肿瘤相关巨噬细胞中程序性死亡受体配体1的表达及其与乳腺癌不良预后的关系

Expression of programmed cell death-ligand 1 of tumor-associated macrophages and its relationship with adverse prognosis of breast cancer

目的探讨肿瘤相关巨噬细胞(TAMs)中程序性死亡受体配体1(PD-L1)的表达及其与乳腺癌不良预后的关系。方法通过单细胞RNA测序(scRNA-seq)数据库、肿瘤微环境单细胞转录组学数据库(TISCH)数据集分析165例乳腺癌患者免疫细胞中PD-L1的表达。采用多色免疫荧光法检测PD-L1在乳腺癌TAMs中的表达。诱导THP-1单核细胞至M2型极化,并与乳腺癌细胞系MCF-7和MDA-MB-231共培养24 h;通过蛋白质印迹(Western blot)和逆转录聚合酶链式反应(RT-PCR)检测TAMs中的PD-L1表达。结果与原发性乳腺癌相比,转移癌TAMs中PD-L1表达上调,差异有统计学意义(P<0.05)。TAMs中PD-L1表达与乳腺癌组织学分级呈正相关(P=0.001),与年龄、肿瘤直径、淋巴结转移、分子亚型和远处转移无相关性(P>0.05)。高密度PD-L1^(+)TAMs浸润提示预后不良。M2型巨噬细胞与MCF-7或MDA-MB-231细胞系共培养后,TAMs中PD-L1 mRNA及PD-L1蛋白表达水平增高。结论乳腺癌组织TAMs中PD-L1的表达与乳腺癌患者的组织学分级和不良预后显著正相关,且乳腺癌细胞可刺激M2型巨噬细胞(TAMs的主要成分)的PD-L1表达。

Objective To explore the expression of programmed cell death-ligand 1(PD-L1)of tumor-associated macrophages(TAMs)and its relationship with adverse prognosis of breast cancer.Methods The expression of PD-L1 in immune cells of 165 breast cancer patients was analyzed by single-cell RNA-sequencing(scRNA-seq)database and tumor immune single-cell hub(TISCH)dataset.Multicolor immunofluorescence was used to detect the expression of PD-L1 in breast cancer TAMs.THP-1 monocytes were induced to m2-type polarization and co-cultured with breast cancer cell lines MCF-7 and MDA-MB-231 for 24 h;the expression of PD-L1 in TAMs was detected by western blot and reverse transcription-polymerase chain reaction(RT-PCR).Results PD-L1 expression was significantly upregulated in metastatic TAMs compared with primary breast cancer(P<0.05).The expression of PD-L1 in TAMs was positively correlated with the histological grade of breast cancer(P=0.001),but had no correlation with the patient's age,tumor size,lymph node metastasis,molecular subtype and distant metastasis(P>0.05).High density PD-L1^(+)TAMs infiltration suggested a poor prognosis.When M2-type macrophages were co-cultured with MCf-7 or MDA-MB-231 cell lines,the expression levels of PD-L1 mRNA and PD-L1 protein in TAMs increased.Conclusion The PD-L1 expression in breast cancer tissue TAMs is significantly positively correlated with histological grade and poor prognosis of breast cancer patients,and breast cancer cells can stimulate PD-L1 expression in M2-type macrophages(the main component of TAMs).