We thank Dr. Rosana De Lima Pagano and Ana Carolina Pinheiro Campos for technical assistance. This work was supported by grants from: FAPESP - S&#227;o Paulo Research Foundation (2016/07463-4) and Ludwig Institute for Cancer Research (LICR).

LNs were recovered from fresh carcasses of healthy adult Wistar rats sacrificed by cervical dislocation. We followed the NIH Guidelines for Pain and Distress in Laboratory Animals and all procedures were approved by the Ethics Committee and Animal Research of the Research and Education Institute of the S&#237;rio-Liban&#234;s hospital (CEUA P 2016-04).
NOTE: All fresh frozen tissues are considered biohazardous and should be handled using appropriate biosafety precautions.
<p class="jove_ti...

<ol>
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P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+significance+of+the+distribution+of+neck+node+metastasis+from+oral+carcinoma.">Prognostic significance of the distribution of neck node metastasis from oral carcinoma.</a> Head &amp; Neck. 22 (3), 207-214 (2000).</li><li>McGuire, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+factors+for+recurrence+and+survival+in+human+breast+cancer.">Prognostic factors for recurrence and survival in human breast cancer.</a> Breast Cancer Research and Treatment. 10 (1), 5-9 (1987).</li><li>Gervasi, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+significance+of+lymph+nodal+metastases+in+prostate+cancer.">Prognostic significance of lymph nodal metastases in prostate cancer.</a> The Journal of Urology. 142 (2 Pt 1), 332-336 (1989).</li><li>Naruke, T., Suemasu, K., Ishikawa, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymph+node+mapping+and+curability+at+various+levels+of+metastasis+in+resected+lung+cancer.">Lymph node mapping and curability at various levels of metastasis in resected lung cancer.</a> The Journal of Thoracic and Cardiovascular Surgery. 76 (6), 832-839 (1978).</li><li>Sasako, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=D2+lymphadenectomy+alone+or+with+para-aortic+nodal+dissection+for+gastric+cancer.">D2 lymphadenectomy alone or with para-aortic nodal dissection for gastric cancer.</a> The New England Journal of Medicine. 359 (5), 453-462 (2008).</li><li>Chang, G. 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Lymphatic system dissemination of cancer cells requires a variety of complex cell-driven events. They initiate with cell detachment from primary tumor and the remodeling of the extracellular matrix (ECM) architecture, and are supported by persistent chemotaxis and active migration through the afferent lymphatics en route to the sentinel LNs. If cancer cells adhere and survive in LNs, they can easily spread to other secondary organs. Here we describe an easy method for rapid and low-cost functional analysis of specific ad...

