This study is funded in part by The Janet Burros Memorial Foundation. We acknowledge the patients and the Karmanos Cancer Institute Gynecologic Oncology Department for the collection of omentum samples. We also acknowledge the Biobank and Correlative Sciences Core at Karmanos Cancer Institute for coordination of patient recruitment and preparation of pathology slides. The Biobank and Correlative Sciences Core is supported in part by NIH Center grant P30 CA22453 to the Karmanos Cancer Institute at Wayne State University.

The following research protocol was reviewed and approved by the Wayne State University Institutional Review Board (IRB). Informed consent was obtained from all patients prior to surgery. Figure 1 illustrates the three general steps in this protocol.
1. Preparation of human omentum tissue
<ol>
	<li>Prepare omentum culture media (DMEM/F12 + 10% fetal bovine serum + 1% penicillin-streptomycin) and store at 4 &#176;C. Aliquot 30-40 mL of this media into a sterile 50 mL conical tube or surgical specimen container.</li>
	<li>Obtain surgical specimens from omental biopsy or omentectomy surgery. Immerse the sterile specimen in omentum culture media immediately after removal in the operating room. If the workflow does not allow this, place the specimen in omentum culture media as soon as possible. Transfer the sample by placing it on ice and store at 4 &#176;C until processing. 
	NOTE: The size of the omentum specimen removed will determine the amount of workable tissue.</li>
	<li>Process the omentum specimen within 1-2 h of collection using a laminar flow hood. Ensure that all materials and tools are sterile or sterilized.</li>
	<li>Remove the omentum from the collection container and transfer it into a 100 mm culture dish. Immerse the specimen in 1x phosphate-buffered saline (1x PBS) and gently wash the specimen to remove any blood clots or debris.</li>
	<li>Cut the tissue into pieces (0.5 cm x 0.5 cm or 100-200 mg; Figure 2A) using either small surgical scissors or a 10-15 mm scalpel. Use small surgical forceps to help manipulate the tissue and avoid crushing the omentum. If an energy device was used to surgically remove the omentum specimen, then avoid using the distorted tissue at the sealed edge.</li>
	<li>Place each piece of cut omentum into individual wells of a 24-well culture plate and fill the wells with 500 &#956;L of omentum culture media or to a volume that is enough to cover the omentum without allowing the omentum piece to float above the well floor (Figure 2B).</li>
	<li>Store omentum pieces in fresh culture media at 4 &#176;C until ready for injection.</li>
</ol>
2. Preparation of ovarian cancer cells
<ol>
	<li>Culture human ovarian cancer cells in a 75 cm2 culture flask at 37 &#176;C and 5% CO2 to at least 75% confluency by the day of omentum collection. 
	NOTE: This protocol utilizes mCherry-positive OCSC1-F2 human ovarian cancer cells previously described15,16,17,18. It can be modified to any cancer cell line tagged with a fluorescence signal.</li>
	<li>Prepare cells inside a laminar flow hood immediately after collection of the omentum specimen. Ensure that all materials and tools are sterile or sterilized.</li>
	<li>Add 10 mL of sterile 1x PBS to the culture flask and wash the cells by gently rocking the flask. Remove the 1x PBS and then add 3 mL of 0.05% Trypsin-EDTA.</li>
	<li>Gently rock the culture flask to coat all cells, and then place the flask in an incubator (37 &#176;C and 5% CO2) for no more than 5 min. Tap the culture flask to completely detach the cells, and then neutralize trypsin by adding 3 mL of omentum culture media.</li>
