Real-time Measurement of Glial Progenitor Chemotactic Migration
Item
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Title
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Real-time Measurement of Glial Progenitor Chemotactic Migration
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Identifier
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d_2009_2013:ac5b900ec2aa:11397
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identifier
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11485
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Creator
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Able, Richard A., Jr.,
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Contributor
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Maribel Vazquez
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biochemistry | Cellular biology | Glial Progenitor Cells | Glioma | Microfluidics | Migration | TGF-alpha
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Abstract
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Gliomas are the most commonly diagnosed form of central nervous system tumors, occurring primarily in adults. Like many malignant cancers, gliomas pathologically exhibit very aggressive spreading and lead to an average diagnosed survival expectancy of twelve months. This prognosis is due in large part to the uncontrolled division and migration of malignant tumor cells within healthy brain, which makes complete surgical resection impossible. Gliomas are known to contain numerous genotypic and phenotypic alterations that affect cell proliferation and survival. Previous research has indicated that both gliomas and their precursor cells exhibit distinct migration patterns in brain tissue, which may be induced by specific cytokines and their concentration gradients. Here, we investigated the migration of four brain tumor cell (BTCs) lines (U-87 MG; U-251 MG; Daoy; and XFMPDGF) and three RCAS-infected glial progenitor cell (GPCs) populations (GPCLacZ, GPC PDGF, and GPCkRas) toward various growth factors, including but not limited to: EGF, HGF/SF, PDGF-BB, and TGF-&agr;.;Mouse neural cultures of nestin expressing glial progenitor cells that have been engineered to display the Avian Leukosis Virus (ALV) target receptor, tv-a, were infected with the RCAS viral vectors RCAS-LacZ, RCAS-PDGF-B, and RCAS-kRas, and are referred to as Ntv-a glial progenitor cells (Ntv-a-GPCs). Upon successful infection, the Ntv-a-GPCs were capable of constitutively producing beta-galactosidase, PDGF-B, and kRas, respectively. Additionally, when these viral vectors were injected into the brains of transgenic Ntv-a mouse pups, only the RCAS-PDGF-B viral titer induced gliomas (Dai et al, 2001; Holland et al, 2000). For the purpose of this work it is relevant to note that the Ntv-a cell lines used, with the exception of the XFMPDGF cells, were never injected into the mouse brain. Conversely, the XFMPDGF cell population represents an excised tumor from the brain of a ≤ 12-week-old Ntv-a transgenic mouse having the Ink4a-Arf -/- genetic background. After cranial injection with a RCAS-PDGF-B viral titer, tumors of the oligodendroglioma classification developed within 1-12 weeks in 100% of the injected mice (Tchougounova et al, 2007). We use these oligodendrogliomas as our mouse tumor model. Additionally, Daoy medulloblastomas were used to model the migration of the most common childhood human brain tumor, while the U-87 MG and U-251 MG were used to model glioblastomas, the most common adult brain tumor.;The design and characterization of our stand-alone bridged microLane system demonstrated sustained steady-state concentration gradients over 2-3 days while enabling the diffusivity measurement of 0.82 +/- 0.01 X 10 -6 cm2 / s for Dextran molecules having a molecular weight similar to growth factors examined here. A modified version of this device was then used to examine the migratory response of human MB-derived Daoy, glioblastomas, and neonatal mouse glial progenitors, which has led to the characterization of differential invasion patterns that each cell line utilizes when exposed to various growth factor concentration gradients.;This data is fundamental for understanding how BTCs and GPCs use cytokines to communicate with each other and alter cellular functions, specifically migration. Additionally, we demonstrate EGF-induced Akt activation in the migration of MB-derived Daoy cells, and the induced recruitment GPCs towards picomolar concentrations of both HGF and TGF-&agr;. We suggest based on our results that glial progenitors consisting of varying genetic background can migrate in very distinct patterns and may contribute to the selectivity of glioma recruitment/or progenitor sorting.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Biochemistry
