The authors thank Ms. Kaylee Smith, Ms. Lauren Kwok, and Mr. Alexander Floru for proofreading the manuscript. H.F. acknowledges grant support from the NIH (CA134743 and CA215059), the American Cancer Society (RSG-17-204 01-TBG), and the St. Baldrick&#39;s Foundation. F.J.F.L. acknowledges a fellowship from Boston University Innovation Center-BUnano Cross-Disciplinary Training in Nanotechnology for Cancer (XTNC). I.S acknowledges NSF support (grant CBET 1605405) and NIH R41AI142890.

All animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) at Boston University School of Medicine under the protocol #: PROTO201800543.
1. Generation of Casper zebrafish embryos
<ol>
	<li>Choose adult Casper fish that are at least 3 months of age for natural breeding to generate transparent Casper zebrafish embryos.</li>
	<li>Fill two-chamber mating tanks with fish water in the evening, separate the upper tanks using dividers, place one male fish into one side of the chamber and one or two female fish into the other side of the chamber, and leave the fish separated overnight by dividers.</li>
	<li>Pull out the dividers the next morning at 8:00 AM when the lights are on. Add artificial enrichment plants and tilt the top chamber slightly to create a shallow area of water. Allow the fish to breed for 3-4 h.</li>
	<li>Lift the top chambers of the mating tanks that contain the fish and return them to their original tanks.</li>
	<li>Collect eggs located in the bottom chambers by pouring the water through a mesh net. Transfer eggs to a sterile Petri dish at a density no greater than 200 eggs per dish. Remove any dead or unfertilized eggs and fill the dish 2/3 full with fresh fish water. 
	NOTE: Fertilized and healthy eggs should be translucent and round. Any eggs that are cloudy, white, or disfigured should be removed. Fish water is obtained from fish tanks in the fish facility.</li>
	<li>Incubate embryos in the incubator at 28.5 &#176;C overnight.</li>
	<li>Bleach the embryos the next morning using the standard protocol as described in The Zebrafish Book16, and put the embryos back to the incubator (optional step).</li>
	<li>Take the 24 hpf embryos out of the incubator in the afternoon and dechorionate the embryos using pronase.
	<ol>
		<li>Remove as much fish water as possible from the embryos in the Petri dish and add a few drops of the pronase solution (1 mg/mL in fish water) to the dish. Gently swirl the Petri dish. Once the chorions show signs of disintegration, pipette the embryos up and down a few times to break down the chorions to release the embryos.</li>
		<li>Add fresh fish water immediately into the Petri dish to terminate the process once a majority of the embryos are out of the chorions. Rinse the embryos 3x more using fish water to remove the floating chorions. Return the embryos to the incubator.</li>
	</ol>
	</li>
</ol>
2. Preparation of human cancer cells for transplantation
<ol>
	<li>Set the incubator temperature to exactly 35.5 &#176;C. Monitor the incubator to ensure a consistent and stable temperature using a thermometer inside the incubator.</li>
	<li>Autoclave 1 L of fish water in a glass bottle. Make a 3% agarose solution by adding 3 g of electrophoresis-grade agarose to 100 mL of autoclaved fish water and microwaving until the agarose is completely dissolved.
	<ol>
		<li>Pour hot agarose solution into a Petri dish until it is 3/4 full. Place the microinjection mold on the agarose. Ensure that the mold is not in contact with the bottom of the Petri dish and no bubbles form underneath.</li>
		<li>Allow the solution to solidify and carefully remove the mold from the plate. Fill the plate with autoclaved fish water and store the plate at 4 &#176;C. Prewarm the agarose plate and fish water in the 35.5 &#176;C incubator before harvesting HeLa cells.</li>
	</ol>
	</li>
	<li>Pull 1.0 mm O.D. x 0.78 mm borosilicate glass capillaries on a pipette puller using the following settings: pressure at 500, heat at 560, pull at 100, velocity at 100, and time/delay at 200. Store needles on putty in a large Petri dish that has been wiped with an ethanol towel. 
	CAUTION: Pulled needles are very sharp and fragile. Use caution when handling.</li>
	<li>Prepare a stock solution of tricaine methanesulfonate (MS222, 4 mg/mL) by dissolving MS222 into autoclaved fish water. Vortex well before use. Dilute MS222 stock solution 1:100 in fish water (i.e., add 200 &#181;L of MS222 stock solution to 20 mL of fish water to a final concentration of 40 &#181;g/mL) to anesthetize embryos for the following procedures.</li>
	<li>Culture hLabel HeLa cells by transducing them with PLenti6.2_miRFP670 lentivirus using the protocol described17. Harvest RFP+ HeLa cells 30 min-1 h before the transplantation. 
	NOTE: Human HeLa cells have been cultured in a tissue culture incubator up to 70% confluency in complete growth medium (DMEM medium with 10% FBS) at 37 &#176;C supplemented with 5% CO2.
	<ol>
		<li>Remove the HeLa cell medium by aspiration in a tissue culture hood. Briefly rinse the cell layer with sterile PBS to remove all traces of the serum.</li>
		<li>Add 3.0 mL of sterile Trypsin-EDTA solution to a T-75 flask and place the cells back into the 37 &#176;C tissue culture incubator for 3-5 min to facilitate enzymatic digestion. Observe the flask under the microscope until ~80% of the cells become suspended.</li>
		<li>Add 6-8 mL of complete growth medium into the flask. Collect the cells into a 15 mL sterile tube by gently pipetting. Centrifuge at 135 x g for 5 min.</li>
		<li>Aspirate the supernatant and resuspend HeLa cells in 3 mL of complete growth medium. Repeat the above washing step 2x. Resuspend the cells in 1 mL of complete growth medium and count the cells under the microscope using a hemocytometer.</li>
