MicroRNA-126与胃癌患者放化综合治疗效果的关系及其对胃癌SGC-7901细胞的放射增敏作用

目的:研究microRNA-126与胃癌患者放化综合治疗疗效的关系及其对胃癌细胞的放射增敏效果。方法:选取2014年6月~2015年6月间我院收治的晚期胃癌患者60例为研究对象,其中男性32例,女性28例,年龄37~65岁,平均年龄(51±7)岁。所有患者均接受放化综合治疗。收集患者的胃癌病理组织标本,同时于治疗结束时采集静脉血标本。采用国际实体瘤疗效评价标准(RECIST)评价患者的近期疗效,根据疗效将患者分为治疗敏感组和非敏感组。实时荧光定量PCR检测各组患者组织及血浆中microRNA-126的表达变化。体外培养胃癌SGC-7901细胞并转染microRNA-126 mimic;平板集落形成实验分析microRNA-126 mimic转染对SGC-7901细胞放射敏感性的影响;流式细胞术检测转染microRNA-126 mimic对SGC-7901细胞凋亡率的影响。结果:根据RECIST,共28例患者对治疗敏感,32例患者对治疗不敏感。与敏感组患者相比,不敏感组患者血浆和胃癌组织中的microRNA-126相对水平较低,相对于敏感组的倍数分别为0.72±0.04和0.48±0.03,差异具有统计学意义(P0.05)。MicroRNA-126 mimic转染后SGC-7901细胞的SF_2值和D_0值减小(P0.05),增敏比为1.74。流式细胞术分析结果发现,microRNA-126 mimic转染可以诱导SGC-7901细胞凋亡,并增加射线引起的细胞凋亡。结论:较低的microRNA-126提示胃癌患者放化综合治疗疗效不佳;microRNA-126具有增加胃癌细胞放射敏感性的作用。     

miRNA-21减轻氧糖剥夺对PC12细胞的损伤

目的:探讨微小RNA(miRNA)-21对低氧缺血损伤PC12细胞的影响。方法:体外培养PC12细胞,建立氧糖剥夺(OGD)损伤模型。细胞随机分为对照组、OGD组、阴性对照序列+OGD组、miRNA-21 inhibitor+OGD组和miRNA-21 mimic+OGD组。通过采用CCK-8、real-time PCR、Western blot等技术探讨miRNA-21对OGD损伤PC12细胞的影响和机制。结果:降低miRNA-21的表达,受OGD损伤的PC12细胞活力明显下降;增加miRNA-21的表达,受OGD损伤的PC12细胞活力明显增加。进一步发现miRNA-21促进OGD损伤PC12细胞的AKT磷酸化。结论:miRNA-21明显增加OGD损伤PC12细胞的活力,其机制可能与激活PI3K/AKT信号通路有关。     

miRNA-93在急性淋巴细胞白血病中的表达

目的:探讨微小RNA(miRNA)-93在急性淋巴细胞白血病中的表达情况及其对急性T细胞白血病细胞株Jurkat增殖的影响和潜在作用机制。方法:Real-time PCR技术检测急性白血病患者骨髓样本中miRNA-93的表达水平。转染miRNA-93 inhibitor下调Jurkat细胞中miRNA-93的表达,分别采用CCK-8法、Ed U法和流式细胞术检测细胞活力、增殖及周期,Western blot检测周期相关调控因子cyclin D1、细胞周期蛋白依赖性激酶4(CDK4)、p-Rb及P27的蛋白表达水平。结果:miRNA-93在急性白血病患者中呈现高表达,且在高危患者中表达水平最高;沉默miRNA-93后,Jurkat细胞的活力下降并出现明显的G1/S期阻滞,同时细胞中cyclin D1、CDK4、p-Rb的蛋白水平显著降低,而P27的蛋白水平显著升高。结论:miRNA-93在急性淋巴细胞白血病中表达显著升高;沉默miRNA-93可通过调控周期相关因子的表达抑制急性T细胞白血病细胞株Jurkat的增殖。     