Cancer metastasis is the main reason for treatment failure and the dominant life-threatening aspect of cancer. As postulated 130 years ago, the metastatic spread results when an elite of disseminated tumor cells (DTCs, the &#34;seeds&#34;) acquire specific biological abilities that allow them to evade primary sites and establish malignant growth at distant sites (the &#34;soil&#34;)1. Recently, several novel concepts regarding the &#34;seed and soil&#34; relations have emerged, such as the induction of premetastatic niches (conceptualized as a &#34;fertile soil&#34; needed for &#34;seeds&#34; to thrive), self-seeding of primary tumors by DTCs, &#34;seed&#34; dormancy at secondary organs and the parallel progression model of metastasis2.
For most solid malignancies, DTCs can reside and be detected in many mesenchymal organs, such as bone marrow and lymph nodes (LNs) in patients with or without evidence of clinical metastasis. Because tumor-draining LNs are the first location of the regional spread of DTCs, LN status is an important prognostic indicator and is often associated with adjuvant therapy decisions3. For some tumor types, the correlation between LN status and worse outcomes is strong, including head and neck4,5, breast6, prostate7, lung8, gastric9, colorectal10,11 and thyroid cancers12.
LNs are small ovoid organs of the lymphatic system, that are covered with reticular cells and enclosed with lymphatic vessels. These organs are absolutely necessary for the functioning of the immune system13. LNs act as attractant platforms for immune circulating cells, bringing the lymphocytes and antigen-presenting cells together14. However, LNs also attract circulating tumor cells. Over decades, LNs were pictured as passive routes of transportation for metastatic tumor cells. However, recent studies have indicated that tumor cells may also be guided towards LNs by chemotactic (chemokines) and/or haptotactic (extracellular matrix elements) cues secreted by the lymphatic endothelium15. As examples, overexpression of the CCR7 receptor in tumor cells facilitates the guidance of metastatic melanoma cells towards tumor-draining LNs16. In addition, extracellular LN proteins provide an adhesive scaffold for the recruitment and survival of circulating tumor cells17. In fact, tumor-draining LNs provide fertile soil for the seeding of DTCs, which can be maintained in proliferative or dormant states by specific LN microenvironmental signals18. The final fate of these LN-residing DTCs is controversial; some works suggest that these cells are passive indicators of metastatic progression19, while others propose that they are more likely founders of resistance (by self-seeding primary sites) and/or act as cellular reservoirs for metastases (spreading &#34;seeds&#34; for tertiary cancer growth)20,21. Recently, using preclinical models, it has been demonstrated that a fraction of these LN-residing DTCs actively invaded blood vessels, entered into the blood circulation and colonized the lungs21.
Considering that the presence of cancer cells in LNs is a marker for cancer aggressiveness and invasiveness, in this study, we optimized a classic method developed by Brodt22 to quantitatively measure tumor cell adhesion to LNs in vitro. The use of a fluorescence-based assay allowed us to develop a low-cost, rapid, sensitive and environmentally friendly (nonradioactive) protocol for the detection of adhesive alterations between tumor cells and LN cryosections. Using the MCF-7 breast cancer cells expressing different levels of NDRG4 gene expression and rat LN frozen sections to exemplify the method, we showed that this protocol allowed a good correlation between tumor cell adhesion to LNs in vitro and LN metastasis observed in breast cancer patients24.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>15 mL Conical Tubes</td>
			<td>Corning</td>
			<td>352096</td>
			<td></td>
		</tr>
		<tr>
			<td>2-propanol</td>
			<td>Merck</td>
			<td>109634</td>
			<td></td>
		</tr>
		<tr>
			<td>Benchtop Laminar Flow</td>
			<td>Esco Cell Culture</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bin for Disc</td>
			<td>Leica</td>
			<td>14020139126</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A9647-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture flask T-25 cm2</td>
			<td>Corning</td>
			<td>430372</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat</td>
			<td>Leica</td>
			<td>CM1860 UV</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat-Brush with magnet</td>
			<td>Leica</td>
			<td>14018340426</td>
			<td></td>
		</tr>
		<tr>
			<td>DiIC18 Cell Traker Dye</td>
			<td>Molecular Probes</td>
			<td>V-22885</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Life Technologies</td>
			<td>12657-029</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>Nikon Eclipse 80</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Forma Series II CO2 incubator</td>
			<td>Thermo Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>252549</td>
			<td></td>
		</tr>
		<tr>
			<td>High Profile Disposable Razor</td>
			<td>Leica</td>
			<td>14035838926</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubation Cube (IHC)</td>
			<td>KASVI</td>
			<td>K560030</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Olympus</td>
			<td>CKX31</td>
			<td></td>
		</tr>
		<tr>
			<td>Isofluran 100 mL</td>
			<td>Crist&#225;lia</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid Bloquer Super Pap Pen</td>
			<td>Abcam, Life Science Reagents</td>
			<td>ab2601</td>
			<td></td>
		</tr>
		<tr>
			<td>Optimal Cutting Temperature &#34;OCT&#34; compound</td>
			<td>Sakura</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered Saline (PBS)</td>
			<td>Life Technologies</td>
			<td>70011-044</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-L-lysine</td>
			<td>Sigma-Aldrich</td>
			<td>P8920</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI</td>
			<td>Gibco</td>
			<td>31800-022</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes 1 mL</td>
			<td>Jet Biofil</td>
			<td>GSP010001</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes 10 mL</td>
			<td>Jet Biofil</td>
			<td>GSP010010</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes 2 mL</td>
			<td>Jet Biofil</td>
			<td>GSP010002</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes 5 mL</td>
			<td>Jet Biofil</td>
			<td>GSP010005</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes 50 mL</td>
			<td>Jet Biofil</td>
			<td>GSP010050</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettor Easypet 3</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue-Tek cryomold</td>
			<td>Sakura</td>
			<td>4557</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan Blue 0.4%</td>
			<td>Invitrogen</td>
			<td>T10282</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Instituto Adolfo Lutz</td>
			<td>ATV</td>
			<td></td>
		</tr>
	</tbody>
</table>

