Evaluating How Fluid Shear Stress Alters Estrogen Receptor Phenotype in Metastatic Breast Cancer

项目总结 大约70%的乳腺癌患者会出现雌激素受体阳性(ER+)亚型。的 这些患者，大多数在治疗原发肿瘤时最初会对内分泌治疗有反应。不幸的是， 随着转移的扩散，这些患者中的许多人对内分泌治疗产生抵抗力，导致 患者死亡率显著增加，因为转移性乳腺癌没有可行的治疗方法。 转移后，目前的中位生存期为~5-10年，这加强了更好地 了解导致转移性肿瘤内分泌治疗抵抗的细胞机制。内分泌 转移部位的耐药性被认为是通过多种机制发生的，包括：(I) 雌激素受体，(Ii)额外突变的获得，和/或(Iii)雌激素和生长因子的改变 中介信号级联。在转移过程中，ER+乳腺癌细胞暴露于高剂量的 流体剪应力(FSS)(高达60dyn/cm2)和通过血管系统时流体引起的变形。 先前的工作已经发现，FSS诱导了包括那些相关的激酶通路的增加的激活 在癌细胞系的快速雌激素信号和相关的内分泌耐药方面。不幸的是，这个角色 FSS对ER+乳腺癌转移过程中ER信号调控和生物适应的影响 没有完全理解。为了阐明FSS如何驱动转移性乳腺癌的内分泌反应，我们建议 以下假设：ER+乳腺癌细胞暴露于FSS抑制ER表达并诱导 生长因子信号通路的激活和随后的内分泌抵抗。我们建议对此进行测试 假设使用模块化微流控平台，能够将乳腺癌细胞暴露于良好控制的环境中， 均匀大小和持续时间的FSS，模拟在转移扩散过程中发生的原位条件。 具体地说，我们将(1)确定FSS如何改变雌激素受体的表达和生长因子途径，从而 与雌激素信号通路相互作用，以及(2)评估FSS对获得性抵抗力的影响 内分泌治疗。提出的技术的一个特点是能够执行大量的芯片外审问 并使用荧光显微镜进行细胞选择和芯片上的单细胞分析来表征 单个癌细胞的异质性和反应。这些研究将提供新的基础 深入了解FSS对雌激素信号的影响以确定ER+内分泌抵抗的新机制 转移部位的乳腺癌，这有可能导致设计用于治疗转移的新疗法 呃+乳腺癌。

PROJECT SUMMARY Approximately 70% of breast cancer patients will present with an estrogen receptor positive (ER+) subtype. Of these patients, most will initially respond to endocrine therapy when treating the primary tumor. Unfortunately, following metastatic spread, many of these patients develop a resistance to endocrine therapies which results in a significant increase in patient mortality because there is no viable treatment for metastatic breast cancer. Following metastasis, the current median survival time is ~5-10 years, which reinforces the critical need to better understand the cellular mechanisms leading to endocrine therapy resistance in metastatic tumors. Endocrine resistance at metastatic sites is hypothesized to occur through multiple mechanisms including: (i) loss of the estrogen receptor, (ii) acquisition of additional mutations, and/or (iii) alterations in estrogen and growth factor mediated signaling cascades. During metastasis, ER+ breast cancer cells are exposed to high magnitudes of fluid shear stress (FSS) (up to 60 dyn/cm2) and fluid-induced deformation while traveling through the vasculature. Prior work has identified that FSS induces an increased activation of kinase pathways, including those involved in rapid estrogen signaling and associated endocrine resistance in cancer cell lines. Unfortunately, the role for FSS on the regulation of ER signaling and the biological adaptation of ER+ breast cancer during metastasis is not fully understood. To elucidate how FSS drives endocrine response in metastatic breast cancer, we propose the following hypothesis: Exposure of ER+ breast cancer cells to FSS represses ER expression and induces activation of growth factor signaling cascades and subsequent endocrine resistance. We propose to test this hypothesis utilizing a modular microfluidic platform capable of exposing breast cancer cells to well-controlled, uniform magnitudes and durations of FSS that mimics in situ conditions that occur during metastatic spread. Specifically, we will (1) Determine how FSS alters estrogen receptor expression and growth factor pathways that interact with estrogen signaling cascades, and (2) Evaluate the effects of FSS on the acquired resistance to endocrine therapy. A hallmark of the proposed technology is the ability to perform both bulk off-chip interrogation and cellular selection and on-chip single cell analysis using fluorescent microscopy to characterize the heterogeneous nature and response of individual cancer cells. These studies will provide new fundamental insight into the effects of FSS on estrogen signaling to identify novel mechanisms of endocrine resistance in ER+ breast cancer at metastatic sites, this has the potential to lead to novel therapies designed to treat metastatic ER+ breast cancer.