Name: extended time-lapse intravital imaging of real-time multicellular dynamics in the tumor microenvironment
Uploaded: 2016-06-12T14:00:00
Description: Watch this Scientific Journal Video about Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment at JoVE.com

This research was supported by the Department of Defense Breast Cancer Research Program under award number (A.S.H, W81XWH-13-1-0010), NIH CA100324, &#160;PPG CA100324,&#160;and the Integrated Imaging Program.

All procedures described must be performed in accordance with guidelines and regulations for the use of vertebrate animals, including prior approval by the Albert Einstein College of Medicine Institutional Animal Care and Use Committee.
1. Generating Fluorescently Labeled Tumors and Tumor-associated Macrophages
<ol>
	<li>Generate fluorescently labeled tumor cells by crossing the spontaneous, autochthonous, genetically engineered mouse mammary cancer model where the mouse mammary tumor virus long terminal repeat ...

<ol>
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Cellular interactions that occur spontaneously in the tumor microenvironment can lead to changes in tumor cell motility and intravasation. High-resolution intravital imaging of live tumor tissue permits the visualization of multi-cellular dynamics that can be highly transient10,13,24. End-point in vivo assays or time-lapse images acquired with discrete time points can provide essential information on molecular mechanisms of processes in the tumor microenvironment. Intravital imaging studies have been ...

Dissemination of tumor cells from the primary mammary tumor has been shown to involve not only tumor cells, but host stromal cells including macrophages and endothelial cells. Furthermore, tumor vasculature is abnormal with increased permeability1. Thus, determining how tumor cells, macrophages and endothelial cells interact to mediate vascular permeability and tumor cell intravasation in the primary tumor microenvironment is important for understanding metastasis. Understanding the kinetics of vascular permeability, tumor cell intravasation and the underlying signaling mechanism of multicellular interactions in the tumor microenvironment can provide crucial information in the development and administration of anti-cancer therapies.
The primary means of studying tumor vascular permeability in vivo has been the measurement of extravascular dyes such as Evans blue2, high molecular weight dextrans (155 kDa)3 and fluorophore or radiotracer-conjugated proteins (including albumin)4 at fixed time points after injection of the dye. Advancements in microscopy, animal models and fluorescent dyes have enabled the visualization of cellular processes and vascular permeability in live animals through intravital microscopy5.
Live animal imaging with the acquisition of static images, or short time-lapse sequences over several time points does not allow for the complete understanding of dynamic events in the tumor microenvironment6,7. Indeed, static image acquisition over the course of 24 hr demonstrated that tumor vasculature is leaky, however the dynamics of vascular permeability was not observed6. Thus, extended continuous time-lapse imaging up to 12 hours captures the kinetics of dynamic events in the tumor microenvironment.
This protocol describes the use of extended time-lapse multiphoton intravital microscopy to study dynamic multicellular events in the tumor microenvironment. Multiple cell types in the tumor microenvironment are labeled with injectable dyes or by using transgenic animals expressing fluorescent proteins. Using a tail vein catheter vascular dyes or proteins can be injected after the start of imaging to acquire kinetic data of multicellular events in the tumor microenvironment. For live cell imaging the mammary tumor is exposed through the surgical preparation of a skin flap. Images are acquired for up to 12 hours using a multiphoton microscope equipped with multiple photomultiplier tubes (PMT) detectors8. By using appropriate filters, a subtraction algorithm enables 4 PMT detectors to acquire 5 fluorescent signals in the tumor microenvironment simultaneously9. High-resolution multiphoton intravital microscopy captures single cell resolution imaging of tumor-stroma interactions in the tumor microenvironment, leading to a better understanding of vascular permeability and tumor cell intravasation10-13. Specifically, extended intravital imaging revealed highly localized, transient vascular permeability events that occur selectively at sites of interaction between a tumor cell, a macrophage and an endothelial cell (defined as the Tumor MicroEnvironment of Metastasis, TMEM14)13. Furthermore, tumor cell intravasation occurs only at TMEM and is spatially and temporally correlated with vascular permeability13. Single cell resolution of the dynamics of these events was made possible through the use of extended time-lapse multiphoton microscopy of fluorescently labeled cells in the tumor microenvironment.

