scholarly journals Genetically Altered Mouse Models: the Good, the Bad, and the Ugly

2003 ◽  
Vol 14 (3) ◽  
pp. 154-174 ◽  
Author(s):  
Tamizchelvi Thyagarajan ◽  
Satish Totey ◽  
Mary Jo S. Danton ◽  
Ashok B. Kulkarni
Keyword(s):  
Gene Targeting ◽  
Mouse Models ◽  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Genetically Engineered ◽  
Murine Models ◽  
Functional Roles ◽  
Targeted Gene Disruption ◽  
Gene Knockout Mouse

Targeted gene disruption in mice is a powerful tool for generating murine models for human development and disease. While the human genome program has helped to generate numerous candidate genes, few genes have been characterized for their precise in vivo functions. Gene targeting has had an enormous impact on our ability to delineate the functional roles of these genes. Many gene knockout mouse models faithfully mimic the phenotypes of the human diseases. Because some models display an unexpected or no phenotype, controversy has arisen about the value of gene-targeting strategies. We argue in favor of gene-targeting strategies, provided they are used with caution, particularly in interpreting phenotypes in craniofacial and oral biology, where many genes have pleiotropic roles. The potential pitfalls are outweighed by the unique opportunities for developing and testing different therapeutic strategies before they are introduced into the clinic. In the future, we believe that genetically engineered animal models will be indispensable for gaining important insights into the molecular mechanisms underlying development, as well as disease pathogenesis, diagnosis, prevention, and treatment.

scholarly journals Physiological Functions of Mcl-1: Insights From Genetic Mouse Models

2021 ◽  
Vol 9 ◽  
Author(s):  
Hui San Chin ◽  
Nai Yang Fu
Keyword(s):  
Mouse Models ◽  
Developmental Stages ◽  
Cell Types ◽  
Genetically Engineered ◽  
Model Systems ◽  
Murine Models ◽  
Multiple Tumor ◽  
A Cell ◽  
Tumor Types

The ability to regulate the survival and death of a cell is paramount throughout the lifespan of a multicellular organism. Apoptosis, a main physiological form of programmed cell death, is regulated by the Bcl-2 family proteins that are either pro-apoptotic or pro-survival. The in vivo functions of distinct Bcl-2 family members are largely unmasked by genetically engineered murine models. Mcl-1 is one of the two Bcl-2 like pro-survival genes whose germline deletion causes embryonic lethality in mice. Its requisite for the survival of a broad range of cell types has been further unraveled by using conditional and inducible deletion murine model systems in different tissues or cell lineages and at distinct developmental stages. Moreover, genetic mouse cancer models have also demonstrated that Mcl-1 is essential for the survival of multiple tumor types. The MCL-1 locus is commonly amplified across various cancer types in humans. Small molecule inhibitors with high affinity and specificity to human MCL-1 have been developed and explored for the treatment of certain cancers. To facilitate the pre-clinical studies of MCL-1 in cancer and other diseases, transgenic mouse models over-expressing human MCL-1 as well as humanized MCL-1 mouse models have been recently engineered. This review discusses the current advances in understanding the physiological roles of Mcl-1 based on studies using genetic murine models and its critical implications in pathology and treatment of human diseases.

scholarly journals Mouse models for BRAF-induced cancers

2007 ◽  
Vol 35 (5) ◽  
pp. 1329-1333 ◽  
Author(s):  
C. Pritchard ◽  
L. Carragher ◽  
V. Aldridge ◽  
S. Giblett ◽  
H. Jin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mouse Models ◽  
Human Cancer ◽  
Cre Recombinase ◽  
Genetically Engineered ◽  
Mitogen Activated Protein Kinase ◽  
Braf Mutations ◽  
Single Nucleotide Change

Oncogenic mutations in the BRAF gene are detected in ∼7% of human cancer samples with a particularly high frequency of mutation in malignant melanomas. Over 40 different missense BRAF mutations have been found, but the vast majority (>90%) represent a single nucleotide change resulting in a valine→glutamate mutation at residue 600 (V600EBRAF). In cells cultured in vitro, V600EBRAF is able to stimulate endogenous MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] and ERK phosphorylation leading to an increase in cell proliferation, cell survival, transformation, tumorigenicity, invasion and vascular development. Many of these hallmarks of cancer can be reversed by treatment of cells with siRNA (small interfering RNA) to BRAF or by inhibiting MEK, indicating that BRAF and MEK are attractive therapeutic targets in cancer samples with BRAF mutations. In order to fully understand the role of oncogenic BRAF in cancer development in vivo as well as to test the in vivo efficacy of anti-BRAF or anti-MEK therapies, GEMMs (genetically engineered mouse models) have been generated in which expression of oncogenic BRaf is conditionally dependent on the Cre recombinase. The delivery/activation of the Cre recombinase can be regulated in both a temporal and spatial manner and therefore these mouse models can be used to recapitulate the somatic mutation of BRAF that occurs in different tissues in the development of human cancer. The data so far obtained following Cre-mediated activation in haemopoietic tissue and the lung indicate that V600EBRAF mutation can drive tumour initiation and that its primary effect is to induce high levels of cyclin D1-mediated cell proliferation. However, hallmarks of OIS (oncogene-induced senescence) are evident that restrain further development of the tumour.

