Her2/ Elk1信号轴通过调控LUC7L3表达促进脑膜瘤增殖和侵袭的分子机制研究

Meningiomas is very common in primary central nervous system. we still have 7-20% possibility to recur after benign meningiomas was complete resected. A lot of studies have shown Her2 gene expressed abnormal in meningiomas which can promote cell proliferation and invasion of meningiomas. However, the underlying mechanism is unclear. By using gene chip and high throughput screening assay, We found the expression of Cisplatin resistance-associated over-expressed (LUC7L3) increased obviously when Her2 gene was over-expressed, and when we silenced LUC7L3, the cells grow slowly At the same time, when we tried to analyze LUC7L3 gene promoter, we hypothesis the phosphorylation of transcription factor Elk1 is probable the key protein in Her2 signal pathway that has effect on LUC7L3 regulating cell of proliferation. Based on these previous studies, we try to regulate LUC7L3 expression to detect the relationship between LUC7L3 and Her2, as well as their effects on proliferation and invasion by MTT and Transwell assays, etc.. Furthermore, we will explore whether Her2/Elk1 signal pathway affects the expression of LUC7L3 through Elk1 and promotes proliferation and invasion of meningioma cells. As far as we know the mechanism, we could provide theoretical basis for individualized thearpy of the meningiomas.

脑膜瘤是中枢神经系统常见的原发性肿瘤，即使良性脑膜瘤患者术后也可有7-20%复发的可能性。研究发现大量脑膜瘤组织中存在Her2基因表达水平增高的情况，而Her2促进肿瘤的增殖和侵袭，但分子机制尚不明。我们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，顺铂耐药性过表达相关蛋白（LUC7L3）显著增加；下调LUC7L3表达，脑膜瘤细胞的增殖能力明显下降。同时通过对LUC7L3启动子预测分析发现：在Her2 信号通路中，Elk1的磷酸化可以调节LUC7L3的表达，进而影响细胞的增殖。本课题拟通过调控LUC7L3的表达，检测LUC7L3、Elk1、Her2的调控关系，采用MTT、Transwell小室、裸鼠成瘤等实验检测LUC7L3增殖、侵袭功能，阐明Her2/Elk1信号轴通过调控LUC7L3表达促进脑膜瘤增殖和侵袭的分子机制，为探索脑膜瘤个体化治疗提供理论依据。

脑膜瘤是最常见的原发性颅内肿瘤。组织学恶性程度增高(WHOⅡ级或III级)的高达20%。除放射治疗外，缺乏有效的药物治疗。因此，有必要对恶性脑膜瘤的发病机制进行研究，为其提供更多的治疗策略。目的：探讨HER2/ ELK1信号轴通过调控LUC7L3表达促进脑膜瘤增殖的分子机制。方法：我们通过基因芯片筛选技术比较HER2激活前后脑膜瘤细胞中的差异基因，筛选出了LUC7L3基因；同时对LUC7L3启动子分析，发现 LUC7L3 启动子上具有 ELK1 的结合位点。RT-qPCR和Western blot检测HER2抑制剂处理后的恶性脑膜瘤IOMM-Lee细胞内LUC7L3、ELK1、P- ELK1、HER2的表达。采用CHIP和双荧光素酶报告基因实验证实转录因子ELK1和基因启动子LUC7L3的结合情况。此外，用sh-LUC7L3和ox-LUC7L3干扰恶性脑膜瘤IOMM-Lee细胞，并与其阴性对照比较，使用RT-qPCR检测各组细胞LUC7L3mRNA表达水平，并在裸鼠体内注射转染sh-LUC7L3和ox-LUC7L3慢病毒的IOMM-Lee细胞，观察肿瘤的生长情况。结果：干扰 HER2 基因后，恶性脑膜瘤IOMM-Lee细胞珠中 LUC7L3、 ELK1、P- ELK1、HER2的表达水平降低。LUC7L3启动子区存在与转录因子 ELK1结合位点。通过裸鼠成瘤实验验证实验结果，沉默LUC7L3可抑制体内肿瘤的生长，过表达LUC7L3可促进内肿瘤的生长。结论：脑膜瘤中 LUC7L3 为 HER2/ ELK1信号轴的下游靶基因，HER2信号通路激活后，通过影响转录因子 ELK1的磷酸化，上调LUC7L3基因，促进脑膜瘤细胞的增殖。