Department of Neurosurgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, China.
Department of Neurosurgery, Taihe Affiliated Hospital of Hubei University of Medicine, Shiyan, 442000, China.
Cell Death Dis. 2022 Aug 9;13(8):697. doi: 10.1038/s41419-022-05149-1.
Glioma stem cells (GSCs) are a special kind of cells in GBM showing tumor initiation, self-renewal, and multi-lineage differentiation abilities. Finding novel circRNAs related to GSCs is of great significance for the study of glioma. qPCR, western blotting, and immunohistochemistry were used to detect the expression levels of circKPNB1, SPI1, DGCR8, and TNF-α. The expression of these molecules in GSCs was regulated by lentiviral-based infection. RNA immunoprecipitation assay, RNA pull-down, dual-luciferase reporter, and chromatin immunoprecipitation assays were used to study the direct regulation mechanisms among these molecules. All the MTS, EDU, transwell, neurosphere formation assays, ELDA assays, and xenograft experiments were used to detect the malignant phenotype of GSCs. We found a novel circRNA circKPNB1 was overexpressed in GBM and associated with GBM patients' poor prognosis. CircKPNB1 overexpression can promote the cell viabilities, proliferation, invasion, neurospheres formation abilities, and stemness of GSCs. Mechanistically, circKPNB1 regulates the protein stability and nuclear translocation of SPI1. SPI1 promotes the malignant phenotype of GSCs via TNF-α mediated NF-κB signaling. SPI1 can also transcriptionally upregulate DGCR8 expression, and the latter can maintain the stability of circKPNB1 and forms a positive feedback loop among DGCR8, circKPNB1 and SPI1. Our study found circKPNB1 was a novel oncogene in GBM and of great significance in the diagnosis and prognosis prediction of GBM and maybe a novel target for molecular targeted therapy.
神经胶质瘤干细胞（GSCs）是 GBM 中一种具有肿瘤起始、自我更新和多谱系分化能力的特殊细胞。寻找与 GSCs 相关的新型 circRNAs 对胶质瘤的研究具有重要意义。qPCR、western blotting 和免疫组织化学用于检测 circKPNB1、SPI1、DGCR8 和 TNF-α 的表达水平。通过基于慢病毒的感染来调节这些分子在 GSCs 中的表达。RNA 免疫沉淀测定、RNA 下拉、双荧光素酶报告基因和染色质免疫沉淀测定用于研究这些分子之间的直接调节机制。所有 MTS、EDU、transwell、神经球形成测定、ELDA 测定和异种移植实验均用于检测 GSCs 的恶性表型。我们发现一种新型 circRNA circKPNB1 在 GBM 中过表达，并与 GBM 患者的不良预后相关。CircKPNB1 的过表达可促进 GSCs 的细胞活力、增殖、侵袭、神经球形成能力和干性。在机制上，circKPNB1 调节 SPI1 的蛋白稳定性和核转位。SPI1 通过 TNF-α 介导的 NF-κB 信号促进 GSCs 的恶性表型。SPI1 还可以转录上调 DGCR8 的表达，后者可以维持 circKPNB1 的稳定性，并在 DGCR8、circKPNB1 和 SPI1 之间形成正反馈环。我们的研究发现 circKPNB1 是 GBM 中的一种新型癌基因，对 GBM 的诊断和预后预测具有重要意义，并且可能是分子靶向治疗的新靶点。
