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ABSTRACT: CD147 (alias emmprin or basigin), an integral plasma membrane glycoprotein and a member of the Ig superfamily, is widespread in normal tissues, but highly up-regulated in many types of malignant cancer cells. CD147 is multifunctional, with numerous binding partners. Recent studies suggest that complexes of CD147 with the hyaluronan receptor CD44 and associated transporters and receptor tyrosine kinases are enriched in the plasma membrane of cancer stem-like cells. Here, we show that subpopulations of tumor cell lines constitutively expressing high levels of cell-surface CD147 exhibit cancer stem-like cell properties; that is, they exhibit much greater invasiveness, anchorage-independent growth, spheroid formation, and drug resistance in vitro and higher tumorigenicity in vivo than those constitutively expressing low levels of cell-surface CD147. Primary CD147-rich cell subpopulations derived from mouse mammary adenocarcinomas also exhibit high levels of invasiveness and spheroid-forming capacity, whereas CD147-low cells do not. Moreover, localization at the plasma membrane of CD44, the EGF receptor, the ABCB1 and ABCG2 drug transporters, and the MCT4 monocarboxylate transporter is elevated in cells constitutively expressing high levels of cell-surface CD147. These results show that CD147 is associated with assembly of numerous pro-oncogenic proteins in the plasma membrane and may play a fundamental role in properties characteristic of cancer stem-like cells.
American Journal Of Pathology 11/2012; · 4.89 Impact Factor
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Bernard L Maria
Journal of child neurology 09/2011; 26(9):1072-3. · 1.59 Impact Factor
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Journal of child neurology 09/2011; 26(9):1074-100. · 1.59 Impact Factor
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Bernard L Maria
Journal of child neurology 09/2010; 25(9):1079. · 1.59 Impact Factor
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Journal of child neurology 09/2010; 25(9):1080-97. · 1.59 Impact Factor
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Elizabeth B Claus,
May Abdel-Wahab,
Peter C Burger,
Herbert H Engelhard,
David W Ellison,
Nicholas Gaiano,
David H Gutmann,
Daniel A Heck,
Eric C Holland,
George I Jallo,
Carol Kruchko,
Larry E Kun, Bernard L Maria,
Zoran Rumboldt,
Daniela Seminara,
Giovanna M Spinella,
Linda Stophel,
Robert Wechsler-Reya,
Margaret Wrensch,
Richard J Gilbertson
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ABSTRACT: The relative rarity of spinal cord tumors has hampered the study of these uncommon nervous system malignancies. Consequently, the understanding of the fundamental biology and optimal treatment of spinal cord tumors is limited, and these cancers continue to inflict considerable morbidity and mortality in children and adults. As a first step to improving the outcome of patients affected with spinal cord tumors, the National Institutes of Health Office of Rare Diseases Research in cooperation with the National Cancer Institute and the National Institute of Neurological Disorders and Stroke convened a workshop to discuss the current status of research and clinical management of these tumors. The overall goal of this meeting was to initiate a process that would eventually translate fundamental basic science research into improved clinical care for this group of patients. Investigational priorities for each of these areas were established, and the opportunities for future multidisciplinary research collaborations were identified.
Journal of neurosurgery. Spine 02/2010; 12(2):117-21. · 1.61 Impact Factor
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ABSTRACT: Cerebral palsy will affect nearly 10% of the 60,000 very low-birth-weight infants born in the United States in the next year, and an even greater percentage will display some form of permanent neurological impairment resulting from injury to the preterm brain. The 2008 Neurobiology of Disease in Children Symposium, held in conjunction with the 37th annual meeting of the Child Neurology Society, aimed to define current knowledge and to develop specific aims for future clinical, translational, and fundamental science. A complex interplay of both destructive and developmental forces is responsible for injury to the preterm brain. Advances in imaging and histology have implicated a variety of cell types, though preoligodendrocyte injury remains the focus. Research into different mechanisms of injury is facilitating new neuroprotective and rehabilitative interventions. A cooperative effort is necessary to translate basic research findings into clinically effective therapies and better care for these children.
