PROTACFSP1 degrader 1 is an effective and selective PROTAC degrader that targets FSP1. It significantly induces the accumulation of lipid peroxides within cells. Additionally, PROTACFSP1 degrader 1 works synergistically with GPX4 inhibitors to enhance ferroptosis. It increases the mRNA expression of ferroptosis-related proteins (GPX4, FTH1, ACSL4, TfR1, FSP1) and is instrumental in the study of triple-negative breast cancer.

PROTAC FSP1 degrader 1 (Compound 2307) effectively induces 83.2% degradation of FSP1 protein at concentrations ranging from 0 to 2 μM over a 24-hour period, with a DC50 of 263.7 nM and no hook effect, while showing a concentration-dependent degradation in MDA-MB-231 cells. Pre-treatment with MG132, Pevonedistat (MLN4924), and Pomalidomide significantly inhibits FSP1 degradation mediated by PROTAC FSP1 degrader 1 at 1 μM for 24 hours. When used alone at 0-100 μM for 24-48 hours, PROTAC FSP1 degrader 1 does not exhibit significant cytotoxicity on MDA-MB-231 cells, as cell viability remains largely unchanged; however, it synergistically enhances cell death when combined with the GPX4 inhibitor RSL3. At 10 μM for 24 hours, PROTAC FSP1 degrader 1 significantly reduces the proportion of EdU-positive cells and inhibits MDA-MB-231 cell proliferation. It also induces the accumulation of reactive oxygen species (ROS) in MDA-MB-231 cells, triggering lipid peroxidation and ferroptosis. Ferroptosis is further confirmed as Fer-1 reverses the lipid peroxidation induced by FSP1 degradation. Additionally, at 0.2-5 μM for 24 hours, PROTAC FSP1 degrader 1 upregulates the mRNA expression of ferroptosis-related genes GPX4, FTH1, ACSL4, TfR1, and FSP1 in MDA-MB-231 cells.