Name: monitoring cancer cell invasion and t-cell cytotoxicity in 3d culture
Uploaded: 2020-06-23T14:45:00
Description: Watch this Scientific Journal Video about Monitoring Cancer Cell Invasion and T-Cell Cytotoxicity in 3D Culture at JoVE.com

We thank Virginie Ory, PhD for helpful discussions and advice on the approach of the 3D co-culture model. We also thank Elizabeth Jones for excellent technical assistance with the IHC sectioning. This study was supported by grants from the DFG (Deutsche Forschungsgemeinschaft) to YL (LI 2547/4-1) and the National Institutes of Health to AW (R01 CA231291), to ATR (R01 CA205632), to GWP (R01 CA218670), and the Core Grant of the Cancer Center (P30 CA51008).

A list and explanation of some frequently used words throughout the protocol can be found in Supplementary File 1.
1. Generation of spheroids
<ol>
	<li>Prepare and autoclave 2% agarose in 1x PBS (e.g., 1 g agarose in 50 mL of 1x PBS) and autoclave 35- and 81-microwell rubber molds. 
	CAUTION: Avoid using low-melting agarose for generating the agarose casts for IHC processing.</li>
	<li>Prepare agarose casts 
	NOTE: 35-microwell casts are used for invasion, immunofl...

<ol>
	<li>Chen, D. S., Mellman, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elements+of+cancer+immunity+and+the+cancer-immune+set+point.">Elements of cancer immunity and the cancer-immune set point.</a> Nature. 541 (7637), 321-330 (2017).</li><li>Sharma, P., Allison, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissecting+the+mechanisms+of+immune+checkpoint+therapy.">Dissecting the mechanisms of immune checkpoint therapy.</a> Nature Reviews Immunology. 20 (2), 75-76 (2020).</li><li>Blomberg, O. S., Spagnuolo, L., de Visser, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune+regulation+of+metastasis:+mechanistic+insights+and+therapeutic+opportunities.">Immune regulation of metastasis: mechanistic insights and therapeutic opportunities.</a> Disease Model Mechanisms. 11 (10), (2018).</li><li>Schmeichel, K. L., Bissell, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+tissue-specific+signaling+and+organ+function+in+three+dimensions.">Modeling tissue-specific signaling and organ function in three dimensions.</a> Journal of Cell Science. 116 (12), 2377-2388 (2003).</li><li>Kramer, N., 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=In+vitro+cell+migration+and+invasion+assays.">In vitro cell migration and invasion assays.</a> Mutation Research. 752 (1), 10-24 (2013).</li><li>xu, x., Farach-Carson, M. C., Jia, x. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+In+vitro+tumor+models+for+cancer+research+and+drug+evaluation.">Three-dimensional In vitro tumor models for cancer research and drug evaluation.</a> Biotechnology Advances. 32 (7), 1256-1268 (2014).</li><li>Lamichhane, S. P., 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=Recapitulating+epithelial+tumor+microenvironment+In+vitro+using+three+dimensional+tri-culture+of+human+epithelial,+endothelial,+and+mesenchymal+cells.">Recapitulating epithelial tumor microenvironment In vitro using three dimensional tri-culture of human epithelial, endothelial, and mesenchymal cells.</a> BioMed Central Cancer. 16 (581), (2016).</li><li>Klimkiewicz, K., 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=A+3D+model+of+tumour+angiogenic+microenvironment+to+monitor+hypoxia+effects+on+cell+interactions+and+cancer+stem+cell+selection.">A 3D model of tumour angiogenic microenvironment to monitor hypoxia effects on cell interactions and cancer stem cell selection.</a> Cancer Letters. 396, 10-20 (2017).</li><li>Cavo, 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=Microenvironment+complexity+and+matrix+stiffness+regulate+breast+cancer+cell+activity+in+a+3D+In+vitro+model.">Microenvironment complexity and matrix stiffness regulate breast cancer cell activity in a 3D In vitro model.</a> Scientific Reports. 6, 35367 (2016).</li><li>Martinez, N. J., Titus, S. A., Wagner, A. K., Simeonov, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+throughput+fluoresecent+imaging+approaches+for+drug+discovery+using+In+vitro+and+in+vivo+three-dimensional+models.">High throughput fluoresecent imaging approaches for drug discovery using In vitro and in vivo three-dimensional models.