Glucocorticoid receptor regulates accurate chromosome segregation and is associated with malignancy

Daily glucocorticoids promote glioblastoma growth and circadian synchrony to the host

Glioblastoma (GBM) is the most common primary brain tumor in adults with a poor prognosis despite aggressive therapy. A recent, retrospective clinical study found that administering Temozolomide in the morning increased patient overall survival by 6 months compared to evening. Here, we tested the hypothesis that daily host signaling regulates tumor growth and synchronizes circadian rhythms in GBM. We found daily Dexamethasone promoted or suppressed GBM growth depending on time of day of administration and on the clock gene, Bmal1. Blocking circadian signals, like VIP or glucocorticoids, dramatically slowed GBM growth and disease progression. Finally, mouse and human GBM models have intrinsic circadian rhythms in clock gene expression in vitro and in vivo that entrain to the host through glucocorticoid signaling, regardless of tumor type or host immune status. We conclude that GBM entrains to the circadian circuit of the brain, which modulates its growth through clockcontrolled cues, like glucocorticoids.

Transcriptomic profiling of TLR-7-mediated immune-challenge in zebrafish embryos in the presence and absence of glucocorticoid-induced immunosuppression

Although numerous studies imply a correlation between chemical contamination and an impaired immunocompetence of wildlife populations, the assessment of immunomodulatory modes of action is currently not covered in the regulatory requirements for the approval of new substances. This is not least due to the complexity of the immune system and a lack of standardised methods and validated biomarkers. To tackle this issue, in this study, the transcriptomic profiles of zebrafish embryos were analysed in response to the immunosuppressive compound clobetasol propionate, a synthetic glucocorticoid, and/or the immunostimulatory compound imiquimod (IMQ), a TLR-7 agonist. Using IMQ, known for its potential to induce psoriasis-like effects in mice and human, this study additionally aimed at evaluating the usability of the zebrafish embryo model as an alternative and 3R conform system for the IMQ-induced psoriasis mouse model. Our study substantiates the suitability of previously proposed genes as possible biomarkers for immunotoxicity, such as socs3, nfkbia, anxa1c, fkbp5 and irg1l. Likewise, however, our findings indicate that these genes may be less suitable to distinguish a suppressive from stimulating fashion of action. In contrast, based on a differential regulation in opposite direction in response to both compounds, krt17, rtn4a, and1, smhyc1 and gmpr were identified as potential novel biomarkers with said power to differentiate. Observed IMQ-induced alterations in the expression of genes previously associated with the pathogenesis of psoriasis such as krt17, nfkbia, parp1, pparg, nfil3-6, per2, stat4, klf2, rtn4a, anxa1c and nr1d2 indicate the inducibility of psoriatic effects in the zebrafish embryo. Our work contributes to the establishment of an approach for a 3R-compliant investigation of immunotoxic mechanisms of action in aquatic vertebrates. The validated and newly identified biomarker candidates of specific immunotoxic effects can be used in future studies in the context of environmental hazard assessment of substances or also for human-relevant immunotoxicological questions.

Dexamethasone induces cancer mitigation and irreversible senescence in lung cancer cells via damaging cortical actin and sustained hyperphosphorylation of pRb

Activation of the glucocorticoid receptors by its cognate ligand, dexamethasone (DEX) is commonly used as an adjuvant treatment in solid tumors. However, its direct effect on cancerous phenotype is not fully understood. We explored the effect and molecular mechanisms of DEX action in lung cancer. In in vitro experiments, DEX treatment causes decrease in migration, invasion and colony formation ability of A549 cells even at lower doses. DEX also decreased adhesion of A549 cells by reducing the formation of cortical actin. Treatment with RU486, a GR antagonist, indicated that these effects are partially mediated through GR. Further; DEX induces G0/G1 arrest of A549 cells. Mechanistically, DEX induces expression of both CDK inhibitors (p21Cip1, p27Kip1) and cyclin-dependent kinases (CDK4, CDK6). Due to this compensatory activation of CDKs and CDKIs, DEX induces the hyper phosphorylation state of Rb protein (pRb) leading to irreversible senescence as confirmed by β-gal staining. Next, in clinical dataset of NSCLC (Non-small cell lung cancer), GR was lowly expressed in cancer patients as compared to the normal group, where higher expression of GR led to higher overall survival of NSCLC indicating for a protective role of GR. Interestingly, when combined with chemotherapeutic agents, DEX can modulate the drug-sensitivity of cells. Taken together, these data indicate that DEX through GR activation may suppress tumor growth by decreasing proliferation and inducing irreversible senescence and combination of standard chemotherapy and DEX can be a potential treatment for NSCLC.

Glucocorticoid Receptor Signaling in NSCLC: Mechanistic Aspects and Therapeutic Perspectives

Recent advances in non-small cell lung cancer (NSCLC) biology and the discovery of novel therapeutic targets have led to the development of new pharmacological agents that may improve the clinical outcome of patients with NSCLC. The glucocorticoid receptor (GR) is an evolutionarily conserved protein belonging to the nuclear receptor superfamily of transcription factors and mediates the diverse actions of glucocorticoids in cells. Data suggest that the GR may play a relevant role in the molecular mechanisms of NSCLC tumorigenesis and malignant progression. Additionally, evidence indicates that glucocorticoids may affect the efficacy of standard treatment, including chemotherapy, immune checkpoint inhibitors, and targeted therapy. Furthermore, several findings show that GR expression may probably be associated with NSCLC patient survival. Finally, glucocorticoids may be used as therapeutic agents for the clinical management of NSCLC patients. Here, we briefly review the latest advances on the biological role of GR signaling in NSCLC and discuss the potential use of the GR as a prognostic and predictive biomarker. Importantly, we explore the therapeutic potential of glucocorticoids and the effect of adding such drugs to standard therapies for NSCLC.

Human myeloid progenitor glucocorticoid receptor activation causes genomic instability, type 1 IFN- response pathway activation and senescence in differentiated microglia; an early life stress model

One form of early life stress, prenatal exposure to glucocorticoids (GCs), confers a higher risk of psychiatric and neurodevelopmental disorders in later life. Increasingly, the importance of microglia in these disorders is recognized. Studies on GCs exposure during microglial development have been limited, and there are few, if any, human studies. We established an in vitro model of ELS by continuous pre-exposure of human iPS-microglia to GCs during primitive hematopoiesis (the critical stage of iPS-microglial differentiation) and then examined how this exposure affected the microglial phenotype as they differentiated and matured to microglia, using RNA-seq analyses and functional assays. The iPS-microglia predominantly expressed glucocorticoid receptors over mineralocorticoid receptors, and in particular, the GR-α splice variant. Chronic GCs exposure during primitive hematopoiesis was able to recapitulate in vivo ELS effects. Thus, pre-exposure to prolonged GCs resulted in increased type I interferon signaling, the presence of Cyclic GMP-AMP synthase-positive (cGAS) micronuclei, cellular senescence and reduced proliferation in the matured iPS-microglia. The findings from this in vitro ELS model have ramifications for the responses of microglia in the pathogenesis of GC- mediated ELS-associated disorders such as schizophrenia, attention-deficit hyperactivity disorder and autism spectrum disorder.

