title: Chemical synthesis of 16beta-propylaminoacyl derivatives of estradiol and their inhibitory potency on type 1 17beta-hydroxysteroid dehydrogenase and binding affinity on steroid receptors.
abstract: The 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) are members of a family of enzymes that catalyze the interconversion of weakly active sexual hormones (ketosteroids) and potent hormones (17beta-hydroxysteroids). Among the known isoforms of 17beta-HSD, the type 1 catalyzes the NAD(P)H-mediated reduction of estrone (E(1)) to estradiol (E(2)), a predominant mitogen for the breast cancer cells. Therefore, the inhibition of this particular enzyme is a logical approach to reduce the concentration of estradiol in breast tumors. To develop inhibitors of type 1 17beta-HSD activity, we hypothesized that molecules containing both hydrophobic and hydrophilic components should be interesting candidates for interacting with both the steroid binding domain and some amino acid residues of the cofactor binding domain of the enzyme. Firstly, a conveniently protected 16beta-(3-aminopropyl)-E(2) derivative was synthesized from commercially available E(1). Then, a representative of all class of NHBoc-protected amino acids (basic, acid, aromatic, aliphatic, hydroxylated) were coupled using standard procedures to the amino group of the precursor. Finally, cleavage of all protecting groups was performed in a single step to generate a series of 16beta-propylaminoacyl derivatives of E(2). The enzymatic screening revealed that none of the novel compounds can inhibit the reductive activity of type 1 17beta-HSD. On the other hand, all of these E(2) derivatives did not show any significant binding affinity on four steroid receptors including the estrogen receptor. Additional efforts aimed at improving the inhibitory potency of these steroidal derivatives on type 1 17beta-HSD without providing estrogenic activities is under investigation using a combinatorial chemistry approach.
authors.affiliation: Medicinal Chemistry Division, Oncology and Molecular Endocrinology Research Center, Laval University Medical Center (CHUL), 2705 Laurier Boulevard, Sainte-Foy, Quebec G1V 4G2, Canada.
authors.forename: M R
authors.initials: MR
authors.lastname: Tremblay
authors.forename: S X
authors.initials: SX
authors.lastname: Lin
authors.forename: D
authors.initials: D
authors.lastname: Poirier
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors*; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D001943:Breast Neoplasms / Q000139:chemically induced; D002478:Cells, Cultured / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology*; D004958:Estradiol / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology; D004967:Estrogens / Q000009:adverse effects; D006801:Humans; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D051381:Rats; D011987:Receptors, Steroid / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D004967:Estrogens; D011987:Receptors, Steroid; D009243:NAD; D004958:Estradiol; D009249:NADP; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase