McMichael Elizabeth L, Courtney Nicholas B, Duggan Megan C, Wesolowski Robert, Quiroga Dionisia, Kondadasula Sri Vidya, Atwal Lakhvir S, Bhave Neela, Luedke Eric, Jaime-Ramirez Alena Cristina, Campbell Amanda R, Mo Xiaokui, Byrd John C, Carson Iii William E
Biomedical Sciences Graduate Program, College of Medicine, Columbus, OH, US.
Comprehensive Cancer Center, Columbus, OH, USA.
Oncoimmunology. 2017 May 2;6(5):e1312045. doi: 10.1080/2162402X.2017.1312045. eCollection 2017.
Natural killer (NK) cells are innate immune effector cells that play a crucial role in immune surveillance and the destruction of cancer cells. NK cells express a low-affinity receptor for the Fc or constant region of immunoglobulin G (FcγRIIIa) and multiple cytokine receptors that respond to antibody-coated targets and cytokines in the tumor microenvironment. In the present work, microarray gene expression analysis revealed that the IL-21 receptor (IL-21R) was strongly upregulated following FcR stimulation. The IL-21R was found to be upregulated on FcR-stimulated NK cells at the transcript level as determined by reverse transcription polymerase chain reaction (RT-PCR). Immunoblot analysis revealed that protein expression of the IL-21R peaked at 8 h post-stimulation of the FcR. Inhibition of the mitogen-activated protein kinase (MAPK) pathway downstream of the FcR blocked the induction of IL-21R expression. Increased expression of the IL-21R sensitized NK cells to IL-21 stimulation, as treatment of FcR-stimulated NK cells led to significantly increased phosphorylation of STAT1 and STAT3, as measured by intracellular flow cytometry and immunoblot analysis. Following FcR-stimulation, IL-21-activated NK cells were better able to mediate the lysis of trastuzumab-coated human epidermal growth factor receptor 2 (HER2) SK-BR-3 tumor cells as compared to control-treated cells. Likewise, IL-21-induced NK cell secretion of IFNγ following exposure to antibody-coated tumor cells was enhanced following FcR-stimulation. The analysis of NK cells from patients receiving trastuzumab therapy for HER2 cancer exhibited increased levels of the IL-21R following the administration of antibody suggesting that the presence of monoclonal antibody-coated tumor cells can stimulate the increased expression of IL-21R on NK cells.
自然杀伤（NK）细胞是先天性免疫效应细胞，在免疫监视和癌细胞破坏中发挥关键作用。NK细胞表达免疫球蛋白G（FcγRIIIa）的Fc或恒定区的低亲和力受体以及多种细胞因子受体，这些受体可对肿瘤微环境中抗体包被的靶标和细胞因子作出反应。在本研究中，微阵列基因表达分析显示，FcR刺激后白细胞介素21受体（IL-21R）强烈上调。通过逆转录聚合酶链反应（RT-PCR）确定，在转录水平上，FcR刺激的NK细胞上的IL-21R被上调。免疫印迹分析显示，FcR刺激后8小时，IL-21R的蛋白表达达到峰值。抑制FcR下游的丝裂原活化蛋白激酶（MAPK）途径可阻断IL-21R表达的诱导。IL-21R表达的增加使NK细胞对IL-21刺激敏感，因为通过细胞内流式细胞术和免疫印迹分析测量，FcR刺激的NK细胞处理导致STAT1和STAT3的磷酸化显著增加。与对照处理的细胞相比，FcR刺激后，IL-21激活的NK细胞更能介导曲妥珠单抗包被的人表皮生长因子受体2（HER2）SK-BR-3肿瘤细胞的裂解。同样，在暴露于抗体包被的肿瘤细胞后，FcR刺激增强了IL-21诱导的NK细胞IFNγ的分泌。对接受曲妥珠单抗治疗HER2癌症患者的NK细胞分析显示，抗体给药后IL-21R水平升高，这表明单克隆抗体包被的肿瘤细胞的存在可刺激NK细胞上IL-21R表达增加。
