Deng Xin, Song Laijun, Zhao Wen, Wei Ying, Guo Xin-Bin
Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Key Laboratory of Advanced Pharmaceutical Technology, Ministry of Education of China, Zhengzhou, China.
Front Cell Neurosci. 2017 Dec 21;11:420. doi: 10.3389/fncel.2017.00420. eCollection 2017.
Glioblastoma is the most common malignant tumor in central nervous system (CNS), and it is still insurmountable and has a poor prognosis. The proliferation and survival mechanism of glioma cells needs to be explored further for the development of glioma treatment. Hematopoietic-substrate-1 associated protein X-1 (HAX-1) has been reported as an anti-apoptosis protein that plays an important role in several malignant tumors. However, the effect and mechanism of HAX-1 in glioblastomas remains unknown. This study aimed to investigate the effect of HAX-1 in glioblastoma cells and explore the mechanism. The results of clone formation and Edu proliferation assay showed slower multiplication in HAX-1 knock-out cells. Flow cytometry showed cell cycle arrest mainly in G0/G1 phase. Apoptosis due to oxidative stress was increased after HAX-1 was knocked out. Western-blot assay exhibited that the levels of p21, Bax, and p53 proteins were significantly raised, and that the activation of the caspase cascade was enhanced in the absence of HAX-1. The degradation rate and ubiquitination of p53 declined because of the decrease in phosphorylation of proteins MDM2 and Akt1. Co-immunoprecipitation (Co-IP) and immunefluorescent co-localization assays were performed to test the influence of HAX-1 on the interaction between Akt1 and Hsp90, which is crucial for the activity of Akt1. In conclusion, this novel study suggested that HAX-1 could affect the Akt1 pathway through Hsp90. The knock-out of HAX-1 leads to the inactivity of the Ak1t/MDM2 axis, which leads to increased levels of p53, and finally generates cell cycle arrest and results in the apoptosis of glioblastoma cells.
胶质母细胞瘤是中枢神经系统（CNS）中最常见的恶性肿瘤，目前仍然难以攻克，预后较差。为了开发胶质瘤治疗方法，胶质瘤细胞的增殖和存活机制需要进一步探索。造血底物-1相关蛋白X-1（HAX-1）已被报道为一种抗凋亡蛋白，在几种恶性肿瘤中发挥重要作用。然而，HAX-1在胶质母细胞瘤中的作用和机制仍不清楚。本研究旨在探讨HAX-1对胶质母细胞瘤细胞的影响并探索其机制。克隆形成和Edu增殖试验结果显示，HAX-1基因敲除细胞的增殖较慢。流式细胞术显示细胞周期主要停滞在G0/G1期。HAX-1基因敲除后，氧化应激诱导的细胞凋亡增加。蛋白质免疫印迹分析表明，p21、Bax和p53蛋白水平显著升高，在缺乏HAX-1的情况下，半胱天冬酶级联反应的激活增强。由于MDM2和Akt1蛋白磷酸化减少，p53的降解率和泛素化水平下降。进行了免疫共沉淀（Co-IP）和免疫荧光共定位分析，以检测HAX-1对Akt1与Hsp90相互作用的影响，这对Akt1的活性至关重要。总之，这项新研究表明，HAX-1可能通过Hsp90影响Akt1信号通路。HAX-1基因敲除导致Akt1/MDM2轴失活，从而导致p53水平升高，最终导致细胞周期停滞并导致胶质母细胞瘤细胞凋亡。
