Name: orthotopic transplantation of breast tumors as preclinical models for breast cancer
Uploaded: 2020-05-18T14:45:00
Description: Watch this Scientific Journal Video about Orthotopic Transplantation of Breast Tumors as Preclinical Models for Breast Cancer at JoVE.com

This work was supported by the National Institutes of Health (R37CA228304 and R01HL146642 to Xi Chen, CA148761 to Jeffrey M. Rosen), US Department of Defense (W81XWH-19-1-0524 to Xi Chen, W81XWH-19-1-0035 to Xiangdong Lv), American Cancer Society (RSG-18-181-01-TBE to Xi Chen) and Cancer Prevention and Research Institute of Texas (RR150009 CPRIT Scholar in Cancer Research Award to Xi Chen), the Patient-Derived Xenograft and Advanced In Vivo Models Core at Baylor College of Medicine (funding from RP170691 CPRIT Core Facility Award and NCI-CA125123 P30 Cancer Center Support Grant).

All protocols using animals have been reviewed and approved by the Institutional Animal Care and Use Committee (IACUC). The tumor fragments, around 1&#8722;2 mm3 in size, are from viably frozen stock obtained from the Patient-Derived Xenograft and Advanced In Vivo Models Core at Baylor College of Medicine.
1. Preparation of cryopreserved mammary tumor fragments for transplantation
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	<li>Transfer the cryovial with tumor fragments from liquid nitrogen to a 37 &#176;C water bath....

To reduce variations in tumor growth across animals, it is critical to cut the tumor tissue into 1 mm3 fragments for transplantation. Models that grow soft tissue are harder to work with and the tumor fragments need to be cut slightly larger (1&#8722;2 mm3). When placing the tissue into the mammary fat pad pocket take care not to split the tissue into multiple pieces as this will result in multiple small tumors or oddly shaped tumors.
In addition, use fresh tumor for tran...

Most breast cancer deaths can be ascribed to recurrent disease that is resistant to conventional therapies1,2. The inter- and intra-tumor heterogeneity of breast cancers contribute to therapy resistance. Moreover, tumor heterogeneity can impinge on accurate prognosis and challenge disease management3,4. Identification of predictive biomarkers of response will significantly improve clinical outcomes of patients with breast cancer. Even though most breast cancer types are immunologically &#39;cold&#39; tumors that are likely unresponsive to immunotherapy, immune checkpoint inhibitors have shown promise in clinical trials2,5. For example, a phase III trial showed improved disease-free survival (DFS) and preliminary evidence that atezolizumab (monoclonal antibody against PD-L1) combined with nab-paclitaxel may provide an overall survival benefit as compared with nab-paclitaxel alone in tumors with &#8805;1% PD-L1 staining6. Development of therapies that sensitize breast tumors to immunotherapy will revolutionize treatment regimens.
Preclinical models that faithfully recapitulate human breast cancer heterogeneity and drug response are critical to study tumor biology and identify potential biomarkers for targeted therapy. Immortalized cell lines are widely used for breast cancer research since these cell lines are easy to grow and genetically modify to study molecular mechanisms. However, due to the selective pressure from long term cell culture in vitro, genetic drift may occur over time and breast cancer cell lines may carry cell line-specific genomic alterations that are distinct from aberrations in primary breast tumors7,8,9.
Patient-derived xenograft (PDX) tumor chunks are able to recapitulate the heterogeneity of human disease, and are histologically and immunohistochemically similar to the tumor of origin10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29. Importantly, PDX models are phenotypically stable across multiple transplantations as evidenced by histology, transcriptome, proteome and genomic analysis10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29. PDX models show treatment responses comparable to those observed clinically10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29. PDX models for estrogen receptor positive (ER+), progesterone receptor positive (PR+), epidermal growth factor 2 positive (ERBB2+, HER2+) and triple negative breast cancer (TNBC) PDX models have been established, and provide an excellent platform to test endocrine-, chemo- and targeted therapies. However, one main caveat of PDX models at present is the lack of a functional immune system in the mouse.
The genetically engineered mouse models (GEMM), such as Trp53 homozygous null, cMyc, Wnt1, PyMT, or Her2 overexpression models, allow the study of spontaneous tumor initiation, progression and metastasis in the context of an intact immune system. However, the tumor latency is long, which makes it difficult to conduct preclinical trials with multiple arms30,31. However, GEMM can be transplanted to syngeneic hosts to generate sufficient numbers of tumors that closely recapitulate human tumors32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55. For example, the mammary epithelium from a p53-null BALB/c mouse was transplanted into the cleared fat pads of syngeneic wild-type recipient mice to form primary tumors, which can be further transplanted into syngeneic hosts56,57. The p53-null tumors recapitulated different subtypes of human tumors.
The combination of PDX models and transplantable GEMM provides valuable preclinical tools to investigate breast tumor biology, drug response and anti-tumor immunity. In the current protocol, a method of orthotopic transplantation of PDX and GEMM tumor fragments into the mouse mammary fat pad is described. These models are amenable for serial passages and usually retain a stable phenotype. To mitigate the risk of genetic drift or loss of heterogeneity across passages over time, multiple tissue fragments are cryopreserved at each passage for subsequent transplantation in the event that biological or morphological changes are observed over time29,58.

