Molecular profiling of pediatric meningiomas shows tumor characteristics distinct from adult meningiomas

In contrast to adults, meningiomas are uncommon tumors in childhood and adolescence. Whether adult and pediatric meningiomas differ on a molecular level is unclear. Here we report detailed genomic analyses of 37 pediatric meningiomas by sequencing and DNA methylation profiling. Histologically, the series was dominated by meningioma subtypes with aggressive behavior, with 70% of patients suffering from WHO grade II or III meningiomas. The most frequent cytogenetic aberrations were loss of chromosomes 22 (23/37 [62%]), 1 (9/37 [24%]), 18 (7/37 [19%]), and 14 (5/37 [14%]). Tumors with NF2 alterations exhibited overall increased chromosomal instability. Unsupervised clustering of DNA methylation profiles revealed separation into three groups: designated group 1 composed of clear cell and papillary meningiomas, whereas group 2A comprised predominantly atypical meningiomas and group 2B enriched for rare high-grade subtypes (rhabdoid, chordoid). Meningiomas from NF2 patients clustered exclusively within groups 1 and 2A. When compared with a dataset of 105 adult meningiomas, the pediatric meningiomas largely grouped separately. Targeted panel DNA sequencing of 34 tumors revealed frequent NF2 alterations, while other typical alterations found in adult non-NF2 tumors were absent. These data demonstrate that pediatric meningiomas are characterized by molecular features distinct from adult tumors

Filamin A Phosphorylation at Serine 2152 by the Serine/Threonine Kinase Ndr2 Controls TCR-Induced LFA-1 Activation in T Cells

The integrin LFA-1 (CD11a/CD18) plays a critical role in the interaction of T cells with antigen presenting cells (APCs) to promote lymphocyte differentiation and proliferation. This integrin can be present either in a closed or in an open active conformation and its activation upon T-cell receptor (TCR) stimulation is a critical step to allow interaction with APCs. In this study we demonstrate that the serine/threonine kinase Ndr2 is critically involved in the initiation of TCR-mediated LFA-1 activation (open conformation) in T cells. Ndr2 itself becomes activated upon TCR stimulation and phosphorylates the intracellular integrin binding partner Filamin A (FLNa) at serine 2152. This phosphorylation promotes the dissociation of FLNa from LFA-1, allowing for a subsequent association of Talin and Kindlin-3 which both stabilize the open conformation of LFA-1. Our data suggest that Ndr2 activation is a crucial step to initiate TCR-mediated LFA-1 activation in T cells

Analysis of Phosphorylation-dependent Protein Interactions of Adhesion and Degranulation Promoting Adaptor Protein (ADAP) Reveals Novel Interaction Partners Required for Chemokine-directed T cell Migration

Stimulation of T cells leads to distinct changes of their adhesive and migratory properties. Signal propagation from activated receptors to integrins depends on scaffolding proteins such as the adhesion and degranulation promoting adaptor protein (ADAP)1. Here we have comprehensively investigated the phosphotyrosine interactome of ADAP in T cells and define known and novel interaction partners of functional relevance. While most phosphosites reside in unstructured regions of the protein, thereby defining classical SH2 domain interaction sites for master regulators of T cell signaling such as SLP76, Fyn-kinase, and NCK, other binding events depend on structural context. Interaction proteomics using different ADAP constructs comprising most of the known phosphotyrosine motifs as well as the structured domains confirm that a distinct set of proteins is attracted by pY571 of ADAP, including the ζ-chain-associated protein kinase of 70 kDa (ZAP70). The interaction of ADAP and ZAP70 is inducible upon stimulation either of the T cell receptor (TCR) or by chemokine. NMR spectroscopy reveals that the N-terminal SH2 domains within a ZAP70-tandem-SH2 construct is the major site of interaction with phosphorylated ADAP-hSH3N and microscale thermophoresis (MST) indicates an intermediate binding affinity (Kd = 2.3 μM). Interestingly, although T cell receptor dependent events such as T cell/antigen presenting cell (APC) conjugate formation and adhesion are not affected by mutation of Y571, migration of T cells along a chemokine gradient is compromised. Thus, although most phospho-sites in ADAP are linked to T cell receptor related functions we have identified a unique phosphotyrosine that is solely required for chemokine induced T cell behavior

AKT1E17K-mutated meningioma cell lines respond to treatment with the AKT inhibitor AZD5363

Aims: Meningiomas are the most frequent primary brain tumours. Recently, knowledge about the molecular drivers underlying aggressive meningiomas has been expanded. A hotspot mutation in the AKT1 gene (AKT1E17K), which is found in meningiomas at the convexity and especially at the skull base, has been associated with earlier tumour recurrence. Methods: Here, we analysed the effects of the AKT1E17K mutation and treatment response to the Akt inhibitor AZD5363 in transgenic meningioma cell clones and mouse xenografts modelling convexity or skull base meningiomas. Results: We show that the AKTE17K mutation significantly enhances meningioma cell proliferation and colony size in vitro, resulting in significantly shortened survival times of mice carrying convexity or skull base AKT1E17K xenografts. Treatment of mutant cells or xenografts (150 mg/kg/d) with AZD5363 revealed a significant decrease in cell proliferation and colony size and a prolongation of mouse survival. Western blots revealed activation of AKT1 kinase (phosphorylation at Ser273 and Thr308) by the E17K mutation in human meningioma samples and in our in vitro and in vivo models. Conclusions: Our data suggest that AKT1E17K mutated meningiomas are a promising selective target for AZD5363.Projekt DEAL 202

