This work was supported by CONACyT FONSEC SSA/IMSS/ISSSTE Project No. 233061 to Ezequiel M. Fuentes-Panan&#225; and by Fondo de Apoyo a la Investigaci&#243;n, Hospital Infantil de M&#233;xico Federico G&#243;mez (project number HIM-2014-053). Espinoza-S&#225;nchez NA is a doctoral student from Programa de Doctorado en Ciencias Biom&#233;dicas, Universidad Nacional Aut&#243;noma de M&#233;xico (UNAM) and received fellowship 231663 from CONACYT. E-S NA, also acknowledge the financial support provided by the Mexican Institute of Social Security (IMSS).

Samples from BrC patients were obtained from the tissue bank of the Unidad de Investigaci&#243;n en Virolog&#237;a y C&#225;ncer, Hospital Infantil de M&#233;xico Federico G&#243;mez. This study was approved by the scientific, ethical, and biosecurity review boards of the Hospital Infantil de M&#233;xico Federico G&#243;mez: Comit&#233; de Investigaci&#243;n, Comit&#233; de &#201;tica en Investigaci&#243;n and Comit&#233; de Bioseguridad. All patients were prospectively enrolled and were informed about the nature of the ...

<ol>
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Epithelial cells grow in a 3D spatial conformation and their interaction with the ECM proteins is pivotal for tissue homeostasis. Many cancer studies have been based on cells grown in monolayers (2D) and although they have been critical to understanding many aspects of tumor formation and progression, monolayers do not recapitulate the characteristics that the ECM imposes on cells, for instance: limiting proliferation, adhesion-dependent cell survival, apical-basolateral polarity, ECM remodeling, cell differentiation, <e...

Tumor biology is far more intricate than previously thought. Mounting evidence shows that tumor cells are more than a mere bulk of uncontrolled proliferating cells; rather, different neoplastic cells seem to perform different functions displaying high organization and hierarchy within the tumor1. Tumor cells are also in intimate communication with non-transformed cells: macrophages, fibroblasts, lymphocytes, adipocytes, endothelial cells, among other cells are all immersed in the scaffold proteins and polysaccharides that constitute the ECM. Numerous direct and indirect interactions are established between transformed and non-transformed cells and with the ECM, which exerts a powerful influence over the disease outcome2,3. In the specific case of BrC, it is particularly important to dissect the communication of BrC cells with TAMs, considering that TAMs have been found to play a critical role in the evolution of the tumor, increasing the risk of metastasis and of disease recurrence4,5.
To analyze intra-tumoral interactions and their possible outcomes, new 3D in vitro approaches have been developed based on the use of ECM extracts that provide a much more complex microenvironment, closer to the reality of tumor biology, in comparison to the conventional monolayer cell cultures in which the cells grow attached to plastic. Petersen and Bissell6 provided the first model of nonmalignant and malignant mammary epithelial cells cultured on a laminin-rich basement membrane and were the first to describe the 3D organotypic structures that discriminate nonmalignant human breast epithelial cells from their malignant counterparts. A decade later, the model developed by Debnath, Muthuswamy, and Brugge7,8,9 provided a valuable tool to elucidate the biological pathways compromised during malignant transformation of glandular acini, such as large acini formation due to uncontrolled proliferation, delocalization of tight junction proteins as evidence of impaired cell polarization, and loss of acini lumen as a result of cell resistance to anoikis, a type of programmed cell death that occurs in anchorage-dependent cells when they detach from the surrounding ECM. The models of Sameni, Jedeszko, and Sloane have focused on imaging proteolytic activity by cells, which is closely related to invasiveness, another crucial trait of tumor malignancy10,11,12. These models rely on protein matrices mixed with different fluorescence-quenched protein substrates (DQ-gelatin, DQ-collagen I, and DQ-collagen IV), in which fluorescent signals are indicative of the proteolytic degradation of collagen. 3D models are also used to study stem cell properties of both non-transformed and tumor cells, in which cell aggregates, also termed spheroids, can be cultured in suspension or in ECM-like proteins interrogating for mechanisms of cell differentiation, asymmetric cell division, cell-to-cell adherence, and cell motility13,14. Invasion assays allow testing of the intrinsic aggressiveness of the tumor and the identification of the molecules that serve as chemoattractants during the invasive process15. Overall, 3D models represent an affordable diversification of in vitro cell culture that more closely reflect normal and oncogenic tissue morphogenesis.
We have designed a 3D cell co-culture system based on the aforementioned models7,10,11, using both human commercial BrC cell lines of known aggressive potential (luminal and triple-negative types) and primary cells explanted from BrC patients. We first developed a model where either non-aggressive (MCF-7) or aggressive (MDA-MB-231) BrC cells were co-cultured with U937 monocytes in an extracellular matrix extract (ECME)-based 3D system that allowed direct cell-cell interactions. These co-cultures were used to determine how the communication between these two cell lineages influenced the transcription of a set of genes related to cancer aggressive behavior. A significant increase of cyclooxygenase-2 (COX-2) transcript was observed that coincided with an increased production of one of its products, prostaglandin E2 (PGE2), a finding that highlighted the role of inflammation in cancer progression. Increased transcription of MMP was also observed that correlated with greater collagen proteolysis when aggressive MDA-MB-231 cells were co-cultured with U937 monocytes in DQ-Collagen IV-containing cultures. Of note, our co-cultures did not support the assumption that cell-cell interaction mechanisms are needed for collagen degradation. It rather suggested that communication between the two cell lineages was mediated by secreted molecules. Furthermore, the supernatants harvested from these co-culture assays contained soluble factors that disorganized glandular acini formed by non-transformed MCF-10A cells13. It was found that aggressive and primary BrC cells secreted elevated levels of monocyte chemotactic molecules MCP-1, GM-CSF, and RANTES. Thus, we outlined a 3D culture in which cells were separated in cell culture inserts to prevent cell-cell interactions. These cultures were used to address the indirect communication between BrC cells and monocytes. For these assays, non-aggressive and aggressive commercial BrC cell lines and primary BrC cells, and three different types of human monocytes: commercial U937 and THP-1 cells, and primary monocytes (PMs) isolated from peripheral blood of healthy donors (all monocytes were used in a non-activated state) were used. Increased concentrations of inflammatory cytokines IL-1&#946; and IL-8 were observed to be enriched in co-culture. Similarly, it was found that MMP-1, MMP-2, and MMP-10 were also increased in the BrC cells-monocyte co-cultures, and thus reinforcing previous findings14. In this manuscript, a point-by-point workflow of primary BrC cells isolation and testing in 3D cultures is presented along with representative results. This work constitutes a good example of the great potential that in vitro 3D cell systems provide to interrogate specific aspects of tumor biology.

