MiR-21 induced angiogenesis through AKT and ERK activation and HIF-1α expression

MicroRNAs (miRNAs) are endogenous, small noncoding RNAs that play important roles in various cellular functions and tumor development. Recent studies have indicated that miR-21 is one of the important miRNAs associated with tumor growth and metastasis, but the role and molecular mechanism of miR-21 in regulating tumor angiogenesis remain to be elucidated. In this study, miR-21 was overexpressed by transfecting pre-miR-21 into human prostate cancer cells and tumor angiogenesis was assayed using chicken chorioallantoic membrane (CAM). We found that overexpression of miR-21 in DU145 cells increased the expression of HIF-1α and VEGF, and induced tumor angiogenesis. AKT and extracellular regulated kinases (ERK) 1/2 are activated by miR-21. Inhibition of miR-21 by the antigomir blocked this process. Overexpression of the miR-21 target, PTEN, also inhibited tumor angiogenesis by partially inactivating AKT and ERK and decreasing the expression of HIF-1 and VEGF. The AKT and ERK inhibitors, LY294002 and U0126, suppressed HIF-1α and VEGF expression and angiogenesis. Moreover, inhibition of HIF-1α expression alone abolished miR-21-inducing tumor angiogenesis, indicating that HIF-1α is required for miR-21-upregulated angiogenesis. Therefore, we demonstrate that miR-21 induces tumor angiogenesis through targeting PTEN, leading to activate AKT and ERK1/2 signaling pathways, and thereby enhancing HIF-1α and VEGF expression; HIF-1α is a key downstream target of miR-21 in regulating tumor angiogenesis.     

MiR-103功能的研究进展

MiRNAs是一类非编码的小分子RNA,主要通过与靶基因3’UTR结合来调控基因的表达。MiR-103作为miRNA家族中的重要一员,不仅在发挥生物学功能过程中扮演着重要角色,还参与了包括肿瘤在内的多种疾病的致病机制。该文对miR-103的近期研究成果,尤其是其在多种疾病中的功能作一综述,并指出其具有重要的诊断和治疗潜能。     

MiR-132抑制肿瘤转移

肿瘤转移是造成癌症难以根治的重要原因之一.近年来越来越多的研究发现,miRNA在肿瘤转移过程中发挥了直接或间接的作用.本研究的目标是找到一种特异性的肿瘤转移相关miRNA,能够作为抑制肿瘤转移的潜在靶标.miR-132是一类与炎症、血管生长、中枢神经系统相关的miRNA,至今还没有研究证明其与肿瘤转移相关.为了验证miR-132与肿瘤迁移的相关性,本研究将miR-132转染入高迁移乳腺癌细胞系MDA-MB-231细胞中,检测细胞迁移率的变化.实验发现miR-132能够抑制MDA-MB-231细胞的迁移.为了进一步揭示miR-132抑制细胞迁移的可能机制,本研究通过生物信息学手段寻找并鉴定了3种可能与肿瘤转移相关的miR-132的靶基因,它们分别是CHIP(STUB1)、G3BP1、G3BP2.分别比对MCF7与MDA-MB-231细胞,及转染miR-132和对照组MDA-MB-231细胞中以上3种基因的表达差异,我们发现G3BP1、G3BP2可能参与miR-132对肿瘤转移的调控.本研究首次报道miR-132与肿瘤转移的关系,并揭示了miR-132调节肿瘤转移的可能机制,说明了miR-132具有作为特异性抑制肿瘤转移靶标的潜力,为抑制肿瘤转移提供一个新的靶点.     

MiR-133与恶性肿瘤关系的研究进展

微小Rn A-133(micro Rn A-133,mi R-133)是一种在骨骼肌和心肌特异表达的非编码小Rn A,其在心肌肥大等多种肌源性疾病中发挥重要作用。近年研究发现,多种肿瘤组织存在mi R-133的表达紊乱,其通过转录后抑制靶基因,如EGFR、i GF-1R、MMPs等的表达参与肿瘤细胞的增殖、凋亡、侵袭和转移等多种病理过程,并与肿瘤的发生发展密切相关。了解mi R-133的表达、调控及其在肿瘤等疾病中的作用及机制,可为其进一步的临床应用奠定基础。现就mi R-133与恶性肿瘤关系的研究进展进行综述。     

MiR-203 及其调控机制的研究进展

MicroRNA(miRNA)是一种长18-25个碱基的单链非编码RNA,其广泛参与机体众多病理、生理过程。MiR-203是一种上皮组织特异性表达的miRNA。研究发现miR-203在皮肤发育、皮肤相关疾病、上皮组织肿瘤等病理、生理过程中发挥重要调控作用。一些疾病的研究还发现了miR-203与表观遗传学机制的相互作用,而miR-203调控机制的研究集中在P63、SOCS-3及相关的信号通路等方面。     