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			<td>Lubricant ophthalmic ointment</td>
			<td>Akorn Animal Health</td>
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			<td>Micro Dissecting Forceps; Serrated, Angular (regular forceps)</td>
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			<td>Micro Dissecting Spring Scissors (fat pad cutter)</td>
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			<td>Micro Forceps (tissue placing forceps)</td>
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			<td>Wound clip applier</td>
			<td>BD Autoclip Wound System</td>
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orthotopic transplantation of breast tumors as preclinical models for breast cancer

Preclinical models that faithfully recapitulate tumor heterogeneity and therapeutic response are critical for translational breast cancer research. Immortalized cell lines are easy to grow and genetically modify to study molecular mechanisms, yet the selective pressure from cell culture often leads to genetic and epigenetic alterations over time. Patient-derived xenograft (PDX) models faithfully recapitulate the heterogeneity and drug response of human breast tumors. PDX models exhibit a relatively short latency after orthotopic transplantation that facilitates the investigation of breast tumor biology and drug response. The transplantable genetically engineered mouse models allow the study of breast tumor immunity. The current protocol describes the method to orthotopically transplant breast tumor fragments into the mammary fat pad followed by drug treatments. These preclinical models provide valuable approaches to investigate breast tumor biology, drug response, biomarker discovery and mechanisms of drug resistance.

Figure 1 shows the equipment (Figure 1A) and key procedures (Figure 1B) of orthotopic transplantation. Figure 2 shows characterization of a transplanted PDX tumor (MC1). Tumor fragments (1 mm3) of MC1 model were transplanted into the #4 fat pad of SCID/Beige mice. One month later, the average tumor size reached around 350 mm<s...

Watch this Scientific Journal Video about Orthotopic Transplantation of Breast Tumors as Preclinical Models for Breast Cancer at JoVE.com

Orthotopic Transplantation of Breast Tumors as Preclinical Models for Breast Cancer

Patient-derived xenograft (PDX) models and transplantable genetically engineered mouse models faithfully recapitulate human disease and are preferred models for basic and translational breast cancer research. Here, a method is described to orthotopically transplant breast tumor fragments into the mammary fat pad to study tumor biology and evaluate drug response.

Preclinical models that faithfully recapitulate tumor heterogeneity and therapeutic response are critical for translational breast cancer research. ...

