Chromodomain Helicase DNA-Binding Protein 7 Is Suppressed in the Perinecrotic/Ischemic Microenvironment and Is a Novel Regulator of Glioblastoma Angiogenesis.

Tumorigenic and non-neoplastic tissue injury occurs via the ischemic microenvironment defined by low oxygen, pH, and nutrients due to blood supply malfunction. Ischemic conditions exist within regions of pseudopalisading necrosis, a pathological hallmark of glioblastoma (GBM), the most common primary malignant brain tumor in adults. To recapitulate the physiologic microenvironment found in GBM tumors and tissue injury, we developed an in vitro ischemic model and identified chromodomain helicase DNA-binding protein 7 (CHD7) as a novel ischemia-regulated gene. Point mutations in the CHD7 gene are causal in CHARGE syndrome (a developmental disorder causing coloboma, heart defects, atresia choanae, retardation of growth, and genital and ear anomalies) and interrupt the epigenetic functions of CHD7 in regulating neural stem cell maintenance and development. Using our ischemic system, we observed microenvironment-mediated decreases in CHD7 expression in brain tumor-initiating cells and neural stem cells. Validating our approach, CHD7 was suppressed in the perinecrotic niche of GBM patient and xenograft sections, and an interrogation of patient gene expression datasets determined correlations of low CHD7 with increasing glioma grade and worse patient outcomes. Segregation of GBM by molecular subtype revealed a novel observation that CHD7 expression is elevated in proneural versus mesenchymal GBM. Genetic targeting of CHD7 and subsequent gene ontology analysis of RNA sequencing data indicated angiogenesis as a primary biological function affected by CHD7 expression changes. We validated this finding in tube-formation assays and vessel formation in orthotopic GBM models. Together, our data provide further understanding of molecular responses to ischemia and a novel function of CHD7 in regulating angiogenesis in both neoplastic and non-neoplastic systems. Stem Cells 2019;37:453-462.

Characterization of iPSCs derived from low grade gliomas revealed early regional chromosomal amplifications during gliomagenesis.

INTRODUCTION: IDH1 mutation has been identified as an early genetic event driving low grade gliomas (LGGs) and it has been proven to exerts a powerful epigenetic effect. Cells containing IDH1 mutation are refractory to epigenetical reprogramming to iPSC induced by expression of Yamanaka transcription factors, a feature that we employed to study early genetic amplifications or deletions in gliomagenesis. METHODS: We made iPSC clones from freshly surgically resected IDH1 mutant LGGs by forced expression of Yamanaka transcription factors. We sequenced the IDH locus and analyzed the genetic composition of multiple iPSC clones by array-based comparative genomic hybridization (aCGH). RESULTS: We hypothesize that the primary cell pool isolated from LGG tumor contains a heterogeneous population consisting tumor cells at various stages of tumor progression including cells with early genetic lesions if any prior to acquisition of IDH1 mutation. Because cells containing IDH1 mutation are refractory to reprogramming, we predict that iPSC clones should originate only from LGG cells without IDH1 mutation, i.e. cells prior to acquisition of IDH1 mutation. As expected, we found that none of the iPSC clones contains IDH1 mutation. Further analysis by aCGH of the iPSC clones reveals that they contain regional chromosomal amplifications which are also present in the primary LGG cells. CONCLUSIONS: These results indicate that there exists a subpopulation of cells harboring gene amplification but without IDH1 mutation in the LGG primary cell pool. Further analysis of TCGA LGG database demonstrates that these regional chromosomal amplifications are also present in some cases of low grade gliomas indicating they are reoccurring lesions in glioma albeit at a low frequency. Taken together, these data suggest that regional chromosomal alterations may exist prior to the acquisition of IDH mutations in at least some cases of LGGs.

Hu antigen R (HuR) multimerization contributes to glioma disease progression.

Among primary brain cancers, gliomas are the most deadly and most refractory to current treatment modalities. Previous reports overwhelmingly support the role of the RNA-binding protein Hu antigen R (HuR) as a positive regulator of glioma disease progression. HuR expression is consistently elevated in tumor tissues, and a cytoplasmic localization appears essential for HuR-dependent oncogenic transformation. Here, we report HuR aggregation (multimerization) in glioma and the analysis of this tumor-specific HuR protein multimerization in clinical brain tumor samples. Using a split luciferase assay, a bioluminescence resonance energy transfer technique, and site-directed mutagenesis, we examined the domains involved in HuR multimerization. Results obtained with the combination of the split HuR luciferase assay with the bioluminescence resonance energy transfer technique suggested that multiple (at least three) HuR molecules come together during HuR multimerization in glioma cells. Using these data, we developed a model of HuR multimerization in glioma cells. We also demonstrate that exposing glioma cells to the HuR inhibitor tanshinone group compound 15,16-dihydrotanshinone-I or to the newly identified compound 5 disrupts HuR multimerization modules and reduces tumor cell survival and proliferation. In summary, our findings provide new insights into HuR multimerization in glioma and highlight possible pharmacological approaches for targeting HuR domains involved in cancer cell-specific multimerization.

