Name: drug screening of primary patient derived tumor xenografts in zebrafish
Uploaded: 2020-04-10T14:00:00
Description: Watch this Scientific Journal Video about Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish at JoVE.com

This research was supported by a V Foundation V Scholar Award and NIH Grants DP2CA228043, R01CA227656 (to J.S. Blackburn) and NIH Training Grant T32CA165990 (to M.G. Haney).

All procedures described in this protocol have been approved by the University of Kentucky&#8217;s Institutional Animal Care and Use Committee (protocol 2015-2225). Patient samples were collected under University of Kentucky&#8217;s Institutional Review Board (protocol 44672). All animal experiments performed following this protocol must be approved by the user&#8217;s Institutional Animal Care and Use Committee.
1. Thawing Primary Patient Acute Lymphoblastic Leukemia Cells
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	<li>Thaw pr...

<ol>
	<li>Lee, L. M., Seftor, E. A., Bonde, G., Cornell, R. A., Hendrix, M. 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+fate+of+human+malignant+melanoma+cells+transplanted+into+zebrafish+embryos:+assessment+of+migration+and+cell+division+in+the+absence+of+tumor+formation.">The fate of human malignant melanoma cells transplanted into zebrafish embryos: assessment of migration and cell division in the absence of tumor formation.</a> Developmental Dynamics. 233 (4), 1560-1570 (2005).</li><li>Topczewska, J. 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P., 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=Automated+whole+animal+bio-imaging+assay+for+human+cancer+dissemination.">Automated whole animal bio-imaging assay for human cancer dissemination.</a> PLoS One. 7 (2), 31281 (2012).</li><li>Chang, T. -. Y. Y., Pardo-Martin, C., Allalou, A., W&#228;hlby, C., Yanik, M. 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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Zebrafish+Xenograft+Platform:+Evolution+of+a+Novel+Cancer+Model+and+Preclinical+Screening+Tool.">The Zebrafish Xenograft Platform: Evolution of a Novel Cancer Model and Preclinical Screening Tool.</a> Advances in Experimental Medicine and Biology. 916, 289-314 (2016).</li><li>Tang, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimized+cell+transplantation+using+adult+rag2+mutant+zebrafish.">Optimized cell transplantation using adult rag2 mutant zebrafish.</a> Nature Methods. 11 (8), 821-824 (2014).</li><li>Moore, J. 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In this study, we demonstrated a standardized method for thawing and injection of primary patient leukemia cells into zebrafish as a xenograft model. We also established a protocol for high-throughput drug screening of xenografted zebrafish using a fluorescence microscope equipped imaging unit and automated sampler unit. Previously, xenografts have been reported with human cell lines, and quantification of xenografted tumors in a high-throughput manner has been a challenge in the field. This method serves as a basis for ...

