Activities of E6 Protein of Human Papillomavirus 16 Asian Variant on miR-21 Up-regulation and Expression of Human Immune Response Genes

Background: Variants of human papillomavirus (HPV) show more oncogenicity than do prototypes. TheHPV16 Asian variant (HPV16As) plays a major role in cervical cancer of Asian populations. Some amino acidchanges in the E6 protein of HPV16 variants affect E6 functions such as p53 interaction and host immunesurveillance. This study aimed to investigate activities of HPV16As E6 protein on modulation of expressionof miRNA-21 as well as interferon regulatory factors (IRFs) 1, 3, 7 and c-fos. Materials and Methods: Vectorsexpressing E6 protein of HPV16As (E6D25E) or HPV16 prototype (E6Pro) were constructed and transfected intoC33A cells. HCK1T cells expressing E6D25E or E6Pro were established by transducing retrovirus-containingE6D25E or 16E6Pro. The E6AP-binding activity of E6 and proliferation of the transfected C33A cells weredetermined. MiR-21 and mRNA of interesting genes were detected in the transfected C33A cells and/or theHCK1T cells, with or without treatment by culture medium from HeLa cells (HeLa-CM). Results: E6D25Eshowed binding activity with E6AP similar to that of E6Pro. Interestingly, E6D25E showed a higher activity ofmiR-21 induction than did E6Pro in C33A cells expressing E6 protein. This result was similar to the HCK1Tcells expressing E6 protein, with HeLa-CM treatment. The miR-21 up-regulation significantly corresponded toits target expression. Different levels of expression of IRFs were also observed in the HCK1T cells expressing E6protein. Interestingly, when treated with HeLa-CM, IRFs 1, 3 and 7 as well as c-fos were significantly suppressedin the HCK1T cells expressing E6D25E, whereas those in the HCK1T cells expressing E6Pro were induced. Asimilar situation was seen for IFN-α and IFN-β. Conclusions: E6D25E of the HPV16As variant differed fromthe E6 prototype in its activities on epigenetic modulation and immune surveillance and this might be a keyfactor for the important role of this variant in cervical cancer progression.     

MiR-34b/c rs4938723 Polymorphism Significantly Decreases the Risk of Digestive Tract Cancer: Meta-analysis

Background: Previous studies investigating the association between miR-34b/c rs4938723 polymorphism andcancer risk showed inconclusive. Here, we performed meta-analysis to investigate the association between miR-34b/c rs4938723 polymorphism and digestive cancer risk. Materials and Methods: Literature database includingPubMed, OVID, Chinese National Knowledge Infrastructure (CNKI) were searched for publications concerningthe association between the miR-34b/c rs4938723 polymorphism and digestive cancer risk. Results: A total of 6studies consisting of 3246 cases and 3568 controls were included in this meta-analysis. The combined analysissuggested the miR-34b/c rs4938723 polymorphism significantly reduced digestive cancer risk under allelic model,homogeneous co-dominant model and recessive model (C vs T: OR=0.88, 95%CI=0.82-0.95, p-value=0.001; CCvs TT: OR =0.67, 95%CI=0.57-0.80, p-value=0.000; CC vs TT/TC: OR=0.68, 95%CI=0.58-0.80, p-value=0.000).Q-test and I2 test revealed no significant heterogeneity in all genotype comparisons. The Begger’s funnel plot andEgger’s test did not show significant publication bias. Conclusions: The current evidence supports the conclusionthat the miR-34b/c rs4938723 polymorphism decreases an individual’s susceptibility to digestive cancers.     

Epigenetically silenced miR-34b/c as a novel faecal-based screening marker for colorectal cancer

Background:

MicroRNAs are tiny non-coding small endogenous RNAs that regulate gene expression by translational repression, mRNA cleavage and mRNA inhibition. The aim of this study was to investigate the hypermethylation of miR-34b/c and miR-148a in colorectal cancer, and correlate this data to clinicopathological features. We also aimed to evaluate the hypermethylation of miR-34b/c in faeces specimens as a novel non-invasive faecal-DNA-based screening marker.

