Control of mutant p53 stability via the mevalonate pathway-DNAJA1 axis

通过甲羟戊酸途径-DNAJA1 轴控制突变体 p53 的稳定性

• 批准号: 9523990
• 负责人: Tomoo Iwakuma
• 金额: $ 35万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-03-09 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9523990
• 关键词: Acetylation; Affect; Apoptosis; Attenuated; Binding; Cells; Cholesterol; DNA; DNA Binding Domain; Data; Docking; EP300 gene; Family; Goals; Head and Neck Squamous Cell Carcinoma; Human; Immunohistochemistry; In Vitro; Knock-out; Link; Lipids; Lysine; Malignant - descriptor; Malignant Epithelial Cell; Malignant Neoplasms; Maps; Mass Spectrum Analysis; Mevalonate kinase; Missense Mutation; Molecular; Molecular Chaperones; Molecular Conformation; Mutate; Mutation; Oncogenic; Pathway interactions; Patients; Pharmaceutical Preparations; Play; Production; Proliferation Marker; Property; Protein Isoprenylation; Protein p53; Proteins; Publications; Regulation; Role; Signal Pathway; Structure; Supplementation; Survival Rate; TP53 gene; Testing; Tissues; Tumor Suppression; Xenograft procedure; base; cancer addiction; cancer cell; gain of function; high throughput screening; improved; in vivo; inhibitor/antagonist; inorganic phosphate; knock-down; mevalonate; misfolded protein; mouse model; mutant; new therapeutic target; novel; outcome forecast; overexpression; screening; small molecule libraries; therapeutic target; tumor; tumor progression; ubiquitin ligase; virtual

The overall 5-year survival rate of patients with head and neck squamous cell carcinoma (HNSCC) is less than 50%, and ~75% of human HNSCC cases have mutations in the tumor suppressor p53. The vast majority of p53 mutations are missense mutations that show oncogenic activities, with strong correlation with poor prognosis in patients with HNSCC. Recent evidence indicates that stabilization of mutant p53 (mutp53) in tumors is crucial for its oncogenic activities, while its knockdown attenuates tumor progression. Although there are numerous publications on the function and regulation of wild-type p53 (wtp53), little is known about mechanisms controlling mutp53 levels in tumors and the workable strategies that induce mutp53 degradation. The goal of this proposal is to discover efficient strategies to specifically degrade mutp53 in HNSCC and elucidate the underlying mechanisms. To identify compounds that reduce mutp53 levels, we performed high throughput screening of chemical libraries and identified “statins”, a class of drugs that inhibit cholesterol production, as degradation inducers of structurally misfolded mutp53 proteins. Statins showed minimal effects on wtp53 and DNA contact mutp53 with native structure. Reduction in mevalonte-5-phosphate (MVP), but not other metabolites in the mevalonate (MV) pathway, triggered mutp53 degradation by CHIP ubiquitin ligase in a protein prenylation-independent manner. Statins also inhibited binding of mutp53 to DNAJA1, a molecular chaperone of the Hsp40 family which plays a role in refolding of misfolded proteins. Indeed, mutp53 degradation by statins was nullified by MVP supplementation, as well as by DNAJA1 overexpression. These data suggest that MVP positively regulates the DNAJA1-mutp53 binding and that DNAJA1 stabilizes misfolded mutp53. However, it is still unclear how reduced MVP leads to inhibition of DNAJA1-mutp53 binding. Based on our compelling preliminary data showing that reduction in MVP by knockdown of mevalonate kinase (MVK) increased acetylation of mutp53, we hypothesize that acetylation of mutp53 upon MVP reduction inhibits the mutp53-DNAJA1 binding, which promotes mutp53 degradation, leading to tumor suppression. We will test this hypothesis and establish the role of DNAJA1 in the malignant progression of HNSCC cells. In Aim 1, we will determine the mechanism by which reduced MVP leads to inhibited binding of mutp53 with DNAJA1 to induce mutp53 degradation and tumor suppression. In Aim 2, we will test the hypothesis that DNAJA1 promotes HNSCC progression in a misfolded mutp53-dependent manner. In Aim 3, we will characterize potential DNAJA1 inhibitors identified through molecular docking studies for their abilities to bind to DNAJA1, induce mutp53 degradation, and reduce the malignant properties of HNSCC cells. Completion of this study will reveal a novel mechanism of mutp53 stabilization via unexpected functional link between MVP and DNAJA1 and will establish the MV pathway and DNAJA1 as novel therapeutic targets for mutp53-carrying cancers. This study may also identify a DNAJA1 inhibitor as a potential compound that can be used for HNSCC therapy.

