microRNA-613在恶性肿瘤中的研究进展

微小RNA（microRNA，miRNA）作为一种在恶性肿瘤发生中起到非常重要作用的短链非编码RNA，通过与其靶基因的特异性结合从转录后水平调控肿瘤相关基因的表达。微小RNA-613（microRNA-613，miR-613）定位在人染色体12p13.1，通过对靶基因的调控，参与肿瘤细胞的增殖、分化、凋亡、癌周浸润等恶性进程的调控。近年来研究表明，miR-613在多种肿瘤中异常表达并与肿瘤的临床特征及预后密切相关。鉴于其在恶性肿瘤中的重要作用，miR-613或可成为分子靶向治疗的新靶点。     

miR-32 在恶性肿瘤发生发展中的作用及其机制

[摘要] 微小RNA（microRNA,miRNA）是一种内源性的长度为18~25 个核苷酸的非编码RNA,通过与蛋白质编码基因的mRNA结合来发挥重要的基因调控作用,与恶性肿瘤的发生发展密切相关。miR-32 作为miRNA家族的重要成员,在不同肿瘤中表达水平存在明显差异,因其与恶性肿瘤的相关性及本身表达的正反作用双向性,在miRNA领域受到了更多的关注。近年来研究发现,miR-32 对恶性肿瘤细胞的增殖、迁移与侵袭、自噬和凋亡均有影响。此外,miR-32 与其上游靶基因、肿瘤代谢及临床诊断和治疗也有密切的关系。本文就miR-32 在恶性肿瘤发生发展中的作用及其机制、临床诊治中应用等最新研究进展作一综述。     

miR-21与消化系统肿瘤

microRNA（miRNA）是一类内源性非编码蛋白短链RNA,参与细胞增殖、分化、凋亡等多种重要活动的调控。近来研究发现miRNA具有癌基因或抑癌基因样作用,参与多种恶性肿瘤的演进,是肿瘤发生、发展过程中的重要分子,其中miR-21最受关注。miR-21在消化系统肿瘤如食管癌、胃癌、肝癌、胆管癌、胰腺癌、结直肠癌等的细胞或组织中表达上调,发挥着类似于癌基因的作用。miR-21通过对靶基因的调控,增强了肿瘤细胞的增殖、浸润及转移能力,并与消化系统肿瘤患者的无复发时间与总生存时间密切相关。目前体外研究证实,miR-21抑制物能够提高恶性肿瘤细胞对化疗药物的敏感性,使化疗药物的杀伤肿瘤效果更加明显,而miR-21类似物,可抵消一部分化疗药物的疗效,从而提示抑制miR-21的表达或阻碍miR-21与靶基因的相互作用在消化系统肿瘤的治疗中具有广阔的应用前景。本文就miR-21在消化系统肿瘤的调控机制、增殖与凋亡、侵袭、耐药与转移中的作用,及其临床价值作一综述。      

miR-199a在消化系统肿瘤中的相关研究进展

microRNA（miRNA）是一类内源性非编码短链RNA。研究发现miRNA具有癌基因或抑癌基因样作用,参与多种恶性肿瘤的演进,是肿瘤发生、发展过程中的重要分子,其中miR-199a最受关注。miR-199a在消化系统肿瘤中表达上调,发挥着类似于癌基因的作用。miR-199a通过对靶基因的调控,增强肿瘤细胞的增殖、浸润及转移能力,且与消化系统肿瘤患者的无复发生存时间与总生存时间密切相关。体外研究证实,抑制miR-199a表达或阻碍其与靶基因的相互作用在消化系统肿瘤的治疗中具有广阔的应用前景。本文就miR-199a在消化系统肿瘤的调控机制、增殖与凋亡、侵袭、耐药与转移中的 作用,及其临床价值作一综述。     

缺氧相关的miRNA-210在肿瘤中的研究进展

肿瘤组织失控性增殖及其内部新生血管网的相对不足导致氧气供应不足,低氧是肿瘤微环境的重要特征,低氧环境可激活肿瘤细胞中低氧诱导因子（hypoxia-inducible factors, HIFs）的表达并诱导一系列miRNAs（microRNAs, miRs）含量发生变化。miRNA是一种小的、非编码RNA,可和mRNA3’端非编码区结合,在转录后水平调节基因的表达,miR-210作为最主要的HIFs诱导表达的miRNA,参与肿瘤细胞多种生命活动,如肿瘤细胞线粒体代谢、血管形成、细胞周期调节、DNA断裂修复等;miR-210在大部分肿瘤患者的血清及肿瘤组织中高表达,且miR-210的表达水平与不良预后呈正相关,故miR-210可用于肿瘤的筛查、诊断和预测患者预后;随着对miR-210下游靶基因的深入研究,针对miR-210细胞信号转导通路的靶向治疗可为恶性肿瘤的治疗提供更广阔的前景。     

