miR-580对乳腺癌细胞系中Twist1的调节作用

目的：探讨miR-580在MCF-10A细胞系中对Twist1的调节。方法：本实验利用生物信息学方法预测Twist1的靶miRNA是miR-580。首先,采用qPCR法检测在MCF-10A系列细胞系中Twist1及miR-580的表达。然后,在MCF-10A细胞系中分别转染miR-580类似物和miR-580抑制物后,利用RT-PCR、Western blot、t检验分析Twist1的表达及细胞迁移能力的变化。最后利用荧光素酶实验验证miR-580通过结合在Twist1的3'UTR调节其表达。结果：1)在MCF-10A细胞系中Twist1与miR-580的表达呈负相关;2)在MCF-10A细胞系中转染miR-580类似物后,Twist1的表达下调;在MCF-10A细胞系中转染miR-580抑制物后Twist1的表达上调;3)在MCF-10A细胞系中引入miR-580类似物后细胞迁移能力降低;4)miR-580直接结合在Twist1的3'UTR。结论：miRNA-580在MCF-10A细胞系中通过结合在Twist1的3'UTR负向调节Twist1的表达从而克制细胞的迁移。     

Targeting miR-21 with AS-miR-21 suppresses aggressive growth of human tongue squamous cell carcinoma in vivo

MicroRNAs (miRNAs) are involved in many human malignant tumors. Notably, miR-21 was identified to contribute to tumorigenicity. To investigate the repressive effect of targeting miR-21 with AS-miR-21 on proliferation of tongue squamous cell carcinoma (TSCC). We established the Tca8113-luc cell line with stable luciferase expression using pGL6-luciferase (pGL6-luc) plasmid transfection. TSCC xenograft models were characterized by high tumorigenicity rate and stable growth. Intratumor injection of Oligofectamine™-mediated AS-miR-21 significantly inhibited TSCC growth. The suppression of malignant phenotype was also accompanied by decreased photon signals, rare necrosis foci, smaller nucleuses, weakly stained nucleuses, atypia reversal and tumor angiogenesis reduction. Additionally, miR-21 expression was markedly decreased in TSCC xenografts and the apoptotic index was increased. Intratumor injection of AS-miR-21 into TSCC xenografts could reduce expression of miR-21, promote apoptosis of TSCC cells and inhibit TSCC proliferation.     

Overexpression of miR-221 inhibits proliferation and promotes apoptosis of human astrocytoma cells

microRNAs (miRNAs) play tumor-promoting roles in a variety of tumors. This study investigated the expression of miRNA-211 (miR-221) in human astrocytoma, and its effect on proliferation and apoptosis of human astrocytoma cells in vitro. miR-221 expression was detected in 10 astrocytoma tissues and 4 adjacent tissues by real-time quantitative PCR (qRT-PCR). miR-221 expression in situ was significantly higher in astrocytoma tissues than in adjacent tissues (P<0.05). To determine whether the upregulation of miR-221 could be associated with tumor development or progression, a synthetic miR-221 mimic was transiently transfected into U251 astrocytoma cells in vitro. qRT-PCR confirmed that the mimic significantly increased the expression of miR-221 in these cells. An MTT colorimetric assay indicated that proliferation was significantly higher in U251 cells transfected with miR-221 mimic than in scramble-transfected control cells (P<0.05). Further analysis of miR-221 transfected cells by flow cytometry revealed an altered cell cycle progression, with more cells in S and G1 phase, as well as an inhibition of apoptosis (P<0.05). These findings indicate that the upregulation of miR-221 in astrocytoma tissues may be associated with development or progression of these tumors. Thus, miR-221 should be explored as a potential molecular marker for the diagnosis and treatment of astrocytoma.     

Augmented miR-10b expression associated with depressed expression of its target gene KLF4 involved in gastric carcinoma

Previous studies have revealed several targets of miR-10b, such as syndecan-1, HOXD10, TBX5, and E-cadherin. In this study, we aimed to assess whether Krüppel-like factor 4 (KLF4) is a target gene of miR-10b in gastric cancer (GC). Targeting of KLF4 by miR-10b was confirmed by dual-luciferase reporter assays. The expression levels of miR-10b and KLF4 mRNA in 5 different gastric cancer cell lines and 65 pairs of gastric cancer tissues were detected by Real-time PCR. In addition, KLF4 protein in gastric cancer cell lines and 30 GC tissues was measured by western blotting and immunochemistry, respectively. KLF4 is a direct target gene of miR-10b in GC, and its expression is reduced by miR-10b at both mRNA and protein levels. In addition, the expression level of miR-10b was tendentiously upregulated in GC tissues while the expression levels of KLF4 mRNA and protein were decreased in gastric cancer tissues compared with normal adjacent tissue. There was a dramatically inverse correlation between the expression levels of miR-10b and KLF4 mRNA in GC (r = -0.339, P = 0.006). These findings indicate that miR-10b was upregulated in GC and may have a key role in GC pathogenesis and development through the downregulation of its target gene KLF4.     

