RAS Promotes Proliferation and Resistances to Apoptosis in Meningioma

The FGF6 amplification mutation plays an important role in the progression and treatment of malignant meningioma

Meningioma is a benign tumor with slow growth and long course. However, patients with recurrent malignant meningioma still face a lack of effective treatment. Here, we report a rare case of primary mediastinal malignant meningioma with lung and bone metastases, who benefited from the treatment of apatinib (≥33 months) and anlotinib (until the publication date). Retrospective molecular analysis revealed the frequent amplification of FGF6 in primary and metastatic lesions. Then we constructed the FGF6 over-expressed IOMM-LEE and CH157MN malignant meningioma cell lines, and in vitro and vivo experiments showed that overexpression of FGF6 can promote the proliferation, migration and invasion of malignant meningioma cells. Based on the Western analysis, we revealed that FGF6 can promote the phosphorylation of FGFR, AKT, and ERK1/2, which can be inhibited by anlotinib. Together, we were the first to verify that overexpression of FGF6 promotes the progression of malignant meningiomas by activating FGFR/AKT/ERK1/2 pathway and pointed out that anlotinib may effectively inhibit the disease progression of patients with FGF6 amplification.

Unveiling a Biomarker Signature of Meningioma: The Need for a Panel of Genomic, Epigenetic, Proteomic, and RNA Biomarkers to Advance Diagnosis and Prognosis

Meningiomas are the most prevalent primary intracranial tumors. The majority are benign but can undergo dedifferentiation into advanced grades classified by World Health Organization (WHO) into Grades 1 to 3. Meningiomas' tremendous variability in tumor behavior and slow growth rates complicate their diagnosis and treatment. A deeper comprehension of the molecular pathways and cellular microenvironment factors implicated in meningioma survival and pathology is needed. This review summarizes the known genetic and epigenetic aberrations involved in meningiomas, with a focus on neurofibromatosis type 2 (NF2) and non-NF2 mutations. Novel potential biomarkers for meningioma diagnosis and prognosis are also discussed, including epigenetic-, RNA-, metabolomics-, and protein-based markers. Finally, the landscape of available meningioma-specific animal models is overviewed. Use of these animal models can enable planning of adjuvant treatment, potentially assisting in pre-operative and post-operative decision making. Discovery of novel biomarkers will allow, in combination with WHO grading, more precise meningioma grading, including meningioma identification, subtype determination, and prediction of metastasis, recurrence, and response to therapy. Moreover, these biomarkers may be exploited in the development of personalized targeted therapies that can distinguish between the 15 diverse meningioma subtypes.

Meningioma animal models: a systematic review and meta-analysis

BACKGROUND

Animal models are widely used to study pathological processes and drug (side) effects in a controlled environment. There is a wide variety of methods available for establishing animal models depending on the research question. Commonly used methods in tumor research include xenografting cells (established/commercially available or primary patient-derived) or whole tumor pieces either orthotopically or heterotopically and the more recent genetically engineered models-each type with their own advantages and disadvantages. The current systematic review aimed to investigate the meningioma model types used, perform a meta-analysis on tumor take rate (TTR), and perform critical appraisal of the included studies. The study also aimed to assess reproducibility, reliability, means of validation and verification of models, alongside pros and cons and uses of the model types.

METHODS

We searched Medline, Embase, and Web of Science for all in vivo meningioma models. The primary outcome was tumor take rate. Meta-analysis was performed on tumor take rate followed by subgroup analyses on the number of cells and duration of incubation. The validity of the tumor models was assessed qualitatively. We performed critical appraisal of the methodological quality and quality of reporting for all included studies.

RESULTS

We included 114 unique records (78 using established cell line models (ECLM), 21 using primary patient-derived tumor models (PTM), 10 using genetically engineered models (GEM), and 11 using uncategorized models). TTRs for ECLM were 94% (95% CI 92-96) for orthotopic and 95% (93-96) for heterotopic. PTM showed lower TTRs [orthotopic 53% (33-72) and heterotopic 82% (73-89)] and finally GEM revealed a TTR of 34% (26-43).

