Abstract：
Blockade of the programmed cell death-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway is an attractive strategy for immunotherapy, but the clinical application of small molecule PD-1/PD-L1 inhibitors remains unclear. In this work, based on BMS-202 and our previous work YLW-106, a series of compounds with benzo[d]isothiazol structure as scaffold were designed and synthesized. Their inhibitory activity against PD-1/PD-L1 interaction was evaluated by a homogeneous time-resolved fluorescence (HTRF) assay. Among them, LLW-018 (27c) exhibited the most potent inhibitory activity with an IC50 value of 2.61 nM. The cellular level assays demonstrated that LLW-018 exhibited low cytotoxicity against Jurkat T and MDA-MB-231. Further cell-based PD-1/PD-L1 blockade bioassays based on PD-1 NFAT-Luc Jurkat cells and PD-L1 TCR Activator CHO cells indicated that LLW-018 could interrupt PD-1/PD-L1 interaction with an IC50 value of 0.88 μM. Multi-computational methods, including molecular docking, molecular dynamics, MM/GBSA, MM/PBSA, Metadynamics, and QM/MM MD were utilized on PD-L1 dimer complexes, which revealed the binding modes and dissociation process of LLW-018 and C2-symmetric small molecule inhibitor LCH1307. These results suggested that LLW-018 exhibited promising potency as a PD-1/PD-L1 inhibitor for further investigation.
摘要：
阻断程序性细胞死亡-1（PD-1）/程序性细胞死亡配体1（PD-L1）途径是一种有吸引力的免疫治疗策略，但小分子PD-1/PD-L1抑制剂的临床应用尚不清楚。在这项工作中,基于BMS-202和我们先前的工作YLW-106，设计并合成了一系列以苯并[d]异噻唑结构为支架的化合物。通过均相时间分辨荧光（HTRF）测定法评估了它们对PD-1/PD-L1相互作用的抑制活性。其中,LLW-018(27c)表现出最有效的抑制活性,IC50值为2.61nM。细胞水平测定表明LLW-018表现出对JurkatT和MDA-MB-231的低细胞毒性。基于PD-1NFAT-LucJurkat细胞和PD-L1TCR激活剂CHO细胞的进一步基于细胞的PD-1/PD-L1阻断生物测定表明，LLW-018可以中断PD-1/PD-L1相互作用，IC50值为0.88μM。多种计算方法，包括分子对接，分子动力学,MM/GBSA,MM/PBSA,元动力学，和QM/MMMD用于PD-L1二聚体复合物，这揭示了LLW-018和C2对称小分子抑制剂LCH1307的结合模式和解离过程。这些结果表明，LLW-018作为PD-1/PD-L1抑制剂表现出有希望的效力，用于进一步研究。