</a> Expert Opinion on Drug Discovery. 10 (12), 1347-1361 (2015).</li><li>Zanoni, 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=3D+tumor+spheroid+models+for+In+vitro+therapeutic+screening:+a+systematic+approach+to+enhance+the+biological+relevance+of+data+obtained.">3D tumor spheroid models for In vitro therapeutic screening: a systematic approach to enhance the biological relevance of data obtained.</a> Scientific Reports. 11 (6), 19103 (2016).</li><li>Veelken, C., Bakker, G., Drell, D., Friedl, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+cell-based+automated+quantification+of+therapy+responses+of+invasive+cancer+spheroids+in+organotypic+3D+culture.">Single cell-based automated quantification of therapy responses of invasive cancer spheroids in organotypic 3D culture.</a> Methods. 1 (128), 139-149 (2017).</li><li>Puls, T. 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=Development+of+a+Novel+3D+Tumor-tissue+Invasion+Model+for+High-throughput,+High-content+Phenotypic+Drug+Screening.">Development of a Novel 3D Tumor-tissue Invasion Model for High-throughput, High-content Phenotypic Drug Screening.</a> Scientific Reports. 8 (1), 13039 (2018).</li><li>Jenkins, R. 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=Ex+Vivo+Profiling+of+PD-1+Blockade+Using+Organotypic+Tumor+Spheroids.">Ex Vivo Profiling of PD-1 Blockade Using Organotypic Tumor Spheroids.</a> Cancer Discovery. 8 (2), 196-215 (2018).</li><li>Berens, E. B., Holy, J. M., Riegel, A. T., Wellstein, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Cancer+Cell+Spheroid+Assay+to+Assess+Invasion+in+a+3D+Setting.">A Cancer Cell Spheroid Assay to Assess Invasion in a 3D Setting.</a> Journal of Visualized Experiments. 20 (105), (2015).</li><li>Shoval, H., 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=Tumor+cells+and+their+crosstalk+with+endothelial+cells+in+3D+spheroids.">Tumor cells and their crosstalk with endothelial cells in 3D spheroids.</a> Scientific Reports. 7 (1), 10428 (2017).</li><li>Giannattasio, 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=Cytotoxicity+and+infiltration+of+human+NK+cells+in+in+vivo-like+tumor+spheroids.">Cytotoxicity and infiltration of human NK cells in in vivo-like tumor spheroids.</a> BioMed Central Cancer. 3 (15), 351 (2015).</li><li>Friedl, P., Wolf, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour-cell+invasion+and+migration:+diversity+and+escape+mechanisms.">Tumour-cell invasion and migration: diversity and escape mechanisms.</a> Nature Reviews Cancer. 3 (5), 362-374 (2003).</li><li>McLennan, 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=Neural+crest+migration+is+driven+by+a+few+trailblazer+cells+with+a+unique+molecular+signature+narrowly+confined+to+the+invasive+front.">Neural crest migration is driven by a few trailblazer cells with a unique molecular signature narrowly confined to the invasive front.</a> Development. 142 (11), 2014-2025 (2015).</li><li>Coffey, A., Johnson, M. D., Berry, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SpOT+the+Correct+Tissue+Every+Time+in+Multi-tissue+Blocks.">SpOT the Correct Tissue Every Time in Multi-tissue Blocks.</a> Journal of Visualized Experiments. (99), e52868 (2015).</li><li>Brenner, 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=Differential+inhibition+of+renal+cancer+cell+invasion+mediated+by+fibronectin,+collagen+IV+and+laminin.">Differential inhibition of renal cancer cell invasion mediated by fibronectin, collagen IV and laminin.</a> Cancer Letters. 155 (2), 199-205 (2000).</li><li>Farhat, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA+Extraction+from+Collagen+Gels+Using+Qiagen's+RNeasy+Kit.">RNA Extraction from Collagen Gels Using Qiagen's RNeasy Kit.</a> The Protocol Place. 2012, (2019).</li><li>Foty, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+hanging+drop+cell+culture+protocol+for+generation+of+3D+spheroids.">A simple hanging drop cell culture protocol for generation of 3D spheroids.</a> Journal of Visualized Experiments. (51), e2720 (2011).</li></ol>

