Name: assessment of mitochondrial health in cancer-associated fibroblasts isolated from 3d multicellular lung tumor spheroids
Uploaded: 2022-10-21T13:00:00
Description: Watch this Scientific Journal Video about Assessment of Mitochondrial Health in Cancer-Associated Fibroblasts Isolated from 3D Multicellular Lung Tumor Spheroids at JoVE.com

This work was supported by the SERB-Women Excellence Award Project, India (SB/WEA-02/2017) and the SERB-Early Career Research Award Project, India (ECR/2017/000892) to DP. The authors, LA and SR acknowledge IIT Ropar and MHRD for their research fellowships. MK acknowledges ICMR for her research fellowship.

1. Cell culture
<ol>
	<li>Culture human lung adenocarcinoma cell line A549, and human monocytic cell line THP-1 in RPMI1640 media supplemented with 10% FBS and 1% penicillin-streptomycin at 37 &#176;C in a humidified chamber with 5% CO2.</li>
	<li>Culture MRC-5 human lung fibroblast cells in DMEM medium supplemented with 10% FBS and 1% penicillin-streptomycin solution at 37 &#176;C in a humidified chamber with 5% CO2.</li>
</ol>
2. Preparation of mult...

<ol>
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The present study introduces the development of multicellular tumor spheroids comprising tumor cells, stromal cell population (i.e., fibroblasts), and immune cell population (i.e., monocytes) using a modified hanging drop method. Fibroblasts and monocytes/macrophages are among the most significant populations that constitute the tumor microenvironment (TME), and their presence is often linked with poor patient prognosis16. When present in the TME, fibroblasts transform, exhibiting a specific cance...