CONCLUSION

This systematic review shows high consistent TTRs in established cell line models and varying TTRs in primary patient-derived models and genetically engineered models. However, we identified several issues regarding the quality of reporting and the methodological approach that reduce the validity, transparency, and reproducibility of studies and suggest a high risk of publication bias. Finally, each tumor model type has specific roles in research based on their advantages (and disadvantages).

SYSTEMATIC REVIEW REGISTRATION

PROSPERO-ID CRD42022308833.

Modeling Meningiomas: Optimizing Treatment Approach

Preclinical meningioma models offer a setting to test molecular mechanisms of tumor development and targeted treatment options but historically have been challenging to generate. Few spontaneous tumor models in rodents have been established, but cell culture and in vivo rodent models have emerged along with artificial intelligence, radiomics, and neural networks to differentiate the clinical heterogeneity of meningiomas. We reviewed 127 studies using PRISMA guideline methodology, including laboratory and animal studies, that addressed preclinical modeling. Our evaluation identified that meningioma preclinical models provide valuable molecular insight into disease progression and effective chemotherapeutic and radiation approaches for specific tumor types.

Preclinical Models of Meningioma

The management of clinically aggressive meningiomas remains challenging due to limited treatment options aside from surgical removal and radiotherapy. High recurrence rates and lack of effective systemic therapies contribute to the unfavorable prognosis of these patients. Accurate in vitro and in vivo models are critical for understanding meningioma pathogenesis and to identify and test novel therapeutics. In this chapter, we review cell models, genetically engineered mouse models, and xenograft mouse models, with special emphasis on the field of application. Finally, promising preclinical 3D models such as organotypic tumor slices and patient-derived tumor organoids are discussed.

PROPHYLACTIC EFFECT OF NITRIC OXIDE DONORS ON RAT MODELS OF EGFR INHIBITORS-INDUCED CUTANEOUS TOXICITIES

Epidermal growth factor receptor inhibitors (EGFRIs) have been established as first-line standard-of-care therapies for non-small cell lung cancer (NSCLC) but are frequently accompanied by adverse dermatological effects, in particular, acneiform rash. There is no effective clinical intervention, partially because of its poorly understood etiology. Here, we show that inhibition of EGFR initiated keratinocyte HaCaT cell cycle arrest and apoptosis, which fueled a robust secondary inflammatory response. Rats gavaged with EGFRI showed a phenotype similar to that of clinical patients, which was in line with the interrupted functions observed in HaCaT keratinocytes. We found that a nitric oxide (NO) donor, nitroglycerin (GTN), was a feasible treatment alternative for EGFRI-induced rash. Restoration of epidermal extracellular signal-regulated kinase (ERK) and a reduction in STAT3 signaling via GTN treatment rescued the cellular functions that had been damaged in vitro and further ameliorated the rash in rat models. In addition, the efficacy of GTN was superior to that of existing clinical interventions. These data highlighted the importance of epidermal EGFR signaling and led to the identification of a small-molecule NO donor as a mediator that can maintain EGFR pathway functions during anti-EGFR therapies, providing a therapeutic anchor point for adverse EGFRI-induced skin effects.

Mouse Models in Meningioma Research: A Systematic Review

Meningiomas are the most frequent primitive central nervous system tumors found in adults. Mouse models of cancer have been instrumental in understanding disease mechanisms and establishing preclinical drug testing. Various mouse models of meningioma have been developed over time, evolving in light of new discoveries in our comprehension of meningioma biology and with improvements in genetic engineering techniques. We reviewed all mouse models of meningioma described in the literature, including xenograft models (orthotopic or heterotopic) with human cell lines or patient derived tumors, and genetically engineered mouse models (GEMMs). Xenograft models provided useful tools for preclinical testing of a huge range of innovative drugs and therapeutic options, which are summarized in this review. GEMMs offer the possibility of mimicking human meningiomas at the histological, anatomical, and genetic level and have been invaluable in enabling tumorigenesis mechanisms, including initiation and progression, to be dissected. Currently, researchers have a range of different mouse models that can be used depending on the scientific question to be answered.