	<li>Mix the cell suspension by pipetting, and then transfer the suspension into a 15 mL conical tube. Centrifuge the suspension for 5 min at 1,200 x g at 24 &#176;C. Remove the supernatant and resuspend the cell pellet in 6 mL of fresh omentum culture media.</li>
	<li>Count the cells using a hemacytometer. Dilute the cell suspension to at least 100,000 cells per 100-200 &#956;L of suspension. This is the volume of injection into each cut piece of omentum.</li>
	<li>Transfer an appropriate number of cells into a new culture flask to continue cell passage.</li>
</ol>
3. Injection of ovarian cancer cells
<ol>
	<li>Use a 1 mL syringe to draw up the cell suspension, then attach a 26-G needle. Do not draw up the cell suspension using the needle, as this can fragment the cells.</li>
	<li>Use small surgical forceps to pick up a piece of cut omentum. Transfer the omentum to a separate working sterile dish to facilitate injection. Gently pierce the omentum with the needle tip and inject a small volume of cell suspension into the tissue (Figure 2C).</li>
	<li>Repeat injection over several areas of omentum to a total volume of at least 100 &#956;L or 100,000 cells. Note that much of the cell suspension may appear to pool around the specimen. If there is concern regarding the quality of the injection, then repeat the injection or inject a larger volume of cell suspension into the specimen.</li>
	<li>Return the injected omentum samples into each well of a 24-well culture plate. Take note that the volume of omentum culture media is to a level that covers the omentum without allowing it to float. Carefully handle the plate and place it inside an incubator (37 &#176;C and 5% CO2).</li>
	<li>OPTIONAL: Use Matrigel (basement membrane matrix) to suspend omentum tissue in a solid matrix to allow easier injection and more concentrated cell suspension delivery.
	<ol>
		<li>Thaw the basement membrane matrix at 4 &#176;C and mix in 1:1 ratio with omentum culture media immediately prior to use. Store the basement membrane matrix mixture on ice or at 4 &#176;C until injection. Fill empty wells with enough basement membrane matrix mixture to immerse a cut piece of omentum.</li>
		<li>Place specimens into the basement membrane matrix mixture and then place the 24 well culture plate in an incubator (37 &#176;C and 5% CO2) for 20 min. Once the mixture has solidified, continue with injection as described above.</li>
	</ol>
	</li>
	<li>Confirm successful injection using fluorescent imaging. Ensure a streak of fluorescent signal is visualized at the injection sites (Figure 2D). Note that the actual number of cells attached to the omentum after injection is unpredictable.</li>
</ol>
4. Co-culture of human omentum and ovarian cancer cells
<ol>
	<li>Change media every 48-72 h by adding 500-2000 &#956;L of fresh omentum culture media. Do not pipet media directly on top of omentum tissue, as this may displace cancer cells. Note that if the media color turns to yellow, then change the media. 
	NOTE: The frequency of media change will depend on the volume of media used and the trajectory of cancer cell growth. Once the cancer cells have seeded the omentum, whether or not the omentum piece is floating is no longer important.</li>
	<li>OPTIONAL: If a basement membrane matrix was used, the matrix would typically be dissolved by the time of the first media change.</li>
	<li>Monitor the growth of ovarian cancer tumors using fluorescent imaging. Frequency of imaging is at the discretion of the investigator. Anticipate evidence of small tumors by about 14 days (Figure 3A-C). Results may vary depending on the quality of the injection.</li>
	<li>Terminate the experiment based on the experiment endpoint. 
	NOTE: Tumor growth and integrity of omentum tissue have been observed past 50 days.</li>
</ol>

