microRNA-18a Promotes Cell Migration and Invasion Through Inhibiting Dicer l Expression in Hepatocellular Carcinoma In Vitro / 中国医学科学杂志(英文版)

Objective To investigate the effects of microRNA-18a (miR-18a) on migration and invasion of hepatocellular carcinoma (HCC) cells, and its possible mechanism associated with Dicer l.Methods HepG2 and HepG2.2.15 cells were transfected with miR-18a inhibitor using Lipofectamine. Cell invasion was evaluated by transwell invasion assay, and cell migration was detected by transwell migration and wound-healing assays. Moreover, luciferase reporter assay was used to identify whether Dicer expression was regulated by miR-18a. Real-time RT-PCR and western blot were performed to analyze Dicer 1 expression. In addition, a functional restoration assay was performed to investigate whether miR-18a promotes HCC cell migration and invasion by directly targeting Dicer 1.Results miR-18a inhibitor can suppress the migration and invasion of HCC cells. Furthermore, suppression of Dicer l expression by small interfering RNA essentially abolished the inhibition of cell migration and invasion induced by miR-18a inhibitor, restorating these activities to levels similar to the parental HCC cells. Interestingly, suppression of miR-18a in HCC cells resulted in enhanced expression of Dicer l. In addition, the results of a luciferase assay demonstrated targeted regulation of Dicer l by miR-18a.Conclusion Our findings suggest that miR-18a promotes migration and invasion of HCC cells by inhibiting Dicer l expression.

Dicer gene expression as a prognostic factor in acute lymphoblastic leukemia and chronic lymphocytic leukemia in pars province

Alterations in the expression of microRNAs [miRNAs] have been proposed to play a role in the pathogenesis of acute lymphoblastic leukemia [ALL] and chronic lymphocytic leukemia [CLL]. Dicer is one of the main regulators of miRNA biogenesis, and deregulation of its expression has been indicated as a possible cause of miRNA alterations observed in various cancers. Our aim was to analyze the expression of the Dicer protein and its relationship with ALL and CLL. This cross-sectional study was performed from 2010 to 2012 in Shahid Faghihi Hospital, Shiraz, Iran. In this study, 30 patients with CLL, 21 patients with ALL, 10 child healthy donors, and 19 adult healthy donors were recruited. The patients' samples were checked via flow cytometry, immunohistochemistry, and immunocytochemistry. The controls' samples were also examined in the hematology ward. Total RNA was extracted from the bone marrow and peripheral blood samples of the patients and controls. Then, reverse-transcription polymerase chain reaction was used to estimate the level of Dicer miRNA. The outcomes of the expression analysis of Dicer revealed statistically significant differences between the ALL patients/child healthy controls [meaniSD, 0.19 +/- 0.28vs. 0.73 +/- 0.12; P<0.001] and the CLL patients/adult healthy controls [mean +/- SD, 0.24 +/- 0.25 vs. 0.41 +/- 0.28; P=0.033]. This is the first piece of evidence showing that the expression of the Dicer gene greatly decreased in the patients with ALL in comparison to the child controls. The expression of the Dicer gene was also downregulated in the patients with CLL compared to the adult controls. Given the above findings, the expression of Dicer may play an important role in the progression and prognosis of these diseases

Association of polymorphisms of miRNA biogenesis related genes DICER and DROSHA with azoospermia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the association of polymorphisms of miRNA biogenesis related genes DICER and DROSHA with azoospermia.</p><p><b>METHODS</b>For 330 patients with primary azoospermia and 282 fertile male controls, single nucleotide polymorphisms (SNPs) of DICER rs3742330 and DROSHA rs10719 were determined with a restriction fragment length polymorphism (RFLP) method.</p><p><b>RESULTS</b>For the SNP rs3742330, the frequency of A allele was higher among azoospermia patients compared with the controls (72.0% vs.64.4%, P=0.004), and so was the frequency of AA genotype (53.0% vs. 41.8%, P=0.027, OR=1.829, 95%CI: 1.071-3.124). On the other hand, the allelic and genotypic frequencies of rs10719 did not differ between the two groups (all P > 0.05).</p><p><b>CONCLUSION</b>Polymorphisms of rs3742330 of the DICER gene, particularly the AA genotype, may be associated with azoospermia.</p>

