Prostate Cancer
Anthony R. Mundy, John M. Fitzpatrick, David E. Neal, Nicholas J. R. George in The Scientific Basis of Urology, 2010
To investigate the biology of prostate cancer, a number of models have been developed over the years. The three most widely used cell lines are LNCaP, an AR-positive epithelial prostate cancer cell line originating from a metastatic lymph node; PC-3, an AR-negative epithelial prostate cancer line originating from metastatic bone secondaries; and DU-145, an AR-negative epithelial prostate cancer line originating from metastatic brain secondaries (156–158). A wide range of murine in vivo experimental models are used to study tumor initiation, growth, and metastatic progression in prostate cancer. These models frequently employ gene “knockout,” “knock-in” or conditional regulation of individual gene expression (oncogenes, growth factors, cell cycle regulators), or combinations of genes (159, 160). These models are extremely useful in studying a variety of factors thought to affect the development and progression of prostate cancer (161). The recent ability to alter the expression of a specific gene in a single tissue cell type in a temporal fashion will greatly facilitate our studies to accurately model sporadic tumor formation for this disease in a whole animal (162).
Experimental perturbations to investigate cardiovascular physiology
Neil Herring, David J. Paterson in Levick's Introduction to Cardiovascular Physiology, 2018
Some of the issues with gene knockout models can be addressed with tissue- and time-specific knockouts. Tissue- specific knockout is achieved by incorporating locus of X-over P1 (loxP) sites either side of the gene of interest (floxed gene) using homologous recombination as described earlier. LoxP sites direct an enzyme called Cre recombinase that cuts and recombines sequences of DNA at these sites, thereby removing the sequence of DNA between them. The efficiency of the recombination tends to be lower the longer the length of DNA between the two loxP sites. The activity of Cre recom- binase can then be controlled by crossing the mouse with the floxed gene with another mouse expressing Cre recom- binase with a site- or cell-specific promoter as demonstrated in Figure 20.4. Examples of site/tissue-specific promoters with which Cre recombinase can be coupled include: synapsin (neuronal); PRSx8 (catecholaminergic neurons); alpha-myosin heav y chain (MHC; cardiac myocytes); smooth muscle MHC (smooth muscle); or tyrosine-protein kinase receptor Tie-2 (endothelial cells).
Gene Targeting Models of Epilepsy: Technical and Analytical Considerations
Steven L. Peterson, Timothy E. Albertson in Neuropharmacology Methods in Epilepsy Research, 2019
Given estimates that 30,000 genes are expressed in the mammalian brain,21 it is likely that the proliferation of new mutant mouse strains will include many that are relevant to the epilepsies. The first members of this new wave of epilepsy models illustrate the wide variety of genes that participate in the regulation of neuronal network excitability. It is likely that, in the future, an abundance of mechanisms involved in the regulation of excitability will be discovered. An advantage of pursuing this work in gene knockout models is that the genetic lesions are known, providing molecular points of reference for these studies. Furthermore, these models will provide candidate genes for studies aimed at uncovering the genetic bases of seizure susceptibility in humans.
A two-decade journey in identifying high mobility group box 1 (HMGB1) and procathepsin L (pCTS-L) as potential therapeutic targets for sepsis
Published in Expert Opinion on Therapeutic Targets, 2023
Jianhua Li, Cassie Shu Zhu, Li He, Xiaoling Qiang, Weiqiang Chen, Haichao Wang
Even though gene knockout strategies are widely used to elucidate potential roles of various signaling molecules in many diseases, cautions should always be exercised when using these genetic approaches to evaluate extracellular roles of various inflammatory mediators. For example, despite the aforementioned pathogenic role of HMGB1 in lethal sepsis [44], genetic disruption of HMGB1 expression unexpectedly renders animals more susceptible to both infections [116] and injuries [117], suggesting distinct roles of intracellular and extracellular HMGB1 in health and disease conditions [118]. Accordingly, we generated polyclonal antibodies against murine pCTS-L and used these pharmacological agents to further characterize the extracellular role of pCTS-L in experimental sepsis (Table 3). Anti-murine pCTS-L total IgGs (pAbs) conferred dose-dependent and significant protections against lethal sepsis when the first dose was given at 2 h post CLP (Table 3) [17]. Consistently, pCTS-L antigen affinity-purified IgGs of protective pAbs effectively abrogated the pCTS-L-induced production of both TLR4-dependent cytokines (e.g. IL-6) and chemokines (e.g. MIP-1γ, LIX, RANTES, and MCP-1), as well as the RAGE-dependent neutrophilic chemokines (such as KC/GRO-α and MIP-2/GRO-β). These findings have suggested that anti-pCTS-L pAbs conferred protection against lethal sepsis possibly by attenuating pCTS-L-induced hyperinflammation likely orchestrated by both TLR4 and RAGE receptors (Figure 1).
Getting a good view: in vitro imaging of platelets under flow
Published in Platelets, 2020
Oluwamayokun Oshinowo, Tamara Lambert, Yumiko Sakurai, Renee Copeland, Caroline E. Hansen, Wilbur A. Lam, David R. Myers
Animal models have long been advantageous in the study of both hemostasis and thrombotic disorders as the highly complex in vivo environment has increased our mechanistic understanding and knowledge of disease outcomes that are relevant to human health. Murine platelets have played a vital role in hemostasis and thrombosis studies because of their genetic and functional similarity to human platelets, despite differences in size and structure. As such, combining in vitro microfluidic studies with genetically modified animal models has played an imperative role in illuminating biochemical and/or biophysical adhesion and aggregation processes that are difficult to discern in vivo. Gene knockout models have provided insight into the importance of specific gene mutations and various mechanistic processes. Various microfluidic systems have leveraged gene knockouts in order to specifically decipher the importance of α2β1 and PAR4 [53], the importance of the PI3 K signaling pathway [54], and the importance of talin1 [55] in adhesion and aggregation of platelets to collagen and fibrinogen. Utilizing a commercial microfluidic system, an ADAMTS13 knockout mouse model has been used to better understand the pathophysiology of thrombotic thrombocytopenia purpura [56]. One study employed both knockout models of mice lacking GPVI and ex vivo inhibitors of αIIbβ3 and Src kinase to reveal the existence of two potential routes of platelet adhesion to collagen [57].
Efficacy and safety of sotagliflozin in treating diabetes type 1
Published in Expert Opinion on Pharmacotherapy, 2018
The sotagliflozin program differed from conventional pharmaceutical development in many ways. First, the utilization of a high-throughput approach to make knockout models is unique. The subsequent synthesis of inhibitors was efficient and led to many different molecules. Although the gene knockout approach was a major innovative advance, it was standard animal husbandry with careful observation of the heterozygous knockout mice which led to this conceptual breakthrough. Detailed and well-documented analysis of heterozygous mice led to the realization that partial inhibition of SGLT1 could be beneficial for glycemic control while avoiding the gastrointestinal effects seen in SGLT1 knockout mice and in humans with glucose-galactose malabsorption syndrome. As a result, Lexicon made a bold decision to pursue an agent which strongly inhibited SGLT2 but also had significant SGLT1 inhibitory effect. They launched initial safety studies in T2D, but then went in a new direction choosing T1D as their clinical indication.
Related Knowledge Centers
- Allele
- DNA Sequencing
- Gene Targeting
- Homologous Recombination
- Mutation
- Phenotype
- Zygosity
- Crispr Gene Editing
- Transcription Activator-Like Effector Nuclease
- Gene Knock-In