Dual Targeting of the p53 pathway for development of anti-cancer therapy

双重靶向 p53 通路以开发抗癌疗法

基本信息

批准号：
8717615
负责人：
Hua Lu
金额：
$ 30.34万
依托单位：
TULANE UNIVERSITY OF LOUISIANA
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-26 至 2017-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8717615
关键词：
A549 Acetylation Address Adult Adverse effects Affect Animals Antineoplastic Agents Apoptosis Autophagocytosis Binding Biochemical Biological Models Cancer Patient Cell Cycle Cell Survival Cells Cessation of life Colon Carcinoma Colonic Neoplasms Complex Country Deacetylase Deacetylation Development Disease Down-Regulation Doxorubicin Enzyme Inhibition Feedback Foundations Gene Mutation Gene Targeting Genes Growth Guanosine Triphosphate H1299 HCT116 Cells Histone Deacetylase Human Image Implant Inosine Monophosphate Inosine Monophosphate Dehydrogenase Inhibitor Laboratories Light Lung Neoplasms MCF7 cell MDM2 gene Malignant Neoplasms Malignant neoplasm of lung Mediating MicroRNAs Modeling Molecular Mus Mutate Names Oxidoreductase Pathway interactions Patients Process Protein p53 Proteins Public Health Publishing Radiation therapy Regulation Reporting Ribosomal RNA Role Solid Stress Survival Rate TP53 gene Testing Tumor Suppression Tumor Suppressor Proteins Tumor-Derived Ubiquitin Ubiquitination Work Wound Healing Xenograft procedure analog cancer cell cancer therapy cell growth cellular targeting chemotherapy drug candidate improved interest irradiation member novel overexpression research study response ribosomal protein L11 senescence small molecule success tumor tumor growth

项目摘要

DESCRIPTION (provided by applicant): Cancer has been the leading cause of disease-related deaths in human beings, yet, its major non-surgery treatments have been chemotherapy and radiotherapy, both of which are quite toxic and cause severe side effects. Also, the survival rates of cancer patients have had little improvement. Thus, it still remains remarkably important, though challenging, to develop more potent and specific molecule-targeted therapies. The inactivation of the most important tumor suppressor p53 is one highly cancer-related molecular alteration, as its gene is mutated in ~50% of all types of human cancers while its activity or leve is often markedly reduced in the remaining 50% of cancers that harbor wild type TP53. The p53 deactivation is primarily due to the negative feedback regulation by its two chief suppressors, MDM2 and MDMX, which are over expressed in cancers and form a complex that mediates p53 ubiquitination and degradation as well as inhibits p53 activity directly. This negative regulation s further facilitated by SIRT1, which is highly expressed in some cancers, as the deacetylation of p53 by this deacetylase favors MDM2/MDMX-mediated ubiquitination of this protein. Thus, re-activation of p53 in cancers by targeting SIRT1 can be utilized to screen small molecules for the development of an anti-cancer therapy. Indeed, our recent work has identified a small molecule named Inauhzin (INZ) that inhibits the activity of SIRT1 and induces p53 acetylation, level and activity, leading to p53-dependent apoptosis and senescence in p53-containing human lung and colon cancer cells and suppressing the growth of xenograft lung and colon tumors. Our further studying INZ surprisingly reveals another target, IMPDH2, which is also highly expressed in human cancers. Our previous study shows that inhibition of this enzyme causes ribosomal stress by reducing the level of nucleostemin (NS), which is essential for rRNA processing. Consistent with this, INZ also binds to IMPDH2 and reduces NS levels, leading to the activation of the ribosomal stress-p53 pathway. In light of these interesting findings, I hypothesize that INZ can activate p53 by simultaneously targeting SIRT1 and IMPDH2 and thus eliminate cancer cells via a p53-dependent mechanism. We will test this hypothesis by addressing two specific aims. 1. To determine if INZ induces ribosomal stress and activates p53 by inhibiting IMPDH2 and downregulating NS. Since we have recently reported that INZ inhibits SIRT1 activity, here in this aim we will determine if INZ targets IMPDH2 by verifying INZ as a specific inhibitor of IMPDH2, consolidating if inhibition of IMPDH2 by INZ reduces NS levels and induces consequent ribosomal stress, and determining if RPL11 and RPL5 are critical for INZ-induced p53 activation. 2. To determine the role of INZ-14, a more potent INZ analog, in p53 activation and tumor suppression. In this aim, we will test our newly synthesized INZ derivatives, particularly potent INZ-14, by further modifying it, characterizing it in our established biochemical, cellular and animal tumor model systems, and testing the cooperative effect of INZ-14 with doxorubicin or ¿-irradiation in xenograft and orthotopic tumor model systems.

描述（申请人提供）：癌症一直是人类疾病相关死亡的主要原因，但其主要的非手术治疗方法是化疗和放疗，这两种疗法毒性很大，会产生严重的副作用。癌症患者的生存率几乎没有改善，因此，开发更有效和特异性的分子靶向疗法仍然非常重要，但最重要的肿瘤抑制因子 p53 是一种癌症相关分子。 p53 的失活主要是由于负反馈调节，因此它的基因在约 50% 的所有类型的人类癌症中发生突变，而在其余 50% 的含有野生型 TP53 的癌症中，其活性或水平通常显着降低。其两个主要抑制因子 MDM2 和 MDMX 在癌症中过度表达，形成介导 p53 泛素化和降解的复合物，并直接抑制 p53 活性。 SIRT1 在某些癌症中高表达，因为这种脱乙酰酶对 p53 的脱乙酰作用有利于 MDM2/MDMX 介导的该蛋白的泛素化，因此，通过靶向 SIRT1 重新激活癌症中的 p53 可用于筛选。事实上，我们最近的工作已经确定了一种名为 Inauhzin (INZ) 的小分子，它可以抑制SIRT1 的活性并诱导 p53 乙酰化、水平和活性，导致含有 p53 的人肺癌和结肠癌细胞中 p53 依赖性细胞凋亡和衰老，并抑制异种移植肺和结肠肿瘤的生长。我们的进一步研究令人惊讶地揭示了另一个目标， IMPDH2 在人类癌症中也高度表达，我们之前的研究表明，抑制这种酶会降低核蛋白 (NS) 的水平，从而导致核糖体应激。与此一致的是，INZ 还与 IMPDH2 结合并降低 NS 水平，从而激活核糖体应激-p53 通路。鉴于这些有趣的发现，我着迷于 INZ。可以通过同时靶向 SIRT1 和 IMPDH2 来激活 p53，从而通过 p53 依赖性机制消除癌细胞。我们将通过解决两个具体目标来检验这一假设：1. 确定 INZ 是否通过抑制 IMPDH2 和下调 NS 来诱导核糖体应激并激活 p53。由于我们最近报道了 INZ 抑制 SIRT1 活性，因此我们将通过验证 INZ 作为特定抑制剂来确定 INZ 是否靶向 IMPDH2。 2. 确定 INZ-14（一种更有效的 INZ 类似物）的作用。，在 p53 激活和肿瘤抑制中，我们将通过进一步修饰来测试我们新合成的 INZ 衍生物，特别是有效的 INZ-14。它，在我们建立的生化、细胞和动物肿瘤模型系统中对其进行表征，并测试 INZ-14 与阿霉素或 ¿ -异种移植和原位肿瘤模型系统中的照射。