Mechanisms of Met Induced Hepatocytes Survival

Met诱导肝细胞存活的机制

• 批准号: 8259853
• 负责人: Reza Zarnegar
• 金额: $ 32.89万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-15 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8259853
• 关键词: Active Sites; Address; Albumins; Animals; Antibodies; Apoptosis; Apoptosis Promoter; Apoptotic; Binding; Biochemical; Biological; Biological Assay; C-terminal; Cancer Etiology; Carcinoma; Caspase; Cell Death; Cell Line; Cell Survival; Cell surface; Cells; Complex; Cytoplasmic Tail; Data; Degenerative Disorder; Development; Drug Design; Enhancers; Enzymes; Gene Targeting; Genes; Genetic; Growth; Health; Hepatitis; Hepatocarcinogenesis; Hepatocyte; Human; Induction of Apoptosis; Knock-in Mouse; Liver diseases; Liver neoplasms; Longevity; Malignant Epithelial Cell; Malignant Neoplasms; Measures; Molecular; Molecular Conformation; Mus; Names; National Institute of Diabetes and Digestive and Kidney Diseases; Pancreatic Adenocarcinoma; Peptides; Pharmaceutical Preparations; Phosphotransferases; Physiological; Play; Primary carcinoma of the liver cells; Process; Proteins; Proto-Oncogene Protein c-met; Protocols documentation; Receptor Protein-Tyrosine Kinases; Recombinants; Research; Resistance; Role; Series; Site; Stress; Structure; Tail; Testing; Tissues; Titrations; Transgenic Mice; Tyrosine; adduct; base; cancer cell; caspase-3; cell killing; chemotherapeutic agent; effective therapy; gain of function; in vivo; insight; loss of function; meetings; mutant; novel; overexpression; promoter; research study; thioester; tumor; tumorigenesis

DESCRIPTION (provided by applicant): Escape from apoptosis is a cardinal feature of cancer cells derived from liver tumors and other malignancies. The Hepatocyte Growth Factor Receptor (HGFR) known as Met is a transmembrane receptor tyrosine kinase (RTK) that plays an important role in promoting hepatocyte survival and proliferation, and it is overexpressed in various human carcinoma tissues and cell lines including hepatocellular carcinoma (HCC). Understanding the molecular mechanisms of HCC development is a key NIDDK initiative (i.e., the Action Plan for Liver Disease Research). Using structure-function studies, we discovered that the C-terminal end of human Met's intracellular domain harbors a novel tandem Caspase-3 cleavage site which we named the Met Caspase Decoy Site (MCDS). It has the following sequence: DNAD(DEVD(TRPASFWETS ((denotes the caspase cleavage site). Our central hypothesis to be tested in this A2 Renewal Application is that, by virtue of harboring a unique caspase substrate decoy motif (MCDS), the cytoplasmic tail of human Met functions as a 'bait' and traps the active site of Caspase-3 by forming a stable transition state intermediate during the cleavage process. This results in inhibition of Caspase-3 activity, apoptosis resistance and promotion of HCC. State-of-the-art molecular biochemical and biological approaches are planned to test this intriguing hypothesis. In Aim 1, we will investigate the functional role of the Met Caspase Decoy Site (MCDS) in Caspase-3 inhibition and promotion of hepatocyte survival and hepatocarcinogenesis using loss-of-function and gain-of-function approaches. In Aim 2, we will assess the molecular mechanisms involved in MCDS-Caspase-3 interaction and Caspase-3 inhibition. In Aim 3, we will determine whether MCDS function depends on the activation status of Met. From these studies, we should gather substantial insight into a novel pro-survival mechanism never before described. PUBLIC HEALTH RELEVANCE: Hepatocellular carcinoma (HCC) is the one of most lethal forms of cancer (only second to pancreatic adenocarcinoma). No effective treatment for HCC exists as these tumors are notorious for being resistant to chemotherapeutic agents which kill cells mainly via induction of apoptosis (or programmed cell death). We have discovered that Met, a cancer-causing protein, highjacks the cellular apoptotic machinery (specialized enzymes called caspases) that causes cell death hence contributing to survival and longevity of cancer cells. We will look at the molecular mechanisms of caspase inhibition by Met. Collectively our proposed studies will establish novel insights into the molecular mechanisms of HCC growth and cell survival. They may open avenues for rational drug design (i.e. drugs that mimic Met caspase decoy site) to treat liver diseases ranging from hepatitis to HCC.

描述（由申请人提供）：逃避细胞凋亡是源自肝肿瘤和其他恶性肿瘤的癌细胞的主要特征。肝细胞生长因子受体（HGFR）又称为Met，是一种跨膜受体酪氨酸激酶（RTK），在促进肝细胞存活和增殖中发挥重要作用，在包括肝细胞癌（HCC）在内的多种人类癌组织和细胞系中过度表达。了解 HCC 发展的分子机制是 NIDDK 的一项重要举措（即肝病研究行动计划）。通过结构功能研究，我们发现人 Met 胞内结构域的 C 末端含有一个新的串联 Caspase-3 切割位点，我们将其命名为 Met Caspase 诱饵位点 (MCDS)。它具有以下序列：DNAD(DEVD(TRPASFWETS)（（表示 caspase 裂解位点）。我们在此 A2 更新应用中要测试的中心假设是，凭借具有独特的 caspase 底物诱饵基序 (MCDS)，人 Met 的细胞质尾部起到“诱饵”的作用，并通过形成稳定的结构来捕获 Caspase-3 的活性位点。 裂解过程中的过渡态中间体。这会抑制 Caspase-3 活性、抵抗细胞凋亡并促进 HCC 的发生。计划采用最先进的分子生化和生物学方法来测试这一有趣的假设。在目标 1 中，我们将研究 Met Caspase 诱饵位点 (MCDS) 在 Caspase-3 抑制和促进肝细胞存活和促进肝细胞存活中的功能作用。 使用功能丧失和功能获得方法的肝癌发生。在目标 2 中，我们将评估涉及 MCDS-Caspase-3 相互作用和 Caspase-3 抑制的分子机制。在目标3中，我们将确定MCDS功能是否依赖于Met的激活状态。从这些研究中，我们应该对一种以前从未描述过的新颖的生存机制有深入的了解。 公共卫生相关性：肝细胞癌 (HCC) 是最致命的癌症之一（仅次于胰腺癌）。 HCC 尚无有效的治疗方法，因为这些肿瘤因对主要通过诱导细胞凋亡（或程序性细胞死亡）杀死细胞的化疗药物具有耐药性而臭名昭著。我们发现 Met 是一种致癌蛋白，它会劫持细胞凋亡机制（称为半胱天冬酶的特殊酶），导致细胞死亡，从而有助于癌细胞的存活和长寿。我们将研究 Met 抑制 caspase 的分子机制。总的来说，我们提出的研究将为 HCC 生长和细胞存活的分子机制建立新的见解。它们可能为合理的药物设计（即模仿 Met caspase 诱饵位点的药物）开辟途径，以治疗从肝炎到 HCC 等肝脏疾病。