Elemene Enhances The Sensitivity Of Lung Cancer Cells To Cisplatin Chemotherapy By Inducing Pyroptosis

BackgroundsLung cancer,which includes non-small cell lung cancer(NSCLC)and small cell lung cancer(SCLC),is one of the most commonly diagnosed cancers and remains the leading cause of cancer-related death worldwide.85% of the cases of lung cancer are NSCLCs.Combination chemotherapy with platinum-based drugs,especially cisplatin is the first-line treatment for lung cancer in clinic.However,such treatments have serious side effects and are prone to induce drug resistance.Therefore,elevating the sensitivity of non-small cell lung cancer to cisplatin is of great clinical significance for the treatment of advanced lung cancer.Elemene(elemene)lipsome is an effective anti-tumor drug extracted from the traditional Chinese medicine Curcuma wenyujin.Elemene by Professor Xie Tian’s team.Both elemene and cisplatin can induce tumor cell-death with various mechanisms.Cisplatin can induce cell pyroptosis,and pyroptosis,as a special type of cell death,probably is closely related to elevating the sensitivity of chemotherapeutics on tumor cells.Therefore,the aim of this study is to investigate the effect of elemene on the sensitivity of cisplatin on non-small cell lung cancer,and to further explore the effect of elemene on pyroptosis.Our results will provide underlying theoretical basis for discovering new therapeutic treatments on non-small cell lung cancer.MethodsFirst,the MTT method was used to detect cell vitality and the release of lactate dehydrogenase(LDH)in the cell supernatant was tested by special kit.Western Blot was used to detect the pyroptosis marker proteins Gasdermin E(GSDME),Gasdermin D(GSDMD),Annexin V/PI double staining was used to detect cell death to explore the effect of elemene on the sensitivity of cisplatin to lung cancer cells A549 and the effect of elemene and cisplatin combining treatment on A549 cell-pyroptosis.Then,flow cytometry was used to detect the reactive oxygen species(ROS)in A549 cells after treatment with elemene and cisplatin.Second,cells treated by elemene and cisplatin were treated by reactive oxygen inhibitors Glutathione(GSH)or N-acetyl-L-cysteine(NAC),then the cell vitality,LDH release were detected.The cell death were tested by Annexin V/PI double staining and pyroptosis marker protein expression were tested by Western-blot to confirm that elemene promotes A549 cell pyroptosis by up-regulating ROS.Furthermore,caspase inhibitor z-VAD(Cell permeable pan caspase inhibitor)was used to block the activation of caspase-3,and cell proliferation,lactate dehydrogenase release,cell-death and pyroptosis marker protein expression were detected to further elaborate the specific mechanism of elemene–induced cell pyroptosis.Finally,A549 cells were injected subcutaneously into the right shoulder of nude mice to construct a nude mouse tumor model to verify the effects of elemene on enhancing the sensitivity of A549 cells to cisplatin chemotherapy in vivo.ResultsElemene enhanced the sensitivity of cisplatin on A549 cells and induced cell pyroptosis.Elemene induced cell-pyroptosis by promoting intracellular ROS and activating GSDMD,and by activating caspase-3,which in turn induced the cleavage of GSDME to enhance the sensitivity of cisplatin on A549 cells.Elemene promoted the sensitivity of cisplatin on tumor cells in vivo.ConclusionsElemene enhances the chemotherapy sensitivity of lung cancer cells to cisplatin through activating GSDMD by increase the production of reactive oxygen species,and through activating GSDME by inducing caspase-3 cleavage to induce pyroptosis.