半夏泻心汤通过Akt/c-Myc信号轴对胃癌外泌体诱导骨髓间充质干细胞PD-L1表达的影响OA

Objective:To observe how Banxia Xiexintang affects programmed cell death 1 ligand 1(PD-L1)expression induced by exosomes derived from gastric cancer cells in bone marrow mesenchymal stem cells(BMSCs)through the protein kinase B(Akt)/c-myelocytomatosis oncogene(c-Myc)signaling axis,and its effects on the migration of BMSCs and gastric cancer cells.Methods:Exosomes were isolated from human gastric cancer NCI-N87 cells and identified by transmission electron microscopy and Western blot.Rat BMSCs were passaged and identified by immunofluorescence staining.A Transwell chamber was used to create a non-contact co-culture system for NCI-N87 exosomes and BMSCs.The experiment was designed with normal,model,Banxia Xiexintang(10%serum containing Banxia Xiexintang),PD-L1 monoclonal antibody(10%blank serum containing PD-L1 antibody),and combination(10%serum containing Banxia Xiexintang and 10%blank serum containing PD-L1 antibody)groups.The suspension of BMSCs was added to the upper chamber of each group,with the normal group receiving serum culture medium without exosomes in the lower chamber,and the model group receiving NCI-N87 exosomes.The Banxia Xiexintang group,PD-L1 monoclonal antibody group,and combination group received 10%serum containing Banxia Xiexintang,10%blank serum containing PD-L1 monoclonal antibody,and 10%serum containing Banxia Xiexintang and 10%blank serum containing PD-L1 antibody,respectively,in the upper chamber.After 96 h,BMSCs from the upper chamber were collected,and the protein levels of p-Akt,Akt,c-Myc,and PD-L1,as well as the mRNA levels of Akt,c-Myc,and PD-L1,were determined by Western blot and Real-time PCR,respectively.The migration of BMSCs and NCI-N87 was assessed by the Transwell method.Results:Compared with the normal group,the model group showed increases in protein levels of p-Akt,c-Myc,and PD-L1,as well as mRNA levels of c-Myc and PD-L1(P<0.05,P<0.01),and no significant change in the protein and mRNA levels of Akt.Compared with the model group,the Banxia Xiexintang group,PD-L1 monoclonal antibody group,and combination group showed decreases in protein levels of p-Akt,c-Myc,and PD-L1(P<0.01).In addition,they had significant effects on the protein and mRNA levels of Akt.The combination group showed greater reductions in the protein and mRNA levels of c-Myc and PD-L1 than the Banxia Xiexintang group and PD-L1 monoclonal antibody group(P<0.05).Compared with the normal group,the model group showed increases in the number of migrating NCI-N87 and BMSCs(P<0.05,P<0.01).Compared with the model group,the Banxia Xiexintang group,PD-L1 monoclonal antibody group,and combination group showed decreases in the number of migrating NCI-N87 and BMSCs(P<0.05,P<0.01),with the combination group showing greater reductions in the number of migrating NCI-N87 and BMSCs than the Banxia Xiexintang group and PD-L1 monoclonal antibody group(P<0.01).Conclusion:Banxia Xiexintang can lower the PD-L1 expression induced by gastric cancer cell-derived exosomes in BMSCs induced and inhibit the migration of BMSCs and gastric cancer cells.Moreover,it has a synergistic effect when being used together with PD-L1,possibly related to the regulation of the Akt/c-Myc signaling axis.