Establishing a 3D Ex Vivo Model for Ovarian Cancer-Omentum Interaction

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	<li>Siegel, R. L., Miller, K. D., Wagle, N. S., Jemal, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+statistics.">Cancer statistics.</a> CA Cancer J Clin. 73 (1), 17-48 (2023).</li><li>Berek, J. S., Renz, M., Kehoe, S., Kumar, L., Friedlander, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+of+the+ovary,+fallopian+tube,+and+peritoneum:+2021+update.">Cancer of the ovary, fallopian tube, and peritoneum: 2021 update.</a> Int J Gynaecol Obstet. 155 (Suppl 1), 61-85 (2021).</li><li>Ledermann, J. 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=Newly+diagnosed+and+relapsed+epithelial+ovarian+carcinoma:+ESMO+clinical+practice+guidelines+for+diagnosis,+treatment+and+follow-up.">Newly diagnosed and relapsed epithelial ovarian carcinoma: ESMO clinical practice guidelines for diagnosis, treatment and follow-up.</a> Ann Oncol. 24 (Suppl 6), vi24-32 (2013).</li><li>Jelovac, D., Armstrong, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progress+in+the+diagnosis+and+treatment+of+ovarian+cancer.">Recent progress in the diagnosis and treatment of ovarian cancer.</a> CA Cancer J Clin. 61 (3), 183-203 (2011).</li><li>Morgan, R. 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=Ovarian+cancer.+Clinical+practice+guidelines+in+oncology.">Ovarian cancer. Clinical practice guidelines in oncology.</a> J Natl Compr Canc Netw. 6 (8), 766-794 (2008).</li><li>Nieman, K. 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=Adipocytes+promote+ovarian+cancer+metastasis+and+provide+energy+for+rapid+tumor+growth.">Adipocytes promote ovarian cancer metastasis and provide energy for rapid tumor growth.</a> Nat Med. 17 (11), 1498-1503 (2011).</li><li>Motohara, 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=An+evolving+story+of+the+metastatic+voyage+of+ovarian+cancer+cells:+cellular+and+molecular+orchestration+of+the+adipose-rich+metastatic+microenvironment.">An evolving story of the metastatic voyage of ovarian cancer cells: cellular and molecular orchestration of the adipose-rich metastatic microenvironment.</a> Oncogene. 38 (16), 2885-2898 (2019).</li><li>Di Nicola, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Omentum+a+powerful+biological+source+in+regenerative+surgery.">Omentum a powerful biological source in regenerative surgery.</a> Regen Ther. 11, 182-191 (2019).</li><li>Meza-Perez, S., Randall, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunological+functions+of+the+omentum.">Immunological functions of the omentum.</a> Trends Immunol. 38 (7), 526-536 (2017).</li><li>Liu, M., Silva-Sanchez, A., Randall, T. D., Meza-Perez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specialized+immune+responses+in+the+peritoneal+cavity+and+omentum.">Specialized immune responses in the peritoneal cavity and omentum.</a> J Leukoc Biol. 109 (4), 717-729 (2021).</li><li>Lee, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutrophils+facilitate+ovarian+cancer+premetastatic+niche+formation+in+the+omentum.">Neutrophils facilitate ovarian cancer premetastatic niche formation in the omentum.</a> J Exp Med. 216 (1), 176-194 (2019).</li><li>Cardenas, C., 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=Adipocyte+microenvironment+promotes+Bclxl+expression+and+confers+chemoresistance+in+ovarian+cancer+cells.">Adipocyte microenvironment promotes Bclxl expression and confers chemoresistance in ovarian cancer cells.</a> Apoptosis. 22 (4), 558-569 (2017).</li><li>Wu, Q., 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=Cancer-associated+adipocytes:+key+players+in+breast+cancer+progression.">Cancer-associated adipocytes: key players in breast cancer progression.</a> J Hematol Oncol. 12 (1), 95 (2019).</li><li>Zhang, Z., Scherer, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue:+The+dysfunctional+adipocyte+-+a+cancer+cell's+best+friend.">Adipose tissue: The dysfunctional adipocyte - a cancer cell's best friend.</a> Nat Rev Endocrinol. 14 (3), 132-134 (2018).</li><li>Alvero, A. B., 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=TRX-E-002-1+Induces+c-Jun-dependent+apoptosis+in+ovarian+cancer+stem+cells+and+prevents+recurrence+in+vivo.">TRX-E-002-1 Induces c-Jun-dependent apoptosis in ovarian cancer stem cells and prevents recurrence in vivo.</a> Mol Cancer Ther. 15 (6), 1279-1290 (2016).</li><li>Alvero, A. 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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=Murine+model+for+non-invasive+imaging+to+detect+and+monitor+ovarian+cancer+recurrence.">Murine model for non-invasive imaging to detect and monitor ovarian cancer recurrence.</a> J Vis Exp. (93), e51815 (2014).</li><li>Agarwal, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage+migration+inhibitory+factor+expression+in+ovarian+cancer.">Macrophage migration inhibitory factor expression in ovarian cancer.</a> Am J Obstet Gynecol. 196 (4), 348.e1-348.e5 (2007).</li><li>Kelly, M. G., 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=TLR-4+signaling+promotes+tumor+growth+and+paclitaxel+chemoresistance+in+ovarian+cancer.">TLR-4 signaling promotes tumor growth and paclitaxel chemoresistance in ovarian cancer.</a> Cancer Res. 66 (7), 3859-3868 (2006).</li><li>Li, 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=CBX7+binds+the+E-box+to+inhibit+TWIST-1+function+and+inhibit+tumorigenicity+and+metastatic+potential.">CBX7 binds the E-box to inhibit TWIST-1 function and inhibit tumorigenicity and metastatic potential.</a> Oncogene. 39 (20), 3965-3979 (2020).</li><li>Tedja, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+stable+epithelial-mesenchymal+hybrid+cancer+cells+with+tumorigenic+potential.">Generation of stable epithelial-mesenchymal hybrid cancer cells with tumorigenic potential.</a> Cancers (Basel). 15 (3), 15030684 (2023).</li><li>Dauleh, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterisation+of+cultured+mesothelial+cells+derived+from+the+murine+adult+omentum.">Characterisation of cultured mesothelial cells derived from the murine adult omentum.</a> PLoS One. 11 (7), e0158997 (2016).</li></ol>

The authors have nothing to disclose.

Using this protocol, a preclinical model of peritoneal carcinomatosis for ovarian cancer was developed using a combination of basic in vitro and ex vivo techniques. A progressive tumor growth was observed across 50 days of co-culture after seeding omentum specimens with mCherry+ OCSC1-F2 human ovarian cancer cells. This method was developed and optimized across several experimental trials using different omentum specimens. Successful tumor growth depended on the quality of omentum, viability of cancer c...