Xenografting of primary patient cancers or human cancer cell lines into model organisms is a widely used technique to study tumor progression and behavior in vivo, tumor response to drug treatment, and cancer cell interaction with the microenvironment, among others. Traditionally, cells are xenografted into immune-compromised mice, and this remains the standard in the field. However, this model system has several limitations, such as high cost, low replicate numbers, difficulties in accurately quantifying tumor burden in vivo, and the extended time that it takes for tumors to engraft and drug testing to be completed. In recent years, zebrafish have emerged as an alternate xenograft model, with the first being reported in 2005, with green fluorescent protein (GFP)-labeled human melanoma cell lines transplanted into blastula-stage embryos1,2. More recently, 2 day post-fertilization (dpf) zebrafish larvae have been used as xenograft recipients to allow for control of anatomic location of injection and for use in high resolution in vivo imaging of tumor interaction with the surrounding microenvironment3,4.
Zebrafish offer many advantages as a xenograft model. First, adult zebrafish can be housed and rapidly bred in large quantities at a relatively low cost. Each mating pair of adult zebrafish can produce hundreds of larval fish per week. Due to their small size, these larval zebrafish can be maintained in 96-well plates for high-throughput drug screening. Larvae do not have to be fed during the course of a typical xenograft experiment, as their yolk-sac provides the nutrients to sustain them for their first week of life. Furthermore, zebrafish do not have a fully functional immune system until 7 dpf, meaning that they do not require irradiation or immunosuppressive regimens prior to xenograft injection. Finally, optically clear zebrafish lines allow for high-resolution imaging of tumor-microenvironment interactions.
Perhaps the most promising application of zebrafish as a xenograft model is the ability to perform high-throughput drug screening on human cancer samples in a way that is not possible using any other model organism. Larvae absorb drugs from the water through the skin, enhancing the ease of drug administration5. Because animals are maintained in 96-well plates, typically in 100&#8722;300 &#956;L of water, screens require smaller drug quantities compared to mice. Currently, there are several different methods for standardization and quantification of the effect of drugs on human tumor burden in zebrafish, some of which are more practical than others for scaling-up single drug testing to high-throughput screening. For example, some groups dissociate fish into single cell suspensions, and quantify fluorescently labeled or stained tumor cells by imaging individual droplets of the suspension and quantifying fluorescence using a semi-automated ImageJ macro4. A semi-automated whole-larvae imaging method was developed in which larval fish were fixed in 96-well plates and imaged using an inverted fluorescent microscope before realignment of composite images and quantification of tumor cell foci6. Both of these assays are fairly labor-intensive methods for quantification, which has made truly high-throughput drug screening in zebrafish xenograft models impractical.
This issue has been addressed by the development of the Vertebrate Automated Screening Technology (VAST) Bioimager and Large Particle (LP) Sampler, a fluorescence microscope equipped imaging unit and automated sampler unit (Figure 1 and Table of Materials), which is a truly automated method for high-throughput imaging of zebrafish larvae7,8,9. With this unit, fish are anesthetized, sampled automatically from a 96-well plate, positioned in a capillary and rotated into the set orientation based on a preset user preference, imaged, and then either placed back into the same well of a new 96-well plate for further studies or discarded. Combining this imaging technology with zebrafish xenografts may allow for the possibility of personalized medicine that uses high-throughput drug screening of large drug compound libraries against individual patient tumors. Zebrafish xenografts also offer a large-scale and low-cost method for testing both toxicity and efficacy of novel compounds in vivo. Zebrafish can be used as a preliminary screening step before proceeding to mouse xenograft models.
We have developed a streamlined workflow for xenografting primary patient leukemia cells into zebrafish and performing high-throughput drug screens with automated imaging and quantification, which can be applied to any other primary patient tumor cells or cancer cell line. This workflow utilized a fluorescence microscope equipped imaging unit and automated sampler unit to improve upon current standardization and quantification methods and offers an automated alternative to previous, more labor-intensive methods of quantifying tumor mass in vivo.&#160;

<table border="0" cellpadding="0" cellspacing="0" style="width:901px;" width="901">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:288px;">10x TBE Liquid Concentrate</td>
			<td style="width:139px;">VWR</td>
			<td style="width:115px;">0658-5L</td>
			<td style="width:360px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">96-well plate, flat bottom</td>
			<td>CELLTREAT</td>
			<td>229195</td>
			<td style="width:360px;">VAST is compatible with a variety of standard or deep well 24, 48, or 96 well plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:288px;">Agarose</td>
			<td style="width:139px;">Fisher Scientific</td>
			<td style="width:115px;">BP160-500</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:288px;">Borosilicate Glass Capillary without Filament</td>
			<td style="width:139px;">Sutter Instrument Company</td>
			<td style="width:115px;">B100-50-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dexamethasone</td>
			<td>Enzo Life Sciences</td>
			<td>BML-EI126-0001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMSO</td>
			<td>Sigma-Aldrich</td>
			<td>D2438-5X10ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">E3 media</td>
			<td></td>
			<td>N/A</td>
			<td>5 mM NaCl, 0.17 mM KCl, 0.33 mM CaCl2, 0.33 mM MgSO4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:288px;">Femtotips Microloader Tips</td>
			<td style="width:139px;">Eppendorf</td>
			<td style="width:115px;">930001007</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fetal Bovine Serum (Premium Heat Inactivated)</td>
			<td>Atlanta Biologicals</td>
			<td>S11150H</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ImageJ</td>
			<td>FIJI</td>
			<td>N/A</td>
			<td>https://imagej.net/Fiji</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Iscove&#39;s Modified Dulbecco&#39;s Medium</td>
			<td>STEMCELL Technologies</td>
			<td>36150</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Large Particle (LP) Sampler</td>
			<td>Union Biometrica</td>
			<td>N/A</td>
			<td style="width:360px;">automated sampler unit http://www.unionbio.com/copas/features.aspx?id=8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Methotrexate</td>
			<td>Sigma-Aldrich</td>
			<td>A6770-10MG</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mineral Oil</td>
			<td>Fisher Scientific</td>
			<td>BP26291</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Phosphate Buffered Saline (1x)</td>
			<td>Caisson labs</td>
			<td>PBL06-6X500ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stage Micrometer (400-Stage)</td>
			<td>Hausser Scientific</td>
			<td>400-S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:288px;">Tricaine-S</td>
			<td style="width:139px;">Pentair Aquatic</td>
			<td style="width:115px;">TRS1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypan Blue</td>
			<td>Thermo Fisher</td>
			<td>T10282</td>
			<td></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;">VAST Bioimager</td>
			<td>Union Biometrica</td>
			<td>N/A</td>
			<td style="width:360px;">fluorescent equipped microscope imaging unit https://www.unionbio.com/vast/</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vincristine Sulfate</td>
			<td>Enzo Life Sciences</td>
			<td>BML-T117-0005</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Vybrant DiI Stain</td>
			<td>Thermo Fisher</td>
			<td>V22885</td>
			<td></td>
		</tr>
	</tbody>
</table>

