1,721,170 research outputs found
MicroRNAs and Cancer: Short RNAs Go a Long Way
Full text linkMicroRNAs (miRNAs) may be important regulators of gene expression. By modulating oncogenic and tumor suppressor pathways they could, in principle, contribute to tumorigenesis. Consistent with this hypothesis, recurrent genetic and epigenetic alterations of individual miRNAs are found in some tumors. Functional studies are now elucidating the mechanism of action of putative oncogenic and tumor suppressor miRNAs
Producing and Concentrating Lenti-Cre for Mouse Infections
Full text linkLentiviral vectors offer versatility as vehicles for gene delivery. They can transduce a wide range of cell types and integrate into the host genome, which results in long-term expression of the transgene (Cre) both in vitro and in vivo. This protocol describes how lentiviral particles are produced, purified, and concentrated
NF-κB Fans the Flames of Lung Carcinogenesis
No full textThis perspective on Deng et al. (beginning on p. 424 in this issue of the journal) examines the link between NF-κB and lung tumorigenesis. Experiments in genetically engineered mouse models of lung cancers are elucidating protumorigenic roles of NF-κB activation in lung cancer pathogenesis. Our growing understanding of the tumor-promoting NF-κB downstream effector pathways could lead to the development of novel approaches for lung cancer therapy and chemoprevention
Whole-Mount X-Gal Staining of Mouse Tissues
Full text linkAlthough the development of improved mouse models, including conditional deletions, marks an exciting time in mouse genetics, it is important to characterize and validate these models. Cre reporter strains allow researchers to assess the recombinase expression profile and function in individual Cre mouse lines. These strains are engineered to express a reporter gene (usually LacZ) following the removal of a floxed STOP cassette, thus marking cell lineages that can be targeted with a given Cre line. This protocol provides a detailed method for the histochemical detection of β-galactosidase activity in Cre mouse strains
Genetically engineered mouse models of cancer reveal new insights about the antitumor immune response
No full textCancer is a complex disease that can originate in virtually all the tissues of the body, and tumors progress through many different stages during their development. While genetic mutations in the emerging cancer cells drive this disease, it has become increasingly clear that cancer development is strongly influenced by the surrounding microenvironment. Cells of the immune system are critical components of this extrinsic network of cancer regulators, contributing significantly to the microenvironment of most cancers and either promoting or inhibiting the initiation and progression of this disease. Genetically engineered mouse (GEM) mouse models of spontaneous cancer are starting to shape our understanding of how antitumor T cells may act to prevent or inhibit cancer progression in some settings and not others. Lessons learned from investigating spontaneous mouse cancer models have important implications for directing clinical efforts that attempt to direct a cancer patient's immune system to eradicate their disease.National Institutes of Health (U.S.) (Grant 1 U54 CA126515-01)National Cancer Institute (U.S.) (Cancer Center Support (core) Grant P30-CA14051)John D. Proctor Foundation (Margaret A. Cunningham Immune Mechanisms in Cancer Research Fellowship Award)Howard Hughes Medical Institute (Investigator)Virginia and Daniel K. Ludwig Graduate Fellowshi
Applications of the CRISPR–Cas9 system in cancer biology
Full text linkThe prokaryotic type II CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats-CRISPR-associated 9) system is rapidly revolutionizing the field of genetic engineering, allowing researchers to alter the genomes of a large range of organisms with relative ease. Experimental approaches based on this versatile technology have the potential to transform the field of cancer genetics. Here, we review current approaches for functional studies of cancer genes that are based on CRISPR-Cas, with emphasis on their applicability for the development of next-generation models of human cancer
Strategies to Achieve Conditional Gene Mutation in Mice
