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Posts Tagged ‘animal models of disease’


Gene-editing startup raising $10M to expand staff
Nov 25, 2015

Reporter: Stephen J. Williams,Ph.D.

From the Mineapolis/St. Paul Journal

source from: http://www.bizjournals.com/twincities/news/2015/11/25/gene-editing-startup-raising-10m-to-expand-staff.html 

Katharine Grayson
Staff reporter
Minneapolis / St. Paul Business Journal

Recombinetics Inc. is seeking $10 million in funding as it ramps up sales of its genetically tweaked animals.
The St. Paul-based biotech company’s recent round has already brought in about about $2.8 million from friends and family, said Chief Operating Officer Kyle Dawley. Company officials hope to close out the round within the next two months and add about 10 employees to its staff of 25.

 

 

Recombinetics edits pigs' genes for biomedical research purposes

Recombinetics edits pigs’ genes for biomedical research purposes. Photo source: Simone Van Den Berg

Recombinetics uses gene-editing technology to tweak animals for the agribusiness and biomedical markets. It’s biomedical business centers around pigs, which the company modifies for research purposes. That side of the company’s business already generates revenue, Dawley said, though he declined to reveal sales figures.

The company focuses on pigs, touting them as better research subjects than mice when it comes to testing medical devices and drugs for use in humans.

“Pigs are — size-wise and genetically — a lot more like humans than rats and mice,” Dawley said.

One of Recombinetics’ long-term goals is grow human organs inside pigs.

The company aims to modify livestock for food consumption as well. One of its projects calls for creating hornless cattle by taking a gene from one breed and putting into another.

Recombinetics expects food ventures may get a boost from the Food and Drug Administration’s recent approval of a genetically engineered salmon called “AquAdvantage.” The fish grows faster than traditional salmon thanks to the introduction of trout genes.

Recombinetics has raised $15 million since its founding.

Katharine Grayson covers med tech, clean tech, technology, health care and venture capital.

 

See also Surrogen, Inc., which produces transgenic pigs for purpose of large animal models of disease.

Other posts on this Open Access Journal where I have discussed the utility of the minipig as a large animal model of disease include:

The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research

The SCID Pig II: Researchers Develop Another SCID Pig, And Another Great Model For Cancer Research

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Humanized Mice May Revolutionize Cancer Drug Discovery

 

Curator: Stephen J. Williams, Ph.D.

Decades ago cancer research and the process of oncology drug discovery was revolutionized by the development of mice deficient in their immune system, allowing for the successful implantation of human-derived tumors. The ability to implant human tumors without rejection allowed researchers to study how the kinetics of human tumor growth in its three-dimensional environment, evaluate potential human oncogenes and drivers of oncogenesis, and evaluate potential chemotherapeutic therapies. Indeed, the standard preclinical test for antitumor activity has involved the subcutaneous xenograft model in immunocompromised (SCID or nude athymic) mice. More detail is given in the follow posts in which I describe some early pioneers in this work as well as the development of large animal SCID models:

Heroes in Medical Research: Developing Models for Cancer Research

The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research

The SCID Pig II: Researchers Develop Another SCID Pig, And Another Great Model For Cancer Research

This strategy (putting human tumor cells into immunocompromised mice and testing therapeutic genes and /or compounds) has worked extremely well for most cytotoxic chemotherapeutics (those chemotherapeutic drugs with mechanisms of action related to cell kill, vital cell functions, and cell cycle). For example the NCI 60 panel of human tumor cell lines has proved predictive for the chemosensitivity of a wide range of compounds.

Even though the immunocompromised model has contributed greatly to the chemotherapeutic drug discovery process. using these models to develop the new line of immuno-oncology products has been met with challenges three which I highlight below with curated database of references and examples.

From a practical standpoint development of a mouse which can act as a recipient for human tumors yet have a humanized immune system allows for the preclinical evaluation of antitumoral effect of therapeutic antibodies without the need to use neutralizing antibodies to the comparable mouse epitope,   thereby reducing the complexity of the study and preventing complications related to pharmacokinetics.

Champions Oncology Files Patents for Use of PDX Platform in Immune-Oncology

Hackensack, NJ – August 17, 2015 – Champions Oncology, Inc. (OTC: CSBR), engaged in the development of advanced technology solutions and services to personalize the development and use of oncology drugs, today announced that it has filed two patent applications with the United States Patent and Trademark Office (USPTO) relating to the development and use of mice with humanized immune systems to test immune-oncology drugs and therapeutic cancer vaccines.

Dr. David Sidransky, the founder and Chairman of Champions Oncology commented, “Drug development ‎in the immune-oncology space is fundamentally changing our approach to cancer treatment. These patents represent potentially invaluable tools for developing and personalizing immune therapy based on cutting edge sequence analysis, bioinformatics and our unique in vivo models.”

Joel Ackerman, Chief Executive Officer of Champions Oncology stated, “Developing intellectual property related to our Champions TumorGraft® platform has been an important component of strategy. The filing of these patents is an important milestone in leveraging our research and development investment to expand our platform and create proprietary tools for use by our pharmaceutical partners. We continue to look for additional revenue streams to supplement our fee-for-service business and we believe these patents will help us capture more of the value we create for our customers in the future.”

The first patent filing covers the methodology used by the Company to create a mouse model, containing a humanized immune system and a human tumor xenograft, which is capable of testing the efficacy of immune-oncology agents, both as single agents and in combination with anti-neoplastic drugs. The second patent filing relates to the detection of neoantigens and their role in the development of anti-cancer vaccines.

Keren Pez, Chief Scientific Officer, explained, “In the last few years, there has been a significant increase in cancer research that focuses on exploring the power of the human immune system to attack tumors. However, it’s challenging to test immune-oncology agents in traditional animal models due to the major differences between human and murine immune systems. The Champions ImmunoGraft™ platform has the unique ability of mimicking a human adaptive immune response in the mice, which allows us to specifically evaluate a variety of cancer therapeutics that modulate human immunity.

“Therapeutic vaccines that trigger the immune system to mount a response against a growing tumor are another area of intense interest. The development of an effective vaccine remains challenging but has an outstanding curative potential. Tumors harbor mutations in DNA that result in the translation of aberrant proteins. While these proteins have the potential to provoke an immune response that destructs early-stage cancer development, often the immune response becomes insufficient. Vaccines can trigger it by proactively challenging the system with these specific mutated peptides. Nevertheless, developing anti-cancer vaccines that effectively inhibit tumor growth has been complicated, partially due to challenges in finding the critical mutations, among others difficulties. With the more recent advances in genome sequencing, it’s now possible to identify tumor-specific antigens, or neoantigens, that naturally develop as an individual’s tumor grows and mutates,” she continued.

Traumatic spinal cord injury in mice with human immune systems.

Carpenter RS, Kigerl KA, Marbourg JM, Gaudet AD, Huey D, Niewiesk S, Popovich PG.

Exp Neurol. 2015 Jul 17;271:432-444. doi: 10.1016/j.expneurol.2015.07.011. [Epub ahead of print]

Inflamm Bowel Dis. 2015 Jul;21(7):1652-73. doi: 10.1097/MIB.0000000000000446.

Use of Humanized Mice to Study the Pathogenesis of Autoimmune and Inflammatory Diseases.

Koboziev I1, Jones-Hall Y, Valentine JF, Webb CR, Furr KL, Grisham MB.

