11C-MET-PET/CT引导下多点转录组学分析脑干胶质瘤的细胞功能异质性

11C-MET-PET/CT guided multi-target biopsy and transcriptome analysis demonstrated the cellular functional heterogeneity in DIPG

目的探讨在11C-MET正电子发射断层显像(11C-MET-PET)/CT引导下转录组学分析弥散内生型脑桥胶质瘤(DIPG)组织不同区域的细胞功能异质性。方法前瞻性纳入2017年1—12月首都医科大学附属北京天坛医院神经外科收治的6例DIPG患者,术前均行头颅MRI、11C-MET-PET/CT检查。将11C-MET-PET/CT图像导入GEAW4.5工作站软件,测量肿瘤的MET标准化最大摄取值(SUVmax),据此将肿瘤区域分为MET高、中、低摄取区,术中对MET高、低摄取区进行活组织检查取材。通过对组织样本进行基因组测序,比较6例患者MET高、低摄取区的差异表达基因,观察热点突变情况,同时进行基因本体(GO)和信号通路富集分析。结果6例患者的肿瘤组织MET高摄取区较低摄取区表达上调的基因数为296~1768个,表达下调的为558~1476个。6例患者的肿瘤组织MET高、低摄取区常见热点突变的检测结果为,1例BCOR突变,4例H3F3A突变,1例PIK3CA突变,5例TP53突变,1例PPM1D突变(仅11C-MET低摄取区检测到)。GO和信号通路富集分析结果显示,与肿瘤组织的MET低摄取区比较,高摄取区表达上调的基因主要富集在肿瘤增殖、侵袭及新生血管生成,而表达下调的基因主要参与免疫细胞趋化、免疫反应及对干扰素反应等生物学过程。结论DIPG组织内部呈现细胞功能的异质性,MET高摄取区较低摄取区高表达肿瘤恶性生物学行为相关基因,低表达免疫抑制及肿瘤耐药相关基因;且11C-MET-PET/CT对于区分肿瘤细胞生物学功能具有诊断价值。

Objective To explore the cellular heterogeneity between 11C-methionine (11C-MET) high and low regions in the diffuse intrinsic pontine glioma (DIPG) using 11C-MET-PET/CT guided multiple-target biopsy and transcriptome analysis. MethodsSix DIPG patients admitted to Department of Neurosurgery,Beijing Tiantan Hospital,Capital Medical University from January 2017 to December 2017 were included in this prospective study. The 11C-MET-PET/CT image was imported into GE AW4.5 workstation software to measure the maximum methionine uptake value (SUVmax) of the tumor,and the tumor area was divided into methionine high uptake zone,middle uptake zone and low uptake zone. Biopsy was performed on the high and low intake areas of methionine. By sequencing the tissue samples,the differentially expressed genes and hotspot mutations in the high and low methionine regions of 6 patients were compared,and gene ontology (GO) analysis and signal pathway enrichment analysis were performed. ResultsThe number of genes up-regulated in the methionine-high uptake area of tumor tissues in 6 patients was 296-1 768,and the expression was down-regulated from 558 to 1 476. The results of detection of common hotspot mutations in methionine high and low uptake areas of 6 patients were as follows: 1 BCOR mutation,4 H3F3A mutations,1 PIK3CA mutation,5 TP53 mutations,and 1 PPM1D mutation (detected only in the 11C-MET low uptake region). GO and signal pathway enrichent analysis showed that compared with the low methionine uptake area of tumor tissue,the genes highly expressed in the high uptake area were mainly involved in tumor proliferation,invasion and neovascularization,while the low expressed genes were mainly involved in immune cell chemotaxis,immune response and biological processes such as the reaction to interferon. ConclusionsThe heterogeneity of cell function is exhibited in the tissues of DIPG. Compared with the lower uptake region of methionine,high uptake region has high expression of tumor malignant biological behavior-related genes and low expression of immunosuppressive and tumor resistance-related genes. 11C-MET-PET/CT could have diagnostic value in distinguishing the biological functions of tumor cells.