This work was funded by start-up funds provided to Dr. Silviya P Zustiak by Saint Louis University as well as by a seed grant from the Henry and Amelia Nasrallah Center for Neuroscience at Saint Louis University awarded to Dr. Silviya P Zustiak.

Fabrication Followed by 3D Encapsulation of Tumor Spheroids in PEG Hydrogels

<ol>
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S., Kim, Y., Rao, S. 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D., Tavana, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomaterials-based+approaches+to+tumor+spheroid+and+organoid+modeling.">Biomaterials-based approaches to tumor spheroid and organoid modeling.</a> Advanced Healthcare Materials. 7 (6), 1700980 (2018).</li><li>Shin, 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=Alginate-marine+collagen-agarose+composite+hydrogels+as+matrices+for+biomimetic+3D+cell+spheroid+formation.">Alginate-marine collagen-agarose composite hydrogels as matrices for biomimetic 3D cell spheroid formation.</a> RSC Advances. 6 (52), 46952-46965 (2016).</li><li>Pradhan, S., Clary, J. M., Seliktar, D., Lipke, E. 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+three-dimensional+spheroidal+cancer+model+based+on+PEG-fibrinogen+hydrogel+microspheres.">A three-dimensional spheroidal cancer model based on PEG-fibrinogen hydrogel microspheres.</a> Biomaterials. 115, 141-154 (2017).</li><li>Imaninezhad, M., Hill, L., Kolar, G., Vogt, K., Zustiak, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Templated+macroporous+polyethylene+glycol+hydrogels+for+spheroid+and+aggregate+cell+culture.">Templated macroporous polyethylene glycol hydrogels for spheroid and aggregate cell culture.</a> Bioconjugate Chemistry. 30 (1), 34-46 (2018).</li><li>Mirab, F., Kang, Y. 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The authors have nothing to disclose.

Hydrogel-based multicellular tumor spheroid models are increasingly being developed to advance cancer therapeutic discoveries11,13,29. They are beneficial because they emulate key parameters of the tumor microenvironment in a controlled manner and, despite their complexity, are simpler and cheaper to use than in vivo models, and many are compatible with high-throughput screening technologies. The hydrogel biomaterials can be tun...

Tumor spheroids have emerged as useful in vitro tools in studying cancer etiology, pathology, and drug responsiveness1. Traditionally, spheroids have been cultured in conditions such as low adhesion plates or bioreactors, where cell-cell adhesion is favored over cell-surface adhesion2. However, it is now recognized that to recapitulate the tumor microenvironment more faithfully, in vitro spheroid models should capture both cell-cell and cell-matrix interactions. This has prompted multiple groups to design scaffolds, such as hydrogels, where spheroids can be encapsulated3,4. Such hydrogel-based spheroid models enable the elucidation of cell-cell and cell-matrix interactions on various cell behaviors, such as viability, proliferation, stemness, or therapy responsiveness3.
Here, we describe a protocol for the encapsulation of glioblastoma spheroids in polyethylene glycol (PEG) hydrogels. There are multiple literature reports of glioblastoma cell spheroid encapsulation in hydrogels. For example, spheroids were formed by encapsulating U87 cells in PEG hydrogels decorated with an RGDS adhesive ligand and crosslinked with an enzymatically cleavable peptide to determine the effect of hydrogel stiffness on cell behavior5. U87 cells have also been formed in other PEG-based or hyaluronic acid-based hydrogels to expand the cancer stem cell population6 or to explore matrix-mediated mechanisms of chemotherapy resistance7,8,9. Glioblastoma spheroids have also been encapsulated in gelatin hydrogels to study the crosstalk between microglia and cancer cells and its effect on cell invasion10. Overall, such studies have demonstrated the utility of hydrogel-based in vitro models in understanding glioblastoma pathology and devising treatments.
Further, there are different methods for tumor spheroid fabrication and hydrogel encapsulation11. For example, dispersed cells could be seeded in hydrogels and allowed to form spheroids over time5,12. One drawback of such a method is the polydispersity of the formed spheroids, which could lead to differential cell responses. To produce uniform spheroids, cells could be encapsulated in microgels and cultured for extended periods until they invade and remodel the gel13, or cells could be deposited in templated gels with spherical &#39;holes&#39; and allowed to aggregate14. The drawback of these methods is their relative complexity, the need for a droplet generator or other means to form microgels or the &#39;holes&#39; in the gel, and the time it takes for spheroids to grow and mature. Alternatively, spheroids could be pre-formed in microwells9,15,16 or in hanging-drop plates17,18 and then encapsulated in a hydrogel, similar to the technique described here. These methods are simpler and can be done in a higher throughput fashion. Interestingly, it has been shown that the method of spheroid formation can affect spheroid cell behaviors, such as gene expression, cell proliferation, or drug responsiveness19,20.
Here, we focus on glioblastoma since it is a solid tumor whose native environment is the soft, nanoporous brain matrix21, which can be mimicked by a soft, nanoporous hydrogel. Glioblastoma is also the deadliest brain cancer for which there is no available cure22. However, the protocol described here can be used for the encapsulation of spheroids representing any solid tumor. We chose to use PEG hydrogels that are formed through a Michael-type addition reaction23. PEG is a synthetic, non-degradable, and biocompatible hydrogel that is inert and serves as scaffolding and physical cell support but does not support cell attachment23. Cell adhesiveness can be added separately via tethering of whole proteins or adhesive ligands24, and degradability can be added via chemical modifications of the PEG polymer chain or hydrolytically or enzymatically degradable crosslinkers25,26. This allows for biochemical properties to be tuned independently of mechanical or physical hydrogel properties, which could be advantageous in studying cell-matrix interactions. The Michael-type gelation chemistry is selective and happens at physiological conditions; hence, it allows for spheroid encapsulation by simply mixing the spheroids with the hydrogel precursor solution.
Overall, the methodology presented here has several notable characteristics. First, fabricating tumor spheroids in a multiwell assembly is efficient, quick, and the cost of the required materials is low. Second, the spheroids are produced in large batches in a variety of sizes with low polydispersity. Finally, only commercially available materials are required. The utility of the methodology is illustrated by exploring the effect of substrate properties on spheroid cell viability, circularity, and cell stemness.