drug screening of primary patient derived tumor xenografts in zebrafish

Patient derived xenograft models are critical in defining how different cancers respond to drug treatment in an in vivo system. Mouse models are the standard in the field, but zebrafish have emerged as an alternative model with several advantages, including the ability for high-throughput and low-cost drug screening. Zebrafish also allow for in vivo drug screening with large replicate numbers that were previously only obtainable with in vitro systems. The ability to rapidly perform large scale drug screens may open up the possibility for personalized medicine with rapid translation of results back to clinic. Zebrafish xenograft models could also be used to rapidly screen for actionable mutations based on tumor response to targeted therapies or to identify new anti-cancer compounds from large libraries. The current major limitation in the field has been quantifying and automating the process so that drug screens can be done on a larger scale and be less labor-intensive. We have developed a workflow for xenografting primary patient samples into zebrafish larvae and performing large scale drug screens using a fluorescence microscope equipped imaging unit and automated sampler unit. This method allows for standardization and quantification of engrafted tumor area and response to drug treatment across large numbers of zebrafish larvae. Overall, this method is advantageous over traditional cell culture drug screening as it allows for growth of tumor cells in an in vivo environment throughout drug treatment, and is more practical and cost-effective than mice for large scale in vivo drug screens.

Following the protocol described above, zebrafish were xenografted in the yolk and pericardium with primary patient PBMCs that were originally isolated from a T-cell acute lymphoblastic leukemia (T-ALL) patient at diagnosis and banked as a viable, frozen sample. At 48 hpi, xenografted fish were screened for fluorescently labeled tumor cells (Figure 2C,D) and treated with chemotherapy (dexamethasone or vincristine) or DMSO. Fish were imaged at 7 dpi, after 3 days on drug trea...

Watch this Scientific Journal Video about Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish at JoVE.com

Drug Screening of Primary Patient Derived Tumor Xenografts in Zebrafish

Zebrafish xenograft models allow for high-throughput drug screening and fluorescent imaging of human cancer cells in an in vivo microenvironment. We developed a workflow for large scale, automated drug screening on patient-derived leukemia samples in zebrafish using an automated fluorescence microscope equipped imaging unit.

Patient derived xenograft models are critical in defining how different cancers respond to drug treatment in an in vivo system. Mouse models are the ...

