胶质瘤细胞系T98G、U87和U251中CYP17A1的表达及意义

目的探讨细胞色素P450c17a酶(CYP17A1)在人神经胶质瘤细胞系T98G、U87和U251中的表达情况。方法采用Western blot和实时荧光定量PCR于蛋白质水平和mRNA水平检测细胞色素P450c17a酶(CYP17A1)在三种人胶质瘤细胞系中的表达。结果 Western blot检测出CYP17A1蛋白在胶质瘤细胞系T98G、U251和U87中的相对表达量为0.518±0.052、0.460±0.034和0.142±0.025。T98G和U251的CYP17A1蛋白表达水平明显高于U87,差异有统计学意义(P0.05)。实时荧光定量PCR检测结果显示CYP17A1的mRNA在T98G、U251和U87中相对转录水平为1.000±0.122、0.960±0.079、0.611±0.045,T98G和U251细胞中CYP17A1的mRNA转录水平均高于U87,差异有统计学意义(P0.05)。同时Western blot和实时荧光定量PCR都指出T98G和U251在CYP17A1在蛋白和mRNA的表达上无统计学差异(P0.05)。结论人胶质瘤细胞系T98G和U251中CYP17A1的表达量较高,这两种细胞系可作为良好的细胞模型用来研究CYP17A1在胶质瘤中的作用机制以及以CYP17A1为靶点的肿瘤治疗等。     

Wip1基因在人脑胶质瘤细胞恶性增殖中的作用及其机制

目的研究Wip1基因在人脑胶质瘤细胞增殖的作用及机制。方法构建人Wip1基因RNA干扰(RNAi)慢病毒载体,有效沉默胶质瘤细胞U251及U87-MG细胞的Wip1基因表达,检测细胞增殖能力。流式细胞术PI单染法检测Wip1基因沉默后细胞周期分布。实时定量PCR法及Western blotting分别检测差异性基因m RNA及蛋白表达。结果胶质瘤细胞Wip1基因表达被有效沉默。Wip1基因沉默的胶质瘤细胞增殖变慢,在U87-MG细胞更加明显。细胞周期分析显示:Wip1基因沉默对U251细胞周期无明显影响,而U87-MG细胞则在10 d时出现明显S期增多和G1、G2期细胞减少。Wip1基因沉默后,U251细胞中CDKN2A和p14ARF基因表达下调,而在U87-MG细胞中表达均上调。Western blotting结果显示:在U251与U87-MG胶质瘤细胞中p38MAPK表达均上调。在U87-MG细胞中p53及p-p53(Ser 15)表达均上调,但在U251细胞中无明显变化。结论 Wip1对胶质瘤细胞增殖具有重要作用。在U87-MG细胞增殖作用主要与其调节p53功能有关。     

长链非编码RNA SNORD3A在脑胶质瘤中的表达变化及功能研究

目的探讨长链非编码(lncRNA)SNORD3A在胶质瘤组织和胶质瘤细胞系中的表达变化,以及对胶质瘤细胞增殖和侵袭能力的影响。方法采用生物信息学方法分析美国国家生物技术信息中心(NCBI)GEO数据库收录的GSE58276中差异表达的lncRNA,采集2017年6月至2019年8月手术切除的胶质瘤组织标本30例,实时荧光定量聚合酶链反应(PCR)检测lncRNA SNORD3A表达水平;小干扰RNA转染胶质瘤细胞系T98G和U251,CCK-8细胞增殖实验检测胶质瘤细胞增殖能力、Transwell细胞侵袭实验检测胶质瘤细胞侵袭能力、Western blotting法检测胶质瘤细胞c-Myc mRNA和蛋白表达变化。结果与对照组相比,胶质瘤组织lncRNA SNORD3A表达水平升高(P=0.000);与HEB细胞相比,胶质瘤细胞系T98G、U87、U251和U373 lncRNA SNORD3A表达升高(均P 0.05)。si-SNORD3A-1组和si-SNORD3A-2组T98G细胞(P=0.001,0.007)和U251细胞(P=0.002,0.009)lncRNA SNORD3A表达水平低于对照组;转染后24、48和72 h,si-SNORD3A-1组和si-SNORD3A-2组T98G细胞(均P=0.000)和U251细胞(均P=0.000)增殖能力低于对照组;转染后48 h,si-SNORD3A-1组和si-SNORD3A-2组穿过小室的T98G和U251细胞数目少于对照组(均P=0.000)、c-Myc mRNA和蛋白表达水平低于对照组(均P 0.01)。结论 lncRNA SNORD3A可能通过靶向c-Myc蛋白促进T98G和U251细胞的增殖和侵袭。     

