This work was supported by the German Research foundation (WE 3548/4-1) and Roland-Ernst-Stiftung f&#252;r Gesundheitswesen (1/14).

The animal experiments presented here were independently reviewed and permitted by an institutional and a governmental Animal Care and Use Committee and were conducted according to Federation of Laboratory Animal Science Associations (FELASA) guidelines. All possible measures were taken to minimize suffering including anesthesia and analgesia or, if necessary, premature euthanasia.
1. Preparation of Cells and Organoids
NOTE: Use a volume of 20 &#181;L with 100,000 cells for each injection. Use basement membrane matrix (BMM) in order to prevent leakage and ensure standardized injection. In order to ensure reproducible results, conduct cell line authentication assays (e.g., via STR profiling) at regular intervals.
<ol>
	<li>Preparation of primary cell suspensions from fresh tissue 
	NOTE: Always work under sterile conditions. Immediate transfer of the freshly resected tissue from the operating room to the laboratory on ice is required to ensure high viability of the cells. 
	The patient&#39;s well-being and optimal treatment must always be the first priority. Therefore, tissue samples for research must be obtained in a manner that does not interfere with the subsequent pathological work-up and staging of the resected tumor. In most cases, it is therefore reasonable to have the samples for research obtained by a trained pathologist in order to ensure non-interference with the pathological diagnosis.
	<ol>
		<li>Immediately after sterile removal from the resected specimen (ideally ~1 cm3), place the tissue sample in a 50 mL tube pre-filled with 20-30 mL of phosphate-buffered saline (PBS). Store the tube on ice and transfer to the laboratory immediately.</li>
		<li>Put the tissue in a Petri dish and wash it twice with plenty of PBS to remove the remaining blood.</li>
		<li>Cut the tissue into small pieces (~ 2-4 mm) with a scalpel (e.g., with a #20 or #36 blade).</li>
		<li>Use the dissociator according to the manufacturer&#39;s instructions in order to further dissociate the tumor tissue to a single-cell suspension. Alternatively, use other protocols of enzymatic tumor digestion.</li>
		<li>Count the cells of the resulting single-cell suspension (e.g., in a coulter counter or a hemocytometer).</li>
		<li>Centrifuge (5 min at 1,500 x g) and wash the cell suspension twice with PBS.</li>
		<li>Resuspend the cells in BMM at a concentration of 5 x 106 cells/mL and keep them on ice.</li>
	</ol>
	</li>
	<li>Preparation of cell lines for injection
	<ol>
		<li>Grow all colorectal cancer cell lines under standard culturing conditions (37 &#176;C, 5% CO2) and prepare them at the day of surgery.</li>
		<li>Harvest the cells according to standard cell culture protocols, count the cells (e.g., in a coulter counter or a hemocytometer) and calculate the required amount for all injections depending on the numbers of animals to be injected.</li>
		<li>Prepare 3-5x of the actually needed volume to account for pipetting losses and the dead volume of the injection syringe.</li>
		<li>Centrifuge (5 min at 1,500 g) and wash the cell suspension twice with PBS.</li>
		<li>Resuspend the cells in BMM at a concentration of 5 x 106 cells/mL and keep them on ice.</li>
	</ol>
	</li>
	<li>Organoid preparation 
	NOTE: All 3D organoid cultures are grown under standard culturing conditions (37 &#176;C, 5% CO2). Detailed protocols for organoid culture have been published before.18,19,20 Similar to conventional cell lines, we recommend a volume of 20 &#181;L BMM with 100,000 cells per injection. The organoids are prepared at the day of surgery as follows:
	<ol>
		<li>Prepare the following medium (in the following referred to as DMEM/F12+++): Advanced Dulbecco&#39;s Modified Eagle&#39;s Medium (DMEM)/F12 + 1% HEPES (1M) + 1% Glutamine (200 mM) + 1% Penicillin/Streptomycin.</li>
		<li>Pre-fill 15 mL tubes with 1 mL DMEM/F12+++.</li>
		<li>Carefully aspirate the organoids from the surface of the culture plate and transfer the contents of 3 to 5 wells into one 15 mL tube.</li>
		<li>Carefully break the organoids up into smaller pieces by pipetting them up and down with an extended glass pipette.</li>
		<li>Add 5 mL DMEM/F12+++ to the tube, followed by centrifugation at 1,000 x g for 5 min.</li>
		<li>After centrifugation, remove the supernatant, resuspend the pellet in 600 &#181;L enzymatic dissociation buffer and transfer the suspension to one well of a 6-well plate.</li>
		<li>Incubate at 37 &#176;C for 1-5 min and then carefully pipet the suspension up and down in order to dissolve the organoids. 
		NOTE: Verify the digestion via microscope; it is complete when all cell clusters have been dissociated to single cells.</li>
		<li>Upon successful digestion, add 1.4 mL of DMEM/F12+++ to stop the digestion. Then transfer all wells of digested organoids to a 50 mL tube.</li>
		<li>Count the cells and calculate the required amount for all injections.</li>
		<li>Prepare 3 - 5x of the actually needed volume to account for pipetting losses and the dead volume of the injection syringe</li>
		<li>Centrifuge (5 min at 1,500 x g) and wash the cell suspension twice with PBS.</li>
		<li>Resuspended the cells in BMM to a concentration of 5 x 106 cells/mL and keep them on ice.</li>
	</ol>
	</li>
</ol>
2. Orthotopic Mouse Model
<ol>
	<li>Preparation of recipient animals for surgery 
	NOTE: Use 6-8 week-old NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NOD scid gamma, NSG) mice as recipients.21 NSG are among the most immunocompromised mice, lacking mature B, T and NK cells along with multiple other immune defects.21 They reliably grow tumors even if low cell numbers are injected and are highly prone to distant metastases. NSG mice are excellent breeders and can be kept in conventional specific pathogen free (SPF) units.
	<ol>
		<li>Prior to the first incision, inject 0.05 mg/kg of buprenorphine subcutaneously.</li>
		<li>Use sevoflurane at 3-3.5 vol% for general anesthesia. A loss of the toe pinch reflex indicates sufficient anesthesia.</li>
		<li>Cover the eyes of the anesthetized mice with ophthalmic ointment to avoid desiccation of the cornea.</li>
