白细胞介素(IL)-7信号通过CD127在癌症和慢性感染的淋巴细胞受损,导致CD8+T细胞耗尽。在黑素瘤中CD8+T细胞对IL-7应答的潜在机制仍未完全阐明。我们先前显示黑色素瘤患者的IL-7水平降低。因此,本研究的目的是研究IL-7调节对黑色素瘤中CD127表达和CD8+T细胞反应的影响.
纳入健康对照和原发性皮肤黑素瘤患者。通过流式细胞术确定CD8+T细胞上的膜结合CD127(mCD127)表达。通过ELISA测量可溶性CD127(sCD127)蛋白水平。通过实时PCR测量总CD127和sCD127mRNA水平。用重组人IL-7以及信号通路抑制剂刺激CD8+T细胞。CD8+T细胞与黑色素瘤细胞系共培养,通过检测乳酸脱氢酶的表达来评估CD8+T细胞的细胞毒性。
与对照组相比,黑素瘤患者的血浆sCD127较低。表达mCD127的CD8+T细胞的百分比较高,而黑色素瘤患者外周血和肿瘤浸润性CD8+T细胞中sCD127mRNA水平较低。CD8+T细胞中总CD127mRNA表达在各组间差异无统计学意义。IL-7刺激增强了CD8+T细胞的总CD127和sCD127mRNA表达和sCD127释放。然而,CD8+T细胞上的mCD127mRNA表达不受影响。该过程主要由磷脂酰肌醇3-激酶(PI3K)途径介导。来自黑素瘤患者的CD8+T细胞表现出降低的细胞毒性。IL-7刺激促进CD8+T细胞的细胞毒性,而抑制PI3K抑制IL-7诱导的CD8+T细胞的细胞毒性升高。
目前的数据表明,IL-7分泌不足可能导致原发性皮肤黑色素瘤患者的CD8+T细胞衰竭和CD127失调。
Interleukin (IL)-7 signaling through
CD127 is impaired in lymphocytes in cancers and chronic infections, resulting in CD8+ T cell exhaustion. The mechanisms underlying CD8+ T cell responses to IL-7 in melanoma remain not completely elucidated. We previously showed reduced IL-7 level in melanoma patients. Thus, the aim of this study was to investigate the effect of IL-7 regulation on
CD127 expression and CD8+ T cell responses in melanoma.
Healthy controls and primary cutaneous melanoma patients were enrolled. Membrane-bound
CD127 (mCD127) expression on CD8+ T cells was determined by flow cytometry. Soluble
CD127 (sCD127) protein level was measured by ELISA. Total
CD127 and sCD127 mRNA level was measured by real-time PCR. CD8+ T cells were stimulated with recombinant human IL-7, along with signaling pathway inhibitors. CD8+ T cells were co-cultured with melanoma cell line, and the cytotoxicity of CD8+ T cells was assessed by measurement of lactate dehydrogenase expression.
Plasma sCD127 was lower in melanoma patients compared with controls. The percentage of CD8+ T cells expressing mCD127 was higher, while sCD127 mRNA level was lower in peripheral and tumor-infiltrating CD8+ T cells from melanoma patients. There was no significant difference of total CD127 mRNA expression in CD8+ T cells between groups. IL-7 stimulation enhanced total CD127 and sCD127 mRNA expression and sCD127 release by CD8+ T cells. However, mCD127 mRNA expression on CD8+ T cells was not affected. This process was mainly mediated by phosphatidylinositol 3-kinase (PI3K) pathway. CD8+ T cells from melanoma patients exhibited decreased cytotoxicity. IL-7 stimulation promoted CD8+ T cell cytotoxicity, while inhibition of PI3K dampened IL-7-induced elevation of CD8+ T cell cytotoxicity.
The current data suggested that insufficient IL-7 secretion might contribute to CD8+ T cell exhaustion and CD127 dysregulation in patients with primary cutaneous melanoma.