Chibawanye I. Ene

Epigenetic-Mediated Dysfunction of the Bone Morphogenetic Protein Pathway Inhibits Differentiation of Glioblastoma-Initiating Cells

Despite similarities between tumor-initiating cells with stem-like properties (TICs) and normal neural stem cells, we hypothesized that there may be differences in their differentiation potentials. We now demonstrate that both bone morphogenetic protein (BMP)-mediated and ciliary neurotrophic factor (CNTF)-mediated Jak/STAT-dependent astroglial differentiation is impaired due to EZH2-dependent epigenetic silencing of BMP receptor 1B (BMPR1B) in a subset of glioblastoma TICs. Forced expression of BMPR1B either by transgene expression or demethylation of the promoter restores their differentiation capabilities and induces loss of their tumorigenicity. We propose that deregulation of the BMP developmental pathway in a subset of glioblastoma TICs contributes to their tumorigenicity both by desensitizing TICs to normal differentiation cues and by converting otherwise cytostatic signals to proproliferative signals.

Effect of brain- and tumor-derived connective tissue growth factor on glioma invasion.

BACKGROUND Tumor cell invasion is the principal cause of treatment failure and death among patients with malignant gliomas. Connective tissue growth factor (CTGF) has been previously implicated in cancer metastasis and invasion in various tumors. We explored the mechanism of CTGF-mediated glioma cell infiltration and examined potential therapeutic targets. METHODS Highly infiltrative patient-derived glioma tumor-initiating or tumor stem cells (TIC/TSCs) were harvested and used to explore a CTGF-induced signal transduction pathway via luciferase reporter assays, chromatin immunoprecipitation (ChIP), real-time polymerase chain reaction, and immunoblotting. Treatment of TIC/TSCs with small-molecule inhibitors targeting integrin β1 (ITGB1) and the tyrosine kinase receptor type A (TrkA), and short hairpin RNAs targeting CTGF directly were used to reduce the levels of key protein components of CTGF-induced cancer infiltration. TIC/TSC infiltration was examined in real-time cell migration and invasion assays in vitro and by immunohistochemistry and in situ hybridization in TIC/TSC orthotopic xenograft mouse models (n = 30; six mice per group). All statistical tests were two-sided. RESULTS Treatment of TIC/TSCs with CTGF resulted in CTGF binding to ITGB1-TrkA receptor complexes and nuclear factor kappa B (NF-κB) transcriptional activation as measured by luciferase reporter assays (mean relative luciferase activity, untreated vs CTGF(200 ng/mL): 0.53 vs 1.87, difference = 1.34, 95% confidence interval [CI] = 0.69 to 2, P < .001). NF-κB activation resulted in binding of ZEB-1 to the E-cadherin promoter as demonstrated by ChIP analysis with subsequent E-cadherin suppression (fold increase in ZEB-1 binding to the E-cadherin promoter region: untreated + ZEB-1 antibody vs CTGF(200 ng/mL) + ZEB-1 antibody: 1.5 vs 6.4, difference = 4.9, 95% CI = 4.8 to 5.0, P < .001). Immunohistochemistry and in situ hybridization revealed that TrkA is selectively expressed in the most infiltrative glioma cells in situ and that the surrounding reactive astrocytes secrete CTGF. CONCLUSION A CTGF-rich microenvironment facilitates CTGF-ITGB1-TrkA complex activation in TIC/TSCs, thereby increasing the invasiveness of malignant gliomas.

Histone Demethylase Jumonji D3 (JMJD3) as a Tumor Suppressor by Regulating p53 Protein Nuclear Stabilization

Histone methylation regulates normal stem cell fate decisions through a coordinated interplay between histone methyltransferases and demethylases at lineage specific genes. Malignant transformation is associated with aberrant accumulation of repressive histone modifications, such as polycomb mediated histone 3 lysine 27 (H3K27me3) resulting in a histone methylation mediated block to differentiation. The relevance, however, of histone demethylases in cancer remains less clear. We report that JMJD3, a H3K27me3 demethylase, is induced during differentiation of glioblastoma stem cells (GSCs), where it promotes a differentiation-like phenotype via chromatin dependent (INK4A/ARF locus activation) and chromatin independent (nuclear p53 protein stabilization) mechanisms. Our findings indicate that deregulation of JMJD3 may contribute to gliomagenesis via inhibition of the p53 pathway resulting in a block to terminal differentiation.

Personalized medicine for gliomas.