miR-21与肿瘤

MicroRNA（miRNA）是一类具有调控功能的小分子非编码RNA,主要参与基因转录后水平的调控,对生物体的生长、发育、衰老和死亡等生命过程都有着重要的作用。近年来,大量研究结果表明,许多miRNA可作为原癌基因或者抑癌基因,在肿瘤的发生和发展中扮演着重要的角色,其中miR-21最受人重视。大量实验证明在多种肿瘤细胞中,miR-21的表达均出现显著异常,揭示miR-21作为一个致癌miRNA,在多种肿瘤的发生和发展中起着重要的作用。本文综述了miR-21在肿瘤细胞中调控的靶基因及其功能,以及miR-21自身的表达调控机制研究进展,这将为miR-21在肿瘤的诊断、治疗和预后判断中的应用提供重要资料。     

miR-335、Survivin表达及对乳腺癌术后患者预后评估的价值

目的:探讨微小RNA335(microRNA-335,miR-335)和Survivin在乳腺癌患者组织中表达情况以及其表达水平对患者预后的影响。方法:收集我院2010年2月1日至2014年2月1日乳腺癌患者标本140例,通过实时免疫荧光定量聚合酶链反应（RT-PCR)法检测所有乳腺癌组织、癌旁组织中miR-335的表达情况;采用免疫组织化学方法检测癌组织、癌旁组织中Survivin的表达情况。应用SPSS 16.0软件对比miR-335、Survivin与乳腺癌患者临床病理之间的关系,以及对患者预后的影响。结果:miR-335在癌组织中的表达明显低于癌旁组织(25.36% vs 82.51%,P=0.003),Survivin在癌组织中的表达明显高于癌旁组织(80.13% vs 26.73%,P=0.001 6),miR-335在乳腺癌组织中的表达水平与肿瘤病理类型、分化程度、临床分期呈负相关（r=-0.47,P=0.02;r=-0.31,P=0.03;r=-0.75,P=0.04),而Survivin在乳腺癌组织中的表达水平与肿瘤病理类型、分化程度、临床分期呈正相关（r=0.52,P=0.03;r=0.63,P=0.01;r=0.37,P=0.03)。COX回归模型发现乳腺癌患者肿瘤TNM分期、淋巴结转移、分化程度、病理类型、ER、PR、Her-2、miR-335、Survivin表达均为影响乳腺癌患者PFS的因素。miR-335对于乳腺癌患者术后3年 PFS、OS预测曲线下面积分别为83.4%、78.6%(P<0.01);Survivin 对于乳腺癌患者术后3年PFS、OS预测曲线下面积分别为79.5%、70.6%(P<0.01)。差异有统计学意义（P<0.01,P<0.01)。结论:miR-335、Survivin在乳腺癌组织和癌旁正常组织中的表达存在明显差异,miR-335高表达、Survivin低表达时,提示乳腺癌患者手术预后良好。     

miRNA-335基因启动子区甲基化与胃癌细胞不良生物学行为的关系

目的:探讨miR-335基因启动子区异常甲基化状态对胃癌细胞系中miR-335表达水平的影响,以及miR-335基因启动子区甲基化状态对胃癌细胞侵袭,迁移,以及增殖能力的影响。方法:1株永生化胃黏膜上皮细胞系(GES-1)和4株胃癌细胞系(SGC-7901,MKN-45,BGC-823和AGS)。实时荧光定量PCR(qRT-PCR)检测胃癌细胞株miR-335及CRKL的表达水平。甲基化特异性PCR(MSP)方法检测胃癌细胞株miR-335的基因启动子区甲基化状态。应用MTT方法检测恢复miR-335表达对胃癌细胞增殖能力的影响,Transwell侵袭迁移实验及划痕愈合实验分析恢复miR-335表达对胃癌细胞系侵袭及迁移能力的影响。结果:MSP实验结果表明,MKN-45、SGC-7901和BGC-823细胞系均存在基因启动子区异常的高甲基化状态,AGS细胞系基因启动子区亦呈部分高甲基化状态。去甲基药物5-aza-2′-deoxycytidine处理后胃癌细胞miR-335的表达水平可升高2~3倍。Transwell侵袭迁移实验及划痕愈合实验表明miR-335表达水平恢复后SGC-7901细胞的侵袭和迁移能力明显降低。MTT实验结果表明5-aza-2′-deoxycytidine处理后的SGC-7901细胞系与对照组相比,增殖能力显著降低。结论:miR-335启动子区的异常高甲基化状态抑制了miR-335在胃癌细胞系中的表达,恢复miR-335的表达水平可以抑制胃癌细胞的增殖,迁移和侵袭能力。miR-335为胃癌的肿瘤抑制因子。     

