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In JoVE (1)
Other Publications (34)
- Cancer Journal (Sudbury, Mass.)
- Molecular and Cellular Neurosciences
- Neurosurgery
- Surgical Neurology
- Current Stem Cell Research & Therapy
- Neurosurgery
- Neurosurgery
- Neurosurgical Focus
- Expert Review of Neurotherapeutics
- Neurosurgery
- Neurosurgery
- Neurosurgery
- Journal of Experimental Therapeutics & Oncology
- Journal of Experimental Therapeutics & Oncology
- Neurosurgery
- Journal of Neurosurgery
- Journal of Cancer Research and Therapeutics
- Neurosurgery
- Journal of Neurosurgery. Spine
- Brachytherapy
- Journal of Neuro-oncology
- Neurosurgery
- Journal of Experimental Therapeutics & Oncology
- Journal of Neuro-oncology
- Journal of Neurosurgery
- Journal of Neuro-oncology
- Neurosurgical Focus
- Neurosurgery
- Cancers
- Neurosurgery
- Journal of Experimental Therapeutics & Oncology
- Journal of Neuro-oncology
- Neurosurgery
- PloS One
Articles by John A. Boockvar in JoVE
JoVE General
Assessing Neural Stem Cell Motility Using an Agarose Gel-based Microfluidic Device
1Biomedical Engineering Department, Cornell University, 2Neurosurgical Laboratory for Translational Stem Cell Research, Weill Cornell Brain Tumor Center, Weill Cornell Medical College of Cornell University, 3Cell Morphology Department, Instituto de Investigacion Principe Felipe, 4Department of Chemical and Biomolecular Engineering, Cornell University
We demonstrate that the over expression of epidermal growth factor receptors (EGFR) enhances the motility of neural stem cells(NSCs) using a novel agarose gel based microfluidic device. This technology can be readily adaptable to other mammalian cell systems where cell sources are scarce, such as human neural stem cells, and the turn around time is critical.
Other articles by John A. Boockvar on PubMed
Neural Stem Cell Biology May Be Well Suited for Improving Brain Tumor Therapies
Neural stem cells (NSCs) are capable of tremendous migratory potential to areas of pathology in the central nervous system. When implanted into a diseased or injured nervous system, NSCs can travel through great distances to and engraft within areas of discrete as well as diffuse abnormalities. Engraftment is often followed by integration into the local neural milieu, accompanied by stable gene expression from the NSCs. In addition, the pluripotency of NSCs endows them with the capability to replace diseased tissues in an appropriate manner. Recent evidence has also suggested that engrafted exogenous NSCs may have effects on the surrounding microenvironment, such as promoting protection and/or regeneration of host neural pathways. These characteristics of NSCs would seem to make them ideal agents for the treatment of various central nervous system pathologies, especially brain tumors. Brain tumors are generally difficult to treat because of the unique location of the lesions. In primary gliomas, the extensive infiltrative nature of the tumor cells presents a challenge for their effective and total eradication, hence the high rate of treatment failure and disease recurrence. In addition, normal brain structures are distorted and are often destroyed by the growing neoplasm. Even with effective therapy to surgically resect and destroy the neoplastic tissues, the brain is still injured, which often leaves the patient in a debilitated state. The unique ability of NSCs to "home in" on tumor cells followed by the delivery of a desired gene product makes the NSC a very promising agent in brain tumor therapy. Cytolytic viruses and genes coding for anti-tumor cytokines, pro-drug converting enzymes, and various neurotrophic factors have all been engineered into engraftable NSCs for delivery to tumors. When they are specially tagged, such injected NSCs can be visualized with the use of novel imaging techniques and tracked in vivo within living animals over real time. If the NSCs were also capable of participating in the subsequent repair and regeneration of the tumor-afflicted brain-at present a potential but as-yet-unproven aspect of this intervention-then its role in abetting anti-tumor therapy would be complete. It is important to emphasize, however, that the use of NSCs is adjunctive and is not a replacement for other therapies that should be used in parallel.
Constitutive EGFR Signaling Confers a Motile Phenotype to Neural Stem Cells
The epidermal growth factor receptor (EGFR) has been shown to play an important role in brain development, including stem and precursor cell survival, proliferation, differentiation, and migration. To further examine the temporal and spatial requirements of erbB signals in uncommitted neural stem cells (NSCs), we expressed the ligand-independent EGF receptor, EGFRvIII, in C17.2 NSCs. These NSCs are known to migrate and to evince a tropic response to neurodegenerative environments in vivo but for which an underlying mechanism remains unclear. We show that enhanced erbB signaling via constitutive kinase activity of EGFRvIII in NSCs sustains an immature phenotype and enhances NSC migration.
