Effect And Mechanisms Of PD-1/PD-L1 Expression On Nasopharyngeal Carcinoma

Objectives To investigate the tissue expression of programmed death 1(PD-1)and programmed death ligand 1(PD-L1)in Nasopharyngeal Carcinoma(NPC)and its possible regulatory effect and mechanism on NPC.Methods CNE-2Z human NPC cells tumor xenografts were established in nude mice.Mice were randomly divided into three groups(n = 5 mice).The first one was tumor control(TMC)group treated with saline injection,the second one was DHA group with injection of dihydroartemisinin(DHA),and the third one was BMS-202 group with injection of PD-1/PD-L1 inhibitor 2(BMS-202).The effects of DHA and BMS-202 on NPC were assessed by measuring tumor volume,tumor weight and hematoxylin-eosin staining of the excised tumors.The expression of PD-1/PD-L1 protein in the excised tumors was assessed by immunohistochemical staining.Results 1 The tumor volume in both DHA and BMS-202 groups was significantly reduced(P<0.05)in comparison with the counterpart in TMC group.The tumor volume in BMS-202 group was slightly more than that in DHA group but without statistically significant.2 At the end of the experiment(day 36th),the tumor weight in both DHA and BMS-202 groups was significantly reduced(P<0.05)in comparison with the counterpart in TMC group.The tumor weight in BMS-202 group was slightly more than that in DHA group but without statistically significant.3 The tumor inhibition rate in DHA and BMS-202 groups were 53.3%and 33.6%,respectively,and the difference among them was statistically significant.4 The expression of PD-1 and PD-L1 proteins of the excised tumors in both DHA and BMS-202 groups was significantly lower than the counterpart in TMC group(P<0.05),which indicated that the signaling pathways of PD-1 and PD-L1 proteins in NPC might be regulated by DHA and BMS-202.In BMS-202 group,there were slightly higher expression of PD-1 and PDL1 proteins compared with that in DHA group(P<0.05).5 Two cases of significant lung metastasis were observed in TMC group while no one in DHA and BMS-202 groups.In the two cases,the expression of PD-1 was higher than the expression of PD-L1 but without statistically significant.Conclusions 1 The drugs DHA and BMS-202 both could reduce the tumor volume and weight of NPC tumor-bearing,and regulate tumor growth with tumor inhibition rates of 53.3%and 33.6%,respectively.2 The drugs DHA and BMS-202 both could reduce the protein expression of PD-1/PD-L1 in NPC tumor-bearing,and might inhibit pulmonary metastases arising from NPC.