Inhibition of pancreatic carcinogenesis via targeting c-Raf and sEH

描述（申请人提供）：本项目的意义在于开发一种通过靶向c-Raf和sEH预防高致死性胰腺癌的有效药物。早期发现和预防对降低胰腺癌的死亡率至关重要。突变型Kras是人类胰腺癌发生中涉及的最常见和最早的分子事件;并且在小鼠中使用突变型Kras引发的肿瘤发生，已经证明c-Raf是Kras引发的肿瘤发生所需的，并且敲除c-Raf阻断Kras引发的癌症发展。慢性胰腺炎是胰腺癌的一个公认的危险因素。在Pdx 1-Cre/LSL-KrasG 12 D小鼠（称为PanKras）中突变型Kras启动的胰腺肿瘤发生中，雨蛙肽诱导的胰腺炎增强了恶性进展。除了胰腺炎，突变型Kras与突变型p53（第二种最常见的遗传改变）合作，主要通过协同调节ERK-MAPK和NF-kB，导致小鼠胰腺癌的发展。抗炎激素通过促炎可溶性环氧化物水解酶（sEH）快速失活。我们的初步数据显示：1）96%（27/28）和90%（27/30）的人胰腺癌样品分别显示出sEH和p-c-Raf的明显过表达; 2）我们的新型c-Raf/sEH双重抑制剂t-CUPM在PanKras小鼠中对胰腺炎和mPanIN形成表现出强抑制作用。我们的假设是，c-Raf和sEH在突变型Kras启动的胰腺癌发生中起关键作用，并通过胰腺炎或突变型p53增强;靶向这两种酶一起是胰腺癌的一种新的和相关的预防策略。本研究拟从三个方面来验证这一假设：1）研究c-Raf/sEH双重抑制剂t-CUPM、sEH抑制剂t-AUCB和Raf抑制剂Raf 265/索拉非尼对突变型Kras启动的胰腺炎增强的PanKras小鼠癌变的影响; 2）确定使用抑制剂或基因敲除阻断突变型Kras激活的c-Raf是否抑制突变型Kras-p53相互作用和Pdx 1-p53中的恶性进展。p53 R172小鼠的胰腺炎模型; 3）在PanKras小鼠中使用sEH基因敲除的方法来确定sEH在胰腺炎和癌变中的作用。本研究的成功不仅将使我们能够证明c-Raf和sEH在胰腺癌发生中的作用，而且还将建立t-CUPM作为抑制胰腺癌发展的新药物的意义。

DESCRIPTION (provided by applicant): The significance of this project is to develop an efficient agent for the prevention of highly lethal pancreatic cancer through targeting both c-Raf and sEH. Early detection and prevention is of great importance to reduce the mortality of pancreatic cancer. Mutant Kras is the most common and earliest molecular event involved in human pancreatic carcinogenesis; and using mutant Kras-initiated tumorigenesis in mice, it has been demonstrated that c-Raf is required for Kras-initiated tumorigenesis and knockout c-Raf blocks Kras- initiated cancer development. Chronic pancreatitis is a well-recognized risk factor of pancreatic cancer. In mutant Kras-initiated pancreatic tumorigenesis in Pdx1-Cre/LSL-KrasG12D mice (called PanKras), caerulein- induced pancreatitis enhances malignant progression. In addition to pancreatitis, mutant Kras cooperates with mutant p53 (the second most common genetic alteration) leading to pancreatic cancer development in mice, mainly via synergistically regulating ERK-MAPK and NF-kB. Anti-inflammatory EETs are quickly inactivated by pro-inflammatory soluble epoxide hydrolase (sEH). Our preliminary data showed that 1) 96% (27/28) and 90% (27/30) of human pancreatic adenocarcinoma samples displayed a distinct over-expression of sEH and p-c-Raf, respectively, and 2) our novel dual c-Raf/sEH inhibitor t-CUPM exhibited strong inhibitory effect on pancreatitis and mPanIN formation in PanKras mice. Our hypothesis is that c-Raf and sEH play key roles in pancreatic carcinogenesis initiated by mutant Kras and enhanced by pancreatitis or mutant p53; and targeting these two enzymes together is a novel and relevant preventive strategy for pancreatic cancer. Three specific aims are proposed to test this hypothesis: 1) to determine the effects of c-Raf/sEH dual inhibitor t-CUPM, sEH inhibitor t- AUCB and Raf inhibitor Raf265/sorafenib on mutant Kras-initiated and pancreatitis-enhanced carcinogenesis in PanKras mice; 2) to determine whether blocking mutant Kras-activated c-Raf using inhibitors or gene knockout suppresses mutant Kras-p53 interaction and malignant progression in Pdx1-KrasG12D-p53R172 mice; and 3) to determine the role of sEH in pancreatitis and carcinogenesis using the approach of sEH gene knockout in PanKras mice. Successfulness of the proposed study will not only lead us to demonstrate the role of c-Raf and sEH in pancreatic carcinogenesis, but also to establish a significance of t-CUPM as a novel agent for inhibiting the pancreatic cancer development.