Experimental Traumatic Brain Injury Modulates the Survival, Migration, and Terminal Phenotype of Transplanted Epidermal Growth Factor Receptor-activated Neural Stem Cells
We have previously shown that constitutively active epidermal growth factor receptor signaling enhances the survival and motility of engrafted neural stem cells (NSCs) when transplanted into normal adult brain. In the present study, using the C17.2 NSC line stably transfected with the constitutively active epidermal growth factor receptor vIII, we sought to evaluate the phenotype of NSCs after engraftment into the milieu of traumatic head injury.
Dural Cavernous Angioma of the Posterior Sagittal Sinus: Case Report
Extraaxial cavernous hemangiomas (cavernomas) are very rare lesions, and less than 20 descriptions of these lesions outside the middle fossa have been reported. In this report, we describe a dural cavernous angioma involving the posterior sagittal sinus and discuss the clinical, radiological, operative, and histological features of this very uncommon lesion.
The Duality of Epidermal Growth Factor Receptor (EGFR) Signaling and Neural Stem Cell Phenotype: Cell Enhancer or Cell Transformer?
Recruitment of neural stem cells (NSCs) represents an elegant strategy for replacing adult central nervous system (CNS) cells lost to injury or disease. However, except in the rostral migratory stream to the olfactory bulb, the adult CNS harbors a relatively non permissive environment for motility of neural stem cells. This opens the possibility of therapeutic enhancement of NSC motility towards sites of CNS injury or disease. The Epidermal Growth Factor Receptor (EGFR) is involved in the activation of a number of downstream pathways that regulate the phenotype of progenitor cells. Activated EGFR tyrosine kinase activity enhances NSC migration, proliferation, and survival. However, EGFR signaling is also known to play a role in the most malignant and highly invasive of human tumors, glioblastoma multiforme (GBM). Recent evidence supports the theory that GBM derives from a 'cancer stem cell' and that EGFR signals are commonly altered in these precursor cells. This article will review the role of EGFR signaling as it relates to neural stem cell motility and invasion. The duality of altered EGFR signaling in neural progenitor cells is discussed and opportunities for enhancing the recruitment of adult progenitors, and consequences of altering EGFR signaling in progenitor cells will be highlighted.
Use of Human Neural Tissue for the Generation of Progenitors
Accumulating evidence suggests that a better understanding of normal human brain stem cells and tumor stem cells (TSCs) will have profound implications for treating central nervous system disease during the next decade. Neurosurgeons routinely resect excess surgical tissue containing either normal brain stem cells or TSCs. These cells are immediately available for expansion and use in basic biological assays, animal implantation, and comparative analysis studies. Although normal stem cells have much slower kinetics of expansion than TSCs, they are easily expandable and can be frozen for future use in stem cell banks. This nearly limitless resource holds promise for understanding the basic biology of normal brain stem cells and TSCs, which will likely direct the next major shift in therapeutics for brain tumors, brain and spinal cord injury, and neurodegenerative disease. This report reviews the progress that has been made in harvesting and expanding both normal and tumor-derived stem cells and emphasizes the integral role neurosurgeons will play in moving the neural stem cell field forward.
Long-term Expansion of Adult Human Brain Subventricular Zone Precursors
Many common neurosurgical procedures, including anterior temporal lobectomy and endoscopic ventricular puncture, allow neurosurgeons to retrieve portions of the germinal subventricular zone (SVZ). Isolation and maintenance of precursor cells from this zone can be used for hypothesis-driven experiments with a goal of improving our understanding of the basic mechanisms of central nervous system injury or disease and the potential of cell-based therapies to treat them. This article details our ability to reliably harvest, isolate, characterize, and maintain normal adult human brain SVZ precursor cells.
New Strategy for the Analysis of Phenotypic Marker Antigens in Brain Tumor-derived Neurospheres in Mice and Humans
Brain tumor stem cells (TSCs) hypothetically drive the malignant phenotype of glioblastoma multiforme (GBM), and evidence suggests that a better understanding of these TSCs will have profound implications for treating gliomas. When grown in vitro, putative TSCs grow as a solid sphere, making their subsequent characterization, particularly the cells within the center of the sphere, difficult. Therefore, the purpose of this study was to develop a new method to better understand the proteomic profile of the entire population of cells within a sphere.