Solid tumors are composed of heterogeneous cell populations which are guided by the tumor microenvironment (TME), however, the origin of most of the cells has yet to be discovered. Mainly stromal and immune cells (fibroblasts, endothelial cells, monocytes, macrophages, dendritic cells, B cells, T cells, and their subsets) reflect the tumor heterogeneity in lung, breast, renal, and other solid cancers1,2,3. Understanding the origin of each subtype and their trans-differentiation potential is of utmost need for developing advanced therapies against these cancers. The analysis of this diverse cell population in human biopsies presents itself with several challenges because of the tumor type, site, stage, limitation of sample amount, and patient-specific variabilities4. Thus, an experimental model is needed, which is not only reliable but can also simulate the in vivo tumor condition, proving itself to be ideal for studying tumor-stroma crosstalk and its involvement in disease pathophysiology.
Three-dimensional (3D) multicellular tumor spheroid (MCTS) cultures are an advantageous in vitro model system of tumors due to their resemblance to natural counterparts. MCTS can better replicate aspects of solid tumors than 2D cell culture models, including their spatial architecture, physiological responses, the release of soluble mediators, gene expression patterns, and drug resistance mechanisms. Moreover, one main advantage of MCTS is that it can be used to study tumor heterogeneity and the tumor microenvironment (TME). The hanging-drop method is the most commonly employed tool for developing and analyzing MCTS5. In this method, the different cells with media are suspended in the form of droplets, which allows its growth in a coherent 3D aggregate fashion and is simple to access for examination. The technique is straightforward; it doesn&#39;t require many cells and eliminates the requirement of a specialized substrate like agarose for spheroid development6. An additional advantage of this method lies in the reproducibility of its technique. Furthermore, this method has also been used to co-culture mixed cell populations, such as endothelial cells and tumor cells, to simulate early tumor angiogenesis7.
In this study, multicellular 3D lung tumor spheroids were prepared with lung adenocarcinoma cells, fibroblasts, and monocytes using the hanging drop method which mimics the lung tumor microenvironment. Then the cancer-associated fibroblast (CAF) population was isolated to investigate mitochondrial health. The main idea behind developing these spheroids is to isolate the CAFs as the crosstalk among the cells in spheroids could transform the fibroblasts into a myo-fibroblast-like activated CAF state. Secondly, this study may also depict how aberrant ROS production and mitochondrial dysfunction drives the normal fibroblasts toward the more aggressive CAF phenotype. It was found that fibroblasts assembled within tumor spheroids gained myofibroblastic characteristics with increased ROS activity and the induction of metabolic gene expression. This protocol highlights the importance of the tumor microenvironment in activating CAF and could be an excellent model for in vitro generation and study of CAF phenotypic characteristics.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Antibodies</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>APC anti-human &#945;-SMA</td>
			<td>R&#38;D systems</td>
			<td>Cat# IC1420A</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-fibroblast microbeads</td>
			<td>Miltenyi Biotec</td>
			<td>Cat# 130-050-601</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell lines</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>A549 lung adenocarcinoma cells</td>
			<td>NCCS Pune</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>MRC-5 fetal lung fibroblasts</td>
			<td>ATCC</td>
			<td>CCL-171</td>
			<td></td>
		</tr>
		<tr>
			<td>THP-1 Human monocytes</td>
			<td>NCCS Pune</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Chemicals</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Himedia</td>
			<td>Cat# 9048-46-8</td>
			<td></td>
		</tr>
		<tr>
			<td>2,6-dichloroindophenol (DCPIP)</td>
			<td>SRL</td>
			<td>Cat# 55287</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcein-AM</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# C3099</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# D1306</td>