Methods:

The 5-aza-2′-deoxycytidine treatment and methylation-specific PCR were carried out to detect the hypermethylation of miR-34b/c and miR-148a.

Results:

The miR-34b/c hypermethylation was found in 97.5% (79 out of 82) of primary colorectal tumours, P=0.0110. In 75% (21 out of 28) of faecal specimens we found a hypermethylation of miR-34b/c while only in 16% (2 out of 12) of high-grade dysplasia. In addition, miR-148a was found to be hypermethylated in 65% (51 out of 78) of colorectal tumour tissues with no significant correlation to clinicopathological features. However, a trend with female gender and advanced age was found, P=0.083. We also observed a trend to lower survival rate in patients with miR-148a hypermethylation with 10-year survival probability: 48 vs 65%, P=0.561.

Conclusions:

These findings show that aberrant hypermethylation of miR-34b/c could be an ideal class of early screening marker, whereas miR-148a could serve as a disease progression follow-up marker.     

MicroRNA-204 increases sensitivity of neuroblastoma cells to cisplatin and is associated with a favourable clinical outcome

Background:Neuroblastoma remains a major cause of cancer-linked mortality in children. miR-204 has been used in microRNA expression signatures predictive of neuroblastoma patient survival. The aim of this study was to explore the independent association of miR-204 with survival in a neuroblastoma cohort, and to investigate the phenotypic effects mediated by miR-204 expression in neuroblastoma.Methods:Neuroblastoma cell lines were transiently transfected with miR-204 mimics and assessed for cell viability using MTS assays. Apoptosis levels in cell lines were evaluated by FACS analysis of Annexin V-/propidium iodide-stained cells transfected with miR-204 mimics and treated with chemotherapy drug or vehicle control. Potential targets of miR-204 were validated using luciferase reporter assays.Results:miR-204 expression in primary neuroblastoma tumours was predictive of patient event-free and overall survival, independent of established known risk factors. Ectopic miR-204 expression significantly increased sensitivity to cisplatin and etoposide in vitro. miR-204 direct targeting of the 3' UTR of BCL2 and NTRK2 (TrkB) was confirmed.Conclusion:miR-204 is a novel predictor of outcome in neuroblastoma, functioning, at least in part, through increasing sensitivity to cisplatin by direct targeting and downregulation of anti-apoptotic BCL2. miR-204 also targets full-length NTRK2, a potent oncogene involved with chemotherapy drug resistance in neuroblastoma.     

miR-19与肿瘤

miR-17～92基因簇编码6种成熟的miRNA,包括miR-17、miR-20a、miR-18a、miR-19a、miR-19b和miR-92a—1,是-类典型的致癌多作用子miRNA。miR-19（包括miR．19a和miR-19b）是其中最重要的致癌miRNA,在淋巴瘤、白血病、肺癌、乳腺癌、多发性骨髓瘤等肿瘤中均表达上调,成为研究的热点之-。miR-19可通过抑制靶基因如PTEN、PP2A、Bim、SOCS1等促进肿瘤的增殖、侵袭和转移,与P13K—AKT-mTOR信号转导通路关系密切,在肿瘤的发生发展中起着非常重要的作用。     

MicroRNA-409-3p regulates cell proliferation and apoptosis by targeting PHF10 in gastric cancer

Recently, we have identified GSK-3 as a new therapeutic target in renal cell cancer (RCC). miR-199a could potentially downregulate GSK-3β expression. Here, we found a decreased miR-199a expression in 59% (32 of 54) of RCCs and it was correlated with higher tumor stage (p < 0.05) and nuclear overexpression of GSK-3β (p < 0.05). We show that re-expression of miR-199a downregulates GSK-3β and suppresses cancer cell growth. Our results demonstrate low miR-199a expression as a feature of advanced RCCs, identify miR-199a as a negative regulator of GSK-3β, and suggest re-expression of pre-miR-199a as a new potential treatment of RCC.     

