Elucidating and targeting epigenetic oncogenic networks in pancreatic cancer

描述（由申请人提供）：表观遗传机制介导正常细胞和癌症细胞身份的遗传控制。通过使用系统生物学方法，研究人员发现，KDM2B（一种含有jumonji结构域的组蛋白去甲基化酶，与细胞衰老和体细胞重编程的旁路有关）在人类PDAC中显着过表达，其水平随着疾病等级和分期而增加，在转移中表达最高。KDM2B沉默可使PDAC细胞系丧失上皮分化的致瘤性，而KDM2B过表达与KRASG12D在小鼠模型中以jumonji依赖的方式促进PDAC的形成。功能增益和功能丧失实验结合全基因组基因表达和染色质免疫沉淀研究表明，KDM2B通过调节发育途径和诱导代谢重编程来驱动致瘤性。尽管PDAC的特点是遗传病变数量明确，但药理学上针对这些途径的努力尚未成功。相比之下，参与PDAC的表观遗传网络在分子水平上知之甚少，并作为潜在的治疗靶点进行了探索。我建立了新的基因工程小鼠模型，有条件地消融和过表达KDM2B。我建议使用睡美人转座子介导的插入突变系统进行前向遗传筛选，以确定体内与KDM2B合作驱动胰腺癌发展的致癌网络。考虑到组蛋白甲基化的可逆性和Jumonji结构域的重要性，我建议使用高通量筛选技术发现KDM2B的小分子抑制剂，并在体外和体内测试其有效性。本研究旨在为胰腺癌表观遗传学领域提供进一步的见解，通过在体内鉴定和测试新的分子靶点，促进对驱动肿瘤发生的分子机制的理解，并为PDAC中正在进行的测序工作提供潜在癌症驱动突变的丰富资源进行交叉比较分析。

DESCRIPTION (provided by applicant): Epigenetic mechanisms mediate heritable control of cell identity in normal cells and cancer. By using a system biology approach it has been discovered that KDM2B, a Jumonji-domain containing histone demethylase implicated in bypass of cellular senescence and somatic cell reprogramming, is markedly overexpressed in human PDAC, with levels increasing with disease grade and stage, and highest expression in metastases. KDM2B silencing abrogates tumorigenicity of PDAC cell lines exhibiting loss of epithelial differentiation, whereas KDM2B overexpression cooperates with KRASG12D to promote PDAC formation in mouse models in Jumonji-dependent manner. Gain and loss-of-function experiments coupled to genome-wide gene expression and chromatin immunoprecipitation studies revealed that KDM2B drives tumorigenicity by regulating developmental pathways and inducing metabolic reprogramming. Although PDAC is characterized by a well-defined number of genetic lesions, efforts to pharmacologically target those pathways have been unsuccessful. In contrast, the epigenetic networks involved in PDAC are poorly understood at the molecular level and explored as potential therapeutic targets. I generated new genetically engineered mouse models to conditionally ablate and overexpress KDM2B. I propose to conduct a forward genetic screen using the Sleeping Beauty transposon-mediated insertional mutagenesis system to identify oncogenic networks that cooperate with KDM2B in vivo to drive pancreatic cancer development. Given the reversibility of histone methylation and the importance of the Jumonji domain, I propose to use high throughput screening technologies to discover small molecule inhibitors of KDM2B and test their efficacy in vitro and in vivo. This proposal aims to provide further insights into the field of epigenetics of pancreatic cancer, facilitate the understanding of molecular mechanism(s) that drive oncogenesis through identification and testing new molecular targets in vivo, and provide a rich resource of potential cancer driving mutations for cross-comparative analyses with ongoing sequencing efforts in PDAC.