Amade Bregy

The bromodomain protein BRD4 controls HOTAIR, a long noncoding RNA essential for glioblastoma proliferation

Significance Glioblastoma Multiforme (GBM) is the most common and deadliest primary brain tumor in adults. As the median survival is approximately 14 mo there is an urgent need for novel therapies. Epigenetic modulators such as bromodomain and extraterminal (BET) proteins are important therapeutic targets in GBM. Bromodomain inhibitors (including I-BET151) suppress proliferation by repressing oncogenes and inducing tumor suppressor genes through unidentified pathways. Here we demonstrate that HOTAIR (HOX transcript antisense RNA) is overexpressed in GBM, where it is crucial to sustain tumor cell proliferation, and that inhibition of HOTAIR by I-BET151 is necessary to induce cell cycle arrest in GBM cells. Our study outlines the mechanism of action underlying the antiproliferative activity of I-BET151, showing for the first time, to our knowledge, that the oncogenic long noncoding RNA HOTAIR is a major target. Bromodomain and extraterminal (BET) domain proteins have emerged as promising therapeutic targets in glioblastoma and many other cancers. Small molecule inhibitors of BET bromodomain proteins reduce expression of several oncogenes required for Glioblastoma Multiforme (GBM) progression. However, the mechanism through which BET protein inhibition reduces GBM growth is not completely understood. Long noncoding RNAs (lncRNAs) are important epigenetic regulators with critical roles in cancer initiation and malignant progression, but mechanistic insight into their expression and regulation by BET bromodomain inhibitors remains elusive. In this study, we used Helicos single molecule sequencing to comprehensively profile lncRNAs differentially expressed in GBM, and we identified a subset of GBM-specific lncRNAs whose expression is regulated by BET proteins. Treatment of GBM cells with the BET bromdomain inhibitor I-BET151 reduced levels of the tumor-promoting lncRNA HOX transcript antisense RNA (HOTAIR) and restored the expression of several other GBM down-regulated lncRNAs. Conversely, overexpression of HOTAIR in conjunction with I-BET151 treatment abrogates the antiproliferative activity of the BET bromodomain inhibitor. Moreover, chromatin immunoprecipitation analysis demonstrated binding of Bromodomain Containing 4 (BRD4) to the HOTAIR promoter, suggesting that BET proteins can directly regulate lncRNA expression. Our data unravel a previously unappreciated mechanism through which BET proteins control tumor growth of glioblastoma cells and suggest that modulation of lncRNA networks may, in part, mediate the antiproliferative effects of many epigenetic inhibitors currently in clinical trials for cancer and other diseases.

The role of Gliadel wafers in the treatment of high-grade gliomas

Glioblastoma multiforme (GBM) is the most aggressive brain tumor. Standard treatment includes surgery, radiation and chemotherapy. Prognosis is dismal with an average survival of approximately 1 year. Gliadel wafers are one treatment option, working as a source for local chemotherapy delivery. Their use is controversial with questionable survival benefit and potential side effects. We reviewed the literature in an effort to clarify their role in the treatment of high-grade gliomas. A systematic PubMed search was performed using the keywords ‘Gliadel’, ‘carmustine’ or ‘BCNU wafers’ in newly diagnosed high-grade glioma patients. Treatment regimen, and median survival were analyzed. Adverse event ratio was calculated by computing the number of adverse events in a study per patient receiving carmustine wafers. Nineteen studies with 795 patients were included in our review. Survival was 8.7–22.6 months with a mean overall survival (OS) of 16.2 months (control survival is approximately 14 months with surgery and adjuvant chemoradiotherapy). Adverse event ratio using Gliadel wafersin control group. Complication rate was 42.7%. Gliadel wafers may marginally increase survival and local control in newly diagnosed GBM patients but are associated with a high complication rate; therefore, we do not recommend using Gliadel wafers in patients with GBM. Further research may be warranted once a safer alternative to Gliadel wafers has been introduced.

The role of radiosurgery to the tumor bed after resection of brain metastases.

BACKGROUND Optimal postoperative management paradigm for brain metastases remains controversial. OBJECTIVE To conduct a systematic review of the literature to understand the role of postoperative stereotactic radiosurgery after resection of brain metastases. METHODS We performed a MEDLINE search of the literature to identify series of patients with brain metastases treated with stereotactic radiosurgery after surgical resection. Outcomes including overall survival, local control, distant intracranial failure, and salvage therapy use were recorded. Patient, tumor, and treatment factors were correlated with outcomes through the use of the Pearson correlation and 2-way Student t test as appropriate. RESULTS Fourteen studies involving 629 patients were included. Median survival for all studies was 14 months. Local control was correlated with the median volume treated with radiosurgery (r = -0.766, P < .05) and with the rate of gross total resection (r = .728, P < .03). Mean crude local control was 83%; 1-year local control was 85%. Distant intracranial failure occurred in 49% of cases, and salvage whole-brain radiation therapy was required in 29% of cases. Use of a radiosurgical margin did not lead to increased local control or overall survival. CONCLUSION Our systematic review supports the use of radiosurgery as a safe and effective strategy for adjuvant treatment of brain metastases, particularly when gross total resection has been achieved. With all limitations of comparisons between studies, no increase in local recurrence or decrease in overall survival compared with rates with adjuvant whole-brain radiation therapy was found.