This protocol describes the orthotopic transplantation of breast tumor fragments into the mammary fat pad and provides valuable approaches for investigating tumor biology, drug responses, and mechanism of drug resistance. This technique is minimally invasive and ensures proper placement of the tumor tissues within the mammary fat pad, accessibility for counting per measurement, and animal mobility maintenance. This technique allows the transplantation of dozens of animals from a single patient derive's inter graft, for the evaluation of multiple candidate cancer therapies simultaneously in a preclinical trial format.This method is superior to subcutaneous tissue implantation for establishing patient derives inter-graph models, and can also be used when orthotopic implants are not possible. The most difficult stuffs are applying the appropriate amount of pressure to peel the fat pad from the body wall and making the tissue pocket. Visualization of the fat pad peeling and the cracked anatomical placement of the tissue fragment, will help you ensure a successful performance of the procedure.To thaw cryopreserved mammary tumor tissue fragments for transplantation. First, thaw a cryo vial from liquid Nitrogen storage containing the tumor fragments of interest in a 37 degrees Celsius water bath, with occasional gentle flicking. When the fragments have thawed, mix the fragments with gentle inversion, and dry the outside of the vial.Spray the vial with 70%ethanol, and place it in a vial-safety hood. Transfer the cryo vial contents to a 15 milliliter conical tube. Then add 10 milliliters of cold DMEM, and invert the tube to mix.Allow the fragments to settle, and replace a supernatant two times with 10 milliliter aliquot, so, fresh cold DMEM. Then place the tube on ice. To collect a mammary tumor tissue sample, spray the tumor region of the tumor bearing mouse with 70%ethanol and use serrated forceps to pinch and lift the skin surrounding the tumor.Use scissors to make a small incision, and separate the tumor from the skin, taking care to avoid hair contamination. Trim off any remaining mouse fat pad tissue from the outer surface of the tumor, and place the tumor in a 15 milliliter conical tube containing five milliliters of cold DMEM. In a bio-safety hood transfer the dissected tumor into a sterile 10 centimeter Petri dish, containing enough DMEM to prevent drying, and use a UV sterilized blade to cut the tumor into one cubed millimeter fragments under aseptic conditions.Then transfer the tumor fragments to a 15 milliliter tube containing cold DMEM on ice. After confirming a lack of response to pedal reflex, apply ointment to the anesthetized recipient mouse's eyes, and shave the abdomen around the fourth memory gland. Then disinfect the exposed skin three times, using a circular motion and starting in the center of the surgery site while moving outward toward the outer edges, with povidone-iodine surgical scrub, followed by scrub removal with a 70%isopropyl alcohol pad.For transplantation of the tumor tissue fragments, into the fourth inguinal mammary fat pad, cover the animal with a sterile fenestrated surgical drape, and use serrated forceps to pinch and lift the skin at the fourth nipple. With the blunt side of the tips facing down, use scissors to make an approximately one centimeter parasagittal incision from the number four nipple toward the head. Use a cotton tip applicator to separate the skin from the peritoneum on the medial side of the incision, and gently peel the number four memory fat pad from the skin.Use a sterile 27 gauge needle to secure the skin close to the animal's body, and use serrated forceps to gently extend the fat pad away from the body. Locate the inguinal lymph node at the intersection of the major vessels of the gland, and carefully cauterize the vessels medial to the lymph node and the fat adjoining the fourth and fifth fat pads. Using micro dissecting scissors, cut each cauterized vessel one at a time, til the section of the fat pad that contains the lymph node is removed, and use blunt forceps to grasp the fat pad.Using the other hand and a curved motion, insert the close tip of a pair of angled fine forceps into the middle of the fat pad above the remaining vessel close to the wall of the peritenoneum. Retract the tips and reinsert the tips into the original hole, opening the forceps to stretch the hole into a small pocket. Remove the forceps from the hole and use them to insert a piece of tumor fragment into the pocket.Slowly open the tips to release the tumor fragment into the fat pad pocket and carefully withdraw the forceps. After confirming that the fragment has been deposited into the fat pad pocket, starting from the base of the incision, collect the on each side of the incision with serrated forceps and lift the skin slightly. Uncurl the edges of the incision with claw forceps and pinch the edges together to form a continuous surface at the top.Holding the two sides with the serrated forceps, use a wound clip applicator to place a clip in the center of the incision, and place the animal in a clean cage on a warming surface with monitoring until full recumbency. Typically, patient derived xenograft or genetically engineered mouse model tumors can be palpated from about two to eight weeks post transplantation. H&E staining can be performed to analyze the tumor pathology while immunohistochemistry can be used to monitor markers for a specific cell lineages of interest, or cell viability and functional status.It is important to make sure that the tumor fragment is placed securely in the pocket, so, that it doesn't fall out and grow within the subcutaneous space. Once the tumors have grown, drug treatment can be administered to assess tumor responses. The tumors can also be removed to determine the metastatic potential of the cancer cells.This basic technique has been used since the 1950s. Our modification provides a more efficient and less invasive manner in which to conduct larger scale developmental biology in cancer studies.