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			<td height="63" style="height:63px;width:248px;">155 kDa dextran-tetramethylrhodamine isothiocyanate</td>
			<td style="width:95px;">Sigma Aldrich</td>
			<td style="width:128px;">T1287</td>
			<td style="width:167px;">reconstitute at 20 mg/mL in 1 X PBS</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">70 kDa dextran-Texas Red</td>
			<td style="width:95px;">Life Technologies</td>
			<td style="width:128px;">D-1830</td>
			<td>reconstitute at 10 mg/mL in 1 X PBS</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">10 kDa dextran-fluorescein isothyocyanate</td>
			<td style="width:95px;">Sigma Aldrich</td>
			<td style="width:128px;">FD10S</td>
			<td>reconstitute at 20 mg/mL in 1 X PBS</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">Qdot 705 ITK Amino (PEG) Quantum Dots</td>
			<td style="width:95px;">Life Technologies</td>
			<td style="width:128px;">Q21561MP</td>
			<td>Dilute 25 uL in 175 uL of 1 X PBS for injection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">MMTV-PyMT mice</td>
			<td style="width:95px;">Jackson Laboratory</td>
			<td align="right" style="width:128px;">2374</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">Csf1r-ECFP mice (Csf1r-Gal4/VP16,UAS-ECFP)</td>
			<td style="width:95px;">Jackson Laboratory</td>
			<td align="right" style="width:128px;">26051</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">Csf1r-EGFP mice</td>
			<td style="width:95px;">Jackson Laboratory</td>
			<td align="right" style="width:128px;">18549</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">1 x PBS</td>
			<td style="width:95px;">Life Technologies</td>
			<td style="width:128px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:248px;">Isoethesia (isoflurane)</td>
			<td style="width:95px;">Henry Schein Animal Health</td>
			<td align="right" style="width:128px;">50033</td>
			<td>250 mL</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">Oxygen</td>
			<td style="width:95px;">AirTech</td>
			<td style="width:128px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">1 mL syringe, tuberculin slip tip</td>
			<td style="width:95px;">BD</td>
			<td align="right" style="width:128px;">309659</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">30G x 1 (0.3 mm X 25 mm) needle</td>
			<td style="width:95px;">BD</td>
			<td align="right" style="width:128px;">305128</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:248px;">Polyethylene micro medical tubing&#160;</td>
			<td style="width:95px;">Scientific Commodities Inc</td>
			<td style="width:128px;">BB31695-PE/1</td>
			<td>0.28 mm I.D. X 0.64 mm O.D.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">Microscope coverglass</td>
			<td style="width:95px;">Corning</td>
			<td style="width:128px;">2980-225</td>
			<td>thickness 1.5, 22 X 50 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">MouseOx oximeter, software and sensors</td>
			<td style="width:95px;">STARR Life Sciences</td>
			<td style="width:128px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">Laboratory tape</td>
			<td style="width:95px;">Fisher Scientific</td>
			<td style="width:128px;">159015R</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">soft rubber pad</td>
			<td style="width:95px;">McMaster-Carr</td>
			<td>8514K62</td>
			<td>Ultra-Soft Polyurethane Film, 3/16&#8221; Thick, 12&#34; x 12&#34;, 40 Oo Durometer, Plain Back</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">hard rubber pad</td>
			<td style="width:95px;">McMaster-Carr</td>
			<td>8568K615</td>
			<td>High-Strength Neoprene Rubber Sheet 1/4&#34; Thick, 12&#34; X 12&#34;, 50A Durometer,</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:248px;">Microscope</td>
			<td style="width:95px;">Olympus</td>
			<td style="width:128px;"></td>
			<td>The microscope is a custom built two laser multiphoton microscope based on an Olympus IX-71 stand utilizing a 20x 1.05NA objective lens.&#160;</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:248px;">7-Punch set</td>
			<td style="width:95px;">McMaster-Carr</td>
			<td style="width:128px;">3429A12</td>
			<td>, 1/4&#34; to 1&#34; Hole Diameter, for Hammer-Driven Hole Punch,&#160;</td>
		</tr>
	</tbody>
</table>

extended time-lapse intravital imaging of real-time multicellular dynamics in the tumor microenvironment

