We thank Harold Varmus, Brian C. Lewis, Douglas Hanahan, Danny Huang, Sharon Pang, Megan Wong, and Manasi M. Godbole. Y.C.N.D. is supported by DOD grant W81XWH-16-1-0619 and NIH grant 1R01CA204916.

Ethics Statement:Experiments on animals were performed in accordance with the guidelines and regulations set forth by the Institute for Animal Care and Use Committee of Weill Cornell Medicine.
1. Choice of Avian Retroviral Vectors (RCASBP(A)-based or RCANBP(A)-based)
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	<li>Vectors was derived from Rous sarcoma virus11. Avian retroviral vectors can deliver cDNAs (&#8804;2.5 kb), short hairpin RNAs (shRNAs), microRNAs (miRNAs), and other no...

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R., Sambrook, J., Sambrook, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Molecular cloning: a laboratory manual. , (2012).</li><li>Du, Y. C., Lewis, B. C., Hanahan, D., Varmus, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+tumor+progression+factors+by+somatic+gene+transfer+into+a+mouse+model:+Bcl-xL+promotes+islet+tumor+cell+invasion.">Assessing tumor progression factors by somatic gene transfer into a mouse model: Bcl-xL promotes islet tumor cell invasion.</a> PLoS Biol. 5 (10), 2255-2269 (2007).</li><li>Du, Y. C., Chou, C. K., Klimstra, D. S., Varmus, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Receptor+for+hyaluronan-mediated+motility+isoform+B+promotes+liver+metastasis+in+a+mouse+model+of+multistep+tumorigenesis+and+a+tail+vein+assay+for+metastasis.">Receptor for hyaluronan-mediated motility isoform B promotes liver metastasis in a mouse model of multistep tumorigenesis and a tail vein assay for metastasis.</a> Proc Natl Acad Sci USA. 108 (40), 16753-16758 (2011).</li><li>Guernet, A., Grumolato, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CRISPR/Cas9+editing+of+the+genome+for+cancer+modeling.">CRISPR/Cas9 editing of the genome for cancer modeling.</a> Methods. , (2017).</li></ol>

In this study, we described a powerful mouse model, RIP-Tag; RIP-tva, to achieve somatic gene delivery via avian retroviruses for the identification and characterization of metastatic factors. Although RIP-Tag; RIP-tva mice develop pancreatic neuroendocrine tumors, metastatic factors identified in this mouse model may also promote metastasis of other cancer types.
Our approach has the advantage of introducing somatic genetic changes specifically into premalignant lesions of p...

Most cancers arise from somatic mutations 1. Conventional genetically engineered mouse models (GEMM) have provided significant insights into the contribution of specific genetic alterations to tumorigenesis 2. However, they have several limitations. The major drawback of these models is that they do not replicate the sporadic nature of tumor formation in humans, in which only some cells within a tissue acquire genetic alterations. The mutations in transgenic and knockout mice are also germline with potential to affect development. Moreover, generating these mouse models is expensive and time-consuming.
Metastasis is a significant issue in the field of cancer. Modeling metastasis has been difficult in GEMM. Spontaneous metastasis is rare in the mouse. Penetrance is variable and latency is long in GEMM of metastasis 3. Experimental metastasis models employ direct injection of cells into the circulation of mice, so the early steps in the metastatic cascade are eliminated.
To overcome some of the above limitations in studying metastatic factors in mouse models, we have developed a bitransgenic mouse model, RIP-Tag; RIP-tva4. The strategy is based on combining the use of a highly-synchronized tumor progression mouse model, RIP-Tag 5, and the receptor for subgroup-A avian leukosis virus, tva 6,7. This RIP-Tag; RIP-tvamouse model allows genes to be introduced somatically into a single bitransgenic mouse strain. With the SV40 T antigen suppressing the tumor suppressive functions of Rb and p53, mice develop pancreatic neuroendocrine tumors in a similar fashion to human tumorigenesis, with stages including hyperplasia, angiogenesis, adenoma, and invasive carcinoma.This RIP-Tag model has been very instructive for our understanding of hallmarks of cancer, not limited to pancreatic neuroendocrine tumors. It has also been used in preclinical trials 8.
We present a protocol for somatic gene transfer through injection of avian retroviruses intracardiacally into RIP-Tag; RIP-tva mice. Successful infection with RCASBP-derived avian retroviruses requires actively proliferating target cells. Therefore, we chose RIP-Tag; RIP-tva mice at 7 weeks of age, when hyperplasia develops in about 50% of the pancreatic islets. Left ventricular intracardiac injection of high titer viruses is required to achieve an infection efficiency of 10-20% 4. This delivery method reduces the significant dilution of viral particles within circulation before viruses reach pancreatic islets.
Using this approach, we have previously demonstrated that Bcl-xL promotes cancer metastasis independent of its anti-apoptotic function 4,9. This anti-apoptotic-independent metastatic function was not observed when Bcl-xL was expressed via a transgene in all pancreatic &#946; cells throughout tumorigenic ontogeny in the RIP-Tag; RIP-Bcl-xL mouse model 10. Therefore, our mouse model offers a unique opportunity to identify and characterize genes&#39; functions when expressed at a later stage of tumorigenesis. Because 2-4% of islets develop into tumors in the RIP-Tag; RIP-tva bitransgenic mice without viral infection and not all the premalignant lesions are infected with the RCASBP-derived avian retroviruses, only the factors that confer a selective advantage over the natural course of tumorigenesis can be identified. In particular, metastatic factors will be most easily recognized by this method, because metastasis to pancreatic lymph nodes or other organs does not normally occur in RIP-Tag; RIP-tva mice.