The method presented here describes 3D tumor spheroid generation, which allows co-culture with T-cells, cell-based functional and molecular assays, as well as a variety of monitoring and analysis possibilities using a single device. The major advantage of our approach is that it does not necessitate transfer of the 3D culture to a separate assay and maintains the integrity of the 3D culture throughout the assays.
The workflow presented here can be modified as needed. The incubation times for s...

Despite significant improvements in cancer immunotherapy over the past decade, our mechanistic understanding of sensitivity and resistance to treatments are still fairly poor1. It is well-established that tumors display substantial heterogeneity, and that the dynamic interactions of the tumor cells with their microenvironment as well as with the immune cells, impact tumor cell death, invasive behavior and response to treatments that include immunotherapy1,2,3. As one arm of the adaptive immune system, T-cells execute cell-specific cytotoxicity. The analysis of T-cell recognition and response to cancer cells provides mechanistic insights into resistance and sensitivity to immune modulatory treatments.
In vitro modeling and monitoring interactions between cancer and T-cells in an appropriate environment has been challenging and so far, resulted in limited mechanistic insights. Most cell-based assays rely on a two-dimensional (2D) environment, that lacks key features that are critical for recapitulating the three-dimensional (3D) in vivo physiology4,5,6, namely spatial cell-cell interactions, contact with the extracellular matrix (ECM)7, dynamic metabolic demand, increased hypoxia due to mass growth8, and effects of the tumor microenvironment (TME)9. On the other hand, there are still a number of shortcomings with the currently used three-dimensional (3D) co-culture and invasion assay systems: (1) the time consuming nature of spheroid generation and harvest5,10, (2) the lack of control over spheroid size, shape and cell density11,12, (3) the low-throughput type assays, (4) the requirement for special equipment13,14, (5) the need to transfer the co-culture into distinct environments for different assays15,16,17. In particular, transferring of a co-culture assay often leads to disruption of spheroids and loss of the co-culture integrity. This applies especially for &#8220;loose&#8221; spheroids with reduced cell-cell adhesion. For example, most 3D invasion assays require that spheroids are harvested after their initial formation and then resuspended in ECM14,15,16. This resuspension step results in a loss of control over the distance between spheroids. Since distance between tumor spheroids impacts their invasive behavior, this loss of control introduces high inter-assay variance and reduces the reproducibility. Furthermore, the application of cell fractionation assays by consecutive centrifugation steps for assessment of the peripheral and tumor spheroid infiltrating immune cells is limited to tumor cell populations that generate more stable spheroids17.
Concept and approach
Our approach addresses the above-mentioned deficiencies using an &#8220;All-in-One&#8221;&#8212;3D spheroid co-culture model, which does not require the transfer of spheroids for subsequent assays. We adapted a spheroid formation device (see Table of Materials) to generate an assay for simultaneously monitoring invasive behavior of cancer cells and cytotoxicity of co-cultured T-cells. This method is user-friendly, inexpensive and allows for quick and easy handling in a relatively high-throughput 3D setting. Dependent on the type of device used, up to 81 large uniformly-sized spheroids can be generated in a single pipetting step with control over the individual spheroid size by modifying the number of cells seeded. Spheroid formation is forced by enhanced cell-cell interactions in scaffold-free agarose multi-well casts with U-shaped bottoms. We adapted this 3D system for dynamic cell-based functional studies as well as endpoint molecular and biochemical assays that include fluorescence activated cell sorting (FACS), immunofluorescence (IF) or immunohistochemistry (IHC) staining as well as gene expression analysis of the intact 3D co-culture.
For functional studies, embedding spheroids in type I collagen within the agarose casts results in invasion of cancer cells from equidistant spheroids and permits monitoring essential cell line-specific features, such as single cell vs. collective cell migration18,19. Furthermore, the collagen matrix is easily separated from the agarose cast, resulting in a 1&#8210;2 mm thick patch containing multiple spheroids, which can be further processed for IF-staining and imaging by confocal microscopy. This can reveal distinct cell invasion and cell-matrix interactions in a high-throughput screening. Also, cells in the collagen matrix can be isolated after collagen digestion and single cell dissociation for subsequent cell cultivation or analysis.
For IHC analysis of spheroids, after fixation and sectioning of the agarose cast, proteins or other molecules of interest are detectable whilst maintaining the geographic positions of the spheroids. In the approach described here, spheroids are directly embedded in Hydroxyethyl agarose processing gel within the agarose cast and the gel serves as a &#8220;lid&#8221; to retain the spheroids at the bottom of the microwells. After paraffin embedding of the agarose cast20, serial horizontal sectioning is performed with the bottom of the cast serving as the starting point.
This approach contrasts with conventional IHC sectioning of spheroids that requires harvesting of cells before embedding in Hydroxyethyl agarose processing gel21 and risks disruption of spheroids thus losing the spatial arrangement of cells. Also, cell fractionation by centrifugation for assessing whether immune cells infiltrated or remained peripheral to tumor spheroids17 is avoided by direct embedding.
Furthermore, 3D co-culture can be performed by admixing tumor, stromal or immune cells, and thus studying tumor cell crosstalk or recapitulating different tumor microenvironments for analyzing cell-cell interactions including co-cultures with endothelial cells16.
This 3D spheroid co-culture setting can be used to perform co-culture of different cell types present in the tumor microenvironment and to assess the effects of altered ECM elements. Besides type I collagen, other ECM components (e.g., matrigel, matrigel/collagen mixtures, fibronectin), can be used since tumor cell invasion is impacted by the abundance of different substrates22. Also, the microwells of the agarose cast are suitable for spheroid formation of primary cell lines and for cells with low cell-cell adhesion.