Our zebrafish xenograft drug screening workflow allows for automated imaging and quantification of human cancer cells and their response to drug treatment. It can be used to rapidly test the response of a patience's cancer cells to known drugs or to identify new anticancer compounds. Using zebrafish xenograph models and drug screening allows for Inviva replicant numbers that were previously only obtainable with in vitro systems.It is also much more cost effective than mouse models at screening through large libraries of compounds. This workflow has several steps from interjection of cancer cells in zebrafish to imaging of drug response that are learned best by visual demonstration. To begin, centrifuge a minimum of two times 10 to the sixth cells in five millimeters of PBS at 200 times g for five minutes, and aspirate the supernatant.Resuspend the cell palette in five millimeters of dii staining solution. Incubate the cells at 37 degrees Celsius protected from light for 20 minutes. Then vortex gently and incubate the cells on ice for 15 minutes protected from light.Then centrifuge the cells at 200 times g for five minutes and aspirate the supernatant. Wash the cells by adding five milliliters of PBS, centrifuging at 200 times g for five minutes, and aspirating the supernatant. Repeat the wash one additional time.Resuspend the cells in one microliter of PBS per 250 thousand live cells and transfer them to a 1.5 millimeter micro centrifuge tube. Keep the resuspended cells on ice in the dark. Prior to staining cells and injecting, make agarose plates for injecting by pouring 25 millileiers of three percent agarose in 1X TBE into a petri dish and allow it to solidify.Store the plates at four degrees Celsius for up to two weeks. Also prior to staining cells and injecting, dechlorinate two day post fertilization zebra fish using forceps under a dissecting microscope. Pull from the opposite ends of the protective chorion of the zebra fish with forceps until the chorion tears and the zebra fish becomes unenveloped.To prevent clumping of cells during microinjection, pre chill non filamentous borosilicate glass needles at four degrees Celsius or on ice. Immediately after staining cells, use a microloader pipette tip to load five microliters of stained cells into the chilled needle. Load the needle into the microinjector arm.Level the needle tip using a sterile razor blade. Using a stage micrometer, measure the droplet size in mineral oil. Keep the droplet volume consistently at two nanoliters, which is around 1.5 millimeters in diameter.One minute after anesthesia, transfer the anesthetized larvae to a prepared flat surface injection plate with three percent agarose, and inject the larvae with one pump of stained cells at the desired injection site. All injections should be completed within one to three hours after staining the cells to prevent clumping of the needle. Wash the larvae off the injection plate into a 10 centimeter petri dish containing E3 media without methylene blue and incubate at 28 degrees Celsius for a one hour recovery period.Move the dish of the injected larvae into a 34 degree Celsius incubator. With an empty petri dish placed between the shelf and the petri dish of larvae to act as a buffer. At 48 hour post injection, screen zebra fish larvae for fluorescent tumor cell engraftment and health.Remove any dead or malformed zebra fish, and select zebra fish with similar engraftment. Remove unengrafted zebra fish. For yolk injected fish, remove fish where borders of the yoke cannot be seen around the engrafted cell mass.For pericardium injected fish, remove fish where injected cell mass encroaches into the yolk sack. To transfer the selected fish to a 96-well plate, first cut the tip off a 200 microliter pipette tip, just large enough for a four day post fertilization zebra fish to fit through. Aspirate 150 microliters of E3 media with one zebra fish from the plate using the P200 pipette and add it to an empty well of a flat bottom 96-well plate.Add 150 microliters of 2X diluted drug solution to each well containing zebra fish larvae to reach a final volume of 300 microliters with 1X drug solution per well. Incubate the plate at 34 degrees Celsius. Check for dead zebra fish daily.After two days, if desired, refresh the drug by replacing 200 microliters of liquid from each well with 1X drug solution or DMSO in E3 media. In the Zen blue software, remove all unwanted fluorescent channels in the imaging software and add the Dii channel. Check the desired fluorescent channel.In the same window, select how the images will be taken, Z stacks, automation, loops and series, et cetera. Image the DMSO control fish before the drug treated fish. And set the appropriate exposure time in the imaging software.To quantify the fluorescence, open imagej software. Go to file, open, and select the desired CZI file. The software brings up an import options window.For stack viewing, select hyperstacks, check open files individually, check auto scale, and check split channels. For the color option, select colorized. Then click plugins, macros, record.Click image, adjust, threshold. Select image type as red in the drop down menu on the right side of the threshold window. Adjust the minimum threshold until the software is only highlighting areas with fluorescence, and then click apply.The software converts the photo to black and white with the selected area in black. Click analyze and measure. The software pulls up a results window containing the fluorescent area for that image.Click create on the macro recorder window. This opens up a new window with the code for the macro. Highlight all of the desired images for analysis and open according to stacking viewing or color option.Select run on the window with the macro. The results window now contains the area for each image. In this protocol, at 48 hour post injection, xenografted fish were screened for fluorescently labeled tumor cells and treated with chemotherapy or DMSO.Overall, xenografted fish treated with Vincristine showed the largest and most consistent decrease in xenografted cell mass compared to DMSO treated fish. Dexamethasone treated fish showed about half the reduction in tumor area compared to Vincristine. But still showed a reduction in tumor area compared to DMSO.This procedure can be used to screen any cancer cell line or patient sample for response to different drugs or specific targeted therapies giving insight into each patient's tumor.