Identification of specific susceptibility loci for the early-onset colorectal cancer

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC; patients < 50 years old) has been rising rapidly, whereas the EOCRC genetic susceptibility remains incompletely investigated. Here, we aimed to systematically identify specific susceptible genetic variants for EOCRC.

METHODS

Two parallel GWASs were conducted in 17,789 CRC cases (including 1490 EOCRC cases) and 19,951 healthy controls. A polygenic risk score (PRS) model was built based on identified EOCRC-specific susceptibility variants by using the UK Biobank cohort. We also interpreted the potential biological mechanisms of the prioritized risk variant.

RESULTS

We identified 49 independent susceptibility loci that were significantly associated with the susceptibility to EOCRC and the diagnosed age of CRC (both P < 5.0×10^-4), replicating 3 previous CRC GWAS loci. There are 88 assigned susceptibility genes involved in chromatin assembly and DNA replication pathways, mainly associating with precancerous polyps. Additionally, we assessed the genetic effect of the identified variants by developing a PRS model. Compared to the individuals in the low genetic risk group, the individuals in the high genetic risk group have increased EOCRC risk, and these results were replicated in the UKB cohort with a 1.63-fold risk (95% CI: 1.32-2.02, P = 7.67×10^-6). The addition of the identified EOCRC risk loci significantly increased the prediction accuracy of the PRS model, compared to the PRS model derived from the previous GWAS-identified loci. Mechanistically, we also elucidated that rs12794623 may contribute to the early stage of CRC carcinogenesis via allele-specific regulating the expression of POLA2.

CONCLUSIONS

These findings will broaden the understanding of the etiology of EOCRC and may facilitate the early screening and individualized prevention.

Circadian clock-mediated nuclear receptors in cancer

Circadian system coordinates the daily periodicity of physiological and biochemical functions to adapt to environmental changes. Circadian disruption has been identified to increase the risk of cancer and promote cancer progression, but the underlying mechanism remains unclear. And further mechanistic understanding of the crosstalk between clock components and cancer is urgent to achieve clinical anticancer benefits from chronochemotherapy. Recent studies discover that several nuclear receptors regulating circadian clock, also play crucial roles in mediating multiple cancer processes. In this review, we aim to summarize the latest developments of clock-related nuclear receptors in cancer biology and dissect mechanistic insights into how nuclear receptors coordinate with circadian clock to regulate tumorigenesis and cancer treatment. A better understanding of circadian clock-related nuclear receptors in cancer could help prevent tumorigenesis and improve anticancer efficacy.

Network pharmacology and in vitro experiments-based strategy to investigate the mechanisms of KangXianYiAi formula for hepatitis B virus-related hepatocellular carcinoma

The Chinese traditional medicine KangXianYiAi formula (KXYA) is used to treat hepatic disease in the clinic. Here we aim to confirm the therapeutic effects and explore the pharmacological mechanisms of KXYA on hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). We first collected and analyzed clinical data of 40 chronic hepatitis B (CHB) patients with precancerous liver lesions under KXYA treatment. Then, the cell viability, migration, cell cycle, and apoptosis of HepAD38 cells with KXYA treatment were examined. Next, we performed network pharmacological analysis based on database mining to obtain the key target pathways and genes of KXYA treatment on HBV-related HCC. We finally analyzed the expression of the key genes between normal and HBV-related HCC tissues in databases and measured the mRNA expression of the key genes in HepAD38 cells after KXYA treatment. The KXYA treatment could reduce the liver nodule size of CHB patients, suppress the proliferation and migration capabilities, and promote apoptosis of HepAD38 cells. The key pathways of KXYA on HBV-related HCC were Cancer, Hepatitis B, Viral carcinogenesis, Focal adhesion, and PI3K-Akt signaling, and KXYA treatment could regulate the expression of the key genes including HNF4A, MAPK8, NR3C1, PTEN, EGFR, and HDAC1. The KXYA exhibited a curative effect via inhibiting proliferation, migration, and promoting apoptosis of HBV-related HCC and the pharmacological mechanism was related to the regulation of the expression of HNF4A, MAPK8, NR3C1, PTEN, EGFR, and HDAC1.

Application of two-dimensional difference gel electrophoresis to identify protein changes between center, margin, and adjacent non-tumor tissues obtained from non-small-cell lung cancer with adenocarcinoma or squamous cell carcinoma subtype

Lung cancer is responsible for the most cancer-related mortality worldwide and the mechanism of its development is poorly understood. Proteomics has become a powerful tool offering vital knowledge related to cancer development. Using a two-dimensional difference gel electrophoresis (2D-DIGE) approach, we sought to compare tissue samples from non-small-cell lung cancer (NSCLC) patients taken from the tumor center and tumor margin. Two subtypes of NSCLC, adenocarcinoma (ADC) and squamous cell carcinoma (SCC) were compared. Data are available via ProteomeXchange with identifier PXD032736 and PXD032962 for ADC and SCC, respectively. For ADC proteins, 26 significant canonical pathways were identified, including Rho signaling pathways, a semaphorin neuronal repulsive signaling pathway, and epithelial adherens junction signaling. For SCC proteins, nine significant canonical pathways were identified, including hypoxia-inducible factor-1α signaling, thyroid hormone biosynthesis, and phagosome maturation. Proteins differentiating the tumor center and tumor margin were linked to cancer invasion and progression, including cell migration, adhesion and invasion, cytoskeletal structure, protein folding, anaerobic metabolism, tumor angiogenesis, EMC transition, epithelial adherens junctions, and inflammatory responses. In conclusion, we identified several proteins that are important for the better characterization of tumor development and molecular specificity of both lung cancer subtypes. We also identified proteins that may be important as biomarkers and/or targets for anticancer therapy.

The glucocorticoid receptor associates with RAS complexes to inhibit cell proliferation and tumor growth

Mutations that activate members of the RAS family of GTPases are associated with various cancers and drive tumor growth. The glucocorticoid receptor (GR), a member of the nuclear receptor family, has been proposed to interact with and inhibit the activation of components of the PI3K-AKT and MAPK pathways downstream of RAS. In the absence of activating ligands, we found that GR was present in cytoplasmic KRAS-containing complexes and inhibited the activation of wild-type and oncogenic KRAS in mouse embryonic fibroblasts and human lung cancer A549 cells. The DNA binding domain of GR was involved in the interaction with KRAS, but GR-dependent inhibition of RAS activation did not depend on the nuclear translocation of GR. The addition of ligand released GR-dependent inhibition of RAS, AKT, the MAPK p38, and the MAPKK MEK. CRISPR-Cas9-mediated deletion of GR in A549 cells enhanced tumor growth in xenografts in mice. Patient samples of non-small cell lung carcinomas showed lower expression of NR3C1, the gene encoding GR, compared to adjacent normal tissues and lower NR3C1 expression correlated with a worse disease outcome. These results suggest that glucocorticoids prevent the ability of GR to limit tumor growth by inhibiting RAS activation, which has potential implications for the use of glucocorticoids in patients with cancer.

