Deciphering and targeting a non-genetic driver pathway in hepatocellular carcinoma

破译和靶向肝细胞癌的非遗传驱动途径

• 批准号: 10548155
• 负责人: Narendra Wajapeyee
• 金额: $ 47.8万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-12 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10548155
• 关键词: American; American Cancer Society; BCL6 gene; BTB/POZ Domain; Biochemical; Biological Assay; Carcinoma; Cell Culture Techniques; Cell-Mediated Cytolysis; Cessation of life; Characteristics; Cirrhosis; Clinical; Data; Development; Diagnosis; Disease; Distal; Environment; Epigenetic Process; Erinaceidae; Follow-Up Studies; Genes; Genetic; Growth; Hepatic; Hepatocyte; Human; Immune system; Immunocompetent; Immunocompromised Host; Immunosuppression; Lead; Liver; Liver Fibrosis; Liver neoplasms; Malignant Epithelial Cell; Mediating; Modeling; Molecular; Mus; Names; Neoplasm Metastasis; Oncogenic; Pathway interactions; Patients; Pharmaceutical Preparations; Prevalence; Primary carcinoma of the liver cells; Probability; Property; Proteins; RNA analysis; Role; Series; Solubility; Survival Rate; T-Lymphocyte; Testing; Therapeutic; Transcription Repressor; Tumor Promotion; Tumor Suppressor Genes; Tumor Suppressor Proteins; United States; Validation; Xenograft procedure; analog; cell growth; design; effective therapy; epigenetic silencing; experimental study; follow-up; gene repression; genetic corepressor; genome-wide; growth promoting activity; humanized mouse; improved; inhibitor; innovation; knock-down; liver cancer model; mouse model; mutant; new therapeutic target; non-genetic; novel; novel strategies; novel therapeutics; patient derived xenograft model; pharmacologic; pre-clinical; rational design; small hairpin RNA; small molecule; small molecule inhibitor; subcutaneous; transcriptome; transcriptome sequencing; tumor; tumor eradication; tumor growth; tumor progression; tumorigenesis; zinc-binding protein

PROJECT SUMMARY Hepatocellular carcinoma (HCC) accounts for nearly 31,000 deaths annually in the United States alone. Factors that epigenetically silence an HCC tumor suppressor gene have the potential to promote tumorigenesis and thus may provide novel drug targets for HCC therapies. Using a genome-scale shRNA screen, we identified BCL6 as a putative and novel HCC driver gene. BCL6 is a transcriptional repressor with no previously documented role in HCC development and progression. We found that BCL6 was sufficient to transform cultured immortalized hepatocytes and promote HCC tumor growth in mouse subcutaneous xenografts. These oncogenic effects of BCL6 were dependent upon the ability of BCL6 to cause transcriptional repression because a transcriptional repression activity defective mutant of BCL6 failed to transform hepatocytes and promote tumor growth in mice. Based on our preliminary results, in this application we will establish the role of BCL6 as a driver of HCC, determine the mechanism by which BCL6 promotes tumor growth, and evaluate novel BCL6 targeting small-molecule inhibitors for HCC therapy. In Aim 1, we will establish the role of BCL6 in initiation and progression of hepatic tumorigenesis using a series of complementary mouse models that recapitulate characteristic features of HCC, including a mouse model of liver fibrosis (cirrhosis). This model recapitulates cirrhosis which is a cardinal feature of HCC. Additionally, based on our preliminary results that BCL6 inhibition in HCC cells increases their probability of getting cleared by T-cells, we will also use a mouse model with humanized immune system to study the impact of BCL6 in HCC progression in the context of a functional human immune system. In Aim 2, based upon the results of our RNA-seq and further follow up analysis, we will determine if epigenetic silencing of tumor suppressor HHIP and the zinc transporter ZIP14 by BCL6 is necessary for it to drive hepatic tumor growth. In Aim 3, we will evaluate our novel BCL6 inhibitors in pre-clinical mouse models of HCC, including HCC patient-derived xenograft (PDX) models for HCC therapeutics. In preliminary experiments, we have developed a novel small-molecule inhibitor designed to target the BTB domain of BCL6 and thereby disrupt its interaction with its co-repressors SMRT, NCOR and BCOR. We found that this novel BCL6 inhibitor L2-12019 inhibited the HCC cell growth in culture and in a human HCC xenograft-based mouse model. In Aim 3 studies, we will rationally design and evaluate new L2-12019 analogs to improve drug-like properties. The lead analog (with improved potency, selectivity, stability and solubility) will be tested with L2-12019 in pre-clinical mouse models of HCC and its efficacy will be compared with existing BCL6 inhibitors. Collectively, the results of the experiments proposed in this application will elucidate a novel non-genetic druggable pathway that promotes HCC tumor growth and progression and evaluate a new approach for treating HCC.

项目总结 仅在美国，每年就有近31,000人死于肝细胞癌。 使肝癌抑癌基因表观遗传沉默的因素有可能促进 肿瘤发生，因此可能为肝癌治疗提供新的药物靶点。使用基因组规模的shRNA 初步鉴定BCL6是一个可能的新的肝癌驱动基因。Bcl6是一种转录抑制因子，与 先前没有文献记载在肝细胞癌的发生和发展中的作用。我们发现BCL6足以 转化培养的永生化肝细胞促进小鼠皮下肝癌生长 异种移植物。Bcl6的这些致癌作用依赖于bcl6引起转录的能力。 BCL6转录抑制活性缺陷突变体未能转化为抑制 能促进小鼠肝细胞和肿瘤生长。根据我们的初步结果，在此应用程序中，我们将 确定bcl6在肝细胞癌中的驱动作用，确定bcl6促进肿瘤的机制 生长，并评估针对小分子抑制物的用于肝癌治疗的新型BCL6。在目标1中，我们将 通过一系列研究确定bcl6在肝肿瘤发生发展中的作用 概括肝癌特征的补充性小鼠模型，包括 肝纤维化(肝硬化)。这个模型概括了肝硬变，这是肝细胞癌的一个主要特征。另外， 根据我们的初步结果，BCL6在肝癌细胞中的抑制增加了它们被清除的可能性 在T细胞方面，我们还将使用人源化免疫系统的小鼠模型来研究BCL6对 在人类免疫系统功能正常的背景下，肝细胞癌进展。在目标2中，基于我们的 RNA-seq和进一步的后续分析，我们将确定是否表观遗传沉默的肿瘤抑制基因HHIP和 BCL6介导的锌转运蛋白ZIP14是驱动肝肿瘤生长所必需的。在目标3中，我们将评估 我们的新型bcl6抑制剂用于临床前小鼠肝癌模型，包括肝癌患者来源的异种移植(PDX) 肝细胞癌治疗的模型。在初步实验中，我们开发了一种新型的小分子抑制剂 被设计成以BCL6的BTB结构域为靶点从而破坏其与其共抑制物SMRT的相互作用， NCOR和BCOR。我们发现这种新型的bcl6抑制剂L2-12019对体外培养的肝癌细胞的生长有抑制作用 并在以人肝癌为基础的异种移植小鼠模型中进行研究。在目标3研究中，我们将合理设计和评估 新的L2-12019类似物，可改善类药物性能。铅类似物(具有改进的效力、选择性， 稳定性和溶解性)将用L2-12019在临床前的小鼠肝癌模型中进行测试，其疗效将是 与现有的BCL6抑制剂相比。总的来说，本申请中提出的实验结果 将阐明一种新的非遗传药物途径，促进肝癌肿瘤的生长和进展，并 评估治疗肝细胞癌的新方法。