The authors wish to thank Dr. Fuyuhiko Tamanoi and Binh Vu for the initial training on this method. Discussions with Dr. Eva Koziolek have been instrumental in optimizing this approach and have been very much appreciated. This work would not have been possible without funding from the following sources: the Tobacco-Related Disease Research Program Postdoctoral Fellowship (27FT-0023, to ACS), the Department of Defense (DoD) Ovarian Cancer Research Program (W81XWH-17-1-0160), NCI/NIH (1R21CA216770), Tobacco-Related Disease Research Program High Impact Pilot Award (27IR-0016), and UCLA institutional support, including a JCCC Seed Grant (NCI/NIH P30CA016042) and a 3R Grant from Office of the Vice Chancellor for Research to LW.

<ol>
	<li>Kersten, K., de Visser, K. E., van Miltenburg, M. H., Jonkers, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetically+engineered+mouse+models+in+oncology+research+and+cancer+medicine.">Genetically engineered mouse models in oncology research and cancer medicine.</a> EMBO Molecular Medicine. 9 (2), 137-153 (2017).</li><li>Jackson, S. J., Thomas, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+tissue+models+in+cancer+research:+looking+beyond+the+mouse.">Human tissue models in cancer research: looking beyond the mouse.</a> Disease Models &amp; Mechanisms. 10 (8), 939-942 (2017).</li><li>Cheon, D. J., Orsulic, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+Models+of+Cancer.">Mouse Models of Cancer.</a> Annual Review of Pathology: Mechanisms of Disease. 6 (1), 95-119 (2011).</li><li>. SEER Cancer Statistics Review, 1975-2016 Available from: <a target="_blank" href="https://seer.cancer.gov/csr/1975_2016/">https://seer.cancer.gov/csr/1975_2016/</a> (2018)</li><li>Ribatti, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chicken+chorioallantoic+membrane+angiogenesis+model.">Chicken chorioallantoic membrane angiogenesis model.</a> Methods Molecular Biology. 843, 47-57 (2012).</li><li>Nowak-Sliwinska, P., Segura, T., Iruela-Arispe, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chicken+chorioallantoic+membrane+model+in+biology,+medicine+and+bioengineering.">The chicken chorioallantoic membrane model in biology, medicine and bioengineering.</a> Angiogenesis. 17 (4), 779-804 (2014).</li><li>Lokman, N. A., Elder, A. S., Ricciardelli, C., Oehler, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chick+chorioallantoic+membrane+(CAM)+assay+as+an+in+vivo+model+to+study+the+effect+of+newly+identified+molecules+on+ovarian+cancer+invasion+and+metastasis.">Chick chorioallantoic membrane (CAM) assay as an in vivo model to study the effect of newly identified molecules on ovarian cancer invasion and metastasis.</a> International Journal of Molecular Science. 13 (8), 9959-9970 (2012).</li><li>Xiao, X., 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=Chick+Chorioallantoic+Membrane+Assay:+A+3D+Animal+Model+for+Study+of+Human+Nasopharyngeal+Carcinoma.">Chick Chorioallantoic Membrane Assay: A 3D Animal Model for Study of Human Nasopharyngeal Carcinoma.</a> PLoS ONE. 10 (6), e0130935 (2015).</li><li>Deryugina, E. I., Quigley, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chick+embryo+chorioallantoic+membrane+model+systems+to+study+and+visualize+human+tumor+cell+metastasis.">Chick embryo chorioallantoic membrane model systems to study and visualize human tumor cell metastasis.</a> Histochemistry and Cell Biology. 130 (6), 1119-1130 (2008).</li><li>Shoin, K., 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=Chick+Embryo+Assay+as+Chemosensitivity+Test+for+Malignant+Glioma.">Chick Embryo Assay as Chemosensitivity Test for Malignant Glioma.</a> Japanese Journal of Cancer Research. 82 (10), 1165-1170 (1991).</li><li>Hagedorn, 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=Accessing+key+steps+of+human+tumor+progression+in+vivo+by+using+an+avian+embryo+model.">Accessing key steps of human tumor progression in vivo by using an avian embryo model.</a> Proceedings of the National Academy of Science U S A. 102 (5), 1643-1648 (2005).</li><li>Kavaliauskait&#279;, D., 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=The+Effect+of+Sodium+Valproate+on+the+Glioblastoma+U87+Cell+Line+Tumor+Development+on+the+Chicken+Embryo+Chorioallantoic+Membrane+and+on+EZH2+and+p53+Expression.">The Effect of Sodium Valproate on the Glioblastoma U87 Cell Line Tumor Development on the Chicken Embryo Chorioallantoic Membrane and on EZH2 and p53 Expression.</a> BioMed Research International. 2017, 12 (2017).</li><li>Liu, 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=The+Histone+Methyltransferase+EZH2+Mediates+Tumor+Progression+on+the+Chick+Chorioallantoic+Membrane+Assay,+a+Novel+Model+of+Head+and+Neck+Squamous+Cell+Carcinoma.">The Histone Methyltransferase EZH2 Mediates Tumor Progression on the Chick Chorioallantoic Membrane Assay, a Novel Model of Head and Neck Squamous Cell Carcinoma.</a> Translational Oncology. 6 (3), 273-281 (2013).</li><li>Rudy, S. F., 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=In+vivo+Wnt+pathway+inhibition+of+human+squamous+cell+carcinoma+growth+and+metastasis+in+the+chick+chorioallantoic+model.">In vivo Wnt pathway inhibition of human squamous cell carcinoma growth and metastasis in the chick chorioallantoic model.