Differential expression of glucocorticoid receptor in carcinomas of the human digestive system

Immunohistochemical localization of glucocorticoid receptors in the human cochlea

In the present study we investigated the localization of glucocorticoid receptors (GCR) in the human inner ear using immunohistochemistry. Celloidin-embedded cochlear sections of patients with normal hearing (n = 5), patients diagnosed with MD (n = 5), and noise induced hearing loss (n = 5) were immunostained using GCR rabbit affinity-purified polyclonal antibodies and secondary fluorescent or HRP labeled antibodies. Digital fluorescent images were acquired using a light sheet laser confocal microscope. In celloidin-embedded sections GCR-IF was present in the cell nuclei of hair cells and supporting cells of the organ of Corti. GCR-IF was detected in cell nuclei of the Reisner's membrane. GCR-IF was seen in cell nuclei of the stria vascularis and the spiral ligament. GCR-IF was found in the spiral ganglia cell nuclei, however, spiral ganglia neurons showed no GCR-IF. Although GCRs were found in most cell nuclei of the cochlea, the intensity of IF was differential among the different cell types being more intense in supporting cells than in sensory hair cells. The differential expression of GCR receptors found in the human cochlea may help to understand the site of action of glucocorticoids in different ear diseases.

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.

Therapeutic targeting of pancreatic cancer stem cells by dexamethasone modulation of the MKP-1-JNK axis

Postoperative recurrence from microscopic residual disease must be prevented to cure intractable cancers, including pancreatic cancer. Key to this goal is the elimination of cancer stem cells (CSCs) endowed with tumor-initiating capacity and drug resistance. However, current therapeutic strategies capable of accomplishing this are insufficient. Using in vitro models of CSCs and in vivo models of tumor initiation in which CSCs give rise to xenograft tumors, we show that dexamethasone induces expression of MKP-1, a MAPK phosphatase, via glucocorticoid receptor activation, thereby inactivating JNK, which is required for self-renewal and tumor initiation by pancreatic CSCs as well as for their expression of survivin, an anti-apoptotic protein implicated in multidrug resistance. We also demonstrate that systemic administration of clinically relevant doses of dexamethasone together with gemcitabine prevents tumor formation by CSCs in a pancreatic cancer xenograft model. Our study thus provides preclinical evidence for the efficacy of dexamethasone as an adjuvant therapy to prevent postoperative recurrence in patients with pancreatic cancer.

Coordinate expression loss of GKN1 and GKN2 in gastric cancer via impairment of a glucocorticoid-responsive enhancer

Gastrokines (GKNs) are anti-inflammatory proteins secreted by gastric epithelial (surface mucous and pit) cells, with their aberrant loss of expression causally linked to premalignant inflammation and gastric cancer (GC). Transcriptional mechanisms accounting for GKN expression loss have not been elucidated. Using human clinical cohorts, mouse transgenics, bioinformatics, and transfection/reporter assays, we report a novel mechanism of GKN gene transcriptional regulation and its impairment in GC. GKN1/GKN2 loss is highly coordinated, with both genes showing parallel downregulation during human and mouse GC development, suggesting joint transcriptional control. In BAC transgenic studies, we defined a 152-kb genomic region surrounding the human GKN1/GKN2 genes sufficient to direct their tissue- and lineage-restricted expression. A screen of the 152-kb region for candidate regulatory elements identified a DNase I hypersensitive site (CR2) located 4 kb upstream of the GKN1 gene. CR2 showed overlapping enrichment of enhancer-related histone marks (H3K27Ac), a consensus binding site (GRE) for the glucocorticoid receptor (GR), strong GR occupancy in ChIP-seq data sets and, critically, exhibited dexamethasone-sensitive enhancer activity in reporter assays. Strikingly, GR showed progressive expression loss, paralleling that of GKN1/2, in human and mouse GC, suggesting desensitized glucocorticoid signaling as a mechanism underlying GKN loss. Finally, mouse adrenalectomy studies revealed a critical role for endogenous glucocorticoids in sustaining correct expression (and anti-inflammatory restraint) of GKNs in vivo. Together, these data link the coordinate expression of GKNs to a glucocorticoid-responsive and likely shared transcriptional enhancer mechanism, with its compromised activation contributing to dual GKN loss during GC progression.NEW & NOTEWORTHY Gastrokine 2 (GKN2) is an anti-inflammatory protein produced by the gastric epithelium. GKN2 expression is progressively lost during gastric cancer (GC), which is believed to play a casual role in GC development. Here, we use bacterial artificial chromosome transgenic studies to identify a glucocorticoid-responsive enhancer element that likely governs expression of GKN1/GKN2, which, via parallel expression loss of the anti-inflammatory glucocorticoid receptor, reveals a novel mechanism to explain the loss of GKN2 during GC pathogenesis.