YAP1-FAM118B Fusion Defines a Rare Subset of Childhood and Young Adulthood Meningiomas

Meningiomas are a central nervous system tumor primarily afflicting adults, with <1% of cases diagnosed during childhood or adolescence. Somatic variation in NF2 may be found in ∼50% of meningiomas, with other genetic drivers (eg, SMO, AKT1, TRAF7) contributing to NF2 wild-type tumors. NF2 is an upstream negative regulator of YAP signaling and loss of the NF2 protein product, Merlin, results in YAP overexpression and target gene transcription. This mechanism of dysregulation is described in NF2-driven meningiomas, but further work is necessary to understand the NF2-independent mechanism of tumorigenesis. Amid our institutional patient-centric comprehensive molecular profiling study, we identified an individual with meningioma harboring a YAP1-FAM118B fusion, previously reported only in supratentorial ependymoma. The tumor histopathology was remarkable, characterized by prominent islands of calcifying fibrous nodules within an overall collagen-rich matrix. To gain insight into this finding, we subsequently evaluated the genetic landscape of 11 additional pediatric and adolescent/young adulthood meningioma patients within the Children's Brain Tumor Tissue Consortium. A second individual harboring a YAP1-FAM118B gene fusion was identified within this database. Transcriptomic profiling suggested that YAP1-fusion meningiomas are biologically distinct from NF2-driven meningiomas. Similar to other meningiomas, however, YAP1-fusion meningiomas demonstrated overexpression of EGFR and MET. DNA methylation profiling further distinguished YAP1-fusion meningiomas from those observed in ependymomas. In summary, we expand the genetic spectrum of somatic alteration associated with NF2 wild-type meningioma to include the YAP1-FAM118B fusion and provide support for aberrant signaling pathways potentially targetable by therapeutic intervention.

Twist1 sustains the apoptosis resistance in eosinophils in nasal mucosa of allergic rhinitis

Eosinophils (Eos) are the canonical effector cells in allergic rhinitis (AR) and many inflammatory diseases. The mechanism of eosinophilia occurring in the lesion sites is not fully understood yet. Twist1 protein (Twist, in short) is an apoptosis inhibitor that also has immune regulatory functions. This study aims to investigate the role of Twist in the pathogenesis of eosinophilia in AR. In this study, surgically removed human nasal mucosal samples were obtained from patients with chronic sinusitis and nasal polyps with AR (the AR group) or without AR (the nAR group). Eos were isolated from the samples by flow cytometry. We found that abundant Eos were obtained from the surgically removed nasal mucosa tissues of both nAR and AR groups. Significantly higher Ras activation was detected in AR Eos than that in nAR Eos. Ras activation was associated with the apoptosis resistance in AR Eos. The Twist (an apoptosis inhibitor) expression was higher in AR Eos, which was positively correlated with the Ras activation status. The sensitization to IgG induced Twist expression in Eos, in which Ras activated the MAPK-HIF-1α pathway, the latter promoted the Twist gene transcription. Twist bound Rac GTPase activating protein-1 to sustain the Ras activation in Eos. Ras activation sustained the apoptosis resistance in Eos. In conclusion, high Ras activation was detected in the AR nasal mucosal tissue-isolated Eos. IgG-sensitization induced Ras activation and Twist expression in Eos, that conferred Eos the apoptosis resistance.

Quercetin induces apoptosis in meningioma cells through the miR-197/IGFBP5 cascade

To investigate the effects of quercetin on cell viability and apoptosis in meningioma cells and to determine the underlying molecular mechanism. HBL-52 meningioma cells were treated with quercetin at doses of 1, 5, 10, 20, and 40 ng/mL for 24, 36 and 48 h, and cell viability was assessed using the Cell Counting kit-8 (CCK-8) test. Apoptosis was determined by flow cytometry. Bax, Bcl-2, and IGFBP5 protein expression was assessed by western blot, and IGFBP5 and miR-197 mRNA levels were measured using quantitative reverse transcription PCR (qRT-PCR). The interaction between miR-197 and IGFBP5 was verified by dual luciferase assay. Quercetin reduces viability and proliferation and increases apoptosis in HBL-52 cells in a dose- and time-dependent manner. Quercetin treatment also decreases Bcl-2 and increases Bax protein expression, and increases miR-197 mRNA while reducing IGFBP5 mRNA expression. A dual luciferase assay showed that miR-197 interacts directly with binding sites in the 3'untranslated region of IGFBP5, and that miR-197 overexpression reduced IGFBP5 expression. Quercetin may reduce meningioma cell proliferation and increase apoptosis by activating the miR-197/IGFBP5 cascade and regulating Bcl-2/Bax.