<table border="0" cellpadding="0" cellspacing="0" width="747">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">RCASBP-Y DV plasmid</td>
			<td style="width:123px;">Addgene</td>
			<td style="width:119px;">11478</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RCAS-RNAi plasmid</td>
			<td style="width:123px;">Addgene</td>
			<td style="width:119px;">15182</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">DMEM</td>
			<td style="width:123px;">Corning</td>
			<td>10-013-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">fetal bovine serum</td>
			<td>Atlanta Biologicals</td>
			<td>25-005-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">L-glutamine, 100x</td>
			<td style="width:123px;">Corning</td>
			<td>25-005-CI</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin-Streptomycin solution, 100x</td>
			<td style="width:123px;">Corning</td>
			<td>30-002-CI</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">PBS-/-, 1X</td>
			<td style="width:123px;">Corning</td>
			<td>21-040-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Superfect</td>
			<td>Qiagen</td>
			<td>301305</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Polyallomer centrifuge tube</td>
			<td>Beckman Coulter</td>
			<td>326823</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:339px;">0.45 mm Nalgene 
			Syringe Filters with PES Membrane</td>
			<td style="width:123px;">Thermo Scientific</td>
			<td style="width:119px;">194-2545</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Insulin Syringes&#160;</td>
			<td style="width:123px;">BD</td>
			<td>329461</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">synaptophysin</td>
			<td style="width:123px;">Vector Laboratories</td>
			<td>VP-S284</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">VECTASTAIN Elite ABC HRP Kit (Peroxidase, Rabbit IgG)&#160;</td>
			<td style="width:123px;">Vector Laboratories</td>
			<td>PK-6101</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">AmpliTaq DNA Polymerase with Buffer II</td>
			<td>Life Technologies</td>
			<td>N8080153</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MyTaq DNA Polymerase</td>
			<td>Bioline</td>
			<td>BIO-21106</td>
			<td></td>
		</tr>
	</tbody>
</table>

identification and characterization of metastatic factors by gene transfer into the novel rip-tag; rip-tva murine model

Metastatic cancer accounts for 90% of deaths in patients with solid tumors. There is an urgent need to better understand the drivers of cancer metastasis and to identify novel therapeutic targets. To investigate molecular events that drive the progression from primary cancer to metastasis, we have developed a bitransgenic mouse model, RIP-Tag; RIP-tva. In this mouse model, the rat insulin promoter (RIP) drives the expression of the SV40 T antigen (Tag) and the receptor for subgroup A avian leukosis virus (tva) in pancreatic &#946; cells. The mice develop pancreatic neuroendocrine tumors with 100% penetrance through well-defined stages that are similar to human tumorigenesis, with stages including hyperplasia, angiogenesis, adenoma, and invasive carcinoma. Because RIP-Tag; RIP-tva mice do not develop metastatic disease, genetic alterations that promote metastasis can be identified easily. Somatic gene transfer into tva-expressing, proliferating pancreatic &#946; premalignant lesions is achieved through intracardiac injection of avian retroviruses harboring the desired genetic alteration. A titer of &#62;1 x 108 infectious units per ml is considered appropriate for in vivo infection. In addition, avian retroviruses can infect cell lines derived from tumors in RIP-Tag; RIP-tva mice with high efficiency. The cell lines can also be used to characterize the metastatic factors. Here we demonstrate how to utilize this mouse model and cell lines to assess the functions of candidate genes in tumor metastasis.

The in vivo and in vitro infection rate of RIP-Tag; RIP-tva tumor cells by RCASBP-based viruses are ~20% and ~80% respectively 20. In the RIP-Tag; RIP-tva mouse model, approximately 4% of the 400 pancreatic islets in each mouse will naturally develop into tumors 20; therefore there is sufficient amount of tumor cells in each mouse for histological and phenotypic analysis of the potential effect of the gene...