<table>
	<tbody>
		<tr>
			<td>3D Petri Dishes</td>
			<td>Microtissues Inc</td>
			<td>Z764019 &#38; Z764051</td>
			<td>referred to as &#34;rubber molds&#34; in the protocols; 81-microwell &#38; 35-microwell molds</td>
		</tr>
		<tr>
			<td>8-well Chamber Slides</td>
			<td>Lab-Tek</td>
			<td>154534</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose Type I, low EEO</td>
			<td>Sigma-Aldrich</td>
			<td>A6013</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-rabbit-HRP conjugated secondary antibody</td>
			<td>Agilent</td>
			<td>K4003</td>
			<td>ready to use</td>
		</tr>
		<tr>
			<td>Collagen Type I, Rat Tail, 100 mg</td>
			<td>Millipore</td>
			<td>08-115</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase Type 4, 1 g</td>
			<td>Worthington</td>
			<td>LS004188</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM, fetal bovine serum</td>
			<td>ThermoFisher</td>
			<td>11965092, 16000044</td>
			<td>referred to as &#34;cell culture medium&#34; in the protocols</td>
		</tr>
		<tr>
			<td>Harris hematoxylin</td>
			<td>ThermoFisher</td>
			<td>SH30-500D</td>
			<td></td>
		</tr>
		<tr>
			<td>HistoGel</td>
			<td>ThermoFisher</td>
			<td>HG-4000-012</td>
			<td>referred to as &#34;Hydroxyethyl agarose processing gel&#34; in the protocols</td>
		</tr>
		<tr>
			<td>Hoechst</td>
			<td>Life Technologies</td>
			<td>H1399</td>
			<td>1/1000 dilution</td>
		</tr>
		<tr>
			<td>Phalloidin 546</td>
			<td>Invitrogen</td>
			<td>486624</td>
			<td>1/200 dilution</td>
		</tr>
		<tr>
			<td>rabbit anti-CD8 antibody</td>
			<td>Cell Signaling</td>
			<td>98941</td>
			<td>1/25 dilution</td>
		</tr>
		<tr>
			<td>rat anti-keratin 8</td>
			<td>DSHB</td>
			<td>TROMA-I AB_531826</td>
			<td>1/500 dilution</td>
		</tr>
		<tr>
			<td>RNeasy Mini Kit</td>
			<td>Qiagen</td>
			<td>74104</td>
			<td>referred to as &#34;RNA extraction kit&#34; in the protocols</td>
		</tr>
		<tr>
			<td>RPMI</td>
			<td>ThermoFisher</td>
			<td>11875093</td>
			<td>for T-cell culture medium</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>BioRad</td>
			<td>1610407</td>
			<td>referred to as &#34;Octoxynol&#34; in the protocols</td>
		</tr>
		<tr>
			<td>Trizol</td>
			<td>ThermoFisher</td>
			<td>15596026</td>
			<td>referred to as &#34;guanidinium thiocyanate with phenol&#34; in the protocols</td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma-Aldrich</td>
			<td>P1379</td>
			<td>referred to as &#34;polysorbate 20&#34; in the protocols</td>
		</tr>
		<tr>
			<td>TypLE</td>
			<td>ThermoFisher</td>
			<td>12604013</td>
			<td>referred to as &#34;cell dissociation enzymes solution&#34; in the protocols</td>
		</tr>
	</tbody>
</table>

monitoring cancer cell invasion and t-cell cytotoxicity in 3d culture

Significant progress has been made in treating cancer with immunotherapy, although a large number of cancers remain resistant to treatment. A limited number of assays allow for direct monitoring and mechanistic insights into the interactions between tumor and immune cells, amongst which, T-cells play a significant role in executing the cytotoxic response of the adaptive immune system to cancer cells. Most assays are based on two-dimensional (2D) co-culture of cells due to the relative ease of use but with limited representation of the invasive growth phenotype, one of the hallmarks of cancer cells. Current three-dimensional (3D) co-culture systems either require special equipment or separate monitoring for invasion of co-cultured cancer cells and interacting T-cells.
Here we describe an approach to simultaneously monitor the invasive behavior in 3D of cancer cell spheroids and T-cell cytotoxicity in co-culture. Spheroid formation is driven by enhanced cell-cell interactions in scaffold-free agarose microwell casts with U-shaped bottoms. Both T-cell co-culture and cancer cell invasion into type I collagen matrix are performed within the microwells of the agarose casts without the need to transfer the cells, thus maintaining an intact 3D co-culture system throughout the assay. The collagen matrix can be separated from the agarose cast, allowing for immunofluorescence (IF) staining and for confocal imaging of cells. Also, cells can be isolated for further growth or subjected to analyses such as for gene expression or fluorescence activated cell sorting (FACS). Finally, the 3D co-culture can be analyzed by immunohistochemistry (IHC) after embedding and sectioning. Possible modifications of the assay include altered compositions of the extracellular matrix (ECM) as well as the inclusion of different stromal or immune cells with the cancer cells.

The 3D co-culture model allows for different assays shown in Figure 1A, which can be combined or modified as needed. In our established experimental setup, tumor and T-cells are co-cultured for 2 days followed by initiation of the invasion assay for selection of invasive and/or resistant tumor cells (Figure 1B). On day 4 the quantitation of invasion is performed and &#8220;survivor&#8221; cells are isolated from the collagen matrix or directly processed for RNA<...

Watch this Scientific Journal Video about Monitoring Cancer Cell Invasion and T-Cell Cytotoxicity in 3D Culture at JoVE.com

Monitoring Cancer Cell Invasion and T-Cell Cytotoxicity in 3D Culture

The presented approach simultaneously evaluates cancer cell invasion in 3D spheroid assays and T-cell cytotoxicity. Spheroids are generated in a scaffold-free agarose multi-microwell cast. Co-culture and embedding in type I collagen matrix are performed within the same device which allows to monitor cancer cell invasion and T-cell mediated cytotoxicity.

Significant progress has been made in treating cancer with immunotherapy, although a large number of cancers remain resistant to treatment. A limited ...

