Expression of estrogen and progesterone receptors in astrocytomas: a literature review

Unlocking estrogen receptor: Structural insights into agonists and antagonists for glioblastoma therapy

Glioblastoma (GBM), a malignant brain tumor originating in glial cells, is one of the most common primary brain malignancies, affecting one in 100,000 people, typically in the frontal lobe. Estrogens, like estradiol-17 (E2), significantly influence GBM progression, metastasis, and angiogenesis. Estrogen receptors (ERs) are crucial in signal transduction and physiology, making them potential therapeutic targets. However, their roles in GBM pathogenesis remain unclear. This review explores ERs in GBM, focusing on their involvement in tumor immune evasion, modulation of the tumor microenvironment, and the mechanisms underlying GBM progression. Additionally, therapeutic opportunities targeting ERs for GBM treatment are discussed. Estrogen, synthesized primarily in ovaries and in smaller amounts by adrenal glands and fat tissues, regulates reproductive systems, bone density, skin health, and cardiovascular function. The invasive nature and heterogeneity of GBM complicate therapy development. Preclinical findings suggest that endocrine therapy with hormone receptor agonists or antagonists can extend patient survival and improve post-treatment quality of life. The ERβ pathway, in particular, shows tumor-suppressive potential, limiting glioma progression with fewer side effects. ERβ agonists could become a novel drug class for GBM treatment. Identifying biomarkers and specific therapeutic targets is crucial for early detection and improved prognosis. Estrogen and its receptors are advantageous for GBM treatment due to their regulation of numerous biological processes, ability to penetrate the blood-brain barrier, and genomic and non-genomic control of transcription, making them promising targets for GBM therapy.

Disruption of neurosteroid synthesis and release by tris(2,3-dibromopropyl)isocyanurate in primary mouse cortical astrocytes in vitro

Neurosteroidogenesis in astrocytes is crucial for the proper development and functioning of the brain. During this process, key neurohormones such as progesterone (P4 ), testosterone (T), and estradiol (E2 ) are produced. Proper production and release of neurosteroids can be affected by substances referred to as endocrine-disrupting compounds (EDCs). Tris-(2,3-dibromopropyl)isocyanurate (TBC) is a representative of novel brominated flame retardants used to stop ignition or reduce fire-related property damage to plastics, polyolefin, polyphenyl alkene, unsaturated polyester, synthetic rubber, and fibers. Interestingly, previous studies have shown that TBC can enhance the proliferation of estradiol-sensitive breast cancers in vitro, which suggests that TBC has EDC properties. Therefore, given the suspected endocrine-disrupting properties of TBC, the aim of the present study was to determine the impact of TBC on the neurosteroid (P4 , T, and E2 ) production and secretion as well as the mRNA expression of key enzymes involved in its production in mouse astrocytes in vitro. Our paper shows that TBC increases P4 production with a strong decrease in T production, which is accompanied by a decrease in Cyp17a1 mRNA expression, that is, the main enzyme metabolizing P4 to T. Moreover, TBC in both studied concentrations increases P4 secretion in the culture medium. Finally, our studies have demonstrated an increase in the expression of Cyp19a1 mRNA, an enzyme metabolizing T to E2 , with a simultaneous increase in the amount of E2 in cells. Our data clearly show that TBC in an in vitro environment acts as EDCs, which may lead to serious consequences for the proper development and functioning of the brain.

Effect of the Use of Gnrh Analogs in Low-Grade Cerebral Glioma

Low-grade gliomas are the most common brain tumors in children. This tumor type presents a wide range of clinical, histological, and biological behaviors. In recent years, an association between estrogens and progesterone and the development of tumors has been suggested. A case of a 2-year-old girl is described with a low-grade brain tumor treated with chemotherapy and disease stabilization. The treatment with Decapeptyl® was initiated due to precocious puberty, and the tumor showed a decrease in its solid component-more than 50% of the initial size-three years after starting treatment. Several studies have described the influence of estrogen and progesterone on the development of gliomas, decreasing or increasing their expression in those tumors with greater aggressiveness, respectively. Despite the fact that the tumor-hormonal expression relationship in other tumor types has been evaluated, its role in the treatment of brain tumors remains unknown.

