miR-145通过下调OCT4基因抑制肺腺癌干细胞增殖

背景与目的 miR-145是通过miRNA芯片及qPCR验证筛选出的一种潜在肺癌"保护性"miRNA。本研究旨在探讨miR-145与肺癌干细胞之间的关系及分子机制。方法 miRNA芯片对肺腺癌患者瘤旁和正常组织进行表达谱分析;生物信息学软件预测miR-145潜在的靶基因;脂质体2000介导转染miR-145模拟物和阻遏物进入A549细胞株;实时定量PCR检测miR-145表达水平;Western blot检测OCT4蛋白水平;双荧光素酶报告基因验证miR-145是否作用于OCT4mRNA的3’UTR区预测靶位;细胞增殖实验检测miR-145对于A549细胞生长的作用;流式细胞术检测干细胞表型CD133+的表达。结果在肺腺癌组织中miR-145表达明显低于瘤旁正常组织;miRanda软件预测OCT4是miR-145潜在靶基因;与对照组相比,miR-145模拟物组和阻遏物组miR-145表达分别明显上调和下调;miR-145对A549细胞的生长有双向调节作用,过表达miR-145抑制细胞生长;过表达miR-145可明显降低OCT4蛋白水平及干细胞表型CD133百分比,而抑制miR-145表达则明显增加OCT4蛋白水平及CD133百分比。双荧光素酶报告基因检测证明miR-145可作用于OCT4mRNA的3’UTR区预测靶位。结论 miR-145可通过下调OCT4基因表达抑制A549肺腺癌细胞株中干细胞的增殖,是一种潜在的肺癌"保护性"miRNA。     

p53通过促进miR-145的表达抑制肺腺癌A549细胞的干细胞特性

目的： 探讨P53 抑制肺腺癌A549细胞干细胞特性及其机制。方法： 收集2014年3月至2015年12月解放军第85医院胸外科手术切除的30例非小细胞肺癌（non-small cell lung carcinoma, NSCLC）患者癌组织及癌旁组织,采用Real-time PCR检测NSCLC组织和癌旁组织中miR-145的表达。构建人P53 基因的真核表达载体（pcDNA3.1-P53）和突变载体\[pcDNA3.1-P53 R273H(CGT-CAT)\],设计靶向P53基因的siRNA,分别转染A549细胞;细胞分为对照转染组（Vector或NC-siRNA）和实验组（Flag-P53或P53-siRNA）;Western blotting检测P53蛋白过表达和干扰效率,Real-time PCR检测OCT4和miR-145的表达,荧光双报告基因和Western blotting技术检测证实A549细胞中干细胞多能性调节基因（OCT4）为miR-145的靶标分子。结果： NSCLC组织中miR-145的表达水平明显低于癌旁组织\[(2.31±0.13) vs (3.51±0.27),P<0.01\];P53明显促进A549细胞中miR-145的表达\[(1.84±0.14) vs (1.00±0.00),P<0.01\];miR-145 mimics显著抑制A549细胞中pGL3-OCT4-3′-UTR活性(P<001)和OCT4蛋白表达水平(P<0.05),而转染miR-145抑制剂可进一步增加OCT4表达水平,且逆转P53对A549细胞的干细胞特性的抑制作用。结论：P53通过促进miR-145表达下调OCT4表达,进而明显抑制A549细胞的干细胞特性,该结果为肺腺癌的临床诊断和治疗提供了新途径。     