		<li>Spin the cells down again, remove the supernatant, and resuspend the cells in a 1.5 mL microcentrifuge tube at a concentration of 5 x 107 cells/mL. Keep the cells warm by holding the tube in one hand when transporting to the fish facility. 
		NOTE: Always keep the cells warm by storing the cells inside the 35.5 &#176;C incubator before or during injecting the embryos.</li>
	</ol>
	</li>
</ol>
3. Transplantation of human cancer cells
<ol>
	<li>Clean up the work area using ethanol towels before transplantation (e.g., scissors, tweezers, plastic pipettes, razor blades).</li>
	<li>Align embryos within the grooves of the agarose plate using a plastic pipette. Lay embryos on the side with the anterior facing forward. 
	NOTE: Make sure that the fish water covers the embryos. Set some embryos aside to not inject cancer cells and use as controls.</li>
	<li>Turn on the air source and microinjector. Take HeLa cells out of the incubator and pipette the cells up and down 20-30x using a P200 tip. Load 3 &#181;L of cell mixture immediately into a needle using a gel loading tip with a cut end. Carefully insert the tip toward the sharp bottom end of the needle. If needed, shake the needle to ensure the cell mixture moves down the needle to fill up the sharp end.
	<ol>
		<li>Insert the needle into the needle holder. Use a pair of tweezers to carefully break open the tip of the needle. Adjust the pressure and duration of time on the microinjector to push out all of the air bubbles inside the needle tip. Reduce the pressure and injection duration time until the size of the injection droplets is ~1 nL.</li>
		<li>Place the injection plate under the microscope in an appropriate position to have the yolk side of embryos facing the needle. Anesthetize the embryos by adding five drops of the diluted MS222 solution (40 &#181;g/mL).</li>
		<li>Position the injector and allow the needle to touch the perivitelline cavity of each embryo.</li>
	</ol>
	</li>
	<li>Inject the cell mixture into the embryos at the vascularized area under the perivitelline cavity by pressing the foot pedal.</li>
	<li>Use the nondominant hand to move the injection plate to the next embryo. Use the dominant hand to extend and retract the injector while pressing the foot pedal simultaneously to continue the injection. Pipette a few drops of sterile fish water onto embryos that have been injected. Once the injection of all embryos on the plate is completed, wash the embryos off with sterile fish water, put them on a sterile Petri dish and immediately move them to the 35.5 &#176;C incubator.</li>
	<li>After 3 h, examine the injected embryos and remove the dead ones.</li>
	<li>Return the live embryos to the 35.5 &#176;C incubator and incubate them for 20-24 h to allow the HeLa cells to spread from the injection site to other parts of the body. 
	NOTE: Embryos are kept in 35.5 &#176;C incubator to allow the survival and migration of human cancer cells because the cells do not do well at 28.5 &#176;C, the temperature fish embryos are normally incubated.</li>
</ol>
4. Injection of nanoparticles or vehicle
<ol>
	<li>Anesthetize the transplanted embryos the next morning with five drops of diluted MS222 solution. Do not to add too much MS222, because this will kill the embryos. Under a fluorescent microscope, carefully pick up embryos with tail metastasis of RFP+ HeLa cells and place them into a new Petri dish with sterile fish water.</li>
	<li>Make the injection needles as previously described in section 2 using the following settings: pressure at 500, heat at 645, pull at 60, velocity at 50, and time/delay at 100.</li>
	<li>Follow the procedures in steps 3.1-3.3 to align embryos and load vehicle (e.g., H2O) or the nanoparticle solution into the needle.</li>
	<li>Inject 0.5 nL of 1 mg/mL nanoparticle solution behind the eye and continue the injection as described in steps 3.5-3.6 (Figure 1B). This location behind the eyes is enriched with capillaries, allowing the nanoparticles to enter circulation.</li>
	<li>Following a similar procedure, inject the vehicle (e.g., H2O) that was used to suspend the nanoparticles into embryos with HeLa cells transplanted and those without (i.e., controls) (Figure 1A, C).</li>
	<li>Incubate all injected embryos at 35.5 &#176;C.</li>
</ol>
5. Imaging and tracking of nanoparticles and cancer cells
<ol>
	<li>Examine injected embryos under a fluorescent microscope at 0, 30, 60, 90, 120, 180, and 210 min postinjection of nanoparticles to monitor their distribution in circulation and the degree of cancer cell targeting. The targeting of cancer cells by nanoparticles can be observed as early as 30 min postinjection depending on the type of nanoparticle tested.</li>
	<li>Pipette 2-3 embryos into a Petri dish and immobilize them by adding five drops of diluted MS222 solution (40 &#181;g/mL). Once the embryos stop swimming, remove most of the water to allow the embryos to lie on their sides.</li>
	<li>Use a pipette with a thin, soft brush attached to its end to align the embryos so they lie on their sides with the anterior facing forward and only one eye visible.</li>
	<li>Image the embryos in red, blue, and brightfield channels at low magnification (2x) to capture the whole embryo and repeat at higher magnification (6.4x) to capture the tail area. Focus the embryo under the red channel to avoid the bleeding of nanoparticles. 
	NOTE: The embryos must not move during imaging. Any movement will lead to blurry images and the inability to overlap images from different channels.</li>
	<li>Add fresh fish water to the embryos immediately after imaging and return them to the incubator. Repeat steps 5.2-5.4 to image the embryos at different time points.</li>
</ol>

