Current methods in mouse models of pancreatic cancer (original) (raw)
Related papers
Modeling pancreatic cancer in mice for experimental therapeutics
Biochimica et Biophysica Acta (BBA) - Reviews on Cancer
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy that is characterized by early metastasis, low resectability, high recurrence, and therapy resistance. The experimental mouse models have played a central role in understanding the pathobiology of PDAC and in the preclinical evaluation of various therapeutic modalities. Different mouse models with targetable pathological hallmarks have been developed and employed to address the unique challenges associated with PDAC progression, metastasis, and stromal heterogeneity. Over the years, mouse models have evolved from simple cell line-based heterotopic and orthotopic xenografts in immunocompromised mice to more complex and realistic genetically engineered mouse models (GEMMs) involving multi-gene manipulations. The GEMMs, mostly driven by KRAS mutation(s), have been widely accepted for therapeutic optimization due to their high penetrance and ability to recapitulate the histological, molecular, and pathological hallmarks of human PDAC, including comparable precursor lesions, extensive metastasis, desmoplasia, perineural invasion, and immunosuppressive tumor microenvironment. Advanced GEMMs modified to express fluorescent proteins have allowed cell lineage tracing to provide novel insights and a new understanding about the origin and contribution of various cell types in PDAC pathobiology. The syngeneic mouse models, GEMMs, and target-specific transgenic mice have been extensively *
2012
Pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease despite tremendous scientific efforts. Numerous trials have failed to improve the outcome on this deadliest of all major cancers. Potential causes include a still insufficient understanding of key features of this cancer and imperfect preclinical models for identification of active agents and mechanisms of therapeutic responses and resistance. Modern genetically engineered mouse models of PDAC faithfully recapitulate the genetic and biological evolution of human PDAC, thereby providing a potentially powerful tool for addressing tumour biological issues as well as strategies for early detection and assessment of responses to therapeutic interventions. Here, the authors will discuss opportunities and challenges in the application of genetically engineered mouse models for translational approaches in pancreatic cancer and provide a non-exhaustive list of examples with already existing or future clinical relevance.
Genetically-engineered mouse models for pancreatic cancer: Advances and current limitations
World journal of clinical oncology, 2011
Recently, there has been significant progress in the development of genetically-engineered mouse (GEM) models. By introducing genetic alterations and/or signaling alterations of human pancreatic cancer into the mouse pancreas, animal models can recapitulate human disease. Pancreas epithelium-specific endogenous Kras activation develops murine pancreatic intraepithelial neoplasia (mPanIN). Additional inactivation of p16, p53, or transforming growth factor-β signaling, in the context of Kras activation, dramatically accelerates mPanIN progression to invasive pancreatic ductal adenocarcinoma (PDAC) with abundant stromal expansion and marked fibrosis (desmoplasia). The autochthonous cancer models retain tumor progression processes from pre-cancer to cancer as well as the intact tumor microenvironment, which is superior to xenograft models, although there are some limitations and differences from human PDAC. By fully studying GEM models, we can understand the mechanisms of PDAC formation...
Deploying Mouse Models of Pancreatic Cancer for Chemoprevention Studies
Cancer Prevention Research, 2010
With the advent of mouse models that recapitulate the cellular and molecular pathology of pancreatic neoplasia and cancer, it is now feasible to recruit and deploy these models for the evaluation of various chemopreventive and/or anticancer regimens. The highly lethal nature of pancreatic ductal adenocarcinoma (PDAC) makes multiple areas of research a priority including assessment of compounds that prevent or suppress the development of early lesions that can transform into PDAC. Currently, there are over a dozen models available, which range from homogeneous preneoplastic lesions with remarkable similarity to human pancreatic intraepithelial neoplasms (PanINs) to models with a more heterogeneous population of lesions including cystic papillary and mucinous lesions. The molecular features of these models may also vary in a manner comparable to the differences observed in lesion morphology, and so navigating the route of model selection is not trivial. Yet, arming the community of cancer investigators with a repertoire of models and the guidance to select relevant models that fit their research themes promises to produce findings that will have clinical relevance.
