精氨酸甲基转移酶PRMT1在乳腺癌细胞上皮—间质转换和细胞衰老过程中的作用及机制研究

发布时间：2018-05-03 01:14

本文选题：乳腺癌转移 + 肿瘤干细胞　；参考：《东北师范大学》2016年博士论文

【摘要】：近年来,乳腺癌在中国妇女中的发病率和致死率大大提高。乳腺癌大多数起源于乳腺上皮细胞,其致死率90%以上是源于原位瘤的转移。乳腺癌的转移需要变异的乳腺上皮细胞获得迁移及侵袭的能力,从而穿透基底膜进入周围组织,进一步进入淋巴或血液循环系统,从而扩散到远端转移位点。目前的研究认为,这一过程是通过上皮-间质转换来实现的。上皮-间质转换(Epithelial-Mesenchymal Transition,EMT)是指上皮细胞通过细胞骨架重塑,失去细胞极性和细胞间黏附能力等一系列上皮细胞表型,转而获得成纤维细胞样的间质细胞表型的过程。EMT参与癌症发生发展的多个过程,不仅促进癌细胞的侵袭和转移,还可以使癌细胞获得肿瘤干细胞特性,抵抗化疗药物的伤害,抑制细胞衰老和逃逸免疫监督等过程。某些生长因子信号通路、转录因子、microRNAs、基因的可变性剪接和一些表观调控机制都参与了EMT的调控。细胞衰老是指细胞进入一种不可逆的生长周期停滞状态。细胞衰老是机体细胞防御肿瘤发生的重要防线,丧失衰老的能力是细胞发生癌变的前提条件。诱导肿瘤细胞衰老的抗肿瘤策略已经在放化疗治疗和基因治疗方面取得了进展。近来的研究表明,细胞衰老和EMT这两个在癌症相关进程中作用截然相反的生物学事件具有十分密切的联系,这种联系主要体现在EMT与细胞衰老这两种细胞命运中存在着共同的调控因子,这些调控因子可以在诱导EMT的同时抑制细胞衰老,对肿瘤的恶性发展起到双重促进作用。因此寻找这两个生物学事件中的关键调控因子能够为肿瘤转移的治疗提供新的分子靶标。PRMT1是I类精氨酸甲基转移酶,在哺乳动物中发挥主要的精氨酸甲基转移酶功能,参与调控众多的生物学事件,如基因转录、RNA加工处理、信号转导、DNA损伤修饰和蛋白质核质转运等。PRMT1的甲基化底物蛋白数量众多,包括组蛋白H4和非组蛋白FOXO1、ERα、MRE11和53BP1等。PRMT1甲基化组蛋白H4R3发生非对称性二甲基化(H4R3me2as),此修饰在基因的转录激活过程中发挥重要的作用。已有的研究表明PRMT1在多种癌症类型中高表达,包括乳腺癌、肺癌、结肠癌、膀胱癌和血癌。然而PRMT1在乳腺癌发生发展和转移过程中的作用及调控机制尚不明确。我们的研究表明,PRMT1在高转移能力的乳腺癌细胞系中高表达。过表达PRMT1可以诱导乳腺癌细胞发生EMT,伴随着间质分子标记Fibronectin和α-SMA的表达上调和上皮分子标记E-cadherin和β-catenin的表达下调。过表达PRMT1还可以增强乳腺癌细胞的迁移和侵袭能力,干涉PRMT1不仅在细胞水平上减弱乳腺癌细胞的迁移和侵袭能力,还能抑制乳腺癌细胞在小鼠体内的肺转移。此外,PRMT1的异常表达还可以使乳腺上皮细胞获得干细胞特性和增强单细胞克隆增殖的能力。随后我们发现,干涉PRMT1使乳腺癌细胞周期进入G1四倍体生长停滞并发生衰老,伴随着p21表达的上调和G2/M期周期蛋白CDC2、CCNB1和CCNA2的表达下调。在分子机制方面,PRMT1能够通过H4R3me2as修饰转录激活ZEB1的表达,并且ZEB1的表达对PRMT1所介导的EMT及其相关功能是必需的。我们的研究探索了PRMT1通过ZEB1调控EMT与细胞衰老的表观调控机制,以期阐明乳腺癌发生发展过程中精氨酸甲基化修饰对EMT和细胞衰老的双重调控机制,为开发靶向PRMT1的乳腺癌治疗药物奠定基础。
[Abstract]:In recent years, the incidence and mortality rate of breast cancer in Chinese women are greatly increased. Most of breast cancer originates from mammary epithelial cells. The death rate of breast cancer is more than 90% from the metastasis of tumor in situ. The metastasis of breast cancer needs the ability to transfer and invasion of the mammary epithelial cells, and then penetrate the basement membrane into the surrounding tissue and enter the surrounding tissue. Step into the lymphatic or blood circulation system and spread to the distal metastasis site. Current research suggests that this process is achieved through epithelial mesenchymal transition. Epithelial mesenchymal transition (Epithelial-Mesenchymal Transition, EMT) refers to a series of epithelial cells replastic through the cytoskeleton, loss of cell polarity and intercellular adhesion. The phenotype of epithelial cells, and the process of obtaining the phenotype of fibroblast like cells,.EMT participates in many processes of cancer development. It not only promotes the invasion and metastasis of cancer cells, but also enables cancer cells to obtain the characteristics of cancer stem cells, resist the injury of chemotherapeutic drugs, inhibit cell senescence and escape immune supervision. Growth factor signaling pathway, transcription factor, microRNAs, gene mutability splicing and some apparent regulatory mechanisms are involved in the regulation of EMT. Cell senescence refers to cells entering an irreversible growth cycle stagnation. Cell senescence is a critical line of cell defense against tumor, and the loss of senescence is a cell