Defining the Roles of Mitochondria in Breast Cancer Metastasis

项目概要/摘要 线粒体执行许多关键功能，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。证据表明 转移由具有独特生物学特性的原发肿瘤细胞的罕见亚群接种。限定 这些独特的性质对于开发有效的疗法至关重要。使用单细胞RNA测序 在三阴性乳腺癌的患者来源的异种移植物（PDX）模型上，我们产生了 肺中PDX微转移性乳腺癌细胞及其相应原发性肿瘤的第一个单细胞图谱 细胞我们发现肺微转移细胞和原发性肿瘤细胞的一个小亚群， 乳腺癌中线粒体膜电位和上调的先前未表征的基因 转移，包括NME 1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用于在肺中接种。增加OxPhos提供更多的ATP， 转移细胞用于能量消耗过程，包括从ATP产生GTP用于激活 G蛋白和下游通路与癌症的侵袭性有关。NME 1基因编码 NME 1核苷二磷酸激酶，催化使用ATP产生GTP。一种可能的G蛋白 可被NME 1通过GTP产生激活的包括Ran GTP酶，由RAN基因编码， 其在几种PDX模型的肺转移细胞中也高度表达。我假设原发性乳腺癌 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产生能量来驱动GTP 通过NME 1的产生来激活Ran和其他G蛋白以促进原发性肿瘤的转移进展 细胞我的初步研究表明，NME 1和RAN的异位表达促进了原发性肺癌的肺转移。 乳腺癌PDX小鼠中的肿瘤细胞。这项工作将定义OxPhos的作用，转录和代谢 途径喂养它，和潜在的OxPhos功能独立于ATP的产生，在驱动乳腺癌 使用稳定同位素示踪、代谢组学和RNA测序来检测转移。此外，我将定义 NME 1和RAN的作用以及它们如何共同或平行促进乳腺癌转移， PDX模型。该项目的发现将揭示优先用于以下疾病的分子和代谢途径： 转移性细胞提供转移病因学的洞察，提出用于改进检测的新标志物， 发现治疗机会，寻求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.