Name: studying the effects of tumor-secreted paracrine ligands on macrophage activation using co-culture with permeable membrane supports
Uploaded: 2019-11-28T13:30:00
Description: Watch this Scientific Journal Video about Studying the Effects of Tumor-Secreted Paracrine Ligands on Macrophage Activation using Co-Culture with Permeable Membrane Supports at JoVE.com

Eric Ubil was funded, in part, by the American Cancer Society Postdoctoral Fellowship (128770-PF-15-216-01-LIB). The work was supported by a grant from the NIH (R01-CA205398) and a Breast Cancer Research Foundation award (BCRF-18-041) to HSE.

All procedures related to the harvest and use of murine peritoneal macrophages were conducted at the University of North Carolina at Chapel Hill (UNC) and were approved by the UNC Institutional Animal Care and Use Committee (IACUC).
1. Macrophage culture
NOTE: This procedure can utilize primary peritoneal macrophages (described in detail below), bone marrow-derived macrophages, or macrophage cell lines such as J774 (ATCC) or RAW264 (ATCC).
<ol>
	<li>Harvest perito...

<ol>
	<li>Freeman, G. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engagement+of+the+PD-1+immunoinhibitory+receptor+by+a+novel+B7+family+member+leads+to+negative+regulation+of+lymphocyte+activation.">Engagement of the PD-1 immunoinhibitory receptor by a novel B7 family member leads to negative regulation of lymphocyte activation.</a> Journal of Experimental Medicine. 192 (7), 1027-1034 (2000).</li><li>Agata, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+the+PD-1+antigen+on+the+surface+of+stimulated+mouse+T+and+B+lymphocytes.">Expression of the PD-1 antigen on the surface of stimulated mouse T and B lymphocytes.</a> International Immunology. 8 (5), 765-772 (1996).</li><li>Dong, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-associated+B7-H1+promotes+T-cell+apoptosis:+a+potential+mechanism+of+immune+evasion.">Tumor-associated B7-H1 promotes T-cell apoptosis: a potential mechanism of immune evasion.</a> Nature Medicine. 8 (8), 793-800 (2002).</li><li>Sznol, M., Chen, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antagonist+antibodies+to+PD-1+and+B7-H1+(PD-L1)+in+the+treatment+of+advanced+human+cancer--response.">Antagonist antibodies to PD-1 and B7-H1 (PD-L1) in the treatment of advanced human cancer--response.</a> Clinical Cancer Research. 19 (19), 5542 (2013).</li><li>Kortylewski, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+the+IL-23+and+IL-12+balance+by+Stat3+signaling+in+the+tumor+microenvironment.">Regulation of the IL-23 and IL-12 balance by Stat3 signaling in the tumor microenvironment.</a> Cancer Cell. 15 (2), 114-123 (2009).</li><li>Halak, B. K., Maguire, H. C., Lattime, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-induced+interleukin-10+inhibits+type+1+immune+responses+directed+at+a+tumor+antigen+as+well+as+a+non-tumor+antigen+present+at+the+tumor+site.">Tumor-induced interleukin-10 inhibits type 1 immune responses directed at a tumor antigen as well as a non-tumor antigen present at the tumor site.</a> Cancer Research. 59 (4), 911-917 (1999).</li><li>Wang, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+the+innate+and+adaptive+immune+responses+by+Stat-3+signaling+in+tumor+cells.">Regulation of the innate and adaptive immune responses by Stat-3 signaling in tumor cells.</a> Nature Medicine. 10 (1), 48-54 (2004).