反义miR-221/222上调p27kip1对MCF-7乳腺癌细胞系的放射增敏作用

目的探讨敲低miR-221／222表达上调p27^kip1对MCF-7人乳腺癌细胞系放射敏感性的影响。方法经生物信息学分析查询miR-221／222成熟体序列和它们与p27^kip1的关系。脂质体共转染反义寡聚核苷酸（反义miR-221／222）后,用Northern blot法检测转染后MCF-7细胞miR-221、miR-222表达水平;将实验细胞分为6组：对照组、对照照射组、无义序列组、无义序列照射组、反义miR-221／222共转染组和反义miR-221／222共转染照射组。用MTT法检测细胞增殖及放射协同作用,流式细胞仪分析细胞周期,克隆形成实验检测细胞增殖,Western blot分析p27^kip1蛋白的表达变化。数据间的方差分析采用F检验;两两比较采用LSD-t检验。结果经生物信息学分析显示miR-221／222成熟体序列的种子序列几乎一致,p27^kip1是miR-221／222的靶基因。Northern blot显示反义miR-221／222共转染组miR-221、miR-222的表达水平明显下降（miR-221：P=0．000;miR-222：P=0．000）。对照组及无义序列组之间miR-221、miR-222表达水平的差异无统计学意义（miR-221：P=0．371;miR-222：P=0．284）。MTT结果显示转染后第4天共转染组肿瘤细胞生长抑制效果最好,细胞增殖率明显低于对照组和无义序列组（P=0．000）,但与放射治疗无协同作用（P=0．091）。流式细胞术检测可见共转染组细胞周期存在G0／G1期阻滞（P=0．000）。经放射治疗后,可明显降低S期比例（P=0．002）。克隆形成实验表明反义miR-221／222可增加MCF-7细胞的放射敏感性。Western blot显示反义miR-221／222共转染组的p27^kip1蛋白表达明显上调（P=0．000）。结论反义miR-221／222通过上调p27^kip1蛋白表达可以增加MCF-7人乳腺癌细胞系放射敏感性。     

miR-153靶向ZEB2抑制胶质母细胞瘤侵袭与转移

目的:探究miR-153对人胶质母细胞瘤（glioblastoma,GBM）侵袭转移的影响及相关作用机制。方法:利用qRT-PCR检测miR-153在GBM中的表达;将miR-153转染至胶质瘤U251细胞后,应用qRT-PCR 验证转染效率;应用Western blot、Transwell及划痕实验检测U251细胞的上皮间质转化、细胞侵袭及转移能力的变化;应用qRT-PCR及Western blot检测ZEB2的mRNA和蛋白表达;利用质粒转染技术过表达miR-153后,同时过表达ZEB2,再应用Transwell及划痕实验检测U251细胞的侵袭及转移能力的变化。结果:与对照相比,miR-153在GBM中低表达;过表达miR-153显著抑制胶质瘤U251细胞的上皮间质转化、细胞侵袭及转移,并能够抑制U251细胞中ZEB2的蛋白表达;ZEB2过表达有效阻断了miR-153抑制U251细胞侵袭及转移的作用。结论:miR-153能够靶向下调ZEB2,进而抑制胶质瘤U251细胞上皮间质转化及细胞侵袭转移。     

下调miR-93表达抑制人脑胶质瘤细胞生长和侵袭的研究

目的 验证下调miR-93表达对人脑胶质瘤细胞株的生长和侵袭抑制作用.方法 合成miR-93抑制物,应用脂质体转染人脑胶质瘤细胞以抑制其表达,实时定量PCR检测转染后miR-93表达情况,流式细胞术检测、四甲基偶氮噻唑法(MTT)试验和软琼脂克隆形成实验评价细胞生长变化,tran-swell实验检测细胞侵袭能力的变化.结果 转染miR-93抑制物后,细胞中miR-93高表达被明显抑制,细胞周期进展迟滞,S期细胞减少,生长速度减慢,克隆形成能力减弱,穿过matrigel胶的细胞数减少,侵袭能力被抑制.结论 下调miR-93表达可抑制胶质瘤细胞的生长和侵袭.     