Molecular Mechanism and Approach in Progression of Meningioma

Meningioma is the most common tumor of the central nervous system, most of which is benign. Even after complete resection, a high rate of recurrence of meningioma is observed. From in-depth study of its pathogenesis, it has been found that a number of chromosomal variations and abnormal molecular signals are closely related to the occurrence and development of malignancy in meningioma, which may provide the theoretical basis and potential direction for accurate and targeted treatment. We have reviewed advances in chromosomal variations and molecular mechanisms involved in the progression of meningioma, and have highlighted the association with malignant biological behavior including cell proliferation, angiogenesis, increased invasiveness, and inhibition of apoptosis. In addition, the chemotherapy of meningioma is summarized and discussed.

Resveratrol Inhibits Proliferation in HBL-52 Meningioma Cells

Objective

To investigate the effects of resveratrol on apoptosis and proliferation in meningioma cells and characterize the underlying molecular mechanism.

Methods

HBL-52 meningioma cells were treated with resveratrol at doses of 10, 50, 100, 200, and 400 μM for 24, 36, and 48 hrs. Inhibition of proliferation was measured by CCK8 assay, and apoptosis was determined by annexin V staining and flow cytometry. Expression of apoptosis-associated proteins (cleaved-caspase-3, pro-caspase-3) and Bcl-2 were measured by Western blot. Levels of miR-34a-3p and Bcl-2 mRNA were analyzed by reverse transcriptase PCR. A dual luciferase assay was used to determine whether miR-34a-3p binds to the 3ʹUTR of Bcl-2.

Results

Resveratrol reduces proliferation and increases apoptosis in HBL-52 cells. These effects increase with increasing resveratrol concentration and exposure time. Resveratrol increases levels of cleaved-caspase 3 protein as well as decreases levels of pro-caspase 3 protein and Bcl-2 mRNA. The 3ʹUTR of Bcl-2 contains putative binding sites for miR-34a-3p, and these binding sites can regulate the expression of a luciferase reporter. Overexpression of miR-34a-3p reduces Bcl-2 protein levels in HBL-52 cells.

Conclusion

Resveratrol suppresses proliferation and induces apoptosis in meningioma cells by upregulating miR-34a-3p, which in turn downregulates Bcl-2. Resveratrol may be a useful drug for treating meningiomas.

Meningioma: Signaling pathways and tumor growth

Meningiomas are the most common primary intracranial brain tumor in adult humans; however, our understanding of meningioma tumorigenesis is relatively limited in comparison with the body of research available for other intracranial tumors such as gliomas. Here we briefly describe the current understanding of aberrant signaling pathways and tumor growth mechanisms responsible for meningioma differentiation, cellular growth, development, inhibition, and death. Numerous cellular functions impacted by these signaling pathways are critical for angiogenesis, proliferation, and apoptosis. Ultimately, a further understanding of the signaling pathways involved in meningioma tumorigenesis will lead to better treatment modalities in the future.

Next generation sequencing identifies novel potential actionable mutations for grade I meningioma treatment