miR-145通过靶向抑制SMAD3的表达抑制非小细胞肺癌细胞侵袭能力

目的:探讨miR-145靶向调控SMAD3的表达对非小细胞肺癌细胞侵袭能力的影响。方法:采用qRT-PCR检测miR-145和SMAD3在30例非小细胞肺癌组织和癌旁组织中的表达水平并分析其相关性。利用靶基因预测网站预测miR-145的潜在靶基因SMAD3,利用双荧光素酶报告基因实验验证。利用细胞转染实验对非小细胞肺癌A549细胞进行了miR-145 mimics、miR-145 inhibitor、siRNA SMAD3及其相关对照的细胞转染,采用Transwell实验检测转染后A549细胞侵袭能力的变化。使用Western blot检测上调或下调miR-145表达对A549细胞中SMAD3蛋白表达的影响。结果:qRT-PCR结果显示,非小细胞肺癌组织中miR-145低表达,SMAD3高表达,且两者表达水平呈负相关。靶基因预测及验证实验结果显示miR-145可以与SMAD3 的 3'-UTR特异性结合,SMAD3是miR-145的靶基因。Western blot 结果显示,转染miR-145 mimics可以显著降低SMAD3蛋白的表达水平（P<0.001）,转染miR-145 inhibitor则显著提高SMAD3蛋白的表达水平（P<0.01）。Transwell体外侵袭实验结果显示,与对照组相比,转染miR-145 mimic显著降低了A549细胞的侵袭能力（P<0.001）,转染miR-145 inhibitor显著提高了A549细胞的侵袭能力（P<0.05）;与对照组相比,敲低SMAD3的表达A549细胞的侵袭能力减弱（P<0.001）;与单独敲低SMAD3相比,共同转染siRNA SMAD3和miR-145 mimics A549细胞的侵袭能力减弱（P<0.05）,共同转染siRNA SMAD3和miR-145 inhibitor A549细胞的侵袭能力无显著差异（P>0.05）。结论:miR-145在非小细胞肺癌组织中低表达,miR-145通过靶向抑制SMAD3的表达发挥对非小细胞肺癌细胞侵袭能力的抑制作用,为临床综合治疗提供了新的作用靶点。     

肺癌转移相关microRNA miR-29b的生物信息学分析*

目的: 应用生物信息学分析A549细胞中在CD133阳性低表达的miR-29b的靶基因及其功能,为以miR-29b为靶点的肿瘤研究提供线索。 方法: 利用miRNA PCR芯片筛选A549细胞中CD133阳性和CD133阴性差异表达的miRNA,选用miRecords预测miR-29b的靶基因,合并已证实的靶基因,利用GOEAST和DAVID数据库对所得靶基因进行功能富集分析和信号转导通路富集分析。 结果: A549细胞中与CD133阴性比较,miR-29b在CD133阳性中表达下调。miR-29b靶基因有106个,其靶基因功能富集于结合和细胞外基质形成等作用（P<0.01）;信号转导通路显著富集于JAK-STAT和TGF-β等信号转导通路（P<0.05）。 结论: miR-29b可能与肺癌转移相关,miR-29b的靶基因显著富集在与肿瘤相关的信号通路中。      

miR-145通过靶向AP4对非小细胞肺癌A549细胞迁移侵袭的影响

 目的 探讨miR-145对非小细胞肺癌迁移与侵袭能力的影响及其可能的作用机制。方法 qRTPCR法检测非小细胞肺癌组织中miR-145和激活增强子结合蛋白4（activating enhancer binding protein4, AP4）mRNA的表达。A549细胞转染miR-145 mimic或者AP4 siRNA后，划痕实验与Transwell小室法分别检测A549细胞的迁移与侵袭能力，qRT-PCR法与免疫印迹法（Western blot）检测A549细胞中AP4 mRNA与蛋白表达水平；双荧光素酶报告基因法检测AP4 mRNA与miR-145的关系。结果 与癌旁正常组织相比，非小细胞肺癌组织中miR-145表达明显降低（P<0.05），而AP4 mRNA和蛋白表达均明显升高（均P<0.05）；与对照组相比，转染miR-145 mimic后，A549细胞中miR-145表达明显升高（P<0.05），AP4 mRNA和蛋白水平明显降低（P<0.05）；A549细胞的迁移数与侵袭能力均显著下降（均P<0.05）；双荧光素酶报告基因法验证AP4 mRNA是miR-145的靶基因。A549细胞转染AP4siRNA后，A549细胞的迁移数与侵袭数显著下降（均P<0.05）。结论 上调miR-145能抑制A549细胞的迁移与侵袭能力，可能与其抑制靶基因AP4表达有关。     