</a> Journal of Otolaryngology - Head &amp; Neck Surgery. 45 (1), 26 (2016).</li><li>Canale, 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=Interleukin-27+inhibits+pediatric+B-acute+lymphoblastic+leukemia+cell+spreading+in+a+preclinical+model.">Interleukin-27 inhibits pediatric B-acute lymphoblastic leukemia cell spreading in a preclinical model.</a> Leukemia. 25, 1815 (2011).</li><li>Loos, 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=Amino-functionalized+nanoparticles+as+inhibitors+of+mTOR+and+inducers+of+cell+cycle+arrest+in+leukemia+cells.">Amino-functionalized nanoparticles as inhibitors of mTOR and inducers of cell cycle arrest in leukemia cells.</a> Biomaterials. 35 (6), 1944-1953 (2014).</li><li>Rovithi, 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=Development+of+bioluminescent+chick+chorioallantoic+membrane+(CAM)+models+for+primary+pancreatic+cancer+cells:+a+platform+for+drug+testing.">Development of bioluminescent chick chorioallantoic membrane (CAM) models for primary pancreatic cancer cells: a platform for drug testing.</a> Scientific Reports. 7, 44686 (2017).</li><li>Majern&#237;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=Novel+Insights+into+the+Effect+of+Hyperforin+and+Photodynamic+Therapy+with+Hypericin+on+Chosen+Angiogenic+Factors+in+Colorectal+Micro-Tumors+Created+on+Chorioallantoic+Membrane.">Novel Insights into the Effect of Hyperforin and Photodynamic Therapy with Hypericin on Chosen Angiogenic Factors in Colorectal Micro-Tumors Created on Chorioallantoic Membrane.</a> International Journal of Molecular Science. 20 (12), 3004 (2019).</li><li>Swadi, 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=Optimising+the+chick+chorioallantoic+membrane+xenograft+model+of+neuroblastoma+for+drug+delivery.">Optimising the chick chorioallantoic membrane xenograft model of neuroblastoma for drug delivery.</a> BMC Cancer. 18 (1), 28 (2018).</li><li>Klingenberg, M., Becker, J., Eberth, S., Kube, D., Wilting, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chick+chorioallantoic+membrane+as+an+in+vivo+xenograft+model+for+Burkitt+lymphoma.">The chick chorioallantoic membrane as an in vivo xenograft model for Burkitt lymphoma.</a> BMC Cancer. 14 (1), 339 (2014).</li><li>Avram, 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=Standardization+of+A375+human+melanoma+models+on+chicken+embryo+chorioallantoic+membrane+and+Balb/c+nude+mice.">Standardization of A375 human melanoma models on chicken embryo chorioallantoic membrane and Balb/c nude mice.</a> Oncology Reports. 38 (1), 89-99 (2017).</li><li>Zabielska-Koczywas, K., 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=3D+chick+embryo+chorioallantoic+membrane+model+as+an+in+vivo+model+to+study+morphological+and+histopathological+features+of+feline+fibrosarcomas.">3D chick embryo chorioallantoic membrane model as an in vivo model to study morphological and histopathological features of feline fibrosarcomas.</a> BMC Veterinary Research. 13 (1), 201 (2017).</li><li>Skowron, M. 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=Applying+the+chicken+embryo+chorioallantoic+membrane+assay+to+study+treatment+approaches+in+urothelial+carcinoma.">Applying the chicken embryo chorioallantoic membrane assay to study treatment approaches in urothelial carcinoma.</a> Urologic Oncology: Seminars and Original Investigations. 35 (9), e511-e523 (2017).</li><li>Jefferies, 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=Non-invasive+imaging+of+engineered+human+tumors+in+the+living+chicken+embryo.">Non-invasive imaging of engineered human tumors in the living chicken embryo.</a> Scientific Reports. 7 (1), 4991 (2017).</li><li>Taizi, M., Deutsch, V. R., Leitner, A., Ohana, A., Goldstein, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+and+rapid+in+vivo+system+for+testing+therapeutics+on+human+leukemias.">A novel and rapid in vivo system for testing therapeutics on human leukemias.</a> Experimental Hematology. 34 (12), 1698-1708 (2006).</li><li>Strojnik, T., Kavalar, R., Barone, T. A., Plunkett, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+model+and+immunohistochemical+comparison+of+U87+human+glioblastoma+cell+xenografts+on+the+chicken+chorioallantoic+membrane+and+in+rat+brains.">Experimental model and immunohistochemical comparison of U87 human glioblastoma cell xenografts on the chicken chorioallantoic membrane and in rat brains.</a> Anticancer Research. 30 (12), 4851-4860 (2010).</li><li>Ribatti, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chick+embryo+chorioallantoic+membrane+as+a+model+for+tumor+biology.">The chick embryo chorioallantoic membrane as a model for tumor biology.</a> Experimental Cell Research. 328 (2), 314-324 (2014).</li><li>Hu, 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=A+Non-integrating+Lentiviral+Approach+Overcomes+Cas9-Induced+Immune+Rejection+to+Establish+an+Immunocompetent+Metastatic+Renal+Cancer+Model.">A Non-integrating Lentiviral Approach Overcomes Cas9-Induced Immune Rejection to Establish an Immunocompetent Metastatic Renal Cancer Model.</a> Molecular Therapy - Methods &amp; Clinical Development. 9, 203-210 (2018).</li></ol>

