肿瘤转移相关蛋白MTA1在小鼠附睾中的表达及功能研究

发布时间：2018-07-21 19:27

【摘要】： 侵袭和转移是导致各种恶性肿瘤患者死亡的主要原因,并受多种基因的调控。近年来,已相继克隆出许多与肿瘤转移直接相关的“肿瘤转移相关基因”,其中有Yasushi Toh等从鼠和人类乳腺癌转移细胞系中筛选克隆出肿瘤候选基因MTA1 (metastasis associated gene 1,肿瘤转移相关基因1)。肿瘤转移相关基因(MTA)是一个基因家族,现已确认3类(MTA1, MTA2, MTA3)及6个亚型(MTA1, MTA1s, MTA1-ZG29p, MTA2, MTA3, MTA3L),其中MTA1, MTA2, MTA3均被认为是细胞核小体重构和脱乙酰基(NuRD)复合物的组成部分,它们通过影响染色质的状态来调整DNA复制,调控组蛋白乙酰化状态从而发挥生物学功能。研究表明,MTA1与人类许多恶性肿瘤的侵袭转移过程紧密相关,在乳腺癌、卵巢癌、胃肠肿瘤、前列腺癌和食管癌等肿瘤细胞中都呈过表达。MTA1在NuRD复合物中与组蛋白去乙酰化酶1 (HDAC1)结合紧密,与组蛋白去乙酰化成正相关,作为组蛋白去乙酰化酶的辅助激动因子抑制转录,成为转录过程中一个辅助抑制因子。Mazumdar等报道,雌激素受体(ER)阳性的乳腺细胞中hereglutin /HER2信号传导通路的激活可刺激MTA1的表达,MTA1结合于ER的AF2 (ER的一个配体结合位点),同时MTA1与HDAC2结合,使HDAC2募集于含ER反应元件的启动子附近,进而组蛋白去乙酰化增加,使雌激素受体作用元件激活的基因转录受阻,使乳腺癌发展成更具侵袭特性的恶性表型。MTA1作为组蛋白修饰物,在不同肿瘤的侵袭和转移过程中都发挥了不同程度的促进作用。目前,国内外对MTA1的研究大部分着眼于其在肿瘤转移过程的作用机理,而其生理功能的研究甚少。研究表明,MTA1不仅在肿瘤细胞中过表达,在哺乳动物正常细胞组织中也有表达,尤其是睾丸与胸腺组织,提示MTA1可能在这两种组织发育过程中起到了更为重要的作用。为了更好的理解这一组蛋白修饰物的生理作用,我们前期观察了MTA1在人、鼠睾丸发育过程中的表达,揭示了它在精子发生减数分裂阶段起了基因修饰的关键作用。众所周之,精子在附睾内移行并逐渐成熟的过程是其获得运动能力和受精能力的保证,而这一过程同样受到雄激素的调控。鉴于MTA1在精子发生过程中的重要作用,我们研究它在附睾中不同部位不同细胞类型的表达定位,分析它在精子成熟、运输和储存过程的作用,并深入探讨了雄激素对MTA1的调控作用机制,进一步明确它在生殖系统中表达的生理意义。本实验分为四部分: 第一部分:MTA1在正常成年小鼠组织中的表达第二部分:MTA1在正常小鼠附睾中的表达与定位第三部分:MTA1在小鼠生后不同发育阶段附睾中的表达第四部分:建立去势模型分析雄激素对MTA1的调控作用本实验观察了MTA1在正常成年小鼠各组织中的表达谱,结果显示MTA1广泛表达于小鼠各类组织器官,提示MTA1在多系统多器官的生理功能调节中发挥了重要的基因修饰作用。同时,我们揭示这一新的分子在附睾上皮细胞中的区段特异性表达特点。MTA1主要定位于附睾上皮细胞胞核,可能通过组蛋白乙酰化修饰作用对附睾上皮细胞重吸收、分泌及内吞过程起到一定调控作用,间接维持精子成熟的内环境稳定。小鼠生后附睾发育过程中,MTA1的表达随雄激素分泌水平呈趋势性变化,并参与附睾成熟过程。建立去势模型并给予DHT,观察小鼠附睾中MTA1的表达差异,提示雄激素对MTA1表达可能有正性调控作用,为后续研究其信号传导机制提供依据。
[Abstract]:Invasion and metastasis are the main causes of death in various malignant tumors and are regulated by a variety of genes. In recent years, many "tumor metastasis related genes" which have been cloned directly related to tumor metastasis have been cloned, including Yasushi Toh and so on from mouse and human mammary cancer metastatic cell lines to clone and clone the tumor candidate gene MTA1 (me Tastasis associated gene 1, tumor metastasis related gene 1). The tumor metastasis related gene (MTA) is a gene family, which has been identified as 3 categories (MTA1, MTA2, MTA3) and 6 subtypes (MTA1, MTA1s, MTA1-ZG29p, MTA2, MTA3), which are considered to be the components of the cell nuclear reconfiguration and the deacetylation complex. They regulate DNA replication by regulating the state of chromatin, regulate histone acetylation, and exert biological functions.
The study shows that MTA1 is closely related to the invasion and metastasis of many human malignant tumors. In breast cancer, ovarian cancer, gastrointestinal tumor, prostate cancer and esophageal cancer,.MTA1 is closely associated with histone deacetylase 1 (HDAC1) in the NuRD complex, and is positively related to histone deacetylation, as histone The adjuvant agonist of acetylase inhibits transcription and becomes a supplementary inhibitory factor.Mazumdar in the transcription process. The activation of the hereglutin /HER2 signaling pathway in the estrogen receptor (ER) positive breast cells stimulates the expression of MTA1, and MTA1 is combined with AF2 of ER (a ligand binding site of ER), while MTA1 and HDAC2 are combined, HDAC2 is raised near the promoter of the ER reaction element, and then the histone deacetylation is increased and the gene transcription activated by the estrogen receptor action element is blocked, and the breast cancer is developed into a more invasive, malignant phenotype,.MTA1, as a histone modifier, and to varying degrees in the invasion and metastasis of different tumors. Promoting effect.