</li><li>Mazzoni, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloid+suppressor+lines+inhibit+T+cell+responses+by+an+NO-dependent+mechanism.">Myeloid suppressor lines inhibit T cell responses by an NO-dependent mechanism.</a> The Journal of Immunology. 168 (2), 689-695 (2002).</li><li>Zea, A. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arginase-producing+myeloid+suppressor+cells+in+renal+cell+carcinoma+patients:+a+mechanism+of+tumor+evasion.">Arginase-producing myeloid suppressor cells in renal cell carcinoma patients: a mechanism of tumor evasion.</a> Cancer Research. 65 (8), 3044-3048 (2005).</li><li>Steele, R. J., Eremin, O., Brown, M., Hawkins, R. 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+high+macrophage+content+in+human+breast+cancer+is+not+associated+with+favourable+prognostic+factors.">A high macrophage content in human breast cancer is not associated with favourable prognostic factors.</a> British Journal of Surgery. 71 (6), 456-458 (1984).</li><li>Evans, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+T-+and+B+lymphocyte+responses+to+mitogens+by+tumor-associated+macrophages:+the+dependency+on+the+stage+of+tumor+growth.">Regulation of T- and B lymphocyte responses to mitogens by tumor-associated macrophages: the dependency on the stage of tumor growth.</a> Journal of Leukocyte Biology. 35 (6), 549-559 (1984).</li><li>Noy, R., Pollard, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-associated+macrophages:+from+mechanisms+to+therapy.">Tumor-associated macrophages: from mechanisms to therapy.</a> Immunity. 41 (1), 49-61 (2014).</li><li>Pollard, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour-educated+macrophages+promote+tumour+progression+and+metastasis.">Tumour-educated macrophages promote tumour progression and metastasis.</a> Nature Reviews Cancer. 4 (1), 71-78 (2004).</li><li>Renaud, J., Martinoli, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+Insert+Co-culture+System+of+Two+Cellular+Types+in+the+Absence+of+Cell-Cell+Contact.">Development of an Insert Co-culture System of Two Cellular Types in the Absence of Cell-Cell Contact.</a> Journal of Visualized Experiments. (113), e54356 (2016).</li><li>Dasari, S., Pandhiri, T., Haley, J., Lenz, D., Mitra, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Proximal+Culture+Method+to+Study+Paracrine+Signaling+Between+Cells.">A Proximal Culture Method to Study Paracrine Signaling Between Cells.</a> Journal of Visualized Experiments. (138), e58144 (2018).</li><li>Ubil, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor-secreted+Pros1+inhibits+macrophage+M1+polarization+to+reduce+antitumor+immune+response.">Tumor-secreted Pros1 inhibits macrophage M1 polarization to reduce antitumor immune response.</a> Journal of Clinical Investigation. 128 (6), 2356-2369 (2018).</li><li>Ray, A., Dittel, B. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+mouse+peritoneal+cavity+cells.">Isolation of mouse peritoneal cavity cells.</a> Journal of Visualized Experiments. (35), e1488 (2010).</li><li>Zaks-Zilberman, M., Zaks, T. Z., Vogel, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+proinflammatory+and+chemokine+genes+by+lipopolysaccharide+and+paclitaxel+(Taxol)+in+murine+and+human+breast+cancer+cell+lines.">Induction of proinflammatory and chemokine genes by lipopolysaccharide and paclitaxel (Taxol) in murine and human breast cancer cell lines.</a> Cytokine. 15 (3), 156-165 (2001).</li></ol>