The authors have nothing to disclose.

Tumor expansion and engraftment using the CAM model permits more rapid and directly observable tumor growth than existing in vivo animal models. In addition, costs are significantly lower once the initial purchase of equipment is complete, especially when compared to the cost of immunocompromised mice. The initial, immunocompromised state of chicken embryos readily permits engraftment of human and murine tissue. Even with these strengths, the CAM model does have limitations. The short time that can be a benefit could also be a detriment if long-term treatment studies are warranted. The immunocompromised/immune tolerant status of the CAM model could complicate studies of tumor-immune interactions. For these studies, coimplantation of immune cells of interest may be necessary, possibly with replenishment of the immune compartment. Furthermore, although all the tumor types we presented engraft into the CAM model, they do so with varying degrees of growth. For example, renal cell carcinoma rapidly forms large tumors, but ovarian cancer tumors are difficult to visualize without the assistance of bioluminescence imaging. Tumor growth and speed would need to be assessed for a particular tumor type to determine if the CAM would be a suitable experimental model.
Successful tumor engraftment requires the careful completion of specific steps of the protocol. First, eggs need to be incubated under ideal conditions to have optimal embryo survival and CAM formation prior to engraftment. Due to the natural variability in batches, we suggest obtaining excess eggs from the specific egg supplier. We have also found that cooler, rainier weather can lead to fungal growth in the eggs. During wetter weather, more eggs may need to be engrafted to obtain adequate yields at the endpoint. This seasonal variation is likely to be region-specific. Adequate CAM formation is essential for successful tumor engraftment. Any indications of the CAM remaining attached to the shell when opening should not be ignored. If several eggs fail to have intact CAM when opening the first batch, then we recommend delaying the opening of the remaining eggs for at least 1 additional day.
If poor viability or engraftment are obtained, several steps could be at fault. First, the embryo viability from the supplier may be poor. Absence of an air cell and visible vasculature indicates a nonviable egg. Sometimes, embryo movement can be visualized to confirm viability. First, though, ensure that fresh batteries are in the egg candler, because a strong light is needed for visualization. The float test may also be done to assess viability (a variety of instructions and videos are available online). Another possible explanation for poor viability is the incubator. Using an independent hygrometer and thermometer, ensure that the settings are accurate and stable. Manufacturer&#39;s instructions for the incubator should contain detailed troubleshooting instructions to assess proper settings. Improper incubator settings could also compromise CAM development. Using tape and/or a marker, determine if the egg rotator is actually spinning the eggs. If nonstick rings sink into the albumin in a high proportion of the engrafted eggs, then the CAM did not adequately develop. Finally, we have found that frequent checking of the engrafted egg, leading to temperature and humidity fluctuations, may decrease postimplant viability. If implanted eggs are initially viable, but the viability decreases throughout the engraftment period, the eggs should be checked less frequently. This decrease in viability could also be due to inaccurate or inappropriate incubator settings after implantation.
When optimizing this method for a new cell type, several factors can be controlled. The first is cell number. We typically implant 5 x 105-2 x 106 cells from cell lines. Implanted tumor pieces are typically 2-5 mm on each side. These amounts may be adjusted to improve engraftment or size. However, we have found that tumor growth lessens above a certain threshold, which is cell type dependent. Additional engraftment parameters include the presence or absence of a nonstick ring. This choice is typically made based on whether the ring will hinder the endpoint analysis, although it may also influence successful engraftment. The presence of the nonstick ring may also permit covering the nascent graft with medium at desired intervals to improve survival prior to vascular recruitment, if so desired. The choice of extracellular matrix type, concentration, and medium in which the matrix is diluted may also impact engraftment. The addition of growth factors or hormones may further improve tumor take rate or size. The selection of additives and concentrations would need to be done based on what would be appropriate for the specific cell type and not interfere with the experiment. These would also have the potential to be replenished at intervals if a nonstick ring is used.
Future applications of this model system depend on the hypothesis to be tested. For example, these tumor grafts could be used to test novel therapeutic approaches to reduce tumor size or deplete a subpopulation of the tumor. Co-implantation with cells from the host tumor microenvironment could permit studies of the influence of these cells on a variety of parameters, including tumor growth and treatment resistance. This model could also serve as an opportunity to incrementally expand primary human tumors prior to establishing xenografts in immunocompromised animal models. The initial adaptation to CAM engraftment could perhaps facilitate tumor take rate in murine models. These applications have yet to be tested, but warrant further exploration.

