Redox Modification and Targeting of Mutant KRas in Cancer

摘要 KRAS的致癌突变是胰腺癌进展和生长的标志性事件，几乎是胰腺癌的一个重要标志。 普遍致命的疾病。致癌KRAS等位基因表达导致代谢变化和细胞信号传导改变 这两种途径都刺激细胞内活性氧（ROS）的产生。ROS驱动增加 胰腺癌前病变的形成和进展通过上调生存和生长因子信号传导 途径。尽管ROS失调是癌细胞增殖的核心，如KRas诱导的细胞增殖所例示的，但ROS失调是癌细胞增殖的核心。 尽管ROS依赖性瘤形成的机制与肿瘤发生密切相关，但其机制仍然知之甚少。阐发 和表征的氧化还原依赖的'开关'，支持ROS驱动的肿瘤已经严重 由于缺乏直接的方法来检查其天然细胞中的氧化半胱氨酸修饰， 环境我们的实验室已经通过开发化学蛋白质组学方法解决了这一挑战 用于原位检测氧化还原信号传导和应激的原型蛋白质生物标志物，称为半胱氨酸次磺酸 （Cys-SOH或S-亚磺酰基化）。在这里，我们采用最先进的方法来实现我们的主要目标：1）现场- KRasmut依赖性半胱氨酸基氧化还原“开关”的特异性映射和表征， 胰腺癌的发展，和2）检查肿瘤发生的潜力和药理学影响， 在突变体KRasG 12 C中获得的半胱氨酸处的氧化修饰。该项目的成功完成将确定 氧化半胱氨酸修饰作为通过突变KRas引发胰腺癌的过程的整体特征。 它还将描绘KRasG 12 C的氧化还原活性硫醇的氧化修饰与其分子结构之间的关系。 致瘤效力和设计用于靶向该突变体的小分子的功效。它还将确定以下方面的作用： 氧化还原在KRasG 12 C的致瘤效力和设计用于靶向该突变体的小分子的功效中的作用。在 除了KRas本身，本研究中确定的氧化还原途径的分子组分可能代表了 胰腺癌早期诊断和治疗的新生物标志物和药物靶点。

ABSTRACT Oncogenic mutation of KRAS is a signature event in progression and growth of pancreatic cancer, an almost universally fatal disease. Oncogenic KRAS allele expression leads to metabolic changes and altered cellular signaling pathways that both stimulate the production of intracellular reactive oxygen species (ROS). Increases in ROS drive formation and progression of pancreatic precancerous lesions by upregulating survival and growth factor signaling pathways. Despite ROS dysregulation being central to cancer cell proliferation, as exemplified by KRas-induced tumorigenesis, the mechanisms underlying ROS-dependent neoplasia remain very poorly understood. Elucidation and characterization of the redox-dependent ‘switches’ that support ROS-driven neoplasia have been severely hampered by the lack of direct methods to examine oxidative cysteine modifications in their native cellular environment. Our laboratory has addressed this challenge through the development of a chemoproteomic approach for in situ detection of the prototypical protein biomarker of redox signaling and stress, known as cysteine sulfenic acid (Cys-SOH or S-sulfenylation). Here, we apply state-of-the-art methods to accomplish our major objectives of: 1) site- specific mapping and characterization of KRasmut-dependent cysteine-based redox ‘switches’ that support development of pancreatic cancer, and 2) examining the tumorigenic potential and pharmacological impact of oxidative modification at the acquired cysteine in mutant KRasG12C. Successful completion of this project will identify oxidative cysteine modification as an integral feature of processes that initiate pancreatic cancer through mutant KRas. It will also delineate the relationship between oxidative modification of the redox-active thiol of KRasG12C to its tumorigenic potency and the efficacy of small-molecules designed to target this mutant. It will also define the role of redox in tumorigenic potency of KRasG12C and the efficacy of small-molecules designed to target this mutant. In addition to KRas itself, the molecular components of redox pathways identifying during this study may represent new biomarkers and drug targets for the early diagnosis and treatment of pancreatic cancer.