In Vivo and in Vitro Steroid Receptor Assays in the Design of Estrogen Radiopharmaceuticals

2019 ◽  
pp. 93-126 ◽  
Author(s):  
John A. Katzenellenbogen ◽  
Daniel F. Heiman ◽  
Kathryn E. Carlson ◽  
John E. Lloyd
Keyword(s):  
Steroid Receptor ◽  
Receptor Assays

scholarly journals Nuclear acceptor sites for androgen-receptor complexes in seminal-vesicle epithelium

1980 ◽  
Vol 192 (1) ◽  
pp. 41-47 ◽  
Author(s):  
M J Weinberger ◽  
C M Veneziale
Keyword(s):  
Seminal Vesicle ◽  
Nuclear Dna ◽  
Steroid Receptor ◽  
Assay Method ◽  
Scatchard Analysis ◽  
Receptor Complex ◽  
Receptor Complexes ◽  
Constant Slope

An assay method in vitro was developed and applied to quantify acceptor binding of steroid-receptor complexes in nuclei from isolated epithelium of guinea-pig seminal vesicle. Steroid-receptor complex prepared from 1-day-castrated animals was incubated with purified nuclei from 1-28 day-castrated animals in a medium containing 0.15 M-KCl. Free and bound steroid-receptor complexes were measured and the data were submitted to Scatchard analysis. With nuclei from 1-day-castrated animals the Kd for binding of cytosolic [3H]dihydrotestosterone-receptor complexes was found to be 0.83 × 10(-10) M and the capacity for binding was 0.35 pmol/mg of nuclear DNA. Scatchard analysis consistently disclosed only a single line of constant slope and gave the same kinetic constants for nuclei obtained from animals castrated up to 28 days before assay. Administration of 2 mg of dihydrotestosterone, 3 alpha-androstanediol or androsterone or 100 microgram of oestradiol-17 beta 1 h before killing of the 1-day-castrated animals that provided the nuclei resulted in a significant decrease in nuclear acceptor binding of the steroid-receptor complex compared with untreated animals. Thus our assay method disclosed nuclear acceptor sites that may be involved in responses to androgens (and oestrogens) in vivo. We conclude that there is a class of nuclear accept or sites of high affinity and limited capacity that may be occupied by steroid-receptor complexes in vivo.

The International Standard for Pituitary FSH: Collaborative study of the Standard and of four other purified human FSH preparations of differing molecular composition by bioassays, receptor assays and different immunoassay systems

1989 ◽  
Vol 123 (2) ◽  
pp. 275-293 ◽  
Author(s):  
P. L. Storring ◽  
Gaines Das R. E.
Keyword(s):  
Geometric Mean ◽  
In Vitro Bioassay ◽  
International Standard ◽  
Receptor Assay ◽  
Specific Activities ◽  
In Vivo Bioassay ◽  
Ranking Order ◽  
Receptor Assays

ABSTRACT The International Standard for Pituitary FSH (IS; in ampoules coded 83/575) was assayed in terms of the Second International Reference Preparation of Human Pituitary FSH and LH for Bioassay (IRP 78/549) by 27 laboratories in 13 countries using bioassays, receptor assays and immunoassays. Estimates of the FSH content of the IS by in-vivo bioassay were homogeneous both within and between laboratories and gave a combined geometric mean (with 95% fiducial limits) of 79·9 (74·6–85·4) i.u./ampoule. Estimates by different in-vitro bioassays and receptor assays were also homogeneous between assays and laboratories, and gave a combined geometric mean (with 95% fiducial limits) of 31·2 (28·8–33·9) i.u./ampoule. However, estimates by the 19 different immunoassay systems were heterogeneous and varied between 5 and 31 i.u./ampoule. The material in ampoules coded 83/575 was established by the World Health Organization as the International Standard for Pituitary FSH. It was assigned a unitage of 80 i.u./ampoule on the basis of its calibration by in-vivo bioassay, because this assay best identifies and defines the hormone. However, the introduction of the new IS will necessitate the recalibration of immunoassay kits. FSH 84/530, prepared in the same way as the IS from the same FSH preparation, did not differ significantly from the IS in any of the assay systems studied and appeared to be equally suitable as a standard. Four highly purified preparations of human FSH (FSH A–D), differing in their isoform compositions and in their in-vivo: in-vitro bioactivity ratios, were also studied. The ranking order of the specific activities of FSH A–D by in-vitro bioassays paralleled their order by receptor assays and the order of their content of FSH isoforms with isoelectric points > 4·5. (Potency estimates of FSH B and C in terms of the IS were greater by receptor assay than by in-vitro bioassay.) The overall ranking order of the specific activities of FSH A–D by immunoassays was different. Contrary to expectation, estimates in terms of the IS of specific activities by immunoassay differed more between preparations than those by in-vitro bioassay or receptor assay. Differences in specificity between immunoassay systems were demonstrated not only in the calibration of the IS in terms of the crude FSH of IRP 78/549 but also in the comparisons of the highly purified FSH in the IS and FSH A–D. The differences in the immunoreactivities and bioactivities of FSH preparations differing in their isoform compositions greatly complicate the standardization of assays for FSH. Journal of Endocrinology (1989) 123, 275–293

