Defining the Roles of Mitochondria in Breast Cancer Metastasis

项目摘要/摘要 线粒体执行许多重要功能，包括通过氧化磷酸化产生能量 (OXPHOS)及其功能障碍与包括癌症在内的病理学有关。有证据表明 转移是由具有独特生物学特性的稀有原发肿瘤细胞亚群播撒的。定义 这些独特的特性对于开发有效的治疗方法至关重要。使用单细胞RNA测序 (ScRNAseq)在三阴性乳腺癌患者来源的异种移植(PDX)模型上，我们产生了 肺内PDX微转移乳腺癌细胞及其相应原发肿瘤的首个单细胞图谱 细胞。我们发现肺微转移细胞和一小部分原发肿瘤细胞数量增加。 与乳腺癌相关的线粒体膜电位和先前未描述的基因上调 转移，包括NME1和RAN以及与OxPhos相关的基因。我们还发现了乳腺癌 细胞在功能上需要OxPhos在肺内播种。增加的OxPhos提供了更多的ATP用于 用于能量消耗过程的转移细胞，包括从三磷酸腺苷生产GTP用于激活 G蛋白及其下游通路与癌症的侵袭性有关。NME1基因编码 NME1二磷酸核苷激酶，利用三磷酸腺苷催化GTP的产生。一种可能的G蛋白 可由NME1通过GTP产生激活的包括由RAN基因编码的RAN GTP酶， 在几种PDX模型肺转移细胞中也有高表达。我假设一只乳房 肿瘤细胞将使用在肺微转移细胞中发现的显著的转录和代谢程序， 包括OxPhos，以促进转移。此外，我假设OxPhos产生能量来为GTP提供燃料 NME1产生激活RAN和其他G蛋白促进原发肿瘤转移进展 细胞。我的初步工作表明NME1和RAN的异位表达促进了原发肿瘤的肺转移 乳腺癌PDX小鼠体内的肿瘤细胞。这项工作将定义OxPhos的作用，转录和代谢 补给它的途径和潜在的OxPhos在推动乳腺癌中不依赖于ATP生成的功能 使用稳定同位素示踪、代谢组学和RNA测序的转移。此外，我还将定义 NME1和RAN在乳腺癌转移中的作用及其协同或协同作用 PDX型号。该项目的发现将揭示分子和代谢途径优先用于 转移细胞提供对转移病因的洞察，提供新的标记以改进检测和 寻找治疗机会，以改善乳腺癌转移的治疗。

PROJECT SUMMARY/ABSTRACT Mitochondria perform many crucial functions including energy production through oxidative phosphorylation (OxPhos) and their dysfunction has been implicated in pathologies including cancer. Evidence suggests metastasis is seeded by rare subpopulations of primary tumor cells with unique biological properties. Defining these unique properties is crucial for developing effective therapies. Using single-cell RNA sequencing (scRNAseq) on patient-derived xenograft (PDX) models of triple negative breast cancer, we generated the first single cell atlas of PDX micrometastatic breast cancer cells in lungs and their corresponding primary tumor cells. We found lung micrometastatic cells, and a small subpopulation of primary tumor cells, had elevated mitochondrial membrane potential and upregulated previously uncharacterized genes in context of breast cancer metastasis, including NME1 and RAN as well as genes associated with OxPhos. We also found breast cancer cells functionally require OxPhos for seeding in the lung. Increased OxPhos provides more ATP available for metastatic cells to use in energy consuming processes, including the production of GTP from ATP for activating G proteins and downstream pathways implicated with invasiveness in cancers. The NME1 gene encodes for NME1 nucleoside diphosphate kinase that catalyzes the production of GTP using ATP. One possible G protein that could be activated by NME1 through GTP production includes the Ran GTPase, encoded by the RAN gene, which was also highly expressed in lung metastatic cells in several PDX models. I hypothesize primary breast tumor cells will use prominent transcriptional and metabolic programs found in lung micrometastatic cells, including OxPhos, to promote metastasis. Furthermore, I hypothesize that OxPhos generates energy to fuel GTP production by NME1 to activate Ran and other G-proteins to facilitate metastatic progression of primary tumor cells. My preliminary work shows ectopic expression of NME1 and RAN promotes lung metastasis of primary tumor cells in breast cancer PDX mice. This work will define the role of OxPhos, transcriptional and metabolic pathways feeding into it, and potential OxPhos functions independent of ATP-generation in driving breast cancer metastasis using stable isotope tracing, metabolomics, and RNA sequencing. Additionally, I will define the role of NME1 and RAN and how they may work together or in parallel to promote breast cancer metastasis in PDX models. Findings of this project will reveal molecular and metabolic pathways preferentially used in metastatic cells to provide insight to metastasis etiology, present novel markers for improved detection and discover therapeutic opportunities to pursue to improve treatment for breast cancer metastasis.