Mice have served as the classic model organism for the study of human diseases, including malignancy. As mammals, they share many similarities with humans. Their high degree of genetic similarity has permitted transgenic manipulation of the mouse genome to provide enormous insight into the genetic control of human diseases1. Extensive experience in the handling of and experimentation with mice has resulted in their being the model of choice for biomedical research. However, in addition to the ethical and scientific concerns regarding murine models, they can also be quite costly and time consuming2,3. The development of tumors can take weeks or even months. The housing at a typical institution alone can run in the hundreds to thousands of dollars while tumors are developing. Ovarian cancer is an example of this drawback because its growth in murine models can easily take months. Delays in research progress potentially impact ovarian cancer patients&#39; persistently low 5-year survival rate of only 47% (i.e., an increase in survival of only 10% over 30 years)4. Similarly, urological cancers (kidney, prostate, and bladder cancers) constitute 19% of all cancer cases in the United States and 11% of cancer-related deaths4. Thus, a novel in vivo approach to study gynecological and urological cancers could save a laboratory considerable time, labor, and money, even if this model is only applied to initial screening experiments. Additionally, the resulting acceleration of research findings could significantly impact the 177,000 individuals diagnosed with these cancers annually.
The chicken CAM model offers many advantages that address the aforementioned issues. A popular model to study angiogenesis5,6, tumor cell invasion7,8, and metastasis7,9, the chick embryo CAM model has already been used to study many forms of cancers, including glioma10,11,12, head and neck squamous cell carcinoma13,14, leukemia15,16, pancreatic cancer17, and colorectal cancer18. Additionally, CAM models have been generated for neuroblastoma19, Burkitt lymphoma20, melanoma21, and feline fibrosarcoma22. Prior studies have also presented engraftment of bladder cancer23 and prostate cancer cell lines24, but with limited protocol details. Not only are eggs much cheaper than mice, but they also produce highly reproducible results25,26. They show fast vasculature development, and tumor engraftment can occur in as quickly as a few days and be visualized longitudinally through the open window. With the 21 day time frame between egg fertilization and hatching, experiments can be completed within a few weeks. Furthermore, the low cost, limited housing needs, and small size readily permit large-scale experiments that would be prohibitive for mouse studies.
Therefore, we sought to optimize the CAM model for the engraftment of gynecological and urological cancers. Due to the immunocompromised status of the early chicken embryo27, both mouse and human cells can be readily implanted. As such, we have successfully engrafted ovarian, kidney, prostate, and bladder cancers. For each of these tumor types, the CAM readily accepts established murine and/or human tumor cell lines. Importantly, freshly harvested primary human tumor tissues can also engraft from either digested cells or pieces of solid tissue with high rates of success. Each of these cancer types and cell sources requires optimization, which we share here.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>-010 Teflon (PTFE) White 55 Duro Shore D O-Rings</td>
			<td>The O-Ring Store</td>
			<td>TEF010</td>
			<td>Nonstick ring for cell seeding. 1/4&#34;ID X 3/8&#34;OD X 1/16&#34;CS Polytetrafluoroethylene (PTFE).</td>
		</tr>
		<tr>
			<td>C4-2</td>
			<td>ATCC</td>
			<td>CRL-3314</td>
			<td>Human prostate cancer cell line.</td>
		</tr>
		<tr>
			<td>CWR22Rv1</td>
			<td></td>
			<td></td>
			<td>CWR cells were the kind gift of Dr. David Agus (Keck Medicine of University of Southern California)</td>
		</tr>
		<tr>
			<td>Cytokeratin 8/18 Antibody (C-51)</td>
			<td>Novus Biologicals</td>
			<td>NBP2-44929-0.02mg</td>
			<td>Used at a dilution of 1:100 for immunohistochemical analysis of human ovarian CAM tumors.</td>
		</tr>
		<tr>
			<td>D-Luciferin Firefly, potassium salt</td>
			<td>Goldbio</td>
			<td>LUCK-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Delicate Operating Scissors; Curved; Sharp-Sharp; 30mm Blade Length; 4-3/4 in. Overall Length</td>
			<td>Roboz Surgical</td>
			<td>RS6703</td>
			<td>This is provided as an example. Any similar curved scissors would work as well.</td>
		</tr>
		<tr>
			<td>Dremel 8050-N/18 Micro 8V Max Tool Kit</td>
			<td>Dremel</td>
			<td>8050-N/18</td>
			<td>This kit contains all necessary tools.</td>
		</tr>
		<tr>
			<td>Fertilized chicken eggs (Rhode Island Red - Brown, Lab Grade)</td>
			<td>AA Lab Eggs Inc.</td>
			<td>N/A</td>
			<td>A local egg supplier would need to be identified, as this supplier only delivers regionally.</td>
		</tr>
		<tr>
			<td>HT-1376</td>
			<td>ATCC</td>
			<td>CRL-1472</td>
			<td>Human bladder cancer cell line.</td>
		</tr>
		<tr>
			<td>Hovabator Genesis 1588 Deluxe Egg Incubator Combo Kit</td>
			<td>Incubator Warehouse</td>
			<td>HB1588D-NONE-1102-1588-1357</td>
			<td>Other egg incubators may be used, but their reliability would need to be verified. After implantation, a cell incubator with the CO2 disabled may also be used.</td>
		</tr>
		<tr>
			<td>ID8</td>
			<td></td>
			<td></td>
			<td>Not commercially available, please see PMID: 10753190.</td>
		</tr>
		<tr>
			<td>Incu-Bright Cool Light Egg Candler</td>
			<td>Incubator Warehouse</td>
			<td>1102</td>
			<td>Other candlers may be used; however, this is preferred among those that we have tested. This candler is included in the aforementioned incubator kit.</td>
		</tr>
		<tr>
			<td>Iris Forceps, 10cm, Curved, Serrated, 0.8mm tips</td>
			<td>World Precision Instrument</td>
			<td>15915</td>
			<td>This is provided as an example. Any similar curved forceps would work as well. Multiple brands have been used for this method.</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Clipper Distributing</td>
			<td>0010250</td>
			<td></td>
		</tr>
		<tr>
			<td>IVIS Lumina II In Vivo Imaging System</td>
			<td>Perkin Elmer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel Membrane Matrix HC; LDEV-Free</td>
			<td>Corning</td>
			<td>354248</td>
			<td>Extracellular matrix solution</td>
		</tr>
		<tr>
			<td>MyC-CaP</td>
			<td>ATCC</td>
			<td>CRL-3255</td>
			<td>Murine prostate cancer cell line.</td>
		</tr>
		<tr>
			<td>Portable Pipet-Aid XP Pipette Controller</td>
			<td>Drummond Scientific</td>
			<td>4-000-101</td>
			<td>Any similar pipet controller would be appropriate.</td>
		</tr>
		<tr>
			<td>PrecisionGlide Hypodermic Needles</td>
			<td>BD</td>
			<td>305196</td>
			<td>This is provided as an example. Any 18G needle would work similarly.</td>
		</tr>
		<tr>
			<td>RENCA</td>
			<td>ATCC</td>
			<td>CRL-2947</td>
			<td></td>
		</tr>
		<tr>
			<td>Semken Forceps</td>
			<td>Fine Science Tools</td>
			<td>11008-13</td>
			<td>This is provided as an example. Any similar forceps or another style that suits researcher preference would be appropriate.</td>
		</tr>
		<tr>
			<td>SKOV3</td>
			<td>ATCC</td>
			<td>HTB-77</td>
			<td>Human ovarian cancer cell line.</td>
		</tr>
		<tr>
			<td>Specimen forceps</td>
			<td>Electron Microscopy Sciences</td>
			<td>72914</td>
			<td>This is provided as an example. The forceps used for pulling away the shell for bioluminescence imaging are approximately 12.8 cm long with 3 mm-wide tips.</td>
		</tr>
		<tr>
			<td>Sterile Cotton Balls</td>
			<td>Fisherbrand</td>
			<td>22-456-885</td>
			<td>This is provided as an example. Any sterile cotton balls would suffice.</td>
		</tr>
		<tr>
			<td>Stirring Rods with Rubber Policeman; 5mm diameter, 6 in. length</td>
			<td>United Scientific Supplies</td>
			<td>GRPL06</td>
			<td>This is provided as an example. Any similar glass stir rods would work as well.</td>
		</tr>
		<tr>
			<td>T24</td>
			<td>ATCC</td>
			<td>HTB-4</td>
			<td>Human bladder cancer cell line.</td>
		</tr>
		<tr>
			<td>Tegaderm Transparent Dressing Original Frame Style 2 3/8&#34; x 2 3/4&#34;</td>
			<td>Moore Medical</td>
			<td>21272</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Culture Dishes, 10 cm diameter</td>
			<td>Corning</td>
			<td>353803</td>
			<td>This is provided as an example. Any similar, sterile 10-cm dish may be used. Tissue culture treatment is not necessary.</td>
		</tr>
		<tr>
			<td>Tygon Clear Laboratory Tubing - 1/4 x 3/8 x 1/16 wall (50 feet)</td>
			<td>Tygon</td>
			<td>AACUN017</td>
			<td>This is provided as an example. Any similarly sized tubing would work as well.</td>
		</tr>
	</tbody>
</table>

using the chicken chorioallantoic membrane in vivo model to study gynecological and urological cancers