TIMP-2基因对人脑胶质瘤U87细胞周期与增殖的影响

目的探讨金属蛋白酶组织抑制因子(TIMP-2)对人脑胶质瘤细胞的抑制作用,主要是对细胞周期与细胞增殖的作用.方法用含TIMP-2基因的重组腺病毒载体,体外转染人胶质瘤细胞系U87,用Western blot检测目的蛋白的表达.通过细胞生长实验,流式细胞仪分析技术检测U87转染前后细胞增殖、周期与凋亡的变化.结果转染AdTIMP-2病毒后的U87细胞TIMP-2蛋白表达上调,转染后对U87细胞的生长有抑制作用,并出现明显的G0 -G1 期阻滞,但无明显的细胞凋亡峰出现.结论重组腺病毒载体介导的TIMP-2基因在体外对人脑胶质瘤细胞系U87 的生长有抑制作用,可作为胶质瘤治疗的有效工具.     

槐定碱抑制人胶质瘤U87MG细胞株增殖及其作用机制研究

目的探讨槐定碱抑制人胶质瘤U87恶性胶质瘤(U87MG)细胞株增殖作用及其相关机制。方法将各个浓度的槐定碱加入到人胶质瘤U87MG细胞株中,应用四唑氮盐比色法测定槐定碱对肿瘤细胞生长的抑制作用,流式细胞仪测定槐定碱对U87MG细胞凋亡和细胞周期的变化,生化检验测定肿瘤细胞内活性氧簇(ROS)和谷胱甘肽(GSH)含量,实时荧光定量聚合酶链式反应和蛋白免疫印迹法分别检测肿瘤相关基因mRNA表达和蛋白表达的变化,荧光素酶报告基因法检测肿瘤细胞中泛素-蛋白酶体、叉头盒蛋白M1(FoxM1)、核转录因子kappa B(NF-kb)、激活子蛋白-1(AP-1)的活性的变化。结果槐定碱能够显著抑制细胞增殖,阻滞细胞周期在G2/M期;诱导细胞凋亡,引起ROS产生和GSH含量减少;促使p27、周期蛋白依赖性激酶2、Survivin、Livin、B淋巴细胞瘤-2、E2启动子结合细胞因子1等基因表达下调,同时上调半胱氨酸天冬氨酸蛋白酶-3/8、p53、线粒体来源的第2个半胱氨酸蛋白酶激活剂、c-Jun氨基末端激酶和p38-丝裂原活化蛋白激酶等基因的表达;显著抑制泛素-蛋白酶体活性和FoxM1、NF-kb、AP-1的转录活性。结论槐定碱可能通过诱导细胞凋亡和ROS积聚,激活线粒体信号通路来发挥抗肿瘤活性。槐定碱能够作为一种新的药物来治疗胶质瘤。     