Author information

Abstract

Animal models of disease have been used extensively by the research community for the past several decades to better understand the pathogenesis of different diseases and assess the efficacy and toxicity of different therapeutic agents. Retrospective analyses of numerous preclinical intervention studies using mouse models of acute and chronic inflammatory diseases reveal a generalized failure to translate promising interventions or therapeutics into clinically effective treatments in patients. Although several possible reasons have been suggested to account for this generalized failure to translate therapeutic efficacy from the laboratory bench to the patient’s bedside, it is becoming increasingly apparent that the mouse immune system is substantially different from the human. Indeed, it is well known that >80 major differences exist between mouse and human immunology; all of which contribute to significant differences in immune system development, activation, and responses to challenges in innate and adaptive immunity. This inconvenient reality has prompted investigators to attempt to humanize the mouse immune system to address important human-specific questions that are impossible to study in patients. The successful long-term engraftment of human hematolymphoid cells in mice would provide investigators with a relatively inexpensive small animal model to study clinically relevant mechanisms and facilitate the evaluation of human-specific therapies in vivo. The discovery that targeted mutation of the IL-2 receptor common gamma chain in lymphopenic mice allows for the long-term engraftment of functional human immune cells has advanced greatly our ability to humanize the mouse immune system. The objective of this review is to present a brief overview of the recent advances that have been made in the development and use of humanized mice with special emphasis on autoimmune and chronic inflammatory diseases. In addition, we discuss the use of these unique mouse models to define the human-specific immunopathological mechanisms responsible for the induction and perpetuation of chronic gut inflammation.

J Immunother Cancer. 2015 Apr 21;3:12. doi: 10.1186/s40425-015-0056-2. eCollection 2015.

Human tumor infiltrating lymphocytes cooperatively regulate prostate tumor growth in a humanized mouse model.

Roth MD1, Harui A1.

Author information

Abstract

BACKGROUND:

The complex interactions that occur between human tumors, tumor infiltrating lymphocytes (TIL) and the systemic immune system are likely to define critical factors in the host response to cancer. While conventional animal models have identified an array of potential anti-tumor therapies, mouse models often fail to translate into effective human treatments. Our goal is to establish a humanized tumor model as a more effective pre-clinical platform for understanding and manipulating TIL.

METHODS:

The immune system in NOD/SCID/IL-2Rγnull (NSG) mice was reconstituted by the co-administration of human peripheral blood lymphocytes (PBL) or subsets (CD4+ or CD8+) and autologous human dendritic cells (DC), and animals simultaneously challenged by implanting human prostate cancer cells (PC3 line). Tumor growth was evaluated over time and the phenotype of recovered splenocytes and TIL characterized by flow cytometry and immunohistochemistry (IHC). Serum levels of circulating cytokines and chemokines were also assessed.

RESULTS:

A tumor-bearing huPBL-NSG model was established in which human leukocytes reconstituted secondary lymphoid organs and promoted the accumulation of TIL. These TIL exhibited a unique phenotype when compared to splenocytes with a predominance of CD8+ T cells that exhibited increased expression of CD69, CD56, and an effector memory phenotype. TIL from huPBL-NSG animals closely matched the features of TIL recovered from primary human prostate cancers. Human cytokines were readily detectible in the serum and exhibited a different profile in animals implanted with PBL alone, tumor alone, and those reconstituted with both. Immune reconstitution slowed but could not eliminate tumor growth and this effect required the presence of CD4+ T cell help.

CONCLUSIONS:

Simultaneous implantation of human PBL, DC and tumor results in a huPBL-NSG model that recapitulates the development of human TIL and allows an assessment of tumor and immune system interaction that cannot be carried out in humans. Furthermore, the capacity to manipulate individual features and cell populations provides an opportunity for hypothesis testing and outcome monitoring in a humanized system that may be more relevant than conventional mouse models.

Methods Mol Biol. 2014;1213:379-88. doi: 10.1007/978-1-4939-1453-1_31.

A chimeric mouse model to study immunopathogenesis of HCV infection.

Bility MT1, Curtis A, Su L.

Author information

Abstract

Several human hepatotropic pathogens including chronic hepatitis C virus (HCV) have narrow species restriction, thus hindering research and therapeutics development against these pathogens. Developing a rodent model that accurately recapitulates hepatotropic pathogens infection, human immune response, chronic hepatitis, and associated immunopathogenesis is essential for research and therapeutics development. Here, we describe the recently developed AFC8 humanized liver- and immune system-mouse model for studying chronic hepatitis C virus and associated human immune response, chronic hepatitis, and liver fibrosis.

PMID:

25173399

[PubMed – indexed for MEDLINE]

PMCID:

PMC4329723

Free PMC Article

Immune humanization of immunodeficient mice using diagnostic bone marrow aspirates from carcinoma patients.

Werner-Klein M, Proske J, Werno C, Schneider K, Hofmann HS, Rack B, Buchholz S, Ganzer R, Blana A, Seelbach-Göbel B, Nitsche U, Männel DN, Klein CA.

PLoS One. 2014 May 15;9(5):e97860. doi: 10.1371/journal.pone.0097860. eCollection 2014.

From 2015 AACR National Meeting in Philadelphia

LB-050: Patient-derived tumor xenografts in humanized NSG mice: a model to study immune responses in cancer therapy
Sunday, Apr 19, 2015, 3:20 PM – 3:35 PM
Minan Wang1, James G. Keck1, Mingshan Cheng1, Danying Cai1, Leonard Shultz2, Karolina Palucka2, Jacques Banchereau2, Carol Bult2, Rick Huntress2. 1The Jackson Laboratory, Sacramento, CA; 2The Jackson Laboratory, Bar Harbor, ME

 

References

  1. Paull KD, Shoemaker RH, Hodes L, Monks A, Scudiero DA, Rubinstein L, Plowman J, Boyd MR. J Natl Cancer Inst. 1989;81:1088–1092. [PubMed]
  2. Shi LM, Fan Y, Lee JK, Waltham M, Andrews DT, Scherf U, Paull KD, Weinstein JN. J Chem Inf Comput Sci. 2000;40:367–379. [PubMed]
  3. Monks A, Scudiero D, Skehan P, Shoemaker R, Paull K, Vistica D, Hose C, Langley J, Cronise P, Vaigro-Wolff A, et al. J Natl Cancer Inst. 1991;83:757–766. [PubMed]
  4. Potti A, Dressman HK, Bild A, et al. Genomic signatures to guide the use of chemotherapeutics. Nat Med. 2006;12:1294–1300. [PubMed]
  5. Baggerly KA, Coombes KR. Deriving chemosensitivity from cell lines: forensic bioinformatics and reproducible research in high-throughput biology. Ann Appl Stat. 2009;3:1309–1334.
  6. Carlson, B. Putting Oncology Patients at Risk Biotechnol Healthc. 2012 Fall; 9(3): 17–21.
  7. Salter KH, Acharya CR, Walters KS, et al. An Integrated Approach to the Prediction of Chemotherapeutic Response in Patients with Breast Cancer. Ouchi T, ed. PLoS ONE. 2008;3(4):e1908. NOTE RETRACTED PAPER

 

Other posts on this site on Animal Models, Disease and Cancer Include:

 

Heroes in Medical Research: Developing Models for Cancer Research

Guidelines for the welfare and use of animals in cancer research

Model mimicking clinical profile of patients with ovarian cancer @ Yale School of Medicine

Vaccines, Small Peptides, aptamers and Immunotherapy [9]

