南方医科大学学报

南方医科大学学报 ›› 2018, Vol. 38 ›› Issue (05): 561-.

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阻断乳腺癌细胞PD-L1减弱对共培养树突状细胞成熟的抑制作用

于晓然，温桥生，肖漪，唐芮，李福喜，邵文凤，余焱林，熊静波   

  • 出版日期:2018-05-20 发布日期:2018-05-20

Blocking programmed death-ligand 1 attenuates maturation inhibition of dendritic cells by co-cultured breast cancer cells

  • Online:2018-05-20 Published:2018-05-20

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摘要： 目的探讨表达PD-L1的乳腺癌细胞是否通过激活树突状细胞的PD-L1/PD-1信号通路抑制树突状细胞成熟。方法人单 核细胞用GM-CSF和IL-4诱导为不成熟树状突细胞，再用TNF-α诱导为成熟树状突细胞；表达PD-L1的乳腺癌细胞系MDAMB- 231与树状突细胞接触共培养；PD-L1阻断抗体处理共培的的乳腺癌细胞和树状突细胞；重组人PD-L1蛋白处理TNF-α诱 导的树突状细胞；流式细胞仪检测乳腺癌细胞膜PD-L1的表达和树突状细胞的成熟分化标志HLA-DR和CD83。结果乳腺癌 细胞MDA-MB-231细胞系中，细胞膜表面PD-L1阳性细胞高达（99.7±0.15）%；HLA-DR和CD83阳性细胞在成熟树状突细胞对 照组分别为（88.8±6.96）%和（18.36±3.07）%，在MDA-MB-231共培养实验组树状突细胞群分别降至（42.76±10.52）%和（9.93± 2.74）%，两组比较差异有统计学意义（P<0.01，P<0.05）；HLA-DR和CD83 阳性细胞在PD-L1 抗体同型对照组分别为（45.17± 10.19）%和（10.15±2.54）%，在PD-L1抗体处理组分别升至（63.46±1.72）%和（16.46±2.58）%，两组相比差异均有统计学意义（P< 0.05）；和成熟树状突细胞对照组相比，人重组PD-L1蛋白处理组HLA-DR和CD83阳性细胞率较低，组间统计学差异有统计学 意义（P<0.05）。结论PD-L1抗体对三阴性乳腺癌患者的治疗的效果，可能部分基于抗体阻断乳腺癌细胞表面的PD-L1，从而 减弱其对肿瘤微环境中的树突状细胞成熟的抑制作用。

Abstract: Objective To study if programmed death- ligand 1 (PL-L1) expression in breast cancer cell activates PD-L1/PD- 1 pathway in dendritic cells to inhibit dendritic cell maturation. Methods Human monocytes were induced to differentiate into immature dendritic cells using GM-CSF and IL-4, and further to mature dendritic cells using TNF-α. PD-L1-expressing breast cancer cell line MDA-MB-231 was co-cultured in contact with the dendritic cells to observe the effects of the breast cancer cells on the maturation of the dendritic cells. A PD-L1 blocking antibody was applied to the co- culture, and the changes in the inhibitory effect of the MDA-MB-231 cells on dendritic cell maturation was observed. TNF- α- induced dendritic cells were treated with a recombinant human PD-L1 protein to study the effect of PD-L1/PD-1 pathway activation on the maturation of dendritic cells. The expression of PD-L1 in MDA-MB-231 cells and the dendritic cell maturation marker HLA-DR and CD83 were analyzed using flow cytometry. Results MDA-MB-231 cell line showed PD-L1 positivity on the cell membrane cells at a rate as high as (99.7±0.15)%. In mature dendritic cells, the positivity rates for HLA-DR and CD83 were (88.8±6.96)% and (18.36± 3.07)% , respectively, but in the co-culture system, the positivity rates of the dendritic cells were significantly decreased to (42.76±10.52)% (P<0.01) and (9.93±2.74)% (P<0.05), respectively, indicating that MDA-MB-231 cells inhibited the maturation of dendritic cells. Following treatment with a PD-L1 antibody isotype control, the percentages of HLA-DR- and CD83-positive cells in the co-culture were (45.17±10.19)% and (10.15±2.54)%, which were significantly increased to (63.46±1.72)% and (16.46± 2.58)% after treatment with PD-L1 antibody, respectively (both P<0.05). Compared with the mature dendritic cell controls, the cells treated with the recombinant human PD- L1 protein exhibited significantly lowered percentages of HLA- DR- positive [from (84.23±4.18)% to (2.56±2.39)%, P<0.05] and CD83-positive cells [(87.26±1.54)% to (60.67±1.63)%, P<0.05]. Conclusion The effect of PD-L1 antibody therapy on triple negative breast cancer can be partially mediated by blocking PD-L1 expression on breast cancer cell membrane, which attenuates the inhibition of dendritic cell maturation in the cancer microenvironment.