Key rates for the grades and transformation ability of glioma: model simulations and clinical cases.

Tumor progression to higher grade is a fundamental property of cancer. The malignant advancement of the pathological features may either develop during the later stages of cancer growth (natural evolution) or it may necessitate new mutations or molecular events that alter the rates of growth, dispersion, or neovascularization (transformation). Here, we model the pathological and radiological features of grades 2-4 gliomas at the times of diagnosis and death and study grade development and the progression to higher grades. We perform a retrospective review of clinical cases based on model predictions. Simulations uncover two unusual patterns of glioma progression, which are supported by clinical cases: (1) some grades 2 and 3 gliomas lack the ability of progression to higher grades, and (2) grade 3 glioma may evolve to GBM in a few weeks. All 13 gliomas that recurred at the same grade carry either the IDH1-R132H or the ATRX mutation. All (five of five) grade 3 tumors are 1p/19q co-deleted, IDH1-R132H mutated and ATRX wt. Furthermore, three of seven grade 2 gliomas are both IDH1-R132H mutated and ATRX mutated. Simulations replicate the good prognosis of secondary GBM. The results support the hypothesis that constant rates of dispersion, proliferation, and angiogenesis prescribe either a natural evolution or the inability to progress to higher grades. Furthermore, the accrual of molecular events that change a tumor's ability to infiltrate, proliferate or neovascularize may transform the glioma either into a more aggressive tumor at the same grade or elevate its grade.

Case 212: chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids.

History A previously healthy 23-year-old white man presented to the emergency department of our hospital with a 2-month history of dysarthria, progressively worsening vertigo, and difficulty walking. A diagnosis of retinitis pigementosa was made in this patient's childhood. He did not have any history of congenital syphilis. He did not have a history of nausea or vomiting, fever, weight loss, headache, photophobia, seizure, extremity weakness, or sensory disturbance. Physical examination revealed dysarthria, dysmetria, and ataxia. Kernig and Brudzinski signs were absent, and pathergy test results were negative. Laboratory evaluation revealed normal complete and differential blood counts and normal serum chemistry, including a normal serum angiotensin-converting enzyme level. Analysis of his serum was negative for antinuclear antibody (or ANA), cytoplasmic antineutrophil cvtoplasmic antibody (or cANCA), Sjögren syndrome antigens A and B (SS-A and SS-B, respectively), antitissue transglutaminase and antiendomysial antibodies, and paraneoplastic profile. Serum analysis was also negative for human immunodeficiency virus type 1 and type 2 RNA, Venereal Disease Research Laboratory (VDRL) test, rapid plasma regain (RPR), and fluorescent treponemal antibody absorption. Cerebrospinal fluid (CSF) analysis revealed clear fluid, a normal glucose level (64 mg/dL [3.6 mmol/L]; normal range, 40-70 mg/dL [2.2-3.9 mmol/L]), an elevated protein level (97 mg/dL; normal range, 12-60 mg/dL), and an elevated white blood cell count (7/mm(3) [0.007 ×10(9)/L] in tube 1 and 17/mm(3) [0.017 × 10(9)/L] in tube 2) with 84% lymphocytes. CSF immunoglobulin G level was elevated (30.1 mg/dL; normal, <5.9 mg/dL); however, there were no oligoclonal bands. Gram staining, acid-fast staining, and lactic acid, cryptococcal antigen, histoplasma antigen, herpes simplex virus polymerase chain reaction, VDRL, and RPR test results for CSF were negative. CSF did not grow any bacteria, fungus, or acid-fast bacillus at culture. CSF flow cytometry did not reveal a monoclonal lymphoid population. Initial imaging included brain magnetic resonance (MR) imaging. Computed tomography (CT) images of the chest, abdomen, and pelvis were normal (not shown). The patient's clinical symptoms and imaging findings responded to treatment with a high dose of oral steroids. However, the patient's symptoms exhibited clinical and radiologic progression after several attempts to taper the steroid dose.

Prospective biomarker study in newly diagnosed glioblastoma: Cyto-C clinical trial.

