Elucidation of MLK3 Signaling in Hepatocellular Carcinoma

肝细胞癌中 MLK3 信号传导的阐明

• 批准号: 10038787
• 负责人: BASABI RANA
• 金额: --
• 依托单位: JESSE BROWN VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10038787
• 关键词: Adenomatous Polyposis Coli; Adenomatous Polyposis Coli Protein; Adult; Agonist; Alcoholism; Animals; BAY 54-9085; Cause of Death; Cell Cycle Arrest; Cell physiology; Ceramides; Childhood Liver Cancer; Combined Modality Therapy; Complex; Cyclin D1; Development; Diabetes Mellitus; Disease; Etiology; Event; FRAP1 gene; Family; Fatty Liver; Financial Hardship; Future; Genes; Genetic Diseases; Genetic Transcription; Goals; Hepatitis; Hepatitis B Virus; Hepatitis C virus; Human; In Vitro; Inflammation; Injury; Link; Liver Cirrhosis; Liver neoplasms; M cell; Malignant Epithelial Cell; Malignant Neoplasms; Malignant neoplasm of gastrointestinal tract; Mediating; Mediator of activation protein; Medical; Mitogen-Activated Protein Kinase Kinases; Modeling; Molecular; Mus; Mutation; Nuclear Translocation; Obesity; Oncogenic; PI3K/AKT; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphotransferases; Population; Primary carcinoma of the liver cells; Proteins; Proto-Oncogene Proteins c-akt; Regulation; Reporting; Role; Signal Pathway; Signal Transduction; Signaling Protein; TCF Transcription Factor; Testing; Therapeutic; Tumor Suppressor Proteins; Veterans; Viral hepatitis; WNT Signaling Pathway; base; beta catenin; c-myc Genes; cancer cell; chronic liver disease; design; effective therapy; glycogen synthase kinase 3 beta; in vivo; in vivo Model; inhibitor/antagonist; insight; mixed lineage kinase 3; mutant; nanoparticle; new therapeutic target; next generation; non-alcoholic; nonalcoholic steatohepatitis; novel; overexpression; problem drinker; public health relevance; survivin; targeted treatment; therapy resistant; transcription factor

 DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC) is one of the most common gastrointestinal (GI) malignancies and a major cause of death worldwide, with limited therapeutic options. Chronic liver diseases are believed to contribute significantly towards the development and progression of HCC due to their role in inflammation and injury. These chronic liver diseases including hepatitis, fatty live diseases (alcoholic and nonalcoholic) are prevalent among our veterans, thus creating a significant financial and medical burden. The only drug currently available to treat HCC is the multikinase inhibitor Sorafenib, which is effective only for a few months. Designing safe and efficient therapeutic approaches that can target additional signaling axes (aberrant in HCC) is critical for treating this deadly form of malignancy. Activation of various oncogenic pathways have been reported in HCC, which include PI3K/AKT/mTOR and Wnt/β-catenin signaling cascades, for which little or no effective therapies are available currently. Of particular importance is the Wnt/β-catenin pathway, since oncogenic mutations of β- catenin have been reported in a number of adult and childhood liver cancers. Attempts to develop drugs that can effectively target the Wnt/β-catenin axis has been extremely challenging mostly due to the fact that β- catenin is an intracellular protein without any enzymatic activity, and thus this axis is currently considered "undruggable". This is further complicated by the fact that β-catenin can localize in various cellular compartments and mediate multiple cellular functions some of which are paradoxical. Identification of specific upstream signaling pathways that can modulate β-catenin axis is thus critically needed to develop targeted therapies for HCC patients with aberrant activation of this axis. Our recent studies revealed a novel signaling pathway mediated by Mixed Lineage Kinase 3 (MLK3), a MAPK Kinase Kinase (MAP3K) that impacts β- catenin-mediated oncogenic signaling. Our studies indicate that MLK3 can phosphorylate and stabilize β- catenin in cancer cells, which involves a novel pathway independent of GSK3β. Despite stabilizing β-catenin, MLK3 inhibited β-catenin/TCF-dependent transcriptional activity and ultimately resulted in G2/M cell cycle arrest. Based on the preliminary results, we hypothesize that MLK3 activation can successfully antagonize HCC progression via inhibiting conventional Wnt/β-catenin pathway. The current proposal aims to validate our hypothesis utilizing both in vitro (cellular) and in vivo (animal) models while elucidating the fundamental mechanisms by which MLK3 modulates β-catenin pathway in HCC. The following specific aims are proposed to achieve our goals: (i) Determine the role of MLK3 in modulating Wnt/β-catenin axis in HCC cells, (ii) Elucidate the molecular mechanism of MLK3-induced modulation of Wnt/β-catenin axis in HCC cells and (iii) Determine the role of MLK3 in antagonizing Wnt/β-catenin axis in an in vivo model of HCC. Upon completion of these aims, we expect to establish the in vivo role of MLK3 in antagonizing Wnt/β-catenin axis in HCC, and identify the potential mechanism, which can be utilized for developing targeted therapeutic options in the future. The studies with the phospho-β-catenin mutants are expected to provide novel mechanistic insight revealing how this antagonism is achieved and identify new regulators of Wnt/β-catenin axis. Combined together, this information can be utilized to develop the next generation (more potent) MLK3 agonists to be utilized as monotherapy or in combination therapies to specifically target the β-catenin axis i HCC patients.