			<td></td>
		</tr>
		<tr>
			<td>DCFDA</td>
			<td>Sigma</td>
			<td>Cat# D6883</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Gibco</td>
			<td>Cat# 11995073</td>
			<td></td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>Gibco</td>
			<td>Cat# 14190-144</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Thermo fisher scientific</td>
			<td>Cat# 17892</td>
			<td></td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>SRL</td>
			<td>Cat# 62858</td>
			<td></td>
		</tr>
		<tr>
			<td>EZcoun Lactate Dehydrogenase Cell Assay Kit</td>
			<td>HiMedia</td>
			<td>Cat# CCK036</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gibco</td>
			<td>Cat# 10082147</td>
			<td></td>
		</tr>
		<tr>
			<td>Halt Protease and Phosphatase Inhibitor Cocktail (100X)</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 87786</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 15630080</td>
			<td></td>
		</tr>
		<tr>
			<td>Horse heart Cytochrome c</td>
			<td>SRL</td>
			<td>Cat# 81551</td>
			<td></td>
		</tr>
		<tr>
			<td>Image-iT Red hypoxia reagent</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# H10498</td>
			<td></td>
		</tr>
		<tr>
			<td>JC-1 Dye</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# T3168</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Merck</td>
			<td>Cat# P9541</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Merck</td>
			<td>Cat# M8266</td>
			<td></td>
		</tr>
		<tr>
			<td>MOPS</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 69824</td>
			<td></td>
		</tr>
		<tr>
			<td>Nacl</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# S9888</td>
			<td></td>
		</tr>
		<tr>
			<td>NADH MB Grade</td>
			<td>SRL</td>
			<td>Cat# 54941</td>
			<td></td>
		</tr>
		<tr>
			<td>NP-40</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 85124</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Gibco</td>
			<td>Cat# 15140122</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenazine methosulfate (PMS)</td>
			<td>SRL</td>
			<td>Cat# 55782</td>
			<td></td>
		</tr>
		<tr>
			<td>Propidium iodide</td>
			<td>Thermo fisher scientific</td>
			<td>Cat# P1304MP</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Gibco</td>
			<td>Cat# 11875093</td>
			<td></td>
		</tr>
		<tr>
			<td>Single Cell Lysis Kit</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 4458235</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium ascorbate</td>
			<td>Merck</td>
			<td>Cat# A7631</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium cyanide</td>
			<td>Sigma</td>
			<td>Cat# 205222</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Deoxycholate</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 89904</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dodecyl sulphate</td>
			<td>Sigma-Aldrich</td>
			<td>Cat# L3771</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium succinate hexahydrate</td>
			<td>SRL</td>
			<td>Cat# 36313</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma</td>
			<td>Cat# S0389</td>
			<td></td>
		</tr>
		<tr>
			<td>SuperScript VILO cDNA synthesis kit</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# 11754-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>Cat# T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin 0.25% EDTA</td>
			<td>Gibco</td>
			<td>Cat# 25200072</td>
			<td></td>
		</tr>
		<tr>
			<td>Universal SYBR Green Supermix</td>
			<td>BIO-RAD</td>
			<td>Cat# 172-5124</td>
			<td></td>
		</tr>
		<tr>
			<td>Plasticware</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MACS LS Columns</td>
			<td>Miltenyi Biotec</td>
			<td>Cat# 130-042-401</td>
			<td></td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Countess II FL Automated Cell Counter</td>
			<td>Thermo Fisher Scientific</td>
			<td>Cat# AMQAF1000</td>
			<td></td>
		</tr>
		<tr>
			<td>EVOS XL core imaging system</td>
			<td>Thermo Fisher Scientific</td>
			<td>Serial Number F0518-1727-0191</td>
			<td></td>
		</tr>
		<tr>
			<td>LAS X software</td>
			<td>Leica Microsystems</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Leica fluorescent inverted microscope</td>
			<td>s</td>
			<td>DMi8 automated S/N 424150)</td>
			<td></td>
		</tr>
		<tr>
			<td>Midi MACS separator</td>
			<td>Miltenyi Biotec</td>
			<td>Cat# 130-042-302</td>
			<td></td>
		</tr>
	</tbody>
</table>