In the tumor microenvironment, host stromal cells interact with tumor cells to promote tumor progression, angiogenesis, tumor cell dissemination and metastasis. Multicellular interactions in the tumor microenvironment can lead to transient events including directional tumor cell motility and vascular permeability. Quantification of tumor vascular permeability has frequently used end-point experiments to measure extravasation of vascular dyes. However, due to the transient nature of multicellular interactions and vascular permeability, the kinetics of these dynamic events cannot be discerned. By labeling cells and vasculature with injectable dyes or fluorescent proteins, high-resolution time-lapse intravital microscopy has allowed the direct, real-time visualization of transient events in the tumor microenvironment. Here we describe a method for using multiphoton microscopy to perform extended intravital imaging in live mice to directly visualize multicellular dynamics in the tumor microenvironment. This method details cellular labeling strategies, the surgical preparation of a mammary skin flap, the administration of injectable dyes or proteins by tail vein catheter and the acquisition of time-lapse images. The time-lapse sequences obtained from this method facilitate the visualization and quantitation of the kinetics of cellular events of motility and vascular permeability in the tumor microenvironment.

Extended time-lapse intravital microscopy enables single cell resolution imaging of multicellular processes in the tumor microenvironment. By fluorescently labeling tumor cells, macrophages, the vascular space, and visualizing the collagen fiber network using the second harmonic generation signal, multiple compartments in the tumor microenvironment are simultaneously tracked during imaging. Tumor cells labeled with fluorescent proteins can be generated in transgenic mice as has been done ...

Watch this Scientific Journal Video about Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment at JoVE.com

Extended Time-lapse Intravital Imaging of Real-time Multicellular Dynamics in the Tumor Microenvironment

This protocol describes the use of multiphoton microscopy to perform extended time-lapse imaging of multicellular interactions in real time, in vivo at single cell resolution.

In the tumor microenvironment, host stromal cells interact with tumor cells to promote tumor progression, angiogenesis, tumor cell dissemination and ...