These methods can provide mechanistic insights into immune cell-mediated tumor cell cytotoxicity and invasive behavior in a 3D setting. The main advantage of this technique is that this 3D spheroid co-culture model does not require the transfer of spheroids for multiple subsequent essays. Demonstrating this procedure will be Apsra Nasir, a PhD student from our department.To generate the spheroids using aseptic technique in a cell culture hood add 500 microliters of molten agarose into an 81 microwell rubber mold taking care to avoid bubbles. When the agarose has solidified carefully flex the rubber mold to pop out the agarose casts into individual wells of a 12 well plate. To equilibrate the casts add 2.5 milliliters of cell culture medium supplemented with 10%fetal bovine serum into each well and place the plate into a cell culture incubator for one hour.At the end of the incubation tilt the plate to remove the cell culture medium in the surrounding first, then in the seeding chamber and carefully seed 190 microliters of the prepared to tumor cell suspension dropwise into each cell seeding chamber. After a 15 minute incubation in the cell culture incubator add at 2.5 milliliters of medium to the outside of the cast and return the plate to the incubator for 48 hours. To set up a T-cell co-culture resuspend the appropriate number of T-cells in 190 microliters of inappropriate T-cell culture, medium per well until the 12 well-plate to allow removal of the cell culture medium surrounding the agarose cast first.Then in the seeding chamber, without removing the spheroids use a light microscope to check whether any spheroids have been aspirated and holding the P200 loaded pipette about half a centimeter above each cast carefully seed the T-cells onto the casts in a dropwise fashion without dislodging the spheroids. When all of the casts have been seeded carefully returned the plate to the cell culture incubator for 15 minutes before adding fresh cell culture medium supplemented with fetal bovine serum to the outside of each cast for another 48 hour incubation. To embed the 3D co-cultures in type one collagen dilute stock collagen with serum free base medium to a final working concentration of three milligrams per milliliter and add 11 microliters of 10X PBS, add 1.2 microliters of one molar sodium hydroxide per 100 microliters of collagen.After neutralizing the collagen solution on ice for one hour, remove the cell culture medium surrounding and within each cast as demonstrated. Carefully add the neutralized collagen one mixture to each cast in a dropwise fashion, and immediately returned the plate to the cell culture incubator for five minutes before inverting the plate for an additional one hour in the incubation. At the end of the incubation place the plate right side up in the biosafety hood and slowly add a fresh cell culture medium down the side of each well.Then return the plate to the cell culture incubator for 48 hours. For immunofluorescent staining of the embedded 3D co-cultures fix each entire agarose cast including the spheroids in 5.4%formalin overnight at room temperature in a humidified chamber. The next day, remove the formalin surrounding the agarose cast and use sleek tip tweezers to grasp the corner of each collagen matrix to allow the casts to be peeled from the seeding chambers in a single fluid movement.Place each collagen patch into a single well of an eight well chamber slide and add 250 microliters of 0.5%octoxynol all to each well. After one hour at room temperature replace the octoxynol with 250 microliters of blocking solution. After one hour at room temperature add a 250 microliters of the primary antibody cocktail of interest to each well and place a slide in a dark humidified chamber overnight at room temperature.The next morning remove the primary antibody from each well and wash the wells three times with 300 microliters of IF buffer for five minutes at room temperature per wash. After the last wash, add a 250 microliters of inappropriate secondary antibody solution to each well for a one hour incubation at room temperature protected from light. At the end of the incubation remove the antibody and wash each sample three times with IF buffer as demonstrated.After the last wash rinse the samples with 300 microliters of PBS per well and carefully remove the walls of the chamber slide. So that only the glass slide at the bottom remains. Add 200 microliters of mounting medium to the glass slide and carefully drop the cover slip onto the sample without creating bubbles then store the mounted samples in a dark dry place overnight before imaging by confocal fluorescence microscopy Here typical experimental setups for the assays and they yield of representative and analyzable samples at the end of the experiment for each protocol can be observed.Embedding the 3D culture in type one collagen within the micro wells of an agarose cast allows monitoring and analysis of the invasion by image J.In this analysis of two primary murine, pancreatic cancer cell lines different spheroid shapes and invasive behaviors were observed. The first cell line one demonstrated a more compact spheroid formation and spiky invasion similar to that observed for single cell invasions. While the second cell line formed spheroids that were more loose and demonstrated a collective invasion pattern.Co-culture can be performed with two different tumor clonal cell lines seeded at the same time or with tumor and T-cells upon tumor spheroid formation or a subsequent tumor T-cell interaction evaluations. For a detailed assessment of the invasive behavior immunofluorescent staining and con focal imaging can be performed in a high throughput manner. The agarose cast allows embedding of the whole 3D culture system in paraffin for serial sectioning and immunohistochemistry staining to quantify the spatial relationship between tumor and T-cells.For example, T-cell infiltration can be identified and characterized by cell surface marker staining. This technique allows the analysis of patient samples as well as the use of stimulating and blocking drugs to probe tumor cell T-cell interactions.

monitoring-cancer-cell-invasion-and-t-cell-cytotoxicity-in-3d-culture

Research

JoVE Journal

Cancer Research

Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased understanding of the molecular events that give rise to glioblastomas, this cancer still remains highly refractory to conventional treatment. Surgical resection of high grade brain tumors is rarely complete due to the highly infiltrative nature of glioblastoma cells. Therapeutic approaches which attenuate glioblastoma cell invasion therefore is an attractive option. Our laboratory and others have shown that tumor associated macrophages and microglia (resident brain macrophages) strongly stimulate glioblastoma invasion. The protocol described in this paper is used to model glioblastoma-macrophage/microglia interaction using in vitro culture assays. This approach can greatly facilitate the development and/or discovery of drugs that disrupt the communication with the macrophages that enables this malignant behavior. We have established two robust coculture invasion assays where microglia/macrophages stimulate glioma cell invasion by 5 - 10 fold. Glioblastoma cells labelled with a fluorescent marker or constitutively expressing a fluorescent protein are plated without and with macrophages/microglia on matrix-coated polycarbonate chamber inserts or embedded in a three dimensional matrix. Cell invasion is assessed by using fluorescent microscopy to image and count only invasive cells on the underside of the filter. Using these assays, several pharmacological inhibitors (JNJ-28312141, PLX3397, Gefitinib, and Semapimod), have been identified which block macrophage/microglia stimulated glioblastoma invasion.

