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

基本信息

批准号：
9382004
负责人：
Qing Zhang
金额：
$ 41.12万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-30 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9382004
关键词：
Accounting Adaptor Signaling Protein Address Agar Automobile Driving Binding CCL2 gene Cancer Patient Cell Line Cell Proliferation Cells ChIP-seq Chronic Clear Cell Conventional (Clear Cell) Renal Cell Carcinoma Coupled 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 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 TNFRSF5 gene Transcription Repressor/Corepressor Tumor Suppressor Genes Tumor Suppressor Proteins Tumor Tissue Ubiquitination Up-Regulation Zinc Fingers cancer therapy carcinogenesis cytotoxic 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

项目摘要

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.

项目概要透明细胞肾细胞癌 (ccRCC) 约占所有肾癌的 85%，具有耐药性 ccRCC 的一个特点是 von Hippel 失活。 Lindau (VHL) 肿瘤抑制基因，高达 90% 的患者因突变或高甲基化而失活而 pVHL 作为 E3 泛素连接酶接头蛋白发挥作用，促进 ccRCC 的降解。缺氧诱导（HIFα）转录因子，其他关键的 pVHL 底物现在才刚刚出现，它们的在癌症中的功能作用仍不清楚。在这里，我们鉴定了一种锌指/同源结构域蛋白 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 底物结合 GST 结合筛选，我们的初步数据表明 pVHL 会相互作用并降解。 ZHX2 以羟化酶活性依赖的方式，在功能上类似于 HIFα 蛋白的调节。 ZHX2 的敲低可阻止 pVHL 缺陷的细胞增殖、软琼脂生长和异种移植肿瘤生长重要的是，与 ccRCC 肿瘤细胞相比，ZHX2 表达水平显着升高。从机制上讲，ZHX2 与 NF-kB 的 RelA/p65 亚基相互作用并正向调节。 ChIP-Seq 和微阵列的综合分析也揭示了 pVHL 丢失诱导的 RelA/p65 核定位。 ZHX2 调节 ccRCC 中 NF-kB 依赖性和独立通路。 ZHX2 通过 NF-kB 依赖和独立途径促进肾肿瘤发生这是第一项针对 ZHX2 促癌功能的研究。在具体目标 1 中，我们将重点关注其在肾癌中 pVHL 缺失下游的关键作用。在具体目标 2 中，我们研究了 pVHL 以羟基化依赖性方式调节 ZHX2 的机制。将确定 ZHX2 失调在 pVHL 缺陷型肾癌中的功能意义。 3，我们将确定ZHX2调节NF-kB依赖性和非依赖性信号传导的机制该提案的成功完成将提供重要的新成果。对与大多数 ccRCC 相关的致癌机制以及针对这种典型致命疾病的新疗法的潜力。