drug-screening-primary-patient-derived-tumor-xenografts

Research

JoVE Journal

Cancer Research

Labeling of Breast Cancer Patient-derived Xenografts with Traceable Reporters for Tumor Growth and Metastasis Studies

The use of preclinical models to study tumor biology and response to treatment is central to cancer research. Long-established human cell lines, and many transgenic mouse models, often fail to recapitulate the key aspects of human malignancies. Thus, alternative models that better represent the heterogeneity of patients' tumors and their metastases are being developed. Patient-derived xenograft (PDX) models in which surgically resected tumor samples are engrafted into immunocompromised mice have become an attractive alternative as they can be transplanted through multiple generations,and more efficiently reflect tumor heterogeneity than xenografts derived from human cancer cell lines. A limitation to the use of PDXs is that they are difficult to transfect or transduce to introduce traceable reporters or to manipulate gene expression. The current protocol describes methods to transduce dissociated tumor cells from PDXs with high transduction efficiency, and the use of labeled PDXs for experimental models of breast cancer metastases. The protocol also demonstrates the use of labeled PDXs in experimental metastasis models to study the organ-colonization process of the metastatic cascade. Metastases to different organs can be easily visualized and quantified using bioluminescent imaging in live animals, or GFP expression during dissection and in excised organs. These methods provide a powerful tool to extend the use of multiple types of PDXs to metastasis research.

We describe a method for stable labeling of patient-derived xenografts (PDXs) with lentiviral particles expressing green-fluorescent protein and luciferase reporters. This method allows for tracking the growth of PDXs at the primary site, as well as detecting spontaneous and experimental metastases using in vivo imaging systems.

The use of preclinical models to study tumor biology and response to treatment is central to cancer research. Long-established human cell lines, and many ...

Establishment of a Primary Culture of Patient-derived Soft Tissue Sarcoma

Soft tissue sarcomas (STS) represent a spectrum of heterogeneous malignancies with a difficult diagnosis, classification, and management. To date, more than 50 histological subtypes of these rare solid tumors have been identified. Thus, due to their extraordinary diversity and low incidence, our understanding of the biology of these tumors is still limited. Patient-derived cultures represent the ideal platform to study STS pathophysiology and pharmacology. We thus developed a human preclinical model of STS starting from tumor specimens harvested from patients undergoing surgical resection. Patient-derived STS cell cultures were obtained from the surgical specimens by collagenase digestion and isolated by filtration. Cells were counted, seeded, and left for 14 days in standard monolayer cultures and then processed by downstream analysis. Before performing molecular or pharmaceutical analyses, the establishment of STS primary cultures was confirmed through the evaluation of cytomorphologic features and, when available, immunohistochemical markers. This method represents a useful tool 1) to study the natural history of these poorly explored malignancies and 2) to test the effects of different drugs in an effort to learn more about their mechanisms of action.

The following protocol focuses on the establishment of a primary culture of patient-derived soft tissue sarcoma (STS). This model could help us to better understand the molecular background and pharmacological profile of these rare malignancies and could represent a starting point for further research aimed at improving STS management.

Soft tissue sarcomas (STS) represent a spectrum of heterogeneous malignancies with a difficult diagnosis, classification, and management. To date, more ...

