Selective Glucocorticoid Receptor Antagonist Research Articles

Glucocorticoid receptor antagonist CORT113176 attenuates motor and neuropathological symptoms of Huntington's disease in R6/2 mice

Huntington's Disease (HD) is a progressive neurodegenerative disease caused by a mutation in the huntingtin gene. The mutation leads to a toxic gain of function of the mutant huntingtin (mHtt) protein resulting in cellular malfunction, aberrant huntingtin aggregation and eventually neuronal cell death. Patients with HD show impaired motor functions and cognitive decline. Elevated levels of glucocorticoids have been found in HD patients and in HD mouse models, and there is a positive correlation between increased glucocorticoid levels and the progression of HD. Therefore, antagonism of the glucocorticoid receptor (GR) may be an interesting strategy for the treatment of HD. In this study, we evaluated the efficacy of the selective GR antagonist CORT113176 in the commonly used R6/2 mouse model. In male mice, CORT113176 treatment significantly delayed the loss of grip strength, the development of hindlimb clasping, gait abnormalities, and the occurrence of epileptic seizures. CORT113176 treatment delayed loss of DARPP-32 immunoreactivity in the dorsolateral striatum. It also restored HD-related parameters including astrocyte markers in both the dorsolateral striatum and the hippocampus, and microglia markers in the hippocampus. This suggests that CORT113176 has both cell-type and brain region-specific effects. CORT113176 delayed the formation of mHtt aggregates in the striatum and the hippocampus. In female mice, we did not observe major effects of CORT113176 treatment on HD-related symptoms, with the exception of the anti-epileptic effects. We conclude that CORT113176 effectively delays several key symptoms related to the HD phenotype in male R6/2 mice and believe that GR antagonism may be a possible treatment option.

Glucocorticoid Receptor Antagonism Improves Glucose Metabolism in a Mouse Model of Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with obesity, insulin resistance, and dyslipidemia. Hyperandrogenism is a major characteristic of PCOS. Increased androgen exposure is believed to deregulate metabolic processes in various tissues as part of the PCOS pathogenesis, predominantly through the androgen receptor (AR). Notably, various metabolic features in PCOS are similar to those observed after excess glucocorticoid exposure. We hypothesized that glucocorticoid receptor (GR) signaling is involved in the metabolic symptoms of PCOS. In a PCOS model of chronic dihydrotestosterone (DHT) exposure in female mice, we investigated whether GR signaling machinery was (de)regulated, and if treatment with a selective GR antagonist alleviated the metabolic symptoms. We observed an upregulation of GR messenger RNA expression in the liver after DHT exposure. In white adipose tissues and liver we found that DHT upregulated Hsd11b1, which encodes for the enzyme that converts inactive into active glucocorticoids. We found that preventive but not therapeutic administration of a GR antagonist alleviated DHT-induced hyperglycemia and restored glucose tolerance. We did not observe strong effects of GR antagonism in DHT-exposed mice on other features like total fat mass and lipid accumulation in various tissues. We conclude that GR activation may play a role in glucose metabolism in DHT-exposed mice.

Cortisol/glucocorticoid receptor: a critical mediator of the ovulatory process and luteinization in human periovulatory follicles.

Do cortisol/glucocorticoid receptors play an active role in the human ovary during ovulation and early luteinization? The ovulatory hCG stimulation-induced glucocorticoid receptor signaling plays a crucial role in regulating steroidogenesis and ovulatory cascade in human periovulatory follicles. Previous studies reported an increase in cortisol levels in the human follicular fluid after the LH surge or ovulatory hCG administration. However, little is known about the role of cortisol/glucocorticoid receptors in the ovulatory process and luteinization in humans. This study was an experimental prospective clinical and laboratory-based study. An in vivo experimental study was accomplished utilizing the dominant ovarian follicles from 38 premenopausal women undergoing laparoscopic sterilization. An in vitro experimental study was completed using the primary human granulosa/lutein cells (hGLC) from 26 premenopausal women undergoing IVF. This study was conducted in a private fertility clinic and academic medical centers. Dominant ovarian follicles were collected before the LH surge and at defined times after hCG administration from women undergoing laparoscopic sterilization. Primary hGLC were collected from women undergoing IVF. hGLC were treated without or with hCG in the absence or presence of RU486 (20 µM; dual antagonist for progesterone receptor and glucocorticoid receptor) or CORT125281 (50 µM; selective glucocorticoid receptor antagonist) for 12 or 36 h. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and ovulatory cascade was studied with RT-quantitative PCR and western blotting. The production of cortisol, corticosterone, and progesterone was assessed by hormone assay kits. hCG administration upregulated the expression of hydroxysteroid 11-beta dehydrogenase 1 (HSD11B1), nuclear receptor subfamily 3 group C member 1 (NR3C1), FKBP prolyl isomerase 5 (FKBP5), and FKBP prolyl isomerase 4 (FKBP4) in human ovulatory follicles and in hGLC (P < 0.05). RU486 and CORT125281 reduced hCG-induced increases in progesterone and cortisol production in hGLC. The expression of genes involved in glucocorticoid receptor signaling, steroidogenesis, and the key ovulatory process was reduced by RU486 and/or CORT125281 in hGLC. N/A. The role of cortisol/glucocorticoid receptors demonstrated using the hGLC model may not fully reflect their physiological roles in vivo. Successful ovulation and luteinization are essential for female fertility. Women with dysregulated cortisol levels often suffer from anovulatory infertility. Deciphering the functional role of glucocorticoid receptor signaling in human periovulatory follicles enhances our knowledge of basic ovarian physiology and may provide therapeutic insights into treating infertility in women. This study was supported by P01HD71875 (to M.J., T.E.C., and M.B.) and R01HD096077 (to M.J.) from the Foundation for the National Institutes of Health and the BTPSRF of the University of Kentucky Markey Cancer Center (P30CA177558). The authors report no competing interests. N/A.