Vascular Response of Ruthenium Tetraamines in Aortic Ring from Normotensive Rats / Resposta Vascular de Tetra-Aminas de Rutênio em Anéis de Aorta de Ratos Normotensos

Background: Ruthenium (Ru) tetraamines are being increasingly used as nitric oxide (NO) carriers. In this context, pharmacological studies have become highly relevant to better understand the mechanism of action involved. Objective: To evaluate the vascular response of the tetraamines trans-[RuII(NH3)4(Py)(NO)]3+, trans-[RuII(Cl)(NO) (cyclan)](PF6)2, and trans-[RuII(NH3)4(4-acPy)(NO)]3+. Methods: Aortic rings were contracted with noradrenaline (10−6 M). After voltage stabilization, a single concentration (10−6 M) of the compounds was added to the assay medium. The responses were recorded during 120 min. Vascular integrity was assessed functionally using acetylcholine at 10−6 M and sodium nitroprusside at 10−6 M as well as by histological examination. Results: Histological analysis confirmed the presence or absence of endothelial cells in those tissues. All tetraamine complexes altered the contractile response induced by norepinephrine, resulting in increased tone followed by relaxation. In rings with endothelium, the inhibition of endothelial NO caused a reduction of the contractile effect caused by pyridine NO. No significant responses were observed in rings with endothelium after treatment with cyclan NO. In contrast, in rings without endothelium, the inhibition of guanylate cyclase significantly reduced the contractile response caused by the pyridine NO and cyclan NO complexes, and both complexes caused a relaxing effect. Conclusion: The results indicate that the vascular effect of the evaluated complexes involved a decrease in the vascular tone induced by norepinephrine (10−6 M) at the end of the incubation period in aortic rings with and without endothelium, indicating the slow release of NO from these complexes and suggesting that the ligands promoted chemical stability to the molecule. Moreover, we demonstrated that the association of Ru with NO is more stable when the ligands pyridine and cyclan ...

Fundamento: As tetra-aminas de rutênio cada vez mais se destacam como carreadoras da molécula de óxido nítrico. Desse modo, estudos farmacológicos tornam-se altamente relevantes, afim de melhor compreender o mecanismo de ação envolvido. Objetivo: Avaliar a resposta vascular das tetra-aminas trans-[RuII(NH3)4(Py)(NO)]3+, trans-[RuII(Cl)(NO)(Cyclan)](PF6)2 e trans-[RuII(NH3)4(4-acPy)(NO)]3+. Métodos: Anéis de aorta foram pré-contraídos com noradrenalina (10-6M). Após estabilização da tensão, concentração única (10-6M) dos compostos foi adicionada ao banho de incubação. As respostas foram registradas ao longo de 120 minutos. A integridade vascular foi avaliada funcionalmente (acetilcolina 10-6M; nitroprussiato de sódio 10-6M) e histologicamente Resultados: A análise histológica confirmou a presença ou não de células endoteliais nos tecidos analisados. Todos os complexos alteraram a resposta contrátil induzida pela noradrenalina, resultando em aumento de tônus seguido de efeito relaxante. Em anéis com endotélio, a inibição do óxido nítrico endotelial causou redução do efeito contrátil da piridina óxido nítrico. Não foram observadas respostas significativas em anéis com endotélio referente ao composto cyclan óxido nítrico. Por outro lado, em anéis sem endotélio, a inibição da guanilato ciclase reduziu significativamente a resposta contrátil dos complexos piridina óxido nítrico e cyclan óxido nítrico, levando ambos os compostos a um efeito relaxante. Conclusão: Os resultados obtidos demonstram que o efeito vascular dos complexos avaliados apresentaram diminuição no tônus vascular induzido pela noradrenalina (10-6M) ao final do tempo de incubação, em anéis com e sem endotélio, indicando liberação lenta da molécula de óxido nítrico do composto estudado e sugerindo que os ligantes causaram estabilidade química à molécula. Demonstramos que a ligação rutênio óxido nítrico é mais estável quando utilizamos os ligantes piridina e cyclan para a formulação ...

