This work was supported with funding from the NIH (R21NS093199) and the UCLA ARC 3R's Award. Our sincerest thanks go to the lab of Dr. Harley Kornblum for provision of the HK301 and HK157 cell lines. We also thank UCLA Tissue Pathology Core Laboratory (TPCL) for cryosectioning, Advanced Light Microscopy/Spectroscopy core facility (ALMS) in California Nanosystems Institute (CNSI) at UCLA for use of the confocal microscope, UCLA Crump Institute for Molecular Imaging for using IVIS imaging system, UCLA Molecular Instrumentation Center (MIC) for providing magnetic resonance spectroscopy, and Flow Cytometry Core in Jonsson Comprehensive Cancer Center (JCCC) at UCLA for providing instrumentation for flow cytometry.

All human tissue collection steps were carried out under institutionally approved protocols.
1. Thiolation of Hyaluronic Acid
Note: Molar ratios are stated with respect to total number of carboxylate groups unless otherwise specified.
<ol>
	<li>Dissolve 500 mg of sodium hyaluronate (HA, 500-750 kDa) at 10 mg/mL in deionized, distilled water (DiH2O) in an autoclave sterilized, 250 mL Erlenmeyer flask. Stir the solution (~200 rpm) at room temperature for ...

<ol>
	<li>Xiao, W., Sohrabi, A., Seidlits, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Integrating the glioblastoma microenvironment into engineered experimental models. , (2017).</li><li>Tibbitt, M. W., Anseth, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogels+as+extracellular+matrix+mimics+for+3D+cell+culture.">Hydrogels as extracellular matrix mimics for 3D cell culture.</a> Biotechnology and bioengineering. 103 (4), 655-663 (2009).</li><li>Xiao, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brain-mimetic+3d+culture+platforms+allow+investigation+of+cooperative+effects+of+extracellular+matrix+features+on+therapeutic+resistance+in+glioblastoma.">Brain-mimetic 3d culture platforms allow investigation of cooperative effects of extracellular matrix features on therapeutic resistance in glioblastoma.</a> Cancer Research. 78 (5), 1358-1370 (2018).</li><li>Holland, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glioblastoma+multiforme:+the+terminator.">Glioblastoma multiforme: the terminator.</a> Proceedings of the National Academy of Sciences. 97 (12), 6242-6244 (2000).</li><li>Ostrom, Q. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CBTRUS+statistical+report:+primary+brain+and+central+nervous+system+tumors+diagnosed+in+the+United+States+in+2006+-+2010.">CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2006 - 2010.</a> Journal of Neuro-Oncology. 15 (6), 788-796 (2013).</li><li>Bellail, A. C., Hunter, S. B., Brat, D. J., Tan, C., Van Meir, E. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microregional+extracellular+matrix+heterogeneity+in+brain+modulates+glioma+cell+invasion.">Microregional extracellular matrix heterogeneity in brain modulates glioma cell invasion.</a> International Journal of Biochemistry and Cell Biology. 36 (6), 1046-1069 (2004).</li><li>Zamecnik, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+space+and+matrix+of+gliomas.">The extracellular space and matrix of gliomas.</a> Acta Neuropathologica. 110 (5), 435-442 (2005).</li><li>Jadin, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronan+expression+in+primary+and+secondary+brain+tumors.">Hyaluronan expression in primary and secondary brain tumors.</a> Annals of translational medicine. 3 (6), (2015).</li><li>Park, J. B., Kwak, H. J., Lee, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+hyaluronan+in+glioma+invasion.">Role of hyaluronan in glioma invasion.</a> Cell adhesion &amp; migration. 2 (3), 202-207 (2008).