Mitophagy-Mediated Cell Death in Mammary Tumorigenesis

项目摘要 背景：超过90%的癌症是由于癌细胞转移到远处和重要器官所致。 癌症死亡率。鉴于这一极高的死亡率， 消除转移癌细胞或根除初期癌细胞的新治疗方法 在转移扩散之前。肿瘤进展和转移的一个重要屏障是失巢凋亡，一种半胱天冬酶， 由整合素介导的与细胞外基质（ECM）的附着丧失诱导的依赖性细胞死亡程序。 然而，已经清楚的是，ECM脱离可以诱导失巢凋亡独立机制， 损害细胞活力。更具体地说，我们发现非癌上皮细胞的脱落 ECM中的细胞引发活性氧（ROS）水平的显著升高， 细胞存活在一个失巢凋亡独立的方式。对细胞变化的理解有助于 在ECM脱离期间ROS的升高仍然是基本的，癌细胞利用的策略是， ECM脱离期间的战斗ROS没有得到充分的探索。因此，这些点代表了重要的 本资助提案旨在解决的知识差距。机械信息识别 ECM脱离、ROS和细胞存活之间的联系可以为治疗药物的设计提供靶点。 旨在特异性消除ECM脱离的癌细胞的方法;这一结果可能具有显著的 对转移性疾病患者的影响。 目的/假设：总的来说，我们的初步研究揭示了一种新的细胞死亡机制（ 肿瘤抑制功能），损害ECM-脱离细胞的生存力：诱导线粒体自噬 这是RIPK 1信号传导的结果。因此，这些数据激发了我们的中心假设，即RIPK 1- ECM脱离期间介导的线粒体自噬作为乳腺癌进展的屏障发挥作用。 具体目的I：阐明ECM-脱离促进RIPK 1依赖性 线粒体自噬并引发细胞死亡。 具体目的II：评估RIPK 1介导的线粒体自噬拮抗体内肿瘤形成的能力 并评估抗氧化剂抑制作为一种新的策略，以限制肿瘤发生的癌症是缺乏 RIPK 1介导的线粒体自噬 预期成果：完成这些研究后，我们将积累大量 关于ECM脱离、RIPK 1线粒体自噬和细胞死亡之间关系的机制知识。 因此，这些研究的完成将揭示关于癌细胞的基本生物学见解， ECM分离期间的存活率，最终可能导致治疗方法的发展 来限制乳腺癌细胞的扩散。

Project Summary Background: The metastasis of cancerous cells to distant and vital organs is responsible for in excess of 90% of cancer mortalities. Given this extraordinarily high mortality rate, there is a significant need for the development of novel therapeutic approaches that either eliminate metastatic cancer cells or eradicate incipient cancer cells prior to metastatic dissemination. An important barrier to tumor progression and metastasis is anoikis, a caspase- dependent cell death program induced by loss of integrin-mediated attachment to extracellular matrix (ECM). However, it has become clear that ECM-detachment can induce anoikis-independent mechanisms that can compromise cell viability. More specifically, we have discovered that detachment of non-cancerous epithelial cells from ECM triggers a significant elevation in the levels of reactive oxygen species (ROS) which compromises cell survival in an anoikis-independent fashion. The understanding of the cellular changes that contribute to the elevation of ROS during ECM-detachment remains rudimentary and the strategies utilized by cancer cells to combat ROS during ECM-detachment are insufficiently explored. Therefore, these points represent significant knowledge gaps that this grant proposal aims to address. Discernment of mechanistic information regarding the links between ECM-detachment, ROS, and cell survival could provide targets for the design of the therapeutic approaches aimed at specifically eliminating ECM-detached cancer cells; an outcome that may have significant impact for patients with metastatic disease. Objective/hypothesis: In aggregate, our preliminary studies have unveiled a novel cell death mechanism (with a tumor suppressive function) that compromises the viability of ECM-detached cells: the induction of mitophagy as consequence of RIPK1 signaling. As such, these data have motivated our central hypothesis that RIPK1- mediated mitophagy during ECM-detachment functions as a barrier to breast cancer progression. Specific Aim I: To elucidate the molecular mechanism by which ECM-detachment promotes RIPK1-dependent mitophagy and initiates cell death. Specific Aim II: To assess the capacity of RIPK1-mediated mitophagy to antagonize tumor formation in vivo and to evaluate antioxidant inhibition as a novel strategy to limit tumorigenesis in cancers that are deficient in RIPK1-mediated mitophagy Anticipated Outcomes: Following the completion of these studies, we will have accumulated significant mechanistic knowledge regarding the relationship between ECM-detachment, RIPK1 mitophagy, and cell death. Thus, the completion of these studies will unveil fundamental biological insights regarding cancer cell survival during ECM-detachment that may ultimately lead to the development of therapeutic approaches to limit the dissemination of breast cancer cells.