Active immunotherapy using dendritic cells in the treatment of glioblastoma multiforme

OBJECTIVE Glioblastoma multiforme, the most common malignant brain tumor still has a dismal prognosis with conventional treatment. Therefore, it is necessary to explore new and/or adjuvant treatment options to improve patient outcomes. Active immunotherapy is a new area of research that may be a successful treatment option. The focus is on vaccines that consist of antigen presenting cells (APCs) loaded with tumor antigen. We have conducted a systematic review of prospective studies, case reports and clinical trials. The goal of this study was to examine the efficacy and safety in terms of complications, median overall survival (OS), progression free survival (PFS) and quality of life. METHODS A PubMed search was performed to include all relevant studies that reported the characteristics, outcomes and complications of patients with GBM treated with active immunotherapy using dendritic cells. Reported parameters were immune response, radiological findings, median PFS and median OS. Complications were categorized based on association with the craniotomy or with the vaccine itself. RESULTS A total of 21 studies with 403 patients were included in our review. Vaccination with dendritic cells (DCs) loaded with autologous tumor cells resulted in increased median OS in patients with recurrent GBM (71.6-138.0 wks) as well as those newly diagnosed (65.0-230.4 wks) compared to average survival of 58.4 wks. CONCLUSIONS Active immunotherapy, specifically with autologous DCs loaded with autologous tumor cells, seems to have the potential of increasing median OS and prolonged tumor PFS with minimal complications. Larger clinical trials are needed to show the potential benefits of active immunotherapy.

Awake craniotomy for brain tumor resection: The rule rather than the exception?

Objective: Awake craniotomy (AC) has seen an expanded role in brain tumor surgery over the past few decades. AC allows intraoperative cortical mapping and the continuous assessment of neurophysiological parameters, which are otherwise unattainable under general anesthesia (GA). The ability of AC to analyze eloquent brain areas makes it a powerful method for reducing the risks associated with tumor resection, especially in motor and language cortex. We present a review of the literature to examine the benefits and limits of using AC over GA. Methods: A literature search was performed using the Medline and PubMed databases from 1970 and 2012 that compared craniotomy for tumor resection under GA and AC. Data of interest included length of hospital stay, operating time, extent of resection, and neurological sequelae. Results: A total of 8 studies with 951 patients (411 utilizing AC and 540 utilizing GA) were included in this review. Our interpretation of the literature suggests that AC (4 d, n=110) results in a shorter hospital stay than GA (9 d, n=116). Mean extent of resection was slightly less under awake conditions (41%, n=321) versus GA (44%, n=444), and postoperative deficits were less frequent under awake conditions (7%, n=411) versus GA (23%, n=520). Surgery time was slightly less in the AC group (165 min, n=324) versus GA (168 min, n=477). Conclusions: Given the effectiveness of AC for resection of eloquent tumors, the data suggests an expanded role for AC in brain tumor surgery regardless of tumor location.

Epigenetic pathways and glioblastoma treatment

Glioblastoma multiforme (GBM) is the most common malignant adult brain tumor. Standard GBM treatment includes maximal safe surgical resection with combination radiotherapy and adjuvant temozolomide (TMZ) chemotherapy. Alarmingly, patient survival at five-years is below 10%. This is in part due to the invasive behavior of the tumor and the resulting inability to resect greater than 98% of some tumors. In fact, recurrence after such treatment may be inevitable, even in cases where gross total resection is achieved. The Cancer Genome Atlas (TCGA) research network performed whole genome sequencing of GBM tumors and found that GBM recurrence is linked to epigenetic mechanisms and pathways. Central to these pathways are epigenetic enzymes, which have recently emerged as possible new drug targets for multiple cancers, including GBM. Here we review GBM treatment, and provide a systems approach to identifying epigenetic drivers of GBM tumor progression based on temporal modeling of putative GBM cells of origin. We also discuss advances in defining epigenetic mechanisms controlling GBM initiation and recurrence and the drug discovery considerations associated with targeting epigenetic enzymes for GBM treatment.

Predictors of Long-Term Survival in Patients With Glioblastoma Multiforme: Advancements From the Last Quarter Century

Over the last quarter century there has been significant progress toward identifying certain characteristics and patterns in GBM patients to predict survival times and outcomes. We sought to identify clinical predictors of survival in GBM patients from the past 24 years. We examined patient survival related to tumor locations, surgical treatment, postoperative course, radiotherapy, chemotherapy, patient age, GBM recurrence, imaging characteristics, serum, and molecular markers. We present predictors that may increase, decrease, or play no significant role in determining a GBM patients long-term survival or affect the quality of life.

