Department of Neurosurgery, Tangshan People's Hospital, Tangshan, Hebei, 063001, China.
The Cancer Institute, Tangshan People's Hospital, Tangshan, Hebei, 063001, China.
Ann Clin Transl Neurol. 2023 Jun;10(6):865-878. doi: 10.1002/acn3.51743. Epub 2023 May 7.
Glioblastoma (GBM) is the most aggressive brain tumor. Reportedly, circular RNAs (circRNAs) participate in regulation of the development and progression of diverse cancers, including GBM.
Dysregulated circRNAs in GBM tissues were screened out from GEO database. The expression of candidate circRNAs in GBM cells was measured by qRT-PCR. Loss-of function assays, including colony formation assay, EdU assay, TUNEL assay, and flow cytometry analysis were conducted to determine the effects of circ-AHCY knockdown on GBM cell proliferation and apoptosis. Animal study was further used to prove the inhibitory effect of circ-AHCY silencing on GMB cell growth. Mechanistic experiments like luciferase reporter, RNA pull-down and RNA-binding protein immunoprecipitation (RIP) assays were performed to unveil the downstream molecular mechanism of circ-AHCY. Nanosight Nanoparticle Tracking Analysis (NTA) and PKH67 staining were applied to identify the existence of exosomes.
Circ-AHCY was confirmed to be highly expressed in GBM cells. Circ-AHCY silencing suppressed GBM cell proliferation both in vitro and in vivo. Mechanistically, circ-AHCY activates Wnt/β-catenin signaling pathway by sequestering miR-1294 to up-regulate MYC which activated CTNNB1 transcription. It was also found that circ-AHCY recruited EIF4A3 to stabilize TCF4 mRNA. Enhanced levels of TCF4 and β-catenin contributed to the stability of TCF4/β-catenin complex. In turn, TCF4/β-catenin complex strengthened the transcriptional activity of circ-AHCY. Exosomal circ-AHCY derived from GBM cells induced abnormal proliferation of normal human astrocytes (NHAs).
Exosomal circ-AHCY forms a positive feedback loop with Wnt/β-catenin signaling pathway to promote GBM cell growth.
胶质母细胞瘤（GBM）是最具侵袭性的脑肿瘤。据报道，环状 RNA（circRNA）参与多种癌症的发展和进展，包括 GBM。
从 GEO 数据库中筛选出 GBM 组织中失调的 circRNA。通过 qRT-PCR 测量候选 circRNA 在 GBM 细胞中的表达。进行了包括集落形成试验、EdU 试验、TUNEL 试验和流式细胞术分析在内的功能丧失试验，以确定 circ-AHCY 敲低对 GBM 细胞增殖和凋亡的影响。进一步进行动物研究以证明 circ-AHCY 沉默对 GMB 细胞生长的抑制作用。进行了诸如荧光素酶报告、RNA 下拉和 RNA 结合蛋白免疫沉淀（RIP）测定等机制实验，以揭示 circ-AHCY 的下游分子机制。纳米粒子跟踪分析（NTA）和 PKH67 染色用于鉴定外泌体的存在。
证实 circ-AHCY 在 GBM 细胞中高度表达。circ-AHCY 沉默抑制了 GBM 细胞的体外和体内增殖。机制上，circ-AHCY 通过隔离 miR-1294 来激活 Wnt/β-catenin 信号通路，从而上调激活 CTNNB1 转录的 MYC。还发现 circ-AHCY 招募 EIF4A3 以稳定 TCF4 mRNA。增强的 TCF4 和 β-catenin 水平有助于 TCF4/β-catenin 复合物的稳定性。反过来，TCF4/β-catenin 复合物增强了 circ-AHCY 的转录活性。源自 GBM 细胞的外泌体 circ-AHCY 诱导正常人类星形胶质细胞（NHAs）异常增殖。
外泌体 circ-AHCY 与 Wnt/β-catenin 信号通路形成正反馈环，促进 GBM 细胞生长。
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