The overall goal of this procedure is to visualize the dynamic events within the tumor microenvironment via high resolution, intravital multiphoton mircrospy. This method can help answer key questions about the tumor microenvironment such as which dynamic events are involved in vascular permeability and multicellular interactions. The main advantage of this technique is that the kinetics of the events in the tumor microenvironment can be observed and measured.Before beginning the procedure, turn on all of the microscope and laser components, including the two photon lasers and the detectors. And set the heating box to 30 degree celsius to prewarm the stage. Wipe the microscope stage and stage insert with 70%ethanol.When the stage is dry, place a large drop of water on the 25 x 1.05 NA microscope objective to maintain optical contact with the cover glass and place a number 1.5 thickness cover glass over the insert imaging port. Then, cut a 30 centimeter piece of polyethylene tubing. Place the rubber pad on top of the cover glass.Using forceps, break a 31 gauge needle off of its plastic fitting and insert the blunted end of the needle hub into the tubing. Insert and attached a 31 gauge needle into the other end of the PE tubing. Then, fill a one cc syringe with sterile PBS and attach the syringe to the 31 gauge needle.Use the PBS to flush all of the air out of the tubing and needle. Then, the one one cc syringe with 200 microliters of the appropriate vascular label and another with the appropriate injectable protein. Before beginning the surgery, confirm the proper anesthesia with a lack of response to toe pinch and apply eye ointments to the anesthetized mouse.Next, place the animal on a surgical platform under a heat lamp to increase the tail circulation. After two minutes, sterilize the tail with 70%ethanol and insert the tip of the 31 gauge catheter, two to three millimeters in to the lateral tail vein. Then, place a one centimeter length of lab tape onto the catheter to hold the needle parallel to the vein along the length of the tail.When the catheter has been secured, swab the ventral and tumor surfaces with 70%ethanol. The, lift the skin over the abdomen and use sterile scissors to make an approximately one centimeter subcutaneous incision along the ventral midline of the abdomen, taking care to avoid puncturing the peritoneum. Gently cut the connective tissue attaching the mammary gland and tumor away from the peritoneum to expose the tumor.Then, using the scissors and forceps, gently remove the fascia and fat from the exposed surface of the tumor. When the tumor has been exposed, transfer the mouse to the prewarmed imaging stage. Use lab tapes to secure the cover glass, then place the tumor in the hole of a rubber pad covering the cover slip over the microscope objective.When the animal is in position, fill the rubber pad chamber with PBS to keep the tissue hydrated and to maintain optical contact with the cover slip. Place a pulse oximeter probe collar sensor around the neck to monitor the animal's vital signs and place the heating box over the animal. Then, use the microscope IPs to focus on the fluorescent tumor cells on the surface of the tumor and located area with flowing blood vessels.Once a region of interest has been selected, switch the microscope to multiphoton imaging mode and use the focus adjuster to move the objective to the desired start location. Then, click on the Z position top button to set the upper limit of the z series and visualize the collagen fiber network at the surface of the tumor in the second harmonic generation channel. Then move the objective to the desired imaging depth and click the z position bottom button to set the lower limit of the z series.Next, enter the desired value into the step size fields. Then, switch to the Time Lapse Panel and enter the appropriate lapse time. Once the imaging parameters had been determined, replaced the syringe attached to the catheter with a syringe of vascular labeling dye and slowly administer a maximum of 200 microliters of the dye solution, taking care that the solution enters the vein.After the injection, return the PBS syringe to the catheter and begin the z step time lapse imaging. When all of the images have been obtained, replace the syringe of PBS with the syringe containing the injectable protein, taking care not to introduce any bubbles into the line. Then slowly inject the protein suspension into the mouse and replace the syringe with a syringe containing PBS.Macrophages can be tracked with fluorescently labeled 70 kilodalton and dextran which acummulate in the phagocytic microphages. Dual labeling the tumor cells and the microphages allows the direct interaction with these two cell types to be visualize in real time. To visualize changes in the tumor vascular permeability, quantum dots can also be used to label the vascular space.As they are large enough that they do not readily diffuse through the interarterial spaces. Continuous high resolution imaging facilitates the capture of the vascular permeability events and the quantification of the kinetics of the dextran extravasation and clearance. In this example field of view, the peak of the vacscular di-extravasation is observed between 29 and 34 minutes as evidenced by the extra vascular TMR signal.Injecting additional vascular dyes or proteins to induce vascular permeability can provide insight into the signaling events regulating vascular permeability. Indeed, within the first few seconds of injection, 10 kilodaltons of dextran FITC can be observed extravasating from the vasculature, while the 155 kilodalton in dextran TMR remains confined to the vascular space. Once mastered, this technique can be completed in one hour if it is performed properly.While attempting this procedure, it's important to remember to remove the connective tissue gently without damaging the surface of the tumor and to keep the tumor surface hydrated. Following this procedure of cellular dynamics such tumor cell migration can be visualized to answer additional questions about the directionality of tumor cell migration and intravasation. After watching this video, you should have a good understanding of how to visualize dynamic celluluar events in a tumor microenvironment by intervital multiphoton microscopy.

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Research

JoVE Journal

Medicine

Multispectral Real-time Fluorescence Imaging for Intraoperative Detection of the Sentinel Lymph Node in Gynecologic Oncology

