Mechanism Of Artemisinin Induced Ferroptosis In T-cell Lymphoma And Blocking Immunosuppressive Function By Targeting MDSCs

ObjectiveArtemisinin（ART） and its derivatives are a class of sesquiterpene lactones containing peroxy group,which have become the first choice of antimalarial drugs generally recognized and put into use in the international community^[1].In recent years,it has been found that artemisinin and its derivatives not only have magical antimalarial effects,but also have anti-tumor and immunomodulatory effects.It has been reported that artemisinin is considered to be an effective anti lymphoma drug in the treatment of B-cell lymphoma and myeloid leukemia^[2,3],but the anti-tumor mechanism in the formation of T-lymphoma is not very clear.In addition,there are a group of myeloid derived suppressor cells（MDSCs）in the tumor microenvironment（TME）.Whether artemisinin can reverse its immunosuppressive state remains to be further explored.Therefore,the mechanism of Artemisinin induced ferroptosis and targeting MDSC immunosuppressive function in T-cell lymphoma is elaborated in this paper.MethodsIn the experiment of artemisinin induced feootptosis of T lymphoma,the apoptosis of tumor cells EL4 and Jurkat was detected under different Artemisinin concentrations and treatment time,and the apoptosis and reactive oxygen species（ROS）of tumor cells were detected after combined with iron inhibitor（DFO）,The level of ROS and the content of glutathione（GSH）in cells were measured;Western blot was used to detect the expression of AKT/m TOR/p70 signaling pathway and MAPK signaling pathway,as well as the expression of ubiquitin protein K48 Poly Ubi;The effect of Artemisinin was verified in mice.In order to study the immunosuppressive function of Artemisinin targeting MDSCs,MDSCs were isolated from mouse bone marrow in vitro and treated with different concentrations of Artemisinin.Compared with the control group,the proportion of MDSCs treated with different concentrations was detected;MDSCs were isolated from tumor and spleen of tumor bearing mice,and the proportion of immune cells was detected by flow cytometry;In vitro tumor model was used to detect the effect of Artemisinin treatment on the release of MDSCs from tumor supernatantThe effect of cell inhibition;The target genes were screened by rnaseq differential gene expression profile;In vivo,Artemisinin can enhance the anti-PD-L1 immunotherapy by targeting MDSCs.ResultsThe apoptosis of EL4 and Jurkat cells was dose-dependent and time-dependent,and Artemisinin could up regulate the ROS level of EL4 and Jurkat cells,down regulate the AKT/m TOR/p70 signaling pathway and up regulate the expression of MAPK signaling pathway.Artemisinin can also inhibit the content of GSH in tumor cells,destroy the antioxidant balance in tumor cells,and increase the expression of misfolded protein in tumor cells.Artemisinin can inhibit the growth of tumor in vivo,and the above effects of artemisinin can be inhibited by DFO.In tumor microenvironment,Artemisinin can reduce the aggregation and immunosuppressive function of MDSCs in tumor models in vivo and in vitro,and relieve the immunosuppressive effect of MDSCs on effector T cells.Artemisinin can also down regulate the main immunosuppressive protein ARG1 of MDSCs.In vivo experiments,Artemisinin inhibited tumor growth,combined with anti-PD-L1 antibody to enhance anti-PD-L1 immunotherapy.ConclusionsArtemisinin induced ferroptosis in T-cell lymphoma.Artemisinin can also target the immunosuppressive state of MDSCs and improve the effect of anti-PD-L1 immunotherapy.