Dataset Information

Glioma Cell Invasion is Significantly Enhanced in Composite Hydrogel Matrices Composed of Chondroitin 4- and 4,6-Sulfated Glycosaminoglycans.

ABSTRACT: Glioblastoma multiforme (GBM) is the most aggressive form of astrocytoma accounting for a majority of primary malignant brain tumors in the United States. Chondroitin sulfate proteoglycans (CSPGs) and their glycosaminoglycan (GAG) side chains are key constituents of the brain extracellular matrix (ECM) implicated in promoting tumor invasion. However, the mechanisms by which sulfated CS-GAGs promote brain tumor invasion are currently unknown. We hypothesize that glioma cell invasion is triggered by the altered sulfation of CS-GAGs in the tumor extracellular environment, and that this is potentially mediated by independent mechanisms involving CXCL12/CXCR4 and LAR signaling respectively. This was tested in vitro by encapsulating the human glioma cell line U87MG-EGFP into monosulfated (4-sulfated; CS-A), composite (4 and 4,6-sulfated; CS-A/E), unsulfated hyaluronic acid (HA), and unsulfated agarose (AG; polysaccharide) hydrogels within microfluidics-based choice assays. Our results demonstrated the enhanced preferential cell invasion into composite hydrogels, when compared to other hydrogel matrices (p<0.05). Haptotaxis assays demonstrated the significantly (p<0.05) faster migration of U87MG-EGFP cells in CXCL12 containing CS-GAG hydrogels when compared to other hydrogel matrices containing the same chemokine concentration. This is likely due to the significantly (p<0.05) greater affinity of composite CS-GAGs to CXCL12 over other hydrogel matrices. Results from qRT-PCR assays further demonstrated the significant (p<0.05) upregulation of the chemokine receptor CXCR4, and the CSPG receptor LAR in glioma cells within CS-GAG hydrogels compared to control hydrogels. Western blot analysis of cell lysates derived from glioma cells encapsulated in different hydrogel matrices further corroborate qRT-PCR results, and indicate the presence of a potential variant of LAR that is selectively expressed only in glioma cells encapsulated in CS-GAG hydrogels. These results suggest that sulfated CS-GAGs may directly induce enhanced invasion and haptotaxis of glioma cells associated with aggressive brain tumors via distinct mechanisms.

SUBMITTER: Logun MT

PROVIDER: S-EPMC5312825 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Glioma Cell Invasion is Significantly Enhanced in Composite Hydrogel Matrices Composed of Chondroitin 4- and 4,6-Sulfated Glycosaminoglycans.

Logun Meghan T MT Bisel Nicole S NS Tanasse Emily A EA Zhao Wujun W Gunasekera Bhagya B Mao Leidong L Karumbaiah Lohitash L

Journal of materials chemistry. B 20160826 36

Glioblastoma multiforme (GBM) is the most aggressive form of astrocytoma accounting for a majority of primary malignant brain tumors in the United States. Chondroitin sulfate proteoglycans (CSPGs) and their glycosaminoglycan (GAG) side chains are key constituents of the brain extracellular matrix (ECM) implicated in promoting tumor invasion. However, the mechanisms by which sulfated CS-GAGs promote brain tumor invasion are currently unknown. We hypothesize that glioma cell invasion is triggered ...[more]

PMID: 28217304

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Project description:In this study, two respective groups of RNA aptamers have been selected against two main classes of glycosaminoglycans (GAGs), heparosan, and chondroitin, as they have proven difficult to specifically detect in biological samples. GAGs are linear, anionic, polydisperse polysaccharides found ubiquitously in nature, yet their detection remains problematic. GAGs comprised repeating disaccharide units, consisting of uronic acid and hexosamine residues that are often also sulfated at various positions. Monoclonal antibodies are frequently used in biology and medicine to recognize various biological analytes with high affinity and specificity. However, GAGs are conserved across the whole animal phylogenic tree and are nonimmunogenic in hosts traditionally used for natural antibody generation. Thus, it has been challenging to obtain high affinity, selective antibodies that recognize various GAGs. In the absence of anti-GAG antibodies, glycobiologists have relied on the use of specific enzymes to convert GAGs to oligosaccharides for analysis by mass spectrometry. Unfortunately, while these methods are sensitive, they can be labor-intensive and cannot be used for in situ detection of intact GAGs in cells and tissues. Aptamers are single-stranded oligonucleotide (DNA or RNA) ligands capable of high selectivity and high affinity detection of biological analytes. Aptamers can be developed in vitro by the systematic evolution of ligands by exponential enrichment (SELEX) to recognize nonimmunogenic targets, including neutral carbohydrates. This study utilizes the SELEX method to generate RNA aptamers, which specifically bind to the unmodified GAGs, heparosan, and chondroitin. Binding confirmation and cross-screening with other GAGs were performed using confocal microscopy to afford three specific GAGs to each target. Affinity constant of each RNA aptamer was obtained by fluorescent output after interaction with the respective GAG target immobilized on plates; the K D values were determined to be 0.71-1.0 μM for all aptamers. Upon the success of chemical modification (to stabilize RNA aptamers in actual biological systems) and fluorescent tagging (to only visualize RNA aptamers) of these aptamers, they would be able to serve as a specific detection reagent of these important GAGs in biological samples.

Dataset Information

Glioma Cell Invasion is Significantly Enhanced in Composite Hydrogel Matrices Composed of Chondroitin 4- and 4,6-Sulfated Glycosaminoglycans.

Publications

Glioma Cell Invasion is Significantly Enhanced in Composite Hydrogel Matrices Composed of Chondroitin 4- and 4,6-Sulfated Glycosaminoglycans.

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