Frequent AKT1E17K mutations in skull base meningiomas are associated with mTOR and ERK1/2 activation and reduced time to tumor recurrence

Histomolecular characterization of intracranial meningiomas developed in patients exposed to high-dose cyproterone acetate: an antiandrogen treatment

Background

Meningiomas are the most common primary intracranial tumors in adults. The relationship between meningiomas and exogenous sex hormones such as cyproterone acetate (CPA) is well documented, yet the underlying mechanisms remain unknown. Defining the histomolecular status of meningiomas developed on CPA would help us to better understand the oncogenesis of these tumors.

Methods

We identified 30 patients operated for a meningioma after long-term high-dose CPA therapy and with a history of CPA discontinuation before establishing the indication for surgical intervention. We used array-comparative genomic hybridization (to characterize copy number changes in those 30 meningiomas and subsequently performed next-generation sequencing with the National Institute of Cancer (INCa) solid tumor panel, which is a targeted panel of clinically actionable genes. We also examined grade, type, and clinical features.

Results

We identified AKT1 mutations or PIK3CA mutations in 33.3% of CPA meningiomas. AKT1 and PIK3CA mutations were mutually exclusive. Enrichment in oncogenic PIK3CA mutations in the CPA cohort was detected. CPA meningiomas showed chromosomal stability and were located mainly in the skull base. Ninety percent of CPA meningiomas were low-grade meningiomas and 63.4% were meningotheliomas. Half of our CPA cohort had microcystic components.

Conclusion

Our study shows that low-grade meningothelial meningiomas of the skull base are predominant in CPA meningiomas. We identified PIK3CA/AKT1 pathway as a hypothetical actor in onco-pharmacological interaction between meningiomas and CPA. This signaling pathway could be an interesting target for precision medicine trials in meningioma patients who have been subjected to CPA. Our results could invite the scientific community to review the current classification of meningiomas and to evolve toward more specific histomolecular classification.

Management of Cavernous Sinus Meningioma Presenting With Cerebrovascular Insufficiency Secondary to Cavernous Carotid Artery Occlusion: Report of 2 Cases

BACKGROUND

Surgical removal of cavernous sinus meningiomas is challenging and associated with high morbidities as a result of the anatomic location and the surrounding neurovascular structures that are often invaded or encased by the tumor. Advances in radiotherapy techniques have led to the adoption of more conservative approaches in the management of cavernous sinus meningioma. Internal carotid artery encasement and invasion has been documented in these cases; however, ischemic presentation secondary to internal carotid artery stenosis or occlusion by meningioma in the region of the cavernous sinus is rare, with only few cases reported in the literature.

OBJECTIVE

To report our surgical technique and experience with bypass grafting for cavernous sinus meningiomas that invade or narrow the internal carotid artery.

METHODS

We report 2 patients who presented with signs and symptoms attributed to cavernous carotid artery occlusion secondary to cavernous sinus meningioma in the last 5 yr. Both patients were treated with flow augmentation without surgical intervention for the cavernous sinus meningioma.

RESULTS

In both cases, the clinical and radiological signs of cerebrovascular insufficiency improved markedly, and the patients' tumors are currently being monitored.

CONCLUSION

Although the cerebrovascular insufficiency in this subset of patients is attributed to the occlusion of the cavernous carotid artery caused by the tumor, we propose treating those patients with flow augmentation first with or without radiation therapy when there is a clear imaging feature suggestive of meningioma in the absence of significant cranial nerve deficit.

High p-mTOR expression is associated with recurrence and shorter disease-free survival in atypical meningiomas

Due to their widely variable clinical behavior, the post-surgical treatment of atypical meningiomas is controversial. Therefore, prognostic factors able to identify high-risk cases, which may benefit from adjuvant treatments, are warranted. Mammalian target of rapamycin (mTOR) belongs to the PI3K-AKT pathway. Its phosphorylated form (p-mTOR Ser2448) is involved in cell growth, differentiation and tumorigenesis. The aim of this study was to evaluate p-mTOR Ser2448 expression and its eventual correlation with clinicopathological features, recurrence, or disease-free survival (DFS), in atypical meningiomas. p-mTOR immunohistochemical expression was analyzed in 48 atypical meningiomas and correlated with clinicopathological parameters and with DFS. Eighty-one percent of atypical meningiomas expressed p-mTOR Ser2448. High immuno-expression was significantly associated with recurrences (P = 0.01) and lower DFS (P = 0.01). The presence of brain invasion, high mitotic index plus sheeting, and Simpson grade were significant and independent prognostic variables at multivariate analysis. p-mTOR Ser2448 is expressed in atypical meningiomas. High expression predicts development of recurrences and shorter DFS in patients affected by these tumors. Since p-mTOR Ser2448 is a target of anti-neoplastic drugs, evaluation of its expression may be used, not only to identify atypical meningiomas at higher risk of recurrence, but also to select those to submit to adjuvant targeted chemotherapy.

Towards Molecular Classification of Meningioma: Evolving Treatment and Diagnostic Paradigms

Meningioma, a common primary brain tumor in adults, is graded based on World Health Organization criteria that rely on histology alone. This approach is unable to determine conclusively which tumors, especially benign or atypical, will recur. Molecular characterization of meningioma has identified genetic biomarkers that can predict tumor behavior. Only a few genetic changes are known to classify >85% of all meningioma and clinical trials using targeted therapy to genetic subtypes of meningioma are under way. Immunotherapy is also being trialed in treating high-grade and recurrent meningioma. This review summarizes recent developments characterizing meningioma using genetic and immunologic biomarkers and how these molecular tools may be integrated into existing care together with current World Health Organization grading to improve diagnosis, prognosis, and therapy.