Immunotherapy in Cancer: A Series of Twelve Articles in the Frontier of Oncology by Larry H Bernstein, MD, FCAP

Mouse With ‘Humanized Version’ Of Human Language Gene Provides Clues To Language Development

The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research

The SCID Pig II: Researchers Develop Another SCID Pig, And Another Great Model For Cancer Research

 

 

 

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The SCID Pig II: Researchers Develop Another SCID Pig, And Another Great Model For Cancer Research

 

Updated 6/25/2019

Writer. Reporter: Stephen J. Williams, Ph.D.

gottingen minipig2

 

 

The choice of suitable animal model of disease may define future success or failure for drug development, basic and translational research, or biomarker discovery projects.   Indeed, as highlighted in one of my earlier posts “Heroes in Medical Research: Developing Models for Cancer Research”, the choice of animal to model a human disease can have drastic implications in the basic researchers ability to understand metabolic and genetic factors causally associated with disease development. As described in that post the King rat model led to our understanding of the genetics of early development and sex determination while early mouse models helped us to understand the impact of microenvironment on cell fate and the discovery of stem cells. In addition, transgenic and immunodeficient mice resulted in transformational studies on our understanding of cancer. Small rodent models are ideal for following reasons:

  • Ease of genetic manipulation
  • Availability of well-defined models
  • Ease of low cost of use

Regardless of these benefits many investigators in industry and academia are looking to models of human disease in animals more closely resembling human anatomy, physiology, and genetics.

 

There is a growing need for alternative animal models in cancer research.

 

As I had discussed in another of my earlier posts “The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research”, the pig is gaining notoriety and acceptance as a very suitable animal to model human disease as minipigs and humans have:

  • Similar physiology
  • Similar genetics: >90% homology
  • Similar anatomic dimensions: i.e. Adult Gottingen minipigs are 70kg (adult human male weight)
  • Similar organ size and structure to humans organ size and structure
  • Pig genome sequencing project nearly complete
  • Ability to manipulate pig genetics

The post had discussed the development of a severe combined immunodeficient (SCID) pig by investigators at Iowa State and Kansas State University. This line of pigs, selected on a specific diet, could act as recipients for human cancer cell lines, a proof of their SCID phenotype.

A report featured on Fierce Biotech Research “MU Scientists Successfully Transplant, Grow Stem Cells in Pigs” discussed the development of a new genetically-modified immunodeficient porcine model by researchers at the University of Missouri, recently published in Proceedings of the National Academy of Sciences[1].

These pigs are available from the National Swine Resource and Research Center (http://nsrrc.missouri.edu).

For the report on Fierce Biotech Research please follow the link below:

http://www.fiercebiotechresearch.com/press-releases/mu-scientists-successfully-transplant-grow-stem-cells-pigs

 

The report in FierceBiotech highlights the type of studies an immunocompromised pig model would be useful for including:

  • Regenerative medicine
  • Xenotransplantation
  • Tumor growth and efficacy studies

 

Comments in the post from the investigators explained the benefits of developing such a porcine model system including:

“The rejection of transplants and grafts by host bodies is a huge hurdle for medical researchers,” said R. Michael Roberts, Curators Professor of Animal Science and Biochemistry and a researcher in the Bond Life Sciences Center. “By establishing that these pigs will support transplants without the fear of rejection, we can move stem cell therapy research forward at a quicker pace.”

The studies main investigators, Drs. Randall Prather and R. Michael Roberts, both of University of Missouri, along with first authors Kiho Lee, Deug-Nam Kwon and Toshihiko Ezashi, used biallellic mutation of the RAG2 gene in Gottingen minipig fibroblasts and then subsequent somatic cell nuclear transfer (SCNT) to produce the RAG2-/- animals. (Rag2 is a protein involved in V(D)J recombination of antibodies during early B and T cell development. See GeneCard link above)

As proof of their SCID phenotype the authors showed that

  1. these RAG2-/- animals could act as host for human induced pluripotent stem cells
  2. act as recipient for allogeneic porcine stem cells
  3. reduced levels of (CD21+) B cells and (CD3+) T cells
  4. growth retardation if housed under standard, non-sterile conditions

Details of the study are given below:

Methodology Used

For Production of Gottingen minipigs carrying the RAG2 mutation

To produce targeted mutations in RAG2:

  • TALENS () were constructed to produced mutation in exon 2 of RAG2
  • Constructed TALENS and reporter electroporated in fetal-derived pig fibroblasts
  • SCNT used to transfer RAG2 mutant nuclei to donor oocytes
  • 9 embryo transfers resulted in 22 live piglets
  • Piglets genotyped as either monoallelic or biallelic RAG2 mutant
  • RAG2wild-type and mutants housed in either pathogen-free or normal housing conditions

To verify SCID phenotype of litter by either

  1. Graft acceptance of human iPSCs and teratoma formation

–          Fibroblasts from human umbilical cord reprogrammed to pluripotency; verified by pluripotent markers POUSF1, NANOG, SSEA-3)

–          Two human and porcine iPSC lines with trophoblastic properties[2] were injected subcutaneously in ear or flank

–          Tumor formation analyzed by immunohistochemistry using markers:

CTNNBI (B-catenin)

VWF (von Willebrand

DES and ACTG2

GFAP and ENO2

Human specific MFN1 (both antibody and gene primers)

  1. Flow Cytometry

–          Analysis of piglet spleen cells for B cell population (CD21)

–          Analysis of piglet spleen cell for T cell population (CD3)

C.    Histology

– histo evaluation of thymus, spleen

– marker evaluation of spleen using anti-CD79A (B cells), CD3 (T cells),

CD335 (NK cells)

Results

TALEN produced a variety of indels (insertion/deletions) and three RAG2 mutatnt colonies (containing monoallelic, mix of mono and biallelic) used for SCNT.

Three litters produced 16 piglets (eight survived [four mono and four biallelic]

Biallelic RAG2 mutants showed slower weight gain than wild type or monoallelic mutants with signs of inflammation and apoptosis in spleen and designated “failure to thrive” in standard housing…needed a clean environment to thrive.

Biallelic mutant pigs lacked mature CD21 B cells and CD3 T cells but contained macrophages and NK cells.

Implantation of human and allogenic porcine pluripotent stem cells (trophoblastic) showed rapid development of teratomas.
References

  1. Lee K, Kwon DN, Ezashi T, Choi YJ, Park C, Ericsson AC, Brown AN, Samuel MS, Park KW, Walters EM et al: Engraftment of human iPS cells and allogeneic porcine cells into pigs with inactivated RAG2 and accompanying severe combined immunodeficiency. Proceedings of the National Academy of Sciences of the United States of America 2014, 111(20):7260-7265.
  2. Ezashi T, Matsuyama H, Telugu BP, Roberts RM: Generation of colonies of induced trophoblast cells during standard reprogramming of porcine fibroblasts to induced pluripotent stem cells. Biology of reproduction 2011, 85(4):779-787.

Updated 6/25/2019

The following articles represent an update on the ability to create genetically predisposed porcine models of cancer.  The ability to utilize transposable elements to introduce genetic changes in porcine cells in combination with Somatic Cell Nuclear Transfer technology with the ultimate goal to create a transgenic minipig is discussed.  The next two articles describe the ability of the scid pig to act as a recipient for human ovarian cancer cells and description of a transgenic inducible porcine intestinal tumor model.

Transgenic Res. 2011 Jun;20(3):533-45. doi: 10.1007/s11248-010-9438-x. Epub 2010 Aug 29.

