EFGR and Esophageal Proliferation

描述（申请人提供）：食管癌是美国和世界范围内常见的恶性肿瘤。多项研究表明，食管鳞状细胞癌（ESCC）的分子基础涉及癌基因和抑癌基因的激活，但表皮生长因子受体（EGFR）在癌变早期的作用尚不明确。我们通过逆转录病毒介导的转导在不同的原代人食管上皮细胞中过表达EGFR。这导致观察到EGFR调节的增强细胞迁移有协调的后果。此外，当将过表达EGFR的人食管上皮细胞置于一种新型的器官型细胞培养系统中时，会诱导上皮细胞厚度增加、增生和过度增殖。我们的假设是，EGFR通过诱导过度增殖和增强细胞迁移并损害分化，在破坏正常细胞稳态中起关键作用。这些目标将通过以下相关的具体目标来实现：(1)确定EGFR对Akt的功能激活，并确定STAT-1上调与基质金属蛋白酶（MMPs）作为细胞迁移调节剂之间的可能联系；(2)阐明EGFR通过诱导RAD （ras样分子）促进细胞增殖的作用，RAD是一种GTP结合蛋白，受nm-23转移抑制基因的负调控。通过对用绿色荧光蛋白（GFP）与EGFR逆转录病毒转导的食管上皮细胞进行基因阵列比较，发现RAD表达上调。

DESCRIPTION (provided by applicant): Esophageal cancer is a common malignancy in the United States and worldwide. A number of studies indicate that the molecular basis of esophageal squamous cancer cell carcinoma (ESCC) involves the activation of oncogenes and tumor suppressor genes, but the role of epidermal growth factor receptor (EGFR) in the very early stages of carcinogenesis remains elusive. We have overexpressed EGFR through retro-virally-mediated transduction in different primary human esophageal epithelial cells. This has led to observations that there are coordinated consequences of enhanced cell migration modulated by EGFR. In addition, when EGFR overexpressing primary human esophageal epithelial cells are placed in a novel, organotypic cell culture system, there is induction of increased epithelial thickness, hyperplasia, and hyperproliferation. Our hypothesis is that EGFR plays a critical role in the disruption of normal cellular homeostasis through induction of hyperproliferation and enhanced cell migration with impairment of differentiation. The objectives will be achieved through the following interrelated Specific Aims: (1) To determine the functional activation of Akt by EGFR and determine the possible link between upregulation of STAT-1 and matrix metalloproteinases (MMPs) as modulators of cell migration and (2) To elucidate the role of EGFR in promoting increased cell proliferation through the induction of RAD (ras like molecule), a GTP binding protein that is negatively regulated by the nm-23 metastasis suppressor gene. RAD was found to be upregulated based upon a gene array comparison of esophageal epithelial cells retrovirally transduced with green fluorescent protein (GFP) versus EGFR. In aggregate, the proposed studies will provide new insights into EGFR signaling and modulation of key cellular processes in the esophageal epithelium as the basis for the very early steps in esophageal squamous carcinogenesis. These data will provide a foundation for future studies in transgenic mouse models and a transition towards an R01 grant proposal.