assessment of mitochondrial health in cancer-associated fibroblasts isolated from 3d multicellular lung tumor spheroids

Cancer-associated fibroblasts (CAFs) are among the most abundant stromal cells present in the tumor microenvironment, facilitating tumor growth and progression. Complexity within the tumor microenvironment, including tumor secretome, low-grade inflammation, hypoxia, and redox imbalance, fosters heterotypic interaction and allows the transformation of inactive resident fibroblasts to become active CAFs. CAFs are metabolically distinguished from normal fibroblasts (NFs) as they are more glycolytically active, produce higher levels of reactive oxygen species (ROS), and overexpress lactate exporter MCT-4, leading to the opening of the mitochondrial permeability transition pore (MPTP). Here a method has been described to analyze the mitochondrial health of activated CAFs isolated from the multicellular 3D tumor spheroids comprising of human lung adenocarcinoma cells (A549), human monocytes (THP-1), and human lung fibroblast cells (MRC5). Tumor spheroids were disintegrated at different time intervals and through magnetic-activated cell sorting, CAFs were isolated. The mitochondrial membrane potential of CAFs was assessed using JC-1 dye, ROS production by 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) staining, and enzyme activity in the isolated CAFs. Analyzing the mitochondrial health of isolated CAFs provides a better understanding of the reverse Warburg effect and can also be applied to study the consequences of CAF mitochondrial changes, such as metabolic fluxes and the corresponding regulatory mechanisms on lung cancer heterogeneity. Thus, the present study advocates an understanding of tumor-stroma interactions on mitochondrial health. It would provide a platform to check mitochondrial-specific drug candidates for their efficacies against CAFs as potential therapeutics in the tumor microenvironment, thereby preventing CAF involvement in lung cancer progression.

Figure 1 shows the development of multicellular tumor spheroids using three different cell populations-A549 (lung adenocarcinoma), MRC-5 (fibroblasts), and THP-1 (monocytes)-by the hanging drop method as observed on day 7 and day 10 under the microscope. On day 7, spheroids were compact and rigid with a 260 &#177; 5.3 &#181;m diameter, and on day 10, spheroids were 480 &#177; 7.5 &#181;m in diameter&#160;(Figure 1A upper panel, Figur...

Watch this Scientific Journal Video about Assessment of Mitochondrial Health in Cancer-Associated Fibroblasts Isolated from 3D Multicellular Lung Tumor Spheroids at JoVE.com

Assessment of Mitochondrial Health in Cancer-Associated Fibroblasts Isolated from 3D Multicellular Lung Tumor Spheroids

Multicellular 3D tumor spheroids were prepared with lung adenocarcinoma cells, fibroblasts, and monocytes, followed by the isolation of cancer-associated fibroblasts (CAFs) from these spheroids. Isolated CAFs were compared with normal fibroblasts to assess mitochondrial health by studying the mitochondrial transmembrane potential, reactive oxygen species, and enzymatic activities.

Cancer-associated fibroblasts (CAFs) are among the most abundant stromal cells present in the tumor microenvironment, facilitating tumor growth and ...

