3,6-Epidioxy-1,10-bisaboladiene induces ferroptosis-like cell death through lipid peroxidation

Abstract

3,6-Epidioxy-1,10-bisaboladiene (EDBD) is a bisabolane sesquiterpene endoperoxide that was isolated from an edible wild plant in Japan, Cacalia delphiniifolia. It showed partially apoptotic cell death through caspase activation against HL-60 cells. However, almost all of the cells had necrotic morphology. Thus, we examined the mechanism of action of EDBD on necrotic cell death. EDBD induced ferrous ion-dependent cell death which causes cell membrane damage, and its cell death form was like H₂O₂-induced necrosis in HL-60 cells. The oxidative stress-induced necrosis inhibitor IM-54 prevented EDBD-induced cell death, but it was not blocked by either caspase inhibitor, z-VAD-fmk, or necroptosis inhibitor, necrostatin-1. Furthermore, EDBD induced lipid peroxidation in a time- and dose-dependent manner and was inhibited with both ferrostatin-1 and α-tocopherol. EDBD also downregulated GPX4, the primary cell defense protein against lipid peroxidation, and decreased GSH levels. Taken together, these results suggest that EDBD induces ferrous ion-dependent ferroptosis-like cell death through lipid peroxidation.

Graphical Abstract

Highlights

• EDBD induces cell death accompanied by cell membrane damage.

• EDBD caused lipid peroxidation against HL-60 cells and cell death is suppressed by inhibitors of lipid peroxidation.

• EDBD-induced lipid peroxidation was potentiated by adding ferrous ions and relieved by adding iron chelators or inhibitors of lipid peroxidation.

• EDBD downregulated the protein expression of GPX4 and decreased intracellular GSH levels.

• Overall, EDBD-induced cell death is characterized as ferroptosis-like cell death.

Keywords:

• Endoperoxide
• lipid peroxidation
• ferroptosis

Acknowledgments

We are grateful to Emeritus Professor Don R Phillips of La Trobe University for the critical reading of this manuscript.

Authors’ contribution

N.U. wrote the manuscript, performed the experiments, and analyzed data; Y.T. and M.M. performed the experiments and analyzed data. S.U. H.O. and K.K. designed the methodology and conducted the research; K.K. performed critical revision and edited the manuscript. All authors reviewed and approved the final manuscript.

Disclosure statement

No potential conflict of interest is reported by the authors.

Additional information

Funding

This work was financially supported in part by the United Graduate School of Agricultural Sciences, Iwate University (IWATE UGAS).