</li><li>Pedron, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatially+graded+hydrogels+for+preclinical+testing+of+glioblastoma+anticancer+therapeutics.">Spatially graded hydrogels for preclinical testing of glioblastoma anticancer therapeutics.</a> MRS communications. 7 (3), 442-449 (2017).</li><li>Jiglaire, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+cultures+of+glioblastoma+in+three-dimensional+hydrogel+maintain+the+original+tumor+growth+behavior+and+are+suitable+for+preclinical+drug+and+radiation+sensitivity+screening.">Ex vivo cultures of glioblastoma in three-dimensional hydrogel maintain the original tumor growth behavior and are suitable for preclinical drug and radiation sensitivity screening.</a> Experimental cell research. 321 (2), 99-108 (2014).</li><li>Florczyk, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+chitosan-hyaluronic+acid+scaffolds+as+a+mimic+of+glioblastoma+microenvironment+ECM.">Porous chitosan-hyaluronic acid scaffolds as a mimic of glioblastoma microenvironment ECM.</a> Biomaterials. 34 (38), 10143-10150 (2013).</li><li>Day, A. J., Prestwich, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronan-binding+proteins:+tying+up+the+giant.">Hyaluronan-binding proteins: tying up the giant.</a> Journal of Biological Chemistry. 277 (7), 4585-4588 (2002).</li><li>Wiranowska, M., Tresser, N., Saporta, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+interferon+and+anti-CD44+antibody+on+mouse+glioma+invasiveness+in+vitro.">The effect of interferon and anti-CD44 antibody on mouse glioma invasiveness in vitro.</a> Anticancer Research. 18 (5A), 3331-3338 (1998).</li><li>Charles, N. A., Holland, E. C., Gilbertson, R., Glass, R., Kettenmann, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+brain+tumor+microenvironment.">The brain tumor microenvironment.</a> GLIA. 59 (8), 1169-1180 (2011).</li><li>Gilg, A. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+hyaluronan+interactions+in+malignant+gliomas+and+their+drug-resistant+multipotent+progenitors.">Targeting hyaluronan interactions in malignant gliomas and their drug-resistant multipotent progenitors.</a> Clinical Cancer Research. 14 (6), 1804-1813 (2008).</li><li>Misra, S., Hascall, V. C., Markwald, R. R., Ghatak, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+between+hyaluronan+and+its+receptors+(CD44,+RHAMM)+regulate+the+activities+of+inflammation+and+cancer.">Interactions between hyaluronan and its receptors (CD44, RHAMM) regulate the activities of inflammation and cancer.</a> Frontiers in immunology. 6, 201 (2015).</li><li>Varga, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+invasion-related+extracellular+matrix+molecules+in+human+glioblastoma+versus+intracerebral+lung+adenocarcinoma+metastasis.">Expression of invasion-related extracellular matrix molecules in human glioblastoma versus intracerebral lung adenocarcinoma metastasis.</a> Zentralblatt fur Neurochirurgie. 71 (4), 173-180 (2010).</li><li>Guo, W., Giancotti, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrin+signalling+during+tumour+progression.">Integrin signalling during tumour progression.</a> Nature Reviews Molecular Cell Biology. 5 (10), 816-826 (2004).</li><li>Bello, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#945;v&#946;3+and+&#945;v&#946;5+integrin+expression+in+glioma+periphery.">&#945;v&#946;3 and &#945;v&#946;5 integrin expression in glioma periphery.</a> Neurosurgery. 49 (2), 380-390 (2001).</li><li>Chamberlain, M. C., Cloughsey, T., Reardon, D. A., Wen, P. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+treatment+for+glioblastoma:+integrin+inhibition.">A novel treatment for glioblastoma: integrin inhibition.</a> Expert review of neurotherapeutics. 