(PQC2) Localization as a determinant of cancer dormancy

 描述(申请人提供)：这项提案旨在回答PQC-2这个具有挑衅性的问题：在治疗后，什么分子或细胞事件会导致肿瘤休眠，什么会导致复发？我们将通过检查骨髓(BM)来解决这个问题，众所周知，该位置不仅为血液系统恶性肿瘤提供了有利的微环境，而且为经常在该位置种植和存活的实体瘤细胞提供了有利的微环境。这些细胞可以在长时间的明显不活跃后重新出现，并成为新的癌症生长的来源。了解休眠是如何调节的，对于制定旨在防止癌症复发的治疗策略非常重要。我们的中心假设是，本地化是休眠的一个重要决定因素。将正常的造血干细胞(HSCs)定位到骨髓中合适的位置对于维持HSC的静止和长期功能至关重要。在这里，我们建议研究休眠与化疗后恶性细胞在骨髓中定位的关系。我们假设，休眠是通过在静止的壁龛中定位恶性细胞来维持的，随后改变其定位的事件可以触发恶性细胞退出其静止状态。通过跟踪 在小鼠骨髓中表达一种新的细胞周期荧光指示剂的单个癌细胞使用活体显微镜，我们将确定细胞保持静止的壁龛位置 处于G0状态。我们将通过使用双光子磷光寿命显微镜(2PLM)以高空间分辨率绘制BM中的局部氧浓度来研究静止和缺氧之间的联系，并通过激光显微切割和捕获利基细胞进行RNA-SEQ鉴定利基特异的分子表达。最后，我们将检查利基成分的遗传或药物操作是否会导致细胞定位的改变、细胞周期状态的改变以及对化疗的敏感性。如果成功，这项工作可能会导致一种新的方法，通过靶向肿瘤细胞的定位来使其对化疗敏感。

 DESCRIPTION (provided by applicant): This proposal aims to address the provocative question PQC- 2: What molecular or cellular events establish tumor dormancy after treatment and what leads to recurrence? We will address this question by examining the bone marrow (BM), a location known to provide a favorable microenvironment not only for hematologic malignancies, but also for solid tumor cells that frequently seed and persist in this location. These cells can reemerge after prolonged periods of apparent inactivity and become the source of new cancer growth. Understanding how dormancy is regulated is important for developing therapeutic strategies that aim to prevent cancer relapse. Our central hypothesis is that localization is an important determinant of dormancy. Localization of normal hematopoietic stem cells (HSCs) to proper niches in the BM is critical for maintaining quiescence and long-term function of the HSC. Here we propose to investigate the relationship between dormancy and localization of malignant cells in the BM following chemotherapy. We hypothesize that dormancy is maintained by localization of malignant cells in quiescent niches, and subsequent events that alter their localization can trigger the malignant cells to exit their quiescent state. By tracking individual cancer cells expressing a novel cell cycle fluorescent indicator in the mouse BM using intravital microscopy, we will identify the location of quiescent niches where cells are maintained in the G0 state. We will examine the link between quiescence and hypoxia by mapping local oxygen concentration in the BM with high spatial resolution using two-photon phosphorescence lifetime microscopy (2PLM), and identify niche-specific molecular expression by laser microdissection and capturing of niche cells for RNA-seq. Finally, we will examine if genetic or pharmacologic manipulations of the niche components can result in altered cellular localization, changes in cell cycle status, and susceptibility to chemotherapy. If successful, this work can lead to a new way of sensitizing cancer cells to chemotherapy by targeting their localization.