微小RNA-630对U251神经胶质瘤细胞增殖和凋亡的影响

目的 探讨微小RNA-630(miR-630)对U251神经胶质瘤细胞增殖和凋亡的影响及其调控机制。方法 荧光定量PCR(qPCR)检测人脑胶质瘤组织和细胞的miR-630表达水平。采用脂质体转染法向U251细胞转染miR-630模拟物mimics(miR-630 mimics组)及阴性对照序列(miR-NC mimics组),另选取未转染细胞为空白对照(Control)组，经qPCR验证miR-630 mimics显著增强miR-630基因表达后进一步进行功能研究：CCK-8和Hoechst染色法检测细胞增殖变化，采用流式细胞术、qPCR和Western blot分别检测凋亡细胞百分率和凋亡基因表达，qPCR和双荧光素酶报告基因系统分别检测20S蛋白酶体α1亚基(PSMA1)的表达及其与miR-630靶向关系验证。结果 miR-630在胶质瘤组织和细胞表达下调。与Control组和miR-NC mimics组相比，miR-630 mimics组U251细胞增殖能力下降，细胞凋亡增加，抗凋亡基因Bcl-2表达降低，cleaved caspase-3表达增加。过表达miR-630显著降低...     

miR-192在胶质瘤U251细胞中的表达及对其增殖、迁移及凋亡能力的影响

目的 探讨miR-192在胶质瘤U251细胞中的表达及对其增殖、迁移及凋亡等生物学能力的影响.方法 采用RT-PCR检测胶质瘤细胞株U251、LN18、U373和正常人脑胶质细胞株中HEB的表达水平.采用脂质体转染法将miR-192类似物(miR-192 mimics)和阴性对照(miR-negtive control...     

靶向Survivin基因的短发卡RNA在体内对U251细胞移植瘤的影响

Surivin基因属于凋死蛋白抑制因子（inhibitor of apoptosis,IAP）家族，具有抗细胞凋亡、促细胞增殖和促血管形成等多种生物学活性，其在脑胶质瘤发生和发展过程中的作用尚不完全明确，本研究结盟在观察稳定转染靶向Survivin基因的特异性短发卡RNA（shRNA）真核表达载体对人脑胶质母细胞瘤U251细胞裸鼠体内肿瘤生长和血管形成的影响。方法：将U251细胞，稳定转染Survivin基因shRNA真核表达载体pWHI-SR的U251-SR细胞，以及稳定转染空载体pWHI的U251-P细胞，分别接种于裸鼠背部皮下，建立人脑胶质瘤裸鼠皮下移植瘤模型，定期观察肿瘤生长情况，测定肿瘤体积、绘制肿瘤生长曲线，观察45天后处死动物、称瘤重，采用免疫组化SABC法检测Survivin、增殖细胞核抗原（proliferating cell muclear antigen，PCNA）以及八因子相关抗原（factor Ⅷ related antigen,FⅧRAg）在各组肿瘤标本中的表达，采用TUNEL法检测凋亡细胞，分别计算各组肿瘤标本的增殖指数（proliferative index,PI），凋亡指数（apoptotie index,AI）以及微血管密度（microvessel density,MVD）。结果：与U251、U251-SR组肿瘤标本，U251-SR组裸鼠肿瘤形成时间延迟，肿瘤生长缓慢，肿瘤体积及瘤重均明显减小（P〈0.01）；U251-P组裸鼠相丝，U251-SR组肿瘤标本Survivin蛋白表达明显下调：PI和MVD明显减少，AI明显升高（P〈0.001）。结论：靶向Survivin基因的sbRNA能够在体内明显抑制U251细胞的肿瘤生长和血管形成，Survivn基因可作为脑胶质瘤基因治疗的一个良好靶点，而RNA干涉（RNA interference,RNAi）技术可为脑胶瘤基因治疗的一个良好靶点，而RNA干涉（RNA interference，RNAi）技术可为脑胶质瘤的基因治疗提供新的重点手段。     

miR-126下调MMP-2抑制人脑胶质瘤细胞侵袭

目的初步探讨miR-126抑制人胶质瘤细胞侵袭的可能机制。方法化学合成miR-126,脂质体转染人脑胶质瘤U87细胞,应用RT-PCR、Western blot检测MMP-2基因和蛋白的表达情况,并应用Transwell小室检测转染前后细胞侵袭力的变化。结果miR-126上调后U87细胞的MMP-2基因和蛋白表达降低,并且细胞侵袭力明显降低。结论化学合成的miR-126在抑制人胶质瘤细胞侵袭过程中发挥重要作用,可能成为胶质瘤基因治疗的新靶点。     