Interstitial Infusion of Erlotinib in the Rodent Brain
A critical need exists for the development of novel forms of treatment for high-grade glioma. Molecular characterization of high-grade glioma has shown overexpression of the epidermal growth factor receptor, antagonists to which, including erlotinib, may prevent tumor growth. Interstitial infusion is a mode of local delivery which bypasses the blood-brain barrier and utilizes a pressure-dependent gradient to enhance drug uniformity and volume of distribution. Interstitial infusion of erlotinib was performed to the striatum of 12 rats in increasing, therapeutic doses. No evidence of clinical or histopathologic toxicity was found. In this experimental study we demonstrate that interstitial infusion of erlotinib is safe in the rodent brain, and may have potential applicability for the treatment of high-grade glioma.
Superselective Intraarterial Cerebral Infusion of Bevacizumab: a Revival of Interventional Neuro-oncology for Malignant Glioma
Glioblastoma Multiforme (GBM) is a uniformly fatal disease with a median survival of approximately 15 months. Recent monoclonal antibody therapies such as Bevacizumab (Avastin) have been shown to be active in GBM and to prolong survival in patients with recurrent malignant glioma. Therefore, patients routinely receive intravenous (i.v.) Bevacizumab (10 mg/kg) every two weeks when they have recurred following standard therapy with chemoradiation. I.v Bevacizumab; however, can cause significant systemic side effects including bowel perforation and pulmonary embolism. In addition, the blood brain barrier (BBB) continues to provide an obstacle to the effective delivery of the antibody to the brain tumor bed. In order to overcome the BBB, and to limit the systemic toxicity of i.v. Bevacizumab, we have begun a Phase I clinical trial to test the safety of transient blood brain barrier disruption with intraarterial (IA) Mannitol followed by superselective intraarterial cerebral infusion (SIACI) of Bevacizumab. This case report describes the technical aspects of this procedure and its associated benefits and risks. This novel delivery method, which may herald the revival of Interventional Neuro-oncology, may significantly alter the way therapy is administered to patients with GBM.
High-viscosity Polymethylmethacrylate Cement for Endoscopic Anterior Cranial Base Reconstruction
Endoscopic endonasal transsphenoidal surgery (ETSS) is an effective, minimally invasive approach for the resection of anterior skull base tumors. Cerebrospinal leakage is a common complication, and repair of the anterior skull base defect with alloplastic materials has been used to minimize the risk of postoperative CSF rhinorrhea and meningitis. Injectable cements, such as low-viscosity polymethylmethacrylate (PMMA), are useful for cranial base reconstruction because they are easy to shape to the contour of the defect. These low-viscosity materials, however, are more susceptible to leakage into the nasal cavity prohibiting their use and are prone to cracking upon hardening. Cement extravasation not only obstructs the operator's view during placement, but it is also associated with significant local and systemic complications. High-viscosity (HV) PMMA-based cement and its specialized delivery system have recently been shown to be safe and effective in human applications. Moreover, its constant high viscosity significantly reduces cement leakage and its associated complications. The authors hypothesized that this type of cement would therefore be ideal for ETSS to repair anterior skull base defects. The authors report their experience using HV-PMMA to reconstruct the anterior skull base in 12 patients following ETSS. The unique puttylike consistency of this material is easy to work, malleable, does not leak into the nasal cavity, does not aspirate into suction tubing, and hardens without cracks in less than 10 minutes. None of the 12 patients suffered postoperative CSF leaks or infections more than 8 months, on average, after surgery. Although not necessary in all cases of ETSS, the authors conclude that HV-PMMA, if needed, may be an excellent choice for reconstructing the anterior skull base after ETSS. Further studies are needed to better assess the long-term outcomes of HV-PMMA cement and its use in repairing skull base defects after extended ETSS.
Feasibility and Safety of GliaSite Brachytherapy in Treatment of CNS Tumors Following Neurosurgical Resection
To investigate feasibility and safety of GliaSite brachytherapy for treatment of central nervous system (CNS) tumors following neurosurgical resection. We report mature results of long-term follow-up, outcomes and toxicity.
Results and Risk Factors for Recurrence Following Single-level Tubular Lumbar Microdiscectomy
The use of minimally invasive surgical techniques, including microscope-assisted tubular lumbar microdiscectomy (tLMD), has gained increasing popularity in treating lumbar disc herniations (LDHs). This particular procedure has been shown to be both cost-efficient and effective, resulting in outcomes comparable to those of open surgical procedures. Lumbar disc herniation recurrence necessitating reoperation, however, remains an issue following spinal surgery, with an overall reported incidence of approximately 3-13%. The authors' aim in the present study was to report their experience using tLMD for single-level LDH, hoping to provide further insight into the rate of surgical recurrence and to identify potential risk factors leading to this complication.
