11β-HSD1 inhibition in men mitigates prednisolone-induced adverse effects in a proof-of-concept randomised double-blind placebo-controlled trial

Steroid hormones as modulators of anti-tumoural immunity

Immune evasion is a hallmark of cancer progression but the role of steroid hormones in this evasion has long been underrated. This oversight is particularly notable for glucocorticoids given that exogenous glucocorticoids remain a cornerstone therapy in various oncological treatment regimens, supportive care and treatment of immune-related adverse events caused by immune-checkpoint inhibitors. Cortisol, the main endogenous glucocorticoid in humans, is secreted by the adrenal cortex in response to stress. Additionally, cortisol and its inactive metabolite cortisone can be interconverted to further modulate tissue-dependent glucocorticoid action. In the past 5 years, intratumoural production of glucocorticoids, by both immune and tumour cells, has been shown to support tumour immune evasion. Here, we summarize current progress at the crossroads of endocrinology and immuno-oncology. We outline the known effects of steroid hormones on different immune cell types with a focus on glucocorticoids and androgens. We conclude with options for pharmaceutical intervention, including the engineering of cell-based therapies that resist the immunosuppressive action of steroid hormones. Overall, local steroid production and metabolism are emerging elements of tumour immune suppression that are potentially amenable to therapeutic intervention. Targeting steroid hormones to enhance anticancer therapies could increase their efficacy but will require expertise in endocrine care.

Neuromuscular sarcopenia: what do we know?

PURPOSE OF REVIEW

Sarcopenia is a common and relevant health problem in the treatment of geriatric patients. After many years of dealing with the definition of this phenomenon, the focus in the future must be on underlying and treatable pathomechanisms.

RECENT FINDINGS

The article describes the initial state with regard to the definition of sarcopenia and derives from this the focus on subgroups of sarcopenia with treatable pathomechanisms. One subgroup of neuromuscular sarcopenia, which focuses on the degeneration of the neuromuscular junction, is discussed. In this context, the proteoglycan agrin with its ability to cluster acetylcholine receptors in the postsynaptic membrane of the muscle plays a role. Inactivation of agrin leads to destabilization of the neuromuscular junction and thus to sarcopenia. The resulting neuronal 22 kDa C-terminal agrin fragment should serve as a biomarker of neuromuscular sarcopenia.

SUMMARY

The neuronal C-terminal agrin fragment must be established as a biomarker for neuromuscular sarcopenia, taking renal function into account as the fragment accumulates in renal insufficient patients. On this basis, treatment with agrin could be a therapeutic option for this subgroup of sarcopenia.

Vamorolone: a novel metabolism resistant steroid that suppresses joint destruction in chronic polyarthritis with reduced systemic side effects

OBJECTIVES

Vamorolone, a dissociated steroidal compound with reduced side effects, offers a promising alternative to traditional glucocorticoids for inflammatory diseases. Unlike conventional glucocorticoids, vamorolone lacks the hydroxyl or ketone groups required for metabolism by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a key enzyme that modulates glucocorticoid activity. This study investigates vamorolone's resistance to 11β-HSD1 metabolism and assesses its therapeutic efficacy in the murine tumour necros factor-alpha-overexpressing (TNFtg) model of polyarthritis.

METHODS

11β-HSD1 metabolism and action were examined in Hs68 and primary leucocyte culture. Vamorolone 20 mg/kg/day, prednisolone (standard of care) or vehicle were administered by gavage to TNFtg or TNFtg 11β-HSD1 knock-out (TNFtg11BKOKO) animals. Body weight and disease severity were scored daily, and markers of inflammation, joint destruction and side effects assessed at day 56 of age.

RESULTS

Vamorolone was entirely resistant to 11β-HSD1 metabolism in vitro. Vamorolone demonstrated comparable anti-inflammatory actions in TNFtg mice, with a comparable reduction in joint inflammation, serum interleukin-6 (IL-6) and synovitis relative to prednisolone. However, vamorolone-treated mice did not experience typical glucocorticoid side effects, including adrenal atrophy, body weight reduction, muscle wasting or inhibition of anabolic bone metabolism. These benefits persisted in 11β-HSD1 knockout mice, indicating that the efficacy of vamorolone is largely independent of 11β-HSD1 metabolism.

CONCLUSION

The findings suggest that at the effective anti-inflammatory dose examined in this study, vamorolone possesses a reduced profile of deleterious systemic effects relative to prednisolone. Whilst highlighting its potential for broader clinical application in inflammatory conditions, it remains unclear whether these side effects would remain mild at markedly higher doses.

