Name: testing targeted therapies in cancer using structural dna alteration analysis and patient-derived xenografts
Uploaded: 2020-07-25T14:00:00
Description: Watch this Scientific Journal Video about Testing Targeted Therapies in Cancer using Structural DNA Alteration Analysis and Patient-Derived Xenografts at JoVE.com

We thank the members of the Mayo Clinic Center for Individualized Medicine (CIM) Dr. Lin Yang and Faye R. Harris, MS, for the help in conducting experiments. This work was supported by Mr. and Mrs. Neil E. Eckles&#8217; Gift to the Mayo Clinic Center for Individualized Medicine (CIM).

Fresh tissues from consenting patients with ovarian cancer were collected at the time of debulking surgery according to a protocol approved by Mayo Clinic Institutional Review Board (IRB). All animal procedures and treatments used in this protocol were approved by Mayo Clinic Institutional Animal Care and Use Committee (IACUC) and followed animal care guidelines.
1. Mate pair sequencing and analyses
NOTE: Either fresh or flash frozen tissue must be used for mate pair ...

We describe the approach and protocols we used to conduct a &#8220;clinical trial&#8221; in PDX models that takes advantage of molecular characteristics of the tumor as obtained by genomic profiling to determine the best choice of drugs for testing. Multiple sequencing platforms are currently used for genomic characterization of primary tumors including whole genome sequencing, RNAseq and customized gene panels. For high grade serous ovarian carcinoma, MPseq to identify structural alterations, DNA rearrangements and copy...