HER-2/neu siRNA对人胶质瘤细胞增殖及相关基因表达的影响

目的 探讨HER-2/neu特异性小干扰核糖核酸(siRNA)对高表达HER-2/neu的人胶质瘤细胞系U251MG和T98G增殖的影响及其可能机制.方法 脂质体介导HER-2/neu siRNA转染体外常规培养的U251MG和T98G细胞,同时设脂质体为对照组.转染后3 d实时定量PCR和免疫印迹实验检测HER-2/neu mRNA和蛋白的表达;四甲基偶氮唑盐(MTT)比色法检测转染后3、4d细胞增殖率的变化;免疫印迹实验检测转染后3 d细胞蛋白激酶B(AKT)、磷酸化AKT、磷酸化叉头转录因子(FOXO1)、p27、Cyclin D1蛋白的表达.结果 与脂质体组比较,HER-2/neu siRNA组U251MG、T98G细胞转染后3 d HER-2/neu mRNA和蛋白的表达均下降,转染后3、4 d细胞增殖率均下降,转染后3 d细胞磷酸化AKT和磷酸化FOXO1水平降低、p27蛋白表达增多、Cyclin D1蛋白表达减少,差异均有统计学意义(P＜0.05).结论 HER-2/neu siRNA转染人胶质瘤细胞系U251MG和T98G后明显抑制细胞增殖,可能与抑制AKT/FOXO1信号通路,调控下游基因p27、Cyclin D1蛋白的表达有关.

Abstract：

Objective To investigate the effect of HER-2/neu siRNA on proliferation of human glioma cell lines U251MG and T98G which over-express HER-2/neu, and explore its mechanism.Methods Liposome-mediated HER-2/neu siRNA was transfected into human glioma cell lines U251MG and T98G;lipofectin group was established as controls. The mRNA and protein levels of HER-2/neu were detected by real-time PCR and Western blotting 3 d after the transfection. The proliferation of glioma cells was investigated using methyl thiazolyl tetrazolium (MTT) assay 3 and 4 d after the transfection. The effects of HER-2/neu siRNA on AKT/FOXO1 pathway and protein expression of p27 and Cyclin D1 were studied using Western blotting. Results HER-2/neu mRNA and protein expressions in the transfected U251MG cells were decreased to (28.833±4.174)% and (22.167±1.955)% while those in cells of the lipofectin group were (92.067±5.698)% and (96.100±1.682)%, respectively,with significant differences (P=0.000, 0.001). HER-2/neu mRNA and protein expressions of the transfected T98G cells were decreased to (28.067 ±6.165)% and (12.433 ±8.864)% while those in the untransfected cells were (96.000 ±5.110)% and (94.333 ±3.215)%, respectively, with significant differences (P=0.001, 0.008). Three d after the transfection, the rates of proliferation in the transfected T98G and U251MG cells were (58.467±5.561)% and (63.933±5.363)%, respectively;4 d after the transfection, the rates of proliferation in the transfected T98G and U251MG cells were (57.500±4.770)% and (60.167±3.253)%, respectively;an obvious decrease was noted as compared them with cells of the lipofectin group (P=0.020, 0.023, 0.021, 0.008). Cyclin Dl expression was decreased, while p27 protein expression was up-regulated in the transfected cells as compared with those in cells of the lipofectin group (P<0.05). Moreover, the levels of phosphorylated AKT and phosphorylated FOXO1 were decreased in the transfected cells as compared with those in cells of the lipofectin group (P<0.05).Conclusion The specific siRNA targeting HER-2/neu in human glioma cell lines U251MG and T98G could inhibit the cell proliferation, which might relate to the suppression of AKT/FOXO1 pathway and the regulation of expresion of thier downstream molecules such as p27 and Cyclin D1.     

p53基因、PTEN基因协同对胶质瘤U251细胞系生长抑制作用的研究

目的探讨p53基因和PTEN基因在脑胶质瘤细胞系U251发生发展过程中的作用机制。方法用不同MOI的p53腺病毒表达载体pAdCMV-p53及空载体pAdCMV-lacZ分别感染表达野生型PTEN基因和突变型PTEN基因的细胞系,RT-PCR及Westernblot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基因及PTEN基因对U251细胞生长的影响。结果MOI为100时,p53基因可引起U251细胞G0G1期阻滞、诱导细胞凋亡,生长抑制;MOI为50时,U251-p53 PTEN生长抑制率明显高于U251-p53,并能出现细胞凋亡,而U251-p53仅出现少量细胞凋亡。结论p53基因可以通过细胞周期G0G1期阻滞及诱导细胞凋亡抑制胶质瘤细胞系U251的生长;PTEN基因可以促进p53基因对胶质瘤细胞系U251的生长抑制作用,并能增加U251细胞对p53基因诱导凋亡的敏感性。     