头颈鳞状细胞癌（HNSCC）患者的总体 5 年生存率低于 50% 和~75% 的人类 HNSCC 病例的肿瘤抑制因子 p53 存在突变。绝大多数 p53 突变是显示致癌活性的错义突变，与较差的致癌活性有很强的相关性。 HNSCC 患者的预后。最近的证据表明突变体 p53 (mutp53) 的稳定性 肿瘤对其致癌活性至关重要，而其敲低则可减弱肿瘤进展。虽然有 关于野生型 p53 (wtp53) 的功能和调控的出版物有很多，但人们对此知之甚少 控制肿瘤中 mutp53 水平的机制以及诱导 mutp53 降解的可行策略。 该提案的目标是发现特异性降解 HNSCC 中 mutp53 的有效策略， 阐明根本机制。为了识别降低 mutp53 水平的化合物，我们进行了高 对化学库进行通量筛选并鉴定出“他汀类药物”，这是一类抑制胆固醇的药物 作为结构错误折叠的 mutp53 蛋白的降解诱导剂。他汀类药物效果甚微 wtp53 和 DNA 使 mutp53 与天然结构接触。 5-磷酸甲羟戊酸 (MVP) 减少，但不减少 甲羟戊酸 (MV) 途径中的其他代谢物，通过 CHIP 泛素连接酶触发 mutp53 降解 蛋白质异戊二烯化独立方式。他汀类药物还抑制 mutp53 与 DNAJA1 的结合，DNAJA1 是一种分子 Hsp40 家族的分子伴侣，在错误折叠蛋白质的重折叠中发挥作用。确实，mutp53 通过补充 MVP 以及 DNAJA1 过表达，他汀类药物的降解作用被抵消。这些 数据表明 MVP 正向调节 DNAJA1-mutp53 结合，并且 DNAJA1 稳定错误折叠 mutp53。然而，目前尚不清楚 MVP 的减少如何导致 DNAJA1-mutp53 结合的抑制。基于 我们令人信服的初步数据表明，通过敲除甲羟戊酸激酶 (MVK) 可减少 MVP mutp53 的乙酰化增加，我们假设 MVP 还原后 mutp53 的乙酰化会抑制 mutp53-DNAJA1 结合，促进 mutp53 降解，从而抑制肿瘤。我们将测试这个 假设并建立 DNAJA1 在 HNSCC 细胞恶性进展中的作用。在目标 1 中，我们将 确定减少 MVP 导致 mutp53 与 DNAJA1 结合受到抑制的机制，以诱导 mutp53 降解和肿瘤抑制。在目标 2 中，我们将检验 DNAJA1 促进的假设 HNSCC 以错误折叠的 mutp53 依赖性方式进展。在目标 3 中，我们将描述潜力 通过分子对接研究鉴定出 DNAJA1 抑制剂能够与 DNAJA1 结合，诱导 mutp53降解，降低HNSCC细胞的恶性特性。完成这项研究将揭示 通过 MVP 和 DNAJA1 之间意想不到的功能联系实现 mutp53 稳定的新机制，并将 建立 MV 通路和 DNAJA1 作为携带 mutp53 的癌症的新治疗靶点。这项研究 还可能将 DNAJA1 抑制剂鉴定为可用于 HNSCC 治疗的潜在化合物。