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: 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
• 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

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.

项目总结