The co-culture assay presented here is a modification of previously established assays that allows for the study of tumor-secreted factors on immune cell activation. While cell-cell contact is known to induce changes in immune activity, the ability of tumor-secreted ligands to modulate immune activation is less well understood. We describe a method which, unlike direct co-culture, can be used to interrogate how tumor-derived secreted factors impact immune cell activation without the confounding nature of contact-mediated...

Recent studies have focused on the ability of cancer cells to avoid detection by immune cells, suppress local immune activation, or to produce a tolerogenic tumor-permissive milieu in the tumor microenvironment. Two broad classes of tumor and immune cell interactions have been described that facilitate these effects: contact-mediated interactions or tumor-secreted ligands. One of the most well-studied and clinically tractable mechanisms of contact-mediated immune inhibition utilized by tumors is the expression of PD-L1, which interacts with PD-1 on T cells to inhibit their activation and function1,2. In response to interferon-gamma (IFN&#947;), which is expressed by a number of activated immune cells, tumor cells can increase expression of PD-L1 to induce exhaustion of PD-1&#8211;expressing activated T cells, thereby preventing them from effectively eradicating tumor cells3. The use of antibodies to block the interaction between PD-L1 and PD-1 is currently used to treat multiple cancer types in humans4. In light of this clinical success and others, the identification and targeting of tumor-derived immunosuppressive mechanisms has received increasing attention.
Beyond suppression of adaptive immunity, tumors are also known to secrete factors that suppress the pro-inflammatory responses of innate immune cells. Tumor-derived or tumor-induced secretions, including IL-6, IL-10, VEGF, IL-23, and colony stimulating factor (CSF-1), have been shown to inhibit antitumor responses of natural killer (NK) cells, granulocytes, and dendritic cells in the tumor microenvironment5,6,7. Tumor cells can also secrete factors that skew the recruitment and differentiation of myeloid-derived cells in the tumor microenvironment to promote suppression of T cell activation8,9.
One type of innate immune cell that has a profound effect on tumor progression is the macrophage. For many years, the presence of tumor-associated macrophages (TAMs) has been used as a negative prognostic of patient survival10. The concept that immunosuppressive TAMs dampen immune cell-mediated clearance of tumors was introduced more than 40 years ago11. More recently, it has been shown that the macrophage pro-inflammatory response can be downregulated while a pro-tumor phenotype can be induced in the tumor microenvironment. These immunosuppressive macrophages can contribute to a tolerogenic response, driving tumor progression and resistance to chemo- and immunotherapy12. Given that macrophages are often one of the most abundant leukocytes with the tumor, restoration of their tumor-specific immune activity represents a potential target for anticancer therapeutics13.
While contact-mediated interactions between tumor cells and macrophages can be modeled through direct coculture, the use of permeable membrane supports can elucidate which tumor-secreted factors are immunomodulatory without the potentially confounding influence of tumor-immune cell-cell contact. Using somewhat similar methods, others have demonstrated the potential of identifying secreted factors in microglia/neuronal interactions14 as well as tumor cells with mesothelial cells15. We have also successfully used this co-culture technique to characterize the role of a tumor-secreted protein, Pros1, as a suppressor of pro-inflammatory gene expression after the stimulation of peritoneal macrophages with LPS and interferon-gamma16. Here we describe a straightforward methodology that can be used to interrogate how tumor-secreted factors can affect macrophage activation.

<table border="0" cellpadding="0" cellspacing="0" style="width:1419px;" width="1418">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:444px;">B16-F10</td>
			<td style="width:244px;">ATCC</td>
			<td style="width:344px;">ATCC CRL-6475</td>
			<td style="width:387px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">cDNA synthesis kit</td>
			<td>Promega</td>
			<td>A3500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM/F12 media</td>
			<td>ThermoFisher Scientific- Gibco</td>
			<td>11320033</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fetal Bovine Serum</td>
			<td>Millipore</td>
			<td>TMS-013-B</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">J774A.1</td>
			<td>ATCC</td>
			<td>ATCC TIB-67</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Lipopolysaccharides from Escherichia coli O111:B4</td>
			<td>Sigma-Aldrich</td>
			<td>L5293-2ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Murine M-CSF</td>
			<td>Prospec</td>
			<td>CYT-439</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin-Streptomycin (10,000 U/mL)</td>
			<td>ThermoFisher Scientific- Gibco</td>
			<td>15140122</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Pros1 ELISA</td>
			<td>MyBioSource</td>
			<td>MBS2886720</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RAW264.7</td>
			<td>ATCC</td>
			<td>ATCC TIB-71</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Recombinant Mouse IFN&#947;</td>
			<td>BioLegend</td>
			<td>575302</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sensimix SYBR Low-ROX kit</td>
			<td>Bioline</td>
			<td>QT625-05</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Transwell permeable supports</td>
			<td>Fisher Scientific</td>
			<td>07-200-170</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypsin-EDTA</td>
			<td>ThermoFisher Scientific- Gibco</td>
			<td>25200056</td>
			<td></td>
		</tr>
	</tbody>
</table>

studying the effects of tumor-secreted paracrine ligands on macrophage activation using co-culture with permeable membrane supports