GR, Sgk1, and NDRG1 in esophageal squamous cell carcinoma: their correlation with therapeutic outcome of neoadjuvant chemotherapy

Background

Esophageal squamous cell carcinoma (ESCC) is a highly malignant neoplasm.

The glucocorticoid (GC)-glucocorticoid receptor (GR) pathway plays pivotal roles in cellular response to various stresses of tumor cells, including chemotherapy. However, the status of the GC-GR pathway in ESCC, including its correlation with chemotherapeutic responses, is largely unknown.

Methods

GR, serum-and glucocorticoid-regulated kinase 1 (Sgk1), and N-myc down regulation gene 1 (NDRG1) were immunolocalized in 98 patients with ESCC who had undergone esophagectomy following neoadjuvant chemotherapy (NAC) with 2 courses of 5-fluorouracil + cisplatin. We also examined biopsy specimens before NAC in 42 cases and compared the results between those before and after NAC.

Results

Overall survival (OS) of the patients treated with surgery following NAC was significantly shorter in the group with high GR than that with low GR status (P = 0.0473). Both OS and disease-free survival (DFS) were significantly shorter in both Sgk1- and NDRG1-high groups than in the low groups (OS: Sgk1, P = 0.0055; NDRG1, P = 0.0021; DFS: Sgk1, P = 0.0240; NDRG1, P = 0.0086). Biopsy specimens before NAC showed significantly shorter DFS in the high Sgk1 group (P = 0.0095), while both OS and DFS were shorter in the high NDRG1 group (OS, P = 0.0233; DFS, P = 0.0006) than in the respective low groups. In the high NDRG1 group of biopsy specimens before NAC, the tumor reduction rate by NAC was significantly attenuated (P = 0.021).

Conclusions

High GR, Sgk1, and NDRG1 statuses in ESCC after NAC was significantly associated with an overall worse prognosis, with no significant changes in their expression levels before and after NAC. Therefore, increased activity of the GC-GR pathway with enhanced induction of Sgk1 and NDRG1 in carcinoma cells play pivotal roles in tumor progression and development of chemo-resistance in patients with ESCC undergoing NAC.

Endogenous glucocorticoids prevent gastric metaplasia by suppressing spontaneous inflammation

In the stomach, chronic inflammation causes metaplasia and creates a favorable environment for the evolution of gastric cancer. Glucocorticoids are steroid hormones that repress proinflammatory stimuli, but their role in the stomach is unknown. In this study, we show that endogenous glucocorticoids are required to maintain gastric homeostasis. Removal of circulating glucocorticoids in mice by adrenalectomy resulted in the rapid onset of spontaneous gastric inflammation, oxyntic atrophy, and spasmolytic polypeptide-expressing metaplasia (SPEM), a putative precursor of gastric cancer. SPEM and oxyntic atrophy occurred independently of lymphocytes. However, depletion of monocytes and macrophages by clodronate treatment or inhibition of gastric monocyte infiltration using the Cx3cr1 knockout mouse model prevented SPEM development. Our results highlight the requirement for endogenous glucocorticoid signaling within the stomach to prevent spontaneous gastric inflammation and metaplasia, and suggest that glucocorticoid deficiency may lead to gastric cancer development.

Glucocorticoid receptor expression in 20 solid tumor types using immunohistochemistry assay

Background

Glucocorticoid receptor (GR) activity plays a role in many aspects of human physiology and may play a crucial role in chemotherapy resistance in a wide variety of solid tumors. A novel immunohistochemistry (IHC) based assay has been previously developed and validated in order to assess GR immunoreactivity in triple-negative breast cancer. The current study investigates the standardized use of this validated assay to assess GR expression in a broad range of solid tumor malignancies.

Methods

Archived formalin-fixed paraffin-embedded tumor bank samples (n=236) from 20 different solid tumor types were analyzed immunohistochemically. Nuclear staining was reported based on the H-score method using differential intensity scores (0, 1+, 2+, or 3+) with the percent stained (out of at least 100 carcinoma cells) recorded at each intensity.