PloS one, 2013
Pancreatic cancer (PC) remains one of the most lethal human malignancies with poor prognosis. Despite all advances in preclinical research, there have not been significant translation of novel therapies into the clinics. The development of genetically engineered mouse (GEM) models that produce spontaneous pancreatic adenocarcinoma (PDAC) have increased our understanding of the pathogenesis of the disease. Although these PDAC mouse models are ideal for studying potential therapies and specific genetic mutations, there is a need for developing syngeneic cell lines from these models. In this study, we describe the successful establishment and characterization of three cell lines derived from two (PDAC) mouse models. The cell line UN-KC-6141 was derived from a pancreatic tumor of a Kras G12D ;Pdx1-Cre (KC) mouse at 50 weeks of age, whereas UN-KPC-960 and UN-KPC-961 cell lines were derived from pancreatic tumors of Kras G12D ;Trp53 R172H ;Pdx1-Cre (KPC) mice at 17 weeks of age. The cancer mutations of these parent mice carried over to the daughter cell lines (i.e. Kras G12D mutation was observed in all three cell lines while Trp53 mutation was observed only in KPC cell lines). The cell lines showed typical cobblestone epithelial morphology in culture, and unlike the previously established mouse PDAC cell line Panc02, expressed the ductal marker CK19. Furthermore, these cell lines expressed the epithelial-mesenchymal markers Ecadherin and N-cadherin, and also, Muc1 and Muc4 mucins. In addition, these cell lines were resistant to the chemotherapeutic drug Gemcitabine. Their implantation in vivo produced subcutaneous as well as tumors in the pancreas (orthotopic). The genetic mutations in these cell lines mimic the genetic compendium of human PDAC, which make them valuable models with a high potential of translational relevance for examining diagnostic markers and therapeutic drugs.
What We Have Learned About Pancreatic Cancer From Mouse Models
Gastroenterology, 2012
P ancreatic ductal adenocarcinoma (PDA) is one of the most devastating malignancies worldwide. A total of 43,140 new cases (ranked 10th) and 36,800 deaths (ranked 4th) from pancreatic cancer were estimated to occur in the United States during 2010, with an overall 5-year survival rate of just 6%. 1 This dire clinical situation exists despite recent advances in our understanding of the genetics and biology of PDA. Most patients with advanced PDA either do not respond, or respond only transiently, to systemic chemotherapy and radiotherapy. Although a few patients with PDA undergo potentially curative surgery, most PDAs ultimately recur. Over the past decade, genetically engineered mouse models (GEMMs) of PDA have been created. We describe how these models have enabled a detailed investigation of PDA biology, including tumor development and progression, and the role of inflammation and the tumor microenvironment. We also discuss how mouse models of PDA are being used to develop new therapeutic and diagnostic approaches. Conditional Kras Models of Pancreatic Cancer Although approaches to generate mouse models of pancreatic cancer started in the late 1980s, 2,3 the GEMM that most closely resembles human disease was established in 2003. 4 This model is based on the LSL-Kras G12D strain of mice, which has an endogenous, conditional Kras G12D mutant allele silenced by a floxed transcriptional STOP cassette (Lox-Stop-Lox or LSL) inserted upstream of the targeted Exon1. Removal of this LSL by directing expression of Cre recombinase with adenoviral-Cre allows expression of oncogenic Kras G12D in the lung. 5 Likewise, LSL-Kras G12D mice crossed with mice that express Cre recombinase under the control of the Pdx1 or Ptf1a/P48 promoters develop pancreatic ductal cancer. 4 Such compound mutant mice (Pdx1-Cre;LSL-Kras G12D and Ptf1a/P48-Cre;LSL-Kras G12D) develop a spectrum of preneoplasms with complete penetrance, termed pancreatic intraepithelial neoplasias (PanINs) (Figure 1). As in patients, PanINs develop in these mice along a specific pattern of progression, and a subset of older mice develop PDA. The PanINs that develop in mice resembled those of patients in that they express mucins, the epithelial protein cytokeratin-19, and components of signaling pathways that include Cyclooxygenase (Cox)-2, MMP-7, and Hes1. 4 This GEMM supported a PanIN-to-PDA model of pancreatic cancer progression that was first proposed by Hruban et al. 6,7 In this model, activating mutations in the Kras gene, which are found in more than 90% of human PDAs, initiate PDA formation by inducing development of low-grade PanIN lesions. Human PanINs are believed to progress to PDA following the acquisition of additional epigenetic and genetic somatic alterations, including inactivation or point mutation of p16/CDKN2A (Ͼ95%), TP53 (50%-75%), and the transforming growth factor (TGF)- pathway components DPC4/SMAD4 (55%), TGFRI (Ͻ5%), and TGFRII (Ͻ5%). 8-11 Studies of GEMMs of PDA incorporating these additional mutant alleles have supported the genetic basis of progression. These GEMMs included compound mutant mice that express a conditionally oncogenic Kras allele in the pancreatic compartment, in combination with the monoallelic and biallelic loss of the p16 Ink4a /p19 Arf and p53 genes, 12,13 the concomitant expression of dominant-negative forms of p53 (that contain Li Fraumeni point mutations), 14 or the ablation of the type II TGF- receptor (Tgfbr2). 15 These compound mutant mice develop invasive and metastatic PDA, with some characteristic features associated with each genotype, and can be used to determine the molecular mechanisms by which different subtypes of PDA develop and investigate differences in responses to therapeutic strategies 16 (Figure 1). In addition to PanINs, which are the most common and best characterized pancreatic preneoplasms, several GEMMs develop cystic preneoplasms, including intraductal papillary mucinous neoplasms (IPMNs) and mu
Pancreatology, 2019
Pancreatic ductal adenocarcinoma (PDAC) is among the dangerous human cancers, is the 10th highly prevalent cancer, and the fourth sole cause of cancer-related mortality in the United States of America. Notwithstanding the significant commitment, the forecast for people with this burden continues to have a five-year survival rate of just 4e6%. The most critical altered genes within PDAC consist of K-ras the proto-oncogene which is usually mutationally activated above 90% cases and tumor suppressors likeTrp53 are altered at 55%. To face the burden of pancreatic ductal adenocarcinoma, a variety of genetically engineered pancreatic cancer mice models have been created over the last past years. These models have distinctive features and are not all appropriate for preclinical studies. In this review, we focus on differences between two mice models K-ras LSL.G12D/þ ;Pdx-1-Cre(KC) and K-ras LSL.G12D/þ ; Trp53 R172H/þ ; Pdx-1-Cre(KPC) in terms of their modeling biology and their clinical relevance.
