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，迫切需要针对这些患者的新治疗策略。此次修订的竞争性更新提案的创新性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）调节人PC细胞的增殖和侵袭，这为PDX-1赋予了新的重要作用。有了这个新的作用，PDX-1可以作为PC治疗的分子靶点。我们建议在这项修订后的竞争性续期补助金中：1）扩大PDX-1谱的定义，以包括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谱，包括独立队列，以及3）将PDX-1谱与其如何指导PC小鼠模型中四种基于PDX-1的疗法的多个周期的选择相关联。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（RIP-TK）在小鼠PC细胞中的病毒胸苷激酶表达，可以使用PET和光学成像在PC细胞中检测到9-（4-（18 F）氟-3-羟甲基丁基）鸟嘌呤（18 F-FHBG）的稳定双标记类似物，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谱指导基于PDX-1的疗法的选择。具体目标一：以确定a）是否可以使用QPCR、蛋白质印迹和量子点去卷积成像和图像分析来验证PC的2个组群中PDX- 1表达水平的预后能力，B）是否使用DNA测序来验证PC中存在PDX-1遗传变异，以及c）人PC细胞系的增殖和侵袭的调节是否受到PDX-1表达水平和/或PDX-1遗传变异的影响。具体目标二：为了确定a）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疗法的基于PDX-1的疗法是否对使用病毒和非病毒递送系统的PC小鼠模型中的PC具有有效的细胞消融作用，B）PDX-1谱在每个周期后改变，从而指导治疗的选择，以及c）治疗诱导的胰源性（3型）小鼠中的糖尿病是暂时的，最终恢复治疗前的PDX-1谱、胰岛激素水平和胰岛形态，并且糖尿病可以用胰岛素和/或胰多肽给药治疗。具体目标三：以确定a）在具有不同PDX-1表达水平的PC细胞系中使用RIP-TK检测vTK表达的成像剂是否可以使用用于microPET成像的18 F-FHBG和/或用于光学成像和断层摄影术的双标记类似物进行验证，和B）对基于PDX-1的治疗的成像响应取决于PDX-1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。该提案的创新性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）调节人类PC细胞，这为PDX-1赋予了新的重要作用。初步数据支持PDX-1是PC的治疗靶点的假设，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展。

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.