Peripheral glucocorticoid receptor antagonism by relacorilant with modest HPA axis disinhibition.

Glucocorticoid stress hormones are produced in response to hypothalamic-pituitary-adrenal (HPA) axis activation. Glucocorticoids are essential for physiology and exert numerous actions via binding to the glucocorticoid receptor (GR). Relacorilant is a highly selective GR antagonist currently undergoing a phase 3 clinical evaluation for the treatment of endogenous Cushing's syndrome. It was found that increases in serum adrenocorticotropic hormone (ACTH) and cortisol concentrations after relacorilant treatment were substantially less than the increases typically observed with mifepristone, but it is unclear what underlies these differences. In this study, we set out to further preclinically characterize relacorilant in comparison to the classical but non-selective GR antagonist mifepristone. In human HEK-293 cells, relacorilant potently antagonized dexamethasone- and cortisol-induced GR signaling, and in human peripheral blood mononuclear cells, relacorilant largely prevented the anti-inflammatory effects of dexamethasone. In mice, relacorilant treatment prevented hyperinsulinemia and immunosuppression caused by increased corticosterone exposure. Relacorilant treatment reduced the expression of classical GR target genes in peripheral tissues but not in the brain. In mice, relacorilant induced a modest disinhibition of the HPA axis as compared to mifepristone. In line with this, in mouse pituitary cells, relacorilant was generally less potent than mifepristone in regulating Pomc mRNA and ACTH release. This contrast between relacorilant and mifepristone is possibly due to the distinct transcriptional coregulator recruitment by the GR. In conclusion, relacorilant is thus an efficacious peripheral GR antagonist in mice with only modest disinhibition of the HPA axis, and the distinct properties of relacorilant endorse the potential of selective GR antagonist treatment for endogenous Cushing's syndrome.

Chronic stress-driven glucocorticoid receptor activation programs key cell phenotypes and functional epigenomic patterns in human fibroblasts

SummaryChronic environmental stress can profoundly impact cell and body function. Although the underlying mechanisms are poorly understood, epigenetics has emerged as a key link between environment and health. The genomic effects of stress are thought to be mediated by the action of glucocorticoid stress hormones, primarily cortisol in humans, which act via the glucocorticoid receptor (GR). To dissect how chronic stress-driven GR activation influences epigenetic and cell states, human fibroblasts underwent prolonged exposure to physiological stress levels of cortisol and/or a selective GR antagonist. Cortisol was found to drive robust changes in cell proliferation, migration, and morphology, which were abrogated by concomitant GR blockade. The GR-driven cell phenotypes were accompanied by widespread, yet genomic context-dependent, changes in DNA methylation and mRNA expression, including gene loci with known roles in cell proliferation and migration. These findings provide insights into how chronic stress-driven functional epigenomic patterns become established to shape key cell phenotypes.

Corticosterone Levels and Glucocorticoid Receptor Gene Expression in High Drinking in the Dark Mice and Their Heterogeneous Stock (HS/NPT) Founder Line

The High Drinking in the Dark (HDID-1) line of mice has been selectively bred for achieving high blood alcohol levels (BALs) in the Drinking in the Dark task, a model of binge-like drinking. Recently, we determined that glucocorticoid receptor (GR) antagonism with either mifepristone or CORT113176 (a selective GR antagonist) reduced binge-like ethanol intake in the HDID-1 mice, but not in their founder line, HS/NPT. Here, we examined whether the selection process may have altered glucocorticoid functioning by measuring (1) plasma corticosterone levels and (2) expression of the genes encoding GR (Nr3c1) and two of its chaperone proteins FKBP51 and FKBP52 (Fkbp5 and Fkbp4) in the brains (nucleus accumbens, NAc) of HDID-1 and HS/NPT mice. We observed no genotype differences in baseline circulating corticosterone levels. However, HDID-1 mice exhibited a greater stimulated peak corticosterone response to an IP injection (of either ethanol or saline) relative to their founder line. We further observed reduced basal expression of Fkbp4 and Nr3c1 in the NAc of HDID-1 mice relative to HS/NPT mice. Finally, HDID-1 mice exhibited reduced Fkbp5 expression in the NAc relative to HS/NPT mice following an injection of 2 g/kg ethanol. Together, these data suggest that selective breeding for high BALs may have altered stress signaling in the HDID-1 mice, which may contribute to the observed selective efficacy of GR antagonism in reducing binge-like ethanol intake in HDID-1, but not HS/NPT mice. These data have important implications for the role that stress signaling plays in the genetic risk for binge drinking.

