Defining the formation and function of carcinoma-associated mesenchymal stem cells in the ovarian cancer microenvironment

摘要： 卵巢癌是美国最致命的妇科恶性肿瘤，5年死亡率超过50%。 卵巢癌的特点是早期腹膜内转移和复杂的发展， 微环境支持肿瘤细胞生长、存活和扩散。理解并最终 以这种促癌肿瘤微环境为靶点， 接近。我的最终目标是成为一名世界级的独立医生科学家， 癌症微环境，以开发新的治疗方法，改善卵巢癌妇女的预后。 癌这份提案描述了重要的创新研究，这将为我的未来奠定基础 除了提供对我的成功至关重要的必要技能和指导之外，我还提供了职业生涯。 卵巢肿瘤微环境（TME）是一个由细胞和化学成分组成的多样化系统。的 细胞TME包括肿瘤细胞和非恶性基质细胞。化学TME以酸中毒为标志， 缺氧癌相关间充质干细胞（CA-MSC）是肿瘤内的多能基质细胞， - 细胞TME，其可以分化成多种促肿瘤发生基质细胞类型，包括成纤维细胞， 肌成纤维细胞和脂肪细胞。CA-MSC基因型正常，无恶性潜能，但 在功能上不同于正常组织或骨髓来源的MSC。与正常MSCs相比，CA-MSCs 显示具有非常高的骨形态发生蛋白（BMP）表达的独特分子表型。 由于这种独特的表型，这些CA-MSCs强烈促进卵巢癌生长，增强化疗效果， 抵抗并丰富癌症干细胞样群体。 CA-MSC如何发展其独特的表型仍不清楚。我的初步数据显示 分泌因子诱导一些与CA-MSC相关的分子变化。另一个潜在的调解人 CA-MSC表型的主要特征是缺氧。缺氧是已知影响正常MSC的化学TME的标志 功能在癌症中，缺氧影响肿瘤：基质相互作用和缺氧是BMP的关键调节因子 高水平表达是卵巢癌CA-MSC的特征。初步数据显示缺氧 增强肿瘤细胞在正常MSC中诱导CA-MSC表达谱的能力。而 这种诱导的机制是未知的，因为CA-MSC在遗传上是正常的，但仍保持其独特的 表型跨越多个传代，肿瘤诱导的表观遗传调控可能是关键的形成， CA-MSC表型。事实上，初步数据表明CA-MSC表现出显著的低甲基化， 正常的MSC。 除了影响CA-MSC的形成外，缺氧还可能严重调节CA-MSC的功能。 间充质干细胞已经在卵巢TME中建立。我的初步数据显示缺氧可以维持 CA-MSC的“干性”减缓生长并维持分化能力。此外，我的数据表明， 缺氧诱导因子途径，主要的缺氧信号传导途径，在CA-MSC中是过度活跃的， 正常的MSC。因此，缺氧可能是卵巢TME内CA-MSC的关键调节剂。 我的主要研究目标是了解CA-MSCs如何获得其独特的表型，并随后相互作用 影响卵巢癌微环境的功能。为了实现这一目标，我建议两个 具体目标： 1)确定正常MSC获得CA-MSC样表型的能力 2)确定缺氧对肿瘤微环境中已建立的CA-MSC的影响。 除了进一步了解CA-MSCs在卵巢癌中的作用外， 将培养必要的专业知识，为研究卵巢TME的独立职业生涯。在培训结束时 在此期间，我将开发出一套新颖的技能，它融合了多位科学领导者的专业知识， 经过独特训练的医生科学家是研究卵巢癌微环境的理想选择。

ABSTRACT: Ovarian cancer is the most deadly US gynecologic malignancy with a mortality rate that exceeds 50% at 5 years. Ovarian cancer is characterized by early intraperitoneal metastasis and the development of a complex microenvironment which supports tumor cell growth, survival and spread. Understanding and eventually targeting this cancer-promoting tumor microenvironment offers the potential for powerful new therapeutic approaches. My ultimate goal is to become a world-class independent physician scientist studying the ovarian cancer microenvironment in order to develop new treatments and improve outcomes for women with ovarian cancer. This proposal describes important and innovative research which will lay the foundation for my future career in addition to providing the necessary skills and mentorship vital for my success. The ovarian tumor microenvironment (TME) is a diverse system of cellular and chemical components. The cellular TME includes tumor cells and non-malignant stromal cells. The chemical TME is marked by acidosis and hypoxia. Carcinoma-associated mesenchymal stem cells (CA-MSCs) are multi-potent stromal cells within the cellular TME that can differentiate into multiple pro-tumorigenic stromal cell types including fibroblasts, myofibroblasts, and adipocytes. CA-MSCs are genotypically normal without malignant potential but are functionally different than normal tissue or bone marrow derived MSCs. Compared to normal MSCs, CA-MSCs demonstrate a unique molecular phenotype with very high expression of bone morphogenetic proteins (BMPs). Due to this unique phenotype, these CA-MSCs strongly promote ovarian cancer growth, enhance chemotherapy resistance and enrich the cancer stem cell-like population. How CA-MSCs develop their unique phenotype remains unclear. My preliminary data indicate that tumor secreted factors induce some of the molecular changes associated with CA-MSCs. Another potential mediator of the CA-MSC phenotype is hypoxia. Hypoxia is a hallmark of the chemical TME known to impact normal MSC function. In cancer, hypoxia influences tumor:stromal interactions and hypoxia is a key regulator of BMP expression—high levels of which characterize ovarian cancer CA-MSCs. Preliminary data indicates that hypoxia enhances the ability of tumor cells to induce a CA-MSC expression profile in normal MSCs. While the mechanism of this induction is unknown, given CA-MSCs are genetically normal yet maintain their unique phenotype across multiple passages, tumor-induced epigenetic regulation may be critical to the formation of the CA-MSC phenotype. Indeed, preliminary data indicates CA-MSCs exhibit significant hypomethylation compared to normal MSCs. In addition to influencing the formation of a CA-MSC, hypoxia may also critically regulate the function of CA- MSCs already established in the ovarian TME. My preliminary data suggests that hypoxia maintains the “stemness” of CA-MSCs slowing growth and maintaining differentiation capacity. Further, my data suggests that the hypoxia inducible factor pathway, the main hypoxia signaling pathway, is hyper-active in CA-MSCs compared to normal MSCs. Thus hypoxia may be a critical modulator of CA-MSCs within the ovarian TME. My main research goal is to understand how CA-MSCs obtain their unique phenotype and subsequently interact with and influence the function of the ovarian cancer microenvironment. To achieve this goal, I propose two specific aims: 1) Determine the ability of normal MSCs to acquire a CA-MSC-like phenotype 2) Determine the impact of hypoxia on established CA-MSCs within the tumor microenvironment. In addition to furthering our understanding of CA-MSCs in ovarian cancer, the proposed research and training will cultivate expertise necessary for an independent career studying the ovarian TME. By the end of the training period, I will have developed a novel skill set which merges the expertise of multiple scientific leaders yielding a uniquely trained physician scientist ideal for the study of the ovarian cancer microenvironment.