Defining Critical p53 Therapeutic Targets and Mechanisms

定义关键的 p53 治疗靶点和机制

• 批准号: 8986160
• 负责人: Clodagh O'Shea
• 金额: $ 43.65万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2019-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8986160
• 关键词: Adenovirus Infections; Adenoviruses; Binding; Binding Sites; CDKN2A gene; Cancer Patient; Cell Death; Cell Nucleus; Cells; Clinical; Clinical Trials; Combined Modality Therapy; DNA Binding; Development; Distant; Distant Metastasis; Dominant-Negative Mutation; Engineered Gene; Engineering; Evolution; Gene Targeting; Genetic Transcription; Genomics; Goals; Grant; Health; Heat-Shock Proteins 90; Heterochromatin; Histone Deacetylase Inhibitor; Human; Immunity; Inflammation; Left; Liver; MDM2 gene; Malignant Neoplasms; Mediating; Modification; Mus; Mutagenesis; Mutation; NBS1 gene; Neoplasm Metastasis; New Agents; Normal Cell; Nuclear; ONYX-015; Oncolytic; Oncolytic viruses; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphorylation; Point Mutation; Polymers; Pre-Clinical Model; Protein p53; Proteins; RNA; RNA Interference; Reporter; Specific qualifier value; Structure; Subgroup; TP53 gene; Technology; Testing; Treatment Efficacy; Tropism; Viral; Viral Genome; Viral Physiology; Virus; Virus Replication; Xenograft Model; base; cancer therapy; chemotherapy; improved; in vivo; inhibitor/antagonist; insight; killings; mouse model; mutant; neoplastic cell; new technology; new therapeutic target; novel; pre-clinical; prevent; promoter; receptor; response; targeted treatment; therapeutic target; tumor; uptake

DESCRIPTION (provided by applicant): The goal of this renewal is to exploit new insights into viral mechanisms that inactivate p53 to develop potent p53 tumor selective oncolytic adenovirus therapies. The p53 pathway is inactivated by mutations in almost every form of human cancer. However, despite this, there are still no approved rational therapies that target p53 defective tumor cells. Adenovirus E1B-55K targets p53 for degradation, which was thought to be essential for p53 inactivation and viral replication. On this premise, a �B-55K virus, ONYX-015, was tested in clinical trials as a p53 cancer therapy. However, patient responses did not correlate with the p53 status of their tumors. Although p53 is induced, it is inactive. Consequently, p53 does not determine the tumor selective replication of ONYX-015. As such, the enormous potential of a p53 selective could still be realized if the E1B-55K independent mechanisms through which adenovirus inactivates p53 are determined. This was the goal of the previous grant period. This led to the discovery that Ad5 encodes another protein, E4-ORF3, which inactivates p53 by forming a nuclear polymer that specifies de novo heterochromatin silencing of p53 target promoters, thereby preventing p53-DNA binding. With access denied, p53 is powerless to activate the transcription of downstream effectors to limit viral replication. These studies changed the longstanding definition of how p53 is inactivated in adenovirus infection. Here we propose to exploit these mechanistic insights to engineer E1B-55K/E4-ORF3 mutant adenoviruses as exciting new agents for p53 selective oncolytic viral therapy. This requires E1B-55K and E4-ORF3 mutations that selectively uncouple p53 inactivation from their other functions in viral replication. Previous studies revealed an E1B-55K H260A mutation that fulfills these criteria. To identify analogous mutations in E4-ORF3, we solved the atomic structure of Ad5 E4-ORF3. In Aim 1, we will use this to reveal novel structural motifs that silence p53 target genes. We have discovered that E4-ORF3 proteins from other Adenovirus subgroups do not inactivate p53. This provides a rational basis to identify Ad5 E4-ORF3 specific motifs that silence p53 target genes and engineer viruses with discrete E4-ORF3 mutations that prevent p53 inactivation. In Aim 2, we will combine E4ORF3 and E1B-55K mutations to develop novel Ad5 and Ad34 viruses and test their p53 selectivity in panels of normal and tumor cells. These studies will identify the critical functions of p53 that prevent viral replication and if they are disrupted by p53 and p14ARF mutations in cancer. Finally, in Aim 3, we will test novel p53 selective oncolytic viruses in preclinical mouse models of cancer. We will exploit new technologies to engineer additional genomic modifications that prevent viral uptake in the liver and limiting inflammation, enabling systemic delivery and expanded tumor tropisms. These viral therapies have the potential to be self-perpetuating, kill tumors through regulated cell death, and produce progeny that spread from within the tumor to distant micro-metastases. If results in pre-clinical models are promising, the goal is to test these agents in patients.

描述（由适用提供）：此更新的目的是利用对p53灭活的病毒机制的新见解，以开发潜在的p53肿瘤选择性溶瘤腺病毒疗法。几乎每种形式的人类癌症的突变使p53途径灭活。但是，这仍然没有靶向p53有缺陷肿瘤细胞的批准理性疗法。腺病毒E1B-55K靶向p53降解，这对于p53失活和病毒复制至关重要。在此前提下，在临床试验中测试了一种``B-55K on玛瑙-015）作为p53癌症治疗。但是，患者反应与肿瘤的p53状态无关。尽管p53是诱导的，但它是不活跃的。因此，p53不能确定Onyx-015的肿瘤选择性复制。因此，如果确定腺病毒灭活p53的E1B-55K独立机制，仍然可以实现p53选择性的增强潜力。这是上一个赠款期的目标。这导致了AD5编码另一种蛋白E4-ORF3的发现，该蛋白通过形成一种核聚合物来使p53失活，该核聚合物指定了从头杂色的p53靶启动子，从而防止p53-DNA结合。如果拒绝访问，p53无能激活下游效应的转录以限制病毒复制。这些研究改变了对腺病毒感染中p53如何失活的长期定义。在这里，我们建议探索这些机械见解，以对E1B-55K/E4-ORF3突变腺病毒作为p53选择性溶瘤病毒疗法的令人兴奋的新药物。这需要E1B-55K和E4-ORF3突变，这些突变有选择地将p53与病毒复制中的其他功能失活。先前的研究揭示了符合这些标准的E1B-55K H260A突变。为了鉴定E4-ORF3中的类似突变，我们解决了AD5 E4-ORF3的原子结构。在AIM 1中，我们将使用它来揭示静音p53靶基因的新型结构基序。我们发现来自其他腺病毒亚组的E4-ORF3蛋白不会灭活p53。这提供了合理的基础，以识别AD5 E4-ORF3特定基序，这些基序使p53靶基因和工程师病毒沉默，并具有离散的E4-ORF3突变，从而阻止p53失活。在AIM 2中，我们将结合E4ORF3和E1B-55K突变，以开发新型的AD5和AD34病毒，并在正常和肿瘤细胞的面板中测试其p53选择性。这些研究将确定p53的关键功能，以防止病毒复制，以及它们是否被癌症中p53和p14arf突变所破坏。最后，在AIM 3中，我们将在癌症的临床前小鼠模型中测试新型的P53选择性癌性病毒。我们将探索新技术，以设计其他基因组修饰，以防止肝脏中的病毒摄取并限制感染，从而实现全身性递送并扩大肿瘤的潮流。这些病毒疗法有可能自我延续，通过受调节的细胞死亡杀死肿瘤，并且 产生从肿瘤内传播到遥远的微焦点。如果临床前模型的结果是有希望的，那么目标是在患者中测试这些药物。