		<li>Restrain the mice in a supine position on a small table.</li>
		<li>Shave the abdomen with an electric shaver (depilatory cream can be used alternatively) and disinfect with at least 3 times clorhexidine/iodine and 70% alcohol alternatively.</li>
		<li>Cover the surgical field with sterile drapes. 
		NOTE: The use of perioperative antibiotics is optional and subject to institutional guidelines.</li>
	</ol>
	</li>
	<li>Midline laparotomy and exposure of the cecum
	<ol>
		<li>Use scissors (scalpels can be used alternatively) to make a small midline incision (3 - 5 mm) of the skin on the lower abdomen. Pick up the abdominal wall musculature with forceps and carefully incise it with scissors, thus opening the abdominal cavity.</li>
		<li>Identify and carefully exteriorize the cecum with atraumatic forceps. Position the blind ending pouch of the cecum on the abdomen pointing cranially.</li>
		<li>Once exteriorized, keep the cecum moist using warm saline swabs at all times.</li>
	</ol>
	</li>
	<li>Orthotopic injection, closure of the abdomen and postoperative recovery
	<ol>
		<li>For intracecal injection, use a standard 1 mL syringe with a 30 G cannula. Mount this syringe on a microinjection pump, which is in turn mounted on a micromanipulator.</li>
		<li>Carefully grasp the tip of the cecum with atraumatic forceps and gently smoothen it by stroking it downward with a second set of forceps moistened with warm saline.</li>
		<li>Position the cannula directly above the cecum.</li>
		<li>Perform the following steps under visual control with a binocular surgical microscope.</li>
		<li>Carefully grasp the cecum with two atraumatic forceps at both ends of the exteriorized part of the cecum, slightly stretch it and then slowly pull it over the cannula which is positioned parallel and directly above. It is crucial not to perforate the entire bowel wall (thus injecting the cells into the lumen) as well as not to perforate the serosa beyond the initial point of penetration, as this would lead to leakage and peritoneal dissemination.
		<ol>
			<li>Move the bowel towards the cannula, not the cannula towards the bowel. Hold and stretch the bowel between two forceps. The surgeon&#39;s hands must be resting on a surface in order to reduce tremor.</li>
		</ol>
		</li>
		<li>Inject the cells between the serosa (seen as very thin, translucent lining above the intramural blood vessels) and the muscularis. The cannula must therefore be visually placed above the blood vessels and underneath the thin translucent membrane.</li>
		<li>Use a foot switch to start the injection in order to reduce tremor while the cannula is inside the bowel wall.</li>
		<li>Once the cannula is in position, start the injection. Use a duration of 20 s, resulting in 1 &#181;L/s setting on the control unit of the pump. 
		NOTE: The injection into or near a damaged blood vessel leads to direct intravascular dissemination and distant metastasis and should therefore be avoided.</li>
		<li>After completion of the injection, carefully remove the cannula by pulling it backward.</li>
		<li>Place a dry swab under the cecum, and then thoroughly rinse the cecum with distilled water in order to lyse leaked cells and thus prevent artificial peritoneal dissemination.</li>
	</ol>
	</li>
	<li>Closure of the abdomen and postoperative recovery
	<ol>
		<li>After rinsing, gently return the cecum to the abdominal cavity.</li>
		<li>Close the abdominal wall with 6-0 rapidly absorbable running sutures.</li>
		<li>Close the skin with surgical wound clips.</li>
		<li>Place the mouse on a heating map set to 38 &#176;C until it has fully recovered from the anesthesia.</li>
		<li>Closely observe the postoperative condition of the mice for the following 48 h. In case of distress, treat with 0.05 mg/kg buprenorphine every 12 h.</li>
		<li>Monitor the mice at least once daily for signs of distress due to tumor growth.</li>
	</ol>
	</li>
</ol>
3. Isolation of Circulating Tumor Cells from Whole Blood Samples
NOTE: Obtain blood by transcutaneous cardiac puncture on anesthetized mice, followed by euthanasia. Ideally, 1,000 &#181;L of blood are drawn into a syringe prefilled with 100 &#181;L of an anticoagulant (Ethylenediaminetetraacetic acid (EDTA) or heparin). Use an anti-human-EpCAM (epithelial cell adhesion molecule) antibody to identify the CTCs. This works very well if human epithelial cell lines are used in the mouse model. For other appliances, different antibodies may be required.
<ol>
	<li>CTC enrichment:
	<ol>
		<li>Pre-fill 15 mL tubes with 5 mL density gradient medium and carefully transfer the blood into the 15 mL tube.</li>
		<li>Centrifuge (30 min at 300 x g without brake) and carefully remove the upper supernatant.</li>
		<li>Pour the rest into a new 15 mL tube and centrifuge (15 min, 300 x g with brake).</li>
		<li>Recover the interphase containing the mononuclear cells (discard the rest) and wash the cells twice with PBS.</li>
		<li>Resuspend the pellet in 200 &#181;L PBS/1% EDTA and add 4 &#181;L of EpCAM antibody. Incubate 20 min on ice in the dark.</li>
	</ol>
	</li>
	<li>Screening and picking
	<ol>
		<li>Prepare the following buffer (in the following referred to as picking buffer): PBS + 10% fetal calf serum (FCS) + 1% Penicillin/Streptomycin (1%) + 0.8% EDTA.</li>
		<li>Use a PAP pen to draw a ~1 cm circle in a 6 cm sterile Petri dish (prevents the fluid from dispersing in the dish), and pipet 700 &#181;L of picking buffer into this circle.</li>
		<li>Add 50 &#181;L of cell suspension to the 700 &#181;L picking buffer within the circle. Check the density of cells with the microscope. Split the sample into different dishes if it is too dense.</li>
		<li>Wait for the cells to settle down (~5 min).</li>
		<li>Screen the drop of cell suspension for stained (= EpCAM-positive) cells.</li>
		<li>Once a cell is found, pick the cell with the micromanipulator and put it in 50 &#181;L buffer depending on the intended downstream analysis (e.g., RNA extraction buffer or culturing medium).</li>
		<li>Depending on the intended downstream analyses, isolate EpCAM-negative cells and/or medium as negative controls.</li>
		<li>Proceed with downstream analyses (e.g., cell culture, PCR).</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