The Role of Dose Escalation with Intracavitary Brachytherapy in the Treatment of Localized CNS Malignancies: Outcomes and Toxicities of a Prospective Study
This single-institution prospective study was designed to investigate the feasibility and safety of dose escalation with GliaSite (Proxima Therapeutics Inc., Alpharetta, GA) brachytherapy for the treatment of patients with newly diagnosed and recurrent central nervous system (CNS) tumors after neurosurgical resection. We now report mature results of this trial, its outcomes, and a toxicity profile.
Activated EGFR Signaling Increases Proliferation, Survival, and Migration and Blocks Neuronal Differentiation in Post-natal Neural Stem Cells
Recent evidence supports the notion that transformation of undifferentiated neural stem cell (NSC) precursors may contribute to the development of glioblastoma multiforme (GBM). The over-expression and mutation of the epidermal growth factor receptor (EGFR), along with other cellular pathway mutations, plays a significant role in GBM maintenance progression. Though EGFR signaling is important in determining neural cell fate and conferring astrocyte differentiation, there is a limited understanding of its role in NSC and tumor stem cell (TSC) biology. We hypothesized that EGFR expression and mutation in post-natal NSCs may contribute to cellular aggressiveness including enhanced cellular proliferation, survival and migration. Stable subclones of C17.2 murine NSCs were transfected to over-express either the wild-type EGFR (wtEGFR) or its most common mutated variant EGFRvIII. Activated EGFR signaling in these cells induced behaviors characteristic of GBM TSCs, including enhanced proliferation, survival and migration, even in the absence of EGF ligand. wtEGFR activation was also found to block neuronal differentiation and was associated with a dramatic increase in chemotaxis in the presence of EGF. EGFRvIII expression lead to an increase in NSC proliferation and survival, while it simultaneously blocked neuronal differentiation and promoted glial fate. Our findings suggest that activated EGFR signaling enhances the aggressiveness of NSCs. Understanding the regulatory mechanisms of NSCs may lend insight into deregulated mechanisms of GBM TSC invasion, proliferation, survival and resistance to current treatment modalities.
EGFR Signaling is Differentially Activated in Patient-derived Glioblastoma Stem Cells
Evidence suggests that stem-like cells are responsible for initiation, maintenance and recurrence of solid tumors, including Glioblastoma Multiforme (GBM). GBM is an intractable, highly lethal tumor of the central nervous system. Although epidermal growth factor receptor (EGFR) is highly expressed in many GBMs, anti-EGFR therapies have been unsuccessful as treatment. Few studies have examined EGFR activation in GBM stem cells (GSCs) to determine if patient-specific GSCs are amenable to anti-EGFR therapy pre-clinically. We hypothesized that EGFR activation in GSCs varied between patients and was an important determinant of responsiveness to anti-EGFR therapy. Cell cycle and apoptosis analysis was performed on tumor-spheres by immuncytochemistry in the presence and absence of the AG1478. Second messenger pathways operative in these processes were elucidated by immunoblotting. EGFR activated AKT and inactivated GSK3beta in EGFR+/PTEN+ GSCs. AG1478 and erlotinib significantly decreased the total number of tumor-spheres that EGFR+/ PTEN+ GSCs generated and the rate of sphere formation. Inhibition of EGFR signaling by AG1478 increased GSC senescence and apoptosis, likely via inhibition of AKT and activation of GSK3beta. Sphere formation by EGFR-/ PTEN- GSCs was independent of EGF stimulation, but dependant on B27 growth supplement. Our data suggest that EGFR+/PTEN+ GSCs are susceptible to anti-EGFR therapy in vitro.
Understanding the Role of Tumor Stem Cells in Glioblastoma Multiforme: a Review Article
It has been hypothesized that cancer stem cells (CSC) may account for the pathogenesis underlying various tumors, including GBM. Markers of these CSCs can be potentially used as therapeutic targets. In this review, we discuss the most recent information regarding CSCs, their molecular biology and their potential role in GBM.
Safety and Maximum Tolerated Dose of Superselective Intraarterial Cerebral Infusion of Bevacizumab After Osmotic Blood-brain Barrier Disruption for Recurrent Malignant Glioma. Clinical Article
The authors assessed the safety and maximum tolerated dose of superselective intraarterial cerebral infusion (SIACI) of bevacizumab after osmotic disruption of the blood-brain barrier (BBB) with mannitol in patients with recurrent malignant glioma.
