Bone marrow niche regulation of disseminated tumor cell dormancy, reactivation, and metastasis.

项目总结/摘要 ER+乳腺癌患者在最初诊断后数十年可能发生转移性复发。大多数乳腺 癌症相关的死亡是由转移引起的， 防止重新激活是一个关键的挑战。这些努力由于缺乏了解而受到阻碍， 骨髓中的癌细胞休眠，被认为是转移复发的细胞来源。得不好 了解肿瘤细胞如何与骨髓微环境相互作用，以及这些相互作用如何调节 肿瘤细胞休眠和逃逸。我提议的研究旨在开发一种休眠的小鼠模型， 研究指导K99期患者样本中骨髓小生境的空间组织， 建立了一个生物材料的休眠模型在独立的R 00阶段。我假设（i）癌症干细胞是 负责转移性复发的播散性肿瘤细胞亚群和（ii）骨髓小生境，包括 健康的干细胞龛促进这些细胞的休眠和再活化。在目标1中，我将开发一部小说 骨髓中激素反应性乳腺癌休眠的小鼠模型并评估其存在， 表型和微环境调控的播散性肿瘤细胞使用光学组织清除/3D 全骨成像。在目标2中，我将研究肿瘤细胞与骨髓相互作用的假设， 通过来自患者的骨髓活检的高维空间分析的小生境控制肿瘤细胞表型 包括成像质谱细胞术（IMC）和空间单细胞RNA测序（scRNAseq）。 在目标3中，我将通过创建机械模拟物来开发休眠骨髓龛的生物材料模型 骨髓的三个不同的隔室，并评估机械感应在诱导和 保持休眠状态。在K99阶段，Max Wicha教授将担任我的主要导师。博士 Wicha是癌症干细胞领域的先驱，也是乳腺癌生物学和转移方面的专家。我会 与我的合作者和指导团队合作并咨询，包括Fei Wen教授（成像质谱细胞术）， Evan Keller（单细胞空间分析程序）、Dafydd托马斯博士（病理学核心）、加里卢克教授 Monika Burness教授（乳腺癌临床肿瘤学）和索菲亚Merjaver教授（乳腺癌 分子生物学）。我的K99训练将包括开发一种新的骨髓休眠小鼠模型， 学习生物信息学方法，分析IMC中细胞表型的空间贡献， scRNAseq数据推动我开发一种合成的休眠骨髓小生境模拟物， 生物材料在独立R 00阶段。总而言之，拟议的研究将解决一个紧迫的、未得到满足的问题， 需要确定骨髓小生境在乳腺癌休眠和再激活中的作用，这可能提供 这是一条识别转移风险较高的患者并开发针对再激活的治疗方法的前进道路。

PROJECT SUMMARY / ABSTRACT Metastatic relapse may occur in patients with ER+ breast cancer decades after original diagnosis. Most breast cancer related deaths are caused by metastasis and thus identifying at-risk patients and developing therapies to prevent reactivation are a crucial challenge. These efforts have been impeded by a lack of understanding of cancer cell dormancy in the bone marrow, believed to be the cellular source of metastatic relapse. It is not well understood how tumor cells interact with the bone marrow microenvironment and how these interactions regulate tumor cell dormancy and escape. My proposed research seeks to develop a mouse model of dormancy and investigate the spatial organization of the bone marrow niche in patient samples in the mentored K99 phase and develop a biomaterial model of dormancy in the independent R00 phase. I hypothesize (i) cancer stem cells are a subset of disseminated tumor cells responsible for metastatic relapse and (ii) the bone marrow niche, including the healthy stem cell niche, facilitates dormancy and reactivation of these cells. In Aim 1, I will develop a novel mouse model of hormone responsive breast cancer dormancy in bone marrow and evaluate the presence, phenotype, and microenvironmental regulation of disseminated tumor cells using optical tissue clearing/3D imaging of whole bone. In Aim 2, I will investigate the hypothesis that tumor cell interactions with the bone marrow niche control tumor cell phenotype via high dimensional spatial analysis of bone marrow biopsies from patients with breast cancer including imaging mass cytometry (IMC) and spatial single cell RNA sequencing (scRNAseq). In Aim 3, I will develop a biomaterial model of the dormant bone marrow niche via creating mechanical mimics of the three distinct compartments of bone marrow and evaluate the role of mechanosensing in induction and maintenance of dormancy. In the K99 phase of the award, Prof Max Wicha will serve as my main mentor. Dr. Wicha is a pioneer in the cancer stem cell field and is an expert in breast cancer biology and metastasis. I will work with and consult my collaborators and mentoring team, including Prof Fei Wen (imaging mass cytometry), Evan Keller (single cell spatial analysis program), Dr. Dafydd Thomas (pathology core), Prof Gary Luker (microscopy), Prof Monika Burness (breast cancer clinical oncology) and Prof Sofia Merjaver (breast cancer molecular biology). My K99 training will consist of developing a novel mouse model of bone marrow dormancy and learning bioinformatics approaches to analyze spatial contributions to cellular phenotype in IMC and scRNAseq data to propel me toward developing a synthetic dormant bone marrow niche mimic using biomaterials during the independent R00 phase. In sum, the proposed research will address an urgent, unmet need to identify the role of the bone marrow niche in breast cancer dormancy and reactivation, which may provide a path forward for identifying patients at higher risk of metastasis and developing therapies against reactivation.