orthotopic-transplantation-breast-tumors-as-preclinical-models-for

Research

JoVE Journal

Cancer Research

Utilizing Functional Genomics Screening to Identify Potentially Novel Drug Targets in Cancer Cell Spheroid Cultures

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery of the next generation of novel drug targets. It is becoming apparent that more complex models of cancer are required to fully appreciate the contributing factors that drive tumorigenesis in vivo and increase the efficacy of novel therapies that make the transition from pre-clinical models to clinical trials.
Here we present a methodology for generating uniform and reproducible tumor spheroids that can be subjected to siRNA functional screening. These spheroids display many characteristics that are found in solid tumors that are not present in traditional two-dimension culture. We show that several commonly used breast cancer cell lines are amenable to this protocol. Furthermore, we provide proof-of-principle data utilizing the breast cancer cell line BT474, confirming their dependency on amplification of the epidermal growth factor receptor HER2 and mutation of phosphatidylinositol-4,5-biphosphate 3-kinase (PIK3CA) when grown as tumor spheroids. Finally, we are able to further investigate and confirm the spatial impact of these dependencies using immunohistochemistry.

Identifying novel drug targets that transition from pre-clinical testing to human trials is a scientific priority. To that end, here we describe a functional genomics approach for examining the impact of gene depletion on cancer cell line spheroids, which more appropriately model human cancers in vivo.

The identification of functional driver events in cancer is central to furthering our understanding of cancer biology and indispensable for the discovery ...

Ultrasonographic Evaluation of Breast Cancer-related Lymphedema

Lymphedema is one of the most common complications after breast cancer surgery. There are many diagnostic tools for lymphedema, but no standard method yet exists. Progressive Resistance Exercise (PRE) is expected to improve lymphedema without additional swelling. This study showed the therapeutic effects of PRE on lymphedema by using ultrasonography to measure the change in thickness of the muscle and subcutaneous tissue. The thickness of subcutaneous tissue decreased more in the PRE group than in the non-PRE group. Ultrasonography is widely used in many clinics because of its easy accessibility, safety, and inexpensiveness. Ultrasound is one of the best tools for diagnosing and determining treatment efficacy on breast cancer-related lymphedema (BCRL).

This study utilized ultrasonography for diagnosis and follow-up tests to confirm treatment efficacy of Progressive Resistance Exercise (PRE) in breast cancer-related lymphedema (BCRL). Ultrasonography can be applied effectively to ensure diagnosis and treatment of lymphedema.

Lymphedema is one of the most common complications after breast cancer surgery. There are many diagnostic tools for lymphedema, but no standard method yet ...

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 ...

Development of a Human Preclinical Model of Osteoclastogenesis from Peripheral Blood Monocytes Co-cultured with Breast Cancer Cell Lines

The crosstalk between tumor cells and bone cells in the bone microenvironment is crucial to understanding the mechanism of bone metastasis formation. We developed an in vitro fully human preclinical model of a co-culture of breast cancer cells and monocytes undergoing differentiation towards osteoclasts. We optimized a model of osteoclastogenesis starting from a sample of peripheral blood collected from healthy donors. Peripheral blood mononuclear cells (PBMCs) were first separated by density gradient centrifugation, seeded at a high density and induced to differentiate by adding two growth factors (GFs): receptor activator of nuclear factor-&#954;B ligand (RANKL) and macrophage colony-stimulating factor (MCSF). The cells were left in culture for 14 days and then fixed and analyzed by downstream analysis. In osteolytic bone metastases, one of the effects of cancer cell arrival in bone is the induction of osteoclastogenesis. We thus challenged our model with co-cultures of breast cancer cells to study the differentiation power of cancer cells with respect to GFs. A straightforward way of studying cancer cell-osteoclast interaction is to perform indirect co-cultures based on the use of conditioned medium collected from breast cancer cell cultures and mixed with fresh medium. This mixture is then used to induce osteoclast differentiation. We also optimized a method of direct co-culture in which cancer cells and monocytes undergoing differentiation share the medium and exchange secreted factors. This is a significant improvement over the original indirect co-culture method as researchers can observe the reciprocal interactions of the two cell types and perform downstream analyses for both cancer cells and osteoclasts. This method enables us to study the effect of drugs on the metastatic bone microenvironment and to seed cell lines other than those derived from breast cancer. The model can also be used to study other diseases such as osteoporosis or other bone conditions.

