FTH promotes the proliferation and renders the HCC cells specifically resist to ferroptosis by maintaining iron homeostasis

Ferroptosis is a newly identified type of programmed cell death, which preferentially targets iron-rich cancer cells such as hepatocellular carcinoma (HCC). Ferritin heavy chain (FTH) is a major iron storing nanocage to store redox-inactive iron, and harbors ferroxidase activity to prevent the iron-mediated production of ROS. Our previous studies have demonstrated that FTH acts as a protective role to increase the cellular resistance to ferroptosis. However, the specific role of FTH in the development of HCC and ferroptosis resistance remains unclear.

These results provide new insights that FTH acts as an oncogene in the carcinogenesis and progression of HCC, and is hopeful to be a potential target for therapeutic intervention through ferroptosis.

The indicated databases were used for bioinformatics analysis. The abilities of cell proliferation, migration were measured by cell proliferation assay, transwell assay and wound healing assay. The levels of reactive oxygen species (ROS), lipid peroxide, free iron, mitochondrial superoxide, mitochondrial morphology and mitochondrial membrane potential (MMP) were determined by DCF-DA, C11-BODIPY, mitoSOX, mitoTracker, JC-10 and TMRM staining, respectively. The mitochondrial oxygen consumption rate was monitored by the Seahorse XF24 Analyzer.

The pan-cancer analysis was performed and showed that FTH expression is upregulated in multiple cancers, such as LIHC, CHOL, HNSC, compared to corresponding normal tissues. In addition, the level of serum ferritin is positively associated with the progression of hepatitis, cirrhosis liver and hepatocellular carcinoma. Further investigation shed light on the strong correlation between FTH expression and tumor grades, cancer stages and prognosis of HCC. Importantly, the proteins interaction network elucidated that FTH is involved in iron homeostasis maintenance and lysosomal-dependent degradation. Enforced expression of FTH accelerates proliferation, migration and endows HCC cells specifically resistant to ferroptosis, but does not protect against cell death caused by cytotoxic compounds like oxaliplatin, irinotecan, and adriamycin. Mechanically, FTH reconstituted cells exhibit diminished peroxides accumulation, reduce mitochondrial ROS level, attenuate the impaired mitochondrial respiratory and rescue the mitochondrial homeostasis. Notably, FTH expression boosts tumorigenic potential in vivo with increased PCNA staining and lesser lipid peroxides generation.