Subtypes Of MDSCs Are Related To Gastric Cancer Prognosis And Are Inhibited By Epirubicin And Paclitaxel

Background and ObjectiveMyeloid-derived suppressor cells(MDSCs)is thought to play a critical immunosuppressive role in carcinogenesis.The incidence of gastric cancer is increasing.There are some reports that it has a certain connection with MDSCs.In this project,We aimed to explore the expression of MDSCs subgroup in peripheral blood of GC patients and the relationship between MDSCs subgroup and GC patients' total survival time;To explore the effect of epirubicin and paclitaxel on the percentage and function of bone marrow MDSCs in mice and the related mechanisms.Methods1? A total of 21 GC patients who had not previously received treatment were enrolled in this study from August 2014 to July 2016(15 males and 6 females;59 ± 13 years old)at the Second Affiliated Hospital of Zhengzhou University.EPI-or TAX-based chemotherapy was administered.Fifteen healthy controls from the Physical Examination Center of our hospital were included(11 males and 4 females;55.1 ± 10.35 years).EDTA blood was collected from the GC patients before and 2 weeks after the first cycle of chemotherapy treatment(before the second cycle chemotherapy).All samples were obtained with patients' informed consent.2? The two sides of the thigh bone were separated from the mice blunt,and the bone marrow was washed out and the bone marrow cells were extracted.Immunomagnetic beads were used to separate bone marrow MDSCs of mice with epirubicin(0,0.5,1,2 ?g/mL),paclitaxel(0,0.1,1 nM)to treat 24 h.3? Flow cytometry was used to detect the percentage of MDSCs subsets in GC peripheral blood(acceptance of epirubicin and paclitaxel scheme)and in mouse bone marrow(Pre and post treatment of epirubicin and paclitaxel).4 ? ELISA assay was used to detect the amount of Arg-1,iNOS and ROS released by MDSCs in bone marrow of mice treated with epirubicin and paclitaxel.5? Flow cytometry was used to detect the cell cycle distribution and apoptosis of bone marrow MDSCs in micetreated by epirubicin or paclitaxel.6 ? Western blot detected the expression of p-MAPK(ERK1/2),tMAPK(ERK1/2),p-NF-?B,and t-NF-?B protein in MDSCs treated by epirubicin(0,0.5,1,2 ?g/mL)or paclitaxel(0,0.1,1 nM).7 ? Statistical analyses were performed using SPSS17.0 software.When comparing two groups,statistical significance was determined using the 2-tailed Student's t-test.ANOVA was performed to compare more than two groups.The cutoff point of patient peripheral MDSCs was calculated with the Receiver operating characteristic(ROC)curve analysis and survival analysis was assessed using the Kaplan-Meier survival function.Averaged values are presented as the mean with SD,and P values < 0.05 were considered significant.Results1?MDSCs are elevated in GC patients and decrease after EPI-or TAX-based chemotherapy(25.29 ± 19.38% vs 6.15 ± 2.07%,P < 0.01),and the percentage of GMDSCs was higher than that of M-MDSCs(P < 0.01).The percentage of MDSCs subgroup decreased after receiving a cycle of chemotherapy with epirubicin and paclitaxel(P < 0.01).2?The high expression of G-MDSCs and M-MDSCs is associated with tumor differentiation in GC patients.The high expression of M-MDSCs is associated with lymph node metastasis(P < 0.05),and the high expression of M-MDSCs is negatively correlated with the overall survival time of gastric cancer patients(P < 0.05).3?Epirubicin and paclitaxel reduced the percentage of MDSCs subsets in mice bone marrow(P < 0.01).Epirubicin promoted MDSCs apoptosis and increased its percentage in G2/M phase(P < 0.01),and paclitaxel induced bone marrow MDSCs apoptosis(P < 0.01)in mice in vitro.4?Epirubicin can reduce the Arg-1 and iNOS produced by MDSCs(P < 0.05).TAX reduced the formation of Arg-1(P < 0.05),and no obvious abnormalities were found in ROS in vitro.5?Epirubicin reduced the Arg-1 and iNOS secretion of MDSCs from mouse bone marrow(P < 0.05),and paclitaxel only reduced the Arg-1(P < 0.05).Epirubicin and paclitaxel inhibited the expression of t-MAPK(ERK1/2),p-MAPK(ERK1/2)and t-NF-?B and p-NF-?B protein in MDSCs(P < 0.05)in vitro.Conclusions1?The percentage of MDSCs and their subsets in the peripheral blood of GC are elevated.Epirubicin and paclitaxel can reduce the percentage of MDSCs in peripheral blood of GC patients;The high expression of G-MDSCs and M-MDSCs is associated with the low differentiation of GC patients,and the high expression of MMDSCs is associated with lymph node metastasis.The percentage of M-MDSCs in peripheral blood of GC patients is related to the totel survival.2 ? Epirubicin and paclitaxel can inhibit the immunosuppressive function of MDSCs by inhibiting the release of Arg-1 and iNOS and the proliferation of MDSCs in bone marrow,and induce MDSCs apoptosis through MAPK(ERK1/2)and NF-?B signaling pathway.