Flow Cytometry to Estimate Leukemia Stem Cells in Primary Acute Myeloid Leukemia and in Patient-derived-xenografts, at Diagnosis and Follow Up

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in adults. Initially, AML is a disease of hematopoietic stem cells (HSC) characterized by arrest of differentiation, subsequent accumulation of leukemia blast cells, and reduced production of functional hematopoietic elements. Heterogeneity extends to the presence of leukemia stem cells (LSC), with this dynamic cell compartment evolving to overcome various selection pressures imposed upon during leukemia progression and treatment. To further define the LSC population, the addition of CD90 and CD45RA allows the discrimination of normal HSCs and multipotent progenitors within the CD34+CD38- cell compartment. Here, we outline a protocol to detect simultaneous expression of several putative LSC markers (CD34, CD38, CD45RA, CD90) on primary blast cells of human AML by multiparametric flow cytometry. Furthermore, we show how to quantify three progenitor populations and a putative LSC population with increasing degree of maturation. We confirmed the presence of these populations in corresponding patient-derived-xenografts. This method of detection and quantification of putative LSC may be used for clinical follow-up of chemotherapy response (i.e., minimal residual disease), as residual LSC may cause AML relapse.

We outline a protocol to detect simultaneous expression of leukemia stem cell markers on primary acute myeloid leukemia cells by flow cytometry. We show how to quantify three progenitor populations and a putative LSC population with increasing degree of maturation. We confirmed the presence of these populations in corresponding patient-derived-xenografts.

Acute myeloid leukemia (AML) is a heterogeneous, and if not treated, fatal disease. It is the most common cause of leukemia-associated mortality in ...

Isolation and Characterization of Tumor-initiating Cells from Sarcoma Patient-derived Xenografts

The existence and importance of tumor-initiating cells (TICs) have been supported by increasing evidence during the past decade. These TICs have been shown to be responsible for tumor initiation, metastasis, and drug resistance. Therefore, it is important to develop specific TIC-targeting therapy in addition to current chemotherapy strategies, which mostly focus on the bulk of non-TICs. In order to further understand the mechanism behind the malignancy of TICs, we describe a method to isolate and to characterize TICs in human sarcomas. Herein, we show a detailed protocol to generate patient-derived xenografts (PDXs) of human sarcomas and to isolate TICs by fluorescence-activated cell sorting (FACS) using human leukocyte antigen class I (HLA-1) as a negative marker. Also, we describe how to functionally characterize these TICs, including a sphere formation assay and a tumor formation assay, and to induce differentiation along mesenchymal pathways. The isolation and characterization of PDX TICs provide clues for the discovery of potential targeting therapy reagents. Moreover, increasing evidence suggests that this protocol may be further extended to isolate and characterize TICs from other types of human cancers.

We describe a detailed protocol for the isolation of tumor-initiating cells from human sarcoma patient-derived xenografts by fluorescence-activated cell sorting, using human leukocyte antigen-1 (HLA-1) as a negative marker, and for the further validation and characterization of these HLA-1-negative tumor-initiating cells.

The existence and importance of tumor-initiating cells (TICs) have been supported by increasing evidence during the past decade. These TICs have been ...

Patient-derived Heterogeneous Xenograft Model of Pancreatic Cancer Using Zebrafish Larvae as Hosts for Comparative Drug Assessment

Patient-derived tumor xenograft (PDX) and cell-derived tumor xenograft (CDX) are important techniques for preclinical assessment, medication guidance and basic cancer researches. Generations of PDX models in traditional host mice are time-consuming and only working for a small proportion of samples. Recently, zebrafish PDX (zPDX) has emerged as a unique host system, with the characteristics of small-scale and high efficiency. Here, we describe an optimized methodology for generating a dual fluorescence-labeled tumor xenograft model for comparative chemotherapy assessment in zPDX models. Tumor cells and fibroblasts were enriched from freshly-harvested or frozen pancreatic cancer tissue at different culture conditions. Both cell groups were labeled by lentivirus expressing green or red fluorescent proteins, as well as an anti-apoptosis gene BCL2L1. The transfected cells were pre-mixed and co-injected into the 2 dpf larval zebrafish that were then bred in modified E3 medium at 32 &#176;C. The xenograft models were treated by chemotherapy drugs and/or BCL2L1 inhibitor, and the viabilities of both tumor cells and fibroblasts were investigated simultaneously. In summary, this protocol allows researchers to quickly generate a large amount of zPDX models with a heterogeneous tumor microenvironment and provides a longer observation window and a more precise quantitation in assessing the efficiency of drug candidates.

