Exploration of ZHX2 as a novel substrate of pVHL and an oncogenic driver of renal cancer

探索 ZHX2 作为 pVHL 的新型底物和肾癌的致癌驱动因素

• 批准号: 9768410
• 负责人: Qing Zhang
• 金额: $ 5.73万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2019-09-02
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9768410
• 关键词: Accounting; Adaptor Signaling Protein; Address; Agar; Automobile Driving; Binding; CCL2 gene; Cancer Patient; Cancer cell line; Cell Proliferation; Cells; ChIP-seq; Chronic; Clear cell renal cell carcinoma; Conventional (Clear Cell) Renal Cell Carcinoma; Coupled; Cytotoxic Chemotherapy; Data; Development; Disease; Event; Foundations; Gene Expression; Gene Targeting; Genes; Genomics; Growth; Homeodomain Proteins; Hydroxylation; Hypermethylation; Hypoxia; Hypoxia Inducible Factor; IL8 gene; In Vitro; Kidney; Kidney Neoplasms; Literature; Lymphoma; Malignant Neoplasms; Mediating; Mixed Function Oxygenases; Molecular; Mutation; NF-Kappa B p65; NF-kappa B; Nuclear; Oncogenes; Oncogenic; Oncoproteins; Pathway interactions; Patients; Phenotype; Primary carcinoma of the liver cells; Process; Procollagen-Proline Dioxygenase; Proline; Proteins; Regulation; Renal Cell Carcinoma; Renal carcinoma; Reporting; Resistance; Role; Signal Pathway; Signal Transduction; Site; Specimen; Transcription Repressor/Corepressor; Tumor Suppressor Genes; Tumor Suppressor Proteins; Tumor Tissue; Ubiquitination; Up-Regulation; Zinc Fingers; cancer therapy; genetic signature; genome-wide; inhibitor/antagonist; innovation; insight; knock-down; lipid metabolism; mouse model; novel; novel therapeutic intervention; novel therapeutics; outcome forecast; p65; prognostic value; promoter; screening; transcription factor; tumor; tumor growth; tumor xenograft; tumorigenesis; ubiquitin-protein ligase

Project Summary Clear cell renal cell carcinoma (ccRCC), which accounts for approximately 85% of all renal cancers, is resistant to a variety of cancer therapies and is highly lethal. A hallmark of ccRCC is the inactivation of the von Hippel Lindau (VHL) tumor suppressor gene, which is inactivated either by mutation or hypermethylation in up to 90% of ccRCC. While pVHL functions as an E3 ubiquitin ligase adaptor protein that promotes the degradation of hypoxia inducible (HIFα) transcription factors, other key pVHL substrates are only now emerging and their functional roles in renal cancer remains undefined. Here we identify a zinc-finger/homeodomain protein ZHX2 as a potential novel pVHL substrate by using a newly developed genome-wide in vitro expression strategy coupled with GST-binding screening. Our preliminary data suggests that pVHL interacts with and degrades ZHX2 in a hydroxylase activity-dependent manner, similar to regulation of the HIFα proteins. Functionally, knockdown of ZHX2 blocks cell proliferation, soft agar growth and xenograft tumor growth of pVHL-deficient renal cancer cells. Importantly, ZHX2 expression levels are strongly elevated in ccRCC tumors compared to normal patients. Mechanistically, ZHX2 interacts with the RelA/p65 subunit of NF-kB and positively regulates pVHL-loss induced RelA/p65 nuclear localization. Integrated analyses of ChIP-Seq and microarray also reveal that ZHX2 regulates both NF-kB-dependent and independent pathways in ccRCC. Therefore, we hypothesize that ZHX2 promotes renal oncogenesis through both NF-kB dependent and independent pathways following VHL inactivation. This is the first study directed at a pro-oncogenic function for ZHX2, with the focus on its key role downstream of the loss of pVHL in renal cancer. In Specific Aim 1, we will study the mechanism by which ZHX2 is regulated by pVHL in a hydroxylation-dependent manner. In Specific Aim 2, we will determine the functional significance of deregulated ZHX2 in pVHL-deficient renal cancer. In Specific Aim 3, we will determine the mechanisms by which ZHX2 regulates NF-kB-dependent and -independent signaling and renal tumorigenesis upon pVHL loss. Successful completion of this proposal would provide significant new molecular insight into oncogenic mechanisms associated with the great majority of ccRCC as well as the potential for new therapies for this typically lethal disease.

项目摘要 占所有肾癌的85％的透明细胞肾细胞癌（CCRCC）具有抗性 进行多种癌症疗法，高度致命。 CCRC的标志是冯·希珀（Von Hippel）的失活 lindau（VHL）肿瘤抑制基因，该基因被突变或高甲基化灭活高达90％ CCRCC。而PVHL充当E3泛素连接酶适配器蛋白，促进降解的降解 缺氧诱导（HIFα）转录因子，其他关键的PVHL底物现在才出现，它们 在肾癌中的功能作用仍然不确定。在这里，我们确定一个锌指/同源域蛋白ZHX2 通过使用新开发的全基因组体外表达策略作为潜在的新型PVHL底物 再加上GST结合筛选。我们的初步数据表明PVHL与并降低 ZHX2以羟化酶活性依赖性方式，类似于HIFα蛋白的调节。在功能上 ZHX2的敲低阻碍细胞增殖，软琼脂生长和异种移植肿瘤的生长 肾脏癌细胞。重要的是，与CCRCC肿瘤相比 正常患者。从机械上讲，ZHX2与NF-KB的RELA/P65亚基相互作用并积极调节 PVHL损失诱导的Rela/P65核定位。 Chip-Seq和微阵列的集成分析也揭示了 ZHX2调节CCRCC中的NF-KB依赖性和独立途径。因此，我们假设 ZHX2通过NF-KB依赖和独立途径促进肾脏肿瘤发生 在VHL失活之后。这是针对Zhx2促促疾病的第一项研究， 专注于其在肾脏癌中PVHL丧失的关键作用。在特定目标1中，我们将研究 Zhx2以羟基化依赖性方式调节Zhx2的机制。在特定的目标2中，我们 将确定PVHL缺乏肾癌中失调的ZHX2的功能意义。在特定目标中 3，我们将确定ZHX2调节NF-KB依赖性和非依赖性信号的机制 PVHL损失后的肾脏肿瘤发生。成功完成此提案将提供重要的新 分子洞察与绝大多数CCRC相关的致癌机制以及 这种通常致命疾病的新疗法的潜力。