This research was supported by the Deutsche Krebshilfe (Max Eder Group to AN: 110972), a DGVS doctoral thesis scholarship (to SMB), and an Else-Kr&#246;ner-Fresenius-Foundation scholarship (to RGG) at the University Medical Center Goettingen. We thank Jutta Blumberg and Ulrike Wegner for expert technical assistance. We also thank all animal technicians at the animal facility of the University Medical Center Goettingen for mouse keeping. All experiments were performed according to German animal welfare regulations.

This protocol is in accordance with the animal care guidelines at the University Medical Centre Goettingen, Germany (33.9-42502-04-15/2056). Depending on specific requirements of individual animal review boards, some of the protocol steps could be modified accordingly.
1. Abdominal Palpation of KPC Mice
<ol>
	<li>To avoid unnecessary ultrasound scans, palpate the mouse abdomen to identify mice which might possibly bear an intraabdominal lesion and should subsequently undergo abdominal ultras...

<ol>
	<li>Kersten, K., de Visser, K. E., van Miltenburg, M. H., Jonkers, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetically+engineered+mouse+models+in+oncology+research+and+cancer+medicine.">Genetically engineered mouse models in oncology research and cancer medicine.</a> EMBO Molecular Medicine. 9 (2), 137-153 (2017).</li><li>Olive, K. P., Politi, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Translational therapeutics in genetically engineered mouse models of cancer. (2), 131-143 (2014).</li><li>Westphalen, C. B., Olive, K. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetically+engineered+mouse+models+of+pancreatic+cancer.">Genetically engineered mouse models of pancreatic cancer.</a> The Cancer Journal. 18 (6), 502-510 (2012).</li><li>Hingorani, S. 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=Trp53R172H+and+KrasG12D+cooperate+to+promote+chromosomal+instability+and+widely+metastatic+pancreatic+ductal+adenocarcinoma+in+mice.">Trp53R172H and KrasG12D cooperate to promote chromosomal instability and widely metastatic pancreatic ductal adenocarcinoma in mice.</a> Cancer Cell. 7 (5), 469-483 (2005).</li><li>Frese, K. K., 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=nab-Paclitaxel+potentiates+gemcitabine+activity+by+reducing+cytidine+deaminase+levels+in+a+mouse+model+of+pancreatic+cancer.">nab-Paclitaxel potentiates gemcitabine activity by reducing cytidine deaminase levels in a mouse model of pancreatic cancer.</a> Cancer Discovery. 2 (3), 260-269 (2012).</li><li>Paredes, J. L., 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+non-invasive+method+of+quantifying+pancreatic+volume+in+mice+using+micro-MRI.">A non-invasive method of quantifying pancreatic volume in mice using micro-MRI.</a> PLoS One. 9 (3), e92263 (2014).</li><li>Boj, S. 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=Organoid+models+of+human+and+mouse+ductal+pancreatic+cancer.">Organoid models of human and mouse ductal pancreatic cancer.</a> Cell. 160 (1-2), 324-338 (2015).</li><li>Aung, W., 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=Immunotargeting+of+Integrin+alpha6beta4+for+Single-Photon+Emission+Computed+Tomography+and+Near-Infrared+Fluorescence+Imaging+in+a+Pancreatic+Cancer+Model.">Immunotargeting of Integrin alpha6beta4 for Single-Photon Emission Computed Tomography and Near-Infrared Fluorescence Imaging in a Pancreatic Cancer Model.</a> Molecular Imaging. 15, (2016).</li><li>Akladios, C. Y., 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=Contribution+of+microCT+structural+imaging+to+preclinical+evaluation+of+hepatocellular+carcinoma+chemotherapeutics+on+orthotopic+graft+in+ACI+rats.">Contribution of microCT structural imaging to preclinical evaluation of hepatocellular carcinoma chemotherapeutics on orthotopic graft in ACI rats.</a> Bulletin du Cancer. 98 (2), 120-132 (2011).</li><li>Neesse, 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=CTGF+antagonism+with+mAb+FG-3019+enhances+chemotherapy+response+without+increasing+drug+delivery+in+murine+ductal+pancreas+cancer.">CTGF antagonism with mAb FG-3019 enhances chemotherapy response without increasing drug delivery in murine ductal pancreas cancer.</a> Proceedings of the National Academy of Science USA. 110 (30), 12325-12330 (2013).</li><li>Sastra, S. A., Olive, K. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+murine+pancreatic+tumors+by+high-resolution+ultrasound.">Quantification of murine pancreatic tumors by high-resolution ultrasound.</a> Methods in Molecular Biology. 980, 249-266 (2013).</li></ol>

