ZEB1 loss increases glioma stem cell tumorigenicity and resistance to chemoradiation.

OBJECTIVE: Glioblastoma has been known to be resistant to chemotherapy and radiation, whereas the underlying mechanisms of resistance have not been fully elucidated. The authors studied the role of the transcription factor ZEB1 (zinc finger E-box-binding homeobox 1 protein), which is associated with epithelial-mesenchymal transition (EMT) and is central to the stemness of glioblastoma, to determine its role in therapeutic resistance to radiation and chemotherapy. The authors previously demonstrated that ZEB1 is deleted in a majority of glioblastomas. METHODS: The authors explored resistance to therapy in the context of ZEB1 loss and overexpression in glioma stem cells (GSCs) and in patient data. RESULTS: Patients with ZEB1 loss had a shorter survival time than patients with wild-type ZEB1 in both the high- and low-MGMT groups. Consistent with the clinical data, mice implanted with ZEB1 knockdown GSCs showed shortened survival compared with mice inoculated with nonsilencing control (NS) short-hairpin RNA (shRNA) GSC glioblastoma. ZEB1-deleted GSCs demonstrated increased tumorigenicity with regard to proliferation and invasion. Importantly, GSCs that lose ZEB1 expression develop enhanced resistance to chemotherapy, radiotherapy, and combined chemoradiation. ZEB1 loss may lead to increased HER3 expression through the HER3/Akt pathway associated with this chemoresistance. Conversely, overexpression of ZEB1 in GSCs that are ZEB1 null leads to increased sensitivity to chemoradiation. CONCLUSIONS: The study results indicate that ZEB1 loss in cancer stem cells confers resistance to chemoradiation and uncovers a potentially targetable cell surface receptor in these resistant cells.

A Phase I Study of Autologous Dendritic Cell Vaccine Pulsed with Allogeneic Stem-like Cell Line Lysate in Patients with Newly Diagnosed or Recurrent Glioblastoma.

PURPOSE: Glioblastoma (GBM) is a heterogeneous malignancy with multiple subpopulations of cancer cells present within any tumor. We present the results of a phase I clinical trial using an autologous dendritic cell (DC) vaccine pulsed with lysate derived from a GBM stem-like cell line. PATIENTS AND METHODS: Patients with newly diagnosed and recurrent GBM were enrolled as separate cohorts. Eligibility criteria included a qualifying surgical resection or minimal tumor size, ≤ 4-mg dexamethasone daily dose, and Karnofsky score ≥70. Vaccine treatment consisted of two phases: an induction phase with vaccine given weekly for 4 weeks, and a maintenance phase with vaccines administered every 8 weeks until depletion of supply or disease progression. Patients with newly diagnosed GBM also received standard-of-care radiation and temozolomide. The primary objective for this open-label, single-institution trial was to assess the safety and tolerability of the autologous DC vaccine. RESULTS: For the 11 patients with newly diagnosed GBM, median progression-free survival (PFS) was 8.75 months, and median overall survival was 20.36 months. For the 25 patients with recurrent GBM, median PFS was 3.23 months, 6-month PFS was 24%, and median survival was 11.97 months. A subset of patients developed a cytotoxic T-cell response as determined by an IFNγ ELISpot assay. CONCLUSIONS: In this trial, treatment of newly diagnosed and recurrent GBM with autologous DC vaccine pulsed with lysate derived from an allogeneic stem-like cell line was safe and well tolerated. Clinical outcomes add to the body of evidence suggesting that immunotherapy plays a role in the treatment of GBM.

A phase I trial of surgical resection with Gliadel Wafer placement followed by vaccination with dendritic cells pulsed with tumor lysate for patients with malignant glioma.

