miR-21靶基因列表

miR-21在乳腺癌中的生物学效应及临床意义+张惠娟谭敦勇A(吉首大学医学研究中心，吉首416000)摘要乳腺癌是女性最常见的恶性肿瘤之一。

近年来越来越多的研究发现microRNA的异常表达 与乳腺癌的发生、转移及预后关系密切，其中miR-21在多种非实体瘤和实体瘤均高表达，其在乳腺 癌中的表达及作用已成为研究热点。

本文就miR-21在乳腺癌发生发展中的生物学效应及临床意 义等相关研究做一综述。

关键词MIR-21;乳腺癌；生物学效应中图分类号R737;Q522乳腺癌是女性最常见的恶性肿瘤之一，具有发 病率高，侵袭性强等特点。

近年来，随着人们对乳腺 癌生物异质性的不断认识以及基因组学和蛋白质组 学等研究的不断深入，乳腺癌已逐渐被当作多个单 独的分子病理实体来对待，并使得人们可通过识别 乳腺癌潜在的治疗诊断IE点来提高肿瘤治疗的针对 性。

在这些潜在的治疗诊断靶点中，小分子RNA (microRNA)作为一类重要的调控因子，可通过复杂 的基因调控网络在人体内许多正常的生理进程中发 挥保守且关键的作用，同时亦可参与肿瘤细胞的增 殖、凋亡、转移、侵袭及放化疗抵抗等，在肿瘤的发 生、发展中扮演着重要的角色m。

其中，irnR-21在 人体组织和细胞中较早发现，且广泛存在，与乳腺癌 的发生、发展和转移关系密切，本文就miR-21在乳 腺癌发生发展中的生物学效应及临床意义等相关研 究做一综述。

一、miR-21的生物学特征microRNA是一类新近发现的多功能小分子，它 可以在转录后水平靶向调控mRNA，参与基因的转 录后调控，miR-21是单个基因编码的microRNA,位 于第17号染色体17q23. 2上的一段非编码序列，在 常见的脆性位点FRA17B内，含有22个核苷酸，对 肿瘤细胞的增殖、凋亡、侵袭和转移等生物学特征产 生重大影响，是第一个在肿瘤患者血清中检测到的 microRNA，是目前发现的唯一在慢性淋巴细胞性白 血病、B细胞性淋巴瘤等非实体瘤以及乳腺癌、胃癌、肝癌、肺癌、结肠癌、前列腺癌、胰腺癌、头颈部肿 瘤、食管癌等实体肿瘤中表达均高于相应正常组织的 microRNA[2]。

miR-21、miR-31、miR-92a及Let-miR-21:miR-21 is a small non-coding RNA molecule that belongs to the miRNA family. It is expressed in various tissues and plays an essential role in regulating gene expression. miR-21 has been implicated in the development and progression of various diseases, including cancer, cardiovascular disease, fibrosis, and inflammation.In cancer, miR-21 is frequently overexpressed and is associated with increased tumorigenesis, invasion, and metastasis. It has been shown to regulate several targets involved in different signaling pathways, such as PTEN, PDCD4, and RECK, which are involved in regulating cell proliferation, apoptosis, and invasion. Moreover, miR-21 has been identified as a potential biomarker for several types of cancer, including breast, lung, colon, and pancreatic cancer.In cardiovascular disease, miR-21 has been shown to play a role in regulating cell survival and apoptosis in cardiac cells. It has also been implicated in the development of cardiac hypertrophy, fibrosis, and ischemic injury. In addition, miR-21 has been found to contribute to the development of atherosclerosis by regulating the expression of pro-inflammatory cytokines and metalloproteinases.In fibrosis, miR-21 has been shown to play a role in regulating the activity of fibroblasts and myofibroblasts, which are involved in the deposition of extracellular matrix (ECM) and tissue remodeling. It has been implicated in the development of liver fibrosis, pulmonary fibrosis, and renal fibrosis.miR-31:miR-31 is another member of the miRNA family that plays a crucial role in regulating gene expression. It has been implicated in various biological processes, including cell differentiation, proliferation, migration, and apoptosis. miR-31 has been identified as a potential biomarker for several types of cancer, including breast, lung, colon, and bladder cancer.In cancer, miR-31 has been shown to inhibit the expression of several targets involved in cell proliferation, migration, and invasion, such as SATB2, ITGA5, and RDX. It has been shown to have both tumor-suppressive and oncogenic properties, depending on the cellular context and the presence of other co-factors.In addition to cancer, miR-31 has been implicated in the development and progression of several other diseases, including cardiovascular disease, inflammation, and fibrosis. In cardiovascular disease, miR-31 has been shown to regulate cardiac remodeling and hypertrophy, as well as cellular apoptosis and survival. In inflammation, miR-31 has been shown to regulate the expression of pro-inflammatory cytokines, such as IL-6 and IL-8, which are involved in the development of several inflammatory diseases.miR-92a:miR-92a is another member of the miRNA family that regulates gene expression. It has been shown to play a crucial role in regulating angiogenesis, cell proliferation, and apoptosis. miR-92a has been identified as a potential oncogene and is frequently overexpressed in various types of cancer, including ovarian, breast, and gastric cancer.In cancer, miR-92a has been shown to inhibit the expression of several targets involved in tumor suppression, including PTEN and PDCD4. It has been shown to promote the proliferation and migration of cancer cells and plays a crucial role in tumor angiogenesis by regulating the expression of several pro-angiogenic factors, including VEGF and FGF2.In addition to cancer, miR-92a has been implicated in the development and progression of several other diseases, including cardiovascular disease, fibrosis, and inflammation. In cardiovascular disease, miR-92a has been shown to regulate endothelial cell function and angiogenesis, as well as cellular apoptosis and survival. In fibrosis, miR-92a has been shown to regulate tissue remodeling by targeting several ECM proteins, including collagen I and fibronectin.Let-7:Let-7 is a family of miRNAs that play a crucial role in regulating gene expression. It was first discovered in C. elegans and has since been identified in various other organisms, including humans. Let-7 has been shown to regulate several cellular processes, including differentiation, proliferation, and apoptosis.In cancer, Let-7 has been shown to act as a tumor suppressor by inhibiting the expression of several targets involved in cell proliferation, migration, and invasion, including CCND2, KRAS, and HMGA2. It has been identified as a potential biomarker for several types of cancer, including lung cancer, breast cancer, and ovarian cancer.In addition to cancer, Let-7 has been implicated in the development and progression of several other diseases, including cardiovascular disease, fibrosis, inflammation, and neurodegenerative diseases. In cardiovascular disease, Let-7 has been shown to regulate several targets involved in vascular smooth muscle cell function and angiogenesis, as well as cellular apoptosis and survival. In fibrosis, Let-7 has been shown to regulate the activity of fibroblasts and myofibroblasts, which are involved in the deposition of ECM and tissue remodeling. In neurodegenerative diseases, Let-7 has been shown to regulate the expression of several genes involved in neuronal differentiation and survival.。