miR-133b靶向PKM2基因对肺癌A549干细胞增殖及药物敏感性的影响

背景与目的 已有研究表明miR-133b可抑制肺癌细胞生长,miR-133b表达水平在肺癌组织及患者血清中显著降低,miR-133b通过靶向丙酮酸激酶M2型(pyruvate kinase isozyme type M2,PKM2)基因提高鳞癌细胞的放疗敏感性,但其机制尚未明了.本研究通过提取非小细胞肺癌细胞株A549的CD133+/CD34+干细胞,研究miR-133b对其增殖及顺铂类药物(cisplatin,DDP)敏感性的影响,探讨miR-133b与PKM2基因的关系,以及它们在肺癌干细胞中的作用.方法 使用miRBase和miRNAMap数据库进行miR-133b与PKM2基因的序列比对.应用免疫磁珠分选法从A549细胞中分选出CD133+/CD34+肺癌干细胞,流式细胞仪检测纯度.转染miR-133b进入CD133+/CD34+细胞,qRT-PCR检测验证miR-133b表达情况,CCK8法检测细胞增殖情况;15μg/mL DDP处理转染miR-133b细胞,检测0 h、12 h、24 h、72 h的细胞凋亡情况;采用Western blot检测PKM2蛋白水平的表达.结果 PKM2基因可能为miR-133b的靶基因;流式结果显示CD133+/CD34+细胞的纯度为(92.15+4.27)%.qRT-PCR结果显示,与对照组相比,过表达miR-133b后,miR-133b明显上调,miR-133b抑制表达后,miR-133b明显下调(P<0.05).细胞增殖实验及Western blot结果显示,与对照组相比,miR-133b mimics组细胞的增殖能力显著降低(P<0.05),PKM2蛋白水平明显降低(P<0.05);而抑制miR-133b表达则明显增加细胞的增殖能力及PKM2蛋白水平(P<0.05).DDP处理12 h后miR-133b mimics组细胞的凋亡持续明显高于对照组(P<0.05).miR-133b mimics+DDP组PKM2蛋白的表达明显低于对照组及miR-133b inhibitor组(P<0.05).结论 过表达miR-133b能够通过下调PKM2而抑制肺癌干细胞的生长和增殖,并且可以增强肺癌干细胞对DDP的敏感性.     

miR-203下调Bmi-1基因对肺腺癌细胞侵袭转移的影响

目的 探讨miR-203在肺腺癌中的表达,并分析其与肺腺癌细胞侵袭转移的关系及其分子机制。方法 实时定量PCR检测40例肺腺癌患者肿瘤组织中miR-203的相对表达水平及其与临床病理特征之间的关系;实时定量PCR检测H1650、A549、H1975、SPC-A-1肺腺癌细胞株中miR-203表达水平;生物信息学软件预测miR-203潜在的靶基因;脂质体2000介导miR-203模拟物、Bmi-1基因或Bmi-1 siRNA转染H1975细胞株;Western blotting检测Bmi-1蛋白水平;双荧光素酶报告基因验证miR-203是否作用于Bmi-1 mRNA的3’UTR 区预测靶位;Transwell小室侵袭实验检测H1975细胞株的侵袭转移能力。结果 40例肺腺癌组织中miR-203的相对表达量为0.065±0.013;肺腺癌miR-203表达与淋巴结转移有关,而与其他临床病理参数均无关;miR-203在肺腺癌细胞株H1650、A549、H1975、SPC-A-1中的相对表达量分别为0.280±0.102、0.308±0.168、0.167±0.073和0.287±0.096。生物信息学软件预测Bmi-1是miR-203的潜在靶基因;过表达miR-203可明显降低Bmi-1蛋白表达水平;双荧光素酶报告基因检测证明miR-203可作用于Bmi-1基因mRNA的 3’UTR区预测靶位。过表达miR-203+Bmi-1 siRNA可显著抑制肺腺癌细胞株H1975的侵袭迁移能力;在miR-203过表达的H1975细胞株中同时过表达Bmi-1可恢复其侵袭能力。结论 miR-203可通过下调Bmi-1基因表达抑制H1975肺腺癌细胞株的侵袭转移,是一种潜在抑制转移的miRNA分子。     

