通过失活谷胱甘肽过氧化物酶4（GPX4）诱导细胞铁死亡是一种流行的癌症治疗策略。然而，目前只开发出了少数GPX4抑制剂。PROteolytic Targeting Chimera（PROTAC）是一种有希望的方法，提供了克服传统治疗局限性的新机会。在此，利用Ugi反应首次组装出类PROTAC的活性探针PD-Q2，包含已知的GPX4抑制剂ML-162同源物与E3连接酶脑纹状体蛋白配体泊马利多米德。拉取和免疫印迹分析表明，GPX4是PD-Q2的共价靶标，但降解效率较低。因此，通过改变异功能PROTAC的连接物合成了一系列降解剂。在这些降解剂中，PD-4和PD-P2被发现能够通过泛素-蛋白酶体系统促进有效GPX4降解，引起脂质ROS积累。PD-4和PD-P2显示出强大的抑制集落形成和细胞生长的功效。此外，我们发现，随着泊马利多米德的加入，降解剂表现出高的荧光信号，大部分位于溶酶体内，这可能影响了抗细胞增殖的有效性。总体而言，我们提供了GPX4降解剂，进一步探索调节铁死亡的治疗潜力。Copyright © 2023 Elsevier Inc. All rights reserved.

Inducing cell ferroptosis by inactivating glutathione peroxidase 4 (GPX4) is a popular cancer treatment strategy. However, only few GPX4 inhibitors have been developed to date. PROteolysis Targeting Chimera (PROTAC) is a promising approach to provide new opportunities to overcome limitations of traditional therapeutics. Herein, a PROTAC-like activity-based probe PD-Q2 was first assembled using Ugi reaction, consisting of a known GPX4 inhibitor ML-162 homolog to the E3 ligase cereblon ligand-pomalidomide. Pull-down and immunoblotting analysis revealed that GPX4 was a covalent target of PD-Q2, but the degradation efficiency was weak. Therefore, a series of degraders was further synthesized by varying the linkers of heterofunctional PROTACs. Among these degraders, PD-4 and PD-P2 were found to promote effective GPX4 degradation via the ubiquitin-proteasome system and cause lipid ROS accumulation. PD-4 and PD-P2 showed potent inhibitory of colony formation and cell growth. Furthermore, we found that with pomalidomide, the degraders exhibit a high fluorescent signal that is mostly localized in the lysosome, which may affect the effectiveness of anti-cell proliferation. Overall, we provide GPX4 degraders for further exploring therapeutic potential of regulating ferroptosis.Copyright © 2023 Elsevier Inc. All rights reserved.