PDX-1 is a Therapeutic Target for Pancreatic Cancer

描述(申请人提供)：转移性胰腺癌(PC)患者在确诊后存活4-11个月，因此迫切需要一种新的治疗策略。这一修订后的竞争性更新方案的创新发现是，胰岛素转录因子胰腺十二指肠同源盒转录因子(PDX-1)调控人PC细胞的增殖和侵袭，这赋予了PDX-1一个新的重要角色。有了这个新的作用，PDX-1可以作为PC治疗的分子靶点。在这项修订的竞争性更新拨款中，我们建议1)扩展PDX-1配置文件的定义，以包括PDX-1表达水平和PDX-1基因变异，2)分析更多PC样本中的PDX-1配置文件，包括一个独立的队列，以及3)将PDX-1配置文件与其如何指导PC小鼠模型中四种基于PDX-1的疗法的多周期选择有关。初步数据还显示，利用大鼠胰岛素启动子-胸苷激酶基因疗法(RIP-TK)在小鼠PC细胞中的病毒胸苷激酶表达可以通过9-(4-(18F)氟-3-羟甲基丁基)鸟嘌呤(18F-FHBG)稳定的双标记类似物(18F-FHBG)的PET和光学成像在PC细胞中检测到，因此，可以对治疗反应进行成像。假设：我们的假设是PC中的PDX-1图谱指导基于PDX-1的治疗方案的选择。具体目的1：通过定量聚合酶链式反应、免疫印迹和量子点去卷积成像和图像分析，确定PDX-1在两组PC中的表达水平是否具有预测预后的能力；b)通过DNA测序证实PC中存在PDX-1基因变异；c)PDX-1表达水平和/或PDX-1基因变异影响PC细胞系增殖和侵袭的调节。具体目的二：确定a)通过静脉注射PDX-1 shRNA和/或2)大鼠胰岛素启动子片段-胸苷激酶和更昔洛韦基因治疗是否对使用病毒和非病毒载体的PC小鼠模型具有有效的细胞清除作用；b)每个周期后PDX-1谱发生变化，从而指导治疗选择；c)治疗诱导的小鼠胰源性(3型)糖尿病是暂时的，最终恢复治疗前PDX-1的谱、胰岛激素水平和胰岛形态，并且糖尿病可用胰岛素和/或胰多肽治疗。具体目的三：确定a)使用RIP-TK检测不同PDX-1表达水平的PC细胞系中vTK表达的显像剂是否可以使用18F-FHBG进行microPET成像和/或光学成像和断层扫描的双标记类似物进行验证，以及b)基于PDX-1的治疗的成像反应取决于PDX-1的特征。公共卫生相关性：转移性胰腺癌(PC)患者在确诊后存活4-11个月，因此迫切需要一种新的治疗策略。这一建议的创新发现是胰岛素转录因子胰腺十二指肠同源盒转录因子(PDX-1)调控人PC细胞，这赋予了PDX-1一个新的重要角色。初步数据支持PDX-1是PC的治疗靶点的假设，这可能是这种可怕疾病患者的一个有意义的进步。

DESCRIPTION (provided by applicant): Patients with metastatic pancreatic cancer (PC) survive 4-11 months following diagnosis, therefore, a new strategy for therapy for these patients is urgently needed. The innovative discovery of this revised competitive renewal proposal is that the insulin transcription factor pancreatic duodenal homeobox transcription factor (PDX-1) regulates proliferation and invasion of human PC cells, which assigns a new and important role for PDX-1. With this new role, PDX-1 could serve as a molecular target for PC therapy. We propose in this revised competitive renewal grant to 1) expand the definition of the PDX-1 profile to include both PDX-1 expression levels and PDX-1 genetic variation, 2) to analyze the PDX-1 profile in a much larger number of PC specimens, including an independent cohort, and 3) to relate the PDX-1 profile to how it might guide choice of multiple cycles of four PDX-1-based therapies in PC mouse models. Preliminary data also demonstrate that viral thymidine kinase expression using rat insulin promoter-thymidine kinase gene therapy (RIP-TK) in PC cells in mice can be detected in PC cells using PET and optical imaging with stable dual-labeled analogs of 9-(4-(18F) fluoro-3-hydroxymethylbutyl) guanine (18F-FHBG), therefore, response to therapy could be imaged. Hypothesis: Our hypothesis is that the PDX-1 profile in PC guides the choice of PDX-1-based therapies. Specific aim I: to determine whether a) the prognostic capability of expression levels of PDX- 1 in 2 cohorts of PC can be validated using QPCR, western blots and quantum dot deconvolution imaging and image analysis, b) PDX-1 genetic variation exists in PC using DNA sequencing and c) regulation of proliferation and invasion of human PC cell lines is influenced by PDX-1 expression levels and/or PDX-1 genetic variation. Specific aim II: to determine whether a) PDX-1 based therapies using 1) iv PDX-1 shRNA and/or 2) rat insulin promoter fragment-thymidine kinase and ganciclovir gene therapy have an effective cytoablative effect on PC in PC mouse models using viral and nonviral delivery systems, b) PDX-1 profile is altered after each cycle and thus guides choice of therapy and c) therapy-induced pancreatogenic (type 3) diabetes in mice is temporal with ultimate restoration of the pre-treatment PDX-1 profile, islet hormone levels and islet morphology and that the diabetes can be treated with insulin and/or pancreatic polypeptide administration. Specific aim III: to determine whether a) imaging agents to detect vTK expression using RIP-TK in PC cell lines with varying PDX-1 expression levels can be validated using 18F-FHBG for microPET imaging and/or dual labeled analogues for optical imaging and tomography and b) the imaged response to PDX-1-based therapies is dependent upon the PDX-1 profile. PUBLIC HEALTH RELEVANCE: Patients with metastatic pancreatic cancer (PC) survive 4-11 months following diagnosis, therefore, a new strategy for therapy for these patients is urgently needed. The innovative discovery of this proposal is that the insulin transcription factor pancreatic duodenal homeobox transcription factor (PDX-1) regulates human PC cells, which assigns a new and important role for PDX-1. Preliminary data support the hypothesis that PDX-1 is a therapeutic target for PC, which could be a meaningful advance for patients with this horrible disease.