<ol>
	<li>Dadwal, A., Baldi, A., Kumar Narang, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticles+as+carriers+for+drug+delivery+in+cancer.">Nanoparticles as carriers for drug delivery in cancer.</a> Artificial Cells, Nanomedicine, Biotechnology. 46 (Suppl 2), 295-305 (2018).</li><li>Cho, K., Wang, X., Nie, S., Chen, Z. G., Shin, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapeutic+nanoparticles+for+drug+delivery+in+cancer.">Therapeutic nanoparticles for drug delivery in cancer.</a> Clinical Cancer Research. 14 (5), 1310-1316 (2008).</li><li>Senapati, S., Mahanta, A. K., Kumar, S., Maiti, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+drug+delivery+vehicles+for+cancer+treatment+and+their+performance.">Controlled drug delivery vehicles for cancer treatment and their performance.</a> Signal Transduction and Target Therapy. 3, 7 (2018).</li><li>Chinen, 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=Nanoparticle+Probes+for+the+Detection+of+Cancer+Biomarkers,+Cells,+and+Tissues+by+Fluorescence.">Nanoparticle Probes for the Detection of Cancer Biomarkers, Cells, and Tissues by Fluorescence.</a> Chemal Reviews. 115 (19), 10530-10574 (2015).</li><li>Palantavida, S., Guz, N. V., Woodworth, C. D., Sokolov, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrabright+fluorescent+mesoporous+silica+nanoparticles+for+prescreening+of+cervical+cancer.">Ultrabright fluorescent mesoporous silica nanoparticles for prescreening of cervical cancer.</a> Nanomedicine. 9 (8), 1255-1262 (2013).</li><li>Singh, M., Murriel, C. L., Johnson, L. <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:+closing+the+gap+between+preclinical+data+and+trial+outcomes.">Genetically engineered mouse models: closing the gap between preclinical data and trial outcomes.</a> Cancer Research. 72 (11), 2695-2700 (2012).</li><li>Sharkey, F. E., Fogh, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+in+the+use+of+nude+mice+for+cancer+research.">Considerations in the use of nude mice for cancer research.</a> Cancer Metastasis Reviews. 3 (4), 341-360 (1984).</li><li>Vargo-Gogola, T., Rosen, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+breast+cancer:+one+size+does+not+fit+all.">Modelling breast cancer: one size does not fit all.</a> Nature Reviews Cancer. 7 (9), 659-672 (2007).</li><li>Minn, A. 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=Genes+that+mediate+breast+cancer+metastasis+to+lung.">Genes that mediate breast cancer metastasis to lung.</a> Nature. 436 (7050), 518-524 (2005).</li><li>Soares, K. 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=A+preclinical+murine+model+of+hepatic+metastases.">A preclinical murine model of hepatic metastases.</a> Journal of Visualized Experiments. (91), e51677 (2014).</li><li>Etchin, J., Kanki, J. P., Look, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+as+a+model+for+the+study+of+human+cancer.">Zebrafish as a model for the study of human cancer.</a> Methods in Cell Biology. 105, 309-337 (2011).</li><li>Liu, S., Leach, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+models+for+cancer.">Zebrafish models for cancer.</a> Annual Reviews in Pathology. 6, 71-93 (2011).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Developmental Dynamics. 203 (3), 253-310 (1995).</li><li>White, R. 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=Transparent+adult+zebrafish+as+a+tool+for+in+vivo+transplantation+analysis.">Transparent adult zebrafish as a tool for in vivo transplantation analysis.</a> Cell Stem Cell. 2 (2), 183-189 (2008).</li><li>Lam, S. H., Chua, H. L., Gong, Z., Lam, T. J., Sin, Y. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+maturation+of+the+immune+system+in+zebrafish,+Danio+rerio:+a+gene+expression+profiling,+in+situ+hybridization+and+immunological+study.">Development and maturation of the immune system in zebrafish, Danio rerio: a gene expression profiling, in situ hybridization and immunological study.</a> Developmental and Comparative Immunology. 28 (1), 9-28 (2004).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> THE ZEBRAFISH BOOK. , (2007).</li><li>Anderson, N. 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+TCA+cycle+transferase+DLST+is+important+for+MYC-mediated+leukemogenesis.">The TCA cycle transferase DLST is important for MYC-mediated leukemogenesis.</a> Leukemia. 30 (6), 1365-1374 (2016).</li><li>Peerzade, 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=Ultrabright+fluorescent+silica+nanoparticles+for+in+vivo+targeting+of+xenografted+human+tumors+and+cancer+cells+in+zebrafish.">Ultrabright fluorescent silica nanoparticles for in vivo targeting of xenografted human tumors and cancer cells in zebrafish.</a> Nanoscale. 11 (46), 22316-22327 (2019).</li><li>Peng, 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=Ultrabright+fluorescent+cellulose+acetate+nanoparticles+for+imaging+tumors+through+systemic+and+topical+applications.">Ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications.</a> Materials Today (Kidlington). 23, 16-25 (2019).</li><li>Peng, 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=Data+on+ultrabright+fluorescent+cellulose+acetate+nanoparticles+for+imaging+tumors+through+systemic+and+topical+applications.">Data on ultrabright fluorescent cellulose acetate nanoparticles for imaging tumors through systemic and topical applications.</a> Data in Brief. 22, 383-391 (2019).</li><li>Masters, J. R., Stacey, G. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changing+medium+and+passaging+cell+lines.">Changing medium and passaging cell lines.</a> Nature Protocols. 2 (9), 2276-2284 (2007).</li><li>Rao, P. N., Engelberg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hela+Cells:+Effects+of+Temperature+on+the+Life+Cycle.">Hela Cells: Effects of Temperature on the Life Cycle.</a> Science. 148 (3673), 1092-1094 (1965).</li><li>Avdesh, 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=Regular+care+and+maintenance+of+a+zebrafish+(Danio+rerio)+laboratory:+an+introduction.">Regular care and maintenance of a zebrafish (Danio rerio) laboratory: an introduction.</a> Journal of Visualized Experiments. (69), e4196 (2012).</li><li>Spence, R., Gerlach, G., Lawrence, C., Smith, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+behaviour+and+ecology+of+the+zebrafish,+Danio+rerio.">The behaviour and ecology of the zebrafish, Danio rerio.</a> Biological Reviews of the Cambridge Philosophical Society. 83 (1), 13-34 (2008).</li></ol>

