Molecular Basis of Slits as Tumor Suppressors Controlling CXCR4/SDF1 in Breast

狭缝作为肿瘤抑制因子控制乳腺 CXCR4/SDF1 的分子基础

• 批准号: 8063686
• 负责人: LINDSAY E HINCK
• 金额: $ 3.33万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA CRUZ
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8063686
• 关键词: Address; Animal Model; Biological Assay; Biological Models; Blood Vessels; Breast; Breast Cancer Cell; CXCL12 gene; CXCR4 gene; Cancer Biology; Carcinoma; Cell Proliferation; Cells; Conflict (Psychology); Cues; Data; Development; Disease; Distant Metastasis; Down-Regulation; Ductal Epithelial Cell; Endothelial Cells; Environment; Epigenetic Process; Epithelial; Epithelial Cells; Epithelium; Fibroblasts; G-Protein-Coupled Receptors; Gene Expression; Gene Mutation; Generations; Genes; Genetic; Gland; Goals; Growth; Human; Hyperplasia; Immunoblotting; Immunohistochemistry; Knock-out; Lead; Lesion; Ligands; Link; Literature; Malignant - descriptor; Malignant Neoplasms; Mammary Neoplasms; Mammary gland; Matrix Metalloproteinases; Mediating; Molecular; Mutation; Neoplasm Metastasis; Organoids; Pathway interactions; Phenotype; Phosphorylation; Physiology; Plastics; Play; Primary Lesion; Primary Neoplasm; Process; Proteins; Research; Roche brand of trastuzumab; Role; Signal Transduction; Site; Source; Staging; Surveys; Tars; Tissues; Transplantation; Trastuzumab; Tumor Angiogenesis; Tumor Suppressor Proteins; Up-Regulation; Vascular Endothelial Growth Factors; angiogenesis; base; cell motility; chemokine; genetic profiling; in vivo; inhibitor/antagonist; loss of function; loss of function mutation; malignant breast neoplasm; mammary epithelium; neoplastic; neovascularization; null mutation; overexpression; public health relevance; receptor; response; therapeutic target; tumor; tumor growth; tumor progression; tumorigenesis; tumorigenic

DESCRIPTION (provided by applicant): The goal of cancer biology is to understand the progression of genetic and epigenetic changes occurring in cells as they become tumorigenic. Many studies have demonstrated a critical role for CXCR4 in guiding metastasizing breast cancer cells to sites with high levels of its ligand SDF1 (CXCL12). In contrast, relatively few studies have explored the consequences of having this pathway deregulated early in lesion development, even though a large fraction (>90%) of human breast tumors display inappropriate CXCR4 expression at very early stages of transformation. The observation that CXCR4 is upregulated early in the disease process, combined with recent studies demonstrating that carcinoma associated fibroblasts serve as a local source of its ligand SDF1, have fueled speculation that CXCR4 may also play a pivotal role in primary tumor growth. We have identified such a disease signature in hyperplastic lesions of mammary glands harboring loss-of-function in Slit2 and Slit3 or its Robo1 receptor, giving us the unique opportunity to understand the function of CXCR4 and SDF1 in the early stages of breast transformation within the integrated physiology of an animal model. Our preliminary data demonstrate that loss-of-function mutations in Slits or their Robo1 receptor lead to loss of tissue organization, elevated proliferation and a host of changes in the microenvironment, including increased angiogenesis. Based on our preliminary data, the overall hypothesis of the application is that loss of SLIT/ROBO1 signaling in breast leads to upregulated SDF1/CXCR4, which, in turn, contributes to epithelial transformation and generation of the tumor microenvironment. To address this hypothesis, the Specific Aims of this proposal are three-fold. In Aim I, we propose to investigate the role SDF1/CXCR4 signaling plays in early lesion development by determining the signaling status of CXCR4 in Slit2-/-;Slit3-/- and Robo1-/- tissue using both gain- and loss-of-function approaches. We will also evaluate whether similar expression changes occur between Slits, Robo1 and Cxcr4 in human breast tumors. In Aim II, we propose to define the cross talk that occurs between mammary epithelia and stroma by generating glands in which SLIT/ROBO1 signaling is selectively eliminated in the epithelia or stroma. In Aim III, we investigate the pro-angiogenic environment that arises in the absence of SLIT/ROBO1 signaling. We propose to elucidate the role of SDF1, alone, in promoting neoangiogenesis by eliminating VEGF activation in the Robo1-null background. We also propose to explore the role of Slit2 and Slit3 as tumor suppressors by re-expressing the genes in breast cancer cells and evaluating the effects on tumor growth and tumor angiogenesis. In summary, we have identified SDF1/CXCR4 as key, downstream regulatory targets of SLIT/ROBO1 signaling in vivo. We propose to elucidate how misregulation of this chemokine axis orchestrates inappropriate interactions between cells and their environment, leading to transformation of the tissue and surrounding microenvironment. PUBLIC HEALTH RELEVANCE: The genesis of breast cancer has remained elusive. Even though it is considered a heritable disease, it is estimated that only 5-10% of all human breast cancers are causally linked to known genetic mutations. Identifying genes whose mutations allow a lesion to progress and become malignant is crucial for identifying potential therapeutic targets. For a number of cancers, prominently breast, a candidate target with an established role in metastasis is the G-protein coupled receptor CXCR4. The goal of this application is to understand how CXCR4 contributes to tumor progression using breast as a model system.