Tumor-derived paracrine signaling is an overlooked component of local immunosuppression and can lead to a permissive environment for continued cancer growth and metastasis. Paracrine signals can involve cell-cell contact between different cell types, such as PD-L1 expressed on the surface of tumors interacting directly with PD-1 on the surface of T cells, or the secretion of ligands by a tumor cell to affect an immune cell. Here we describe a co-culture method to interrogate the effects of tumor-secreted ligands on immune cell (macrophage) activation. This straightforward procedure utilizes commercially available 0.4 &#181;m polycarbonate membrane permeable supports and standard tissue culture plates. In the process described, macrophages are cultured in the upper chamber and tumor cells in the lower chamber. The presence of the 0.4 &#181;m barrier allows for the study of intercellular signaling without the confounding variable of physical contact, because the two cell types share the same medium and exposure to paracrine ligands. This approach can be combined with others, such as genetic alterations of the macrophage (e.g., isolation from genetic knock-out mice) or tumor (e.g., CRISPR-mediated alterations) to study the role of specific secreted factors and receptors. The approach also lends itself to standard molecular biological analyses such as quantitative reverse transcription polymerase chain reaction (qRT-PCR) or Western blot analysis, without the need for flow sorting to separate the two cell populations. Enzyme-linked immunosorbent assays (ELISAs) can similarly be utilized to measure secreted ligands to better understand the dynamic interaction of cell signaling in the multiple cell type context. Duration of co-culture can also be varied for the study of temporally regulated events. This co-culture method is a robust tool that facilitates the study of tumor-secreted signals in the immune context.

To determine the effect of tumor-secreted ligands on macrophage polarization, the procedure described was utilized. Peritoneal macrophages cultured in the absence of tumor cells were used as negative (untreated = far left) and positive (IFN&#947; and LPS stimulated = 2nd from left) controls (Figure 2A). Alternatively, peritoneal macrophages were co-cultured with B16F10 melanoma tumor cells (ATCC) (Figure 1A). Immediately after plating, cells were eith...

Watch this Scientific Journal Video about Studying the Effects of Tumor-Secreted Paracrine Ligands on Macrophage Activation using Co-Culture with Permeable Membrane Supports at JoVE.com

Studying the Effects of Tumor-Secreted Paracrine Ligands on Macrophage Activation using Co-Culture with Permeable Membrane Supports

Here, we present a method using permeable membrane supports to facilitate the study of non-contact paracrine signaling used by tumor cells to suppress the immune response. The system is amenable to studying the role of tumor-secreted factors in dampening macrophage activation.

Tumor-derived paracrine signaling is an overlooked component of local immunosuppression and can lead to a permissive environment for continued cancer ...