High grade gliomas are associated with poor prognosis and high mortality. Conventional treatments and management of high grade gliomas have shown little improvement in 5-year overall survival. This phase I trial evaluated the safety, immunogenicity, and potential synergy of surgical resection with Gliadel Wafer implantation, followed by autologous tumor lysate-pulsed dendritic cell (DC) vaccine in patients with malignant glioma. Primary end points of this study were safety and surrogate markers of immunogenicity, overall survival, and progression free survival. Following surgical resection, Gliadel Wafers were placed along the resection cavity. Patients subsequently received intradermal injections of autologous tumor lysate-pulsed DC vaccines 3 times at 2 week intervals. Treatment response was evaluated clinically and through MRI at regular intervals. Twenty-eight patients received Gliadel Wafers and DC vaccination: 11 newly diagnosed (8 glioblastoma [GBM], 2 anaplastic astrocytoma [AA], and 1 anaplastic oligodendroglioma [AO]) and 17 recurrent (15 GBMs, 1 AA, and 1 AO) high grade gliomas. Immunogenicity data was collected for 20 of the 28 patients. Five of 20 patients showed elevated IFN-γ responses following vaccination. Median progression-free survival and overall survival for all GBM patients in the trial from the start of vaccination were 3.6 months and 16.9 months respectively. Comparisons between vaccine responders and non-vaccine responders were not statistically significant. Adjuvant autologous dendritic cells pulsed with tumor-lysate following resection and Gliadel Wafer placement is safe, elicits modest immunogenicity and shows similar clinical outcomes in patients who had DC vaccination in previous studies.

Blockade of a Laminin-411-Notch Axis with CRISPR/Cas9 or a Nanobioconjugate Inhibits Glioblastoma Growth through Tumor-Microenvironment Cross-talk.

There is an unmet need for the treatment of glioblastoma multiforme (GBM). The extracellular matrix, including laminins, in the tumor microenvironment is important for tumor invasion and progression. In a panel of 226 patient brain glioma samples, we found a clinical correlation between the expression of tumor vascular laminin-411 (α4ß1γ1) with higher tumor grade and with expression of cancer stem cell (CSC) markers, including Notch pathway members, CD133, Nestin, and c-Myc. Laminin-411 overexpression also correlated with higher recurrence rate and shorter survival of GBM patients. We also showed that depletion of laminin-411 α4 and ß1 chains with CRISPR/Cas9 in human GBM cells led to reduced growth of resultant intracranial tumors in mice and significantly increased survival of host animals compared with mice with untreated cells. Inhibition of laminin-411 suppressed Notch pathway in normal and malignant human brain cell types. A nanobioconjugate potentially suitable for clinical use and capable of crossing blood-brain barrier was designed to block laminin-411 expression. Nanobioconjugate treatment of mice carrying intracranial GBM significantly increased animal survival and inhibited multiple CSC markers, including the Notch axis. This study describes an efficient strategy for GBM treatment via targeting a critical component of the tumor microenvironment largely independent of heterogeneous genetic mutations in glioblastoma.Significance: Laminin-411 expression in the glioma microenvironment correlates with Notch and other cancer stem cell markers and can be targeted by a novel, clinically translatable nanobioconjugate to inhibit glioma growth.

Adult Brainstem Glioblastoma Multiforme: Long-term Survivor.

Adult, malignant brainstem gliomas are rare entities that often cause treatment conundrums due to the difficulty of surgical resection and, therefore, the absence of pathological diagnosis. This leads to a reliance on radiological imaging for diagnosis, which can often be unreliable. These shortcomings have made the treatment of brainstem gliomas challenging with unpredictable outcomes. The mainstay of treatment consists of chemotherapy and radiation; however, recurrence is inevitable. Predicting outcomes has been the major difficulty in treating these patients as adult malignant brainstem gliomas Grade II have a median survival between five to seven years while Grades III and IV are between 10-17 months (with some studies showing significantly longer survival in Grade III). Here, we present the case of a patient with the pathologic diagnosis of a right brachium pontis glioblastoma who had a remarkable survival of 73 months, whereas the expected median survival for these patients is 10-17 months.

Retrospective analysis of the tolerability and activity of lacosamide in patients with brain tumors: clinical article.

