Endothelins influences the proliferation-migration balance of IDH1-mutant glioma cells and promotes proneural to mesenchymal transition [RNAseq-Gb7-HUVEC]

Adult diffuse gliomas are the deadliest brain tumours including IDH-wildtype glioblastomas of worst prognosis and diffuse low grade IDH-mutant astrocytomas and oligodendrogliomas. These glial tumours display distinct tumoral cell population defeating current therapies. Our group has unveiled the role of NOTCH signalling in glioblastoma cell plasticity and in the conversion of oligodendrocytic-like to astrocytic-like tumoral cells in IDH-mutant low-grade gliomas which escalate inevitably to higher grade malignant gliomas. To gain insight into signalling pathways regulating glioma cell plasticity and malignancy, we focused our work on endothelin signalling including endothelin peptide ligands (ET-1, ET-2, ET-3) binding to G-protein coupled endothelin receptors A and B (EDNRA, EDNRB). Here, using glioma patient samples and glioma patient-derived cell lines, we showed that endothelin reduces glioma cell proliferation while increasing migration initiating a proneural to mesenchymal transition. Mechanistically, EDNRB activation led to IP3-dependent calcium mobilization, apamin-sensitive KCNN2/KCNN3 potassium currents and phosphorylation of ERK1/2 and STAT3 in glioma cells. Finally, we studied endothelin receptor regulation by tumoral microenvironment stimuli highlighting a role for EDNRA induced by NOTCH and hypoxia in perivascular hypoxic area in glioblastoma. Altogether, this study demonstrates endothelin signalling as a key player in mesenchymal transformation of diffuse IDH-mutant gliomas and glioblastomas. RNAseq analyses of Gb7 glioblastoma stem cell line cells upon coculture with HUVEC endothelial cells (Human Umbilical Vein Endothelial Cells)

成人弥漫性胶质瘤是致死性最高的脑肿瘤，涵盖预后最差的IDH野生型（IDH-wildtype）胶质母细胞瘤，以及弥漫性低级别IDH突变型星形细胞瘤和少突胶质细胞瘤。这类神经胶质肿瘤存在独特的肿瘤细胞群，可逃逸现有治疗手段。本团队已揭示NOTCH信号通路（NOTCH signalling）在胶质母细胞瘤细胞可塑性中的作用，以及在不可避免进展为高级别恶性胶质瘤的IDH突变型低级别胶质瘤中，介导类少突胶质细胞瘤细胞向类星形细胞瘤细胞转化的功能。为深入探究调控胶质瘤细胞可塑性与恶性表型的信号通路，本研究聚焦于内皮素信号通路（endothelin signalling）：该通路包含可结合G蛋白偶联内皮素受体A（EDNRA）与B（EDNRB）的内皮素肽配体（ET-1、ET-2、ET-3）。本研究通过胶质瘤患者样本及患者来源的胶质瘤细胞系开展实验，证实内皮素可抑制胶质瘤细胞增殖，同时促进细胞迁移并诱发原神经亚型向间充质亚型的表型转化。机制层面上，在胶质瘤细胞中，EDNRB激活可触发依赖三磷酸肌醇（IP3）的钙动员、对apamin敏感的KCNN2/KCNN3钾电流，以及细胞外调节蛋白激酶1/2（ERK1/2）与信号转导与转录激活因子3（STAT3）的磷酸化。最后，本研究探究了肿瘤微环境刺激对内皮素受体的调控作用，明确了NOTCH与缺氧在胶质母细胞瘤血管周缺氧区域诱导EDNRA表达的关键作用。综上，本研究证实内皮素信号通路是弥漫性IDH突变型胶质瘤及胶质母细胞瘤发生间充质转化的核心调控通路。针对与HUVEC内皮细胞（人脐静脉内皮细胞，Human Umbilical Vein Endothelial Cells）共培养的Gb7胶质母细胞瘤干细胞系细胞所开展的RNA测序（RNA-seq）分析