Obscurin-Deficient Breast Epithelia Generate Secreted Factors that Prime Lung Vascular Smooth Muscle Cell Pre-metastatic Microenvironment Formation

项目概要/摘要： 迫切需要阻断转移性扩散的新疗法来提高乳腺癌患者的生存率。 转移前的小生境发展已被确定为成功转移的关键里程碑， 以响应肿瘤分泌因子的释放。转移前小生境的关键是转移前 转移微环境（PMM）由细胞外基质（ECM）蛋白组成，由居民沉积 基质细胞，增强转移。到目前为止，PMM的发展一直是在研究的背景下， 使用富含肿瘤抑制基因和癌基因突变的细胞系的高转移性肿瘤模型，然而没有 转移性驱动基因和PMM形成之间的直接机制联系尚未被破译。 Obscurins最近被认为是乳腺癌中有效的转移抑制剂。生化证据 我们的研究小组在乳腺上皮细胞中将obscurin缺失与PI 3 K/Akt 2激活机制联系起来， 肿瘤发生和转移扩散。然而，目前还没有研究表明， obscurin在乳腺上皮和PMM发育中的作用。这项研究将检验一个新的假设， 在乳腺上皮中引发血管平滑肌细胞（vSMC）衍生纤维连接蛋白和胶原1a 1沉积 在PMM通过分泌因子，增强转移。 我申请的目的是研究obscurin缺陷的乳腺上皮细胞分泌 细胞因子（OBEF）驱动vSMC ECM纤连蛋白和胶原1a 1沉积。OBEF将被隔离， OBSCN敲除（KO）MCF 10A细胞克隆，而人肺动脉平滑肌细胞（HPASMC） 细胞系将是代表性的PMM细胞群，原因如下：1）肺PMM发育是 依赖于表型活化的肺vSMC衍生的ECM产生，和2）转移前肺，vSMC- 衍生的ECM已显示增强转移前肺实质中的转移性肺接种。在 特别是，我将研究OBEF驱动的vSMC衍生的ECM纤连蛋白和胶原1a 1的潜在变化 以及它们与增强的肺转移种植（Aim 1）的联系。然后我会找出幕后黑手 驱动随后的vSMC ECM纤连蛋白和胶原蛋白1a 1在肺PMM中产生的因子（目的2）。 总之，这些研究将把我们对PMM发展的认识与原发性黑色素瘤的主要抑制因子联系起来。 肿瘤转移，表明与PMM的基质成分相关的第一个可靶向肿瘤生物标志物 一代

Project Summary/Abstract: New therapies blocking metastatic spread are greatly needed to improve breast cancer patient survival. Pre-metastatic niche development has been identified as a key milestone to successful metastasis, generated in response to a growing tumor’s release of secreted factors. Critical to the pre-metastatic niche is the pre- metastatic microenvironment (PMM) composed of extracellular matrix (ECM) proteins, deposited by resident stromal cells, that enhance metastasis. To date, PMM development has been studied solely in the context of highly metastatic tumor models using cell lines rich in tumor suppressor and oncogene mutations, however no direct mechanistic connections between metastatic driver genes and PMM formation have yet been deciphered. Obscurins have recently been pinned as potent metastasis suppressors in breast cancer. Biochemical evidence from our group has mechanistically linked obscurin loss to PI3K/Akt2 activation in breast epithelial cells, driving oncogenesis and metastatic spread. However, no study has yet drawn the connection between the loss of obscurin in breast epithelia and PMM development. This study will test the novel hypothesis that loss of obscurin in breast epithelia primes vascular smooth muscle cell (vSMC)-derived fibronectin and collagen 1a1 deposition in the PMM through secreted factors, potentiating metastasis. The goal of my application is to investigate the potential of obscurin-deficient breast epithelia secreted factors (OBEFs) to drive vSMC ECM fibronectin and collagen 1a1 deposition. OBEFs will be isolated from OBSCN knock-out (KO) MCF10A cell clones, while the human pulmonary artery smooth muscle cell (HPASMC) line will be the representative PMM cell population for the following reasons: 1) Lung PMM development is dependent on phenotypically activated lung vSMC-derived ECM production, and 2) Pre-metastatic lung, vSMC- derived ECM has been shown to enhance metastatic lung seeding in the pre-metastatic lung parenchyma. In particular, I will investigate potential changes in OBEF-driven vSMC-derived ECM fibronectin and collagen 1a1 and their connection to enhanced lung metastatic seeding (Aim 1). Then, I will identify the responsible secreted factors (Aim 2) that drive the subsequent vSMC ECM fibronectin and collagen 1a1 production in the lung PMM. Together, these studies will connect our knowledge of PMM development back to a major suppressor of primary tumor metastasis, indicating the first targetable tumor biomarker linked to the stromal component of PMM generation.