Watch this Scientific Journal Video about Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model at JoVE.com

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

We present a protocol to demonstrate a novel somatic gene transfer system utilizing RIP-Tag; RIP-tva mouse model to study the function of genes in metastasis. The avian retroviruses are delivered intracardiacally to ensure gene transfer into pre-malignant, noninvasive lesions of pancreatic &#946; cells in adult mice.

Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

Metastatic cancer accounts for 90% of deaths in patients with solid tumors. There is an urgent need to better understand the drivers of cancer metastasis ...

The overall goal of this procedure is to identify and characterize metastatic factors by gene transfer into the Novel RIP-Tag;RIP-tva mouse model. This method can help answer key questions in the cancer metastasis field such as identifying the drivers and the Novel therapeutic targets. The main advantage of this mouse model of cancer is to identify metastatic factors by somatic gene transfer into pancreatic beta cell precursor legions.Begin by harvesting one 15 centimeter dish of virus producing DF1 cells per mouse to be infected. First, collect the medium from the confluent 15 centimeter dishes. Then remove cell debris by low speed centrifugation in a pre-chilled centrifuge for 10 minutes at 1650 times G and four degrees celsius.Next, transfer the viral supernatant to polyallomer ultracentrifuge tubes. Spin in an ultracentrifuge for 1.5 hours at 9540 times G and four degrees celsius. Remove as much supernatant from the ultracentrifuge tubes as possible.Then add PBS to the ultracentrifuge tube to make the final 100 microliter viral suspension per 15 centimeter dish. Cover the tubes with laboratory film and re-suspend the invisible viral pellet by vortexing for two minutes at medium speed. Then rock the ultracentrifuge tubes at four degrees celsius for one hour or overnight.After the incubation, transfer the viral suspension to a microcentrifuge tube and proceed to titer the virus. Begin the titering procedure by ensuring the DF1 cells seated into 12 well tissue culture plates have reached 30%confluency. One twelve well plate is needed for each viral titer determination.Begin a tenfold serial dilution of the viral supernatants by first mixing five microliters of viral supernatant with 495 microliters of growth medium in a microcentrifuge tube to make a ten to the second dilution. Vortex briefly for a few seconds. Then transfer 40 microliters of the ten to the second dilution to 360 microliters of growth medium in a microcentrifuge tube for the ten to the third dilution.Vortex briefly for a few seconds. Continue this process to dilute to ten to the fourth and ten to the fifth. Next aliquot 2.25 milliliters of growth medium into each of five six milliliter polystyrene tubes.And label them ten to the sixth, ten to the seventh, ten to the eighth, ten to the ninth, and ten to the tenth respectively. Mix 0.25 milliliters of the ten to the fifth dilution with 2.25 milliliters of growth medium in the six milliliter polystyrene tube for the ten to the sixth dilution. Vortex briefly for a few seconds.Repeat the procedure for ten to the seventh, ten to the eighth, ten to the ninth, and ten to the tenth dilutions. Next remove the original culture medium from the DF1 cells on the 12 well plates. And add one milliliter of diluted virus into each well in duplicate.Allow the cells to grow at 37 degrees celsius and 5 CO2 for at least seven days. Begin the infection procedure by first anesthetizing a seven week old RIP-Tag RIP-tva mouse. Apply eye lubricant to both eyes to prevent corneal drying.Shave the hair from the chest cavity of the RIP-Tag RIP-tva mouse, position the mouse on its back with the chest facing up on an absorbent lab bench paper on top of a snuggle safe warmer. Perform a toe pinch to check the animal for nonresponsiveness and to confirm full anesthesia effect. Extend the front limbs and secure them with tape.Mark the chest of the mouse for injection. Mark the location midway between the sternal notch and the top of the xiphoid process, and slightly left anatomically of the sternum. Then scrub the anterior chest wall with either a povidone iodine scrub or a chlorhexidine scrub, followed by a 70%isopropyl alcohol or a 70%ethanol soaked gauze sponge.Draw 50 microliters of air into a sterile 28.5 gauge insulin syringe to create space between the plunger and the meniscus of a 500 microliter syringe. Draw up 100 microliters of virus. The airspace without any liquid on the wall is crucial for seeing the cardiac pulse.Keep the needle upright, hold the skin of mouse taut with one hand and insert the needle into the marked location. When a bright red pulse of blood appears in the syringe, stop advancing the needle and fix the depth of the needle in the mouse with one hand. Use the other hand to carefully and slowly push the plunger to deliver the viral suspension over about a 60 second period.Deliver 10-20 microliters whenever a bright red pulse of blood appears in the syringe. The continuous entrance of red oxygenated blood into the transparent needle hub indicates the proper positioning of the needle into the left ventricle. After the last push of the plunder to deliver viral suspension and before seeing the next red pulse of blood, quickly retract the needle out of the chest cavity.Apply gentle pressure over the injection site for at least one minute to reduce the bleeding. Then carefully move the mouse onto a heating pad or under a heat lamp until it is fully conscious. RIP-Tag RIP-tva mice were infected with the indicated RCASBP-Bcl-xL retro virus at seven weeks of age and euthanized at 16 weeks of age.This photograph shows representative synaptophysin staining of metastatic pancreatic neuroendocrine tumors in pancreatic lymph nodes. Here the RIP-Tag RIP-tva mice were infected with the indicated RCASBP-RHAM B.This photograph shows the representative synaptophysin staining of metastatic pancreatic neuroendocrine tumors in pancreatic lymph nodes. Here the synaptophysin staining is seen in the liver after injection of the RCASBP-RHAMM B virus.It is important to remember the title of greater than ten to the eight infectious units per milliliter is required for in vivo infection of proliferating TVA cells in RIP-Tag RIP-tva mouse and RCASBP retro viral rector can deliver CDNA up to 2.5 kilobases. After the development of this mouse model, it paved the way to a paradigm shifting finding that BCL-xL actually promotes cancer metastasis independent of it's antiapoptotic function.