Clinical Characteristics and Magnetic Resonance Imaging-Based Prediction of the KLF4(K409Q) Mutation in Meningioma

BACKGROUND: Meningioma is the most common primary brain tumor in adults. In recent years, several non-neurofibromin 2 mutations, i.e., AKT1, SMO, TRAF7, and KLF4 mutations, specific for meningioma have been identified. This study aims to analyze the clinical impact and imaging characteristics of the KLF4(K409Q) mutation in meningioma. METHODS: Clinical, neuropathologic, and imaging data of 170 patients who underwent meningioma resection between 2013 and 2018 were retrospectively collected and tumors were analyzed for the presence of the KLF4(K409Q) mutation. We collected imaging characteristics, performed volumetric analysis of tumor size and peritumoral edema (PTBE), and calculated the edema index (EI, i.e., ratio of PTBE to tumor volume). Receiver operating characteristic curve analysis was performed to identify cut-off EI values to predict the mutational status of KLF4. RESULTS: Eighteen (10.6%) of the meningiomas carried the KLF4(K409Q) mutation; these were significantly associated with a secretory subtype (P < 0.001) and sphenoid wing location (P = 0.029). Smaller tumor size (P = 0.007), an increased PTBE (P = 0.012), and an increased EI (P = 0.001) proved to be significantly associated with the KLF4(K409Q) mutation. In receiver operating characteristic curve analysis, EI predicted the KLF4(K409Q) mutation with an area under the curve of 0.728 (P = 0.0016). CONCLUSIONS: The KLF4(K409Q) mutation is associated with a distinct small tumor subtype, prone to substantial PTBE. EI is a reliable parameter to predict the KLF4(K409Q) mutation in meningioma, thus providing a tool for improvement of pre- and perioperative medical management

Frequency of actionable molecular drivers in lung cancer patients with precocious brain metastases

Brain metastases frequently occur during the course of disease in patients suffering from lung cancer. Occasionally, neurological symptoms caused by brain metastases (BM) might represent the first sign of systemic tumor disease (so called precocious metastases), leading to the detection of the primary lung tumor. The biological basis of precocious BM is largely unknown, and treatment options are not well established for this subgroup of patients. Therefore, we retrospectively analyzed 33 patients (24 non-small cell lung cancer (NSCLC)), 9 small cell lung cancer (SCLC)) presenting with precocious BM focusing on molecular alterations potentially relevant for the tumor's biology and treatment. We found five FGFR1 amplifications (4 adenocarcinoma, 1 SCLC) among 31 analyzed patients (16.1%), eight MET amplifications among 30 analyzed tumors (7 NSCLC, 1 SCLC; 26.7%), three EGFR mutations within 33 patients (all adenocarcinomas, 9.1%), and five KRAS mutations among 32 patients (all adenocarcinomas; 15.6%). No ALK, ROS1 or RET gene rearrangements were detected. Our findings suggest that patients with precocious BM of lung cancer harbor EGFR mutations, MET amplifications or FGFR1 amplifications as potential targeted treatment options

KLF4(K409Q)-mutated meningiomas show enhanced hypoxia signaling and respond to mTORC1 inhibitor treatment

Meningioma represents the most common primary brain tumor in adults. Recently several non-NF2 mutations in meningioma have been identified and correlated with certain pathological subtypes, locations and clinical observations. Alterations of cellular pathways due to these mutations, however, have largely remained elusive. Here we report that the Krueppel like factor 4 (KLF4)-K409Q mutation in skull base meningiomas triggers a distinct tumor phenotype. Transcriptomic analysis of 17 meningioma samples revealed that KLF4(K409Q) mutated tumors harbor an upregulation of hypoxia dependent pathways. Detailed in vitro investigation further showed that the KLF4(K409Q) mutation induces HIF-1 alpha through the reduction of prolyl hydroxylase activity and causes an upregulation of downstream HIF-1 alpha targets. Finally, we demonstrate that KLF4(K409Q) mutated tumors are susceptible to mTOR inhibition by Temsirolimus. Taken together, our data link the KLF4(K409Q) mediated upregulation of HIF pathways to the clinical and biological characteristics of these skull base meningiomas possibly opening new therapeutic avenues for this distinct meningioma subtype

Molecular profiling of pediatric meningiomas shows tumor characteristics distinct from adult meningiomas.

In contrast to adults, meningiomas are uncommon tumors in childhood and adolescence. Whether adult and pediatric meningiomas differ on a molecular level is unclear. Here we report detailed genomic analyses of 37 pediatric meningiomas by sequencing and DNA methylation profiling. Histologically, the series was dominated by meningioma subtypes with aggressive behavior, with 70% of patients suffering from WHO grade II or III meningiomas. The most frequent cytogenetic aberrations were loss of chromosomes 22 (23/37 [62%]), 1 (9/37 [24%]), 18 (7/37 [19%]), and 14 (5/37 [14%]). Tumors with NF2 alterations exhibited overall increased chromosomal instability. Unsupervised clustering of DNA methylation profiles revealed separation into three groups: designated group 1 composed of clear cell and papillary meningiomas, whereas group 2A comprised predominantly atypical meningiomas and group 2B enriched for rare high-grade subtypes (rhabdoid, chordoid). Meningiomas from NF2 patients clustered exclusively within groups 1 and 2A. When compared with a dataset of 105 adult meningiomas, the pediatric meningiomas largely grouped separately. Targeted panel DNA sequencing of 34 tumors revealed frequent NF2 alterations, while other typical alterations found in adult non-NF2 tumors were absent. These data demonstrate that pediatric meningiomas are characterized by molecular features distinct from adult tumors