Results

GR was expressed in all tumor types that had been evaluated. Renal cell carcinoma, sarcoma, cervical cancer, and melanoma were those with the highest mean H-scores, indicating high levels of GR expression. Colon, endometrial, and gastric cancers had lower GR staining percentages and intensities, resulting in the lowest mean H-scores.

Conclusion

A validated IHC assay revealed GR immunoreactivity in all solid tumor types studied and allowed for standardized comparison of reactivity among the different malignancies.

Impact

Baseline expression levels of GR may be a useful biomarker when pharmaceutically targeting GR in research or clinical setting.

Dexamethasone induces docetaxel and cisplatin resistance partially through up-regulating Krüppel-like factor 5 in triple-negative breast cancer

PURPOSE

Dexamethasone (Dex), a glucocorticoid (GC), is used as a pretreatment drug in cancer patients undergoing chemotherapy. Dex functions by binding to the glucocorticoid receptor (GR) to prevent allergic reactions and severe chemotherapeutic side effects such as nausea and vomiting. However, the mechanisms by which Dex causes chemoresistance remain unknown.

METHODS

We used docetaxel and cisplatin to treat triple-negative breast cancer (TNBC) cells with or without Dex and assessed cell proliferation using a sulforhodamine B colorimetric (SRB) assay. Additionally, Western blotting was employed to measure Krüppel-like factor 5 (KLF5), GR and several apoptosis-related proteins. To determine how the GR regulates KLF5, we used qRT-PCR, luciferase reporter assays and ChIP assays. Finally, we detected the involvement of Dex in TNBC chemotherapeutic resistance using HCC1806 xenograft model in vivo.

RESULTS

In this study, we demonstrated that Dex induces docetaxel and cisplatin resistance in TNBC cells in vitro and in vivo. Dex up-regulates pro-survival transcription factor KLF5 expression at both mRNA and protein levels dependent on GR. Importantly, Dex failed to promote cancer cell survival and tumor growth when KLF5 induction was blocked.

CONCLUSIONS

We conclude that KLF5 is a Dex-induced gene that contributes to Dex-mediated drug chemoresistance, providing a potential novel target for TNBC treatment.

Development and validation of an immunohistochemistry assay to assess glucocorticoid receptor expression for clinical trials of mifepristone in breast cancer

BACKGROUND

Glucocorticoid receptor (GR) activity has been associated with chemotherapy resistance and poor outcomes in patients with triple negative breast cancer (TNBC). The aim of this study was to develop an immunohistochemistry (IHC) assay to assess GR expression in archival formalin-fixed, paraffin-embedded human invasive breast carcinoma samples.

METHODS

An optimized GR assay protocol was developed using rabbit monoclonal antibody to GR clone D8H2. Precision and reproducibility of the GR IHC assay was determined by conducting multiple staining runs of four invasive breast carcinoma samples using replicate serial sections. Assay sensitivity was examined in 50 TNBC samples (>10 mm) obtained from a tumor bank, and 43 paired TNBC samples from a tissue microarray (TMA) (1.5 mm). GR positivity was assessed using a percent scoring approach with a ≥10% cutoff for nuclear staining of tumor cells at any intensity. Analysis of the paired TMA cores was performed by averaging the scores of the two cores for each case.

RESULTS

Equivalent cellular patterns of GR reactivity were observed in all replicates from the multiple staining runs; coefficients of variation did not exceed 4.7% for average H-scores greater than 3.4, thus meeting the criteria for assay precision and reproducibility (coefficient of variation ≤20%). GR expression in TNBC single-tissue samples and TMA cores was characterized as mostly nuclear, with some concurrent cytoplasmic reactivity. Eighty-four percent of the 49 evaluable TNBC samples and 60% of the 42 evaluable paired TMA samples were positive for GR expression.

CONCLUSION

A robust and reproducible GR IHC assay was successfully developed for use in invasive breast carcinoma tissues. Differences in GR expression between larger single tissues and smaller TMA cores illustrate the heterogeneity of the disease, as well as potential intra-tumoral heterogeneity. This assay is currently being utilized in clinical trials of mifepristone, a GR antagonist, in patients with TNBC.

Clustering nuclear receptors in liver regeneration identifies candidate modulators of hepatocyte proliferation and hepatocarcinoma

Background & Aims

Liver regeneration (LR) is a valuable model for studying mechanisms modulating hepatocyte proliferation. Nuclear receptors (NRs) are key players in the control of cellular functions, being ideal modulators of hepatic proliferation and carcinogenesis.

