CTGF in Pancreatic Tumor Growth

描述（由申请人提供）：在上一次资助期间，我们获得的证据表明，结缔组织生长因子（CTGF）的表达在人类胰腺肿瘤中升高，但在正常胰腺或胰腺炎中不升高。由于胰腺肿瘤是高度缺氧和CTGF是已知的缺氧诱导，我们已经集中在这个赠款，以了解缺氧和CTGF在胰腺肿瘤进展的作用。研究CTGF在胰腺肿瘤进展中的重要性的这些研究的基础来自我们的证明，即用单克隆特异性抗体靶向抑制CTGF导致作为皮下肿瘤植入的两种不同胰腺癌细胞系的显著生长抑制。在这项研究中，我们将重点研究CTGF及其各个结构域在常氧和低氧条件下对胰腺肿瘤进展的机制作用。我们的初步数据表明CTGF能够促进胰腺肿瘤细胞的生长。CTGF的诱导对细胞在塑料上的生长没有影响，但在软琼脂上显著增强了球状体的生长。最引人注目的是CTGF表达诱导的细胞粘附增加。细胞粘附的这些变化是必要的3-D生长导致我们测试的假设，CTGF在恶性进展的主要作用之一是调节细胞-细胞粘附，抑制这种活性将影响肿瘤的生长和转移。因此，本发明的目的是1）确定CTGF如何在常氧和低氧条件下影响胰腺肿瘤细胞的细胞粘附，使用被操纵以表达不同水平的HIF-1的细胞中的结构域特异性缺失突变体，2）确定CTGF对于常氧和低氧条件下的3-D生长和侵袭有多重要，3）确定CTGF介导的粘附的抑制如何影响转移性生长，4）确定CTGF对细胞粘附的抑制如何影响胰腺肿瘤细胞的皮下和原位肿瘤生长，5）确定间质细胞和肿瘤细胞CTGF对肿瘤生长的作用，6）确定CTGF Ab和电离辐射或吉西他滨的组合与单独的电离辐射或吉西他滨相比在控制胰腺肿瘤生长中的有效性。总之，拟议的研究旨在解决CTGF影响胰腺癌肿瘤进展的重要机制，并确定其在联合治疗中的有效性，以将其推向临床。

DESCRIPTION (provided by applicant): During the last grant period, we have obtained evidence that the expression of connective tissue growth factor (CTGF) is elevated in human pancreatic tumors, but not in normal pancreas or pancreatitis. Since pancreatic tumors are highly hypoxia and CTGF is known to be hypoxia inducible, we have focused this grant to understand the role of hypoxia and CTGF in pancreatic tumor progression. The basis for these studies to investigate the importance of CTGF in pancreatic tumor progression derive from our demonstration that targeted inhibition of CTGF with a monoclonal specific antibody results in significant growth inhibition of two different pancreatic cancer cell lines implanted as subcutaneous tumors. In this grant, we will focus on determining the mechanistic role of CTGF and its individual domains on pancreatic tumor progression under normoxic and hypoxic conditions. Our preliminary data suggests that CTGF is able to enhance the growth of pancreatic tumor cells. Induction of CTGF had no effect on cell growth on plastic, but significantly enhanced spheroid growth in soft agar. Most striking was the increase in cell adhesion induced by CTGF expression. These changes in cell adhesion that are necessary for 3-D growth lead us to test the hypothesis that one of the major roles of CTGF in malignant progression is to regulate cell-cell adhesion, and that inhibiting this activity will impact tumor growth and metastases. Thus, the aims of this proposal are to 1) determine how CTGF affects cell adhesion of pancreatic tumor cells under normoxic and hypoxic conditions using domain specific deletion mutants in cells that are manipulated to express different levels of HIF-1, 2) determine how important CTGF is for 3-D growth and invasion under normoxic and hypoxic conditions, 3) determine how inhibition of CTGF mediated adhesion affects metastatic growth, 4) determine how inhibition of cell adhesion by CTGF affects subcutaneous and orthotopic tumor growth of pancreatic tumor cells, 5) determine the role of stromal and tumor cell CTGF on tumor growth, 6) determine how effective the combination of CTGF Ab and ionizing radiation or gemcitabine are in controlling pancreatic tumor growth compared to ionizing radiation or gemcitabine alone. In summary, the proposed studies are intended to address an important mechanism by which CTGF affects tumor progression in pancreatic cancers and to determine how effective it is in combination therapy to bring it to the clinic.