<table><tbody><tr><td>70% Ethanol</td><td>Fisher Scientific&amp;nbsp;</td><td>LC22210-4</td><td></td></tr><tr><td>15 mL Conicals</td><td>FALCON</td><td>352097</td><td></td></tr><tr><td>24-Well Plate Ultra Low Attachment plates</td><td>Fisher Scientific</td><td>07-200-602</td><td></td></tr><tr><td>35 mm Petri Dish</td><td>Amazon</td><td>706011</td><td></td></tr><tr><td>4-arm poly(ethylene glycol)-acrylate (4-arm PEG-Ac; 10 kDa)</td><td>Laysan Bio</td><td>ACRL-PEG-ACRL-10K-5g</td><td></td></tr><tr><td>50 mL Conicals</td><td>Fisher Scinetific</td><td>3181345107</td><td></td></tr><tr><td>6-well AggreWell 400&amp;nbsp;</td><td>StemCell Technologies, Vancouver, Canada</td><td>34421</td><td>Square pyramidal microwells&amp;nbsp;</td></tr><tr><td>anti-adherence rinsing solution</td><td>StemCell Technologies, Vancouver, Canada</td><td>Cat #: 07010</td><td></td></tr><tr><td>Aspartic Acid-Arginine-Cysteine-Glycine-Valine-Proline-Methionine-Serine-Methionine-Arginine-Glycine-Cysteine-Arginine- Aspartic Acid (DRCG-VPMSMR-GCRD) peptide</td><td>Genic Bio, Shanghai, China</td><td>n/a</td><td>Custom synthesis</td></tr><tr><td>Chemical Fume Hood</td><td>KEWAUNEE</td><td>99151</td><td></td></tr><tr><td>Corning Matrigel Basement Membrane Matrix, LDEV Free&amp;nbsp;</td><td>Corning</td><td>356234</td><td>Basement membrane matrix</td></tr><tr><td>Detergent - Triton-X</td><td>Sigma Aldrich</td><td>T8787</td><td>Nonionic surfactant</td></tr><tr><td>Dimethyl sulfoxide (DMSO)</td><td>Fisher Scientific&amp;nbsp;</td><td>BP231-100</td><td></td></tr><tr><td>Disposable Pipettes (1 mL, 2 mL, 5 mL, 10 mL, 25 mL, 50 mL)</td><td>Fisher Scinetific</td><td>1 mL: 13-678-11B, 2mL: 05214038, 5mL(FALCON): 357529, 10mL: 13-678-11E, 25mL: 13-678-11, 50mL: 13-678-11F</td><td></td></tr><tr><td>Fetal Bovine Serum</td><td>HyClone</td><td>SH30073-03</td><td></td></tr><tr><td>Formaldehyde 37% Solution</td><td>Sigma Aldrich</td><td>F1635</td><td></td></tr><tr><td>Glass Plates</td><td>Slumpys</td><td>GBS4100SFSL</td><td></td></tr><tr><td>Glass Transfer Pipettes</td><td>Fisher Scinetific</td><td>5 3/4&quot;: 1367820A, 9&quot;:136786B</td><td></td></tr><tr><td>Glycine-Arginine-Cysteine-Aspartic Acid-Arginine-Glycine-Aspartic Acid-Serine (GRCD-RGDS) peptide</td><td>Genic Bio, Shanghai, China</td><td>n/a</td><td>Custom synthesis</td></tr><tr><td>Hemacytometer</td><td>Bright-Line</td><td>383684</td><td></td></tr><tr><td>Hydrophobic solution - Repel Silane&amp;nbsp;</td><td>GE Healthcare Bio-Sciences</td><td>17-1332-01</td><td></td></tr><tr><td>Incubator</td><td>NUAIRE</td><td>NU-8500</td><td></td></tr><tr><td>Inverted Microscope (Axiovert 25)</td><td>Zeiss</td><td>663526</td><td></td></tr><tr><td>Invitrogen DiOC16(3) (3,3&#039;-Dihexadecyloxacarbocyanine Perchlorate)</td><td>Fisher Scientific&amp;nbsp;</td><td>D1125</td><td></td></tr><tr><td>Leica Confocal SP8</td><td>Leica Microsystems Inc.