Ovarian cancer is the deadliest gynecologic malignancy worldwide1. The lifetime risk of developing this cancer is approximately 1 in 70, with the median age of diagnosis at 63 years old2. Primary ovarian malignancies are classified histologically as either epithelial or non-epithelial. Epithelial ovarian cancers (EOC) represent over 90% of tumors, and the most common subtype is high-grade serous carcinoma (HGSC), which accounts for approximately 70%-80% of EOCs. Currently, there are no effective screening methods to detect disease early. So most patients are diagnosed at an advanced stage (i.e., F&#233;d&#233;ration Internationale de Gyn&#233;cologie et d&#39;Obst&#233;trique [FIGO] stage III or IV) after the cancer has spread throughout the peritoneal cavity2.
Standard frontline treatment is cytoreductive surgery to remove all visible macroscopic disease, followed by adjuvant platinum-based chemotherapy to destroy any residual microscopic disease. While there have been many advances in ovarian cancer treatment over the last two decades, approximately 70% of patients with advanced disease will relapse within 3 years of treatment3. Given the overall poor prognosis of these patients, ongoing and future translational research efforts in EOC aim to identify biomarkers for early detection, prevent metastasis, improve current therapies to evade resistance and develop new personalized cancer treatments.
Generalized metastasis within the peritoneal cavity and its associated chemoresistance are two of the major limitations for the improvement of the treatment of patients with ovarian cancer4,5. The omentum, a fatty apron-like structure that hangs down from the stomach over the intestines, is a main site of ovarian cancer metastasis6,7. In addition to its function as a physical barrier, the omentum has been shown to have regenerative and angiogenic capacities and possess immune activities, which together promote vascularization, accelerate wound healing, and limit infection8. It contains a high concentration of stem cells that can differentiate into various cell types and can help repair damaged tissues. The omentum can become inflamed in response to injury or infection, which triggers the migration of immune cells to the site of injury9. These immune cells release growth factors and other molecules that help to promote the repair and regeneration of damaged tissue. Immune cells, such as macrophages, lymphocytes, and plasma cells, localized in the omentum are structures known as &#34;milky spots&#34;, which are responsible for detecting and attacking pathogens and regulating peritoneal immunity. The omentum has also been shown to play a role in inducing immune tolerance10, which is the ability of the immune system to tolerate self-antigens and not attack healthy tissues. However, the same immune-related activities are also involved in pathological responses, such as the growth of omental tumors, metastasis, and escape of immune surveillance9,11. Previous studies from our lab and others have demonstrated a unique and active role of the adipose microenvironment in the inhibition of anti-tumoral immune responses and in the acquisition of chemoresistance12,13,14. Unfortunately, we have limited information on the cellular and molecular mechanisms by which the omentum provides a pro-tumoral microenvironment.
To better understand the interactions between cancer cells and the omentum, a 3D culture system consisting of human ovarian cancer cells and patient-derived omentum explants was developed. The protocol described here represents a novel ex vivo model of peritoneal carcinomatosis. This model mimics the natural progression of ovarian cancer tumorigenesis in this adipose-rich tissue. The proposed model is easy to generate, inexpensive, and potentially applicable to translational investigations in ovarian cancer research.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.05% Trypsin-EDTA (1x)</td>
			<td>Gibco</td>
			<td>25300054</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Insulin Syringe with 26 G detachable needle</td>
			<td>BD</td>
			<td>329652</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL Serological Pipets</td>
			<td>CELLTREAT</td>
			<td>229010B</td>
			<td></td>
		</tr>
		<tr>
			<td>100 mm Tissue Culture Dish</td>
			<td>Fisherbrand</td>
			<td>FB012924</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL Centrifuge Tube</td>
			<td>CELLTREAT</td>
			<td>229411</td>
			<td></td>
		</tr>
		<tr>
			<td>24 Well Cell Culture Plate</td>
			<td>Costar</td>
			<td>3524</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Centrifuge Tube</td>
			<td>CELLTREAT</td>
			<td>229421</td>
			<td></td>
		</tr>
		<tr>
			<td>75 cm2 Tissue Culture Flask</td>
			<td>CELLTREAT</td>
			<td>229341</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning Cell Counter</td>
			<td>Corning</td>
			<td>9819000</td>
			<td></td>
		</tr>
		<tr>
			<td>Cytation 5 imager</td>
			<td>Biotek</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12 (1:1) (1x), +L-Glutamine, +2.438 g/L Sodium Bicarbonate</td>
			<td>Gibco</td>
			<td>11320033</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, Qualified</td>
			<td>Gibco</td>
			<td>1043028</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>Corning</td>
			<td>356230</td>
			<td>Basement membrane matrix</td>
		</tr>
		<tr>
			<td>No. 10 Stainless Steel Disposable Scalpel</td>
			<td>Integra-Miltex</td>
			<td>4410</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin Streptomycin</td>
			<td>Gibco</td>
			<td>15140122</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline, pH 7.4 (1x)</td>
			<td>Gibco</td>
			<td>10010023</td>
			<td></td>
		</tr>
		<tr>
			<td>Revolve microscope</td>
			<td>Echo</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

an ex vivo model of ovarian cancer peritoneal metastasis using human omentum

Ovarian cancer is the deadliest gynecologic malignancy. The omentum plays a key role in providing a supportive microenvironment to metastatic ovarian cancer cells as well as immune modulatory signals that allow tumor tolerance. However, we have limited models that closely mimic the interaction between ovarian cancer cells and adipose-rich tissues. To further understand the cellular and molecular mechanisms by which the omentum provides a pro-tumoral microenvironment, we developed a unique 3D ex vivo model of cancer cell-omentum interaction. Using human omentum, we are able to grow ovarian cancer cells within this adipose-rich microenvironment and monitor the factors responsible for tumor growth and immune regulation. In addition to providing a platform for the study of this adipose-rich tumor microenvironment, the model provides an excellent platform for the development and evaluation of novel therapeutic approaches to target metastatic cancer cells in this niche. The proposed model is easy to generate, inexpensive, and applicable to translational investigations.