Pig transgenesis by Sleeping Beauty DNA transposition.

Jakobsen JE1Li JKragh PMMoldt BLin LLiu YSchmidt MWinther KDSchyth BDHolm IEVajta GBolund LCallesen HJørgensen ALNielsen ALMikkelsen JG.

Author information

Abstract

Modelling of human disease in genetically engineered pigs provides unique possibilities in biomedical research and in studies of disease intervention. Establishment of methodologies that allow efficient gene insertion by non-viral gene carriers is an important step towards development of new disease models. In this report, we present transgenic pigs created by Sleeping Beauty DNA transposition in primary porcine fibroblasts in combination with somatic cell nuclear transfer by handmade cloning. Göttingen minipigs expressing green fluorescent protein are produced by transgenesis with DNA transposon vectors carrying the transgene driven by the human ubiquitin C promoter. These animals carry multiple copies (from 8 to 13) of the transgene and show systemic transgene expression. Transgene-expressing pigs carry both transposase-catalyzed insertions and at least one copy of randomly inserted plasmid DNA. Our findings illustrate critical issues related to DNA transposon-directed transgenesis, including coincidental plasmid insertion and relatively low Sleeping Beauty transposition activity in porcine fibroblasts, but also provide a platform for future development of porcine disease models using the Sleeping Beauty gene insertion technology.

This paper makes use of two technologies: transposon mediated gene transfer to introduce foreign DNA, for example a disease predisposition gene, into oocytes or early embryos, without the use of viral vectors; and use of SCNT to clone a minipig from viable embryos.

 

The transposon mediated system is based on the Sleeping Beauty (SB) vector system, which is a cut and paste DNA transposon belonging to the Tc1/mariner superfamily of transposable elements(1).  Transposable DNA elements are mobile genetic elements which integrate into genomic DNA, in the case of the SB system into discrete sequence elements of actively transcribed genes.  The system consists of two entities: 1) a transposase responsible for cutting and pasting the mobile element and 2) the transposon; the vectorial DNA sequence which is inserted into genomic DNA.  SB transposition has been used to integrate exogenous genetic elements into the genome of various mammalian species(2) and to make tumor models in mice (3-7) and to transform, ex-vivo, porcine ovarian epithelial cells (8) and to stably integrate GFP containing vectors into porcine fibroblast genome(9).  Because of the efficiency and nonviral integration of exogenous vectors into mammalian systems, Sleeping Beauty system has been considered as a potential therapeutic gene transfer modality (10-12).

 

  1. Li, Z.H., Liu, D.P., Wang, J., Guo, Z.C., Yin, W.X., and Liang, C.C. Inversion and transposition of Tc1 transposon of C. elegans in mammalian cells. Somat Cell Mol Genet. 1998; 24:363-369.
  2. Balciuniene, J., Nagelberg, D., Walsh, K.T., Camerota, D., Georlette, D., Biemar, F., et al. Efficient disruption of Zebrafish genes using a Gal4-containing gene trap. BMC Genomics. 2013; 14:619.
  3. Romano, G., Marino, I.R., Pentimalli, F., Adamo, V., and Giordano, A. Insertional mutagenesis and development of malignancies induced by integrating gene delivery systems: implications for the design of safer gene-based interventions in patients. Drug News Perspect. 2009; 22:185-196.
  4. Dupuy, A.J. Transposon-based screens for cancer gene discovery in mouse models. Semin Cancer Biol. 2010; 20:261-268.
  5. Dupuy, A.J., Akagi, K., Largaespada, D.A., Copeland, N.G., and Jenkins, N.A. Mammalian mutagenesis using a highly mobile somatic Sleeping Beauty transposon system. Nature. 2005; 436:221-226.
  6. Dupuy, A.J., Clark, K., Carlson, C.M., Fritz, S., Davidson, A.E., Markley, K.M., et al. Mammalian germ-line transgenesis by transposition. Proc Natl Acad Sci U S A. 2002; 99:4495-4499.
  7. Dupuy, A.J., Fritz, S., and Largaespada, D.A. Transposition and gene disruption in the male germline of the mouse. Genesis. 2001; 30:82-88.
  8. Hamilton, T.C., Williams, S.J., and Cvetkovic, D. 2010. Cancer Compositions, Animal Models, and Methods of Use Thereof. U.S.P. Office, editor. USA: Fox Chase Cancer Center.
  9. Clark, K.J., Carlson, D.F., Foster, L.K., Kong, B.W., Foster, D.N., and Fahrenkrug, S.C. Enzymatic engineering of the porcine genome with transposons and recombinases. BMC Biotechnol. 2007; 7:42.
  10. Ivics, Z., and Izsvak, Z. Transposable elements for transgenesis and insertional mutagenesis in vertebrates: a contemporary review of experimental strategies. Methods Mol Biol. 2004; 260:255-276.
  11. Liu, H., Liu, L., Fletcher, B.S., and Visner, G.A. Sleeping Beauty-based gene therapy with indoleamine 2,3-dioxygenase inhibits lung allograft fibrosis. FASEB J. 2006; 20:2384-2386.
  12. Ohlfest, J.R., Lobitz, P.D., Perkinson, S.G., and Largaespada, D.A. Integration and long-term expression in xenografted human glioblastoma cells using a plasmid-based transposon system. Mol Ther. 2004; 10:260-268.

 

A second paper, by Larry Shook and Geoffrey Clark’s groups describe the production of ex vivo transformed porcine breast cancer line, driven by inactivation of BRCA1.  In this paper normal porcine breast epithelial cells were immortalized by transfection with SV large T antigen (SV-LT) and upon inactivation of porcine BRCA1 in these immortalized cell lines, developed phenotype characteristic of transformed cells and exhibited cancer stem cell characteristics.  The end point assay for transformation was growth in soft agar however the authors did not confirm malignancy in either SCID mice or SCID pigs.

Front Genet. 2015 Aug 25;6:269. doi: 10.3389/fgene.2015.00269. eCollection 2015.

A porcine model system of BRCA1 driven breast cancer.

Donninger H1Hobbing K2Schmidt ML3Walters E4Rund L5Schook L5Clark GJ2.

Author information

Abstract

BRCA1 is a breast and ovarian tumor suppressor. Hereditary mutations in BRCA1 result in a predisposition to breast cancer, and BRCA1expression is down-regulated in ~30% of sporadic cases. The function of BRCA1 remains poorly understood, but it appears to play an important role in DNA repair and the maintenance of genetic stability. Mouse models of BRCA1 deficiency have been developed in an attempt to understand the role of the gene in vivo. However, the subtle nature of BRCA1 function and the well-known discrepancies between human and murine breast cancer biology and genetics may limit the utility of mouse systems in defining the function of BRCA1 in cancer and validating the development of novel therapeutics for breast cancer. In contrast to mice, pig biological systems, and cancer genetics appear to more closely resemble their human counterparts. To determine if BRCA1 inactivation in pig cells promotes their transformation and may serve as a model for the human disease, we developed an immortalized porcine breast cell line and stably inactivated BRCA1 using miRNA. The cell line developed characteristics of breast cancer stem cells and exhibited a transformed phenotype. These results validate the concept of using pigs as a model to study BRCA1 defects in breast cancer and establish the first porcine breast tumor cell line.

 

 

Figure 1. Immortalization of pig mammary epithelial cells. Primary pig breast epithelial cells were stably transfected with an SV40 LT expression construct and selected in puromycin. Surviving cells were serially passaged to confirm immortalization.

