Activation of GSDME by Lithospermum erythrorhizon drives pyroptotic cell death

Objective: To reveal GSDME-executed pyroptosis in cancer cells induced by the Chinese traditional herbal medicine plant Lithospermum erythrorhizon (L. erythrorhizon, Zi Cao) and to investigate the potential mechanism. Methods: L. erythrorhizon was extracted by ultrasonication in 95% ethanol, and determined using high-performance liquid chromatography (HPLC). HeLa, A549, SW620, HEK-293 T, THP-1, K562, Raw264.7 and MDA-MB-231 cell lines were used to investigate the morphology and mechanism of pyroptosis induced by L. erythrorhizon. The lactate dehydrogenase (LDH) release, propidium iodide (PI)/Hoechst double-staining, and pyroptosis reconstitution experiments were performed to study L. erythrorhizon -induced cell pyroptosis. Results: Compared with the death inhibitor, PI/Hoechst and LDH release experiments, we found that L. erythrorhizon induced pyroptosis. Recombination and western blot experiments confired that L. erythrorhizon induced GSDME cleavage, which drives pyroptosis. This phenomenon is conserved in several cancer cell lines that might be triggered by caspase family proteases. The mechanism of L. erythrorhizon inducing pyroptosis is widely found in tumor cells. Conclusion: Our findings not only explain how L. erythrorhizon triggers cancer cell pyroptosis, but also provide mechanistic insights to guide its clinical application in the future.