We are grateful to Drs. Diane Palmieri and Patricia Steeg of NCI for providing us MDA-MB231Br cells. We thank Dr. Ralph Mason, Mr. Jason Reneau and Ms. Ramona Lopes for technical and collegial support. This work was supported in part by the DOD IDEA Awards W81XWH-08-1-0583 and W81XWH-12-1-0317. MRI experiments were performed in the Advanced Imaging Research Center, an NIH BTRP # P41-RR02584 facility, and ultrasound-guided intracardiac injection was performed with VisualSonics Vevo 770 under 1S10RR02564801.

All animal procedures were approved by the Institutional Animal Care and Use Committee of University of Texas Southwestern Medical Center.
1. Preparation of the MDA-MB231/Br-GFP Cells
<ol>
	<li>Retrieve and culture the MDA-MB231/Br-GFP cells (kindly provided by Drs. Palmieri and Steeg, NCI) in DMEM medium containing 10% FBS, 1% glutamine and 1% penicillin/streptomycin.</li>
	<li>Observe the condition of the cells and color of medium, and replace medium every 2-3 days.</li>
	<li>Trypsinize and collect the cells when 80% confluence is reached as outlined in steps 1.3.1-1.3.5:
	<ol>
		<li>Remove the old medium completely and add 5 ml PBS (1x) to wash the cells gently. Remove the PBS from the dish.</li>
		<li>Add 1.5 ml Trypsin in the dish; tilt the dish gently to ensure all the cells are covered by Trypsin. Put the dish back to the cell incubator and keep it at 37 &#176;C for 1 min.</li>
		<li>Take the dish out of incubator and observe the cells under optical microscope to ensure the cells detach from the dish.</li>
		<li>Add 3 ml medium to stop the effect of trypsin. Collect the cell mixture in a centrifuge tube. Centrifuge the mixture at 2,000 rpm&#160;for 5 min.</li>
		<li>Remove the medium carefully and resuspend the cells in 5 ml serum free medium until homogenous.</li>
	</ol>
	</li>
	<li>Count appropriate number of cells and resuspend them in serum free DMEM medium with a final concentration of 1.75 x 105 cells in 100 &#181;l volume.
	<ol>
		<li>Take 50 &#181;l cell mixture and add 50 &#181;l Trypan Blue. After mixing, take 10 &#181;l mixture and carefully add to the cell counting slide. Use multiple samples to ensure accurate cell number estimation.</li>
		<li>Stick in the cell counting slide, one end at a time and the cell counter starts counting automatically. Take average of all the counting results and calculate the total cell number.</li>
		<li>Centrifuge the cells again and resuspend them in the appropriate volume of serum free medium to result in the final concentration of 1.75 x 105 cells/100 &#181;l volume.</li>
	</ol>
	</li>
	<li>Place cells on ice prior to intracardiac injection.</li>
</ol>
2. Ultrasound Imaging-guided Intracardiac Injection
<ol>
	<li>Use female nude mice (BALB/c nu/nu) between 6-8 weeks old.</li>
	<li>Log in the imaging system. Initialize the transducer 704 (40 MHz).</li>
	<li>Start a new study and fill in the information.</li>
	<li>Anesthetize (3% isoflurane/100% O2 in an induction chamber) and maintain the animals with isoflurane (2%) in 100% O2 (1 dm3/min) during the whole procedure via a nose cone.&#160;Anesthesia is confirmed when no withdrawal reflex is observed with toe pinch.</li>
	<li>Set the temperature of the imaging table to 37 &#176;C. Tape the anesthetized mouse to the heated imaging table in supine position.</li>
	<li>Keep the ultrasound gel at 37 &#176;C prior to imaging. Apply the gel to the chest of the mouse.</li>