I.S. declares interest in NanoScience Solutions, LLC (recipient of STTR NIH R41AI142890 grant). All other authors declare no conflicts of interest.

The protocol described here utilizes the zebrafish as an in vivo system to test the ability of nanoparticles to recognize and target metastatic human cancer cells. Several factors can impact the successful execution of the experiments. First, embryos need to be fully developed at 48 hpf. The correct developmental stage of the embryos enables them to endure and survive the transplantation of human cancer cells. Embryos younger than 48 hpf have a significantly lower survival rate compared to older and more developed embryo...

The development of nanoparticles that are capable of detecting, targeting, and destroying cancer cells is of great interest to both physicists and biomedical researchers. The emergence of nanomedicine led to the development of several nanoparticles, such as those conjugated with targeting ligands and/or chemotherapeutic drugs1,2,3. The added properties of nanoparticles enable their interaction with the biological system, sensing and monitoring biological events with high efficiency and accuracy along with therapeutic applications. Gold and iron oxide nanoparticles are primarily used in computed tomography and magnetic resonance imaging applications, respectively. While the enzymatic activities of gold and iron oxide nanoparticles allow the detection of cancer cells through colorimetric assays, fluorescent nanoparticles are well suited for in vivo imaging applications4. Among them, ultrabright fluorescent nanoparticles are particularly beneficial, due to their ability to detect cancers early with fewer particles and reduced toxicities5.
Despite these advantages, nanoparticles require experimentation using in vivo animal models for the selection of suitable nanomaterials and optimization of the synthesis process. Additionally, just like drugs, nanoparticles rely on animal models for preclinical testing to determine their efficacy and toxicities. The most widely used preclinical model is the mouse, which is a mammal whose upkeep comes at a relatively high cost. For cancer studies, either genetically engineered mice or xenografted mice are typically used6,7. The length of these experiments often spans from weeks to months. In particular, for cancer metastasis studies, cancer cells are directly injected into the circulatory system of the mice at locations such as tail veins and spleens8,9,10. These models only represent the end stages of metastasis when tumor cells extravasate and colonize distant organs. Moreover, due to visibility issues, it is particularly challenging to monitor tumor cell migration and nanoparticle targeting of tumor cells in mice.
The zebrafish (Danio rerio) has become a powerful vertebrate system for cancer research due to its high fecundity, low cost, rapid development, optical transparency, and genetic conservations11,12. Another advantage of the zebrafish over the mouse model is the fertilization of the fish eggs ex utero, which allows the embryos to be monitored throughout their development. Embryonic development is rapid in zebrafish, and within 24 hours postfertilization (hpf), the vertebrate body plane has already formed13. By 72 hpf, eggs are hatched from the chorion, transitioning from the embryonic to the fry stage. The transparency of the zebrafish, the Casper strain in particular14, provides a unique opportunity to visualize the migration of cancer cells and their recognition and targeting by nanoparticles in a living animal. Finally, zebrafish develop their innate immune system by 48 hpf, with the adaptive immune system lagging behind and only becoming functional at 28 days postfertilization15. This time gap is ideal for the transplantation of various types of human cancer cells into zebrafish embryos without experiencing immune rejections.
Described here is a method that takes advantage of the transparency and rapid development of zebrafish to demonstrate the recognition and targeting of human cancer cells by fluorescent nanoparticles in vivo. In this assay, human cervical cancer cells (HeLa cells) genetically engineered to express a red fluorescent protein were injected into the vascularized area in the perivitelline cavity of 48 hpf embryos. After 20-24 h, HeLa cells had already spread throughout the embryos through the fish circulatory system. Embryos with apparent metastasis were microinjected with ~0.5 nL of a nanoparticle solution directly behind the eye, where the rich capillary bed is located. Using this technique, the ultrabright fluorescent silica nanoparticles can target HeLa cells as quickly as 20-30 min postinjection. Due to its simplicity and effectiveness, the zebrafish represents a robust in vivo model to test a variety of nanoparticles for their ability to target specific cancer cells.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Agarose</td>
			<td>KSE scientific</td>
			<td>BMK-A1705</td>
			<td></td>
		</tr>
		<tr>
			<td>Borosilicate glass capillaries</td>
			<td>World Precision Instruments</td>
			<td>1.0 mm O.D. x 0,78 mm</td>
			<td></td>
		</tr>
		<tr>
			<td>Computer and monitor</td>
			<td>ThinkCentre</td>
			<td>X000335</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM (Dulbecco&#39;s Modified Eagle&#39;s Medium)</td>
			<td>Corning</td>
			<td>10-013-CV</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Sigma-Aldrich</td>
			<td>F0926</td>
			<td></td>
		</tr>
		<tr>
			<td>Fish incubator</td>
			<td>VWR</td>
			<td>35960-056</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>Fishersci brand</td>
			<td>02-671-51B</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic stand</td>
			<td>World Precision Instruments</td>
			<td>M10</td>
			<td></td>
		</tr>
		<tr>
			<td>Microloader tip</td>
			<td>Eppendorf</td>
			<td>E5242956003</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Applied Scientific Instrumentation</td>
			<td>MMPI-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle Puller</td>
			<td>Sutter instruments</td>
			<td>P-97</td>
			<td></td>
		</tr>
		<tr>
			<td>Olympus MVX-10 fluorescent microscope</td>
			<td>Olympus</td>
			<td>MVX-10</td>
			<td></td>
		</tr>
		<tr>
			<td>P200 tip</td>
			<td>Fishersci brand</td>
			<td><a href="https://www.fishersci.com/shop/products/corning-universal-fit-pipet-tips-bulk-packed-6/07200293?keyword=true" target="_blank">07-200-293</a></td>
			<td></td>
		</tr>
		<tr>
			<td>PBS (Dulbecco&#39;s Phosphate-Buffered Salt Solution 1X)</td>
			<td>Corning</td>
			<td>21-030-CV</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>Corning</td>
			<td>SB93102</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Plastic pipette</td>
			<td>Fishersci brand</td>
			<td>50-998-100</td>
			<td></td>
		</tr>
		<tr>
			<td><a href="https://www.addgene.org/113726/" target="_blank">pLenti6.2_miRFP670</a></td>
			<td>Addgene</td>
			<td>13726</td>
			<td></td>
		</tr>
		<tr>
			<td>Pneumatic pico pump</td>
			<td>World Precision Instruments</td>
			<td>SYSPV820</td>
			<td></td>
		</tr>
		<tr>
			<td>Pronase</td>
			<td>Roche-Sigma-Fisher</td>
			<td>50-100-3275</td>
			<td>Roche product made by Sigma- sold by Fisher</td>
		</tr>
		<tr>
			<td>Razor blade</td>
			<td>Fishersci brand</td>
			<td>12-640</td>
			<td></td>
		</tr>
		<tr>
			<td>SZ51 dissection microscope</td>
			<td>Olympus</td>
			<td>SZ51</td>
			<td></td>
		</tr>
		<tr>
			<td>Tricaine methanesulfonate</td>
			<td>Western Chemicals</td>
			<td>NC0872873</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Corning</td>
			<td>MT25053CI</td>
			<td>sold by Fisher</td>
		</tr>
		<tr>
			<td>Tweezer</td>
			<td>Fishersci brand</td>
			<td>12-000-122</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vivo targeting of xenografted human cancer cells with functionalized fluorescent silica nanoparticles in zebrafish

