PDX-1 is a Therapeutic Target for Pancreatic Cancer

描述（由申请人提供）：转移性胰腺癌（PC）患者在诊断后存活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建议的创新发现是胰岛素转录因子胰十二指肠同源盒转录因子（PDX-1）调节人PC细胞的增殖和侵袭，这赋予了PDX-1新的重要作用。有了这个新的作用，PDX-1可以作为PC治疗的分子靶点。在这一修订后的竞争性更新资助中，我们建议：1)扩大PDX-1基因谱的定义，包括PDX-1表达水平和PDX-1遗传变异；2)分析更多PC标本中的PDX-1基因谱，包括一个独立的队列；3)将PDX-1基因谱与它如何指导PC小鼠模型中四种基于PDX-1的治疗方法的多个周期选择联系起来。初步数据还表明，使用大鼠胰岛素启动子-胸苷激酶基因治疗（riptk）在小鼠PC细胞中的病毒胸苷激酶表达可以通过PET和稳定的双标记9-（4-(18F)氟-3-羟甲基丁基）鸟嘌呤（18F- fhbg）的光学成像检测到，因此可以成像对治疗的反应。假设：我们的假设是PC患者的PDX-1特征指导了基于PDX-1的治疗方法的选择。具体目的1：通过QPCR、western blots和量子点反卷积成像及图像分析，确定a) PDX-1表达水平在2组PC患者中的预后能力，b)通过DNA测序确定PDX-1遗传变异在PC中是否存在，c) PDX-1表达水平和/或PDX-1遗传变异对人PC细胞系增殖和侵袭的调控是否有影响。具体目标二：为了确定a)基于PDX-1的治疗是否使用1)iv 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对使用病毒和非病毒递送系统的PC小鼠模型中的PC具有有效的细胞抑制作用，b)每个周期后PDX-1谱发生改变，从而指导治疗的选择，c)治疗诱导的小鼠胰源性（3型）糖尿病是暂时的，最终恢复了治疗前的PDX-1谱。胰岛激素水平和胰岛形态以及糖尿病可以用胰岛素和/或胰多肽治疗。具体目标III：确定a)在不同PDX-1表达水平的PC细胞系中使用riptk检测vTK表达的显像剂是否可以使用18F-FHBG进行微pet成像和/或光学成像和断层扫描的双标记类似物进行验证；b)基于PDX-1的治疗的成像反应取决于PDX-1的谱。公共卫生相关性：转移性胰腺癌（PC）患者在诊断后存活4-11个月，因此，迫切需要一种新的治疗策略。该提案的创新发现是胰岛素转录因子胰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新的重要作用。初步数据支持PDX-1是PC治疗靶点的假设，这对患有这种可怕疾病的患者来说可能是一个有意义的进步。

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.