	<li>Mount the transducer in the holder. Lower the transducer till the desired imaging depth is reached. Move the stage until the left ventricle is identified with the ascending aorta as the landmark (Figure 1A). Lock the stage when a clear view of left ventricle is visualized.</li>
	<li>Draw 100 &#181;l of cell mixture into a 1 ml syringe with a 22 G needle. Place and fix the syringe on the syringe mount.</li>
	<li>Move the syringe forward towards the mouse chest and carefully move it side to side until the needle tip is in the imaging field of view (before entering the mouse).</li>
	<li>Adjust the needle height and angle to aim down the left ventricle.</li>
	<li>Penetrate the syringe needle into intercoastal space&#160;&#160;promptly through skin and muscle layers into the left ventricle under the guidance of ultrasound imaging. 
	An indication of successful insertion of the needle into the left ventricle is the reflux of fresh arterial blood (pink color in contrast to dark red venous blood) into the syringe</li>
	<li>Inject the cell mixture slowly (Figure 1B).</li>
	<li>Upon completion, withdraw the needle, lift up the transducer, clean the ultrasound gel with dampened gauze and remove tape.</li>
	<li>Prepare a clean cage with a preheated pad.</li>
	<li>Place the animal on the pad and observe the animal till full recovery.</li>
	<li>Monitor the behavior of the animal every 24 hr for two days.</li>
	<li>General conditions and neurologic signs of complications in experimental mice are routinely monitored.</li>
</ol>
3. MRI Monitoring of Intracranial Tumor Development
<ol>
	<li>Use a 9.4 Tesla magnet to monitor intracranial development of brain metastases.</li>
	<li>Initiate MRI two weeks after tumor implantation and repeat once a week for up to three weeks.</li>
	<li>Sedate the animals with 3% isoflurane and maintain them under general anesthesia (1.5% isoflurane).</li>
	<li>Monitor and maintain the animal body temperature and respiration constant throughout the experiment.</li>
	<li>High resolution multislice (14 slices with 1&#160;mm&#160;thick, no gap) T1- and T2-weighted coronal images, covering the region from the frontal lobe to the posterior fossa, are acquired with the following parameters: T1-weighted images: spin echo multiple slice (SEMS), TR/TE = 400 msec/20 msec, matrix: 256 x 256, FOV 20 x 20 mm, in plane resolution: 78 x 78 &#181;m2. T2-weighted images: fast spin echo multiple slice (FSEMS) sequences, TR/TE = 2500 msec/48 msec, 8 echo trains, matrix: 256 x 256, FOV 20 x 20 mm, in plane resolution: 78 x 78 &#181;m&#160;28,9. 
	Tumor lesions appear brighter than normal brain tissues on T2-weighted images.</li>
	<li>Tumor size is determined on T2-weighted images by manually outlining the enhancing portion of the mass on each image by using MATLAB programs written by us8. 
	Given most of the tumor diameters are smaller than the slice thickness (1 mm), the tumor size is presented as in plane area rather than the volume.</li>
</ol>
4. H&#38;E Staining Confirming the Metastases
<ol>
	<li>Sacrifice the mice immediately after the last MR scan, dissect the tumor-bearing brains and embed it in O.C.T medium and frozen in -80 &#176;C.</li>
	<li>Section a series of 10 &#181;m-thick coronal brain specimens with cryostat.</li>
	<li>Perform H&#38;E staining on the brain sections.</li>
</ol>

