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，然而，其主要的非手术治疗方法是化疗和放疗，这两种方法都有很大的毒性和严重的副作用。此外，癌症患者的存活率也几乎没有改善。因此，尽管具有挑战性，但开发更有效和特异性的分子靶向治疗仍然非常重要。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，因为其基因在所有类型的人类癌症中约50%发生突变，而其活性或水平在其余50%具有野生型TP53的癌症中通常显着降低。p53失活主要是由于它的两个主要抑制因子MDM2和MDMX的负反馈调控，它们在癌症中过度表达，形成一个复合物，介导p53的泛素化和降解，并直接抑制p53的活性。SIRT1进一步促进了这种负调控，SIRT1在某些癌症中高度表达，因为这种去乙酰化酶使p53去乙酰化有利于MDM2/ mdmx介导的该蛋白泛素化。因此，通过靶向SIRT1在癌症中重新激活p53可以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发现了一种名为Inauhzin （INZ）的小分子，它可以抑制SIRT1的活性，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依赖性的凋亡和衰老，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，抑制该酶通过降低核干素（NS）的水平导致核糖体应激，核干素是rRNA加工所必需的。与此一致的是，INZ也与IMPDH2结合并降低NS水平，导致核糖体应激-p53通路的激活。根据这些有趣的发现，我假设INZ