Patient-derived xenografts (PDXs), which are generated from the implantation of patient tumor pieces into immunodeficient mice, have emerged as a powerful preclinical model to aid personalized anti-cancer care. PDX models have been successfully developed for a variety of human malignancies. These include breast and ovarian cancers, malignant melanoma, colorectal cancer, pancreatic adenocarcinoma, and non-small cell lung cancer1,2,3,4,5. Tumor tissue can be implanted orthotopically or heterotopically. The former, considered more accurate but technically difficult, involves transplantation directly into the organ of tumor origin. These types of models are believed to precisely mimic histology of the original tumor due to the &#8220;natural&#8217; microenvironment for the tumor6,7. For example, orthotopic transplantation into the bursa of the mouse ovary resulted in tumor dissemination into the peritoneal cavity and the production of ascites, typical of ovarian cancer8. Similarly, injection of breast tumors into the thoracic instead of the abdominal mammary gland affected the PDX success rate and behavior9. However, orthotopic models require sophisticated imaging systems to monitor tumor growth. Heterotopic implantation of solid tumor is typically performed by implanting tissue into the subcutaneous flank of a mouse which allows for easier monitoring of tumor growth and is less expensive and time consuming7. However, tumors grown subcutaneously rarely metastasize unlike as observed in the case of orthotopic implantation10.
The success rate of engraftment has been shown to vary and greatly depend on the tumor type. More aggressive tumors and tissue specimens containing a higher percent of tumor cells were reported to have better success rates12,13. Consistent with this, tumors derived from metastatic sites were shown to engraft at frequencies of 50&#8211;80%, while those from primary sites engraft at frequencies as low as 14%12. In contrast, tissue containing necrotic cells and fewer viable tumor cells engraft poorly. Tumor growth can also be promoted by the addition of basement membrane matrix proteins into the tissue mix at the time of the injection into mice14 without compromising properties of the original tumor. The size and number of tissue pieces intended for implantation were also found to affect the success rate of engraftment. Greater tumor take-rates were reported for implantation in the sub-renal capsule compared to subcutaneous implantation due to the ability of the sub-renal capsule to maintain the original tumor stroma and provide the host stromal cells as well15.
Most studies use NOD/SCID immunodeficient mice, which lack natural killer cells16 and have been shown to increase the tumor engraftment, growth and metastasis compared to other strains14. However, additional monitoring is required as they may develop thymic lymphomas as early as 3-4 month of age13. In ovarian tumor transplants grown in SCID mice, the outgrowth of B cells was successfully inhibited by rituximab, preventing the development of lymphomas but without impacting the engraftment of ovarian tumors17.
More recently, NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice, carrying a null mutation in the gene encoding the interleukin 2 receptor gamma chain18, became a frequently used strain for the generation of PDX models. Tumors from established PDX models passaged to future generations of mice are reported to retain histological and molecular properties for 3 to 6 generations19,20. Numerous studies have shown that the treatment outcomes in PDX models mimic those of their corresponding patients2,3,4,21,22,23. The response rate to chemotherapy in PDX models for non-small lung cancer and colorectal carcinomas was similar to that in clinical trials for the same drugs24,25. Studies conducted in PDX models, developed for patients enrolled in clinical trials, demonstrated responses to tested drugs similar to those observed clinically in corresponding patients2,3,4.
High&#8211;throughput genomic analyses of a patient tumor in conjunction with PDX models provide a powerful tool to study correlations between specific genomic alterations and a therapeutic response. These have been described in a few publications26,27. For example, therapeutic responses to the EGFR inhibitor cetuximab in a set of colorectal PDX models carrying EGFR amplification, paralleled clinical responses to cetuximab in patients28.
There are a few challenges associated with the development and application of PDX models. Among those is tumor heterogeneity29,30 that may compromise the accuracy of treatment response interpretation as a single cell clone with higher proliferative capacity within a PDX can outgrow the other ones31, thus resulting in a loss of heterogeneity. Additionally, when single tumor biopsies are used to develop PDX, some of the cell populations may be missed and will not be represented in the final graft. Multiple samples from the same tumor are recommended for implantation to resolve this issue. Although PDX tumors tend to contain all the cell types of the original donor tumor, these cells are gradually substituted by those of murine origin3. The interplay between murine stroma and human tumor cells in PDX models is not well understood. Nevertheless, stromal cells were shown to recapitulate tumor microenvironment33.
Despite these limitations, PDX models remain among the most valuable tools for translational research as well as personalized medicine for selecting patient therapies. Major applications of PDXs include biomarker discovery and drug testing. PDX models are also successfully used to study drug resistance mechanisms and identify strategies to overcome drug resistance34,35. The approach described in the present manuscript allows the researcher to identify potential therapeutic targets in human tumors and to assess the efficacy of corresponding drugs in vivo, in mice harboring engrafted tumors which were initially genomically characterized. The protocol uses ovarian tumors engrafted intraperitoneally but is applicable to any type of tumor sufficiently aggressive to grow in mice2,3,12.