scholarly journals MOLECULAR DOCKING STUDY ON 1H-(3,4d) PYRAZOLO-PYRIMIDINES AS CYCLIN DEPENDANT KINASE (CDK2) INHIBITORS

2016 ◽  
Vol 9 (1) ◽  
pp. 94
Author(s):  
Manisha S. Phoujdar ◽  
Gourishankar R. Aland
Keyword(s):  
Data Bank ◽  
Docking Study ◽  
Docking Studies ◽  
Van Der Waals Interactions ◽  
Binding Modes ◽  
Molecular Docking Study ◽  
Discovery Studio ◽  
Receptor Assays

Objective: CDK2 inhibitors are implicated in several carcinomas viz. Carcinoma of lung, bladder, sarcomas and retinoblastoma. Pyrazolopyrimidines, being purine bioisosters inhibit more than one type of kinase. In this study, we are studying some novel derivatives of 1H-pyrazolo [3,4d] pyrimidines not reported earlier. The objective of the present study is an attempt towards design and development of 1H-[3,4-] pyrazolo-pyrimidines as CDK2 inhibitors through rational drug design.Methods: The present study has been done on CDK2 structure, PDB ID, 3WBL, co-crystallized with ligand PDY from RCSB protein data bank. A series of seventeen 1H-Pyrazolo [3,4-d] pyrimidines feasible for synthesis was docked on the said CDK2 receptor using Auto Dock 4 version, 1.5.6. Outputs were exported to discovery studio 3.5 client for visual inspection of the binding modes and interactions of the compounds with amino acid residues in the active sites.Results: The results of docking studies revealed that the present series of 1H-Pyrazolo[3,4-d] pyrimidines is showing significant binding through hydrogen bonding, hydrophobic, pi and Van der waals interactions, similar to the ligand PDY. Some conserved H-bond interactions comparable to bioisosters and compounds presently under human trials were noted. Ki values predicted in silico also suggest that the series will show promising CDK2 inhibitory activity.Conclusion: The series designed and docked can be further developed by synthesis and in vitro and in vivo activity. The receptor inhibitory activity can also be checked by specific receptor assays.

scholarly journals In Vivo Resistance to Glucocorticoid-Induced Apoptosis in Rat Thymocytes with Normal Steroid Receptor Function in Vitro

Endocrinology ◽  
1997 ◽  
Vol 138 (2) ◽  
pp. 810-818 ◽  
Author(s):  
Nicklas B. E. Oldenburg ◽  
Rosemary B. Evans-Storms ◽  
John A. Cidlowski
Keyword(s):  
Steroid Receptor ◽  
Receptor Function ◽  
Induced Apoptosis

scholarly journals In Vivo Interaction of Steroid Receptor Coactivator (SRC)-1 and the Activation Function-2 Domain of the Thyroid Hormone Receptor (TR) β in TRβ E457A Knock-In and SRC-1 Knockout mice

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3927-3934 ◽  
Author(s):  
Manuela Alonso ◽  
Charles Goodwin ◽  
XiaoHui Liao ◽  
Tania Ortiga-Carvalho ◽  
Danielle S. Machado ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormone Receptor ◽  
Steroid Receptor ◽  
Activation Function ◽  
Steroid Receptor Coactivator ◽  
Pituitary Thyroid Axis ◽  
Serum T4 ◽  
Thyroid Axis