This protocol highlights the importance of the tumor microenvironment in activating the cancer-associated fibroblasts or CAF. It could be excellent in vitro model to study phenotypic characteristics. The major constraints in CAF biology lies in the limited availability of CAF from primary tumor biopsy samples.So this technique can be used to study various aspects of CAF biology. This study depicts aberrant cross production and mitochondrial dysfunction associated with CAF activation leading to a poor tumor prognosis. The application of this method would be useful for assessing the tumor's trauma interactions particularly CAF activation and mitochondrial health.In order to explore the novel drug targets. Individuals must have experience in cell procedure before performing this technique. The visual demonstration of this technique will allow understanding the critical steps in isolating the CAF population from the tumor spheroids and downstream applications to study CAF biology.Miss Leena Arora, Miss Moyna Kalia, and Mrs. Soumyajit Roy, assistants of my lab perform the experiments. To begin grow human lung adenocarcinoma A549 and human lung fibroblast MRC-5 adherent cells in DMEM and human monocytes THP-1 cells in RPMI complete growth medium in T25 flasks at 37 degrees Celsius in a humidified chamber with 5%carbon dioxide.After three days, at 80 to 85%cell confluency, wash the A549 and MRC-5 cells with one milliliter of PBS for one minute. Next, harvest the cells by incubating them with 500 microliters of 0.25%trypsin EDTA solution for five minutes at 37 degrees Celsius. Then, immediately add four milliliters of complete growth medium to inactivate the trypsin.Collect the cell suspension into a 15 milliliter tube and pellet it down at 125 x g for five minutes. Remove the supernatant and resuspend the cells in a five milliliter complete growth medium. To establish multicellular tumor spheroids, count A549, MRC-5, and THP-1 cell numbers using a cell counter for one milliliter volume.After counting, prepare the cell suspension at a ratio of 5:4:1 and make up the volume to one milliliter with complete DMEM. Next, place a drop of 25 microliters of cell suspension mixture onto the cover of a 90 millimeter culture dish. Fill the bottom of the dish with 10 milliliters of sterile water.Carefully invert the lid over the water-filled hydration chamber and place the dish in a cell culture incubator for three days. On day four, monitor the spheroids under the microscope. To acquire images, switch on the power switch.Place the 90 millimeter culture dish on the stage and select the 10 x magnification. Adjust the lenses and examine the cells to analyze the cell aggregation and proliferation. Press the freeze and save buttons provided to capture the image.After imaging, replace the growth medium by carefully aspirating 20 microliters of medium from each droplet with a fresh medium. For live-dead imaging, switch on Ctr advanced, which is switch one, then the CPU and wait for the software system to boot. When booted, place the 90 millimeter dish containing spheroids onto the stage of the inverted fluorescent microscope.Then observe and capture images at 10 x magnification by selecting the fluorescence option in the software and selecting the FITC for the calcein and Texas Red channel. Next, select the option, live and view the image. Adjust the fluorescence intensity for appropriate optimization and click the safe button.Collect 200 tumors, spheroids each on day seven and 10 using a one milliliter pipette and a 15 milliliter tube. Then pellet the spheroids by centrifugation at 125 x g for five minutes and carefully aspirate the supernatant. Wash the spheroids with 200 microliters of PBS, centrifuge again and discard the supernatant.Add 400 microliters of 0.25%trypsin EDTA solution for spheroid disintegration and incubate at 37 degrees Celsius for 10 minutes. Perform vigorous pipetting for complete disintegration of the spheroids. Neutralize the trypsin by adding one milliliter of complete DMEM growth medium.Then centrifuge the spheroid suspension and discard the supernatant before resuspending the pellet in one milliliter of complete DMEM medium. Count the total number of cells as demonstrated. For the isolation of Cancer-Associated Fibroblasts or CAFs from the tumor spheroids, resuspend 1 x 10 to the seventh cells in 80 microliters of cold magnetic activated cell sorting or MACS buffer.Add 20 microliters of anti-fibroblast microbeads into the cell suspension, mix well by gently tapping the tube and incubating it at room temperature for 30 minutes. After incubation, wash the cells with one milliliter of cold MACS buffer. Then centrifuge and aspirate the supernatant before resuspending the pellet in 500 microliters of MACS buffer.For magnetic bead based cell separation, prepare the MACS column by rinsing it with three milliliters of MACS buffer. Place the cell suspension into the column and collect the flow through containing the unlabeled cell population. Next, wash the column thrice with three milliliters of MACS buffer before removing it from the separator.Then place the column on the collection tube. Collect the anti-fibroblast microbead labeled cells by adding five milliliters of MACS buffer and firmly pushing the plunger into the column. Centrifuge the labeled cells before proceeding for downstream applications.Count the number of isolated CAFs and use approximately 6 x 10 to the fourth cells for flow cytometry analysis. Wash the cells once with PBS, then centrifuge and aspirate the supernatant. Next, add 100 microliters of cell permeabilization buffer and incubate the cells at four degree Celsius for 30 minutes with intermittent vortexing to maintain a single cell suspension.Again, after centrifugation and resuspending the cells in permeabilization buffer, add two microliters of APC conjugated anti-human alpha SMA antibody and incubate at four degree Celsius for 45 minutes. After incubation, add one milliliter of permeabilization buffer and centrifuge to remove excess antibody. Resuspend the pellet in 400 microliters of permeabilization buffer for flow cytometry.Select ACTA2 positive cells after distinguishing the populations of cells based on their forward and side scatter. Selecting the singlet population followed by selecting the ACTA2 positive cells which appear as a single peak on the single parameter histogram. The development of multicellular tumor spheroids and live-dead analysis are shown here.On day seven, spheroids were compact and rigid with approximately 260 microns in diameter. On day 10, spheroids were 480 microns in diameter. In cell viability assay, a decrease in propidium iodide fluorescence and an increase in calcein-AM fluorescence from day seven to day 10 was observed.Hypoxic staining revealed a hypoxic core at the center of the day 10 spheroids. Furthermore, upregulation of E-cadherin and Mki-67 gene expression with the increase in days of tumor spheroid formation was observed. CAFs isolated from day 10 tumor spheroids were approximately 69%ACTA2 positive.The CAFs showed threefold upregulation in ACTA2 and tenfold in collagen type 1 alpha 2 chain compared to the MRC-5 fibroblasts. A significant increase in ROS levels on day 10 tumor spheroids was observed compared to day seven, suggesting the possible involvement of ROS generation on CAF activation. A significant increase was observed in cellular ROS levels in CAFs, isolated from day seven and day 10 tumor spheroids.Moreover, an alteration of mitochondrial membrane potential was seen by JC-1 staining. An induction of GLUT1 and MCT4 gene expression was observed in CAFs compared to normal fibroblasts. Significant induction of lactate dehydrogenase, Cytochrome C oxidase and succinate dehydrogenase enzyme activity were observed in CAFs compared to normal fibroblasts.A ratio of 5:4:1 of A549, MRC-5, and THP-1 cells must be used for the successful development of 3D multicellular tumor spheroid. Fibroblast population is critical for the rigidity of the tumor spheroids. Similar to cation solution and characterization, one can also use this tumor spheroid to obtain tumor associated macrophage cell population, which is an accomplice in tumor progression.This spheroid analysis would help us to understand how cancerous cells crossed fibroblast are involved in the CAFs activation, and also can be used to check the mitochondrial specific drug candidates.