<ol>
	<li>Schouten, L. J., 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=Incidence+of+brain+metastases+in+a+cohort+of+patients+with+carcinoma+of+the+breast,+colon,+kidney,+and+lung+and+melanoma.">Incidence of brain metastases in a cohort of patients with carcinoma of the breast, colon, kidney, and lung and melanoma.</a> Cancer. 94, 2698-2705 (2002).</li><li>Lin, N. U., 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=CNS+metastases+in+breast+cancer.">CNS metastases in breast cancer.</a> J. Clin. Oncol. 22, 3608-3617 (2004).</li><li>Eichler, A. F., 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=The+biology+of+brain+metastases-translation+to+new+therapies.">The biology of brain metastases-translation to new therapies.</a> Nat. Rev. Clin. Oncol. , (2011).</li><li>Lockman, P. R., 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=Heterogeneous+blood-tumor+barrier+permeability+determines+drug+efficacy+in+experimental+brain+metastases+of+breast+cancer.">Heterogeneous blood-tumor barrier permeability determines drug efficacy in experimental brain metastases of breast cancer.</a> Clin. Cancer Res. 16, 5664-5678 (2010).</li><li>Yoneda, T., 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=A+bone-seeking+clone+exhibits+different+biological+properties+from+the+MDA-MB-231+parental+human+breast+cancer+cells+and+a+brain-seeking+clone+in+vivo+and+in.">A bone-seeking clone exhibits different biological properties from the MDA-MB-231 parental human breast cancer cells and a brain-seeking clone in vivo and in.</a> 16, 1486-1495 (2001).</li><li>Palmieri, D., 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=Her-2+overexpression+increases+the+metastatic+outgrowth+of+breast+cancer+cells+in+the+brain.">Her-2 overexpression increases the metastatic outgrowth of breast cancer cells in the brain.</a> Cancer Res. 67, 4190-4198 (2007).</li><li>Percy, D. B., 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=In+vivo+characterization+of+changing+blood-tumor+barrier+permeability+in+a+mouse+model+of+breast+cancer+metastasis:+a+complementary+magnetic+resonance+imaging+approach.">In vivo characterization of changing blood-tumor barrier permeability in a mouse model of breast cancer metastasis: a complementary magnetic resonance imaging approach.</a> Invest. Radiol. 46, 718-725 (2011).</li><li>Zhou, H., 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=Longitudinal+MRI+evaluation+of+intracranial+development+and+vascular+characteristics+of+breast+cancer+brain+metastases+in+a+mouse+model.">Longitudinal MRI evaluation of intracranial development and vascular characteristics of breast cancer brain metastases in a mouse model.</a> PLoS One. 8, (2013).</li><li>Zhou, H., 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=Dynamic+near-infrared+optical+imaging+of+2-deoxyglucose+uptake+by+intracranial+glioma+of+athymic+mice.">Dynamic near-infrared optical imaging of 2-deoxyglucose uptake by intracranial glioma of athymic mice.</a> PLoS One. 4, (2009).</li><li>Zhang, R. D., 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=Differential+permeability+of+the+blood-brain+barrier+in+experimental+brain+metastases+produced+by+human+neoplasms+implanted+into+nude+mice.">Differential permeability of the blood-brain barrier in experimental brain metastases produced by human neoplasms implanted into nude mice.</a> Am. J. Pathol. 141, 1115-1124 (1992).</li><li>Mason, R. 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=Tumor+oximetry:+comparison+of+19F+MR+EPI+and+electrodes.">Tumor oximetry: comparison of 19F MR EPI and electrodes.</a> Adv. Exp. Med. Biol. 530, 19-27 (2003).</li><li>Gril, B., 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=Pazopanib+reveals+a+role+for+tumor+cell+B-Raf+in+the+prevention+of+HER2++breast+cancer+brain+metastasis.">Pazopanib reveals a role for tumor cell B-Raf in the prevention of HER2+ breast cancer brain metastasis.</a> Clin. Cancer Res. 17, 142-153 (2010).</li></ol>