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Cancer Research

8.7K Views.  Weill Cornell Medicine. The overall goal of this procedure is to identify and characterize metastatic factors by gene transfer into the Novel RIP-Tag;RIP-tva mouse model. This method can help answer key questions in the cancer metastasis field such as identifying the drivers and the Novel therapeutic targets. The main advantage of this mouse model of cancer is to identify metastatic factors by somatic gene transfer into pancreatic beta cell precursor legions.Begin by harvesting one 15 centimeter dish of virus...

Video: Identification and Characterization of Metastatic Factors by Gene Transfer into the Novel RIP-Tag; RIP-tva Murine Model

We present a protocol to demonstrate a novel somatic gene transfer system utilizing RIP-Tag; RIP-tva mouse model to study the function of genes in metastasis. The avian retroviruses are delivered intracardiacally to ensure gene transfer into pre-malignant, noninvasive lesions of pancreatic &#946; cells in adult...

intracardiac delivery of viral vectors: a technique to inject viral vectors intracardially to study pancreatic metastasis in murine model

This video describes the protocol for intracardiac injection of retroviruses into the transgenic mouse to ensure gene transfer into proliferating pancreatic &#946; premalignant lesions. This method can also help in assessing the functions of candidate genes in tumor...

Intracardiac Delivery of Viral Vectors: A Technique to Inject Viral Vectors Intracardially to Study Pancreatic Metastasis in Murine Model

method for the isolation and identification of mrnas, micrornas and protein components of ribonucleoprotein complexes from cell extracts using rip-chip

Method for the Isolation and Identification of mRNAs, microRNAs and Protein Components of Ribonucleoprotein Complexes from Cell Extracts using RIP-Chip

A step by step protocol to isolating and identifying RNA associated complexes through...

gene transfer into the chicken auditory organ by in ovo micro-electroporation

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

The auditory organ mediates hearing. Here we present a modified in ovo micro-electroporation method optimized for studying auditory progenitor cell proliferation and differentiation in the developing chicken auditory organ.

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

gene transfer into older chicken embryos by ex ovo electroporation

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

A method of gene transfer into chicken embryos at later incubation stages (older than Hamburger and Hamilton stage (HH) 22) is described. This method overcomes disadvantages of in ovo electroporation applied to older chicken embryos and is a useful technique to study gene function and regulation at older developmental...

Gene Transfer into Older Chicken Embryos by ex ovo Electroporation

developing a virtual reality video game to simulate rip currents

Developing a Virtual Reality Video Game to Simulate Rip Currents

Rip currents are among the deadliest meteorological hazards in the United States. In order to demonstrate the proper actions to take when caught in a rip current in a memorable and engaging way, a virtual reality video game is...

initiation of metastatic breast carcinoma by targeting of the ductal epithelium with adenovirus-cre: a novel transgenic mouse model of breast cancer

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

generating a murine orthotopic metastatic breast cancer model and performing murine radical mastectomy

Generating a Murine Orthotopic Metastatic Breast Cancer Model and Performing Murine Radical Mastectomy

We introduce a murine orthotopic breast cancer model and radical mastectomy model with bioluminescence technology to quantify the tumor burden to mimic human breast cancer...

culture of embryonic mouse cochlear explants and gene transfer by electroporation

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear.  We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

murine model of metastatic liver tumors in the setting of ischemia reperfusion injury

Murine Model of Metastatic Liver Tumors in the Setting of Ischemia Reperfusion Injury

We describe in detail a clinically relevant colorectal cancer liver metastases (CRLM) tumor model and the influence of liver ischemia reperfusion (I/R) in tumor growth and metastasis. This model can help to better understand the mechanisms underlying surgery-induced promotion of liver metastatic...

induction of murine intestinal inflammation by adoptive transfer of effector cd4+cd45rbhigh t cells into immunodeficient mice

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

Here, we present a protocol to induce colonic inflammation in mice by adoptive transfer of syngeneic CD4+CD45RBhigh T cells into T and B cell deficient recipients. Clinical and histopathological features mimic human inflammatory bowel diseases. This method allows the study of the initiation of colonic inflammation and progression of...