Alcohol dependence and withdrawal increase sensitivity of central amygdalar GABAergic synapses to the glucocorticoid receptor antagonist mifepristone in male rats

Aberrant glucocorticoid signaling via glucocorticoid receptors (GR) plays a critical role in alcohol use disorder (AUD). Acute alcohol withdrawal and protracted abstinence in dependent rats are associated with increased GR signaling and changes in GR-mediated transcriptional activity in the rat central nucleus of the amygdala (CeA). The GR antagonist mifepristone decreases alcohol consumption in dependent rats during acute withdrawal and protracted abstinence. Regulation of CeA synaptic activity by GR is currently unknown. Here, we utilized mifepristone and the selective GR antagonist CORT118335 (both at 10 μM) as pharmacological tools to dissect the role of GR on GABA transmission in male, adult Sprague-Dawley rats using slice electrophysiology. We subjected rats to chronic intermittent alcohol vapor exposure for 5–7 weeks to induce alcohol dependence. A subset of dependent rats subsequently underwent protracted alcohol withdrawal for 2 weeks, and air-exposed rats served as controls. Mifepristone reduced the frequency of pharmacologically-isolated spontaneous inhibitory postsynaptic currents (sIPSC) in the CeA (medial subdivision) without affecting postsynaptic measures in all groups, suggesting decreased GABA release with the largest effect in dependent rats. CORT118335 did not significantly alter GABA transmission in naïve, but decreased sIPSC frequency in dependent rats. Similarly, mifepristone decreased amplitudes of evoked inhibitory postsynaptic potentials only in dependent rats and during protracted withdrawal. Collectively, our study provides insight into regulation of CeA GABAergic synapses by GR. Chronic ethanol enhances the efficiency of mifepristone and CORT118335, thus highlighting the potential of drugs targeting GR as a promising pharmacological avenue for the treatment of AUD.

Glucocorticoid Receptor Antagonist Alters Corticosterone and Receptor-sensitive mRNAs in the Hypoxic Neonatal Rat.

Hypoxia, a common stressor with preterm birth, increases morbidity and mortality associated with prematurity. Glucocorticoids (GCs) are administered to the preterm infant to improve oxygenation; prolonged use of GCs remains controversial. We evaluated a selective glucocorticoid receptor (GR) antagonist (CORT113176) in our neonatal rat model of human prematurity to assess how fasting and hypoxia-induced increases in neonatal corticosterone affects endogenous hormones and endocrine pancreas function. Neonatal rat pups at postnatal day (PD) 2, PD8, and PD15 were pretreated with CORT113176 and, after 60 minutes of separation and fasting, exposed to hypoxia (8% O2) or control (normoxia) for 30 or 60 minutes while fasting was continued. Plasma corticosterone, ACTH, glucose, and insulin were measured and fasting Homeostatic Model Assessment of Insulin Resistance was calculated. Glucocorticoid and insulin receptor-sensitive gene mRNAs were analyzed in liver, muscle, and adipose to evaluate target tissue biomarkers. CORT113176 pretreatment augmented baseline and hypoxia-induced increases in corticosterone and attenuated hypoxia-induced increases in insulin resistance at PD2. Normoxic and hypoxic stress increased the hepatic GR-sensitive gene mRNAs, Gilz and Per1; this was eliminated by pretreatment with CORT113176. CORT113176 pretreatment decreased baseline insulin receptor-sensitive gene mRNAs Akt2, Irs1, Pik3r1, and Srebp1c at PD2. We show that CORT113176 variably augments the stress-induced increases in corticosterone concentrations (attenuation of negative feedback) and that GR is critical for hepatic responses to stress in the hypoxic neonate. We also propose that measurement of Gilz and Per1 mRNA expression may be useful to evaluate the effectiveness of GR antagonism.

Management and Medical Therapy of Mild Hypercortisolism.

