Influence of hemodynamic shear stress on circulating tumor cells

循环肿瘤细胞（CTC）暴露于被认为会降低其存活的各种损伤，包括缺乏免疫抑制剂。 锚定和营养支持从原发性肿瘤微环境，免疫介导的破坏， 暴露于可能机械破坏它们的血液动力学力。然而，相对贡献 这些因素对CTC存活的影响及其在转移中的总体作用尚不清楚。最近的研究表明， 来自许多组织来源的癌细胞积极抵抗流体剪切应力（FSS）的破坏，这意味着存活的 CTC并不像怀疑的那样机械脆弱。我们的长期目标是了解 对CTC的影响以及这如何有助于转移。本提案的目的是确定 癌细胞中的FSS抗性机制及其在转移定植中的作用。我们的核心假设是 有活力的CTC对FSS的机械适应促进了它们在循环中的存活， 转移的后续事件。我们的假设是基于我们以前发表的和初步的数据 下面列出的数据以及最近发表的其他数据支持我们的假设。的 这项研究的基本原理是，一旦我们了解了FSS抗性的机制， 将代表一种新的治疗方法，旨在通过提高CTC的存活率来降低CTC的存活率。 由于循环中自然存在的机械力而造成的破坏。根据初步数据， 本研究将通过以下几个方面来验证中心假设：1）明确FSS的分子机制 耐药性; 2）确定FSS暴露对转移性定植的影响; 3）确定 作为一种抗转移策略。为了实现这些目标，我们将采用 遗传筛选，以确定介导FSS抗性的新基因，并确定它们与RhoA- 肌动球蛋白相互作用CTC的短期存活将使用新的小鼠模型来评估，以测量 肺中完整CTC的截留和通过血浆生物标志物测量的CTC的破坏。我们将验证 在类似的试验中在正向遗传筛选中鉴定的新基因。我们会确定罗阿的参与- FSS激活雅普，支持微循环中癌细胞的存活和外渗。 最后，我们将测试临床上可操作的药物的潜力，使细胞对FSS敏感，以及条件性 RhoA/雅普敲低以阻断小鼠模型中的生产性转移定植。拟议的研究是 创新，因为它代表了一种范式转变，从CTC机械脆弱的想法，通过阐明 活性CTC主动抵抗血流动力学破坏并驱动进一步事件的机制 在转移中。该研究具有重要意义，因为明确了FSS的机制和后果 CTC的耐药性将为癌症患者开辟全新的诊断和治疗可能性。

Circulating tumor cells (CTCs) are exposed to various insults thought to reduce their survival including lack of anchorage and trophic support from the primary tumor microenvironment, immune-mediated destruction and exposure to hemodynamic forces that may mechanically destroy them. However, the relative contribution of these factors to CTC survival and their overall role in metastasis is unclear. It has recently been shown that cancer cells from many tissue origins actively resist destruction by fluid shear stress (FSS), implying that viable CTCs are not mechanically fragile as suspected. Our long-term goal is to understand the biomechanical influences on CTCs and how this contributes to metastasis. The objective of this proposal is to determine the mechanism of FSS resistance in cancer cells and its role in metastatic colonization. Our central hypothesis is that mechano-adaptation of viable CTCs to FSS promotes their survival in the circulation and “primes” them for subsequent events in metastasis. Our hypothesis is based on our previously published and preliminary data presented below as well as recently published data from others which is supportive of our hypothesis. The rationale for the proposed research is that once we understand the mechanism underlying FSS resistance; this would represent a novel therapeutic approach aimed at decreasing the survival of CTCs by enhancing their destruction due to the mechanical forces that naturally exist in the circulation. Guided by preliminary data, the central hypothesis will be tested by pursuing the following specific aims: 1) Define molecular mechanisms of FSS resistance; 2) Determine the effect of FSS exposure on metastatic colonization; 3) Determine the effectiveness of inhibiting FSS resistance as an anti-metastatic strategy. To accomplish these aims, we will employ a forward genetic screen to identify novel genes that mediate FSS resistance and determine their involvement with RhoA- actomyosin interactions. Short-term survival of CTCs will be assessed using a novel mouse model to measure entrapment of intact CTCs in the lung and destruction of CTCs measured by a plasma biomarker. We will validate novel genes identified in a forward genetic screen in similar assays. We will determine the involvement of RhoA- YAP activation by FSS in supporting the survival and extravasation of cancer cells lodged in the microcirculation. Finally, we will test the potential of clinically actionable drugs that sensitize cells to FSS as well as conditional RhoA/YAP knockdown to block productive metastatic colonization in mouse models. The proposed research is innovative because, it represents a paradigm shift from the idea that CTCs are mechanically fragile by elucidating a mechanism whereby viable CTCs actively resist destruction by hemodynamic forces and drives further events in metastasis. The proposed research is significant because defining the mechanisms and consequences of FSS resistance in CTCs will open entirely new diagnostic and therapeutic possibilities in cancer patients.