Induction of Murine Intestinal Inflammation by Adoptive Transfer of Effector CD4+CD45RBhigh T Cells into Immunodeficient Mice

a robust discovery platform for the identification of novel mediators of melanoma metastasis

A Robust Discovery Platform for the Identification of Novel Mediators of Melanoma Metastasis

This article describes a workflow of techniques employed for testing novel candidate mediators of melanoma metastasis and their mechanism(s) of action.

identification of rare bacterial pathogens by 16s rrna gene sequencing and maldi-tof ms

Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and molecular techniques (16S rRNA gene sequencing) permit the identification of rare bacterial pathogens in routine diagnostics. The goal of this protocol lies in the combination of both techniques which leads to more accurate and reliable...

efficient production and identification of crispr/cas9-generated gene knockouts in the model system danio rerio

Efficient Production and Identification of CRISPR/Cas9-generated Gene Knockouts in the Model System Danio rerio

Targeted genome editing in the model system Danio rerio (zebrafish) has been greatly facilitated by the emergence of CRISPR-based approaches. Herein, we describe a streamlined, robust protocol for generation and identification of CRISPR-derived nonsense alleles that incorporates the heteroduplex mobility assay and identification of mutations using next-generation...

Efficient Production and Identification of CRISPR/Cas9-generated Gene Knockouts in the Model System Danio rerio

injection of syngeneic murine melanoma cells to determine their metastatic potential in the lungs

Injection of Syngeneic Murine Melanoma Cells to Determine Their Metastatic Potential in the Lungs

Metastasis plays a profound role in the virulence of cancer, accounting for an estimated 90% of deaths.  We report a protocol for a metastatic melanoma model in mice that is useful for determining the efficacy of therapeutic agents against this clinical...

gene transfer to the developing mouse inner ear by in vivo electroporation

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

The mouse inner ear is a placode-derived sensory organ whose developmental program is elaborated during gestation. We define an in utero gene transfer technique consisting of three steps: mouse ventral laparotomy, transuterine microinjection, and in vivo electroporation. We use digital video microscopy to demonstrate the critical experimental embryological...

Gene Transfer to the Developing Mouse Inner Ear by In Vivo Electroporation

in vivo gene transfer to schwann cells in the rodent sciatic nerve by electroporation

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

Here, we present an in vivo technique for gene transfer to Schwann cells (SCs) in the rodent sciatic nerve. This simple technique is useful for investigating signaling mechanisms involved in the development and maintenance of myelinating...

In Vivo Gene Transfer to Schwann Cells in the Rodent Sciatic Nerve by Electroporation

experimental metastatic melanoma mouse model: a platform to study the metastatic potential of melanoma cells in the lungs

In this video, melanoma cells are intravenously injected through the tail vein in the mouse model. The melanoma cells further travel through the circulatory system, adapting to the distant microenvironment and causing metastasis in organs like...

Experimental Metastatic Melanoma Mouse Model: A Platform to Study the Metastatic Potential of Melanoma Cells in the Lungs

investigating interactions between histone modifying enzymes and transcription factors in vivo by fluorescence resonance energy transfer

Investigating Interactions Between Histone Modifying Enzymes and Transcription Factors in vivo by Fluorescence Resonance Energy Transfer

Fluorescence resonance energy transfer (FRET) is an imaging technique for detecting protein interactions in living cells. Here, a FRET protocol is presented to study the association of histone-modifying enzymes with transcription factors that recruit them to the target promoters for epigenetic regulation of gene expression in plant...

Investigating Interactions Between Histone Modifying Enzymes and Transcription Factors in vivo by Fluorescence Resonance Energy Transfer

a novel in vivo gene transfer technique and in vitro cell based assays for the study of bone loss in musculoskeletal disorders

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation of precursor cells into osteoclasts is regulated by cytokines and growth factors. Here, a novel gene transfer technique for differentiation of osteoclasts in vivo and cell culture protocols for differentiating precursor cells into osteoclasts in vitro as a method to study the effects of cytokines on osteoclastogenesis are described.