<table border="0" cellpadding="0" cellspacing="0" style="width:1108px;" width="1108">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">U937</td>
			<td style="width:260px;">American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">CRL-1593.2</td>
			<td style="width:463px;">Monocytic cell line/histiocytic lymphoma&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">THP-1</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">TIB-202</td>
			<td>Monocytic cell line/acute monocytic leukemia&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">MCF-10A</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td>CRL-10317</td>
			<td>Non-transformed breast cell line</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">MCF-7</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">HTB-22</td>
			<td>Breast Cancer Cell line</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">T47D</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">HTB-133</td>
			<td>Breast Cancer Cell line</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">HS578T</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">HTB-126</td>
			<td>Breast Cancer Cell line</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">MDA-MB-231</td>
			<td>American Type Culture Collection ATCC&#160;</td>
			<td style="width:143px;">HTB-26</td>
			<td>Breast Cancer Cell line</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">RPMI 1640 medium</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">11875-093</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">DMEM High Glucose&#160;</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">11964-092</td>
			<td>4.5 g/L glucose</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">DMEM/F12</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">11039-021</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Antibiotic/Antimycotic</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">15240-062</td>
			<td>100 U/mL penicillin, 100 &#181;g/mL streptomycin, and 0.25 &#181;g/mL Fungizone</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Fetal Bovine Serum</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">16000-044</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Horse serum&#160;</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td>16050114</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">0.05% Trypsin-EDTA 1X</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td style="width:143px;">25300-062</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS 1X (Phosphate Buffered Saline</td>
			<td style="width:260px;">GIBCO BRL Life Technologies</td>
			<td>20012-027</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Epidermal Growth Factor (EGF)</td>
			<td>PeproTech</td>
			<td>AF-100-15 (1.00mg)</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Insulin</td>
			<td>SIGMA-ALDRICH</td>
			<td>I1882-100MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Hydrocortisone</td>
			<td>SIGMA-ALDRICH</td>
			<td>H088-5G</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cholera toxin Vibrio cholerae</td>
			<td>SIGMA-ALDRICH</td>
			<td>C8052-1MG</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Matrigel&#160;</td>
			<td>Corning Inc</td>
			<td>356237</td>
			<td style="width:463px;">Engelbreth-Holm-Swarm (EHS) mouse sarcoma, extracellular matrix extract, Store at -20&#176;C until use at 4&#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">GM-CSF</td>
			<td>PeproTech</td>
			<td>300-03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">MCP-1</td>
			<td>PeproTech</td>
			<td>300-04</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">RANTES</td>
			<td>PeproTech</td>
			<td>300-06</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">IL-8</td>
			<td>PeproTech</td>
			<td>200-08</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">IL-1&#946;</td>
			<td>PeproTech</td>
			<td>200-01B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Crystal-violet</td>
			<td>Hycel M&#233;xico</td>
			<td>541</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Paraformaldehyde</td>
			<td>SIGMA-ALDRICH</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Transwell permeable supports (inserts)</td>
			<td>Corning Inc</td>
			<td style="width:143px;">3422</td>
			<td>6.5 mm diameter, 8 &#181;m pore size/24-well plates&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Transwell permeable supports (inserts)</td>
			<td>Thermofisher Scientific</td>
			<td style="width:143px;">140620</td>
			<td>6.5 mm diameter, 0.4 &#181;m pore size/24-well plates&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Monocyte Isolation Kit II Human&#160;</td>
			<td style="width:260px;">Miltenyi Biotec</td>
			<td style="width:143px;">130-091-153</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">LS Columns</td>
			<td style="width:260px;">Miltenyi Biotec</td>
			<td style="width:143px;">130-042-401</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:243px;">Human Cytokine/Chemokine Magnetic Bead Panel Kit 96 Well Plate Assay</td>
			<td style="width:260px;">EMD Millipore</td>
			<td style="width:143px;">HCYTOMAG-60K</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:243px;">Magpix with xPonent software (laser based fluorescent analytical test instrumentation)</td>
			<td style="width:260px;">Luminex Corporation</td>
			<td style="width:143px;">40-072</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Lab-Tek chamber slide with cover (8 well)</td>
			<td style="width:260px;">Nalge Nunc International</td>
			<td style="width:143px;">177402</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Glass bottom microwell 35mm petri&#160; dishes</td>
			<td style="width:260px;">MatTek Corp.</td>
			<td style="width:143px;">P35G-1.5-14-C</td>
			<td></td>
		</tr>
	</tbody>
</table>