白藜三醇通过下调microRNA-21减轻快速电刺激所致心房肌细胞电重构

目的:研究白藜三醇(resveratrol,RSV)对快速电刺激(rapid electrical stimulation,RES)导致乳鼠心房肌细胞电重构时微小RNA-21(microRNA-21,miR-21)表达的影响,探讨RSV通过miR-21参与电重构的可能机制。方法:采用胰酶、Ⅰ型胶原酶双酶法及差速贴壁法分离培养乳鼠心房肌细胞。通过RES建立乳鼠心房肌细胞房颤模型,心房肌细胞随机分为4组:空白对照(control)组、RSV组、RES组和RSV+RES组。为了证实RSV是否通过调控miR-21的表达参与电重构,除了上述4组,另增加过表达和沉默miR-21组:RES+阴性对照组(RES+NC组)、RES+miR-21 mimics组、RES+miR-21 mimics+RSV组、RES+miR-21 inhibitor组和RES+miR-21 inhibitor+RSV组。CCK-8法检测心房肌细胞活性以确定RSV最佳作用浓度及时间,q PCR法检测各组细胞内miR-21及L型钙离子通道CACNA1C、CACNB2 mRNA的表达水平,Western blot检测L型钙离子通道Cav1.2和Cavβ_2 的蛋白表达水平。结果:与control组相比,RES组miR-21表达明显上调(P0.05),加入RSV预处理后miR-21表达下调(P0.05)。与RES+miR-21 mimics组相比,RES+miR-21 mimics+RSV组miR-21表达下调(P0.05),而CACNA1C和CACNB2 mRNA及Cav1.2和Cavβ_2 蛋白表达量增加(P0.05)。与RES组比,RES+miR-21 inhibitor和RES+miR-21 inhibitor+RSV组的miR-21表达下调(P0.05),CACNA1C和CACNB2 mRNA及Cav1.2和Cavβ_2 蛋白表达量增加,但RES+miR-21 inhibitor组与RSV+RES组比,miR-21表达、CACNA1C和CACNB2 mRNA及Cav1.2和Cavβ_2 蛋白表达量的差异无统计学显著性。结论:在快速电刺激乳鼠心房肌细胞模拟房颤模型中,RSV干预可能通过下调miR-21表达而调控其下游靶基因这一途径来减轻心房肌细胞电重构。     

Biological significance of miR-126 expression in atrial fibrillation and heart failure

We investigated the biological significance of microRNA-126 (miR-126) expression in patients with atrial fibrillation (AF) and/or heart failure (HF) to examine the possible mechanism of miR-126-dependent AF and development of HF. A total of 103 patients were divided into three groups: AF group (18 men and 17 women, mean age: 65.62±12.72 years), HF group (17 men and 15 women, mean age: 63.95±19.71 years), and HF-AF group (20 men and 16 women, mean age: 66.56±14.37 years). Quantitative real-time PCR was used to measure relative miR-126 expression as calculated by the 2−ΔΔCt method. miR-126 was frequently downregulated in the 3 patient groups compared with controls. This reduction was significantly lower in permanent and persistent AF patients than in those with paroxysmal AF (P<0.05, t-test). Moreover, miR-126 expression was markedly lower in the HF-AF group compared with the AF and HF groups. The 3 patient groups had higher N-terminal prohormone brain natriuretic peptide (NT-proBNP) levels, lower left ventricular ejection fraction (LVEF), larger left atrial diameter, and higher cardiothoracic ratio compared with controls. There were significant differences in NT-proBNP levels and LVEF among the AF, HF, and HF-AF groups. Pearson correlation analysis showed that relative miR-126 expression was positively associated with LVEF, logarithm of NT-proBNP, left atrial diameter, cardiothoracic ratio, and age in HF-AF patients. Multiple linear regression analysis showed that miR-126 expression was positively correlated with LVEF, but negatively correlated with the logarithm of NT-pro BNP and the cardiothoracic ratio (all P<0.05). Serum miR-126 levels could serve as a potential candidate biomarker for evaluating the severity of AF and HF. However, to confirm these results, future studies with a larger and diverse patient population are necessary.     

Temozolomide resistance in glioblastoma occurs by miRNA-9-targeted PTCH1, independent of sonic hedgehog level

Glioblastoma Multiforme (GBM), the most common and lethal adult primary tumor of the brain, showed a link between Sonic Hedgehog (SHH) pathway in the resistance to temozolomide (TMZ). PTCH1, the SHH receptor, can tonically represses signaling by endocytosis. We asked how the decrease in PTCH1 in GBM cells could lead to TMZ-resistance. TMZ resistant GBM cells have increased PTCH1 mRNA and reduced protein. Knockdown of Dicer, a Type III RNAase, indicated that miRNAs can explain the decreased PTCH1 in TMZ resistant cells. Computational studies, real-time PCR, reporter gene studies, western blots, target protector oligos and ectopic expression identified miR-9 as the target of PTCH1 in resistant GBM cells with concomitant activation of SHH signaling. MiR-9 mediated increases in the drug efflux transporters, MDR1 and ABCG2. MiR-9 was increased in the tissues from GBM patients and in an early passage GBM cell line from a patient with recurrent GBM but not from a naïve patient. Pharmacological inhibition of SHH signaling sensitized the GBM cells to TMZ. Taken together, miR-9 targets PTCH1 in GBM cells by a SHH-independent method in GBM cells for TMZ resistance. The identified pathways could lead to new strategies to target GBM with combinations of drugs.     