This Transwell co-culture method is used to study paracrine signaling used by tumor cells to suppress the immune response. This method can be used to discover novel secreted ligands, as well as the mechanistic underpinnings of their immune suppressive effects. We have previously used this method to show how tumor-secreted factors can dampen macrophage pro-inflammatory gene transcription.We believe this tool has wide-ranging implications in the study of tumor-derived immune suppression. One of the main advantages of this technique is that it can be used to study paracrine signaling between tumor cells and immune cells without the potentially confounding variable of cell-to-cell contact. This platform is also amenable to a variety of molecular biological techniques for downstream analysis.After harvesting peritoneal macrophages, plate them directly into the upper chambers of a 0.4 micrometer polyester membrane insert co-culture six-well plate. Then added supplemented DMEM to the well such that the top chamber contains one milliliter and the bottom chamber contains 1.5 milliliters. Incubate for three days at 37 degrees Celsius with 5%carbon dioxide.First, culture commercially available tumor cells in their respective medium, following ATCC recommended tissue culture methods. Next, wash the adherent tumor cells once with PBS. Add 0.05%trypsin in EDTA and incubate at 37 degrees Celsius until the cells detach.Then re-suspend the cells in media containing FBS. Use a hemocytometer or cell counter to quantitate the total number of cells and centrifuge at 220 times G for five minutes to pellet. During centrifugation, aspirate the medium from the upper and lower chambers of the macrophage containing permeable membrane support plates and replace with fresh medium.For the lower chambers where tumor cells will be plated, fill with one milliliter of medium instead of 1.5 milliliters to leave sufficient volume for cell addition. When the centrifugation is complete, aspirate the medium from the pelleted tumor cells and re-suspend the cells in supplemented DMEM at a concentration of 300, 000 cells per milliliter. Add 0.5 milliliters of this cell suspension to the lower chamber of the desired wells.To induce macrophage pro-inflammatory gene expression, treat singly or co-cultured macrophages by adding interferon gamma at a concentration of 100 nanograms per milliliter and LPS at a concentration of 50 nanograms per milliliter. Vary the duration of treatment times in culture as needed. Macrophage activation occurs within two hours, and some tumor-mediated suppression occurs by eight hours.Co-culture for 24 hours yields robust and consistent tumor-derived suppression. As a negative control, culture macrophages singly and leave untreated. As a positive control, treat singly-cultured macrophages with interferon gamma and LPS at the same concentrations used for the samples.After the desired incubation time has elapsed, isolate the cell lysate or condition culture medium as desired depending on testing needs. To isolate the cell lysate for quantitative polymerase chain reaction analysis, aspirate the medium from both chambers of the well and wash once with two milliliters of PBS. Apply RNA lysis buffer to the top chamber containing the macrophages.After this, gently scrape the membrane to release the cell lysate and transfer it to a collection tube for further processing according to the RNA isolation kit manufacturer's protocol. The co-culture method described here involves the culture of macrophages and tumor cells without physical contact. Peritoneal macrophages cultured in the absence of tumor cells are used as negative and positive controls.Peritoneal macrophages co-cultured in the presence of B16F10 tumor cells but without activating stimuli do not increase expression of pro-inflammatory associated genes. This implies that tumor-secreted ligands are either not sufficient to induce pro-inflammatory gene expression by themselves, or if there is immune activation by tumor secretions, paracrine ligands are sufficient to suppress it to its native levels. This co-culture method illustrates that when macrophages polarized by interferon gamma and LPS are cultured in the presence of tumor cells, suppression of inflammation-associated gene expression was reduced by as much as 60%A comparable level of macrophage pro-inflammatory gene suppression is observed when the murine macrophage cell line J774 is substituted for peritoneal macrophages.Previous work has identified protein S as a tumor-secreted factor that can inhibit macrophage activation, so the permeable membrane support co-culture model is used in conjunction with a lysA to assay the concentration of protein S in conditioned media after 24 hours. In conditioned media from interferon gamma and LPS-treated B16F10 melanoma cells, protein S is expressed in a concentration of approximately 475 nanograms per milliliter. Peritoneal macrophages treated in the same conditions expressed protein S at approximately 61 nanograms per milliliter.Interestingly, when co-cultured, the concentration of protein S in the interferon gamma and the LPS-treated well was approximately 86 nanograms per milliliter. This suggests that either macrophages ingest tumor-secreted protein S or that the amount of protein S secreted by B16F10 cells is substantially decreased when in the presence of macrophages. These results highlight profound changes of macrophage activation and paracrine signaling when macrophages are co-cultured with tumor cells.The Transwell co-culture method can answer a variety of questions pertaining to paracrine signaling. Western blot analysis could be conducted to determine how tumor-secreted proteins alter various signaling pathways in macrophages.

studying-effects-tumor-secreted-paracrine-ligands-on-macrophage

Research

JoVE Journal

Cancer Research

Characterization of Cell Membrane Extensions and Studying Their Roles in Cancer Cell Adhesion Dynamics

The cell membrane&#39;s extension repertoire modulates various malignant behaviors of cancer cells, including their adhesive and migratory potentials. The ability to accurately classify and quantify cell extensions and measure the effect on a cell&#39;s adhesive capacity is critical to determining how cell-signaling events impact cancer cell behavior and aggressiveness. Here, we describe the in vitro design and use of a cell extension quantification method in conjunction with an adhesion capacity assay in an established in vitro model for adrenocortical carcinoma (ACC). Specifically, we test the effects of DKK3, a putative tumor suppressor and a pro-differentiation factor, on the membrane extension phenotype of the ACC cell line, SW-13. We propose these assays to provide relatively simple, reliable, and easily interpretable metrics to measures these characteristics under various experimental conditions.

This study demonstrates the utility and ease of quantitative cell membrane extension measurement and its correlation to adhesive capacity of cells. As a representative example, we show here that Dickkopf-related protein 3 (DKK3) promotes increased lobopodia formation and cell adhesiveness in adrenocortical carcinoma cells in vitro.