</td><td></td><td></td></tr><tr><td>Light and Flourescent Microscope (Axiovert 200M)</td><td>Zeiss</td><td>3820005619</td><td></td></tr><tr><td>Micro centrifuge tubes</td><td>Fisher Scientific</td><td>2 mL: 02681258</td><td></td></tr><tr><td>Microscope Software</td><td>Zeiss</td><td>AxioVision Rel. 4.8.2</td><td></td></tr><tr><td>Nestin Alexa Fluor 594&amp;nbsp;</td><td>Santa Cruz Biotechnology</td><td>sc-23927</td><td></td></tr><tr><td>Parafilm</td><td>PARAFILM&amp;nbsp;</td><td>PM992</td><td></td></tr><tr><td>PBS (1x), pH 7.4</td><td>HyClone</td><td>SH30256.01</td><td></td></tr><tr><td>Penicillin Streptomycin</td><td>MP Biomedicals</td><td>1670046</td><td></td></tr><tr><td>Pipette Aid</td><td>Drummond Scientific Co.</td><td>P-76864</td><td></td></tr><tr><td>Pipette Tips (1&amp;ndash;200 &amp;micro;L, 101&amp;ndash;1000 &amp;micro;L)</td><td>Fisher Scinetific</td><td>2707509</td><td></td></tr><tr><td>Plastic Standard Disposable Transfer Pipettes</td><td>Fisher Scientific</td><td>13-711-9D</td><td></td></tr><tr><td>Plastic Weigh Boats (100 mL)</td><td>Amazon&amp;nbsp;</td><td>mdo-azoc-1030</td><td></td></tr><tr><td>poly(ethylene glycol)-dithiol (PEG-diSH; 3.4 kDa)</td><td>Laysan Bio</td><td>SH-PEG-SH-3400-5g</td><td></td></tr><tr><td>Polydimehylsiloxane (PDMS) [Slygard 182 Elastomer Kit]</td><td>Elsworth Adhesives</td><td>3097358-1004</td><td>Polydimethylsiloxane</td></tr><tr><td>Powder Free Examination Gloves</td><td>Quest</td><td>92897</td><td></td></tr><tr><td>Propidium iodide, 1 mg/mL aqueous soln.&amp;nbsp;</td><td>Fisher Scientific&amp;nbsp;</td><td>AAJ66584AB</td><td></td></tr><tr><td>RPMI-1640 Medium (1x)</td><td>HyClone</td><td>SH30027-02</td><td></td></tr><tr><td>Silicone spacers - Silicone sheet, 0.5 mm thick/13 cm x 18 cm</td><td>Grace Bio-Labs</td><td>JTR-S-0.5</td><td></td></tr><tr><td>SOX2 Alexa Fluor 488&amp;nbsp;</td><td>Santa Cruz Biotechnology</td><td>sc-365823</td><td></td></tr><tr><td>Tissue Culture Hood</td><td>NUAIRE</td><td>NU-425-600</td><td></td></tr><tr><td>Triethanolamine, &amp;ge;99.0% (GC)&amp;nbsp;</td><td>Sigma Aldrich</td><td>90279</td><td></td></tr><tr><td>U-87 MG human glioblastoma cells</td><td>American Type Culture Collection&amp;nbsp;</td><td>HTB-14</td><td></td></tr></tbody></table>