Despite their preclinically proven activity in subcutaneous mouse models, the great majority of novel compounds fail in clinical trials and never reach the clinic.11 This obvious insufficiency of subcutaneous mouse models to accurately simulate the biology and growth patterns of tumors has led to the development of orthotopic mouse models based on the injection of tumor cells directly into the original organ.
Orthotopic mouse models are able to simulate the biology and ...

Colorectal cancer (CRC) is one of the most common causes of cancer death in western countries.1 While the primary tumor can often be resected, the occurrence of distant metastases dramatically worsens the prognosis and often leads to death.2,3 The biological correlate of metastasis is circulating tumor cells (CTCs), which detach from the tumor, survive in circulation, attach to the epithelium in the target organ, invade the organ and ultimately outgrow to new lesions.4 Although CTCs are known to be of prognostic relevance,5,6,7,8,9 their biology is only partly understood as a result of their extreme rarity in CRC.10
Mouse models are a powerful tool to study various aspects of cancer biology. Classical, subcutaneous tumor models are produced by subcutaneous injection of tumor cells into recipient mice, which can be either immunocompetent (if syngeneic murine tumor cells are used) or immunodeficient. Subcutaneous tumor models are inexpensive and produce data fast; their end-point tumor growth can be easily and non-invasively measured. However, 88% of new compounds that have demonstrated antitumor activity in such models fail in clinical trials.11 This is in part due to interspecies differences between humans and mice; however, a large part of this failure is due to the low predictive value of subcutaneous mouse models.
Orthotopic mouse models, in which the tumor cells are injected into the organ of origin and thus grow in their original microenvironment, are therefore increasingly used in cancer research.11,12,13,14 Orthotopic models do not only simulate local tumor growth conditions; as a result of the anatomically correct site of tumor growth, orthotopic mouse models also allow realistic simulation of metastasis and are therefore used to study CTC biology8,15,16 or their response to different treatments in CRC.13,17
A major disadvantage of orthotopic mouse models is their technical complexity. Depending on the organ in which the cells are to be injected, the learning curve until the experimenter is able to induce reproducible tumors is rather long. This especially applies to colorectal cancer models, as the tumor cells need to be injected into the bowel wall, which often results in perforation, tumor cell leakage or endoluminal tumor cell loss. This article is intended to describe the method of cell preparation from primary tissue samples, 2D cell lines and 3D organoid culture and their injection into the cecum of mice. The technique described here leads to highly uniform tumors and, depending on the tumor biology of the cell line used for injection, reproducible formation of distant metastases and CTCs in the recipient mice.15