Understanding the malignant behavior of cancer requires creating accurate models of how tumor cells interact with components of the tumor microenvironment, such as macrophages. Here we describe two methods to study glioblastoma cell interaction with tumor associated macrophages and microglia where the effect on glioblastoma invasion is assessed.

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased ...

A Model for Perineural Invasion in Head and Neck Squamous Cell Carcinoma

Perineural invasion (PNI) is found in approximately 40% of head and neck squamous cell carcinomas (HNSCC). Despite multimodal treatment with surgery, radiation, and chemotherapy, locoregional recurrences and distant metastases occur at higher rates, and overall survival is decreased by 40% compared to HNSCC without PNI. In vitro studies of the pathways involved in HNSCC PNI have historically been challenging given the lack of a consistent, reproducible assay. Described here is the adaptation of the dorsal root ganglion (DRG) assay for the examination of PNI in HNSCC. In this model, DRG are harvested from the spinal column of a sacrificed nude mouse and placed within a semisolid matrix. Over the subsequent days, neurites are generated and grow in a radial pattern from the cell bodies of the DRG. HNSCC cell lines are then placed peripherally around the matrix and invade preferentially along the neurites toward the DRG. This method allows for rapid evaluation of multiple treatment conditions, with very high assay success rates and reproducibility.

Perineural invasion (PNI) is a common feature of head and neck squamous cell carcinoma (HNSCC), conferring lower survival rates. Its mechanisms are poorly understood. Utilizing neurites generated from murine dorsal root ganglia confined to a semisolid matrix, the pathways involved in the PNI of HNSCC cell lines can be investigated.

Perineural invasion (PNI) is found in approximately 40% of head and neck squamous cell carcinomas (HNSCC). Despite multimodal treatment with surgery, ...

Moving Upwards: A Simple and Flexible In Vitro Three-dimensional Invasion Assay Protocol

Although 3D invasion assays have been developed, the challenge remains to study cells without affecting the integrity of their microenvironment. Traditional 3D assays such as the Boyden Chamber require that cells are displaced from the original culture location and moved to a new environment. Not only does this disrupt the cellular processes that are intrinsic to the microenvironment, but it often results in a loss of cells. These problems are especially challenging when dealing with cells that are either rare, or extremely sensitive to their microenvironment. Here, we describe the development of a 3D invasion assay that avoids both concerns. In this assay, cells are plated within a small well and an ECM matrix containing a chemoattractant is laid atop the cells. This requires no cell displacement, and allows the cells to invade upwards into the matrix. In this assay, cell invasion as well as cell morphology can be assessed within the collagen gel. Using this assay, we characterize the invasive capacity of rare and sensitive cells; the hybrid cells resulting from fusion between breast cancer cells MCF7 and mesenchymal/multipotent stem/stroma cells (MSCs).

Moving Upwards: A Simple and Flexible In Vitro Three-dimensional Invasion Assay Protocol

This protocol describes an inverted vertical invasion assay that could be used to quantify the migration and invasion capabilities of cells in a three-dimensional setting while preserving the cell microenvironment. This assay is suitable for rare and/or sensitive cells.

Although 3D invasion assays have been developed, the challenge remains to study cells without affecting the integrity of their microenvironment. ...

Therapy Testing in a Spheroid-based 3D Cell Culture Model for Head and Neck Squamous Cell Carcinoma

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with or without surgery. While platinum-based chemotherapy regimens currently represent the gold standard in terms of efficacy and are given in the vast majority of cases, new chemotherapy regimens, namely immunotherapy are emerging. However, the response rates and therapy resistance mechanisms for either chemo regimen are hard to predict and remain insufficiently understood. Broad variations of chemo and radiation resistance mechanisms are known to date. This study describes the development of a standardized, high-throughput in vitro assay to assess HNSCC cell line&#39;s response to various therapy regimens, and hopefully on primary cells from individual patients as a future tool for personalized tumor therapy. The assay is designed to being integrated into the quality-controlled standard algorithm for HNSCC patients at our tertiary care center; however, this will be subject of future studies. Technical feasibility looks promising for primary cells from tumor biopsies from actual patients. Specimens are then transferred into the laboratory. Biopsies are mechanically separated followed by enzymatic digestion. Cells are then cultured in ultra-low adhesion cell culture vials that promote the reproducible, standardized and spontaneous formation of three-dimensional, spheroid-shaped cell conglomerates. Spheroids are then ready to be exposed to chemo-radiation protocols and immunotherapy protocols as needed. The final cell viability and spheroid size are indicators of therapy susceptibility and therefore could be drawn into consideration in future to assess the patients&#39; likely therapy response. This model could be a valuable, cost-efficient tool towards personalized therapy for head and neck cancer.