analyzing the communication between monocytes and primary breast cancer cells in an extracellular matrix extract (ecme)-based three-dimensional system

Embedded in the extracellular matrix (ECM), normal and neoplastic epithelial cells intimately communicate with hematopoietic and non-hematopoietic cells, thus greatly influencing normal tissue homeostasis and disease outcome. In breast cancer, tumor-associated macrophages (TAMs) play a critical role in disease progression, metastasis, and recurrence; therefore, understanding the mechanisms of monocyte chemoattraction to the tumor microenvironment and their interactions with tumor cells is important to control the disease. Here, we provide a detailed description of a three-dimensional (3D) co-culture system of human breast cancer (BrC) cells and human monocytes. BrC cells produced high basal levels of regulated on-activation, normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1), and granulocyte-macrophage colony-stimulating factor (G-CSF), while in co-culture with monocytes, pro-inflammatory cytokines Interleukin (IL)-1 beta (IL-1&#946;) and IL-8 were enriched together with matrix metalloproteinases (MMP)-1, MMP-2, and MMP-10. This tumor stroma microenvironment promoted resistance to anoikis in MCF-10A 3D acini-like structures, chemoattraction of monocytes, and invasion of aggressive BrC cells. The protocols presented here provide an affordable alternative to study intra-tumor communication and are an example of the great potential that in vitro 3D cell systems provide to interrogate specific features of tumor biology related to tumor aggression.