carcinogenesis. The antineoplastic strategy for inducing tumor cell senescence has progressed in the field of chemo therapy and gene therapy. Recent studies have shown that cell senescence and EMT, the two biological events that play an opposite role in cancer related processes, are closely linked, mainly in EMT and cells. There are common regulatory factors in the fate of these two cells, which can inhibit cell senescence at the same time of inducing EMT, and play a dual role in the malignant development of the tumor. Therefore, the search for the key regulatory factors in these two biological events can provide a new molecular target for the treatment of tumor metastasis,.PRMT1 is I Arginine methyltransferase, which plays the main function of arginine methyltransferase in mammals, participates in the regulation of many biological events, such as gene transcription, RNA processing, signal transduction, DNA damage modification and protein nuclear transport, such as.PRMT1 methylation substrates, including histone H4 and non histone FOXO1, ER The asymmetric two methylation (H4R3me2as) of.PRMT1 methylation histone H4R3, such as alpha, MRE11 and 53BP1, plays an important role in the transcriptional activation of the gene. Previous studies have shown that PRMT1 is highly expressed in a variety of cancer types, including breast, lung, colon, bladder and blood cancers. However, PRMT1 is occurring in breast cancer. Our study shows that PRMT1 is highly expressed in highly metastatic breast cancer cell lines. Overexpression of PRMT1 can induce EMT in breast cancer cells, up and up with the expression of interstitial molecular markers Fibronectin and alpha -SMA, and epithelial molecular markers E-cadherin and beta -catenin The expression of PRMT1 can also enhance the migration and invasion ability of breast cancer cells. Interfering PRMT1 not only reduces the migration and invasion ability of breast cancer cells on the cell level, but also inhibits the lung metastasis of breast cancer cells in mice. In addition, the abnormal expression of PRMT1 can also make the mammary epithelial cells obtain the characteristics of stem cells and the characteristics of the breast cancer cells. Enhancing the ability of single cell clone proliferation. Then we found that interferometric PRMT1 makes the breast cancer cell cycle enter G1 tetraploid growth stagnation and senescence, accompanied by up regulation of p21 expression and G2/M period protein CDC2, CCNB1 and CCNA2 expression downregulation. In molecular mechanism, PRMT1 can activate ZEB1 expression through H4R3me2as modified transcription. And the expression of ZEB1 is necessary for the PRMT1 mediated EMT and its related functions. Our study explored the apparent regulation mechanism of PRMT1 through ZEB1 to regulate EMT and cell senescence in order to elucidate the double regulatory mechanism of arginine methylation on EMT and cell senescence during the development of breast cancer and to develop breast cancer targeting PRMT1 It lays the foundation for the treatment of drugs.

【学位授予单位】：东北师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R737.9

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