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Research

JoVE Journal

Cancer Research

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment

This protocol demonstrates the capability of low-field electron paramagnetic resonance (EPR)-based techniques in combination with functional paramagnetic probes to provide quantitative information on the chemical tumor microenvironment (TME), including pO2, pH, redox status, concentrations of interstitial inorganic phosphate (Pi), and intracellular glutathione (GSH). In particular, an application of a recently developed soluble multifunctional trityl probe provides unsurpassed opportunity for in vivo concurrent measurements of pH, pO2 and Pi in Extracellular space (HOPE probe). The measurements of three parameters using a single probe allow for their correlation analyses independent of probe distribution and time of the measurements.

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment

Low-field (L-band, 1.2 GHz) electron paramagnetic resonance using soluble nitroxyl and trityl probes is demonstrated for assessment of physiologically important parameters in the tumor microenvironment in mouse models of breast cancer.

This protocol demonstrates the capability of low-field electron paramagnetic resonance (EPR)-based techniques in combination with functional paramagnetic ...

The Establishment of a Lung Colonization Assay for Circulating Tumor Cell Visualization in Lung Tissues

Metastasis is the major cause of cancer death. The role of circulating tumor cells (CTCs) in promoting cancer metastasis, in which lung colonization by CTCs critically contributes to early lung metastatic processes, has been vigorously investigated. As such, animal models are the only approach that captures the full systemic process of metastasis. Given that problems occur in previous experimental designs for examining the contributions of CTCs to blood vessel extravasation, we established an in vivo lung colonization assay in which a long-term-fluorescence cell-tracer, carboxyfluorescein succinimidyl ester (CFSE), was used to label suspended tumor cells and lung perfusion was performed to clear non-specifically trapped CTCs prior to lung removal, confocal imaging, and quantification. Polymeric fibronectin (polyFN) assembled on CTC surfaces has been found to mediate lung colonization in the final establishment of metastatic tumor tissues. Here, to specifically test the requirement of polyFN assembly on CTCs for lung colonization and extravasation, we performed short term lung colonization assays in which suspended Lewis lung carcinoma cells (LLCs) stably expressing FN-shRNA (shFN) or scramble-shRNA (shScr) and pre-labeled with 20 &#956;M of CFSE were intravenously inoculated into C57BL/6 mice. We successfully demonstrated that the abilities of shFN LLC cells to colonize the mouse lungs were significantly diminished in comparison to shScr LLC cells. Therefore, this short-term methodology may be widely applied to specifically demonstrate the ability of CTCs within the circulation to colonize the lungs.

An animal model is needed to decipher the role of circulating tumor cells (CTCs) in promoting lung colonization during cancer metastasis. Here, we established and successfully performed an in vivo assay to specifically test the requirement of polymeric fibronectin (polyFN) assembly on CTCs for lung colonization.

Metastasis is the major cause of cancer death. The role of circulating tumor cells (CTCs) in promoting cancer metastasis, in which lung colonization by ...

A 3D Spheroid Model as a More Physiological System for Cancer-Associated Fibroblasts Differentiation and Invasion In Vitro Studies

Defining the ideal model for an in vitro study is essential, mainly if studying physiological processes such as differentiation of cells. In the tumor stroma, host fibroblasts are stimulated by cancer cells to differentiate. Thus, they acquire a phenotype that contributes to the tumor microenvironment and supports tumor progression. By using the spheroid model, we have set up such a 3D in vitro model system, in which we analyzed the role of laminin-332 and its receptor integrin &#945;3&#946;1 in this differentiation process. This spheroid model system not only reproduces the tumor microenvironment conditions in a more accurate way, but also is a very versatile model since it allows different downstream studies, such as immunofluorescent staining of both intra- and extracellular markers, as well as deposited extracellular matrix proteins. Moreover, transcriptional analyses by qPCR, flow cytometry and cellular invasion can be studied with this model. Here, we describe a protocol of a spheroid model to assess the role of CAFs&#39; integrin &#945;3&#946;1 and its ectopically deposited ligand, laminin-332, in differentiation and in supporting the invasion of pancreatic cancer cells.

The goal of this protocol is to establish a 3D in vitro model to study the differentiation of cancer-associated fibroblasts (CAFs) in a tumor bulk-like environment, which can be addressed in different analysis systems, such as immunofluorescence, transcriptional analysis and life cell imaging.

Defining the ideal model for an in vitro study is essential, mainly if studying physiological processes such as differentiation of cells. In the tumor ...

Establishment and Characterization of Small Bowel Neuroendocrine Tumor Spheroids

Small bowel neuroendocrine tumors (SBNETs) are rare cancers originating from enterochromaffin cells of the gut. Research in this field has been limited because very few patient derived SBNET cell lines have been generated. Well-differentiated SBNET cells are slow growing and are hard to propagate. The few cell lines that have been established are not readily available, and after time in culture may not continue to express characteristics of NET cells. Generating new cell lines could take many years since SBNET cells have a long doubling time and many enrichment steps are needed in order to eliminate the rapidly dividing cancer-associated fibroblasts. To overcome these limitations, we have developed a protocol to culture SBNET cells from surgically removed tumors as spheroids in extracellular matrix (ECM). The ECM forms a 3-dimensional matrix that encapsulates SBNET cells and mimics the tumor micro-environment for allowing SBNET cells to grow. Here, we characterized the growth rate of SBNET spheroids and described methods to identify SBNET markers using immunofluorescence microscopy and immunohistochemistry to confirm that the spheroids are neuroendocrine tumor cells. In addition, we used SBNET spheroids for testing the cytotoxicity of rapamycin.

Neuroendocrine tumors (NETs) originate from neuroendocrine cells of the neural crest. They are slow growing and challenging to culture. We present an alternative strategy to grow NETs from the small bowel by culturing them as spheroids. These spheroids have small bowel NET markers and can be used for drug testing.

Small bowel neuroendocrine tumors (SBNETs) are rare cancers originating from enterochromaffin cells of the gut. Research in this field has been limited ...

