NKAP alters tumor immune microenvironment and promotes glioma growth via Notch1 signaling
NKAP alters tumor immune microenvironment and promotes glioma growth via Notch1 signaling
复制标题
NKAP 通过 Notch1 信号改变肿瘤免疫微环境并促进神经胶质瘤生长
DOI：
10.1186/s13046-019-1281-1
复制
发表时间：
2019-07-06
影响因子：
11.3
通讯作者：
Liu, Qian
中科院分区：
文献类型：
--
作者：
Gu, Guangyan;Gao, Taihong;Liu, Qian
背景胶质瘤是一种侵袭性最强的恶性脑肿瘤，具有高度浸润性生长和预后差的特点。NKAP（NF-kappa B activating protein，NF-κ B活化蛋白）是一种由415个氨基酸组成的核蛋白，在胶质瘤中广泛表达，但其在胶质瘤中的作用尚不清楚。免疫荧光法检测NKAP、Notch 1和SDF-1的表达。采用免疫组化方法检测NKAP和Notch 1在胶质瘤和正常人脑组织中的表达。此外，还采用CHIP、基因芯片、western blot、流式细胞术、免疫荧光、ELISA和荧光素酶等方法研究了NKAP与Notch 1之间的内在联系。结果NKAP在胶质瘤中的过表达可通过促进Notch 1依赖的免疫抑制肿瘤微环境而促进肿瘤生长。神经胶质瘤中NKAP的下调在体外和体内都废除了肿瘤的生长和侵袭。有趣的是，与对照组相比，抑制NKAP通过减少SDF-1和M-CSF的分泌来阻碍肿瘤相关巨噬细胞（TAM）的极化和募集。为了确定所涉及的潜在机制，我们进行了RNA测序分析，发现Notch 1似乎与NKAP的表达呈正相关。NKAP通过与Notch 1启动子结合并反式激活Notch 1发挥其功能，抑制Notch 1可减轻NKAP对胶质瘤的促生长作用。结论NKAP通过上调Notch 1的表达，通过TAM的化学吸引作用促进胶质瘤的生长。
BackgroundGlioma is one of the most aggressive malignant brain tumors which is characterized with highly infiltrative growth and poor prognosis. NKAP (NF-kappa B activating protein) is a widely expressed 415-amino acid nuclear protein that is overexpressed by gliomas, but its function in glioma was still unknown.MethodsCCK8 and EDU assay was used to examine the cell viability in vitro, and the xenograft models in nude mice were established to explore the roles of NAKP in vivo. The expressions of NKAP, Notch1 and SDF-1 were analyzed by immunofluorescence analysis. The expression of NKAP and Notch1 in glioma and normal human brain samples were analyzed by immunohistochemical analysis. In addition, CHIP, Gene chip, western blot, flow cytometry, immunofluorescence, ELISA and luciferase assay were used to investigate the internal connection between NKAP and Notch1.ResultsHere we showed that overexpression of NKAP in gliomas could promote tumor growth by contributing to a Notch1-dependent immune-suppressive tumor microenvironment. Downregulation of NKAP in gliomas had abrogated tumor growth and invasion in vitro and in vivo. Interestingly, compared to the control group, inhibiting NKAP set up obstacles to tumor-associated macrophage (TAM) polarization and recruitment by decreasing the secretion of SDF-1 and M-CSF. To identify the potential mechanisms involved, we performed RNA sequencing analysis and found that Notch1 appeared to positively correlate with the expression of NKAP. Furthermore, we proved that NKAP performed its function via directly binding to Notch1 promoter and trans-activating it. Notch1 inhibition could alleviate NKAP's gliomagenesis effects.Conclusionthese observations suggest that NKAP promotes glioma growth by TAM chemoattraction through upregulation of Notch1 and this finding introduces the potential utility of NKAP inhibitors for glioma therapy.