The cell membrane&#39;s extension repertoire modulates various malignant behaviors of cancer cells, including their adhesive and migratory potentials. The ...

Imaging Approaches to Assessments of Toxicological Oxidative Stress Using Genetically-encoded Fluorogenic Sensors

While oxidative stress is a commonly cited toxicological mechanism, conventional methods to study it suffer from a number of shortcomings, including destruction of the sample, introduction of potential artifacts, and a lack of specificity for the reactive species involved. Thus, there is a current need in the field of toxicology for non-destructive, sensitive, and specific methods that can be used to observe and quantify intracellular redox perturbations, more commonly referred to as oxidative stress. Here, we present a method for the use of two genetically-encoded fluorogenic sensors, roGFP2 and HyPer, to be used in live-cell imaging studies to observe xenobiotic-induced oxidative responses. roGFP2 equilibrates with the glutathione redox potential (EGSH), while HyPer directly detects hydrogen peroxide (H2O2). Both sensors can be expressed into various cell types via transfection or transduction, and can be targeted to specific cellular compartments. Most importantly, live-cell microscopy using these sensors offers high spatial and temporal resolution that is not possible using conventional methods. Changes in the fluorescence intensity monitored at 510 nm serves as the readout for both genetically-encoded fluorogenic sensors when sequentially excited by 404 nm and 488 nm light. This property makes both sensors ratiometric, eliminating common microscopy artifacts and correcting for differences in sensor expression between cells. This methodology can be applied across a variety of fluorometric platforms capable of exciting and collecting emissions at the prescribed wavelengths, making it suitable for use with confocal imaging systems, conventional wide-field microscopy, and plate readers. Both genetically-encoded fluorogenic sensors have been used in a variety of cell types and toxicological studies to monitor cellular EGSH and H2O2 generation in real-time. Outlined here is a standardized method that is widely adaptable across cell types and fluorometric platforms for the application of roGFP2 and HyPer in live-cell toxicological assessments of oxidative stress.

This manuscript describes the use of genetically-encoded fluorogenic reporters in an application of live-cell imaging for the examination of xenobiotic-induced oxidative stress. This experimental approach offers unparalleled spatiotemporal resolution, sensitivity, and specificity while avoiding many of the shortcomings of conventional methods used for the detection of toxicological oxidative stress.

While oxidative stress is a commonly cited toxicological mechanism, conventional methods to study it suffer from a number of shortcomings, including ...

Dual Effects of Melanoma Cell-derived Factors on Bone Marrow Adipocytes Differentiation

The crosstalk between bone marrow adipocytes and tumor cells may play a critical role in the process of bone metastasis. A variety of methods are available for studying the significant crosstalk; however, a two-dimensional transwell system for coculture remains a classic, reliable, and easy way for this crosstalk study. Here, we present a detailed protocol that shows the coculture of bone marrow adipocytes and melanoma cells. Nevertheless, such a coculture system could not only contribute to the study of cell signal transductions of cancer cells induced by bone marrow adipocytes, but also to the future mechanistic study of bone metastasis which may reveal new therapeutic targets for bone metastasis.

Here, we present a reliable and straightforward two-dimensional (2D) coculture system for studying the interaction between tumor cells and bone marrow adipocytes, which reveals a dual effect of melanoma cell-derived factors on the bone marrow adipocytes differentiation and also poses a classic method for the mechanistic study of bone metastasis.

The crosstalk between bone marrow adipocytes and tumor cells may play a critical role in the process of bone metastasis. A variety of methods are ...

