FTL调控GADD45信号通路及其在脑胶质母细胞瘤细胞增殖中的作用及机制研究

There are accumulating evidences that iron metabolism related proteins play pivotal roles for tumor initiation and development，but its mechanism in glioblastoma multiforme(GBM) has not been comprehensively studied. We found that Ferritin light chain (FTL), a key protein of iron metabolism was closely associated with GBM patient’s survival by using bioinformatics method. Our pilot study showed that FTL expression was elevated in GBM, and its down-regulation in GBM cells resulted in growth inhibition and activation of GADD45 signaling pathway, more importantly, FTL interacted physically with GADD45A, overexpression of FTL inhibited the expression of GADD45A while proteasome inhibitors attenuated the effects. Accordingly, we hypothesize that FTL-regulated GADD45 pathway is crucial to the proliferation of GBM cells, and FTL is involved in the proteasome-dependent degradation of GADD45A. By using multiple methods including RNA interference, proximity ligation assay, co-immunoprecipitation, ubiquitination assay, we will explore the function and mechanism of the FTL-regulated GADD45 pathway on GBM cells proliferation. The study aims to elucidate the novel mechanism of GBM molecular pathology and offer a new perspective for GBM targeting therapy.

铁代谢相关蛋白在肿瘤发生发展中起重要作用，但其在人脑胶质母细胞瘤（GBM）中的研究报道甚少。铁蛋白轻链（FTL）是该类蛋白重要成员，本项目组利用生物信息挖掘技术发现FTL在GBM的表达与患者预后密切相关。预实验结果提示：FTL在GBM中高表达；下调FTL在GBM细胞的表达可抑制其增殖并激活GADD45信号通路；FTL可直接结合GADD45A； FTL高表达可抑制GADD45A表达，蛋白酶体抑制剂则减弱该抑制作用。据此推测：FTL调控 GADD45信号通路影响GBM细胞增殖，分子机制为FTL结合GADD45A并促进后者经泛素-蛋白酶体途径降解。为验证假设，本项目将采用载体转染、RNA干扰、邻位连接技术、免疫共沉淀、泛素化检测等技术，从分子-细胞-组织及动物水平探讨该调控机制。本研究拟揭示FTL与GADD45A相互作用影响GBM细胞增殖的关键机制，为GBM分子靶向治疗提供新思路。

研究发现铁代谢相关蛋白在肿瘤发生发展中发挥重要作用，而在人脑胶质母细胞瘤（GBM）的研究较少。铁蛋白轻链（FTL）是该类蛋白重要成员，生物信息数据挖掘提示FTL与GBM关系密切。本项目采用载体转染、RNA干扰、邻位连接技术、免疫共沉淀、泛素化检测等技术，从分子-细胞-组织及动物水平，探讨FTL调控GBM细胞增殖及GADD45A/JNK信号通路的作用及机制。结果发现，FTL在人脑胶质母细胞瘤中高表达且与胶质瘤级别、患者预后相关；FTL在GBM细胞中主要表达于细胞核，且与细胞有丝分裂过程密切相关；下调FTL在GBM细胞的表达可显著抑制其增殖并激活GADD45信号通路；免疫学技术显示FTL可直接结合GADD45A； FTL高表达可抑制GADD45A表达，蛋白酶体抑制剂则减弱该抑制作用；动物实验显示敲低FTL可以在体内水平抑制GBM细胞生长。本研究提示FTL是一个促癌基因，其可以通过调节GADD45A/JNK信号通路调控GBM细胞的增殖，分子机制是通过结合GADD45A介导GADD45A通过泛素-蛋白酶体降解。本研究提供了FTL有可能作为一个新的GBM治疗靶点，并为以后的临床应用提供实验依据