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Advanced Animal Model of Colorectal Metastasis in Liver: Imaging Techniques and Properties of Metastatic Clones

Patients with a limited number of hepatic metastases and slow rates of progression can be successfully treated with local treatment approaches1,2. However, little is known about the heterogeneity of liver metastases, and animal models capable of evaluating the development of individual metastatic colonies are needed. Here, we present an advanced model of hepatic metastases that provides the ability to quantitatively visualize the development of individual tumor clones in the liver and estimate their growth kinetics and colonization efficiency. We generated a panel of monoclonal derivatives of HCT116 human colorectal cancer cells stably labeled with luciferase and tdTomato and possessing different growth properties. With a splenic injection followed by a splenectomy, the majority of these clones are able to generate hepatic metastases, but with different frequencies of colonization and varying growth rates. Using the In Vivo&#160;Imaging System (IVIS), it is possible to visualize and quantify metastasis development with in vivo luminescent and ex vivo fluorescent imaging. In addition, Diffuse Luminescent Imaging Tomography (DLIT) provides a 3D distribution of liver metastases in vivo. Ex vivo fluorescent imaging of harvested livers provides quantitative measurements of individual hepatic metastatic colonies, allowing for the evaluation of the frequency of liver colonization and the growth kinetics of metastases. Since the model is similar to clinically observed liver metastases, it can serve as a modality for detecting genes associated with liver metastasis and for testing potential ablative or adjuvant treatments for liver metastatic disease.

The ability of metastatic clones to colonize distant sites depends on their proliferation capacity and/or their ability to survive in the host microenvironment without significant proliferation. Here, we present an animal model that allows quantitative visualization of both types of liver colonization by metastatic clones.

Patients with a limited number of hepatic metastases and slow rates of progression can be successfully treated with local treatment approaches1,2. ...

A Syngeneic Mouse Model of Metastatic Renal Cell Carcinoma for Quantitative and Longitudinal Assessment of Preclinical Therapies

Renal cell carcinoma (RCC) affects &#62; 60,000 people in the United States annually, and ~ 30% of RCC patients have multiple metastases at the time of diagnosis. Metastatic RCC (mRCC) is incurable, with a median survival time of only 18 months. Immune-based interventions (e.g., interferon (IFN) and interleukin (IL)-2) induce durable responses in a fraction of mRCC patients, and multikinase inhibitors (e.g., sunitinib or sorafenib) or anti-VEGF receptor monoclonal antibodies (mAb) are largely palliative, as complete remissions are rare. Such shortcomings in current therapies for mRCC patients provide the rationale for the development of novel treatment protocols. A key component in the preclinical testing of new therapies for mRCC is a suitable animal model. Beneficial features that recapitulate the human condition include a primary renal tumor, renal tumor metastases, and an intact immune system to investigate any therapy-driven immune effector responses and the formation of tumor-induced immunosuppressive factors. This report describes an orthotopic mRCC mouse model that has all of these features. We describe an intrarenal implantation technique using the mouse renal adenocarcinoma cell line Renca, followed by the assessment of tumor growth in the kidney (primary site) and lungs (metastatic site).

Implementation of an orthotopic model of renal cell carcinoma in immunocompetent mice affords the investigator a clinically-relevant system defined by the presence of a primary renal tumor and lung metastases in the same animal. This system can be used to preclinically test a variety of treatments in vivo.

Renal cell carcinoma (RCC) affects &#62; 60,000 people in the United States annually, and ~ 30% of RCC patients have multiple metastases at the time of ...

A Mouse Model of Fatigue Induced by Peripheral Irradiation

Cancer-related fatigue (CRF) is a distressing and costly condition that often affects patients receiving cancer treatments, including radiation therapy. Here we describe a method using targeted peripheral irradiation to induce fatigue-like behavior in mice. With appropriate shielding, the irradiation targets the lower abdominal/pelvic region of the mouse, sparing the brain, in an effort to model radiation treatment received by individuals with pelvic cancers. We deliver an irradiation dose that is sufficient to induce fatigue-like behavior in mice, measured by voluntary wheel-running activity (VWRA), without causing obvious morbidity. Since wheel running is a normal, voluntary behavior in mice, its use should have little confounding effect on other behavioral tests or biological measures. Hence, wheel running can be used as a feasible outcome measure in understanding the behavioral and biological correlates of fatigue. CRF is a complex condition with frequent comorbidities, and likely has causes related both to cancer and its various treatments. The methods described in this paper are useful for investigating radiation-induced changes that contribute to the development of CRF and, more generally, to explore the biological networks that can explain the development and persistence of a peripherally-triggered but centrally-driven behavior like fatigue.

We describe a method using targeted peripheral irradiation to induce fatigue-like behavior in mice. The selected non-lethal irradiation dose leads to a week-long reduction in voluntary wheel-running activity.