Journal of child neurology 10/2009; 24(9):1064-84. · 1.59 Impact Factor
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ABSTRACT: Malignant peripheral nerve sheath tumors (MPNST) develop in approximately 10% of neurofibromatosis type-1 patients and are a major contributing factor to neurofibromatosis-1 patient mortality and morbidity. MPNSTs are multidrug resistant, and thus long-term patient survival rates are poor after standard doxorubicin or multiagent chemotherapies. We show that the hyaluronan receptor CD44 forms complexes with multidrug transporters, BCRP (ABCG2) and P-glycoprotein (ABCB1), in the plasma membrane of human MPNST cells. Small hyaluronan oligosaccharides antagonize hyaluronan-CD44-mediated processes and inhibit hyaluronan production. Treatment of MPNST cells with the hyaluronan oligomers causes disassembly of CD44-transporter complexes and induces internalization of CD44, BCRP, and P-glycoprotein. Consequently, the oligomers suppress drug transporter activity and increase sensitivity to doxorubicin treatment in culture. In vivo, systemic administration of hyaluronan oligomers inhibits growth of MPNST xenografts. Moreover, the oligomers and doxorubicin act synergistically in vivo, in that combined suboptimal doses induce tumor regression to a greater extent than the additive effects of each agent alone. These findings indicate that constitutive hyaluronan-CD44 interactions contribute to drug transporter localization and function at the plasma membrane, and that attenuating hyaluronan-CD44 interactions sensitizes MPNSTs to doxorubicin in vitro and in vivo. These results also show the potential efficacy of hyaluronan oligomers, which are nontoxic and nonimmunogenic, as an adjuvant for chemotherapy in MPNST patients.
Cancer Research 07/2009; 69(12):4992-8. · 7.86 Impact Factor
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ABSTRACT: Spinal muscular atrophy (SMA) is characterized by degenerating lower motor neurons and an increased incidence of congenital bone fractures. Survival motor neuron (SMN) levels are significantly reduced due to deletions/mutations in the telomeric SMN1 gene in these patients. We utilized the Smn(-/-) SMN2 mouse model of SMA to determine the functional role for SMN in bone remodelling. microCT analysis of lumber vertebrae, tibia and femur bones from SMA mice revealed an osteoporotic bone phenotype. Histological analysis demonstrated a thin porous cortex of cortical bone and thin trabeculae at the proximal end of the growth plate in the vertebrae of SMA mice compared to wild-type mice. Histochemical staining of the vertebrae showed the presence of abundant activated osteoclasts on the sparse trabeculae and on the endosteal surface of the thin cortex in SMA mice. Histomorphometric analysis of vertebrae from SMA mice showed an increased number of osteoclasts. Serum TRAcP5b and urinary NTx levels were elevated, consistent with increased bone resorption in these mice. SMA mice showed a significant decrease in the levels of osteoblast differentiation markers, osteocalcin, osteopontin and osterix mRNA expression; however, there were no change in the levels of alkaline phosphatase expression compared to WT mice. SMA mouse bone marrow cultures revealed an increased rate of osteoclast formation (54%) and bone resorption capacity (46%) compared to WT mice. Pre-osteoclast cells from SMA mice showed constitutive up-regulation of RANK receptor signalling molecules critical for osteoclast differentiation. Our results implicate SMN function in bone remodelling and skeletal pathogenesis in SMA. Understanding basic mechanisms of SMN action in bone remodelling may uncover new therapeutic targets for preventing bone loss/fracture risk in SMA.
The Journal of Pathology 04/2009; 219(1):52-60. · 6.32 Impact Factor
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ABSTRACT: Interactions of hyaluronan with CD44 in tumor cells play important cooperative roles in various aspects of malignancy and drug resistance. Emmprin (CD147; basigin) is a cell surface glycoprotein of the immunoglobulin superfamily that is highly up-regulated in malignant cancer cells and stimulates hyaluronan production, as well as several downstream signaling pathways. Emmprin also interacts with various monocarboxylate transporters (MCT). Malignant cancer cells use the glycolytic pathway and require MCTs to efflux lactate that results from glycolysis. Glycolysis and lactate secretion contribute to malignant cell behaviors and drug resistance in tumor cells. In the present study, we find that perturbation of endogenous hyaluronan, using small hyaluronan oligosaccharides, rapidly inhibits lactate efflux from breast carcinoma cells; down-regulation of emmprin, using emmprin small interfering RNA, also results in decreased efflux. In addition, we find that CD44 coimmunoprecipitates with MCT1, MCT4, and emmprin and colocalizes with these proteins at the plasma membrane. Moreover, after treatment of the cells with hyaluronan oligosaccharides, CD44, MCT1, and MCT4 become localized intracellularly whereas emmprin remains at the cell membrane. Together, these data indicate that constitutive interactions among hyaluronan, CD44, and emmprin contribute to regulation of MCT localization and function in the plasma membrane of breast carcinoma cells.
