New transgenic animal model to study pancreatic cancer

描述（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，预后差。对于这种不可避免的致命疾病，开发改进疗法的能力将显著受益于动物模型，这些模型可以概括患者的疾病，并允许无创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，这种小鼠在胰腺中含有活化的K-ras癌基因和一个或两个p53肿瘤抑制基因的缺失。该动物模型遵循人类疾病的进程，从而为评估治疗干预提供了有用的和潜在的预测系统。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可变性，有效监测肿瘤和转移性生长具有挑战性。我们的研究旨在纠正这种情况，并开发一种PDAC模型，比现有的KPC小鼠模型更准确地进行分期和评估治疗。我们验证了这样一个假设，即在转基因小鼠的所有组织中整合一个驱动荧光素酶报告基因（CCN1-Luc基因构建体）的癌症选择性启动子，可以作为CCN1-Luc小鼠与KPC小鼠杂交后，通过生物发光成像（BLI）无创成像原发性肿瘤和转移瘤的手段。在几种双转基因动物CCN1-Luc-KPC小鼠中获得了原理证明，表明给药荧光素可以通过BLI检测原发肿瘤和转移瘤，这一点得到了分离器官荧光和免疫组织化学（IHC）的证实。这些结果具有创新性和重要意义，支持进一步研究使用这种独特的双转基因小鼠模型，称为“PanMetView”或PMV小鼠，来评估PDAC的发展和转移过程，以及治疗对这些过程的潜在影响。表征PMV小鼠模型的研究将在我们拨款的Specific Aim 1中进行。为了确认PMV小鼠在评估治疗干预方面的效用，我们选择了一种新的治疗方法，包括传递多肌苷-多胞酸（pIC），一种激活免疫系统的合成dsRNA，当使用聚乙烯亚胺（PEI）， [pIC]PEI进入癌细胞的细胞质中时，导致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（包括异种移植和准原位给药人类胰腺癌细胞）中显示出强大的胰腺抗肿瘤作用。[pIC]PEI对PMV小鼠治疗效果的原理证明将在我们的拨款的特异性目标2中进行测试。我们的研究的成功完成将对如何使用转基因小鼠研究PDAC具有革命性的意义，作为一种广泛应用的全球技术，可以产生双转基因小鼠，以跟踪其他癌症模型的发育，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.