Personalized medicine for cancer entails tailoring therapy for each patient based on unique features of the patients tumor; physiologic, molecular, genetic and epigenetic. Our ability to molecularly characterize tumor cells has increased dramatically and shown that there are significant differences between samples from patients with the same tumor type. Given this extensive variability in mutations and pathways driving tumors in patients, seeking a single bullet is an unrealistic approach for achieving a cure. In glioblastoma multiforme (GBM), the most common adult brain tumor, this inter-tumoral heterogeneity is further complicated by intra-tumoral heterogeneity within the tumor. This suggests that for personalized therapy to work for GBMs, pharmacologic agents would not only be tailored to target the differences from patient to patient but also the clonal diversity within each patients tumor. In this review, we provide a historical perspective on clinical trials for cancer. We also discuss the current state of molecular biology and immunology based strategies for personalized therapies for glioblastoma multiforme.

Timing of cranioplasty: a 10.75-year single-center analysis of 754 patients

OBJECTIVE Despite their technical simplicity, cranioplasty procedures carry high reported morbidity rates. The authors here present the largest study to date on complications after cranioplasty, focusing specifically on the relationship between complications and timing of the operation. METHODS The authors retrospectively reviewed all cranioplasty cases performed at Harborview Medical Center over the past 10.75 years. In addition to relevant clinical and demographic characteristics, patient morbidity and mortality data were abstracted from the electronic medical record. Cox proportional-hazards models were used to analyze variables potentially associated with the risk of infection, hydrocephalus, seizure, hematoma, and bone flap resorption. RESULTS Over the course of 10.75 years, 754 cranioplasties were performed at a single institution. Sixty percent of the patients who underwent these cranioplasties were male, and the median follow-up overall was 233 days. The 30-day mortality rate was 0.26% (2 cases, both due to postoperative epidural hematoma). Overall, 24.6% percent of the patients experienced at least 1 complication including infection necessitating explantation of the flap (6.6%), postoperative hydrocephalus requiring a shunt (9.0%), resorption of the flap requiring synthetic cranioplasty (6.3%), seizure (4.1%), postoperative hematoma requiring evacuation (2.3%), and other (1.6%). The rate of infection was significantly higher if the cranioplasty had been performed < 14 days after the initial craniectomy (p = 0.007, Holm-Bonferroni-adjusted p = 0.028). Hydrocephalus was significantly correlated with time to cranioplasty (OR 0.92 per 10-day increase, p < 0.001) and was most common in patients whose cranioplasty had been performed < 90 days after initial craniectomy. New-onset seizure, however, only occurred in patients who had undergone their cranioplasty > 90 days after initial craniectomy. Bone flap resorption was the least likely complication for patients whose cranioplasty had been performed between 15 and 30 days after initial craniectomy. Resorption was also correlated with patient age, with a hazard ratio of 0.67 per increase of 10 years of age (p = 0.001). CONCLUSIONS Cranioplasty performed between 15 and 30 days after initial craniectomy may minimize infection, seizure, and bone flap resorption, whereas waiting > 90 days may minimize hydrocephalus but may increase the risk of seizure.

Natural history of cerebral cavernous malformations

Cerebral cavernous malformations (CCM) are vascular abnormalities of the central nervous system with an incidence of 0.4-0.5% and an annual rate of hemorrhage ranging from 0.7% to 1%. Most lesions are located in the cerebral hemisphere but some occur in deeper locations such as the basal ganglia and pons. The most common symptoms during presentation are headache, seizures, and focal neurologic deficits. Surgery remains the most effective treatment modality for symptomatic CCM, while the management of incidental CCM remains controversial. Factors associated with increased risk of hemorrhage include being female and less than 40 years old. This finding, however, is not consistent in all natural history studies evaluated. During follow-up, the most important and consistent risk factor for rebleed was a prior hemorrhage. Here, we provide an indepth but concise review of the literature regarding the natural history of CCMs.

