New transgenic animal model to study pancreatic cancer

描述（由申请人提供）：胰腺癌是一种侵袭性疾病，目前没有有效的治疗方法，预后不良。为这种总是致命的疾病开发改进的疗法的能力将显著受益于动物模型，该动物模型在患者中重现疾病并允许非侵入性监测和跟踪胰腺导管腺癌（PDAC）的发展和进展。研究PDAC生物学和治疗的研究人员广泛使用KPC转基因小鼠，其含有激活的K-ras癌基因和胰腺中一个或两个p53肿瘤抑制基因的缺失。这种动物模型遵循人类疾病的过程，从而提供了一个有用的和潜在的预测系统，用于评估治疗干预。然而，与人类患者一样，这种小鼠在肿瘤发展的时间和动力学方面表现出很大的变异性，有效监测肿瘤和转移性生长具有挑战性。我们的研究试图纠正这种情况，并开发一种PDAC模型，允许更准确的分期和评价比现有的KPC小鼠模型的治疗。我们测试了这样的假设，即在转基因小鼠的所有组织中整合驱动荧光素酶报告基因（CCN 1-Luc基因构建体）的癌症选择性启动子可以作为CCN 1-Luc小鼠与KPC小鼠杂交后通过生物发光成像（BLI）非侵入性成像原发性肿瘤和转移的手段。已经用几种双转基因动物CCN 1-Luc-KPC小鼠获得了原理证明，表明施用Escherin允许通过BLI检测原发性肿瘤和转移，如通过分离器官中的荧光和免疫组织化学（IHC）所证实的。这些结果具有创新性和重要性，支持使用这种独特的双转基因小鼠模型（称为“PanMetView”或PMV小鼠）进行进一步研究，以评估PDAC的发展和转移进展，以及治疗对这些过程的影响。PMV小鼠模型的特征研究将在我们资助的具体目标1中进行。为了确认PMV小鼠用于评估治疗干预的效用，我们选择了一种新的治疗方法，其涉及递送聚肌苷酸-聚胞苷酸（pIC），一种激活免疫系统的合成dsRNA，并且当使用聚乙烯亚胺（PEI）[pIC]PEI施用到癌细胞的胞质溶胶中时，引起细胞凋亡和毒性自噬。初步研究表明，[pIC]PEI在体外以及体内多种免疫缺陷动物模型中显示出强效的胰腺抗肿瘤作用，包括异种移植和人胰腺癌细胞的准原位给药。[pIC]PEI在PMV小鼠中的治疗功效的原理证明将在我们资助的特定目标2中进行测试。我们的研究的成功完成将在如何使用转基因小鼠研究PDAC方面具有变革性意义，该转基因小鼠作为一种全球性技术具有广泛的应用，用于产生双转基因小鼠，以跟踪其他癌症模型的发展，进展和治疗。

DESCRIPTION (provided by applicant): Pancreatic cancer is an aggressive disease without currently effective therapies and with poor prognosis. The ability to develop improved therapies for this invariably fatal disease would benefit significantly from animal models that recapitulate the disease in patients and allow for non-invasively monitoring and following pancreatic ductal adenocarcinoma (PDAC) development and progression. Investigators studying PDAC biology and therapy extensively use the KPC transgenic mouse, which contains an activated K-ras oncogene and deletion of one or both p53 tumor suppressor genes in the pancreas. This animal model follows the course of the human disease and thereby provides a useful and potentially predictive system for evaluating therapeutic intervention. However, as with human patients, this mouse shows great variability in the timing and kinetics of tumor development and effectively monitoring tumor and metastatic growth is challenging. Our research seeks to remedy this situation and develop a PDAC model permitting more accurate staging and evaluation of therapy than the existing KPC mouse model. We tested the hypothesis that integrating a cancer-selective promoter driving the luciferase reporter gene, a CCN1-Luc gene construct, in all tissue of a transgenic mouse could serve as a means of imaging primary tumors and metastases non-invasively by bioluminescence imaging (BLI) following crossing of the CCN1-Luc mouse with the KPC mouse. Proof-of-principle has been obtained with several double transgenic animals, CCN1-Luc-KPC mice, indicating that administering luciferin allows for detection of primary tumors and metastases by BLI, as confirmed by fluorescence in isolated organs and immunohistochemistry (IHC). These results are innovative and significant, supporting further studies using this unique double transgenic mouse model, called "PanMetView" or PMV mice, to evaluate PDAC development and progression to metastasis, and the potential of therapy to impact on these processes. Studies characterizing the PMV mouse model will be performed in Specific Aim 1 of our grant. To confirm utility of the PMV mice for evaluating therapeutic intervention, we have chosen a novel therapeutic approach that involves delivery of polyinosinic-polycytidylic acid (pIC), a synthetic dsRNA that activates the immune system and when administered into the cytosol of cancer cells, using polyethyleneimine (PEI), [pIC]PEI, causes apoptosis and toxic autophagy. Preliminary studies indicate that [pIC]PEI displays potent pancreatic antitumor effects in vitro as well as in multiple immune deficient animal models in vivo, including xenografts and quasi-orthotopic administration of human pancreatic cancer cells. Proof-of-principle for therapeutic efficacy of [pIC]PEI in the PMV mice will be tested in Specific Aim 2 of our grant. Successful completion of our studies will be transformative in how PDAC is studied using transgenic mice with wide applications as a global technique for generating double transgenic mice to follow development, progression and therapy in other cancer models.