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo cancer models. The chicken chorioallantoic membrane (CAM) model provides an inexpensive, rapid alternative that permits direct visualization of tumor development and is suitable for in vivo imaging. As such, we sought to develop an optimized protocol for engrafting gynecological and urological tumors into this model, which we present here. Approximately 7 days postfertilization, the air cell is moved to the vascularized side of the egg, where an opening is created in the shell. Tumors from murine and human cell lines and primary tissues can then be engrafted. These are typically seeded in a mixture of extracellular matrix and medium to avoid cellular dispersal and provide nutrient support until the cells recruit a vascular supply. Tumors may then grow for up to an additional 14 days prior to the eggs hatching. By implanting cells stably transduced with firefly luciferase, bioluminescence imaging can be used for the sensitive detection of tumor growth on the membrane and cancer cell spread throughout the embryo. This model can potentially be used to study tumorigenicity, invasion, metastasis, and therapeutic effectiveness. The chicken CAM model requires significantly less time and financial resources compared to traditional murine models. Because the eggs are immunocompromised and immune tolerant, tissues from any organism can potentially be implanted without costly transgenic animals (e.g., mice) required for implantation of human tissues. However, many of the advantages of this model could potentially also be limitations, including the short tumor generation time and immunocompromised/immune tolerant status. Additionally, although all tumor types presented here engraft in the chicken chorioallantoic membrane model, they do so with varying degrees of tumor growth.

Thus far, we have found this method of implantation to be successful for ovarian, kidney, prostate, and bladder cancers. Each was optimized to identify specific conditions for implantation, although there may be flexibility. Of the tested tumor types, ovarian cancer growth was much less pronounced and typically not visible without the assistance of bioluminescence imaging (Figure 1). However, a stiffening of the CAM could be felt with forceps in the area of implantation. This may help identify possible tumor growth in the absence of bioluminescence imaging, though further validation would be required via histology or another suitable method. We achieved successful engraftment of both human and murine cell lines that show morphologies consistent with those seen in other in vivo models (Figure 1A and 1B). In addition, the implantation of tumor pieces was possible (Figure 1C, blue arrow indicates tumor). The implanted tumor in this case came from a patient with high-grade, metastatic, ovarian serous carcinoma. The resulting tumors morphologically resembled their tumors of origin and expressed human-specific proteins, such as cytokeratin 8/18, that readily permit their differentiation from CAM and chicken embryonic tissues.
When optimizing tumor engraftment and growth, appropriate growth factors or hormones may be added at the time of implantation. For example, a subtle, nonsignificant increase in tumor size (as measured by total radiance flux) was observed in ID8 cells when supplemented with three units (U) of human follicle stimulating hormone (FSH) at the time of implantation (Figure 1D). The selection of FSH for ovarian cancer growth stemmed from the expression of the FSH receptor in ID8 cells and the high levels of FSH typically found in postmenopausal women, who constitute the majority of ovarian cancer cases. Similar approaches may be adopted for other difficult-to-grow cancer types to enhance the utility of the CAM model. Furthermore, FSH was only added at the time of cell implantation. Replenishing the growth factor or hormone could be accomplished by pipetting an appropriate amount of the additive in the medium into the nonstick ring at appropriate intervals, which could enhance the effect.
For kidney cancer, implantation of 2 x 106 clear cell renal cell carcinoma cells from established cell lines, such as RENCA, produced rapid, robust tumor formation, though lower cell doses may also be used (Figure 2A, 10 days postimplantation). Resulting tumors morphologically resembled those obtained through standard mouse in vivo models28. Implantation of RENCA cells marked with firefly luciferase permitted bioluminescence imaging. Primary human tumors may also be implanted. The pieces of tumor persisted and recruited vasculature without showing significant growth. Implantation of digested cells originating from a primary, clear cell renal cell carcinoma that were expanded in vitro, however, grew similarly to the established cell lines (Figure 2B). Renal cell carcinoma cells may be seeded using either the nonstick ring method or the method without the nonstick ring.
Multiple human and murine prostate cancer cell lines were tested for CAM engraftment (Figure 3). Each grew well when 2 x 106 cells were implanted using the nonstick ring. Histological evaluation of the resulting tumors was consistent with expectations for each cell line. Additionally, implantation of cells stably marked with firefly luciferase permitted tumor identification with bioluminescence imaging (Figure 3A).
Bladder cancer was established in the CAM model from established cell lines and pieces of primary human tissue (Figure 4). Cell lines grew well when implanted with 2 x 106 cells without the nonstick ring (Figure 4A and 4B), although implantation with the ring was successful. Primary human tumor may be implanted from pieces of tissue (Figure 4C). The presented case originated from a patient with high grade, non-muscle-invasive, urothelial carcinoma. Implantation of digested cells has not yet been attempted due to ongoing tumor digestion optimization. Cancer cells of the resulting CAM tumors retained the morphology of the original tumor, but with an altered stromal component. Tumor growth was less than for renal cell carcinoma and prostate cancer, though still readily visible.
To ensure a high number of viable, assayable eggs at the endpoint, care must be taken when incubating and opening the eggs. If the incubator conditions are suboptimal either before or after implantation, then embryo viability may be compromised. If significant embryonic death occurs, troubleshoot the incubator conditions according to the manufacturer&#39;s instructions. In our experience, temperature and humidity stability appear to be more crucial than their exact values. Therefore, we found that incubating the inoculated eggs in a modified, cell-culture, CO2 incubator achieved superior viability over retaining the eggs in small, dedicated egg incubators that require more frequent opening to replenish the water that controls the humidity. Minimizing the frequency with which the inoculated eggs are removed for tumor examination may also enhance embryo viability.
An additional concern of CAM implantation is the integrity of the CAM at inoculation. If the CAM is not intact after opening the shell, then the nonstick ring and implanted cells will sink into the albumin of the embryo (see the note after step 2.12). This causes cancer cell dispersal. Some tumors may still form, but cancers that receive significant growth and survival signaling from neighboring cancer cells, such as ovarian cancer, will not reliably form tumors under such conditions. If nonstick rings are used for implantation, the failure of the CAM can be identified by the sinking of the ring into the albumin. This must be distinguished from cases in which the ring and implanted cells were moved to the bottom of the egg by embryonic movement. In those cases, the ring will be found between the CAM and the underside of the shell. Embryonic movement cannot be controlled. However, ring placement can make it more difficult for the embryo to disrupt the implanted cells. Rings placed at the edges of the air pocket generated in step 2.7 are more likely to be moved by the embryo than those placed at the center of the field.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60651/60651fig1a.jpg" /> 
Figure 1: Representative tumor development from ovarian cancer. Ovarian cancer cells successfully implanted include: (A) the human SKOV3 cell line, (B) the murine ID8 cell line, and (C) primary tumors. Representative hematoxylin and eosin staining is presented along with bioluminescence imaging, as appropriate. For the CAM tumor resulting from the implantation of a primary tumor piece (C) hematoxylin and eosin staining of both the CAM tumor and primary tumor are included, along with cytokeratin 8/18 (CK 8/18) staining of the resulting CAM tumor. The blue arrow in the first panel indicates the tumor. (D) Tumor size of ID8 implants with and without 3U FSH, calculated as the total flux resulting from bioluminescence imaging (n = 3 for untreated and n = 4 for FSH-supplemented). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60651/60651fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/60651/60651fig2.jpg" /> 
Figure 2: Representative tumor development from clear cell renal cell carcinoma. Tumors resulting from implantation of (A) the murine renal cell carcinoma cell line, RENCA, or (B) cultured cells derived from a digested human primary tumor. The measurement scale adjacent to the excised tumor in (B) shows 1 mm markings. Corresponding histology in (A) and (B) shows hematoxylin and eosin staining. In (A), the representative bioluminescence imaging of firefly-luciferase-marked RENCA cells is also shown. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60651/60651fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/60651/60651fig3.jpg" /> 
Figure 3: Representative tumor development from prostate cancer cell lines. Representative tumors and hematoxylin and eosin staining resulting from the implantation of the human prostate cancer cell lines (A) CWR and (B) C4-2 along with the murine cell line (C) MyC-CaP. Bioluminescence imaging of the resulting tumors from firefly luciferase marked CWR cells is shown in (A). The measurement scale adjacent to the excised tumors shows 1 mm markings. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60651/60651fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/60651/60651fig4a.jpg" /> 
Figure 4: Representative tumor development from bladder cancer. Representative tumors resulting from the implantation of the established human bladder cancer cell lines (A) HT-1376, (B) T24, and (C) primary human bladder tumor. In (C), hematoxylin and eosin staining of the resulting CAM tumor and the primary tumor are shown. The measurement scale adjacent to the excised tumors shows 1 mm markings. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/60651/60651fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers at JoVE.com

Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers

We present the chicken chorioallantoic membrane model as an alternative, transplantable, in vivo model for the engraftment of gynecological and urological cancer cell lines and patient-derived tumors.

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo ...

using-chicken-chorioallantoic-membrane-vivo-model-to-study

Nanyang Technological University

Research

JoVE Journal

Cancer Research

10.1K Views.  University of California Los Angeles. We present the chicken chorioallantoic membrane model as an alternative, transplantable, in vivo model for the engraftment of gynecological and urological cancer cell lines and patient-derived tumors.

Video: Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers

Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased understanding of the molecular events that give rise to glioblastomas, this cancer still remains highly refractory to conventional treatment. Surgical resection of high grade brain tumors is rarely complete due to the highly infiltrative nature of glioblastoma cells. Therapeutic approaches which attenuate glioblastoma cell invasion therefore is an attractive option. Our laboratory and others have shown that tumor associated macrophages and microglia (resident brain macrophages) strongly stimulate glioblastoma invasion. The protocol described in this paper is used to model glioblastoma-macrophage/microglia interaction using in vitro culture assays. This approach can greatly facilitate the development and/or discovery of drugs that disrupt the communication with the macrophages that enables this malignant behavior. We have established two robust coculture invasion assays where microglia/macrophages stimulate glioma cell invasion by 5 - 10 fold. Glioblastoma cells labelled with a fluorescent marker or constitutively expressing a fluorescent protein are plated without and with macrophages/microglia on matrix-coated polycarbonate chamber inserts or embedded in a three dimensional matrix. Cell invasion is assessed by using fluorescent microscopy to image and count only invasive cells on the underside of the filter. Using these assays, several pharmacological inhibitors (JNJ-28312141, PLX3397, Gefitinib, and Semapimod), have been identified which block macrophage/microglia stimulated glioblastoma invasion.

Understanding the malignant behavior of cancer requires creating accurate models of how tumor cells interact with components of the tumor microenvironment, such as macrophages. Here we describe two methods to study glioblastoma cell interaction with tumor associated macrophages and microglia where the effect on glioblastoma invasion is assessed.

Glioblastoma multiforme (grade IV glioma) is a very aggressive human cancer with a median survival of 1 year post diagnosis. Despite the increased ...

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the context of a whole organism. Sophisticated techniques to generate genetic mosaics facilitate induction of visually marked, genetically defined clones surrounded by normal tissue. The clones can be analyzed through diverse molecular, cellular and omics approaches. This study describes how to generate fluorescently labeled clonal tumors of varying malignancy in the eye/antennal imaginal discs (EAD) of Drosophila larvae using the Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. It describes procedures how to recover the mosaic EAD and brain from the larvae and how to process them for simultaneous imaging of fluorescent transgenic reporters and antibody staining. To facilitate molecular characterization of the mosaic tissue, we describe a protocol for isolation of total RNA from the EAD. The dissection procedure is suitable to recover EAD and brains from any larval stage. The fixation and staining protocol for imaginal discs works with a number of transgenic reporters and antibodies that recognize Drosophila proteins. The protocol for RNA isolation can be applied to various larval organs, whole larvae, and adult flies. Total RNA can be used for profiling of gene expression changes using candidate or genome-wide approaches. Finally, we detail a method for quantifying invasiveness of the clonal tumors. Although this method has limited use, its underlying concept is broadly applicable to other quantitative studies where cognitive bias must be avoided.

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

This protocol demonstrates how to generate fluorescently marked, genetically defined clonal tumors in the Drosophila eye/antennal imaginal discs (EAD). It describes how to dissect the EAD and brain from the third instar larvae and how to process them to visualize and quantify gene expression changes and tumor invasiveness.

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the ...