GOLPH3对人脑胶质瘤细胞周期及凋亡调节作用的研究

目的探讨GOLPH3(Golgi phosphoprotein 3)对人脑胶质瘤细胞周期及凋亡的影响及调控机制。方法在U251胶质瘤细胞中利用siRNA下调GOLPH3的表达后,流式细胞术检测细胞周期和凋亡的变化,RT-PCR和Western blot技术检测细胞周期相关蛋白cyclin D1,p21~(waf1/cip)(p21)和p53在核酸和蛋白水平的变化,同时检测下调GOLPH3对Akt、p Akt蛋白水平的影响。结果 3条GOLPH3 siRNA均能下调GOLPH3的蛋白表达(均P0.05);下调GOLPH3使细胞周期阻滞在G0/G1期(P0.05),细胞凋亡率明显增加(P0.05)。同时发现下调GOLPH3使cyclin D1的核酸和蛋白水平降低,p21的核酸和蛋白水平升高而p53的核酸和蛋白水平无明显变化。下调GOLPH3的表达降低p Akt的蛋白水平(P0.05),但对Akt无影响。结论在U251细胞中下调GOLPH3使细胞阻滞在G0/G1期,促进细胞凋亡。下调GOLPH3对细胞周期的调节作用可能是通过抑制PI3K-Akt信号通路,进而下调cyclin D1和上调p21的表达来实现的。     

LRIG3基因对脑胶质瘤细胞系U87和U251的细胞周期、侵袭性和凋亡的影响

目的探讨过表达的富含亮氨酸重复序列免疫球蛋白样蛋白3(LRIG3)基因对脑胶质瘤细胞系U251和U87的细胞周期、侵袭能力和凋亡的影响。方法将过表达的LRIG3质粒(实验组)和空白质粒(对照组)经慢病毒法感染胶质瘤细胞系U251和U87,筛选稳定细胞株,通过逆转录聚合酶链反应(RT-PCR)和Westernblot检测LRIG3表达的变化,碘化丙啶染色后用流式细胞仪测定细胞周期的变化,TransWell小室法检测细胞的侵袭能力,用免疫组化原位末端标记法(TUNEL)检测各组凋亡细胞。结果与对照组相比,实验组U251与U87细胞中LRIG3mRNA水平分别上升67.6%和79.9%,蛋白表达水平分别升高62.3%和91.0%,差异有统计学意义(P<0.05)。实验组U251细胞中S期与G2/M期细胞数之和低于对照组,有统计学意义(P<0.05);但U87细胞与对照组比无明显差异。实验组U251细胞中穿出细胞数量均明显少于对照组(P<0.05),TUNEL染色结果显示对照组U251细胞凋亡率为23.4%,实验组为35.7%;对照组U87细胞凋亡率为20.2%,实验组为39.5%;对照组与实验组间凋亡率均有明显差异(P<0.05)。结论 LRIG3基因过表达能阻断细胞周期于S期和G2/M期,降低胶质瘤细胞的侵袭能力,加速细胞凋亡。     