Identification of Gender- and Subtype-Specific Gene Expression Associated with Patient Survival in Low-Grade and Anaplastic Glioma in Connection with Steroid Signaling

Simple Summary

Gliomas are primary brain tumors that are initially slow growing but progress to be more aggressive and, ultimately, fatal within a few years. They are more common in men than in women, suggesting a protective role for female hormones. By analyzing patient data collected in the public TGCA-LGG database, we have demonstrated a link between the expression level of key steroid biosynthesis enzymes or hormone receptors with patient survival, in ways that are dependent on gender and molecular subtype. We also determined the genes which expression associated with these actors of steroid signaling and the functions they perform, to decipher the mechanisms underlying gender-dependent differences. Together, these results establish, for the first time, the involvement of hormones in low-grade and anaplastic gliomas and provide clues for refining their classification and, thus, facilitating more personalized management of patients.

Abstract

Low-grade gliomas are rare primary brain tumors, which fatally evolve to anaplastic gliomas. The current treatment combines surgery, chemotherapy, and radiotherapy. If gender differences in the natural history of the disease were widely described, their underlying mechanisms remain to be determined for the identification of reliable markers of disease progression. We mined the transcriptomic and clinical data from the TCGA-LGG and CGGA databases to identify male-over-female differentially expressed genes and selected those associated with patient survival using univariate analysis, depending on molecular characteristics (IDH wild-type/mutated; 1p/19q codeleted/not) and grade. Then, the link between the expression levels (low or high) of the steroid biosynthesis enzyme or receptors of interest and survival was studied using the log-rank test. Finally, a functional analysis of gender-specific correlated genes was performed. HOX-related genes appeared to be differentially expressed between males and females in both grades, suggesting that a glioma could originate in perturbation of developmental signals. Moreover, aromatase, androgen, and estrogen receptor expressions were associated with patient survival and were mainly related to angiogenesis or immune response. Therefore, consideration of the tight control of steroid hormone production and signaling seems crucial for the understanding of glioma pathogenesis and emergence of future targeted therapies.

Oral Contraceptive and Glioma Risk: A Prospective Cohort Study and Meta-Analysis

Background

Epidemiological evidence that glioma has a slight male predominance implies that factors associated with sex hormones may play a role in the development of glioma. The association between oral contraceptive (OC) use and glioma risk remains controversial.

Method

In the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial of 70,516 women in the USA, Cox proportional hazards regression analyses were adopted to calculate the crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Additionally, a meta-analysis combining the PLCO findings with those of other prospective cohorts was performed.

Results

During a mean follow-up of ~11.7 years, 110 of 70,516 women aged 50–78 years at baseline were diagnosed with glioma in PLCO studies. Compared with never users, an inverse association of borderline significance was found for OC users (HR 0.67, 95% CI 0.44–1.04, P = 0.074). Analyses assessing glioma risk according to the duration of OC use yielded no significant association. When PLCO was combined with four other prospective studies, there was an inverse association between OC use and glioma risk (HR 0.85, 95% CI 0.75–0.97, I² = 0.0%). Further dose-response analysis showed a nonlinear, inverse relationship between OC use and glioma risk (P < 0.001).

Conclusions

This study provided some evidence of a nonlinear, inverse association between OC use and glioma risk. Future larger studies are warranted to validate this finding.

Rapid Actions of the Nuclear Progesterone Receptor through cSrc in Cancer

The nuclear progesterone receptor (PR) is mainly known for its role as a ligand-regulated transcription factor. However, in the last ten years, this receptor’s extranuclear or rapid actions have gained importance in the context of physiological and pathophysiological conditions such as cancer. The PR’s polyproline (PXPP) motif allows protein–protein interaction through SH3 domains of several cytoplasmatic proteins, including the Src family kinases (SFKs). Among members of this family, cSrc is the most well-characterized protein in the scenario of rapid actions of the PR in cancer. Studies in breast cancer have provided the most detailed information on the signaling and effects triggered by the cSrc–PR interaction. Nevertheless, the study of this phenomenon and its consequences has been underestimated in other types of malignancies, especially those not associated with the reproductive system, such as glioblastomas (GBs). This review will provide a detailed analysis of the impact of the PR–cSrc interplay in the progression of some non-reproductive cancers, particularly, in GBs.

From GWAS to drug screening: repurposing antipsychotics for glioblastoma

BACKGROUND

Glioblastoma is currently an incurable cancer. Genome-wide association studies have demonstrated that 41 genetic variants are associated with glioblastoma and may provide an option for drug development.

METHODS

We investigated FDA-approved antipsychotics for their potential treatment of glioblastoma based on genome-wide association studies data using a 'pathway/gene-set analysis' approach.

RESULTS

The in-silico screening led to the discovery of 12 candidate drugs. DepMap portal revealed that 42 glioma cell lines show higher sensitivities to 12 candidate drugs than to Temozolomide, the current standard treatment for glioblastoma.

