RRC ID 1457
Author Ochiai E, Miura D, Eguchi H, Ohara S, Takenouchi K, Azuma Y, Kamimura T, Norman AW, Ishizuka S.
Title Molecular mechanism of the vitamin D antagonistic actions of (23S)-25-dehydro-1alpha-hydroxyvitamin D3-26,23-lactone depends on the primary structure of the carboxyl-terminal region of the vitamin d receptor.
Journal Mol. Endocrinol.
Abstract We reported that (23S)-25-dehydro-1alpha-hydroxyvitamin D(3)-26,23-lactone (TEI-9647) antagonizes vitamin D receptor (VDR)-mediated genomic actions of 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)] in human cells but is agonistic in rodent cells. Human and rat VDR ligand-binding domains are similar, but differences in the C-terminal region are important for ligand binding and transactivation and might determine the agonistic/antagonistic effects of TEI-9647. We tested TEI-9647 on 1alpha,25(OH)(2)D(3) transactivation using SaOS-2 cells (human osteosarcoma) or ROS 24/1 cells (rat osteosarcoma) cotransfected with human or rodent VDR and a reporter. In both cell lines, TEI-9647 was antagonistic with wild-type human (h)VDR, but agonistic with overexpressed wild-type rat (r)VDR. VDR chimeras substituting the hVDR C-terminal region (activation function 2 domain) with corresponding rVDR residues diminished antagonism and increased agonism of TEI-9647. However, substitution of 25 C-terminal rVDR residues with corresponding hVDR residues diminished agonism and increased antagonism of TEI-9647. hVDR mutants (C403S, C410N) demonstrated that Cys403 and/or 410 was necessary for TEI-9647 antagonism of 1alpha,25(OH)(2)D(3) transactivation. These results suggest that species specificity of VDR, especially in the C-terminal region, determines the agonistic/antagonistic effects of TEI-9647 that determine, in part, VDR interactions with coactivators and emphasize the critical interaction between TEI-9647 and the two C-terminal hVDR Cys residues to mediate the antagonistic effect of TEI-9647.
Volume 19(5)
Pages 1147-57
Published 2005-5
DOI 10.1210/me.2004-0234
PII me.2004-0234
PMID 15650022
MeSH Amino Acid Sequence Animals Calcitriol / analogs & derivatives* Calcitriol / pharmacology* Cysteine / metabolism Humans Lactones / metabolism* Molecular Sequence Data Osteosarcoma / metabolism Rats Receptors, Calcitriol / metabolism* Species Specificity Vitamin D / agonists Vitamin D / antagonists & inhibitors*
IF 3.628
Times Cited 29
Human and Animal Cells ROS-17/2.8-5