Morphological Analysis of BrC Cells in 3D Cultures:
The morphology of primary BrC cells growing in 3D cultures at low and high densities was studied over 5 days. During the first 48 h, cells adhere to the ECME and maintain a low density. At this time point, it can clearly be appreciated that cells present an elongated spindle-like shape, some with two or more long cytoplasmic projections and without showing appa...

Watch this Scientific Journal Video about Analyzing the Communication Between Monocytes and Primary Breast Cancer Cells in an Extracellular Matrix Extract ECME-based Three-dimensional System at JoVE.c

Analyzing the Communication Between Monocytes and Primary Breast Cancer Cells in an Extracellular Matrix Extract ECME-based Three-dimensional System

Here, we describe a three-dimensional culture method to analyze the morphology of primary breast cancer cells, as well as to study their direct/indirect interactions with monocytes and the outcomes such as collagen degradation, immune cell recruitment, cell invasion, and promotion of cancer-related inflammation.

Analyzing the Communication Between Monocytes and Primary Breast Cancer Cells in an Extracellular Matrix Extract (ECME)-based Three-dimensional System

Embedded in the extracellular matrix (ECM), normal and neoplastic epithelial cells intimately communicate with hematopoietic and non-hematopoietic cells, ...

The overall goal of this protocol is to study the direct and indirect communication between primary breast cancer cells and monocytes in a three-dimensional co-culture system. This method can help answer key questions in inflammatory microenvironment of breast cancer field such as how immune cells are regraded and activated, how these cells help to sustain the tumor inflammatory microenvironment and how these microenvironment facilitates tumor cell invasion. The main advantage of this technique is that it provides an affordable alternative to study intra-tumor communication and illustrates the potential of in vitro, 3-D cell systems for interrogating specific features of tumor biology.Particularly those related to tumor aggression. To begin, cultivate two times 10 to the sixth U937 and THP1 monocytes in 10 milliliters of RPMI1640 medium, supplemented with 10 percent FBS and one percent antibiotic antimycotic. Also cultivate fresh PMs in supplemented DMEMF12 medium.Incubate the cells at 37 degrees Celsius in a humidified five percent carbon dioxide environment. Plate four time 10 to the fifth monocytes in one milliliter per well of their corresponding medium. Place an insert in each well and add 900 microliters of the four times 10 to the fifth BrC cell suspension in the corresponding medium.Incubate the cultures at 37 degrees Celsius in a humidified five percent carbon dioxide environment for five days and recover the supernatants. Retrieve the cells by trypsinization if subsequent analysis is performed. Include controls of individual cell cultures with the respective media.To label BrC cells and monocytes with commercially available cumerine and rhodamine before cell culture, prepare a monolayer of two times 10 to the sixth BrC cells of interest and replace the standard medium with sufficient, pre-warmed working solution of the fluorescent dye. Incubate the cells at 37 degrees Celsius in a humidified five percent carbon dioxide environment for 30 minutes. Then aspirate the dye solution and use sufficient one XPBS to gently rinse the cells.Aspirate the PBS and add the standard medium. To trypsinize the cells, add two milliliters of 05 percent trypsin and 0.48 millimolar EDTA to the flask and incubate the cells at 37 degrees Celsius for five to 10 minutes. Add 200 microliters of FBS to stop the trypsinization and seven milliliters of the corresponding medium without supplements.Re-suspend the cells by pipetting, then transfer 10 microliters of the cells to a Nuebauer chamber and count them. Next, pellet the cells at 430 times g and room temperature for five minutes, then discard the supernatant and use three milliliters of pre-warmed fluorescent dye working solution to re-suspend the cells. Incubate the cell suspension at 37 degrees Celsius in a humidified five percent carbon dioxide environment for 30 minutes.After pelleting the cells again, discard the dye working solution and use five to seven milliliters of one XPBS to gently re-suspend the cells. Then, after pelleting the cells once more and discarding the PBS, re-suspend the cells in five to seven milliliters of standard medium. Count 10 microliters of the cell suspension.Set up a co-culture by spreading enough ECME at the bottom of the well to form an even layer in each well of a four well chamber slide system. Plate 20 microliters of a single cell suspension containing five time 10 to the fifth labeled BrC cells per well. After 15 to 20 minutes at 37 degrees celsius, add a suspension of 2.5 times 10 to the fifth labeled monocytes in 