This protocol describes optimization procedures in a virus-based dual fluorescence-labeled tumor xenograft model using larval zebrafish as hosts. This heterogeneous xenograft model mimics the tissue composition of pancreatic cancer microenvironment in vivo and serves as a more precise tool for assessing drug responses in personalized zPDX (zebrafish patient-derived xenograft) models.

Patient-derived tumor xenograft (PDX) and cell-derived tumor xenograft (CDX) are important techniques for preclinical assessment, medication guidance and ...

Physiologic Patient Derived 3D Spheroids for Anti-neoplastic Drug Screening to Target Cancer Stem Cells

In this protocol, we outline the procedure for generation of tumor spheroids within 384-well hanging droplets to allow for high-throughput screening of anti-cancer therapeutics in a physiologically representative microenvironment. We outline the formation of patient derived cancer stem cell spheroids, as well as, the manipulation of these spheroids for thorough analysis following drug treatment. Specifically, we describe collection of spheroid morphology, proliferation, viability, drug toxicity, cell phenotype and cell localization data. This protocol focuses heavily on analysis techniques that are easily implemented using the 384-well hanging drop platform, making it ideal for high throughput drug screening. While we emphasize the importance of this model in ovarian cancer studies and cancer stem cell research, the 384-well platform is amenable to research of other cancer types and disease models, extending the utility of the platform to many fields. By improving the speed of personalized drug screening and the quality of screening results through easily implemented physiologically representative 3D cultures, this platform is predicted to aid in the development of new therapeutics and patient-specific treatment strategies, and thus have wide-reaching clinical impact.

This protocol describes generation of patient-derived spheroids, and downstream analysis including quantification of proliferation, cytotoxicity testing, flow cytometry, immunofluorescence staining and confocal imaging, in order to assess drug candidates&#8217; potential as anti-neoplastic therapeutics. This protocol supports precision medicine with identification of specific drugs for each patient and stage of disease.

In this protocol, we outline the procedure for generation of tumor spheroids within 384-well hanging droplets to allow for high-throughput screening of ...

In Vivo Imaging and Quantitation of the Host Angiogenic Response in Zebrafish Tumor Xenografts

Tumor angiogenesis is a key target of anti-cancer therapy and this method has been developed to provide a new model to study this process in vivo. A zebrafish xenograft is created by implanting mammalian tumor cells into the perivitelline space of two days-post-fertilization zebrafish embryos, followed by measuring the extent of the angiogenic response observed at an experimental endpoint up to two days post-implantation. The key advantage to this method is the ability to accurately quantitate the zebrafish host angiogenic response to the graft. This enables detailed examination of the molecular mechanisms as well as the host vs tumor contribution to the angiogenic response. The xenografted embryos can be subjected to a variety of treatments, such as incubation with potential anti-angiogenesis drugs, in order to investigate strategies to inhibit tumor angiogenesis. The angiogenic response can also be live-imaged in order to examine more dynamic cellular processes. The relatively undemanding experimental technique, cheap maintenance costs of zebrafish and short experimental timeline make this model especially useful for the development of strategies to manipulate tumor angiogenesis.

The aim of this method is to generate an in vivo model of tumor angiogenesis by xenografting mammalian tumor cells into a zebrafish embryo that has fluorescently-labelled blood vessels. By imaging the xenograft and associated vessels, a quantitative measurement of the angiogenic response can be obtained.

Tumor angiogenesis is a key target of anti-cancer therapy and this method has been developed to provide a new model to study this process in vivo. A ...

