The Role of TIMPs in Cell Growth and Differentiation: Tumor Angiogenesis

TIMP 在细胞生长和分化中的作用：肿瘤血管生成

• 批准号: 8350064
• 负责人: William Stetler-Stevenson
• 金额: $ 64.29万
• 依托单位: DIVISION OF CLINICAL SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8350064
• 关键词: 3-Dimensional; A549; Amino Acid Sequence; Amino Acids; Antibodies; Apoptotic; Basement membrane; Behavior; Binding; Biochemical; Biological; Biology; Breast Cancer Cell; Cancer cell line; Cell Differentiation process; Cell Line; Cell Surface Receptors; Cells; Chemicals; Chronic Disease; Complex; Cues; Development; EGF gene; Elements; Endothelial Cells; Epidermal Growth Factor Receptor; Evolution; Excision; Extracellular Matrix; Family; Fibroblast Growth Factor; Fibroblast Growth Factor 2; Fibroblasts; Future; Gene Expression; Genes; Goals; Growth; Growth Factor; Growth Factor Receptors; Homeostasis; Human; Immune response; In Vitro; Inflammation; Inhibition of Matrix Metalloproteinases Pathway; Injection of therapeutic agent; Integrin Binding; Integrin alpha3beta1; Integrins; Kaposi Sarcoma; Laboratories; Lead; Malignant - descriptor; Malignant Epithelial Cell; Malignant Neoplasms; Malignant neoplasm of lung; Matrix Metalloproteinases; Mediating; Mus; Mutation; N-terminal; Neoplasm Metastasis; Non-Malignant; Normal Cell; Normal tissue morphology; Oncogenes; Organ; Organism; Pathway interactions; Peptides; Phenotype; Phosphorylation; Play; Primary Neoplasm; Process; Protein Tyrosine Phosphatase; Proteins; Reagent; Receptor Activation; Receptor Protein-Tyrosine Kinases; Receptor Signaling; Recombinants; Regulation; Relative (related person); Role; Signaling Molecule; Site; Solvents; Stimulation of Cell Proliferation; Structure; Teratocarcinoma; Therapeutic; Tissue Inhibitor of Metalloproteinase-1; Tissue Inhibitor of Metalloproteinases; Tissues; Tumor Angiogenesis; Tumor Cell Invasion; Tumor Suppression; Tumor Suppressor Genes; Tumor Suppressor Proteins; Vascular Endothelial Growth Factor Receptor-2; Vascular Endothelial Growth Factors; Work; Xenograft Model; angiogenesis; base; blastocyst; cancer therapy; cell behavior; cell growth; cell type; cytokine; epithelial to mesenchymal transition; extracellular; fibrosarcoma; flexibility; human tissue; in vivo; in vivo Model; lung Carcinoma; member; metastatic process; neoplastic cell; new therapeutic target; novel; novel therapeutics; overexpression; precursor cell; pressure; protein aminoacid sequence; receptor; research study; response; synthetic peptide; tumor; tumor growth; tumor progression; tumorigenic

Summary: EGF-stimulation of the A549 human lung carcinoma cell line demonstrated that the suppression of cell growth response was mediated by the activation of protein tyrosine phosphatase activity and resulted in reduced EGF receptor phosphorylation. Competition binding experiments using anti-integrin antibodies identified integrin alpha3beta1 as a putative cell surface receptor for TIMP-2 on human microvascular endothelial cells (hMVECs). Ala+TIMP-2 also inhibited VEGF-A or FGF-2 stimulated mitogenesis in vitro and angiogenesis in vivo a, thus demonstrating that the angio-inhibitory activity of TIMP-2 is dissociable from MMP-inhibition. The mechanism of this effect involves an integrin receptor inactivation of growth factor receptor signaling, known as heterologous receptor inactivation. This was the first demonstration that integrins could negatively regulate activation of a receptor tyrosine kinase This work has defined a new paradigm for TIMP biology by demonstrating that TIMPs are multifunctional proteins, with cell surface receptors and through interaction with these receptors they can directly influence cellular behavior. Using both in vitro and in vivo models our current and future work is focused on identifying the alpha3beta1 integrin binding domain(s) in TIMP-2 and furthering