Corticosteroid Receptors in Cardiac Health and Disease

Nuclear receptors play a central role in both energy metabolism and cardiomyocyte death and survival in the heart. Recent evidence suggests they may also influence cardiomyocyte endowment. Although several members of the nuclear receptor family play key roles in heart maturation (including thyroid hormone receptors) and cardiac metabolism, here, the focus will be on the corticosteroid receptors, the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). The heart is an important target for the actions of corticosteroids, yet the homeostatic role of GR and MR in the healthy heart has been elusive. However, MR antagonists are important in the treatment of heart failure, a condition associated with mitochondrial dysfunction and energy failure in cardiomyocytes leading to mitochondria-initiated cardiomyocyte death (Ingwall and Weiss, Circ Res 95:135-145, 2014; Ingwall , Cardiovasc Res 81:412-419, 2009; Zhou and Tian , J Clin Invest 128:3716-3726, 2018). In contrast, animal studies suggest GR activation in cardiomyocytes has a cardioprotective role, including in heart failure.

Centrosome Aberrations as Drivers of Chromosomal Instability in Breast Cancer

Chromosomal instability (CIN), or the dynamic change in chromosome number and composition, has been observed in cancer for decades. Recently, this phenomenon has been implicated as facilitating the acquisition of cancer hallmarks and enabling the formation of aggressive disease. Hence, CIN has the potential to serve as a therapeutic target for a wide range of cancers. CIN in cancer often occurs as a result of disrupting key regulators of mitotic fidelity and faithful chromosome segregation. As a consequence of their essential roles in mitosis, dysfunctional centrosomes can induce and maintain CIN. Centrosome defects are common in breast cancer, a heterogeneous disease characterized by high CIN. These defects include amplification, structural defects, and loss of primary cilium nucleation. Recent studies have begun to illuminate the ability of centrosome aberrations to instigate genomic flux in breast cancer cells and the tumor evolution associated with aggressive disease and poor patient outcomes. Here, we review the role of CIN in breast cancer, the processes by which centrosome defects contribute to CIN in this disease, and the emerging therapeutic approaches that are being developed to capitalize upon such aberrations.

Intestinal epithelial glucocorticoid receptor promotes chronic inflammation-associated colorectal cancer

Synthetic immunosuppressive glucocorticoids (GCs) are widely used to control inflammatory bowel disease (IBD). However, the impact of GC signaling on intestinal tumorigenesis remains controversial. Here, we report that intestinal epithelial GC receptor (GR), but not whole intestinal tissue GR, promoted chronic intestinal inflammation-associated colorectal cancer in both humans and mice. In patients with colorectal cancer, GR was enriched in intestinal epithelial cells and high epithelial cell GR levels were associated with poor prognosis. Consistently, intestinal epithelium–specific deletion of GR (GR iKO) in mice increased macrophage infiltration, improved tissue recovery, and enhanced antitumor response in a chronic inflammation–associated colorectal cancer model. Consequently, GR iKO mice developed fewer and less advanced tumors than control mice. Furthermore, oral GC administration in the early phase of tissue injury delayed recovery and accelerated the formation of aggressive colorectal cancers. Our study reveals that intestinal epithelial GR signaling repressed acute colitis but promoted chronic inflammation–associated colorectal cancer. Our study suggests that colorectal epithelial GR could serve as a predictive marker for colorectal cancer risk and prognosis. Our findings further suggest that, although synthetic GC treatment for IBD should be used with caution, there is a therapeutic window for GC therapy during colorectal cancer development in immunocompetent patients.

Glucocorticoid and PD-1 Cross-Talk: Does the Immune System Become Confused?

Programmed cell death protein 1 (PD-1) and its ligands, PD-L1/2, control T cell activation and tolerance. While PD-1 expression is induced upon T cell receptor (TCR) activation or cytokine signaling, PD-L1 is expressed on B cells, antigen presenting cells, and on non-immune tissues, including cancer cells. Importantly, PD-L1 binding inhibits T cell activation. Therefore, the modulation of PD-1/PD-L1 expression on immune cells, both circulating or in a tumor microenvironment and/or on the tumor cell surface, is one mechanism of cancer immune evasion. Therapies that target PD-1/PD-L1, blocking the T cell-cancer cell interaction, have been successful in patients with various types of cancer. Glucocorticoids (GCs) are often administered to manage the side effects of chemo- or immuno-therapy, exerting a wide range of immunosuppressive and anti-inflammatory effects. However, GCs may also have tumor-promoting effects, interfering with therapy. In this review, we examine GC signaling and how it intersects with PD-1/PD-L1 pathways, including a discussion on the potential for GC- and PD-1/PD-L1-targeted therapies to "confuse" the immune system, leading to a cancer cell advantage that counteracts anti-cancer immunotherapy. Therefore, combination therapies should be utilized with an awareness of the potential for opposing effects on the immune system.

Investigating the Mechanism of Scutellariae barbata Herba in the Treatment of Colorectal Cancer by Network Pharmacology and Molecular Docking

Background

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors, which accounts for approximately 10% of all diagnosed cancers and cancer deaths worldwide per year. Scutellariae barbatae Herba (SBH) is one of the most frequently used traditional Chinese medicine (TCM) in the treatment of CRC. Although many experiments have been carried out to explain the mechanisms of SBH, the mechanisms of SBH have not been illuminated fully. Thus, we constructed a network pharmacology and molecular docking to investigate the mechanisms of SBH.

Methods

We adopted active constituent prescreening, target predicting, protein-protein interaction (PPI) analysis, Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, differentially expressed gene analysis, and molecular docking to establish a system pharmacology database of SBH against CRC.

Results

A total of 64 active constituents of SBH were obtained and 377 targets were predicted, and the result indicated that quercetin, luteolin, wogonin, and apigenin were the main active constituents of SBH. Glucocorticoid receptor (NR3C1), pPhosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA), cellular tumor antigen p53 (TP53), transcription factor AP-1 (JUN), mitogen-activated protein kinase 1 (MAPK1), Myc protooncogene protein (MYC), cyclin-dependent kinase 1 (CDK1), and broad substrate specificity ATP-binding cassette transporter ABCG2 (ABCG2) were the major targets of SBH in the treatment of CRC. GO analysis illustrated that the core biological process regulated by SBH was the regulation of the cell cycle. Thirty pathways were presented and 8 pathways related to CRC were involved. Molecular docking presented the binding details of 3 key targets with 6 active constituents.

Conclusions

The mechanisms of SBH against CRC depend on the synergistic effect of multiple active constituents, multiple targets, and multiple pathways.

Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer

The glucocorticoid receptor (GR) regulates gene expression, governing aspects of homeostasis, but is also involved in cancer. Pharmacological GR activation is frequently used to alleviate therapy-related side-effects. While prior studies have shown GR activation might also have anti-proliferative action on tumours, the underpinnings of glucocorticoid action and its direct effectors in non-lymphoid solid cancers remain elusive. Here, we study the mechanisms of glucocorticoid response, focusing on lung cancer. We show that GR activation induces reversible cancer cell dormancy characterised by anticancer drug tolerance, and activation of growth factor survival signalling accompanied by vulnerability to inhibitors. GR-induced dormancy is dependent on a single GR-target gene, CDKN1C, regulated through chromatin looping of a GR-occupied upstream distal enhancer in a SWI/SNF-dependent fashion. These insights illustrate the importance of GR signalling in non-lymphoid solid cancer biology, particularly in lung cancer, and warrant caution for use of glucocorticoids in treatment of anticancer therapy related side-effects.

Glucocorticoid Receptor: A Multifaceted Actor in Breast Cancer

Breast cancer (BC) is one of the most common cancers in women worldwide. Even though the role of estrogen receptor alpha (ERα) is extensively documented in the development of breast tumors, other members of the nuclear receptor family have emerged as important players. Synthetic glucocorticoids (GCs) such as dexamethasone (dex) are commonly used in BC for their antiemetic, anti-inflammatory, as well as energy and appetite stimulating properties, and to manage the side effects of chemotherapy. However, dex triggers different effects depending on the BC subtype. The glucocorticoid receptor (GR) is also an important marker in BC, as high GR expression is correlated with a poor and good prognosis in ERα-negative and ERα-positive BCs, respectively. Indeed, though it drives the expression of pro-tumorigenic genes in ERα-negative BCs and is involved in resistance to chemotherapy and metastasis formation, dex inhibits estrogen-mediated cell proliferation in ERα-positive BCs. Recently, a new natural ligand for GR called OCDO was identified. OCDO is a cholesterol metabolite with oncogenic properties, triggering mammary cell proliferation in vitro and in vivo. In this review, we summarize recent data on GR signaling and its involvement in tumoral breast tissue, via its different ligands.

Prognostic Significance of Glucocorticoid Receptor Expression in Cancer: A Systematic Review and Meta-Analysis

Simple Summary

In solid tumours, emerging evidence indicates that signalling through the glucocorticoid receptor (GR) can encourage the growth and spread of tumours and so drugs targeting this receptor are in development for use in cancer treatment. For these reasons, GR may be useful in anticipating a patient’s outcome upon their cancer diagnosis or to predict their tumours response to drugs targeting this receptor. In this review we aim to ascertain whether GR expression in tumours affects cancer patient survival. Overall, GR expression did not affect patient survival when assessing all cancer types. However, we found that in certain cancer subtypes such as gynaecological cancers (endometrial and ovarian) and early stage, untreated triple negative breast cancers, high GR expression is linked with cancer progression and therefore a poorer patient prognosis. Further studies are needed to uncover the exact role of GR in specific tumour (sub)types in order to provide the correct patients with GR targeting therapies.

Abstract

In solid malignancies, the glucocorticoid receptor (GR) signalling axis is associated with tumour progression and GR antagonists are in clinical development. Therefore, GR expression may be a useful potential prognostic or predictive biomarker for GR antagonist therapy in cancer. The aim of this review is to investigate if GR expression in tumours is predictive of overall survival or progression free survival. Twenty-five studies were identified through systematic searches of three databases and a meta-analysis conducted using a random effects model, quantifying statistical heterogeneity. Subgroup analysis was conducted for cancer types and publication bias was assessed via funnel plots. There was high heterogeneity in meta-analysis of the studies in all cancer types, which found no association between high GR expression with overall survival (pooled unadjusted HR 1.16, 95% CI (0.89–1.50), n = 2814; pooled adjusted HR 1.02, 95% CI (0.77–1.37), n = 2355) or progression-free survival (pooled unadjusted HR 1.12, 95% CI (0.88–1.42), n = 3365; pooled adjusted HR 1.04, 95% CI (0.6–1.81), n = 582) across all cancer types. However, subgroup meta-analyses showed that high GR expression in gynaecological cancers (endometrial and ovarian) (unadjusted HR 1.83, 95% CI (1.31–2.56), n = 664) and early stage, untreated triple negative breast cancers (TNBCs) (unadjusted HR 1.73, 95% CI (1.35–2.23), n = 687) is associated with disease progression. GR expression in late stage, chemotherapy treated TNBC was not prognostic (unadjusted HR 0.76, 95% CI (0.44, 1.32), n = 287). In conclusion, high GR expression is associated with an increased risk of disease progression in gynaecological and early stage, untreated TNBC. Additional studies are required to elucidate the tumour specific function of the GR receptor in order to ensure GR antagonists target the correct patient groups.

Nuclear receptors: Lipid and hormone sensors with essential roles in the control of cancer development

Nuclear receptors (NRs) are a superfamily of ligand-activated transcription factors that act as biological sensors and use a combination of mechanisms to modulate positively and negatively gene expression in a spatial and temporal manner. The highly orchestrated biological actions of several NRs influence the proliferation, differentiation, and apoptosis of many different cell types. Synthetic ligands for several NRs have been the focus of extensive drug discovery efforts for cancer intervention. This review summarizes the roles in tumour growth and metastasis of several relevant NR family members, namely androgen receptor (AR), estrogen receptor (ER), glucocorticoid receptor (GR), thyroid hormone receptor (TR), retinoic acid receptors (RARs), retinoid X receptors (RXRs), peroxisome proliferator-activated receptors (PPARs), and liver X receptors (LXRs). These studies are key to develop improved therapeutic agents based on novel modes of action with reduced side effects and overcoming resistance.

Proteomics evaluation of MDA-MB-231 breast cancer cells in response to RNAi-induced silencing of hPTTG

AIMS

Breast cancer is the most common cancer in women worldwide. Several genes are up-regulated in breast cancer such as human pituitary tumor transforming gene (hPTTG). This study aims to evaluate cell proliferation and the downstream expression pattern of hPTTG1 gene at the mRNA and protein levels after specific down-regulation of hPTTG1 by siRNA.

MAIN METHODS

The human breast cancer MDA-MB-231 cell line was transfected with siRNA against hPTTG1. The mRNA and protein expression levels were examined by Real-time PCR and Western blot, respectively. The cell proliferation was assayed by MTS. To investigate the pattern of protein expression, total cellular protein was analyzed by 2D gel electrophoresis and mass spectroscopy. Subsequently, the possible biological consequences were determined by the bioinformatics databases.

KEY FINDINGS

Subsequent of hPTTG1 silencing in the MDA_MB-231 cells, the proliferation of cells decreased obviously. In response to hPTTG1 silencing, the levels mRNA and protein were effectively down-regulated 80% and 50%, respectively, at 48 h post-transfection. The proteomics evidenced that PTTG1 increased the expression of 5 proteins. The reduced expression of PTTG1 was functionally involved in hypoxia (NPM1, ENO1), cell proliferation and apoptosis (ENO1, NPM1, NME1, STMN1), and metastasis (NPM1, NME1).