微RNA-155激动剂对脓毒症小鼠肝损伤时炎症应答的影响

目的探讨微RNA-155（miR-155）激动剂对脓毒症小鼠肝损伤时炎症应答的影响。 方法将80只雄性小鼠分成假手术组、脓毒症组、微RNA（miRNA）组及miR-155组,每组各20只。以盲肠结扎穿孔（CLP）术制备脓毒症小鼠模型,假手术组除不结扎和穿刺盲肠外,其余手术步骤相同。建模成功后48 h,miRNA组、miR-155组小鼠分别经尾静脉注射miRNA、miR-155激动剂,假手术组和脓毒症组注射等量等渗NaCl溶液。每组取10只用于观察小鼠活动状态及术后7 d存活情况;每组另取10只于术后5 d采集外周血,检测并比较miR-155及丙氨酸转氨酶（ALT）水平;采用酶联免疫吸附测定（ELISA）检测血清白细胞介素10（IL-10）及肿瘤坏死因子α（TNF-α）水平。 结果CLP术后7 d,miR-155组小鼠均死亡,脓毒症组和miRNA组仍有2只存活;而假手术组小鼠10只均存活。CLP术后5 d,4组小鼠间miR-155、ALT、IL-10及TNF-α水平比较,差异均有统计学意义（F = 46.536,P < 0.001;F = 39.194,P = 0.002;F = 39.228,P = 0.002;F = 83.400,P < 0.001）。进一步两两比较发现,脓毒症组、miRNA组及miR-155组小鼠的miR-155、ALT、IL-10及TNF-α水平均显著高于假手术组（P均< 0.05）,且与脓毒症组和miRNA组比较,miR-155组小鼠的miR-155、ALT及IL-10水平均较高,而TNF-α水平均较低（P均< 0.05）。 结论miR-155激动剂可提高IL-10水平,降低TNF-α水平,从而加重脓毒症小鼠的肝损伤。     

微小RNA-494通过抑制Survivin诱导前列腺癌PC-3细胞凋亡

目的 观察微小RNA( miRNA) -494对人前列癌PC-3细胞中Survivin基因的表达抑制及对PC-3细胞增殖与凋亡的影响.方法 TargetScan 5.2预测miRNA-494与Survivin mRNA配对评分为mirSVR score:-0.4916、PhastCons score:0.4876;定量聚合酶链反应(qPCR)分析PC-3相对于正常前列腺上皮细胞株RWPE-1中miRNA-494的上下调情况;构建过表达miRNA-494的腺病毒载体,应用逆转录-聚合酶链反应(RT-PCR)、Western blot、噻唑蓝(MTT)法、流式细胞仪分析分别检测感染前后Survivin基因及蛋白的表达差异、细胞增殖及生长周期和凋亡变化.结果 miRNA-494在PC-3中的表达为RWPE-1中的(0.547±0.032)倍;Ad-pre-miRNA-494构建成功;实验组细胞增殖抑制呈现时间依赖性;和对照组比较,72 h后实验组Survivin蛋白表达为(21.69±4.62)％,与空载体组比较,差异有统计学意义(P＜0.01),流式细胞仪检测结果显示实验组PC-3细胞G2/M期阻滞率及细胞凋亡率显著增加.结论 miRNA-494通过抑制前列腺癌PC-3细胞中Survivin基因的表达而诱导前列腺癌PC-3凋亡.     

上调miRNA-133a表达对心肌缺血再灌注损伤的保护作用

目的 观察上调miRNA-133a表达是否可改善缺血再灌注损伤后心肌损害及心脏功能.方法 建立活体大鼠心肌缺血再灌注损伤模型.将实验动物随机分为5组:(1)空白对照组(Sham组);(2)缺血再灌注损伤组(I/R组);(3)缺血再灌注损伤+miRNA-133a模拟物agomiR-133a组(I/R+ agomiR-133a组);(4)缺血再灌注损伤+阴性对照序列组(I/R+ scramble组);(5)缺血再灌注损伤组+生理盐水组(I/R+ NS组).于再灌注24h分别使用实时定量聚合酶链反应(Real-TimePCR)法检查心肌内miRNA-133a表达水平;经胸超声心动检查大鼠心脏功能;2,3,5-氯化三苯基四氮唑(TTC)染色检测心肌梗死以及TdT介导的dUTP缺口末端标记(TUNEL)检测心肌细胞凋亡.结果 I/R+ agomiR-133a组心肌内miRNA表达水平显著高于I/R组(P＜0.01).上调miRNA-133a表达水平可显著减少再灌注后心肌梗死面积[(37.0±3.1)％比(58.0±4.4)％,P＜0.01],抑制心肌细胞凋亡(38.4±6.0比15.7±5.2,P＜0.01),并改善心脏功能[LVEF:(64.8 ±2.9)％比(52.8±4.0)％,LVFS:(31.1±1.2)％比(25.2±0.8)％,P＜0.01].NS与scramble对再灌注后心肌损伤及心脏功能无显著影响.结论 上调心肌内miRNA-133a表达水平可显著减轻缺血再灌注损伤24h后心肌损害,并改善心脏功能.