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical excision of the tumor with a full lymphadenectomy in the drainage area of the tumor. However, removal of lymph nodes is associated with increased morbidity due to infection, wound breakdown and lymphedema.4,5 As an alternative, the sentinel lymph node procedure (SLN) was developed several decades ago to detect the first draining lymph node from the tumor.6 In case of lymphogenic dissemination, the SLN is the first lymph node that is affected (Figure 1). Hence, if the SLN does not contain metastases, downstream lymph nodes will also be free from tumor metastases and need not to be removed. The SLN procedure is part of the treatment for many tumor types, like breast cancer and melanoma, but also for cancer of the vulva and cervix.7 The current standard methodology for SLN-detection is by peritumoral injection of radiocolloid one day prior to surgery, and a colored dye intraoperatively. Disadvantages of the procedure in cervical and vulvar cancer are multiple injections in the genital area, leading to increased psychological distress for the patient, and the use of radioactive colloid.
Multispectral fluorescence imaging is an emerging imaging modality that can be applied intraoperatively without the need for injection of radiocolloid. For intraoperative fluorescence imaging, two components are needed: a fluorescent agent and a quantitative optical system for intraoperative imaging. As a fluorophore we have used indocyanine green (ICG). ICG has been used for many decades to assess cardiac function, cerebral perfusion and liver perfusion.8 It is an inert drug with a safe pharmaco-biological profile. When excited at around 750 nm, it emits light in the near-infrared spectrum around 800 nm. A custom-made multispectral fluorescence imaging camera system was used.9.
The aim of this video article is to demonstrate the detection of the SLN using intraoperative fluorescence imaging in patients with cervical and vulvar cancer. Fluorescence imaging is used in conjunction with the standard procedure, consisting of radiocolloid and a blue dye. In the future, intraoperative fluorescence imaging might replace the current method and is also easily transferable to other indications like breast cancer and melanoma.

Fluorescence imaging is a promising innovative modality for image-guided surgery in surgical oncology. In this video we describe the technical procedure for detection of the sentinel lymph node using fluorescence imaging as showcased in gynecologic oncologicy. A multispectral fluorescence camera system, together with the fluorescent agent indocyanine green, is applied.

The prognosis in virtually all solid tumors depends on the presence or absence of lymph node metastases.1-3 Surgical treatment most often combines radical ...

Evaluation of Nanoparticle Uptake in Tumors in Real Time Using Intravital Imaging

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle uptake in tumors at the microscopic level1,2,3, highlighting the utility of a suitable xenograft model in which to perform detailed uptake analyses. Here, we use high-resolution intravital imaging to evaluate nanoparticle uptake in human tumor xenografts in a modified, shell-less chicken embryo model. The chicken embryo model is particularly well-suited for these in vivo analyses because it supports the growth of human tumors, is relatively inexpensive and does not require anesthetization or surgery 4,5. Tumor cells form fully vascularized xenografts within 7 days when implanted into the chorioallantoic membrane (CAM) 6. The resulting tumors are visualized by non-invasive real-time, high-resolution imaging that can be maintained for up to 72 hours with little impact on either the host or tumor systems. Nanoparticles with a wide range of sizes and formulations administered distal to the tumor can be visualized and quantified as they flow through the bloodstream, extravasate from leaky tumor vasculature, and accumulate at the tumor site. We describe here the analysis of nanoparticles derived from Cowpea mosaic virus (CPMV) decorated with near-infrared fluorescent dyes and/or polyethylene glycol polymers (PEG) 7, 8, 9,10,11. Upon intravenous administration, these viral nanoparticles are rapidly internalized by endothelial cells, resulting in global labeling of the vasculature both outside and within the tumor7,12. PEGylation of the viral nanoparticles increases their plasma half-life, extends their time in the circulation, and ultimately enhances their accumulation in tumors via the enhanced permeability and retention (EPR) effect 7, 10,11. The rate and extent of accumulation of nanoparticles in a tumor is measured over time using image analysis software. This technique provides a method to both visualize and quantify nanoparticle dynamics in human tumors.

We present a novel approach to quantify nanoparticle localization in the vasculature of human xenografted tumors using dynamic, real-time intravital imaging in an avian embryo model.

Current technologies for tumor imaging, such as ultrasound, MRI, PET and CT, are unable to yield high-resolution images for the assessment of nanoparticle ...