Cancer Research 02/2009; 69(4):1293-301. · 7.86 Impact Factor
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ABSTRACT: Neurofibromatosis type 1 (NF1) is an autosomal dominant condition with a worldwide incidence of approximately 1 per 2500 to 3000 individuals. Caused by a germ-line-inactivating mutation in the NF1 gene on chromosome 17, the disease is associated with increased morbidity and mortality. In the past several years, significant progress has been made in standardizing management of the major clinical features of neurofibromatosis type 1. Moreover, improved understanding of how the neurofibromatosis type 1 protein, neurofibromin, regulates cell growth recently provided insight into the pathogenesis of the disease and has led to the development of new therapies. In this review, we describe the clinical manifestations, recent molecular and genetic findings, and current and developing therapies for managing clinical problems associated with neurofibromatosis type 1.
PEDIATRICS 02/2009; 123(1):124-33. · 4.47 Impact Factor
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Bernard L Maria,
Nalin Gupta,
Anne G Gilg,
May Abdel-Wahab,
Anthony P Leonard,
Mark Slomiany,
William G Wheeler,
Lauren B Tolliver,
Michael A Babcock,
John T Lucas,
Bryan P Toole
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ABSTRACT: Although significant advances have been made in treating malignant pediatric central nervous system tumors such as medulloblastoma, no effective therapy exists for diffuse pontine glioma or intramedullary spinal astrocytoma. Biology of these 2 tumors is poorly understood, in part because diffuse pontine gliomas are not treated surgically, and tumor specimens from intramedullary spinal astrocytomas are rare and minuscule. At the 2007 Neurobiology of Disease in Children Symposium, we presented evidence that malignant glioma behaviors, including antiapoptosis, invasiveness, and treatment resistance, are enhanced by hyaluronan, an extracellular glycosaminoglycan. We review the clinical course of pediatric intramedullary spinal astrocytoma and diffuse pontine glioma, and show expression of membrane proteins that interact with hyaluronan: CD44, extracellular matrix metalloproteinase inducer, and breast cancer resistance protein (BCRP/ABCG2). Furthermore, we describe novel animal models of these tumors for preclinical studies. These findings suggest that hyaluronan antagonism has potential therapeutic value in malignant central nervous system tumors.
Journal of child neurology 11/2008; 23(10):1214-20. · 1.59 Impact Factor
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ABSTRACT: Ceruloplasmin (glycosylphosphatidylinositol-linked ferroxidase associated with normal astrocytes) can also be secreted by glioma cells, where its function is unknown. Ceruloplasmin is not only present in glioma cells and in human glioma specimens but also is enriched in highly malignant glioma stem-like cells. Hyaluronan is a large extracellular glycosaminoglycan that enhances malignant glioma behaviors by interacting with CD44 receptors and by downstream activation of signaling proteins and transporters associated with malignancy. We examined the relationship between hyaluronan and ceruloplasmin expression in glioma stem-like cells. Antagonism of hyaluronan interactions with short-fragment hyaluronan oligomers decreased ceruloplasmin expression in parental and stem-like glioma cells in vivo and in cell culture, implying that hyaluronan regulates ceruloplasmin expression. Further gain and loss-of-function studies are needed to fully define the relationship between hyaluronan and ceruloplasmin, and ceruloplasmin's effect on malignant behaviors.