quantification of tumor cell adhesion in lymph node cryosections

Tumor-draining lymph nodes (LNs) are not merely filters of tumor-produced waste. They are one of the most common regional sites of provisional residence of disseminated tumor cells in patients with different types of cancer. The detection of these LN-residing tumor cells is an important biomarker associated with poor prognosis and adjuvant therapy decisions. Recent mouse models have indicated that LN-residing tumor cells could be a substantial source of malignant cells for distant metastases. The ability to quantify the adhesivity of tumor cells to LN parenchyma is a critical gauge in experimental research that focuses on the identification of genes or signaling pathways relevant for lymphatic/metastatic dissemination. Because LNs are complex 3D structures with a variety of appearances and compositions in tissue sections depending on the plane of section, their matrices are difficult to replicate experimentally in vitro in a fully controlled way. Here, we describe a simple and inexpensive method that allows the quantification of adhesive tumor cells to LN cryosections. Using serial sections of the same LN, we adapt the classic method developed by Brodt to use nonradioactive labels and directly count the number of adhering tumor cells per LN surface area. LN-adherent tumor cells are readily identified by light microscopy and confirmed by a fluorescence-based method, giving an adhesion index that reveals the cell-binding affinity to LN parenchyma, which is suggestive evidence of molecular alterations in the affinity binding of integrins to their correlate LN-ligands.

We illustrate the assay by evaluating the LN adhesive potential of red fluorescent MCF-7 breast cancer cells expressing different levels of the NDRG4 gene (referred to as NDRG4-positive and NDRG4-negative cells), a negative modulator of beta1-integrin clustering at the cell surface24, by examining the fractions of rat LN-adherent tumor cells. Examples of the raw images of this protocol are shown in Figure 2. As observed in <strong clas...

Watch this Scientific Journal Video about Quantification of Tumor Cell Adhesion in Lymph Node Cryosections at JoVE.com

Quantification of Tumor Cell Adhesion in Lymph Node Cryosections

Here, we describe a simple and inexpensive method that allows the quantification of adhesive tumor cells to lymph node (LN) cryosections. LN-adherent tumor cells are readily identified by light microscopy and confirmed by a fluorescence-based method, giving an adhesion index that reveals the tumor cell-binding affinity to LN parenchyma.

Tumor-draining lymph nodes (LNs) are not merely filters of tumor-produced waste. They are one of the most common regional sites of provisional residence ...