Cancer-related fatigue (CRF) is a distressing and costly condition that often affects patients receiving cancer treatments, including radiation therapy. ...

Virus Delivery of CRISPR Guides to the Murine Prostate for Gene Alteration

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) for prostate cancer are hampered by tumor heterogeneity and its complex microevolution dynamics. Traditional prostate cancer mouse models include, amongst others, germline and conditional knockouts, transgenic expression of oncogenes, and xenograft models. Generation of de novo mutations in these models is complex, time-consuming, and costly. In addition, most of traditional models target the majority of the prostate epithelium, whereas human prostate cancer is well known to evolve as an isolated event in only a small subset of cells. Valuable models need to simulate not only prostate cancer initiation, but also progression to advanced disease.
Here we describe a method to target a few cells in the prostate epithelium by transducing cells by viral particles. The delivery of an engineered virus to the murine prostate allows alteration of gene expression in the prostate epithelia. Virus type and quantity will hereby define the number of targeted cells for gene alteration by transducing a few cells for cancer initiation and many cells for gene therapy. Through surgery-based injection in the anterior lobe, distal from the urinary track, the tumor in this model can expand without impairing the urinary function of the animal. Furthermore, by targeting only a subset of prostate epithelial cells the technique enables clonal expansion of the tumor, and therefore mimics human tumor initiation, progression, as well as invasion through the basal membrane.
This novel technique provides a powerful prostate cancer model with improved physiological relevance. Animal suffering is limited, and since no additional breeding is required, overall animal count is reduced. At the same time, analysis of new candidate genes and pathways is accelerated, which in turn is more cost efficient.

This protocol describes a newly established method for virus delivery to the murine prostate. Using either CRISPR/Cas9 technology, gene overexpression, or Cre recombinase delivery, the technique allows orthotopic alteration of gene expression and implements a novel mouse model for prostate cancer.

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) ...

Enrichment and Characterization of the Tumor Immune and Non-immune Microenvironments in Established Subcutaneous Murine Tumors

The tumor immune microenvironment (TIME) has recently been recognized as a critical mediator of treatment response in solid tumors, especially for immunotherapies. Recent clinical advances in immunotherapy highlight the need for reproducible methods to accurately and thoroughly characterize the tumor and its associated immune infiltrate. Tumor enzymatic digestion and flow cytometric analysis allow broad characterization of numerous immune cell subsets and phenotypes; however, depth of analysis is often limited by fluorophore restrictions on panel design and the need to acquire large tumor samples to observe rare immune populations of interest. Thus, we have developed an effective and high throughput method for separating and enriching the tumor immune infiltrate from the non-immune tumor components. The described tumor digestion and centrifugal density-based separation technique allows separate characterization of tumor and tumor immune infiltrate fractions and preserves cellular viability, and thus, provides a broad characterization of the tumor immunologic state. This method was used to characterize the extensive spatial immune heterogeneity in solid tumors, which further demonstrates the need for consistent whole tumor immunologic profiling techniques. Overall, this method provides an effective and adaptable technique for the immunologic characterization of subcutaneous solid murine tumors; as such, this tool can be used to better characterize the tumoral immunologic features and in the preclinical evaluation of novel immunotherapeutic strategies.

Here we describe a method to separate and enrich components of the tumor immune and non-immune microenvironment in established subcutaneous tumors. This technique allows for the separate analysis of tumor immune infiltrate and non-immune tumor fractions which can permit comprehensive characterization of the tumor immune microenvironment.

The tumor immune microenvironment (TIME) has recently been recognized as a critical mediator of treatment response in solid tumors, especially for ...

Three-Dimensional Bone Extracellular Matrix Model for Osteosarcoma

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with diagnostic or prognostic difficulties. OS comprises genotypically and phenotypically heterogeneous cancer cells. Bone microenvironment elements are proved to account for tumor heterogeneity and disease progression. Bone extracellular matrix (BEM) retains the microstructural matrices and biochemical components of native extracellular matrix. This tissue-specific niche provides a favorable and long-term scaffold for OS cell seeding and proliferation. This article provides a protocol for the preparation of BEM model and its further experimental application. OS cells can grow and differentiate into multiple phenotypes consistent with the histopathological complexity of OS clinical specimens. The model also allows visualization of diverse morphologies and their association with genetic alterations and underlying regulatory mechanisms. As homologous to human OS, this BEM-OS model can be developed and applied to the pathology and clinical research of OS.

The bone extracellular matrix (BEM) model for osteosarcoma (OS) is well established and shown here. It can be used as a suitable scaffold for mimicking primary tumor growth in vitro and providing an ideal model for studying the histologic and cytogenic heterogeneity of OS.

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with ...