Activation of NF-κB Mediates Astrocyte Swelling and Brain Edema in Traumatic Brain Injury

Brain edema and associated increased intracranial pressure are major consequences of traumatic brain injury (TBI). While astrocyte swelling (cytotoxic edema) represents a major component of the brain edema in the early phase of TBI, its mechanisms are unclear. One factor known to be activated by trauma is nuclear factor-κB (NF-κB). Because this factor has been implicated in the mechanism of cell swelling/brain edema in other neurological conditions, we examined whether NF-κB might also be involved in the mediation of post-traumatic astrocyte swelling/brain edema. Here we show an increase in NF-κB activation in cultured astrocytes at 1 and 3 h after trauma (fluid percussion injury, FPI), and that BAY 11-7082, an inhibitor of NF-κB, significantly blocked the trauma-induced astrocyte swelling. Increased activities of nicotinamide adenine dinucleotide phosphate-oxidase and the Na(+), K(+), 2Cl(-) cotransporter were also observed in cultured astrocytes after trauma, and BAY 11-7082 reduced these effects. We also examined the role of NF-κB in the mechanism of cell swelling by using astrocyte cultures derived from transgenic (Tg) mice with a functional inactivation of astrocytic NF-κB. Exposure of cultured astrocytes from wild-type mice to in vitro trauma (3 h) caused a significant increase in cell swelling. By contrast, traumatized astrocyte cultures derived from NF-κB Tg mice showed no swelling. We also found increased astrocytic NF-κB activation and brain water content in rats after FPI, while BAY 11-7082 significantly reduced such effects. Our findings strongly suggest that activation of astrocytic NF-κB represents a key element in the process by which cytotoxic brain edema occurs after TBI.

The role of whole-brain radiation therapy after stereotactic radiation surgery for brain metastases.

The benefit of whole-brain radiation therapy (WBRT) following stereotactic radiation surgery (SRS) for brain metastases is controversial. We conducted a systematic analysis of published literature to explore the outcome of brain metastases treated with SRS and WBRT versus SRS alone using PubMed and MEDLINE. Outcomes including survival, control, salvage therapy, and other quality of life measures were reported. Three randomized controlled trials involving 389 patients with 1 to 4 brain metastases were selected. In 2 of these trials (n = 190), the mean 1-year survival was 33.2% for SRS + WBRT and 38.7% for SRS alone (P = .5233); 1-year local control was 89% for SRS + WBRT and 71% for SRS alone (P < .001). Mean crude distant recurrence rate for SRS + WBRT was 36.6% and 54% for SRS alone (P < .001). Patients without WBRT were over 3 times more likely to require salvage therapy (P < .001). The addition of WBRT was associated with a decreased health-related quality of life assessment, mini mental status exam, and Hopkins Verbal Learning Test (P < .05). Five retrospective studies (n = 1122) were also included in a separate analysis and yielded findings that supported results from the randomized trials. Our systematic analysis demonstrates that adjuvant WBRT following SRS for the treatment of oligometastases in the brain is more effective at controlling local and distant recurrence than SRS alone, but there is no apparent benefit for survival or symptomology. The proven cognitive decline and neurotoxicity present with WBRT should be weighed against the benefit of local control. Prognosis of brain metastasis is poor regardless of current treatment and further exploration for alternative adjuvant treatment for SRS is warranted.

Dendritic cell vaccine for recurrent high-grade gliomas in pediatric and adult subjects: clinical trial protocol.

BACKGROUND Although there have been significant advances in understanding the basic pathogenesis of glioblastoma multiforme, the median survival of patients has changed little in the past 25 years. Recent studies have suggested that immune modulation through dendritic cell (DC) vaccines may stimulate the immune system against tumor antigens and potentially increase survival. OBJECTIVE To determine whether the use of adjuvant vaccination with autologous DCs (matured in situ after being loaded with tumor cell lysate derived from autologous refractory gliomas) is safe, feasible, and beneficial for adult and pediatric patients with recurrent high-grade gliomas. METHODS The study design is a single-center, nonrandomized, open phase I clinical trial. A total of 20 patients with malignant gliomas will be enrolled preoperatively over 2 years. Patients will be given adjuvant vaccination with autologous DCs loaded with tumor lysate after maximal safe surgical resection. EXPECTED OUTCOMES Using topical imiquimod before vaccination, it is anticipated that the immune response in vaccinated patients and potentially Overall survival will be greater than that demonstrated in the literature. We anticipate that there will be minimal side effects (minor dermatitis) associated with this treatment. DISCUSSION In the current trial, we assess immune response, safety, and survival using a novel vaccine protocol developed in Belgium that seems to markedly increase survival of certain subjects. Nevertheless, larger randomized clinical studies need to be performed to evaluate fully the efficacy of this therapy for both recurrent and newly diagnosed glioblastoma.