 描述(由申请人提供)： 肝细胞癌是最常见的胃肠道恶性肿瘤之一，也是世界范围内的主要死亡原因，治疗方法有限。慢性肝病由于其在炎症和损伤中的作用，被认为对肝细胞癌的发生和发展有重要贡献。这些慢性肝病包括肝炎、脂肪肝(酒精性和非酒精性)在我们的退伍军人中很普遍，因此造成了巨大的经济和医疗负担。目前唯一可用于治疗肝癌的药物是多激酶抑制剂索拉非尼，它的有效时间仅为几个月。设计安全有效的治疗方法，可以针对额外的信号轴(肝癌中的异常)，对于治疗这种致命的恶性肿瘤是至关重要的。多种致癌途径的激活在肝细胞癌中已有报道，其中包括PI3K/Akt/mTor和Wnt/β-catenin信号转导通路，但目前几乎没有有效的治疗方法。尤其重要的是Wnt/β-连环蛋白途径，因为已有报道在许多成人和儿童肝癌中发现了β-连环蛋白的致癌突变。试图开发有效靶向Wnt/β-连环蛋白轴的药物一直具有极大的挑战性，主要是因为β-连环蛋白是一种细胞内蛋白质，没有任何酶活性，因此该轴目前被认为是“不可用药的”。更复杂的是，β-连环蛋白可以定位于不同的细胞室，并调节多种细胞功能，其中一些功能是矛盾的。因此，识别可以调节β-连环蛋白轴的特定上游信号通路是开发针对该轴异常激活的肝癌患者的靶向治疗的关键。我们最近的研究揭示了一种新的信号通路，该信号通路由MAPK3介导，它是一种影响β-连环蛋白介导的致癌信号的MAP3K。我们的研究表明，MLK3可以磷酸化和稳定癌细胞中的β-连环蛋白，这涉及到一条不依赖于β的新途径。尽管MLK3稳定了β-连环蛋白，但它抑制了β-连环蛋白/Tcf依赖的转录活性，最终导致G2/M期细胞周期停滞。根据初步结果，我们推测MLK3的激活可以通过抑制传统的Wnt/β-catenin通路而成功地拮抗肝癌的进展。目前的建议旨在利用体外(细胞)和体内(动物)模型来验证我们的假设，同时阐明MLK3在肝癌中调节β-连环蛋白途径的基本机制。为了实现我们的目标，我们提出了以下具体目标：(I)确定MLK3在调节肝癌细胞Wnt/β-catenin轴中的作用；(Ii)阐明MLK3调节肝癌细胞中Wnt/β-catenin轴的分子机制；(Iii)在肝癌体内模型中确定MLK3在拮抗Wnt/β-catenin轴中的作用。在完成这些目标后，我们期望建立MLK3在肝癌中拮抗Wnt/β-catenin轴的体内作用，并确定其潜在的机制，为未来开发靶向治疗方案提供依据。对磷酸化β-连环蛋白突变体的研究有望提供新的机制洞察力，揭示这种拮抗作用是如何实现的，并发现新的Wnt/β-连环蛋白轴调节因子。结合起来，这些信息可以用来开发下一代(更有效的)MLK3激动剂，作为单一疗法或联合疗法，专门针对β-连环蛋白轴I肝细胞癌患者。