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) 是全球癌症死亡的主要原因之一，每年导致超过 35,000 名美国人死亡。手术切除是 HCC 患者可用的最佳治疗方法，但仅对 20-40% 的确诊患者来说是可行的选择。未能开发出 HCC 的替代疗法是由于我们缺乏对细胞和分子水平上疾病病因的了解。我们实验室之前的报告已确定丝裂原激活蛋白激酶 (MAPK) 级联的成分是处理不同来源信号的焦点，包括与鸟嘌呤核苷酸调节蛋白 (C 蛋白) 偶联和酪氨酸激酶连接受体相关的信号。具体来说，我们已经证明在所分析的超过 80% 的人类 HCC 中抑制性 G 蛋白 (Gi Proteins) 的表达和功能发生了改变。此外，在人类和动物 HCC 模型中，Gi 蛋白的激活通过丝裂原激活蛋白激酶 (MAPK) 级联导致有丝分裂增强，这种效应在非转化肝细胞中未观察到。我们实验室的其他数据表明，HCC 和荷瘤动物的非致瘤、组织学正常肝组织中肝脏胰岛素样生长因子-I (IGF-1) 表达的变化。用 IGF-1 刺激 HCC 细胞会通过 MAPK 途径导致细胞有丝分裂增加，这种效应可通过抑制 Gi 蛋白信号传导而消除。基于这些观察，该提议的中心假设是 MAPK 级联代表跨膜之间的焦点联系不同来源的信号，其调节直接影响多个水平的肝肿瘤增殖，并且与 HCC 细胞有丝分裂特征增加有内在联系。 NIH-R01 一等奖的目的是“确定 MAPK 成分在膜、细胞质和核水平上调节细胞有丝分裂发生的机制”。具体来说，我们将(i)与刺激或抑制这些途径的特定药理学试剂一起过表达G蛋白/IGF-1-MAPK信号传导途径的组成型活性或显性失活成分。这些数据将确定 C 蛋白亚基和 TK 相关受体及其相关第二信使在调节 HCC 细胞质 (MAPK) 信号通路中的作用。 (ii) 确定 G 蛋白/IGF-l-MAPK 通路在正常和转化 (HCC) 肝细胞中调节核转录因子以及细胞增殖和存活的作用。由于与 HCC 相关的死亡率如此之高，因此通过以下方式破译其机制：细胞生长和肿瘤进展的发生显然具有重要的临床重要性和意义。因此，阐明细胞质和细胞核水平上控制细胞增殖的机制代表着开发不可切除性肝癌新疗法的潜在突破。