No conflicts of interest declared.

In the present study, we have demonstrated that ultrasound imaging-guided left ventricular injection ensures the accuracy so that every animal in this study developed brain metastases and no animal death was observed.&#160;The beauty of image-guided injection is that the path of needle penetration of skin and finally into the left ventricle can be monitored and adjusted under image, which is distinct from the manual procedure requiring strict anatomic landmarks to follow.
Current understanding...

Brain metastasis is the most common intracranial malignancy in adults. The prognosis is extremely poor, with a median survival of 4-6 months even with aggressive treatment. Breast cancer is one of the three major primary cancers with a high morbidity of brain metastasis1-3. Several brain-tropic breast cancer lines are capable of developing brain metastases after intracardiac or intracarotid injection4. Direct injection of tumor cells into the left ventricle can bypass the lung capillary bed and thus increase the incidence of forming brain metastases while minimizing visceral metastases.&#160;The MDA-MB231Br line is one of the most widely used human breast cancer lines to develop brain metastasis in rodent models5,6.
Like many other studies4,7, we have performed a manual procedure of intracardiac injection in our previous studies. However, only 50% successful rate was obtained with the manual injection and a fraction of mice died from the repeated invasive procedures if prior trials failed. Here, we are introducing the use of an imaging-guided procedure to secure the injection of brain-seeking breast cancer cells into the left ventricle of athymic mice. Longitudinal high resolution MRI is applied to follow intracranial development of brain metastases.

<table border="0" cellpadding="0" cellspacing="0" width="783">
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	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">DMEM</td>
			<td style="width:136px;">HyClone</td>
			<td style="width:87px;">SH30022.01</td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">Trypsin</td>
			<td style="width:136px;">Mediatech</td>
			<td style="width:87px;">25-051-C1</td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">Automatic cell counter</td>
			<td style="width:136px;">Biorad</td>
			<td style="width:87px;">TC10</td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">Isoflurane</td>
			<td style="width:136px;">Baxter International Inc.</td>
			<td style="width:87px;">1001936060</td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:413px;">VisualSonics Vevo 770 High-Resolution Imaging System </td>
			<td>Visual Sonics Inc.</td>
			<td></td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">9.4T horizontal bore magnet with a Varian INOVA Unity system </td>
			<td>Agilent</td>
			<td style="width:87px;"> </td>
			<td style="width:147px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">O.C.T Compound</td>
			<td>Sakura Finetek USA</td>
			<td style="width:87px;">4583</td>
			<td style="width:147px;"> </td>
		</tr>
	</tbody>
</table>

ultrasound imaging-guided intracardiac injection to develop a mouse model of breast cancer brain metastases followed by longitudinal mri

Breast cancer brain metastasis, occurring in 30% of breast cancer patients at stage IV, is associated with high mortality. The median survival is only 6 months. It is critical to have suitable animal models to mimic the hemodynamic spread of the metastatic cells in the clinical scenario. Here, we are introducing the use of small animal ultrasound imaging to guide an accurate injection of brain tropical breast cancer cells into the left ventricle of athymic nude mice. Longitudinal MRI is used to assessing intracranial initiation and growth of brain metastases. Ultrasound-guided intracardiac injection ensures not only an accurate injection and hereby a higher successful rate but also significantly decreased mortality rate, as compared to our previous manual procedure. In vivo high resolution MRI allows the visualization of hyperintense multifocal lesions, as small as 310 &#181;m in diameter on T2-weighted images at 3 weeks post injection. Follow-up MRI reveals intracranial tumor growth and increased number of metastases that distribute throughout the whole brain.

With the high spatial resolution of MRI (78 &#181;m in plane resolution), hyperintense lesions can be identified as small as 310 &#181;m in diameter (Figure&#160;2). Since the metastases in this study are very small and development of necrosis and edema is minimal, the hyperintense lesion on T2-weighted images truly represented the tumor mass.
Longitudinal MRI studies allow in vivo noninvasive evaluation of tumor growth. As shown in Figure 3</strong...

Watch this Scientific Journal Video about Ultrasound Imaging-guided Intracardiac Injection to Develop a Mouse Model of Breast Cancer Brain Metastases Followed by Longitudinal MRI at JoVE.com

Ultrasound Imaging-guided Intracardiac Injection to Develop a Mouse Model of Breast Cancer Brain Metastases Followed by Longitudinal MRI

A breast cancer brain metastasis mouse model is established with ultrasound imaging-guided intracardiac injection of MDA-MB231/Br-GFP cells. Development of multifocal intracranial metastases has been monitored longitudinally using high-resolution 9.4 T MRI.

