Effects of Brucea javanica oil emulsion injection on the expression of PDL-1 and the sensitivity of PD-1 monoclonal antibody in lung adenocarcinoma tumor-bearing mice

YANG Wenjing; ZHANG Qian; LI Chunjiang; ZHOU Lihong; JIN Xin; MENG Deming; JIA Jiang

doi:10.13431/j.cnki.immunol.j.20240060

Abstract：The study was aimed to assess the impact of Brucea javanica oil emulsion(BJOE)on the responsiveness of programmed death receptor-1(PD-1)monoclonal antibody to lung adenocarcinoma in mice.The experimental approach involved subcutaneously inoculating Lewis's lung adenocarcinoma(LLC)cells into C57BL/6 mice,which were then divided into four groups:model group,25 ml·kg-1 BJOE group,10 mg·kg-1 PD-1 group,and combination group(25 ml·kg-1 BJOE and 10 mg·kg-1 PD-1).Tumor volume,mass,and inhibition rate were evaluated;the apoptosis within tumor tissue was detected by TUNEL staining;CD4+and CD8+T cell proportions within tumor tissues were analyzed by flow cytometry;the levels of tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ)and granzyme B in tumor tissue were measured by enzyme-linked immunosorbent assay(ELISA).Additionally,LLC cells were categorized into a control group and three BJOE treatment groups(10,30,50 μl·ml-1),and programmed death ligand 1(PD-L1)expression in tumor tissues and LLC cells were assessed by Western blotting.Data showed that as compared with the model group,PD-1 monoclonal antibody alone did not significantly alter tumor volume,tumor mass,CD4+and CD8+T cell proportions,cytokine levels(IFN-γ,TNF-α,Granzyme B),or apoptosis in lung cancer-bearing mice.However,BJOE treatment reduced tumor volume and mass,enhanced CD4+and CD8+T cell proportions,increased cytokine levels,and augmented apoptosis(all P<0.05).Furthermore,the combination therapy of BJOE and PD-1 monoclonal antibody yielded significantly greater reductions in tumor volume and mass,with heightened CD4+and CD8+T cell proportions,cytokine levels,and apoptosis compared to either treatment alone(all P<0.05).Both BJOE treatment and the combination therapy significantly upregulated PD-L1 protein expression in tumor tissues compared to the model or PD-1 monoclonal antibody groups(P<0.05).Similarly,BJOE treatment at all tested concentrations significantly increased PD-L1 protein expression in LLC cells as compared to the control group(P<0.05).In conclusion,BJOE could upregulate PD-L1 expression in LLC cells and enhance the sensitivity of lung adenocarcinoma-bearing mice to PD-1 monoclonal antibodies.