关键基因在前庭神经鞘膜瘤囊性变中的发现及其作用机制研究

The cystic vestibular schwannoma(CVS) was reported in 1/3 of all dignosed cases. The severe symptoms, formidable management and poor surgical outcomes provide it for an important clinical significance. The biological pathogenesis of CVS in not yet clarified, even though there were several hypothesis. Our previous studies indicated firstly in the world that the mutations of NF2 gene, the major morbigenous gene in pathogenesis of vestibular schwannoma, are not involved in cystic formation precedure. We confirmed five candidate key genes, specially downregulated between CVS and solid vestibular schwannoma, via cDNA microarray analysis and qRT-PCR. Furthermore, discovery of key genes and study of thier effect mechanism would help to reveal the pathogenesis of cystic formation of vestibular schwannoma. Therefore, this study will include two successive parts, in vitro and in vivo experiments. Firstly, in vitro experiment, depending on the effects on cell growth and apoptosis in diffent cell lines,including primary cystic or solid vestibular schwannoma cells, human schwan cell(HSC) and vestibular schwannoma cell line(HEI-193), we confirm the key genes of cystic formation of vestibular schwannoma from candidate key genes silencing and overexpressing systems.Secondly, in vivo experiment, we research the possible effect mechanism of key genes on cystic formation of vestibular schwannoma via the key gene silencing system and immitation of pathogenesis of CVS in cerebellopontine angle and internal acoustic meatus region in NF2 transgenic tumor mice model.

前庭神经鞘膜瘤囊性变约占其总诊断率的1/3，症状严重，治疗棘手，疗效不佳，对该病的研究具有重要临床意义。囊性变分子生物学机制未明，诸多假说依据亦不充分。通过前期工作，我们在国际上首先提出前庭神经鞘膜瘤主要致病基因NF2并未直接涉及其囊性变机制，通过cDNA芯片和qRT-PCR，我们检测和验证了5个在囊性前庭神经鞘膜瘤中特异性下调表达的关键候选基因，寻找其中的关键基因并研究其作用机制，将有助于揭示该病囊性变形成机制。本研究拟以离体和在体两部分递进实验，于离体实验部分通过沉默和过表达系统关键候选基因，根据对不同细胞系（囊性、实性前庭神经鞘膜瘤原代细胞、HSC和HEI-193细胞系）生长和凋亡的影响，确认前庭神经鞘膜瘤囊性变关键基因，再于在体实验部分在NF2转基因肿瘤小鼠中沉默桥小脑角和内听道区域的关键基因表达，模拟囊性变过程，获得关键基因对于前庭神经鞘膜瘤囊性变的可能作用机制。

前庭神经鞘膜瘤（VS）为内听道及桥小脑角最多见良性肿瘤，囊性变后肿瘤体积增大 、症状加重、侵袭性更甚，手术指证强烈，但手术疗效不佳。因此，探究VS囊性变机制具有临床重要意义。囊性变分子生物学机制未明，诸多假说依据亦不充分。通过cDNA芯片和qRT-PCR，我们检测和验证了在囊性前庭神经鞘膜瘤中特异性下调表达的关键基因，沉默和过表达关键基因，观察前庭神经鞘膜瘤囊性变关键基因对不同细胞系（囊性、实性前庭神经鞘膜瘤原代细胞、HSC和HEI-193细胞系）生长和凋亡的影响。本项目重点关注前庭神经鞘膜瘤囊性变的可能作用机制，首次通过miRNA高通量测序从转录组层面解析导致实性与囊性前庭神经鞘膜瘤转录谱差异变化的关键调控分子，发现miRNA205通过调控靶基因PTEN影响CVS细胞增殖能力，在前庭神经鞘膜瘤中具有关键作用。以上研究为前庭神经鞘膜瘤囊性变机制的基础研究奠定重要基础，为寻找VS囊性变的关键诊疗靶点及CVS靶向治疗提供有力依据。