新型MEK抑制剂的设计合成及高效抗肿瘤的分子机制研究

MEK inhibitors are key drugs for the targeted treatment of more than 30% of human malignant tumors. However, the inability of drug molecules to bind to MEK kinase leads to unsatisfactory antitumor efficacy and unclear action mechanism of existing MEK inhibitors. Increasing the dosage or combination can improve the therapeutic effect but bring serious side effects. This project takes improving the activity of MEK inhibitors as the starting point. The reason of low activity is analyzed and a novel MEK inhibitor is synthesized by means of the techniques of pharmaceutical chemistry, molecular biology and fluorescence visualization. The efficient kinase properties, antitumor activity, and tissue safety of the drug have been preliminarily characterized. The drug effects on cellular signaling pathways will be analyzed at the protein and gene levels. Furthermore, dynamic tracing of drug action at the cellular and in vivo levels will be carried out using laser confocal and fluorescence visualization techniques, to intuitively reveal the dual inhibitory molecular mechanism which resulted in high antitumor efficiency. The successful implementation of this project will provide design ideas and specific attempts to solve the clinical problems of low MEK inhibitors activity from the drug design, synthesize new drugs, systematically characterize the drug efficiency, and clarify the molecular mechanism. It will lay the scientific foundation for the drug research of MEK inhibitors and the molecular targeted therapy of MAPK pathway-related malignant tumors.

MEK抑制剂是靶向治疗30%以上的人类恶性肿瘤的关键药物，但药物分子无法牢固结合MEK激酶从而导致现有MEK抑制剂的抗肿瘤活性低，且缺乏明晰的作用机理，增大剂量或联合用药在改善药效的同时带来较大的毒副作用。本项目以改善MEK抑制剂的活性问题为切入点，分析导致MEK抑制剂活性低的分子结构原因，采用药物化学、分子生物学和荧光可视化等技术手段，合成新型的MEK抑制剂；表征药物高效的激酶特性、抗肿瘤活性和对正常组织的安全性；从蛋白和基因水平分析药物对细胞信号通路的影响，进一步采用激光共聚焦和荧光可视化技术，在细胞和活体水平动态示踪药物的作用机理，直观地揭示药物高效抗肿瘤的双靶点抑制分子机制。本项目的顺利实施将从药物分子的源头上为解决MEK抑制剂活性低的临床问题提供设计思路并作出具体尝试，合成新型高效且机理明确的MEK抑制剂，为新药研究和与MAPK通路相关的恶性肿瘤分子靶向治疗奠定科学基础。

MEK抑制剂是靶向治疗30%以上人类恶性肿瘤的关键药物，已有多种MEK抑制剂候选分子被合成，但目前仅有4种被美国FDA批准用于MAPK通路高活化恶性肿瘤的单药或联合治疗，究其原因主要是药物分子无法牢固结合MEK激酶从而导致现有MEK抑制剂的抗肿瘤活性低，且缺乏明晰的作用机理，增大剂量或联合用药在改善药效的同时带来较大毒副作用。本项目以改善MEK抑制剂的活性问题为切入点，分析导致MEK抑制剂活性低的分子结构原因，以处于III期临床试验阶段且具有有利核心结构的MEK抑制剂AZD6244为先导，在此基础上进行结构改进，用S原子取代苯并噻唑杂环上N-甲基，生成苯并噻唑核，用-F和-I 取代苯胺上的-Cl和-Br，合成一种新型MEK抑制剂HL-001-087，分子式为 C15H11SF2IN4O3，分子量为492；该药物可与MEK激酶通过氢键、静电、偶极和边对面芳香相互作用等几种关键作用紧密结合从而高选择性且高效地抑制MEK激酶（IC50 = 1.1 nmol/L），对Pim1也有较好抑制作用（IC50 = 1.1 μmol/L）；抗肿瘤活性结果显示，HL-001-087具有优于AZD6244 2-3个数量级的抗结直肠癌细胞活性和高20倍的体内抗肿瘤活性，对正常组织安全低毒；采用分子生物学技术，在蛋白和基因水平明确了HL-001-087通过RAS/RAF/MEK/ERK/IRS-1/PI3K/AKT/AMPK/IL-23/STAT3/Pim1机制同时抑制本征活化的MAPK通路和由于ERK被抑制而代偿激活的Pim1通路，进一步采用激光共聚焦和荧光可视化技术，在细胞和活体水平动态可视示踪并直观揭示该药高效抗肿瘤的MEK/Pim1双靶点抑制分子机制；该双靶点特性可实现单药双抑制从而优于单药或双药联合体系，并克服了联合体系的比例优化和毒性叠加问题。本项目设计合成新型高效且机理明确的MEK抑制剂，药物新、活性高、毒性低，从分子源头上为解决MEK抑制剂活性低的临床问题提供设计思路并作出具体尝试，为新药研究和与MAPK通路相关的恶性肿瘤分子靶向治疗奠定科学基础，具有广泛的临床应用前景。