Defining the roles of ERK MAPK in driving KRAS-mutant pancreatic cancer growth.

KRAS突变发生在约95%的胰腺导管腺癌（PDAC）中，对于支持PDAC至关重要 增长NCI已经确定开发抗KRAS疗法是该领域的四大目标之一。 在目前的方向中，通过RAF-MEK-ERK有丝分裂原激活的KRAS效应物信号传导的抑制剂是一种新的抑制剂。 蛋白激酶（MAPK）级联已经显示出前景。我们的实验室最近验证了ERK抑制剂作为 PDAC治疗的有前途的策略。然而，正常细胞毒性和肿瘤细胞先天/获得性抗性 可能会限制ERK抑制剂治疗的长期疗效。我的研究将挖掘两个未发表的组学数据 在我的实验室中生成的集合，以确定可能有助于克服这些限制的治疗策略。首先，在我的 目的1研究我已经评估了来自可药物化基因组RNAi筛选的数据，以鉴定调节 PDAC对ERK特异性抑制剂SCH 772984（ERKi）的敏感性。我选择评估其中一个热门歌曲，CHEK 1， 编码CHK 1丝氨酸/苏氨酸激酶。CHK 1是检查点介导的细胞周期阻滞所必需的， 激活DNA修复以响应DNA损伤。因此，CHK 1抑制剂更常规地用于治疗癌症。 与破坏DNA的抗癌药物结合。然而，我确定同时使用ERKi和 临床候选CHK 1抑制剂prexasertib在体外增强了对PDAC生长的抑制。我的研究会 确定将ERKi与prexasertib联合作为阻断KRAS的新策略的机制基础- 依赖PDAC生长。虽然我已经确定了抑制剂收敛阻断MYC癌基因 函数，我还将应用反相蛋白质阵列（RPPA）分析信号的无偏分析 转导活性/表达变化，以提供关于该组合疗法的另外的机制见解。我 还将在更严格的临床前模型中进一步评估该组合的潜在治疗价值， 在患者来源的类器官和原位PDAC小鼠模型中。其次，在我的目标2研究中，我评估了一个 RNA-seq数据集分析ERK依赖性转录组，目的是识别驱动ERK的基因- 依赖PDAC生长。我确定了20个上调和下调最多的基因，其中EGR 1是最重要的基因之一。 显著抑制基因。EGR 1是一种与癌症有关的转录因子， 致癌基因或肿瘤抑制基因，取决于评估的癌症类型。由于EGR 1表达是 抑制ERK抑制，我已经确定EGR 1调节MYC的表达，这是一个关键， 作为KRAS和ERK依赖的PDAC生长的一个贡献者，我假设EGR 1将是一个关键的组成部分， ERK介导的基因表达。与此同时，我还将使用20个下调基因的RNAi筛选， 建立一个更全面的识别基因，有助于ERK介导的PDAC的增长。我 拟议的研究将有助于推进针对ERK的PDAC治疗，并为我提供严格的 培训，以提高我的计算/生物信息学技能。

KRAS mutations occur in ~95% of pancreatic ductal adenocarcinoma (PDAC) and are essential to support PDAC growth. The NCI has identified the development of anti-KRAS therapies is one of four major goals for the field. Among current directions, inhibitors of KRAS effector signaling through the RAF-MEK-ERK mitogen-activated protein kinase (MAPK) cascade have shown promise. Our laboratory recently validated ERK inhibitors as a promising strategy for PDAC treatment. However, normal cell toxicity and tumor cell innate/acquired resistance will likely limit the long-term efficacy of ERK inhibitor therapy. My studies will mine two unpublished omics data sets generated in my lab, to identify therapeutic strategies that may help overcome these limitations. First, in my Aim 1 studies I have evaluated data from a druggable genome RNAi screen to identify genes that modulate PDAC sensitivity to the ERK-specific inhibitor SCH772984 (ERKi). I chose to evaluate one of the top hits, CHEK1, that encodes the CHK1 serine/threonine kinase. CHK1 is required for checkpoint-mediated cell cycle arrest and activation of DNA repair in response to DNA damage. As such, CHK1 inhibitors are more conventionally combined with DNA damaging anticancer drugs. Yet I determined that concurrent treatment with ERKi and the clinical candidate CHK1 inhibitor prexasertib enhanced suppression of PDAC growth in vitro. My studies will determine the mechanistic basis for combining ERKi with prexasertib as a novel strategy to block KRAS- dependent PDAC growth. While I have already identified inhibitor convergence on blocking MYC oncogene function, I will also apply reverse phase protein array (RPPA) analyses for an unbiased profiling of signal transduction activity/expression changes to provide addition mechanistic insight on this combination therapy. I will also further evaluate the potential therapeutic value of this combination in more rigorous preclinical models, in patient-derived organoids and orthotopic PDAC mouse models. Second, in my Aim 2 studies, I evaluated an RNA-seq data set profiling the ERK-dependent transcriptome with the goal of identifying genes that drive ERK- dependent PDAC growth. I identified the 20 most up- and down-regulated genes, with EGR1 one of the most significantly suppressed genes. EGR1 is a transcription factor that has been implicated in cancer, but as either an oncogene or tumor suppressor, depending on the cancer type evaluated. Since EGR1 expression is suppressed upon ERK inhibition, and I have determined that EGR1 regulates expression of MYC, a key contributor to KRAS- and ERK-dependent PDAC growth, I hypothesize that EGR1 will be a critical component of ERK mediated gene expression. In parallel, I will also use an RNAi screen with the 20 downregulated genes to establish a more comprehensive identification of genes that contribute to ERK-mediated PDAC growth. My proposed studies will help advance targeting ERK for PDAC treatment as well as provide me with rigorous training to enhance my computational/bioinformatics skills.