微小RNA—21在乳腺癌细胞中的作用目的：探讨微小RNA（miR）-21在乳腺癌细胞（MCF7）中的作用。

方法：对MCF7细胞转染miR-21，采用免疫组织化学法检测转染后程序性细胞凋亡4（PDCD4）表达；用噻唑蓝（MTT）比色法测转染miR-21后MCF7细胞增殖；流式细胞术检测转染后MCF7细胞凋亡。

结果：经免疫组织化学检测，转染组未见染色，对照组细胞胞质呈棕褐色，转染组PDCD4的表达明显低于对照组，MTT法检测转染组细胞活力增加（P＜0.05）。

转染组的凋亡率为（3.14±0.24）%，明显低于空白组、空质粒组的（8.04±0.02）%、（9.41±0.53）%，差异均有统计学意义（P＜0.05）。

结论：PDCD4是miR-21的靶基因之一，miR-21的高表达可促进乳腺癌的发展。

微小RNA（miRNAs）是一種在真核生物中发现的内生性RNAs，长度大约为21～25个核苷酸，广泛存在于哺乳动物基因组中，具有高度的保守性[1]。

现已明确，miRNA在肿瘤的发生发展中起着关键的调控作用。

笔者通过瞬时转染miR-21于人乳腺癌细胞系MCF7中，检测转染前后细胞的增殖、凋亡及PDCD4的表达，探讨两者的关系及在乳腺癌中的作用机制。

1 材料与方法1.1 材料人乳腺癌细胞系MCF7购自南京科诺生物有限公司、Hyclone胎牛血清、DMEM培养液购自TM公司（宝信生物科技有限公司分装）、真核质粒pEZX-eGFP-miR-21（广州复能基因有限公司）、质粒抽提试剂盒及无内毒素质粒提取试剂盒（北京康为公司）、胶回收试剂盒（TaKaRa公司）、兔PDCD4IgG （Abcam公司）、抗兔抗体（Santa Cruz公司）、0.01 mol/L磷酸盐缓冲液（PBS，实验室配制）、噻唑蓝（MTT）试剂盒（Sigma公司）、膜联蛋白V（Annexin V）细胞凋亡检测试剂盒（凯基公司）。

MicroRNA—21相关靶基因的研究进展MicroRNA是一类非编码小分子RNA，表达于机体的各个组织和器官，主要通过与相关靶基因结合在转录后水平负性调控约60%的人类基因[1]。

其中，miRNA-21在心脑血管、肝脏、肺脏、肾脏等多种疾病中异常表达，明确其所调控的靶基因对阐明miRNA-21的功能及在各种生命过程和疾病发生机制中的作用非常关键。

从而确定miRNA与靶基因的对应关系。

这种方法可本文就目前国内外关于miRNA-21靶基因的研究进展做一综述。

1 实验证实的miR-21靶基因1.1 PTEN 目前研究证明了miRNA是通过与PTEN的3’ UTR端直接结合而抑制其表达[2]。

Ou等分别通过上调及敲低miR-21在鼻咽癌CNE1和CNE2细胞系中的表达水平，发现miR-21可诱导鼻咽癌细胞生长并抑制细胞凋亡；在创伤性脑损伤体外实验中，Wang等证实了miR-21可通过PTEN/Akt信号通路，调节其下游凋亡相关蛋白Caspase-3，Caspase-9，Bcl-2和Bax的表达水平来减少神经元细胞的凋亡，提供了新的创伤性脑损伤神经元凋亡的分子机制，并且提示miR-21可能为其治疗的潜在靶点。

1.2 PDCD4 Angelo Ferraro等在一组结肠肿瘤标本研究中，对miR-21、ITGβ4、PDCD4定量PCR数据集进行ROC曲线分析，结果显示，miR-21表达水平增高、ITGβ4、PDCD4表达水平降低，且三基因组合能够预测结直肠癌的转移[3]。

在宫颈癌hela细胞中转染miRNA21抑制剂后，检测到细胞中PDCD4表达明显上升，进一步研究证实miRNA-21上存在一个与PDCD4 mRNA 3’ UTR相结合的位点，抑制miRNA-21可导致PDCD4的表达上调。

1.3原肌球蛋白1 TPM1 Wang.M证明TPM1 mRNA 3’-UTR是miR-21的直接作用靶点，miR-21通过TPM1来调节血管平滑肌细胞的功能。