HPV-16 E6 promotes cell growth of esophageal cancer via downregulation of miR-125b and activation of Wnt/β-catenin signaling pathway

High-risk human papillomavirus (HPV) is a possible cause of esophageal cancer. However, the molecular pathogenesis of HPV-infected esophageal cancer remains unclear. The expression levels of some microRNAs including miR-125b have been negatively correlated with HPV infection, and miR-125b downregulation is associated with tumorigenesis. In addition, Wnt/β-catenin signaling pathway has been suggested to play an important role in esophageal cancer (EC). We examined miR-125b and Wnt/β-catenin signaling pathway in HPV-16 E6 promoted tumor progression in EC. HPV-16 E6 transfection decreased markedly the expression levels of miR-125b and promoted the colony formation in the Eca 109 and Kyse 150 cell lines, and restoration of miR-125b expression level antagonized the increased colony formation in HPV-16 E6 transfected cell lines. We also demonstrated that overexpression of E6 upregulated the Wnt/β-catenin signaling activity via modulating the multiple regulators including TLE1, GSK3β, and sFRP4. Overexpression of miR-125b restored the expression levels of these proteins. Expression of miR-125b was lower in HPV-16 E6 positive esophageal cancer tissues, and was negatively correlated with E6 mRNA levels. Our results indicate that HPV-16 E6 promotes tumorigenesis in EC via down-regulation of miR-125b, and this underlying mechanism may be involved in the activation of the Wnt/β-catenin signaling pathway.     

MiR-124 effect in neurons apoptosis in newborn rat with thyroid hypofunction

Congenital thyroid hypofunction can cause a variety of developmental disorders. Hippocampus is an important structure participating in the cognitive activities. Neural function damage is able to induce hippocampal neuron apoptosis. As a miRNA expressed specifically and abundantly in brain tissue, miR-124 has protective effect to neuron apoptosis caused by cerebral apoplexy. However, its role in neuron apoptosis caused by thyroid hypofunction is still unclear. The rats were divided into four groups including normal group, thyroid hypofunction group, miR-124 negative control group, and miR-124 mimics group. Propylthiouracil (50 mg/d) was injected to the stomach to the rats with 15 d pregnancy till the newborn rats were born. Inducing the thyroid hypofunction rat model and then injecting miR-124 mimics to ventricle. Serum TSH, FT3 and FT4 were detected to confirm the model. Immunohistochemistry was carried out to calculate neuron number. Tunel assay was used to detect neuron apoptosis. Western blot was applied to detect apoptosis related protein Caspase-3, Bcl-2 and Bax expression. After brain injection miR-124 mimics, hippocampal neuron number and morphology both improved in 15 d newborn mice compared with thyroid hypofunction group. Tunel staining found positive neurons reduced, which indicated that miR-124 can inhibit hippocampal neuron apoptosis in thyroid hypofunction rats. Further Western blot results revealed that apoptosis inhibition might be related to down-regulating activated Caspase-3 and Bax levels, and up-regulating tumor-suppressor gene Bcl-2 expression. MiR-124 can protect neuron apoptosis in thyroid hypofunction rat.     

Predictive role of miR-146a rs2910164 (C>G), miR-149 rs2292832 (T>C), miR-196a2 rs11614913 (T>C) and miR-499 rs3746444 (T>C) in the development of hepatocellular carcinoma