<table border="0" cellpadding="0" cellspacing="0" width="1294">
	<tbody>
		<tr height="25">
			<td height="25" style="height:25px;width:421px;">Cell culture Media and Components</td>
			<td style="width:297px;"></td>
			<td style="width:119px;"></td>
			<td style="width:457px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Advanced DMEM F12</td>
			<td style="width:297px;">Invitrogen</td>
			<td style="width:119px;">12634010</td>
			<td style="width:457px;">DMEM/ F12 +++ medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">HEPES (1 M)</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">15630056</td>
			<td style="width:457px;">DMEM/ F12 +++ medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Glutamax-I Supplement (200 mM)</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">35050038</td>
			<td style="width:457px;">DMEM/ F12 +++ medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Penicillin/Streptomycin (PenStrep)</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">15140122</td>
			<td style="width:457px;">DMEM/ F12 +++ medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">DMEM</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">61965026</td>
			<td>basic medium of 2D cell lines (DMEM/10%FCS)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Fetal Calf Serum (FCS)</td>
			<td style="width:297px;">BIOCHROM AG</td>
			<td style="width:119px;">S 0115</td>
			<td>basic medium of 2D cell lines (DMEM/10%FCS)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">TrypLE Express enzymatic dissociation buffer</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">12604021</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Matrigel basement membrane matrix (BMM, phenol red free)</td>
			<td style="width:297px;">CORNING B.V. Life Sciences</td>
			<td style="width:119px;">356231</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Dulbecco&#39;s Phosphate Buffered Saline</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">14190169</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Trypsin-EDTA (0,25%, Phenol-Red)</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">25200072</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">6-/48-well plates with lid</td>
			<td style="width:297px;">CORNING</td>
			<td style="width:119px;">3516/3548</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">cell culture flask 75cm&#178;, 250 mL</td>
			<td style="width:297px;">VWR International GmbH</td>
			<td style="width:119px;">734-2066</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">cell culture flask 150cm&#178;, 600 mL</td>
			<td style="width:297px;">Corning B.V. Life Sciences</td>
			<td style="width:119px;">355001</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:421px;">Eppendorf tubes 1,5 mL / 2 mL</td>
			<td style="width:297px;">Sarstedt AG &#38; Co.</td>
			<td style="width:119px;">72.706.400/ 72.695.400</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">15 ml, 50 ml centrifuge tubes</td>
			<td style="width:297px;">Greiner-Bio-One GmbH</td>
			<td style="width:119px;">188271/227270</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">TC10 Counting Slides (for TC20 Counting Machine)</td>
			<td style="width:297px;">Bio-Rad Laboratories GmbH</td>
			<td style="width:119px;">1450016</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:421px;">Pasteur pipettes (glass, 150 mm)</td>
			<td style="width:297px;">Fisher Scientific GmbH</td>
			<td style="width:119px;">11546963/ FB50251</td>
			<td>thinly pulled by using a bunsen burner</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">gentleMACS Dissociator</td>
			<td style="width:297px;">Miltenyi Biotec</td>
			<td>130-093-235</td>
			<td>for primary tumor tissue preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MACSmix Tube Rotator</td>
			<td style="width:297px;">Miltenyi Biotec</td>
			<td>130-090-753</td>
			<td>for primary tumor tissue preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">gentleMACS C Tubes</td>
			<td style="width:297px;">Miltenyi Biotec</td>
			<td>130-093-237</td>
			<td>for primary tumor tissue preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Human Tumor Dissociation Kit</td>
			<td style="width:297px;">Miltenyi Biotec</td>
			<td>130-095-929</td>
			<td>for primary tumor tissue preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Falcon 70&#181;m Cell Strainer</td>
			<td style="width:297px;">Corning B.V. Life Sciences</td>
			<td>352350</td>
			<td>for primary tumor tissue preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Name</td>
			<td style="width:297px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:421px;">Surgical Equipment</td>
			<td style="width:297px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Sevoflurane</td>
			<td style="width:297px;">AbbVie Germany GmbH &#38; Co. KG</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Medical oxygen</td>
			<td style="width:297px;">Air Liquide Medical GmbH</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Buprenorphine</td>
			<td style="width:297px;">Temgesic</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Bepanthen - opthalmic ointment</td>
			<td style="width:297px;">Bayer Vital GmbH</td>
			<td style="width:119px;">10047757</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Normal saline 0.9% (E154)</td>
			<td style="width:297px;">Serumwerk Bernburg AG</td>
			<td style="width:119px;">10013</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Aqua ad injectabilia</td>
			<td style="width:297px;">Braun</td>
			<td style="width:119px;">235144</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">1 mL Syringe (without dead volume) - Injekt-F SOLO</td>
			<td style="width:297px;">Braun/neoLab</td>
			<td style="width:119px;">194291661</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">30G injection needle</td>
			<td style="width:297px;">BECTON DICKINSON</td>
			<td style="width:119px;">304000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">cellulose swabs</td>
			<td style="width:297px;">Lohmann &#38; Rauscher Deutschland</td>
			<td style="width:119px;">13356</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Micro-Adson Forceps</td>
			<td style="width:297px;">FST - Fine Science Tools</td>
			<td style="width:119px;">11018-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Iris Scissor - ToughCut</td>
			<td style="width:297px;">FST - Fine Science Tools</td>
			<td style="width:119px;">14058-11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Olsen-Hegar Needle Holder</td>
			<td style="width:297px;">FST - Fine Science Tools</td>
			<td style="width:119px;">12002-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">AutoClip Kit</td>
			<td style="width:297px;">FST - Fine Science Tools</td>
			<td style="width:119px;">12020-00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">PDS Z1012H 6/0 C1 (surgical suture)</td>
			<td style="width:297px;">Johnson &#38; Johnson Medical GmbH</td>
			<td style="width:119px;">Z1012H</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:421px;">Table Top Research Anesthesia Machine w/O2 Flush and a Sevoflurane Vaporizer</td>
			<td style="width:297px;">Parkland Scientific</td>
			<td style="width:119px;">V3000PS/PK</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">UltraMicro Pump with Micro4 Controller</td>
			<td style="width:297px;">World Precision Instruments</td>
			<td style="width:119px;">UMP3-4</td>
			<td>equipment for highly controlled orthotopic injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Footswitch for SYS-Micro4 Controller</td>
			<td style="width:297px;">World Precision Instruments</td>
			<td style="width:119px;">15867</td>
			<td>equipment for highly controlled orthotopic injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Three-axis Manual Micromanipulator</td>
			<td style="width:297px;">World Precision Instruments</td>
			<td style="width:119px;">M325</td>
			<td>equipment for highly controlled orthotopic injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Magnetic Stand for Micromanipulator</td>
			<td style="width:297px;">World Precision Instruments</td>
			<td style="width:119px;">M10</td>
			<td>equipment for highly controlled orthotopic injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Steel Base Plate for M10 Magnetic Stand</td>
			<td style="width:297px;">World Precision Instruments</td>
			<td style="width:119px;">5479</td>
			<td>equipment for highly controlled orthotopic injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Hot Plate 062</td>
			<td style="width:297px;">Labotect</td>
			<td style="width:119px;">13854</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Isis - Hair shaver</td>
			<td style="width:297px;">AESCULAP - Braun</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Binocular Surgical Microscope</td>
			<td style="width:297px;">Parkland Scientific</td>
			<td style="width:119px;">VS-2Z</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Name</td>
			<td style="width:297px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:421px;">CTC isolation</td>
			<td style="width:297px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">EDTA</td>
			<td style="width:297px;">Roth</td>
			<td>8040.1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Density gradient medium &#8211; Ficoll</td>
			<td>StemCell - Lymphoprep</td>
			<td>7801</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:421px;">Alexa Fluor 488 anti-human CD326 (EpCAM) Antibody clone 9C4</td>
			<td>BioLegend</td>
			<td>324210</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:421px;">Alexa Fluor 488 anti-mouse CD326 (EpCAM) Antibody clone G8.8</td>
			<td>BioLegend</td>
			<td style="width:119px;">118210</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Petri Dish, &#248; 60 x 15 mm, 21 cm&#178;, Vent</td>
			<td>Greiner bio-one</td>
			<td>628102</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fluorescence Cell Culture Microscope</td>
			<td style="width:297px;">Leica</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Transferman 4r Micromanipulator</td>
			<td style="width:297px;">Eppendorf</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">CellTram Air</td>
			<td style="width:297px;">Eppendorf</td>
			<td style="width:119px;"></td>
			<td style="width:457px;">aspiration pump connected to the micromanipulator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dmz Universal Microelectrode Puller</td>
			<td style="width:297px;">Dagan Corporation</td>
			<td style="width:119px;"></td>
			<td>required for the manufacturing of micro capillaries for single cell aspiration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Prism Glass Capillaries</td>
			<td style="width:297px;">Dagan Corporation</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">PAP pen</td>
			<td style="width:297px;">Abcam</td>
			<td style="width:119px;">ab2601</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Dulbecco&#39;s Phosphate Buffered Saline</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">14190169</td>
			<td>picking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Fetal Calf Serum (FCS)</td>
			<td style="width:297px;">BIOCHROM AG</td>
			<td style="width:119px;">S 0115</td>
			<td>picking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Penicillin/Streptomycin (PenStrep)</td>
			<td style="width:297px;">Life Technologies GmbH</td>
			<td style="width:119px;">15140122</td>
			<td>picking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">EDTA</td>
			<td style="width:297px;">Roth</td>
			<td>8040.1</td>
			<td>picking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Name</td>
			<td style="width:297px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:421px;">Immunohistochemistry</td>
			<td style="width:297px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">Purified anti-human CD326 (EpCAM) antibody clone 9C4</td>
			<td>BioLegend</td>
			<td style="width:119px;">324201</td>
			<td>EpCAM immunohistochemistry (cf, fig 2C)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:421px;">HRP rabbit anti-mouse IgG</td>
			<td style="width:297px;">Abcam</td>
			<td style="width:119px;">ab97046</td>
			<td>EpCAM immunohistochemistry (cf, fig 2C)</td>
		</tr>
	</tbody>
</table>

