The authors would like to thank the National Natural Science Foundation of China (grant no. 81873111, 81673924, 81774039, 81503517), the Beijing Natural Science Foundation (grant no. 7172095, 7162084, 7162083), and the Xu Xia Foundation of the Beijing Hospital of Traditional Chinese Medicine (grant no, xx201701).&#160;We thank Prof. Chang-Zhen Liu, from Experimental Research Center, China&#160;Academy of Chinese Medical Sciences, for bioluminescent images.

Animal experiments were conducted in accordance with the Provision and General Recommendation of Chinese Experimental Animal Administration Legislation and were approved by the Institution of Animal Care and Use Committee of Capital Medical University (Ref no. AEEI-2014-052). Female Balb/c mice aged 6 to 8 weeks were used.
1. Preparation of the Cells and Animals
<ol>
	<li>One day before the operation, shave the hair around the fourth nipples to expose the operating area.
	<ol>
		<li>Use one hand to hold the mouse tightly at the back to make sure the mouse will not move freely, turn up the mouse to expose its belly to the operator, and then use another hand to shave the fur around the fourth nipples with an electronic shaver.</li>
		<li>Put a thin layer of hair removal cream around the nipples for 30 - 60 s, clean away the cream with distilled water, and then dry the mouse with soft paper.</li>
	</ol>
	</li>
	<li>On the day of the operation, collect murine breast cancer cells (4T1-luc2), count the cell number, and adjust the cell density to 2 x 105 cells/mL in phosphate-buffered saline (PBS) in sterile microcentrifuge tubes and keep them on ice. For each mouse, 1 x 104 cells/50 &#181;L in a 1-mL syringe is prepared.</li>
</ol>
2. Orthotopic Injection
<ol>
	<li>Anesthesia of mice 
	<ol>
		<li>Induce anesthesia. Put the mice in a closed transparent container and turn on 2% isoflurane gas to anesthetize the mice for about 5 min, till they all lie down and fall asleep.</li>
		<li>Maintain anesthesia. Transfer the mice from the container to individual anesthesia masks, put some vet ointment on their eyes to avoid dryness, keep the mice supinely with their nipples exposed to the operator, and let them continue to inhale isoflurane gas for a few minutes until the injection has been performed.</li>
		<li>Confirm the success of anesthesia by the lack of a toe pinch withdrawal reflex.</li>
		<li>Apply ophthalmic ointment to the eyes of the mice to prevent eye dryness. 
		Note: According to the container size and the number of individual anesthesia masks available, a group of mice can be anesthetized together and injected one by one under individual anesthesia.</li>
	</ol>
	</li>
	<li>Performance of the injection
	<ol>
		<li>Use one hand to tent up the skin around the fourth nipple with tweezers, to set up an uplifted &#8220;tunnel&#8221; for the syringe to follow. Use the other hand to hold the syringe with the needle turned upwards to enter the skin subcutaneously at 5 - 10 mm from nipple; then, follow the &#8220;tunnel&#8221; until the needle tip comes close to the nipple, carefully move the needle tip up into the mammary fat pad till the needle eye comes under the nipple tip, discard the tweezers, and inject the cells slowly.</li>
		<li>Turn around the needle a little and retract the syringe slowly; use a cotton swab to press the needle wound for 10 - 20 s to make sure there is no fluid seepage.</li>
		<li>Observe the fourth nipple to confirm a successful injection: one white transparent flat sphere with the nipple as the center can be observed (Figure 1).</li>
	</ol>
	</li>
	<li>Keep the mice anesthetized for another minute to avoid letting the mice recover and move too quickly, which will cause the injection wound to open and the tumor cells to leak out.</li>
</ol>
3. Analysis of the Tumor Growth and Metastasis
Note: Primary tumors are identified as transparent or blister-like bumps after injections, and as spherical or ellipsoid solid lumps with the nipple a few days later. Tumor growth is evaluated by tumor volume and tumor bioluminescence.
<ol>
	<li>To establish the tumor volume, hold the mouse with one hand. Expose its belly to the operator and use the other hand to caliper the tumor length (L) and width (W). Calculate the tumor volume (V) as follows. 
	V = (L x W2)/2</li>
	<li>To capture the tumor bioluminescence, inject 150 mg/kg D-luciferin at the back of the mouse&#8217;s neck, 10 min before imaging. Anesthetize the mice with 2% isoflurane gas for 5 min and transfer them to individual anesthesia masks to let them inhale isoflurane gas for 5 min longer. Following the manufacturer&#8217;s instructions, capture bioluminescence images of the primary tumor and metastasis, with auto exposure time, medium binning, and f/stop at 1.</li>
</ol>
4. Harvesting of the Primary Tumor and Metastasis Organs for Analysis
Note: When achieving the purpose of this experiment, or reaching the humane endpoint, the primary tumor can be harvested for further study. In this study, tumors are removed at 4 to 5 weeks after the injection, when the tumor volume reaches about 800 mm3. The lungs are removed at week 8.
<ol>
	<li>Harvesting of the primary tumor
	<ol>
		<li>Perform the surgery in a sterile hood to maintain a sterile atmosphere. Anesthetize the animals by isoflurane. Confirm the success of anesthesia by the lack of toe pinch withdrawal reflexes. Apply ophthalmic ointment to the eyes of the mice to prevent them from drying out.</li>
		<li>Dissociate the tumor from the skin with scissors, dropwise painkiller (1 mg/mL tramadol, 1 drop of about 50 &#181;L per mouse) to&#160;relieve postoperative pain.</li>
		<li>Stitch the skin with a surgical suture, cut off excess suture, drape off the incision.</li>
		<li>Cut the primary tumor in half with a scalpel, put 1/2 of the tumor into 4% paraformaldehyde for further hematoxylin and eosin (H&#38;E) staining and immunohistochemistry, and immediately freeze the other 1/2 with liquid nitrogen for western blotting or an RNA isolation study later.</li>
		<li>After suturing, warm the mice with a lamp till they recover, keep the mice in single cages until fully recovered. Continuously&#160;administer 10 mg/kg tramadol with an oral gavage for 3 d after the surgery.</li>
	</ol>
	</li>
	<li>Harvesting of metastasis organs
	<ol>
		<li>Euthanize the mice with an overdose of pentobarbital, open their chests with scissors, gently take out the lungs, and wash them with PBS. Lung metastasis foci can be identified as white transparent bumps which are morphologically different and distinguishable from normal pink lung tissue.</li>
		<li>Put the lungs into 4% paraformaldehyde to verify the metastasis by H&#38;E staining.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

