TMEM106B通过Her2信号通路影响脑膜瘤增殖和血管生成的研究

Meningiomas are the second most common type of tumour in the central nervous system. Studies showed Her2 play roles in progressive of many type of tumors. Our previous research has shown Her2 gene expressed in meningiomas and associated with the tumor grade and recurrence; down-regulation of Her2 expression inhibits cell proliferation and angiogenesis. However, which protein or gene participates in these phenomenon, what is the underlying mechanism, these remain unclear. TMEM106B is associated with non-neoplastic diseases such as Alzheimer’s Disease in the central nervous system, but what the effect of TMEM106B on tumors such as meningiom is unknown to now. We found expression of TMEM106B is significantly increased in meningiomas as well as over-expression of Her2 by gene chip. And after down-regulating TMEM106B expression, proliferation ability of meningiomas cells was decreased. By analysis of TMEM106B gene promoter, we found transcription factor JUN may interact with it, and up-regulation of JUN might be an important factor between Her2 and TMEM106B. Based on our previous studies, this project plans to explore the association relationship between TMEM106B and Her2 ,as well as effects of cell proliferation and angiogenesis of meningioma regulated by TMEM106B through collecting clinical specimen, detecting cell functions and etc.. Therefore, we will offer new methods for clinical research of the meningiomas.

脑膜瘤发病率居颅内肿瘤第二位。目前研究发现Her2参与多种肿瘤发生发展。我们前期研究发现脑膜瘤组织中存在Her2表达且与肿瘤分级、复发相关，下调Her2可抑制脑膜瘤增殖和血管生成，但Her2信号通路中何种因子对此起调控作用及其潜在机制是什么，目前尚不清。TMEM106B与中枢神经系统非肿瘤性疾病如阿尔茨海默病密切相关，但其在肿瘤如脑膜瘤的发生发展中作用如何，目前尚未检索到相关报道。通过基因芯片和高通量筛选发现，过表达Her2的脑膜瘤细胞TMEM106B含量显著增加，下调TMEM106B引起增殖能力明显减弱。通过对TMEM106B启动子分析发现上调的JUN可能是Her2与TMEM106B的重要枢纽。本课题拟通过细胞功能检测、裸鼠成瘤等实验方法探讨TMEM106B、JUN、Her2之间相关性以及TMEM106B对脑膜瘤增殖和血管生成的影响，进而为脑膜瘤的研究提供新思路。

脑膜瘤是颅内第二常见的肿瘤，约占颅内原发肿瘤的30%。脑膜瘤复发率较高，良性脑膜瘤患者术后复发率有7-20%，恶性脑膜瘤生长速度快，具有高侵袭性，复发率高达50-94%，患者的预后差。课题组前期实验发现脑膜瘤组织中存在Her2基因表达水平增高的情况，而Her2促进肿瘤的增殖和侵袭。通过基因芯片和高通量筛选发现：脑膜瘤中Her2信号通路激活时，TMEM106B显著增加；下调TMEM106B表达，脑膜瘤细胞的增殖能力明显下降。同时通过对TMEM106B启动子预测分析发现：在Her2信号通路中，JUN的磷酸化可以调节TMEM106B的表达，进而影响细胞的增殖。使用免疫组织化学法、Western blot、q-PCR法检测脑膜瘤和脑膜组织中TMEM106B和Her2表达情况，结果显示TMEM106B和Her2在脑膜瘤组织表达水平高于脑膜组织，且两者表达水平呈正相关。MTT、EdU增殖实验结果显示，沉默脑膜瘤细胞株TMEM106B，细胞增殖能力降低。小管形成实验结果显示，沉默脑膜瘤细胞株TMEM106B，细胞血管生成能力降低。裸鼠成瘤实验，沉默TMEM106B，裸鼠成瘤的能力减弱。Her2抑制剂Afatinib（BIBW2992）干扰恶性脑膜瘤株后，q-PCR和Western blot检测Her2、JUN和VEGF的mRNA和蛋白表达水平呈正相关。双重荧光素酶测定和染色质免疫沉淀（CHIP）实验，结果提示Her2可能通过调控转录因子JUN的表达而对TMEM106B表达产生影响。以上结果表明，TMEM106B通过Her2信号通过影响脑膜瘤增殖和血管生成。这个机制的提出为临床治疗提出了新思路，为恶性脑膜瘤的分子靶向治疗提供了理论基础。