Role of necroptosis in colorectal cancer therapy

项目总结/摘要 本申请响应PA-17-440：细胞死亡途径在癌细胞存活和凋亡中的相互作用。 治疗抵抗（R 01）。结直肠癌（CRC）是美国癌症相关死亡的主要原因。 大多数CRC患者对治疗性治疗无反应。诱导程序性细胞死亡，广泛 称为细胞凋亡，是抗癌治疗的关键作用。最近的研究表明，程序性细胞死亡是 不限于半胱天冬酶依赖性凋亡，但包括坏死性凋亡，一种受调节的坏死性死亡形式 受受体相互作用蛋白1（RIP 1）、RIP 3和混合谱系激酶结构域样蛋白控制 （MLKL）。越来越多的证据表明，坏死性凋亡是一种防御机制， 致癌突变和病原体，并且可以被多种抗癌剂用来杀死癌细胞。 然而，坏死性凋亡的调控机制及其在肿瘤治疗中的作用还不清楚 明白尽管为恢复癌细胞中的凋亡进行了广泛的努力，但很少有人尝试 操纵坏死性凋亡以改善抗癌治疗，主要是由于对这种新的 定义的细胞死亡模式。我们的初步数据显示，CRCs中RIP 3表达的频繁缺失是由于CRCs中RIP 3表达的缺失导致的。 与不良临床结局相关。常见的化疗药物，如 5-氟尿嘧啶（5-FU）杀死RIP 3表达的CRC细胞亚群，并与稳健的抗肿瘤活性相关。 免疫反应我们还发现了一种新的坏死性凋亡途径，涉及BH 3-only Bcl-2家族蛋白 激活RIP 3和MLKL以响应于抗癌剂而引发坏死性凋亡。基于这些 研究结果，我们建议测试这一假设，ESTA/RIP 3介导的坏死性凋亡发挥了关键作用， 通过细胞内在和免疫效应确定CRC细胞亚群中的治疗反应， 可以有针对性地改善CRC治疗。目的1：定义在小鼠中诱导坏死性凋亡的背景和机制。 目的2：阐明坏死性凋亡在抗癌剂杀死CRC细胞中的功能作用。 目的3：确定是否可以使用操作坏死性凋亡来克服治疗性凋亡。 CRCs的抵抗力。拟议的研究将提供新的机制的见解，坏死诱导， CRC细胞中的抗癌剂。他们将阐明细胞凋亡和坏死性凋亡的相互作用如何介导 对抗癌治疗的反应，并为刺激坏死性凋亡以增强 肿瘤细胞杀伤和抗肿瘤免疫应答以改善CRC治疗。

PROJECT SUMMARY/ABSTRACT This application is responsive to PA-17-440: The Interplay of Cell Death Pathways in Cancer Cell Survival and Resistance to Therapy (R01). Colorectal cancer (CRC) is a leading cause of cancer-related deaths in the US. Most CRC patients are not responsive to therapeutic treatment. Induction of programmed cell death, widely known as apoptosis, is a key effect of anticancer therapy. Recent studies indicate that programmed cell death is not confined to caspase-dependent apoptosis, but includes necroptosis, a regulated form of necrotic death controlled by Receptor-Interacting Protein 1 (RIP1), RIP3, and Mixed Lineage Kinase Domain-Like protein (MLKL). Accumulating evidence suggests that necroptosis functions as a defensive mechanism against oncogenic mutations and pathogens, and can be utilized by a variety of anticancer agents to kill cancer cells. However, the regulatory mechanisms and functional role of necroptosis in anticancer therapy are poorly understood. Despite extensive efforts for restoring apoptosis in cancer cells, few attempts have been made to manipulate necroptosis for improving anticancer therapy, largely due to insufficient understanding of this newly defined cell death modality. Our preliminary data show that frequent loss of RIP3 expression in CRCs is associated with poor clinical outcomes. Necroptosis can be engaged by common chemotherapeutics such as 5-fluorouracil (5-FU) to kill a subset of CRC cells with RIP3 expression, and is associated with a robust antitumor immune response. We also identified a novel necroptosis pathway involving the BH3-only Bcl-2 family protein PUMA, which activates RIP3 and MLKL to initiate necroptosis in response to anticancer agents. Based on these findings, we propose to test the hypothesis that PUMA/RIP3-mediated necroptosis plays a critical role in determining therapeutic response in a subset of CRC cells via both cell intrinsic and immunologic effects, which can be targeted to improve CRC therapy. Aim 1: Define the context and mechanism of necroptosis induction in CRC cells by anticancer agents; Aim 2: Delineate the functional role of necroptosis in the killing of CRC cells by anticancer agents; and Aim 3: Determine if manipulating necroptosis can be used to overcome therapeutic resistance of CRCs. The proposed studies will provide new mechanistic insights on necroptosis induction by anticancer agents in CRC cells. They will clarify how the interplay of apoptosis and necroptosis mediates response to anticancer therapy, and provide proof-of-principle evidence for stimulating necroptosis to enhance tumor cell killing and antitumor immune response for improving CRC treatment.