We conducted a case-control study to evaluate the association of miR-146a rs2910164 (C>G), miR-149 rs2292832 (T>C), miR-196a2 rs11614913 (T>C) and miR-499 rs3746444 (T>C) polymorphisms with the risk of hepatocellular carcinoma. A total of 274 patients with HCC were collected between January 2013 and December 2014. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was taken to determine the polymorphism of miR-146a C>G, miR-149 T>C, miR-196a2 T>C and miR-499 T>C. By comparing with control groups, patients with HCC were more likely to be males (OR=2.01, 95% CI=1.38-2.95), have older age (OR=1.52, 95% CI=1.09-2.13), have a history of alcohol drinking (OR=2.09, 95% CI=1.49-2.93), and be infected with HBV (OR=32.98, 95% CI=19.70-55.46) and HCV (OR=56.26, 95% CI=23.28-152.98) infection. By conditional regression analysis, individuals carrying the TC and CC genotypes of miR-196a2 T>C were found to be associated with an elevated risk of HCC compared to the TT genotype, and the adjusted odds ratio were 1.50 (1.03-2.17) and 2.86 (1.60-5.16), respectively. Moreover, the TC+CC genotype was correlated with an increased risk of HCC (OR=1.69, 95% CI=1.19-2.41) compared to the wide-type genotype. In conclusion, our results suggested that miR-196a2 T>C polymorphism is associated with HCC risk in Chinese population.     

抑制卵巢癌A2780/Taxol细胞hsa-miR-27a表达对紫杉醇敏感性影响的研究

目的:研究抑制卵巢癌A2780/Taxol细胞hsa-miR-27a表达对紫杉醇敏感性的影响。方法:用浓度递增法建立卵巢癌耐紫杉醇细胞系A2780/Taxol;Stem-loop real-time PCR技术检测A2780/Taxol及亲本细胞A2780中hsa-miR-27a表达水平;利用脂质体Lipofectamine2000将化学合成的miR-27a抑制物及阴性对照(Negative Control,NC)转染A2780/Taxol细胞;分别用Real-time PCR和蛋白印迹法技术检测MDR1mRNA和P-glyco-protein(P-gp)蛋白表达;MTT检测A2780/Taxol对紫杉醇敏感性的变化;流式细胞术检测细胞内P-gp荧光底物罗丹明123(Rh-123)的荧光强度。结果:(1)成功建立了卵巢癌耐紫杉醇细胞系A2780/Taxol;(2)miR-27a在A2780/Taxol细胞中高表达,与A2780细胞相比,表达增高2.2倍。(3)P-gp蛋白在A2780/Taxol细胞中高表达,在A2780细胞中未检测出其表达;(4)转染miR-27a抑制物后,A2780/Taxol细胞的MDR1mRNA和P-gp表达下降,与转染NC组相比,P-gp表达降低36%;对紫杉醇的敏感性增加,IC50为0.53μmol/L,与转染NC组IC506.8μmol/L相比,有明显差异;(5)流式细胞仪结果显示,细胞内Rh-123荧光强度在转染抑制物的A2780/Taxol细胞为5.10±0.35,与A2780/Taxol细胞的2.95±0.39和转染NC的A2780/Taxol细胞的3.30±0.45相比,差异均有统计学意义。结论:hsa-miR-27a在卵巢癌耐紫杉醇A2780/Taxol细胞中高表达,可能通过间接调节P-gp的表达和功能,参与耐药。抑制miR-27a表达后,可以增加A2780/Taxol细胞对紫杉醇的敏感性,部分逆转耐药。     

Increased risk of polycystic ovary syndrome (PCOS) associated with CC genotype of miR-146a gene variation

Polycystic ovary syndrome (PCOS) is an endocrinopathy in reproductive-age women believed to be affected by several genetics and environmental factors or both. Different miRNAs are one of such genetic factors that their associations with PCOS have been implicated. For instance, miR-146a that is well known for strongly regulating the immune response and inflammation was upregulated in serum plasma, follicular fluid and granulosa cells of PCOS patients. Different studies have shown that genetic changes in pre-miRNA can cause change in the expression or biological function of mature miRNA. Therefore, the main aim of this study was to investigate the association of miR-146a gene variation (rs2910164) with the susceptibility to PCOS. This study consists of 180 patients with PCOS and 192 healthy women matched by age and geographical region. Genotyping were determined by using PCR-RFLP in all subjects. The genotype frequency and allele distributions of all subjects were evaluated using Fisher’s exact test directed by SPSS v.20. The genotype and allele frequencies of the miR-146a polymorphism (rs2910164) significantly differ between PCOS and healthy controls. The frequencies of CC genotype (p?=?.054) and ‘C’ allele (p?=?.0001) of the miR-146a variant indicated a significant incidence in cases compared to controls. Such association was obtained in co-dominant (OR?=?3.16) and dominant (OR?=?2.29) models. Result of this study can be proposed that women with miR-146a variation are at a higher risk for developing PCOS, which can be due to up-regulation of miR-146a.