miR-21 functionally interacts with the 3'UTR of chemokine CCL20 and down-regulates CCL20 expression in miR-21 transfected colorectal cancer cells

As deregulation of miRNAs and chemokine CCL20 was shown to play a role in colorectal cancer (CRC) pathogenesis, we analyzed the functional interactions of candidate miRNAs with CCL20 mRNA. After target prediction software programs indicated a role for miR-21 in CCL20 regulation, we applied the luciferase reporter assay system to demonstrate that miR-21 functionally interacts with the 3′UTR of CCL20 mRNA and down-regulates CCL20 in miR-21 mimic transfected CRC cell lines (Caco-2, SW480 and SW620). Thus, regulation of CCL20 expression by miR-21 might be a regulatory mechanism involved in progression of CRC.     

Stress Response of Glioblastoma Cells Mediated by miR-17-5p Targeting PTEN and the Passenger Strand miR-17-3p Targeting MDM2

Tumor development not only destroys the homeostasis of local tissues but also the whole body, and thus the tumor cells have to face the body''s defense system, a shortage of nutrition and oxygen, and chemotherapeutic drug treatment. In response to these stresses, tumor cells often alter gene expression and microRNA levels to facilitate survival. We have demonstrated that glioblastoma cells deprived of nutrition or treated with chemotherapeutics drugs expressed increased levels of miR-17. Ectopic transfection of miR-17 prolonged glioblastoma cell survival when the cells were deprived with nutrition or treated with chemotherapeutic drugs. Expression of miR-17 also promoted cell motility, invasion, and tube-like structure formation. We found that these phenotypes were the results of miR-17 targeting PTEN. As a consequence, HIF1&alpha; and VEGF were up-regulated. Ectopic expression of miR-17 was found to facilitate enrichment of stem-like tumor cells, since the cells became drug-resistant, showed increased capacity to form colonies and neurospheres, and expressed higher levels of CD133, a phenotype similar to ectopic expression of HIF1&alpha;. To further confirm the phenotypic property of stem cells, we demonstrated that glioblastoma cells transfected with miR-17 proliferated slower in different nutritional conditions by facilitating more cells staying in the G1 phase than the control cells. Finally, we demonstrated that miR-17 could repress MDM2 levels, resulting in decreased cell proliferation and drug-resistance. Our results added a new layer of functional mechanism for the well-studied miRNA miR-17.     

miR-34a调控HEK293细胞自噬作用的初步研究

目的探讨miR-34a对HEK293细胞自噬作用的影响。方法采用miR-34a模拟物(模拟物组)和miR-34a抑制剂(抑制剂组)分别转染HEK293细胞,并设空白对照(对照组)。采用定量PCR检测miR-34a、p53基因表达的变化,Western blotting检测自噬相关蛋白LC3Ⅱ及p53表达的变化,并采用生物信息学方法分析miR-34a对自噬相关基因(Atg6/beclin1、sestrin2、FoxO3等)的可能作用。结果定量PCR结果显示,模拟物组miR-34a表达显著上调(P<0.05),抑制剂组miR-34a表达显著下调(P<0.05)。与对照组相比,miR-34a模拟物可显著抑制HEK293细胞LC3Ⅱ蛋白的表达(P<0.05),而miR-34a抑制剂则显著上调HEK293细胞LC3Ⅱ蛋白的表达(P<0.05)。定量PCR和Western blotting结果显示,各组p53mRNA及蛋白表达无统计学差异。生物信息学分析显示,Atg6/beclin1、sestrin2、FoxO3等自噬相关基因是miR-34a潜在的靶基因。结论miR-34a能抑制HEK293的自噬作用,可能是通过直接抑制...