OBJECT: The object of this study was to determine the tolerability and activity of lacosamide in patients with brain tumors. METHODS: The authors reviewed the medical records at 5 US academic medical centers with tertiary brain tumor programs, seeking all patients in whom a primary brain tumor had been diagnosed and who were taking lacosamide. RESULTS: The authors identified 70 patients with primary brain tumors and reviewed seizure frequency and toxicities. The majority of the patients had gliomas (96%). Fifty-five (78%) had partial seizures only, and 12 (17%) had generalized seizures. Most of the patients (74%) were started on lacosamide because of recurrent seizures. Forty-six patients (66%) reported a decrease in seizure frequency, and 21 patients (30%) reported stable seizures. Most of the patients (54 [77%]) placed on lacosamide did not report any toxicities. CONCLUSIONS: This retrospective analysis demonstrated that lacosamide was both well tolerated and active as an add-on antiepileptic drug (AED) in patients with brain tumors. Lacosamide's novel mechanism of action will allow for concurrent use with other AEDs, as documented by its activity across many different types of AEDs used in this patient population. Larger prospective studies are warranted.

Phase I trial of a multi-epitope-pulsed dendritic cell vaccine for patients with newly diagnosed glioblastoma.

BACKGROUND: This study evaluated the safety and immune responses to an autologous dendritic cell vaccine pulsed with class I peptides from tumor-associated antigens (TAA) expressed on gliomas and overexpressed in their cancer stem cell population (ICT-107). METHODS: TAA epitopes included HER2, TRP-2, gp100, MAGE-1, IL13Rα2, and AIM-2. HLA-A1- and/or HLA-A2-positive patients with glioblastoma (GBM) were eligible. Mononuclear cells from leukapheresis were differentiated into dendritic cells, pulsed with TAA peptides, and administered intradermally three times at two-week intervals. RESULTS: Twenty-one patients were enrolled with 17 newly diagnosed (ND-GBM) and three recurrent GBM patients and one brainstem glioma. Immune response data on 15 newly diagnosed patients showed 33 % responders. TAA expression by qRT-PCR from fresh-frozen tumor samples showed all patient tumors expressed at least three TAA, with 75 % expressing all six. Correlations of increased PFS and OS with quantitative expression of MAGE1 and AIM-2 were observed, and a trend for longer survival was observed with gp100 and HER2 antigens. Target antigens gp100, HER1, and IL13Rα2 were downregulated in recurrent tumors from 4 HLA-A2+ patients. A decrease in or absence of CD133 expression was seen in five patients who underwent a second resection. At a median follow-up of 40.1 months, six of 16 ND-GBM patients showed no evidence of tumor recurrence. Median PFS in newly diagnosed patients was 16.9 months, and median OS was 38.4 months. CONCLUSIONS: Expression of four ICT-107 targeted antigens in the pre-vaccine tumors correlated with prolonged overall survival and PFS in ND-GBM patients. The goal of targeting tumor antigens highly expressed on glioblastoma cancer stem cells is supported by the observation of decreased or absent CD133 expression in the recurrent areas of gadolinium-enhanced tumors.

Atypical and anaplastic meningiomas treated with bevacizumab.

Atypical and anaplastic (WHO Grades II and III) meningiomas are aggressive tumors, and patients often progress despite surgery and radiation. There is no known effective chemotherapeutic option for these patients. Meningiomas have a high expression of vascular endothelial growth factor receptor (VEGFR). We sought to retrospectively study the activity of bevacizumab, which is an anti-angiogenic agent targeting the VEGF pathway in these tumors. This is a retrospective review of WHO Grade II and III meningiomas treated at four institutions, selecting only those patients who received bevacizumab. We analyzed radiographic response according to standard RANO criteria, progression-free survival (PFS) and overall survival from the initiation of bevacizumab therapy using Kaplan-Meier statistics. We identified 15 patients across four institutions who carried a diagnosis of atypical or anaplastic meningioma and were treated with bevacizumab. Best radiographic response was stable disease. MR perfusion studies showed decreased tumor blood volume in one patient. Three patients developed non-fatal intratumoral hemorrhage. Median PFS was 26 weeks (95 % CI, 10-29 weeks). Six month PFS rate was 43.8 % (95 % CI, 15.7-69.1 %). Bevacizumab was well-tolerated in our patients, and may be considered in patients who have exhausted radiation and surgical options. Prospective studies are required to define the safety and efficacy of bevacizumab in atypical and anaplastic meningiomas.