基于p97-NPL4复合物组装的胃癌治疗靶点验证与药物筛选

Protein homeostasis is critical for cancer cell survival and growth. It is established that the p97-NPL4 complex plays a vital role in protein homeostasis control, especially in the regulation of ubiquitin-proteasome mediated protein degradation, endoplasmic reticulum-associated degradation (ERAD) and autophagy. Over the past decade, the applicant has been focusing on signaling mechanism of tumorigenesis, and particularly on therapeutic strategies against gastrointestinal cancers (Cancer Cell, Nat Commun). Recently, the applicant has been working on the function and mechanism of p97-related complexes. We have solved the crystal structure of p97-Npl4 complex and revealed the essentiality of proper assembly of the complex for its regulatory roles in the NF-kB signaling (EMBO J, JBC). Furthermore, our preliminary study showed that targeting p97-NPL4 complex assembly can inhibit the growth of gastric cancer cells (unpublished data). As an ATPase, p97 is involved via different cofactor including NPL4 in multiple physiological processes, thus targeting the ATPase activity of p97 would therefore result inserious side effect with lower level of specificity. In this project, taking advantage of her previous research knowledge on p97-NPL4 complex and gastric cancer, the applicant will continue to validate the antitumor efficiency of targeting the p97-NPL4 interface, mainly by screening the chemical compounds disrupting p97-NPL4 complex assembly, and assessing their antitumor effect through gastric patient-derived xenograft (PDX) model, aiming to find effective, specific and low-toxic drugs for gastric cancer therapy and provide considerable insights into the treatment of advanced gastric cancer.

蛋白质稳态异常与肿瘤发生密切相关。p97-NPL4是蛋白质稳态调控的关键复合物。申请人长期致力发现和验证胃癌诊断治疗新靶标（Cancer Cell、Nat Commun），近期研究p97-NPL4复合物的功能与机制，解析其三维结构，明确其对NF-kB通路的调控效应依赖于复合物组装（EMBO J、JBC），并进一步发现靶向p97-NPL4组装可有效抑制胃癌细胞生长（未发表数据）。考虑到p97可结合包括NPL4在内的不同辅因子而调控众多生命过程，抑制其ATP酶活性易导致明显毒副作用且特异性差。因此，本项目中申请人拟在前期工作基础上，探究以p97-NPL4互作界面为靶标治疗胃癌的可行性，并着重筛选靶向复合物组装的小分子化合物，进而通过患者肿瘤PDX模型对筛选得到的化合物进行验证评估和结构优化，旨在获得特异性高、针对性强、毒副作用小的新型广谱抗癌药物，为突破中晚期胃癌的治疗瓶颈提供思路和基础。

胃癌是常见的恶性肿瘤之一，目前胃癌的治疗仍存在诸多问题，是现代医学和生命科学所面临的巨大挑战。项目负责人长期致力于发现和验证胃癌新的诊断治疗靶标，针对p97相关复合物的功能与机制展开的前期研究解析了p97-NPL4复合物的三维结构，明确p97对NF-κB通路的调控作用依赖该复合物的正确组装，并同时发现靶向p97和NPL4正确组装可有效抑制胃癌细胞的生长。考虑到p97的ATP酶活性为生物体多种生命过程所必须，抑制其活性易导致明显的毒副作用且特异性差。本项目以p97与NPL4相互作用的界面为靶标在分子水平上筛选针对该复合物组装的抑制剂，发现以p97和NPL4相互作用界面为靶标治疗胃癌具有可行性，筛选获得了靶向p97-NPL4复合物组装的小分子先导化合物，并对这些化合物的有效官能团进行了确认和优化。在此基础上，又通过患者原代肿瘤组织的肿瘤移植模型等小鼠疾病模型，对化合物的靶向性、药效及毒性等进行了评估，为突破中晚期胃癌的治疗瓶颈提供思路和基础。