REGULATION OF BENIGN AND MALIGNANT HEPATOCYTE GROWTH

良性和恶性肝细胞生长的调节

• 批准号: 6790510
• 负责人: IAIN HUGH MCKILLOP
• 金额: $ 18.53万
• 依托单位: UNIVERSITY OF NORTH CAROLINA CHARLOTTE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-06 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6790510
• 关键词: G protein; athymic mouse; biological signal transduction; cAMP response element binding protein; cell growth regulation; cell line; cell membrane; cell proliferation; cellular oncology; disease /disorder etiology; enzyme linked immunosorbent assay; flow cytometry; fluorescence microscopy; gel mobility shift assay; hepatocellular carcinoma; insulinlike growth factor; laboratory rat; mitogen activated protein kinase; neoplasm /cancer pharmacology; neoplastic growth; neoplastic transformation; northern blottings; receptor expression; tissue /cell culture; transfection; western blottings

DESCRIPTION (provided by applicant): Hepatocellular cancer (HCC) leads to the death of more than 35,000 Americans annually in addition to being one of the leading causes of cancer death worldwide. Surgical resection is the best treatment available to patients with HCC but is a viable option for only 20-40% of those diagnosed. The failure to develop alternative treatments for HCC is due to our lack of understanding of the disease etiology at the cellular and molecular level. Previous reports from our laboratory have identified components of a mitogen activated protein kinase (MAPK) cascades as a focal point in processing signals of diverse origin including those associated with guanine nucleotide regulatory protein (C-protein) coupled and tyrosine kinase-linked receptors. Specifically, we have demonstrated altered expression and function of inhibitory G-proteins (Giproteins) in more than 80% of human HCC analyzed. Furthermore, activation of Gi-proteins in human and animal models of HCC leads to enhanced mitogenesis via a mitogen activated protein kinase (MAPK) cascade, an effect not observed in non-transformed hepatocytes. Other data from our laboratory demonstrate changes in hepatic insulin-like growth factor-I (IGF-l) expression in HCC and non-tumorigenic, histologically normal hepatic tissue in tumor burdened animals. Stimulation of HCC cells with IGF-l leads to increased cell mitogenesis via a MAPK pathway, an effect abrogated by inhibition of Gi-protein signaling.Based on these observations the central hypothesis of this proposal is that a MAPK cascade represents a focal link between transmembrane signals of diverse origin, regulation of which directly affects hepatic tumor proliferation at multiple levels and is intrinsically linked to the increased cell mitogenesis characteristic of HCC. It is the aim of this NIH-R01 First Award to "determine the mechanisms by which MAPK components regulate cell mitogenesis at the membrane, cytoplasmic and nuclear levels." Specifically we will (i) over-express constitutively active or dominant negative components of G-protein/IGF-l-MAPK signaling pathways in conjunction with specific pharmacological agents that stimulate or inhibit these pathways. These data will determine the role of C-protein subunits and TK-linked receptors and their associated second messengers in regulating cytoplasmic (MAPK) signaling pathways in HCC. (ii) determine the role of G-protein/IGF-l-MAPK pathways in regulating nuclear transcription factors and cell proliferation and survival in normal and transformed (HCC) hepatocytes.Because the mortality associated with HCC is so high, deciphering the mechanisms by which cell growth and tumor progression occurs is clearly of major clinical importance and significance. Accordingly, elucidation of the mechanisms controlling cell proliferation at the cytoplasmic and nuclear level represents a potential breakthrough in the development of new treatments for non-resectable HCC.

描述（由申请人提供）：肝细胞癌（HCC）除了成为全球癌症死亡的主要原因之一外，每年导致35,000多名美国人死亡。手术切除是HCC患者可用的最佳治疗方法，但对于被诊断的患者的20-40％是可行的选择。无法开发HCC的替代治疗方法是由于我们对细胞和分子水平上疾病病因的了解不足。我们实验室的先前报道已经确定了有丝分裂原活化蛋白激酶（MAPK）级联反应的成分是处理多种起源信号的焦点，包括与鸟嘌呤核苷酸调节蛋白（C蛋白）耦合的核苷酸调节蛋白（C蛋白）和酪氨酸激酶链接受体相关的焦点。具体而言，我们已经证明了在超过80％的人类HCC分析中，抑制性G蛋白（Giprotein）的表达和功能改变了。此外，HCC人类和动物模型中GI-蛋白的激活导致通过有丝分裂原活化蛋白激酶（MAPK）级联反应增强有丝分裂的作用，这在未转化的肝细胞中未观察到这种作用。来自我们实验室的其他数据表明，在肿瘤负担的动物中，HCC和非肿瘤，组织学正常肝组织的肝胰岛素样生长因子I（IGF-L）表达的变化。 Stimulation of HCC cells with IGF-l leads to increased cell mitogenesis via a MAPK pathway, an effect abrogated by inhibition of Gi-protein signaling.Based on these observations the central hypothesis of this proposal is that a MAPK cascade represents a focal link between transmembrane signals of diverse origin, regulation of which directly affects hepatic tumor proliferation at multiple levels and is intrinsically linked to the increased cell HCC的有丝分裂发生特征。这是NIH-R01第一奖的目的，以“确定MAPK成分在膜，细胞质和核水平上调节细胞有丝分裂的机制”。具体而言，我们将（i）与刺激或抑制这些途径的特定药理剂结合使用G蛋白/IGF-L-MAPK信号通路的组成性活性或显性负分量。这些数据将确定C蛋白亚基和TK连接受体及其相关的第二使者在调节HCC中调节细胞质（MAPK）信号通路中的作用。 （ii）确定G蛋白/IGF-L-MAPK途径在调节正常和转化（HCC）肝细胞中调节核转录因子和细胞增殖以及存活中的作用。因为与HCC相关的死亡率是如此之高，因此破译了细胞生长和肿瘤进展的机制显然具有主要的临床意义和显着临床。因此，阐明在细胞质和核水平上控制细胞增殖的机制代表了不可切除的HCC新处理的潜在突破。