丙戊酸诱导胶质瘤细胞自噬及其机制研究

目的对丙戊酸诱导胶质瘤细胞发生自噬性死亡的过程进行观察,并初步探讨其可能的机制。方法丙戊酸处理人脑胶质瘤细胞系U87、T98G和SF295,台盼蓝染色检测细胞活性并计算细胞存活率;流式细胞仪测定细胞周期,透射电子显微镜和荧光测定仪观察细胞超微结构及自噬水平,West-ern blotting检测经丙戊酸处理后细胞内LC3-Ⅱ、Beclin-1、p-Akt和p-p70S6K等蛋白质的表达水平。结果经不同浓度丙戊酸处理后,人脑胶质瘤细胞系U87、T98G和SF295细胞活性明显受到抑制,其胶质瘤细胞半数抑制浓度分别为(2.45±0.32)、(4.78±0.62)和(6.62±0.95)mmol/L,其中丙戊酸对人脑胶质瘤细胞系U87具有较明显的杀伤作用(P<0.05)。透射电子显微镜观察可见人脑胶质瘤细胞系U87细胞胞质内有大量自噬体和自噬溶酶体,其自噬水平随丙戊酸浓度的升高而逐渐增强。经丙戊酸处理后,人脑胶质瘤细胞系U87细胞自噬相关蛋白LC3-Ⅱ和Beclin-1表达水平明显升高,而p-Akt和p-p70S6K表达水平明显降低。结论丙戊酸可诱导胶质瘤细胞发生自噬,其诱导胶质瘤细胞发生自噬的机制可能与阻断Akt信号转导通路有关。     

miR-153下调FOXR2、CDK8和CDK13的表达抑制胶质母细胞瘤细胞增殖

目的 探讨miR-153对胶质母细胞瘤细胞增殖的影响。方法 体外培养胶质母细胞瘤细胞系U87、U251、SHG-44和T98G细胞,分别转染miR-153质粒（miR-153组）、空载质粒（载体组）和miR-153突变质粒（miR-153突变组）,另设置空白对照组（不转染任何质粒）。RT-PCR检测miR-153、FOXR2、CDK8和CDK13的表达,MTT法检测细胞增殖能力。结果 miR-153组U87、U251、SHG-44和T98G细胞miR-153表达水平较载体组和空白对照组显著上升（P<0.05）,细胞增殖水平较载体组和空白对照组均显著降低（P<0.05）。miR-153组U87、U251、SHG-44和T98G细胞FXOR2、CDK8和CDK13的mRNA水平较miR-153突变组、载体组和空白对照组均显著下降（P<0.05）,而后三组之间均无统计学差异（P>0.05）。结论 miR-153抑制胶质母细胞瘤细胞增殖,其机制可能与抑制FXOR2、CDK8和CDK13表达有关。     

Microtubule-severing ATPase spastin in glioblastoma: increased expression in human glioblastoma cell lines and inverse roles in cell motility and proliferation

We studied the expression and distribution of the microtubule-severing enzyme spastin in 3 human glioblastoma cell lines (U87MG, U138MG, and T98G) and in clinical tissue samples representative of all grades of diffuse astrocytic gliomas (n = 45). In adult human brains, spastin was distributed predominantly in neuronsand neuropil puncta and, to a lesser extent, in glia. Compared with normal mature brain tissues, spastin expression and cellular distribution were increased in neoplastic glial phenotypes, especiallyin glioblastoma (p < 0.05 vs low-grade diffuse astrocytomas). Overlapping punctate and diffuse patterns of localization wereidentified in tumor cells in tissues and in interphase and mitotic cells ofglioblastoma cell lines. There was enrichment of spastin in the leading edges of cells in T98G glioblastoma cell cultures and in neoplastic cell populations in tumor specimens. Real-time polymerase chain reaction and immunoblotting experiments revealed greater levels of spastin messenger RNA and protein expression in theglioblastoma cell lines versus normal human astrocytes. Functional experiments indicated that spastin depletion resulted in reduced cell motility and higher cell proliferation of T98G cells. Toour knowledge, this is the first report of spastin involvement incellmotility. Collectively, our results indicate that spastinexpression in glioblastomas might be linked to tumor cell motility, migration, and invasion.     