With this protocol, a detailed description for quantifying pancreatic tumors using high-resolution abdominal ultrasound imaging in genetically engineered mouse models is provided. Recently, Sastra et al. published a detailed description how to quantify pancreatic tumors in mouse models, but no visualized instructions about the preparation and handling as prerequisite for all further steps were shown11. The overall goal of this manuscript is to provide a comprehensive visual guide for high...

Genetically engineered mouse models have gained an increasing importance in cancer research due to their ability to closely recapitulate the complex nature of human carcinogenesis1,2,3. One of the most frequently used models to study pancreatic cancer development, progression and therapeutic response is characterized by an activating mutation in the Kras oncogene combined with an inactivation of the tumor suppressor p534. This LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model mimics the step-wise progression from pre-invasive pancreatic intraepithelial neoplasia (PanIN) lesions to invasive carcinoma. Phenotypically, nearly all mice develop PDAC within the first six months after birth. However, compared to transplanted models, the KPC model reveals a highly variable tumor onset from 8 weeks to several months4. Once pancreatic tumors reach a certain size (5-9 mm in diameter), tumor growth accelerates rapidly and mice will have to be enrolled in preclinical trials5. Therefore, the exact detection of tumor onset and tumor size is an essential prerequisite for preclinical study logistics and therapy monitoring. In general, several approaches like magnetic resonance imaging (MRI)6, computed tomography scanning7,8,9 or high resolution ultrasound can be employed to conduct tumor screening and therapy10. Each technique has its advantages and drawbacks. Although MRI-or computed tomography (CT) -imaging allows high resolution data acquisition as well as accurate volume calculation, prolonged examination time under general sedation, and very expensive equipment is required, and does not permit frequent scanning over a long period of time. In contrast, small animal ultrasonography is an established method that can be employed to screen for abdominal pathologies in mice11. Advantages of this imaging method are short scanning times, high resolution, and the possibility to use doppler ultrasound or contrast enhanced ultrasound (CEUS) to visualize perfusion of organs in parallel. However, anatomical knowledge, 3D imagination and thorough practical training are required for correct image interpretation.
In the following article, a detailed protocol for utilizing high resolution ultrasound in the KPC model is provided. Furthermore, standard ultrasound images are depicted and labelled with organ structures to facilitate orientation for the investigator.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Visual Sonics Vevo2100 High Resolution Ultrasound System, including imaging stage and anesthesia line</td>
			<td>FUJIFILM VisualSonics Inc, Canada</td>
			<td>VS-11945</td>
			<td></td>
		</tr>
		<tr>
			<td>Vevo 2100 MicroScan Transducer MS-550-D (22-55MHz)</td>
			<td>FUJIFILM VisualSonics Inc, Canada</td>
			<td>VS-11874</td>
			<td></td>
		</tr>
		<tr>
			<td>Vevo Anesthesia System (anesthesia induction chamber with fresh and waste gas inlet)</td>
			<td>FUJIFILM VisualSonics Inc, Canada</td>
			<td>SA-12055</td>
			<td></td>
		</tr>
		<tr>
			<td>Vevo Imaging Station (working stage with nose cone for anesthesia supply)</td>
			<td>FUJIFILM VisualSonics Inc, Canada</td>
			<td>SA-11982</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;electronic pet clippers</td>
			<td>Panasonic Marketing Europe, Germany</td>
			<td>5025232484324</td>
			<td>Panasonic ER-PA10-s</td>
		</tr>
		<tr>
			<td>Labotect Hot plate</td>
			<td>Labor tech G&#246;ttingen, Germany</td>
			<td>13854</td>
			<td></td>
		</tr>
		<tr>
			<td>eye cream (ophthalmic ointment)</td>
			<td>Sch&#252;lke&#38;Mayr, Germany</td>
			<td>9080249</td>
			<td></td>
		</tr>
		<tr>
			<td>veterinary isoflurane</td>
			<td>Abbvie, Germany</td>
			<td>4831867</td>
			<td></td>
		</tr>
		<tr>
			<td>depilatory cream</td>
			<td>RB healthcare UK, United Kingdom</td>
			<td>8218535</td>
			<td></td>
		</tr>
		<tr>
			<td>70% ethanol (v/v) in distilled water</td>
			<td>TH. Geyer, Germany</td>
			<td>22941000</td>
			<td></td>
		</tr>
		<tr>
			<td>ultrasound gel</td>
			<td>Asmuth, Germany</td>
			<td>13477</td>
			<td></td>
		</tr>
		<tr>
			<td>tissue wipes</td>
			<td>Kimberly-Clark Germany, Germany</td>
			<td>7558</td>
			<td></td>
		</tr>
		<tr>
			<td>cotton tips</td>
			<td>Meditrade, Germany</td>
			<td>75481116</td>
			<td></td>
		</tr>
		<tr>
			<td>glass bowl for ultrasound gel</td>
			<td>ARC France, France</td>
			<td>H1149</td>
			<td></td>
		</tr>
		<tr>
			<td>water bowl</td>
			<td>W &#38; P Trading Co., USA</td>
			<td>B00K2P6PLQ</td>
			<td></td>
		</tr>
		<tr>
			<td>gauze sponges</td>
			<td>Fuhrmann, Germany</td>
			<td>960504</td>
			<td></td>
		</tr>
	</tbody>
</table>

