Protein Kinase D in oncogenic oxidative stress signaling

项目/摘要 胰腺导管腺癌（PDAC）可能是迄今为止已知的最具侵袭性的癌症， 5年生存率最低。PDAC中增加的生长因子信号传导和K-ras突变导致 以升高的速率产生活性氧物质（ROS）。ROS作为第二信使， 细胞内信号级联，其诱导并维持致癌表型。很少有人知道的 保护性信号级联，由氧化应激激活并调节肿瘤细胞存活。具有 了解这些保护性信号传导机制非常重要，因为它们的调节可能允许 使ROS体内平衡倾斜，使癌细胞对化疗诱导的细胞死亡敏感。是 我们假设氧化应激通过激活蛋白激酶D介导肿瘤细胞存活。 具体来说，我们假设ROS介导的PKD信号通过线粒体传递， 并且由该途径激活的PKD通过转录因子FOXO 3a调节存活。我们 进一步假设PKD的药理学抑制增加了肿瘤细胞的敏感性 ROS介导的细胞死亡为了验证这一点，我们将：确定蛋白激酶D是如何被招募到 线粒体对ROS的反应（特异性目的1）;将肿瘤抑制因子FOXO 3a表征为细胞抑制因子。 ROS活化PKD（特异性目标2）靶向和表征新型PKD抑制剂及其对 癌症治疗（具体目标3）。成功完成本提案将有助于理解 PDAC细胞中ROS和PKD介导的保护性信号传导。它将表明，在响应生长因子，K- ras或其他ROS诱导剂，作为PKD激活机制的第一步，PKD位于 线粒体通过DAG结合。它将进一步剖析PKD在肿瘤细胞存活中的作用，通过鉴定FOXO 3a作为 一种新的PKD靶点。最后，我们将描述新的PKD抑制化合物的敏化价值， 胰腺癌细胞对ROS和化疗诱导的细胞死亡的反应。总的来说，我们的结果将提供 为胰腺癌患者开发新的和更有效的治疗策略奠定了基础。

PROJECT/SUMMARY ABSTRACT Pancreatic ductal adenocarcinoma (PDAC) is probably the most aggressive form of cancer known to date with the lowest overall 5-year survival rate. Increased growth factor signaling and K-ras mutations in PDAC lead to the generation of reactive oxygen species (ROS) at elevated rates. ROS act as second messengers in intracellular signaling cascades, which induce and maintain the oncogenic phenotype. Little is known about the protective signaling cascades that are activated by oxidative stress and regulate tumor cell survival. It is of great importance to understand these protective signaling mechanisms since their modulation may allow tipping the balance in ROS homeostasis to sensitize cancer cells to chemotherapeutics-induced cell death. It is our hypothesis that oxidative stress mediates tumor cell survival by activating Protein Kinase D. Specifically, we hypothesize that ROS-mediated PKD signaling is transmitted through the mitochondria and that PKD activated by this pathway regulates survival via the transcription factor FOXO3a. We further hypothesize that the pharmacological inhibition of PKD increases the sensitivity of tumor cells to ROS-mediated cell death. To test this we will: Determine how Protein Kinase D is recruited to the mitochondria in response to ROS (Specific Aim 1); Characterize the tumor suppressor FOXO3a as a cellular target for ROS-activated PKD (Specific Aim 2) and Characterize novel PKD inhibitors and their value for cancer therapy (Specific Aim 3). Successful completion of this proposal will contribute to the understanding of ROS- and PKD-mediated protective signaling in PDAC cells. It will show that in response to growth factors, K- ras or other inducers of ROS, as a first step in the PKD activation mechanisms, PKD is located to the mitochondria via DAG binding. It will further dissect PKD's role in tumor cell survival by identifying FOXO3a as a novel PKD target. Finally, we will characterize novel PKD-inhibiting compounds for their value in sensitizing pancreatic cancer cells to ROS- and chemotherapeutics-induced cell death. Overall our results will provide the basis for the development of novel and more potent therapeutic strategies for pancreatic cancer patients.