Mesenchymal Stem Cell Isolation from Pulp Tissue and Co-Culture with Cancer Cells to Study Their Interactions

Cancer as a multistep process and complicated disease is not only regulated by individual cell proliferation and growth but also controlled by tumor environment and cell-cell interactions. Identification of cancer and stem cell interactions, including changes in extracellular environment, physical interactions, and secreted factors, might enable the discovery of new therapy options. We combine known co-culture techniques to create a model system for mesenchymal stem cells (MSCs) and cancer cell interactions. In the current study, dental pulp stem cells (DPSCs) and PC-3 prostate cancer cell interactions were examined by direct and indirect co-culture techniques. Condition medium (CM) obtained from DPSCs and 0.4 &#181;m pore sized trans-well membranes were used to study paracrine activity. Co-culture of different cell types together was performed to study direct cell-cell interaction. The results revealed that CM increased cell proliferation and decreased apoptosis in prostate cancer cell cultures. Both CM and trans-well system increased cell migration capacity of PC-3 cells. Cells stained with different membrane dyes were seeded into the same culture vessels, and DPSCs participated in a self-organized structure with PC-3 cells under this direct co-culture condition. Overall, the results indicated that co-culture techniques could be useful for cancer and MSC interactions as a model system.

We provide protocols for evaluation of mesenchymal stem cells isolated from dental pulp and prostate cancer cell interactions based on direct and indirect co-culture methods. Condition medium and trans-well membranes are suitable to analyze indirect paracrine activity. Seeding differentially stained cells together is an appropriate model for direct cell-cell interaction.

Cancer as a multistep process and complicated disease is not only regulated by individual cell proliferation and growth but also controlled by tumor ...

Measuring Bone Remodeling and Recreating the Tumor-Bone Microenvironment Using Calvaria Co-culture and Histomorphometry

Bone is a connective tissue constituted of osteoblasts, osteocytes, and osteoclasts and a mineralized extracellular matrix, which gives it its strength and flexibility and allows it to fulfill its functions. Bone is continuously exposed to a variety of stimuli, which in pathological conditions can deregulate bone remodeling. To study bone biology and diseases and evaluate potential therapeutic agents, it has been necessary to develop in vitro and in vivo models.
This manuscript describes the dissection process and culture conditions of calvarias isolated from neonatal mice to study bone formation and the bone tumor microenvironment. In contrast to in vitro and in vivo models, this ex vivo model allows preservation of the three-dimensional environment of the tissue as well as the cellular diversity of the bone while culturing under defined conditions to simulate the desired microenvironment. Therefore, it is possible to investigate bone remodeling and its mechanisms, as well as the interactions with other cell types, such as the interactions between cancer cells and bone.
The assays reported here use calvarias from 5-7 day old BALB/C mice. The hemi-calvarias obtained are cultured in the presence of insulin, breast cancer cells (MDA-MB-231), or conditioned medium from breast cancer cell cultures. After analysis, it was established that insulin induced new bone formation, while cancer cells and their conditioned medium induced bone resorption. The calvarial model has been successfully used in basic and applied research to study bone development and cancer-induced bone diseases. Overall, it is an excellent option for an easy, informative, and low-cost assay.

The ex vivo culture of bone explants can be a valuable tool for the study of bone physiology and the potential evaluation of drugs in bone remodeling and bone diseases. The presented protocol describes the preparation and culture of calvarias isolated from newborn mice skulls, as well as its applications.

Bone is a connective tissue constituted of osteoblasts, osteocytes, and osteoclasts and a mineralized extracellular matrix, which gives it its strength ...

Studying Normal Tissue Radiation Effects using Extracellular Matrix Hydrogels

Radiation is a therapy for patients with triple negative breast cancer. The effect of radiation on the extracellular matrix (ECM) of healthy breast tissue and its role in local recurrence at the primary tumor site are unknown. Here we present a method for the decellularization, lyophilization, and fabrication of ECM hydrogels derived from murine mammary fat pads. Results are presented on the effectiveness of the decellularization process, and rheological parameters were assessed. GFP- and luciferase-labeled breast cancer cells encapsulated in the hydrogels demonstrated an increase in proliferation in irradiated hydrogels. Finally, phalloidin conjugate staining was employed to visualize cytoskeleton organization of encapsulated tumor cells. Our goal is to present a method for fabricating hydrogels for in vitro study that mimic the in vivo breast tissue environment and its response to radiation in order to study tumor cell behavior.

This protocol presents a method for decellularization and subsequent hydrogel formation of murine mammary fat pads following ex vivo irradiation.

Radiation is a therapy for patients with triple negative breast cancer. The effect of radiation on the extracellular matrix (ECM) of healthy breast tissue ...