CONCLUSION

In particular, cell lines showed significantly higher sensitivities to Norcyclobenzaprine and Protriptyline which were predicted to bind targets to disrupt a certain molecular function such as DNA repair, response to hormones, or DNA-templated transcription, and may lead to an effect on survival-related pathways including cell cycle arrest, response to ER stress, glucose transport, and regulation of autophagy. However, it is recommended that their mechanism of action and efficacy are further determined.

Body mass index and glioma risk: A prospective multicenter study

BACKGROUND

The association between glioma risk and body mass index (BMI) remains obscure.

METHODS

This study aimed to assess the association between glioma risk and BMI in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Cox proportional hazards regression was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

The onset of a total of 269 gliomas was observed during a median follow-up period of 12.04 years. Compared with the normal weight, overweight (HR: 1.05; 95% CI: 0.80, 1.39) and obesity (HR: 0.91; 95% CI: 0.56, 1.39) were not significantly associated with glioma risk. Further analysis showed a nonlinear relationship between glioma risk and BMI in men but not women. The multivariable-adjusted HRs per unit increase in BMI were 0.94 (95% CI: 0.89, 1.00; P = 0.037) in men with BMI >25 kg/m² and 1.16 (95% CI: 0.98, 1.38; P = 0.075) in men with BMI <25 kg/m².

CONCLUSION

The present data provide evidence that there may be a nonlinear association between BMI and glioma risk in men. The risk of glioma decreased with increasing BMI among men with BMI >25 kg/m². Future studies are needed to validate our observation.

Progesterone suppresses the progression of colonic carcinoma by increasing the activity of the GADD45α/JNK/c‑Jun signalling pathway

Colorectal cancer (CRC) is the third most diagnosed cancer worldwide. Progesterone is associated with a decreased risk of CRC and leads to a favourable prognosis. However, the specific mechanism by which progesterone suppresses malignant progression remains to be elucidated. In the present study, the level of progesterone was first analysed in 77 patients with CRC, and immunohistochemistry was performed to detect the expression of progesterone receptor (PGR) in the paired specimens. The correlations between progesterone, PGR and CRC prognosis were assessed. A Cell Counting Kit-8 assay was then used to detect proliferation of the CRC cells. Flow cytometry was performed to estimate apoptosis and to evaluate the cycle of the CRC cells. A xenograft tumour model was established in nude mice to assess the role of progesterone in tumour growth. Finally, a PCR microarray was used to screen differentially expressed genes to further interpret the mechanism by which progesterone inhibits the malignant progression of CRC. It was found that low expression of progesterone and PGR were significantly associated with poor prognosis of CRC. In addition, progesterone suppressed CRC cell proliferation by arresting the cell cycle and inducing apoptosis in vitro. Moreover, the inhibitory role of progesterone in tumour growth was verified in vivo. Further investigation showed that the level of growth arrest and DNA damage-inducible protein α (GADD45α) was up-regulated by progesterone, and this was followed by the activation of the JNK pathway. Progesterone increased the activity of the JNK pathway via GADD45α to inhibit proliferation by arresting the cell cycle and inducing apoptosis, thereby suppressing the malignant progression of CRC. Therefore, it can be concluded that progesterone and PGR might act as inhibiting factors for poor prognosis of CRC.

Patterns of Interaction Between Diffuse Low-Grade Glioma and Pregnancy: An Institutional Case Series

BACKGROUND

The occurrence of pregnancy in patients with low-grade glioma (LGG) constitutes a unique therapeutic challenge. Owing to the rarity of cases, there is a dearth of information in existing literature.

METHODS

We retrospectively identified all patients with a diagnosis of LGG and pregnancy at some point during their illness. Clinical course and obstetrical outcomes were reviewed. A volumetric analysis of tumor growth rate in association with pregnancy was performed.

RESULTS

Of 15 women identified, 13 (86.7%) had a prepregnancy LGG diagnosis. Of the 2 patients in whom LGG was diagnosed during pregnancy, one underwent upfront surgery, and the other had watchful waiting with resection after 60 weeks. Nine patients (60.0%) remained asymptomatic during pregnancy, while 5 (33.3%) experienced recurrence of seizures. There was one case of transformation of an astrocytoma to glioblastoma during the third trimester, which was resected emergently. In 10 cases, progression occurred after pregnancy at a median interval of 24.2 months (interquartile range 6.6-37.5 months), with progression within 6 months of delivery in 2 cases. Mean (SD) growth rate during pregnancy was 7.8 (22.2) mm/year compared with 0.62 (1.12) mm/year before pregnancy and 0.29 (1.18) mm/year after pregnancy; the difference did not reach statistical significance (P = 0.306).

