The Role of glypican-1 in Pancreatic Cancer Development and Progression

描述（由申请人提供）：胰腺导管腺癌（PDAC）是一种高度转移性和生物侵袭性恶性肿瘤，每年在美国造成约34，000例死亡。PDAC具有几种分子改变，包括激活KRAS突变、肿瘤抑制基因p16 INK 4A/p14 ARF的纯合缺失以及肝素结合生长因子及其受体的过表达。此外，磷脂酰肌醇蛋白聚糖-1（GPC 1）是一种细胞表面硫酸乙酰肝素蛋白聚糖（HSPG），由癌细胞释放，由成纤维细胞表达，并在PDAC中过表达。GPC 1增强由几种肝素结合生长因子（HBGF），特别是成纤维细胞生长因子（FGF）、肝素结合EGF样生长因子（HB-EGF）和heregulins激活的信号传导途径。这些HBGF在细胞生长、分化、粘附、转化和转移中起关键作用。此外，GPC 1的抑制在体外消除了响应于HBGF的促有丝分裂信号传导，并在体内减弱了肿瘤生长和转移。这些数据表明，GPC 1不仅在PDAC中过表达，而且宿主来源和癌细胞来源的GPC 1有助于增强肿瘤生长、血管生成和转移。因此，提出了三个具体的目标来检验GPC 1通过增强肿瘤和肿瘤相关基质中的致癌信号传导途径在PDAC进展和转移中起关键作用的假设。首先，将通过一系列旨在评估GPC 1对增殖、迁移和侵袭的影响的机制性体外测定来充分表征从新型转基因小鼠模型Pdx-1-Cre、LSL-KrasG 12 D、INK 4ALox/Lox、GPC 1 +/+或GPCI-/-中分离的肿瘤和原代癌细胞系。接下来，为了描述对GPC 1信号传导功能至关重要的结构组分，将在体外和原位同基因小鼠模型中研究过表达GPC 1的修饰形式的原代癌细胞系。最后，将创建两种转基因小鼠模型，一种是单独过表达GPC 1，另一种是过表达GPC 1与激活的KrasG 12 D结合。这些小鼠模型将用于确定GPC 1对胰腺癌的起始和/或进展的贡献。这项研究不仅将大大提高我们对GPC 1功能的理解，特别是哪些区域对其活性至关重要，而且还将评估GPC 1在胰腺癌肿瘤发展和进展中的重要性。这些数据可以为单独靶向GPC 1或与其他治疗靶点组合靶向GPC 1的功效提供支持。

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic and biologically aggressive malignancy that causes approximately 34,000 deaths in the United States each year. PDAC harbors several molecular alterations including activating KRAS mutations, homozygous deletion of the tumor suppressor gene p16INK4A/p14ARF, and overexpression of heparin binding growth factors and their receptors. In addition, glypican-1 (GPC1), a cell-surface heparan sulfate proteoglycan (HSPG) is released by cancer cells, expressed by fibroblasts, and is over-expressed in PDAC. GPC1 enhances the signaling pathways activated by several heparin binding growth factors (HBGFs), especially fibroblast growth factors (FGFs), heparin binding EGF like growth factor (HB-EGF), and heregulins. These HBGFs play critical roles in cell growth, differentiation, adhesion, transformation and metastasis. Additionally, suppression of GPC1 abrogates mitogenic signaling in response to HBGFs in vitro and attenuates tumor growth and metastasis in vivo. These data indicate that GPC1 is not only overexpressed in PDAC but also that host-derived and cancer cell-derived GPC1 contribute to enhanced tumor growth, angiogenesis, and metastasis. Therefore, three specific aims are proposed to test the hypothesis that GPC1 plays a pivotal role in PDAC progression and metastasis by enhancing oncogenic signaling pathways both in the tumor and within the tumor associated stroma. First, tumors and primary cancer cell lines isolated from the novel transgenic mouse model: Pdx-1-Cre; LSL-KrasG12D; INK4ALox/Lox; GPC1+/+ orGPCI -/-will be fully characterized through a series of mechanistic in-vitro assays desined to assess the impact of GPC1 on proliferation, migration, and invasion. Next, in order to delineate the structural components critical for GPC1 signaling functions, primary cancer cell lines that overexpress modified versions of GPC1 will be studied both in vitro and in an orthotopic syngeneic mouse model. Lastly, two transgenic mouse models will be created, one that overexpresses GPC1 alone and another that overexpresses GPC1 in conjunction with activated KrasG12D. These mouse models will be used to determine GPC1 contribution to the initiation and/or progression of pancreatic adenocarcinomas. This research will not only significantly enhance our understanding of how GPC1 functions, especially what regions are critical for its activity, but it will also assess the importance of GPC1 in tumor development and progression in pancreatic cancer. These data may provide support for the efficacy of targeting GPC1 either alone or in combination with other therapeutic targets.