isolation of circulating tumor cells in an orthotopic mouse model of colorectal cancer

Despite the advantages of easy applicability and cost-effectiveness, subcutaneous mouse models have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Orthotopic mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in hollow organs such as the large bowel. In order to produce uniform tumors which reliably grow and metastasize, standardized techniques of tumor cell preparation and injection are critical. 
We have developed an orthotopic mouse model of colorectal cancer (CRC) which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor cells from either primary tumors, 2-dimensional (2D) cell lines or 3-dimensional (3D) organoids are injected into the cecum and, depending on the metastatic potential of the injected tumor cells, form highly metastatic tumors. In addition, CTCs can be found regularly. We here describe the technique of tumor cell preparation from both 2D cell lines and 3D organoids as well as primary tumor tissue, the surgical and injection techniques as well as the isolation of CTCs from the tumor-bearing mice, and present tips for troubleshooting.

The successful and reproducible generation of colorectal tumors in this model critically depends on accurate injection of the cells without spillage or leakage. If this is achieved, this model is extremely reliable and very rarely results in artificial peritoneal dissemination. The growth kinetics of the tumors as well as their dissemination patterns depend on the biology of the used organoids and cells.15 While HCT116 cells reliably metastasize to the liver in thi...

Watch this Scientific Journal Video about Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer at JoVE.com

Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer

We describe the establishment of orthotopic colorectal tumors via injection of tumor cells or organoids into the cecum of mice and the subsequent isolation of circulating tumor cells (CTCs) from this model.

Despite the advantages of easy applicability and cost-effectiveness, subcutaneous mouse models have severe limitations and do not accurately simulate ...

isolation-circulating-tumor-cells-an-orthotopic-mouse-model

Research

JoVE Journal

Cancer Research

9.9K Views.  Technische Universität Dresden. We describe the establishment of orthotopic colorectal tumors via injection of tumor cells or organoids into the cecum of mice and the subsequent isolation of circulating tumor cells (CTCs) from this model. 