Journal of child neurology 11/2008; 23(10):1221-30. · 1.59 Impact Factor
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ABSTRACT: Central nervous system tumors are the most common solid tumors in children. Many histological subtypes and biological variants exist. The 2007 Neurobiology of Disease in Children Symposium, held in conjunction with the 36th annual meeting of the Child Neurology Society, aimed to define current knowledge in the field and to develop specific aims for future clinical, translational, and fundamental science. Because of advances in structural and metabolic imaging, surgical technique, and combination therapies, the life expectancy of children with some of the most common tumors, such as cerebellar astrocytomas and medulloblastomas, has improved. Other common tumor types, including diffuse pontine gliomas and malignant embryonal tumors, still have a dismal prognosis. As novel therapies are identified for pediatric central nervous system tumors, long-term survival may be associated with considerable disability. A cooperative effort is crucial to early diagnosis and to translating basic research findings into safe, effective new treatments.
Journal of child neurology 11/2008; 23(10):1103-21. · 1.59 Impact Factor
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ABSTRACT: Joubert syndrome (JS) is characterized by absence of decussation of both corticospinal tracts and superior cerebellar peduncles (SCP). Our hypothesis was that evidence for absence of SCP decussation may be found on routine brain MRI studies. Midsagittal T1-weighted images from 20 JS patients and 30 age-matched controls were retrospectively reviewed. An ill-defined area of lower T1 signal in the inferior midbrain was considered the sign of SCP decussation, and its presence or absence was noted. Fractional anisotropy (FA) maps were obtained in three JS patients and four controls. The SCP decussation was not visualized in any subject under 30 months of age. In subjects above 30 months of age the sign of the SCP decussation was absent in all 6 JS patients and present in all 16 controls. FA maps confirmed the absence of the SCP decussation in the JS patients. The SCP decussation is well seen on routine brain MRI studies in controls older than 30 months of age and absent in all JS patients, confirming the proposed lack of commissural fibers in JS, and accounting in part for the molar tooth sign.
American Journal of Medical Genetics Part A 07/2008; 146A(11):1389-94. · 2.39 Impact Factor
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ABSTRACT: A 15-year-old girl presented to our emergency department with dizziness, anorexia, nausea, and malaise. Clinical examination and magnetic resonance imaging studies showed characteristic features of multiple sclerosis. Surprisingly, a diagnostic lumbar puncture showed significant intracranial hypertension in addition to numerous oligoclonal bands, elevated immunoglobulin G index and immunoglobulin G/albumin ratio in the cerebrospinal fluid. It is proposed that a large burden of active demyelinating disease may cause increased intracranial pressure, thus providing an additional sound rationale for prompt therapeutic administration of intravenous high-dose steroids.
Journal of Child Neurology 07/2008; 23(6):699-702. · 1.75 Impact Factor
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ABSTRACT: Evidence-based medicine practices are widely touted in medicine, although their adoption by busy practitioners is problematic and cumbersome. In this study, we examined published evidence underpinning 2 relevant clinical management questions in pediatric epilepsy: when to initiate an antiepileptic drug and when to prescribe the ketogenic diet. We surveyed practicing child neurologists who were attending their national meeting to determine whether their current practices aligned with the evidence. Clinical studies were evaluated using the Oxford Scale, which was adopted by the American Academy of Neurology. In addition, using a novel rating approach, we examined the impact on overall recommendations by scoring results from studies refuting a given practice. The data show that child neurologists' attitudes firmly adhere to evidence-based practice on when to initiate treatment with an antiepileptic drug, but not on when to prescribe the ketogenic diet. It seems clear that important differences in attitudes of practitioners toward different management strategies for epilepsy cannot be explained only by differences in the evidence. Safety and efficacy data suggest that the ketogenic diet should be more widely adopted as a management strategy in pediatric epilepsy.
Journal of Child Neurology 06/2008; 23(5):507-14. · 1.75 Impact Factor
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ABSTRACT: To determine if hyaluronan oligomers (o-HA) antagonize the malignant properties of glioma cells and treatment-resistant glioma side population (SP) cells in vitro and in vivo.
