BIOLOGY AND PATHOLOGY OF A MODULATOR OF FGF

FGF 调节剂的生物学和病理学

基本信息

批准号：
2010054
负责人：
Anton Wellstein
金额：
$ 10.39万
依托单位：
GEORGETOWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1997
资助国家：
美国
起止时间：
1997-06-01 至 2000-05-31
项目状态：
已结题

项目摘要

Acidic or basic fibroblast growth factors (FGF) are present at significant concentrations in most normal tissues in the adult, can stimulate angiogenesis and thus have the potential to play an important role during tumor growth and metastasis. However, both of these FGFs are immobilized in an inactive state on the extracellular matrix and it is only poorly understood how they are solubilized and activated to reach their extracellular receptors. One mechanism through which these growth factors can be mobilized is by binding to a secreted binding protein for FGF (BP) that was described by Wu et al in 1991. In recent work from our laboratory, we detected high levels of BP mRNA in majority of squamous cell cancer (SCC) samples from patients and in SCC cell lines in culture. On the other hand, we did not detect BP mRNA in normal adult human tissues or in normal adult rodent tissues as well as in a series of cultured cell lines that were not of squamous origin. In contrast with the lack of expression of BP in adult tissues, we found BP mRNA highly expressed in murine embryonic squamous epithelia of the lungs and skin during late gestation. In functional studies with non-tumorigenic cells (SW-13), we demonstrated that expression of BP can mobilize and activate bFGF leading to tumor growth and angiogenesis of the BP- transfected cells. Furthermore, in an SCC cell line expressing high levels of BP mRNA, reduction of BP expression using BP-targeted ribozymes reduced tumor growth and angiogenesis of xenografts of these cells in athymic nude mice. This suggests a potentially rate- limiting role of this protein for SCC tumor growth in vivo. In addition, we found that retinoids downregulate BP mRNA rapidly through a posttranscriptional mechanism. We propose the following experiments to study the role of BP in tumor growth as well as the mechanism(s) and therapeutic significance of its downregulation by retinoids: Under AIM 1, we will express BP in cell lines which have a low tumorigenic potential and are negative for BP and study phenotypic changes. The expression of BP will be under the control of a tetracycline- regulated promoter that allows to regulate transfected BP in vitro or in vivo by administration of tetracycline. Under AIM 2, we will use molecular targeting of BP mRNA with ribozymes to elucidate the contribution of BP to tumor growth of cell lines that express BP. Under AIM 3, we will study the mechanism(s) of retinoid regulation of BP with respect to receptor subtype and the retinoid- dependent target site in the BP mRNA. Furthermore, we will study to what extent downregulation of BP by retinoids contributes to the effect of these drugs on SCC tumors.

酸性或碱性成纤维细胞生长因子 (FGF) 存在于成人大多数正常组织中的显着浓度，可以刺激血管生成，从而有可能发挥作用在肿瘤生长和转移过程中发挥重要作用。然而，这两种 FGF 均以非活性状态固定在细胞外基质，但人们对它们的构成知之甚少溶解并激活以到达其细胞外受体。这些生长因子可以通过一种机制通过与 FGF (BP) 的分泌性结合蛋白结合来动员 Wu 等人于 1991 年描述了这一点。在我们实验室最近的工作中，我们检测到高水平的血压大多数鳞状细胞癌 (SCC) 样本中的 mRNA 患者和培养的 SCC 细胞系中。另一方面，我们未在正常成人组织或组织中检测到 BP mRNA 正常成年啮齿动物组织以及一系列培养细胞非鳞状起源的线。与缺乏相比 BP在成人组织中的表达，我们发现BP mRNA高度在小鼠胚胎肺鳞状上皮细胞中表达和妊娠后期的皮肤。在非致瘤细胞 (SW-13) 的功能研究中，我们证明 BP 的表达可以动员和激活 bFGF 导致肿瘤生长和 BP-血管生成转染的细胞。此外，在表达高 BP mRNA 水平，使用 BP 靶向降低 BP 表达核酶减少异种移植物的肿瘤生长和血管生成这些细胞来自无胸腺裸鼠。这表明潜在的利率- 该蛋白对 SCC 肿瘤体内生长的限制作用。在此外，我们发现类视黄醇快速下调 BP mRNA 通过转录后机制。我们提出以下实验来研究 BP 在肿瘤生长以及机制和治疗类维生素A下调其意义：在AIM 1下，我们将在具有低致瘤潜力的细胞系中表达 BP BP 和研究表型变化均为阴性。这 BP的表达将受到四环素的控制受调节的启动子，允许在体外调节转染的血压或通过给予四环素在体内进行。根据 AIM 2，我们将使用核酶对 BP mRNA 进行分子靶向来阐明 BP 对表达的细胞系肿瘤生长的贡献血压。在AIM 3下，我们将研究类维生素A的机制与受体亚型和类维生素A有关的血压调节 BP mRNA 中的依赖靶位点。此外，我们将研究类维生素A在多大程度上下调血压来了解这些药物对 SCC 肿瘤的作用。