Therapeutic Targeting of Autophagy-Dependent Cancer

项目摘要 线粒体是细胞中的关键细胞器，调节许多过程，包括能量产生和细胞增殖。 发信号。许多癌细胞依赖于功能性线粒体进行细胞存活。线粒体 因此，体内平衡是至关重要的，并且受到严格的调节。受损的线粒体被一种选择性的 自噬的一种形式，称为线粒体自噬，其中完整的线粒体被自噬体吞噬 然后与溶酶体融合以促进降解。以前已经表明，癌细胞是 依赖于核心自噬调节因子如ATG 7和FIP 200生存，但这些细胞中的罕见细胞 种群可以在失去这一核心途径的情况下生存下来。来自高度自噬的ATG 7 KO细胞 依赖性细胞转变为不依赖自噬。尽管缺乏典型的线粒体自噬， 自噬缺陷细胞仍然可以降解线粒体并维持线粒体功能。最近有 发表了一篇文章，说细胞在失去自噬后存活下来， MDV可以直接与溶酶体融合以维持线粒体稳态。MDV较多的细胞 依赖于它们来维持线粒体功能和整体生存。MDV的研究非常不足，但这 这项研究表明，它们可能是癌细胞中潜在的新靶点。这里提出的工作将包括更多 机制研究，以了解MDV是如何调节的。这些囊泡的唯一已知调节剂是 内吞调节分选连接蛋白，SNX 9，但它如何调节MDV的形成是未知的。这些研究将 包括结构-功能分析，以剖析SNX 9中每个结构域的具体作用， 调节MDV的形成和运输以及其在线粒体内稳态和整体细胞中的作用 生存SNX 18与SNX 9同源，可以补偿其在胞吞作用中的作用。这些研究将测试 SNX 18在MDV中也很重要的假设。该项目的一个重要目标是培训和 西耶娜导师在这些研究中，她将学习新技术，包括分子克隆，流式细胞术， 和线粒体功能测定等。她还将学习如何发展自己的假设， 设计具有关键控制的实验，以推动她自己的项目向前发展。她的下一个职业目标是获得博士学位 关注癌症差异的癌症生物学。该项目将为她提供必要的工具， 技术以及额外的课程工作，以帮助她准备博士课程。她还将出席全国 像ABRCMS这样的会议。这个项目旨在帮助她成功过渡到研究生 2023年秋季的计划。

PROJECT SUMMARY Mitochondria are key organelles in the cell and regulate many processes including energy production and cell signaling. Many cancer cells are dependent on functional mitochondria for cell survival. Mitochondrial homeostasis is therefore critical and is tightly regulated. Damaged mitochondria are turned over by a select form of autophagy, known as mitophagy, where an intact mitochondrion is engulfed by an autophagosome which then fuses with a lysosome to facilitate degradation. It has been previously shown that cancer cells are dependent on core autophagy regulators like ATG7 and FIP200 for survival, but rare cells from these populations can survive loss of this core pathway. The ATG7 KO cells that were derived from highly autophagy dependent cells switched to become autophagy independent. Despite a lack of canonical mitophagy, the autophagy deficient cells can still degrade mitochondria and maintain mitochondrial function. It was recently published that cells that survive loss of autophagy can instead form small mitochondrial derived vesicles (MDVs) that can directly fuse with lysosomes to maintain mitochondrial homeostasis. Cells with more MDVs are dependent on them for mitochondrial function and overall survival. MDVs are highly understudied, but this work suggests they could be a potential new target in cancer cells. The work proposed here will include more mechanistic studies to understand how MDVs are regulated. The only known regulator of these vesicles is the endocytosis-regulating sorting nexin, SNX9, but how it regulates MDV formation is unknown. These studies will include structure-function analysis to dissect the specific roles of each domain within SNX9 to determine how it regulates MDV formation and trafficking as well as its role in mitochondrial homeostasis and overall cell survival. SNX18 is homologous to SNX9 and can compensate for its role in endocytosis. These studies will test the hypothesis that SNX18 is also important in MDVs. A significant goal of this project is also to train and mentor Sienna. During these studies she will learn new techniques including molecular cloning, flow cytometry, and mitochondrial function assays among others. She will also learn how to develop her own hypotheses and design experiments with critical controls to drive her own project forward. Her next career goal is to get a PhD in cancer biology with a focus on cancer disparities. This project will provide her with the necessary tools and techniques as well additional course work to help prepare her for PhD programs. She will also attend national meetings like ABRCMS. This project is designed to help her make the successful transition into graduate programs in the Fall of 2023.