Liver ischemia and reperfusion (I/R) injury, a common clinical challenge, remains an inevitable pathophysiological process that has been shown to induce multiple tissue and organ damage. Despite recent advances and therapeutic approaches, the overall morbidity has remained unsatisfactory especially in patients with underlying parenchymal abnormalities. In the context of aggressive cancer growth and metastasis, surgical I/R is suspected to be the promoter regulating tumor recurrence. This article aims to describe a clinically relevant murine model of liver I/R and colorectal liver metastasis. In doing so, we aim to assist other investigators in establishing and perfecting this model for their routine research practice to better understand the effects of liver I/R on promoting liver metastases.

We describe in detail a clinically relevant colorectal cancer liver metastases (CRLM) tumor model and the influence of liver ischemia reperfusion (I/R) in tumor growth and metastasis. This model can help to better understand the mechanisms underlying surgery-induced promotion of liver metastatic growth.

Liver ischemia and reperfusion (I/R) injury, a common clinical challenge, remains an inevitable pathophysiological process that has been shown to induce ...

Analyzing Tumor Gene Expression Factors with the CorExplorer Web Portal

Differential gene expression analysis is an important technique for understanding disease states. The machine learning algorithm CorEx has shown utility in analyzing differential expression of groups of genes in tumor RNA-seq in a way that may be helpful for advancing precision oncology. However, CorEx produces many factors that can be challenging to analyze and connect to existing understanding. To facilitate such connections, we have built a website, CorExplorer, that allows users to interactively explore the data and answer common questions related to its analysis. We trained CorEx on RNA-seq gene expression data for four tumor types: ovarian, lung, melanoma, and colorectal. We then incorporated corresponding survival, protein-protein interactions, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments, and heatmaps into the website for association with the factor graph visualization. Here we employ example protocols to illustrate use of the database for comprehending the significance of the learned tumor factors in the context of this external data.

We introduce the CorExplorer web portal, an resource for exploration of tumor RNA sequencing factors found by the machine learning algorithm CorEx (Correlation Explanation), and show how factors can be analyzed relative to survival, database annotations, protein-protein interactions, and one another to gain insight into tumor biology and therapeutic interventions.

Differential gene expression analysis is an important technique for understanding disease states. The machine learning algorithm CorEx has shown utility ...

Monitoring Breast Cancer Growth and Metastatic Colony Formation in Mice using Bioluminescence

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several animal models have been generated, including the widely used orthotopic mouse models, where cancer cells are injected into the mammary fat pad. However, these models cannot help monitor tumor growth kinetics and metastatic colonization. Cutting-edge tools to monitor cancer cells in real time in mice will significantly advance the understanding of tumor biology. 
Here, breast cancer cell lines stably expressing luciferase and green fluorescent protein (GFP) were established. Specifically, this technique contains two sequential steps initiated by measuring the luciferase activity in vitro and followed by the implantation of the cancer cells into mammary fat pads of nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. After the injection, both the tumor growth and metastatic colonization are monitored in real time by the noninvasive bioluminescence imaging system. Then, the quantification of GFP-expressing metastases in the lungs will be examined by fluorescence microscopy to validate the observed bioluminescence results. This sophisticated system combining luciferase and fluorescence-based detection tools evaluates cancer metastasis in vivo, which has great potential for use in breast cancer therapeutics and disease management.

Here, we describe a noninvasive monitoring method involving luciferase and green fluorescent protein expression in various breast cancer cell lines. This protocol provides a technique to monitor tumor formation and metastatic colonization in real time in mice.

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several ...

Metastasis is a complex process, requiring cells to overcome barriers that are only incompletely modeled by in vitro assays. A systematic workflow was established using robust, reproducible in vivo models and standardized methods to identify novel players in melanoma metastasis. This approach allows for data inference at specific experimental stages to precisely characterize a gene's role in metastasis. Models are established by introducing genetically modified melanoma cells via intracardiac, intradermal, or subcutaneous injections into mice, followed by monitoring with serial in vivo imaging. Once preestablished endpoints are reached, primary tumors and/or metastases-bearing organs are harvested and processed for various analyses. Tumor cells can be sorted and subjected to any of several 'omics' platforms, including single-cell RNA sequencing. Organs undergo imaging and immunohistopathological analyses to quantify the overall burden of metastases and map their specific anatomic location. This optimized pipeline, including standardized protocols for engraftment, monitoring, tissue harvesting, processing, and analysis, can be adopted for patient-derived, short-term cultures and established human and murine cell lines of various solid cancer types.

This article describes a workflow of techniques employed for testing novel candidate mediators of melanoma metastasis and their mechanism(s) of action.

Metastasis is a complex process, requiring cells to overcome barriers that are only incompletely modeled by in vitro assays. A systematic workflow was ...