Real-time Digital Imaging of Leukocyte-endothelial Interaction in Ischemia-reperfusion Injury (IRI) of the Rat Cremaster Muscle

Ischemia-reperfusion injury (IRI) has been implicated in a large array of pathological conditions such as cerebral stroke, myocardial infarction, intestinal ischemia as well as following transplant and cardiovascular surgery.1 Reperfusion of previously ischemic tissue, while essential for the prevention of irreversible tissue injury, elicits excessive inflammation of the affected tissue. Adjacent to the production of reactive oxygen species, activation of the complement system and increased microvascular permeability, the activation of leukocytes is one of the principle actors in the pathological cascade of inflammatory tissue damage during reperfusion.2, 3 Leukocyte activation is a multistep process consisting of rolling, firm adhesion and transmigration and is mediated by a complex interaction between adhesion molecules in response to chemoattractants such as complement factors, chemokines, or platelet-activating factor.4
While leukocyte rolling in postcapillary venules is predominantly mediated by the interaction of selectins5 with their counter ligands, firm adhesion of leukocytes to the endothelium is selectin-controlled via binding to intercellular adhesion molecules (ICAM) and vascular cellular adhesion molecules (VCAM).6, 7 
Gold standard for the in vivo observation of leukocyte-endothelial interaction is the technique of intravital microscopy, first described in 1968.8
Though various models of IRI (ischemia-reperfusion injury) have been described for various organs, 9-12 only few are suitable for direct visualization of leukocyte recruitment in the microvascular bed on a high level of image quality.8 
We here promote the digital intravital epifluorescence microscopy of the postcapillary venule in the cremasteric microcirculation of the rat 13 as a convenient method to qualitatively and quantitatively analyze leukocyte recruitment for IRI-research in striated muscle tissue and provide a detailed manual for accomplishing the technique. We further illustrate common pitfalls and provide useful tips which should enable the reader to truly appreciate, and safely perform the method.
In a step by step protocol we depict how to get started with respiration controlled anesthesia under sufficient monitoring to keep the animal firmly anesthetized for longer periods of time. We then describe the cremasteric preparation as a thin flat sheet for outstanding optical resolution and provide a protocol for leukocyte imaging in IRI that has been well established in our laboratories.

Real-time Digital Imaging of Leukocyte-endothelial Interaction in Ischemia-reperfusion Injury IRI of the Rat Cremaster Muscle

Digital intravital epifluorescence microscopy of postcapillary venules in the cremasteric microcirculation is a convenient method to gain insights into leukocyte-endothelial interaction in vivo in ischemia-reperfusion injury (IRI) of striated muscle tissue. We here provide a detailed protocol to safely perform the technique and discuss its applications and limitations.

Ischemia-reperfusion injury (IRI) has been implicated in a large array of pathological conditions such as cerebral stroke, myocardial infarction, ...

Live Imaging of Drug Responses in the Tumor Microenvironment in Mouse Models of Breast Cancer

The tumor microenvironment plays a pivotal role in tumor initiation, progression, metastasis, and the response to anti-cancer therapies. Three-dimensional co-culture systems are frequently used to explicate tumor-stroma interactions, including their role in drug responses. However, many of the interactions that occur in vivo in the intact microenvironment cannot be completely replicated in these in vitro settings. Thus, direct visualization of these processes in real-time has become an important tool in understanding tumor responses to therapies and identifying the interactions between cancer cells and the stroma that can influence these responses. Here we provide a method for using spinning disk confocal microscopy of live, anesthetized mice to directly observe drug distribution, cancer cell responses and changes in tumor-stroma interactions following administration of systemic therapy in breast cancer models. We describe procedures for labeling different tumor components, treatment of animals for observing therapeutic responses, and the surgical procedure for exposing tumor tissues for imaging up to 40 hours. The results obtained from this protocol are time-lapse movies, in which such processes as drug infiltration, cancer cell death and stromal cell migration can be evaluated using image analysis software.

We describe a method for imaging response to anti-cancer treatment in vivo and at single cell resolution.

The tumor microenvironment plays a pivotal role in tumor initiation, progression, metastasis, and the response to anti-cancer therapies. Three-dimensional ...