The most frequent sites for metastasis are the original lymph nodes. Somatids can be used to detect the adhesive affinity between tumor cells'lymph node sections in vitro. One advantage of this technique is that fresh lymph node sections provide a natural complexity of the original tissue, which wouldn't be possible to recreate using purified proteins.This method could be useful for molecular oncology studies that seek to identify genes or therapies that interfere with tumor cells'adhesion at metastatic target organs, like lymph nodes. To harvest the lymph nodes within thirty minutes of sacrifice, place the adult Wistar rat in dorsal recumbency on a clean dissection board at room temperature and spray the fur with 70%isopropyl alcohol. Using sterilized instruments, lift the abdominal skin and make a medial skin incision to expose the abdominal viscera.Extract the intestine until the thoracic and abdominal lymph nodes become visible. Using blunt-tip scissors, carefully excise the lymph nodes without injuring the underlying superior mesenteric artery, and place the lymph node into a 15 mL tube containing 5 mL of sterile PBS. When all of the lymph nodes have been harvested, place one lymph node per cryomold face down on the base of each mold and add just enough optimal cutting temperature medium to cover the tissues.After snap freezing, use a cryostat to acquire 5 to 8 micrometer thick sections at 22 degrees Celsius and collect the sections onto glass microscope slides. Good quality cryosections from consecutive slices of the same lymph node are critical for minimizing differences between slices, and facilitating consistent cell adhesion rates. For tumor cell labeling, harvest the cells of interest from an appropriately staged cell culture and re-suspend the cells at a 1 x 10 to the 6 cells per mL concentration and serum-free medium.Transfer 1 mL of cells into a new 15 mL conical tube and label the cells with 2 micrograms per mL DiI(C18)for ten minutes at 37 degrees Celsius, with gentle agitation at five minutes to avoid cell sedimentation. At the end of the incubation, pellet the cells by centrifugation and wash the labeled cells two times with 10 mL of fresh serum-free medium to remove any excess dye. After the second wash, re-suspend the cells at a 1 x 10 to the 6 cells per mL of serum-free medium, supplemented with 0.1%bovine serum albumin concentration.Proceeding of the labeled tumor cells onto the harvested lymph nodes tissue sections, gently wash the sections two times in PBS, followed by re-hydration in fresh PBS for fifteen minutes at room temperature. At the end of the incubation, block any non-specific binding with 2.5%bovine serum albumin for thirty minutes at 37 degrees Celsius, before using a cotton swab to dry the slides. Use a hydrophobic pen to draw a barrier around each section and add 100 microliters of labeled cells onto each encircled lymph node.After one to two hours at 37 degrees Celsius in a humidified chamber, remove any non-adherence cells with four gentle washes in PBS and fix the remaining adherent fluorescence cells with 3.7%formaldehyde in PBS for fifteen minutes at room temperature. For quantification of the adhesive index, use the 10x objective on a fluorescence microscope to obtain individual TIFF images of each section in the bright and red fluorescent fields. Then, name and save the images systematically before opening the images in Fiji.After setting the scale, use the polygonal tool to select the region of interest to be quantified. Select to quantify lymph node area. The data will be expressed in square millimeters.Next, select Plugins, Analyze, Cell Counter and click the photo to be quantified. Click Initialize and select Counter Type. Then, click on the cells in the photo.The lymph node adhesion index will be expressed as the number of adherent tumor cells per lymph node covered area. To initialize the next photo, open the next photo and repeat the quantification as demonstrated. As observed, the morphology of the adherent cells is rounded in shape, and the cells are heterogeneously dispersed throughout the lymph node of interest.The lymph node adhesion index is two to three fold higher in NDRG4 negative breast cancer cell lines, compared to that measured for corresponding NDRG4 positive cells. This procedure can be adapted to assist adhesion rates in other metastatic target tissues, like brain or lungs, to evaluate the secondary preferential sites of adhesion for inseminated tumor cells. Remember that both fresh and frozen tissues should be considered biohazardous and should be handled using appropriate bio-safety precautions.

quantification-of-tumor-cell-adhesion-in-lymph-node-cryosections

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JoVE Journal

Cancer Research

11.2K ビュー.  Hospital Sírio-Libanês. 転移の最も頻繁な部位は、元のリンパ節である。ソマチドは、インビトロで腫瘍細胞リンパ節間の接着親和性を検出するために使用することができる。この技術の利点の1つは、新鮮なリンパ節セクションが元の組織の自然な複雑さを提供し、精製されたタンパク質を使用して再現できないことです。この方法は、リンパ節のような転移性標的器官における腫瘍細胞...

ビデオ: Quantification of Tumor Cell Adhesion in Lymph Node Cryosections

Lung Tumor Cell Recruitment Assay

To investigate the molecular mechanisms governing tumor metastasis, various assays using the mouse as a model animal have been proposed. Here, we demonstrate a simple assay to evaluate tumor cell extravasation or micrometastasis. In this assay, tumor cells were injected through the tail vein, and after a short period, the lungs were dissected and digested to count the accumulated labeled tumor cells. This assay skips the initial step of primary tumor invasion into the blood vessel and facilitates the study of events in the distant organ where tumor metastasis occurs. The number of cells injected into the blood vessel can be optimized to observe a limited number of metastases. It has been reported that stromal cells in the distant organ contribute to metastasis. Thus, this assay could be a useful tool to explore potential therapeutic drugs or devices for prevention of tumor metastasis.

This manuscript describes a method to quantify tumor cell accumulation in the lungs in an animal model of tumor metastasis.

To investigate the molecular mechanisms governing tumor metastasis, various assays using the mouse as a model animal have been proposed. Here, we ...

