Update on the therapeutic significance of estrogen receptor beta in malignant gliomas

Deciphering Glioblastoma: Fundamental and Novel Insights into the Biology and Therapeutic Strategies of Gliomas

Gliomas constitute a diverse and complex array of tumors within the central nervous system (CNS), characterized by a wide range of prognostic outcomes and responses to therapeutic interventions. This literature review endeavors to conduct a thorough investigation of gliomas, with a particular emphasis on glioblastoma (GBM), beginning with their classification and epidemiological characteristics, evaluating their relative importance within the CNS tumor spectrum. We examine the immunological context of gliomas, unveiling the intricate immune environment and its ramifications for disease progression and therapeutic strategies. Moreover, we accentuate critical developments in understanding tumor behavior, focusing on recent research breakthroughs in treatment responses and the elucidation of cellular signaling pathways. Analyzing the most novel transcriptomic studies, we investigate the variations in gene expression patterns in glioma cells, assessing the prognostic and therapeutic implications of these genetic alterations. Furthermore, the role of epigenetic modifications in the pathogenesis of gliomas is underscored, suggesting that such changes are fundamental to tumor evolution and possible therapeutic advancements. In the end, this comparative oncological analysis situates GBM within the wider context of neoplasms, delineating both distinct and shared characteristics with other types of tumors.

Estrogen Receptors as Molecular Targets of Endocrine Therapy for Glioblastoma

Hormonal factors may participate in the development and progression of glioblastoma, the most aggressive primary tumor of the central nervous system. Many studies have been conducted on the possible involvement of estrogen receptors (ERs) in gliomas. Since there is a tendency for a reduced expression of ERs as the degree of malignancy of such tumors increases, it is important to understand the role of these receptors in the progression and treatment of this disease. ERs belong to the family of nuclear receptors, although they can also be in the plasmatic membrane, cytoplasm and mitochondria. They are classified as estrogen receptors alpha and beta (ER⍺ and ERβ), each with different isoforms that have a distinct function in the organism. ERs regulate multiple physiological and pathological processes through the activation of genomic and nongenomic pathways in the cell. Nevertheless, the role of each isoform in the development and progression of glioblastoma is not completely clear. Diverse in vitro and in vivo studies have shown encouraging results for endocrine therapy as a treatment for gliomas. At the same time, many questions have arisen concerning the nature of ERs as well as the mechanism of action of the proposed drugs. Hence, the aim of the current review is to describe the drugs that could possibly be utilized in endocrine therapy for the treatment of high-grade gliomas, analyze their interaction with ERs, and explore the involvement of these drugs and receptors in resistance to standard chemotherapy.

Prognostic Significance of Estrogen Receptor Alpha in Oral Squamous Cell Carcinoma

Simple Summary

Although the survival rate has improved over the past decades, the prognosis of oral squamous cell carcinoma (OSCC) is still poor, and new treatment strategies are required. The aim of this study was to evaluate estrogen receptor alpha (ERα) expression in OSCC in a large patient cohort as a potential prognostic marker and therapeutic target. The findings indicated a rare expression of ERα that, however, was associated with a dramatic decrease of overall survival in male patients. In ERα-positive OSCC patients, an ER-based therapeutic (adjuvant) approach in the future might be conceivable based on the findings of this study.