Time-lapse Imaging of Primary Preneoplastic Mammary Epithelial Cells Derived from Genetically Engineered Mouse Models of Breast Cancer

Time-lapse imaging can be used to compare behavior of cultured primary preneoplastic mammary epithelial cells derived from different genetically engineered mouse models of breast cancer. For example, time between cell divisions (cell lifetimes), apoptotic cell numbers, evolution of morphological changes, and mechanism of colony formation can be quantified and compared in cells carrying specific genetic lesions. Primary mammary epithelial cell cultures are generated from mammary glands without palpable tumor. Glands are carefully resected with clear separation from adjacent muscle, lymph nodes are removed, and single-cell suspensions of enriched mammary epithelial cells are generated by mincing mammary tissue followed by enzymatic dissociation and filtration. Single-cell suspensions are plated and placed directly under a microscope within an incubator chamber for live-cell imaging. Sixteen 650 &mu;m x 700 &mu;m fields in a 4x4 configuration from each well of a 6-well plate are imaged every 15 min for 5 days. Time-lapse images are examined directly to measure cellular behaviors that can include mechanism and frequency of cell colony formation within the first 24 hr of plating the cells (aggregation versus cell proliferation), incidence of apoptosis, and phasing of morphological changes. Single-cell tracking is used to generate cell fate maps for measurement of individual cell lifetimes and investigation of cell division patterns. Quantitative data are statistically analyzed to assess for significant differences in behavior correlated with specific genetic lesions.

Time-lapse imaging is used to assess behavior of primary preneoplastic mammary epithelial cells derived from genetically engineered mouse models of breast cancer risk to determine if there are correlations between specific behavioral parameters and distinct genetic lesions.

Time-lapse  imaging can be used to compare behavior of cultured primary preneoplastic  mammary epithelial cells derived from different genetically ...

Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

Certain classes of chemotherapies may exert acute vascular changes that may progress into long-term conditions that may predispose the patient to an increased risk of vascular morbidity.&#160;Yet, albeit&#160;the mounting clinical evidence, there is a paucity of clear studies of vascular toxicity and therefore the etiology of a heterogeneous group of vascular/cardiovascular disorders remains to be elucidated. Moreover, the mechanism that may underlie vascular toxicity can completely differ from the principles of chemotherapy-induced cardiotoxicity, which is related to direct myocyte injury. We have established a real-time, in vivo molecular imaging platform&#160;to evaluate&#160;the potential&#160;acute&#160;vascular toxicity of anti-cancer therapies.
We have set up a platform of in vivo, high-resolution molecular imaging&#160;in mice,&#160;suitable for visualizing vasculature within confined organs and reference blood vessels within the same individuals whereas each individual serve as its own control. Blood vessel walls were impaired after doxorubicin administration, representing a unique mechanism of vascular toxicity that may be the early event in end-organ injury. Herein, the method of fibered confocal fluorescent microscopy (FCFM) based imaging is described, which provides an innovative mode to understand physiological phenomena at the cellular and sub-cellular levels in animal subjects.

Chemotherapy-induced Vascular Toxicity - Real-time In vivo Imaging of Vessel Impairment

We herein describe the method of fibered confocal fluorescent microscopy (FCFM) based imaging, which provides an innovative mode to understand physiological phenomena at the cellular and sub-cellular levels in animal subjects.

Certain classes of chemotherapies may exert acute vascular changes that may progress into long-term conditions that may predispose the patient to an ...

Confocal Time Lapse Imaging as an Efficient Method for the Cytocompatibility Evaluation of Dental Composites

It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The objective of this study was to use 3D CLSM time lapse confocal imaging to assess the in vitro biocompatibility of dental composites. This method provides an accurate and sensitive indication of viable cell rate in contact with dental composite extracts. The ELS extra low shrinkage, a dental composite used for direct restoration, has been taken as example. In vitro assessment was performed on cultured primary human gingival fibroblast cells using Live/Dead staining. Images were obtained with the FV10i confocal biological inverted system and analyzed with the FV10-ASW 3.1 Software. Image analysis showed a very slight cytotoxicity in the presence of the tested composite after 5 hours of time lapse. A slight decrease of cell viability was shown in contact with the tested composite extracts compared to control cells. The findings highlighted the use of 3D CLSM time lapse imaging as a sensitive method to qualitatively and quantitatively evaluate the biocompatibility behavior of dental composites.

The most studied aspect of the biocompatibility of dental composites is their cytotoxicity 3D CLSM time lapse imaging combined with fluorescent signal quantification allows sensitive evaluation of the cell fate over time. Utilizing this method could be an efficient tool to assess the cytocompatibility of dental composites.

