中国科学院昆明动物研究所机构知识库

胶质母细胞瘤是恶性程度最高的肿瘤之一。目前对于脑胶质母细胞瘤的治疗主要还是手术切除为主，并辅助以放疗和替莫唑胺化疗的联合治疗方案。经过近几十年的努力，尽管在诊断和治疗上都有了明显的改善，但胶质母细胞瘤病人的生存时间仍然没有显著提高。胶质瘤内部异常高的异质性是胶质瘤难以治疗的最重要的原因之一。胶质瘤的异质性不仅出现在病人与病人之间的个体差异，在肿瘤内部同样存在不同遗传突变和表型的。探索胶质瘤的遗传突变和肿瘤发展的分子机制将为胶质瘤的研究提供理论基础。在对肿瘤的发生发展的研究中，建立合适的动物模型是研究肿瘤常规的手段。同其它肿瘤一样，脑胶质瘤也经历一系列的遗传突变、组织学特征的改变以及肿瘤的病理进程的改变。动物模型的构建对于系统的研究促使肿瘤起始、维持肿瘤生长以及肿瘤的抗治疗的信号通路和机制具有非常重要的作用。好的动物模型应该能够模拟人遗传突变的典型的分子特征，从而更好的能够为临床研究服务。在TCGA数据库分析中发现，胶质母细胞瘤中CDKN2A基因和CDKN2B基因在超过一半的胶质瘤病人中出现了基因缺失。CDKN2A和CDKN2B基因位于RB信号通路的上游主要位置上。我们在分析数据时发现CDKN2A基因和CDKN2B基因的缺失通常与TP53的缺失并不在同一个样本中出现。且从表达谱和生存曲线上看，这两种基因突变都很有可能代表了两种典型的驱动胶质瘤机制。有文献报道通过激活ras并沉默TP53可以诱导小鼠胶质母细胞瘤，因而我们尝试激活ras并失活CDKN2A基因和CDKN2B基因构建小鼠模型。我们通过CDKN2A和CDKN2B基因的失活成功的在小鼠上诱导出了胶质母细胞瘤模型。该模型具有胶质母细胞瘤典型的病理特征和分子特征。同时我们对CDKN2A/CDKN2B模型和TP53模型进行了表达谱的分析，我们发现表达谱上我们构建的肿瘤模型能很好的和人胶质瘤病人的表达谱匹配起来。这说明我们构建的肿瘤模型是具有非常具有代表性的。在肿瘤的研究中，除了构建动物模型外，寻找靶向性的分子标志物也是非常重要的研究内容。TRIM蛋白家族在除了大家所熟知的抗病毒感染等功能外，近期有越来越多的文献报道这个家族的蛋白也参与肿瘤的发生与恶性化发展。TRIM44作为TRIM家族的一个新发现的成员，在胃癌、食管癌、肺癌等很多与肿瘤相关的疾病中被发现促进肿瘤的恶性化发展。但是TRIM44目前在脑肿瘤中的功能还尚未有文献报道。为了探索TRIM44在胶质瘤中的功能，我们分析了TRIM44的表达与病人预后的关系，我们发现TRIM44表达水平与胶质瘤病人的预后成负相关的关系。同时相比正常HAC细胞，胶质瘤细胞中TRIM44的表达量要明显高。这暗示TRIM44可能在胶质瘤中可能与肿瘤的恶性程度相关。为了明确TRIM44在胶质瘤中具体发挥什么功能，我们构建了靶向于TRIM44的shRNAs。我们发现在胶质瘤细胞系和干细胞中将TRIM44敲降后可以抑制细胞的生长、增殖和克隆形成。同时TRIM44的敲降还促使细胞发生凋亡。裸鼠移植瘤实验也同样证明了TRIM44敲降后对细胞的抑制作用。而TRIM44的过表达可以促进细胞增殖和迁移。进一步的研究中我们发现将TRIM44敲降后可以抑制细胞周期并调控细胞周期相关的调控因子P21、P27以及CyclinB1。我们推测TRIM44是通过调控细胞周期来调节细胞增殖。为了继续深入探索TRIM44通过什么信号通路介导调控细胞周期，我们检测了对P21、P27以及CyclinB1有调控的信号通路，我们发现了AKT信号通路受到TRIM44的调控。而AKT信号通路可以调控P21和P27。因而我们推测TRIM44是通过AKT信号通路调控细胞周期抑制蛋白P21和P27，进而调控胶质瘤细胞的增殖，影响肿瘤的发展。

Gliomablastoma is one of the most malignant tumor. The treatment of GBM include surgical, radiation, and chemotherapy management with TMZ. Unfortunately, survival of GBM patientsis still dismal although aggressive efforts have been made. The highly heterogeneity of glioma is the main cause of complexity and difficulty to cure. The heterogeneity of glioma include not only the difference between patients of different genetic mutations, but also the difference of different cells in one tumor. To explore the genetic mutations and mechanism for glioma development is important to understand biology of glioma. Appropriate animal model construction is a conventional method to study the origin and development of tumor. Same with many cancers, gliomas undergo a series of genetic, histological and physiological changes.It is important to use animal models for systematic studying of the mechanism of tumor initiating and maintaing. The exploration of signal pathway and factors involved in the tumor growth is also the main part for animal model. The typical animal model which can represent human genetic mutations will be better understand the mechanism of glioma. We found that CDKN2A and CDKN2B deletion happened in more than half of the glioblastoma patients from TCGA database. CDKN2A and CDKN2B is the main part