SIGNIFICANCE

We identified the hPTTG1-regulated proteins and its molecular mechanism in pathogenesis of breast cancer. Further study emphasis is to understand the association of hPTTG1 with other genes in cancer progression. This novel modality might also consider for identification of targeted drugs, prognosis and follow up in breast cancer gene therapy.

Reciprocal and Autonomous Glucocorticoid and Androgen Receptor Activation in Salivary Duct Carcinoma

PURPOSE

To determine the expression of glucocorticoid receptor (GR) and androgen receptor (AR) in salivary duct carcinoma (SDC) and to analyze the role of these proteins in the development and management of this disease entity.

EXPERIMENTAL DESIGN

We performed a phenotypic assessment of GR and AR localization and expression, and determined their association with clinicopathologic factors in 67 primary SDCs. In vitro functional and response analysis of SDC cell lines was also performed.

RESULTS

Of the 67 primary tumors, 12 (18%) overexpressed GR protein, 30 (45%) had constitutive expression, and 25 (37%) had complete loss of expression. Reciprocal GR and AR expression was found in 32 (48%) tumors, concurrent constitutive GR and AR expression in 23 (34%), and simultaneous loss of both receptors and high GR with AR expressions were found in 12 (18%). GR overexpression was significantly associated with worse clinical outcomes. In vitro ligand-independent AR activation was observed in both male- and female-derived cell lines. GR antagonist treatment resulted in decreased cell proliferation and survival in GR-overexpressing cells, irrespective of AR status. Reciprocal GR- and AR-knockdown experiments revealed an independent interaction.

CONCLUSIONS

Our study, for the first time, demonstrates differential GR and AR expressions, autonomous GR and AR activation, and ligand-independent AR expression and activation in SDC cells. The findings provide critical information on the roles of GR and AR steroid receptors in SDC tumorigenesis and development of biomarkers to guide targeted steroid receptor therapy trials in patients with these tumors.

Ibrutinib reprograms the glucocorticoid receptor in chronic lymphocytic leukemia cells

Glucocorticoid (GC) receptor (GR) phosphorylation and signature genes were studied in chronic lymphocytic leukemia (CLL) cells to help place GCs within modern treatment algorithms. In contrast to normal B and T cells, transcription of GC-regulated genes was not rhythmic and the synthetic GC dexamethasone (DEX) could not inhibit toll-like receptor (TLR)-responses in CLL cells. This intrinsic GC-resistance was associated with aberrant GR-phosphorylation on activating Ser211 and inhibitory Ser226 sites. Ibrutinib increased transcription of the GR-signature gene GILZ in circulating CLL cells along with GR(pS211)/GR(pS226) ratios and lytic sensitivity to DEX that were not reversed by the competitive antagonist mifepristone in vitro. However, ibrutinib could not improve GR-responses in circulating CLL cells activated with IL2 and TLR7/8 agonists to mimic conditions in pseudofollicle microenvironments. Addition of the janus kinase inhibitor ruxolitinib to block ibrutinib-insensitive signals increased GILZ transcription in pseudofollicle conditions in vitro and in a clinical trial (NCT02912754), and also increased GR(S211)/GR(S226) ratios and DEX-mediated killing in patient samples in vitro. These observations suggest that intrinsic resistance to endogenous GCs is characteristic of CLL cells and ibrutinib may help increase the therapeutic activity of GCs by non-canonical activation of GR.

From the Cover: Genomic Effects of Androstenedione and Sex-Specific Liver Cancer Susceptibility in Mice

Current strategies for predicting carcinogenic mode of action for nongenotoxic chemicals are based on identification of early key events in toxicity pathways. The goal of this study was to evaluate short-term key event indicators resulting from exposure to androstenedione (A4), an androgen receptor agonist and known liver carcinogen in mice. Liver cancer is more prevalent in men compared with women, but androgen-related pathways underlying this sex difference have not been clearly identified. Short-term hepatic effects of A4 were compared with reference agonists of the estrogen receptor (ethinyl estradiol, EE) and glucocorticoid receptor (prednisone, PRED). Male B6C3F1 mice were exposed for 7 or 28 days to A4, EE, or PRED. EE increased and PRED suppressed hepatocyte proliferation, while A4 had no detectable effects. In a microarray analysis, EE and PRED altered >3000 and >670 genes, respectively, in a dose-dependent manner, whereas A4 did not significantly alter any genes. Gene expression was subsequently examined in archival liver samples from male and female B6C3F1 mice exposed to A4 for 90 days. A4 altered more genes in females than males and did not alter expression of genes linked to activation of the mitogenic xenobiotic receptors AhR, CAR, and PPARα in either sex. A gene expression biomarker was used to show that in female mice, the high dose of A4 activated the growth hormone-regulated transcription factor STAT5b, which controls sexually dimorphic gene expression in the liver. These findings suggest that A4 induces subtle age-related effects on STAT5b signaling that may contribute to the higher risk of liver cancer in males compared with females.

Possible roles for glucocorticoid signalling in breast cancer

Our understanding of breast cancer biology, and our ability to manipulate breast cancers have grown exponentially in the last 20 years. Much of that expansion has focused on the roles of steroids in driving these neoplasms. Initially this research focused on estrogens and progesterone receptors, and more recently on androgen actions in breast cancers. This review aims to make the case for glucocorticoids as the next essential steroid subclass that contributes significantly to our understanding of steroidogenic regulation of these neoplasms. Glucocorticoids have the potential to play multiple roles in the regulation of breast cancers including their control of cellular differentiation, apoptosis and proliferation. Beyond this they also act as a master integrator of organ homeostats in relation to such as circadian rhythms and stress responses. Therefore a better understanding of glucocorticoids and breast cancer could help to explain some of the epidemiological links between circadian disruption and/or stress and breast cancer development. Finally glucocorticoids are currently used during chemotherapeutic treatment in breast cancer therapy and yet results of various studies suggest that this may have an adverse impact on treatment success. This review aims to summarise the current evidence for glucocorticoids as actors in breast cancer and then suggest future essential approaches in order to determine the roles of glucocorticoids in this disease.

A dual role for glucocorticoid-induced leucine zipper in glucocorticoid function: tumor growth promotion or suppression?

