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.

头颈部鳞状细胞癌（HNSCC）患者的总体5年生存率低于 约50%和约75%的人HNSCC病例在肿瘤抑制因子p53中具有突变。绝大多数 p53突变是显示致癌活性的错义突变，与恶性肿瘤有很强的相关性。 HNSCC患者的预后。最近的证据表明，稳定突变型p53（mutp 53）， 在肿瘤中，它的致癌活性是至关重要的，而它的敲低减弱了肿瘤的进展。虽然 关于野生型p53（wtp 53）的功能和调节的出版物很多，但对野生型p53的功能和调节知之甚少。 肿瘤中控制mutp 53水平的机制和诱导mutp 53降解的可行策略。 该提案的目标是发现特异性降解HNSCC中mutp 53的有效策略， 阐明潜在的机制。为了鉴定降低mutp 53水平的化合物，我们进行了高 通过筛选化学文库并鉴定“他汀类药物”，一类抑制胆固醇的药物 作为结构错误折叠的mutp 53蛋白的降解诱导剂。他汀类药物的作用微乎其微 在wtp 53和DNA接触mutp 53与天然结构。甲羟戊酸-5-磷酸（MVP）减少，但未 甲羟戊酸（MV）途径中的其他代谢物在细胞中通过CHIP遍在蛋白连接酶触发mutp 53降解 蛋白质异戊烯化不依赖的方式。他汀类药物还抑制mutp 53与DNAJA 1的结合，DNAJA 1是一种分子标记物。 Hsp 40家族的伴侣蛋白，其在错误折叠的蛋白质的重折叠中起作用。事实上，mutp 53 他汀类药物的降解被MVP补充以及DNAJA 1过表达所抵消。这些 数据表明MVP正调控DNAJA 1-mutp 53结合，DNAJA 1稳定错误折叠 mutp53.然而，目前还不清楚减少MVP如何导致DNAJA 1-mutp 53结合的抑制。基于 我们令人信服的初步数据显示，通过敲低甲羟戊酸激酶（MVK）降低MVP， 增加了mutp 53的乙酰化，我们推测MVP减少时mutp 53的乙酰化抑制了 mutp 53-DNAJA 1结合，其促进mutp 53降解，导致肿瘤抑制。我们将测试这个 假设并建立DNAJA 1在HNSCC细胞恶性进展中的作用。在目标1中，我们 确定MVP降低导致mutp 53与DNAJA 1结合抑制的机制，以诱导 mutp 53降解和肿瘤抑制。在目标2中，我们将检验DNAJA 1促进 HNSCC以错误折叠的mutp 53依赖性方式进展。在目标3中，我们将描述潜在的 通过分子对接研究鉴定DNAJA 1抑制剂结合DNAJA 1、诱导 mutp 53降解，并降低HNSCC细胞的恶性性质。这项研究的完成将揭示 通过MVP和DNAJA 1之间意想不到的功能连接的mutp 53稳定的新机制， 建立MV途径和DNAJA 1作为携带mutp 53的癌症的新治疗靶点。本研究 还可以鉴定DNAJA 1抑制剂作为可用于HNSCC治疗的潜在化合物。