非小细胞肺癌顺铂化疗耐药相关微RNA的筛选及鉴定

 目的　探讨肿瘤细胞微RNA（miRNA）对化疗药物敏感性的作用。方法　通过miRNA芯片技术检测顺铂（DDP）耐药细胞株A549／DDP与非耐药细胞株A549的miRNA表达的差异,利用荧光定量聚合酶链反应（PCR）技术验证相应miRNA的表达情况,通过在细胞株中抑制或过表达目标miRNA,研究其对细胞化疗药物敏感性的影响。结果　A549／DDP细胞对DDP的耐药为A549细胞的18倍。A549／DDP细胞与A549细胞存在51个表达水平差异在4倍以上的miRNA,其中24个表达上调,27个表达下调。PCR进一步证实miR-376c、miR-31、miR-29a、miR-221在A549／DDP细胞中显著上调,miR-196a、miR-20a、miR-20b、miR-17、miR-451在A549／DDP细胞中显著下调。在提高A549／DDP细胞中miR-17的表达后,细胞对DDP的敏感度增加了11.7 %,提高miR-451的表达或者抑制miR-29a的表达后,对DDP的敏感度分别下降了15.5 %、12.9 %,抑制miR-376c、miR-31、miR-221或过表达miR-196a、miR-20a、miR-20b均不影响A549／DDP细胞对DDP的敏感度。结论　非小细胞肺癌DDP耐药细胞与非耐药细胞的miRNA表达谱有差异,miRNA参与肺癌化疗耐药,miR-17具有逆转非小细胞肺癌DDP耐药的潜力。     

MicroRNA-145增强非小细胞肺癌细胞对吉非替尼敏感性及其机制探讨

目的:探讨微小RNA-145（microRNA-145，miR-145）对非小细胞肺癌细胞系吉非替尼耐药的作用及其可能的潜在机制。方法:实时荧光定量PCR（Q-PCR）方法检测正常细胞及非小细胞肺癌细胞中miR-145的表达差异；不同时间5 μmol/L吉非替尼干预肺癌细胞SPC-A-1和A549后，Q-PCR检测miR-145表达变化；miR-145 mimics和miR-145 inhibitors分别转染SPC-A-1和A549肺癌细胞后，CCK8检测细胞活力变化;双荧光素酶报告系统检测miR-145与ADAM19的靶向结合；miR-145 mimics转染SPC-A-1和A549肺癌细胞，Western blot检测ADAM19蛋白表达；Western blot检测5 μmol/L吉非替尼干预后，SPC-A-1和A549肺癌细胞中ADAM19蛋白的表达；miR-145 mimics转染SPC-A-1和A549肺癌细胞，再用5 μmol/L吉非替尼干预，Western blot检测ADAM19蛋白的表达；采用siRNA抑制ADAM19表达，再用5 μmol/L吉非替尼干预，CCK8检测细胞活力；采用BALB/C雌性裸鼠皮下接种肿瘤细胞的方法，观察上述效应。结果:Q-PCR结果显示，与正常肺上皮细胞系BEAS-2B相比较，肺癌细胞SPC-A-1和A549中miR-145表达明显降低；5 μmol/L吉非替尼干预SPC-A-1和A549细胞后，miR-145表达显著上调；转染miR-145 mimics后,CCK8结果显示两种细胞细胞活力下降；双荧光素酶报告系统结果显示，miR-145靶向结合ADAM19基因的3'-UTR区；Western blot结果显示，5 μmol/L吉非替尼诱导SPC-A-1和 A549细胞后，两种细胞中ADAM19蛋白表达均降低；miR-145 mimics转染SPC-A-1和A549细胞，之后给予5 μmol/L吉非替尼治疗，ADAM19蛋白表达下调；siRNA抑制SPC-A-1和A549细胞中ADAM19表达，再给予5 μmol/L吉非替尼治疗，CCK8结果显示，两种细胞的细胞活力显著降低；过表达BALB/C雌性裸鼠的miR-145后，显著抑制皮下肿瘤生长，并且增强吉非替尼的抗肿瘤效果。结论:miR-145显著增强肺癌细胞SPC-A-1和A549对吉非替尼的敏感性，其机制可能是通过靶向结合AMDM19基因的3'-UTR区域，从而抑制其表达。miR-145有可能成为治疗非小细胞肺癌吉非替尼耐药的有效靶点。     