Methods & Results

We used a previously validated RT-qPCR platform to profile modifications in the expression of all 49 members of the NR superfamily in mouse liver during LR. Twenty-nine NR transcripts were significantly modified in their expression during LR, including fatty acid (peroxisome proliferator-activated receptors, PPARs) and oxysterol (liver X receptors, Lxrs) sensors, circadian masters RevErbα and RevErbβ, glucocorticoid receptor (Gr) and constitutive androxane receptor (Car). In order to detect the NRs that better characterize proliferative status vs. proliferating liver, we used the novel Random Forest (RF) analysis to selected a trio of down-regulated NRs (thyroid receptor alpha, Trα; farsenoid X receptor beta, Fxrβ; Pparδ) as best discriminators of the proliferating status. To validate our approach, we further studied PPARδ role in modulating hepatic proliferation. We first confirmed the suppression of PPARδ both in LR and human hepatocellular carcinoma at protein level, and then demonstrated that PPARδ agonist GW501516 reduces the proliferative potential of hepatoma cells.

Conclusions

Our data suggest that NR transcriptome is modulated in proliferating liver and is a source of biomarkers and bona fide pharmacological targets for the management of liver disease affecting hepatocyte proliferation.

Nuclear receptors in regenerating liver and hepatocellular carcinoma

A comprehensive understanding of the pathways underlying hepatocyte turnover and liver regeneration is essential for the development of innovative and effective therapies in the management of chronic liver disease, and the prevention of hepatocellular carcinoma (HCC) in cirrhosis. Nuclear receptors (NRs) are master transcriptional regulators of liver development, differentiation and function. NRs have been implicated in the modulation of hepatocyte priming and proliferation in regenerating liver, chronic hepatitis and HCC development. In this review, we focus on NRs and their pathways regulating hepatocyte proliferation and liver regeneration, with a perspective view on NRs as candidate biomarkers and novel pharmacological targets in the management of liver disease and HCC.

Glucocorticoid receptor-mediated transcriptional activation of S100P gene coding for cancer-related calcium-binding protein

S100P is a member of the S100 family of calcium-binding proteins involved in calcium sensing and signal transduction. Its abnormal expression and biological activities are linked to tumor phenotype, namely to increased survival, proliferation, invasion and metastatic propensity of tumor cells. Association of S100P with outcome of tumor treatment and preliminary data from S100P promoter analysis prompted us to study regulation of S100P expression by glucocorticoids, which are implicated in tumor response to chemotherapy. We showed that dexamethasone (DX), a representative glucocorticoid, was capable to induce activity of S100P promoter by means of increased expression, nuclear translocation, and transactivation properties of the glucocorticoid receptor (GR). Moreover, DX treatment led to decreased phosphorylation of ERK1/2, reduced transcriptional activity of AP1, and modulated activity of some additional transcription factors. We identified a promoter region responsible for DX-mediated transactivation and proved GR binding to S100P promoter. We found that the effect of DX was enhanced by partial but not complete inhibition of the MAPK/ERK pathway, supporting an active crosstalk between GR and MAPK/ERK signal transduction in control of S100P expression. On the other hand, suppression of GR mRNA level by transient siRNA expression resulted in reduced S100P transcription. The role of GR activation in S100P regulation was supported by co-expression of GR with S100P in cells treated with DX. These data suggest that S100P is a direct transcriptional target of glucocorticoid-mediated signaling in tumor cells that is activated through the interplay of GR and MAPK pathways.

Expression of the glucocorticoid receptor in renal cell neoplasms: an immunohistochemical and quantitative reverse transcriptase polymerase chain reaction study