BACKGROUND: Glioblastoma (GBM) has a 5-year survival rate of 3%-5%. GBM treatment includes maximal resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ). Cytochrome C oxidase (CcO) is a mitochondrial enzyme involved in the mechanism of resistance to TMZ. In a prior retrospective trial, CcO activity in GBMs inversely correlated with clinical outcome. The current Cyto-C study was designed to prospectively evaluate and validate the prognostic value of tumor CcO activity in patients with newly diagnosed primary GBM, and compared to the known prognostic value of MGMT promoter methylation status. METHODS: This multi-institutional, blinded, prospective biomarker study enrolled 152 patients with newly diagnosed GBM who were to undergo surgical resection and would be candidates for standard of care. The primary end point was overall survival (OS) time, and the secondary end point was progression-free survival (PFS) time. Tumor CcO activity and MGMT promoter methylation status were assayed in a centralized laboratory. RESULTS: OS and PFS did not differ by high or low tumor CcO activity, and the prognostic validity of MGMT promoter methylation was confirmed. Notably, a planned exploratory analysis suggested that the combination of low CcO activity and MGMT promoter methylation in tumors may be predictive of long-term survival. CONCLUSIONS: Tumor CcO activity alone was not confirmed as a prognostic marker in GBM patients. However, the combination of low CcO activity and methylated MGMT promoter may reveal a subgroup of GBM patients with improved long-term survival that warrants further evaluation. Our work also demonstrates the importance of performing large, multi-institutional, prospective studies to validate biomarkers. We also discuss lessons learned in assembling such studies.

Rare Ameloblastic Carcinoma Metastasis to the Cervical Spine: A Case Report.

BACKGROUND AND IMPORTANCE: Ameloblastic carcinoma (AC) is a malignant neoplasm of epithelial origin that typically arises from the mandible or maxilla. It represents approximately 2% of all odontogenic tumors. Gross total resection is the surgical goal given AC's aggressiveness and propensity for recurrence. We present the first reported AC metastasis to the cervical spine. CLINICAL PRESENTATION: A 61-yr-old African American female with a history of AC of bilateral mandibles and lung metastases presented with neck pain and right arm weakness progressive over several months. Cervical spine imaging demonstrated a cervical 3 pathological fracture with severe anterior vertebral body compression and resultant cervical 2-3 kyphotic deformity and bony retropulsion causing severe cord compression. The patient underwent a cervical 3 corpectomy and cervical 2-4 anterior fixation followed by a cervical 3 laminectomy and cervical 2-5 dorsal internal fixation and fusion. Postoperatively, the patient's neurological exam remained stable and imaging showed improved spinal alignment and appropriate anterior and posterior instrumentation. Unfortunately, the patient thereafter suffered a decline in performance status and progression of lung metastatic disease. Her oncology team is considering chemotherapy and stereotactic radiosurgery, but her prognosis remains grim. CONCLUSION: AC is a rare and aggressive pathology with a poor prognosis despite multimodal therapy. We present the first case of AC metastatic spread to the spine. We aim to bring this pathology to the attention of our worldwide neurosurgical colleagues and share our surgical approach and multidisciplinary management to assist those who may encounter this pathology in the future.

Cerebellar talcosis following posterior reversible encephalopathy syndrome in an intravenous methamphetamine abuser.

BACKGROUND: Intravenous (IV) methamphetamine abuse is associated with a variety of short- and long-term effects on the nervous system, some of which have yet to be fully elucidated. One known systemic complication that has not been described in nervous system tissues is the deposition of substrate crystals contained in injectable drugs. CASE DESCRIPTION: An unusual case is presented of a 35-year-old active IV methamphetamine abuser with posterior reversible encephalopathy syndrome (PRES) who subsequently developed multifocal bilateral cerebellar enhancing lesions and leptomeningeal enhancement due to biopsy-proven crystalline deposits. CONCLUSION: Although large crystalline substances will not normally penetrate the blood-brain barrier (BBB), during a state of BBB compromise such as with PRES, talc deposition may occur in the central nervous system.

RANKLed by the Complexity of Signaling in Breast Cancer Metastasis to the Brain.

BACKGROUND: Receptor activator of nuclear factor κB (RANK) and its ligand, RANKL, are essential for mammary gland development and play a vital role in breast carcinogenesis. RANKL-RANK signaling also drives thermoregulation and modulates inflammatory activation in the brain. The expression of RANKL in primary breast cancer (BC) has been negatively associated with brain metastases, while significantly higher levels of RANK are seen in BC with brain metastases. We examined the expression of RANK and RANKL in BC metastasis to the brain. PATIENTS AND METHODS: We examined the expression of RANK and RANKL in 40 cases of BC metastasis to the brain. RESULTS: RANK was variably expressed in BC cells but minimally expressed in the adjacent brain parenchyma. In contrast, the expression of RANKL was minimal in metastatic BC but highly variable in tumoral stroma. RANKL expression in normal brain stroma obtained during autopsy was negligible. Histologic grade and BC subtypes were not significantly associated with RANK expression in metastatic BC. A significant negative correlation between RANK in metastatic BC and RANKL in tumoral stroma was identified (P < .001). CONCLUSION: RANK expressed by primary BC and RANKL detected in the tumor microenvironment together participate in cancer development, while the same principle may operate at distant sites. Further investigation is necessary to provide additional insight into the role of the RANKL-RANK pathway in BC progression and to investigate the potential efficacy of therapeutic strategies targeting these molecules in BC metastasis to the brain.