80 microliters of assay medium supplemented with 60 percent ECME.Allow the ECME to solidify at 37 degrees Celsius for 15 to 20 minutes. Now add one milliliter of a one to one mixture of the BrC cells and monocyte culture medium. Incubate the co-cultures at 37 degrees Celsius in a humidified five percent carbon dioxide environment for 24 hours, 48 hours, or five days to track changes at different time points.To degrade the ECM proteins and recover the cells from the cultures, aspirate and discard the medium, then add 0.5 milliliters of one XPBS with 0.1 percent trypsin and 0.25 percent EDTA to the culture. Incubate the cells at 37 degrees Celsius for three hours. Following the incubation, add 0.5 milliliters of one XPBS with 10 percent FBS to neutralize the trypsin and re-suspend the cells by vigorously pipetting to attain a single cell suspension.After pelleting the cells, discard the supernatant and re-suspend the cells in five milliliters of one XPBS with 10 percent FBS. Repeat this step once. Subject the cell suspension to fax with the appropriate instrument.Ensure that the final populations are at least 95 percent pure. In each well of an eight well chamber slide system spread a 40 microliter base of ECME and let it solidify at 37 degrees Celsius for 30 minutes. Seed 800 MCF10 A cells per well in 400 microliters of supplemented DMEM F12 culture medium according to the text protocol.Then add 400 microliters of conditioned medium or supplemented DMEM F12 culture medium with 20 nanograms per milliliter of human recombinant IL1 beta. Place the chamber slide into a glass petri dish containing a 35 milliliter petri dish filled with two milliliters of PBS. The MCF 10A cells should be seeded in each well very slowly to avoid damage of the base of ECME and to prevent cells from settling down and forming a monoly.Using an optical microscope record glandular acini formation every 24 hours for 14 days. After 14 days of culture, add 100 microliters of 100 nanomolar dapy in one XPBS and incubate the samples at room temperature with constant stirring for 25 minutes. Rinse the samples with one XPBS at room temperature, three times for five minutes each with constant stirring.Use mounting medium specific for fluorescent staining to mount the preparations. Then seal the mounted samples with transparent polish and maintain the slides, protected from light at four degrees Celsius. Demonstrating the procedure in the confocal microscope will be Vadim Perez, a researcher from The National Laboratory of Advanced Microscoping.Analyze the acini with a confocal microscope taking images of transversal stacks at different depths of the acini. Visualize different cellular proteins in the acini with proper staining protocols. For example, caheren was stained here to assess cell to cell adhesion, cell polarity, and oralimen formation.The morphology of primary BrC cells growing in 3D cultures at low and high densities was studied over five days. During the first 48 hours, cells adhere to the ECME with an elongated spindle shape and form knit-like structures at five days. After five days in 3D co-cultures, both MCF7 and MDA-MB-231 commercial BrC cells formed disorganized aggregates.However, aggressive MDA-MB-231 cells for aggregates with elongated forms, while non-aggressive MCF7 cells for aggregates with rounded shapes that are more densely compacted then MDA-MB-231 cells. The supernatants from indirect interaction 3D primary BrC cultures and their five day co-cultures with primary monocytes were harvested. Significantly increased levels of IL1 beta and IL8 were observed in the primary BrC cell monocyte co-cultures.Both crucial and flammatory cytokines that have been previously associated with malignant progression. MCF10A cells were cultivated with two different supernatants from two primary BrC cell lines to observe lumen formation as a measure of resistance to anoykis. Unlike MCF10A cells grown under standard conditions, bi-confocal microscopy at day 14, transversal cuts of the spheroids show that MCF10A cells evaded anoykis as measured by counting the number of central cells in the acini.Following this procedure, other methods like medical analysis can be performed in order to answer additional questions. Test the signaling pathways in both cancer migration. After its development this technique paved the way for researchers in the field of tumor micro-environments to explore the communications of breast cancer cells with mass cells, fibroblasts, neutrofils, or even different clones of tumor cells in 3D co-culture systems.After watching this video, you should have a good understanding of how to establish a 3D culture system to model the tumor microenvironment.

analyzing-communication-between-monocytes-primary-breast-cancer-cells

Research

JoVE Journal

Cancer Research

Utilizing Functional Genomics Screening to Identify Potentially Novel Drug Targets in Cancer Cell Spheroid Cultures