Developing nanoparticles capable of detecting, targeting, and destroying cancer cells is of great interest in the field of nanomedicine. In vivo animal models are required for bridging the nanotechnology to its biomedical application. The mouse represents the traditional animal model for preclinical testing; however, mice are relatively expensive to keep and have long experimental cycles due to the limited progeny from each mother. The zebrafish has emerged as a powerful model system for developmental and biomedical research, including cancer research. In particular, due to its optical transparency and rapid development, zebrafish embryos are well suited for real-time in vivo monitoring of the behavior of cancer cells and their interactions with their microenvironment. This method was developed to sequentially introduce human cancer cells and functionalized nanoparticles in transparent Casper zebrafish embryos and monitor in vivo recognition and targeting of the cancer cells by nanoparticles in real time. This optimized protocol shows that fluorescently labeled nanoparticles, which are functionalized with folate groups, can specifically recognize and target metastatic human cervical epithelial cancer cells labeled with a different fluorochrome. The recognition and targeting process can occur as early as 30 min postinjection of the nanoparticles tested. The whole experiment only requires the breeding of a few pairs of adult fish and takes less than 4 days to complete. Moreover, zebrafish embryos lack a functional adaptive immune system, allowing the engraftment of a wide range of human cancer cells. Hence, the utility of the protocol described here enables the testing of nanoparticles on various types of human cancer cells, facilitating the selection of optimal nanoparticles in each specific cancer context for future testing in mammals and the clinic.

The protocol schematic in Figure 1&#160;illustrates the overall procedures for this study. Transparent Casper male and female adult fish were bred to generate embryos (section 1). RFP+ HeLa cells were injected into the vascularized area under the perivitelline cavity of the zebrafish embryos at 48 hpf, with uninjected embryos as controls (section 3). For individuals experienced in microinjection, the survival rate of embryos is often high, with at le...

Watch this Scientific Journal Video about In Vivo Targeting of Xenografted Human Cancer Cells with Functionalized Fluorescent Silica Nanoparticles in Zebrafish at JoVE.com

In Vivo Targeting of Xenografted Human Cancer Cells with Functionalized Fluorescent Silica Nanoparticles in Zebrafish

Described here is a method for utilizing zebrafish embryos to study the ability of functionalized nanoparticles to target human cancer cells in vivo. This method allows for the evaluation and selection of optimal nanoparticles for future testing in large animals and in clinical trials.