At present, most studies on MTA1 are focused on the mechanism of its role in the process of tumor metastasis, and the study of its physiological functions is very small. The study shows that MTA1 is not only overexpressed in tumor cells, but also expressed in normal mammalian cells, especially in the testis and thymus gland, suggesting that MTA1 may have developed in these two tissues. In order to better understand the physiological role of this histone modifier, we have observed the expression of MTA1 during the development of human and rat testicles, and revealed that it plays a key role in gene modification during the meiosis stage of spermatogenesis.
The process of sperm migration and maturation in the epididymis is the guarantee of its ability to gain exercise and fertilization, and this process is also regulated by androgens. In view of the important role of MTA1 in the process of spermatogenesis, we study its location in different parts of the epididymis and the analysis of it in spermatozoa. The role of maturation, transportation and storage process and the mechanism of androgens' regulation on MTA1 are discussed and the physiological significance of its expression in the reproductive system is further clarified. This experiment is divided into four parts:
Part one: expression of MTA1 in normal adult mice
The second part: the expression and localization of MTA1 in normal mouse epididymis.
The third part: the expression of MTA1 in epididymis at different developmental stages in mice.
The fourth part: establishment of castration model to analyze androgen regulating effect on MTA1.
In this experiment, the expression of MTA1 in the tissues of normal adult mice was observed. The results showed that MTA1 was widely expressed in various tissues and organs of mice, suggesting that MTA1 played an important gene modification in the physiological function regulation of multiple systems and multiple organs. .MTA1 is mainly located in the nucleus of epididymal epithelial cells, which may play a regulatory role in the reabsorption of epididymal epithelial cells through the histone acetylation modification, and indirectly maintain the internal stability of the sperm maturation. The expression of MTA1 in the development process of the epididymis of mice is trend to the level of androgen secretion. Change, and participate in the epididymal maturation process. Establish a castration model and give DHT to observe the difference in the expression of MTA1 in the epididymis of mice, suggesting that androgen has a positive regulatory effect on the expression of MTA1, which provides a basis for the follow-up study of the signal transduction mechanism.
【学位授予单位】：第四军医大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R346

【相似文献】