Co-culture of Glioblastoma Stem-like Cells on Patterned Neurons to Study Migration and Cellular Interactions

Glioblastomas (GBMs), grade IV malignant gliomas, are one of the deadliest types of human cancer because of their aggressive characteristics. Despite significant advances in the genetics of these tumors, how GBM cells invade the healthy brain parenchyma is not well understood. Notably, it has been shown that GBM cells invade the peritumoral space via different routes; the main interest of this paper is the route along white matter tracts (WMTs). The interactions of tumor cells with the peritumoral nervous cell components are not well characterized. Herein, a method has been described that evaluates the impact of neurons on GBM cell invasion. This paper presents an advanced co-culture in vitro assay that mimics WMT invasion by analyzing the migration of GBM stem-like cells on neurons. The behavior of GBM cells in the presence of neurons is monitored by using an automated tracking procedure with open-source and free-access software. This method is useful for many applications, in particular, for functional and mechanistic studies as well as for analyzing the effects of pharmacological agents that can block GBM cell migration on neurons.

Here, we present an easy-to-use co-culture assay to analyze glioblastoma (GBM) migration on patterned neurons. We developed a macro in FiJi software for easy quantification of GBM cell migration on neurons, and observed that neurons modify GBM cell invasive capacity.

Glioblastomas (GBMs), grade IV malignant gliomas, are one of the deadliest types of human cancer because of their aggressive characteristics. Despite ...

Modeling the Effects of Hemodynamic Stress on Circulating Tumor Cells using a Syringe and Needle

During metastasis, cancer cells from solid tissues, including epithelia, gain access to the lymphatic and hematogenous circulation where they are exposed to mechanical stress due to hemodynamic flow. One of these stresses that circulating tumor cells (CTCs) experience is fluid shear stress (FSS). While cancer cells may experience low levels of FSS within the tumor due to interstitial flow, CTCs are exposed, without extracellular matrix attachment, to much greater levels of FSS. Physiologically, FSS ranges over 3-4 orders of magnitude, with low levels present in lymphatics (&#60;1 dyne/cm2) and the highest levels present briefly as cells pass through the heart and around heart valves (&#62;500 dynes/cm2). There are a few in vitro models designed to model different ranges of physiological shear stress over various time frames. This paper describes a model to investigate the consequences of brief (millisecond) pulses of high-level FSS on cancer cell biology using a simple syringe and needle system.

Here we demonstrate a method to apply fluid shear stress to cancer cells in suspension to model the effects of hemodynamic stress on circulating tumor cells.

During metastasis, cancer cells from solid tissues, including epithelia, gain access to the lymphatic and hematogenous circulation where they are exposed ...

Co-Culture and Transduction of Murine Thymocytes on Delta-Like 4-Expressing Stromal Cells to Study Oncogenes in T-Cell Leukemia

Transduced mouse immature thymocytes can be differentiated into T cells&#160;in vitro&#160;using the delta-like 4-expressing bone marrow stromal cell line co-culture system (OP9-DL4). As retroviral transduction requires dividing cells for transgene integration, OP9-DL4 provides a suitable in vitro environment for cultivating hematopoietic progenitor cells. This is particularly advantageous when studying the effects of the expression of a specific gene during normal T cell development and leukemogenesis, as it allows researchers to circumvent the time-consuming process of generating transgenic mice. To achieve successful outcomes, a series of coordinated steps involving the simultaneous manipulation of different types of cells must be carefully performed. Although these are very well-established procedures, the lack of a common source in the literature often means a series of optimizations are required, which can be time-consuming. This protocol has been shown to be efficient in transducing primary thymocytes followed by differentiation on OP9-DL4 cells. Detailed here is a protocol that can serve as a quick and optimized guide for the co-culture of retrovirally transduced thymocytes on OP9-DL4 stromal cells.

This protocol describes the isolation of double-negative thymocytes from the mouse thymus followed by retroviral transduction and co-culture on the delta-like 4-expressing bone marrow stromal cell line co-culture system (OP9-DL4) for further functional analysis.

Transduced mouse immature thymocytes can be differentiated into T cells&#160;in vitro&#160;using the delta-like 4-expressing bone marrow stromal cell line ...