Progress in studies on the relationship between Dicer and ovarian tumor / 中南大学学报(医学版)

MiRNAs are short, noncoding RNAs that modulate gene expression at the posttranscriptional level and induce the degradation of the mRNA transcript or the inhibition of protein translation. Dicer is an endoribonuclease in the RNase III family that is essential for the production of miRNAs. The abnormal expression of Dicer is frequently found in the occurrence and development process of many kinds of tumors, which is closely related to the treatment and prognosis of tumor.

Effect of estrogen or progesterone combined with paclitaxel on human ovarian cancer cell growth and Drosha expression / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of estrogen (E2), progesterone(P4), and paclitaxel (taxol) on the growth of primary human ovarian cancer cells in vitro and the expression of Drosha.</p><p><b>METHODS</b>Human ovarian cancer cells were treated with estrogen, progesterone or in combination with paclitaxel in vitro. The inhibition rate of ovarian cancer cells was assessed by methyl thiazolyl tetrazolium (MTT) assay. Apoptosis rate and cell cycle were determined by FACS analysis. The relative abundence of Drosha expression was detected by real-time quantitative PCR (qRT-PCR) and Western blotting.</p><p><b>RESULTS</b>The inhibition rate of the estrogen group, progesterone group, paclitaxel group, E2(+)Taxol group, P4(+)Taxol group was (31.53 ± 8.21)%, (25.22 ± 15.50)%, (46.71 ± 4.25)%, (69.46 ± 3.71)%, and (47.35 ± 39.02)%, respectively, significantly higher than that of the control group (0%, P<0.05 for all). Relative to the ER (-) in ovarian cancer cells,Drosha mRNA expression level of estrogen group, progesterone group, paclitaxel group, E2(+) Taxol group,and P4(+)Taxol group was 1.62 ± 0.10,1.60 ± 0.10,1.75 ± 0.16,1.95 ± 0.20, and 1.53 ± 0.06, respectively, significantly higher than that of the control group (1.00, P<0.05 for all). Relative to the ER (+)in ovarian cancer cells,the Drosha mRNA expression level of estrogen group, progesterone group, paclitaxel group, E2(+)taxol group, and P4(+)Taxol group was 1.03 ± 0.14, 1.60 ± 0.09, 1.75 ± 0.16, 1.60 ± 0.10, 1.53 ± 0.06, respectively except estrogen group, significantly higher than that of the control group (1.00, P<0.05). Relative to the ER (-) in ovarian cancer cells, the Drosha protein expression levels of the control group, estrogen group, progesterone group, paclitaxel group, E2(+) taxol group, and P4(+) Taxol group were 0.25 ± 0.05, 0.87 ± 0.30, 0.85 ± 0.38, 1.30 ± 0.21, 1.75 ± 0.83, 1.62 ± 0.82, respectively, with a significant difference between the experimental groups and the control group (P<0.05). Relative to the ER(+)ovarian cancer cells, the Drosha protein expression levels in the estrogen group, progesterone group, paclitaxel group, E2(+) taxol group, and P4(+) taxol group, were 0.28 ± 0.16, 0.85 ± 0.38, 1.30 ± 0.21, 0.94 ± 0.18, and 1.62 ± 0.82, respectively except estrogen group, significantly higher than that of the control group (0.25 ± 0.05, P<0.05 for all).</p><p><b>CONCLUSIONS</b>Estrogen and progesterone in combination with paclitaxel can inhibit the growth of human ovarian cancer cells in vitro, and affect the cell apoptosis rate. Estrogen and taxol can alter the cell cycle. Estrogen and progesterone combined with paclitaxel show tumor suppressing or sensitizing effect through upregulated Drosha expression, and are associated with the estrogen receptor expression.</p>

Structure of precursor microRNA's terminal loop regulates human Dicer's dicing activity by switching DExH/D domain