MicroRNA-335的表遗传学调控机制及其与胃癌患者临床病理特征的关系

目的:探索miR-335基因启动子区甲基化状态对胃癌组织及细胞系中miR-335表达水平的影响,以及miR-335基因启动子区甲基化状态与胃癌患者临床病理特征以及预后的关系。方法:收集2012年7月1日-2014年7月1日中国医科大学附属第四医院就诊经病理诊断为原发性胃癌并行根治性手术的108例新鲜胃癌组织及配对癌旁组织,1株永生化的胃黏膜上皮细胞系(GES-1)和4株胃癌细胞系(SGC-7901、MKN-45、BGC-823和AGS)。实时荧光定量PCR(qRT-PCR)检测胃癌细胞株及108例胃癌患者肿瘤组织中miR-335的表达水平。甲基化特异性PCR(MSP)方法检测胃癌细胞系及胃癌患者肿瘤组织中miR-335的基因启动子区甲基化状态。分析miR-335基因启动子区甲基化状态对胃癌患者临床病理特征的影响。结果:qRT-PCR检测结果显示,miR-335在胃癌细胞株中的表达水平显著低于正常胃黏膜上皮细胞株GES-1［MKN-45,0.154±0.016-fold(P＜0.01);SGC-7901,0.138±0.013-fold(P＜0.01);BGC-823,0.432±0.076-fold(P＜0.01);AGS,0.749±0.072-fold(P=0.01)］。miR-335在108例胃癌组织中的表达水平较癌旁组织存在明显下降,差异显著（P＜0.001）。MSP的实验结果表明,MKN-45、SGC-7901、AGS和BGC-823细胞株均存在基因启动子区异常高甲基化状态。miR-335基因启动子区的高甲基化状态与肿瘤大小(P=0.004)、淋巴结转移(P=0.046)、淋巴管浸润(P=0.001) 和miR-335 低表达 (P<0.001) 显著相关。结论:miR-335启动子区的高甲基化状态抑制了miR-335在胃癌细胞中的表达,miR-335的基因启动子区异常高甲基化状态与胃癌患者的肿瘤大小、淋巴结转移以及淋巴管浸润显著相关。     

miR-485-5p在恶性肿瘤中的研究进展

MicroRNAs(miRNAs)是一类长度约22个核苷酸的非编码RNA,在基因表达调控中,参与多种重要的生理和病理过程。miRNAs能够特异性结合靶基因序列,抑制基因的转录或翻译,从而抑制基因在转录或转录后水平上的表达。miRNAs作为肿瘤抑制因子或促进因子在癌症发生发展中经常失调。最近的研究发现miR-485-5p在多种癌症中表达下调,并调控肿瘤细胞生长、增殖、侵袭和迁移。miR-485-5p在肿瘤诊断、治疗及预后相关方面可作为具有潜在价值的肿瘤标志物,并有望成为临床肿瘤靶向治疗的新的治疗靶点。本文围绕miR-485-5p在肝癌、胃癌、乳腺癌及其他恶性肿瘤中的研究进展展开综述并对其未来应用和发展进行展望。     

Breast cancer metastasis: a microRNA story

MicroRNAs (miRNAs) are small noncoding RNAs with regulatory functions, which play an important role in breast cancer. Several studies have shown that miRNAs can act either as tumor suppressors or as oncogenes, and that measurement of miRNA expression in malignancies may have diagnostic and prognostic implications. This article highlights a series of three recent studies that prove the involvement of miRNAs in breast cancer metastases. The first proves that miR-10b indirectly activates the pro-metastatic gene RHOC by suppressing HOXD10, thus leading to tumor invasion and metastasis. The second proves that miR-373 and miR-520c can also promote tumor invasion and metastasis, at least in part by regulating the gene CD44. The third identifies miR-335, miR-206, and miR-126 as suppressors of breast cancer metastasis. Loss of miR-335 leads to the activation of SOX4 and TNC (encoding tenascin C), which are responsible for the acquisition of metastatic properties. Altogether, these remarkable findings are important for our understanding of malignant transformation in the breast and may have implications for the management of patients with advanced breast cancer. The use of miRNAs as anticancer therapeutic agents is promising, and such fine molecular studies certainly help in bringing miRNAs closer to clinical practice.     