tumor spheroid fabrication and encapsulation in polyethylene glycol hydrogels for studying spheroid-matrix interactions

Three-dimensional (3D) encapsulation of spheroids is crucial to adequately replicate the tumor microenvironment for optimal cell growth. Here, we designed an in vitro 3D glioblastoma model for spheroid encapsulation to mimic the tumor extracellular microenvironment. First, we formed square pyramidal microwell molds using polydimethylsiloxane. These microwell molds were then used to fabricate tumor spheroids with tightly controlled sizes from 50-500 &#956;m. Once spheroids were formed, they were harvested and encapsulated in polyethylene glycol (PEG)-based hydrogels. PEG hydrogels are a versatile platform for spheroid encapsulation, as hydrogel properties such as stiffness, degradability, and cell adhesiveness can be tuned independently. Here, we used a representative soft (~8 kPa) hydrogel to encapsulate glioblastoma spheroids. Finally, a method to stain and image spheroids was developed to obtain high-quality images via confocal microscopy. Due to the dense spheroid core and relatively sparse periphery, imaging can be difficult, but using a clearing solution and confocal optical sectioning helps alleviate these imaging difficulties. In summary, we show a method to fabricate uniform spheroids, encapsulate them in PEG hydrogels and perform confocal microscopy on the encapsulated spheroids to study spheroid growth and various cell-matrix interactions.

Spheroid-based drug screening platforms to study chemotherapeutic effects are increasingly sought after due to the emphasis on modulating the tumor microenvironment upon spheroid encapsulation in biomaterials replicating native tissue. Here we developed a method for multicellular tumor spheroid preparation and subsequent encapsulation and imaging in a 3D hydrogel. The spheroids are prepared in microwell molds (Figure 3A,B), which result in spheroids with spherical shapes and...

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Author Spotlight: In Vitro Hydrogel Model for Glioblastoma Microenvironment Study

Here, we present a protocol that enables fast, robust, and cheap fabrication of tumor spheroids followed by hydrogel encapsulation. It is widely applicable as it does not require specialized equipment. It would be particularly useful for exploring spheroid-matrix interactions and building in vitro tissue physiology or pathology models.

Tumor Spheroid Fabrication and Encapsulation in Polyethylene Glycol Hydrogels for Studying Spheroid-Matrix Interactions

Three-dimensional (3D) encapsulation of spheroids is crucial to adequately replicate the tumor microenvironment for optimal cell growth.  Here, we ...

tumor-spheroid-fabrication-encapsulation-polyethylene-glycol

Research

JoVE Journal

Bioengineering

1.3K Views.  Saint Louis University. Ons laboratorium richt zich op het ontwerpen van in vitro hydrogelmodellen voor inkapseling van glioblastoomsteroïden om de extracellulaire micro-omgeving van de tumor na te bootsen. De effectieve substraat-, mechanische en biochemische eigenschappen op de levensvatbaarheid, circulariteit, stamheid en verspreiding van steroïdecellen worden met dergelijke modellen onderzocht. De huidige experimentele uitdagingen bij de ontwikkeling van tumormodules draaien om een verlangen naar complexiteit ...

