CIL56 is a small molecule that induces cellular ferroptosis through the production of iron-dependent reactive oxygen species (ROS). It also induces accumulation of long-chain saturated, monounsaturated, and polyunsaturated fatty acids in HT-1080 cells in vitro.HT-1080 cells lacking acetyl-CoA carboxylase 1 (ACC1), the rate-limiting enzyme in fatty acid synthesis, exhibit 5-fold resistance to CIL56 treatment, indicating ACC1 activity sensitizes cells to CIL56-induced cell death.