Methylation-associated silencing of MicroRNA-335 contributes tumor cell invasion and migration by interacting with RASA1 in gastric cancer

MicroRNAs (miRNAs) are small non-coding RNAs that function as endogenous silencers of target genes, previous studies have shown that miR-335 play an important role in suppressing metastasis and migration in human cancer including gastric cancer (GC). However, the mechanisms which result in aberrant expression of miR-335 in GC are still unknown. Recent studies have shown that the silencing of some miRNAs is associated with DNA hypermethylation. In this study, we find the promoter of miR-335 we embedded in CpG island by accessing to bioinformatics data and the low expression of miR-335 in 5 gastric cell lines can be restored by 5-aza-2’-deoxycytidine (5-Aza-dC) treatment. So we postulated that the miR-335 genes undergo epigenetic inactivation in GC. Subsequently, in GC cells and tissues, we performed quantitative real-time PCR (RTQ-PCR) to assess the expression of miR-335, and methylation-specific PCR (MSP) and bisulfite sequence-PCR (BSP) to evaluate the DNA methylation status in the CpG islands upstream of MiR-335. The result showed that the expression of miR-335 was significantly reduce in gastric cancer cell lines and tumor tissues compared to matched normal gastric tissues, and cell lines, and which is inverse correlation with DNA hypermethylation of miR-335 both in GC cells lines and tissues, but not in normal tissues. In addition, we found that the lower miR-335 expression induced by abnormal methylation may be mainly involved in gastric cell invasion and metastasis in GC tissues. No statistical significance was found about miR-335 expression and methylation level between healthy individuals with and without H. pylori (HP) infection. Finally, we carry out miRNA transfection, RTQ-PCR and western blot assay to find the RAS p21 protein activator (GTPase activating protein) 1 (RASA1) may be the possible target genes which lead to the gastric cell invasion and metastasis, furthermore, the re-expression of endogenous miR-335 by 5-Aza-dC treatment can exert effects similar to exogenous miRNAs transfection. Taken together, our results suggest that miR-335 may be silenced by promoter hypermethylation and play important roles in gastric cell invasion and metastasis through its target genes, such as RASA1. Its methylation level might be a predictive epigenetic marker of GC and remodeling on the expression by demethylation can provided a potential therapeutic strategy.     

MicroRNA signature in the chemoprevention of functionally-enriched stem and progenitor pools (FESPP) by Active Hexose Correlated Compound (AHCC)

Purpose: Many breast cancer patients use natural compounds in their battle against breast cancer. Active Hexose Correlated Compound (AHCC®) is a cultured mushroom mycelium extract shown to favorably modulate the immune system and alleviate cancer burden. Cancer Stem cells (CSCs) are a subset of highly tumorigenic cancer cells that are thought to be responsible for recurrence. CSCs can be epigenetically regulated by microRNAs (miRNAs). We hypothesized that AHCC may influence CSCs by modulating tumor-suppressor or oncogenic miRNAs. Methods: Functionally-enriched stem and progenitor pools (FESPP) were isolated in the form of mammospheres from MDA-MB-231, MCF-7, and 4T1 cells, exposed to AHCC in both regular and primary culture from Balb/c mice, and analyzed by visual counting and flow cytometry. Cell motility was also observed in MDA-MB-231 cells. Profiling and RT-qPCR were performed to determine AHCC influence on miRNAs in MDA-MB-231 mammospheres. Additionally, Balb/c mice were orally gavaged with AHCC, and tumor growth parameters and miR-335 expression were analyzed. MDA-MB-231 cells were transfected with miR-335 and analyzed by western blot. Results: We demonstrated that AHCC reduced mammosphere growth in three cell lines and in primary culture, prevented cell migration, and upregulated miR-335 expression in MDA-MB-231 cells and mouse tumor samples. Among the differentially regulated miRNAs in CSCs, we focused on tumor suppressor miR-335, known to target extracellular matrix protein Tenascin C (TNC). TNC is involved in CSC immune evasion pathways. In MDA-MB-231, inhibition of miR-335 increased TNC protein expression. Conclusions: These results support that AHCC limits FESPP growth, partly by targeting miRNA pathways.     

