Brusatol improves the efficacy of sorafenib in Huh7 cells via ferroptosis resistance dependent Nrf2 signaling pathway.

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis. The recommended treatment of unresectable HCC involves targeted therapy, for example sorafenib, combined with immunotherapy. A recent article reported that sorafenib could induce ferroptosis escape in HCC. Brusatol is a novel Nrf2 inhibitor that takes effects in various diseases. In our study, we aimed to identify whether the addition of Brusatol to sorafenib could reverse ferroptosis escape in Huh7 cells.

METHODS

The cultured Huh7 cells treated by sorafenib with or without Brusatol addition were harvested for ferroptotic phenotype experiments and ferroptosis-related markers such as GPX4 and SLC7A11 were detected. In vivo experiments were conducted to discover the effect of Brusatol in combination with sorafenib in liver tumor bearing mice. Mechanism signaling pathways were detected by RNA-sequencing.

RESULTS

Brusatol alone could induce Huh7 cell death and sorafenib could moderately mediate Huh7 cell ferroptosis by paradoxically inhibiting GPX4. However, sorafenib simultaneously upregulates Nrf2 signaling in Huh7 cells fighting against ferroptosis to result in sorafenib resistance. The addition of Brusatol could potentiate ferroptosis in Huh7 cells through downregulating Nrf2 and the downstream HO-1 and NQO1, thus enhancing the efficacy of sorafenib, which could be reversed by ferrostatin-1 treatment.

CONCLUSION

In conclusion, Brusatol improves the efficacy of sorafenib by inducing ferroptosis via hindering Nrf2 signaling activation in HCC.