Spontaneous Hemorrhage from Central Nervous System Hemangioblastomas

OBJECTIVE Hemagioblastomas are highly vascular tumors that rarely present with hemorrhage. To date, the only factor reported to possibly influence the propensity of a tumor to bleed has been its size (>1.5 cm). Here, we present our series of hemorrhagic hemangioblastomas, which includes 2 very small tumors (<1.5 cm). We propose that other factors apart from size may predispose tumors to hemorrhage. METHODS We conducted a retrospective analysis of 55 cases of central nervous system hemangioblastomas operated on at Harborview Medical Hospital and the University of Washington between 2004 and 2014. Demographical and clinical data were collected and analyzed to determine factors that may predispose these tumors to hemorrhage. RESULTS Of 55 cases, only 3 patients presented with hemorrhage (5.5%). None of the patients were von Hippel-Lindau positive. Two of the hemorrhagic tumors were less than 1.5 cm, countering previous studies in which authors proposed that hemangioblastomas that are less than 1.5 cm have essentially no risk of hemorrhage. One tumor also rebled after preoperative embolization. CONCLUSIONS Our series suggests that small hemangioblastomas may represent a hemorrhagic risk. We speculate that other factors, such as genetic predisposition caused by single-nucleotide polymorphisms, may play a role in hemangiobalstomas that present with rupture.

Flow-Related Aneurysm within Glioblastoma: A Case Report and Review of Literature

BACKGROUND Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a median survival of 13 months despite surgery and chemoradiation. GBMs are often hypervascular tumors caused by abnormal oversecretion of growth factors such as vascular endothelial growth factor. These angiogenic factors are hypothesized to promote increased blood flow and possibly secondary changes to arterial walls, thus facilitating the formation of flow-related aneurysms. CASE DESCRIPTION A 59-year-old woman presented with headaches, confusion, nausea and emesis. Computed tomography and magnetic resonance imaging revealed a hypervascular lesion, likely high-grade glioma, in the right frontal lobe, with a dilated vessel within the tumor. Cerebral angiography demonstrated a flow-related aneurysm on the right frontopolar artery supplying the tumor. The aneurysm was embolized with coils and the patient later underwent craniotomy for near total resection of the lesion without complications. Final pathology returned GBM with dilated vessels noted. CONCLUSIONS Hypervascular lesions, such as GBMs, may be associated with flow-related aneurysms on feeding arteries, but aneurysms within the gross tumor are unusual. Although rare, this finding needs to be recognized on preoperative imaging before tumor resection to prevent potentially catastrophic intraoperative complications.

Treatment of Gliomas: How did we get here?

Over the past 30 years, the treatment of gliomas has become more multi-modality with clinical trials demonstrating that adjuvant chemo-radiation following surgery improves survival of patients. Unfortunately, this advance in therapeutic intervention has had a modest impact on patient survival, with only a 3–6 month improvement in survival during this time period. In this review, we discuss the progress made in each key aspect of glioma treatment; chemotherapy, surgery and radiation therapy. We present key clinical trials that were used as basis for current management guidelines for patients with gliomas. Ultimately, it is clear that future treatments of patients with gliomas will entail specific chronologic combinations of these three modalities in personalized regimens designed for individual patient tumor sub-type.

Nanoparticles That Reshape the Tumor Milieu Create a Therapeutic Window for Effective T-cell Therapy in Solid Malignancies

A major obstacle to the success rate of chimeric antigen receptor (CAR-) T-cell therapy against solid tumors is the microenvironment antagonistic to T cells that solid tumors create. Conventional checkpoint blockade can silence lymphocyte antisurvival pathways activated by tumors, but because they are systemic, these treatments disrupt immune homeostasis and induce autoimmune side effects. Thus, new technologies are required to remodel the tumor milieu without causing systemic toxicities. Here, we demonstrate that targeted nanocarriers that deliver a combination of immune-modulatory agents can remove protumor cell populations and simultaneously stimulate antitumor effector cells. We administered repeated infusions of lipid nanoparticles coated with the tumor-targeting peptide iRGD and loaded with a combination of a PI3K inhibitor to inhibit immune-suppressive tumor cells and an α-GalCer agonist of therapeutic T cells to synergistically sway the tumor microenvironment of solid tumors from suppressive to stimulatory. This treatment created a therapeutic window of 2 weeks, enabling tumor-specific CAR-T cells to home to the lesion, undergo robust expansion, and trigger tumor regression. CAR-T cells administered outside this therapeutic window had no curative effect. The lipid nanoparticles we used are easy to manufacture in substantial amounts, and we demonstrate that repeated infusions of them are safe. Our technology may therefore provide a practical and low-cost strategy to potentiate many cancer immunotherapies used to treat solid tumors, including T-cell therapy, vaccines, and BITE platforms.Significance: A new nanotechnology approach can promote T-cell therapy for solid tumors. Cancer Res; 78(13); 3718-30. ©2018 AACR.