Successful establishment of ovarian cancer cells into omentum specimens was evident by about day 14 (Figure 3A-C). At least 24 replicates were prepared and injected per collected specimen to allow for further experimentation. Tumor growth was monitored by taking fluorescent images (Figure 3D,E). Images had to be carefully interpreted as a monolayer of cancer cells also grew at the bottom of each well that was no...

Watch this Scientific Journal Video about Advanced Ex Vivo Model for Investigating Cancer-Adipose Microenvironment Interaction at JoVE.com

Author Spotlight: Advanced Ex Vivo Model for Investigating Cancer-Adipose Microenvironment Interaction 

This protocol describes the establishment of a three-dimensional (3D) ex vivo model of cancer cell-omentum interaction. The model provides a platform for elucidating pro-tumor mechanisms within the adipose niche and for testing novel therapies.

An Ex Vivo Model of Ovarian Cancer Peritoneal Metastasis Using Human Omentum

Ovarian cancer is the deadliest gynecologic malignancy. The omentum plays a key role in providing a supportive microenvironment to metastatic ovarian ...

Current studies use co-culture systems comprised of isolated adipocytes and ovarian cancer cells. These adipocytes are differentiated in vitro from pre adipocytes. These cells are then separated through a transwell insert and therefore lack direct cell to cell contact.This ex vivo culture method offers a model to study the direct interaction of cancer cells with the adipose microenvironment. Our model preserves the structure of the human momentum and therefore maintains the various cell types that are typically in this organ. In addition to adipocytes, these cells include supporting fibroblasts as well as immune cells.This model also maintains these cells in their inherent matrix. This model provides an excellent platform for the development and evaluation of novel therapeutic approaches to target metastatic cancer cells in this niche.

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2.4K Views.  Karmanos Cancer Institute. Current studies use co-culture systems comprised of isolated adipocytes and ovarian cancer cells. These adipocytes are differentiated in vitro from pre adipocytes. These cells are then separated through a transwell insert and therefore lack direct cell to cell contact.This ex vivo culture method offers a model to study the direct interaction of cancer cells with the adipose microenvironment. Our model preserves the structure of the human momentum and therefore maintains the various cel...

Video: Author Spotlight: Advanced Ex Vivo Model for Investigating Cancer-Adipose Microenvironment Interaction 

Murine Experimental Model of Original Tumor Development and Peritoneal Metastasis via Orthotopic Inoculation with Ovarian Carcinoma Cells

Epithelial ovarian carcinoma (EOC) is associated with a poor prognosis because it shows peritoneal dissemination. To improve the prognosis, it is important to control peritoneal dissemination. However, it is still unclear how tumor cells detach from primary lesions and attach to the mesothelium. The establishment of an appropriate animal model is needed to gain an understanding of the mechanism of peritoneal dissemination in vivo. In the current study, we introduce the process from the local injection of EOC cells into the murine ovarian surface to the development of metastasis, including the peritoneum and distant organs. Female nude mice (BALB/c nu/nu) at 8 weeks of age were used. Under a microscopic field of view, EOC cells (1 x 105 cells/&#181;l of medium-extracellular matrix (ECM)-based hydrogel/unilateral ovary/mouse) were injected into murine ovaries through a retroperitoneal approach from the dorsal flank. This proposed method is a less invasive procedure for the mouse and minimizes damage to the ovary. Here, we describe the methodological steps in the development of the original and metastatic tumor formation of EOC.

Murine Experimental Model of Original Tumor Development and Peritoneal Metastasis via Orthotopic Inoculation with Ovarian Carcinoma Cells

To clarify the multistep process of peritoneal dissemination of ovarian carcinoma, the current study presents a murine experimental model of original tumor development and peritoneal metastasis via orthotopic inoculation with these tumor cells.

Epithelial ovarian carcinoma (EOC) is associated with a poor prognosis because it shows peritoneal dissemination. To improve the prognosis, it is ...

In Vivo Model for Testing Effect of Hypoxia on Tumor Metastasis

Hypoxia has been implicated in the metastasis of Ewing sarcoma (ES) by clinical observations and in vitro data, yet direct evidence for its pro-metastatic effect is lacking and the exact mechanisms of its action are unclear. Here, we report an animal model that allows for direct testing of the effects of tumor hypoxia on ES dissemination and investigation into the underlying pathways involved. This approach combines two well-established experimental strategies, orthotopic xenografting of ES cells and femoral artery ligation (FAL), which induces hindlimb ischemia. Human ES cells were injected into the gastrocnemius muscles of SCID/beige mice and the primary tumors were allowed to grow to a size of 250 mm3. At this stage either the tumors were excised (control group) or the animals were subjected to FAL to create tumor hypoxia, followed by tumor excision 3 days later. The efficiency of FAL was confirmed by a significant increase in binding of hypoxyprobe-1 in the tumor tissue, severe tumor necrosis and complete inhibition of primary tumor growth. Importantly, despite these direct effects of ischemia, an enhanced dissemination of tumor cells from the hypoxic tumors was observed. This experimental strategy enables comparative analysis of the metastatic properties of primary tumors of the same size, yet significantly different levels of hypoxia. It also provides a new platform to further assess the mechanistic basis for the hypoxia-induced alterations that occur during metastatic tumor progression in vivo. In addition, while this model was established using ES cells, we anticipate that this experimental strategy can be used to test the effect of hypoxia in other sarcomas, as well as tumors orthotopically implanted in sites with a well-defined blood supply route.

