ABSTRACT
The synthesis and structure-activity relationships of novel dipeptidyl peptidase IV inhibitors replacing the classical cyanopyrrolidine P1 group with other small nitrogen heterocycles are described. A unique potency enhancement was achieved with beta-branched natural and unnatural amino acids, particularly adamantylglycines, linked to a (2S,3R)-2,3-methanopyrrolidine based scaffold.
Subject(s)
Dipeptides/chemistry , Dipeptidyl-Peptidase IV Inhibitors , Dipeptidyl-Peptidase IV Inhibitors/chemistry , Dipeptides/pharmacology , Dipeptidyl-Peptidase IV Inhibitors/pharmacology , Drug Evaluation, Preclinical , Humans , Nitriles/chemistry , Nitriles/pharmacology , Structure-Activity RelationshipABSTRACT
On the basis of the stucture of genistein, a new series of 3-arylquinazolines was prepared and tested for their estrogen receptor (ER) alpha and beta affinities. 5,7-Dihydroxy-3-(4-hydroxyphenyl)-4(3H)-quinazolinone (1aa) acts as an agonist on both ER subtypes. It has 62-fold higher binding affinity [IC(50)(ERbeta) = 179 nM] and 38-fold higher functional potency in a transcription assay [EC(50)(ERbeta) = 76 nM] with ERbeta than with ERalpha, thus improving upon the selectivity of genistein. All of the analogues showed preferential binding affinity for ERbeta. Many are also more potent in activating transcription by ERbeta than by ERalpha. Transformation of the C=O functionality at position 4 into a C=S group provided 5,7-dihydroxy-3-(4-hydroxyphenyl)-4(3H)-quinazolinethione (1ba), which acts as an agonist on both ER subtypes but has 56-fold higher binding affinity for ERbeta over ERalpha [IC(50)(ERbeta) = 47 nM] and 215-fold higher potency in the transcription assay [EC(50)(ERbeta) = 13 nM]. These ERbeta-selective compounds may represent valuable tools in understanding the differences in structure and biological function of ERbeta and ERalpha.
Subject(s)
Estrogen Receptor Modulators/chemistry , Estrogen Receptor alpha/agonists , Estrogen Receptor beta/agonists , Quinazolines/chemistry , Thiones/chemistry , Binding Sites , Binding, Competitive , Estrogen Receptor Modulators/chemical synthesis , Estrogen Receptor Modulators/pharmacology , Estrogen Receptor alpha/chemistry , Estrogen Receptor beta/chemistry , Molecular Structure , Quinazolines/chemical synthesis , Quinazolines/pharmacology , Quinazolinones , Stereoisomerism , Structure-Activity Relationship , Thiones/chemical synthesis , Thiones/pharmacologyABSTRACT
A series of 3-aryl-7-hydroxybenzoxazine analogues have been prepared and evaluated as ligands for the two estrogen receptor subtypes (ERalpha and ERbeta). From the radioligand binding assay, compounds with more than a 10-fold binding selectivity toward the ERbeta subtype have been identified. These compounds have also been shown to be potent full agonists in the functional assay by activation of ERE promoted transcription, with the best compound being 20-fold more potent than genistein.
Subject(s)
Benzoxazines/chemistry , Benzoxazines/pharmacology , Estrogen Receptor beta/agonists , Benzoxazines/chemical synthesis , Static Electricity , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Statins, which are inhibitors of 3-hydroxy-3-glutaryl-coenzyme A (HMG-CoA) reductase, decrease the hepatic biosynthesis of cholesterol by blocking the mevalonate pathway. Nitrogen-containing bisphosphonate drugs also inhibit the mevalonate pathway, preventing the production of the isoprenoids, which consequently results in the inhibition of osteoclast formation and osteoclast function. Therefore, we hypothesized that statins could affect bone metabolism in vivo through effects on osteoclastic bone resorption. In vitro, cerivastatin inhibited the parathyroid hormone (PTH)-stimulated bone resorption. Using a panel of 40 statin analogs, which showed variable effects on HMG-CoA reductase activity, we found that the ability of compounds to inhibit bone resorption is directly related to HMG-CoA reductase activity. However, in the thyro-parathyrodectomy (TPTX) model for bone resorption in the rat in vivo, cerivastatin did not prevent experimentally induced increases in bone resorption. The lack of effect of cerivastatin in this model is not related to a limited penetration of the target tissue (bone marrow), because a significant effect on HMG-CoA reductase activity was demonstrated in the total rat bone marrow cell extracts of rats posttreatment in vivo. Furthermore, cerivastatin inhibited protein prenylation in osteoclasts isolated from the rabbit bone marrow of rabbits after treatment in vivo. In contrast to other studies, none of the statins tested showed anabolic effects in parietal bone explant cultures. Taken together, we conclude that statins inhibit bone resorption in vitro, which correlates directly with the potency of the compounds for inhibition of HMG-CoA reductase activity. However, cerivastatin does not affect bone resorption in the rat TPTX model in vivo.