scholarly journals DEPTOR Deficiency-Mediated mTORc1 Hyperactivation in Vascular Endothelial Cells Promotes Angiogenesis

2018 ◽  
Vol 46 (2) ◽  
pp. 520-531 ◽  
Author(s):  
Yan Ding ◽  
Lanlan Shan ◽  
Wenqing Nai ◽  
Xiaojun Lin ◽  
Ling Zhou ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Gene Knockout ◽  
Umbilical Vein ◽  
Vascular Endothelial Cell ◽  
Tube Formation ◽  
Vascular Endothelial

Background/Aims: The mechanistic target of rapamycin (mTOR) signaling pathway is essential for angiogenesis and embryonic development. DEP domain-containing mTOR-interacting protein (DEPTOR) is an mTOR binding protein that functions to inhibit the mTOR pathway In vitro experiments suggest that DEPTOR is crucial for vascular endothelial cell (EC) activation and angiogenic responses. However, knowledge of the effects of DEPTOR on angiogenesis in vivo is limited. This study aimed to determine the role of DEPTOR in tissue angiogenesis and to elucidate the molecular mechanisms. Methods: Cre/loxP conditional gene knockout strategy was used to delete the Deptor gene in mouse vascular ECs. The expression or distribution of cluster of differentiation 31 (CD31), vascular endothelial growth factor (VEGF) and hypoxia inducible factor-1 alpha (HIF-1α) were detected by immunohistochemical staining or western blot. Tube formation assay was used to measure angiogenesis in vitro. Results: Deptor knockdown led to increased expression of CD31, VEGF and HIF-1α in heart, liver, kidney and aorta. After treatment with rapamycin, their expression was significantly down regulated. In vitro, human umbilical vein endothelial cells (HUVECs) were transfected with DEPTOR-specific small interfering RNA (siRNA), which resulted in a significant increase in endothelial tube formation and migration rates. In contrast, DEPTOR overexpression markedly reduced the expression of CD31, VEGF and HIF-1α. Conclusions: Our findings demonstrated that deletion of the Deptor gene in vascular ECs resulted in upregulated expression of CD31 and HIF-1α, and further stimulated the expression of VEGF which promoted angiogenesis, indicating that disruption of normal angiogenic pathways may occur through hyperactivation of the mTORC1/HIF-1α/VEGF signaling pathway.

scholarly journals Genetic Mouse Models as In Vivo Tools for Cholangiocarcinoma Research

Cancers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1868 ◽  
Author(s):  
Oihane Erice ◽  
Adrian Vallejo ◽  
Mariano Ponz-Sarvise ◽  
Michael Saborowski ◽  
Arndt Vogel ◽  
...  
Keyword(s):  
Mouse Models ◽  
Molecular Mechanisms ◽  
Complex Disease ◽  
Current Knowledge ◽  
Genetic Alterations ◽  
In Vivo Model ◽  
In Vivo Models ◽  
Dismal Prognosis ◽  
Genetic Mouse Models

Cholangiocarcinoma (CCA) is a genetically and histologically complex disease with a highly dismal prognosis. A deeper understanding of the underlying cellular and molecular mechanisms of human CCA will increase our current knowledge of the disease and expedite the eventual development of novel therapeutic strategies for this fatal cancer. This endeavor is effectively supported by genetic mouse models, which serve as sophisticated tools to systematically investigate CCA pathobiology and treatment response. These in vivo models feature many of the genetic alterations found in humans, recapitulate multiple hallmarks of cholangiocarcinogenesis (encompassing cell transformation, preneoplastic lesions, established tumors and metastatic disease) and provide an ideal experimental setting to study the interplay between tumor cells and the surrounding stroma. This review is intended to serve as a compendium of CCA mouse models, including traditional transgenic models but also genetically flexible approaches based on either the direct introduction of DNA into liver cells or transplantation of pre-malignant cells, and is meant as a resource for CCA researchers to aid in the selection of the most appropriate in vivo model system.

