Department of Human and Molecular Genetics, Institute of Molecular Medicine, VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia 23298, USA.
Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
Neuro Oncol. 2023 May 4;25(5):841-853. doi: 10.1093/neuonc/noac238.
ALKBH5 is aberrantly activated and exerts critical roles in facilitating the development of glioblastoma. However, the underlying activation mechanism by which ALKBH5 protein is increased in glioblastoma is not completely understood. Our study aimed to elucidate the signaling pathways involved in mediating ALKBH5 protein stability.
The contribution of deubiquitinating enzymes (DUB) to the fluctuation of ALKBH5 protein expression was globally profiled with western blot analysis. Mass spectrometry and immunoprecipitation were performed to identify the USP36 and ALKBH5 interaction. The effects of USP36 on the stability of ALKBH5 were detected with in vivo and in vitro ubiquitination assays. Cell proliferation assays, neurosphere formation, limited dilution assay, and intracranial tumor growth assays were implemented to assess the collaborative capacities of USP36 and ALKBH5 in tumorigenesis.
Ubiquitin-specific peptidase 36 (USP36), as a potential ALKBH5-activating DUB, played an essential role in stabilization of ALKBH5 and regulation of ALKBH5-mediated gene expression in glioblastoma. The depletion of USP36 drastically impaired cell proliferation deteriorated the self-renewal of GSCs and sensitized GSCs to temozolomide (TMZ) treatment. Furthermore, the deletion of USP36 substantially decreased the in vivo tumor growth when monitored by bioluminescence imaging. Our findings indicate that USP36 regulates the protein degradation and expression of ALKBH5, and the USP36-ALKBH5 axis orchestrates glioma tumorigenesis.
Our findings identify USP36 as a DUB of ALKBH5 and its role in glioblastoma progression, which may serve as a potential therapeutic target for glioblastoma treatment.
ALKBH5 异常激活，并在促进胶质母细胞瘤的发展中发挥关键作用。然而，ALKBH5 蛋白在胶质母细胞瘤中增加的潜在激活机制尚不完全清楚。我们的研究旨在阐明介导 ALKBH5 蛋白稳定性的信号通路。
通过 Western blot 分析全面分析了去泛素化酶 (DUB) 对 ALKBH5 蛋白表达波动的贡献。进行质谱分析和免疫沉淀以鉴定 USP36 和 ALKBH5 相互作用。通过体内和体外泛素化测定检测 USP36 对 ALKBH5 稳定性的影响。实施细胞增殖测定、神经球形成、有限稀释测定和颅内肿瘤生长测定，以评估 USP36 和 ALKBH5 在肿瘤发生中的协同作用。
泛素特异性肽酶 36（USP36）作为潜在的 ALKBH5 激活 DUB，在稳定 ALKBH5 和调节 ALKBH5 在胶质母细胞瘤中的基因表达方面发挥了重要作用。USP36 的耗竭严重损害了细胞增殖，恶化了 GSCs 的自我更新，并使 GSCs 对替莫唑胺（TMZ）治疗敏感。此外，通过生物发光成像监测时，USP36 的缺失大大降低了体内肿瘤的生长。我们的研究结果表明，USP36 调节 ALKBH5 的蛋白降解和表达，USP36-ALKBH5 轴协调胶质瘤的发生。
我们的研究结果确定 USP36 是 ALKBH5 的 DUB 及其在胶质母细胞瘤进展中的作用，这可能成为胶质母细胞瘤治疗的潜在治疗靶点。