Adrenal Suppression From Vamorolone and Prednisone in Duchenne Muscular Dystrophy: Results From the Phase 2b Clinical Trial

CONTEXT

Vamorolone, a novel "dissociative" steroid, demonstrated similar efficacy in muscle function relative to prednisone 0.75 mg/kg/day but improved linear growth and bone turnover markers in a randomized trial of pediatric Duchenne muscular dystrophy (DMD).

OBJECTIVES

To determine the frequency of adrenal suppression (AS) induced by vamorolone and prednisone in pediatric DMD and to assess cortisol thresholds using a monoclonal antibody immunoassay.

METHODS

Post hoc analysis of cortisol levels was performed on data from a randomized, double-blind, placebo- and prednisone-controlled 24-week trial of vamorolone with a 24-week crossover extension. Morning and ACTH-stimulated cortisol levels were measured using the Elecsys II immunoassay, with AS defined as a stimulated cortisol of <500 nmol/L ("historical threshold") and <400 nmol/L ("revised threshold").

RESULTS

Mean age at enrolment was 5.41 ± 0.86 years (n = 118). At week 24, the proportion of participants with AS using the historical and revised cortisol thresholds, respectively, were as follows: prednisone 0.75 mg/kg/day = 100% (25/25) and 92.0% (23/25); vamorolone 6 mg/kg/day = 95.2% (20/21) and 90.5% (19/21); vamorolone 2 mg/kg/day = 84.2% (16/19) and 47.5% (9/19); and placebo = 20.0% (4/20) and 0% (0/20). Morning and peak ACTH-stimulated cortisol were strongly correlated in steroid-treated boys (Spearman correlation week 48 = 0.83).

CONCLUSION

AS after vamorolone and prednisone was frequent and vamorolone-associated AS appeared dose-dependent. A lower stimulated cortisol threshold may be appropriate when using a monoclonal assay. We recommend hydrocortisone for glucocorticoid stress dosing in patients receiving vamorolone.

New Approaches to the Treatment of Hypercortisolism

This review explores the evolving landscape of treatments for hypercortisolism, highlighting both established and emerging therapies. Although surgery remains the cornerstone of management, medical therapies play a crucial and expanding role, especially in cases of persistent, recurrent, or severe hypercortisolism. We discuss the effectiveness and limitations of steroidogenesis inhibitors, pituitary-directed drugs, glucocorticoid receptor antagonists, and experimental drugs targeting novel molecular pathways that have been implicated in the pathogenesis of hypercortisolism. Despite advancements, significant unmet needs persist, underscoring the importance of personalized treatment approaches and the development of targeted therapies. Ongoing and future clinical trials are crucial for validating the safety and efficacy of these innovative treatments in Cushing disease management.

Current Challenges and Future Directions in the Assessment of Glucocorticoid Status

Glucocorticoid (GC) hormones are secreted in a circadian and ultradian rhythm and play a critical role in maintaining physiological homeostasis, with both excess and insufficient GC associated with adverse effects on health. Current assessment of GC status is primarily clinical, often in conjunction with serum cortisol values, which may be stimulated or suppressed depending on the GC disturbance being assessed. In the setting of extreme perturbations in cortisol levels ie, markedly low or high levels, symptoms and signs of GC dysfunction may be overt. However, when disturbances in cortisol GC status values are less extreme, such as when assessing optimization of a GC replacement regimen, signs and symptoms can be more subtle or nonspecific. Current tools for assessing GC status are best suited to identifying profound disturbances but may lack sensitivity for confirming optimal GC status. Moreover, single cortisol values do not necessarily reflect an individual's GC status, as they are subject to inter- and intraindividual variation and do not take into account the pulsatile nature of cortisol secretion, variation in binding proteins, or local tissue concentrations as dictated by 11beta-hydroxysteroid dehydrogenase activity, as well as GC receptor sensitivity. In the present review, we evaluate possible alternative methods for the assessment of GC status that do not solely rely on the measurement of circulating cortisol levels. We discuss the potential of changes in metabolomic profiles, micro RNA, gene expression, and epigenetic and other novel biomarkers such as growth differentiating factor 15 and osteocalcin, which could in the future aid in the objective classification of GC status.