Glucocorticoids (GCs), important therapeutic tools to treat inflammatory and immunosuppressive diseases, can also be used as part of cancer therapy. In oncology, GCs are used as anticancer drugs for lymphohematopoietic malignancies, while in solid neoplasms primarily to control the side effects of chemo/radiotherapy treatments. The molecular mechanisms underlying the effects of GCs are numerous and often overlapping, but not all have been elucidated. In normal, cancerous, and inflammatory tissues, the response to GCs differs based on the tissue type. The effects of GCs are dependent on several factors: the tumor type, the GC therapy being used, the expression level of the glucocorticoid receptor (GR), and the presence of any other stimuli such as signals from immune cells and the tumor microenvironment. Therefore, GCs may either promote or suppress tumor growth via different molecular mechanisms. Stress exposure results in dysregulation of the hypothalamic-pituitary-adrenal axis with increased levels of endogenous GCs that promote tumorigenesis, confirming the importance of GCs in tumor growth. Most of the effects of GCs are genomic and mediated by the modulation of GR gene transcription. Moreover, among the GR-induced genes, glucocorticoid-induced leucine zipper (GILZ), which was cloned and characterized primarily in our laboratory, mediates many GC anti-inflammatory effects. In this review, we analyzed the possible role for GILZ in the effects GCs have on tumors cells. We also suggest that GILZ, by affecting the immune system, tumor microenvironment, and directly cancer cell biology, has a tumor-promoting function. However, it may also induce apoptosis or decrease the proliferation of cancer cells, thus inhibiting tumor growth. The potential therapeutic implications of GILZ activity on tumor cells are discussed here.

Chromosome 7 Multiplication in EGFR-positive Lung Carcinomas Based on Tissue Microarray Analysis

BACKGROUND/AIM

Epidermal growth factor receptor (EGFR) over-activation is observed in significant proportions of non-small cell lung carcinomas (NSCLC). Our aim was to investigate the role of chromosome 7 multiplication with regard to its influence in EGFR expression, combined or not with gene amplification.

MATERIALS AND METHODS

Using tissue microarray technology, fifty (n=50) primary NSCLCs were cored and re-embedded into the final recipient block. Immunohistochemistry (IHC) and also chromogenic in situ hybridization (CISH) were performed.

RESULTS

EGFR expression at any level was detected in 40/50 (80%) cores. Over-expression was observed in 23/40 (57.5%) cases. Gene amplification was identified in 11/50 (22%) cases whereas chromosome 7 polysomy in 8/50 (16%) cases. Pure chromosome 7 multiplication alone led to low or moderate levels of expression. Overall EGFR expression was correlated with gene (p=0.001) and interestingly with chromosome 7 centromere numerical imbalances (p=0.004).

CONCLUSION

EGFR expression is associated not only with amplification, but also with chromosome 7 centromere multiple copies. Chromosome 7 multiplication -due to centromere region amplification or true polysomy- is critical for applying monoclonal antibody targeted therapeutic strategies excluding the pure non-amplified cases.

The tobacco carcinogen NNK drives accumulation of DNMT1 at the GR promoter thereby reducing GR expression in untransformed lung fibroblasts

Small cell lung cancer (SCLC) is a highly aggressive, predominantly cigarette smoke-induced tumour with poor prognosis. The glucocorticoid receptor (GR), a SCLC tumour suppressor gene, is typically reduced in SCLC. We now show that SCLC cells express high levels of DNA methyltransferase 1 (DNMT1) which accumulates at the GR promoter. DNMT1 expression is further increased by exposure to the tobacco carcinogen NNK. In the untransformed human lung fibroblast cell line, MRC-5, short term NNK treatment decreases GRα mRNA and protein expression due to accumulation of DNMT1 at the GR promoter. Long term NNK treatment results in persistently augmented DNMT1 levels with lowered GR levels. Long term exposure to NNK slows cell proliferation and induces DNA damage, while the GR antagonist RU486 stimulates proliferation and protects against DNA damage. Although both NNK and RU486 treatment increases methylation at the GR promoter, neither are sufficient to prevent senescence in this context. NNK exposure results in accumulation of DNMT1 at the GR promoter in untransformed lung cells mimicking SCLC cells, directly linking tobacco smoke exposure to silencing of the GR, an important step in SCLC carcinogenesis.

Dexamethasone mediates pancreatic cancer progression by glucocorticoid receptor, TGFβ and JNK/AP-1

Glucocorticoids such as dexamethasone are widely co-prescribed with cytotoxic therapy because of their proapoptotic effects in lymphoid cancer, reduction of inflammation and edema and additional benefits. Concerns about glucocorticoid-induced therapy resistance, enhanced metastasis and reduced survival of patients are largely not considered. We analyzed dexamethasone-induced tumor progression in three established and one primary human pancreatic ductal adenocarcinoma (PDA) cell lines and in PDA tissue from patients and xenografts by FACS and western blot analysis, immunohistochemistry, MTT and wound assay, colony and spheroid formation, EMSA and in vivo tumor growth and metastasis of tumor xenografts on chicken eggs and mice. Dexamethasone in concentrations observed in plasma of patients favored epithelial–mesenchymal transition, self-renewal potential and cancer progression. Ras/JNK signaling, enhanced expression of TGFβ, vimentin, Notch-1 and SOX-2 and the inhibition of E-cadherin occurred. This was confirmed in patient and xenograft tissue, where dexamethasone induced tumor proliferation, gemcitabine resistance and metastasis. Inhibition of each TGFβ receptor-I, glucocorticoid receptor or JNK signaling partially reversed the dexamethasone-mediated effects, suggesting a complex signaling network. These data reveal that dexamethasone mediates progression by membrane effects and binding to glucocorticoid receptor.

A non-transcriptional role for the glucocorticoid receptor in mediating the cell stress response

The glucocorticoid receptor (GR) is essential for the stress response in mammals. We investigated potential non-transcriptional roles of GR in cellular stress response using fission yeast as a model.We surprisingly discovered marked heat stress resistance in yeast ectopically expressing human GR, which required expression of both the N-terminal transactivation domain, and the C-terminal ligand binding domain, but not the DNA-binding domain of the GR. This effect was not affected by GR ligand exposure, and occurred without significant GR nuclear accumulation. Mechanistically, the GR survival effect required Hsp104, and, indeed, GR expression increased Hsp104 expression. Proteomic analysis revealed GR binding to translasome components, including eIF3, a known partner for Sty1, a pattern of protein interaction which we confirmed using yeast two-hybrid studies.Taken together, we find evidence for a novel pathway conferring stress resistance in yeast that can be activated by the human GR, acting by protein-protein mechanisms in the cytoplasm. This suggests that in organisms where GR is natively expressed, GR likely contributes to stress responses through non-transcriptional mechanisms in addition to its well-established transcriptional responses.

Histone demethylase JMJD2C: epigenetic regulators in tumors

Histone methylation is one of the major epigenetic modifications, and various histone methylases and demethylases participate in the epigenetic regulating. JMJD2C has been recently identified as one of the histone lysine demethylases. As one member of the Jumonji-C histone demethylase family, JMJD2C has the ability to demethylate tri- or di-methylated histone 3 and 2 in either K9 (lysine residue 9) or K36 (lysine residue 36) sites by an oxidative reaction, thereby affecting heterochromatin formation, genomic imprinting, X-chromosome inactivation, and transcriptional regulation of genes. JMJD2C was firstly found to involve in embryonic development and stem cell regulation. Afterwards, aberrant status of JMJD2C histone methylation was observed during the formation and development of various tumors, and it has been reported to play crucial roles in the progression of breast cancer, prostate carcinomas, osteosarcoma, blood neoplasms and so on, indicating that JMJD2C represents a promising anti-cancer target. In this review, we will focus on the research progress and prospect of JMJD2C in tumors, and provide abundant evidence for the functional application and therapeutic potential of targeting JMJD2C in tumors.