in RB signal pathway. We found that CDKN2A and CDKN2B deletion always happened in patients without TP53 mutation. The expression profiles and survival of patients with these different mutation are also different with each other. These results suggested that the two main mutation may initiate glioma using different pathways. Activiton of ras combine with silence of TP53 have been reported inducing glioma formation in mouse. Then we wondered whether combining ras activation with CDKN2A and CDKN2B inactivition can induce tumor formation. it is surprising that we observed tumor formation by these genes. The HE staining and immumo-histochemical staining suggest the typical pathological characteristics and molecular characteristics of glioblastoma of these tumors. According to the patients expression profiles difference between the CDKN2A/CDKN2B deletion and TP53 mutation, we analyzed the expression profiles of our corresponding mouse model. The expression profiles of mouse tumors map corrected with corresponding patients. The results suggested that the ras-CDKN2A-CDKN2B is highly representative. Excepting the model constrution, it is also an important part to find out more targeting molecular markers in glioma research. The new function of TRIM family in carcinogenesis have been reported in kinds of tumors except their antiviral infection function. As one of them, TRIM44 have been found can promote tumor progression in gastric cancer, esophageal cancer, lung cancer and so on. But the function in glioma of TRIM44 is still unknown. Here we found higer expression level of TRIM44 is related with worse survival of glioma patients from TCGA database. At the same ime, we found that the epression of TRIM44 in glioma cell is also higher than normal human cerebellar astrocyte cell line HAC. These results indicate possible function of TRIM44 in glioma.To explore the function of TRIM44 in glioma, we construct two shRNAs to knockdown TRIM44 in glioma cells. We found TRIM44 knockdown inhibite glioma cell growth and clone formation and migration in vitro. In vivo experiment by using dox induced TRIM44 knockdown found TRIM44 also inhibited tumor growth.The tumor volume of TRIM44 knockdown group is much smaller than control group. Knockdown of TRIM44 induce apoptosis in glioma cells. While overexpression of TRIM44 promote cell growth and migration. These results suggest TRIM44 plays an important role for glioma development. To further confirm the mechanism of TRIM44 regulating cell growth, we found that cell cycle inhibitor p21, p27 have been upregulated and cyclinB1 is downregulated thus leading to cell cycle arrest. After a series of signal pathway seletion, we found AKT pathway which have reported to regulate P21and p27 have been found regulated by TRIM44 in glioma. All these results indicate TRIM44 promote glioma cell growth by regulating cell cycle through AKT pathway.