 

fgene-06-00269-g001 immortalized breast porcine epithelial cells

 

 

Figure 3. Loss of BRCA1 enhances pig mammary epithelial cell growth. (A) Serially passaging the pig mammary epithelial cells stably knocked down for BRCA1 resulted in an altered morphology compared to those cells stably expressing the LacZ miRNA. (B) 2 × 104 cells/well were plated in 6-well plates and cell growth was determined by counting the number of cells at the indicated times. Error bars show standard error, p < 0.05.

fgene-06-00269-g003growthofbrcaminusporbrepith

 

 

Figure 5. Loss of BRCA1 enhances the transformed phenotype of pig mammary epithelial cells. (A) The pig breast epithelial cells stably expressing BRCA1 miRNA were plated in soft agar and scored for growth 14 days later. Representative photomicrographs are shown in the top panel and data from three independent experiments quantitated in the bar graph in the lower panel. (B) 1 × 106 cells/well were plated in polyHEMA-coated 12-well plates and cell viability assessed 48 h later by trypan blue staining. Error bars show standard error, p < 0.05.

fgene-06-00269-g005brca1minuporbrepithcolonies

 

A third paper describes the development, in Gottingen minipigs, of a transgenic inducible model of intestinal cancer.

Mol Oncol. 2017 Nov;11(11):1616-1629. doi: 10.1002/1878-0261.12136. Epub 2017 Oct 10.

A genetically inducible porcine model of intestinal cancer.

Callesen MM1Árnadóttir SS1Lyskjaer I1Ørntoft MW1Høyer S2Dagnaes-Hansen F3Liu Y4Li R4Callesen H4Rasmussen MH1Berthelsen MF3Thomsen MK3Schweiger PJ5Jensen KB5Laurberg S6Ørntoft TF1Elverløv-Jakobsen JE3Andersen CL1.

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Abstract

Transgenic porcine cancer models bring novel possibilities for research. Their physical similarities with humans enable the use of surgical procedures and treatment approaches used for patients, which facilitates clinical translation. Here, we aimed to develop an inducible oncopig model of intestinal cancer. Transgenic (TG) minipigs were generated using somatic cell nuclear transfer by handmade cloning. The pigs encode two TG cassettes: (a) an Flp recombinase-inducible oncogene cassette containing KRAS-G12D, cMYC, SV40LT – which inhibits p53 – and pRB and (b) a 4-hydroxytamoxifen (4-OHT)-inducible Flp recombinase activator cassette controlled by the intestinal epithelium-specific villin promoter. Thirteen viable transgenic minipigs were born. The ability of 4-OHT to activate the oncogene cassette was confirmed in vitro in TG colonic organoids and ex vivo in tissue biopsies obtained by colonoscopy. In order to provide proof of principle that the oncogene cassette could also successfully be activated in vivo, three pigs were perorally treated with 400 mg tamoxifen for 2 × 5 days. After two months, one pig developed a duodenal neuroendocrine carcinoma with a lymph node metastasis. Molecular analysis of the carcinoma and metastasis confirmed activation of the oncogene cassette. No tumor formation was observed in untreated TG pigs or in the remaining two treated pigs. The latter indicates that tamoxifen delivery can probably be improved. In summary, we have generated a novel inducible oncopig model of intestinal cancer, which has the ability to form metastatic disease already two months after induction. The model may be helpful in bridging the gap between basic research and clinical usage. It opens new venues for longitudinal studies of tumor development and evolution, for preclinical assessment of new anticancer regimens, for pharmacology and toxicology assessments, as well as for studies into biological mechanisms of tumor formation and metastasis.

 

Other posts on this site related to Cancer Research Tools include

The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research

Heroes in Medical Research: Developing Models for Cancer Research

Reprogramming Induced Pleuripotent Stem Cells

The Cancer Research Concentration @ Leaders in Pharmaceutical Business Intelligence

A Synthesis of the Beauty and Complexity of How We View Cancer

Guidelines for the welfare and use of animals in cancer research

Gene Therapy and the Genetic Study of Disease: @Berkeley and @UCSF – New DNA-editing technology spawns bold UC initiative as Crispr Goes Global

 

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Heroes in Medical Research: Developing Models for Cancer Research

Author, Curator: Stephen J. Williams, Ph.D.

 

The current rapid progress in cancer research would have never come about if not for the dedication of past researchers who had developed many of the scientific tools we use today. In this issue of Heroes in Medical Research I would like to give tribute to the researchers who had developed the some of the in-vivo and in-vitro models which are critical for cancer research.

 

The Animal Modelers in Cancer Research

Helen Dean King, Ph.D. (1869-1955)

Helen Dean King

Helen Dean King, Ph.D. from www.ExplorePAhistory.com; photo Courtesy of the Wistar Institute Archive Collection, Philadelphia, PA

 

 

The work of Dr. Helen Dean King on rat inbreeding led to development of strains of laboratory animals. Dr. King taught at Bryn Mawr College, then worked at University of Pennsylvania and the Wistar Institute under famed geneticist Thomas Hunt Morgan, researching if inbreeding would produce harmful genetic traits.   At University of Pennsylvania she examined environmental and genetic factors on gender determination.

 

 

 

 

Important papers include [1-6]as well as the following contributions:

“Studies in Inbreeding”, “Life Processes in Gray Norway Rats During Fourteen Years in Captivity”, doctoral thesis on embryologic development in toads (1899)

 

Milestones include:

 

1909    started albino rat breeding and bred 20 female and male from same litter (King colony) to 25

successive generations (inbreeding did not cause harmful traits)

 

1919     started to domesticate the wild Norwegian rats that ran thru Philadelphia (six pairs Norway rats

thru 28 generations)

A good reference for definitions of rat inbreeding versus line generation including a history of Dr. King’s work can be found at the site: Munificent Mischief Rattery and a brief history here.[7] In addition, Dr. King had investigated using rat strains as a possible recipient for tumor cells. The work was an important advent to the use of immunodeficient models for cancer research.

 

As shown below Philadelphia became a hotbed for research into embryology, development, genetics, and animal model development.

 

Beatrice Mintz, Ph.D.

(Beatrice Minz, Ph.D.; photo credit Fox Chase Cancer Center, www.pubweb.fccc.edu) Mintz

Dr. Mintz, an embryologist and cancer researcher from Fox Chase Cancer Center in Philadelphia, PA, contributed some of the most seminal discoveries leading to our current understanding of genetics, embryo development, cellular differentiation, and oncogenesis, especially melanoma, while pioneering techniques which allowed the development of genetically modified mice.

If you get the privilege of hearing her talk, take advantage of it. Dr. Mintz is one of those brilliant scientists who have the ability to look at a clinical problem from the viewpoint of a basic biological question and, at the same time, has the ability to approach the well-thought out questions with equally well thought out experimental design. For example, Dr. Mintz asked if a cell’s developmental fate was affected by location in the embryo. This led to her work by showing teratocarcinoma tumor cells in the developing embryo could revert to a more normal phenotype, essentially proving two important concepts in development and tumor biology:

  1. The existence of pluripotent stem cells
  2. That tumor cells are affected by their environment (which led to future concepts of the importance of tumor microenvironment on tumor growth

Other seminal discoveries included:

  • Development of the first mouse chimeras using novel cell fusion techniques
  • With Rudolf Jaenisch in 1974, showed integration of viral DNA from SV40, could be integrated into the DNA of developing mice and persist into adulthood somatic cells, the first transgenesis in mice which led ultimately to:
  • Development of the first genetically modified mouse model of human melanoma in 1993

Her current work, seen on the faculty webpage here, is developing mice with predisposition to melanoma to uncover risk factors associated with the early development of melanoma.

