LXRs Agonist T0901317 Exerts Ferroptosis Sensitization In Cancer And Its Mechanism

OBJECTIVE: A growing number of studies have demonstrated that ferroptosis has anti-tumor effect on a variety of cancers.Meanwhile,ferroptosis serves as a novel way to deal with drug resistance and refractory tumors.How to enhance the sensitivity of cancer cells to ferroptosis has also become the focus of attention.METHODS: Cell viability assay(CCK-8)and colony formation assays were used to study the combination effect of T0901317 and ferroptosis agonist Erastin/RSL3 and the relationship between improving cytotoxicity and ferroptosis.Proportion of cells stained by propidium iodide was examined by flow cytometry,C11-BODIPY staining evaluated lipid peroxidation levels,detection of ferroptosis pathway-related protein changes via western blot,construction of GPX4 overexpressing cell line to further identify the role of GPX4 in drug combination,tumor-bearing model was used to verify the joint treatment effect in vivo.RESULTS: Cell viability assays and colony formation assays showed that T0901317 alone cannot induce ferroptosis,but T0901317 and ferroptosis inducers have the combined effect of inhibiting cancer cells,and this effect can be rescued by ferroptosis specific inhibitors.PI staining results also showed a higher proportion of dead cells in the combination group than in the single-agent group or that in the control group.C11-BODIPY staining showed that the combined group had higher lipid peroxidation levels than that in the single-agent group or that in the control group.In combined group,protein expression in GPX4 showed significantly decrease compared to the single-agent group and the control group.In GPX4 overexpressing H1299,the proportion of dead cells was significantly reduced compared with vector H1299.Further,xenograft model further confirmed the effect of the drug combination in vivo.CONCLUSION: T0901317 sensitizes cancer cells to ferroptosis via synergistically inhibiting GPX4.