Almost all pre-miRNAs in eukaryotic cytoplasm are recognized and processed into double-stranded microRNAs by the endonuclease Dicer protein comprising of multiple domains. As a key player in the small RNA induced gene silencing pathway, the major domains of Dicer are conserved among different species with the exception of the N-terminal components. Human Dicer's N-terminal domain has been shown to play an auto-inhibitory function of the protein's dicing activity. Such an auto-inhibition can be released when the human Dicer protein dimerizes with its partner protein, such as TRBP, PACT through the N-terminal DExH/D (ATPase-helicase) domain. The typical feature of a pre-miRNA contains a terminal loop and a stem duplex, which bind to human Dicer's DExH/D (ATPase-helicase) domain and PAZ domain respectively during the dicing reaction. Here, we show that pre-miRNA's terminal loop can regulate human Dicer's enzymatic activity by interacting with the DExH/D (ATPase-helicase) domain. We found that various editing products of pre-miR-151 by the ADAR1P110 protein, an A-to-I editing enzyme that modifies pre-miRNAs sequence, have different terminal loop structures and different activity regulatory effects on human Dicer. Single particle electron microscopy reconstruction revealed that pre-miRNAs with different terminal loop structures induce human Dicer's DExH/D (ATPase-helicase) domain into different conformational states, in correlation with their activity regulatory effects.

Reduced expression of Diceri is associated with poor prognosis in patients with nasopharyngeal carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#Dicerl plays an important role in generation of microRNA, the purpose of this study was to evaluate Dicerl expression and its prognostic value in nasopharyngeal carcinoma (NPC).@*METHOD@#The protein expression of Dicerl was examined by immunohistochemistry in 276 NPC specimens, and the mRNA levels of Dicerl were analyzed by qRT-PCR in 56 NPC and 11 nasopharyngitis tissues. Cox regression analysis was used to identify independent prognostic factors, and a prognostic score model was constructed for survival prediction.@*RESULT@#Expression of Dicerl was downregulated in NPC tissues at both the mRNA and the protein levels, and there was a notable positive correlation between the expression levels of Dicerl mRNA and protein. Low Dicerl expression was positively correlated with distant metastasis (P<0. 01) and death (P<0. 05). In addition, low expression of Dicerl was significantly associated with poorer overall survival (HR = 2. 32, 95% CI: 1. 30 ~ 4. 14, P<0. 01) and poorer distant metastasis-free survival (HR = 2. 56, 95% CI: 1. 39 ~ 4. 74, P<0. 01). Furthermore, multivariate analysis showed that low expression of Dicerl and tumor-node-metastasis (TNM) stage were independent prognostic indicators for NPC patients. A prognostic score model combining the Dicerl expression and TNM stage had a better prognostic value than the TNM stage alone model or Dicer) expression alone model (P< 0. 05).@*CONCLUSION@#Dicerl was downregulated in NPC tissues at both the mRNA and the protein levels, and low expression of Dicerl could be served as novel prognostic biomarker for NPC patients.

Dicer Is Down-regulated and Correlated with Drosha in Idiopathic Sudden Sensorineural Hearing Loss

Previously, we reported the expression levels of specific microRNA machinery components, DGCR8 and AGO2, and their clinical association in patients with idiopathic sudden hearing loss (SSNHL). In the present study, we investigated the other important components of microRNA machinery and their association with clinical parameters in SSNHL patients. Fifty-seven patients diagnosed with SSNHL and fifty healthy volunteers were included in this study. We evaluated mRNA expression levels of Dicer and Drosha in whole blood of patients with SSNHL and the control group, using RT & real-time PCR analysis. The Dicer mRNA expression level was down-regulated in patients with SSNHL. However, the Drosha mRNA expression level was not significantly altered in patients with SSNHL. Neither the Dicer nor Drosha mRNA expression level was not associated with any clinical parameters, including age, sex, duration of initial treatment from onset (days), initial Pure tone average, Siegel's criteria, WBC, and Erythrocyte sedimentation rate. However, mRNA expression levels of Dicer and Drosha were positively correlated to each other in patients with SSNHL. In this study, we demonstrated for the first time that the Dicer mRNA expression level was down-regulated in patients with SSNHL, suggesting its important role in pathobiology of SSNHL development.