Targeting osteoblastic 11β-HSD1 to combat high-fat diet-induced bone loss and obesity

Excessive glucocorticoid (GC) action is linked to various metabolic disorders. Recent findings suggest that disrupting skeletal GC signaling prevents bone loss and alleviates metabolic disorders in high-fat diet (HFD)-fed obese mice, underpinning the neglected contribution of skeletal GC action to obesity and related bone loss. Here, we show that the elevated expression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), the enzyme driving local GC activation, and GC signaling in osteoblasts, are associated with bone loss and obesity in HFD-fed male mice. Osteoblast-specific 11β-HSD1 knockout male mice exhibit resistance to HFD-induced bone loss and metabolic disorders. Mechanistically, elevated 11β-HSD1 restrains glucose uptake and osteogenic activity in osteoblast. Pharmacologically inhibiting osteoblastic 11β-HSD1 by using bone-targeted 11β-HSD1 inhibitor markedly promotes bone formation, ameliorates glucose handling and mitigated obesity in HFD-fed male mice. Taken together, our study demonstrates that osteoblastic 11β-HSD1 directly contributes to HFD-induced bone loss, glucose handling impairment and obesity.

Long-term health consequences of congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency accounts for 95% of all CAH cases and is one of the most common inborn metabolic conditions. The introduction of life-saving glucocorticoid replacement therapy 70 years ago has changed the perception of CAH from a paediatric disorder into a lifelong, chronic condition affecting patients of all age groups. Alongside health problems that can develop during the time of paediatric care, there is an emerging body of evidence suggesting an increased risk of developing co-morbidities during adult life in patients with CAH. The mechanisms that drive the negative long-term outcomes associated with CAH are complex and involve supraphysiological replacement therapies (glucocorticoids and mineralocorticoids), excess adrenal androgens both in the intrauterine and postnatal life, elevated steroid precursors and adrenocorticotropic hormone levels. Alongside a review of mortality outcome, we discuss issues that need to be addressed when caring for the CAH patient including female and male fertility, cardio-metabolic morbidity, bone health and other important long-term outcomes of CAH.

Impaired 11β-HSD1 Activity in a Male Patient With Cushing Disease Resulting in Lack of the Full Cushingoid Phenotype

We present a patient who had surgically confirmed CD but without the full cushingoid phenotype despite markedly elevated cortisol. Nonpathologic causes of elevated ACTH and cortisol were eliminated as were pathogenic variants in the glucocorticoid receptor gene. Further studies of urine metabolites, cortisol half-life, and the ratios of cortisone to cortisol conversion revealed impaired 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. There have only been 2 prior reports of impaired 11β-HSD1 resulting in lack of classic cushingoid features in the past 2 decades. Our patient's presentation and previous reports demonstrate the key role of 11β-HSD1 in modulating intracellular cortisol concentration, therefore shielding the peripheral tissues from the effects of excess cortisol. When patients present with markedly elevated cortisol but without classic cushingoid features, impaired 11β-HSD1 should be considered in the differential diagnosis.

Myricanol improves metabolic profiles in dexamethasone induced lipid and protein metabolism disorders in mice

Myricanol (MY) is one of the main active components from bark of Myrica Rubra. It is demonstrated that MY rescues dexamethasone (DEX)-induced muscle dysfunction via activating silent information regulator 1 (SIRT1) and increasing adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation. Since SIRT1 and AMPK are widely involved in the metabolism of nutrients, we speculated that MY may exert beneficial effects on DEX-induced metabolic disorders. This study for the first time applied widely targeted metabolomics to investigate the beneficial effects of MY on glucose, lipids, and protein metabolism in DEX-induced metabolic abnormality in mice. The results showed that MY significantly reversed DEX-induced soleus and gastrocnemius muscle weight loss, muscle fiber damage, and muscle strength loss. MY alleviated DEX-induced metabolic disorders by increasing SIRT1 and glucose transporter type 4 (GLUT4) expressions. Additionally, myricanol prevented muscle cell apoptosis and atrophy by inhibiting caspase 3 cleavages and muscle ring-finger protein-1 (MuRF1) expression. Metabolomics showed that MY treatment reversed the serum content of carnitine ph-C1, palmitoleic acid, PS (16:0_17:0), PC (14:0_20:5), PE (P-18:1_16:1), Cer (t18:2/38:1(2OH)), four amino acids and their metabolites, and 16 glycerolipids in DEX mice. Kyoto encyclopedia of genes and genomes (KEGG) and metabolic set enrichment analysis (MSEA) analysis revealed that MY mainly affected metabolic pathways, glycerolipid metabolism, lipolysis, fat digestion and absorption, lipid and atherosclerosis, and cholesterol metabolism pathways through regulation of metabolites involved in glutathione, butanoate, vitamin B6, glycine, serine and threonine, arachidonic acid, and riboflavin metabolism. Collectively, MY can be used as an attractive therapeutic agent for DEX-induced metabolic abnormalities.