Developing nanoparticles capable of detecting, targeting, and destroying cancer cells is of great interest in the field of nanomedicine. In vivo animal ...

in-vivo-targeting-xenografted-human-cancer-cells-with-functionalized

Research

JoVE Journal

Cancer Research

4.5K Views.  Boston University School of Medicine. Described here is a method for utilizing zebrafish embryos to study the ability of functionalized nanoparticles to target human cancer cells in vivo. This method allows for the evaluation and selection of optimal nanoparticles for future testing in large animals and in clinical trials.

Video: In Vivo Targeting of Xenografted Human Cancer Cells with Functionalized Fluorescent Silica Nanoparticles in Zebrafish

Invasive Behavior of Human Breast Cancer Cells in Embryonic Zebrafish

In many cases, cancer patients do not die of a primary tumor, but rather because of metastasis. Although numerous rodent models are available for studying cancer metastasis in vivo, other efficient, reliable, low-cost models are needed to quickly access the potential effects of (epi)genetic changes or pharmacological compounds. As such, we illustrate and explain the feasibility of xenograft models using human breast cancer cells injected into zebrafish embryos to support this goal. Under the microscope, fluorescent proteins or chemically labeled human breast cancer cells are transplanted into transgenic zebrafish embryos, Tg (fli:EGFP), at the perivitelline space or duct of Cuvier (Doc) 48 h after fertilization. Shortly afterwards, the temporal-spatial process of cancer cell invasion, dissemination, and metastasis in the living fish body is visualized under a fluorescent microscope. The models using different injection sites, i.e., perivitelline space or Doc are complementary to one another, reflecting the early stage (intravasation step) and late stage (extravasation step) of the multistep metastatic cascade of events. Moreover, peritumoral and intratumoral angiogenesis can be observed with the injection into the perivitelline space. The entire experimental period is no more than 8 days. These two models combine cell labeling, micro-transplantation, and fluorescence imaging techniques, enabling the rapid evaluation of cancer metastasis in response to genetic and pharmacological manipulations.

Here, we describe xenograft zebrafish models using two different injection sites, i.e., perivitelline space and duct of Cuvier, to investigate the invasive behavior and to assess the intravasation and extravasation potential of human breast cancer cells, respectively.

In many cases, cancer patients do not die of a primary tumor, but rather because of metastasis. Although numerous rodent models are available for studying ...

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 ...

Synthesis and Characterization of Placental Chondroitin Sulfate A (plCSA)-Targeting Lipid-Polymer Nanoparticles

An effective cancer therapeutic method reduces and eliminates tumors with minimal systemic toxicity. Actively targeting nanoparticles offer a promising approach to cancer therapy. The glycosaminoglycan placental chondroitin sulfate A (plCSA) is expressed on a wide range of cancer cells and placental trophoblasts, and malarial protein VAR2CSA can specifically bind to plCSA. A reported placental chondroitin sulfate A binding peptide (plCSA-BP), derived from malarial protein VAR2CSA, can also specifically bind to plCSA on cancer cells and placental trophoblasts. Hence, plCSA-BP-conjugated nanoparticles could be used as a tool for targeted drug delivery to human cancers and placental trophoblasts. In this protocol, we describe a method to synthesize plCSA-BP-conjugated lipid-polymer nanoparticles loaded with doxorubicin (plCSA-DNPs); the method consists of a single sonication step and bioconjugate techniques. In addition, several methods for characterizing plCSA-DNPs, including determining their physicochemical properties and cellular uptake by placental choriocarcinoma (JEG3) cells, are described.

Synthesis and Characterization of Placental Chondroitin Sulfate A plCSA-Targeting Lipid-Polymer Nanoparticles

Here, we present a protocol for the synthesis of placental chondroitin sulfate A binding peptide (plCSA-BP)-conjugated lipid-polymer nanoparticles via single-step sonication and bioconjugate techniques. These particles constitute a novel tool for the targeted delivery of therapeutics to most human tumors and placental trophoblasts to treat cancers and placental disorders.

An effective cancer therapeutic method reduces and eliminates tumors with minimal systemic toxicity. Actively targeting nanoparticles offer a promising ...

In Vitro Evaluation of Oncogenic Transformation in Human Mammary Epithelial Cells

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile conditions. Different tests seek to identify and quantify these hallmarks of cancerous cells; however, they often focus on a single aspect of cellular transformation and, in fact, multiple tests are required for their proper characterization. The purpose of this work is to provide researchers with a set of tools to assess cellular transformation in vitro from a broad perspective, thereby making it possible to draw sound conclusions.
A sustained proliferative signaling activation is the major feature of tumoral tissues and can be easily monitored under in vitro conditions by calculating the number of population doublings achieved over time. Besides, the growth of cells in 3D cultures allows their interaction with surrounding cells, resembling what occurs in vivo. This enables the evaluation of cellular aggregation and, together with immunofluorescent labeling of distinctive cellular markers, to obtain information on another relevant feature of tumoral transformation: the loss of proper organization. Another remarkable characteristic of transformed cells is their capacity to grow without attachment to other cells and to the extracellular matrix, which can be evaluated with the anchorage assay.
Detailed experimental procedures to evaluate cell growth rate, to perform immunofluorescent labeling of cell lineage markers in 3D cultures, and to test anchorage-independent cell growth in soft agar are provided. These methodologies are optimized for Breast Primary Epithelial Cells (BPEC) due to its relevance in breast cancer; however, procedures can be applied to other cell types after some adjustments.