Mild hypercortisolism (mHC) is defined as an excessive cortisol secretion, without the classical manifestations of clinically overt Cushing’s syndrome. This condition increases the risk of bone fragility, neuropsychological alterations, hypertension, diabetes, cardiovascular events and mortality. At variance with Cushing’s syndrome, mHC is not rare, with it estimated to be present in up to 2% of individuals older than 60 years, with higher prevalence (up to 10%) in individuals with uncontrolled hypertension and/or diabetes or with unexplainable bone fragility. Measuring cortisol after a 1 mg overnight dexamethasone suppression test is the first-line test for searching for mHC, and the degree of cortisol suppression is associated with the presence of cortisol-related consequences and mortality. Among the additional tests used for diagnosing mHC in doubtful cases, the basal morning plasma adrenocorticotroph hormone, 24-h urinary free cortisol and/or late-night salivary cortisol could be measured, particularly in patients with possible cortisol-related complications, such as hypertension and diabetes. Surgery is considered as a possible therapeutic option in patients with munilateral adrenal incidentalomas and mHC since it improves diabetes and hypertension and reduces the fracture risk. In patients with mHC and bilateral adrenal adenomas, in whom surgery would lead to persistent hypocortisolism, and in patients refusing surgery or in whom surgery is not feasible, medical therapy is needed. Currently, promising though scarce data have been provided on the possible use of pituitary-directed agents, such as the multi-ligand somatostatin analog pasireotide or the dopamine agonist cabergoline for the—nowadays—rare patients with pituitary mHC. In the more frequently adrenal mHC, encouraging data are available for metyrapone, a steroidogenesis inhibitor acting mainly against the adrenal 11-βhydroxylase, while data on osilodrostat and levoketoconazole, other new steroidogenesis inhibitors, are still needed in patients with mHC. Finally, on the basis of promising data with mifepristone, a non-selective glucocorticoid receptor antagonist, in patients with mild cortisol hypersecretion, a randomized placebo-controlled study is ongoing for assessing the efficacy and safety of relacorilant, a selective glucocorticoid receptor antagonist, for patients with mild adrenal hypercortisolism and diabetes mellitus/impaired glucose tolerance and/or uncontrolled systolic hypertension.

Ovulatory upregulation of angiotensin-converting enzyme 2, a receptor for SARS-CoV-2, in dominant follicles of the human ovary

ObjectiveTo determine the temporal expression of angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV-2, in dominant follicles throughout the periovulatory period in women and the regulatory mechanisms underlying ACE2 expression in human granulosa/lutein cells (hGLC).DesignExperimental prospective clinical study and laboratory-based investigation.SettingUniversity Medical Center and private in vitro fertilization center.Patient(s)Thirty premenopausal women undergoing surgery for tubal ligation and 16 premenopausal women undergoing in vitro fertilization.Intervention(s)Administration of human chorionic gonadotropin (hCG) and harvesting of preovulatory/ovulatory follicles by timed laparoscopy, and collection of granulosa/lutein cells and cumulus cells at the time of oocyte retrieval.Main Outcome Measure(s)Expression and localization of ACE2 in granulosa cells and dominant follicles collected throughout the periovulatory period of the menstrual cycle and in hGLC using quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry.Result(s)ACE2 expression (mRNA and protein) is up-regulated in human ovulatory follicles after administration of hCG. ACE2 expression was higher in cumulus cells than in granulosa cells. hCG increased the expression of ACE2 in primary hGLC cultures; the increase was inhibited by RU486 (an antagonist for progesterone receptor and glucocorticoid receptor) and CORT125281 (a selective glucocorticoid receptor antagonist), but not by AG1478 (an EGF receptor tyrosine kinase inhibitor) or by dexamethasone.Conclusion(s)The hormone-regulated expression of ACE2 in granulosa cells suggests a potential role of ACE2 in the ovulatory process. These data also imply the possible impact of COVID-19 on a vital cyclic event of ovarian function and thus on women's overall reproductive health. However, SAR-CoV-2 infection in ovarian cells in vivo or in vitro has yet to be determined.

Effects of the glucocorticoid receptor antagonist PT150 on stress-induced fentanyl seeking in male and female rats.

Opioid use disorder (OUD) is highly comorbid with stress-related disorders, and stress can serve as a trigger for reinstatement of drug seeking. Glucocorticoid receptor (GR) antagonists such as mifepristone (RU-486) may be effective against stress-induced drug seeking. In the current study, PT150 (formerly ORG-34517), a more selective GR antagonist, was tested using two models of stress-induced drug seeking, namely footshock and yohimbine. Adult male and female Sprague-Dawley rats were trained to self-administer fentanyl (2.5 μg/kg/infusion, i.v.) in a model of escalation. Rats then received 7 days of abstinence, followed by extinction; PT150 (0, 50 or 100 mg/kg in Nutella®; p.o.) treatment started on the first day of extinction training and continued daily until the end of the study. Following 14 days of extinction, rats were tested for reinstatement following footshock and yohimbine (0, 1, or 2 mg/kg; i.p.), tested in counterbalanced order; PT150 or placebo treatment occurred prior to each extinction and reinstatement session. Prior to initiation of PT150 treatment, females self-administered greater levels of fentanyl during 1-h sessions compared to males; however, when switched to 6-h sessions, males and females self-administered similar levels of fentanyl and showed a similar escalation of intake over time. PT150 had no effect on extinction of self-administration. While both footshock and yohimbine reinstated fentanyl seeking, only footshock-induced reinstatement was decreased by PT150 (50 and 100 mg/kg). The effect of PT150 on footshock-induced reinstatement was driven primarily by males. The glucocorticoid antagonist PT150 reduces shock-induced fentanyl seeking, suggesting it may be effective against stress-induced relapse, although the sex difference in response may need further exploration.