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the context of a whole organism. Sophisticated techniques to generate genetic mosaics facilitate induction of visually marked, genetically defined clones surrounded by normal tissue. The clones can be analyzed through diverse molecular, cellular and omics approaches. This study describes how to generate fluorescently labeled clonal tumors of varying malignancy in the eye/antennal imaginal discs (EAD) of Drosophila larvae using the Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. It describes procedures how to recover the mosaic EAD and brain from the larvae and how to process them for simultaneous imaging of fluorescent transgenic reporters and antibody staining. To facilitate molecular characterization of the mosaic tissue, we describe a protocol for isolation of total RNA from the EAD. The dissection procedure is suitable to recover EAD and brains from any larval stage. The fixation and staining protocol for imaginal discs works with a number of transgenic reporters and antibodies that recognize Drosophila proteins. The protocol for RNA isolation can be applied to various larval organs, whole larvae, and adult flies. Total RNA can be used for profiling of gene expression changes using candidate or genome-wide approaches. Finally, we detail a method for quantifying invasiveness of the clonal tumors. Although this method has limited use, its underlying concept is broadly applicable to other quantitative studies where cognitive bias must be avoided.

The Drosophila Imaginal Disc Tumor Model: Visualization and Quantification of Gene Expression and Tumor Invasiveness Using Genetic Mosaics

This protocol demonstrates how to generate fluorescently marked, genetically defined clonal tumors in the Drosophila eye/antennal imaginal discs (EAD). It describes how to dissect the EAD and brain from the third instar larvae and how to process them to visualize and quantify gene expression changes and tumor invasiveness.

Drosophila melanogaster has emerged as a powerful experimental system for functional and mechanistic studies of tumor development and progression in the ...

Tumor Engraftment in a Xenograft Mouse Model of Human Mantle Cell Lymphoma

B lymphocytes are key players in immune cell circulation and they mainly home to and reside in lymphoid organs. While normal B cells only proliferate when stimulated by T lymphocytes, oncogenic B cells survive and expand autonomously in undefined organ niches. Mantle cell lymphoma (MCL) is one such B cell disorder, where the median survival rate of patients is 4 - 5 years. This calls for the need of effective mechanisms by which the homing and engraftment of these cells are blocked in order to increase the survival and longevity of patients. Therefore, the effort to develop a xenograft mouse model to study the efficacy of MCL therapeutics by blocking the homing mechanism in vivo is of utmost importance. Development of animal recipients for human cell xenotransplantation to test early stage drugs have long been pursued, as relevant preclinical mouse models are crucial to screen new therapeutic agents. This animal model is developed to avoid human graft rejection and to establish a model for human diseases, and it may be an extremely useful tool to study disease progression of different lymphoma types and to perform preclinical testing of candidate drugs for hematologic malignancies, like MCL. We established a xenograft mouse model that will serve as an excellent resource to study and develop novel therapeutic approaches for MCL.

Mantle cell lymphoma (MCL) is a difficult to treat B cell disorder and it is equally difficult to establish a xenograft mouse model of primary MCL to study and develop therapeutics. Here, we describe the successful establishment of MCL xenografts in mice to help understand its underlying biology.

B lymphocytes are key players in immune cell circulation and they mainly home to and reside in lymphoid organs. While normal B cells only proliferate when ...

Characterization of Cell Membrane Extensions and Studying Their Roles in Cancer Cell Adhesion Dynamics

The cell membrane&#39;s extension repertoire modulates various malignant behaviors of cancer cells, including their adhesive and migratory potentials. The ability to accurately classify and quantify cell extensions and measure the effect on a cell&#39;s adhesive capacity is critical to determining how cell-signaling events impact cancer cell behavior and aggressiveness. Here, we describe the in vitro design and use of a cell extension quantification method in conjunction with an adhesion capacity assay in an established in vitro model for adrenocortical carcinoma (ACC). Specifically, we test the effects of DKK3, a putative tumor suppressor and a pro-differentiation factor, on the membrane extension phenotype of the ACC cell line, SW-13. We propose these assays to provide relatively simple, reliable, and easily interpretable metrics to measures these characteristics under various experimental conditions.