The cells used in this study are 4T1-luc2, murine triple-negative breast cancer cells with luciferase labeling, which are a useful tool for investing antitumor and antimetastatic effects of drugs due to their highly invasive nature2,19. Luciferases, stable to the next cell generation, are used to indicate the living tumor cells, both at the mammary gland and at other distant organs20. In some cases, hypoxia and nutrient deficiency within t...

Breast cancer is the leading cause of female mortality worldwide. With its progressively increasing incidence, breast cancer has become a serious challenge to public health1. Murine cancer models are good bridges between preclinical and clinical studies, and a good mimic murine disease model will increase the accuracy of research on disease and medicine.
Primary tumor growth starts the progress of malignant disease, while metastasis and complications are the main causes of death and poor life qualities in most cancer patients. Several murine models are used to mimic the pathology of human breast cancer2,3,4. Xenograft models are widely used for cancer study to understand the pathological characters and to screen drugs for safety and efficacy5,6,7. Genetically engineered mice (GEM) are generated to mimic human breast cancer by targeting certain oncogenes or tumor suppressor genes8. GEM have a relatively simple and uniformed background to understand the role of genes in cancerous progress; however, the artificial environment and background are limited to investigate the metastasis pathology and related therapies9. Human cancer cells, although with human pathological features, can only be implanted in immune-deficient mice, and the insufficiency of the tumor-host immune interaction may lead to biased results10.
Where the solid tumor initiates has a direct influence on the biological and pathological characters of the disease11,12,13. Since cancerous progress is the complicated outcome of interactions among tumor cells, stromal cells, immunology cells, inflammatory cells, growth factors, and proteases, primary tumors implanted in situ will provide better insight and mimic the cancerous process more accurately than tumors induced by chemical agents or a subcutaneous injection of tumor cells. Chemical agents used to induce tumors may be harmful to researchers and environment and are even forbidden in some countries. Because of the absence of a mammary fat pad environment, the pathological progress of a subcutaneous injection may differ with that in real breast cancer patients, whose cancer originates and irritates from the mammary fat pad. The disadvantages of subcutaneous injections encourage the use of orthotopic models to study tumor growth. In earlier research, highly metastatic MDA-MB-231 tumors, developed after seven orthotopic transplantations, indicated the importance of the injection location14. Recently, the orthotopic implantation of breast cancer cells into the mammary fat pad with surgery was reported15,16. With the mammary pad environment, the tumor growth and the migration into distant organs cover the entire process of breast cancer at pathologically relevant sites, which makes this model a miniature of the progress of human diseases. However, after the surgery, the skin automatically attempts to heal itself, which may bring the potential risk of interfering with the normal breast cancer origination and bias the results.
