Project 1: Defining Mechanisms of MICAL-dependent Pancreatic Cancer Cell Migration

项目摘要/摘要--项目1 胰腺管腺癌(PDAC)每12分钟夺走一名美国人的生命， 不成比例地影响非洲裔美国人和西班牙裔患者，他们的发病率更高 与非西班牙裔白人患者相比，死亡率更高。由于PDAC的发生率相对较低，即使 在高危人群中，筛查是不可行的。因此，改善结果需要改善 了解PDAC生物学，以指导有效治疗的开发。在这里，合伙少年派的 PDAC生物学和细胞生物物理特性建模方面的互补专业知识汇聚在一起，研究 PDAC细胞迁移和转移的机制，这是该患者群体死亡的主要原因。 洛伊实验室专注于通过在PDAC与 正常的胰腺。他们假设，定义细胞特性的超级增强子相关基因将 成为PDAC的有效治疗靶点。一个差异乙酰化的增强子区域被映射到 MICAL2基因，编码黄素单加氧酶。这种蛋白质驱动F-肌动蛋白解聚，即在 胞浆可以重组肌动蛋白肌球蛋白机制，用于迁移和响应外部机械和 生化信号。MICAL2还在核肌动蛋白动力学与血清反应因子之间发挥作用 (SRF)转录。肌钙蛋白相关转录因子(MTRF)是SRF的共同激活因子；当核 肌动蛋白解聚是由MICAL2诱导的，球状肌动蛋白是核输出的靶点，释放mtrF到 结合SRF并激活对细胞黏附和迁移至关重要的基因的转录。PDAC细胞的研究 提示沉默MICAL2的表达会损害细胞的迁移和转移。 Katira实验室与恩格勒博士的团队合作报告称，细胞粘附性是一种 转移潜能的生物物理标志物，以及粘附性和伸缩性都能使附着性趋化， 细胞的迁移能力，不受刚度梯度的影响。该项目的目标是定义MICAL2如何 影响粘附性和趋化性的特性，以及它如何调节特性，不仅仅是癌症的特性 而不是通过基因表达调控肿瘤微环境。我们假设MICAL2 细胞自主和非细胞自主促进PDAC细胞侵袭转移 机械装置。我们将在三个具体目标上检验这一假说：1)确定MICAL2如何调节 胰腺癌细胞的黏附和多药趋化，2)决定MICAL2如何促进胰腺癌 细胞迁移和转移，以及3)决定MICAL2如何与来自癌症和间质细胞的信号有关 调节肿瘤微环境。作为一个假定的治疗靶点，我们的目标是确定MICAL2如何 在PDAC进展过程中，功能上调节细胞的迁移和转移能力。这一知识将是 了解如何以及何时在PDAC中针对MICAL2活动的关键。

PROJECT SUMMARY/ ABSTRACT – PROJECT 1 Pancreatic duct adenocarcinoma (PDAC) takes the life of an American approximately every 12 minutes and disproportionately affects African American and Hispanic patients, who experience higher rates of morbidity and mortality compared to non-Hispanic white patients. Since the incidence of PDAC is relatively modest, even among higher risk groups, screening is not feasible. Thus, improvements in outcomes require an improved understanding of PDAC biology to guide development of effective therapies. Here, the partnering PI’s complementary expertise in PDAC biology and modeling cellular biophysical properties converge to investigate mechanisms of PDAC cell migration and metastasis, the primary cause of death in this patient population. The Lowy laboratory focused on identifying therapeutic targets by performing unbiased discovery in PDAC vs. normal pancreas. They hypothesized that super enhancer associated genes, which define cell identity, would be effective therapeutic targets for PDAC. One differentially acetylated enhancer region was mapped to the MICAL2 gene, that encodes a flavin monooxygenase. This protein drives F-actin depolymerization, that in the cytosol can restructure the actin myosin machinery used to migrate and respond to external mechanical and biochemical signals. MICAL2 also plays a role in linking nuclear actin dynamics to serum response factor (SRF) transcription. Myocardin-related transcription factors (MTRFs) are co-activators of SRF; when nuclear actin depolymerization is induced by MICAL2, globular actin is targeted for nuclear export, freeing MTRF to bind SRF and activate transcription of genes important for cell adhesion and migration. Studies in PDAC cells reveal that silencing MICAL2 expression impairs cell migration and metastasis. The Katira laboratory in collaboration with Dr. Engler’s group have reported that cell adhesiveness serves as a biophysical marker for metastatic potential, and both adhesiveness and contractility enable adurotaxis, the ability of cells to migrate regardless of a stiffness gradient. To goal of this project is to define how MICAL2 influences properties of adhesiveness and durotaxis, and how it may regulate properties, not only of the cancer cell, but of the tumor microenvironment through regulation of gene expression. We hypothesize that MICAL2 promotes PDAC cell invasion and metastasis by cell autonomous and non-cell autonomous mechanisms. We will test this hypothesis in three specific aims; 1) Determine how MICAL2 modulates adherence and durotaxis in pancreatic cancer cells, 2) Determine how MICAL2 promotes pancreatic cancer cell migration and metastasis, and 3) Determine how MICAL2 related signaling from cancer an stromal cells modulates the tumor microenvironment. As a putative therapeutic target, our goal is to determine how MICAL2 functionally regulates cell migration and metastatic capacity during PDAC progression. This knowledge will be key to understanding how and when MICAL2 activity can be targeted in PDAC.