A Role for the Novel HAF-NFkappaB Axis in Driving Obesity-Associated Liver Cancer

新型 HAF-NFkappaB 轴在驱动肥胖相关肝癌中的作用

• 批准号: 10676965
• 负责人: Mei Yee Koh
• 金额: $ 42.14万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10676965
• 关键词: Address; Age; Albumins; Apoptosis; Automobile Driving; Cancer Etiology; Carcinoma; Cell Death; Cell Death Induction; Cells; Cessation of life; Complex; Cytoprotection; DNA Damage; Disease; Disease Progression; Early Diagnosis; Etiology; Fatty Liver; Female; Fibrosis; Functional disorder; Genes; Genetic Transcription; Genomic Instability; Goals; HAF deficiency; Hepatitis; Hepatocyte; Heterozygote; Human; Hypoxia; Hypoxia Pathway; In Vitro; Incidence; Infiltration; Inflammatory; Inflammatory Response; Link; Liver; Malignant Epithelial Cell; Malignant Neoplasms; Malignant neoplasm of liver; Measures; Mediating; Mediator; Medical; Metabolic; Molecular; Monitor; Mus; Neoplastic liver; Nuclear; Obesity; Obesity Epidemic; Outcome; Pathogenesis; Pathway interactions; Patient-Focused Outcomes; Patients; Phosphorylation; Phosphotransferases; Physiological; Play; Prevalence; Primary Malignant Neoplasm of Liver; Primary carcinoma of the liver cells; Prognostic Marker; Proteins; Role; Sampling; Severities; Signal Transduction; Small Interfering RNA; Stress; TNF gene; TNFRSF5 gene; Testing; Time; Tissues; Transfection; Transforming Growth Factor beta; Tumor Necrosis Factor-Beta; Tumor Suppressor Proteins; Viral hepatitis; cytokine; diagnostic strategy; dietary; effective therapy; fatty liver disease; in vivo; insight; knock-down; liver inflammation; liver injury; male; metabolic-associated fatty liver disease; mortality; mouse model; neoplastic; new therapeutic target; nonalcoholic steatohepatitis; novel; novel diagnostics; novel therapeutic intervention; overexpression; p65; potential biomarker; predictive marker; prevent; response; screening; therapeutic target; therapy resistant; treatment response; treatment strategy; ubiquitin-protein ligase

Hepatocellular carcinoma (HCC), the predominant primary cancer of the liver, is 4th leading cause of cancer deaths, and the fastest growing malignancy in the US. Advanced-stage HCC remains largely incurable due to a dismal response rate (<20%) and therapeutic resistance. The current obesity epidemic has been associated with the rising prevalence of metabolic (dysfunction) associated fatty liver disease (MAFLD) and its inflammatory component, non-alcoholic steatohepatitis (NASH), which can lead to HCC. MAFLD-HCC incidence is increasing dramatically, underscoring an unmet medical need for new diagnostic and treatment strategies. Here, we describe a novel tumor suppressor role of the Hypoxia-Associated Factor, HAF, in MAFLD-HCC. Both global haploinsufficiency and hepatocyte-specific deletion of HAF in mice result in HCC with hallmarks of NASH including severe steatosis with hepatocyte degeneration (hepatocyte ballooning), fibrosis, and increased inflammatory cell infiltration. HAF loss in both mouse models or by siRNA transfection in HCC cells is associated with decreased activation of the p65/p50 NF-κB transcriptional subunits, and in decreased levels of their upstream regulators, TAK1 and NEMO. Endogenous HAF forms a complex with NEMO and TAK1, suggesting that HAF modulates the NF-κB pathway by directly modulating the stability of these proteins, potentially through HAF’s E3 ubiquitin ligase activity. HAF knockdown was associated with increased spontaneous apoptosis, whereas HAF overexpression protected cells against TNF-induced cell death, suggesting that HAF may play a tumor suppressor role by protecting cells against death associated with liver inflammation (hepatitis) that can lead to HCC. Indeed, HAF levels are suppressed by conditions prevalent during hepatitis such as hypoxia and elevated TNF or TGF-β, whereas HAF are increased by DNA damage, suggesting that HAF may contribute to NF-κB activation in response to genomic instability in pre-neoplastic hepatocytes. Significantly, HAF was highly expressed in most cases of human hepatitis but was undetectable in 94% of human HCCs examined (65 cases). Thus, our hypothesis is that HAF plays a novel tumor suppressor role in HCC by facilitating NF-κB activation that promotes the survival of hepatocytes during hepatitis. Suppression of HAF by hypoxia or inflammatory cytokines during hepatitis results in increased cellular turnover that drives progression to NASH and HCC. Our overall goal is to identify new predictive/prognostic biomarkers or therapeutic targets for HCC, particularly those relevant to MAFLD-HCC. In Aim 1, we will test the hypothesis that HAF activates the NF-κB pathway by modulating the stability of TAK1 and NEMO, and thus identify the molecular mechanisms regulating the HAF- NF-κB axis. In Aim 2, we will test the hypothesis that HAF protects cells from excessive cell death during hepatitis, thus preventing progression to NASH and HCC. In Aim 3, we will test the hypothesis that HAF deregulation is associated with progression to HCC by investigating HAF expression in > 500 patient samples, to determine the association of HAF and its downstream targets to HCC initiation and progression or to treatment response.