MiR-218 regulated cardiomyocyte differentiation and migration in mouse embryonic stem cells by targeting PDGFRα

MicroRNAs (miRNAs) have been identified as key players in cardiogenesis and heart pathophysiological processes. However, many miRNAs are still not recognized for their roles in cardiomyocytes differentiation. In this study, we evaluated the effects of microRNA-218 (miR-218) in cardiomyocyte differentiation of the mouse embryonic stem cells (ESCs) in vitro. The percentage of the beating embryoid bodies (EBs) in miR-218 mimic-treated cells was reduced to 32% compared with miR-218 mimic negative control (56%) on day 5 + 3. The amplitude of the intracellular Ca²⁺ transients in the cardiomyocytes derived from ESCs was reduced upon miR-218 overexpression, followed by the decreased calcium-related proteins and cell junction proteins expressions. Besides, miR-218 expression in ESCs was related to the directional spreading ability of EBs during differentiation. The increased expression of miR-218 could promote the migration of ESCs in vitro, while the decreased expression of miR-218 could inhibit the migration by the transwell experiment. Meanwhile, miR-218 could regulate cell migration–related proteins Cdc42 and Rac1. Platelet-derived growth factor receptor α (PDGFRα) was further confirmed to be a direct target of miR-218 both physically and functionally by dual-luciferase reporter assay. Our data further described that overexpression of PDGFRα rescued the miR-218-mediated inhibition of cardiomyocyte differentiation and restored the miR-218-mediated promotion of cell migration. In conclusion, miR-218 was demonstrated to exert an inhibitory function and promoted cell migration via targeting PDGFRα during cardiomyocyte differentiation from ESCs. The current study revealed the role of miR-218 and may provide an important hint for cardiomyocyte differentiation of ESCs and induced pluripotent stem cells.     

MiR-206在骨骼肌发育中的功能

微RNA(microRNA,miRNA)是一类在分子进化中十分保守的非编码RNA,长度约22个核苷酸,一般情况下它在转录后水平抑制基因表达。miRNA在细胞增殖、分化、凋亡等诸多生理过程中发挥着重要作用。有些miRNA具有组织特异性表达,其中miR-206是目前发现的唯一在骨骼肌中特异表达的miRNA,它在调节骨骼肌发生过程中扮演重要角色。miR-206表达异常与一些肌肉相关疾病如肌肉营养不良、肌萎缩性侧索硬化症等有关。此外,在Texel羊中,myostatin基因的一个点突变就产生了一个miR-206和miR-1的靶点,抑制了myostain基因的表达,从而产生了双肌表型。因此,miR-206有可能成为治疗肌肉相关疾病和畜禽改良育种的重要候选分子。     

MiR-711的表达和功能研究进展

microRNAs是近年来的研究热点之一,芯片技术的运用,使得大量microRNAs作为潜在的疾病干预靶点被筛选出来。miR-711便是其中之一。研究结果显示,miR-711在心血管系统疾病、多种肿瘤以及肿瘤细胞外泌体、急性肝脑脏器损伤、炎症和内分泌疾病中表达水平发生显著改变,参与了包括细胞凋亡,肿瘤增殖,心肌纤维化和炎症反应等功能。但其中机制尚不完全清楚。本文对miR-711的表达特点和调控途径进行总结,对其在多个系统、多种疾病中的研究进展进行综述,为进一步深入研究miR-711的功能和作用机制提供线索。     

Elevated MiR-222-3p Promotes Proliferation and Invasion of Endometrial Carcinoma via Targeting ERα

MicroRNAs play key roles in tumor proliferation and invasion. Here we show distinct expression of miR-222-3p between ERα-positive and ERα-negative endometrial carcinoma (EC) cell lines and primary tumors, and investigation of its relationship with ERα and other clinical parameters. In vitro, the function of miR-222-3p was examined in RL95-2 and AN3CA cell lines. MiR-222-3p expression was negatively correlated with ERα. Over-expressed miR-222-3p in RL95-2 cells promoted cell proliferation, enhanced invasiveness and induced a G1 to S phase shift in cell cycle. Furthermore, the miR-222-3p inhibitor decreased the activity of AN3CA cells to proliferate and invade. In vivo, down-regulated miR-222-3p of AN3CA cells inhibited EC tumor growth in a mouse xenograft model. Additionally, miR-222-3p increased raloxifene resistance through suppressing ERα expression in EC cells. In conclusion, miR-222-3p plays a significant role in the regulation of ERα expression and could be potential targets for restoring ERα expression and responding to antiestrogen therapy in a subset of ECs.     

