Targeting beta-catenin in liver pathology: Novel Interactions, Novel Paradigms

靶向肝脏病理学中的 β-连环蛋白：新的相互作用，新的范式

基本信息

批准号：
8870348
负责人：
Satdarshan Singh Monga
金额：
$ 32.85万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-07-01 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8870348
关键词：
Accounting Address Adherens Junction Adverse effects Affect Anabolism Antioxidants Ascorbic Acid Biological Biological Assay Biological Process Biology CTNNB1 gene Cell Adhesion Cell Proliferation Cell-Cell Adhesion Cyclic AMP-Dependent Protein Kinases Death Rate Development Diethylnitrosamine Down-Regulation Equilibrium Event Exons Exposure to Felis catus Generations Grant Growth Health Hepatic Hepatoblastoma Hepatocarcinogenesis Hepatocyte Human In Vitro Incidence Injury Investigation Knockout Mice Lead Liver Liver Fibrosis Malignant Neoplasms Metabolic syndrome Metabolism Molecular Morphologic artifacts Mus Natural regeneration Outcome Oxidative Stress PTPN11 gene Pathology Pathway interactions Patient Selection Phosphorylation Primary carcinoma of the liver cells Primates Process Proteins Regulation Reporting Research Proposals Rodent Role Serine Serine/Threonine Phosphorylation Serum Signal Pathway Signal Transduction Site Somatic Mutation Testing Threonine Up-Regulation Ursidae Family arm ascorbate base beta catenin cancer cell cancer therapy chemical carcinogen dietary supplements hepatoma cell in vivo liver injury novel personalized medicine prevent research study therapeutic target therapy resistant tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Wnt/ß-catenin signaling is pertinent in liver biology in regulating zonation, regeneration, development and metabolism. However aberrations in this pathway have been reported in hepatic fibrosis, hepatic injury, hepatoblastomas and hepatocellular cancer (HCC). Targeting ß-catenin in HCC is imminent. It is the 3rd fatal cancer worldwide and its incidence and associated death rates have steadily increased since the 1980s. Cellular & molecular basis of HCC is poorly understood. Wnt signaling has been deemed active in 17-40% of HCCs due to various reasons and around 20-40% of all HCCs harbor monoallelic somatic mutations in the exon-3 of the ß-catenin gene (CTNNB1) that encodes for a non-serine/threonine phosphorylatable, stable and constitutively active protein, making it an attractive therapeutic target. We have made several important and some paradoxical observations over the last few years including identification of novel interactions and cross-regulations between ß-catenin and other molecules. These may have significant biological and translational implications mandating an in-depth analysis that may have widespread implications in not just HCC but other hepatic pathologies where ß-catenin targeting may be of essence such as hepatic fibrosis, injury and metabolic syndrome. The overarching hypothesis of the proposal is that therapeutic targeting of ß-catenin must take into account existing redundancies and crosstalk with specific signaling pathways, which need to be comprehensively elucidated. We will test these hypotheses in three distinct but thematically related aims. In aim 1, we will investigate the mechanism of oxidative stress dependent enhanced hepatocarcinogenesis in ß-catenin conditional knockout mice (Hep-ß-Cat KO) to address if enhanced HCC is a murine 'artifact' due to the role of ß-catenin in vitamin C biosynthesis in murine hepatocytes. We identified a novel role of ß-catenin signaling in vitamin C biosynthesis in the murine liver, whic is a known major antioxidant. Unlike humans and primates, rodents synthesize vitamin C in the hepatocytes and regular mouse chow is devoid of ascorbic acid. We hypothesize that increased HCC and oxidative stress in Hep-ß-Cat KO is due to compromised vitamin C biosynthesis and its normalization will alleviate HCC and demonstrate ß-catenin to be a global therapeutic target in HCC. In aim 2 we will investigate mechanism and biological implications of PDGFRα upregulation and activation after ß-catenin inhibition in HCC cells. We hypothesize that PDGFRα upregulation along with the activation of its specific downstream signaling arm is an important mechanism that will allow growth of HCC after ß-catenin inhibition and that understanding the role and regulation of this phenomena will bear significantly on efficacious HCC treatment. In aim 3, we will investigate the role and regulation of ?-catenin stabilization following inhibition of ß-catenin expression in the liver. We hypothesize that ?-catenin stabilization during ß-catenin inhibition in HCC will prevent any untoward effect related to disruption of cell-cell adhesion. All the proposed studies in the grant will utilize a balance of i vitro and in vivo set of experiments and the expected outcomes will be highly relevant and translational.

描述（由申请人提供）：Wnt/ß-连环蛋白信号传导在肝脏生物学中与调节分区、再生、发育和代谢相关，然而，该途径的异常在肝纤维化、肝损伤、肝母细胞瘤和肝细胞癌（HCC）中已有报道。针对 HCC 的靶向治疗迫在眉睫，它已成为全球第三大癌症，自 2017 年以来其发病率和相关致命死亡率不断增加。 20 世纪 80 年代，人们对 HCC 的细胞和分子基础知之甚少，由于各种原因，Wnt 信号传导在 17-40% 的 HCC 中被认为是活跃的，并且大约 20-40% 的 HCC 在 ß 外显子 3 中存在单等位基因体细胞突变。 -连环蛋白基因 (CTNNB1)，编码非丝氨酸/苏氨酸可磷酸化、稳定且具有组成型活性的蛋白质，使其成为在过去的几年里，我们进行了一些重要且有些矛盾的观察，包括鉴定出β-连环蛋白和其他分子之间的新相互作用和交叉调节，这些可能具有重要的生物学和翻译意义，需要进行深入分析。可能不仅对 HCC 具有广泛的影响，而且对β-连环蛋白靶向可能至关重要的其他肝脏病理学也有广泛的影响，例如肝纤维化、损伤和代谢综合征。该提案的首要假设是治疗靶向。 ß-连环蛋白必须考虑到现有的冗余和与特定信号通路的串扰，这需要全面阐明。在目标 1 中，我们将研究氧化应激依赖性增强的机制。 β-连环蛋白条件敲除小鼠的肝癌发生 (Hep-ß-Cat KO) 来解决增强型 HCC 是否是小鼠“人为因素”，因为 ß-catenin 在小鼠肝细胞维生素 C 生物合成中的作用。我们发现了 ß-catenin 信号在维生素 C 生物合成中的新作用。小鼠肝脏是一种已知的主要抗氧化剂，与人类和灵长类动物不同，啮齿类动物在肝细胞中合成维生素 C，而普通小鼠食物中缺乏维生素 C。我们认为 Hep-ß-Cat KO 中 HCC 和氧化应激的增加是由于维生素 C 生物合成受损，其正常化将减轻 HCC 并证明 ß-catenin 是 HCC 的全球治疗靶点。研究 HCC 细胞中 ß-catenin 抑制后 PDGFRα 上调和激活的机制和生物学意义，我们捕获了 PDGFRα 上调及其特定下游信号臂的激活。是β-连环蛋白抑制后允许 HCC 生长的重要机制，了解这种现象的作用和调节将对有效的 HCC 治疗产生重大影响。在目标 3 中，我们将研究 β-连环蛋白稳定后的作用和调节。 β-连环蛋白在肝脏中的表达的抑制我们追求在 HCC 中 β-连环蛋白抑制过程中 β-连环蛋白的稳定将防止与细胞-细胞粘附破坏相关的任何不良影响。该赠款中的研究将利用体外和体内实验组的平衡，预期结果将具有高度相关性和转化性。