Development of multi-drug loaded PEGylated nanodiamonds to inhibit tumor growth and metastasis in genetically engineered mouse models of pancreatic cancer

Nanoscale ◽  
2019 ◽  
Vol 11 (45) ◽  
pp. 22006-22018 ◽  
Author(s):  
Vijay Sagar Madamsetty ◽  
Krishnendu Pal ◽  
Sandeep Keshavan ◽  
Thomas R. Caulfield ◽  
Shamit Kumar Dutta ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Mouse Models ◽  
Genetically Engineered ◽  
Inhibit Tumor Growth ◽  
Schematic Representation ◽  
Genetically Engineered Mouse Models ◽  
Tumor Growth And Metastasis ◽  
Nano Formulation ◽  
Immune Competent Mouse

Schematic representation demonstrating the fabrication and in vivo evaluation of an immune-modulatory nano-formulation consisting of irinotecan and curcumin in immune-competent mouse models of pancreatic adenocarcinoma.

scholarly journals Preclinical Molecular Imaging for Precision Medicine in Breast Cancer Mouse Models

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
M. F. Fiordelisi ◽  
L. Auletta ◽  
L. Meomartino ◽  
L. Basso ◽  
G. Fatone ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Molecular Imaging ◽  
Animal Models ◽  
Early Detection ◽  
Mouse Models ◽  
Molecular Mechanisms ◽  
Clinical Medicine ◽  
High Sensitivity ◽  
Positron Emission

Precision and personalized medicine is gaining importance in modern clinical medicine, as it aims to improve diagnostic precision and to reduce consequent therapeutic failures. In this regard, prior to use in human trials, animal models can help evaluate novel imaging approaches and therapeutic strategies and can help discover new biomarkers. Breast cancer is the most common malignancy in women worldwide, accounting for 25% of cases of all cancers and is responsible for approximately 500,000 deaths per year. Thus, it is important to identify accurate biomarkers for precise stratification of affected patients and for early detection of responsiveness to the selected therapeutic protocol. This review aims to summarize the latest advancements in preclinical molecular imaging in breast cancer mouse models. Positron emission tomography (PET) imaging remains one of the most common preclinical techniques used to evaluate biomarker expression in vivo, whereas magnetic resonance imaging (MRI), particularly diffusion-weighted (DW) sequences, has been demonstrated as capable of distinguishing responders from nonresponders for both conventional and innovative chemo- and immune-therapies with high sensitivity and in a noninvasive manner. The ability to customize therapies is desirable, as this will enable early detection of diseases and tailoring of treatments to individual patient profiles. Animal models remain irreplaceable in the effort to understand the molecular mechanisms and patterns of oncologic diseases.

Of mice and models: improved animal models for biomedical research

2002 ◽  
Vol 11 (3) ◽  
pp. 115-132 ◽  
Author(s):  
Ernesto Bockamp ◽  
Marko Maringer ◽  
Christian Spangenberg ◽  
Stephan Fees ◽  
Stuart Fraser ◽  
...  
Keyword(s):  
Animal Models ◽  
Mouse Models ◽  
Biomedical Research ◽  
Applied Research ◽  
Mouse Genome ◽  
Gene Knockout ◽  
Genetic Disorders ◽  
Murine Models ◽  
Good State ◽  
Basic And Applied Research

The ability to engineer the mouse genome has profoundly transformed biomedical research. During the last decade, conventional transgenic and gene knockout technologies have become invaluable experimental tools for modeling genetic disorders, assigning functions to genes, evaluating drugs and toxins, and by and large helping to answer fundamental questions in basic and applied research. In addition, the growing demand for more sophisticated murine models has also become increasingly evident. Good state-of-principle knowledge about the enormous potential of second-generation conditional mouse technology will be beneficial for any researcher interested in using these experimental tools. In this review we will focus on practice, pivotal principles, and progress in the rapidly expanding area of conditional mouse technology. The review will also present an internet compilation of available tetracycline-inducible mouse models as tools for biomedical research ( http://www.zmg.uni-mainz.de/tetmouse/ ).

scholarly journals How Genetically Engineered Mouse Tumor Models Provide Insights Into Human Cancers

2011 ◽  
Vol 29 (16) ◽  
pp. 2273-2281 ◽  
Author(s):  
Katerina Politi ◽  
William Pao
Keyword(s):  
Mouse Models ◽  
Cancer Biology ◽  
Human Cancer ◽  
Genetically Engineered ◽  
Mouse Tumor ◽  
Tumor Models ◽  
Genetically Engineered Mouse Models ◽  
Human Cancers ◽  
Chemically Induced

Genetically engineered mouse models (GEMMs) of human cancer were first created nearly 30 years ago. These early transgenic models demonstrated that mouse cells could be transformed in vivo by expression of an oncogene. A new field emerged, dedicated to generating and using mouse models of human cancer to address a wide variety of questions in cancer biology. The aim of this review is to highlight the contributions of mouse models to the diagnosis and treatment of human cancers. Because of the breadth of the topic, we have selected representative examples of how GEMMs are clinically relevant rather than provided an exhaustive list of experiments. Today, as detailed here, sophisticated mouse models are being created to study many aspects of cancer biology, including but not limited to mechanisms of sensitivity and resistance to drug treatment, oncogene cooperation, early detection, and metastasis. Alternatives to GEMMs, such as chemically induced or spontaneous tumor models, are not discussed in this review.

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