Integrin Regulation of Non-apoptotic Death in Breast Cancer

摘要 这项建议将研究铁性下垂在上皮和癌症生物学中的调节和作用。 铁下垂涉及细胞内活性氧簇(ROS)的积累，导致失活 脂质修复酶谷胱甘肽过氧化物酶4(Gpx4)和随之而来的过氧化脂质的增加 导致细胞死亡。获得的数据显示，细胞外基质(ECM)分离的乳腺上皮和 在缺乏A6b4的情况下，乳腺癌细胞会发生铁性下垂。此外，ECM分离的细胞 在缺乏A6B4的情况下，团簇容易发生铁性下垂。相反，如果a6b4基因被激活，单个细胞会发生凋亡。 表情耗尽了。细胞外基质分离细胞中a6b4信号转导抗铁链反应的能力 似乎依赖于富含F-肌动蛋白的细胞-细胞复合体，并且a6b4可能使 这些复合体被称为“抗铁下垂复合体”。据推测，A6B4 这些条件下的信号传递缓冲了ECM导致的脂质过氧化增加 通过维持脂质过氧化物酶Gpx4的表达，使铁下垂得以逃避。它 该机制涉及到a6b4信号稳定Gpx4信使核糖核酸并阻止其 在应激条件下通过促进N6-甲基腺苷(M6A)RNA去甲基化而腐烂。第一个目标是 探讨细胞外基质分离细胞中a6b4信号是如何被激活的及其在铁下垂形成中的作用 阻力复合体。第二个目标将确定a6b4信号影响Gpx4的稳定性和 其他对ECM脱离作出反应的mRNAs。这一目标还将涉及识别mRNAs的谱。 它们在细胞外基质脱离时通过m6A去甲基化而稳定。最终目标将调查其意义。 用小鼠模型研究乳腺癌中Gpx4的A6b4调节和铁下垂的逃避。这一目标将 采用公正的方法评估Gpx4在乳腺肿瘤发生和发展中的作用 通过在三阴性乳腺癌转基因小鼠模型中有条件地删除。对这些小鼠的分析 将能够评估Gpx4在肿瘤起始、生长和转移中的作用，包括 循环肿瘤细胞，及其在体内逃避铁性下垂中的作用。新奇而出乎意料的 有待解决的假设有可能开辟一个具有重大影响的新调查领域 对于我们对铁性下垂和肿瘤生物学的理解，有助于设计和开发 阻止转移的治疗方法。 好了！

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. !