This study demonstrates the utility and ease of quantitative cell membrane extension measurement and its correlation to adhesive capacity of cells. As a representative example, we show here that Dickkopf-related protein 3 (DKK3) promotes increased lobopodia formation and cell adhesiveness in adrenocortical carcinoma cells in vitro.

The cell membrane&#39;s extension repertoire modulates various malignant behaviors of cancer cells, including their adhesive and migratory potentials. The ...

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment

This protocol demonstrates the capability of low-field electron paramagnetic resonance (EPR)-based techniques in combination with functional paramagnetic probes to provide quantitative information on the chemical tumor microenvironment (TME), including pO2, pH, redox status, concentrations of interstitial inorganic phosphate (Pi), and intracellular glutathione (GSH). In particular, an application of a recently developed soluble multifunctional trityl probe provides unsurpassed opportunity for in vivo concurrent measurements of pH, pO2 and Pi in Extracellular space (HOPE probe). The measurements of three parameters using a single probe allow for their correlation analyses independent of probe distribution and time of the measurements.

In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment

Low-field (L-band, 1.2 GHz) electron paramagnetic resonance using soluble nitroxyl and trityl probes is demonstrated for assessment of physiologically important parameters in the tumor microenvironment in mouse models of breast cancer.

This protocol demonstrates the capability of low-field electron paramagnetic resonance (EPR)-based techniques in combination with functional paramagnetic ...

Digital Polymerase Chain Reaction Assay for the Genetic Variation in a Sporadic Familial Adenomatous Polyposis Patient Using the Chip-in-a-tube Format

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as tumors. Because digital polymerase chain reactions (PCR) enable the precise quantification of DNA copy number variants, they are becoming an essential tool for detecting rare genetic variations, such as drug-resistant mutations. It is expected that molecular diagnoses using digital PCR (dPCR) will be available in clinical practice in the near future; thus, how to efficiently conduct dPCR with human genetic material is a hot topic. Here, we introduce a method to detect Adenomatous polyposis coli (APC) somatic mosaicism using dPCR with the chip-in-a-tube format, which allows eight dPCR reactions to be simultaneously conducted. Care should be taken when filling and sealing the reaction mixture on the chips. This article demonstrates how to avoid the over- and underestimation of positive partitions. Furthermore, we present a simple procedure for collecting the dPCR product from the partitions on the chips, which can then be used to confirm the specific amplification. We hope that this methods report will help promote the dPCR with the chip-in-a-tube method in genetic research.

Digital polymerase chain reaction (PCR) is a useful tool for the high-sensitivity detection of single nucleotide variants and DNA copy number variants. Here, we demonstrate key considerations for measuring rare variants in the human genome using digital PCR with the chip-in-a-tube format.

The quantitative analysis of human genetic variation is crucial for understanding the molecular characteristics of serious medical conditions, such as ...

In Vitro Tumor Cell Rechallenge For Predictive Evaluation of Chimeric Antigen Receptor T Cell Antitumor Function

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and manufacturing optimizations. One challenge for these development efforts, however, has been the establishment of in vitro assays that can robustly inform selection of the optimal CAR T cell products for in vivo therapeutic success. Standard in vitro tumor-lysis assays often fail to reflect the true antitumor potential of the CAR T cells due to the relatively short co-culture time and high T cell to tumor ratio. Here, we describe an in vitro co-culture method to evaluate CAR T cell recursive killing potential at high tumor cell loads. In this assay, long-term cytotoxic function and proliferative capacity of CAR T cells is examined in vitro over 7 days with additional tumor targets administered to the co-culture every other day. This assay can be coupled with profiling T cell activation, exhaustion and memory phenotypes. Using this assay, we have successfully distinguished the functional and phenotypic differences between CD4+ and CD8+ CAR T cells against glioblastoma (GBM) cells, reflecting their differential in vivo antitumor activity in orthotopic xenograft models. This method provides a facile approach to assess CAR T cell potency and to elucidate the functional variations across different CAR T cell products.

Here, we describe an in vitro co-culture method to recursively challenge tumor-targeted T cells, which allows for phenotypic and functional analysis of antitumor T cell activity.

The field of chimeric antigen receptor (CAR) T cell therapy is rapidly advancing with improvements in CAR design, gene-engineering approaches and ...