We have compared some breast cancer models and established a minimally invasive orthotopic model to investigate the potential effect of drugs on breast cancer progression17,18. In this study, a video protocol on how to orthotopically inject breast cancer cells into the mammary fat pad in a simple, less invasive way is presented. This orthotopic injection method without surgery is advantageous in many ways. First, the operation is simple and rapid, about 1 minute per mouse. Second, with primary tumor foci starting at the right pathological sites, it covers the whole tumorigenic process of breast cancer progression from the tumor growth to other organs metastasis, which provides a good experimental animal model for studying the interaction of tumor cells and tumor microenvironment. Besides, it can be a valuable model to estimate the treatment effects at all stages of breast cancer. The goal of this method is to provide an animal model to maximumly mimic human breast cancer progression.

<table border="0" cellpadding="0" cellspacing="0" style="width:652px;" width="653">
	<tbody>
		<tr height="48">
			<td height="48" style="height:49px;width:149px;">anesthesia machine</td>
			<td style="width:235px;">Midmark Corporation, Dayton, OH, USA</td>
			<td style="width:96px;">Matrx VMS</td>
			<td style="width:172px;">anesthesia</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:149px;">In-Vivo Imaging System</td>
			<td style="width:235px;">PerkinElmer</td>
			<td style="width:96px;">IVIS Spectrum</td>
			<td style="width:172px;">used for bioluminescence detecion</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:43px;width:149px;">&#160;isoflurane</td>
			<td style="width:235px;">Hebei yipin chemical reagents&#160; company</td>
			<td style="width:96px;">O21400</td>
			<td style="width:172px;">anesthesia</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:149px;">1 ml syringe</td>
			<td style="width:235px;">Becton,Dickinson and&#160; Company</td>
			<td style="width:96px;">A257</td>
			<td style="width:172px;">cell injection</td>
		</tr>
		<tr height="48">
			<td height="48" style="height:49px;width:149px;">digital caliper</td>
			<td style="width:235px;">Shang Hai Shen Han Measuring Tools Co., Ltd.</td>
			<td style="width:96px;">S-H</td>
			<td style="width:172px;">volume measurement</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:149px;">tramadol</td>
			<td style="width:235px;">Mundipharma company</td>
			<td style="width:96px;">-</td>
			<td style="width:172px;">pain killer</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:149px;">D-luciferin</td>
			<td style="width:235px;">Gold Biotechnology Inc.</td>
			<td style="width:96px;">LUCK-1G</td>
			<td style="width:172px;">used for bioluminescence detecion</td>
		</tr>
		<tr height="51">
			<td height="51" style="height:52px;width:149px;">The primary antibody against cluster of differentiation (CD) 31</td>
			<td style="width:235px;">Abcam</td>
			<td style="width:96px;">&#160;ab28364</td>
			<td style="width:172px;">used for MVD detection</td>
		</tr>
		<tr height="66">
			<td height="66" style="height:67px;width:149px;">hematoxylin and eosin staining kit</td>
			<td style="width:235px;">&#160;Beijing Zhong Shan Jinqiao Biotechnology Co., Ltd.</td>
			<td style="width:96px;">ZLI-9615</td>
			<td style="width:172px;">histology&#160;</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:149px;">hair removal cream</td>
			<td style="width:235px;">Veet</td>
			<td style="width:96px;">-</td>
			<td style="width:172px;">hair removal cream</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:47px;width:149px;">Carbomer Eye Gel</td>
			<td style="width:235px;">Dr.GerhardMannChem-Pharm.FabrikGmbH</td>
			<td style="width:96px;">-</td>
			<td style="width:172px;">ophthalmic ointment</td>
		</tr>
		<tr height="59">
			<td height="59" style="height:59px;">sewing needle</td>
			<td style="width:235px;">Shanghai Pudong Jinhuan Medical Products Co., Ltd.&#160;</td>
			<td>17U0302J</td>
			<td style="width:172px;">suture</td>
		</tr>
	</tbody>
</table>