A randomized trial of safety and pharmacodynamic interactions between a selective glucocorticoid receptor antagonist, PT150, and ethanol in healthy volunteers

PT150, a novel competitive glucocorticoid receptor (GR) antagonist, has proven safe in animal models, healthy volunteers, and people with depression. Our study is the first to investigate PT150’s safety with alcohol use. The primary objective of this study was to evaluate pharmacodynamic interactions between ethanol and PT150 in healthy subjects. This single-site, Phase I pilot trial consisted of community-recruited, healthy, alcohol-experienced participants aged 21–64 years. Of 32 participants screened, 11 were enrolled and randomized, one of which withdrew before intervention. PT150 (900 mg/day) was administered orally to all participants for five days. All participants received two beverage challenges on Day 1 (before PT150 administration) and Day 5 (after PT150 administration). On challenge days, they received both alcohol (16% ethanol) and placebo (1% ethanol) beverages in random order. Primary outcomes included breath alcohol level, blood pressure, heart rate, adverse events, and electrocardiogram changes. There were no statistically significant differences in vital signs or estimated blood alcohol concentrations between PT150 non-exposed and exposed groups during the ethanol challenge. There were no clinically significant abnormal electrocardiograms or serious adverse events. These data show that administration of PT150 with concurrent alcohol use is safe and well-tolerated. This study supports a future pharmacokinetic interaction study between PT150 and alcohol.Trial Registration ClinicalTrials.gov Identifier: NCT03548714.

The Effect of a Novel Glucocorticoid Receptor Antagonist (CORT113176) on Glucocorticoid and Insulin Receptor Sensitive Hepatic Gene (mRNA) Expression in a Neonatal Rat Model of Human Prematurity

Preterm birth is a global health problem the sequelae of which are not well understood. Hypoxia, a common stressor with prematurity, can affect blood glucose via stress-induced increases in glucocorticoids (GC). GCs are also administered to preterm infants to improve oxygenation; however, this is controversial. CORT113176 (Corcept Therapeutics) is a novel, selective glucocorticoid receptor (GR) antagonist that does not bind to the progesterone receptor. We have demonstrated that CORT113176 (in our rat model of preterm birth) increases baseline corticosterone (due to loss of GC negative feedback) and attenuates hypoxia-induced increases in insulin resistance implicating endogenous corticosterone in post-natal metabolic adaptations to stress. We now propose that CORT113176 is useful to evaluate the hepatic effects of endogenous GCs in our rat model of preterm birth by measuring critical GC and insulin receptor sensitive gene mRNAs. Postnatal day (PD) 2 rat pups of both sexes (N=5 per treatment/sex) were pretreated with CORT113176 (600 mg/kg IP) or vehicle. After 60 minutes, a group of pups were euthanized with livers collected and preserved in RNAlater (baseline). The remaining pups were separated from their dams, exposed to normoxia (control) or hypoxia (8% O2) for 60 minutes, and livers obtained. Total hepatic RNA was extracted, and mRNA expression was analyzed (RT-qPCR) for GC and insulin receptor sensitive genes: GC: Fkbp5, Gilz, Nr3c1 (Gr), Nr3c2 (Mr), Per1, Ttpa. INSULIN: Akt2, G6Pase, Igf1r, Insr, Irs1, Irs2, Pik3cb, Pik3r1, Srebp1c. CORT113176 decreased the expression of all baseline hepatic insulin receptor mRNAs in both sexes, except for G6Pase. Pik3r1 mRNA expression significantly decreased with 60 minutes of normoxic separation (fasting) in males and females compared to baseline and hypoxic separation; this was blocked by CORT113176. In the GC receptor sensitive panel, CORT113176 decreased basal Nr3c1 (Gr) mRNA. Normoxic and hypoxic separation increased Per1 and Gilz mRNA expression; this effect was blocked by CORT113176. Interestingly, Fkbp5 expression, a proposed clinical marker for GR antagonism, was not altered by CORT113176. The hepatic GC and insulin receptor sensitive gene mRNA panels we developed are sensitive to GR antagonism suggesting they may be a useful addition to Fkbp5. The increase in endogenous corticosterone, acting via GR, is critical in the hepatic response to stress in our neonatal rat model of hypoxia and prematurity.