We describe the evolution of a spheroid-based, three-dimensional in vitro model that enables us to test the current standard of experimental therapy regimens for head and neck squamous cell carcinoma on cell lines, aiming at evaluating therapy susceptibility and resistance on primary cells from human specimens in the future.

Current treatment options for advanced and recurrent head and neck squamous cell carcinoma (HNSCC) enclose radiation and chemo-radiation approaches with ...

Live-Cell Imaging Assays to Study Glioblastoma Brain Tumor Stem Cell Migration and Invasion

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include rapid proliferation and pervasive invasion into the normal brain. Recurrence is thought to result from the presence of radio- and chemo-resistant brain tumor stem cells (BTSCs) that invade away from the initial cancerous mass and, thus, evade surgical resection. Hence, therapies that target BTSCs and their invasive abilities may improve the otherwise poor prognosis of this disease. Our group and others have successfully established and characterized BTSC cultures from GBM patient samples. These BTSC cultures demonstrate fundamental cancer stem cell properties such as clonogenic self-renewal, multi-lineage differentiation, and tumor initiation in immune-deficient mice. In order to improve on the current therapeutic approaches for GBM, a better understanding of the mechanisms of BTSC migration and invasion is necessary. In GBM, the study of migration and invasion is restricted, in part, due to the limitations of existing techniques which do not fully account for the in vitro growth characteristics of BTSCs grown as neurospheres. Here, we describe rapid and quantitative live-cell imaging assays to study both the migration and invasion properties of BTSCs. The first method described is the BTSC migration assay which measures the migration toward a chemoattractant gradient. The second method described is the BTSC invasion assay which images and quantifies a cellular invasion from neurospheres into a matrix. The assays described here are used for the quantification of BTSC migration and invasion over time and under different treatment conditions.

Here, we describe live-cell imaging techniques to quantitatively measure the migration and invasion of glioblastoma brain tumor stem cells over time and under multiple treatment conditions.

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include ...

3-D Cell Culture System for Studying Invasion and Evaluating Therapeutics in Bladder Cancer

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. While 75% of bladder cancers are non-invasive and unlikely to metastasize, about 25% progress to an invasive growth pattern. Up to half of the patients with invasive cancers will develop lethal metastatic relapse. Thus, understanding the mechanism of invasive progression in bladder cancer is crucial to predict patient outcomes and prevent lethal metastases. In this article, we present a three-dimensional cancer invasion model which allows incorporation of tumor cells and stromal components to mimic in vivo conditions occurring in the bladder tumor microenvironment. This model provides the opportunity to observe the invasive process in real time using time-lapse imaging, interrogate the molecular pathways involved using confocal immunofluorescent imaging and screen compounds with the potential to block invasion. While this protocol focuses on bladder cancer, it is likely that similar methods could be used to examine invasion and motility in other tumor types as well.

The processes governing bladder cancer invasion represent opportunities for biomarker and therapeutic development. Here we present a bladder cancer invasion model which incorporates 3-D culture of tumor spheroids, time-lapse imaging and confocal microscopy. This technique is useful for defining the features of the invasive process and for screening therapeutic agents.

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. ...

In Vitro Tumor Cell Rechallenge For Predictive Evaluation of Chimeric Antigen Receptor T Cell Antitumor Function

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and manufacturing optimizations. One challenge for these development efforts, however, has been the establishment of in vitro assays that can robustly inform selection of the optimal CAR T cell products for in vivo therapeutic success. Standard in vitro tumor-lysis assays often fail to reflect the true antitumor potential of the CAR T cells due to the relatively short co-culture time and high T cell to tumor ratio. Here, we describe an in vitro co-culture method to evaluate CAR T cell recursive killing potential at high tumor cell loads. In this assay, long-term cytotoxic function and proliferative capacity of CAR T cells is examined in vitro over 7 days with additional tumor targets administered to the co-culture every other day. This assay can be coupled with profiling T cell activation, exhaustion and memory phenotypes. Using this assay, we have successfully distinguished the functional and phenotypic differences between CD4+ and CD8+ CAR T cells against glioblastoma (GBM) cells, reflecting their differential in vivo antitumor activity in orthotopic xenograft models. This method provides a facile approach to assess CAR T cell potency and to elucidate the functional variations across different CAR T cell products.

Here, we describe an in vitro co-culture method to recursively challenge tumor-targeted T cells, which allows for phenotypic and functional analysis of antitumor T cell activity.

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and ...

