Alternatively Spliced Tissue Factor and Pathobiology of Pancreatic Cancer

描述(申请人提供)：我们建议评估最近发现的一种被称为选择性剪接组织因子(AsTF)的蛋白质是否可以导致开发新的抗击胰腺癌的策略，特别是胰腺导管腺癌(PDAC)，这是一种高度致命的癌症，也是一种主要的治疗挑战。ASTF在PDAC中的表达增加，并促进单核细胞募集、PDAC细胞的增殖和迁移、耐缺氧、转移扩散和血管生长。我们推测，asTF作为一种非蛋白水解性细胞激动剂，可以促进PDAC的生长和扩散，因为它在肿瘤间质中积聚。本研究的主要目的有三个方面：1.确定S的活动领域 与β1整合素结合并通过β1整合素传递信号所需的人asTF。ASTF作为整合素的配体/激活剂，在非规范区域与β1整合素结合。我们将通过产生重组asTF突变体，在体外评估所产生的表型(S)，然后将它们在PDAC细胞中表达，以证实我们的发现，从而定位通过Beta1整合素传递信号所需的asTF结构域(S)。2.确定肿瘤来源的asTF与宿主来源的asTF在PDAC进展中的作用。这一目标的理论基础是基于这样一种假设，即肿瘤细胞和间质单核细胞表达的asTF促进了PDAC细胞的增殖、单核细胞的募集和已建立的转移瘤的侵袭性生长。我们将使用一套独特的工具(细胞系、转基因小鼠和创新的成像技术)来评估 肿瘤细胞来源的asTF和宿主细胞来源的astf在PDAC进展中的相对贡献。3.探讨抑制性抗AsTf单抗Rb1治疗PDAC的可能性。我们建立了人PDAC肿瘤标本在裸鼠体内生长的方法，并研制了一种抑制性抗人asTF单抗Rb1，它能在体外减少PDAC细胞的迁移，并在体内抑制PDAC细胞的生长。我们将评估全身给药Rb1抑制人PDAC细胞和患者来源的PDAC肿瘤移植瘤生长的能力，以及Rb1‘S诱导免疫细胞和补体介导的细胞毒作用的潜力。完成后，我们的研究很有可能：1)对asTF在PDAC进展中的作用产生新的见解，这可能为治疗PDAC开辟新的途径；2)阐明β1整合素信号在PDAC发病机制中的意义；3)加深对单核/巨噬细胞在PDAC病理生物学中所起作用的理解(S)。

DESCRIPTION (provided by applicant): We propose to evaluate whether a recently discovered protein termed alternatively spliced Tissue Factor (asTF) can lead to the development of new strategies to fight pancreatic cancer, specifically pancreatic ductal adenocarcinoma (PDAC), a highly lethal form of cancer and a major therapeutic challenge. asTF expression is increased in PDAC and it enhances monocyte recruitment, PDAC cell proliferation and migration, resistance to hypoxia, metastatic spread, and vessel growth. We posit that asTF enhances PDAC growth and spread as it accrues in tumor stroma, acting as a non-proteolytic cell agonist. To study asTF's mode(s) of action in PDAC and evaluate its potential utility as a target, we propose the following three Aims: 1. To identify the domain(s) of human asTF required for binding to, and signaling via beta1 integrins. asTF binds beta1 integrins in a non-canonical region, acting as an integrin ligand/activator. We will map asTF domain(s) required to signal via beta1 integrins by generating recombinant asTF mutants, assessing the resultant phenotype(s) in vitro, and then expressing them in PDAC cells to confirm our findings in vivo. 2. To determine the contribution of tumor-derived versus host- derived asTF to PDAC progression. Rationale for this Aim is grounded in the hypothesis that asTF expressed by tumor cells as well as stromal monocytes fuels PDAC cell proliferation, monocyte recruitment, and aggressive growth of established metastases. We will use a unique set of tools (cell lines, genetically modified mice, and innovative imaging technologies) to assess the relative contribution of tumor cell-derived asTF, and host cell-derived asTF to PDAC progression. 3. To investigate the potential utility of the inhibitory anti-asTF monoclonal antibod Rb1 to treat PDAC. We established the procedure for growing human PDAC tumor specimens in nude mice, and developed an inhibitory anti-human asTF monoclonal antibody Rb1 that reduces migration of PDAC cells in vitro, and suppresses PDAC cell growth in vivo. We will assess the ability of systemically administered Rb1 to reduce the growth of human PDAC cells and patient-derived PDAC tumor xenografts, and Rb1's potential to induce immune cell- and complement-mediated cytotoxicity. Upon completion, our studies are highly likely to i) yield new insights into the role of asTF in PDAC progression, which may open new avenues to treat PDAC, ii) elucidate the significance of beta1 integrin signaling in PDAC pathogenesis, and iii) improve understanding of the role(s) played by monocytes/macrophages in PDAC pathobiology.