The development of novel glucocorticoid receptor antagonists: From rational chemical design to therapeutic efficacy in metabolic disease models

Glucocorticoids regulate numerous processes in human physiology, but deregulated or excessive glucocorticoid receptor (GR) signaling contributes to the development of various pathologies including metabolic syndrome. For this reason, GR antagonists have considerable therapeutic value. Yet, the only GR antagonist that is clinically approved to date - mifepristone - exhibits cross-reactivity with other nuclear steroid receptors like the progesterone receptor. In this study, we set out to identify novel selective GR antagonists by combining rational chemical design with an unbiased in vitro and in vivo screening approach. Using this pipeline, we were able to identify CORT125329 as the compound with the best overall profile from our octahydro series of novel GR antagonists, and demonstrated that CORT125329 does not exhibit cross-reactivity with the progesterone receptor. Further in vivo testing showed beneficial activities of CORT125329 in models for excessive corticosterone exposure and short- and long-term high-fat diet-induced metabolic complications. Upon CORT125329 treatment, most metabolic parameters that deteriorated upon high-fat diet feeding were similarly improved in male and female mice, confirming activity in both sexes. However, some sexually dimorphic effects were observed including male-specific antagonism of GR activity in brown adipose tissue and female-specific lipid lowering activities after short-term CORT125329 treatment. Remarkably, CORT125329 exhibits beneficial metabolic effects despite its lack of GR antagonism in white adipose tissue. Rather, we propose that CORT125329 treatment restores metabolic activity in brown adipose tissue by stimulating lipolysis, mitochondrial activity and thermogenic capacity. In summary, we have identified CORT125329 as a selective GR antagonist with strong beneficial activities in metabolic disease models, paving the way for further clinical investigation.

Glucocorticoid receptor modulators decrease alcohol self-administration in male rats

Alcohol use disorder (AUD) is associated with the dysregulation of brain stress and reward systems, including glucocorticoid receptors (GRs). The mixed glucocorticoid/progesterone receptor antagonist mifepristone and selective GR antagonist CORT113176 have been shown to selectively reduce alcohol consumption in alcohol-dependent rats. Mifepristone has also been shown to decrease alcohol consumption and craving for alcohol in humans with AUD. The present study tested the effects of the GR modulators CORT118335, CORT122928, CORT108297, and CORT125134 on alcohol self-administration in nondependent (air-exposed) and alcohol-dependent (alcohol vapor-exposed) adult male rats. Different GR modulators recruit different GR-associated transcriptional cofactors. Thus, we hypothesized that these GR modulators would vary in their effects on alcohol drinking. CORT118335, CORT122928, and CORT125134 significantly reduced alcohol self-administration in both alcohol-dependent and nondependent rats. CORT108297 had no effect on alcohol self-administration in either group. The present results support the potential of GR modulators for the development of treatments for AUD. Future studies that characterize genomic and nongenomic effects of these GR modulators will elucidate potential molecular mechanisms that underlie alcohol drinking in alcohol-dependent and nondependent states.

Abstract 4123: ORIC-101 overcomes glucocorticoid receptor-mediated chemoresistance in pancreatic cancer models

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and one of the most lethal cancers, with a 5-year survival rate of 8%. Chemotherapy remains the main treatment option for patients with advanced and metastatic tumors. However, intrinsic resistance to chemotherapeutics and lack of effective targeted therapies are major factors contributing to the dismal prognosis. Activation of glucocorticoid receptor (GR) signaling confers resistance to chemotherapy in solid tumors, making GR antagonism an attractive combination treatment strategy to overcome chemotherapeutic resistance. ORIC-101 is a novel selective GR antagonist under clinical evaluation in combination with anticancer therapies. We previously reported that ORIC-101 can sensitize triple-negative breast cancer cells to chemotherapy by reversing multiple GR-modulated pathways. Here, we investigate the effects of ORIC-101 in preclinical models of PDAC. Employing in vitro functional assays and gene expression analysis, ORIC-101 exhibited chemo-potentiation in a panel of PDAC cell lines. Biomarker analysis of transcription activity following ORIC-101 treatment in vitro confirmed pharmacodynamic (PD) modulation of core GR target genes, indicative of suppressed GR signaling. Extending these findings in vivo across several PDAC xenograft models (SW1990, BxPC3, and HPAC) revealed that ORIC-101 blocks GR transcriptional activity induced by dexamethasone in a dose-dependent manner. The PD modulation observed in vivo correlated with ORIC-101 plasma exposure. Consistent with ORIC-101's ability to suppress GR activity, in vivo efficacy studies in combination with paclitaxel significantly inhibited PDAC tumor growth compared to the paclitaxel control group. These results in PDAC preclinical models support the clinical development of ORIC-101 in overcoming GR-driven chemoresistance. A phase 1b study of ORIC-101 in combination with nab-paclitaxel in patients with advanced or metastatic solid tumors is ongoing (NCT03928314). Citation Format: Jessica D. Sun, Haiying Zhou, Wayne Kong, Natalie Yuen, Frank L. Duong, Shravani Barkund, Aleksandr Pankov, Dan McWeeney, Qiuping Ye, Omar Kabbarah, Lori S. Friedman, Anneleen Daemen, Melissa Junttila. ORIC-101 overcomes glucocorticoid receptor-mediated chemoresistance in pancreatic cancer models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4123.