In Vivo Model for Testing Effect of Hypoxia on Tumor Metastasis

This manuscript describes the development of an animal model that allows for the direct testing of the effects of tumor hypoxia on metastasis and the deciphering the mechanisms of its action. Although the experiments described here focus on Ewing sarcoma, a similar approach can be applied to other tumor types.

Hypoxia has been implicated in the metastasis of Ewing sarcoma (ES) by clinical observations and in vitro data, yet direct evidence for its pro-metastatic ...

A Portal Vein Injection Model to Study Liver Metastasis of Breast Cancer

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Liver metastasis is involved in upwards of 30% of cases with breast cancer metastasis, and results in poor outcomes with median survival rates of only 4.8 - 15 months. Current rodent models of breast cancer metastasis, including primary tumor cell xenograft and spontaneous tumor models, rarely metastasize to the liver. Intracardiac and intrasplenic injection models do result in liver metastases, however these models can be confounded by concomitant secondary-site metastasis, or by compromised immunity due to removal of the spleen to avoid tumor growth at the injection site. To address the need for improved liver metastasis models, a murine portal vein injection method that delivers tumor cells firstly and directly to the liver was developed. This model delivers tumor cells to the liver without complications of concurrent metastases in other organs or removal of the spleen. The optimized portal vein protocol employs small injection volumes of 5 - 10 &#956;l, &#8805; 32 gauge needles, and hemostatic gauze at the injection site to control for blood loss. The portal vein injection approach in Balb/c female mice using three syngeneic mammary tumor lines of varying metastatic potential was tested; high-metastatic 4T1 cells, moderate-metastatic D2A1 cells, and low-metastatic D2.OR cells. Concentrations of &#8804; 10,000 cells/injection results in a latency of ~ 20 - 40 days for development of liver metastases with the higher metastatic 4T1 and D2A1 lines, and &#62; 55 days for the less aggressive D2.OR line. This model represents an important tool to study breast cancer metastasis to the liver, and may be applicable to other cancers that frequently metastasize to the liver including colorectal and pancreatic adenocarcinomas.

A surgical procedure was developed to deliver mammary tumor cells to the murine liver via portal vein injection. This model permits investigation of late stages of liver metastasis in a fully immune competent host, including tumor cell extravasation, seeding, survival, and metastatic outgrowth in the liver.

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Liver metastasis is involved in upwards of 30% of cases with breast ...

Ex Vivo Imaging of Resident CD8 T Lymphocytes in Human Lung Tumor Slices Using Confocal Microscopy

CD8 T cell are key players in the fight against cancer. In order for CD8 T cells to kill tumor cells they need to enter into the tumor, migrate within the tumor microenvironment and respond adequately to tumor antigens. The recent development of improved imaging approaches, such as 2-photon microscopy, and the use of powerful mouse tumor models have shed light on some of the mechanisms that regulate anti-tumor T cell activities. Whereas such systems have provided valuable insights, they do not always predict human responses. In human, our knowledge in the field mainly comes from a description of fixed tumor samples from human patients, as well as in vitro studies. However, in vitro models lack the complex three-dimensional tumor milieu and, therefore, are incomplete approximations of in vivo T cell activities. Fresh slices made from explanted tissue represent a complex multi-cellular tumor environment that can act as an important link between co-cultured studies and animal models. Originally set up in murine lymph nodes1 and previously described in a JoVE article2, this approach has now been transposed to human tumors to examine the dynamics of both plated3&#160;as well as resident&#160;T cells4.
Here, a protocol for the preparation of human lung tumor slices, immunostaining of resident CD8 T and tumor cells, and tracking of CD8 T lymphocytes within the tumor microenvironment using confocal microscopy is described. This system is uniquely placed to screen for novel immunotherapy agents favoring T cell migration in tumors.

Ex Vivo Imaging of Resident CD8 T Lymphocytes in Human Lung Tumor Slices Using Confocal Microscopy

This protocol describes a method to image resident tumor-infiltrating CD8 T cells labeled with fluorescently coupled antibodies within human lung tumor slices. This technique permits real-time analyses of CD8 T cell migration using confocal microscopy.

CD8 T cell are key players in the fight against cancer. In order for CD8 T cells to kill tumor cells they need to enter into the tumor, migrate within the ...

