DeFer-2 is a ferritin PROTAC degrader (Kd= 17.1 μM). It triggers the degradation of ferritin leading to the accumulation of free iron ions and an increase in ROS, which subsequently initiates caspase 3-GSDME mediated pyroptosis in cancer cells. DeFer-2 significantly inhibits tumor growth and extends the survival of mice with subcutaneous B16F10 tumors, and it is useful for melanoma research.

DeFer-2 (0-5 μM, 0-24 hours) reduces ferritin expression by forming a ternary complex with ferritin and VHL, leading to disruption of redox and mitochondrial homeostasis in B16F10 cells. At 5 μM for 8-24 hours, DeFer-2 triggers caspase 3-GSDME-mediated pyroptosis in B16F10 cells via free iron accumulation and increased ROS levels. With exposure from 24-48 hours, DeFer-2 exhibits significant cytotoxicity in B16F10 cells, with IC50 values of 3.1 μM and 1.5 μM at 24 and 48 hours, respectively.

DeFer-2 (10 mg/kg, intravenous injection, once every other day, for a total of 8 days) can effectively inhibit the tumor proliferation in the B16F10 tumor mouse model and prolong their lifespan.