Impact of relacorilant, a selective glucocorticoid receptor antagonist, on the immunosuppressive effects of endogenous cortisol.

3091 Background: Cortisol, an endogenous glucocorticoid receptor (GR) agonist, controls a broad transcriptional program that affects T-cell activation, pro-inflammatory cytokine secretion, and immune cell trafficking. By selectively antagonizing GR, relacorilant may reverse the immunosuppressive effects of cortisol in solid tumor cancers. Methods: Immune cells and GR expression were assessed by IHC and calculated based on The Cancer Genome Atlas (TCGA) data. Human PBMCs were stimulated with αCD3+IL-12 +/- cortisol or cortisol + relacorilant. EG7 tumor-bearing mice were treated with anti-PD1 (RMP1-14) ip Q5D +/- relacorilant QD. Whole blood mRNA was measured via Nanostring, hematology was performed using standard complete blood count assays, and cytokines were assessed by immunoassays in study NCT02762981. Results: GR expression was observed in human tumor and immune cells. Its abundance was positively correlated with tumor infiltration of TH2, Treg, and PDL1+ cells ( P&lt; .001) and negatively correlated with TH1 cells ( P&lt; .001). In PBMCs, cortisol inhibited, and relacorilant restored, CD8+ T-cell activation ( P&lt; .001) and pro-inflammatory cytokine secretion (TNFα P= .006, IFNγ P&lt; .05). In the EG7 syngeneic model, relacorilant increased αPD1 efficacy ( P= .007) and decreased circulating IL-10 ( P&lt; .002). In patients with advanced solid tumors, relacorilant + nab-paclitaxel systemically suppressed the expression of canonical GR-controlled genes ( ptgs2 P&lt; .001) and genes encoding candidate-immunomodulatory drug targets ( cxcl8, ptger4, ido1; P&lt; .001). In a small subset of patients (n = 11), sustained clinical response was associated with increased T-cell count ( P= .06) and IFNγ ( P= .03), as well as decreased Tregs ( P= .06) and IL-10 ( P= .03). Conclusions: Evidence of T-cell activation by relacorilant was observed in PBMCs, syngeneic mouse tumors, and patients with sustained response in a Phase 1 study. This supports the hypothesis that relacorilant can reverse immune suppression by endogenous cortisol in solid tumor cancers. Clinical studies with immune checkpoint inhibitors and relacorilant are planned.

SUN-214 A Novel Glucocorticoid Receptor Antagonist (CORT113176) Reveals Unique Developmental and Tissue-Specific Effects in a Neonatal Rat Model of Human Prematurity

Premature birth is a major public health problem worldwide and can lead to transient adrenal insufficiency1,2. The stress of premature birth includes the inability to control blood glucose and maintain normal oxygenation leading to hypoxia3. Corticosteroid administration enhances surfactant production and improves oxygenation in preterm humans. However, corticosteroids can also have negative consequences4,5. We have validated a rat model of separation and hypoxia on post-natal day (PD) 2 that emulates the stress and treatment of hypoxia in the preterm human infant6,7. We hypothesized that the role of endogenous glucocorticoids in our neonatal rat model of preterm birth can be evaluated using the novel selective glucocorticoid receptor (GR) antagonist CORT113176 (Corcept) which is devoid of progesterone receptor effects8. Pups (PD 2, 8, or 15; N=6–8 per treatment/timepoint) were given CORT113176 (60 mg/kg IP) or vehicle, then placed into chambers in room air with mild warming to prevent hypothermia due to maternal separation. 60 min later, one group of pups was euthanized and trunk blood collected (baseline). The remaining pups were exposed to hypoxia (8% O2) or normoxia (time control) for 30 or 60 min at which times trunk blood was collected for the measurement of plasma glucose, insulin, ACTH, and corticosterone. Plasma ACTH, corticosterone, and insulin were measured by immunoassay. Glucose was measured by glucose oxidase method and insulin sensitivity calculated (HOMA-IR). Organs were frozen (brain, pituitary, adrenal glands, kidney, liver, muscle, fat) for future assessment of tissue-specific glucocorticoid-sensitive gene expression. In PD2 rats, basal and hypoxia-stimulated plasma ACTH and corticosterone were lower and basal HOMA-IR greater with CORT113176 pretreatment suggesting (unexpectedly) glucocorticoid agonist activity. In PD8 and PD15 rats, basal and hypoxia-stimulated plasma ACTH and corticosterone were augmented after CORT113176 pretreatment demonstrating classic antagonist activity. However, in PD8 rats, CORT113176 effects were tissue-specific acting as a classic antagonist on the HPA-axis, but as an agonist on whole-body insulin resistance. The differential effects of CORT113176 based on age and target tissue indicate that GR regulation changes in early development in our animal model of human prematurity. These findings may have significant implications in the treatment of hypoxia and transient adrenal insufficiency in the preterm infant1,2 as well as give insight into the nuances of the control of glucocorticoid receptor function. 1Lancet 392:1923–1994, 2018 2Curr Opin Endocrinol Diabetes Obes 17:8–12, 2010 3Compr Ther 13:14–19, 1987 4Int Immunopharmacol 66:242–250, 2019 5J Neuroendocrinol 27:468–480, 2015 6Am J Physiol 300:R708-715, 2011 7Am J Physiol 302:R627-R633, 2012 8Med Chem Lett 25:5720−5725, 2015