Live Imaging to Study Microtubule Dynamic Instability in Taxane-resistant Breast Cancers

Taxanes such as docetaxel belong to a group of microtubule-targeting agents (MTAs) that are commonly relied upon to treat cancer. However, taxane resistance in cancerous cells drastically reduces the effectiveness of the drugs' long-term usage. Accumulated evidence suggests that the mechanisms underlying taxane resistance include both general mechanisms, such as the development of multidrug resistance due to the overexpression of drug-efflux proteins, and taxane-specific mechanisms, such as those that involve microtubule dynamics. 
Because taxanes target cell microtubules, measuring microtubule dynamic instability is an important step in determining the mechanisms of taxane resistance and provides insight into how to overcome this resistance. In the experiment, an in vivo method was used to measure microtubule dynamic instability. GFP-tagged &#945;-tubulin was expressed and incorporated into microtubules in MCF-7 cells, allowing for the recording of the microtubule dynamics by time lapse using a sensitive camera. The results showed that, as opposed to the non-resistant parental MCF-7CC cells, the microtubule dynamics of docetaxel-resistant MCF-7TXT cells are insensitive to docetaxel treatment, which causes the resistance to docetaxel-induced mitotic arrest and apoptosis. This paper will outline this in vivo method of measuring microtubule dynamic instability.

In this paper, we report a protocol describing an in vivo method to measure microtubule dynamic instability in docetaxel-resistant breast cancer cells (MCF-7TXT). In this method, a deconvolution microscopy imaging system is used to detect the expression of GFP-tubulin in target cells.

Taxanes such as docetaxel belong to a group of microtubule-targeting agents (MTAs) that are commonly relied upon to treat cancer. However, taxane ...

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro

Depletion of the mitochondrial membrane potential (MMP, &#916;&#936;m) is considered the earliest event in the apoptotic cascade. It even occurs ahead of nuclear apoptotic characteristics, including chromatin condensation and DNA breakage. Once the MMP collapses, cell apoptosis will initiate irreversibly. A series of lipophilic cationic dyes can pass through the cell membrane and aggregate inside the matrix of mitochondrion, and serve as fluorescence marker to evaluate MMP change. As one of the six members of the Cl- intracellular channel (CLIC) family, CLIC4 participates in the cell apoptotic process mainly through the mitochondrial pathway. Here we describe a detailed protocol to measure MMP via monitoring the fluorescence fluctuation of Rhodamine 123 (Rh123), through which we study apoptosis induced by CLIC4 knockdown. We discuss the advantages and limitations of the application of confocal laser scanning and normal fluorescence microscope in detail, and also compare it with other methods.

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro

Here we present a detailed protocol for the application of rhodamine 123 to identify the mitochondrial membrane potential (MMP) and study CLIC4 knockdown-induced HN4 cell apoptosis in vitro. Under common fluorescence microscope and confocal laser scanning fluorescence microscope, the real-time change of the MMP was recorded.

Depletion of the mitochondrial membrane potential (MMP, &#916;&#936;m) is considered the earliest event in the apoptotic cascade. It even occurs ahead of ...

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

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

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

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

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

Acellular and Cellular Lung Model to Study Tumor Metastasis

It is difficult to isolate tumor cells at different points of tumor progression. We created an ex vivo lung model that can show the interaction of tumor cells with a natural matrix and continual flow of nutrients, as well as a model that shows the interaction of tumor cells with normal cellular components and a natural matrix. The acellular ex vivo lung model is created by isolating a rat heart-lung block and removing all the cells using the decellularization process. The right main bronchus is tied off and tumor cells are placed in the trachea by a syringe. The cells move and populate the left lung. The lung is then placed in a bioreactor where the pulmonary artery receives a continual flow of media in a closed circuit. The tumor grown on the left lung is the primary tumor. The tumor cells that are isolated in the circulating media are circulating tumor cells and the tumor cells in the right lung are metastatic lesions. The cellular ex vivo lung model is created by skipping the decellularization process. Each model can be used to answer different research questions.

Here, we present a protocol for an ex vivo lung cancer model that mimics the steps of tumor progression and helps to isolate a primary tumor, circulating tumor cells, and metastatic lesions.

It is difficult to isolate tumor cells at different points of tumor progression. We created an ex vivo lung model that can show the interaction of tumor ...

Obtaining Cancer Stem Cell Spheres from Gynecological and Breast Cancer Tumors

Cancer stem cells (CSC) are a small population with self-renewal and plasticity which are responsible for tumorigenesis, resistance to treatment and recurrent disease. This population can be identified by surface markers, enzymatic activity and a functional profile. These approaches per se are limited, due to phenotypic heterogeneity and CSC plasticity. Here, we update the sphere-forming protocol to obtain CSC spheres from breast and gynecological cancers, assessing functional properties, CSC markers and protein expression. The spheres are obtained with single-cell seeding at low density in suspension culture, using a semi-solid methylcellulose medium to avoid migration and aggregates. This profitable protocol can be used in cancer cell lines but also in primary tumors. The tridimensional non-adherent suspension culture thought to mimic the tumor microenvironment, particularly the CSC-niche, is supplemented with epidermal growth factor and basic fibroblast growth factor to ensure CSC signaling. Aiming for robust identification of CSC, we propose a complementary approach, combining functional and phenotypic evaluation. Sphere-forming capacity, self-renewal and sphere projection area establish CSC functional properties. Additionally, characterization comprises flow cytometry evaluation of the markers, represented by CD44+/CD24- and CD133, and Western blot, considering ALDH. The presented protocol was also optimized for primary tumor samples, following a sample digestion procedure, useful for translational research.

The aim of this methodology is to identify cancer stem cells (CSC) in cancer cell lines and primary human tumor samples with the sphere-forming protocol, in a robust manner, using functional assays and phenotypic characterization with flow cytometry and Western blot.

Cancer stem cells (CSC) are a small population with self-renewal and plasticity which are responsible for tumorigenesis, resistance to treatment and ...

