Integrin Regulation of Non-apoptotic Death in Breast Cancer

总结 本研究将探讨铁凋亡在上皮和癌生物学中的调节和作用。 铁凋亡涉及细胞内活性氧（ROS）的积累，导致细胞内铁代谢的失活。 脂质修复酶谷胱甘肽过氧化物酶4（GPX 4）和随之而来的脂质过氧化物的增加， 导致细胞死亡。获得的数据显示，细胞外基质（ECM）脱落的乳腺上皮和 乳腺癌细胞在缺乏α 6 β 4的情况下特异性地经历铁凋亡。此外，ECM分离的细胞， 在缺乏A6 B4的情况下，簇易于发生铁凋亡。相反，如果a6 b4，则单个细胞经历凋亡。 表达是枯竭的。a6 b4在ECM-分离细胞中发出抗铁毒性反应信号的能力 似乎依赖于富含F-肌动蛋白的细胞-细胞复合物，并且a6 b4可能使 这些复合物被称为“铁凋亡抗性复合物”。假设a6 b4 在这些条件下的信号传导缓冲了由于ECM引起的脂质过氧化的增加， 通过维持GPX 4（一种脂质过氧化物酶）的表达，使细胞脱离，从而避免铁凋亡。它 提出该机制涉及a6 b4信号传导稳定GPX 4 mRNA并阻止其表达的能力。 通过促进N6-甲基腺苷（m6 A）RNA去甲基化在应激条件下衰减。第一个目标将 研究a6 b4信号如何在ECM分离的细胞中激活及其在铁凋亡形成中的作用 抵抗情结第二个目标将确定a6 b4信号传导影响GPX 4的稳定性， 其他mRNA对ECM脱离的反应。这一目标也将涉及到识别mRNA的光谱， 其在ECM脱离时通过m6 A-去甲基化而稳定。最后的目的将探讨的意义 使用小鼠模型研究乳腺癌中GPX 4的a6 b4调节和铁凋亡的逃避。这一目标将 涉及评估GPX 4对乳腺肿瘤发生和进展的贡献的无偏倚方法 通过在三阴性乳腺癌转基因小鼠模型中进行条件性缺失。对这些小鼠的分析 将能够评估GPX 4对肿瘤起始、生长和转移的贡献，包括 循环肿瘤细胞，以及其在体内逃避铁凋亡中的作用。小说和意料之外的 有待解决的假设有可能开辟一个具有重大意义的新的研究领域 我们对铁凋亡和肿瘤生物学的理解，这可能有助于设计和开发 阻止转移的疗法。 !

Summary This proposal will examine the regulation and role of ferroptosis in epithelial and carcinoma biology. Ferroptosis involves the accumulation of intracellular reactive oxygen species (ROS) leading to inactivation of the lipid repair enzyme glutathione peroxidase 4 (GPX4) and the consequent increase in lipid peroxides that causes cell death. Data obtained reveal that extracellular matrix (ECM)-detached mammary epithelial and breast carcinoma cells undergo ferroptosis specifically in the absence of a6b4. Also, ECM-detached cells that cluster are prone to ferroptosis in the absence of a6b4. In contrast, single cells undergo apoptosis if a6b4 expression is depleted. The ability of a6b4 to signal an anti-ferroptotic response in ECM-detached cells appears to be dependent on F-actin-rich, cell-cell complexes and that a6b4 may nucleate the formation of these complexes, which have been termed ‘ferroptosis resistance complexes’. It is hypothesized that a6b4 signaling under these conditions buffers an increase in lipid peroxidation that occurs as a result of ECM detachment by maintaining the expression of GPX4, a lipid peroxidase, enabling the evasion of ferroptosis. It is proposed that the mechanism involves the ability of a6b4 signaling to stabilize GPX4 mRNA and prevents its decay in stress conditions by promoting N6-methyladenosine (m6A) RNA de-methylation. The first aim will investigate how a6b4 signaling is activated in ECM-detached cells and its role in the formation of ferroptosis resistance complexes. The second aim will determine that a6b4 signaling impacts the stability of GPX4 and other mRNAs in response to ECM-detachment. This aim will also involve identifying the spectrum of mRNAs that are stabilized by m6A-de-methylation upon ECM-detachment. The final aim will investigate the significance of a6b4 regulation of GPX4 and evasion of ferroptosis in breast cancer using mouse models. This aim will involve an unbiased approach to assessing the contribution of GPX4 to breast tumorigenesis and progression by conditional deletion in a transgenic mouse model of triple-negative breast cancer. Analysis of these mice will enable an assessment of the contribution of GPX4 to tumor initiation, growth and metastasis, including circulating tumor cells, and its role in the evasion of ferroptosis in vivo. The novel and unanticipated hypotheses to be addressed have the potential to open a new field of investigation with significant implications for our understanding of both ferroptosis and tumor biology that could benefit the design and development of therapies to impede metastasis. !