Breast cancer brain metastasis, occurring in 30% of breast cancer patients at stage IV, is associated with high mortality. The median survival is only 6 ...

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18.6K Views.  University of Texas Southwestern Medical Center. A breast cancer brain metastasis mouse model is established with ultrasound imaging-guided intracardiac injection of MDA-MB231/Br-GFP cells. Development of multifocal intracranial metastases has been monitored longitudinally using high-resolution 9.4 T MRI.

Video: Ultrasound Imaging-guided Intracardiac Injection to Develop a Mouse Model of Breast Cancer Brain Metastases Followed by Longitudinal MRI

In vivo Bioluminescence Imaging of Tumor Hypoxia Dynamics of Breast Cancer Brain Metastasis in a Mouse Model

It is well recognized that tumor hypoxia plays an important role in promoting malignant progression and affecting therapeutic response negatively. There is little knowledge about in situ, in vivo, tumor hypoxia during intracranial development of malignant brain tumors because of lack of efficient means to monitor it in these deep-seated orthotopic tumors. Bioluminescence imaging (BLI), based on the detection of light emitted by living cells expressing a luciferase gene, has been rapidly adopted for cancer research, in particular, to evaluate tumor growth or tumor size changes in response to treatment in preclinical animal studies. Moreover, by expressing a reporter gene under the control of a promoter sequence, the specific gene expression can be monitored non-invasively by BLI. Under hypoxic stress, signaling responses are mediated mainly via the hypoxia inducible factor-1&alpha; (HIF-1&alpha;) to drive transcription of various genes. Therefore, we have used a HIF-1&alpha; reporter construct, 5HRE-ODD-luc, stably transfected into human breast cancer MDA-MB231 cells (MDA-MB231/5HRE-ODD-luc). In vitro HIF-1&alpha; bioluminescence assay is performed by incubating the transfected cells in a hypoxic chamber (0.1% O2) for 24 hr before BLI, while the cells in normoxia (21% O2) serve as a control. Significantly higher photon flux observed for the cells under hypoxia suggests an increased HIF-1&alpha; binding to its promoter (HRE elements), as compared to those in normoxia. Cells are injected directly into the mouse brain to establish a breast cancer brain metastasis model. In vivo bioluminescence imaging of tumor hypoxia dynamics is initiated 2 wks after implantation and repeated once a week. BLI reveals increasing light signals from the brain as the tumor progresses, indicating increased intracranial tumor hypoxia. Histological and immunohistochemical studies are used to confirm the in vivo imaging results. Here, we will introduce approaches of in vitro HIF-1&alpha; bioluminescence assay, surgical establishment of a breast cancer brain metastasis in a nude mouse and application of in vivo bioluminescence imaging to monitor intracranial tumor hypoxia.

In vivo Bioluminescence Imaging of Tumor Hypoxia Dynamics of Breast Cancer Brain Metastasis in a Mouse Model

Bioluminescence imaging of hypoxia inducible factor-1&alpha; activity is applied to monitor intracranial tumor hypoxia development in a breast cancer brain metastasis mouse model.

It is well recognized that tumor hypoxia plays an important role in promoting malignant progression and affecting therapeutic response negatively. There ...

