针对肿瘤高氧化应激水平的NQO1靶向ROS诱导剂的设计、合成与生物活性研究

In this project we propose that it is of important to pay great attention to the selectivity between NQO1 and CPR during the research and development of NQO1-targeted ROS-inducers as antitumor agents and thus to avoid the potential hepatotoxicity that caused by CPR. However, the currently reported NQO1 substrates can also be catalyzed by CPR and showed poor NQO1/CPR selectivity. Our research group has recently discovered the quinonoid substrate DDO-7134 and novel non-quinonoid substrate 000A-0055 that showed appropriate NQO1/CPR selectivity and low toxicity toward normal liver cells. Taking these two compounds as the lead compounds, we plan to further carry on the structure-activity relationship (SAR) and structure-selectivity relationship (SSR) studies by analyzing the aspects of molecular shape and electric property for target-substrate interaction and redox potential for substrates, and to optimize both of the NQO1-targeted ROS inducing activity and NQO1/CPR selectivity. With fully consideration of the in vitro and in vivo antitumor activity, NQO1/CPR selectivity, and druggable properties such as aqueous solubility, log D, permeability, ADME pharmacokinetic properties and hepatotoxicity during the structural optimization, we prospect to discover highly selective NQO1-targeted ROS-inducers with novel structures, high potency and low toxicity as promising antitumor candidates for the treatment of NQO1-overexpressed cancers and drug-resistant cancers as well. Utilizing the small molecular fluorescent probe for NQO1 recently developed by our group, We plan to explore the application of the antitumor candidates in individualized treatment for NQO1-overexpressed cancers.

本项目提出NQO1靶向ROS诱导剂的抗肿瘤药物研发应注重NQO1/CPR选择性，以避免CPR介导的肝毒性。目前报道的NQO1醌底物普遍缺乏NQO1/CPR选择性。本课题组前期发现了具有一定NQO1/CPR选择性的醌类底物DDO-7134及结构新颖的非醌底物000A-0055，对正常肝脏细胞毒性较小。本项目将以这两个化合物为先导物，从靶标-底物结合的形状匹配、电性匹配及底物分子的氧化还原电位角度，深入研究“构-效”及“构-选择性”关系，优化NQO1靶向ROS诱导活性及NQO1/CPR选择性，综合考虑体内外抗肿瘤活性及成药性质（水溶性、logD、透膜性等理化性质，ADME药代动力学性质及肝毒性等）进行结构优化，以期发现高效低毒、结构新颖的高选择性NQO1靶向ROS诱导剂作为抗肿瘤及抗耐药肿瘤的候选药物，结合本课题组前期开发的NQO1小分子荧光探针，探索其在NQO1高表达肿瘤个体化治疗中的应用。

本项目创新提出NQO1靶向ROS诱导剂的抗肿瘤药物研发应注重NQO1/CPR选择性，以避免现有NQO1醌底物因脱靶被CPR还原介导的肝毒性。本项目研究：1）突破NQO1酶底物为醌类结构的思维局限，在国际上率先创新发现了苯邻二氰类“NQO1酶非醌底物”，其中“羰基-氮原子”构成NQO1还原的药效基团，NQO1/CPR选择性可超过50倍，大幅度提升了安全性，作为肿瘤靶向ROS诱导剂，可用于NQO1高表达的（耐药）非小细胞肺癌的个性化治疗；2）基于分子动力学模拟创新发现“L型分子形状”底物可更好地与NQO1催化口袋契合，提出在侧链引入亲水性基团，特别是引入含氮脂肪环，其在生理条件下可被质子化，既可通过cation-pi作用增强NQO1靶向活性及NQO1/CPR选择性（>20倍），还可大幅度增强底物的水溶性，避免醌类底物因溶解性差而使用助溶剂HP-β-CD导致的溶血毒副作用；3）探索并总结了底物结构与NQO1/CPR选择性的“构-选择性”规律：底物氧化还原电位高于-1.20V、底物母核中引入吸电子基团、将底物设计为“L型分子形状”均有利于提升NQO1/CPR选择性；4）本项目研究设计、合成并评价了102个新型非醌结构及邻醌结构NQO1靶向目标化合物，通过兼顾NQO1靶向活性、选择性及成药性的结构优化，获得了4个具有良好体内抗肿瘤活性及安全性的候选分子，可用于进一步系统性临床前评价研究；5）首次将NQO1靶向近红外探针与NQO1底物候选药物联用，用于NQO1高表达肿瘤的个性化诊疗。这为NQO1靶向ROS诱导剂抗肿瘤创新药物研发奠定了良好的基础。在该项目资助下，共发表NQO1及ROS通路相关的SCI论文8篇，其中有3篇发表在J Med Chem，有4篇发表在Eur J Med Chem；申请国家发明专利3项，其中授权1项；培养博士研究生2名，硕士研究生3名；项目负责人获得江苏省杰出青年基金资助。