Caveolin-1 expression is maintained in rat and human astroglioma cell lines

Caveolin-1 is the principal structural and functional component of caveolae, a plasmalemmal compartment that has been proposed to sequester lipid and protein components that participate in transmembrane signal transduction processes. Multiple studies reveal a reduction in the expression level of caveolin-1 mRNA and protein in many carcinomas as well as transformed cells. The human caveolin-1 gene is localized to a suspected tumor suppressor locus (7q31.1). Collectively, these data have been taken to imply that caveolin-1 may function in a tumor suppressor capacity. To determine if a reduction in the expression level of caveolin-1 mRNA and protein accompanied the transformation of astrocytes, we undertook studies of two transformed rat astroglial cell lines, C6 and DI TNC(1), as well as several cell lines derived from human glioblastoma tumors: T98G, U87MG, U118MG, U138MG, and U373MG. Ultrastructural, immunolocalization, immunoblot, and Northern blot analyses demonstrated that caveolin-1 message and protein were expressed in all rat and human glioma cells. The localization pattern, buoyant density, and detergent-insolubility property of caveolin-1 protein were indistinguishable from that determined for nontransformed type 1 astrocytes in culture. Nucleotide sequence analyses of caveolin-1 cDNAs indicate that mutations are not present in the caveolin-1 sequence in any of the glioma cell types. Taken together with previous analyses, these data indicate that, at least for astrocytes, the process of transformation in and of itself is not solely sufficient to reduce the level of caveolin-1 expression, and that caveolin-1 expression in and of itself is not solely sufficient to prevent the acquisition of a transformed phenotype.     

Notch1通路与胶质瘤细胞管道形成能力相关性研究

目的探索胶质瘤细胞来源的管道(glioma clls derived vessels,GCDV)的形成机制。方法将胶质瘤细胞株U87、U251、U373、SF295、T98G、SKMG-4和C6进行体外三维培养,观察其管道形成能力。Western blot检测各个胶质瘤细胞株Notch1、Dll4蛋白的表达情况。结果三维培养C6细胞单个视野下(100×)的平均管道数(25.2±5.0)个,U373为(36.4±3.20)个,U87为(19.0±2.2)个,T98G为(12.6±2.4)个,SF295为(4.0±2.)个,U251为(0.2±0.4)个,SKMG-4为0。Notch1在U87、U251、T98G、SF295、SKMG-4、C6、U373表达相关密度分别为0.34、0.21、0.79、0.04、0.28、1.75、1.19,与管道形成能力显著相关(r=0.778,P=0.019);Dll4表达相关密度与管道形成能力不相关(r=0.635,P=0.062)。结论 Notch1蛋白表达与细胞株管道形成能力密切相关,而Dll4蛋白的表达与细胞株管道形成能力有待进一步探索。     

Histone deacetylase inhibitor, FK228, induces apoptosis and suppresses cell proliferation of human glioblastoma cells in vitro and in vivo

We investigated the effects of FK228 on cell proliferation and apoptosis against human glioblastoma (GM) T98G, U251MG, and U87MG cells. Upon exposure to FK228, cell proliferation was inhibited, and apoptosis detected by the cleavage of CPP32 was induced. FK228 increased the expression levels of p21 (WAF-1) and of pro-apoptotic Bad protein in all GM cells. Furthermore, FK228 treatment also reduced the anti-apoptotic protein Bcl-xL in all GM cells and anti-apoptotic Bcl-2 in U87MG cells, thereby shifting the cellular equilibrium from life to death. An increased accumulation of histone H4 was detected in the p21 (WAF-1) promoter and the structural gene (exon 2) and the Bad structural gene (exon 2 and 3) upon treatment with FK228, as assessed by chromatin immunoprecipitation (ChIP) assay. Thus, the results indicated that an increased expression of p21 (WAF1) and Bad due to FK228 is regulated, at least in part, by the degree of acetylation of the gene-associated histone. We also found that FK228 inhibits cellular invasiveness and decreases MMP-2 activity. In addition, the growth of transplanted human GM m-3 cells into the subcutaneous tissue of hereditary athymic mice was significantly inhibited, and apoptosis was induced with FK228 treatment. The results suggested that FK228 might be useful in the treatment of human GM, although further studies will be needed.