Video: Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer

Fluorescent Orthotopic Mouse Model of Pancreatic Cancer

Pancreatic cancer remains one of the cancers for which survival has not improved substantially in the last few decades. Only 7% of diagnosed patients will survive longer than five years. In order to understand and mimic the microenvironment of pancreatic tumors, we utilized a murine orthotopic model of pancreatic cancer that allows non-invasive imaging of tumor progression in real time. Pancreatic cancer cells expressing green fluorescent protein (PANC-1 GFP) were suspended in basement membrane matrix, high concentration, (e.g., Matrigel HC) with serum-free media and then injected into the tail of the pancreas via laparotomy. The cell suspension in the high concentration basement membrane matrix becomes a gel-like substance once it reaches room temperature; therefore, it gels when it comes in contact with the pancreas, creating a seal at the injection site and preventing any cell leakage. Tumor growth and metastasis to other organs are monitored in live animals by using fluorescence. It is critical to use the appropriate filters for excitation and emission of GFP. The steps for the orthotopic implantation are detailed in this article so researchers can easily replicate the procedure in nude mice. The main steps of this protocol are preparation of the cell suspension, surgical implantation, and whole body fluorescent in vivo imaging. This orthotopic model is designed to investigate the efficacy of novel therapeutics on primary and metastatic tumors.

A procedure to implant green fluorescent protein-expressing pancreatic cancer cells (PANC-1 GFP) orthotopically into the pancreas of Balb-c Ola Hsd-Fox1nu mice to assess tumor progression and metastasis is presented here.

Pancreatic cancer remains one of the cancers for which survival has not improved substantially in the last few decades. Only 7% of diagnosed patients will ...

Murine Experimental Model of Original Tumor Development and Peritoneal Metastasis via Orthotopic Inoculation with Ovarian Carcinoma Cells

Epithelial ovarian carcinoma (EOC) is associated with a poor prognosis because it shows peritoneal dissemination. To improve the prognosis, it is important to control peritoneal dissemination. However, it is still unclear how tumor cells detach from primary lesions and attach to the mesothelium. The establishment of an appropriate animal model is needed to gain an understanding of the mechanism of peritoneal dissemination in vivo. In the current study, we introduce the process from the local injection of EOC cells into the murine ovarian surface to the development of metastasis, including the peritoneum and distant organs. Female nude mice (BALB/c nu/nu) at 8 weeks of age were used. Under a microscopic field of view, EOC cells (1 x 105 cells/&#181;l of medium-extracellular matrix (ECM)-based hydrogel/unilateral ovary/mouse) were injected into murine ovaries through a retroperitoneal approach from the dorsal flank. This proposed method is a less invasive procedure for the mouse and minimizes damage to the ovary. Here, we describe the methodological steps in the development of the original and metastatic tumor formation of EOC.

Murine Experimental Model of Original Tumor Development and Peritoneal Metastasis via Orthotopic Inoculation with Ovarian Carcinoma Cells

To clarify the multistep process of peritoneal dissemination of ovarian carcinoma, the current study presents a murine experimental model of original tumor development and peritoneal metastasis via orthotopic inoculation with these tumor cells.

Epithelial ovarian carcinoma (EOC) is associated with a poor prognosis because it shows peritoneal dissemination. To improve the prognosis, it is ...

Capture and Release of Viable Circulating Tumor Cells from Blood

We demonstrate a method for size based capture of viable circulating tumor cell (CTC) from whole blood, along with the release of these cells from chip for downstream analysis and/or culture. The strategy employs the use of a novel Parylene C membrane slot pore microfilter to capture CTC and a coating of poly (N-iso-propylacrylamide) (PIPAAm) for thermoresponsive viable release of the captured CTC. The capture of live cells is enabled by leveraging the design of a slot pore geometry with specific dimensions to reduce the shear stress typically associated with the filtration process. While the microfilter exhibits a high capture efficiency, the release of these cells is non-trivial. Typically, only a small percentage of cells are released when techniques such as reverse flow or cell scraping are used. The strong adhesion of these epithelial cancer cells to the Parylene C membrane is attributable to non-specific electrostatic interaction. To counteract this effect, we employed the use of PIPAAm coating and exploited its thermal responsive interfacial properties to release the cells from the filter. Blood is first filtered at room temperature. Below 32 &#176;C, PIPAAm is hydrophilic. Thereafter, the filter is placed in either culture media or a buffer maintained at 37 &#176;C, which results in the PIPAAm turning hydrophobic, and subsequently releasing the electrostatically bound cells.

A protocol to utilize a poly(N-iso-propylacrylamide) (PIPAAm) coated microfilter for effective capture and thermoresponsive release of viable circulating tumor cells (CTC) is presented. This method allows capture of CTC from patients&#39; blood and subsequent release of viable CTC for downstream off-chip culture, analyses and characterization.

We demonstrate a method for size based capture of viable circulating tumor cell (CTC) from whole blood, along with the release of these cells from chip ...

A Murine Orthotopic Bladder Tumor Model and Tumor Detection System

This protocol describes the generation of bladder tumors in female C57BL/6J mice using the murine bladder cancer cell line MB49, which has been modified to secrete human Prostate Specific Antigen (PSA), and the procedure for the confirmation of tumor implantation. In brief, mice are anesthetized using injectable drugs and are made to lay in the dorsal position. Urine is vacated from the bladder and 50 &#181;L of poly-L-lysine (PLL) is slowly instilled at a rate of 10 &#181;L/20 s using a 24 G IV catheter. It is left in the bladder for 20 min by stoppering the catheter. The catheter is removed and PLL is vacated by gentle pressure on the bladder. This is followed by instillation of the murine bladder cancer cell line (1 x 105 cells/50 &#181;L) at a rate of 10 &#181;L/20 s. The catheter is stoppered to prevent premature evacuation. After 1 h, the mice are revived with a reversal drug, and the bladder is vacated. The slow instillation rate is important, as it reduces vesico-ureteral reflux, which can cause tumors to occur in the upper urinary tract and in the kidneys. The cell line should be well re-suspended to reduce clumping of cells, as this can lead to uneven tumor sizes after implantation.
This technique induces tumors with high efficiency. Tumor growth is monitored by urinary PSA secretion. PSA marker monitoring is more reliable than ultrasound or fluorescence imaging for the detection of the presence of tumors in the bladder. Tumors in mice generally reach a maximum size that negatively impacts health by about 3 - 4 weeks if left untreated. By monitoring tumor growth, it is possible to differentiate mice that were cured from those that were not successfully implanted with tumors. With only end-point analysis, the latter may be mistakenly assumed to have been cured by therapy.