MiR-138–5p inhibits prostate cancer cell proliferation and chemoresistance by targeting APOBEC3B

Docetaxel is one of the most commonly used drugs in prostate cancer (PCa) chemotherapy, but its therapeutic effect in PCa is usually limited due to its drug resistance. APOBEC3B is a DNA cytosine deaminase that can alter biological processes, including chemoresistance. APOBEC3B is upregulated in various cancers. However, the biological function and underlying regulation of APOBEC3B in PCa remain unclear. In this study, we explored the role of APOBEC3B in PCa chemoresistance and the molecular mechanism of its dysregulated expression. Our results revealed that APOBEC3B was upregulated in PCa docetaxel-resistant cells, while its knockdown significantly repressed cell proliferation and docetaxel resistance of PCa cells. Bioinformatics and luciferase report analysis showed that miR-138–5p targeted APOBEC3B. In addition, miR-138–5p overexpression impeded cell proliferation and docetaxel resistance in PCa, while miR-138–5p inhibitors reversed this process. Further studies showed that upregulation of APOBEC3B expression in docetaxel-resistant cells overexpressing miR-138–5p could desensitize PCa cells to docetaxel treatment. Taken together, miR-138–5p regulates PCa cell proliferation and chemoresistance by targeting the 3′-UTR of APOBEC3B, which may provide novel insights and therapeutic targets for the treatment of PCa.     

MiR-27靶基因的分析及鉴定

MicroRNAs(miRNAs)是一类约20～25nt的小分子核苷酸,在细胞内的多种生物学过程,如细胞增殖、凋亡、生长、分化和代谢等过程中具有重要的功能。已知miR-27在脂肪细胞和肌肉细胞的发育过程中起了重要作用,其在神经细胞中的表达调节至今仍不清楚。在本研究中,通过miRBase和TargetScan数据库分析了miR-27的靶基因,构建了miR-27的真核表达载体,改造了萤火虫荧光素酶和海肾荧光素酶报告载体,将miR-27的靶基因Bmi1的3′-UTR融合到报告载体中,转染神经胶质瘤细胞,利用双荧光素酶检测系统分析荧光素酶的活性。研究发现miR-27a和miR-27b共同的靶基因主要调节发育过程。MiR-27真核表达载体能产生成熟态的miR-27。MiR-27a、miR-27b或miR-27a和miR-27b联合与Bmi1的3′-UTR的正义序列共转染U343细胞能明显降低萤火虫荧光素酶的活性(分别P0.05,P0.05,P0.01),这提示了Bmi1可能为miR-27的靶基因。     

MiR-125b regulates the proliferation and metastasis of triple negative breast cancer cells via the Wnt/β-catenin pathway and EMT

Background/aim: MiR-125b plays an important role in breast cancer. The current study was to explore the expression and function of miR-125b in triple negative breast cancer cells. Materials and methods: The expression of miR-125b in human TNBC samples and cell lines were examined by qRT-PCR. MTT, scratch assays and transwell assays were utilized to observe the proliferation, migration and invasion ability. MiR-125b’s target gene and downstream signaling pathways were investigated by Luciferase Reporter Assays, qRT-PCR, immunofluorescence assays and western bolt. Results: MiR-125b was highly expressed in human TNBC tissues and cell lines. Inhibiting miR-125b expression suppressed the proliferation, cell migration and invasion. The three-prime untranslated region (3´-UTR) of adenomatous polyposis coli (APC) mRNA contains miR-125b binding sites, and inhibiting miR-125b expression suppressed the activity of the intracellular Wnt/β-catenin pathways and EMT. Conclusion: Inhibiting miR-125b regulates the Wnt/β-catenin pathway and EMT to suppress the proliferation and migration of MDA-MB-468 TNBC cells.     

MiR-21靶基因预测和生物信息学分析

为了利用生物信息学方法预测miR-21的靶基因及其功能,为后续研究miR-21及其靶基因在结肠癌发生中的作用机制奠定基础。研究通过miRBase获取并分析多个物种的miR-21的序列特征;应用Target Scan、Pic Tar,miRanda及miRecords 4种在线工具预测miR-21的靶基因,结合已证实的靶基因,对靶基因进行功能注释和信号通路富集分析;通过查找文献,综述miR-21的功能,结合功能注释和信号通路富集分析为进一步研究mir-21在结肠癌发生中的作用提供理论基础。     

MiR-214 Targets β-Catenin Pathway to Suppress Invasion, Stem-Like Traits and Recurrence of Human Hepatocellular Carcinoma

