Elucidation of MLK3 Signaling in Hepatocellular Carcinoma

肝细胞癌中 MLK3 信号传导的阐明

• 批准号: 9032316
• 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 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9032316
• 关键词: Adenomatous Polyposis Coli; Adult; Agonist; Alcoholism; American Society of Hematology; Animal Model; 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; Event; FRAP1 gene; Family; Fatty Liver; Figs - dietary; Future; Gene Targeting; Genes; Genetic Transcription; Goals; Hepatitis; Hepatitis B Virus; Hepatitis C virus; Hereditary Disease; Human; In Vitro; Inflammation; Injury; Life; 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; 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; 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; interest; 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，也是全球范围内的主要死亡原因，治疗选择有限。由于慢性肝病在炎症和损伤中的作用，慢性肝病被认为对HCC的发展和进展有显着贡献。这些慢性肝病，包括肝炎，脂肪肝疾病（酒精性和非酒精性）在我们的退伍军人中很普遍，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，其有效期仅为几个月。设计安全有效的治疗方法，可以靶向额外的信号轴（HCC中的异常），对于治疗这种致命的恶性肿瘤至关重要。在HCC中已经报道了多种致癌通路的激活，包括PI 3 K/AKT/mTOR和Wnt/β-catenin信号级联，目前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，因为在许多成人和儿童肝癌中已经报道了β-连环蛋白的致癌突变。开发能够有效靶向Wnt/β-连环蛋白轴的药物的尝试一直极具挑战性，这主要是由于β-连环蛋白是没有任何酶活性的细胞内蛋白质的事实，因此该轴目前被认为是“不可用药的”。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，其中一些是自相矛盾的，这一事实使情况进一步复杂化。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）介导的新的信号通路，MLK 3是一种影响β-连环蛋白介导的致癌信号的MAPK激酶激酶（MAP 3 K）。我们的研究表明，MLK 3可以磷酸化和稳定癌细胞中的β- catenin，这涉及一个新的途径，不依赖于GSK 3 β。尽管稳定了β-catenin，MLK 3抑制了β-catenin/TCF依赖的转录活性，并最终导致G2/M细胞周期停滞。基于初步结果，我们假设MLK 3激活可以通过抑制常规Wnt/β-catenin途径成功地拮抗HCC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MLK 3调节HCC中β-catenin通路的基本机制。提出以下具体目标以实现我们的目标：（i）确定MLK 3在HCC细胞中调节Wnt/β-连环蛋白轴的作用，（ii）阐明MLK 3诱导HCC细胞中Wnt/β-连环蛋白轴调节的分子机制，以及（iii）确定MLK 3在HCC体内模型中拮抗Wnt/β-连环蛋白轴的作用。在完成这些目标后，我们期望建立MLK 3在HCC中拮抗Wnt/β-catenin轴的体内作用，并确定潜在的机制，这可以用于未来开发靶向治疗方案。对磷酸-β-连环蛋白突变体的研究有望提供新的机制见解，揭示这种拮抗作用是如何实现的，并鉴定Wnt/β-连环蛋白轴的新调节剂。结合在一起，该信息可用于开发下一代（更有效的）MLK 3激动剂，其用作单一疗法或组合疗法以特异性靶向HCC患者中的β-连环蛋白轴。