NF-κB抑制剂QNZ对人胶质瘤细胞生物学功能的影响

目的:探究NF-κB抑制剂QNZ对人胶质瘤细胞系U251生物学功能的影响。方法:胶质瘤U251细胞中加入QNZ处理,用CCK8法、Transwell实验、流式细胞术和Western blot检测细胞增殖、侵袭、凋亡以及Caspase-3的表达。结果:QNZ处理后绘制出生长曲线,发现胶质瘤细胞增殖受到抑制。QNZ降低U251细胞的侵袭性。不同浓度QNZ处理后,U251细胞凋亡增加,与QNZ浓度有相关性。QNZ处理后细胞周期被阻滞于G2期。结论:QNZ抑制胶质瘤细胞U251的增殖和细胞侵袭力,促进凋亡并阻滞细胞周期进展,为胶质瘤治疗提供新的思路。     

p53基因对胶质瘤细胞系U251生长抑制作用的研究

背景与目的：肿瘤抑制基因p53是调节多种与细胞周期、凋亡、DNA修复等有关基因表达的转录因子。p53基因在大约30％的胶质瘤中发生突变，在胶质瘤的发生和发展中起重要作用。本文主要探讨野生型p53基因过表达对脑胶质瘤细胞系U251细胞生长抑制的机制。方法：通过p53腺病毒表达载体pAdCMV-p53及空载体pAdCMV-lacZ分别感染U251细胞系，RT-PCR及Westem blot方法检测转染效率；并通过MTT检测生长抑制率、流式细胞仪检测细胞周期及TUNEL检测分析细胞凋亡等指标观察p53基因对U251细胞生长的影响。结果：MOI为100时，野生型p53基因的过表达可引起U251细胞G0、G1期阻滞、诱导U251细胞凋亡以及引起U251细胞生长抑制。结论：p53基因可以通过细胞周期G0、G1期阻滞及诱导细胞凋亡抑制胶质瘤细胞系U251的生长。     

miR-221/222 is the regulator of Cx43 expression in human glioblastoma cells

The miR-221/222 cluster is significantly upregulated in malignant glioma cells and regulates the expression of multiple genes associated with glioma cell proliferation, invasion and apoptosis, which was shown in our previous studies. Cx43 has been identified as a tumor suppressor and major component for the establishment of gap junction intercellular communication (GJIC) in glial cells, which is frequently reduced or deleted in high-grade gliomas. According to bioinformatic analysis, connexin 43 (Cx43) may be one of the target genes of miR-221/222. The aim of the present study was to validate Cx43 as a target gene of miR-221/222 and to determine whether overexpression of miR-221/222 is one of the molecular mechanisms for the reduced expression of Cx43 in malignant gliomas. We transfected miR-221/222 antisense oligonucleotides (AS-miR-221/222) into U251 human glioblastoma cells using a lipofectamine method. Northern blot analysis was conducted to detect the expression of the miR-221/222 cluster. Luciferase reporter assays were exploited to confirm Cx43 as a target gene of miR-221/222. Cx43 expression was assessed by western blotting and immunofluorescence staining. Scrape loading and dye transfer (SLDT) assays were used for examination of GJIC. Proliferation and invasion of U251 cells were evaluated by MTT and transwell assays, respectively. Cell cycle kinetics and apoptosis were determined with flow cytometry. We found that expression of the miR-221/222 cluster was significantly reduced while Cx43 expression was upregulated in U251 cells transfected with AS-miR-221/222, and the GJIC deficiency in parental U251 cells was re-established. Moreover, the luciferase activity determined by the luciferase reporter assay was enhanced in AS-miR-221/222-treated cells, and cell proliferation and invasion were suppressed while apoptosis was induced. We conclude that miR-221/222 function as oncogenic microRNAs in human gliomas, at least in part, by targeting Cx43.     

Downregulation of miR-221/222 sensitizes glioma cells to temozolomide by regulating apoptosis independently of p53 status

A previous study showed that miR-221/222 can regulate cell apoptosis. p53 is a well known tumor suppressor which can influence the chemosensitivity of glioma cells. However, the effect of miR-221/222 in gliomas with different p53 status is unknown. Here, we demostrate that knockdown of miR-221/222 increases apoptosis in human gliomas of different p53 types (U251 cells, p53 mutant-type; LN308 cells, p53 null-type; and U87 cells, p53 wild-type). Furthermore, the effect of miR-221/22 caused no change of p53 expression in the glioma cells studied. In addition, when a specific siRNA against p53 was employed in U87 cells, no attenuation of apoptosis was found after knockdown of miR-221/222. Importantly, we found that As-miR-221/222-treated cells increased expression of Bax, cytochrome c, Apaf-1 and cleaved-caspase-3. Our results showed that low expression of miR-221/222 sensitized glioma cells to temozolomide (TMZ); in addition, ectopic expression of PUMA by pcDNA-PUMA had a similar effect. Taken together, our study indicates that downregulated miR-221/222 can sensitize glioma cells to TMZ by regulating apoptosis independently of p53 status.     