Comparing Metastatic Clear Cell Renal Cell Carcinoma Model Established in Mouse Kidney and on Chicken Chorioallantoic Membrane

Metastatic clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer. Localized ccRCC has a favorable surgical outcome. However, one third of ccRCC patients will develop metastases to the lung, which is related to a very poor outcome for patients. Unfortunately, no therapy is available for this deadly stage, because the molecular mechanism of metastasis remains unknown. It has been known for 25 years that the loss of function of the von Hippel-Lindau (VHL) tumor suppressor gene is pathognomonic of ccRCC. However, no clinically relevant transgenic mouse model of ccRCC has been generated. The purpose of this protocol is to introduce and compare two newly established animal models for metastatic ccRCC. The first is renal implantation in the mouse model. In our laboratory, the CRISPR gene editing system was utilized to knock out the VHL gene in several RCC cell lines. Orthotopic implantation of heterogeneous ccRCC populations to the renal capsule created novel ccRCC models that develop robust lung metastases in immunocompetent mice. The second model is the chicken chorioallantoic membrane (CAM) system. In comparison to the mouse model, this model is more time, labor, and cost-efficient. This model also supported robust tumor formation and intravasation. Due to the short 10 day period of tumor growth in CAM, no overt metastasis was observed by immunohistochemistry (IHC) in the collected embryo tissues. However, when tumor growth was extended by two weeks in the hatched chicken, micrometastatic ccRCC lesions were observed by IHC in the lungs. These two novel preclinical models will be useful to further study the molecular mechanism behind metastasis, as well as to establish new, patient-derived xenografts (PDXs) toward the development of novel treatments for metastatic ccRCC.

Metastatic clear cell renal cell carcinoma is a disease without a comprehensive animal model for thorough preclinical investigation. This protocol illustrates two novel animal models for the disease: the orthotopically implanted mouse model and the chicken chorioallantoic membrane model, both of which demonstrate lung metastasis resembling clinical cases.

Metastatic clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer. Localized ccRCC has a favorable surgical outcome. However, ...

Using Computer-based Image Analysis to Improve Quantification of Lung Metastasis in the 4T1 Breast Cancer Model

Breast cancer is a devastating malignancy, accounting for 40,000 female deaths and 30% of new female cancer diagnoses in the United States in 2019 alone. The leading cause of breast cancer related deaths is the metastatic burden. Therefore, preclinical models for breast cancer need to analyze metastatic burden to be clinically relevant. The 4T1 breast cancer model provides a spontaneously-metastasizing, quantifiable mouse model for stage IV human breast cancer. However, most 4T1 protocols quantify the metastatic burden by manually counting stained colonies on tissue culture plates. While this is sufficient for tissues with lower metastatic burden, human error in manual counting causes inconsistent and variable results when plates are confluent and difficult to count. This method offers a computer-based solution to human counting error. Here, we evaluate the protocol using the lung, a highly metastatic tissue in the 4T1 model. Images of methylene blue-stained plates are acquired and uploaded for analysis in Fiji-ImageJ. Fiji-ImageJ then determines the percentage of the selected area of the image that is blue, representing the percentage of the plate with metastatic burden. This computer-based approach offers more consistent and expeditious results than manual counting or histopathological evaluation for highly metastatic tissues. The consistency of Fiji-ImageJ results depends on the quality of the image. Slight variations in results between images can occur, thus it is recommended that multiple images are taken and results averaged. Despite its minimal limitations, this method is an improvement to quantifying metastatic burden in the lung by offering consistent and rapid results.

We describe a more consistent and expeditious method to quantify lung metastasis in the 4T1 breast cancer model by using Fiji-ImageJ.

Breast cancer is a devastating malignancy, accounting for 40,000 female deaths and 30% of new female cancer diagnoses in the United States in 2019 alone. ...

Discovery of Metastatic Regulators using a Rapid and Quantitative Intravital Chick Chorioallantoic Membrane Model

Recent advances in cancer research has illustrated the highly complex nature of cancer metastasis. Multiple genes or genes networks have been found to be involved in differentially regulating cancer metastatic cascade genes and gene products dependent on the cancer type, tissue, and individual patient characteristics. These represent potentially important targets for genetic therapeutics and personalized medicine approaches. The development of rapid screening platforms is essential for the identification of these genetic targets.
The chick chorioallantoic membrane (CAM) is a highly vascularized, collagen rich membrane located under the eggshell that allows for gas exchange in the developing embryo. Due to the location and vascularization of the CAM, we developed it as an intravital human cancer metastasis model that allows for robust human cancer cell xenografting and real-time imaging of cancer cell interactions with the collagen rich matrix and vasculature. 
Using this model, a quantitative screening platform was designed for the identification of novel drivers or suppressors of cancer metastasis. We transduced a pool of head and neck HEp3 cancer cells with a complete human genome shRNA gene library, then injected the cells, at low density, into the CAM vasculature. The cells proliferated and formed single-tumor cell colonies. Individual colonies that were unable to invade into the CAM tissue were visible as a compact colony phenotype and excised for identification of the transduced shRNA present in the cells. Images of individual colonies were evaluated for their invasiveness. Multiple rounds of selections were performed to decreases the rate of false positives. Individual, isolated cancer cell clones or newly engineered clones that express genes of interest were subjected to primary tumor formation assay or cancer cell vasculature co-option analysis. In summary we present a rapid screening platform that allows for anti-metastatic target identification and intravital analysis of a dynamic and complex cascade of events.

This is an effective method to screen for suppressors or drivers of cancer metastasis. Cells, transduced with an expression library, are injected into the chicken chorioallantoic membrane vasculature to form metastatic colonies. Colonies having decreased or increased invasiveness are excised, expanded, reinjected to confirm their phenotype, and finally, analyzed using high throughput sequencing.

Recent advances in cancer research has illustrated the highly complex nature of cancer metastasis. Multiple genes or genes networks have been found to be ...

Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers

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Coculture Assays to Study Macrophage and Microglia Stimulation of Glioblastoma Invasion

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Live Imaging to Study Microtubule Dynamic Instability in Taxane-resistant Breast Cancers

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro

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

Acellular and Cellular Lung Model to Study Tumor Metastasis

Obtaining Cancer Stem Cell Spheres from Gynecological and Breast Cancer Tumors

Comparing Metastatic Clear Cell Renal Cell Carcinoma Model Established in Mouse Kidney and on Chicken Chorioallantoic Membrane

Using Computer-based Image Analysis to Improve Quantification of Lung Metastasis in the 4T1 Breast Cancer Model

Discovery of Metastatic Regulators using a Rapid and Quantitative Intravital Chick Chorioallantoic Membrane Model