【作者】 张超；

【导师】 王艳东；

【作者基本信息】 北京化工大学 ， 药学， 2020， 硕士

【摘要】 脑垂体瘤属于常见的中枢神经系统类肿瘤之一,其发病率约占脑部肿瘤总发病率的10%。而在脑垂体瘤中泌乳素瘤和生长激素瘤是主要的发病类型。并且研究发现脑垂体瘤的发病率正呈现低龄化的趋势。脑垂体瘤对病人的危害极大,能够引起代谢紊乱和内分泌失调等,临床表现为肢端肥大和多器官功能衰竭等。因此对脑垂体瘤进行深入研究十分重要。法尼酯X受体(FXR)属于核受体家族,在身体的多种器官中均有分布,其主要参与胆汁酸和脂质的稳态调节。近几年的研究报道发现FXR还可以在炎症和癌症中发挥重要的作用。AMP依赖的蛋白激酶(AMPK)是一种异三聚体酶,由α亚基、β亚基和γ亚基组成,其中起主要催化作用的是α亚基。AMPK的主要功能是参与调节生物的能量代谢,同时有报道提及AMPK激酶在癌症的调节中也发挥重要作用。在本课题中我们研究发现FXR受体通过调控AMPK信号通路实现对脑垂体瘤的抑制作用。在本课题中,我们主要通过体外实验和体内实验两大部分对FXR受体在脑垂体瘤中的作用机制进行研究。在体外实验中,我们采用大鼠脑垂体瘤GH3细胞进行实验,并用FXR人工合成的配体激动剂GW4064激活FXR受体。在MTT实验中发现激活FXR受体抑制GH3细胞的增殖;在细胞划痕实验中发现激活FXR受体对GH3细胞的迁移没有明显影响;在细胞周期和凋亡实验中发现激活FXR受体后将细胞周期阻滞在G0/G1期并诱发细胞凋亡;在Real-time PCR实验中检测到激活FXR受体后可以使促凋亡的BAX、Caspase-9以及AMPK上游靶基因LKB1的基因表达量上升,可以使抑凋亡的Bcl-2以及与细胞周期相关的CDK2、Cyclin E1、Cyclin D1的基因表达量下降;在Western Blot实验中检测到FXR受体激活可促进AMPK蛋白磷酸化。在体内实验中,我们运用BALB/c裸鼠构建了裸鼠成瘤模型,经过腹腔注射GW4064激活FXR受体之后抑制裸鼠体内的GH3细胞诱导的肿瘤的生长;在Real-time PCR实验中,肿瘤组织中用GW4064激活FXR受体可使促凋亡的BAX以及AMPK上游靶基因LKB1的基因表达量上升,可以使抑凋亡的Bcl-2以及与周期相关的CDK2、Cyclin E1的基因表达量下降。综上所述,激活的FXR受体通过诱导AMPK信号通路抑制脑垂体瘤细胞的生长从而抑制脑垂体瘤的发展。所以,FXR受体是一种潜在的脑垂体瘤治疗药物设计靶点。更多还原

【Abstract】 Pituitary adenoma is one of the most common central nervous system tumors.Pituitary adenomas account for about 10%of brain tumors and the incidence is increasing in recent years.PRL-secreting pituitary adenomas and GH-secreting pituitary adenomas are the main kinds of the pituitary adenoma.Pituitary tumors are harmful to patients,which can cause metabolic and endocrine disorders.In addition,the clinical symptoms of pituitary adenomas are acromegaly and multisystem organ failure.Further pathogenesis researches of pituitary adenomas are urgent for many patients.FXR,as a ligand activated transcription factor,is a nuclear receptor(NR).And FXR can be detected in many organs.Many reports showed that FXR was involved in metabolic regulations such as bile acid,lipid and glucose metabolism.FXR also plays an important role in the regulation of inflammation and cancer.Adenosine 5’-monophosphate(AMP)-activated protein kinase(AMPK)is a heterotrimeric enzyme,which comprise of catalytic α subunit,β subunit,and y subunit.The main function of AMPK is to regulate the energy metabolism of organisms.In addition,reports in recent years mentioned that AMPK played a key role in regulating the development of cancer.In our study,we showed that FXR inhibited the progression of pituitary adenomas through AMPK signal pathway.In this project,the mechanism of FXR in pituitary adenomas was studied through in vitro and in vivo experiments.In vitro experiments,FXR activation by GW4064 inhibited GH3 cell proliferation and had no significant effect on cell migration.Activated FXR induced cell apoptosis and cell cycle arrest in G0/G1 phase.We also found that FXR activation suppressed the expression of CDK2,Cyclin E1,Cyclin D1 and Bcl-2.Furthermore,FXR activation promoted the expression of LKB1,BAX and Caspase-9.In western blot analysis,FXR activation induced the expression of phosphorylated AMPK.In xenograft model studies,FXR activation repressed the growth of xenograft tumor.Moreover,FXR activation suppressed the expression of CDK2,Cyclin E1 and Bcl-2 and promoted the expression of LKB1 and BAX in xenograft.In summary,FXR activation can effectively repress the progression of pituitary adenomas by inducing AMPK signal pathway.Therefore,FXR is a potential target for pituitary adenomas treatment.更多还原