非小细胞肺癌耐药细胞株A549/DDP中microRNA表达的初步研究

目的:应用miRNA芯片技术检测非小细胞肺癌(NSCLC)细胞株A549及顺铂(DDP)耐药株A549/DDP miRNAs表达的差异.方法:MTT法检测A549/DDP相对于其亲本细胞A549的耐药性和耐药倍数;分别提取2种细胞的总RNA进行质检;microRNA芯片检测NSCLC细胞株A549及对应的DDP耐药株A549/DDP中miRNA表达差异;采用real-time PCR验证结果.结果:DDP对A549和A549/DDP细胞的IC50值分别为7.47和137.32μmol/L,两者差异有统计学意义(P＜0.01),耐药倍数为18.38倍.microRNA芯片结果显示,耐药株A549/DDP与亲本细胞系A549比较有34条有差异表达的miRNA(19条上调,15条下调)差异比值＞1.5倍或＜0.67倍,P＜0.05;real-time PCR的结果进一步证实miR-21、miR-31和miR-374在A549/DDP中显著上调,而miR-378、miR-886-5p、miR-886-3p和miR-520c-3p在A549/DDP中显著下调.结论:A549/DDP与A549的miRNA的表达谱存在差异,miRNA可能参与NSCLC DDP耐药,为进一步研究miRNA在NSCLCDDP耐药机制中的作用奠定基础.     

miR-145 inhibits tumor growth and metastasis by targeting metadherin in high-grade serous ovarian carcinoma

High-grade serous ovarian carcinoma (HGSOC), the most common and aggressive subtype of epithelial ovarian cancer, is characterized by TP53 mutations and genetic instability. Using miRNA profiling analysis, we found that miR-145, a p53 regulated miRNA, was frequently down-regulated in HGSOC. miR-145 down-regulation was further validated in a large cohort of HGSOCs by qPCR. Overexpression of miR-145 in ovarian cancer cells significantly suppressed proliferation, migration and invasion in vitro and inhibited tumor growth and metastasis in vivo. Metadherin (MTDH) was subsequently identified as a direct target of miR-145, and was found to be significantly up-regulated in HGSOC. Furthermore, overexpression of MTDH rescued the inhibitory effects of miR-145 in ovarian cancer cells. Finally, we found that high level of MTDH expression correlated with poor prognosis of HGSOC. Therefore, lack of suppression of MTDH by miR-145 when p53 is dysfunctional leads to increased tumor growth and metastasis of HGSOC. Our study established a new link between p53, miR-145 and MTDH in the regulation of tumor growth and metastasis in HGSOC.     

结肠癌组织和癌旁组织miRNA表达谱研究

目的探讨结肠癌癌组织和癌旁组织中miRNA的表达差异,寻找潜在的结肠癌特异表达谱。方法miRNA表达芯片检测手术切除未发生转移的原位结肠癌组织和癌旁组织标本中miRNA表达水平,并采用Real-time PCR对差异表达的miRNA进行验证。结果miRNA表达芯片分析发现肿瘤细胞中24种miRNA表达下调,27种表达上调。miR-145、miR-143在癌组织中表达显著下调,miR-451在癌组织中表达显著上调,并被Real-time PCR方法进一步证实。结论结肠癌癌组织和癌旁组织中miRNA的表达存在差异,miR-145、miR-143在结肠癌组织中表达下调,miR-451表达上调,结肠癌组织具有特异miRNA表达谱,可作为结肠癌潜在诊断芯片进行开发。     

