Role of Glypican-1 in Pancreatic Cancer

描述（由申请人提供）：胰腺导管腺癌（pdac）过度表达多种酪氨酸激酶受体，如I型FGF受体（FGFR-1）及其配体。这些配体中有许多是肝素结合生长因子（HBGFs），其有丝分裂作用通常依赖于与硫酸肝素蛋白聚糖（HSPGs）的相互作用，后者促进配体与高亲和力受体的结合。我们已经确定，PDAC过表达glypican-1，但其他5个glypican家族成员的表达水平不高，这表明glypican-1可能在PDAC中具有独特而重要的作用。然而，glypcian-1在PDAC中的确切作用及其作用机制尚不清楚。因此，我们将使用4种互补的方法来验证glypican-1在PDAC中至关重要的假设，以及它通过促进有丝分裂、侵袭和/或转移而起作用。我们将首先检查glypican-1表达是否与肿瘤分级、分期或患者生存率相关。其次，我们将建立过表达glypican-1的胰腺癌细胞系，以及glypican-1表达被glypican-1反义结构抑制的细胞系，以便在适当的体外和体内模型系统中评估glypican-1在癌细胞生长、侵袭和转移中的作用。第三，我们将确定glypican-1的致瘤作用是否会因I型成纤维细胞生长因子受体（FGFR-1）的存在而增强，因为该受体在PDAC中过表达，并被多个hbgf激活。为此，我们将在缺乏或存在两种主要FGFR-1亚型的情况下，用编码glypican-1的cdna转染培养的人胰腺导管细胞。第四，我们将通过检测glypican-1的糖基化状态及其与FGFR复合物的相互作用，以及通过设计各种glypican-1嵌合蛋白并将其作用与野生型glypican-1的作用进行比较，探索glypican-1赋予培养胰腺癌细胞生长优势的机制。总之，这些研究将有助于阐明glypican-1在PDAC中的作用。

DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinomas (PDACs) overexpress multiple tyrosine kinase receptors such as the type I FGF receptor (FGFR-1), and their ligands. Many of these ligands are heparin-binding growth factors (HBGFs), whose mitogenic actions are often dependent on interactions with heparan sulfate proteoglycans (HSPGs) that facilitate ligand binding to high affinity receptors. We have determined that PDACs overexpress glypican-1 but de not express high levels of other 5 members of the glypican family, raising the possibility that glypican-1 may have a unique and important role in PDAC. However, the exact role of glypcian-1 in PDAC and its mechanisms of action are not well understood. Therefore, we will use 4 complementary approaches to test the hypothesis that glypican-1 is of paramount importance in PDAC and that it acts by promoting mitogenesis, invasion and/or metastasis. We will first examine whether glypican-1 expression correlates with tumor grade and stage, or patient survival. Second, we will establish pancreatic cancer cell lines that overexpress glypican-1, as well as cell lines whose glypican-1 expression is suppressed by a glypican-1 antisense construct, in order to assess the role of glypican-1 in cancer cell growth, invasion, and metastasis in appropriate in vitro and in vivo model systems. Third, we will determine whether any tumorigenic effects of glypican-1 are enhanced by the presence of the type I fibroblast growth factor receptor (FGFR-1), since this receptor is overexpressed in PDAC and is activated by multiple HBGFs. To this end, we will transfect cultured human pancreatic ductal cells with cDNAs encoding glypican-1 in the absence or presence of the two major FGFR-1 isoforms. Fourth, we will explore the mechanisms whereby glypican-1 confers a growth advantage to cultured pancreatic cancer cells by examining its glycanation status and its interactions with FGFR complexes, and by engineering various glypican-1 chimeric proteins and comparing their actions with the actions of wild type glypican-1. Together, these studies will help to elucidate the role of glypican-1 in PDAC.