MUC16 Regulates TSPYL5 for Lung Cancer Cell Growth and Chemoresistance by Suppressing p53

Purpose: MUC16, a tumor biomarker and cell surface-associated mucin, is overexpressed in various cancers; however, its role in lung cancer pathogenesis is unknown. Here, we have explored the mechanistic role of MUC16 in lung cancer.Experimental Design: To identify the functional role of MUC16, stable knockdown was carried in lung cancer cells with two different shRNAs. Clinical significance of MUC16 was evaluated in lung cancer patient tissues using IHC. We have generated genetically engineered mouse model (Kras^G12D; AdCre) to evaluate the preclinical significance of MUC16.Results: MUC16 was overexpressed (P = 0.03) in lung cancer as compared with normal tissues. MUC16 knockdown (KD) in lung cancer cell lines decreased the in vitro growth rate (P < 0.05), migration (P < 0.001), and in vivo tumor growth (P = 0.007), whereas overexpression of MUC16-carboxyl terminal (MUC16-Cter) resulted in increased growth rate (P < 0.001). Transcriptome analysis of MUC16 KD showed a downregulation (P = 0.005) of TSPYL5 gene, which encodes for a testis-specific Y-like protein. Rescue studies via overexpression of MUC16-Cter in MUC16 KD cells showed activation of signaling proteins, such as JAK2 (Y1007/1008), STAT3 (Y705), and glucocorticoid receptor (GR), which constitutes an important axis for the regulation of TSPYL5 for oncogenic process. Further, inhibition of STAT3 (Y705) led to decreased GR and TSPYL5, suggesting that MUC16 regulates TSPYL5 through the JAK2/STAT3/GR axis. Also, MUC16 overexpression induced cisplatin and gemcitabine resistance by downregulation of p53.Conclusions: Our findings indicate a significant role of MUC16 in tumorigenesis and metastasis of lung cancer cells possibly via regulation of TSPYL5 through the JAK2/STAT3/GR axis. Clin Cancer Res; 23(14); 3906-17. ©2017 AACR.

The role of glucocorticoid receptor in prostate cancer progression: from bench to bedside

Glucocorticoids are a common class of adjuvant drugs for the treatment of castration-resistant prostate cancer (CRPC) combined with antitumour or antiandrogen agents. Glucocorticoids are administered clinically because they ameliorate toxic side effects and have inhibitory effects on adrenal androgen production, acting as a pituitary suppressant. However, their effects on prostate cancer cells especially the castration resistance prostate cancer cells are poorly defined. Glucocorticoids exert effects depend to a great extent on glucocorticoid receptor. In addition to a number of glucocorticoid receptor isoforms determined, it is found that the actions of glucocorticoids through GRα are influenced by other isoforms, such as GRβ and GRγ. Recently, studies found GR confers resistance to androgen deprivation therapy, and various glucocorticoids exert distinct efficacy in CRPC. In this review, we summarized the mechanisms of glucocorticoids and its clinical appliances on the basis of present evidence.

Expression of the glucocorticoid receptor in breast cancer-associated fibroblasts

Cancer- associated fibroblasts (CAFs) are actively involved in breast carcinoma. Our previous study demonstrated that the majority of these CAFs were smooth muscle actin (SMA) positive and were therefore termed peritumoral myofibroblast (PMY). Glucocorticoid, linked or not with its receptor (GR), has been postulated to serve a major role in normal breast and breast carcinoma; however, their role in CAFs remains poorly understood. The aim of the present study was to assess the presence of GR in breast CAFs and particularly in PMY in 56 cases of invasive breast carcinoma in correlation with clinicopathological parameters, by immunohistochemistry. GR was observed in CAFs in 51 cases (91%) and were more frequent in luminal A subtype (19/19 cases; 100%). The stromal expression was statistically correlated with the tumor grade (P=0.03), the Ki-67 index (P=0.003) and the presence of GR in the epithelial component (P=0.01). The demonstration of a frequent expression of GR in breast CAFs may serve as an interesting target for future therapeutics for the regulation of the tumoral breast microenvironment.

Association of lifestyle and demographic factors with estrogenic and glucocorticogenic activity in Mexican American women

Breast cancer risk is higher in US-born than in foreign-born Hispanics/Latinas and also increases with greater length of US residency. It is only partially known what factors contribute to these patterns of risk. To gain new insights, we tested the association between lifestyle and demographic variables and breast cancer status, with measures of estrogenic (E) and glucocorticogenic (G) activity in Mexican American women. We used Chemical-Activated LUciferase gene eXpression assays to measure E and G activity in total plasma from 90 Mexican American women, without a history of breast cancer at the time of recruitment, from the San Francisco Bay Area Breast Cancer Study. We tested associations of nativity, lifestyle and sociodemographic factors with E and G activity using linear regression models. We did not find a statistically significant difference in E or G activity by nativity. However, in multivariable models, E activity was associated with Indigenous American ancestry (19% decrease in E activity per 10% increase in ancestry, P = 0.014) and with length of US residency (28% increase in E activity for every 10 years, P = 0.035). G activity was associated with breast cancer status (women who have developed breast cancer since recruitment into the study had 21% lower G activity than those who have not, P = 0.054) and alcohol intake (drinkers had 25% higher G activity than non-drinkers, P = 0.015). These associations suggest that previously reported breast cancer risk factors such as genetic ancestry and alcohol intake might in part be associated with breast cancer risk through mechanisms linked to the endocrine system.

Glucocorticoid-independent modulation of GR activity: Implications for immunotherapy

Pharmacological doses of glucocorticoids (GCs), acting via the glucocorticoid receptor (GR) to repress inflammation and immune function, remain the most effective therapy in the treatment of inflammatory and immune diseases. Since many patients on GC therapy exhibit GC resistance and severe side-effects, much research is focused on developing more selective GCs and combination therapies, with greater anti-inflammatory potency. GCs mediate their classical genomic transcriptional effects by binding to the cytoplasmic GR, followed by nuclear translocation and modulation of transcription of target genes by direct DNA binding of the GR or its tethering to other transcription factors. Recent evidence suggests, however, that the responses mediated by the GR are much more complex and involve multiple parallel mechanisms integrating simultaneous signals from other receptors, both in the absence and presence of GCs, to shift the sensitivity of a target cell to GCs. The level of cellular stress, immune activation status, or the cell cycle phase may be crucial for determining GC sensitivity and GC responsiveness as well as subcellular localization of the GR and GR levels. Central to the development of new drugs that target GR signaling alone or as add-on therapies, is an in-depth understanding of the molecular mechanisms of GC-independent GR desensitization, priming and activation of the unliganded GR, as well as synergy and cross-talk with other signaling pathways. This review will discuss the information currently available on these topics and their relevance to immunotherapy, as well as identify unanswered questions and future areas of research.