In keeping with the Philadelphia tradition another major mouse model which became seminal to cancer drug discovery was co-developed in the same city, same institute and described in the next section.

It is interesting to note that the first cloning of an animal, a frog, had taken place at the Institute for Cancer Research, later becoming Fox Chase Cancer Center, which was performed by Drs. Robert Briggs and Thomas J. King and reported in the 152 PNAS paper Transplantation of Living Nuclei From Blastula Cells into Enucleated Frogs’ Eggs.[8]

 

 The Immunodeficient Animal as a Model System for Cancer Research – Dr. Mel Bosma, Ph.D.

 

Bosma

Melvin J. Bosma, Ph.D.; photo credit Fox Chase Cancer Center

In the summer of 1980 at Fox Chase Cancer Center, Dr. Melvin J. Bosma and his co-researcher wife Gayle discovered mice with deficiencies in common circulating antibodies and since, these mice were littermates, realized they had found a genetic defect which rendered the mice immunodeficient (upon further investigation these mice were unable to produce mature B and T cells). These mice were the first scid (severe combined immunodeficiency) colony. The scid phenotype was later found to be a result of a spontaneous mutation in the enzyme Prkdc {protein kinase, DNA activated, catalytic polypeptide} involved in DNA repair, and ultimately led to a defect in V(D)J recombination of immunoglobulins.

The emergence of this scid mouse was not only crucial for AIDS research but was another turning point in cancer research , as researchers now had a robust in-vivo recipient for human tumor cells. The orthotopic xenograft of human tumor cells now allowed for studies on genetic and microenvironmental factors affecting tumorigenicity, as well as providing a model for chemotherapeutic drug development (see Suggitt for review and references)[9]. A discussion of the pros and cons of the xenograft system for cancer drug discovery would be too voluminous for this post and would warrant a full review by itself. But before the advent of such scid mouse systems researchers relied on spontaneous and syngeneic mouse tumor models such as the B16 mouse melanoma and Lewis lung tumor model.

Other scid systems have been developed such as in the dog, horse, and pig. Please see the following post on this site The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research. The athymic (nude) mouse (nu/nu) also is a popular immunodeficient mouse model used for cancer research

Two other in-vivo tumor models: Patient Derived Xenografts (PDX) and Genetically Engineered Mouse models (GEM) deserve their own separate discussion however the success of these new models can be attributed to the hard work of the aforementioned investigators. Therefore I will post separately and curate PDX and GEM models of cancer and highlight some new models which are having great impact on cancer drug development.

 

References

1.         Loeb L, King HD: Transplantation and Individuality Differential in Strains of Inbred Rats. The American journal of pathology 1927, 3(2):143-167.

2.         Lewis MR, Aptekman PM, King HD: Retarding action of adrenal gland on growth of sarcoma grafts in rats. J Immunol 1949, 61(4):315-319.

3.         Aptekman PM, Lewis MR, King HD: Tumor-immunity induced in rats by subcutaneous injection of tumor extract. J Immunol 1949, 63(4):435-440.

4.         Lewis MR, Aptekman PM, King HD: Inactivation of malignant tissue in tumor-immune rats. J Immunol 1949, 61(4):321-326.

5.         Lewis MR, King HD, et al.: Further studies on oncolysis and tumor immunity in rats. J Immunol 1948, 60(4):517-528.

6.         Aptekman PM, Lewis MR, King HD: A method of producing in inbred albino rats a high percentage of immunity from tumors native in their strain. J Immunol 1946, 52:77-86.

7.         Ogilvie MB: Inbreeding, eugenics, and Helen Dean King (1869-1955). Journal of the history of biology 2007, 40(3):467-507.

8.         Briggs R, King TJ: Transplantation of Living Nuclei From Blastula Cells into Enucleated Frogs’ Eggs. Proceedings of the National Academy of Sciences of the United States of America 1952, 38(5):455-463.

9.         Suggitt M, Bibby MC: 50 years of preclinical anticancer drug screening: empirical to target-driven approaches. Clinical cancer research : an official journal of the American Association for Cancer Research 2005, 11(3):971-981.

 

Other posts on this site about Cancer, Animal Models of Disease, and other articles in this series include:

The SCID Pig: How Pigs are becoming a Great Alternate Model for Cancer Research

A Synthesis of the Beauty and Complexity of How We View Cancer

Guidelines for the welfare and use of animals in cancer research

Importance of Funding Replication Studies: NIH on Credibility of Basic Biomedical Studies

FDA Guidelines For Developmental and Reproductive Toxicology (DART) Studies for Small Molecules

Report on the Fall Mid-Atlantic Society of Toxicology Meeting “Reproductive Toxicology of Biologics: Challenges and Considerations:

What`s new in pancreatic cancer research and treatment?

Heroes in Medical Research: Dr. Carmine Paul Bianchi Pharmacologist, Leader, and Mentor

Heroes in Medical Research: Dr. Robert Ting, Ph.D. and Retrovirus in AIDS and Cancer

Heroes in Medical Research: Barnett Rosenberg and the Discovery of Cisplatin

Richard Lifton, MD, PhD of Yale University and Howard Hughes Medical Institute: Recipient of 2014 Breakthrough Prizes Awarded in Life Sciences for the Discovery of Genes and Biochemical Mechanisms that cause Hypertension

Reuben Shaw, Ph.D., a geneticist and researcher at the Salk Institute: Metabolism Influences Cancer

 

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The SCID Pig:  How Pigs are becoming a Great Alternate Model for Cancer Research[1]

Author/Writer: Stephen J. Williams, Ph.D.©

The need for alternate models of human cancer

Many worldwide regulatory bodies are in agreement that proper choice of animal model is necessary for adequate extrapolation of toxicity and efficacy data from animal to human, considering the varied classes of therapeutics now being developed for oncology.  The inability of screens, reliant on human xenografts grown in immunocompromised mice to evaluate host-immune and species-dependent effects, has made development of alternative animal-models a priority.   This is evident in the fact that ninety percent of new anticancer drugs which showed anti-tumor efficacy in mouse preclinical models failed in human clinical studies. A recently developed “humanized” mouse model may assist in testing the metabolism of cancer drugs but still relies on older “immunosuppression” mouse models (http://stehlin.org/mouse-model-development/). This inadequacy of older, accepted models is clearly evident when evaluating safety and efficacy of adenoviral based gene therapies such as oncolytic conditionally-replicative adenovirus (CRAd).  Although new-generation CRAds present with a relative safe profile[2, 3], adenoviral particles, especially the Ad5 based virus used for most CRAds, have the tendency to replicate in non-tumor tissue, such as liver and lung, resulting in tissue-specific toxicities[4-7].  The manifestation of these toxicities is only evident in species permissive for viral replication, such as the pig. Indeed, one of the first clinical trials with older adenovirus gene therapy, resulting in severe hepatic toxicity and fatality, may have been prevented if more appropriate preclinical screens were conducted.  Thereafter, strict regulatory guidelines for adenoviral-based clinical trials have been issued, with particular emphasis on vector dosage, safety and toxicity[8]. Indeed, at Schering-Plough, a toxicology program was initiated to evaluate SCH 58500, and adenoviral gene therapy directed against p53, which involved use of non-immunogenic rats compared with testing in Yorkshire pigs made immunoreactive to the vector[9, 10].  In fact, data from the pig study revealed a faster clearance of virus as well as toxicities not seen in non-immunogenic, non-permissive hosts such as rat and mouse.

