Clinical Significance of Pancreatic Cancer Differentiation and Dedifferentiation

 描述(申请人提供)：侵袭性胰腺癌(PDA)是一种致命的疾病。虽然某些遗传和表观遗传改变多年来已广为人知，但到目前为止，这还没有导致有效的预防和/或治疗方式。我们的研究目标是确定基因表达的驱动变化，这些变化可以用来开发有效的策略来控制PDA的分化和进展。我们以前的研究表明，转录因子KLF4在侵袭性PDA中显著降低，这种失调促进了PDA生物学，而Panins并没有表现出KLF4的显著降低。与此形成鲜明对比的是，我们最近的研究显示，与PAINS相比，侵袭性PDA中miR-152低表达/DNMT1高表达是一致的。将miR-152-DNMT1-KLF4通路与动脉导管未分化/去分化联系起来，对于了解动脉导管未分化的进展具有重要意义。我们推测，miR-152表达下调导致DNMT1过度表达和KLF4下调，从而导致PDA去分化表型的获得，即从Panins转变为侵袭性PDA。因此，miR-152信号的激活和/或恢复可以抑制Panins的进展。为了验证我们的假设，我们提出了三个具体的目标：(1)确定PDA分化的临床意义及其受KLF4高甲基化的调节；(2)确定DNMT1在PDA分化中的因果作用及其潜在的调控机制；(3)确定靶向miR-152-DNMT1-KLF4信号通路在PDA治疗干预中的作用。这三个新的具体目标与临床相关问题、使用临床材料的机械证实和翻译验证，得到了我们各自的初步数据的支持，并可以使用我们独特的研究资源进行独立测试，但它们高度相关，相互支持。我们建议的研究将利用MD Anderson提供的独特资源，包括我们收集的大量PDA标本和小鼠模型。鉴于我们将揭示miR-152/DNMT1/KLF4的重要作用，我们预计这些研究的完成将为PDA进展的分子遗传学基础和鉴定 分子靶点设计有效的干预策略。从长远来看，我们的研究还可能导致进一步研究介导这一新的miR-152/DNMT1/KLF4信号通路失调的分子机制，并可能将我们的发现转化为开发有效的预防和治疗策略来控制PDA的进展。

 DESCRIPTION (provided by applicant): Invasive pancreatic cancer (PDA) is a lethal disease. While certain genetic and epigenetic alterations have been well known for years, to date this has not resulted in useful preventive and/or therapeutic modalities. Our research goal is to identify driving alterations in gene expression that can be utilized to develop effective strategie to control PDA differentiation and progression. Our previous studies have demonstrated that transcription factor KLF4 is drastically decreased in invasive PDA and this dysregulation critically promotes PDA biology, whereas PanINs do not exhibit substantially reduced KLF4 expression. In sharp contrast, our recent study has shown a consistent miR-152 underexpression/DNMT1 overexpression in invasive PDA as compared to that in PanINs. Causally linking miR-152-DNMT1-KLF4 pathway to PDA differentiation/dedifferentiation is highly significant in understanding PDA progression. We postulate that downregulation of miR-152 expression causes DNMT1 overexpression and KLF4 downregulation and consequential acquisition of de-differentiated phenotype in PDA, i.e., a switch from PanINs to invasive PDA. Therefore, activation and/or restoration of miR-152 signaling could attenuate PanINs progression. To test our hypothesis, we propose three specific aims: (1) To determine the clinical significance of PDA differentiation and its regulation by KLF4 hypermethylation; (2) To determine the causal role of DNMT1 in PDA differentiation and potential mechanisms underlying its dysregulation; and (3) Determine the utility of targeting miR-152-DNMT1-KLF4 signaling pathway for therapeutic intervention of PDA. These three novel specific aims with clinical relevant questions, mechanistic substantiation using clinical materials and translational validation, are supported by our respective preliminary data and can be tested independently using our unique research resources, yet they are highly interrelated and support one another. Our proposed studies will take advantage of the unique resources available at MD Anderson, including our large collection of PDA specimens and mouse models. Given the important role of miR-152/DNMT1/KLF4 we will uncover, we predict that completion of these studies will provide insightful information for the molecular genetic basis of PDA progression and for identification of molecular targets to design effective intervention strategies. In the long term, our study also ca lead to further investigation of the molecular mechanisms mediating dysregulation of this novel miR-152/DNMT1/KLF4 signaling pathway, and potential translation or our findings into developing effective preventive and therapeutic strategies to control PDA progression.