MicroRNA-103a-3p controls proliferation and osteogenic differentiation of human adipose tissue-derived stromal cells

The elucidation of the molecular mechanisms underlying the differentiation and proliferation of human adipose tissue-derived stromal cells (hADSCs) represents a critical step in the development of hADSCs-based cellular therapies. To examine the role of the microRNA-103a-3p (miR-103a-3p) in hADSCs functions, miR-103a-3p mimics were transfected into hADSCs in order to overexpress miR-103a-3p. Osteogenic differentiation was induced for 14 days in an osetogenic differentiation medium and assessed by using an Alizarin Red S stain. The regulation of the expression of CDK6 (cyclin-dependent kinase 6), a predicted target of miR-103a-3p, was determined by western blot, real-time PCR and luciferase reporter assays. Overexpression of miR-103a-3p inhibited the proliferation and osteogenic differentiation of hADSCs. In addition, it downregulated protein and mRNA levels of predicted target of miR-103a-3p (CDK6 and DICER1). In contrast, inhibition of miR-103a-3p with 2'O methyl antisense RNA increased the proliferation and osteogenic differentiation of hADSCs. The luciferase reporter activity of the construct containing the miR-103a-3p target site within the CDK6 and DICER1 3'-untranslated regions was lower in miR-103a-3p-transfected hADSCs than in control miRNA-transfected hADSCs. RNA interference-mediated downregulation of CDK6 and DICER1 in hADSCs inhibited their proliferation and osteogenic differentiation. The results of the current study indicate that miR-103a-3p regulates the osteogenic differentiation of hADSCs and proliferation of hADSCs by direct targeting of CDK6 and DICER1 partly. These findings further elucidate the molecular mechanisms governing the differentiation and proliferation of hADSCs.

Association of microRNA-related genes (DROSHA, DICER1 and GEMIN4) polymorphisms with T-cell lymphoma prognosis / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the association of micoRNA-related genes DROSHA single nucleotide polymorphisms (SNP) rs10719 and rs6877842, DICER1 rs3742330and GEMIN4 rs3744741 with prognosis of T-cell lymphoma.</p><p><b>METHODS</b>Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to determine the genotypes of the above 4SNPs and their associations with complete remission (CR) rate and overall survival (OS) in 163 patients with TCL.</p><p><b>RESULTS</b>Patients carrying the rs6877842 CG genotype had a significantly higher CR rate compared with those carrying the CC genotype (OR=0.07, 95% CI 0.01-0.72, P=0.026); the same for patients carrying the DICER1 rs3742330 GG genotype compared with those carrying the GA genotype (OR=0.15, 95% CI 0.02-0.97, P=0.047) or the AA genotype (OR=0.11, 95% CI 0.02-0.71, P=0.020). In addition, patients with the DICER1 rs3742330 GG genotype had a significantly improved OS compared with those carrying the GA (HR=9.02, 95% CI 1.22-66.92, P=0.031) or AA genotype (HR=8.77, 95% CI 1.19-64.67, P=0.033). The other two SNPs of rs10719 and rs3744741 had no significant association with CR or OS.</p><p><b>CONCLUSION</b>DROSHA rs6877842 and DICER1 rs3742330 were independent factors for TCL CR, and DICER1 rs3742330 was also an independent prognostic factor for TCL OS.</p>

Advance on Dicer gene and its role in female reproduction / 中华医学遗传学杂志

Dicer is an RNAse III endonuclease that is essential for the biogenesis of microRNAs and small interfering RNAs. These small RNAs transcriptionally and post-transcriptionally regulate mRNA expression through RNA interference mechanisms. Recently, the function of Dicer in female reproduction has begun to be elucidated through the use of knockout mouse models. Several latest studies have indicated that Dicer gene plays a key role in female reproductive processes such as oocyte maturation, early embryonic development and implantation and steroidgenesis. When Dicer expression is decreased in female reproductive tissues or cells, it will cause infertility. In this article, author discuss the role of Dicer gene in female reproductive tract, and advance of Dicer gene study in female reproductive events.