Optimization of Glioblastoma Multiforme Stem Cell Isolation, Transfection, and Transduction
It has been postulated that brain tumor stem cells (TSCs) may be the population of cells responsible for the maintenance and recurrence of glioblastoma multiforme (GBM). The purpose of this study was to optimize a reproducible protocol for generating TSCs for their subsequent transfection or transduction. Patient GBMs were enzymatically and mechanically dissociated and tumor spheres were resuspended in appropriate media and analyzed to ensure they met stem cell criteria. These cells were then transfected with a plasmid or transduced with a viral vector to introduce a previously absent gene and then allowed to form tumor spheres. Tumor spheres were generated from patient GBMs without contamination. These cells met stringent criteria as stem cells, including multipotentiality and self-renewal. High efficiency transfection and transduction of tumor spheres was possible, even at the core of the sphere. This allowed for the introduction of new genes to the TSCs, as evidenced by fluorescent microscopy and Western blot analysis. This study is a guide to optimize the generation of patient derived GBM tumor spheres without RBC and dead cell contamination. GBM TSCs within tumor spheres can easily be transfected with plasmids or transduced with a virus. This is important from a therapeutic perspective if gene replacement is to be successful in replacing genes lost in GBM progression or to knock down or silence genes that are over-expressed in malignant brain tumors.
Endoscopic Endonasal Transsphenoidal Surgery for Functional Pituitary Adenomas
The purpose of this study was to analyze preoperative predictors of endocrinological remission following endonasal endoscopic resection of therapy-resistant prolactin-, growth hormone (GH)-, and adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas and to establish benchmarks for cure by using the most recent consensus criteria.
Neural Stem Cells and Glioma Stem-like Cells Respond Differently to Chemotherapeutic Drugs: Selectivity at the Cellular Level
Glioblastoma Stem-Like Cells-Biology and Therapeutic Implications
The cancer stem-cell hypothesis proposes that malignant tumors are likely to encompass a cellular hierarchy that parallels normal tissue and may be responsible for the maintenance and recurrence of glioblastoma multiforme (GBM) in patients. The purpose of this manuscript is to review methods for optimizing the derivation and culturing of stem-like cells also known as tumor stem cells (TSCs) from patient-derived GBM tissue samples. The hallmarks of TSCs are that they must be able to self-renew and retain tumorigenicity. The isolation, optimization and derivation of TSCs as outlined in this review, will be important in understanding biology and therapeutic applications related to these cells.
Cost Analysis of Intra-arterial Versus Intra-venous Delivery of Bevacizumab for the Treatment of Recurrent Glioblastoma Multiforme
Intra-arterial bevacizumab (IA BV) has been recently identified to be safe in the treatment of recurrent GBM. In this study, we sought to perform a cost analysis of IA BV versus IV BV especially also taking account of patient progression free survival (PFS) and overall survival (OS). We show that IA BV is significantly more cost effective than conventional IV therapy.
Pineal Parenchymal Tumor of Intermediate Differentiation with Papillary Features: a Continuum of Primary Pineal Tumors?
Pineal parenchymal tumors comprise a rare group of primary neoplasms of the pineal gland. We describe a case involving a 29-year-old woman who presented with signs and symptoms of hydrocephalus secondary to a pineal region tumor obstructing the third ventricle. Surgical resection was performed and pathological analysis revealed a novel diagnosis consistent with a pineal parenchymal tumor of intermediate differentiation (PPTID) with transition to a papillary tumor of the pineal region (PTPR). To our knowledge, this particular pineal region tumor pathology has not yet been reported in the literature and highlights the continuum with which primary pineal tumors exist. We provide a review of the existing literature on pineal region tumors, specifically PTPR and PPTID, and offer insight into the management of these rare neoplasms.
The Contribution of Notch Signaling to Glioblastoma Via Activation of Cancer Stem Cell Self-renewal: The Role of the Endothelial Network
Protein Phosphatase 2A Mediates Dormancy of Glioblastoma Multiforme-Derived Tumor Stem-Like Cells During Hypoxia
The hypoxic microenvironment of glioblastoma multiforme (GBM) is thought to increase resistance to cancer therapies. Recent evidence suggests that hypoxia induces protein phosphatase 2A (PP2A), a regulator of cell cycle and cell death. The effects of PP2A on GBM tumor cell proliferation and survival during hypoxic conditions have not been studied.