<table>
	<tbody>
		<tr>
			<td>3M Vetbond</td>
			<td>3M, Co.</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-AKT antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>9272</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-GAPDH antibody(G-9)</td>
			<td>Santa Cruz Biotech. Inc.</td>
			<td>sc-365062</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-MAPK antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>9926</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-phospho-AKT antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>9271</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-mTOR antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>2972</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Phospho-mTOR antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>2971</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Phospho-S6 antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>4858</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Rictor antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>2114</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-S6 antibody</td>
			<td>Cell Signaling Technologies, Inc.</td>
			<td>2217</td>
			<td></td>
		</tr>
		<tr>
			<td>Captisol</td>
			<td>ChemScene, Inc.</td>
			<td>cs-0731</td>
			<td></td>
		</tr>
		<tr>
			<td>Carboplatin</td>
			<td>NOVAPLUS, Inc.</td>
			<td>61703-360-18</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Mediatech, Inc.</td>
			<td>10-013-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Easy-A Hi-Fi PCR Cloning Enzyme</td>
			<td>Agilent, Inc.</td>
			<td>600404-51</td>
			<td></td>
		</tr>
		<tr>
			<td>Lubricant</td>
			<td>Cardinal Healthcare</td>
			<td>82-280</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>Corning, Inc.</td>
			<td>356234</td>
			<td></td>
		</tr>
		<tr>
			<td>McCoy&#39;s media</td>
			<td>Mediatech, Inc.</td>
			<td>10-050-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>MK-2206</td>
			<td>ApexBio, Inc.</td>
			<td>A3010</td>
			<td></td>
		</tr>
		<tr>
			<td>MK-8669</td>
			<td>ARIAD Pharmaceuticals, Inc.</td>
			<td>AP23573</td>
			<td></td>
		</tr>
		<tr>
			<td>Nair Sensitive Skin</td>
			<td>Church &#38; Dwight Co.</td>
			<td>Nair Hair Remover Shower Power Sensitive</td>
			<td></td>
		</tr>
		<tr>
			<td>NOD/SCID mice</td>
			<td>Charles River, Inc.</td>
			<td>NOD.CB17-Prkdcscid/NCrCrl</td>
			<td></td>
		</tr>
		<tr>
			<td>Paclitaxel</td>
			<td>NOVAPLUS, Inc.</td>
			<td>55390-304-05</td>
			<td></td>
		</tr>
		<tr>
			<td>PEG400</td>
			<td>Millipore Sigma, Inc.</td>
			<td>88440-250ML-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Perjeta</td>
			<td>Genetech, Co.</td>
			<td>Pertuzumab</td>
			<td></td>
		</tr>
		<tr>
			<td>Rituximab</td>
			<td>Genetech, Co.</td>
			<td>Rituxan</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI1640</td>
			<td>Mediatech, Inc.</td>
			<td>10-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>SCID mice</td>
			<td>Harlan Laboratories, Inc.</td>
			<td>C.B.-17/IcrHsd-PrkdcscidLystbg</td>
			<td></td>
		</tr>
		<tr>
			<td>SLAx 13-6MHz linear transducer</td>
			<td>FUJIFILM SonoSite, Inc</td>
			<td>HFL38xp</td>
			<td></td>
		</tr>
		<tr>
			<td>SonoSite S-series Ultrasound machine</td>
			<td>FUJIFILM SonoSite, Inc</td>
			<td>SonoSite SII</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 80</td>
			<td>Millipore Sigma, Inc.</td>
			<td>P4780-100ML</td>
			<td></td>
		</tr>
	</tbody>
</table>

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.

Tissue from resected ovarian tumors at the time of debulking surgeries were collected in accordance with IRB guidance and used for 1) genomic characterization and 2) engraftment in immunocompromised mice (Figure 1). Mate-pair sequencing protocol36,37 was used to identify structural alterations in DNA including losses, gains and amplifications. A representative genome plot illustrating a landscape of genomic changes in one tumor (desi...

Watch this Scientific Journal Video about Testing Targeted Therapies in Cancer using Structural DNA Alteration Analysis and Patient-Derived Xenografts at JoVE.com

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

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 ...