Nucleotide bias of DCL and AGO in plant anti-virus gene silencing

Plant Dicer-like (DCL) and Argonaute (AGO) are the key enzymes involved in anti-virus post-transcriptional gene silencing (AV-PTGS). Here we show that AV-PTGS exhibited nucleotide preference by calculating a relative AV-PTGS efficiency on processing viral RNA substrates. In comparison with genome sequences of dicot-infecting Turnip mosaic virus (TuMV) and monocot-infecting Cocksfoot streak virus (CSV), viral-derived small interfering RNAs (vsiRNAs) displayed positive correlations between AV-PTGS efficiency and G+C content (GC%). Further investigations on nucleotide contents revealed that the vsiRNA populations had G-biases. This finding was further supported by our analyses of previously reported vsiRNA populations in diverse plant-virus associations, and AGO associated Arabidopsis endogenous siRNA populations, indicating that plant AGOs operated with G-preference. We further propose a hypothesis that AV-PTGS imposes selection pressure(s) on the evolution of plant viruses. This hypothesis was supported when potyvirus genomes were analysed for evidence of GC elimination, suggesting that plant virus evolution to have low GC% genomes would have a unique function, which is to reduce the host AV-PTGS attack during infections.

The effect of silencing Dicer by small interference RNA on the biological characteristics of human glioma cells / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the effect of silencing Dicer by small interference RNA (siRNA) to suppress the global microRNA (miRNAs) expression on the biological characteristics of TJ905 glioblastoma cells.</p><p><b>METHODS</b>The silencing effect of RNA interference on Dicer expression was evaluated by reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis and immunofluorescence staining. The cell proliferation rate and cell cycle kinetics were detected by MTT assay and flow cytometry respectively, and the cell invasive ability was evaluated by transwell assay.</p><p><b>RESULTS</b>The siRNA targeting Dicer suppressed the expression of Dicer in TJ905 cells. Meanwhile, the proliferation activity and invasive ability were significantly enhanced in cells transfected with Dicer siRNA compared to those cells transfected with scrambled siRNA and the control cells.</p><p><b>CONCLUSION</b>Suppression of Dicer expression renders the glioma cells harboring more aggressive phenotype. This preliminary finding suggests that global lower expression of miRNAs may play an oncogenic role.</p>

Dicer efficiently converts large dsRNAs into siRNAs suitable for COX-2 gene / 中南大学学报(医学版)

OBJECTIVE@#To report the use of Dicer to cleave double-stranded RNA (dsRNAs) into small interference RNAs (D-siRNAs) that can target multiple sites within an mRNA, and to acquire an new method to cure inflammation of the airway and tumor.@*METHODS@#Using RiboMAX Large Scale RNA Production Systems-SP6 and T7 kit were used to transcribe A549 cell COX-2 DNA into RNA (dsRNAs). We mixed dsRNAs with Dicer in the reaction buffer. We recovered siRNAs using RNA Purification Column.@*RESULTS@#Dicer efficiently converted double-stranded RNA of COX-2 into small interference RNAs of 21 approximately 23 bp.@*CONCLUSION@#Dicer efficiently converts double-stranded RNA (dsRNA) into small interference RNAs (D-siRNAs of 21 approximately 23 bp).