The down-regulation of miR-214 has previously been observed in human hepatocellular carcinoma (HCC). Here, we demonstrated the down-regulation of miR-214 is associated with cell invasion, stem-like traits and early recurrence of HCC. Firstly, we validated the suppression of miR-214 in human HCC by real-time quantitative RT-PCR (qRT-PCR) in 20 paired tumor and non-tumor liver tissues of HCC patients and 10 histologically normal liver tissues from colorectal cancer patients with liver metastases. Further qRT-PCR analysis of 50 HCC tissues from an independent cohort of HCC patients of whom 29 with early recurrent disease (<2 years) and 21 with late recurrent disease demonstrated that the suppression of miR-214 was significantly more suppressed in samples from HCC patients with early recurrent disease compared those from patients with no recurrence. Re-expression of miR-214 significantly suppressed the growth of HCC cells in vitro and reduced their tumorigenicity in vivo. The enhancer of zeste homologue 2 (EZH2) and β-catenin (CTNNB1) was identified as two potential direct downstream targets of miR-214 through bioinformatics analysis and experimentally validated the miRNA-target interactions with a dual-firefly luciferase reporter assay. In corroborate with this, both EZH2 and CTNNB1 are found to be significantly overexpressed in human HCC biopsies. Since EZH2 can regulate CTNNB1, CTNNB1 can also be an indirect target of miR-214 through EZH2. Silencing EZH2 or CTNNB1 expression suppressed the growth and invasion of HCC cells and induced E-cadherin (CDH1), known to inhibit cell invasion and metastasis. Furthermore, the silencing of miR-214 or overexpression of EZH2 increased EpCAM(+) stem-like cells through the activation of CTNNB1. Interestingly, the up-regulation of EZH2, CTNNB1 and the down-regulation of CDH1 in HCC patients correlated with early recurrent disease and can be an independent predictor of poor survival. Therefore, miR-214 can directly or indirectly target CTNNB1 to modulate the β-catenin signaling pathway in HCC.     

MiR-145 inhibits the migration and invasion of papillary thyroid carcinoma cells through NF-κB pathway regulation

Papillary thyroid carcinoma (PTC) is the most prevalent cancer in the endocrine system, and the number of patients diagnosed with PTC has been increasing rapidly in recent years. Previous studies have reported that miR-145 plays an important role in many kinds of cancers, but its function in PTC remains unclear. In this study, we found that compared to paracancerous tissues, the level of miR-145 expression was significantly downregulated in PTC tissues. When miR-145 is overexpressed, migration and invasion of PTC cells were suppressed in vitro. In addition, we found that miR-145 downregulated the nuclear factor-κB (NF-κB) pathway in PTC cells. Taken together, our data suggest that miR-145 functions as a tumor suppressor in PTC with the suppressive effect related to downregulation of the NF-κB pathway.     

MiR-210在缺氧中调控机制的研究进展

MicroRNA(miRNA)是一类包含21-25个核苷酸的单链非编码小RNA.研究表明,miR-210可直接抑制线粒体内铁硫蛋白(Fe-S)的支架蛋白ISCUl/2的表达从而抑制线粒体代谢;miR-210对DNA损伤修复基因-RAD家族有抑制作用,减弱了DNA修复能力;miR-210可以通过调节E2F3、纤维母细胞生长因子受体1(FGFRL1)、同源域基因A1(HOXA1)等阻止细胞增殖,调控细胞周期;缺氧刺激可上调miR-210表达,这对促进血管再生有重要作用.miR-210的表达受缺氧诱导,调控缺氧反应相关基因的表达,提示miR-210有可能成为诊治包括缺血性损伤、肿瘤在内等多种疾病的新靶点.     

MiR-335 Regulates Hif-1α to Reduce Cell Death in Both Mouse Cell Line and Rat Ischemic Models

Hypoxia inducible factor-1α facilitates cellular adaptation to hypoxic conditions. Hence its tight regulation is crucial in hypoxia related diseases such as cerebral ischemia. Changes in hypoxia inducible factor-1α expression upon cerebral ischemia influence the expression of its downstream genes which eventually determines the extent of cellular damage. MicroRNAs are endogenous regulators of gene expression that have rapidly emerged as promising therapeutic targets in several diseases. In this study, we have identified miR-335 as a direct regulator of hypoxia inducible factor-1α and as a potential therapeutic target in cerebral ischemia. MiR-335 and hypoxia inducible factor-1α mRNA showed an inverse expression profile, both in vivo and in vitro ischemic conditions. Given the biphasic nature of hypoxia inducible factor-1α expression during cerebral ischemia, miR-335 mimic was found to reduce infarct volume in the early time (immediately after middle cerebral artery occlusion) of embolic stroke animal models while the miR-335 inhibitor appears to be beneficial at the late time of stroke (24 hrs after middle cerebral artery occlusion). Modulation of hypoxia inducible factor-1α expression by miR-335 also influenced the expression of crucial genes implicated in neurovascular permeability, cell death and maintenance of the blood brain barrier. These concerted effects, resulting in a reduction in infarct volume bring about a beneficial outcome in ischemic stroke.