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.

After a successful injection, one white transparent flat sphere with the nipple as the out-surface round center can be observed (Figure 1). Primary tumor growth can be measured by tumor volume and living tumor cell bioluminescence (Figure 2). Both the tumor volume and the total flux increased during the experiment before resection. At an early stage, metastasis cannot be found because no secondary tumor has happened or the strong...

Watch this Scientific Journal Video about Orthotopic Injection of Breast Cancer Cells into the Mice Mammary Fat Pad at JoVE.com

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

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, ...

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50.0K Views.  Capital Medical University. 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.

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

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 ...

A Portal Vein Injection Model to Study Liver Metastasis of Breast Cancer

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Liver metastasis is involved in upwards of 30% of cases with breast cancer metastasis, and results in poor outcomes with median survival rates of only 4.8 - 15 months. Current rodent models of breast cancer metastasis, including primary tumor cell xenograft and spontaneous tumor models, rarely metastasize to the liver. Intracardiac and intrasplenic injection models do result in liver metastases, however these models can be confounded by concomitant secondary-site metastasis, or by compromised immunity due to removal of the spleen to avoid tumor growth at the injection site. To address the need for improved liver metastasis models, a murine portal vein injection method that delivers tumor cells firstly and directly to the liver was developed. This model delivers tumor cells to the liver without complications of concurrent metastases in other organs or removal of the spleen. The optimized portal vein protocol employs small injection volumes of 5 - 10 &#956;l, &#8805; 32 gauge needles, and hemostatic gauze at the injection site to control for blood loss. The portal vein injection approach in Balb/c female mice using three syngeneic mammary tumor lines of varying metastatic potential was tested; high-metastatic 4T1 cells, moderate-metastatic D2A1 cells, and low-metastatic D2.OR cells. Concentrations of &#8804; 10,000 cells/injection results in a latency of ~ 20 - 40 days for development of liver metastases with the higher metastatic 4T1 and D2A1 lines, and &#62; 55 days for the less aggressive D2.OR line. This model represents an important tool to study breast cancer metastasis to the liver, and may be applicable to other cancers that frequently metastasize to the liver including colorectal and pancreatic adenocarcinomas.

A surgical procedure was developed to deliver mammary tumor cells to the murine liver via portal vein injection. This model permits investigation of late stages of liver metastasis in a fully immune competent host, including tumor cell extravasation, seeding, survival, and metastatic outgrowth in the liver.

