在许多类型的人类癌症中观察到PD-L1的过表达,包括胶质母细胞瘤(GBM),并有助于肿瘤免疫逃避。此外,由于磷酸果糖激酶1血小板亚型(PFKP)的过表达,GBM显示高度激活的有氧糖酵解,糖酵解的关键酶。然而,目前尚不清楚代谢酶PFKP是否在调节PD-L1表达和GBM免疫逃避中发挥作用。
我们旨在研究PFKP在PD-L1表达诱导的GBM免疫逃避中的非代谢性作用。
通过几个实验研究了PFKP诱导PD-L1表达的机制,包括实时PCR,免疫印迹分析,和ATP生产。使用GBM细胞和T细胞进行共培养实验以评估PFKP对T细胞活化的影响。在癌症基因组图谱(TCGA)数据库和人GBM标本中分析了PFKP和PD-L1之间的临床关系。
我们表明PFKP促进人GBM细胞中EGFR活化诱导的PD-L1表达。重要的是,我们证明EGFR磷酸化的PFKPY64在AKT介导的β-catenin反式激活和随后的PD-L1转录表达中起重要作用,从而增强GBM免疫逃避。此外,根据我们的发现,人GBM标本中PFKPY64磷酸化水平与PD-L1表达呈正相关,强调PFKPY64磷酸化在GBM免疫逃避中的临床意义。
这些发现为通过PFKP对肿瘤细胞的非代谢功能调节PD-L1表达提供了新的机制见解。
Overexpression of PD-L1 is observed in many types of human cancer, including glioblastoma (GBM) and contributes to tumor immune evasion. In addition, GBM shows highly-activated aerobic glycolysis due to overexpression of phosphofructokinase 1 platelet isoform (PFKP), which the key enzyme in the glycolysis. However, it remains unclear whether the metabolic enzyme PFKP plays a role in the regulation of PD-L1 expression and GBM immune evasion.
We aimed to investigate the non-metabolic role of PFKP in PD-L1 expression-induced GBM immune evasion.
The mechanisms of PFKP-induced PD-L1 expression were studied by several experiments, including real-time PCR, immunoblot analysis, and ATP production. The coculture experiments using GBM cell and T cells were performed to evaluate the effect of PFKP on T cell activation. The clinical relationship between PFKP and PD-L1 was analyzed in The Cancer Genome Atlas (TCGA) database and in human GBM specimens.
We showed that PFKP promotes EGFR activation-induced PD-L1 expression in human GBM cells. Importantly, we demonstrated that EGFR-phosphorylated PFKP Y64 plays an important role in AKT-mediated β-catenin transactivation and subsequent PD-L1 transcriptional expression, thereby enhancing the GBM immune evasion. In addition, based on our findings, the levels of PFKP Y64 phosphorylation are positively correlated with PD-L1 expression in human GBM specimens, highlighting the clinical significance of PFKP Y64 phosphorylation in the GBM immune evasion.
These findings provide new mechanistic insight into the regulation of PD-L1 expression by a non-metabolic function of PFKP on tumor cells.