POSTN 在维持胶质母细胞瘤干细胞和小胶质细胞免疫抑制表型中的双重作用。

The dual role of POSTN in maintaining glioblastoma stem cells and the immunosuppressive phenotype of microglia in glioblastoma.

机构信息

Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China.

Department of Neurosurgery, The First Affiliated Hospital of Gannan Medical University, Ganzhou, 341000, China.

出版信息

J Exp Clin Cancer Res. 2024 Sep 4;43(1):252. doi: 10.1186/s13046-024-03175-9.

DOI:10.1186/s13046-024-03175-9

PMID:39227950

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11373117/

Abstract

BACKGROUND

Glioblastoma (GBM) is an immunosuppressive, universally lethal cancer driven by glioblastoma stem cells (GSCs). The interplay between GSCs and immunosuppressive microglia plays crucial roles in promoting the malignant growth of GBM; however, the molecular mechanisms underlying this crosstalk are unclear. This study aimed to investigate the role of POSTN in maintaining GSCs and the immunosuppressive phenotype of microglia.

METHODS

The expression of POSTN in GBM was identified via immunohistochemistry, quantitative real-time PCR, and immunoblotting. Tumorsphere formation assay, Cell Counting Kit-8 assay and immunofluorescence were used to determine the key role of POSTN in GSC maintenance. ChIP-seq and ChIP-PCR were conducted to confirm the binding sequences of β-catenin in the promoter region of FOSL1. Transwell migration assays, developmental and functional analyses of CD4 T cells, CFSE staining and analysis, enzyme-linked immunosorbent assays and apoptosis detection tests were used to determine the key role of POSTN in maintaining the immunosuppressive phenotype of microglia and thereby promoting the immunosuppressive tumor microenvironment. Furthermore, the effects of POSTN on GSC maintenance and the immunosuppressive phenotype of microglia were investigated in a patient-derived xenograft model and orthotopic glioma mouse model, respectively.

RESULTS

Our findings revealed that POSTN secreted from GSCs promotes GSC self-renewal and tumor growth via activation of the αVβ3/PI3K/AKT/β-catenin/FOSL1 pathway. In addition to its intrinsic effects on GSCs, POSTN can recruit microglia and upregulate CD70 expression in microglia through the αVβ3/PI3K/AKT/NFκB pathway, which in turn promotes Treg development and functionality and supports the formation of an immunosuppressive tumor microenvironment. In both in vitro models and orthotopic mouse models of GBM, POSTN depletion disrupted GSC maintenance, decreased the recruitment of immunosuppressive microglia and suppressed GBM growth.

CONCLUSION

Our findings reveal that POSTN plays critical roles in maintaining GSCs and the immunosuppressive phenotype of microglia and provide a new therapeutic target for treating GBM.

摘要

背景

胶质母细胞瘤（GBM）是一种免疫抑制性的、普遍致命的癌症，由胶质母细胞瘤干细胞（GSCs）驱动。GSCs 与免疫抑制性小胶质细胞之间的相互作用在促进 GBM 的恶性生长中起着关键作用；然而，这种串扰的分子机制尚不清楚。本研究旨在探讨 POSTN 在维持 GSCs 和小胶质细胞免疫抑制表型中的作用。

方法

通过免疫组织化学、定量实时 PCR 和免疫印迹鉴定 GBM 中 POSTN 的表达。肿瘤球形成试验、细胞计数试剂盒-8 测定和免疫荧光用于确定 POSTN 在维持 GSC 中的关键作用。ChIP-seq 和 ChIP-PCR 用于证实β-catenin 在 FOSL1 启动子区域结合序列。Transwell 迁移试验、CD4 T 细胞的发育和功能分析、CFSE 染色和分析、酶联免疫吸附试验和凋亡检测试验用于确定 POSTN 在维持小胶质细胞免疫抑制表型从而促进免疫抑制肿瘤微环境中的关键作用。此外，分别在患者来源的异种移植模型和原位胶质瘤小鼠模型中研究了 POSTN 对 GSC 维持和小胶质细胞免疫抑制表型的影响。

结果

我们的研究结果表明，GSCs 分泌的 POSTN 通过激活αVβ3/PI3K/AKT/β-catenin/FOSL1 通路促进 GSC 自我更新和肿瘤生长。除了对 GSCs 的内在作用外，POSTN 还可以通过αVβ3/PI3K/AKT/NFκB 通路招募小胶质细胞并上调小胶质细胞中 CD70 的表达，从而促进 Treg 的发育和功能，并支持免疫抑制肿瘤微环境的形成。在体外模型和 GBM 原位小鼠模型中，POSTN 耗竭破坏了 GSC 的维持，减少了免疫抑制性小胶质细胞的募集，并抑制了 GBM 的生长。