Meningiomas are common brain tumors that arise from the meningeal membranes that envelope the brain and spinal cord. The World Health Organization classifies these tumors into three histopathological grades. Because of tumor recurrence, treating meningiomas may be challenging even in well-differentiated grade I (GI) neoplasms. Indeed, around 5% of completely resected GI meningiomas relapse within 5 years. Therefore, identifying driver mutations in GI meningiomas through next generation sequencing (NGS) assays is paramount. The aim of this study was to validate the use of the 50-gene AmpliSeq Hotspot Cancer Panel v2 to identify the mutational status of 23 GI meningioma, namely, 12 non recurrent and 11 recurrent. In 18 out of the 23 GI meningiomas analyzed, we identified at least one gene mutation (78.2%). The most frequently mutated genes were c-kit (39.1%), ATM (26.1%), TP53 (26.1%), EGFR (26.1%), STK11 (21.7%), NRAS (17.4%), SMAD4 (13%), FGFR3 (13%), and PTPN11 (13%); less frequent mutations were SMARCB1 (8.7%), FLT3 (8.7%), KRAS (8.7%), FBWX7 (8.7%), ABL1 (8.7%), ERBB2 (8.7%), IDH1 (8.7%), BRAF (8.7%), MET (8.7%), HRAS (4.3%), RB1 (4.3%), CTNNB1 (4.3%), PIK3CA (4.3%), VHL (4.3%), KDR (4.3%), APC (4.3%), NOTCH1 (4.3%), JAK3 (4.3%), and SRC (4.3%). To our knowledge, mutations in all of these genes, except for TP53, STK11, SMARCB1, PIK3CA, VHL, and BRAF, have never been described before in meningiomas. Hence, these findings demonstrate the viability of NGS to detect new genetic alterations in GI meningiomas. Equally important, this technology enabled us to detect possible novel actionable mutations not previously associated with GI and for which selective inhibitors already exist.

High expression of PIWIL2 promotes tumor cell proliferation, migration and predicts a poor prognosis in glioma

Piwi-like RNA-mediated gene silencing 2 (PIWIL2), has been reported as an oncogene tightly associated with the genesis and progression of various malignancies. Nevertheless, the function of the PIWIL2 protein in human gliomas has not yet been clarified. In this study, we sought to investigate the clinical significance of PIWIL2 expression and reveal its function in the pathological process of gliomas. Through western blot and immunohistochemical analyses we found that PIWIL2 was overexpressed in glioma tissues. Moreover, the expression level of PIWIL2 was also significantly correlated with the WHO grades of human gliomas and Ki-67 expression. Kaplan‑Meier curves indicated that PIWIL2 was a prognostic factor for the survival of glioma patients and a high expression of PIWIL2 was correlated with a poor prognosis. In vitro, knockdown of PIWIL2 in glioma cells was shown to induce cell cycle arrest and increase apoptosis. Furthermore, silencing of PIWIL2 expression also obviously suppressed the migration of glioma cells. All the results demonstrated that PIWIL2 plays a significant role in the pathogenesis of human gliomas and may be used as a potential diagnostic marker and a therapeutic target of glioma in the future.

Di2-ethylhexyl phthalate disrupts thyroid hormone homeostasis through activating the Ras/Akt/TRHr pathway and inducing hepatic enzymes

Di(2-ethylhexyl) phthalate (DEHP), as a widespread environmental pollutant and an endocrine disruptor, can disturb the homeostasis of thyroid hormones (THs). In order to elucidate roles of the MAPK and PI3K/Akt pathways and hepatic enzymes in thyroid-disrupting effects of DEHP, Sprague-Dawley rats were dosed with DEHP by gavage for 30 consecutive days; Nthy-ori 3-1 cells were treated with DEHP with NAC, k-Ras siRNA or inhibitors (U0126 and wortmannin). Results showed that DEHP led to histopathologic changes in rat thyroid and liver, such as the decrease in thyroid follicular cavity diameter, hepatocyte edema. Triiodothyronine (T3), thyroxine (T4) and thyrotropin releasing hormone (TRH) were reduced. DEHP caused ROS production, oxidative stress and k-Ras upregulation, thereby activating the ERK and Akt pathways in vivo and in vitro. Moreover, TRH receptor (TRHr) level was elevated after the activation of the Akt pathway and was downregulated after the inhibition of the Akt pathway. However, TRHr was not modulated by the ERK pathway. Additionally, hepatic enzymes, including Ugt1a1, CYP2b1, Sult1e1, and Sult2b1, were significantly induced after DEHP exposure. Taken together, DEHP can perturb TH homeostasis and reduce TH levels. The activated Ras/Akt/TRHr pathway and induced hepatic enzymes play vital roles in thyroid-disrupting effects of DEHP.