The activation function-2 (AF-2) domain of the thyroid hormone (TH) receptor (TR)-β is a TH-dependent binding site for nuclear coactivators (NCoA), which modulate TH-dependent gene transcription. In contrast, the putative AF-1 domain is a TH-independent region interacting with NCoA. We determined the specificity of the AF-2 domain and NCoA interaction by evaluating thyroid function in mice with combined disruption of the AF-2 domain in TRβ, due to a point mutation (E457A), and deletion of one of the NCoAs, steroid receptor coactivator (SRC)-1. The E457A mutation was chosen because it abolishes NCoA recruitment in vitro while preserving normal TH binding and corepressor interactions resulting in resistance to TH. At baseline, disruption of SRC-1 in the homozygous knock-in (TRβE457A/E457A) mice worsened the degree of resistance to TH, resulting in increased serum T4 and TSH. During TH deprivation, disruption of AF-2 and SRC-1 resulted in a TSH rise 50% of what was seen when AF-2 alone was removed, suggesting that SRC-1 was interacting outside of the AF-2 domain. Therefore, 1) during TH deprivation, SRC-1 is necessary for activating the hypothalamic-pituitary-thyroid axis; 2) ligand-dependent repression of TSH requires an intact AF-2; and 3) SRC-1 may interact with the another region of the TRβ or the TRα to regulate TH action in the pituitary. This report demonstrates the dual interaction of NCoA in vivo: the TH-independent up-regulation possibly through another domain and TH-dependent down-regulation through the AF-2 domain.

scholarly journals Genetic dissection of the signaling domain of a mammalian steroid receptor in yeast.

1992 ◽  
Vol 3 (11) ◽  
pp. 1245-1257 ◽  
Author(s):  
M J Garabedian ◽  
K R Yamamoto
Keyword(s):  
Signal Transduction ◽  
Glucocorticoid Receptor ◽  
Mammalian Cells ◽  
Rank Order ◽  
Point Mutations ◽  
Steroid Receptor ◽  
Genetic Dissection ◽  
Signaling Domain

The mechanism of signal transduction by steroid receptor proteins is complex and not yet understood. We describe here a facile genetic strategy for dissection of the rat glucocorticoid receptor "signaling domain," a region of the protein that binds and transduces the hormonal signal. We found that the characteristics of signal transduction by the receptor expressed in yeast were similar to those of endogenous receptors in mammalian cells. Interestingly, the rank order of particular ligands differed between species with respect to receptor binding and biological efficacy. This suggests that factors in addition to the receptor alone must determine or influence ligand efficacy in vivo. To obtain a collection of receptors with distinct defects in signal transduction, we screened in yeast an extensive series of random point mutations introduced in that region in vitro. Three phenotypic classes were obtained: one group failed to bind hormone, a second displayed altered ligand specificity, and a third bound hormone but lacked regulatory activity. Our results demonstrate that analysis of glucocorticoid receptor action in yeast provides a general approach for analyzing the mechanism of signaling by the nuclear receptor family and may facilitate identification of non-receptor factors that participate in this process.

scholarly journals Essential Role for Co-chaperone Fkbp52 but Not Fkbp51 in Androgen Receptor-mediated Signaling and Physiology

2006 ◽  
Vol 282 (7) ◽  
pp. 5026-5036 ◽  
Author(s):  
Weidong Yong ◽  
Zuocheng Yang ◽  
Sumudra Periyasamy ◽  
Hanying Chen ◽  
Selcul Yucel ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Nuclear Translocation ◽  
Steroid Receptor ◽  
Hormone Binding ◽  
Receptor Complexes ◽  
Deficient Mice

Fkbp52 and Fkbp51 are tetratricopeptide repeat proteins found in steroid receptor complexes, and Fkbp51 is an androgen receptor (AR) target gene. Although in vitro studies suggest that Fkbp52 and Fkbp51 regulate hormone binding and/or subcellular trafficking of receptors, the roles of Fkbp52 and Fkbp51 in vivo have not been extensively investigated. Here, we evaluate their physiological roles in Fkbp52-deficient and Fkbp51-deficient mice. Fkbp52-deficient males developed defects in select reproductive organs (e.g. penile hypospadias and prostate dysgenesis but normal testis), pointing to a role for Fkbp52 in AR-mediated signaling and function. Surprisingly, ablation of Fkbp52 did not affect AR hormone binding or nuclear translocation in vivo and in vitro. Molecular studies in mouse embryonic fibroblast cells uncovered that Fkbp52 is critical to AR transcriptional activity. Interestingly, Fkbp51 expression was down-regulated in Fkbp52-deficient males but only in affected tissues, providing further evidence of tissue-specific loss of AR activity and suggesting that Fkbp51 is an AR target gene essential to penile and prostate development. However, Fkbp51-deficient mice were normal, showing no defects in AR-mediated reproductive function. Our work demonstrates that Fkbp52 but not Fkbp51 is essential to AR-mediated signaling and provides evidence for an unprecedented Fkbp52 function, direct control of steroid receptor transcriptional activity.