Establishment of Gastric Cancer Patient-derived Xenograft Models and Primary Cell Lines

The use of preclinical models to advance our understanding of tumor biology and investigate the efficacy of therapeutic agents is key to cancer research. Although there are many established gastric cancer cell lines and many conventional transgenic mouse models for preclinical research, the disadvantages of these in vitro and in vivo models limit their applications. Because the characteristics of these models have changed in culture, they no longer model tumor heterogeneity, and their responses have not been able to predict responses in humans. Thus, alternative models that better represent tumor heterogeneity are being developed. Patient-derived xenograft (PDX) models preserve the histologic appearance of cancer cells, retain intratumoral heterogeneity, and better reflect the relevant human components of the tumor microenvironment. However, it usually takes 4-8 months to develop a PDX model, which is longer than the expected survival of many gastric patients. For this reason, establishing primary cancer cell lines may be an effective complementary method for drug response studies. The current protocol describes methods to establish PDX models and primary cancer cell lines from surgical gastric cancer samples. These methods provide a useful tool for drug development and cancer biology research.

The current protocol describes methods to establish patient-derived xenograft (PDX) models and primary cancer cell lines from surgical gastric cancer samples. The methods provide a useful tool for drug development and cancer biology research.

The use of preclinical models to advance our understanding of tumor biology and investigate the efficacy of therapeutic agents is key to cancer research. ...

Testing Targeted Therapies in Cancer using Structural DNA Alteration Analysis and Patient-Derived Xenografts

We present here an integrative approach for testing efficacy of targeted therapies that combines the next generation sequencing technolo-gies, therapeutic target analyses and drug response monitoring using patient derived xenografts (PDX). This strategy was validated using ovarian tumors as an example. The mate-pair next generation sequencing (MPseq) protocol was used to identify structural alterations and followed by analysis of potentially targetable alterations. Human tumors grown in immunocompromised mice were treated with drugs selected based on the genomic analyses. Results demonstrated a good correlation between the predicted and the observed responses in the PDX model. The presented approach can be used to test the efficacy of combination treatments and aid personalized treatment for patients with recurrent cancer, specifically in cases when standard therapy fails and there is a need to use drugs off label.

Here we present a protocol to test the efficacy of targeted therapies selected based on the genomic makeup of a tumor. The protocol describes identification and validation of structural DNA rearrangements, engraftment of patients&#8217; tumors into mice and testing responses to corresponding drugs.

We present here an integrative approach for testing efficacy of targeted therapies that combines the next generation sequencing technolo-gies, therapeutic ...

Enhanced Viability for Ex vivo 3D Hydrogel Cultures of Patient-Derived Xenografts in a Perfused Microfluidic Platform

Patient-derived xenografts (PDX), generated when resected patient tumor tissue is engrafted directly into immunocompromised mice, remain biologically stable, thereby preserving molecular, genetic, and histological features, as well as heterogeneity of the original tumor. However, using these models to perform a multitude of experiments, including drug screening, is prohibitive both in terms of cost and time. Three-dimensional (3D) culture systems are widely viewed as platforms in which cancer cells retain their biological integrity through biochemical interactions, morphology, and architecture. Our team has extensive experience culturing PDX cells in vitro using 3D matrices composed of hyaluronic acid (HA). In order to separate mouse fibroblast stromal cells associated with PDXs, we use rotation culture, where stromal cells adhere to the surface of tissue culture-treated plates while dissociated PDX tumor cells float and self-associate into multicellular clusters. Also floating in the supernatant are single, often dead cells, which present a challenge in collecting viable PDX clusters for downstream encapsulation into hydrogels for 3D cell culture. In order to separate these single cells from live cell clusters, we have employed density step gradient centrifugation. The protocol described here allows for the depletion of non-viable single cells from the healthy population of cell clusters that will be used for further in vitro experimentation. In our studies, we incorporate the 3D cultures in microfluidic plates which allow for media perfusion during culture. After assessing the resultant cultures using a fluorescent image-based viability assay of purified versus non-purified cells, our results show that this additional separation step substantially reduced the number of non-viable cells from our cultures.

This protocol demonstrates methods to enable extended in vitro culture of patient-derived xenografts (PDX). One step enhances overall viability of multicellular cluster cultures in 3D hydrogels, through straightforward removal of non-viable single cells. A secondary step demonstrates best practices for PDX culture in a perfused microfluidic platform.

Patient-derived xenografts (PDX), generated when resected patient tumor tissue is engrafted directly into immunocompromised mice, remain biologically ...