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Liver metastasis is involved in upwards of 30% of cases with breast ...

Flow Cytometric Detection of Newly-formed Breast Cancer Stem Cell-like Cells After Apoptosis Reversal

Cancer recurrence has long been studied by oncologists while the underlying mechanisms remain unclear. Recently, we and others found that a phenomenon named apoptosis reversal leads to increased tumorigenicity in various cell models under different stimuli. Previous studies have been focused on tracking this process in vitro and in vivo; however, the isolation of real reversed cells has yet to be achieved, which limits our understanding on the consequences of apoptosis reversal. Here, we take advantage of a Caspase-3/7 Green Detection dye to label cells with activated caspases after apoptotic induction. Cells with positive signals are further sorted out by fluorescence-activated cell sorting (FACS) for recovery. Morphological examination under confocal microscopy helps confirm the apoptotic status before FACS. An increase in tumorigenicity can often be attributed to the elevation in the percentage of cancer stem cell (CSC)-like cells. Also, given the heterogeneity of breast cancer, identifying the origin of these CSC-like cells would be critical to cancer treatment. Thus, we prepare breast non-stem cancer cells before triggering apoptosis, isolating caspase-activated cells and performing the apoptosis reversal procedure. Flow cytometry analysis reveals that breast CSC-like cells re-appear in the reversed group, indicating breast CSC-like cells are transited from breast non-stem cancer cells during apoptosis reversal. In summary, this protocol includes the isolation of apoptotic breast cancer cells and detection of changes in CSC percentage in reversed cells by flow cytometry.

Here, we present a protocol to isolate apoptotic breast cancer cells by fluorescence-activated cell sorting and further detect the transition of breast non-stem cancer cells to breast cancer stem cell-like cells after apoptosis reversal by flow cytometry.

Cancer recurrence has long been studied by oncologists while the underlying mechanisms remain unclear. Recently, we and others found that a phenomenon ...

Modeling Breast Cancer via an Intraductal Injection of Cre-expressing Adenovirus into the Mouse Mammary Gland

Breast cancer is a heterogeneous disease, possibly due to complex interactions between different cells of origins and oncogenic events. Mouse models are instrumental in gaining insights into these complex processes. Although many mouse models have been developed to study contributions of various oncogenic events and cells of origin to breast tumorigenesis, these models are often not cell-type or organ specific or cannot induce the initiation of mammary tumorigenesis in a temporally controlled manner. Here we describe a protocol to generate a new type of breast cancer mouse models based on the intraductal injection of Cre-expressing adenovirus (Ad-Cre) into mouse mammary glands (MGs). Due to the direct injection of Ad-Cre into mammary ducts, this approach is MG specific, without any unwanted cancer induction in other organs. The intraductal injection procedure can be performed in mice at different stages of their MG development (thus, it permits temporal control of cancer induction, starting from ~3-4 weeks of age). The cell-type specificity can be achieved by using different cell-type-specific promoters to drive Cre expression in the adenoviral vector. We show that luminal and basal mammary epithelial cells (MECs) can be tightly targeted for Cre/loxP-based genetic manipulation via an intraductal injection of Ad-Cre under the control of the Keratin 8 or Keratin 5 promoter, respectively. By incorporating a conditional Cre reporter (e.g., Cre/loxP-inducible Rosa26-YFP reporter), we show that MECs targeted by Ad-Cre, and tumor cells derived from them, can be traced by following the reporter-positive cells after intraductal injection.

The goal of this protocol is to describe a new breast cancer modeling approach based on the intraductal injection of Cre-expressing adenovirus into mouse mammary glands. This approach allows both cell-type- and organ-specific manipulation of oncogenic events in a temporally controlled manner.

Breast cancer is a heterogeneous disease, possibly due to complex interactions between different cells of origins and oncogenic events. Mouse models are ...

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 ...