This protocol provides experimental in vitro tools to evaluate the transformation of human mammary cells. Detailed steps to follow-up cell proliferation rate, anchorage-independent growth capacity, and distribution of cell lineages in 3D cultures with basement membrane matrix are described.

Tumorigenesis is a multi-step process in which cells acquire capabilities&#160;that allow their growth, survival, and dissemination under hostile ...

Chemical Conjugation of a Purified DEC-205-Directed Antibody with Full-Length Protein for Targeting Mouse Dendritic Cells In Vitro and In Vivo

Targeted antigen delivery to cross-presenting dendritic cells (DC) in vivo efficiently induces T effector cell responses and displays a valuable approach in&#160;vaccine design. Antigen is delivered to DC via antibodies specific for endocytosis receptors such as DEC-205 that induce uptake, processing, and MHC class I- and II-presentation.
Efficient and reliable conjugation of the desired antigen to a suitable antibody is a critical step in DC targeting and among other factors depends on the format of the antigen. Chemical conjugation of&#160;full-length protein to purified antibodies is one possible strategy. In the past, we have successfully established cross-linking of the model antigen ovalbumin (OVA) and a DEC-205-specific IgG2a antibody (&#945;DEC-205)&#160;for in vivo DC targeting studies in mice. The first step of the protocol is the purification of the antibody from the supernatant of the NLDC (non-lymphoid dendritic cells)-145 hybridoma by affinity chromatography. The purified antibody is activated for chemical conjugation by sulfo-SMCC (sulfosuccinimidyl 4-[N-maleimidomethyl] cyclohexane-1-carboxylate) while at the same time the sulfhydryl-groups of the OVA protein are exposed through incubation with TCEP-HCl (tris (2-carboxyethyl) phosphine hydrochloride). Excess TCEP-HCl and sulfo-SMCC are removed and the antigen is mixed with the activated antibody for overnight coupling. The resulting &#945;DEC-205/OVA conjugate is concentrated and freed from unbound OVA. Successful conjugation of OVA to &#945;DEC-205 is verified by western blot analysis and enzyme-linked immunosorbent assay (ELISA).
We have successfully used chemically crosslinked &#945;DEC-205/OVA to induce cytotoxic T cell responses in the liver and to compare different adjuvants for their potential in inducing humoral and cellular immunity following in vivo targeting of DEC-205+ DC. Beyond that, such chemically coupled antibody/antigen conjugates offer valuable tools for the efficient induction of vaccine responses to tumor antigens and have been proven to be superior to classical immunization approaches regarding the prevention and therapy of various types of tumors.

Chemical Conjugation of a Purified DEC-205-Directed Antibody with Full-Length Protein for Targeting Mouse Dendritic Cells In Vitro and In Vivo

We describe a protocol for the chemical conjugation of the model antigen ovalbumin to an endocytosis receptor-specific antibody for in vivo dendritic cell targeting. The protocol includes purification of the antibody, chemical conjugation of the antigen, as well as purification of the conjugate and the verification of efficient conjugation.

Targeted antigen delivery to cross-presenting dendritic cells (DC) in vivo efficiently induces T effector cell responses and displays a valuable approach ...

Evaluation of the In vivo Antitumor Activity of Polyanhydride IL-1&#945; Nanoparticles

Cytokine therapy is a promising immunotherapeutic strategy that can produce robust antitumor immune responses in cancer patients. The proinflammatory cytokine interleukin-1 alpha (IL-1&#945;) has been evaluated as an anticancer agent in several preclinical and clinical studies. However, dose-limiting toxicities, including flu-like symptoms and hypotension, have dampened the enthusiasm for this therapeutic strategy. Polyanhydride nanoparticle (NP)-based delivery of IL-1&#945; would represent an effective approach in this context since this may allow for a slow and controlled release of IL-1&#945; systemically while reducing toxic side effects. Here an analysis of the antitumor activity of IL-1&#945;-loaded polyanhydride NPs in a head and neck squamous cell carcinoma (HNSCC) syngeneic mouse model is described. Murine oropharyngeal epithelial cells stably expressing HPV16 E6/E7 together with hRAS and luciferase (mEERL) cells were injected subcutaneously into the right flank of C57BL/6J mice. Once tumors reached 3-4 mm in any direction, a 1.5% IL-1a - loaded 20:80 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane:1,6-bis(p-carboxyphenoxy)hexane (CPTEG: CPH) nanoparticle (IL-1&#945;-NP) formulation was administered to mice intraperitoneally. Tumor size and body weight were continuously measured until tumor size or weight loss reached euthanasia criteria. Blood samples were taken to evaluate antitumor immune responses by submandibular venipuncture, and inflammatory cytokines were measured through cytokine multiplex assays. Tumor and inguinal lymph nodes were resected and homogenized into a single-cell suspension to analyze various immune cells through multicolor flow cytometry. These standard methods will allow investigators to study the antitumor immune response and potential mechanism of immunostimulatory NPs and other immunotherapy agents for cancer treatment.

Evaluation of the In vivo Antitumor Activity of Polyanhydride IL-1&#945; Nanoparticles

A standard protocol is described to study the antitumor activity and associated toxicity of IL-1&#945; in a syngeneic mouse model of HNSCC.

Cytokine therapy is a promising immunotherapeutic strategy that can produce robust antitumor immune responses in cancer patients. The proinflammatory ...