Glucocorticoid receptor isoforms direct distinct mitochondrial programs to regulate ATP production

The glucocorticoid receptor (GR), a nuclear receptor and major drug target, has a highly conserved minor splice variant, GRγ, which differs by a single arginine within the DNA binding domain. GRγ, which comprises 10% of all GR transcripts, is constitutively expressed and tightly conserved through mammalian evolution, suggesting an important non-redundant role. However, to date no specific role for GRγ has been reported. We discovered significant differences in subcellular localisation, and nuclear-cytoplasmic shuttling in response to ligand. In addition the GRγ transcriptome and protein interactome was distinct, and with a gene ontology signal for mitochondrial regulation which was confirmed using Seahorse technology. We propose that evolutionary conservation of the single additional arginine in GRγ is driven by a distinct, non-redundant functional profile, including regulation of mitochondrial function.

Haploinsufficiency for NR3C1, the gene encoding the glucocorticoid receptor, in blastic plasmacytoid dendritic cell neoplasms

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressive leukemia for which knowledge on disease mechanisms and effective therapies are currently lacking. Only a handful of recurring genetic mutations have been identified and none is specific to BPDCN. In this study, through molecular cloning in an index case that presented a balanced t(3;5)(q21;q31) and molecular cytogenetic analyses in a further 46 cases, we identify monoallelic deletion of NR3C1 (5q31), encoding the glucocorticoid receptor (GCR), in 13 of 47 (28%) BPDCN patients. Targeted deep sequencing in 36 BPDCN cases, including 10 with NR3C1 deletion, did not reveal NR3C1 point mutations or indels. Haploinsufficiency for NR3C1 defined a subset of BPDCN with lowered GCR expression and extremely poor overall survival (P = .0006). Consistent with a role for GCR in tumor suppression, functional analyses coupled with gene expression profiling identified corticoresistance and loss-of-EZH2 function as major downstream consequences of NR3C1 deletion in BPDCN. Subsequently, more detailed analyses of the t(3;5)(q21;q31) revealed fusion of NR3C1 to a long noncoding RNA (lncRNA) gene (lincRNA-3q) that encodes a novel, nuclear, noncoding RNA involved in the regulation of leukemia stem cell programs and G1/S transition, via E2F. Overexpression of lincRNA-3q was a consistent feature of malignant cells and could be abrogated by bromodomain and extraterminal domain (BET) protein inhibition. Taken together, this work points to NR3C1 as a haploinsufficient tumor suppressor in a subset of BPDCN and identifies BET inhibition, acting at least partially via lncRNA blockade, as a novel treatment option in BPDCN.

Glucocorticoid receptors in lung cancer: new perspectives

Proper expression of the glucocorticoid receptor (GR) plays an essential role in the development of the lung. GR expression and signalling in the lung is manipulated by administration of synthetic glucocorticoids (Gcs) for the treatment of neonatal, childhood and adult lung diseases. In lung cancers, Gcs are also commonly used as co-treatment during chemotherapy. This review summarises the effect of Gc monotherapy and co-therapy on lung cancers in vitro, in mouse models of lung cancer, in xenograft, ex vivo and in vivo The disparity between the effects of pre-clinical and in vivo Gc therapy is commented on in light of the recent discovery of GR as a novel tumour suppressor gene.

Regulation of steroid hormone receptors and coregulators during the cell cycle highlights potential novel function in addition to roles as transcription factors

Cell cycle progression is tightly controlled by several kinase families including Cyclin-Dependent Kinases, Polo-Like Kinases, and Aurora Kinases. A large amount of data show that steroid hormone receptors and various components of the cell cycle, including cell cycle regulated kinases, interact, and this often results in altered transcriptional activity of the receptor. Furthermore, steroid hormones, through their receptors, can also regulate the transcriptional expression of genes that are required for cell cycle regulation. However, emerging data suggest that steroid hormone receptors may have roles in cell cycle progression independent of their transcriptional activity. The following is a review of how steroid receptors and their coregulators can regulate or be regulated by the cell cycle machinery, with a particular focus on roles independent of transcription in G2/M.

Overexpression of GRß in colonic mucosal cell line partly reflects altered gene expression in colonic mucosa of patients with inflammatory bowel disease

The glucocorticoid receptor (GR) plays a crucial role in inflammatory responses. GR has several isoforms, of which the most deeply studied are the GRα and GRß. Recently it has been suggested that in addition to its negative dominant effect on GRα, the GRß may have a GRα-independent transcriptional activity. The GRß isoform was found to be frequently overexpressed in various autoimmune diseases, including inflammatory bowel disease (IBD). In this study, we wished to test whether the gene expression profile found in a GRß overexpressing intestinal cell line (Caco-2GRß) might mimic the gene expression alterations found in patients with IBD. Whole genome microarray analysis was performed in both normal and GRß overexpressing Caco-2 cell lines with and without dexamethasone treatment. IBD-related genes were identified from a meta-analysis of 245 microarrays available in online microarray deposits performed on intestinal mucosa samples from patients with IBD and healthy individuals. The differentially expressed genes were further studied using in silico pathway analysis. Overexpression of GRß altered a large proportion of genes that were not regulated by dexamethasone suggesting that GRß may have a GRα-independent role in the regulation of gene expression. About 10% of genes differentially expressed in colonic mucosa samples from IBD patients compared to normal subjects were also detected in Caco-2 GRß intestinal cell line. Common genes are involved in cell adhesion and cell proliferation. Overexpression of GRß in intestinal cells may affect appropriate mucosal repair and intact barrier function. The proposed novel role of GRß in intestinal epithelium warrants further studies.

Towards the emerging crosstalk: ERBB family and steroid hormones

Growth factors acting through receptor tyrosine kinases (RTKs) of ERBB family, along with steroid hormones (SH) acting through nuclear receptors (NRs), are critical signalling mediators of cellular processes. Deregulations of ERBB and steroid hormone receptors are responsible for several diseases, including cancer, thus demonstrating the central role played by both systems. This review will summarize and shed light on an emerging crosstalk between these two important receptor families. How this mutual crosstalk is attained, such as through extensive genomic and non-genomic interactions, will be addressed. In light of recent studies, we will describe how steroid hormones are able to fine-tune ERBB feedback loops, thus impacting on cellular output and providing a new key for understanding the complexity of biological processes in physiological or pathological conditions. In our understanding, the interactions between steroid hormones and RTKs deserve further attention. A system biology approach and advanced technologies for the analysis of RTK-SH crosstalk could lead to major advancements in molecular medicine, providing the basis for new routes of pharmacological intervention in several diseases, including cancer.