Overexpression of septin 7 suppresses glioma cell growth

Our previous study demonstrated that SEPT7 was downregulated at mRNA level in human gliomas. This study is to further examine the expression of SEPT7 in glioma samples and characterizes its role on cell cycle progression and growth of glioma cells. mRNA and protein expression of SEPT7 were detected by RT-PCR, immunohistochemical staining, and western blot analysis in human glioma specimens and normal brain tissues. A pcDNA3-SEPT7 expression plasmid was constructed and transfected into human glioblastoma cell line U251, and cell proliferation and apoptosis were examined. The growth of established U251 and TJ905 subcutaneous xenograft gliomas was measured in nude mice treated with pcDNA3-SEPT7 and U251 xenograft tumors treated with SEPT7 siRNA. SEPT7 expression is negatively correlated with the increase of glioma grade. Overexpression of SEPT7 is able to inhibit cell proliferation and arrest cell cycle progression in the G0/G1 phase both in vitro and in vivo. Knocking down further the already low endogenous expression of SEPT7 in U251 xenograft tumors with siRNA leads to faster tumor growth compared with control tumors. This study demonstrates that SEPT7 is involved in gliomagenesis and suppresses glioma cell growth.     

MicroRNA-27a对U251胶质瘤细胞的影响

目的 探讨microRNA-27a(miR-27a)对U251胶质瘤细胞的影响。方法 采用体外瞬时转染的方法过表达或抑制U251细胞中的miR-27a,MTT方法检测细胞的增殖情况,Transwell侵袭试验测定U251胶质瘤细胞的侵袭能力,Real-time PCR方法测定U251细胞中miR-27a和PPARγ的含量。结果 抑制miR-27a可降低U251胶质瘤细胞增殖能力,减弱U251胶质瘤细胞侵袭能力,增加PPARγ的含量;过表达miR-27a促进U251胶质瘤细胞增殖能力,提高U251胶质瘤细胞侵袭能力,减少PPARγ的含量。结论 抑制miR-27a有利于降低U251胶质瘤细胞的增殖能力和侵袭能力。     

替莫唑胺通过调控miR-216a/PRKCA抑制胶质瘤细胞U251增殖和侵袭作用的研究

目的:探讨替莫唑胺抑制胶质瘤细胞U251增殖和侵袭的作用,推测其作用机制是通过微小RNA-216a（microRNA-216a,miR-216a）/蛋白激酶Cα(protein kinase C-alpha,PRKCA)进行调控。方法:体外培养胶质瘤细胞U251,用不同剂量替莫唑胺染毒48 h后,构建野生型PRKCA 3' UTR-荧光素酶报告载体及检测荧光素酶活性,检测替莫唑胺对胶质瘤细胞U251增殖和侵袭的影响及miR-216a和PRKCA表达的影响。结果:miR-216a mimics使野生型PRKCA 3' UTR-荧光素酶报告载体的活性下降了47.52%,差异具有统计学意义（P＜0.05）;miR-216a mimics使突变型PRKCA 3' UTR-荧光素酶报告载体的活性下降不显著,差异无统计学意义（P＞0.05）。与空白对照组比较,低、中、高剂量组胶质瘤细胞U251增殖率、侵袭细胞数、PRKCA mRNA相对表达量和PRKCA蛋白表达量均降低,miR-216a mRNA相对表达量均增高,差异具有统计学意义（P＜0.05）;随着替莫唑胺剂量的增加,胶质瘤细胞U251增殖率、侵袭细胞数、PRKCA mRNA相对表达量和PRKCA蛋白表达量随之降低,miR-216a mRNA相对表达量随之增高,差异具有统计学意义（P＜0.05）。结论:替莫唑胺可以通过促进miR-216a的表达而抑制PRKCA的表达,降低胶质瘤细胞U251增殖和侵袭。     

miR-221/222 overexpession in human glioblastoma increases invasiveness by targeting the protein phosphate PTPμ