Iatrogenic adrenal insufficiency in adults

Iatrogenic adrenal insufficiency (IAI) is the most common form of adrenal insufficiency in adult patients, although its overall exact prevalence remains unclear. IAI is associated with adverse clinical outcomes, including adrenal crisis, impaired quality of life and increased mortality; therefore, it is imperative that clinicians maintain a high index of suspicion in patients at risk of IAI to facilitate timely diagnosis and appropriate management. Herein, we review the major causes, clinical consequences, diagnosis and care of patients with IAI. The management of IAI, particularly glucocorticoid-induced (or tertiary) adrenal insufficiency, can be particularly challenging, and the provision of adequate glucocorticoid replacement must be balanced against minimizing the cardiometabolic effects of excess glucocorticoid exposure and optimizing recovery of the hypothalamic-pituitary-adrenal axis. We review current treatment strategies and their limitations and discuss developments in optimizing treatment of IAI. This comprehensive Review aims to aid clinicians in identifying who is at risk of IAI, how to approach screening of at-risk populations and how to treat patients with IAI, with a focus on emergency management and prevention of an adrenal crisis.

Identification of a human blood biomarker of pharmacological 11β-hydroxysteroid dehydrogenase 1 inhibition

BACKGROUND AND PURPOSE

11β-Hydroxysteroid dehydrogenase-1 (11β-HSD1) catalyses the oxoreduction of cortisone to cortisol, amplifying levels of active glucocorticoids. It is a pharmaceutical target in metabolic disease and cognitive impairments. 11β-HSD1 also converts some 7oxo-steroids to their 7β-hydroxy forms. A recent study in mice described the ratio of tauroursodeoxycholic acid (TUDCA)/tauro-7oxolithocholic acid (T7oxoLCA) as a biomarker for decreased 11β-HSD1 activity. The present study evaluates the equivalent bile acid ratio of glycoursodeoxycholic acid (GUDCA)/glyco-7oxolithocholic acid (G7oxoLCA) as a biomarker for pharmacological 11β-HSD1 inhibition in humans and compares it with the currently applied urinary (5α-tetrahydrocortisol + tetrahydrocortisol)/tetrahydrocortisone ((5αTHF + THF)/THE) ratio.

EXPERIMENTAL APPROACH

Bile acid profiles were analysed by ultra-HPLC tandem-MS in blood samples from two independent, double-blind placebo-controlled clinical studies of the orally administered selective 11β-HSD1 inhibitor AZD4017. The blood GUDCA/G7oxoLCA ratio was compared with the urinary tetrahydro-glucocorticoid ratio for ability to detect 11β-HSD1 inhibition.

KEY RESULTS

No significant alterations were observed in bile acid profiles following 11β-HSD1 inhibition by AZD4017, except for an increase of the secondary bile acid G7oxoLCA. The enzyme product/substrate ratio GUDCA/G7oxoLCA was found to be more reliable to detect 11β-HSD1 inhibition than the absolute G7oxoLCA concentration in both cohorts. Comparison of the blood GUDCA/G7oxoLCA ratio with the urinary (5αTHF + THF)/THE ratio revealed that both successfully detect 11β-HSD1 inhibition.

CONCLUSIONS AND IMPLICATIONS

11β-HSD1 inhibition does not cause major alterations in bile acid homeostasis. The GUDCA/G7oxoLCA ratio represents the first blood biomarker of pharmacological 11β-HSD1 inhibition and may replace or complement the urinary (5αTHF + THF)/THE ratio biomarker.

Steroid responsiveness in alcohol-associated hepatitis is linked to glucocorticoid metabolism, mitochondrial repair, and heat shock proteins

BACKGROUND

Alcohol-associated hepatitis (AH) is one of the clinical presentations of alcohol-associated liver disease. AH has poor prognosis, and corticosteroids remain the mainstay of drug therapy. However, ~40% of patients do not respond to this treatment, and the mechanisms underlying the altered response to corticosteroids are not understood. The current study aimed to identify changes in hepatic protein expression associated with responsiveness to corticosteroids and prognosis in patients with AH.