It is generally accepted that in vitro cell material interaction is a useful criterion in the evaluation of dental material biocompatibility. The ...

Real-time X-ray Imaging of Lung Fluid Volumes in Neonatal Mouse Lung

At birth, the lung undergoes a profound phenotypic switch from secretion to absorption, which allows for adaptation to breathing independently. Promoting and sustaining this phenotype is critically important in normal alveolar growth and gas exchange throughout life. Several in vitro studies have characterized the role of key regulatory proteins, signaling molecules, and steroid hormones that can influence the rate of lung fluid clearance. However, in vivo examinations must be performed to evaluate whether these regulatory factors play important physiological roles in regulating perinatal lung liquid absorption. As such, the utilization of real time X-ray imaging to determine perinatal lung fluid clearance, or pulmonary edema, represents a technological advancement in the field. Herein, we explain and illustrate an approach to assess the rate of alveolar lung fluid clearance and alveolar flooding in C57BL/6 mice at post natal day 10 using X-ray imaging and analysis. Successful implementation of this protocol requires prior approval from institutional animal care and use committees (IACUC), an in vivo small animal X-ray imaging system, and compatible molecular imaging software.

We present a protocol to assess the rate of alveolar fluid clearance or pulmonary edema in neonatal mouse lung using X-ray imaging technology.

At birth, the lung undergoes a profound phenotypic switch from secretion to absorption, which allows for adaptation to breathing independently. Promoting ...

Evaluation of Lung Metastasis in Mouse Mammary Tumor Models by Quantitative Real-time PCR

Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated death 1. Common sites of metastatic spread include lung, lymph node, brain, and bone 2. Mechanisms that drive metastasis are intense areas of cancer research. Consequently, effective assays to measure metastatic burden in distant sites of metastasis are instrumental for cancer research. Evaluation of lung metastases in mammary tumor models is generally performed by gross qualitative observation of lung tissue following dissection. Quantitative methods of evaluating metastasis are currently limited to ex vivo and in vivo imaging based techniques that require user defined parameters. Many of these techniques are at the whole organism level rather than the cellular level 3-6. Although newer imaging methods utilizing multi-photon microscopy are able to evaluate metastasis at the cellular level 7, these highly elegant procedures are more suited to evaluating mechanisms of dissemination rather than quantitative assessment of metastatic burden. Here, a simple in vitro method to quantitatively assess metastasis is presented. Using quantitative Real-time PCR (QRT-PCR), tumor cell specific mRNA can be detected within the mouse lung tissue.

This protocol describes how to use quantitative Real-time PCR (QRT-PCR) to detect tumor cell specific mRNA representing metastasis within the mouse lung tissue.

Metastatic disease is the spread of malignant tumor cells from the primary cancer site to a distant organ and is the primary cause of cancer associated ...

In vitro Time-lapse Live-Cell Imaging to Explore Cell Migration toward the Organ of Corti

To study the effects of mesenchymal stem cells (MSCs) on cell regeneration and treatment, this method tracks MSC migration and morphological changes after co-culture with cochlear epithelium. The organ of Corti was immobilized on a plastic coverslip by pressing a portion of the Reissner's membrane generated during the dissection. MSCs confined by a glass cylinder migrated toward cochlear epithelium when the cylinder was removed. Their predominant localization was observed in the modiolus of the organ of Corti, aligned in a direction similarly to that of the nerve fibers. However, some MSCs were localized in the limbus area and showed a horizontally elongated shape. In addition, migration into the hair cell area was increased, and the morphology of the MSCs changed to various forms after kanamycin treatment. In conclusion, the results of this study indicate that the coculture of MSCs with cochlear epithelium will be useful for the development of therapeutics via cell transplantation and for studies of cell regeneration that can examine various conditions and factors.

In this study, we present a real-time imaging method using confocal microscopy to observe cells moving toward damaged tissue by ex vivo incubation with the cochlear epithelium containing the organ of Corti.

To study the effects of mesenchymal stem cells (MSCs) on cell regeneration and treatment, this method tracks MSC migration and morphological changes after ...