Video: Auteur in de schijnwerpers: in vitro hydrogelmodel voor onderzoek naar glioblastoom micro-omgeving

Production of Large Numbers of Size-controlled Tumor Spheroids Using Microwell Plates

Tumor spheroids are increasingly recognized as an important in vitro model for the behavior of tumor cells in three dimensions. More physiologically relevant than conventional adherent-sheet cultures, they more accurately recapitulate the complexity and interactions present in real tumors. In order to harness this model to better assess tumor biology, or the efficacy of novel therapeutic agents, it is necessary to be able to generate spheroids reproducibly, in a controlled manner and in significant numbers.
The AggreWell system consists of a high-density array of pyramid-shaped microwells, into which a suspension of single cells is centrifuged. The numbers of cells clustering at the bottom of each microwell, and the number and ratio of distinct cell types involved depend only on the properties of the suspension introduced by the experimenter. Thus, we are able to generate tumor spheroids of arbitrary size and composition without needing to modify the underlying platform technology. The hundreds of microwells per square centimeter of culture surface area in turn ensure that extremely high production levels may be attained via a straightforward, nonlabor-intensive process. We therefore expect that this protocol will be broadly useful to researchers in the tumor spheroid field.

We introduce a protocol for the generation of large numbers (thousands to hundreds of thousands) of uniform size- and composition-controlled tumor spheroids, using commercially available microwell plates.

Tumor spheroids are increasingly recognized as an important in vitro model for the behavior of tumor cells in three dimensions. More physiologically ...

Fully Human Tumor-based Matrix in Three-dimensional Spheroid Invasion Assay

Two-dimensional cell culture-based assays are commonly used in in vitro cancer research. However, they lack several basic elements that form the tumor microenvironment. To obtain more reliable in vitro results, several three-dimensional (3D) cell culture assays have been introduced. These assays allow cancer cells to interact with the extracellular matrix. This interaction affects cell behavior, such as proliferation and invasion, as well as cell morphology. Additionally, this interaction could induce or suppress the expression of several pro- and anti-tumorigenic molecules. Spheroid invasion assay was developed to provide a suitable 3D in vitro method to study cancer cell invasion. Currently, animal-derived matrices, such as mouse sarcoma-derived matrix (MSDM) and rat tail type I collagen, are mainly used in the spheroid invasion assays. Taking into consideration the differences between the human tumor microenvironment and animal-derived matrices, a human myoma-derived matrix (HMDM) was developed from benign uterus leiomyoma tissue. It has been shown that HMDM induces migration and invasion of carcinoma cells better than MSDM. This protocol provided a simple, reproducible, and reliable 3D human tumor-based spheroid invasion assay using the HMDM/fibrin matrix. It also includes detailed instructions on imaging and analysis. The spheroids grow in a U-shaped ultra-low attachment plate within the HMDM/fibrin matrix and invade through it. The invasion is daily imaged, measured, and analyzed using ilastik and Fiji ImageJ software. The assay platform was demonstrated using human laryngeal primary and metastatic squamous cell carcinoma cell lines. However, the protocol is suitable also for other solid cancer cell lines.

Tumor microenvironment is an essential part of cancer growth and invasion. To mimic carcinoma progression, a biologically relevant human matrix is needed. This protocol introduces an improvement for the in vitro three-dimensional spheroid invasion assay by applying a human leiomyoma-based matrix. The protocol also introduces a computer-based cell invasion analysis.

Two-dimensional cell culture-based assays are commonly used in in vitro cancer research. However, they lack several basic elements that form the tumor ...

Cancer Research

Longitudinal Measurement of Extracellular Matrix Rigidity in 3D Tumor Models Using Particle-tracking Microrheology

The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(&#969;). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic screening assays or molecular imaging to gain new insights into impact of treatments or biochemical stimuli on the mechanical microenvironment.

Particle-tracking microrheology can be used to non-destructively quantify and spatially map changes in extracellular matrix mechanical properties in 3D tumor models.

The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and ...

A 3D Spheroid Model for Glioblastoma

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were developed. These models may be particularly important in the field of neuro-oncology. Indeed, brain tumors have the tendency to invade the healthy brain environment. We describe herein an ideal 3D glioblastoma spheroid-based assay that we developed to study tumor invasion. We provide all technical details and analytical tools to successfully perform this assay.

Here, we describe an easy-to-use invasion assay for glioblastoma. This assay is suitable for glioblastoma stem-like cells. A Fiji macro for easy quantification of invasion, migration, and proliferation is also described.

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were ...

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 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 ...