A Mouse Model to Investigate the Role of Cancer-Associated Fibroblasts in Tumor Growth

Cancer-associated fibroblasts (CAFs) can play an important role in tumor growth by creating a tumor-promoting microenvironment. Models to study the role of CAFs in the tumor microenvironment can be helpful for understanding the functional importance of fibroblasts, fibroblasts from different tissues, and specific genetic factors in fibroblasts. Mouse models are essential for understanding the contributors to tumor growth and progression in an in vivo context. Here, a protocol in which cancer cells are mixed with fibroblasts and introduced into mice to develop tumors is provided. Tumor sizes over time and final tumor weights are determined and compared among groups. The protocol described can provide more insight into the functional role of CAFs in tumor growth and progression.

A protocol to co-inject cancer cells and fibroblasts and monitor tumor growth over time is provided. This protocol can be used to understand the molecular basis for the role of fibroblasts as regulators of tumor growth.

Cancer-associated fibroblasts (CAFs) can play an important role in tumor growth by creating a tumor-promoting microenvironment. Models to study the role ...

Isolation of Primary Cancer-Associated Fibroblasts from a Syngeneic Murine Model of Breast Cancer for the Study of Targeted Nanoparticles

Cancer-associated fibroblasts (CAFs) are key actors in the context of the tumor microenvironment. Despite being reduced in number as compared to tumor cells, CAFs regulate tumor progression and provide protection from antitumor immunity. Emerging anticancer strategies aim to remodel the tumor microenvironment through the ablation of pro-tumorigenic CAFs or reprogramming of CAFs functions and their activation status. A promising approach is the development of nanosized delivery agents able to target CAFs, thus allowing the specific delivery of drugs and active molecules. In this context, a cellular model of CAFs may provide a useful tool for in vitro screening and preliminary investigation of such nanoformulations.
This study describes the isolation and culture of primary CAFs from the syngeneic 4T1 murine model of triple-negative breast cancer. Magnetic beads were used in a 2-step separation process to extract CAFs from dissociated tumors. Immunophenotyping control was performed using flow cytometry after each passage to verify the process yield. Isolated CAFs can be employed to study the targeting capability of different nanoformulations designed to tackle the tumor microenvironment. Fluorescently labeled H-ferritin nanocages were used as candidate nanoparticles to set up the method. Nanoparticles, either bare or conjugated with a targeting ligand, were analyzed for their binding to CAFs. The results suggest that ex vivo extraction of breast CAFs may be a useful system to test and validate nanoparticles for the specific targeting of tumorigenic CAFs.

This paper aims to provide a protocol for the isolation and culture of primary cancer-associated fibroblasts from a syngeneic murine model of triple-negative breast cancer and their application for the preclinical study of novel nanoparticles designed to target the tumor microenvironment.&#160;

Cancer-associated fibroblasts (CAFs) are key actors in the context of the tumor microenvironment. Despite being reduced in number as compared to tumor ...

Exploring Mitochondrial Energy Metabolism of Single 3D Microtissue Spheroids Using Extracellular Flux Analysis

Three-dimensional (3D) cellular aggregates, termed spheroids, have become the forefront of in vitro cell culture in recent years. In contrast to culturing cells as two-dimensional, single-cell monolayers (2D culture), spheroid cell culture promotes, regulates, and supports physiological cellular architecture and characteristics that exist in vivo, including the expression of extracellular matrix proteins, cell signaling, gene expression, protein production, differentiation, and proliferation. The importance of 3D culture has been recognized in many research fields, including oncology, diabetes, stem cell biology, and tissue engineering. Over the last decade, improved methods have been developed to produce spheroids and assess their metabolic function and fate.
Extracellular flux (XF) analyzers have been used to explore mitochondrial function in 3D microtissues such as spheroids using either an XF24 islet capture plate or an XFe96 spheroid microplate. However, distinct protocols and the optimization of probing mitochondrial energy metabolism in spheroids using XF technology have not been described in detail. This paper provides detailed protocols for probing mitochondrial energy metabolism in single 3D spheroids using spheroid microplates with the XFe96 XF analyzer. Using different cancer cell lines, XF technology is demonstrated to be capable of distinguishing between cellular respiration in 3D spheroids of not only different sizes but also different volumes, cell numbers,&#160;DNA content and type.
The optimal mitochondrial effector compound concentrations of oligomycin, BAM15, rotenone, and antimycin A are used to probe specific parameters of mitochondrial energy metabolism in 3D spheroids. This paper also discusses methods to normalize data obtained from spheroids and addresses many considerations that should be considered when exploring spheroid metabolism using XF technology. This protocol will help drive research in advanced in vitro spheroid models.

