Cooperative inhibition of mTORC1 disrupts iron-redox homeostasis and triggers ferritinophagy-dependent ferroptosis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) remains a leading cause of cancer mortality, and the clinical utility of β-lapachone (β-Lap) is limited by dose-dependent toxicity. Here, we identify cryptotanshinone (CPT), a bioactive compound derived from Salvia miltiorrhiza, as a synergistic partner that enables dose reduction while enhancing antitumor efficacy. Integrated transcriptomic profiling, biochemical analyses, target engagement assays, and in vivo validation support that β-Lap and CPT cooperatively induce ferroptosis through disruption of iron-redox homeostasis. Mechanistically, β-Lap and CPT engage Raptor and mTOR, respectively, in vitro, supporting a model wherein their cooperative action leads to dual suppression of mTORC1 signaling. mTORC1 inhibition activates NCOA4-mediated ferritinophagy, promoting ferritin degradation and expansion of the labile Fe2+ pool. The consequent iron-dependent Fenton reaction drives excessive reactive oxygen species (ROS) accumulation and lipid peroxidation, culminating in ferroptotic cell death. Notably, this process occurs without downregulation of the canonical GPX4-SLC7A11 axis, defining a non-canonical, iron-amplified ferroptosis pathway. In xenograft models, the combination therapy significantly suppressed tumor growth without detectable systemic toxicity and recapitulated the molecular hallmarks observed in vitro, including mTORC1 inhibition, enhanced ferritinophagy, iron overload, and lipid peroxidation. Collectively, our findings support cooperative mTORC1 inhibition as a strategy to trigger ferritinophagy-dependent iron-redox collapse and non-canonical ferroptosis, providing a mechanistically informed and low-toxicity therapeutic approach for HCC.