METHODS

Patients with AH were enrolled based on the National Institute on Alcohol Abuse and Alcoholism inclusion criteria for acute AH and further confirmed by a diagnostic liver biopsy. Proteomic analysis was conducted on liver samples acquired from patients with AH grouped as nonresponders (AH-NR, n = 7) and responders (AH-R, n = 14) to corticosteroids, and nonalcohol-associated liver disease controls (n = 10). The definition of responders was based on the clinical prognostic model, the Lille Score, where a score < 0.45 classified patients as AH-R and a score > 0.45 as AH-NR. Primary outcomes used to assess steroid response were Lille Score (eg, improved liver function) and survival at 24 weeks.

RESULTS

Reduced levels of the glucocorticoid receptor and its transcriptional co-activator, glucocorticoid modulatory element-binding protein 2, were observed in the hepatic proteome of AH-NR versus AH-R. The corticosteroid metabolizing enzyme, 11-beta-hydroxysteroid dehydrogenase 1, was increased in AH-NR versus AH-R along with elevated mitochondrial DNA repair enzymes, while several proteins of the heat shock pathway were reduced. Analysis of differentially expressed proteins in AH-NR who survived 24 weeks relative to AH-NR nonsurvivors revealed several protein expression changes, including increased levels of acute phase proteins, elevated coagulation factors, and reduced mast cell markers.

CONCLUSIONS

This study identified hepatic proteomic changes that may predict responsiveness to corticosteroids and mortality in patients with AH.

11β-Hydroxysteroid dehydrogenase and the brain: Not (yet) lost in translation

11-beta-hydroxysteroid dehydrogenases (11β-HSDs) catalyse the conversion of active 11-hydroxy glucocorticoids (cortisol, corticosterone) and their inert 11-keto forms (cortisone, 11-dehydrocorticosterone). They were first reported in the body and brain 70 years ago, but only recently have they become of interest. 11β-HSD2 is a dehydrogenase, potently inactivating glucocorticoids. In the kidney, 11β-HSD2 generates the aldosterone-specificity of intrinsically non-selective mineralocorticoid receptors. 11β-HSD2 also protects the developing foetal brain and body from premature glucocorticoid exposure, which otherwise engenders the programming of neuropsychiatric and cardio-metabolic disease risks. In the adult CNS, 11β-HSD2 is confined to a part of the brain stem where it generates aldosterone-specific central control of salt appetite and perhaps blood pressure. 11β-HSD1 is a reductase, amplifying active glucocorticoid levels within brain cells, notably in the cortex, hippocampus and amygdala, paralleling its metabolic functions in peripheral tissues. 11β-HSD1 is elevated in the ageing rodent and, less certainly, human forebrain. Transgenic models show this rise contributes to age-related cognitive decline, at least in mice. 11β-HSD1 inhibition robustly improves memory in healthy and pathological ageing rodent models and is showing initial promising results in phase II studies of healthy elderly people. Larger trials are needed to confirm and clarify the magnitude of effect and define target populations. The next decade will be crucial in determining how this tale ends - in new treatments or disappointment.

Treating the Side Effects of Exogenous Glucocorticoids; Can We Separate the Good From the Bad?

It is estimated that 2% to 3% of the population are currently prescribed systemic or topical glucocorticoid treatment. The potent anti-inflammatory action of glucocorticoids to deliver therapeutic benefit is not in doubt. However, the side effects associated with their use, including central weight gain, hypertension, insulin resistance, type 2 diabetes (T2D), and osteoporosis, often collectively termed iatrogenic Cushing's syndrome, are associated with a significant health and economic burden. The precise cellular mechanisms underpinning the differential action of glucocorticoids to drive the desirable and undesirable effects are still not completely understood. Faced with the unmet clinical need to limit glucocorticoid-induced adverse effects alongside ensuring the preservation of anti-inflammatory actions, several strategies have been pursued. The coprescription of existing licensed drugs to treat incident adverse effects can be effective, but data examining the prevention of adverse effects are limited. Novel selective glucocorticoid receptor agonists and selective glucocorticoid receptor modulators have been designed that aim to specifically and selectively activate anti-inflammatory responses based upon their interaction with the glucocorticoid receptor. Several of these compounds are currently in clinical trials to evaluate their efficacy. More recently, strategies exploiting tissue-specific glucocorticoid metabolism through the isoforms of 11β-hydroxysteroid dehydrogenase has shown early potential, although data from clinical trials are limited. The aim of any treatment is to maximize benefit while minimizing risk, and within this review we define the adverse effect profile associated with glucocorticoid use and evaluate current and developing strategies that aim to limit side effects but preserve desirable therapeutic efficacy.