MON-163 A Phase 3, Double-Blind, Randomized, Placebo-Controlled Study to Assess the Efficacy and Safety of a Selective Glucocorticoid Receptor Modulator, Relacorilant, in Patients with Autonomous Cortisol Secretion Due to Cortisol-Secreting Adrenal Adenoma(s)/Hyperplasia

Relacorilant is a highly selective glucocorticoid receptor antagonist that modulates the effects of excess cortisol without interacting with the mineralocorticoid or progesterone receptor. A Phase 2 relacorilant study in patients with endogenous Cushing syndrome (CS) demonstrated improvements in glycemic control and hypertension with no instances of drug-related hypokalemia or antiprogesterone effects.An international, multicenter, Phase 3 clinical trial of relacorilant is currently underway to evaluate the efficacy and safety of relacorilant in CS of various etiologies with evidence of hypercortisolism documented through two independent biochemical tests and at least two clinical signs and symptoms of CS. It uses a randomized-withdrawal design after 22-weeks (22wk) of open-label treatment with relacorilant (GRACE Study: NCT03697109).Here we introduce a double-blind, randomized, placebo-controlled study in patients with less severe CS secondary to adrenal adenoma(s) or hyperplasia. Approximately 130 eligible patients 18-80 years old with a radiologically confirmed adrenal lesion, a biochemical diagnosis of autonomous cortisol secretion and either impaired glucose tolerance/diabetes mellitus (IGT/DM) or hypertension will receive relacorilant (100 mg/day, titrated to 400 mg/day, as tolerated) or placebo over 22WK.Biochemical criteria for entry into the study include a serum cortisol >1.8 µg/dL after dexamethasone suppression testing (DST) and low (<10 pg/dL) or suppressed morning ACTH levels. Patients must be stable on their antidiabetic and/or antihypertensive agents for at least 4 weeks prior to the first dose of relacorilant.The primary efficacy endpoints are the between-treatment difference in change from Baseline to 22wk in AUCglucose for the IGT/DM group and mean systolic blood pressure (based on ambulatory blood pressure monitoring) for the hypertension group. Secondary endpoints include changes in weight, waist circumference, quality of life and coagulation markers. The safety analysis will be performed for all patients who received at least one dose of study drug.This will be the first randomized, double-blind, placebo-controlled study to test if patients with adrenal autonomous hypercortisolism benefit from medical treatment.

The selective glucocorticoid receptor antagonist CORT125281 has tissue-specific activity.

Glucocorticoids mediate numerous essential processes in the human body via binding to the glucocorticoid receptor (GR). Excessive GR signaling can cause disease, and GR antagonists can be used to treat many symptoms of glucocorticoid-induced pathology. The purpose of this study was to characterize the tissue-specific properties of the selective GR antagonist CORT125281. We evaluated the antagonistic effects of CORT125281 upon acute and subchronic corticosterone exposure in mice. In the acute corticosterone setting, hypothalamus-pituitary-adrenal-axis activity was investigated by measurement of basal- and stress-induced corticosterone levels, adrenocorticotropic hormone levels and pituitary proopiomelanocortin expression. GR signaling was evaluated by RT-PCR analysis of GR-responsive transcripts in liver, muscle, brown adipose tissue (BAT), white adipose tissue (WAT) and hippocampus. Pretreatment with a high dose of CORT125281 antagonized GR activity in a tissue-dependent manner. We observed complete inhibition of GR-induced target gene expression in the liver, partial blockade in muscle and BAT and no antagonism in WAT and hippocampus. Tissue distribution only partially explained the lack of effective antagonism. CORT125281 treatment did not disinhibit the hypothalamus-pituitary-adrenal neuroendocrine axis. In the subchronic corticosterone setting, CORT125281 partially prevented corticosterone-induced hyperinsulinemia, but not hyperlipidemia and immune suppression. In conclusion, CORT125281 antagonizes GR transcriptional activity in a tissue-dependent manner and improves corticosterone-induced hyperinsulinemia. Tailored dosing of CORT125281 may allow tissue-specific inhibition of GR transcriptional activity.