This protocol describes development of an in vitro human preclinical model of osteoclastogenesis from peripheral blood monocytes cultured with breast cancer cell lines to mimic the cancer cell-osteoclast interaction. The model could be used to further our understanding of bone metastasis formation and improve therapeutic options.

The crosstalk between tumor cells and bone cells in the bone microenvironment is crucial to understanding the mechanism of bone metastasis formation. We ...

The Application of 1% Methylene Blue Dye As a Single Technique in Breast Cancer Sentinel Node Biopsy

In this study, we injected 1% methylene blue dye (MBD) into the subareolar or peritumoral space of the breast. In the case of breast conserving surgery (BCS), a separate incision in the lower axilla hairline was made to find the sentinel nodes (SNs). In mastectomy, the SNs were identified through the same mastectomy incision. The SNs were described as blue nodes or nodes with lymphatic blue channels. An anatomical landmark in the axilla was used to facilitate SNs identification. The SNs metastases were evaluated by intraoperative frozen section analysis and histopathology examination as it is a gold standard. Here, we described the MBD as the lone technique in breast cancer sentinel node biopsy (SNB) which could be useful when radioisotope tracer or patent or isosulfan blue dye (PBD) cannot be provided.

In Indonesia, sentinel node biopsy (SNB) is not routinely performed for breast cancer surgery because of the limitation to provide radioisotope tracer and isosulfan or patent blue dye (PBD). To overcome this obstacle, we applied 1% methylene blue dye (MBD) as a single agent to map the sentinel nodes (SNs).

In this study, we injected 1% methylene blue dye (MBD) into the subareolar or peritumoral space of the breast. In the case of breast conserving surgery ...

Orthotopic Injection of Breast Cancer Cells into the Mice Mammary Fat Pad

A proper animal model is crucial for a better understanding of diseases. Animal models established by different methods (subcutaneous injections, xenografts, genetic manipulation, chemical reagents induction, etc.) have various pathological characters and play important roles in investigating certain aspects of diseases. Although no single model can totally mimic the whole human disease progression, orthotopic organs disease models with a proper stromal environment play an irreplaceable role in understanding diseases and screening for potential drugs. In this article, we describe how to implant breast cancer cells into the mammary fat pad in a simple, less invasive, and easy-to-handle way, and follow the metastasis to distant organs. With the proper features of primary tumor growth, breast and nipple pathological changes, and a high occurrence of other organs&#39; metastasis, this model maximumly mimics human breast cancer progression. Primary tumor growth in situ, long-distant metastasis, and the tumor microenvironment of breast cancer can be investigated by using this model.

Here, we present a protocol to implant breast cancer cells into the mammary fat pad in a simple, less invasive, and easy-to-handle way, and this mouse orthotopic breast cancer model with a proper mammary fat pad environment can be used to investigate various aspects of cancer.

A proper animal model is crucial for a better understanding of diseases. Animal models established by different methods (subcutaneous injections, ...

Obtaining Cancer Stem Cell Spheres from Gynecological and Breast Cancer Tumors

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

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

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

Studying Triple Negative Breast Cancer Using Orthotopic Breast Cancer Model

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited therapeutic options. When compared to patients with less aggressive breast tumors, the 5-year survival rate of TNBC patients is 77% due to their characteristic drug-resistant phenotype and metastatic burden. Toward this end, murine models have been established aimed at identifying novel therapeutic strategies limiting TNBC tumor growth and metastatic spread. This work describes a practical guide for the TNBC orthotopic model where MDA-MB-231 breast cancer cells suspended in a basement membrane matrix are implanted in the fourth mammary fat pad, which closely mimics the cancer cell behavior in humans. Measurement of tumors by caliper, lung metastasis assessment via in vivo and ex vivo imaging, and molecular detection are discussed. This model provides an excellent platform to study therapeutic efficacy and is especially suitable for the study of the interaction between the primary tumor and distal metastatic sites.