描述（由申请人提供）：癌症生物学的目标是了解细胞在致瘤时发生的遗传和表观遗传变化的进展。 许多研究表明 CXCR4 在引导乳腺癌细胞转移至其配体 SDF1 (CXCL12) 水平高的部位方面发挥着关键作用。 相比之下，尽管大部分（>90%）人类乳腺肿瘤在转化的早期阶段表现出不适当的 CXCR4 表达，但相对较少的研究探讨了在病变发展早期解除该通路调控的后果。 CXCR4 在疾病过程早期上调的观察结果，加上最近的研究表明癌相关成纤维细胞是其配体 SDF1 的局部来源，这引发了人们的猜测：CXCR4 也可能在原发性肿瘤生长中发挥关键作用。 我们已经在乳腺增生性病变中发现了这种疾病特征，其中 Slit2 和 Slit3 或其 Robo1 受体功能丧失，这为我们提供了独特的机会来了解 CXCR4 和 SDF1 在动物模型的综合生理学中乳腺转化早期阶段的功能。 我们的初步数据表明，Slits 或其 Robo1 受体的功能丧失突变会导致组织组织丧失、增殖增加以及微环境的一系列变化，包括血管生成增加。 根据我们的初步数据，该应用的总体假设是乳腺中 SLIT/ROBO1 信号传导的缺失导致 SDF1/CXCR4 上调，进而促进上皮细胞转化和肿瘤微环境的生成。 为了解决这一假设，该提案的具体目标有三个。 在目标 I 中，我们建议通过使用功能获得和丧失功能的方法确定 Slit2-/-、Slit3-/- 和 Robo1-/- 组织中 CXCR4 的信号状态，研究 SDF1/CXCR4 信号在早期病变发展中的作用。 我们还将评估人类乳腺肿瘤中 Slits、Robo1 和 Cxcr4 之间是否发生类似的表达变化。 在目标 II 中，我们建议通过生成腺体来定义乳腺上皮和间质之间发生的串扰，其中 SLIT/ROBO1 信号在上皮或间质中被选择性消除。 在目标 III 中，我们研究了在没有 SLIT/ROBO1 信号传导的情况下出现的促血管生成环境。 我们建议通过消除 Robo1 缺失背景中的 VEGF 激活来阐明 SDF1 单独在促进新血管生成中的作用。 我们还建议通过在乳腺癌细胞中重新表达Slit2和Slit3基因并评估其对肿瘤生长和肿瘤血管生成的影响来探索Slit2和Slit3作为肿瘤抑制因子的作用。 总之，我们已经确定 SDF1/CXCR4 是体内 SLIT/ROBO1 信号传导的关键下游调控靶点。 我们建议阐明该趋化因子轴的失调如何协调细胞与其环境之间的不适当相互作用，从而导致组织和周围微环境的转变。 公共卫生相关性：乳腺癌的起源仍然难以捉摸。 尽管它被认为是一种遗传性疾病，但据估计，所有人类乳腺癌中只有 5-10% 与已知的基因突变有因果关系。 识别其突变导致病变进展并变成恶性的基因对于识别潜在的治疗靶点至关重要。 对于许多癌症（尤其是乳腺癌）来说，G 蛋白偶联受体 CXCR4 是一个在转移中已确定发挥作用的候选靶点。 该应用的目标是使用乳腺作为模型系统来了解 CXCR4 如何促进肿瘤进展。