CONCLUSIONS

Pregnancy was associated with clinical deterioration in one third of patients. No significant change in growth rate was identified. Time to progression and malignant dedifferentiation were unaffected. Patients with LGG wishing to pursue pregnancy should be counseled regarding the risk of complications, and if pregnancy is pursued, close neurological and obstetrical follow-up is recommended.

The Complex Interplay between Endocannabinoid System and the Estrogen System in Central Nervous System and Periphery

The endocannabinoid system (ECS) is a lipid cell signaling system involved in the physiology and homeostasis of the brain and peripheral tissues. Synaptic plasticity, neuroendocrine functions, reproduction, and immune response among others all require the activity of functional ECS, with the onset of disease in case of ECS impairment. Estrogens, classically considered as female steroid hormones, regulate growth, differentiation, and many other functions in a broad range of target tissues and both sexes through the activation of nuclear and membrane estrogen receptors (ERs), which leads to genomic and non-genomic cell responses. Since ECS function overlaps or integrates with many other cell signaling systems, this review aims at updating the knowledge about the possible crosstalk between ECS and estrogen system (ES) at both central and peripheral level, with focuses on the central nervous system, reproduction, and cancer.

The Sex Bias of Cancer

In hormone-dependent organs, sex hormones and dysregulated hormone signaling have well-documented roles in cancers of the breast and female reproductive organs including endometrium and ovary, as well as in prostate and testicular cancers in males. Strikingly, epidemiological data highlight significant differences between the sexes in the incidence of various cancers in nonreproductive organs, where the role of sex hormones has been less well studied. In an era when personalized medicine is gaining recognition, understanding the molecular, cellular, and biological differences between men and women is timely for developing more appropriate therapeutic interventions according to gender. We review evidence that sex hormones also shape many of the dysregulated cellular and molecular pathways that lead to cell proliferation and cancer in nonreproductive organs.

The Role of mPRδ and mPRε in Human Glioblastoma Cells: Expression, Hormonal Regulation, and Possible Clinical Outcome

Glioblastomas (GBM) are the most frequent and aggressive primary tumor of the central nervous system. In recent years, it has been proposed that sex hormones such as progesterone play an essential role in GBM biology. Membrane progesterone receptors (mPRs) are a group of G protein-coupled receptors with a wide distribution and multiple functions in the organism. There are five mPRs subtypes described in humans: mPRα, mPRβ, mPRγ, mPRδ, and mPRε. It has been reported that human-derived GBM cells express the mPRα, mPRβ, and mPRγ subtypes, and that progesterone promotes GBM progression in part by mPRα specific activation; however, it is still unknown if mPRδ and mPRε are also expressed in this type of tumor cells. In this study, we characterized the expression and hormonal regulation of mPRδ and mPRε in human GBM cells. We also analyzed a set of biopsies from TCGA. We found that the expression of these receptors is dependent on the tumor's grade and that mPRδ expression is directly correlated to patients' survival while the opposite is observed for mPRε. By RT-qPCR, Western blot, and immunofluorescence, the expression of mPRδ and mPRε was detected for the first time in human GBM cells. An in silico analysis showed possible progesterone response elements in the promoter regions of mPRδ and mPRε, and progesterone treatments downregulated the expression of these receptors. Our results suggest that mPRδ and mPRε are expressed in human GBM cells and that they are relevant to GBM biology.

The role of the prolactin receptor pathway in the pathogenesis of glioblastoma: what do we know so far?

Introduction: Prolactin (PRL) and its receptor (PRLR) have been associated with the development of hormone-dependent tumors and have been detected in glioblastoma (GBM) biopsies. GBM is the most common and aggressive primary brain tumor in adults and the prognosis for patients is dismal; hence researchers are exploring the PRLR pathway as a therapeutic target in this disease. Areas covered: This paper explores the effects of PRLR activation on the biology of GBM, the correlation between PRL and PRLR expression and GBM progression and survival in male and female patients. Finally, we discuss how a better understanding of the PRLR pathway may allow the development of novel treatments for GBM. Expert opinion: We propose PRL and PRLR as potential prognosis biomarkers and therapeutic targets in GBM. Local administration of PRLR inhibitors using gene therapy may offer a beneficial strategy for targeting GBM cells disseminated in the non-neoplastic brain; however, efficacy and safety require careful and extensive evaluation. The data depicted herein underline the need to (i) improve our understanding of sexual dimorphism in GBM, and (ii) develop accurate preclinical models that take into consideration different hormonal contexts, specific genetic alterations, and tumor grades.