Rat Mammary Epithelial Cell Transplantation into the Interscapular White Fat Pad

As early as the 1970s, researchers have successfully transplanted mammary epithelial cells into the interscapular white fat pad of rats. Grafting mammary epithelium using transplantation techniques takes advantage of the hormonal environment provided by the adolescent rodent host. These studies are ideally suited to explore the impact of various biological manipulations on mammary gland development and dissect many aspects of mammary gland biology. A common, but limiting, feature is that transplanted epithelial cells are strongly influenced by the surrounding stroma and outcompeted by endogenous epithelium; to utilize native mammary tissue, the abdominal-inguinal white fat pad must be cleared to remove host mammary epithelium prior to the transplantation. A major obstacle when using the rat model organism is that clearing the developing mammary tree in post-weaned rats is not efficient. When transplanted into gland-free fat pads, donor epithelial cells can repopulate the cleared host fat pad and form a functional mammary gland. The interscapular fat pad is an alternative location for these grafts. A major advantage is that it lacks ductal structures yet provides the normal stroma that is necessary to promote epithelial outgrowth and is easily accessible in the rat. Another major advantage of this technique is that it is minimally invasive, because it eliminates the need to cauterize and remove the growing endogenous mammary tree. Additionally, the interscapular fat pad contains a medial blood vessel that can be used to separate sites for grafting. Because the endogenous glands remain intact, this technique can also be used for studies comparing the endogenous mammary gland to the transplanted gland. This paper describes the method of mammary epithelial cell transplantation into the interscapular white fat pad of rats.

This article describes a transplantation method to graft donor rat mammary epithelial cells into the interscapular white fat pad of recipient animals. This method can be used to examine host and/or donor effects on mammary epithelium development and eliminates the need for pre-clearing, thereby extending the usefulness of this technique.

As early as the 1970s, researchers have successfully transplanted mammary epithelial cells into the interscapular white fat pad of rats. Grafting mammary ...

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.

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. ...

Modeling Brain Metastasis Via Tail-Vein Injection of Inflammatory Breast Cancer Cells

Metastatic spread to the brain is a common and devastating manifestation of many types of cancer. In the United States alone, about 200,000 patients are diagnosed with brain metastases each year. Significant progress has been made in improving survival outcomes for patients with primary breast cancer and systemic malignancies; however, the dismal prognosis for patients with clinical brain metastases highlights the urgent need to develop novel therapeutic agents and strategies against this deadly disease. The lack of suitable experimental models has been one of the major hurdles impeding advancement of our understanding of brain metastasis biology and treatment. Herein, we describe a xenograft mouse model of brain metastasis generated via tail-vein injection of an endogenously HER2-amplified cell line derived from inflammatory breast cancer (IBC), a rare and aggressive form of breast cancer. Cells were labeled with firefly luciferase and green fluorescence protein to monitor brain metastasis, and quantified metastatic burden by bioluminescence imaging, fluorescent stereomicroscopy, and histologic evaluation. Mice robustly and consistently develop brain metastases, allowing investigation of key mediators in the metastatic process and the development of preclinical testing of new treatment strategies.

We describe a xenograft mouse model of breast cancer brain metastasis generated via tail-vein injection of an endogenously HER2-amplified inflammatory breast cancer cell line.

Metastatic spread to the brain is a common and devastating manifestation of many types of cancer. In the United States alone, about 200,000 patients are ...

Mammary Epithelial and Endothelial Cell Spheroids as a Potential Functional In vitro Model for Breast Cancer Research