Emerging Medical Treatments for Meningioma in the Molecular Era

Meningiomas are the most common type of primary central nervous system tumors. Approximately, 80% of meningiomas are classified by the World Health Organization (WHO) as grade I, and 20% of these tumors are grade II and III, considered high-grade meningiomas (HGMs). Clinical control of HGMs, as well as meningiomas that relapse after surgery, and radiation therapy is difficult, and novel therapeutic approaches are necessary. However, traditional chemotherapies, interferons, hormonal therapies, and other targeted therapies have so far failed to provide clinical benefit. During the last several years, next generation sequencing has dissected the genetic heterogeneity of meningioma and enriched our knowledge about distinct oncogenic pathways driving different subtypes of meningiomas, opening up a door to new personalized targeted therapies. Molecular classification of meningioma allows a new design of clinical trials that assign patients to corresponding targeted agents based on the tumor genetic subtypes. In this review, we will shed light on emerging medical treatments of meningiomas with a particular focus on the new targets identified with genomic sequencing that have led to clinical trials testing novel compounds. Moreover, we present recent development of patient-derived preclinical models that provide platforms for assessing targeted therapies as well as strategies with novel mechanism of action such as oncolytic viruses.

Loss of histone H3K27me3 identifies a subset of meningiomas with increased risk of recurrence

Epigenetic patterns on the level of DNA methylation have already been shown to separate clinically relevant subgroups of meningiomas. We here set out to identify potential prognostic implications of epigenetic modification on the level of histones with focus on H3K27 trimethylation (H3K27me3). H3K27me3 was assessed by immunohistochemistry on 232 meningiomas from 232 patients. In 194 cases, trimethylation was detected in tumor cells. In 25 cases, staining was limited to vessels while all tumor cells were negative. Finally, 13 cases yielded equivocal staining patterns. Reduced abundance of H3K27me3 in cases with staining limited to vessels was confirmed by mass spectrometry on a subset of cases. Lack of staining for H3K27me3 in all tumor cells was significantly associated with more rapid progression (p = 0.009). In line, H3K27me3-negative cases were associated with a DNA methylation pattern of the more aggressive types among the recently introduced DNA methylation groups. Also, NF2 and SUFU mutations were enriched among cases with complete lack of H3K27me3 staining in tumor cells (p < 0.0001 and p = 0.029, respectively). H3K27me3 staining pattern added significant prognostic insight into WHO grade II cases and in the compound subset of WHO grade I and II cases (p = 0.04 and p = 0.007, respectively). However, it did not further stratify within WHO grade III cases. Collectively, these data indicate that epigenetic modifications beyond DNA methylation are involved in the aggressiveness of meningioma. It also suggests that H3K27me3 immunohistochemistry might be a useful adjunct in meningioma diagnostics, particularly for cases with WHO grade II histology or at the borderline between WHO grade I and II.

Advances in meningioma genetics: novel therapeutic opportunities

Meningiomas currently are among the most frequent intracranial tumours. Although the majority of meningiomas can be cured by surgical resection, ∼20% of patients have an aggressive clinical course with tumour recurrence or progressive disease, resulting in substantial morbidity and increased mortality of affected patients. During the past 3 years, exciting new data have been published that provide insights into the molecular background of meningiomas and link sites of tumour development with characteristic histopathological and molecular features, opening a new road to novel and promising treatment options for aggressive meningiomas. A growing number of the newly discovered recurrent mutations have been linked to a particular clinicopathological phenotype. Moreover, the updated WHO classification of brain tumours published in 2016 has incorporated some of these molecular findings, setting the stage for the improvement of future therapeutic efforts through the integration of essential molecular findings. Finally, an additional potential classification of meningiomas based on methylation profiling has been launched, which provides clues in the assessment of individual risk of meningioma recurrence. All of these developments are creating new prospects for effective molecularly driven diagnosis and therapy of meningiomas.

UNBS5162 inhibits the proliferation of human A549 non-small-cell lung cancer cells by promoting apoptosis

Background

Lung cancer is one of the most frequently diagnosed malignancies in the world, thus developing novel anticancer reagents for lung cancer treatment is critical.

Methods

We performed cell counting kit‐8 and cell colony formation assays to investigate the role of UNBS5162 in the proliferation of A549 cells. Invasion and migration assays were applied to study the inhibitory effect of UNBS5162 on non‐small cell lung cancer cells. To detect the effect of UNBS5162 on A549 cell apoptosis, Annexin‐V fluorescein isothiocyanate and propidium iodide staining methods were used. Protein expression was analyzed using Western blot assay.

Results

UNBS5162 not only inhibited proliferation but also decreased invasion and migration in A549 cells. Most cells were intact (96.93%) under control conditions, but the number of intact cells decreased (84.8%) after 24 hours of treatment with UNBS5162, and the number of early and late apoptotic cells significantly increased (P < 0.05). Anti‐apoptotic protein Bcl‐2 expression in the UNBS5162 group was significantly decreased (P < 0.05), and expression of proapoptotic proteins Bim, Bax, and active caspase‐3 were significantly increased (P < 0.05) compared to the control. In the PI3K signaling pathway, phospo‐AKT and phospo‐mTOR levels were significantly decreased (P < 0.05), while S6K and Cyclin D1 protein levels were significantly decreased in UNBS5162 treated A549 cells (P < 0.05).

Conclusion

These findings suggest that UNBS5162 could inhibit A549 cell proliferation and metastasis by inhibiting PI3K pathway mediated apoptosis.