our understanding of the cellular effects following TIMP-2 interaction with alpha3beta1 in both normal and neoplastic cells, as well as the subsequent alterations in the tumor microenvironment. It is our goal to further characterize the MMP-independent and MMP-dependent effects of TIMPs in the tumor microenvironment and their relative contribution to tumor suppression and/or progression. These studies should identify crucial mechanisms in the regulation of cell behavior by the extracellular matrix in normal tissues and the tumor microenvironment, and possibly lead to new therapeutic strategies for cancer treatment. These findings suggest that defining the domain(s) responsible for TIMP-2-binding to alpha3beta1 will be critical to further dissecting the multiple biological activities of this complex molecule, as well as defining the functional contributions of this activity to the microenvironment in both normal and malignant tissues. The focus of this project is to determine the mechanisms of the anti-angiogenic and anti-tumorigenic effects of Ala+TIMP-2. Preliminary work with human microvascular endothelial cells has demonstrated a mechanism known as heterologous receptor inactivation. In this effect the TIMP-2 receptor alpha3beta1 decreases phosphorylation and activation of receptor tyrosine kinases such as the vascular endothelial growth factor receptor (VEGFR)-2, fibroblast growth factor recetpor (FGFR)-1 and epidermal growth factor receptor (EGFR) by activation a phosphotyrosine phosphatase known as Shp-1. However, recent experiments in tumor cells and endothelial cells have revealed that the growth suppressor activity of Ala+TIMP-2 is more complex and appears to involve apoptotic pathways and changes in gene expression of the epithelial to mesenchymal transition that is essential to tumor invasion and metastasis. It is the purpose of this project to identify and delineate these pathways with the aim of developing Ala+TIMP-2 as a novel cancer therapeutic and identifying potential new therapeutic targets. Tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits angiogenesis by several mechanisms involving either MMP inhibition or direct endothelial cell binding. The primary aim of this study was to identify the TIMP-2 region involved in binding to the previously identified receptor integrin alpha3beta1, and to determine whether synthetic peptides derived from this region retained angio-inhibitory and tumor suppressor activity. We demonstrated that the N-terminal domain of TIMP-2 (N-TIMP-2) binds to alpha3beta1 and inhibits vascular endothelial growth factor-stimulated endothelial cell growth in vitro, suggesting that both the alpha3beta1-binding domain and growth suppressor activity of TIMP-2 localize to the N-terminal domain. Using a peptide array approach we identify a 24 amino acid region of TIMP-2 primary sequence, consisting of residues Ile43-Ala66, which shows alpha3beta1-binding activity. Subsequently we demonstrate that synthetic peptides from this region compete for TIMP-2 binding to alpha3beta1 and suppress endothelial growth in vitro. We define a minimal peptide sequence (peptide 8-9) that posses both angio-inhibitory and, using a murine xenograft model of Kaposis sarcoma, anti-tumorigenic activity in vivo. Thus, both the alpha3beta1-binding and angio-inhibitory activities co-localize to a solvent exposed, flexible region in the TIMP-2 primary sequence that is unique in amino acid sequence compared with other members of the TIMP family. Furthermore, comparison of the TIMP-2 and TIMP-1 protein 3-D structures in this region also identified unique structural differences. Our findings demonstrate that the integrin binding, tumor growth suppressor and in vivo angio-inhibitory activities of TIMP-2 are intimately associated within a unique sequence/structural loop (B-C loop).