Breast cancer is the leading cause of mortality in women. The growth of breast cancer cells and their subsequent metastasis is a key factor for its progression. Although the mechanisms involved in promoting breast cancer growth have been intensively studied using monocultures of breast cancer cells such as MCF-7 cells, the contribution of other cell types, such as vascular and lymphatic endothelial cells that are intimately involved in tumor growth, has not been investigated in depth. Cell-cell interaction plays a key role in tumor growth and progression. Neoangiogenesis, or the development of vessels, is essential for tumor growth, whereas the lymphatic system serves as a portal for cancer cell migration and subsequent metastasis. Recent studies provide evidence that vascular and lymphatic endothelial cells can significantly influence cancer cell growth. These observations imply a need for developing in vitro models that would more realistically reflect breast cancer growth processes in vivo. Moreover, restrictions in animal research require the development of ex vivo models to elucidate better the mechanisms involved.
This article describes the development of breast cancer spheroids composed of both breast cancer cells (estrogen receptor-positive MCF-7 cells) and vascular and/or lymphatic endothelial cells. The protocol describes a detailed step-by-step approach in creating dual-cell spheroids using two different approaches, hanging drop (gold standard and cheap) and 96-well U-bottom plates (expensive). In-depth instructions are provided for how to delicately pick up the formed spheroids to monitor growth by microscopic sizing and assessing viability using dead and live cell staining. Moreover, procedures to fix the spheroids for sectioning and staining with growth-specific antibodies to differentiate growth patterns in spheroids are delineated. Additionally, details for preparing spheroids with transfected cells and methods to extract RNA for molecular analysis are provided. In conclusion, this article provides in-depth instructions for preparing multi-cell spheroids for breast cancer research.

Mammary Epithelial and Endothelial Cell Spheroids as a Potential Functional In vitro Model for Breast Cancer Research

Crosstalk between mammary epithelial cells and endothelial cells importantly contributes to breast cancer progression, tumor growth, and metastasis. In this study, spheroids have been made from breast cancer cells together with vascular and/or lymphatic endothelial cells and demonstrate their applicability as an in vitro system for breast cancer research.

Breast cancer is the leading cause of mortality in women. The growth of breast cancer cells and their subsequent metastasis is a key factor for its ...

Monitoring Breast Cancer Growth and Metastatic Colony Formation in Mice using Bioluminescence

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several animal models have been generated, including the widely used orthotopic mouse models, where cancer cells are injected into the mammary fat pad. However, these models cannot help monitor tumor growth kinetics and metastatic colonization. Cutting-edge tools to monitor cancer cells in real time in mice will significantly advance the understanding of tumor biology. 
Here, breast cancer cell lines stably expressing luciferase and green fluorescent protein (GFP) were established. Specifically, this technique contains two sequential steps initiated by measuring the luciferase activity in vitro and followed by the implantation of the cancer cells into mammary fat pads of nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. After the injection, both the tumor growth and metastatic colonization are monitored in real time by the noninvasive bioluminescence imaging system. Then, the quantification of GFP-expressing metastases in the lungs will be examined by fluorescence microscopy to validate the observed bioluminescence results. This sophisticated system combining luciferase and fluorescence-based detection tools evaluates cancer metastasis in vivo, which has great potential for use in breast cancer therapeutics and disease management.

Here, we describe a noninvasive monitoring method involving luciferase and green fluorescent protein expression in various breast cancer cell lines. This protocol provides a technique to monitor tumor formation and metastatic colonization in real time in mice.

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several ...

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

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

A Portal Vein Injection Model to Study Liver Metastasis of Breast Cancer

Flow Cytometric Detection of Newly-formed Breast Cancer Stem Cell-like Cells After Apoptosis Reversal

Modeling Breast Cancer via an Intraductal Injection of Cre-expressing Adenovirus into the Mouse Mammary Gland

Studying Triple Negative Breast Cancer Using Orthotopic Breast Cancer Model

Rat Mammary Epithelial Cell Transplantation into the Interscapular White Fat Pad

Orthotopic Transplantation of Breast Tumors as Preclinical Models for Breast Cancer

Modeling Brain Metastasis Via Tail-Vein Injection of Inflammatory Breast Cancer Cells

Mammary Epithelial and Endothelial Cell Spheroids as a Potential Functional In vitro Model for Breast Cancer Research

Monitoring Breast Cancer Growth and Metastatic Colony Formation in Mice using Bioluminescence