Fluorescence Microscopy for ATP Internalization Mediated by Macropinocytosis in Human Tumor Cells and Tumor-xenografted Mice

Adenosine triphosphate (ATP), including extracellular ATP (eATP), has been shown to play significant roles in various aspects of tumorigenesis, such as drug resistance, epithelial-mesenchymal transition (EMT), and metastasis. Intratumoral eATP is 103 to 104 times higher in concentration than in normal tissues. While eATP functions as a messenger to activate purinergic signaling for EMT induction, it is also internalized by cancer cells through upregulated macropinocytosis, a specific type of endocytosis, to perform a wide variety of biological functions. These functions include providing energy to ATP-requiring biochemical reactions, donating phosphate groups during signal transduction, and facilitating or accelerating gene expression as a transcriptional cofactor. ATP is readily available, and its study in cancer and other fields will undoubtedly increase. However, eATP study remains at an early stage, and unresolved questions remain unanswered before the important and versatile activities played by eATP and internalized intracellular ATP can be fully unraveled.
These authors&#39; laboratories&#39; contributions to these early eATP studies include microscopic imaging of non-hydrolysable fluorescent ATP, coupled with high- and low-molecular weight fluorescent dextrans, which serve as macropinocytosis and endocytosis tracers, as well as various endocytosis inhibitors, to monitor and characterize the eATP internalization process. This imaging modality was applied to tumor cell lines and to immunodeficient mice, xenografted with human cancer tumors, to study eATP internalization in vitro and in vivo. This paper describes these in vitro and in vivo protocols, with an emphasis on modifying and finetuning assay conditions so that the macropinocytosis-/endocytosis-mediated eATP internalization assays can be successfully performed in different systems.

We developed a reproducible method to visualize the internalization of nonhydrolyzable fluorescent adenosine triphosphate (ATP), an ATP surrogate, with high cellular resolution. We validated our method using independent in vitro and in vivo assays-human tumor cell lines and immunodeficient mice xenografted with human tumor tissue.

Adenosine triphosphate (ATP), including extracellular ATP (eATP), has been shown to play significant roles in various aspects of tumorigenesis, such as ...

Simultaneous Imaging and Flow-Cytometry-based Detection of Multiple Fluorescent Senescence Markers in Therapy-Induced Senescent Cancer Cells

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, senescence is a fundamentally different machinery restraining&#160;propagation of cancer cells. Decades of scientific studies have revealed the complex pathological effects of senescent cancer cells in tumors and microenvironments that modulate cancer cells and stromal cells. New evidence suggests that senescence is a potent prognostic factor during cancer treatment, and therefore rapid and accurate detection of senescent cells in cancer samples is essential. This paper presents a method to visualize and detect therapy-induced senescence (TIS) in cancer cells. Diffuse large B-cell lymphoma (DLBCL) cell lines were treated with mafosfamide (MAF) or daunorubicin (DN) and examined for the senescence marker, senescence-associated &#946;-galactosidase (SA-&#946;-gal), the DNA synthesis marker 5-ethynyl-2&#8242;-deoxyuridine (EdU), and the DNA damage marker gamma-H2AX (&#947;H2AX). Flow cytometer imaging can help generate high-resolution single-cell images in a short period of time to simultaneously visualize and quantify the three markers in cancer cells.

Here we present a flow cytometry-based method for visualization and quantification of multiple senescence-associated markers in single cells.

Chemotherapeutic drugs can induce irreparable DNA damage in cancer cells, leading to apoptosis or premature senescence. Unlike apoptotic cell death, ...

Establishment of Zebrafish Patient-Derived Xenografts from Pancreatic Cancer for Chemosensitivity Testing

Cancer is one of the main causes of death worldwide, and the incidence of many types of cancer continues to increase. Much progress has been made in terms of screening, prevention, and treatment; however, preclinical models that predict the chemosensitivity profile of cancer patients are still lacking. To fill this gap, an in vivo patient-derived xenograft model was developed and validated. The model was based on zebrafish (Danio rerio) embryos at 2 days post fertilization, which were used as recipients of xenograft fragments of tumor tissue taken from a patient's surgical specimen. 
It is also worth noting that bioptic samples were not digested or disaggregated, in order to maintain the tumor microenvironment, which is crucial in terms of analyzing tumor behavior and the response to therapy. The protocol details a method for establishing zebrafish-based patient-derived xenografts (zPDXs) from primary solid tumor surgical resection. After screening by an anatomopathologist, the specimen is dissected using a scalpel blade. Necrotic tissue, vessels, or fatty tissue are removed and then chopped into 0.3 mm x 0.3 mm x 0.3 mm pieces. 
The pieces are then fluorescently labeled and xenotransplanted into the perivitelline space of zebrafish embryos. A large number of embryos can be processed at a low cost, enabling high-throughput in vivo analyses of the chemosensitivity of zPDXs to multiple anticancer drugs. Confocal images are routinely acquired to detect and quantify the apoptotic levels induced by chemotherapy treatment compared to the control group. The xenograft procedure has a significant time advantage, since it can be completed in a single day, providing a reasonable time window to carry out a therapeutic screening for co-clinical trials.

Preclinical models aim to advance the knowledge of cancer biology and predict treatment efficacy. This paper describes the generation of zebrafish-based patient-derived xenografts (zPDXs) with tumor tissue fragments. The zPDXs were treated with chemotherapy, the therapeutic effect of which was assessed in terms of cell apoptosis of the transplanted tissue.

Cancer is one of the main causes of death worldwide, and the incidence of many types of cancer continues to increase. Much progress has been made in terms ...

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

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.

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.

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