Combination Radiotherapy in an Orthotopic Mouse Brain Tumor Model

Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors1. In recent years there has been substantial progress in the understanding of the mechanics of tumor invasion, and direct intracerebral inoculation of tumor provides the opportunity of observing the invasive process in a physiologically appropriate environment2. As far as human brain tumors are concerned, the orthotopic models currently available are established either by stereotaxic injection of cell suspensions or implantation of a solid piece of tumor through a complicated craniotomy procedure3. In our technique we harvest cells from tissue culture to create a cell suspension used to implant directly into the brain. The duration of the surgery is approximately 30 minutes, and as the mouse needs to be in a constant surgical plane, an injectable anesthetic is used. The mouse is placed in a stereotaxic jig made by Stoetling (figure 1). After the surgical area is cleaned and prepared, an incision is made; and the bregma is located to determine the location of the craniotomy. The location of the craniotomy is 2 mm to the right and 1 mm rostral to the bregma. The depth is 3 mm from the surface of the skull, and cells are injected at a rate of 2 &mu;l every 2 minutes. The skin is sutured with 5-0 PDS, and the mouse is allowed to wake up on a heating pad. From our experience, depending on the cell line, treatment can take place from 7-10 days after surgery. Drug delivery is dependent on the drug composition. For radiation treatment the mice are anesthetized, and put into a custom made jig. Lead covers the mouse's body and exposes only the brain of the mouse. The study of tumorigenesis and the evaluation of new therapies for GBM require accurate and reproducible brain tumor animal models. Thus we use this orthotopic brain model to study the interaction of the microenvironment of the brain and the tumor, to test the effectiveness of different therapeutic agents with and without radiation.

The purpose of this article is to describe the use of an orthotopic glioblastoma model for chemoradiation studies. This article will go though cell processing, implanting, and radiotherapy of the mouse using an intracranial model.

Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors1. In recent years there has been substantial progress in the ...

MRI-guided Disruption of the Blood-brain Barrier using Transcranial Focused Ultrasound in a Rat Model

Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is an increasingly investigated technique for circumventing the BBB1-5. The BBB is a significant obstacle to pharmaceutical treatments of brain disorders as it limits the passage of molecules from the vasculature into the brain tissue to molecules less than approximately 500 Da in size6. FUS induced BBB disruption (BBBD) is temporary and reversible4 and has an advantage over chemical means of inducing BBBD by being highly localized. FUS induced BBBD provides a means for investigating the effects of a wide range of therapeutic agents on the brain, which would not otherwise be deliverable to the tissue in sufficient concentration. While a wide range of ultrasound parameters have proven successful at disrupting the BBB2,5,7, there are several critical steps in the experimental procedure to ensure successful disruption with accurate targeting. This protocol outlines how to achieve MRI-guided FUS induced BBBD in a rat model, with a focus on the critical animal preparation and microbubble handling steps of the experiment.

Microbubble-mediated focused ultrasound disruption of the blood-brain barrier (BBB) is a promising technique for non-invasive targeted drug delivery in the brain1-3. This protocol outlines the experimental procedure for MRI-guided transcranial BBB disruption in a rat model.

Focused ultrasound (FUS) disruption of the blood-brain barrier (BBB) is an increasingly investigated technique for circumventing the BBB1-5. The BBB is a ...

Multi-modal Imaging of Angiogenesis in a Nude Rat Model of Breast Cancer Bone Metastasis Using Magnetic Resonance Imaging, Volumetric Computed Tomography and Ultrasound

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell proliferation in the bone marrow cavity as well as for interaction of tumor and bone cells resulting in local bone destruction. Our aim was to develop a model of experimental bone metastasis that allows in vivo assessment of angiogenesis in skeletal lesions using non-invasive imaging techniques.
For this purpose, we injected 105 MDA-MB-231 human breast cancer cells into the superficial epigastric artery, which precludes the growth of metastases in body areas other than the respective hind leg1. Following 25-30 days after tumor cell inoculation, site-specific bone metastases develop, restricted to the distal femur, proximal tibia and proximal fibula1. Morphological and functional aspects of angiogenesis can be investigated longitudinally in bone metastases using magnetic resonance imaging (MRI), volumetric computed tomography (VCT) and ultrasound (US).
MRI displays morphologic information on the soft tissue part of bone metastases that is initially confined to the bone marrow cavity and subsequently exceeds cortical bone while progressing. Using dynamic contrast-enhanced MRI (DCE-MRI) functional data including regional blood volume, perfusion and vessel permeability can be obtained and quantified2-4. Bone destruction is captured in high resolution using morphological VCT imaging. Complementary to MRI findings, osteolytic lesions can be located adjacent to sites of intramedullary tumor growth. After contrast agent application, VCT angiography reveals the macrovessel architecture in bone metastases in high resolution, and DCE-VCT enables insight in the microcirculation of these lesions5,6. US is applicable to assess morphological and functional features from skeletal lesions due to local osteolysis of cortical bone. Using B-mode and Doppler techniques, structure and perfusion of the soft tissue metastases can be evaluated, respectively. DCE-US allows for real-time imaging of vascularization in bone metastases after injection of microbubbles7.
In conclusion, in a model of site-specific breast cancer bone metastases multi-modal imaging techniques including MRI, VCT and US offer complementary information on morphology and functional parameters of angiogenesis in these skeletal lesions.