Therefore, development of a porcine model of cancer would permit both testing of both the efficacy and safety of these therapies in the same animal.

Development of large animal models of cancer

To date, large animal tumor models have been used for studying spontaneously formed tumors in dogs and cats [11](Vail, 2000, Cancer Invest), the most common being canine [12] and feline non-Hodgkin’s lymphoma [13]. The advantages of these companion models are the outbred nature of the animals, comparable size and kinetics to human tumors [14-18], and high incidence rates. Allografts of the outbred-canine transplanted venereal tumor have been used to test the ability to detect tumors using X-ray computed tomography and MRI with the ultimate goal of imaging-guided intervention. Researchers have recently utilized the spontaneously arising canine and feline soft tissue sarcomas to study effects of hyperthermia on chemotherapy pharmocokinetics, development of hypoxic cell markers, and cancer imaging techniques [15, 19-26]

Although it appears that, for a select number of tumor types, spontaneously arising tumors in large outbred animals can be useful to model the human disease, it is disappointing these spontaneous arising tumors are limited to discrete tumor types. However, due to recent advances in sequencing of several domestic animal genomes and the development of new cloning strategies, it is now very feasible to utilize other animal models more relevant to human disease, notably the miniature pig.

gottingen minipigThe Gottingen mini-pig

Large animals in medical research: Advantages of the minipig

Due to recent advances in sequencing of several domestic animal genomes [27, 28] and the development of new organism cloning technologies [29-31], it is now very feasible to utilize other species to model human disease, notably the pig. The development of porcine models of human disease has gained much interest lately. Advantages include the resemblance in anatomy, physiology, and genetic makeup with the human, as well as new methods to manipulate the pig genome [32, 33]. To date, porcine models of human metabolic syndrome [34] and diabetes [35], aortic aneurism [36], infectious disease resistance [32, 37], seizure [38], neurologic syndromes [33], and pancreatitis [39] have been developed. Recently, a genetically-engineered porcine model of cystic fibrosis was produced in collaboration with investigators at University of Iowa and Exemplar Genetics [40-42]. Additionally, Cho et al. successfully transplanted spontaneously transformed leukemic and lymphatic tumor cells in a major histocompatibility complex (MHC)-defined inbred miniature swine model [43], suggesting feasibility of an ex vivo strategy to develop a porcine tumor model. Porcine models have, also, been used to develop, test and refine surgical [44, 45] and laparoscopic techniques [46, 47], radio- and cryoablation protocols of tissues [48-52] and robotic surgery using the da Vinci Surgical SystemÒ [53, 54].  In addition, because of the size of porcine organs and their resemblance to the human (in genetics) the minipig is very useful and abundant of a source to isolate specific cell types for in vitro studies.  Below is a figure showing the comparable size of human and porcine ovaries to the mouse and  ability to purify  porcine ovarian epithelial cells and their similarity to human and mouse ovarian epithelial cells.

newslidemousehumanpigovarysizejpeg

Figure 1.  The human and pig ovary have similar size and can yield a greater number of isolated cells than one can get from a mouse ovary.

posehosemosepicforpostjpg

Figure 2.  Isolation and morphology of ovarian epithelial cells from three sources:

A) Devonshire/Yorkshire pig

B) normal human ovary

c) SV129/BL6  mouse

note cobblestone epithelial morphology from all three sources©

To date, there has been no allograft or xenograft model of cancer in pigs. The consensus amongst many surgeons suggests development of a minipig tumor model would be an invaluable tool for developing surgical skills. 

A recent advancement in porcine tumor modeling was made by collaboration between researchers from the laboratories of Dr. Stefan Bossmann and Deryl Troyer at Kansas State and Iowa State, respectively[1].  The joint collaboration resulted in the development of the first severe combined immunodeficient pig line (SCID pig) which was shown to be able to accept human tumor xenografts.  The line of immunodeficient pig was discovered when Yorkshire pigs were bred for increased feed efficiency and a line of pigs exhibited SCID-like symptoms including:

  • Decreased levels of circulating lymphocytes
  • Atrophied thymus and lymph nodes

The SCID phenotype in mice have been ascribed to defects in a DNA-dependent protein kinase gene which prevents variable-diversity-joining [V(D)J] gene region recombination[55].  There have been multiple genetic defects found in humans resulting in SCID, including defects in adenylate kinase2, Janus kinase 3, the IL2 receptor, and the IL-7 receptor[56]. The SCID phenotype in this pig line has a simple autosomal recessive inheritance pattern which, as described below in an interview with the authors, allows for the propagation of this porcine line.

An important feature of SCID models is the ability of these animals to act as a recipient of human tumorigenic cell lines.  In fact, growth of cell lines in SCID mice is a common test for tumorigenicity.  Therefore, to test if these pigs could act as recipients for human cancer cell lines, the authors inoculated the SCID Yorkshire pigs with 4 million A3755M human melanoma cells or PANC1 human pancreatic carcinoma cells subcutaneously in the left and right ears respectively of three pigs.  Some features of the results include:

  • All injection sites showed evidence (either histologic or palpable) of tumor growth
  • Tumors showed characteristic histologic features of malignant neoplasm including
  1. Bizarre and atypical mitotic figures
  2. Anisocytosis (different cell sizes and shapes; feature of malignancy)
  3. Anisokaryosis (different size and shape of nucleus)
  • tumors stained with anti-human mitochondrial antibody (a marker of epithelial cancer cells) showed strong cytoplasmic staining of neoplastic cells
  • interestingly no necrotic regions in the tumor

 

scidpigfig1Figure 3. Visual evidence of human tumor cells growing in SCID pig ear (day 20). B) Same picture as A) but circle outlines growth.  From reference 1. Basel et al., used with permission from Mary Liebert.

It is interesting to note that these tumors only grew roughly 10 x 5.5 mm, which is genrally large enough to do preclinical studies but may be too expensive to be of use for xenograft studies.  However it would be very feasible to conduct allograft studies in these SCID pigs.

Dr. Jack Dekkers, C.F. Curtiss Distinguished Professor and Section Leader of Animal Breeding and Genetics at Iowa State University, was kind to answer a few questions about the SCID pig model.

Question: You had mentioned this line was identified after breeding Yorkshire pigs for increased feed efficiency.  Have you identified or hypothesize which altered pathway or molecular defect which results in a SCID phenotype?  Is this SCID phenotype a result of a metabolic syndrome these pigs could have?

Dr. Dekkers: We indeed identified the SCID phenotype in a line of pigs that we had selected for increased feed efficiency. However, I don’t think this phenotype has anything to do with the selection we practiced; it was either already present in the founders of the line or it was a random mutation that occurred in the line, independent of the selection for feed efficiency. We have narrowed the mutation that causes the SCID in our pigs down to a chromosomal region and have a very strong candidate gene in that region that we are currently pursuing.

Question: In your opinion, is it possible to produce a highly inbred immunocompromised strain of pig such as a Gottingen minipig?

Dr. Dekkers: We are working on breeding the SCID mutation into mini pigs. But in the meantime, we have used bone marrow transfer to create a male that is homozygous SCID (it’s an autosomal recessive) and reproducing. This allows us to produce litters that are 50% SCID and 50% normal (carriers) by mating him to carrier females.

