Defining Critical p53 Therapeutic Targets and Mechanisms

定义关键的 p53 治疗靶点和机制

基本信息

批准号：
9180687
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
项目类别：
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/9180687
关键词：
Adenovirus Infections Adenoviruses Binding Binding Sites CDKN2A gene Cancer Model Cancer Patient Cell Death Cell Nucleus Cells Clinical Clinical Trials Combined Modality Therapy DNA Binding Development Distant Distant Metastasis Dominant-Negative Mutation Engineering Evolution Gene Targeting Genetic Transcription Genomics Goals Grant Heat-Shock Proteins 90 Heterochromatin Histone Deacetylase Inhibitor Human Immunity Inflammation 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 cancer therapy chemotherapy genotoxicity improved in vivo inhibitor/antagonist insight killings mouse model mutant neoplastic cell new technology new therapeutic target novel pre-clinical prevent promoter public health relevance receptor response small hairpin RNA targeted treatment therapeutic target tumor uptake

项目摘要

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（由申请人提供）：本次更新的目标是利用对 p53 失活的病毒机制的新见解，以开发有效的 p53 肿瘤选择性溶瘤腺病毒疗法。 p53 途径几乎会因人类癌症的突变而失活。因此，目前还没有针对 p53 缺陷肿瘤细胞的批准合理疗法，腺病毒 E1B-55K 可以靶向 p53 进行降解，而这被认为是 p53 所必需的。在此前提下，在临床试验中测试了一种 �B-55K 病毒 ONYX-015 作为 p53 癌症疗法，尽管 p53 是被诱导的，但患者的反应与其肿瘤的 p53 状态无关。经检查，p53 不决定 ONYX-015 的肿瘤选择性复制，因此，如果 E1B-55K 仍然可以实现 p53 选择性的巨大潜力。确定了腺病毒灭活 p53 的独立机制，这导致了 Ad5 编码另一种蛋白质 E4-ORF3 的发现，该蛋白质通过形成指定从头异染色质沉默的核聚合物来灭活 p53。 p53 目标启动子，阻止 p53-DNA 结合，由于访问被拒绝，p53 无法激活下游效应子的转录以限制病毒复制。在这里，我们建议利用这些机制见解来设计 E1B-55K/E4-ORF3 突变腺病毒，作为 p53 选择性溶瘤病毒治疗的令人兴奋的新药物。先前的研究揭示了一种 E1B-55K H260A 突变，可以选择性地将 p53 失活与其在病毒复制中的其他功能分开。为了识别 E4-ORF3 中的类似突变，我们解决了 Ad5 E4-ORF3 的原子结构。在目标 1 中，我们将使用它来揭示沉默 p53 靶基因的新结构基序。来自其他腺病毒亚群的蛋白质不会使 p53 失活，这为鉴定 Ad5 E4-ORF3 特异性基序（沉默 p53 靶基因）和用离散的病毒工程提供了合理的基础。防止 p53 失活的 E4-ORF3 突变在目标 2 中，我们将结合 E4ORF3 和 E1B-55K 突变来开发新型 Ad5 和 Ad34 病毒，并在正常细胞和肿瘤细胞中测试它们的 p53 选择性。 p53 阻止病毒复制，以及它们是否被癌症中的 p53 和 p14ARF 突变破坏。最后，在目标 3 中，我们将测试新型 p53 选择性。我们将利用新技术来设计额外的基因组修饰，以防止病毒在肝脏中的摄取并限制炎症，从而实现全身传递并扩大肿瘤趋向性。通过调节细胞死亡来杀死肿瘤，以及产生从肿瘤内部扩散到远处微转移的后代。如果临床前模型的结果有希望，我们的目标是在患者中测试这些药物。