In the pathogenesis of bone metastasis, angiogenesis is a crucial process and therefore represents a target for imaging and therapy. Here, we present a rat model of site-specific breast cancer bone metastasis and describe strategies to non-invasively image angiogenesis in vivo using magnetic resonance imaging, volumetric computed tomography and ultrasound.

Angiogenesis is an essential feature of cancer growth and metastasis formation. In bone metastasis, angiogenic factors are pivotal for tumor cell ...

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 ...

Initiation of Metastatic Breast Carcinoma by Targeting of the Ductal Epithelium with Adenovirus-Cre: A Novel Transgenic Mouse Model of Breast Cancer

Breast cancer is a heterogeneous disease involving complex cellular interactions between the developing tumor and immune system, eventually resulting in exponential tumor growth and metastasis to distal tissues and the collapse of anti-tumor immunity. Many useful animal models exist to study breast cancer, but none completely recapitulate the disease progression that occurs in humans. In order to gain a better understanding of the cellular interactions that result in the formation of latent metastasis and decreased survival, we have generated an inducible transgenic mouse model of YFP-expressing ductal carcinoma that develops after sexual maturity in immune-competent mice and is driven by consistent, endocrine-independent oncogene expression. Activation of YFP, ablation of p53, and expression of an oncogenic form of K-ras was achieved by the delivery of an adenovirus expressing Cre-recombinase into the mammary duct of sexually mature, virgin female mice. Tumors begin to appear 6 weeks after the initiation of oncogenic events. After tumors become apparent, they progress slowly for approximately two weeks before they begin to grow exponentially. After 7-8 weeks post-adenovirus injection, vasculature is observed connecting the tumor mass to distal lymph nodes, with eventual lymphovascular invasion of YFP+ tumor cells to the distal axillary lymph nodes. Infiltrating leukocyte populations are similar to those found in human breast carcinomas, including the presence of &#945;&#946; and &#947;&#948; T cells, macrophages and MDSCs. This unique model will facilitate the study of cellular and immunological mechanisms involved in latent metastasis and dormancy in addition to being useful for designing novel immunotherapeutic interventions to treat invasive breast cancer.

Activation of latent mutations with adenovirus-Cre into the mammary ductal system results in a clinically relevant metastatic breast cancer. Incorporation of a YFP promoter allows tracking of distal metastatic tumor cells. This model is useful to study latent metastasis, anti-tumor immunity, and for designing novel immunotherapies to treat breast cancer.

Breast cancer is a heterogeneous disease involving complex cellular interactions between the developing tumor and immune system, eventually resulting in ...

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional (3D) Model

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the extracellular matrix (ECM) has been demonstrated to be a critical regulator of cell behavior in culture and homeostasis in vivo. The current approach of culturing cells on two-dimensional (2D), plastic surfaces results in the disturbance and loss of complex interactions between cells and their microenvironment. Through the use of three-dimensional (3D) culture assays, the conditions for cell-microenvironment interaction are established resembling the in vivo microenvironment. This article provides a detailed methodology to grow breast cancer cells in a 3D basement membrane protein matrix, exemplifying the potential of 3D culture in the assessment of cell invasion into the surrounding environment. In addition, we discuss how these 3D assays have the potential to examine the loss of signaling molecules that regulate epithelial morphology by immunostaining procedures. These studies aid to identify important mechanistic details into the processes regulating invasion, required for the spread of breast cancer.

