Greehey Children's Cancer Research Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas,USA.
Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
Neuro Oncol. 2023 Mar 14;25(3):459-470. doi: 10.1093/neuonc/noac179.
The loss of neurogenic tumor suppressor microRNAs miR-124, miR-128, and miR-137 is associated with glioblastoma's undifferentiated state. Most of their impact comes via the repression of a network of oncogenic transcription factors. We conducted a high-throughput functional siRNA screen in glioblastoma cells and identify E74 like ETS transcription factor 4 (ELF4) as the leading contributor to oncogenic phenotypes.
In vitro and in vivo assays were used to assess ELF4 impact on cancer phenotypes. We characterized ELF4's mechanism of action via genomic and lipidomic analyses. A MAPK reporter assay verified ELF4's impact on MAPK signaling, and qRT-PCR and western blotting were used to corroborate ELF4 regulatory role on most relevant target genes.
ELF4 knockdown resulted in significant proliferation delay and apoptosis in GBM cells and long-term growth delay and morphological changes in glioma stem cells (GSCs). Transcriptomic analyses revealed that ELF4 controls two interlinked pathways: 1) Receptor tyrosine kinase signaling and 2) Lipid dynamics. ELF4 modulation directly affected receptor tyrosine kinase (RTK) signaling, as mitogen-activated protein kinase (MAPK) activity was dependent upon ELF4 levels. Furthermore, shotgun lipidomics revealed that ELF4 depletion disrupted several phospholipid classes, highlighting ELF4's importance in lipid homeostasis.
We found that ELF4 is critical for the GBM cell identity by controlling genes of two dependent pathways: RTK signaling (SRC, PTK2B, and TNK2) and lipid dynamics (LRP1, APOE, ABCA7, PLA2G6, and PITPNM2). Our data suggest that targeting these two pathways simultaneously may be therapeutically beneficial to GBM patients.
神经源性肿瘤抑制 microRNAs miR-124、miR-128 和 miR-137 的缺失与神经胶质瘤的未分化状态有关。它们的大部分作用是通过抑制致癌转录因子网络来实现的。我们在神经胶质瘤细胞中进行了高通量功能 siRNA 筛选，发现 E74 样 ETS 转录因子 4（ELF4）是导致致癌表型的主要因素。
采用体外和体内测定法来评估 ELF4 对癌症表型的影响。我们通过基因组和脂质组学分析来描述 ELF4 的作用机制。MAPK 报告基因测定验证了 ELF4 对 MAPK 信号的影响，qRT-PCR 和 Western blot 用于证实 ELF4 对大多数相关靶基因的调节作用。
ELF4 敲低导致 GBM 细胞增殖明显延迟和凋亡，以及神经胶质瘤干细胞（GSCs）长期生长延迟和形态改变。转录组分析显示，ELF4 控制着两条相互关联的通路：1）受体酪氨酸激酶信号通路；2）脂质动力学。ELF4 调节直接影响受体酪氨酸激酶（RTK）信号通路，因为丝裂原激活蛋白激酶（MAPK）活性依赖于 ELF4 水平。此外，shotgun 脂质组学显示 ELF4 耗竭破坏了几种磷脂类，突出了 ELF4 在脂质动态平衡中的重要性。
我们发现 ELF4 通过控制两条依赖通路的基因来控制 GBM 细胞的身份：RTK 信号通路（SRC、PTK2B 和 TNK2）和脂质动力学（LRP1、APOE、ABCA7、PLA2G6 和 PITPNM2）。我们的数据表明，同时靶向这两条通路可能对 GBM 患者具有治疗益处。