Glioblastoma is the most frequent brain tumor in adults and is the most lethal form of human cancer. Despite the improvements in treatments, survival of patients remains poor. In order to identify microRNAs (miRs) involved in glioma tumorigenesis, we evaluated, by a miRarray, differential expression of miRs in the tumorigenic glioma LN-18, LN-229 and U87MG cells compared with the non-tumorigenic T98G cells. Among different miRs we focused our attention on miR-221 and -222. We demonstrated the presence of a binding site for these two miRs in the 3' untranslated region of the protein tyrosine phosphatase μ (PTPμ). Previous studies indicated that PTPμ suppresses cell migration and is downregulated in glioblastoma. Significantly, we found that miR-221 and -222 overexpression induced a downregulation of PTPμ as analyzed by both western blot and real-time PCR. Furthermore, miR-222 and -221 induced an increase in cell migration and growth in soft agar in glioma cells. Interestingly, the re-expression of PTPμ gene was able to revert the miR-222 and -221 effects on cell migration. Furthermore, we found an inverse correlation between miR-221 and -222 and PTPμ in human glioma cancer samples. In conclusion, our results suggest that miR-221 and -222 regulate glioma tumorigenesis at least in part through the control of PTPμ protein expression.     

miR-223负调控SOX9对胶质瘤生物学行为的影响

目的:探讨miRNA通过靶向调控促癌基因SOX9的表达影响胶质瘤生物学行为的作用及机制。方法:采用qRT-PCR检测miR-223在WHO分级低级别(Ⅰ和Ⅱ)与高级别(Ⅲ和Ⅳ)脑胶质瘤组织和癌旁正常组织中的表达水平,miR-223在正常人星形胶质细胞、A172、U251、U87和U373胶质瘤细胞中的表达水平。采用生物信息软件预测SOX9是miR-223的潜在靶基因,并通过双荧光素酶报告基因实验进行验证。采用qRT-PCR、Western blot检测SOX9在各WHO分级脑胶质瘤组织和各脑胶质瘤细胞株中的表达。多种体外实验检测miR-223和SOX9对脑胶质瘤细胞增殖,侵袭、迁移及周期的影响。构建脑胶质瘤裸鼠移植瘤模型,检测miR-223对体内移植瘤生长的影响。结果:miR-223在脑胶质瘤组织及脑胶质瘤细胞中均呈现低表达,并且通过抑制靶基因SOX9的靶向调控作用抑制脑胶质瘤细胞恶性生物学行为。同时脑胶质瘤裸鼠移植瘤模型中,miR-223过表达可下调SOX9的表达水平并抑制裸鼠体内移植瘤的生长。结论:miR-223通过抑制靶基因SOX9的表达水平在胶质瘤中扮演抑癌基因的角色,提示其具有成为胶质瘤诊疗新靶点的潜力。     

SDF-1 and CXCR4 are up-regulated by VEGF and contribute to glioma cell invasion

Glioma cells produce vascular endothelial growth factor (VEGF) to induce vascularization and thereby supply the malignant tissue with oxygen and nutrients. However, little is known about the direct effects of VEGF on tumor cells. In this study, we investigate the ability of VEGF to promote proliferation and invasion of human glioma cells (U251n). Since the chemokine and its receptor, SDF-1/CXCR4, promote glioma cell proliferation and are up-regulated in human glioblastomas, we also tested the effects of VEGF on SDF-1 and CXCR4 mRNA expression. Using cell culture, the effect of VEGF on proliferation of U251n cells was measured using ELISA to detect incorporated BrdU as a marker of DNA syntheses. The effects of VEGF and SDF-1 on U251n cell invasion and proliferation were measured using inhibitors to VEGF receptor1 and receptor2, DC101 and MF1, respectively, and a CXCR4 antagonist (AMD3100). SDF-1 and CXCR4 mRNA expression in U251n and U87MG cells were measured using quantitative PCR. VEGF antisense phosphorothioate oligodeoxynucleotide (AS-VEGF) was also used to down-regulate VEGF expression in U251n cells. VEGF significantly increased U251n cell proliferation and invasion in a dose-dependent manner. These effects were blocked by the VEGF receptor inhibitors, DC101/MF1. The CXCR4 antagonist AMD3100 blocked U251n increased invasion, but not proliferation. CXCR4 and SDF-1 mRNA were up-regulated when U251n and U87MG cells were treated with VEGF. Eight micrometer VEGF antisense phosphorothioate oligodeoxynucleotide (AS-VEGF) down-regulated CXCR4 and SDF-1 mRNA levels in U251n cells. VEGF has a direct effect on U251n glioma cell proliferation and invasion. VEGF up-regulates SDF-1 and CXCR4 mRNA expression, and contributes to U251n cell invasion.