This work presets an advanced protocol to accurately assess tumor loading by detection of green fluorescent protein and bioluminescence signals as well as the integration of quantitative molecular detection technique.

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited therapeutic options. When compared to patients with less ...

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The orthotopic murine model can be performed on large cohorts of immunocompetent mice simultaneously, is relatively inexpensive and preserves the cognate tissue microenvironment. The quantification of T cell infiltration and cytotoxic activity within orthotopic tumors provides a useful indicator of an antitumoral response.
This protocol describes the methodology for surgical generation of orthotopic pancreatic tumors by injection of a low number of syngeneic tumor cells resuspended in 5 &#181;L basement membrane directly into the pancreas. Mice bearing orthotopic tumors take approximately 30 days to reach endpoint, at which point tumors can be harvested and processed for characterization of tumor-infiltrating T cell activity. Rapid enzymatic digestion using collagenase and DNase allows a single-cell suspension to be extracted from tumors. The viability and cell surface markers of immune cells extracted from the tumor are preserved; therefore, it is appropriate for multiple downstream applications, including flow-assisted cell sorting of immune cells for culture or RNA extraction, flow cytometry analysis of immune cell populations. Here, we describe the ex vivo stimulation of T cell populations for intracellular cytokine quantification (IFN&#947; and TNF&#945;) and degranulation activity (CD107a) as a measure of overall cytotoxicity. Whole-tumor digests were stimulated with phorbol myristate acetate and ionomycin for 5 h, in the presence of anti-CD107a antibody in order to upregulate cytokine production and degranulation. The addition of brefeldin A and monensin for the final 4 h was performed to block extracellular transport and maximize cytokine detection. Extra- and intra-cellular staining of cells was then performed for flow cytometry analysis, where the proportion of IFN&#947;+, TNF&#945;+ and CD107a+ CD4+ and CD8+ T cells was quantified.
This method provides a starting base to perform comprehensive analysis of the tumor microenvironment.

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

This protocol describes the surgical generation of orthotopic pancreatic tumors and the rapid digestion of freshly isolated murine pancreatic tumors. Following digestion, viable immune cell populations can be used for further downstream analysis, including ex vivo stimulation of T cells for intracellular cytokine detection by flow cytometry.

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The ...

Modeling Breast Cancer in Human Breast Tissue using a Microphysiological System

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs fail clinical trials. Therefore, new models are needed to improve our understanding of the disease. The NIH Microphysiological Systems (MPS) program was developed to improve the clinical translation of basic science discoveries and promising new therapeutic strategies. Here we present a method for generating MPS for breast cancers (BC-MPS). This model adapts a previously described approach of culturing primary human white adipose tissue (WAT) by sandwiching WAT between adipose-derived stem cell sheets (ASC)s. Novel aspects of our BC-MPS include seeding BC cells into non-diseased human breast tissue (HBT) containing native extracellular matrix, mature adipocytes, resident fibroblasts, and immune cells; and sandwiching the BC-HBT admixture between HBT-derived ASC sheets. The resulting BC-MPS is stable in culture ex vivo for at least 14 days. This model system contains multiple elements of the microenvironment that influence BC including adipocytes, stromal cells, immune cells, and the extracellular matrix. Thus BC-MPS can be used to study the interactions between BC and its microenvironment. 
We demonstrate the advantages of our BC-MPS by studying two BC behaviors known to influence cancer progression and metastasis: 1) BC motility and 2) BC-HBT metabolic crosstalk. While BC motility has previously been demonstrated using intravital imaging, BC-MPS allows for high-resolution time-lapse imaging using fluorescence microscopy over several days. Furthermore, while metabolic crosstalk was previously demonstrated using BC cells and murine pre-adipocytes differentiated into immature adipocytes, our BC-MPS model is the first system to demonstrate this crosstalk between primary human mammary adipocytes and BC cells in vitro.

This protocol describes the construction of an in vitro microphysiological system for studying breast cancer using primary human breast tissue with off the shelf materials.

Breast cancer (BC) remains a leading cause of death for women. Despite more than $700 million invested in BC research annually, 97% of candidate BC drugs ...