Quandt Dagmar, Jasinski-Bergner Simon, Müller Ulrike, Schulze Bianca, Seliger Barbara
Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Magdeburger Str, 2, Halle 06112, Germany.
J Transl Med. 2014 May 30;12:151. doi: 10.1186/1479-5876-12-151.
The importance of B7-H molecules for the T cell/tumor communication and its impact on renal cell carcinoma (RCC) progression and prognosis has been recently described. Cytokine treatment of RCC has earlier been shown to be beneficial in preclinical settings, but its clinical implementation has not proven to be as effective. This might be partially explained by the yet incomplete picture of cellular alterations in tumor cells upon cytokine treatment investigated in detail in this study.
RCC tumor cell lines were treated with different cytokines alone or in combination. The constitutive and/or cytokine-induced expression of cytokine receptors signaling components and B7-H molecules in RCC cells were analysed by qPCR and flow cytometry. A mcherry reporter gene construct containing B7-H1 promoter was cloned and its activity was determined upon transfection in cytokine-stimulated cells. Cytokine pretreated tumor cells were co-cultured with allogeneic CD8+ T cells from healthy donors and T cell proliferation as well as cytokine secretion was determined.
A heterogeneous, but constitutive B7-H1,-H2,-H3 and H4 expression was found on human RCC cell lines. IL-4 and TNFα treatment led to strong synergistic induction of B7-H1 in RCC cells, whereas B7-H2 was only increased by TNFα. In contrast, B7-H3 and B7-H4 expression were not altered by these cytokines. Treatment of RCC cells with TNFα and IL-4 was accompanied by an activation of signaling molecules like NF-κB, IκB and STAT6. The cytokine-mediated up-regulation of B7-H1 was due to transcriptional control as determined by an increased B7-H1 promoter activity in the presence of IL-4 and TNFα. Despite HLA class I and LFA-1 were also increased, the cytokine-mediated up-regulation of B7-H1 was more pronounced and caused an inhibition of allospecifc CD8+ T cell proliferation.
Thus, IL-4 and TNFα, which could be released by immune cells of the tumor microenvironment, are able to control the B7-H1 expression in RCC thereby altering T cell responses. These data are of importance for understanding the complex interplay of tumor cells with immune cells orchestrated by a number of different soluble and membrane bound mediators and for the implementation of check point antibodies directed against B7-H1.
最近已有研究阐述了B7-H分子在T细胞与肿瘤细胞通讯中的重要性及其对肾细胞癌（RCC）进展和预后的影响。此前研究表明，细胞因子治疗RCC在临床前研究中有益，但尚未证明其临床应用同样有效。本研究详细探究了细胞因子治疗后肿瘤细胞中的细胞改变情况，这或许能部分解释上述现象。
单独或联合使用不同细胞因子处理RCC肿瘤细胞系。通过qPCR和流式细胞术分析RCC细胞中细胞因子受体信号成分和B7-H分子的组成性和/或细胞因子诱导表达。克隆含有B7-H1启动子的mcherry报告基因构建体，并在细胞因子刺激的细胞中转染后测定其活性。将经细胞因子预处理的肿瘤细胞与来自健康供体的同种异体CD8+ T细胞共培养，测定T细胞增殖和细胞因子分泌情况。
在人RCC细胞系上发现了异质性但组成性的B7-H1、-H2、-H3和H4表达。IL-4和TNFα处理导致RCC细胞中B7-H1的强烈协同诱导，而B7-H2仅被TNFα上调。相比之下，这些细胞因子未改变B7-H3和B7-H4的表达。用TNFα和IL-4处理RCC细胞伴随着NF-κB、IκB和STAT6等信号分子的激活。细胞因子介导的B7-H1上调归因于转录控制，这是通过在存在IL-4和TNFα的情况下B7-H1启动子活性增加来确定的。尽管HLA I类分子和LFA-1也增加了，但细胞因子介导的B7-H1上调更为明显，并导致同种异体CD8+ T细胞增殖受到抑制。
因此，肿瘤微环境中的免疫细胞释放的IL-4和TNFα能够控制RCC中B7-H1的表达，从而改变T细胞反应。这些数据对于理解肿瘤细胞与免疫细胞之间由多种不同的可溶性和膜结合介质精心编排的复杂相互作用，以及对于实施针对B7-H1的检查点抗体具有重要意义。
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