An In Vivo Murine Sciatic Nerve Model of Perineural Invasion

Cancer cells invade nerves through a process termed perineural invasion (PNI), in which cancer cells proliferate and migrate in the nerve microenvironment. This type of invasion is exhibited by a variety of cancer types, and very frequently is found in pancreatic cancer. The microscopic size of nerve fibers within mouse pancreas renders the study of PNI difficult in orthotopic murine models. Here, we describe a heterotopic in vivo model of PNI, where we inject syngeneic pancreatic cancer cell line Panc02-H7 into the murine sciatic nerve. In this model, sciatic nerves of anesthetized mice are exposed and injected with cancer cells. The cancer cells invade in the nerves proximally toward the spinal cord from the point of injection. The invaded sciatic nerves are then extracted and processed with OCT for frozen sectioning. H&amp;E and immunofluorescence staining of these sections allow quantification of both the degree of invasion and changes in protein expression. This model can be applied to a variety of studies on PNI given its versatility. Using mice with different genetic modifications and/or different types of cancer cells allows for investigation of the cellular and molecular mechanisms of PNI and for different cancer types. Furthermore, the effects of therapeutic agents on nerve invasion can be studied by applying treatment to these mice.

An In Vivo Murine Sciatic Nerve Model of Perineural Invasion

We describe an in vivo murine model of perineural invasion by injecting syngeneic pancreatic cancer cells into the sciatic nerve. The model allows for quantification of the extent of nerve invasion, and supports investigation of the cellular and molecular mechanisms of perineural invasion.

Cancer cells invade nerves through a process termed perineural invasion (PNI), in which cancer cells proliferate and migrate in the nerve ...

Zebrafish Model of Neuroblastoma Metastasis

Zebrafish has emerged as an important animal model to study human diseases, especially cancer. Along with the robust transgenic and genome editing technologies applied in zebrafish modeling, the ease of maintenance, high-yield productivity, and powerful live imaging altogether make the zebrafish a valuable model system to study metastasis and cellular and molecular bases underlying this process in vivo. The first zebrafish neuroblastoma (NB) model of metastasis was developed by overexpressing two oncogenes, MYCN and LMO1, under control of the dopamine-beta-hydroxylase (d&#946;h) promoter. Co-overexpressed MYCN and LMO1 led to the reduced latency and increased penetrance of neuroblastomagenesis, as well as accelerated distant metastasis of tumor cells. This new model reliably reiterates many key features of human metastatic NB, including involvement of clinically relevant and metastasis-associated genetic alterations; natural and spontaneous development of metastasis in vivo; and conserved sites of metastases. Therefore, the zebrafish model possesses unique advantages to dissect the complex process of tumor metastasis in vivo.

This paper introduces the method of developing, characterizing, and tracking in real-time the tumor metastasis in zebrafish model of neuroblastoma, specifically in the transgenic zebrafish line with overexpression of MYCN and LMO1, which develops metastasis spontaneously.

Zebrafish has emerged as an important animal model to study human diseases, especially cancer. Along with the robust transgenic and genome editing ...

An Ex Vivo Brain Slice Model to Study and Target Breast Cancer Brain Metastatic Tumor Growth

Brain metastasis is a serious consequence of breast cancer for women as these tumors are difficult to treat and are associated with poor clinical outcomes. Preclinical mouse models of breast cancer brain metastatic (BCBM) growth are useful but are expensive, and it is difficult to track live cells and tumor cell invasion within the brain parenchyma. Presented here is a protocol for ex vivo brain slice cultures from xenografted mice containing intracranially injected breast cancer brain-seeking clonal sublines. MDA-MB-231BR luciferase tagged cells were injected intracranially into the brains of Nu/Nu female mice, and following tumor formation, the brains were isolated, sliced, and cultured ex vivo. The tumor slices were imaged to identify tumor cells expressing luciferase and monitor their proliferation and invasion in the brain parenchyma for up to 10 days. Further, the protocol describes the use of time-lapse microscopy to image the growth and invasive behavior of the tumor cells following treatment with ionizing radiation or chemotherapy. The response of tumor cells to treatments can be visualized by live-imaging microscopy, measuring bioluminescence intensity, and performing histology on the brain slice containing BCBM cells. Thus, this ex vivo slice model may be a useful platform for rapid testing of novel therapeutic agents alone or in combination with radiation to identify drugs personalized to target an individual patient&#39;s breast cancer brain metastatic growth within the brain microenvironment.

An Ex Vivo Brain Slice Model to Study and Target Breast Cancer Brain Metastatic Tumor Growth

We introduce a protocol for measuring real-time drug and radiation response of breast cancer brain metastatic cells in an organotypic brain slice model. The methods provide a quantitative assay to investigate the therapeutic effects of various treatments on brain metastases from breast cancer in an ex vivo manner within the brain microenvironment interface.

Brain metastasis is a serious consequence of breast cancer for women as these tumors are difficult to treat and are associated with poor clinical ...

