INTRODUCTION: Hepatocellular carcinoma (HCC) remains difficult to treat, highlighting the need for new therapeutic strategies. RTA-408 (omaveloxolone), a synthetic oleanane triterpenoid and NRF2 pathway modulator, has reported anticancer activity, but its mechanisms in HCC are not fully understood. MATERIALS AND METHODS: HepG2 and PLC/PRF/5 (PP5) cells were treated with RTA-408 for 24 h. Cell viability, apoptosis, and signaling pathways were evaluated using MTT assay, Annexin V/7-AAD flow cytometry, and western blotting. The role of p38 signaling was examined using the p38 inhibitor SB203580. RESULTS: RTA-408 reduced cell viability in a concentration-dependent manner and increased apoptosis in both cell lines. At 600 nM, apoptosis increased to approximately 18.43% in HepG2 cells and 24.71% in PP5 cells. RTA-408 increased p38 phosphorylation and NRF2 expression and was accompanied by LC3B and p62 accumulation and elevated cleaved caspase-3. Inhibition of p38 partially restored cell viability and reduced apoptosis. CONCLUSION: RTA-408 suppresses HCC cell survival through a p38-dependent stress response associated with NRF2 activation and LC3B/p62 accumulation.
Chen et al. (Mon,) studied this question.