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The orthotopic murine model can be performed on large cohorts of immunocompetent mice simultaneously, is relatively inexpensive and preserves the cognate tissue microenvironment. The quantification of T cell infiltration and cytotoxic activity within orthotopic tumors provides a useful indicator of an antitumoral response.
This protocol describes the methodology for surgical generation of orthotopic pancreatic tumors by injection of a low number of syngeneic tumor cells resuspended in 5 &#181;L basement membrane directly into the pancreas. Mice bearing orthotopic tumors take approximately 30 days to reach endpoint, at which point tumors can be harvested and processed for characterization of tumor-infiltrating T cell activity. Rapid enzymatic digestion using collagenase and DNase allows a single-cell suspension to be extracted from tumors. The viability and cell surface markers of immune cells extracted from the tumor are preserved; therefore, it is appropriate for multiple downstream applications, including flow-assisted cell sorting of immune cells for culture or RNA extraction, flow cytometry analysis of immune cell populations. Here, we describe the ex vivo stimulation of T cell populations for intracellular cytokine quantification (IFN&#947; and TNF&#945;) and degranulation activity (CD107a) as a measure of overall cytotoxicity. Whole-tumor digests were stimulated with phorbol myristate acetate and ionomycin for 5 h, in the presence of anti-CD107a antibody in order to upregulate cytokine production and degranulation. The addition of brefeldin A and monensin for the final 4 h was performed to block extracellular transport and maximize cytokine detection. Extra- and intra-cellular staining of cells was then performed for flow cytometry analysis, where the proportion of IFN&#947;+, TNF&#945;+ and CD107a+ CD4+ and CD8+ T cells was quantified.
This method provides a starting base to perform comprehensive analysis of the tumor microenvironment.

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

This protocol describes the surgical generation of orthotopic pancreatic tumors and the rapid digestion of freshly isolated murine pancreatic tumors. Following digestion, viable immune cell populations can be used for further downstream analysis, including ex vivo stimulation of T cells for intracellular cytokine detection by flow cytometry.

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The ...

Impedance-based Real-time Measurement of Cancer Cell Migration and Invasion

Cancer arises due to uncontrolled proliferation of cells initiated by genetic instability, mutations, and environmental and other stress factors. These acquired abnormalities in complex, multilayered molecular signaling networks induce aberrant cell proliferation and survival, extracellular matrix degradation, and metastasis to distant organs. Approximately 90% of cancer-related deaths are estimated to be caused by the direct or indirect effects of metastatic dissemination. Therefore, it is important to establish a highly reliable, comprehensive system to characterize cancer cell behaviors upon genetic and environmental manipulations. Such a system can give a clear understanding of the molecular regulation of cancer metastasis and the opportunity for successful development of stratified, precise therapeutic strategies. Hence, accurate determination of cancer cell behaviors such as migration and invasion with gain or loss of function of gene(s) allows assessment of the aggressive nature of cancer cells. The real-time measurement system based on cell impedance enables researchers to continually acquire data during a whole experiment and instantly compare and quantify the results under various experimental conditions. Unlike conventional methods, this method does not require fixation, staining, and sample processing to analyze cells that migrate or invade. This method paper emphasizes detailed procedures for real-time determination of migration and invasion of glioblastoma cancer cells.

Cancer is a lethal disease due to its ability to metastasize to different organs. Determining the ability of cancer cells to migrate and invade under various treatment conditions is crucial to assessing therapeutic strategies. This protocol presents a method to assess the real-time metastatic abilities of a glioblastoma cancer cell line.&#160;

Cancer arises due to uncontrolled proliferation of cells initiated by genetic instability, mutations, and environmental and other stress factors. These ...

Modeling Oral-Esophageal Squamous Cell Carcinoma in 3D Organoids

Esophageal squamous cell carcinoma (ESCC) is prevalent worldwide, accounting for 90% of all esophageal cancer cases each year, and is the deadliest of all human squamous cell carcinomas. Despite recent progress in defining the molecular changes accompanying ESCC initiation and development, patient prognosis remains poor. The functional annotation of these molecular changes is the necessary next step and requires models that both capture the molecular features of ESCC and can be readily and inexpensively manipulated for functional annotation. Mice treated with the tobacco smoke mimetic 4-nitroquinoline 1-oxide (4NQO) predictably form ESCC and esophageal preneoplasia. Of note, 4NQO lesions also arise in the oral cavity, most commonly in the tongue, as well as the forestomach, which all share the stratified squamous epithelium. However, these mice cannot be simply manipulated for functional hypothesis testing, as generating isogenic mouse models is time- and resource-intensive. Herein, we overcome this limitation by generating single cell-derived three-dimensional (3D) organoids from mice treated with 4NQO to characterize murine ESCC or preneoplastic cells ex vivo. These organoids capture the salient features of ESCC and esophageal preneoplasia, can be cheaply and quickly leveraged to form isogenic models, and can be utilized for syngeneic transplantation experiments. We demonstrate how to generate 3D organoids from normal, preneoplastic, and SCC murine esophageal tissue and maintain and cryopreserve these organoids. The applications of these versatile organoids are broad and include the utilization of genetically engineered mice and further characterization by flow cytometry or immunohistochemistry, the generation of isogeneic organoid lines using CRISPR technologies, and drug screening or syngeneic transplantation. We believe that the widespread adoption of the techniques demonstrated in this protocol will accelerate progress in this field to combat the severe burden of ESCC.

This protocol describes the key steps to generate and characterize murine oral-esophageal 3D organoids that represent normal, preneoplastic, and squamous cell carcinoma lesions induced via chemical carcinogenesis.

Esophageal squamous cell carcinoma (ESCC) is prevalent worldwide, accounting for 90% of all esophageal cancer cases each year, and is the deadliest of all ...