This protocol describes the generation of murine orthotopic bladder tumors in female C57BL/6J mice and the monitoring of tumor growth.

This protocol describes the generation of bladder tumors in female C57BL/6J mice using the murine bladder cancer cell line MB49, which has been modified ...

A Genetically Engineered Mouse Model of Sporadic Colorectal Cancer

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Genetically engineered mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in large organs such as the colon in which only a single tumor is desired.
As a result, an immunocompetent, genetically engineered mouse model of colorectal cancer was developed which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor development is initiated by surgical, segmental infection of the distal colon with adeno-cre virus in compound conditionally mutant mice. The tumors can be easily detected and monitored via colonoscopy. We here describe the surgical technique of segmental adeno-cre infection of the colon, the surveillance of the tumor via high-resolution colonoscopy and present the resulting colorectal tumors.

A protocol for the establishment of a genetically engineered mouse model of colorectal cancer by segmental adeno-cre infection and its surveillance via high-resolution colonoscopy is presented.

Despite the advantages of easy applicability and cost-effectiveness, colorectal cancer mouse models based on tumor cell injection have severe limitations ...

Isolation of Human Endothelial Cells from Normal Colon and Colorectal Carcinoma - An Improved Protocol

Primary cells isolated from human carcinomas are valuable tools to identify pathogenic mechanisms contributing to disease development and progression. In particular, endothelial cells (EC) constituting the inner surface of vessels, directly participate in oxygen delivery, nutrient supply, and removal of waste products to and from tumors, and are thereby prominently involved in the constitution of the tumor microenvironment (TME). Tumor endothelial cells (TECs) can be used as cellular biosensors of the intratumoral microenvironment established by communication between tumor and stromal cells. TECs also serve as targets of therapy. Accordingly, in culture these cells allow studies on mechanisms of response or resistance to anti-angiogenic treatment. Recently, it was found that TECs isolated from human colorectal carcinoma (CRC) exhibit memory-like effects based on the specific TME they were derived from. Moreover, these TECs actively contribute to the establishment of a specific TME by the secretion of different factors. For example, TECs in a prognostically favorable Th1-TME secrete the anti-angiogenic tumor-suppressive factor secreted protein, acidic and rich in cysteine-like 1 (SPARCL1). SPARCL1 regulates vessel homeostasis and inhibits tumor cell proliferation and migration. Hence, cultures of pure, viable TECs isolated from human solid tumors are a valuable tool for functional studies on the role of the vascular system in tumorigenesis. Here, a new up-to-date protocol for the isolation of primary EC from the normal colon as well as CRC is described. The technique is based on mechanical and enzymatic tissue digestion, immunolabeling, and fluorescence activated cell sorting (FACS)-sorting of triple-positive cells (CD31, VE-cadherin, CD105). With this protocol, viable TEC or normal endothelial cell (NEC) cultures could be isolated from colon tissues with a success rate of 62.12% when subjected to FACS-sorting (41 pure EC cultures from 66 tissue samples). Accordingly, this protocol provides a robust approach to isolate human EC cultures from normal colon and CRC.

Tumor endothelial cells are important determinants of the tumor microenvironment and the course of the disease. Here, a protocol for the isolation of pure and viable endothelial cells from human colorectal carcinoma and normal colon to be used in drug testing and pathogenesis research is described.

Primary cells isolated from human carcinomas are valuable tools to identify pathogenic mechanisms contributing to disease development and progression. In ...

Detection of a Circulating MicroRNA Custom Panel in Patients with Metastatic Colorectal Cancer

There is increasing interest in liquid biopsy for cancer diagnosis, prognosis and therapeutic monitoring, creating the need for reliable and useful biomarkers for clinical practice. Here, we present a protocol to extract, reverse transcribe and evaluate the expression levels of circulating miRNAs from plasma samples of patients with colorectal cancer (CRC). microRNAs (miRNAs) are a class of non-coding RNAs of 18-25 nucleotides in length that regulate the expression of target genes at the translational level and play an important role, including that of pro- and anti-angiogenic function, in the physiopathology of various organs. miRNAs are stable in biological fluids such as serum and plasma, which renders them ideal circulating biomarkers for cancer diagnosis, prognosis and treatment decision-making and monitoring. Circulating miRNA extraction was performed using a rapid and effective method that involves both organic and column-based methodologies. For miRNA retrotranscription, we used a multi-step procedure that considers polyadenylation at 3&#39; and the ligation of an adapter at 5&#39; of the mature miRNAs, followed by random miRNA pre-amplification. We selected a 24-miRNA custom panel to be tested by quantitative real-time polymerase chain reaction (qRT-PCR) and spotted the miRNA probes on array custom plates. We performed qRT-PCR plate runs on a real-time PCR System. Housekeeping miRNAs for normalization were selected using GeNorm software (v. 3.2). Data were analyzed using Expression suite software (v 1.1) and statistical analyses were performed. The method proved to be reliable and technically robust and could be useful to evaluate biomarker levels in liquid samples such as plasma and/or serum.