肝细胞癌 (HCC) 是肝脏的主要原发性癌症，是第四大癌症原因 死亡人数，以及美国增长最快的恶性肿瘤。由于以下原因，晚期 HCC 在很大程度上仍然无法治愈 反应率低（<20%）和治疗抵抗。当前的肥胖流行与以下因素有关： 代谢（功能障碍）相关脂肪肝病（MAFLD）及其炎症的患病率不断上升 非酒精性脂肪性肝炎 (NASH)，可导致 HCC。 MAFLD-HCC 发病率正在增加 引人注目的是，突显了对新的诊断和治疗策略的医疗需求尚未得到满足。在这里，我们 描述了缺氧相关因子 HAF 在 MAFLD-HCC 中的新型肿瘤抑制作用。两者都是全球性的 小鼠中 HAF 的单倍体不足和肝细胞特异性缺失导致具有 NASH 特征的 HCC 包括严重脂肪变性伴肝细胞变性（肝细胞气球样变）、纤维化和肝细胞增多 炎症细胞浸润。两种小鼠模型中的 HAF 损失或 HCC 细胞中的 siRNA 转染均与 HAF 损失相关 p65/p50 NF-κB 转录亚基的激活减少，及其水平降低 上游调节器 TAK1 和 NEMO。内源性 HAF 与 NEMO 和 TAK1 形成复合物，表明 HAF 通过直接调节这些蛋白质的稳定性来调节 NF-κB 通路，可能通过 HAF 的 E3 泛素连接酶活性。 HAF 敲低与自发性细胞凋亡增加相关， 而 HAF 过表达可保护细胞免受 TNF 诱导的细胞死亡，这表明 HAF 可能发挥了重要作用 通过保护细胞免受与肝脏炎症（肝炎）相关的死亡来发挥肿瘤抑制作用 导致肝癌。事实上，HAF 水平会受到肝炎期间常见的情况（例如缺氧和 TNF 或 TGF-β 升高，而 HAF 因 DNA 损伤而升高，表明 HAF 可能有助于 NF-κB 激活响应肿瘤前肝细胞中的基因组不稳定性。值得注意的是，HAF 高度 在大多数人类肝炎病例中表达，但在所检查的 94% 的人类 HCC 中（65 例）检测不到。 因此，我们的假设是 HAF 通过促进 NF-κB 激活在 HCC 中发挥新的肿瘤抑制作用 促进肝炎期间肝细胞的存活。缺氧或炎症抑制 HAF 肝炎期间的细胞因子导致细胞更新增加，从而推动 NASH 和 HCC 的进展。我们的 总体目标是确定 HCC 新的预测/预后生物标志物或治疗靶点，特别是那些 与 MAFLD-HCC 相关。在目标 1 中，我们将通过以下方式检验 HAF 激活 NF-κB 通路的假设： 调节 TAK1 和 NEMO 的稳定性，从而确定调节 HAF-的分子机制 NF-κB 轴。在目标 2 中，我们将检验 HAF 在肝炎期间保护细胞免遭过度细胞死亡的假设， 从而防止进展为 NASH 和 HCC。在目标 3 中，我们将检验 HAF 放松管制的假设 通过调查> 500个患者样本中的HAF表达，以确定与HCC进展相关的 HAF 及其下游靶点与 HCC 发生和进展或治疗反应的关联。