utilizing high resolution ultrasound to monitor tumor onset and growth in genetically engineered pancreatic cancer models

The LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model represents an established and frequently used transgenic model to evaluate novel therapies in pancreatic cancer. Tumor onset is variable in the KPC model between 8 weeks and several months. Therefore, non-invasive imaging tools are required to screen for tumor onset and monitor for response to treatment. To address this issue, different approaches have emerged over the last years. High resolution ultrasound has major advantages such as non-invasiveness, fast session times and a high image resolution without radiation exposure. However, ultrasound in mice is not trivial and sufficient anatomical knowledge and practical skills are required to successfully perform high resolution ultrasound in preclinical pancreatic cancer models. With the following article, a detailed hands-on guide for abdominal ultrasound in murine models with a particular focus on endogenous pancreatic cancer models is presented. Furthermore, a summary of common mistakes and how to avoid them is provided.

Ultrasound imaging is a versatile and non-invasive technique that is used to address several issues in murine models of human diseases. Compared to all other imaging approaches major advantages are high-throughput, cost efficiency, short acquisition time and real-time imaging. However, this tool needs expertise to generate accurate, high quality images. Particularly in the case of unwanted artefacts at least some experience with ultrasound imaging in general is very helpful. In relation t...

Watch this Scientific Journal Video about Utilizing High Resolution Ultrasound to Monitor Tumor Onset and Growth in Genetically Engineered Pancreatic Cancer Models at JoVE.com

Utilizing High Resolution Ultrasound to Monitor Tumor Onset and Growth in Genetically Engineered Pancreatic Cancer Models

This article describes the utilization of high-resolution ultrasound in genetically engineered pancreatic cancer mice. The primary aim is to provide a detailed instruction for detection and evaluation of endogenous pancreatic tumors.

The LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre (KPC) mouse model represents an established and frequently used transgenic model to evaluate novel ...

There are various genetically engineered mouse models to study pancreatic cancer. The most commonly used model is the Kras, p53 mouse model that harbors an activating mutation in the Kras oncogene, and an inactivating mutation in the p53 tumor suppressor gene. Both mutations are conditionally activated by the Pdx-Cre promoter.This Kras, p53, Pdx-Cre mouse model, in short KPC model, develops endogenous pancreatic tumors between the age of two to six month. In preparation of your ultrasound procedure, the following equipment should be prepared and ready to use. For high resolution ultrasound, a stationary ultrasound device is used.The ultrasound procedure is conducted in general anesthesia using isoflurane evaporation. Once the mouse is under deep sedation, it is transferred to the green working stage. After the ultrasound procedure, the mouse should be placed in a pre-heated cage to accelerate recovery.Tumor development is highly variable in the KPC mouse model. To avoid unnecessary ultrasound screening procedures, we usually perform abdominal palpation weekly starting from the age of two months. Gently, palpate the mouse abdomen up and down to detect any pancreatic tumors.Keep in mind that hard feces may mimic abdominal tumor masses. After initiation of general anesthesia, in a separate induction chamber, the mouse is carefully placed onto the green and pre-heated working stage. During the ultrasound procedure, isoflurane is continuously supplied via the nose cone.Fix the trandsucer head at the top of your working stage by using the mounting system. Perform the foot-pinch test to make sure the mouse is under deep anesthesia. Afterwards, the mouse is fixed onto the working platform using medical strips.It is crucial to completely remove the abdominal fur prior to the ultrasound procedure, to avoid any artifacts. First, carefully shave off the mouse fur. Great care should be taken to avoid any superficial skin lacerations using the pet clipper.Second, apply a thin layer of the depilatory cream onto the shaved area. Completely remove the cream using moist tissues. Apply abundant ultrasound gel onto the mouse abdomen, and a thin layer of gel directly onto the ultrasound probe.Adjust the transducer onto the abdomen using soft pressure. Heavy compression of the mouse abdomen may lead to respiratory or circulatory impairment, and should be avoided. Scan up and down and adjust the frame of the working platform and the wheels for the x and y axis.Some tumors may only be visible by changing the initial position of the mouse. To correctly interpret B-mode ultrasound images, basic anatomical knowledge is required. In the KPC mouse model, pancreatic tumors can be detected in the head, body, or tail of the pancreas.The tumors usually demarcate as hypoechoic masses. Due to their desmoplastic features, these tumors are usually hard to compress by the ultrasound probe. Following the ultrasound, completely remove the ultrasound gel and gently place the mouse in the pre-heated recovery cage.Once you identified a tumor, scan up and down to get an impression of the total size, and measure the largest diameter by using the ultrasound caliper. For the exact volume calculation, we use the formula of an ellipsoid. After finishing the measurement of the first plane, either rotate the scan-head by 90 degree, in a longitudinal position, or turn the mouse to its side, to detect the tumor's longitudinal expansion.For the evaluation of novel therapeutic approaches, it is important to determine the initial tumor volume and the tumor growth kinetics during treatment. During pre-clinical trials, abdominal ultrasound can be repeated every three to four days to monitor tumor growth.

utilizing-high-resolution-ultrasound-to-monitor-tumor-onset-growth

Research

JoVE Journal

Cancer Research

10.6K vistas.  University Medical Center Goettingen. There are various genetically engineered mouse models to study pancreatic cancer. The most commonly used model is the Kras, p53 mouse model that harbors an activating mutation in the Kras oncogene, and an inactivating mutation in the p53 tumor suppressor gene. Both mutations are conditionally activated by the Pdx-Cre promoter.This Kras, p53, Pdx-Cre mouse model, in short KPC model, develops endogenous pancreatic tumors between the age of two to six month. In preparation of your ultraso...