Quantification of Breast Cancer Cell Invasiveness Using a Three-dimensional 3D Model

This article provides detailed methodologies for the use of three-dimensional (3D) assays to quantify breast cancer cell invasion. Specifically, we discuss the procedures required to set up such assays, quantification, and data analysis, as well as methods to examine the loss of membrane integrity that occurs when cells invade.

It is now well known that the cellular and tissue microenvironment are critical regulators influencing tumor initiation and progression. Moreover, the ...

Acute Brain Trauma in Mice Followed By Longitudinal Two-photon Imaging

Although acute brain trauma often results from head damage in different accidents and affects a substantial fraction of the population, there is no effective treatment for it yet. Limitations of currently used animal models impede understanding of the pathology mechanism. Multiphoton microscopy allows studying cells and tissues within intact animal brains longitudinally under physiological and pathological conditions. Here, we describe two models of acute brain injury studied by means of two-photon imaging of brain cell behavior under posttraumatic conditions. A selected brain region is injured with a sharp needle to produce a trauma of a controlled width and depth in the brain parenchyma. Our method uses stereotaxic prick with a syringe needle, which can be combined with simultaneous drug application. We propose that this method can be used as an advanced tool to study cellular mechanisms of pathophysiological consequences of acute trauma in mammalian brain in vivo. In this video, we combine acute brain injury with two preparations: cranial window and skull thinning. We also discuss advantages and limitations of both preparations for multisession imaging of brain regeneration after trauma.

Acute brain trauma is a severe injury that has no adequate treatment to date. Multiphoton microscopy allows studying longitudinally the process of acute brain trauma development and probing therapeutical strategies in rodents. Two models of acute brain trauma studied with in vivo two-photon imaging of brain are demonstrated in this protocol.

Although acute brain trauma often results from head damage in different accidents and affects a substantial fraction of the population, there is no ...

A Preclinical Murine Model of Hepatic Metastases

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, murine pancreatic tumor model of hepatic metastases via a hemispleen injection of syngeneic murine pancreatic tumor cells is described. This model mimics many of the clinical conditions in patients with metastatic disease to the liver. Mice consistently develop metastases in the liver allowing for investigation of the metastatic process, experimental therapy testing, and tumor immunology research.

A preclinical, murine model of hepatic metastases performed via a hemispleen injection technique.

Numerous murine models have been developed to study human cancers and advance the understanding of cancer treatment and development. Here, a preclinical, ...

Orthotopic Injection of Breast Cancer Cells into the Mammary Fat Pad of Mice to Study Tumor Growth.

Breast cancer growth can be studied in mice using a plethora of models. Genetic manipulation of breast cancer cells may provide insights into the functions of proteins involved in oncogenic progression or help to discover new tumor suppressors. In addition, injecting cancer cells into mice with different genotypes might provide a better understanding of the importance of the stromal compartment. Many models may be useful to investigate certain aspects of disease progression but do not recapitulate the entire cancerous process. In contrast, breast cancer cells engraftment to the mammary fat pad of mice better recapitulates the location of the disease and presence of the proper stromal compartment and therefore better mimics human cancerous disease. In this article, we describe how to implant breast cancer cells into mice orthotopically and explain how to collect tissues to analyse the tumor milieu and metastasis to distant organs. Using this model, many aspects (growth, angiogenesis, and metastasis) of cancer can be investigated simply by providing a proper environment for tumor cells to grow.

Cancer is a complex disease that is influenced by the tissue surrounding the tumor as well as local pro- and anti-inflammatory mediators. Therefore, orthotropic injection models, rather than subcutaneous models may be useful to study cancer progression in a manner that better mimics human pathology.