Ginseng-derived Nanoparticles Potentiate Immune Checkpoint Antibody Efficacy By Reprogramming The Cold Tumor Microenvironment

Background and objectiveAt present,tumor immunotherapy is on the cutting edge of clinical cancer treatment,and the immune check point inhibitors(ICIs),such as the programmed death 1(PD-1)mAb and the cytotoxic t lymphocyte-associated antigen 4(CTLA-4)mAb,have been approved by the U.S.food and drug administration(FDA)for the clinical treatment in multiple advanced tumors.However,the objective response rate(ORR)for ICIs therapy in tumor is less than 50%,so improving clinical immunotherapy efficacy is important.Many studies indicated that the "cold tumor" with low CD8+T cells Infiltration has little response to the PD-1 mAb treatment,and the patients with "hot tumor"may benefit the PD-1 mAb treatment in improving the prognosis and survival time.Nowadays,many kinds of Chinese medicines have been recognized with the role of improving immunity and anti-carcinogenesis.Ginseng contains a variety of active ingredients such as ginsenosides,sugars,vitamins,and amino acids,which have been certificated to enhance immunity.However,the material basis and treatment mechanism of fresh ginseng for immunity adjustment are urgently needed to be clarified.In our previous study,the ginseng-derived nanoparticles(GDNPs)can efficiently polarize M2-like macrophages to M1-like macrophages and inhibit the representative"hot tumor" progression when intraperitoneally injected into B16-F10 murine melanoma bearing mice.In this study,we explored whether GDNPs combined with PD-1 mAb could change the protumor environment to anti-tumor environment,initiated by polarizing M2-like to M1-like TAMs.The results demonstrated that,compared with T cells in the Vehicle group,more T cells were recruited to the tumor microenvironment(TME)by TAMs-derived chemokines with Combo treatment.This combinatorial therapy changed the TME from cold to hot and further enhanced the anti-tumor efficacy of PD-1 mAb.The objective of this research is to verify whether GDNPs combined with PD-1 mAb can inhibit the growth of murine cold tumors,inhibit metastasis of murine tumors,and inhibit tumor recurrence.Methods and resultsFirst,by using bioinformatics methods,the correlation between the gene CD206 and CD8a in COAD and TNBC were analyzed.The results showed that the transcript expression of the CD206 is negatively correlated with the CD8a in both tumor types,which indicated that macrophage polarization can increase the CD8+T lymphocytes percentages in tumor and may enhance the PD1 mAb treatment efficacy.Then.GDNPs and PD-1 mAb(the Combo)treatment strategy was performed in three murine tumor models(CT26 colon tumor,MC38 colon tumor and 4T1 breast tumor)and results showed that the Combo therapy could effectively inhibit the tumor growth.Besides,Combo treatment can effectively inhibit the 4T1 murine tumor lung metastasis,extend the lifespans of mice,and effectively prevent the tumor recurrence.Secondly,flowcytometry analysis was performed to detect the changes in TME of mice under Combo treatment.The results showed that the Combo treatment could effectively increase the percentage of CD8+T lymphocytes and Thl lymphocyte in the TME.Besides,the IFNγ+and TNFα+T lymphocytes increased which indicated the improved cytotoxic function of T lymphocytes.In the end,we analyzed the RNA-seq results of GDNPs treated M2-like macrophages in vitro,and performed the RT-PCR(real time polymerase chain reaction)and ELISA(enzyme linked immunosorbent assay)to verify the results of RNA-seq.Besides,the results in tumor also confirmed that GDNPS could promote M2-like macrophages to secrete CCL5 and CXCL9 in TME in vivo.ConclusionGDNPs can be used to polarize M2-like macrophage to M1-like macrophages,and to increase the production of CCL5 and CXCL9 which enhance the T lymphocytes infiltration in CT26 murine colon tumor.GDNPs could improve the TME of cold tumor and change the cold tumor to hot tumor.Innovation1.A new combinatorial immunotherapy strategy,GDNPs combined with PD-1 mAb,effectively inhibits cold tumor progression and helps to,improve the response rate of the cold tumor to the ICIs,and provides a new combinatorial treatment strategy for the future clinical immune treatment.2.Clarify the material basis of ginseng in anti-tumor immunotherapy.By taking advantage of interdisciplinary theories,we found a new material basis of fresh ginseng.