A Novel Druggable Epigenetic Vulnerability Pathway in HCC

HCC 中一种新的可药物化表观遗传脆弱性途径

• 批准号: 10374806
• 负责人: MICHELLE ALICE KELLIHER
• 金额: $ 56.93万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10374806
• 关键词: American; American Cancer Society; Arginine; Attenuated; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Characteristics; Cirrhosis; Clinical; Development; Diagnosis; Disease; Drug Targeting; Environment; Epigenetic Process; Erinaceidae; Fibroblasts; Genetic Heterogeneity; Growth; Hepatic; Hepatocyte; Human; Immune system; Immunocompetent; Immunocompromised Host; Liver Fibrosis; Liver neoplasms; Malignant Epithelial Cell; Malignant Neoplasms; Mediating; Modeling; Molecular; Mus; Natural Killer Cells; Oncogenic; Pathway interactions; Patients; Pharmacology; Phosphotransferases; Prevalence; Primary carcinoma of the liver cells; Protein Kinase; Proteins; RNA Splicing; RNA interference screen; Role; SHH gene; Sampling; Series; Serine; Specificity; Testing; Therapeutic; Tumor Suppressor Genes; Tumor Suppressor Proteins; United States; Xenograft procedure; base; clinically relevant; effective therapy; epigenetic silencing; experimental study; genome-wide; innovation; liver cancer model; mRNA Precursor; mouse model; neoplastic cell; new therapeutic target; novel; novel strategies; novel therapeutics; overexpression; patient derived xenograft model; small molecule inhibitor; smoothened signaling pathway; subcutaneous; tumor; tumor eradication; tumor growth; tumorigenesis

PROJECT SUMMARY Hepatocellular carcinoma (HCC) accounts for nearly 29,000 deaths annually in the United States alone. However, the molecular mechanisms that drive HCC development remain elusive and current HCC therapies provide negligible clinical benefit. 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. T o discover such factors, we performed an innovative genome-wide human RNA interference (RNAi) screen to identify factors that mediate epigenetic silencing of the HCC tumor suppressor gene Hedgehog-Interacting Protein (HHIP). HHIP is a negative regulator of Sonic hedgehog (SHH) signaling and loss of HHIP due to epigenetic silencing aberrantly activates SHH signaling, which has been proposed to promote tumor growth in multiple cancers including HCC. One of the factors identified in our screen is CDC-like kinase 1 (CLK1), a dual specificity protein kinase that phosphorylates serine/arginine-rich proteins involved in pre-mRNA splicing. We found that CLK1 transforms cultured immortalized hepatocytes and promotes HCC tumor growth in mouse subcutaneous xenografts, and these effects are dependent upon CLK1 protein kinase activity. Notably, epigenetic silencing of HHIP and CLK1 overexpression occur frequently in HCC patient samples, supporting the clinical relevance of our results. Based on these collective findings, we hypothesize that CLK1 is a driver of HCC and functions by epigenetically silencing the tumor suppressor HHIP. The results of the experiments proposed in this application will establish the role of CLK1 as a driver of HCC, determine the mechanism by which CLK1 promotes tumor growth, and evaluate CLK1 as a drug target for HCC therapy. In Aim 1, we will establish the role of CLK1 in initiation and progression of hepatic tumorigenesis using a series of complementary mouse models that recapitulate characteristic features of HCC. In Aim 2, we will test our hypothesis that CLK1 promotes hepatic tumor growth through epigenetic silencing of HHIP, resulting in aberrant activation of SHH signaling. We will also investigate other mechanisms by which CLK1 may promote tumor growth. In Aim 3, we will evaluate CLK1 as a novel drug target for the development of HCC therapeutics. In preliminary experiments, we have found that inhibition of CLK1 enhances natural killer (NK) cell-mediated eradication of HCC cells. Therefore, we predict that reactivation of HHIP by pharmacological inhibition of CLK1 will: (1) directly inhibit tumor growth by blocking oncogenic SHH signaling, and (2) augment NK cell-mediated eradication of tumor cells. To test these predictions we will determine whether the highly specific CLK1 small molecule inhibitor KH-CB19 can effectively inhibit growth of hepatic tumors and enhance the ability of NK cells to eradicate tumors using a complementary series of immunocompromised and immunocompetent mouse models of HCC. Collectively, the results of the experiments proposed in this application will elucidate a novel druggable pathway that promotes HCC development and evaluate a new approach for treating HCC.

项目总结 仅在美国，每年就有近29,000人死于肝细胞癌。 然而，推动肝细胞癌发展的分子机制仍然难以捉摸，目前的肝细胞癌治疗方法 提供的临床益处微不足道。使肝癌肿瘤抑制基因表观遗传沉默的因素有 有促进肿瘤发生的潜力，因此可能为肝癌治疗提供新的药物靶点。去发现 这些因素，我们进行了创新的全基因组人类RNA干扰(RNAi)筛查以确定 肝癌抑癌基因Hedgehog相互作用蛋白表观遗传沉默的介导性因素 (臀部)。HHIP是Sonic Hedgehog(SHH)信号的负调节因子，表观遗传导致HHIP丢失 沉默异常地激活SHH信号，这已被认为促进多发性骨髓瘤的生长 包括肝癌在内的癌症。在我们的屏幕上发现的因素之一是CDC样激酶1(CLK1)，一种双重的 特异性蛋白激酶，磷酸化参与前-mRNA剪接的富含丝氨酸/精氨酸的蛋白。我们 发现CLK1可转化培养的永生化肝细胞并促进小鼠肝癌肿瘤的生长 皮下异种移植，这些作用依赖于CLK1蛋白激酶活性。值得注意的是， HHIP和CLK1过度表达的表观遗传沉默在肝细胞癌患者样本中频繁发生，支持 我们研究结果的临床相关性。根据这些集体发现，我们假设CLK1是 肝细胞癌和通过表观遗传学沉默肿瘤抑制因子HHIP发挥作用。实验的结果 本申请中提出的将确立CLK1作为肝细胞癌的驱动因素的作用，通过以下方式确定机制 其中CLK1促进肿瘤生长，并评价CLK1作为治疗肝癌的药物靶点。在目标1中，我们将 通过一系列的研究来确定CLK1在肝肿瘤发生发展中的作用 补充小鼠模型，概括肝细胞癌的特征。在目标2中，我们将测试我们的 假设CLK1通过表观遗传沉默HHIP促进肝肿瘤生长，导致 SHH信号的异常激活。我们还将研究CLK1可能通过的其他机制来促进 肿瘤生长。在目标3中，我们将评估CLK1作为开发肝癌治疗的新药靶点。 在初步实验中，我们发现抑制CLK1增强了自然杀伤(NK)细胞介导的 根除肝癌细胞。因此，我们预测通过对CLK1的药理抑制来重新激活HHIP 将：(1)通过阻断致癌的SHH信号直接抑制肿瘤生长；(2)增强NK细胞介导的 消灭肿瘤细胞。为了测试这些预测，我们将确定高度特异的CLK1小分子 分子抑制剂KH-CB19能有效抑制肝肿瘤的生长，增强NK细胞的功能 使用一系列互补的免疫受损和免疫活性小鼠来根除肿瘤 肝细胞癌模型。总而言之，本申请中提出的实验结果将阐明一种新的 促进肝癌发展的可用药途径，并评估治疗肝癌的新方法。