scholarly journals Conditionally reprogrammed macaque endocervical cells retain steroid receptor expression and produce mucus

2020 ◽  
Vol 102 (6) ◽  
pp. 1191-1202
Author(s):  
Leo Han ◽  
Walker Andrews ◽  
Karsten Wong ◽  
Jeffrey T Jensen
Keyword(s):  
Kinase Inhibitor ◽  
Rhesus Macaques ◽  
Cell Types ◽  
Steroid Receptor ◽  
Cervical Mucus ◽  
Receptor Expression ◽  
Proliferative Potential ◽  
Steroid Receptor Expression

Abstract Cervical mucus produced by the endocervix plays an essential role as a hormonally induced regulator of female fertility. Cervical mucus fluctuates in both physical characteristics and in sperm penetrability in response to estrogens and progestogens. However, the mechanisms by which steroid hormones change mucus remains poorly understood. Current in vitro models have limited capability to study these questions as primary endocervical cells possess limited expansion potential, and immortalized cells lose in vivo characteristics such as steroid sensitivity. Here we overcome these limitations by establishing an in vitro primary endocervical cell culture model using conditionally reprogrammed cells (CRCs). CRC culture utilizes a Rho-kinase inhibitor and a fibroblast feeder layer to expand proliferative potential of epithelial cell types that have normally short in vitro life spans. In our studies, we produce CRC cultures using primary endocervical cells from adult female rhesus macaques (Macaca mulatta). We demonstrate that primary endocervical cells from the nonhuman primate can be robustly expanded using a CRC method, while retaining steroid receptor expression. Moreover, when removed from CRC conditions and switched to differentiation conditions, these cells are able to differentiate and produce mucus including MUC5B, the most prevalent mucin of the endocervix. We conclude that this method provides a promising in vitro platform for conducting mechanistic studies of cervical mucus regulation as well as for screening new therapeutic targets for fertility regulation and diseases of the endocervix.

scholarly journals Peptidyl-Prolyl Isomerase 1 (Pin1) Serves as a Coactivator of Steroid Receptor by Regulating the Activity of Phosphorylated Steroid Receptor Coactivator 3 (SRC-3/AIB1)

2005 ◽  
Vol 25 (21) ◽  
pp. 9687-9699 ◽  
Author(s):  
Ping Yi ◽  
Ray-Chang Wu ◽  
Joshua Sandquist ◽  
Jiemin Wong ◽  
Sophia Y. Tsai ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Intracellular Signaling ◽  
Steroid Receptors ◽  
Steroid Receptor ◽  
Dependent Manner ◽  
Prolyl Isomerase ◽  
Peptidyl Prolyl Isomerase ◽  
Steroid Receptor Coactivator

ABSTRACT Steroid receptor coactivator 3 (SRC-3/AIB1) interacts with steroid receptors in a ligand-dependent manner to activate receptor-mediated transcription. A number of intracellular signaling pathways initiated by growth factors and hormones induce phosphorylation of SRC-3, regulating its function and contributing to its oncogenic potential. However, the range of mechanisms by which phosphorylation affects coactivator function remains largely undefined. We demonstrate here that peptidyl-prolyl isomerase 1 (Pin1), which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds to induce conformational changes of its target proteins, interacts selectively with phosphorylated SRC-3. In addition, Pin1 and SRC-3 activate nuclear-receptor-regulated transcription synergistically. Depletion of Pin1 by small interfering RNA (siRNA) reduces hormone-dependent transcription from both transfected reporters and an endogenous steroid receptor target gene. We present evidence that Pin1 modulates interactions between SRC-3 and CBP/p300. The interaction is enhanced in vitro and in vivo by Pin1 and diminished when cellular Pin1 is reduced by siRNA or in stable Pin1-depleted cell lines. Depletion of Pin1 in MCF-7 human breast cancer cells reduces the endogenous estrogen-dependent recruitment of p300 to the promoters of estrogen receptor-dependent genes. Pin1 overexpression enhanced SRC-3 cellular turnover, and depletion of Pin1 stabilized SRC-3. Our results suggest that Pin1 functions as a transcriptional coactivator of nuclear receptors by modulating SRC-3 coactivator protein-protein complex formation and ultimately by also promoting the turnover of the activated SRC-3 oncoprotein.

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