Functions and Activities of p53 and Mdm2 in Normal and Cancer Cells

p53和Mdm 2在正常和癌细胞中的功能和活性。 p53蛋白是动物和人类癌症的主要抑制因子， 数百个基因的特异性转录调节因子，其产物介导细胞 结果如细胞周期停滞、细胞死亡、衰老、代谢变化、DNA修复和 其他的则与肿瘤抑制一致。虽然这类过程的有效调节剂， 细胞经历各种形式的遗传毒性或致癌应激，如果允许发挥功能 如果不加以控制，p53对细胞和组织可能是有害的，甚至是致命的。P53下紧 因此，控制与允许其在需要时发挥作用同样重要。这两种蛋白质 在抑制p53中起最核心作用的是Mdm 2及其同源物MdmX。一半以上 所有人类恶性肿瘤（取决于肿瘤类型）都携带野生型p53， 来自Mdm 2/X，可能作为细胞抑制剂或细胞毒性抗肿瘤剂有效。然而试剂 阻止Mdm 2与p53结合的药物（肽和小分子）尚未完全被发现。 被认为是有效的治疗剂。同样，临床上几乎没有有效的药物， 阻止突变型p53的致癌活性。此外，越来越多的证据表明， Mdm 2和MdmX在癌细胞中的p53非依赖性作用可用于治疗 诊断目的。本杰出研究者申请书中提出的工作 该奖项遵循了PI在实验室中对我们的理解的长期贡献历史 p53、Mdm 2和MdmX，一直延续到今天。未来的计划建立在新的 在PI的实验室的发现，并结合新的技术，以获得更多的全球和 关于p53/Mdm轴的机制信息。这项研究将扩大最近的 发现涉及（i）Mdm 2降解p53的新机制和可能性 这一发现可以导致新的治疗方法，防止野生型p53的Mdm 2降解，或 相反地促进Mdm 2降解致癌突变形式的p53，（ii）一系列的 携带独特的李-弗劳梅尼综合征p53突变的CRISPR衍生的细胞系;（iii）p53- Mdm 2和MdmX的独立作用，其可以预防或支持肿瘤发生，（iv） 作为p53靶点的长非编码RNA，可在人类中提供新的生物标志物 癌症;（v）了解p53如何在体外和体内识别其位点的新方法， (vi)在单分子分辨率下检查野生型和突变形式的 p53和Mdm 2的表达。该计划的长期目标将有望导致 用于诊断和治疗散发性和遗传性癌症的新工具。

Functions and Activities of p53 and Mdm2 in Normal and Cancer Cells. The p53 protein, a major suppressor of cancer in animals and humans, is a DNA sequence specific regulator of transcription of hundreds of genes whose products mediate cellular outcomes such as cell cycle arrest, cell death, senescence, metabolic changes, DNA repair and others that are consistent with tumor suppression. While a potent regulator of such processes in cells undergoing various forms of genotoxic or oncogenic stress, if allowed to function unchecked, p53 can be damaging or even lethal to cells and tissues. Keeping p53 under tight control is therefore as important as allowing it to function when needed. The two proteins that play the most central role in suppressing p53 are Mdm2 and its homologue MdmX. Over half of all human malignancies (depending on the tumor type) harbor wild-type p53, which if released from Mdm2/X, might be effective as a cytostatic or cytotoxic anti-tumor agent. Yet reagents (peptides and small molecules) that prevent Mdm2 from binding to p53 have not yet been fully realized as effective therapeutic agents. Similarly, there few effective drugs in the clinic that prevent the oncogenic activities of mutant p53. Further, increasing lines of evidence document p53-independent roles of Mdm2 and MdmX in cancer cells that can be exploited for therapeutic and diagnostic purposes. The work proposed in this application for an Outstanding Investigator Award follows a long history of contributions in the laboratory of the PI to our understanding p53, Mdm2 and MdmX that continue to the present day. The plans going forward build on new findings in the PI's lab, and incorporate novel technologies in order to gain more global and mechanistic information about the p53/Mdm axis. The research proposed will extend recent discoveries related to (i) a novel mechanism by which Mdm2 degrades p53 and the possibility that this finding can lead to new therapeutics that prevent Mdm2 degradation of wild-type p53 or conversely facilitate Mdm2 degradation of oncogenic mutant forms of p53, (ii) a series of CRISPR-derived cell lines harboring unique Li-Fraumeni-Syndrome p53 mutations; (iii) p53- independent roles of Mdm2 and MdmX that may either prevent or support oncogenesis, (iv) long non-coding RNAs that are p53 targets and which may provide new biomarkers in human cancers; (v) new approaches to understand how p53 identifies its sites in vitro and in vivo and, (vi) examination at single molecule resolution the localization of wild-type and mutant forms of p53 and Mdm2 after different stimuli. The long term goals of this program will hopefully lead to new tools for diagnosis and treatment of sporadic and inherited cancers.