Acute post-partum vision loss due to pilocytic astrocytoma

Purpose

We report an unusual case of a thirty-three-year-old woman who presented with acute unilateral vision loss following pregnancy and was ultimately discovered to have a pilocytic astrocytoma of the optic nerve.

Observations

A thirty-three-year-old previously healthy female presented one month following Caesarean section with unilateral vision loss. She was found to have significantly decreased visual acuity, an afferent pupil deficit, proptosis, optic nerve edema and choroidal folds. Imaging revealed a large lesion of the optic nerve. Biopsy was performed and pathologic analysis revealed a pilocytic astrocytoma, WHO grade 1. The patient opted for close observation without further management and demonstrated mild improvement in visual function.

Conclusions/Importance

Optic pathway gliomas (OPG) most commonly present in the pediatric patient population with painless proptosis, slowly progressive vision loss, and clinical findings of chronic optic neuropathy.( Farazdaghi et al., 2019 Sep) 1 Acute presentations of this disease in adulthood are rare. This case demonstrates a rare case of acute optic nerve glioma presentation during the post-partum period.

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.

A Coexisting Pilocytic Astrocytoma and a Prolactinoma: A Case Report of Collision Tumors and Literature Review

Pituitary adenomas and gliomas constitute two of the most common primary intracranial tumors. However, their coexistence as collision tumors is relatively rare and few similar reports could be identified in the literature. In this study, we report a case of a 64-year-old male patient with a prolactinoma and a pilocytic astrocytoma in collision. The patient underwent both an endoscopic transsphenoidal approach and a subfrontal craniotomy, achieving a gross total resection of the concomitant lesions in the sellar and suprasellar regions. Postoperatively, the patient's preoperative bitemporal hemianopsia resolved and no new deficits occurred. At his six-month follow-up, he remained free of neurologic deficits. Although causative factors are yet to be determined for these tumors in collision, their nonsyndromic coexistence could point to a common genetic linkage which will help to shed light on their natural history of occurrence.

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.

Testosterone Promotes Glioblastoma Cell Proliferation, Migration, and Invasion Through Androgen Receptor Activation

Glioblastomas (GBM) are the most frequent and aggressive human brain tumors due to their high capacity to migrate and invade normal brain tissue. Epidemiological data report that GBM occur in a greater proportion in men than in women (3:2), suggesting the participation of sex hormones in the development of these tumors. It has been reported an increase in testosterone (T) levels in patients with GBM. In addition, androgen receptor (AR) is overexpressed in human GBM, and genetic silencing of AR, and its pharmacological inhibition, induce GBM cell death in vivo and in vitro. However, the role of T in proliferation, migration and invasion in human GBM cell lines has not been evaluated. We observed that T increased the number of U87, U251, and D54 cells derived from human GBM due to an increase in cell proliferation. This induction was blocked with flutamide, an antagonist of AR. T also induced migration and invasion of GBM cells that flutamide partially blocked. These data suggest that T through AR contributes to the progression of GBM by promoting proliferation, migration, and invasion.

Mifepristone Overcomes Tumor Resistance to Temozolomide Associated with DNA Damage Repair and Apoptosis in an Orthotopic Model of Glioblastoma

The standard treatment for glioblastoma multiforme (GBM) is surgery followed by chemo/radiotherapy. A major limitation on patient improvement is the high resistance of tumors to drug treatment, likely responsible for their subsequent recurrence and rapid progression. Therefore, alternatives to the standard therapy are necessary. The aim of the present study was to evaluate whether mifepristone, an antihormonal agent, has a synergistic effect with temozolomide (used in standard therapy for gliomas). Whereas the mechanism of temozolomide involves damage to tumor DNA leading to apoptosis, tumor resistance is associated with DNA damage repair through the O⁶-methylguanine-DNA-methyltransferase (MGMT) enzyme. Temozolomide/mifepristone treatment, herein examined in Wistar rats after orthotopically implanting C6 glioma cells, markedly reduced proliferation. This was evidenced by a decreased level of the following parameters: a proliferation marker (Ki-67), a tumor growth marker (¹⁸F-fluorothymidine uptake, determined by PET/CT images), and the MGMT enzyme. Increased apoptosis was detected by the relative expression of related proteins, (e.g. Bcl-2 (B-cell lymphoma 2), Bax (bcl-2-like protein 4) and caspase-3). Thus, greater apoptosis of tumor cells caused by their diminished capacity to repair DNA probably contributed significantly to the enhanced activity of temozolomide. The results suggest that mifepristone could possibly act as a chemo-sensitizing agent for temozolomide during chemotherapy for GBM.