REFERENCES

1.         Basel MT, Balivada S, Beck AP, Kerrigan MA, Pyle MM, Dekkers JC, Wyatt CR, Rowland RR, Anderson DE, Bossmann SH et al: Human xenografts are not rejected in a naturally occurring immunodeficient porcine line: a human tumor model in pigs. BioResearch open access 2012, 1(2):63-68.

2.         Dobbelstein M: Replicating adenoviruses in cancer therapy. Curr Top Microbiol Immunol 2004, 273:291-334.

3.         Lichtenstein DL, Wold WS: Experimental infections of humans with wild-type adenoviruses and with replication-competent adenovirus vectors: replication, safety, and transmission. Cancer Gene Ther 2004, 11(12):819-829.

4.         Volpers C, Kochanek S: Adenoviral vectors for gene transfer and therapy. J Gene Med 2004, 6 Suppl 1:S164-171.

5.         Brand K, Arnold W, Bartels T, Lieber A, Kay MA, Strauss M, Dorken B: Liver-associated toxicity of the HSV-tk/GCV approach and adenoviral vectors. Cancer Gene Ther 1997, 4(1):9-16.

6.         Lieber A, He CY, Meuse L, Schowalter D, Kirillova I, Winther B, Kay MA: The role of Kupffer cell activation and viral gene expression in early liver toxicity after infusion of recombinant adenovirus vectors. J Virol 1997, 71(11):8798-8807.

7.         Keedy V, Wang W, Schiller J, Chada S, Slovis B, Coffee K, Worrell J, Thet LA, Johnson DH, Carbone DP: Phase I study of adenovirus p53 administered by bronchoalveolar lavage in patients with bronchioloalveolar cell lung carcinoma: ECOG 6597. J Clin Oncol 2008, 26(25):4166-4171.

8.         Assessment of adenoviral vector safety and toxicity: report of the National Institutes of Health Recombinant DNA Advisory Committee. Hum Gene Ther 2002, 13(1):3-13.

9.         Morrissey RE, Horvath C, Snyder EA, Patrick J, Collins N, Evans E, MacDonald JS: Porcine toxicology studies of SCH 58500, an adenoviral vector for the p53 gene. Toxicol Sci 2002, 65(2):256-265.

10.       Morrissey RE, Horvath C, Snyder EA, Patrick J, MacDonald JS: Rodent nonclinical safety evaluation studies of SCH 58500, an adenoviral vector for the p53 gene. Toxicol Sci 2002, 65(2):266-275.

11.       Vail DM, MacEwen EG: Spontaneously occurring tumors of companion animals as models for human cancer. Cancer Invest 2000, 18(8):781-792.

12.       Leifer CE, Matus RE: Canine lymphoma: clinical considerations. Semin Vet Med Surg (Small Anim) 1986, 1(1):43-50.

13.       MacEwen EG: Spontaneous tumors in dogs and cats: models for the study of cancer biology and treatment. Cancer Metastasis Rev 1990, 9(2):125-136.

14.       Schwyn U, Crompton NE, Blattmann H, Hauser B, Klink B, Parvis A, Ruslander D, Kaser-Hotz B: Potential tumour doubling time: determination of Tpot for various canine and feline tumours. Vet Res Commun 1998, 22(4):233-247.

15.       Zeman EM, Calkins DP, Cline JM, Thrall DE, Raleigh JA: The relationship between proliferative and oxygenation status in spontaneous canine tumors. Int J Radiat Oncol Biol Phys 1993, 27(4):891-898.

16.       LaRue SM, Fox MH, Withrow SJ, Powers BE, Straw RC, Cote IM, Gillette EL: Impact of heterogeneity in the predictive value of kinetic parameters in canine osteosarcoma. Cancer Res 1994, 54(14):3916-3921.

17.       Vail DM, Kisseberth WC, Obradovich JE, Moore FM, London CA, MacEwen EG, Ritter MA: Assessment of potential doubling time (Tpot), argyrophilic nucleolar organizer regions (AgNOR), and proliferating cell nuclear antigen (PCNA) as predictors of therapy response in canine non-Hodgkin’s lymphoma. Exp Hematol 1996, 24(7):807-815.

18.       Guglielmino R, Canese MG, Miniscalco B, Geuna M: Comparison of clinical, morphological, immunophenotypical and cytochemical characteristics of LGL leukemia/lymphoma in dog, cat and human. Eur J Histochem 1997, 41 Suppl 2:23-24.

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20.       Thrall DE, McEntee MC, Cline JM, Raleigh JA: ELISA quantification of CCI-103F binding in canine tumors prior to and during irradiation. Int J Radiat Oncol Biol Phys 1994, 28(3):649-659.

21.       Raleigh JA, La Dine JK, Cline JM, Thrall DE: An enzyme-linked immunosorbent assay for hypoxia marker binding in tumours. Br J Cancer 1994, 69(1):66-71.

22.       Thrall DE, Larue SM, Pruitt AF, Case B, Dewhirst MW: Changes in tumour oxygenation during fractionated hyperthermia and radiation therapy in spontaneous canine sarcomas. Int J Hyperthermia 2006, 22(5):365-373.

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34.       Spurlock ME, Gabler NK: The development of porcine models of obesity and the metabolic syndrome. J Nutr 2008, 138(2):397-402.

35.       Palin MF, Labrecque B, Beaudry D, Mayhue M, Bordignon V, Murphy BD: Visfatin expression is not associated with adipose tissue abundance in the porcine model. Domest Anim Endocrinol 2008, 35(1):58-73.

36.       Sadek M, Hynecek RL, Goldenberg S, Kent KC, Marin ML, Faries PL: Gene expression analysis of a porcine native abdominal aortic aneurysm model. Surgery 2008, 144(2):252-258.

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38.       Marchi N, Angelov L, Masaryk T, Fazio V, Granata T, Hernandez N, Hallene K, Diglaw T, Franic L, Najm I et al: Seizure-promoting effect of blood-brain barrier disruption. Epilepsia 2007, 48(4):732-742.

39.       Tao J, Gong D, Ji D, Xu B, Liu Z, Li L: Improvement of monocyte secretion function in a porcine pancreatitis model by continuous dose dependent veno-venous hemofiltration. Int J Artif Organs 2008, 31(8):716-721.

40.       Rogers CS, Abraham WM, Brogden KA, Engelhardt JF, Fisher JT, McCray PB, Jr., McLennan G, Meyerholz DK, Namati E, Ostedgaard LS et al: The porcine lung as a potential model for cystic fibrosis. Am J Physiol Lung Cell Mol Physiol 2008, 295(2):L240-263.

41.       Rogers CS, Stoltz DA, Meyerholz DK, Ostedgaard LS, Rokhlina T, Taft PJ, Rogan MP, Pezzulo AA, Karp PH, Itani OA et al: Disruption of the CFTR gene produces a model of cystic fibrosis in newborn pigs. Science 2008, 321(5897):1837-1841.

42.       Rogers CS, Hao Y, Rokhlina T, Samuel M, Stoltz DA, Li Y, Petroff E, Vermeer DW, Kabel AC, Yan Z et al: Production of CFTR-null and CFTR-DeltaF508 heterozygous pigs by adeno-associated virus-mediated gene targeting and somatic cell nuclear transfer. J Clin Invest 2008, 118(4):1571-1577.

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