title: Structural elucidation of Leuprolide and its analogues in solution: insight into their bioactive conformation.
abstract: Leuprolide [DLeu6, NHEt10]GnRH, a potent gonadotropin-releasing hormone (GnRH) agonist, is used in a wide variety of hormone-related diseases like cancer and endometriosis. In this report, the conformational behaviour of Leuprolide and its linear synthetic analogues, namely [Tyr5(OMe), DLeu6, Aze9, NHEt10]GnRH (1) and [Tyr5(OMe), DLeu6, NHEt10]GnRH (2) have been studied in DMSO and H2O solutions by means of 2D nuclear magnetic resonance (NMR) experiments and detailed molecular dynamics (MD) simulations. The aim was to identify the conformational requirements of GnRH analogues for agonistic activity. This approach is of value as no crystallographic data are available for the GnRH receptor (G protein-coupled receptor, GPCR). The NOE data indicate the existence of a β-turn type I in the 2-5 segments of Leuprolide and its linear analogues in the case of using DMSO-d6 as solvent, whereas a β-turn type II in the 3-6 segments is indicated using D2O as solvent. The final structures fulfil the conformational requirements that are known, in the literature, to play a significant role in receptor recognition and activation. Finally, the linear analogues (1) and (2) are biologically active when tested against the human breast cancer cell line, MCF-7.
authors.affiliation: Department of Chemistry, University of Patras, Patras, 26500, Greece.
authors.forename: Despina K
authors.initials: DK
authors.lastname: Laimou
authors.forename: Maria
authors.initials: M
authors.lastname: Katsara
authors.forename: Minos-Timotheos I
authors.initials: MT
authors.lastname: Matsoukas
authors.forename: Vasso
authors.initials: V
authors.lastname: Apostolopoulos
authors.forename: Anastassios N
authors.initials: AN
authors.lastname: Troganis
authors.forename: Theodore V
authors.initials: TV
authors.lastname: Tselios
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists; D006801:Humans; D016729:Leuprolide / Q000031:analogs & derivatives / Q000737:chemistry* / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D012996:Solutions; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D014867:Water / Q000737:chemistry
chemical_list: D018931:Antineoplastic Agents, Hormonal; D012996:Solutions; D014867:Water; D007987:Gonadotropin-Releasing Hormone; D016729:Leuprolide; D004121:Dimethyl Sulfoxide