12 (4), 421-435 (2012).</li><li>Chopra, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Augmentation+of+integrin-mediated+mechanotransduction+by+hyaluronic+acid.">Augmentation of integrin-mediated mechanotransduction by hyaluronic acid.</a> Biomaterials. 35 (1), 71-82 (2014).</li><li>Kim, Y., Kumar, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD44-mediated+adhesion+to+hyaluronic+acid+contributes+to+mechanosensing+and+invasive+motility.">CD44-mediated adhesion to hyaluronic acid contributes to mechanosensing and invasive motility.</a> Molecular Cancer Research. 12 (10), 1416-1429 (2014).</li><li>Joo, K. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-specific+orthotopic+glioblastoma+xenograft+models+recapitulate+the+histopathology+and+biology+of+human+glioblastomas+in+situ.">Patient-specific orthotopic glioblastoma xenograft models recapitulate the histopathology and biology of human glioblastomas in situ.</a> Cell Reports. 3 (1), 260-273 (2013).</li><li>Oh, Y. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translational+validation+of+personalized+treatment+strategy+based+on+genetic+characteristics+of+glioblastoma.">Translational validation of personalized treatment strategy based on genetic characteristics of glioblastoma.</a> PloS one. 9 (8), e103327 (2014).</li><li>Pedron, S., Becka, E., Harley, B. A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+glioma+cell+phenotype+in+3D+matrices+by+hyaluronic+acid.">Regulation of glioma cell phenotype in 3D matrices by hyaluronic acid.</a> Biomaterials. 34 (30), 7408-7417 (2013).</li><li>Wang, C., Tong, X., Yang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioengineered+3D+brain+tumor+model+to+elucidate+the+effects+of+matrix+stiffness+on+glioblastoma+cell+behavior+using+PEG-based+hydrogels.">Bioengineered 3D brain tumor model to elucidate the effects of matrix stiffness on glioblastoma cell behavior using PEG-based hydrogels.</a> Molecular pharmaceutics. 11 (7), 2115-2125 (2014).</li><li>Zhu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioactive+modification+of+poly(ethylene+glycol)+hydrogels+for+tissue+engineering.">Bioactive modification of poly(ethylene glycol) hydrogels for tissue engineering.</a> Biomaterials. 31 (17), 4639-4656 (2010).</li><li>Stern, R., Asari, A. A., Sugahara, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyaluronan+fragments:+an+information-rich+system.">Hyaluronan fragments: an information-rich system.</a> European journal of cell biology. 85 (8), 699-715 (2006).</li><li>Riddles, P. W., Blakeley, R. L., Zerner, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ellman's+reagent:+5,+5&#8242;-dithiobis+(2-nitrobenzoic+acid)-a+reexamination.">Ellman's reagent: 5, 5&#8242;-dithiobis (2-nitrobenzoic acid)-a reexamination.</a> Analytical biochemistry. 94 (1), 75-81 (1979).</li><li>Jin, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characterization+of+hyaluronic+acid-poly+(ethylene+glycol)+hydrogels+via+Michael+addition:+An+injectable+biomaterial+for+cartilage+repair.">Synthesis and characterization of hyaluronic acid-poly (ethylene glycol) hydrogels via Michael addition: An injectable biomaterial for cartilage repair.</a> Acta biomaterialia. 6 (6), 1968-1977 (2010).</li><li>Ozawa, T., James, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishing+intracranial+brain+tumor+xenografts+with+subsequent+analysis+of+tumor+growth+and+response+to+therapy+using+bioluminescence+imaging.">Establishing intracranial brain tumor xenografts with subsequent analysis of tumor growth and response to therapy using bioluminescence imaging.</a> Journal of visualized experiments. 41, 3-7 (2010).</li></ol>