Glucocorticoids and cognitive function: a walkthrough in endogenous and exogenous alterations

PURPOSE

The hypothalamic-pituitary-adrenal (HPA) axis exerts many actions on the central nervous system (CNS) aside from stress regulation. Glucocorticoids (GCs) play an important role in affecting several cognitive functions through the effects on both glucocorticoid (GR) and mineralocorticoid receptors (MR). In this review, we aim to unravel the spectrum of cognitive dysfunction secondary to derangement of circulating levels of endogenous and exogenous glucocorticoids.

METHODS

All relevant human prospective and retrospective studies published up to 2022 in PubMed reporting information on HPA disorders, GCs, and cognition were included.

RESULTS

Cognitive impairment is commonly found in GC-related disorders. The main brain areas affected are the hippocampus and pre-frontal cortex, with memory being the most affected domain. Disease duration, circadian rhythm disruption, circulating GCs levels, and unbalanced MR/GR activation are all risk factors for cognitive decline in these patients, albeit with conflicting data among different conditions. Lack of normalization of cognitive dysfunction after treatment is potentially attributable to GC-dependent structural brain alterations, which can persist even after long-term remission.

CONCLUSION

The recognition of cognitive deficits in patients with GC-related disorders is challenging, often delayed, or mistaken. Prompt recognition and treatment of underlying disease may be important to avoid a long-lasting impact on GC-sensitive areas of the brain. However, the resolution of hormonal imbalance is not always followed by complete recovery, suggesting irreversible adverse effects on the CNS, for which there are no specific treatments. Further studies are needed to find the mechanisms involved, which may eventually be targeted for treatment strategies.

Tumors produce glucocorticoids by metabolite recycling, not synthesis, and activate Tregs to promote growth

Glucocorticoids are steroid hormones with potent immunosuppressive properties. Their primary source is the adrenals, where they are generated via de novo synthesis from cholesterol. In addition, many tissues have a recycling pathway in which glucocorticoids are regenerated from inactive metabolites by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1, encoded by Hsd11b1). Here, we find that multiple tumor types express Hsd11b1 and produce active glucocorticoids. Genetic ablation of Hsd11b1 in such cells had no effect on in vitro growth, but reduced in vivo tumor progression, which corresponded with increased frequencies of CD8+ tumor-infiltrating lymphocytes (TILs) expressing activation markers and producing effector cytokines. Tumor-derived glucocorticoids were found to promote signatures of Treg activation and suppress signatures of conventional T cell activation in tumor-infiltrating Tregs. Indeed, CD8+ T cell activation was restored and tumor growth reduced in mice with Treg-specific glucocorticoid receptor deficiency. Importantly, pharmacologic inhibition of 11β-HSD1 reduced tumor growth to the same degree as gene knockout and rendered immunotherapy-resistant tumors susceptible to PD-1 blockade. Given that HSD11B1 expression is upregulated in many human tumors and that inhibition of 11β-HSD1 is well tolerated in clinical studies, these data suggest that targeting 11β-HSD1 may be a beneficial adjunct in cancer therapy.

In vitro methods to assess 11β-hydroxysteroid dehydrogenase type 1 activity

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive 11-keto-glucocorticoids to their active 11β-hydroxylated forms. It also catalyzes the oxoreduction of other endogenous and exogenous substrates. The ubiquitously expressed 11β-HSD1 shows high levels in liver and other metabolically active tissues such as brain and adipose tissue. Pharmacological inhibition of 11β-HSD1 was found to ameliorate adverse metabolic effects of elevated glucocorticoids in rodents and humans, improve wound healing and delay skin aging, and enhance memory and cognition in rodent Alzheimer's disease models. Thus, there is an interest to develop 11β-HSD1 inhibitors for therapeutic purposes. This chapter describes in vitro methods to assess 11β-HSD1 enzyme activity for different purposes, be it in disease models, for the assessment of the kinetics of novel substrates or for the screening and characterization of inhibitors. 11β-HSD1 protein expression and preparations of the different biological samples are discussed first, followed by a description of a well-established and easily adaptable 11β-HSD1 enzyme activity assay. Finally, different readout methods are shortly described. This chapter should provide the reader with a toolbox of methods to assess 11β-HSD1 activity with instructions in the form of a decision tree for the choice and implementation of an appropriate enzyme activity assay.