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（HCC）是最常见的胃肠道（GI）恶性肿瘤之一，也是全世界死亡的主要原因，但治疗选择有限。由于慢性肝病在炎症和损伤中的作用，因此被认为对 HCC 的发生和进展有显着影响。这些慢性肝病，包括肝炎、脂肪性肝病（酒精性和非酒精性）在我们的退伍军人中普遍存在，从而造成了巨大的经济和医疗负担。目前唯一可用于治疗 HCC 的药物是多激酶抑制剂索拉非尼，其疗效仅持续几个月。设计能够针对额外信号轴（HCC 异常）的安全有效的治疗方法对于治疗这种致命的恶性肿瘤至关重要。据报道，HCC 中多种致癌途径被激活，包括 PI3K/AKT/mTOR 和 Wnt/β-catenin 信号级联反应，目前对此很少或没有有效的治疗方法。特别重要的是 Wnt/β-连环蛋白途径，因为已报道在许多成人和儿童肝癌中存在 β-连环蛋白的致癌突变。尝试开发能够有效靶向Wnt/β-连环蛋白轴的药物一直极具挑战性，主要是因为β-连环蛋白是一种细胞内蛋白，没有任何酶活性，因此该轴目前被认为是“不可成药的”。 β-连环蛋白可以定位于各种细胞区室并介导多种细胞功能，其中一些功能是矛盾的，这一事实使情况变得更加复杂。因此，迫切需要鉴定可以调节 β-连环蛋白轴的特定上游信号通路，以开发针对该轴异常激活的 HCC 患者的靶向治疗。我们最近的研究揭示了一种由混合谱系激酶 3 (MLK​​3) 介导的新型信号通路，混合谱系激酶 3 是一种影响 β-连环蛋白介导的致癌信号传导的 MAPK 激酶 (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，这涉及到一条独立于 GSK3β 的新途径。尽管稳定了 β-连环蛋白，MLK3 仍抑制 β-连环蛋白/TCF 依赖性转录活性，并最终导致 G2/M 细胞周期停滞。基于初步结果，我们假设 MLK3 激活可以通过抑制传统的 Wnt/β-catenin 通路成功地拮抗 HCC 进展。目前的提案旨在利用体外（细胞）和体内（动物）模型验证我们的假设，同时阐明 MLK3 调节 HCC 中 β-catenin 通路的基本机制。为了实现我们的目标，提出了以下具体目标：（i）确定 MLK3 在 HCC 细胞中调节 Wnt/β-catenin 轴的作用，（ii）阐明 MLK3 诱导 HCC 细胞中 Wnt/β-catenin 轴调节的分子机制，以及（iii）确定 MLK3 在 HCC 细胞体内模型中拮抗 Wnt/β-catenin 轴的作用 肝癌。完成这些目标后，我们期望确定 MLK3 在 HCC 中拮抗 Wnt/β-catenin 轴的体内作用，并确定潜在机制，可用于将来开发靶向治疗方案。对磷酸-β-连环蛋白突变体的研究预计将提供新的机制见解，揭示这种拮抗作用是如何实现的，并确定 Wnt/β-连环蛋白轴的新调节因子。综合起来，这些信息可用于开发下一代（更有效）MLK3 激动剂，用作单一疗法或联合疗法，以专门针对 HCC 患者的 β-连环蛋白轴。