Realgar-induced KRAS mutation lung cancer cell death via KRAS/Raf/MAPK mediates ferroptosis

KRAS is a biomarker for non-small cell lung cancer-targeted therapy, but there is currently no effective KRAS-targeting medication. Realgar is an impelling anti-cancer drug, however its significance in KRAS mutant lung cancer is uncertain. According to our findings, the IC(50) of H23 (KRAS mutant) cells is 2.99 times lower than that of H1650 (non-KRAS mutant) cells. Flow cytometry and the Hoechst 33258 staining assay revealed that H1650 cells treated with 4 µg/ml realgar had an apoptotic rate of 8.2%, while H23 cells had a rate of 21.46%. Accordingly, realgar was more sensitive to KRAS mutant cells. Transcriptome sequencing test indicated that there were 481 different expression genes in H23 cells treated with realgar. In H23 cells treated with realgar, mitochondria shrank, inner membrane folding was disturbed, and mitochondrial membrane potential crushed. Realgar boosted intracellular Fe(2+), reactive oxygen species, malondialdehyde and glutathione levels, which were all reversed by ferroptosis inhibitor Fer-1. Realgar decreased phosphorylated p-Raf, p-ERK1/2 and increased p-p38 and p-JNK, whereas only p-Raf was abolished by Fer-1. Raf inhibitor Sorafenib accelerated the realgar-induced ferroptosis. On H23 cells treated with realgar, the expression of GPX4, SCL7A11 decreased while ACSL4 expression increased; this effect could also be amplified by Sorafenib. In conclusion, the present study indicated that realgar may induce ferroptosis by regulating the Raf, and hence plays a role in anti-KRAS mutant lung cancer.