The protocol described here is aimed to demonstrate an algorithm for testing treatment efficacy using in vivo cancer models. The protocol consists of a combination of several techniques. Whole genome bio-sequencing of human tumor specimens is used to identify genomic alterations.These include both gene rearrangements and gene copy number changes. So the analysis of identified alterations is performed in order to select potentially druggable changes. The drugs selected based on genomic analysis are then used for in vivo treatment of corresponding tumors grown in immunocompromised mice.The developed algorithm represents a promising approach to aid treatment decisions for the care of cancer patients. Use the Panda tool or an analogous software to identify targetable alterations. We can list the genes which were identified by microsequencing resulted as a simple tab delineated file using standard accepted gene symbols.Add the pound sign to the headerline of the list to ensure that the table header is transferred to the pathway level U of the software. Upload the file by clicking on the corresponding navigation tab. Assign a single icon to represent the underlying data by clicking on the icon of choice, and then clicking on the finalize tab.Once then a patient files are uploaded, preview the page to identify a column that displays the number of annotated genes per pathway. This is the last column on the right. Use a pathway filter in the upper left of the main window to restrict the number of pathways displayed to the ones that contain the genes of interest.To identify pathways that have more genes annotated than would be expected by chance, use a function located under the enrichment tab. A column then is added to the main table that shows corresponding p-value from a Fisher's exact test. Select the database to display potential druggable genes from preset annotation by checking an appropriate icon on the left of the main window.To select a pathway for visualization, click on its name displayed in the pathway viewer page. Icons representing each annotation set are displayed next to the associated gene. Clicking on any gene in the pathway will open the corresponding gene cards page.Select the pathways that showed annotated genes of interest and hits for potential drugs for further analysis. Perform the tissue work in a laminar flow hood to maintain sterile conditions. Lay the tumor tissue in a dish containing cold PBS or tissue culture media, such as RPMI, DMEM, containing antibiotics.Identify and isolate viable tumor material from adjacent normal and necrotic tissue with the help from a pathologist. Use sterile forceps and scalpel to remove necrotic material pointed out by a pathologist. To perform subcutaneous engraftment, cut the tumor tissue with sterile forceps, scalpel or surgical scissors into small fragments, roughly 2 x 2 x 2 millimeters in size.Transfer the fragmented tissue to a pre-chilled petri dish on ice. Let cold matrigel into the dish with the fragmented tissue, approximately 200 microliters per 10 pieces of tissue. Mix well and let the tissue fragments soak in the matrigel for 10 minutes.Use sterile surgical scissors and forceps to make a 5-10 millimeters vertical skin incision on both flanks of a mouse. Insert straight forceps gently into the subcutaneous space to create a pocket large enough for a tumor fragment to be placed under the fat pad. Use sterile straight forceps to insert tumor fragments in the previously prepared pocket in each of five mice.Close the skin incision using tissue glue. After implantation, to inhibit lymphocyte proliferation, inject each mouse with 100 microliters of rituximab. Prepare the mouse for oral gavage by pinching the skin of the back and bending it backward so that the head and lips of the mouse are immobilized.Insert the gavage probe down the back of the throat of the mouse until the probe reaches the esophagus. Make sure that the probe is not inserted too far as the lungs of the mouse may perforate causing death. The representative genome float illustrates the landscape of genomic changes in one tumor.Typical for high-grade serosubtype tumors, multiple gains blue lines and losses red lines, were identified indicating high levels of genomic instability. The top trend alteration for therapeutic intervention in the OC101 tumor was an amplification at chromosome 17, involving ERBB2, a gene which codes for HER2 receptor. To validate the results on the DNA level, several sets of specific primers were designed for the edges of the amplified region.And PCR was carried out. No amplification product was absorbed when control human DNA was used. Specific bands were identified for OC101 tumor DNA.In another variant tumor, T14, numerous DNA gains were observed. Those included AKT2 in RICTOR genes. Validation carried out on the protein level, using immunoblotting showed high levels of AKT in RICTOR.A significant reduction in the tumor burden was observed in the chemotherapy treated group by the end of week six. There was an extra benefit over chemotherapy alone in the groups which received a combination treatment. Tumor tissue was collected for molecular analysis of treatment response at the end of the treatment trial.Total and phosphorylated levels of S6, AKT, and mTOR were determined using immunoblotting. Comparison of the levels of these proteins in untreated, chemotherapy-treated, and treated with AKT or mTOR inhibitor showed a marked decrease for the latter two. The presented approach is very useful to conduct the clinical trial in PDX models.It takes advantage of molecular characteristics of the tumor as obtained by genomic profiling to determine the best choice of drugs for testing.

testing-targeted-therapies-cancer-using-structural-dna-alteration

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Unit 2

Cancer

SCIENTISTS IN ACTION

Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies

Patient derived tumor xenograft (PDTX) models provide a necessary platform in facilitating anti-cancer drug development prior to human trials. Human tumor pieces are injected subcutaneously into athymic nude mice (immunocompromised, T cell deficient) to create a bank of tumors and subsequently are passaged into different generations of mice in order to maintain these tumors from patients. Importantly, cellular heterogeneity of the original tumor is closely emulated in this model, which provides a more clinically relevant model for evaluation of drug efficacy studies (single agent and combination), biomarker analysis, resistant pathways and cancer stem cell biology. Some limitations of the PDTX model include the replacement of the human stroma with mouse stroma after the first generation in mice, inability to investigate treatment effects on metastasis due to the subcutaneous injections of the tumors, and the lack of evaluation of immunotherapies due to the use of immunocompromised mice. However, even with these limitations, the PDTX model provides a powerful preclinical platform in the drug discovery process.