Abstract

Introduction: Several studies suggest an estrogen receptor alpha (ERα)-mediated influence on the pathogenesis of oral squamous cell carcinoma (OSCC), as described for other malignancies that are not considered to be primarily hormone-dependent. Recently, an association between ERα expression and improved survival in oropharyngeal squamous cell carcinoma (OPSCC) has been found. However, the prognostic relevance of ERα in OSCC has not been proven to date. Therefore, the aim of this study was to evaluate ERα expression in OSCC in a large patient cohort and analyze its influence on survival and recurrence. Material and Methods: A total of 316 patients with primary OSCC who received initial surgical therapy were included in this analysis. The expression of ERα was evaluated on tissue microarrays by immunohistochemistry in the primary tumor and/or primary lymph node metastases. The expression level was quantified by light microscopy using the immunoreactive score (IRS) for estrogen receptor detection. An IRS equal to or greater than 2 was considered positive. The 5-year overall survival (OS) and relapse-free survival (RFS) were examined by the Kaplan–Meier method and log-rank test. Results: A total of 316 patients (111 females; 205 males) with a mean age of 61.3 years (range 27–96 years) were included in this study. In 16 patients (5.1%; 6 females and 10 males), positive ERα expression was found in the primary tumor (n = 11; 11/302) or lymph node metastases (n = 5; 5/52). Patients with positive ERα expression in primary tumors/primary lymph node metastases had a significantly lower OS and RFS (p = 0.012; p = 0.0053) compared to ERα-negative patients. Sub-group analysis in relation to gender revealed a highly significant influence of ERα expression on OS and RFS in males but not in females, both for the ERα-positive primary tumor cohort (males: p = 0.0013; p < 0.0001; females: p = 0.56; p = 0.89) and the ERα-positive primary tumor/primary lymph node metastasis cohort (males: p < 0.0001; p < 0.0001; females: p = 0.95; p = 0.96). In multivariate cox regression analysis, the ERα IRS of primary tumors (dichotomized; ERα+ vs. ERα−) was an independent risk factor for OS (HR = 4.230; 95%CI 1.616–11.076; p = 0.003) and RFS (HR = 12.390; 95%CI 4.073–37.693; p < 0.001) in the male cohort. There was a significant difference (p = 0.006) of ERα positivity with regard to the localization of the primary tumor. ERα positivity in the primary tumor was significantly associated (p = 0.026) with UICC stage, with most of the cases being diagnosed in stage IV. Furthermore, there was a significantly (p = 0.049) higher rate of bone infiltration in ERα-positive patients. Conclusion: Expression of ERα is rare in OSCC; however, it is associated with a dramatic decrease in OS in male patients. Further studies are necessary to confirm our results and to evaluate the exact mechanism underlying this observation. Hence, ERα-positive OSCC patients might benefit from an ER-based therapeutic (adjuvant) approach in the future.

The aryl hydrocarbon receptor: A diagnostic and therapeutic target in glioma

Glioblastoma multiforme (GBM) is a deadly disease; 5-year survival rates have shown little improvement over the past 30 years. In vivo positron emission tomography (PET) imaging is an important method of identifying potential diagnostic and therapeutic molecular targets non-invasively. The aryl hydrocarbon receptor (AhR) is a transcription factor that regulates multiple genes involved in immune response modulation and tumorigenesis. The AhR is an attractive potential drug target and studies have shown that its activation by small molecules can modulate innate and adaptive immunity beneficially and prevent AhR-mediated tumour promotion in several cancer types. In this review, we provide an overview of the role of the AhR in glioma tumorigenesis and highlight its potential as an emerging biomarker for glioma therapies targeting the tumour immune response and PET diagnostics.

Targeting Several Biologically Reported Targets of Glioblastoma Multiforme by Assaying 2D and 3D Cultured Cells

Glioblastoma multiforme (GBM) is account for 70% of all primary malignancies of the central nervous system. The median survival of human patients after treatment is around 15 months. There are several biological targets which have been reported that can be pursued using ligands with varied structures to treat this disease. In our group, we have developed several ligands that target a wide range of proteins involved in anticancer effects, such as histone deacetylase (HDACs), G protein-coupled estrogen receptor 1 (GPER), estrogen receptor-beta (ERβ) and NADPH oxidase (NOX), that were screened on bidimensional (2D) and tridimensional (3D) GBM stem cells like (GSC). Our results show that some HDAC inhibitors show antiproliferative properties at 21-32 µM. These results suggest that in this 3D culture, HDACs could be the most relevant targets that are modulated to induce the antiproliferative effects that require in the future further experimental studies.

Tumour suppression through modulation of neprilysin signaling: A comprehensive review

Peptidases are emerging as promising drug targets in tumour suppression. Neprilysin, also known as neutral endopeptidase, is a cell surface peptidase that degrades various peptides such as angiotensin II, endothelin I, Substance P, etc., and reduces their local concentration. Neprilysin is expressed in various tissues such as kidney, prostate, lung, breast, brain, intestine, adrenal gland, etc. The tumour-suppressor mechanisms of neprilysin include its peptidase activity that degrades mitogenic growth factors such as fibroblast growth factor-2 and insulin-like growth factors, and the protein-protein interaction of neprilysin with phosphatase and tensin homolog, focal adhesion kinase, ezrin/radixin/moesin, and phosphoinositide 3-kinase. Studies have shown that the levels of neprilysin play an important role in malignancies. NEP is downregulated in prostate, renal, lung, breast, urothelial, cervical, hepatic cancers, etc. Histone deacetylation and hypermethylation of the neprilysin promoter region are the common mechanisms involved in the downregulation of neprilysin. Downregulation of the peptidase promotes angiogenesis, cell survival and cell migration. This review presents an overview of the role of neprilysin in malignancy, the tumour suppression mechanisms of neprilysin, the epigenetic mechanisms responsible for downregulation of neprilysin, and the potential pharmacological approaches to upregulate neprilysin levels and its activity.