Exosomal microRNA: A Diagnostic Marker for Lung Cancer

BackgroundTo date, there is no screening test for lung cancer shown to affect overall mortality. MicroRNAs (miRNAs) are a class of small noncoding RNA genes found to be abnormally expressed in several types of cancer, suggesting a role in the pathogenesis of human cancer. Their accumulation within the peripheral circulation appears to be unique to cancer. The genome-wide expression profiling of miRNAs has been shown to be significantly different among primary lung cancers and corresponding noncancerous lung tissues. In studies demonstrating diagnostic miRNA signatures of NSCLC, specific miRNAs were overexpressed compared with normal lung tissue (miR-17-3p, miR-21, miR-106a, miR-146, miR-155, miR-191, miR-192, miR-203, miR-205, miR-210, miR-212, and miR-214). In this study, we evaluate the levels of circulating tumor exosomes, the circulating levels of exosomal small RNA, and specific exosomal miRNAs in patients with and without lung adenocarcinoma, correlating the levels with the American Joint Committee on Cancer (AJCC) stage of disease to validate it as an acceptable marker for diagnosis and prognosis in patients with adenocarcinoma of the lung.Patients and MethodsPlasma from patients with lung adenocarcinoma and a control group without known lung cancer or other active cancer were collected. Exosomes were isolated from plasma samples by a 2-step procedure using size-exclusion chromatography and magnetic activated cell sorting (MACS). Plasma samples (1 mL) were separated on Sepharose 2B, monitoring elution at 280 nm, and using a modified MACS procedure, exosomes of tumor origin were isolated using anti—epithelial cell adhesion molecule. Small RNA was isolated from circulating tumor exosomes using mirVana isolation kit (Ambion, Austin, TX) and this low molecular RNA enriched fraction was used for miRNA profiling as defined by microarray analysis. Low molecular weight RNA (5 μg) was used for hybridization on miRNA microarray chips. These miRNA were identified as hsa-miR-17-3p, hsa-miR-21, hsa-miR-106a, hsa-miR-146, hsa-miR-155, miR-191, miR-192, miR-203, miR-205, miR-210, miR212, and hsa-miR-214.ResultsTo date, 28 patients and 9 controls, AJCC stages I-IV, ages 21–80 years, were enrolled in the study. Exosome concentration ranged from 1.02–9.24 mg/mL for the lung adenocarcinoma group versus 0.62–1.7 mg/mL in the control group. The total miRNA concentration ranged from 131.1–275 ug/mL for the lung adenocarcinoma group versus 44.9–131.1 ug/mL in the control group. The mean exosome value in the lung cancer group was 2.85 mg/mL (CI, 1.94–3.76) and 0.77 mg/mL (CI, 0.68–0.86; P < .001). The mean RNA value in the lung cancer group was 158.6 ug/mL (CI, 145.7–171.5) and 68.1 ug/mL (CI, 57.2–78.9; P < .001). The only patient in the control group who had an exosome concentration > 1.0 mg/mL and RNA concentration > 100 ug/mL had a history of vulvar cancer without evidence of active disease. No correlation between the levels and the stage of disease was found. To compare the presence of specific miRNAs between tumors and their corresponding circulating exosomes, miRNA fractions were isolated and profiled from circulating tumor exosomes and the original tumor. MicroRNA profiling was performed in duplicate, using microarrays containing probes for 467 human mature miRNA. Comparisons between peripheral circulation-derived exosomes and tumors indicated that the miRNA signatures were not significantly different. This approach confirmed that the 12 specific miRNA were elevated in NSCLC and that the associations of these 12 were mirrored in the circulating exosomes. The levels of tumor-derived miRNA profiles exhibited a strong correlation with the levels of peripheral blood-derived exosomal miRNAs (for miR-17-3p, r = 0.76; miR-21, r = 0.77; miR-146, r = 0.88; miR-155, r = 0.85; miR-191, r = 0.83; miR-203, r = 0.85; miR-205, r = 0.91; and miR-214, r = 0.71).ConclusionThe significant difference in total exosome and miRNA levels between patients with lung cancer and controls suggests that exosomal miRNA is a screening test for lung adenocarcinoma. There is no obvious correlation between the total exosomal miRNA levels and stage of disease; however, it has been suggested in miRNA profiling studies of tumor tissue, that miRNA expression might be critical for the development of cancer but not for its progression. If specific miRNA levels predict response to treatment and can add prognostic information in addition to conventional staging needs further study. While validation studies will be necessary before bypassing the use with tumor mass biopsies, the use of exosomal miRNA profiling could extend this approach to screening of asymptomatic individuals as well as for monitoring disease recurrence.     

