title: Synthesis and structure-activity relationships of TEI-9647 derivatives as Vitamin D3 antagonists.
abstract: The Vitamin D(3) lactone analogues, (23S)- and (23R)-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647 and TEI-9648) are antagonists of the 1alpha,25-dihydroxyvitamin D(3) (1alpha,25-(OH)(2)D(3)) nuclear receptor (VDR)-mediated differentiation of human leukemia (HL-60) cells. In order to clarify the structure-Vitamin D antagonistic activity relationship, we paid attention to the unique lactone moiety of TEI-9647 and TEI-9648: alpha-exo-methylene-gamma-lactone structure. We synthesized the exo-methylene-modified analogues (methylene saturated, endo-methylene, methylene-deleted, methyl-substituted, dimethyl-substituted, methylene-replaced with dimethyl and cyclopropane) and oxygen-modified analogues (oxygen atom replaced with nitrogen and carbon atom) by convergent method using palladium-catalyzed coupling reaction or direct modification of VD(3) skeleton. The antagonistic activity in HL-60 cell differentiation evaluating system of these analogues revealed that any exo-methylene-modified analogues and nitrogen analogue did not have the antagonistic activity, on the other hand carbon analogue did show. The results suggest that "alpha-exo-methylene carbonyl" structure of VD(3) side-chain is crucial for antagonistic activity. The structure is integral building block of many natural products which have interesting biological and it is thought that Michael-type addition of alpha-exo-methylene carbonyl structure with protein nucleophiles such as cysteine would play an important role for the activities. According to this theory, Michael-type reaction of TEI-9647 and TEI-9648 with cysteine residue in protein related to VDR/VDRE-mediated genomic actions such as VDR would be essential step of the antagonistic action.
authors.affiliation: TEIJIN Institute for Bio-medical Research, 4-3-2 Asahigaoka, Hino, Tokyo 191-8512, Japan. k.takenouchi@teijin.co.jp
authors.forename: Kazuya
authors.initials: K
authors.lastname: Takenouchi
authors.forename: Ryo
authors.initials: R
authors.lastname: Sogawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Manabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saitoh
authors.forename: Qingzhi
authors.initials: Q
authors.lastname: Gao
authors.forename: Daishiro
authors.initials: D
authors.lastname: Miura
authors.forename: Seiichi
authors.initials: S
authors.lastname: Ishizuka
mesh_terms: D002117:Calcitriol / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002762:Cholecalciferol / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship
chemical_list: C400545:TEI 9647; D002762:Cholecalciferol; D002117:Calcitriol