A rapid in vivo screen for pancreatic ductal adenocarcinoma therapeutics
Disease Models & Mechanisms, 2015
Pancreatic ductal adenocarcinoma (PDA) is the fourth leading cause of cancer-related deaths in the United States, and is projected to be second by 2025. It has the worst survival rate among all major cancers. Two pressing needs for extending life expectancy of affected individuals are the development of new approaches to identify improved therapeutics, addressed herein, and the identification of early markers. PDA advances through a complex series of intercellular and physiological interactions that drive cancer progression in response to organ stress, organ failure, malnutrition, and infiltrating immune and stromal cells. Candidate drugs identified in organ culture or cell-based screens must be validated in preclinical models such as KIC (p48 Cre ;LSL-Kras G12D ;Cdkn2a f/f) mice, a genetically engineered model of PDA in which large aggressive tumors develop by 4 weeks of age. We report a rapid, systematic and robust in vivo screen for effective drug combinations to treat Krasdependent PDA. Kras mutations occur early in tumor progression in over 90% of human PDA cases. Protein kinase and G-protein coupled receptor (GPCR) signaling activates Kras. Regulators of Gprotein signaling (RGS) proteins are coincidence detectors that can be induced by multiple inputs to feedback-regulate GPCR signaling. We crossed Rgs16::GFP bacterial artificial chromosome (BAC) transgenic mice with KIC mice and show that the Rgs16::GFP transgene is a Kras G12D-dependent marker of all stages of PDA, and increases proportionally to tumor burden in KIC mice. RNA sequencing (RNA-Seq) analysis of cultured primary PDA cells reveals characteristics of embryonic progenitors of pancreatic ducts and endocrine cells, and extraordinarily high expression of the receptor tyrosine kinase Axl, an emerging cancer drug target. In proof-ofprinciple drug screens, we find that weanling KIC mice with PDA treated for 2 weeks with gemcitabine (with or without Abraxane) plus inhibitors of Axl signaling (warfarin and BGB324) have fewer tumor initiation sites and reduced tumor size compared with the standard-of-care treatment. Rgs16::GFP is therefore an in vivo reporter of PDA progression and sensitivity to new chemotherapeutic drug regimens such as Axltargeted agents. This screening strategy can potentially be applied to identify improved therapeutics for other cancers.
Challenges and advances in mouse modeling for human pancreatic tumorigenesis and metastasisan
Pancreatic cancer is critical for developed countries, where its rate of diagnosis has been increasing steadily annually. In the past decade, the advances of pancreatic cancer research have not contributed to the decline in mortality rates from pancreatic cancer—the overall 5-year survival rate remains about 5% low. This number only underscores an obvious urgency for us to better understand the biological features of pancreatic carcinogenesis, to develop early detection methods, and to improve novel therapeutic treatments. To achieve these goals, animal modeling that faithfully recapitulates the whole process of human pancreatic cancer is central to making the advancements. In this review, we summarize the currently available animal models for pancreatic cancer and the advances in pancreatic cancer animal modeling. We compare and contrast the advantages and disadvantages of three major categories of these models: (1) carcinogen-induced; (2) xenograft and allograft; and (3) genetically engineered mouse models. We focus more on the genetically engineered mouse models, a category which has been rapidly expanded recently for their capacities to mimic human pancreatic cancer and metastasis, and highlight the combinations of these models with various newly developed strategies and cell-lineage labeling systems.