Glucocorticoid receptors mediate the action of steroid hormones in a variety of tissues, including the kidney. Our goal was to determine the expression pattern and prognostic significance of glucocorticoid receptor in renal cell neoplasms. Paraffin-embedded microarrays from 200 patients with RCNs including 147 clear cell renal cell carcinomas, 23 papillary, 16 chromophobe renal cell carcinoma, and 14 oncocytomas were analyzed for glucocorticoid receptor expression by immunohistochemistry. Glucocorticoid receptor expression was also quantitated by real-time reverse transcriptase polymerase chain reaction in 45 cases (33 clear cell renal cell carcinomas, 5 chromophobe renal cell carcinomas, and 3 oncocytomas). Strong nuclear glucocorticoid receptor expression was present in normal glomeruli and in the proximal convoluted tubules. Nuclear glucocorticoid receptor expression was found in most clear cell renal cell carcinomas (66%), in 26% of papillary renal cell carcinomas, and in only 6% of chromophobe renal cell carcinomas and 14% of oncocytoma (P < .005). Within the clear cell renal cell carcinoma group, most positive cases (87%) demonstrated strong immunoreactivity (2+ and 3+), whereas only 1 papillary renal cell carcinoma, 1 chromophobe renal cell carcinoma, and none of the oncocytomas showed strong expression. Glucocorticoid receptor α messenger RNA expression was significantly higher in clear cell renal cell carcinoma than in chromophobe renal cell carcinoma, oncocytoma, or in the normal kidney. Significantly more frequent glucocorticoid receptor expression was associated with tumors of low nuclear grade (Fuhrman grade 1 and 2) and low stage (stages 1 and 2; P = .0068 and P = .0002). Survival analysis revealed a significant direct correlation between glucocorticoid receptor expression and overall survival in clear cell renal cell carcinoma (P = .01). In summary, strong glucocorticoid receptor expression was most commonly seen in clear cell renal cell carcinoma and only rarely seen in other subtypes. The glucocorticoid receptor expression pattern in RCNs seems to reflect the histogenetic origin of clear cell renal cell carcinoma from the proximal nephron. Finally, glucocorticoid receptor expression proved to be a marker of less aggressive behavior in clear cell renal cell carcinoma.

The relationship between the expression of the glucocorticoid receptor in biopsied colonic mucosa and the glucocorticoid responsiveness of ulcerative colitis patients

The objective of this study was to clarify the relationship between the frequency of infiltrating cells expressing the glucocorticoid receptors (GR) alpha and beta in biopsied colonic mucosa and the glucocorticoid (GC) responsiveness of ulcerative colitis (UC) patients. Active UC patients (n=38) were divided into GC-sensitive and GC-resistant groups. GRbeta(+) cells were significantly higher in the GC-resistant group than in the GC-sensitive and control groups. GRalpha mRNA was expressed in all UC patients, while GRbeta mRNA was expressed in only 1 patient in the GC-sensitive group (n=6) and 7 patients in the GC-resistant group (n=8). Double-positive cells for GRbeta and CD4 or CD19 were frequently observed. The Foxp3(+) cell count was significantly higher in the GC-sensitive group than in the GC-resistant group, but double Foxp3(+)GRbeta(+) cells were not observed. These results indicated that the sensitivity of GC therapy could probably be predicted by immunostaining biopsy specimens for GRbeta and Foxp3.

Mechanisms regulating the susceptibility of hematopoietic malignancies to glucocorticoid-induced apoptosis

Glucocorticoids (GCs) are commonly used in the treatment of hematopoietic malignancies owing to their ability to induce apoptosis of these cancerous cells. Whereas some types of lymphoma and leukemia respond well to this drug, others are resistant. Also, GC-resistance gradually develops upon repeated treatments ultimately leading to refractory relapsed disease. Understanding the mechanisms regulating GC-induced apoptosis is therefore uttermost important for designing novel treatment strategies that overcome GC-resistance. This review discusses updated data describing the complex regulation of the cell's susceptibility to apoptosis triggered by GCs. We address both the genomic and nongenomic effects involved in promoting the apoptotic signals as well as the resistance mechanisms opposing these signals. Eventually we address potential strategies of clinical relevance that sensitize GC-resistant lymphoma and leukemia cells to this drug. The major target is the nongenomic signal transduction machinery where the interplay between protein kinases determines the cell fate. Shifting the balance of the kinome towards a state where Glycogen synthase kinase 3alpha (GSK3alpha) is kept active, favors an apoptotic response. Accumulating data show that it is possible to therapeutically modulate GC-resistance in patients, thereby improving the response to GC therapy.

Glucocorticoid receptor expression in breast cancer associates with older patient age

Breast cancer can be classified according to estrogen (ER), progesterone (PR), and HER2 receptor expression. Recent evidence suggests that activation of the glucocorticoid receptor (GR) contributes to breast cell survival, although the incidence of GR expression in primary human breast tumors is not well established. We therefore evaluated ER, PR, HER2, and GR by immunohistochemistry from 231 patients and found that while African American (AA) patient tumors were much more likely to be ER negative compared to tumors from non-AA patients, GR expression was significantly higher in tumors from patients >or=50 regardless of ancestry. Prospective examination of GR expression in tumors should be considered to determine whether GR contributes to long-term clinical outcome.