These protocols will help users probe mitochondrial energy metabolism in 3D cancer cell-line-derived spheroids using Seahorse extracellular flux analysis.

Three-dimensional (3D) cellular aggregates, termed spheroids, have become the forefront of in vitro cell culture in recent years. In contrast to culturing ...

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 ...

Pancreatic Cancer-Derived Tumor Organoids and Fibroblasts from Fresh Tissue

Establishment of Pancreatic Cancer-Derived Tumor Organoids and Fibroblasts From Fresh Tissue

Tumor organoids are three-dimensional (3D) ex vivo tumor models that recapitulate the biological key features of the original primary tumor tissues. Patient-derived tumor organoids have been used in translational cancer research and can be applied to assess treatment sensitivity and resistance, cell-cell interactions, and tumor cell interactions with the tumor microenvironment. Tumor organoids are complex culture systems that require advanced cell culture techniques and culture media with specific growth factor cocktails and a biological basement membrane that mimics the extracellular environment. The ability to establish primary tumor cultures highly depends on the tissue of origin, the cellularity, and the clinical features of the tumor, such as the tumor grade. Furthermore, tissue sample collection, material quality and quantity, as well as correct biobanking and storage are crucial elements of this procedure. The technical capabilities of the laboratory are also crucial factors to consider. Here, we report a validated SOP/protocol that is technically and economically feasible for the culture of ex vivo tumor organoids from fresh tissue samples of pancreatic adenocarcinoma origin, either from fresh primary resected patient donor tissue or patient-derived xenografts (PDX). The technique described herein can be performed in laboratories with basic tissue culture and mouse facilities and is tailored for wide application in the translational oncology field.

Author Spotlight: Establishment of Pancreatic Cancer-Derived Tumor Organoids and Fibroblasts From Fresh Tissue  

Tumor organoids have revolutionized cancer research and the approach to personalized medicine. They represent a clinically relevant tumor model that allows researchers to stay one step ahead of the tumor in the clinic. This protocol establishes tumor organoids from fresh pancreatic tumor tissue samples and patient-derived xenografts of pancreatic adenocarcinoma origin.

Tumor organoids are three-dimensional (3D) ex vivo tumor models that recapitulate the biological key features of the original primary tumor tissues. ...

Examining Tumor Cell Dissemination from Lung Metastases

Tracking Tumor Cell Dissemination from Lung Metastases Using Photoconversion

Metastasis - the systemic spread of cancer - is the leading cause of cancer-related deaths. Although metastasis is commonly thought of as a unidirectional process wherein cells from the primary tumor disseminate and seed metastases, tumor cells in existing metastases can also redisseminate and give rise to new lesions in tertiary sites in a process known as &#34;metastasis-from-metastases&#34; or &#34;metastasis-to-metastasis seeding.&#34; Metastasis-to-metastasis seeding may increase the metastatic burden and decrease the patient&#39;s quality of life and survival. Therefore, understanding the processes behind this phenomenon is crucial to refining treatment strategies for patients with metastatic cancer.
Little is known about metastasis-to-metastasis seeding, due in part to logistical and technological limitations. Studies on metastasis-to-metastasis seeding rely primarily on sequencing methods, which may not be practical for researchers studying the exact timing of metastasis-to-metastasis seeding events or what promotes or prevents them. This highlights the lack of methodologies that facilitate the study of metastasis-to-metastasis seeding. To address this, we have developed - and describe herein - a murine surgical protocol for the selective photoconversion of lung metastases, allowing specific marking and fate tracking of tumor cells redisseminating from the lung to tertiary sites. To our knowledge, this is the only method for studying tumor cell redissemination and metastasis-to-metastasis seeding from the lungs that does not require genomic analysis.

Author Spotlight: Decoding Metastasis-to-Metastasis Seeding Using a New In Vivo Technique for Tracking Breast Cancer Spread 

We present a method for studying tumor cell redissemination from lung metastases involving a surgical protocol for the selective photoconversion of lung metastases, followed by the identification of redisseminated tumor cells in tertiary organs.

Metastasis - the systemic spread of cancer - is the leading cause of cancer-related deaths. Although metastasis is commonly thought of as a unidirectional ...