The authors declare that they have no competing financial interests.

Generation of reproducible data using this 3D culture system requires: 1) consistent batch-to-batch thiolation of HA, 2) practice to achieve efficient mixing of hydrogel precursors and handling of hydrogel cultures to prevent damage and 3) optimized seeding density for each cell line used.
When a particular weight percentage of HA is desired in the hydrogel, the degree of thiolation of HA determines the crosslink density. We recommend using a consistent amount of HA for each thiolation reactio...

Three-dimensional (3D) culture systems recapitulate interactions between cells and their surrounding extracellular matrix (ECM) in native tissues better than their two-dimensional (2D) counterparts1,2. Advancements in tissue engineering have yielded sophisticated, 3D culture platforms that enable controlled investigations into 1) how chemical and physical components of the matrix microenvironment affect cell behaviors and 2) efficacy of new therapeutic strategies for a number of diseases, including cancers2. While in vitro models cannot account for systemic factors, such as endocrine and immune signals, and thus cannot completely replace in vivo models, they provide several advantages including reproducibility, experimental control, affordability and speed. Here, we describe the use of brain-mimetic hydrogels in which 3D cultures of patient-derived brain tumor cells capture many aspects of tumor physiology, in particular, the dynamics of acquiring treatment resistance3. Compared to other in vitro methods, these cultures better represent in vivo tumor models and clinical observations3.
Glioblastoma (GBM) is the most frequent and lethal cancer originating in the brain, with a median survival of only 1-2 years4,5. In recent years, many studies have focused on the influence of tumor matrix environment in GBM6,7,8. The unique brain ECM has been reported to affect GBM cell migration, proliferation, and therapeutic resistance6,7,8,9,10,11,12. Hyaluronic acid (HA) is an abundant glycosaminoglycan (GAG) in the brain, where it interacts with other GAGs and proteoglycans to form a hydrogel-like mesh13. Many studies have reported HA overexpression in GBM tumors and its subsequent effects on cancer progression8,9,13,14,15,16,17. Other ECM components also affect GBM tumor growth and invasion6,7,15,18. For example, fibronectin and vitronectin, which are typically overexpressed in GBM, induce heterodimerization of cell surface integrin receptors through binding to the &#34;RGD&#34; sequence and initiate complex signaling cascades that promote tumor survival19,20,21. Besides biochemical influences, physical properties of the tissue matrix also affect GBM progression22,23.
Continual acquisition of resistance to therapies is one of the main drivers of GBM lethality4. Drugs showing promising results in 2D or gliomasphere models have failed in subsequent animal studies and clinical cases3, indicating that the effects of microenvironmental factors significantly contributed to GBM tumor response1. While animal models can provide a 3D, physiologically appropriate microenvironment to xenografted patient cells and generate clinically relevant outcomes24,25, the complexity of the brain microenvironment in vivo makes it challenging to determine which features, including cell-matrix interactions, are key to specific biological outcomes. Identification of new therapeutic targets will benefit from the use of simplified culture platforms in which biochemical and biophysical properties are defined.
Unlike previously reported biomaterial models of the GBM tumor microenvironment26,27 which have not achieved true orthogonal control over individual biochemical and physical features of the ECM, the biomaterial platform reported here enables decoupling of the contributions of multiple independent features to GBM cell phenotype. Here, we present an HA-based, orthogonally tunable, hydrogel system for 3D culture of patient-derived GBM cells. Hydrogels are formed from two polymer components: 1) biologically active HA and 2) biologically inert polyethylene glycol (PEG). PEG is a widely used biocompatible and hydrophilic material with low protein adsorption and minimal immunogenicity28. Here, approximately 5% of glucuronic acid moieties on HA chains are functionalized with thiol groups to enable crosslinking to a commercially available 4-arm-PEG terminated with maleimides via Michael-type addition. In its most common form in the body, HA exists in high molecular weight (HMW) chains. Here, a low degree of modification of HMW HA (500-750 kDa) helps to preserve native interactions of HA and its cell receptors, including CD4429. By substituting PEG-thiol for HA-thiol while maintaining a constant molar ratio of total thiols to maleimides, HA concentration can be decoupled from mechanical properties of the resulting hydrogels. Furthermore, stoichiometric controls can be used to conjugate cysteine-terminated peptides to a defined average number of maleimide-terminated arms on each 4-arm-PEG. Incorporation of ECM-derived, adhesive peptides enables interactions with integrins on cultured cells, through which biochemical and chemical signals are transduced1. Maleimide-thiol addition occurs very quickly under physiological conditions, minimizing the time required for cell encapsulation and maximizing survival of patient-derived cells. Moreover, hydrogel cultures can be treated like typical tissue specimen and are compatible with standard characterization techniques including Western blotting, flow cytometry, and immunofluorescence staining. The following protocol describes the procedures for fabricating hydrogels, establishing 3D cultures of patient-derived GBM cells and techniques for biochemical analysis.