Full text linkThe laboratory mouse is an ideal model organism for studying disease because it is physiologically similar to human and also because its genome is readily manipulated. Genetic engineering allows researchers to introduce specific loss-of-function or gain-of-function mutations into genes and then to study the resulting phenotypes in an in vivo context. One drawback of using traditional transgenic and knockout mice to study human diseases is that many mutations passed through the germline can profoundly affect development, thus impeding the study of disease phenotypes in adults. New technology has made it possible to generate conditional mutations that can be introduced in a spatially and/ or temporally restricted manner. Mouse strains carrying conditional mutations represent valuable experimental models for the study of human diseases and they can be used to develop strategies for prevention and treatment of these diseases. In this article, we will describe the most widely used DNA recombinase systems used to achieve conditional gene mutation in mouse models and discuss how these systems can be employed in vivo
In Vivo Delivery of Lenti-Cre or Adeno-Cre into Mice Using Intranasal Instillation
Full text linkLung cancer remains the leading cause of cancer deaths among both men and women, with a lower rate of survival than both breast and prostate cancer. Development of the Cre/lox system and improved mouse models have allowed researchers to gain a better understanding of human disease, including lung cancer. Through the viral delivery of Cre, gene function in adult mice can be precisely studied at a specific developmental stage or in a specific cell/tissue type of choice. This protocol describes how to produce adenovirus-Cre precipitate. Using this adeno-Cre (or lentivirus-Cre), Cre can be expressed in mouse lungs. The virus is delivered by intranasal instillation
Tissue-specific p19[superscript Arf] regulation dictates the response to oncogenic K-ras
No full textThe ability of oncogenes to engage tumor suppressor pathways represents a key regulatory mechanism that can limit the outgrowth of incipient tumor cells. For example, in a number of settings oncogenic Ras strongly activates the Ink4a/Arf locus, resulting in cell cycle arrest or senescence. The capacity of different cell types to execute tumor suppressor programs following expression of endogenous K-ras[superscript G12D] in vivo has not been examined. Using compound mutant mice containing the Arf[superscript GFP] reporter and the spontaneously activating K-ras[superscript LA2] allele, we have uncovered dramatic tissue specificity of K-ras[superscript G12D]-dependent p19[superscript Arf] up-regulation. Lung tumors, which can arise in the presence of functional p19[superscript Arf], rarely display p19[superscript Arf] induction. In contrast, sarcomas always show robust activation, which correlates with genetic evidence, suggesting that loss of the p19[superscript Arf]-p53 pathway is a requisite event for sarcomagenesis. Using constitutive and inducible RNAi systems in vivo, we highlight cell type-specific chromatin regulation of Ink4a/Arf as a critical determinant of cellular responses to oncogenic K-ras. Polycomb-group complexes repress the locus in lung tumors, whereas the SWI/SNF family member Snf5 acts as an important mediator of p19[superscript Arf] induction in sarcomas. This variation in tumor suppressor induction might explain the inherent differences between tissues in their sensitivity to Ras-mediated transformation.National Institutes of Health (U.S.) (Grant 5-U01-CA84306)National Cancer Institute (U.S.) (Cancer Center Support Core Grant P30-CA14051
Conditional mouse lung cancer models using adenoviral or lentiviral delivery of Cre recombinase
No full textThe development of animal models of lung cancer is critical to our understanding and treatment of the human disease. Conditional mouse models provide new opportunities for testing novel chemopreventatives, therapeutics and screening methods that are not possible with cultured cell lines or xenograft models. This protocol describes how to initiate tumors in two conditional genetic models of human non-small cell lung cancer (NSCLC) using the activation of oncogenic K-ras alone or in combination with the loss of function of p53. We discuss methods for sporadic expression of Cre in the lungs through engineered adenovirus or lentivirus, and provide a detailed protocol for the administration of the virus by intranasal inhalation or intratracheal intubation. The protocol requires 1–5 min per mouse with an additional 30–45 min to set-up and allow for the recovery of mice from anesthesia. Mice may be analyzed for tumor formation and progression starting 2–3 weeks after infection.Howard Hughes Medical InstituteNational Cancer Institute (U.S.) (Cancer Center Support Grant)Massachusetts Institute of Technology. Ludwig Center for Molecular Oncolog
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