A single intratumoral injection of o-HA was given to rats bearing spinal cord gliomas 7 days after engraftment of C6 glioma cells. At 14 days, spinal cords were evaluated for tumor size, invasive patterns, proliferation, apoptosis, activation of Akt, and BCRP expression. C6SP were isolated by fluorescence-activated cell sorting and tested for the effects of o-HA on BCRP expression, activation of Akt and epidermal growth factor receptor, drug resistance, and glioma growth in vivo.
o-HA treatment decreased tumor cell proliferation, increased apoptosis, and down-regulated activation of Akt and the expression of BCRP. o-HA treatment of C6SP inhibited activation of epidermal growth factor receptor and Akt, decreased BCRP expression, and increased methotrexate cytotoxicity. In vivo, o-HA also suppressed the growth of gliomas that formed after engraftment of C6 or BCRP+ C6SP cells, although most C6SP cells lost their expression of BCRP when grown in vivo. Interestingly, the spinal cord gliomas contained many BCRP+ cells that were not C6 or C6SP cells but that expressed nestin and/or CD45; o-HA treatment significantly decreased the recruitment of these BCRP+ progenitor cells into the engrafted gliomas.
o-HA suppress glioma growth in vivo by enhancing apoptosis, down-regulating key cell survival mechanisms, and possibly by decreasing recruitment of host-derived BCRP+ progenitor cells. Thus, o-HA hold promise as a new biological therapy to inhibit HA-mediated malignant mechanisms in glioma cells and treatment-resistant glioma stem cells.
Clinical Cancer Research 04/2008; 14(6):1804-13. · 7.74 Impact Factor
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ABSTRACT: Spinal muscular atrophy is an autosomal recessive neurodegenerative disorder that affects the motor neurons responsible for movement of the proximal muscles of the trunk and body. To date, the disease can be classified into 3 main categories based on severity and age of onset. During the October 18th symposium held in Pittsburgh, Pennsylvania, researchers met to (1) describe current diagnostic strategies, (2) discuss recent thoughts on pathogenesis, (3) review current therapies and clinical trials, and (4) define future research directions. In her opening remarks, Dr Story Landis, director of the National Institute of Neurological Disorders and Stroke, emphasized the degree to which the Neurobiology of Disease in Children conference series has broadened awareness of the many rare diseases affecting children, not only through the advancement of research but also by educating practitioners about diagnostic strategies. Dr Landis also discussed the role this conference may play in fostering research that seeks to develop a single mechanism of therapy for spinal muscular atrophy. She also discussed the current funding situation at the National Institutes of Health and addressed the crucial function of volunteer research organizations that sponsor research in further improving management of this condition. This article summarizes the presentations and includes the verbatim edited transcript of question-and-answer sessions.
Journal of Child Neurology 09/2007; 22(8):926-45. · 1.75 Impact Factor
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ABSTRACT: Spinal muscular atrophy is the second most common fatal childhood disorder. Core clinical features include muscle weakness caused by degenerating lower motor neurons and a high incidence of bone fractures and hypercalcemia. Fractures further compromise quality of life by progression of joint contractures or additional loss of motor function. Recent observations suggest that bone disease in spinal muscular atrophy may not be attributed entirely to lower motor neuron degeneration. The presence of the spinal muscular atrophy disease-determining survival motor neuron gene (SMN), SMN expression, and differential splicing in bone-resorbing osteoclasts was recently discovered. Its ubiquitous expression and the differential expression of splice variants suggest that SMN has specific roles in bone cell function. SMN protein also interacts with osteoclast stimulatory factor. Mouse models of human spinal muscular atrophy disease suggest a potential role of SMN protein in skeletal development. Dual energy x-ray absorptiometry analysis demonstrated a substantial decrease in total bone area and poorly developed caudal vertebra in the mouse model. These mice also had pelvic bone fractures. Studies delineating SMN signaling mechanisms and gene transcription in a cell-specific manner will provide important molecular insights into the pathogenesis of bone disease in children with spinal muscular atrophy. Moreover, understanding bone remodeling in spinal muscular atrophy may lead to novel therapeutic approaches to enhance skeletal health and quality of life. This article reviews the skeletal complications associated with spinal muscular atrophy and describes a functional role for SMN protein in osteoclast development and bone resorption activity.
Journal of Child Neurology 09/2007; 22(8):967-73. · 1.75 Impact Factor