<table border="0" cellpadding="0" cellspacing="0" style="width:2204px;" width="2203">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">pH meter</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">N/A</td>
			<td style="width:1579px;">Any pH meter that has pH 2-10 sensitivity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Stir plate</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">N/A</td>
			<td>General lab equipment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Erlenmeyer flask (125mL)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">FB-501-125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">dialysis tubes</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">21-152-14</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">2L polypropylene beaker</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">S01916</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">sodium hyaluronan</td>
			<td style="width:136px;">Lifecore</td>
			<td style="width:121px;">HA700k-5</td>
			<td>500-750 kDa range</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">PI-22980</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">N-hydroxysuccinimide (NHS)</td>
			<td style="width:136px;">sigma aldrich</td>
			<td style="width:121px;">130672-5G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Hydrochloric acid (HCl)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">SA48-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Sodium hydroxide (NaOH)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">SS266-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Cystamine dihydrochloride</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">AC111770250</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Dithiolthreitol (DTT)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">BP172-25</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:368px;">Ellman&#39;s test reagent (5-(3-Carboxy-4-nitrophenyl)disulfanyl-2-nitrobenzoic acid</td>
			<td style="width:136px;">Sigma Aldrich</td>
			<td style="width:121px;">D218200-1G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Deuterated water (deuterium oxide)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">AC166301000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">0.22&#181;m vacuum driven filter</td>
			<td style="width:136px;">CellTreat</td>
			<td style="width:121px;">229706</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Phosphate buffered saline (PBS)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">P32080-100T</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Hanks&#39; balanced salt saline (HBSS)</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">MT-21-022-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">4-arm-PEG-maleimide</td>
			<td style="width:136px;">JenKem Technology</td>
			<td style="width:121px;">A7029-1</td>
			<td>molecular weight around 20kDa</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">4-arm-PEG-thiol</td>
			<td style="width:136px;">JenKem Technology</td>
			<td style="width:121px;">A7039-1</td>
			<td>molecular weight around 20kDa</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">L-Cysteine&#160;</td>
			<td style="width:136px;">sigma aldrich</td>
			<td style="width:121px;">C7880-100G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">RGD ECM mimetic peptide</td>
			<td style="width:136px;">Genscript Biotech</td>
			<td style="width:121px;">N/A</td>
			<td>Custom peptide with sequence &#34;GCGYGRGDSPG&#34;, N-terminal should be acetylated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">silicone molds</td>
			<td style="width:136px;">Sigma Aldrich</td>
			<td style="width:121px;">GBL664201-25EA</td>
			<td>Use razor blade to cut into single pieces</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">complete culture medium</td>
			<td style="width:136px;">Various</td>
			<td style="width:121px;">Various</td>
			<td>DMEM/F12 (Thermofisher) with non-serum supplement (G21 from GeminiBio), epidermal growth factor 50ng/mL (Peprotech), fibroblast growth factor 20ng/mL (Pepro Tech) and heprain 25&#181;g/mL (Sigma Aldrich), culture medium varies in different labs</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">patient derived GBM cell</td>
			<td style="width:136px;">N/A</td>
			<td style="width:121px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">20G needle</td>
			<td style="width:136px;">BD medical</td>
			<td style="width:121px;">305175</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">1mL syringe</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">14-823-434</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">10mL syringe</td>
			<td style="width:136px;">BD medical</td>
			<td style="width:121px;">302995</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">RIPA Buffer</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">PI-89901</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">protease/phosphatase inhibitor mini tablet</td>
			<td style="width:136px;">sigma aldrich</td>
			<td style="width:121px;">5892970001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">vortex shaker</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">12-814-5Q</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">TrypLE express</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">12604013</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">70&#181;m cell strainer</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">22-363-548</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Paraformaldehyde</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">AC416785000</td>
			<td>Dissolve 4% (w/v) in PBS, keep pH 7.4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">D-sucrose</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">BP220-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Optimal Cutting Temperature (O.C.T.) compound</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">NC9373881</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Cell culture incubator</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">N/A</td>
			<td>Any General One with 5% CO2 and 37C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">fridge/freezer</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">N/A</td>
			<td>Any General Lab equipment with -20C and -80C capacity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Disposable embedding molds</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">12-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Lyapholizer</td>
			<td style="width:136px;">Labconco</td>
			<td style="width:121px;">N/A</td>
			<td>Any -105C freeze dryers</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">HEPES</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">BP310-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Amber vial</td>
			<td style="width:136px;">Kimble Chase</td>
			<td style="width:121px;">60912D-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Wide orifice pipette tips</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">9405120</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">2-methylbutane</td>
			<td style="width:136px;">Thermo Fisher</td>
			<td style="width:121px;">03551-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:368px;">Dry Ice</td>
			<td style="width:136px;">N/A</td>
			<td style="width:121px;">N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

hyaluronic-acid based hydrogels for 3-dimensional culture of patient-derived glioblastoma cells