Does tamoxifen have a therapeutic role outside of breast cancer? A systematic review of the evidence

INTRODUCTION

Tamoxifen is a widely used hormonal based therapy for breast cancer in the adjuvant and metastatic setting, prolonging overall and recurrence-free survival. There has been increasing interest in the potential for novel "off-target" effects of tamoxifen and its metabolite N-desmethyltamoxifen across a number of cancer types. We aim to review the current literature regarding the potential use of tamoxifen in other primary malignancies.

METHOD

A qualitative systematic review was performed according to the PRISMA guidelines using pre-set search criteria across the PubMed, Cochrane and Scopus databases from 1985 to 2019. Additional results were generated from included papers references.

RESULTS

A total of 324 papers were identified, of which 47 were included; a further 29 articles were obtained from additional referencing to give a total of 76 articles. Clinical trials have demonstrated benefits with the use of tamoxifen in isolation and combination, specifically in patients with advanced non-resectable malignancy, however results are not consistent across the literature. In vivo data consistently suggests that off target effects of tamoxifen are mediated through the ceramide pathway or through inhibition of protein kinase C (PKC).

CONCLUSIONS

With increased focus upon the potential of repurposing drugs, tamoxifen may be a candidate for repurposing in the wider cancer setting. There is evidence to suggest that the ceramide or PKC pathway could act as a therapeutic target for tamoxifen or alternative chemotherapeutics and merits further investigation.

Detection of Six β-Agonists by Three Multiresidue Immunosensors Based on an Anti-bovine Serum Albumin-Ractopamine-Clenbuterol-Salbutamol Antibody

According to an indirect competitive immunoassay, six β-agonists (clenbuterol (CL), salbutamol (SAL), ractopamine (RAC), terbutaline (TER), mabuterol (MAB), and tulobuterol (TUL)) were detected by three novel multiresidue immunosensors on the basis of the successful preparation of bovine serum albumin (BSA)-RAC-CL-SAL multideterminant antigen and anti-BSA-RAC-CL-SAL antibody. A new strategy was reported to detect six β-agonists by combining nanotechnology, electrochemical detection, and specific immune technology. At the same concentration, the amperometric response for detection of six β-agonists was in a sequence of GCE/GNP/SAL > GCE/GNP/RAC > GCE/GNP/CL. Detection limits of six β-agonists show that the multiresidue detection performance of the GCE/GNP/RAC immunosensor is better than those of GCE/GNP/SAL and GCE/GNP/CL immunosensors. Three immunosensors manifest superior properties with a wide linear range, low detection limit, excellent reproducibility, and stability. The proposed GCE/GNP/RAC immunosensor displays high accuracy and can be effectively used for real sample detection.

Estrogen Receptor Expression in Glial Tumors of Iranian Patients: A Single Center Experience

Background & Objective

Gliomas are the most common type of primary intracranial tumors in adults. The expression of estrogen receptors varies in different grades of glial tumors, and some studies have suggested that this expression might have a prognostic value. It seems that estrogen receptor expression negatively correlates with the histological grade of gliomas. In the present study, we aimed to determine the expression of estrogen receptor in different glial tumors in Iranian patients and to find a possible correlation between its expression and the grade of glial tumors.

Methods

The brain tumors pathology reports from 2014 to 2017 in the Pathology Department of Shohaday-e Tajrish Hospital in Tehran, Iran were evaluated and 104 different gliomas: 79 cases of astrocytoma and 25 cases of oligodendroglioma were selected. All the samples were re-evaluated by a neuropathologist in order to accurately determine the tumor grade. The immunohistochemistry was carried out to detect the expression of estrogen receptor alpha and beta on brain tumors.

Results

None of the samples expressed estrogen receptor alpha. In the case of estrogen receptor beta (ERβ), all samples showed various degrees of positivity: 9% weak, 40% moderate, and 51% strong expressions. The level of ERβ expression was found to be conversely correlated with tumor grade.

Conclusion

Our study demonstrated that ERβ is expressed in the majority (if not all) of the glial tumors and its expression was conversely related to the tumor grade. Because of well-tolerability and acceptable adverse effects, ER agonists might be considered as therapeutic agents for the patients with glial tumors.

