Ginsenoside (20)S-APPT induces ferroptosis in hepatocellular carcinoma and cholangiocarcinoma by targeting FSP1.

Triggering ferroptosis has recently been recognized as a promising approach for cancer treatment. However, current ferroptosis inducers, such as glutathione peroxidase 4 (GPX4) inhibitors, face limitations in terms of druggability and safety. In this study, we performed a phenotypic screen of a 180-compound natural product library and identified (20S)-protopanaxatriol ((20)S-APPT), a ginsenoside derivative, as a potent ferroptosis inducer with a favorable safety profile both in vitro and in vivo. We demonstrated that (20)S-APPT induced ferroptosis by targeting the plasma membrane-localized CoQ oxidoreductase FSP1. FSP1 inhibition promoted ACSL4-dependent arachidonic acid oxidation and mitochondrial ROS production, thereby increasing ferroptosis. Intriguingly, we revealed that FSP1 inhibition alone was sufficient to trigger ferroptosis in a subset of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) cells. Furthermore, the combined inhibition of FSP1 and γ-glutamylcysteine synthetase (GCS) synergistically induced ferroptosis in otherwise resistant cancer cells while sparing noncancerous cells. These results establish a previously unrecognized role for FSP1 in driving ferroptosis and highlight the therapeutic potential of cotargeting FSP1 and GCS in HCC and CCA.