Glioblastoma (GBM) is the most common, yet most lethal, central nervous system cancer. In recent years, many studies have focused on how the extracellular matrix (ECM) of the unique brain environment, such as hyaluronic acid (HA), facilitates GBM progression and invasion. However, most in vitro culture models include GBM cells outside of the context of an ECM. Murine xenografts of GBM cells are used commonly as well. However, in vivo models make it difficult to isolate the contributions of individual features of the complex tumor microenvironment to tumor behavior. Here, we describe an HA hydrogel-based, three-dimensional (3D) culture platform that allows researchers to independently alter HA concentration and stiffness. High molecular weight HA and polyethylene glycol (PEG) comprise hydrogels, which are crosslinked via Michael-type addition in the presence of live cells. 3D hydrogel cultures of patient-derived GBM cells exhibit viability and proliferation rates as good as, or better than, when cultured as standard gliomaspheres. The hydrogel system also enables incorporation of ECM-mimetic peptides to isolate effects of specific cell-ECM interactions. Hydrogels are optically transparent so that live cells can be imaged in 3D culture. Finally, HA hydrogel cultures are compatible with standard techniques for molecular and cellular analyses, including PCR, Western blotting and cryosectioning followed by immunofluorescence staining.

For each batch of thiolated HA, the degree of thiolation should be verified using H1-NMR or an Ellman&#39;s test. HA modification using the procedure described here consistently generates ~5% thiolation (defined as the molar ratio of thiols to HA disaccharides) (Figure 1).
Setting up this new culture platform will require each laboratory to perform rigorous testing to ens...

Watch this Scientific Journal Video about Hyaluronic-Acid Based Hydrogels for 3-Dimensional Culture of Patient-Derived Glioblastoma Cells at JoVE.com

Hyaluronic-Acid Based Hydrogels for 3-Dimensional Culture of Patient-Derived Glioblastoma Cells

Here, we present a protocol for three-dimensional culture of patient-derived glioblastoma cells within orthogonally tunable biomaterials designed to mimic the brain matrix. This approach provides an in vitro, experimental platform that maintains many characteristics of in vivo glioblastoma cells typically lost in culture.

Glioblastoma (GBM) is the most common, yet most lethal, central nervous system cancer. In recent years, many studies have focused on how the extracellular ...