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery of the next generation of novel drug targets. It is becoming apparent that more complex models of cancer are required to fully appreciate the contributing factors that drive tumorigenesis in vivo and increase the efficacy of novel therapies that make the transition from pre-clinical models to clinical trials.
Here we present a methodology for generating uniform and reproducible tumor spheroids that can be subjected to siRNA functional screening. These spheroids display many characteristics that are found in solid tumors that are not present in traditional two-dimension culture. We show that several commonly used breast cancer cell lines are amenable to this protocol. Furthermore, we provide proof-of-principle data utilizing the breast cancer cell line BT474, confirming their dependency on amplification of the epidermal growth factor receptor HER2 and mutation of phosphatidylinositol-4,5-biphosphate 3-kinase (PIK3CA) when grown as tumor spheroids. Finally, we are able to further investigate and confirm the spatial impact of these dependencies using immunohistochemistry.

Identifying novel drug targets that transition from pre-clinical testing to human trials is a scientific priority. To that end, here we describe a functional genomics approach for examining the impact of gene depletion on cancer cell line spheroids, which more appropriately model human cancers in vivo.

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery ...

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. ...

A Preclinical Mouse Model of Osteosarcoma to Define the Extracellular Vesicle-mediated Communication Between Tumor and Mesenchymal Stem Cells

Within the tumor microenvironment, resident or recruited mesenchymal stem cells (MSCs) contribute to malignant progression in multiple cancer types. Under the influence of specific environmental signals, these adult stem cells can release paracrine mediators leading to accelerated tumor growth and metastasis. Defining the crosstalk between tumor and MSCs is of primary importance to understand the mechanisms underlying cancer progression and identify novel targets for therapeutic intervention. 
Cancer cells produce high amounts of extracellular vesicles (EVs), which can profoundly affect the behavior of target cells in the tumor microenvironment or at distant sites. Tumor EVs enclose functional biomolecules, including inflammatory RNAs and (onco)proteins, that can educate stromal cells to enhance the metastatic behavior of cancer cells or to participate in the pre-metastatic niche formation. In this article, we describe the development of a preclinical cancer mouse model that enables specific evaluation of the EV-mediated crosstalk between tumor and mesenchymal stem cells. First, we describe the purification and characterization of tumor-secreted EVs and the assessment of the EV internalization by MSCs. We then make use of a multiplex bead-based immunoassay to evaluate the alteration of the MSC cytokine expression profile induced by cancer EVs. Finally, we illustrate the generation of a bioluminescent orthotopic xenograft mouse model of osteosarcoma that recapitulates the tumor-MSC interaction, and show the contribution of EV-educated MSCs to tumor growth and metastasis formation. 
Our model provides the opportunity to define how cancer EVs shape a tumor-supporting environment, and to evaluate whether blockade of the EV-mediated communication between tumor and MSCs prevents cancer progression.

Direct injection of cancer-derived extracellular vesicles (EVs) leads to reprogramming of bone marrow supporting tumor progression; however, which cells mediate this effect is unclear. Herein, we describe a step-by-step protocol to investigate EV-mediated tumor-mesenchymal stem cell (MSC) interactions in vivo, revealing a crucial role for EV-educated MSCs in metastasis.

Within the tumor microenvironment, resident or recruited mesenchymal stem cells (MSCs) contribute to malignant progression in multiple cancer types. Under ...

Fabrication of Tongue Extracellular Matrix and Reconstitution of Tongue Squamous Cell Carcinoma In Vitro

In order to construct an effective and realistic model for tongue squamous cell carcinoma (TSCC) in vitro, the methods were created to produce decellularized tongue extracellular matrix (TEM) which provides functional scaffolds for TSCC construction. TEM provides an in vitro niche for cell growth, differentiation, and cell migration. The microstructures of native extracellular matrix (ECM) and biochemical compositions retained in the decellularized matrix provide tissue-specific niches for anchoring cells. The fabrication of TEM can be realized by deoxyribonuclease (DNase) digestion accompanied with a serious of organic or inorganic pretreatment. This protocol is easy to operate and ensures high efficiency for the decellularization. The TEM showed favorable cytocompatibility for TSCC cells under static or stirred culture conditions, which enables the construction of the TSCC model. A self-made bioreactor was also used for the persistent stirred condition for cell culture. Reconstructed TSCC using TEM showed the characteristics and properties resembling clinical TSCC histopathology, suggesting the potential in TSCC research.