Author Correction: Genetically engineered cerebral organoids model brain tumor formation

In the originally published paper, the "before" image for the afatinib condition in Fig. 6c was incorrect. Instead of an image displaying a GBM-3 neoplastic organoid before afatinib treatment, this panel showed an image from the GBM-2 control (DMSO) group before treatment. This error has now been corrected in the HTML and PDF versions of the article; the "before, afatinib" panel in Fig. 6c now shows a representative image from the indicated experiment. The color of all error bars in Fig. 6 has also been changed to black, for consistency. All statistical analysis and all conclusions presented in the article are unaffected by this error. Nevertheless, we apologize for the mistake.

Genetically engineered cerebral organoids model brain tumor formation

Brain tumours are among the most lethal and devastating cancers. Their study is limited by genetic heterogeneity and the incompleteness of available laboratory models. Three-dimensional organoid culture models offer innovative possibilities for modelling human disease. Here, we establish a 3D in vitro model, named neoplastic cerebral organoid (neoCOR), in which we recapitulate brain tumorigenesis by introducing oncogenic mutations in cerebral organoids via transposon- and CRISPR/Cas9-mediated mutagenesis. By screening clinically-relevant mutations identified in cancer genome projects, we define mutation combinations that result in glioblastoma-like and central nervous system primitive neuroectodermal tumour (CNS-PNET)-like neoplasms. We demonstrate that neoCORs are suitable to study aspects of tumour biology such as invasiveness, and to evaluate the effect of drugs in the context of specific DNA aberrations. neoCORs will provide a valuable complement to current basic and preclinical models for studying brain tumour biology.

Hypoxic regulation of the expression of genes encoded estrogen related proteins in U87 glioma cells: eff ect of IRE1 inhibition

OBJECTIVE

The aim of the present study was to examine the effect of inhibition of endoplasmic reticulum stress signaling, mediated by IRE1 (inositol requiring enzyme 1), which is a central mediator of the unfolded protein response on the expression of genes encoded estrogen related proteins (NRIP1/RIP140, TRIM16/EBBP, ESRRA/NR3B1, FAM162A/E2IG5, PGRMC2/PMBP, and SLC39A6/LIV-1) and their hypoxic regulation in U87 glioma cells for evaluation of their possible significance in the control of glioma cells proliferation.

METHODS

The expression of NRIP1, EBBP, ESRRA, E2IG5, PGRMC2, and SLC39A6 genes in U87 glioma cells, transfected by empty vector pcDNA3.1 (control) and cells without IRE1 signaling enzyme function (transfected by dnIRE1) upon hypoxia, was studied by a quantitative polymerase chain reaction.

RESULTS

Inhibition of both enzymatic activities (kinase and endoribonuclease) of IRE1 signaling enzyme function up-regulates the expression of EBBP, E2IG5, PGRMC2, and SLC39A6 genes is in U87 glioma cells in comparison with the control glioma cells, with more significant changes for E2IG5 and PGRMC2 genes. At the same time, the expression of NRIP1 and ESRRA genes is strongly down-regulated in glioma cells upon inhibition of IRE1. We also showed that hypoxia increases the expression of E2IG5, PGRMC2, and EBBP genes and decreases NRIP1 and ESRRA genes expression in control glioma cells. Furthermore, the inhibition of IRE1 in U87 glioma cells decreases the eff ect of hypoxia on the expression of E2IG5 and PGRMC2 genes, eliminates hypoxic regulation of NRIP1 gene, and enhances the sensitivity of ESRRA gene to hypoxic condition. Furthermore, the expression of SLC39A6 gene is resistant to hypoxia in both the glioma cells with and without IRE1 signaling enzyme function.

CONCLUSIONS

Results of this investigation demonstrate that inhibition of IRE1 signaling enzyme function affects the expression of NRIP1, EBBP, ESRRA, E2IG5, PGRMC2, and SLC39A6 genes in U87 glioma cells in gene specific manner and these changes possibly contribute to the suppression of the cell proliferation. Most of these genes are regulated by hypoxia and preferentially through IRE1 signaling pathway of endoplasmic reticulum stress.