A Three-Dimensional Spheroid Model to Investigate the Tumor-Stromal Interaction in Hepatocellular Carcinoma

The aggressiveness and lack of well-tolerated and widely effective treatments for advanced hepatocellular carcinoma (HCC), the predominant form of liver cancer, rationalize its rank as the second most common cause of cancer-related death. Preclinical models need to be adapted to recapitulate the human conditions to select the best therapeutic candidates for clinical development and aid the delivery of personalized medicine. Three-dimensional (3D) cellular spheroid models show promise as an emerging in vitro alternative to two-dimensional (2D) monolayer cultures. Here, we describe a 3D tumor spheroid&#160;model which exploits the ability of individual cells to aggregate when maintained in hanging droplets, and is more representative of an in vivo environment than standard monolayers. Furthermore, 3D spheroids can be produced by combining homotypic or heterotypic cells, more reflective of the cellular heterogeneity in vivo, potentially enabling the study of environmental interactions that can influence progression and treatment responses. The current research optimized the cell density to form 3D homotypic and heterotypic tumor spheroids by immobilizing cell suspensions on the lids of standard 10 cm3 Petri dishes. Longitudinal analysis was performed to generate growth curves for homotypic versus heterotypic tumor/fibroblasts spheroids. Finally, the proliferative impact of fibroblasts (COS7 cells) and liver myofibroblasts (LX2) on homotypic tumor (Hep3B) spheroids was investigated. A seeding density of 3,000 cells (in 20 &#181;L media) successfully yielded Huh7/COS7 heterotypic spheroids, which displayed a steady increase in size up to culture day 8, followed by growth retardation. This finding was corroborated using Hep3B homotypic spheroids cultured in LX2 (human hepatic stellate cell line) conditioned medium (CM). LX2 CM triggered the proliferation of Hep3B spheroids compared to control tumor spheroids. In conclusion, this protocol has shown that 3D tumor spheroids can be used as a simple, economical, and prescreen in vitro tool to study tumor-stromal interactions more comprehensively.

Comprehensive in vitro models that faithfully recapitulate the relevant human disease are lacking. The current study presents three-dimensional (3D) tumor spheroid creation and culture, a reliable in vitro tool to study the tumor-stromal interaction in human hepatocellular carcinoma.

The aggressiveness and lack of well-tolerated and widely effective treatments for advanced hepatocellular carcinoma (HCC), the predominant form of liver ...

Generation of 3D Tumor Spheroids for Drug Evaluation Studies

In recent decades, in addition to monolayer-cultured cells, three-dimensional tumor spheroids have been developed as a potentially powerful tool for the evaluation of anticancer drugs. However, the conventional culture methods lack the ability to manipulate the tumor spheroids in a homogeneous manner at the three-dimensional level. To address this limitation, in this paper, we present a convenient and effective method of constructing average-sized tumor spheroids. Additionally, we describe a method of image-based analysis using artificial intelligence-based analysis software that can scan the whole plate and obtain data on three-dimensional spheroids. Several parameters were studied. By using a standard method of tumor spheroid construction and a high-throughput imaging and analysis system, the effectiveness and accuracy of drug tests performed on three-dimensional spheroids can be dramatically increased.

This article demonstrates a standardized method for constructing three-dimensional tumor spheroids. A strategy for spheroid observation and image-based deep-learning analysis using an automated imaging system is also described.

In recent decades, in addition to monolayer-cultured cells, three-dimensional tumor spheroids have been developed as a potentially powerful tool for the ...

Three-Dimensional (3D) Tumor Spheroid Invasion Assay

Invasion of surrounding normal tissues is generally considered to be a key hallmark of malignant (as opposed to benign) tumors. For some cancers in particular (e.g., brain tumors such as glioblastoma multiforme and squamous cell carcinoma of the head and neck &#8211; SCCHN) it is a cause of severe morbidity and can be life-threatening even in the absence of distant metastases. In addition, cancers which have relapsed following treatment unfortunately often present with a more aggressive phenotype. Therefore, there is an opportunity to target the process of invasion to provide novel therapies that could be complementary to standard anti-proliferative agents. Until now, this strategy has been hampered by the lack of robust, reproducible assays suitable for a detailed analysis of invasion and for drug screening. Here we provide a simple micro-plate method (based on uniform, self-assembling 3D tumor spheroids) which has great potential for such studies. We exemplify the assay platform using a human glioblastoma cell line and also an SCCHN model where the development of resistance against targeted epidermal growth factor receptor (EGFR) inhibitors is associated with enhanced matrix-invasive potential. We also provide two alternative methods of semi-automated quantification: one using an imaging cytometer and a second which simply requires standard microscopy and image capture with digital image analysis.