Decreased expression of DICER1 in gastric cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The role of epigenetics in gene expression regulation and development significantly enhances our understanding of carcinogenesis. All the tumor related genes may be the target of epigenetical or genetic regulation. We selected some epigenetically regulated genes for cDNA array analysis and observed variability in the expression of the DICER1 gene in distinct stages of gastric cancer. The aim of this study was to assess the correlation between the expression of DICER1, an epigenetically regulated gene, and gastric cancer.</p><p><b>METHODS</b>To detect the expression of 506 tumor-associated genes, including DICER1, in the matched cancerous mucosa, pre-malignant lesion (adjacent mucosa), non-cancerous gastric mucosa and distant lymphocyte metastatic lesion in 3 cases of gastric cancers using cDNA array. DICER1 mRNA expression and DICER1 protein expression were further analyzed by Real-time PCR and Western blot in 32 cases of progressive gastric cancer. DICER1 protein expression was also detected in 33 early and 30 progressive gastric cancers by the immunohistochemistry (IHC) method.</p><p><b>RESULTS</b>In 3 cases of gastric cancer cDNA array showed dramatically decreased expression of DICER1 in pre-malignant lesion, cancerous mucosa and distant lymphocyte metastatic lesions compared with matched noncancerous gastric mucosa, pre-malignant lesion and cancerous mucosa. Real-time PCR results showed that the expression level of DICER1 mRNA in gastric cancer was significantly down-regulated compared to normal gastric tissue (P < 0.05). The IHC assay also showed that the expression of DICER1 was significantly decreased in progressive gastric cancer. Among the 63 cases of gastric cancers, 13/33 early (39.4%) and 19/30 (63.3%) progressive cancers showed negative expression of DICER1 (50.8%). The difference in expression of DICER1 between early and progressive gastric cancers was significant (P < 0.01). The result of Western blotting showed that DICER1 protein was down-regulated significantly in advanced gastric cancer (P < 0.05).</p><p><b>CONCLUSIONS</b>DICER1 expression is decreased during the progression of gastric cancer, especially in progressive gastric cancers, which indicating DICER1 may play an important role in the development of cancer and the epigenetical regulation involved.</p>

RNase III-prepared short interfering RNAs induce degradation of SARS-coronavirus mRNAs in human cells / 生物工程学报

SARS-associated coronavirus has been identified for the cause of Severe Acute Respiratory Syndrome, for which there is no efficacious drugs or vaccines. RNA interference (RNAi) is a process in cell to degradation specific target mRNA by double-stranded RNA. In mammalian cells, RNAi can be triggered by short interfering RNA (siRNA). RNA interference of virus-specific genes has emerged as a potential antiviral mechanism. This work evaluated if RNase III-prepared short interfering RNAs can induce specific degradation of SARS-coronavirus mRNAs in human cells. Three of SARS genes, RNA dependent RNA polymerase (RdRp), spike and nucleocapsid, were amplified with T7 promoter-flanked primers. Long length double-stranded RNA of these genes were transcribed in vitro and then were cleaved to <30bp length short interfering RNA with E. coli RNase III. These siRNAs were termed esiRNA-R, esiRNA-S and esiRNA-N respectively. RdRp, spike and nucleocapsid DNA fragments were inserted into the plasmid pGL3-Control, obtained plasmids pGL-R, pGL-S and pGL-N can express hybrid mRNAs luciferase-RdRp, spike and -nucleocapsid in cells. Above plasmids and esiRNAs were co-transfected to HEK293F cells with reference plasmid pRL-TK. Firefly luciferase and Renilla luciferase activity were measured. Hybrid mRNAs' abundance was measured using reverse transcription real-time PCR. Firefly luciferase expression of pGL-R was reduced to 13% by esiRNA-R. Expression of pGLS was reduced to 11% by esiRNA-S. Expression of pGL-N was reduced to 40% by esiRNA-N. Control esiRNAs didn't affect luciferase expression; Hybrid mRNAs' abundance was dramatically reduced by corresponding esiRNAs. RNase III-prepared short interfering RNAs induce robust and specific degradation of SARS-coronavirus mRNAs in HEK293F cells. These siRNAs could be used to inhibit SARS-coronavirus in future research.

The multifaceted roles of the RNA processing enzyme ribonuclease III.

Ribonuclease III was initially characterized as an endoribonuclease specific for double stranded RNA. Subsequently RNase III was found to be involved in the processing and maturation of ribosomal and tRNAs. Recent studies demonstrate that RNase III also participates in the processing of small stable RNAs. A number of other biological processes in which RNase III participates are: (a), conversion of polycistronic transcript of the bacteriophage T7 early region into discrete monocistronic mRNAs, (b), controlling expression of a variety of genes by processing of gene transcripts, (c), autoregulation of its own gene and (d), regulation of mRNA stability and stimulation of translation. No single processing enzyme displays such a wide variety of roles in RNA metabolism and gene expression as RNA processing enzyme ribonuclease III. This review provides an account of the various roles of RNase III in regulating gene expression and RNA metabolism.