JIB-04 Regulates the MDM2/P53/SLC7A11/GPX4 Signaling Axis to Induce Ferroptosis in Hepatocellular Carcinoma Cells by Inhibiting KDM4C Expression
It has been reported that Jumonji histone demethylase inihibitor(JIB-04)inhibits the occur-rence and development of tumors,but the specific mechanism is still unclear.In this paper,hepatocellu-lar carcinoma cells HepG2 and Huh7 were used as the models,and the effect of JIB-04 on the prolifera-tion of hepatocellular carcinoma was explored and its mechanism was explained.CCK-8 assays and EDU staining assays showed that JIB-04 reduced the proliferation ability of HepG2 and Huh7 cells in a concen-tration-dependent manner,with the half-inhibitory concentrations being 0.7689 μmol/L and 0.7392μmol/L,respectively.Flow cytometry analysis showed that JIB-04 could significantly activate the accu-mulation of ROS in cells.The levels of intracellular GSH and lipid peroxide MDA were detected by gluta-thione(GSH)detection kit and lipid peroxide malondialdehyde(MDA)detection kit,respectively.It was found that under 2 μmol/L JIB-04 treatment,the intracellular GSH of HepG2 and Huh7 cells de-creased by 88.4%and 80.7%,respectively.Lipid peroxides increased 4.75-fold and 9.25-fold,respec-tively.qRT-PCR and Western blotting results showed that JIB-04 could significantly reduce the mRNA levels and protein levels of ferroptosis related factors GPX4 and SLC7A11,while ferroptosis related path-way protein MDM2 was significantly down-regulated and P53 protein was significantly up-regulated.Mechanistic analysis found that JIB-04 reduced histone demethylase KDM4C protein levels by about 58%and 51%.A chromatin immunoprecipitation assay showed that Tri-methylation level of histone H3 at ly-sine 9 at the promoter region of the MDM2 gene,was increased by 2.19-fold and 2.14-fold respectively in JIB-04 treated hepatocellular carcinoma cells.Meanwhile,qRT-PCR proved that MDM2 mRNA level was significantly down-regulated in hepatocellular carcinoma cells after JIB-04 treatment.In summary,this study initially reveals that JIB-04 could downregulate the expression of the specific demethylase KDM4C,and then affect the methylation level of H3K9me3 in the promoter region of MDM2 gene to in-hibit the expression of MDM2 gene,reduce MDM2 protein binding to P53 protein,upregulate P53 pro-tein expression and simultaneous downregulate ferroptosis related proteins SLC7A11 and GPX4.It leads to intracellular GSH depletion,ROS and lipid peroxide accumulation,and finally leads to ferroptosis of cells.