Three-Dimensional 3D Tumor Spheroid Invasion Assay

Invasion of surrounding normal tissues is a defining characteristic of malignant tumors. We provide here a simple, semi-automated micro-plate assay of invasion into a natural 3D biomatrix that has been exemplified with a number of models of advanced human cancers.

Invasion of surrounding normal tissues is generally considered to be a key hallmark of malignant (as opposed to benign) tumors. For some cancers in ...

Medicine

An Efficient and Flexible Cell Aggregation Method for 3D Spheroid Production

Monolayer cell culture does not adequately model the in vivo behavior of tissues, which involves complex cell-cell and cell-matrix interactions. Three-dimensional (3D) cell culture techniques are a recent innovation developed to address the shortcomings of adherent cell culture. While several techniques for generating tissue analogues in vitro have been developed, these methods are frequently complex, expensive to establish, require specialized equipment, and are generally limited by compatibility with only certain cell types. Here, we describe a rapid and flexible protocol for aggregating cells into multicellular 3D spheroids of consistent size that is compatible with growth of a variety of tumor and normal cell lines. We utilize varying concentrations of serum and methyl cellulose (MC) to promote anchorage-independent spheroid generation and prevent the formation of cell monolayers in a highly reproducible manner. Optimal conditions for individual cell lines can be achieved by adjusting MC or serum concentrations in the spheroid formation medium. The 3D spheroids generated can be collected for use in a wide range of applications, including cell signaling or gene expression studies, candidate drug screening, or in the study of cellular processes such as tumor cell invasion and migration. The protocol is also readily adapted to generate clonal spheroids from single cells, and can be adapted to assess anchorage-independent growth and anoikis-resistance. Overall, our protocol provides an easily modifiable method for generating and utilizing 3D cell spheroids in order to recapitulate the 3D microenvironment of tissues and model the in vivo growth of normal and tumor cells.

Here, we describe a rapid and flexible protocol for the formation of 3D cell spheroids through cell aggregation. This is easily adapted to multiple cell types and is suitable for use in a variety of applications including cell migration, invasion, or anoikis assays, and for imaging and quantifying cell-matrix interactions.

Monolayer cell culture does not adequately model the in vivo behavior of tissues, which involves complex cell-cell and cell-matrix interactions. ...

Biology

Culturing, Freezing, Processing, and Imaging of Entire Organoids and Spheroids While Still in a Hydrogel

Organoids and spheroids, three-dimensional growing structures in cell culture labs, are becoming increasingly recognized as superior models compared to two-dimensional culture models, since they mimic the human body better and have advantages over animal studies. However, these studies commonly face problems with reproducibility and consistency. During the long experimental processes - with transfers of organoids and spheroids between different cell culture vessels, pipetting, and centrifuging - these susceptible and fragile 3D growing structures are often damaged or lost. Ultimately, the results are significantly affected, since the 3D structures cannot maintain the same characteristics and quality. The methods described here minimize these stressful steps and ensure a safe and consistent environment for organoids and spheroids throughout the processing sequence while they are still in a hydrogel in a multipurpose device. The researchers can grow, freeze, thaw, process, stain, label, and then examine the structure of organoids or spheroids under various high-tech instruments, from confocal to electron microscopes, using a single multipurpose device. This technology improves the studies&#39; reproducibility, reliability, and validity, while maintaining a stable and protective environment for the 3D growing structures during processing. In addition, eliminating stressful steps minimizes handling errors, reduces time taken, and decreases the risk of contamination.

The present study describes methodologies for culturing, freezing, thawing, processing, staining, labeling, and examining entire spheroids and organoids under various microscopes, while they remain intact in a hydrogel within a multipurpose device.

Organoids and spheroids, three-dimensional growing structures in cell culture labs, are becoming increasingly recognized as superior models compared to ...

Tumor Spheroid Fabrication and Encapsulation in Polyethylene Glycol Hydrogels for Studying Spheroid-Matrix Interactions

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