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

• 批准号: 8551655
• 负责人: Hua Lu
• 金额: $ 29.98万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 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/8551655
• 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; 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

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，两者毒性较大，副作用严重。此外，癌症患者的生存率几乎没有改善。因此，尽管具有挑战性，但开发更有效和更特异性的分子靶向疗法仍然非常重要。最重要的肿瘤抑制因子 p53 的失活是一种与癌症高度相关的分子改变，因为其基因在约 50% 的所有类型人类癌症中发生突变，而在剩余 50% 的含有野生型 TP53 的癌症中，其活性或水平通常显着降低。 p53失活主要是由于其两个主要抑制因子MDM2和MDMX的负反馈调节，它们在癌症中过度表达并形成介导p53泛素化和降解的复合物并直接抑制p53活性。 SIRT1 在某些癌症中高度表达，进一步促进了这种负调节，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 可用于筛选小分子，以开发抗癌疗法。事实上，我们最近的工作已经鉴定出一种名为 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。我们对 INZ 的进一步研究令人惊讶地揭示了另一个靶点 IMPDH2，它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，而核蛋白对 rRNA 加工至关重要。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，我假设新西兰移民局 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个假设。 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，因此在此目的中，我们将通过验证 INZ 作为 IMPDH2 的特异性抑制剂来确定 INZ 是否靶向 IMPDH2，巩固 INZ 对 IMPDH2 的抑制是否会降低 NS 水平并诱导随后的核糖体应激，并确定 RPL11 和 RPL5 是否对 INZ 诱导的 p53 激活至关重要。 2. 确定 INZ-14（一种更有效的 INZ 类似物）在 p53 激活和肿瘤抑制中的作用。为此，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，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，并在异种移植和原位肿瘤模型系统中测试INZ-14与阿霉素或β-辐射的协同作用。