Analysis of Side Population in Solid Tumor Cell Lines

Cancer stem cells (CSCs) are an important cause of tumor growth, metastasis, and recurrence. Isolation and identification of CSCs are of great significance for tumor research. Currently, several techniques are used for the identification and purification of CSCs from tumor tissues and tumor cell lines. Separation and analysis of side population (SP) cells are two of the commonly used methods. The methods rely on the ability of CSCs to rapidly expel fluorescent dyes, such as Hoechst 33342. The efflux of the dye is associated with the ATP-binding cassette (ABC) transporters and can be inhibited by ABC transporter inhibitors. Methods for staining cultured tumor cells with Hoechst 33342 and analyzing the proportion of their SP cells by flow cytometry are described. This assay is convenient, fast, and cost-effective. Data generated in this assay can contribute to a better understanding of the effect of genes or other extracellular and intracellular signals on the stemness properties of tumor cells.

A convenient, fast, and cost-effective method to measure the proportion of side population cells in solid tumor cell lines is presented.

Cancer stem cells (CSCs) are an important cause of tumor growth, metastasis, and recurrence. Isolation and identification of CSCs are of great ...

Analysis of Lymph Node Volume by Ultra-High-Frequency Ultrasound Imaging in the Braf/Pten Genetically Engineered Mouse Model of Melanoma

Tyr::CreER+,BrafCA/+,Ptenlox/lox&#160;genetically engineered mice (Braf/Pten mice) are widely used as an in vivo model of metastatic melanoma. Once a primary tumor has been induced by tamoxifen treatment, an increase in metastatic burden is observed within 4-6 weeks after induction. This paper shows how Ultra-High-Frequency UltraSound (UHFUS) imaging can be exploited to monitor the increase in metastatic involvement of the inguinal lymph nodes by measuring the increase in their volume.
The UHFUS system is used to scan anesthetized mice with a UHFUS linear probe (22-55 MHz, axial resolution 40 &#181;m). B-mode images from the inguinal lymph nodes (both left and right sides) are acquired in a short-axis view, positioning the animals in dorsal recumbency. Ultrasound records are acquired using a 44 &#181;m step size on a motorized mechanical arm. Afterward, two-dimensional (2D) B-mode acquisitions are imported into the software platform for ultrasound image post-processing, and inguinal lymph nodes are identified and segmented semi-automatically in the acquired cross-sectional 2D images. Finally, a total reconstruction of the three-dimensional (3D) volume is automatically obtained along with the rendering of the lymph node volume, which is also expressed as an absolute measurement.
This non-invasive in vivo technique is very well tolerated and allows the scheduling of multiple imaging sessions on the same experimental animal over 2 weeks. It is, therefore, ideal to assess the impact of pharmacological treatment on metastatic disease.

Melanoma is a very aggressive disease that quickly spreads to other organs. This protocol describes the application of ultra-high-frequency ultrasound imaging, coupled with 3D rendering, to monitor the volume of the inguinal lymph nodes in the Braf/Pten mouse model of metastatic melanoma.

Tyr::CreER+,BrafCA/+,Ptenlox/lox&#160;genetically engineered mice (Braf/Pten mice) are widely used as an in vivo model of metastatic melanoma. Once a ...

Sentinel Lymph Node Mapping and Biopsy for Endometrial Cancer at Early Stage with Laparoscopy

Sentinel lymph node (SLN) mapping and biopsy is a promising technique for visualizing and evaluating lymph node status in cancer. This approach has been recommended for low-risk endometrial cancer (EC) patients by authoritative international guidelines, but it has not been performed broadly in China and worldwide. This work aims to describe detailed SLN mapping and biopsy procedures to promote the clinical application. SLN mapping and postoperative pathologic ultrastaging were conducted in a patient with low-risk EC using indocyanine green (ICG) dye to track the SLNs under laparoscopy and resecting them completely for ultrastaging. In conclusion, this protocol describes details of ICG injection, and SLN mapping and biopsy in EC patients based on the experiences gained during clinical practice.

This protocol describes the identification and resection of sentinel lymph nodes to make the operation as easy and minimally invasive as possible.

Sentinel lymph node (SLN) mapping and biopsy is a promising technique for visualizing and evaluating lymph node status in cancer. This approach has been ...