Fabrication of Tongue Extracellular Matrix and Reconstitution of Tongue Squamous Cell Carcinoma In Vitro

A method is shown here for the preparation of the tongue extracellular matrix (TEM) with efficient decellularization. The TEM can be used as functional scaffolds for the reconstruction of a tongue squamous cell carcinoma (TSCC) model under static or stirred culture conditions.

In order to construct an effective and realistic model for tongue squamous cell carcinoma (TSCC) in vitro, the methods were created to produce ...

A Three-dimensional Thymic Culture System to Generate Murine Induced Pluripotent Stem Cell-derived Tumor Antigen-specific Thymic Emigrants

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a promising source for adoptive T cell therapy (ACT). However, classical in vitro methods for producing regenerated T cells from iPSC result in either innate-like or terminally differentiated T cells, which are phenotypically and functionally distinct from na&#239;ve T cells. Recently, a novel three-dimensional (3D) thymic culture system was developed to generate a homogenous subset of CD8&#945;&#946;+ antigen-specific T cells with a na&#239;ve T cell-like functional phenotype, including the capacity for proliferation, memory formation, and tumor suppression in vivo. This protocol avoids aberrant developmental fates, allowing for the generation of clinically relevant iPSC-derived T cells, designated as iPSC-derived thymic emigrants (iTE), while also providing a potent tool to elucidate the subsequent functions necessary for T cell maturation after thymic selection.

This article describes a novel method to generate tumor antigen-specific induced pluripotent stem cell-derived thymic emigrants (iTE) by a three-dimensional (3D) thymic culture system. iTE are a homogenous subset of T cells closely related to na&#239;ve T cells with the capacity for proliferation, memory formation, and tumor suppression.

The inheritance of pre-rearranged T cell receptors (TCRs) and their epigenetic rejuvenation make induced pluripotent stem cell (iPSC)-derived T cells a ...

Three-Dimensional Bone Extracellular Matrix Model for Osteosarcoma

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with diagnostic or prognostic difficulties. OS comprises genotypically and phenotypically heterogeneous cancer cells. Bone microenvironment elements are proved to account for tumor heterogeneity and disease progression. Bone extracellular matrix (BEM) retains the microstructural matrices and biochemical components of native extracellular matrix. This tissue-specific niche provides a favorable and long-term scaffold for OS cell seeding and proliferation. This article provides a protocol for the preparation of BEM model and its further experimental application. OS cells can grow and differentiate into multiple phenotypes consistent with the histopathological complexity of OS clinical specimens. The model also allows visualization of diverse morphologies and their association with genetic alterations and underlying regulatory mechanisms. As homologous to human OS, this BEM-OS model can be developed and applied to the pathology and clinical research of OS.

The bone extracellular matrix (BEM) model for osteosarcoma (OS) is well established and shown here. It can be used as a suitable scaffold for mimicking primary tumor growth in vitro and providing an ideal model for studying the histologic and cytogenic heterogeneity of OS.

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with ...

Capturing Small Molecule Communication Between Tissues and Cells Using Imaging Mass Spectrometry

Imaging mass spectrometry (IMS) has routinely been applied to three types of samples: tissue sections, spheroids, and microbial colonies. These sample types have been analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to visualize the distribution of proteins, lipids, and metabolites across the biological sample of interest. We have developed a novel sample preparation method that combines the strengths of the three previous applications to address an underexplored approach for identifying chemical communication in cancer, by seeding mammalian cell cultures into agarose in coculture with healthy tissues followed by desiccation of the sample. Mammalian tissue and cells are cocultured in close proximity allowing chemical communication via diffusion between the tissue and cells. At specific time points, the agarose-based sample is dried in the same manner as microbial colonies prepared for IMS analysis. Our method was developed to model the communication between high grade serous ovarian cancer derived from the fallopian tube as it interacts with the ovary during metastasis. Optimization of the sample preparation resulted in the identification of norepinephrine as a key chemical component in the ovarian microenvironment. This newly developed method can be applied to other biological systems that require an understanding of chemical communication between adjacent cells or tissues.

A novel method of sample preparation was developed to accommodate cell and tissue coculture to detect small molecule exchange using imaging mass spectrometry.

