Department of Pathology, Division of Neuropathology, University of California San Francisco, San Francisco, CA, USA.
Department of Pathology, Oregon Health & Science University, Portland, OR, USA.
Sci Rep. 2018 Apr 11;8(1):5805. doi: 10.1038/s41598-018-24046-2.
The neurofibromin-1 tumor suppressor gene (NF1) is altered in approximately 20% of sporadic glioblastoma (GBM) cases. NF1 deficient GBM frequently shows a mesenchymal gene expression signature, suggesting a relationship between NF1 status and the tumor microenvironment. To identify changes in the production of secreted cytokines/chemokines in NF1 deficient glioma, we applied cytokine arrays to conditioned media from a panel of three GBM cell lines after siRNA-mediated NF1 knockdown. We identified increased secretion of platelet-derived growth factor AA (PDGF-AA), chitinase-3-like protein 1 (CHI3L1), interleukin-8 (IL-8), and endoglin (ENG) in different subsets of these cell lines. Secretion was associated with induction of the corresponding messenger RNA, suggesting a mechanism involving transcriptional upregulation. By contrast, in non-transformed immortalized normal human astrocytes, PDGF-AA secretion was increased upon NF1 knockdown, while secreted CHI3L1, ENG, and IL-8 were reduced or unchanged. Analysis of The Cancer Genome Atlas confirmed a relationship between glioma NF1 status and ENG and CHI3L1 in tumor samples. Overall, this study identifies candidate changes in secreted proteins from NF1 deficient glioma cells that could influence the tumor microenvironment, and suggests a direct link between NF1 loss and increased tumor cell production of CHI3L1 and endoglin, two factors implicated in mesenchymal identity in glioblastoma.
神经纤维瘤 1 型肿瘤抑制基因 (NF1) 在大约 20%的散发性胶质母细胞瘤 (GBM) 病例中发生改变。NF1 缺陷型 GBM 常表现出间充质基因表达特征，提示 NF1 状态与肿瘤微环境之间存在关系。为了鉴定 NF1 缺陷型神经胶质瘤中分泌细胞因子/趋化因子产生的变化，我们应用细胞因子阵列分析了三株 GBM 细胞系在 NF1 敲低后的条件培养基中的细胞因子/趋化因子。我们发现这些细胞系中的不同亚群中血小板衍生生长因子 AA (PDGF-AA)、几丁质酶 3 样蛋白 1 (CHI3L1)、白细胞介素 8 (IL-8) 和内格林 (ENG) 的分泌增加。分泌与相应信使 RNA 的诱导相关，提示涉及转录上调的机制。相比之下，在非转化的永生化正常人星形胶质细胞中，NF1 敲低后 PDGF-AA 的分泌增加，而分泌的 CHI3L1、ENG 和 IL-8 减少或不变。对癌症基因组图谱的分析证实了胶质母细胞瘤 NF1 状态与肿瘤样本中 ENG 和 CHI3L1 之间的关系。总的来说，这项研究确定了 NF1 缺陷型神经胶质瘤细胞中分泌蛋白的候选变化，这些变化可能影响肿瘤微环境，并提示 NF1 缺失与 CHI3L1 和内格林肿瘤细胞产生的直接联系，这两个因素都与胶质母细胞瘤中的间充质特征有关。
