GLUTAMINE TRANSPORT IN HEPATOCELLULAR TRANSFORMATION

描述：本研究提案的总体目标是研究 谷氨酰胺转运体系统ASC在 肝细胞转化 该提案包含四个具体的 假设：1）通过系统ASC的谷氨酰胺摄取的加速速率是 与人类肝癌的特征一致。 2)ASC介导的谷氨酰胺转运 是必要的，但单独对于肿瘤发生表型是不够的。 第三章 人肝癌的生长通过将谷氨酰胺递送至肿瘤细胞来调节。 细胞质 4)系统ASC活性受细胞生长状态调节。 为了验证这四个假设，研究人员提出了四个具体目标： 1)他们将检查谷氨酰胺在细胞或质膜中的转运 来自手术活检的囊泡，包括肝肿瘤和正常 周围的薄壁组织。 2)一种非致瘤性永生化人肝 上皮细胞系（THLE-5 B）将稳定转染有肝癌 ASC基因转染裸鼠体内评价其致瘤性 潜力 3)人类肝癌和永生化的人类肝细胞将在 在生理谷氨酰胺水平的存在下和在存在或 不存在过量的系统ASC底物和对增殖的影响 评估。 4)ASC介导的谷氨酰胺摄取将在以下两个时间点进行评价： 在同步化肝癌和THLE-5 B细胞中的活性和分子水平 经过营养供应或生化物质的生长调节后。

DESCRIPTION: The overall objective of this research proposal is to study the role and regulation of the glutamine transporter system ASC in hepatocellular transformation. The proposal contains four specific hypotheses: 1) Accelerated rates of glutamine uptake via System ASC are a consistent feature of human hepatomas. 2) ASC mediated glutamine transport is necessary, but not alone sufficient for a tumorigenic phenotype. 3) Growth of human hepatomas is regulated by delivery of glutamine to the cytoplasm. 4) System ASC activity is regulated by cellular growth status. To test these four hypotheses, the investigators propose four specific aims: 1) They will examine glutamine transport in cells or plasma membrane vesicles from surgical biopsies that include hepatic tumor and normal surrounding parenchyma. 2) A nontumorigenic immortalized human liver epithelial cell line (THLE-5B) will be stably transfected with the hepatoma ASC gene and injected into nude mice for evaluation of tumorigenic potential. 3) Human hepatomas and immortalized human liver cells will be grown in the presence of physiologic glutamine levels and in the presence or absence of excess System ASC substrates and the effects on proliferation evaluated. 4) ASC mediated glutamine uptake will be evaluated at both the activity and molecular levels in synchronized hepatoma and THLE-5B cells after growth modulation by nutrient supply or biochemicals.