This method can help answer key questions about glioblastoma tumors and how the extracellular matrix can facilitate treatment resistance. This technique enables modular construction of adaptable 3D cell culture platforms which can be used to culture patient-derived glioblastoma cells in an environment that better approximates native brain. To begin, place clean dry silicone rubber molds into each well of a non-tissue culture treated 12-well plate and use the clean blunt end of a pipette tip to adhere the molds to the bottom of the plate.After checking the seal between the molds and the well bottoms, collect the dissociated gliomaspheres from a glioblastoma cell culture by centrifugation and re-suspend the pellet in one milliliter of cell dissociation enzyme. After five minutes at room temperature, agitate the tube with gentle tapping and arrest the enzymatic reaction with four milliliters of complete medium. Centrifuge the cells again and re-suspend the pellet in one milliliter of fresh complete medium before straining the cells through a 70 micrometer filter.Wash the strainer with an additional four milliliters of complete medium and split the suspension into two aliquots of eight times 10 to the fourth cells per centrifuge tube. Collect the cells by centrifugation and re-suspend one pellet in 80 microliters of freshly prepared polyethylene glycol maleimide or PEG-Mal-RGD and one pellet in 80 microliters of freshly prepared PEG-Mal-CYS solution per mold. Using a 200 microliter wide orifice micropipette tip, add 40 microliters of hyaluronic acid solution into each rubber silicone mold, followed by 40 microliters of either the PEG-Mal-CYS or PEG-Mal-RGD cell solution.Quickly pipetting up and down no more than 10 times per mold to mix. Because of the rapid gelation time, once the two hydrogel components are mixed, it is important to use a wide orifice pipette tip to mix the solutions together quickly yet thoroughly. This step requires practice.Then, place the gel encapsulated cells into a 37 degrees celsius and 5%CO2 cell culture incubator for five to 10 minutes. At the end of the incubation, add two to two and a half milliliters of culture medium to each gel and use a sterile two microliter pipette tip and forceps to gently separate the gels from the sides of the molds. Then, use sterilized forceps to remove the molds from the plate wells and return the plate to the cell incubator.For single cell extraction, at the appropriate experimental endpoint, remove the supernatant from the wells and transfer the gel culture from each well into individual 1.5 milliliter microcentrifuge tubes. Incubate the gels with 500 microliters of cell dissociation enzyme for five minutes at 37 degrees celsius with occasional flicking and transfer the mixtures into individual 50 milliliter centrifuge tubes containing five milliliters of complete medium per tube on ice. Next, use a 10 milliliter syringe equipped with a 20-gauge needle to gently aspirate each cell suspension through the needle tip eight times and filter the mixtures through a 70 micrometer cell strainer into new 50 milliliter centrifuge tubes.When dissociating cells from the hydrogel, make sure to depress the syringe plunger slowly to avoid sheering which can compromise cell membrane integrity. Wash the strainers with five milliliters of fresh medium and collect the cells by centrifugation. Then, re-suspend the pellets in the appropriate flow cytometry buffer for staining and sorting according to standard protocols.To cryopreserve the hydrogels for sectioning, remove the supernatant from the plate wells and incubate the gel cultures with two milliliters of 4%paraformaldehyde at four degrees celsius overnight. The next morning, replace the fixative with two milliliters of 5%sucrose in PBS for a one hour incubation at room temperature. At the end of the incubation, replace the 5%sucrose with two milliliters of 20%sucrose in PBS for two 30 minute incubations at room temperature.After the second 30 minute incubation, refresh the 20%sucrose one more time for a four degrees celsius incubation overnight. The next morning, gently replace the sucrose in PBS solution with 20%sucrose in optimal cutting temperature or OCT medium taking care to cover each gel entirely and place the plate at four degrees celsius for an additional three hours. At the end of the incubation, use a large flat spatula to carefully transfer each gel into the center of an embedding mold and fill the embedding molds with pure OCT to just below the top edges of the molds.Then, freeze the hydrogel samples in cooled 2-methylbutane and section the hydrogel samples on a cryostat according to standard protocols. Seating 80 microliter hydrogels to a four times 10 to the fourth cells per gel density, consistently results in proliferation rates that are comparable to, or better than, gliomasphere cultures. For example, four days after encapsulation, glioblastoma cells in RGD containing hydrogels exhibit an invasive phenotype while cells cultured in hydrogel using PEG-Mal-CYS demonstrate a spherical morphology.These robust cultures allow the evaluation of the effects of reagents like soluble cyclo RGD which competitively disrupt interactions of cells with RGD incorporated into hydrogels. Using bioluminescence imaging, relative numbers of viable cells can be observed in hydrogel cultures, for example, during the course of a 12 day erlotinib treatment. Western blot analysis of cleaved poly ADP polymerase indicates that the relative degree of apoptosis in treated CD44 knockdown cells is higher than that observed in wildtype glioblastoma cells cultured in 0.5%hyaluronic acid hydrogels.In addition, cryosections of hydrogel based 3D cultures preserve extracellular matrix deposited by the cultured cells. For example, allowing analysis of the deposition patterns of type four collagen shifts upon erlotinib treatment. When attempting this procedure, it is important to evaluate the degree of thiolation of each batch of hyaluronic acid.It is also important to make up fresh precursor solutions for each time you do a cell encapsulation experiment. Development of this technique has paved the way for cancer researchers to evaluate the efficacy of new and existing treatments and to explore the mechanisms of treatment resistance and brain cancer progression, all using an ex vivo model.

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12.8K Views.  University of California, Los Angeles. This method can help answer key questions about glioblastoma tumors and how the extracellular matrix can facilitate treatment resistance. This technique enables modular construction of adaptable 3D cell culture platforms which can be used to culture patient-derived glioblastoma cells in an environment that better approximates native brain. To begin, place clean dry silicone rubber molds into each well of a non-tissue culture treated 12-well plate and use the clean blunt end of a pipette tip t...