Hematopoietic Stem Cell-Derived Carcinoma Associated Fibroblasts in Tumor

描述（由申请人提供）：肿瘤基质微环境作为治疗靶点具有令人兴奋的潜力。 实体瘤基质的主要成分是癌相关成纤维细胞（CAF），它产生结构基质、刺激生长、支持新血管形成并促进肿瘤转移。 研究表明 CAF 有多种来源，包括组织成纤维细胞、上皮间质转分化 (EMT) 和骨髓（即间充质干细胞）。我们开发了一种新型移植模型，其中经致死辐射的受体小鼠的骨髓由源自单个 EGFP 造血干细胞 (HSC) 的克隆细胞群重建。 我们使用该模型的研究表明，CAF 和循环成纤维细胞前体 (CFP) 源自 HSC，可促进肿瘤生长。 这种成纤维细胞前体和 CAF 的新型 HSC 来源是拟议研究的基础。 我们的假设是，HSC 衍生的 CFP 和 CAF 在肿瘤增殖、侵袭、迁移和转移中发挥着关键作用。然而，这些 HSC 衍生的 CAF 和 CFP 在肿瘤进展中的具体作用尚未得到研究。 也没有对 HSC 衍生的 CAF 与非 HSC 衍生的“常驻”人群进行直接比较。 拟议的研究将通过以下具体目标，利用我们的克隆细胞移植模型与Lewis肺癌（LLC）肿瘤模型结合来描述这种独特的细胞群，并确定它们对肿瘤进展的影响：1）确定HSC衍生的CFP和CAF促进肿瘤进展的机制。 该目标的第一个目标是通过流式细胞术、免疫组织化学和分子分析来比较 HSC 衍生的 EGFP CAF 和 EGFP“驻留”CAF。 然后，将在体外检查 HSC 衍生的 CFP 对肿瘤增殖、迁移和侵袭的影响，并在功能获得和/或功能丧失研究中鉴定和验证负责的肿瘤促进因素。 2) 确定肿瘤微环境中调节 HSC 来源的 CFP 募集、归巢、分化和成熟的因素。 研究将通过功能性体外实验来检查调节 HSC 衍生的 CFP 对肿瘤的影响的因素。 3) 确定HSC衍生的CFP和CAF对体内肿瘤的贡献。 这些研究将检验 HSC 衍生的 CFP 增强 LLC 致瘤性、进展和转移的能力。 目标 1 和 2 中确定的蛋白质/基因的功能重要性也将使用遗传缺陷模型或 siRNA 方法进行评估。 这些研究不仅有助于更好地了解基础肿瘤生物学，而且有可能识别出独特的癌症相关分子特征和 HSC 衍生的 CFP/CAF 特异性因子，这些因子可用于抑制实体瘤的生长和进展。

DESCRIPTION (provided by applicant): The tumor stromal microenvironment holds exciting potential as a therapeutic target. The major component of solid tumor stroma is the carcinoma associated fibroblast (CAF), which generates structural matrix, stimulates growth, supports neovascularization and promotes metastasis of tumor. Studies suggest various sources for CAFs including tissue fibroblasts, epithelial-to-mesenchymal transdifferentiation (EMT) and bone marrow (i.e., mesenchymal stem cells). We have developed a novel transplantation model in which the bone marrow of lethally irradiated recipient mice is reconstituted by a clonal population of cells derived from a single EGFP+ hematopoietic stem cell (HSC). Our studies using this model demonstrate that CAFs and circulating fibroblast precursors (CFPs) are of HSC origin and promote tumor growth. This novel HSC source for both fibroblast precursors and CAFs is the basis for the proposed studies. It is our hypothesis that HSC-derived CFPs and CAFs play a critical role in tumor proliferation, invasion, migration and metastasis; however the specific role of these HSC-derived CAFs and CFPs in tumor progression has not yet been investigated. Nor has direct comparison of HSC-derived CAFs to non-HSC-derived "resident" populations been conducted. The proposed studies will profile this unique population of cells and determine their influence on tumor progression using our clonal cell transplantation model in conjunction with Lewis lung carcinoma (LLC) tumor models through the following Specific Aims: 1) To determine the mechanisms by which HSC-derived CFPs and CAFs promote tumor progression. The first goal of this Aim is to compare HSC-derived EGFP+ CAFs and EGFP- "resident" CAFs via flow cytometric, immunohistochemical and molecular profiling. The effects of HSC-derived CFPs on tumor proliferation, migration and invasion will then be examined in vitro and the tumor-promoting factors responsible identified and validated in gain of function and/or loss of function studies. 2) To identify factors which regulate HSC-derived CFP recruitment, homing, differentiation and maturation in the tumor microenvironment. Studies will examine factors regulating the contribution of HSC-derived CFPs to tumor via functional in vitro experiments. 3) To determine the contributions of HSC-derived CFPs and CAFs to tumor in vivo. These studies will examine the ability of HSC-derived CFPs to enhance LLC tumorigenicity, progression and metastasis. The functional importance of proteins/genes identified in Aims 1 and 2 will also be evaluated using models of genetic deficiency or siRNA methods. Together these studies will not only lead to a better understanding of basic tumor biology, but have the potential to lead to the identification of unique cancer associated molecular signatures and HSC-derived CFP/CAF-specific factors that may be targeted to inhibit solid tumor growth and progression.