We present a protocol to evaluate the expression levels of circulating microRNA (miRNAs) in plasma samples from cancer patients. In particular, we used a commercially available kit for circulating miRNA extraction and reverse transcription. Finally, we analyzed a panel of 24 selected miRNAs using real-time pre-spotted probe custom plates.

There is increasing interest in liquid biopsy for cancer diagnosis, prognosis and therapeutic monitoring, creating the need for reliable and useful ...

Micromanipulation of Circulating Tumor Cells for Downstream Molecular Analysis and Metastatic Potential Assessment

Blood-borne metastasis accounts for&#160;most cancer-related deaths and involves circulating tumor cells (CTCs) that are successful in establishing new tumors at distant sites. CTCs are found in the bloodstream of patients as single cells (single CTCs) or as multicellular aggregates (CTC clusters and CTC-white blood cell clusters), with the latter displaying a higher metastatic ability. Beyond enumeration, phenotypic and molecular analysis is extraordinarily important to dissect CTC biology and to identify actionable vulnerabilities. Here, we provide a detailed description of a workflow that includes CTC immunostaining and micromanipulation, ex vivo culture to assess&#160;proliferative and survival capabilities of individual cells, and in vivo metastasis-formation assays. Additionally, we provide a protocol to achieve the dissociation of CTC clusters into individual cells and the investigation of intra-cluster heterogeneity. With these approaches, for instance, we precisely quantify survival and proliferative potential of single CTCs and individual cells within CTC clusters, leading us to the observation that cells within clusters display better survival and proliferation in ex vivo cultures compared to single CTCs. Overall, our workflow offers a platform to dissect the characteristics of CTCs at the single cell level, aiming towards the identification of metastasis-relevant pathways and a better understanding of CTC biology.

Here, we present an integrated workflow to identify phenotypic and molecular features that characterize circulating tumor cells (CTCs). We combine live immunostaining and robotic micromanipulation of single and clustered CTCs with single cell-based techniques for downstream analysis and assessment of metastasis-seeding ability.

Blood-borne metastasis accounts for&#160;most cancer-related deaths and involves circulating tumor cells (CTCs) that are successful in establishing new ...

Culture, Manipulation, and Orthotopic Transplantation of Mouse Bladder Tumor Organoids

The development of advanced tumor models has long been encouraged because current cancer models have shown limitations such as lack of three-dimensional (3D) tumor architecture and low relevance to human cancer. Researchers have recently developed a 3D in vitro cancer model referred to as tumor organoids that can mimic the characteristics of a native tumor in a culture dish. Here, experimental procedures are described in detail for the establishment of bladder tumor organoids from a carcinogen-induced murine bladder tumor, including culture, passage, and maintenance of the resulting 3D tumor organoids in vitro. In addition, protocols to manipulate the established bladder tumor organoid lines for genetic engineering using lentivirus-mediated transduction are described, including optimized conditions for the efficient introduction of new genetic elements into tumor organoids. Finally, the procedure for orthotopic transplantation of bladder tumor organoids into the wall of the murine bladder for further analysis is laid out. The methods described in this article can facilitate the establishment of an in vitro model for bladder cancer for the development of better therapeutic options.

This protocol provides detailed experimental steps to establish a three-dimensional in vitro culture of bladder tumor organoids derived from carcinogen-induced murine bladder cancer. Culture methods including passaging, genetic engineering, and orthotopic transplantation of tumor organoids are described.

The development of advanced tumor models has long been encouraged because current cancer models have shown limitations such as lack of three-dimensional ...

Ultrasound-Guided Orthotopic Implantation of Murine Pancreatic Ductal Adenocarcinoma

The recent success of immune checkpoint blockade in melanoma and lung adenocarcinoma has galvanized the field of immuno-oncology as well as revealed the limitations of current treatments, as the majority of patients do not respond to immunotherapy. Development of accurate preclinical models to quickly identify novel and effective therapeutic combinations are critical to address this unmet clinical need. Pancreatic ductal adenocarcinoma (PDA) is a canonical example of an immune checkpoint blockade resistant tumor with only 2% of patients responding to immunotherapy. The genetically engineered KrasG12D+/-;Trp53R172H+/-;Pdx-1 Cre (KPC) mouse model of PDA recapitulates human disease and is a valuable tool for assessing therapies for immunotherapy resistant in the preclinical setting, but time to tumor onset is highly variable. Surgical orthotopic tumor implantation models of PDA maintain the immunobiological hallmarks of the KPC tissue-specific tumor microenvironment (TME) but require a time-intensive procedure and introduce aberrant inflammation. Here, we use an ultrasound-guided orthotopic tumor implantation model (UG-OTIM) to non-invasively inject KPC-derived PDA cell lines directly into the mouse pancreas. UG-OTIM tumors grow in the endogenous tissue site, faithfully recapitulate histological features of the PDA TME, and reach enrollment-sized tumors for preclinical studies by four weeks after injection with minimal seeding on the peritoneal wall. The UG-OTIM system described here is a rapid and reproducible tumor model that may allow for high throughput analysis of novel therapeutic combinations in the murine PDA TME.

We describe a protocol for the ultrasound guided implantation of murine-derived pancreatic ductal adenocarcinoma cell lines directly into the native tumor site. This approach resulted in pancreatic tumors detectable by ultrasound scanning within 2-4 weeks of injection, and significantly reduced the proportion tumor cell seeding on the peritoneal wall as compared to surgical orthotopic implantation.

The recent success of immune checkpoint blockade in melanoma and lung adenocarcinoma has galvanized the field of immuno-oncology as well as revealed the ...