Maintaining Human Glioblastoma Cellular Diversity Ex vivo using Three-Dimensional Organoid Culture

Glioblastoma (GBM) is the most commonly occurring primary malignant brain cancer with an extremely poor prognosis. Intra-tumoral cellular and molecular diversity, as well as complex interactions between tumor microenvironments, can make finding effective treatments a challenge. Traditional adherent or sphere culture methods can mask such complexities, whereas three-dimensional organoid culture can recapitulate regional microenvironmental gradients. Organoids are a method of three-dimensional GBM culture that better mimics patient tumor architecture, contains phenotypically diverse cell populations, and can be used for medium-throughput experiments. Although three-dimensional organoid culture is more laborious and time-consuming compared to traditional culture, it offers unique benefits and can serve to bridge the gap between current in vitro and in vivo systems. Organoids have established themselves as invaluable tools in the arsenal of cancer biologists to better understand tumor behavior and mechanisms of resistance, and their applications only continue to grow. Here, details are provided about methods for generating and maintaining GBM organoids. Instructions of how to perform organoid sample embedding and sectioning using both frozen and paraffin-embedding techniques, as well as recommendations for immunohistochemistry and immunofluorescence protocols on organoid sections, and measurement of total organoid cell viability, are all also described.

Maintaining Human Glioblastoma Cellular Diversity Ex vivo using Three-Dimensional Organoid Culture

Here, we describe a method of generating glioblastoma (GBM) organoids from primary patient specimens or patient-derived cell cultures and maintaining them to maturity. These GBM organoids contain phenotypically diverse cell populations and recreate tumor microenvironments ex vivo.

Glioblastoma (GBM) is the most commonly occurring primary malignant brain cancer with an extremely poor prognosis. Intra-tumoral cellular and molecular ...

Ex Vivo Organoid Model of Adenovirus-Cre Mediated Gene Deletions in Mouse Urothelial Cells

Bladder cancer is an understudied area, particularly in genetically engineered mouse models (GEMMs). Inbred GEMMs with tissue-specific Cre and loxP sites have been the gold standards for conditional or inducible gene targeting. To provide faster and more efficient experimental models, an ex vivo organoid culture system is developed using adenovirus Cre and normal urothelial cells carrying multiple loxP alleles of the tumor suppressors Trp53, Pten, and Rb1. Normal urothelial cells are enzymatically disassociated from four bladders of triple floxed mice (Trp53f/f: Ptenf/f: Rb1f/f). The urothelial cells are transduced ex vivo with adenovirus-Cre driven by a CMV promoter (Ad5CMVCre). The transduced bladder organoids are cultured, propagated, and characterized in vitro and in vivo. PCR is used to confirm gene deletions in Trp53, Pten, and Rb1. Immunofluorescence (IF) staining of organoids demonstrates positive expression of urothelial lineage markers (CK5 and p63). The organoids are injected subcutaneously into host mice for tumor expansion and serial passages. The immunohistochemistry (IHC) of xenografts exhibits positive expression of CK7, CK5, and p63 and negative expression of CK8 and Uroplakin 3. In summary, adenovirus-mediated gene deletion from mouse urothelial cells engineered with loxP sites is an efficient method to rapidly test the tumorigenic potential of defined genetic alterations.

Ex Vivo Organoid Model of Adenovirus-Cre Mediated Gene Deletions in Mouse Urothelial Cells

This protocol describes the process of the generation and characterization of mouse urothelial organoids harboring deletions in genes of interest. The methods include harvesting mouse urothelial cells, ex vivo transduction with adenovirus driving Cre expression with a CMV promoter, and in vitro as well as in vivo characterization.

Bladder cancer is an understudied area, particularly in genetically engineered mouse models (GEMMs). Inbred GEMMs with tissue-specific Cre and loxP sites ...

Intra-Cardiac Injection of Human Prostate Cancer Cells to Create a Bone Metastasis Xenograft Mouse Model

As the most common male malignancy, prostate cancer (PC) ranks second in mortality, primarily due to a 65%-75% bone metastasis rate. Therefore, it is essential to understand the process and related mechanisms of prostate cancer bone metastasis for developing new therapeutics. For this, an animal model of bone metastasis is an essential tool. Here, we report detailed procedures to generate a bone metastasis mouse model via intra-cardiac injection of prostate cancer cells. A bioluminescence imaging system can determine whether prostate cancer cells have been accurately injected into the heart and monitor cancer cell metastasis since it has great advantages in monitoring metastatic lesion development. This model replicates the natural development of disseminated cancer cells to form micro-metastases in the bone and imitates the pathological process of prostate cancer bone metastasis. It provides an effective tool for further exploration of the molecular mechanisms and the in vivo therapeutic effects of this disease.

Here, we present a protocol for the intra-cardiac injection of human prostate cancer cells to generate a mouse model with bone metastasis lesions.

As the most common male malignancy, prostate cancer (PC) ranks second in mortality, primarily due to a 65%-75% bone metastasis rate. Therefore, it is ...