Utilizing patient-derived tumors in a subcutaneous preclinical model is an excellent way to study the efficacy of novel therapies, predictive biomarker discovery, and drug resistant pathways. This model, in the drug development process, is essential in determining the fate of many novel anti-cancer therapies prior to clinical investigation.

Patient derived tumor xenograft (PDTX) models provide a necessary platform in facilitating anti-cancer drug development prior to human trials. Human tumor ...

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 ...

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. ...

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 ...

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.

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 ...

High-Throughput In Vitro Assay using Patient-Derived Tumor Organoids

Patient-derived tumor organoids (PDOs) are expected to be a preclinical cancer model with better reproducibility of disease than traditional cell culture models. PDOs have been successfully generated from a variety of human tumors to recapitulate the architecture and function of tumor tissue accurately and efficiently. However, PDOs are unsuitable for an in vitro high-throughput assay system (HTS) or cell analysis using 96-well or 384-well plates when evaluating anticancer drugs because they are heterogeneous in size and form large clusters in culture. These cultures and assays use extracellular matrices, such as Matrigel, to create tumor tissue scaffolds. Therefore, PDOs have a low throughput and high cost, and it has been difficult to develop a suitable assay system. To address this issue, a simpler and more accurate HTS was established using PDOs to evaluate the potency of anticancer drugs and immunotherapy. An in vitro HTS was created that uses PDOs established from solid tumors cultured in 384-well plates. An HTS was also developed for assessment of antibody-dependent cellular cytotoxicity activity to represent the immune response using PDOs cultured in 96-well plates.

High-Throughput In Vitro Assay using Patient-Derived Tumor Organoids

A highly accurate in vitro high-throughput assay system was developed to evaluate anticancer drugs using patient-derived tumor organoids (PDOs), similar to cancer tissues but are unsuitable for in vitro high-throughput assay systems with 96-well and 384-well plates.

Patient-derived tumor organoids (PDOs) are expected to be a preclinical cancer model with better reproducibility of disease than traditional cell culture ...

Profiling Sensitivity to Targeted Therapies in EGFR-Mutant NSCLC Patient-Derived Organoids

Novel 3D cancer organoid cultures derived from clinical patient specimens represent an important model system to evaluate intratumor heterogeneity and treatment response to targeted inhibitors in cancer. Pioneering work in gastrointestinal and pancreatic cancers has highlighted the promise of patient-derived organoids (PDOs) as a patient-proximate culture system, with an increasing number of models emerging. Similarly, work in other cancer types has focused on establishing organoid models and optimizing culture protocols. Notably, 3D cancer organoid models maintain the genetic complexity of original tumor specimens and thus translate tumor-derived sequencing data into treatment with genetically informed targeted therapies in an experimental setting. Further, PDOs might foster the evaluation of rational combination treatments to overcome resistance-associated adaptation of tumors in the future. The latter focuses on intense research efforts in non-small-cell lung cancer (NSCLC), as resistance development ultimately limits the treatment success of targeted inhibitors. An early assessment of therapeutically targetable mechanisms using NSCLC PDOs could help inform rational combination treatments. This manuscript describes a standardized protocol for the cell culture plate-based assessment of drug sensitivities to targeted inhibitors in NSCLC-derived 3D PDOs, with potential adaptability to combinational treatments and other treatment modalities.

This protocol describes a standardized evaluation of drug sensitivities to targeted signaling inhibitors in NSCLC patient-derived organoid models.

Novel 3D cancer organoid cultures derived from clinical patient specimens represent an important model system to evaluate intratumor heterogeneity and ...