总结：EGF刺激A549人肺癌细胞系表明，细胞生长反应的抑制是由蛋白质酪氨酸磷酸酶活性的激活介导的，并导致EGF受体磷酸化减少。使用抗整联蛋白抗体的竞争结合实验将整联蛋白α 3 β 1鉴定为人微血管内皮细胞（hMVEC）上TIMP-2的推定细胞表面受体。Ala+TIMP-2还抑制VEGF-A或FGF-2刺激的体外有丝分裂和体内血管生成，从而证明TIMP-2的血管抑制活性与MMP抑制无关。这种效应的机制涉及生长因子受体信号传导的整联蛋白受体失活，称为异源受体失活。这是第一次证明整合素可以负调节受体酪氨酸激酶的激活。这项工作通过证明TIMP是多功能蛋白质，具有细胞表面受体，并通过与这些受体的相互作用，它们可以直接影响细胞行为，为TIMP生物学定义了一个新的范例。使用体外和体内模型，我们目前和未来的工作重点是确定TIMP-2中的α 3 β 1整合素结合结构域，并进一步了解TIMP-2与正常和肿瘤细胞中的α 3 β 1相互作用后的细胞效应，以及随后的肿瘤微环境改变。我们的目标是进一步表征TIMP在肿瘤微环境中的MMP非依赖性和MMP依赖性作用及其对肿瘤抑制和/或进展的相对贡献。这些研究应该确定正常组织和肿瘤微环境中细胞外基质调节细胞行为的关键机制，并可能导致癌症治疗的新治疗策略。这些发现表明，确定负责TIMP-2与α 3 β 1结合的结构域对于进一步剖析这种复杂分子的多种生物活性以及确定这种活性对正常和恶性组织中微环境的功能贡献至关重要。本课题的重点是研究Ala+TIMP-2的抗血管生成和抗肿瘤作用的机制。对人类微血管内皮细胞的初步研究已经证明了一种称为异源受体失活的机制。在这种作用中，TIMP-2受体α 3 β 1通过激活称为Shp-1的磷酸酪氨酸磷酸酶来降低受体酪氨酸激酶如血管内皮生长因子受体（VEGFR）-2、成纤维细胞生长因子受体（FGFR）-1和表皮生长因子受体（EGFR）的磷酸化和激活。然而，最近在肿瘤细胞和内皮细胞中的实验已经揭示，Ala+TIMP-2的生长抑制活性更复杂，并且似乎涉及凋亡途径和上皮向间充质转化的基因表达的变化，上皮向间充质转化是肿瘤侵袭和转移所必需的。本项目的目的是鉴定和描述这些通路，旨在开发Ala+TIMP-2作为一种新型癌症治疗剂，并鉴定潜在的新治疗靶点。金属蛋白酶组织抑制剂-2（TIMP-2）通过几种机制抑制血管生成，包括MMP抑制或直接内皮细胞结合。本研究的主要目的是鉴定与先前鉴定的受体整合素α 3 β 1结合的TIMP-2区域，并确定来自该区域的合成肽是否保留血管抑制和肿瘤抑制活性。我们证明，N-末端结构域的TIMP-2（N-TIMP-2）结合α 3 β 1，并抑制血管内皮生长因子刺激的内皮细胞生长在体外，这表明α 3 β 1结合结构域和生长抑制活性的TIMP-2本地化的N-末端结构域。使用肽阵列方法，我们确定了TIMP-2的一级序列的24个氨基酸的区域，由残基Ile 43-Ala 66组成，其显示出α 3 β 1结合活性。随后，我们证明，从这个区域的合成肽竞争TIMP-2结合到alpha 3 β 1和抑制内皮细胞生长在体外。我们定义了一个最小的肽序列（肽8-9），它在体内既具有血管抑制活性，又具有抗肿瘤活性（使用卡波西肉瘤的鼠异种移植模型）。因此，α 3 β 1结合和血管抑制活性共定位于TIMP-2一级序列中暴露于溶剂的柔性区域，与TIMP家族的其他成员相比，该区域在氨基酸序列上是独特的。此外，比较TIMP-2和TIMP-1蛋白在该区域的3-D结构也确定了独特的结构差异。我们的研究结果表明，整合素结合，肿瘤生长抑制剂和TIMP-2的体内血管抑制活性是密切相关的一个独特的序列/结构环（B-C环）。