Genetic variants within miR-126 and miR-335 are not associated with breast cancer risk

MicroRNAs (miRNAs) are 20-22 nt non-coding RNAs which promote the degradation of target mRNAs or repression of the translation of mRNAs by sequence specific targeting. Many miRNAs are considered as oncogenes or tumor suppressors. MiR-126 and miR-335 play roles in the suppression of breast cancer metastasis by inhibiting tumor growth, proliferation, and cell invasion. The effects of SNPs within the two miRNAs are still unknown. In our study, we analyzed two SNPs, rs4636297 within miR-126 and rs41272366 within miR-335, in three study populations for a putative association with breast cancer risk. We compared the genotype and allele frequencies of rs4636297 and rs41272366 in 2854 cases versus 3188 controls of the three study populations independently and combined. None of the performed analyses showed statistically significant results. In conclusion, our data suggest that the two genetic variants within miR-126 and miR-335 are not associated with breast cancer risk.     

MicroRNA与DNA甲基化相互调节机制在肝细胞癌中的研究进展

肝细胞癌是原发性肝癌的主要类型,也是人类恶性程度较高的肿瘤之一,其发病机制至今尚未完全阐明.表观遗传学机制在肿瘤的发生、发展中起重要作用,DNA甲基化和微小RNA (microRNA,miRNA)的调控机制属于表观遗传学的研究范畴.研究表明,DNA甲基化及miRNA在肝细胞癌的形成中分别或协同发挥着重要作用,miRNA是一类在转录后水平调节基因表达的非编码短链RNA.研究表明,DNA甲基化和组蛋白修饰不仅可以调节蛋白编码基因的表达,而且可以调节miRNA的表达.在肝细胞癌中,一些异常表达的miRNAs(如miR-125b、miR-1-1、miR-124、miR-203和miR-191)是通过表观遗传学机制调控的.另外,在肝细胞癌中还发现了一类miRNAs通过调控表观遗传学通路中关键分子来改变整个基因组的表观遗传学状态.本文就DNA甲基化和miRNA之间复杂的相互调节机制在肝细胞癌发生和发展中的研究进展进行综述.     

miR-218与宫颈癌关系的研究进展(英文)

MicroRNAs (miRNAs) are small endogenous non-coding RNAs which can specifically silence gene expression, and thereby alter cell and organism phenotype. Deregulation of miRNA expression has been discovered in a variety of tumors and it is now clear that they contribute to cancer development and progression. Previous studies have indicated that miRNAs are involved in developmental timing, cell proliferation, apoptosis, morphogenesis [1] , antiviral defense [2] , and tumorigenesis [3] . In cancer pathways, altered expression of tumor suppressive or oncogenic miRNAs can disrupt regulatory mechanisms normal. Altered miRNAs expression patterns have been observed in a variety of diseased tissues. Cervical cancer is the most common malignant tumor in female reproductive tract. Recently more and more study showed a large number of miRNAs were down-regulated or up-regulated in cervical cancer. Recent data revealed that miRNA-218 (miR-218) played important roles in tumor initiation and development. This review focuses on analysis of miR-218 and will provide some insight into the progress of cervical cancer.     

Analysis of miR-205 and miR-155 expression in the blood of breast cancer patients

The purpose of this study was to identify and validate circulating microRNAs (miRNAs) in human plasma for use as breast cancer (BC) biomarkers and to analyze their relationship to clinicopathologic features and its preliminary biological function. Genome-wide expression profiling of miRNAs in BC was investigated by microarray analysis. miR-155 was up-regulated greater than two-fold in BC compared with Normal Adjacent Tissue (NAT), whereas let-7b, miR-381, miR-10b, miR-125a-5p, miR-335, miR-205 and miR-145 were down- regulated greater than two-fold. Our hypothesis was that circulating miRNAs are also present and differentially expressed in the serum of BC patients compared to controls. Using real-time PCR (RT-PCR), we analyzed miR-205 and miR-155 in archived serum from 30 participants, 20 with breast cancer and 10 healthy people. miR-205 was down-regulated in BC patient serum while miR-155 was up-regulated. Furthermore, we analyzed the relationship between the expression levels of these two miRNAs and the clinicopathologic parameters of BC patients. High expression of miR155 was associated with clinical stage, molecular type, Ki-67 and p53 in BC patients (P<0.05). By contrast, we found no significant correlation between miR-205 and BC patient clinicopathologic parameters. Functional analysis showed that ectopic expression of miR-205 significantly inhibits cell proliferation and promotes apoptosis. miR-205 was down-regulated and miR-155 was up-regulated in BC patient serum. miR-155 was positive correlated with clinical stage and ki-67 and negatively correlated with p53 status.