GalNAc-T14/IGFBP-3作用对人胶质瘤细胞中ERK和NF-κB通路的影响及调控促凋亡机制的研究

Glioma seriously threats to human health. The progression of glioma's pathogenetic condition is regulated by many intracellular signaling pathways, among which the ERK and NF-κB signaling pathways are two important ones that can regulate tumor cell proliferation and apoptosis. IGFBP-3 is one of the key signaling molecules that influence the generation and development of glioma. In the meantime IGFBP -3 engages in regulation of the ERK and NF-κB signaling pathways. We found that GalNAc-T14 can be combined with IGFBP-3, involved in regulating its biological function particularly its role to affect tumor cell apoptosis. Clinical sample analysis showed that patients have relatively severe disease progression when their IGFBP-3 expression was increased and GalNAc-T14 expression was reduced. Relevant, these patients are also found with increased activation of ERK signaling pathway and NF-κB expression in abnormal elevation. This study will analyze expression of GalNAc-T14 and IGFBP-3 in clinical specimens as well as expression and phosphorylation change of signaling molecules in ERK and NF-κB pathways, then combine with characteristics of expression and activation of signaling molecules in ERK and NF-κB pathways observed through overexpression and knockdown of these genes in glioma cell lines, clarify molecular regulation mechanism and the effect that interaction of GalNAc-T14/ IGFBP-3 has on ERK and NF-κB signaling pathways, eventually provide new ideas and new targets for treatment of glioma.

胶质瘤严重威胁人类健康，其病情进展受到众多胞内信号通路调控，其中ERK和NF-κB通路是调控肿瘤增殖和凋亡的重要途径。IGFBP-3是影响胶质瘤发生和发展的关键细胞因子之一，且同时参与了上述通路的调节。我们研究发现GalNAc-T14能结合IGFBP-3，调节其生物功能，特别是对细胞凋亡的作用。临床样本检测表明：IGFBP-3表达升高，GalNAc-T14表达降低的患者病情较严重，并伴随ERK活化水平升高和NF-κB异常表达。本研究拟分析临床标本中GalNAc-T14、IGFBP-3及ERK和NF-κB通路中信号分子的表达和磷酸化，结合细胞系中过表达和敲低上述基因发现的ERK和NF-κB通路中信号分子的表达和活化水平的特征，阐明GalNAc-T14/IGFBP-3作用对ERK和NF-κB通路的影响及分子调控机制，为胶质瘤的治疗提供新思路和新靶点。

.本研究通过分析临床34例胶质瘤样本,发现GalNAc-T14和IGFBP-3在正常脑组织及星形细胞瘤组织标本中的表达有显著差异性,提示其可能与星形细胞瘤的发生发展及恶性程度有密切关系；检测结果表明，肿瘤患者组织标本中ERK1/2的磷酸化水平明显增强,其下游调控基因Bcl-XL的表达显著升高.同时利用多形性胶质母细胞瘤U87MG细胞株研究了GalNAc-T14、IGFBP-3及其相互作用对细胞增殖和凋亡的影响,探讨了二者调控ERK信号通路的可能生物学机制.研究发现GalNAc-T14在胞内高表达可以抑制ERK1/2及Bcl-XL的表达,促进U87MG细胞的凋亡;而IGFBP-3在胞内高表达可以明显增强ERK1/2的磷酸化水平及增加Bcl-XL的表达,体外加入IGFBP-3对肿瘤细胞有明显的促增殖作用,同样增强ERK1/2的磷酸化及Bcl-XL的表达,；共转染GalNAc-T14和IGFBP-3后,U87MG细胞凋亡明显增加,结果分析提示可能与GalNAc-T14的拷贝数远高于IGFBP-3的拷贝数有关,表明GalNAc-T14可以拮抗IGFBP-3的功能,验证了GalNAc-T14的促凋亡作用.总之, GalNAc-T14 和IGFBP-3在人脑星形细胞瘤中的表达差异与肿瘤的病情进展密切相关,并可能通过调控ERK信号通路和Bcl-XL的表达影响肿瘤细胞的增殖或凋亡,提示这可能是二者影响星形胶质母细胞瘤病情进展的方式之一.