MicroRNA replacement therapy for miR-145 and miR-33a is efficacious in a model of colon carcinoma

MicroRNAs (miRNA) aberrantly expressed in tumors may offer novel therapeutic approaches to treatment. miR-145 is downregulated in various cancers including colon carcinoma in which in vitro studies have established proapoptotic and antiproliferative roles. miR-33a was connected recently to cancer through its capacity to downregulate the oncogenic kinase Pim-1. To date, miRNA replacement therapy has been hampered by the lack of robust nonviral delivery methods for in vivo administration. Here we report a method of miRNA delivery by using polyethylenimine (PEI)-mediated delivery of unmodified miRNAs, using miR-145 and miR-33a to preclinically validate the method in a mouse model of colon carcinoma. After systemic or local application of low molecular weight PEI/miRNA complexes, intact miRNA molecules were delivered into mouse xenograft tumors, where they caused profound antitumor effects. miR-145 delivery reduced tumor proliferation and increased apoptosis, with concomitant repression of c-Myc and ERK5 as novel regulatory target of miR-145. Similarly, systemic injection of PEI-complexed miR-33a was validated as a novel therapeutic targeting method for Pim-1, with antitumor effects comparable with PEI/siRNA-mediated direct in vivo knockdown of Pim-1 in the model. Our findings show that chemically unmodified miRNAs complexed with PEI can be used in an efficient and biocompatible strategy of miRNA replacement therapy, as illustrated by efficacious delivery of PEI/miR-145 and PEI/miR-33a complexes in colon carcinoma.     

miR-363-3p和miR-5100在非小细胞肺癌中的表达及其临床意义

目的:探讨小分子RNA(microRNA)miR-363-3p 和miR-5100在非小细胞肺癌中的表达及其临床意义.方法:利用荧光定量PCR的方法,检测肿瘤组织、癌旁组织及远离肿瘤的正常组织中致癌基因Myc的mRNA 和miR-363-3p、miR-5100的表达,然后分析miR-363-3p 和miR-5100与临床病理特征之间的相关性.结果:Myc在肿瘤组织中表达明显升高;miR-363-3p在肺癌组织中的表达明显低于正常组织(P<0.001),而在癌旁组织中的表达却远远高于正常组织(P<0.05);miR-5100在肺癌组织中的表达显著地高于正常组织(P<0.001),并且癌旁组织中的表达也高于正常组织(P<0.05).临床相关性分析显示,miR-363-3p的表达与淋巴结转移呈正相关(P<0.001),miR-5100的表达与临床分期也呈正相关性(P<0.05).结论:miR-363-3p 和miR-5100可能参与了非小细胞肺癌早期的发生和转移,并可能作为早期诊断和预后的分子标志物.     

An epigenetic auto-feedback loop regulates TGF-β type II receptor expression and function in NSCLC

The downregulation of transforming growth factor-β (TGF-β) type II receptor (TβRII) expression and function plays a pivotal role in the loss of the TGF-β-induced tumor suppressor function that contributes to lung cancer progression. The aberrant expression of miRNAs has been shown to be involved in the regulation of oncogenes and tumor suppressor genes. Our current study involving miRNA microarray, northern blot and QRT-PCR analysis shows an inverse correlation between miR-20a and TβRII expression in non-small cell lung cancer (NSCLC) tissues and cell lines. Stable expression of miR-20a downregulates TβRII in lung epithelial cells which results in an inhibition of TGF-β signaling and attenuation of TGF-β-induced cell growth suppression and apoptosis. Stable knock down of miR-20a increases TβRII expression and inhibits tumorigenicity of lung cancer cells in vivo. Oncogene c-Myc promotes miR-20a expression by activating its promoter leading to downregulation of TβRII expression and TGF-Δ signaling. MiR-145, which is upregulated by TGF-β, inhibits miR-20a expression by targeting c-Myc and upregulates TβRII expression. These correlations among miRNAs and cellular proteins are supported by TCGA public database using NSCLC specimens. These results suggest a novel mechanism for the loss of TβRII expression and TGF-β-induced tumor suppressor functions in lung cancer through a complex auto-feedback loop TGF-β/miR-145/c-Myc/miR-20a/TβRII.