Bazedoxifene enhances paclitaxel efficacy to suppress glioblastoma via altering Hippo/YAP pathway

Glioblastoma multiform (GBM) is an aggressive type of brain tumor originated from astrocytes. Owing to the limited therapeutic options, intensive efforts are still being made to find novel treatments for GBM. In this study, we first identified that bazedoxifene bore the ability to reduce cell survival and cell invasion of glioblastoma cells. Furthermore, our results also revealed that bazedoxifene combining with paclitaxel had better efficacy to suppress glioblastoma progression by promoting apoptosis and reducing EMT. Combination of bazedoxifene and paclitaxel also accelerated YAP phosphorylation and inactivation. Importantly, preclinical animal model also verified our in vitro findings. Together, our data not only define the underlying mechanism responsible for action of bazedoxifene on glioblastoma cells but also build strong rational to develop bazedoxifene for the treatment of GBM patients.

Knockdown of estrogen receptor β increases proliferation and affects the transcriptome of endometrial adenocarcinoma cells

Background

Estrogen receptor β (ERβ) has been repeatedly suggested to play important roles in hormone-dependent cancer like in tumors of the breast, ovary or prostate. In this study, we intended to further elucidate its role in endometrial cancer.

Methods

For this purpose, we knocked down ERβ expression in two endometrial cancer cell lines, the ERα-negative/ERβ-positive line HEC-1A and the ERα/β-positive cell line RL95/2, by means of siRNA transfection. Cell proliferation after transfection was assessed using the fluorescent CTB Assay (Promega). In order to elucidate possible molecular mechanisms which might underlie the effect on proliferation, we performed transcriptome analyses by means of human Affymetrix Human Gene Chip 2.0. Additionally, we treated the employed cell lines with different ERβ modulators to examine their effect on proliferation.

Results

siRNA-mediated knockdown of ERβ significantly increased proliferation of both endometrial cancer cell lines. In HEC-1A cells, proliferation was significantly increased 4, 5 and 6 days after transfection, with a maximum of about 1.7-fold (p < 0.05) on day 6. Endometrial RL95/2 cells with an ERβ knockdown exhibited a clearly enhanced proliferation on day 3 and days 4 to 8, when even 2.4-fold higher numbers of viable cells were detected (p < 0.01). Transcriptome analysis revealed that this was accompanied by increased expression of several genes being known to be upregulated in cancer, including proliferation-associated genes and oncogenes, and by repression of genes associated with differentiation, apoptosis or growth inhibition. Corroborating the observed knockdown effects, treatment with the ERβ antagonists PHTTP and (R, R) THC was also able to induce proliferation of both cell lines.

Conclusions

Our data clearly support the putative role of ERβ as tumor suppressor in endometrium as previously suggested in studies on other tissues and encourage further studies to find out to what extent this molecule might be a potential therapy target in this cancer entity.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5928-2) contains supplementary material, which is available to authorized users.

Evaluation of estrogen receptor expression in low-grade and high-grade astrocytomas

OBJECTIVE

This study aims to compare estrogen receptor expression between low and high-grade astrocytomas.

METHOD

A study using paraffin blocks of glial tumors from the Anatomy Pathology archives of São Marcos Hospital was carried out and began after approval by the Review Board of the Federal University of Piaui. Specimens were histochemically marked with an anti-ER alpha antibody. Brown-stained nuclei were considered positive, regardless of reaction intensity. Data were statistically analyzed using the Mann-Whitney test and Spearman's correlation. Statistical significance was established at p<0.05.

RESULTS

The mean percentage of nuclei stained with anti-ER alpha in low-and high-grade astrocytomas was 0.04 and zero, respectively, while Spearman's correlation showed a strong negative association between low and high-grade tumors (p<0.001) and (r= -0.67), respectively.

CONCLUSION

In the current study, estrogen receptor expression was positive only in low-grade astrocytomas and nil in high-grade astrocytomas, showing that ER expression declines with the grade of tumor malignancy.

A lateral flow immunochromatographic strip test for rapid detection of hexoestrol in fish samples

A lateral flow immunochromatographic strip test was developed for rapid and sensitive on-site detection of hexoestrol (HES) residues in fish samples with colloidal gold labelling of the anti-HES monoclonal antibody. The strip is composed of a sample pad, a conjugate reagent pad, an absorbent pad and a test membrane containing a control line and a test line. The sensitivity (half inhibitory concentration, IC50) of the strip in the detection of fish extract samples was confirmed to be 1.86 µg kg-1, and the limit of detection value was 0.62 µg kg-1. For intra-assay and inter-assay reproducibility, recoveries of HES-spiked samples ranged from 86.3% to 92.3% and 85.8% to 93.4%, coefficients of variation were 2.91-4.64% and 4.24-5.17%, respectively. High-performance liquid chromatography was employed to confirm the performance of the strip. The strip test takes less than 10 min, and thus provides a repaid method for on-site detection of HES residues.