组蛋白去甲基化酶JMJD2A通过靶向Akt-mTOR信号通路促进胶质瘤细胞生长。
The histone demethylase JMJD2A promotes glioma cell growth via targeting Akt-mTOR signaling.
作者信息
Li Min, Cheng Jingmin, Ma Yuan, Guo Heng, Shu Haifeng, Huang Haidong, Kuang Yongqin, Yang Tao
机构信息
Department of Neurosurgery, General Hospital of Western Theater Command, Chengdu, No. 270, Rongdu Avenue, Jinniu District, Chengdu, China.
出版信息
Cancer Cell Int. 2020 Mar 30;20:101. doi: 10.1186/s12935-020-01177-z. eCollection 2020.
BACKGROUND
A number of JmjC domain-containing histone demethylases have been identified and biochemically characterized in mammalian models and humans. JMJD2A is a transcriptional co-factor and enzyme that catalyzes the demethylation of histone H3 lysine 9 and 36 (H3K9 and H3K36). Here in this study, we reported the role of JMJD2A in human glioma.
METHODS
Quantitative real-time PCR and western blot were performed to analyzed JMJD2A expression in glioma. Log-rank was performed to plot the survival curve. JMJD2A was knocked or overexpressed with lentivirus. Cell proliferation and colony formation were performed to assess the effects of JMJD2A on glioma cell growth. Xenograft experiment was performed the evaluate the growth rate of glioma cells in vivo. The signaling pathway was analyzed with western blot and mTOR was inhibited with rapamycin.
RESULTS
Quantitative real-time PCR and western blot experiments revealed higher expression of JMJD2A and lower levels of H3K9me3/H3K36me3 in glioma tissues than that in normal brain tissues. We showed that knockdown of expression attenuated the growth and colony formation in three lines of glioma cells (U251, T98G, and U87MG), whereas overexpression resulted in opposing effects. Furthermore, we performed in vivo xenograft experiments and our data demonstrated that knockdown reduced the growth of glioma T98G cells in vivo. Further mechanism study implicated that activated the Akt-mTOR pathway and promoted protein synthesis in glioma cells via promoting phosphoinositide-dependent kinase-1 ( expression. The activation of the Akt-mTOR pathway was also validated in human glioma tissues. Finally, we showed that inhibition of mTOR with rapamycin blocked the effects of on protein synthesis, cell proliferation and colony formation of glioma cells.
CONCLUSIONS
These findings demonstrated that JMJD2A regulated glioma growth and implicated that JMJD2A might be a promising target for intervention.
背景
在哺乳动物模型和人类中，已鉴定出多种含JmjC结构域的组蛋白去甲基化酶，并对其进行了生化特性分析。JMJD2A是一种转录辅因子和酶，可催化组蛋白H3赖氨酸9和36（H3K9和H3K36）的去甲基化。在本研究中，我们报道了JMJD2A在人类胶质瘤中的作用。
方法
采用定量实时PCR和蛋白质印迹法分析胶质瘤中JMJD2A的表达。采用对数秩检验绘制生存曲线。用慢病毒敲低或过表达JMJD2A。进行细胞增殖和集落形成实验以评估JMJD2A对胶质瘤细胞生长的影响。进行异种移植实验以评估胶质瘤细胞在体内的生长速率。用蛋白质印迹法分析信号通路，并用雷帕霉素抑制mTOR。
结果
定量实时PCR和蛋白质印迹实验显示，胶质瘤组织中JMJD2A的表达高于正常脑组织，而H3K9me3/H3K36me3的水平低于正常脑组织。我们发现，敲低JMJD2A的表达可减弱三种胶质瘤细胞系（U251、T98G和U87MG）的生长和集落形成，而过表达则产生相反的效果。此外，我们进行了体内异种移植实验，数据表明敲低JMJD2A可降低胶质瘤T98G细胞在体内的生长。进一步的机制研究表明，JMJD2A通过促进磷酸肌醇依赖性激酶-1（PDK1）的表达激活Akt-mTOR通路并促进胶质瘤细胞中的蛋白质合成。Akt-mTOR通路的激活在人类胶质瘤组织中也得到了验证。最后，我们发现用雷帕霉素抑制mTOR可阻断JMJD2A对胶质瘤细胞蛋白质合成、细胞增殖和集落形成的影响。
结论
这些发现表明JMJD2A调节胶质瘤生长，并提示JMJD2A可能是一个有前景的干预靶点。
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