Stress-induced vtRNA1-1 modulates redox homeostasis and ferroptosis susceptibility in hepatocellular carcinoma cells

Abstract

Ferroptosis is a unique form of regulated cell death characterized by iron-dependent lipid peroxidation. Although the molecular details of ferroptosis regulation have been widely explored, the contributions of short non-coding RNAs (ncRNAs) to ferroptosis regulation, other than miRNAs remain poorly understood. Here, we identified vault RNA1-1 (vtRNA1-1) as a previously unrecognized short ncRNA regulator of ferroptosis in hepatocellular carcinoma (HCC) cells. vtRNA1-1 expression was upregulated by ferroptosis inducers and exhibited strong negative correlation with ferroptosis sensitivity, thus protecting cells from ferroptosis. vtRNA1-1 levels were elevated in selected ferroptosis-resistant cells, while its depletion reversed the phenotype thus resensitizing these cells to ferroptosis. These findings suggested a contribution of vtRNA1-1 to both intrinsic and acquired ferroptosis resistance. Mechanistically, we uncovered that increased oxidative stress, which potentiates lipid peroxidation, specifically induced expression of the vtRNA1-1 paralog in an NF-{kappa}B dependent manner. Elevated vtRNA1-1 levels suppressed NF-{kappa}B-mediated pro-oxidant gene expression, thereby limiting reactive oxygen species (ROS) accumulation and alleviating oxidative stress. Taken together, oxidative stress-inducible vtRNA1-1 governs redox balance by forming a reciprocal regulatory loop with NF-{kappa}B and this loop determines ferroptosis susceptibility by adjusting basal ROS levels. Our findings provide unprecedented insights into the regulation of redox homeostasis in HCC cells mediated by a short ncRNA and uncovered vtRNA1-1 as a potential therapeutic target for overcoming ferroptosis resistance in liver cancer.