-dependent breast cancer by regulating the balance of E2 and DHT. This demonstrates a conceptual advance on the general belief that the major role of this enzyme is in cholesterol metabolism.
  • Publication
    Introducing molecular diversity at the C20-position of pregnenolone by the formation of spiro-2-morpholinones
    (Bentham Science Publishers Ltd., 2018-06-01) Djigoue, Guy Bertrand; Poirier, Donald
    Aim and Objective: The development of small molecules that can interact with key therapeutic target represents an active field of research. Therefore, new approaches for increasing the molecular diversity of a starting material, such as a natural product, are needed. Herein, the carbonyl group present on a pregnane scaffold, or easily obtained from the oxidation of the corresponding alcohol, was used to obtain a series of diversified steroidal morpholinone derivatives. Materials and Methods: Using chemical synthesis, two levels of molecular diversity were introduced at position 20 of a C21-steroid scaffold. Nuclear magnetic resonance (NMR) spectroscopy and x-ray analysis were next used to characterize the morpholinone derivatives. Results: The C-20 carbonyl of pregnenolone was first transformed into an oxirane that reacted with an amino acid and the resulting amino alcohol was then cyclized to generate different spiro-2-morpholinones. X-ray analysis of one representative compound confirmed the 3-dimensional representation of this new family of diversified steroid derivatives. NMR analysis supported the expected structure and identified key markers of the chiral center configuration found in the 2-morpholinone moiety. Finally, the NH of the morpholinone ring was alkylated, thus increasing structural diversity. Conclusion: Considering the huge amount of building blocks (amino acids, bromobenzyl derivatives and ketones) that are commercially available, the strategy reported herein opens the door to the synthesis of diversified libraries of new compounds.
  • Publication
    Impact of structural modifications at positions 13, 16 and 17 of 16 b -( m -carbamoylbenzyl)-estradiol on 17 b -hydroxysteroid dehydrogenase type 1 inhibition and estrogenic activity
    (Pergamon, 2015-10-28) Barbeau, Xavier; Poirier, Donald; Maltais, René.; Lin, Sheng-Xiang; Lagüe, Patrick; Thériault, Jean-François; Trottier, Alexandre; Perreault, Martin
    The chemical synthesis of four stereoisomers (compounds 5a–d) of 16ß-(m-carbamoylbenzyl)-estradiol, a potent reversible inhibitor of 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD1), and two intermediates (compounds 3a and b) was performed. Assignment of all nuclear magnetic resonance signals confirmed the stereochemistry at positions 13, 16 and 17. Nuclear overhauser effects showed clear correlations supporting a C-ring chair conformation for 5a and b and a C-ring boat conformation for 5c and d. These compounds were tested as 17ß-HSD1 inhibitors and to assess their proliferative activity on estrogen-sensitive breast cancer cells (T-47D) and androgen-sensitive prostate cancer cells (LAPC-4). Steroid derivative 5a showed the best inhibitory activity for the transformation of estrone to estradiol (95, 82 and 27%, at 10, 1 and 0.1 µM, respectively), but like the other isomers 5c and d, it was found to be estrogenic. The intermediate 3a, however, was weakly estrogenic at 1 µM, not at all at 0.1 µM, and showed an interesting inhibitory potency on 17ß-HSD1 (90, 59 and 22%, at 10, 1 and 0.1 µM, respectively). As expected, no compound showed an androgenic activity. The binding modes for compounds 3a and b, 5a–d and CC-156 were evaluated from molecular modeling. While the non-polar interactions were conserved for all the inhibitors in their binding to 17ß-HSD1, differences in polar interactions and in binding conformational energies correlated to the inhibitory potencies.