Imaging mass spectrometry (IMS) has routinely been applied to three types of samples: tissue sections, spheroids, and microbial colonies. These sample ...

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 ...

Differentiation of Mouse Breast Epithelial HC11 and EpH4 Cells

Cadherins play an important role in the regulation of cell differentiation as well as neoplasia. Here we describe the origins and methods of the induction of differentiation of two mouse breast epithelial cell lines, HC11 and EpH4, and their use to study complementary stages of mammary gland development and neoplastic transformation.
The HC11 mouse breast epithelial cell line originated from the mammary gland of a pregnant Balb/c mouse. It differentiates when grown to confluence attached to a plastic Petri dish surface in medium containing fetal calf serum and Hydrocortisone, Insulin and Prolactin (HIP medium). Under these conditions, HC11 cells produce the milk proteins &#946;-casein and whey acidic protein (WAP), similar to lactating mammary epithelial cells, and form rudimentary mammary gland-like structures termed &#34;domes&#34;.
The EpH4 cell line was derived from spontaneously immortalized mouse mammary gland epithelial cells isolated from a pregnant Balb/c mouse. Unlike HC11, EpH4 cells can fully differentiate into spheroids (also called mammospheres) when cultured under three-dimensional (3D) growth conditions in HIP medium. Cells are trypsinized, suspended in a 20% matrix consisting of a mixture of extracellular matrix proteins produced by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells, plated on top of a layer of concentrated matrix coating a plastic Petri dish or multiwell plate, and covered with a layer of 10% matrix-containing HIP medium. Under these conditions, EpH4 cells form hollow spheroids that exhibit apical-basal polarity, a hollow lumen, and produce &#946;-casein and WAP.
Using these techniques, our results demonstrated that the intensity of the cadherin/Rac signal is critical for the differentiation of HC11 cells. While Rac1 is necessary for differentiation and low levels of activated RacV12 increase differentiation, high RacV12 levels block differentiation while inducing neoplasia. In contrast, EpH4 cells represent an earlier stage in mammary epithelial differentiation, which is inhibited by even low levels of RacV12.

We describe techniques for differentiation induction of two breast epithelial lines, HC11 and EpH4. While both require fetal calf serum, insulin, and prolactin to produce milk proteins, EpH4 cells can fully differentiate into mammospheres in three-dimensional culture. These complementary models are useful for signal transduction studies of differentiation and neoplasia.

Cadherins play an important role in the regulation of cell differentiation as well as neoplasia. Here we describe the origins and methods of the induction ...

Modeling Breast Cancer in Human Breast Tissue using a Microphysiological System

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials. Therefore, new models are needed to improve our understanding of the disease. The NIH Microphysiological Systems (MPS) program was developed to improve the clinical translation of basic science discoveries and promising new therapeutic strategies. Here we present a method for generating MPS for breast cancers (BC-MPS). This model adapts a previously described approach of culturing primary human white adipose tissue (WAT) by sandwiching WAT between adipose-derived stem cell sheets (ASC)s. Novel aspects of our BC-MPS include seeding BC cells into non-diseased human breast tissue (HBT) containing native extracellular matrix, mature adipocytes, resident fibroblasts, and immune cells; and sandwiching the BC-HBT admixture between HBT-derived ASC sheets. The resulting BC-MPS is stable in culture ex vivo for at least 14 days. This model system contains multiple elements of the microenvironment that influence BC including adipocytes, stromal cells, immune cells, and the extracellular matrix. Thus BC-MPS can be used to study the interactions between BC and its microenvironment. 
We demonstrate the advantages of our BC-MPS by studying two BC behaviors known to influence cancer progression and metastasis: 1) BC motility and 2) BC-HBT metabolic crosstalk. While BC motility has previously been demonstrated using intravital imaging, BC-MPS allows for high-resolution time-lapse imaging using fluorescence microscopy over several days. Furthermore, while metabolic crosstalk was previously demonstrated using BC cells and murine pre-adipocytes differentiated into immature adipocytes, our BC-MPS model is the first system to demonstrate this crosstalk between primary human mammary adipocytes and BC cells in vitro.

This protocol describes the construction of an in vitro microphysiological system for studying breast cancer using primary human breast tissue with off the shelf materials.

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs ...