Expression Levels Of miR-106b Research Articles

Comparison of miR-106b, miR-191, and miR-30d expression dynamics in milk with regard to its composition in Holstein and Ayrshire cows.

Milk composition varies considerably and depends on paratypical, genetic, and epigenetic factors. MiRNAs belong to the class of small non-coding RNAs; they are one of the key tools of epigenetic control because of their ability to regulate gene expression at the post-transcriptional level. We compared the relative expression levels of miR-106b, miR-191, and miR-30d in milk to demonstrate the relationship between the content of these miRNAs with protein and fat components of milk in Holstein and Ayrshire cattle. Milk fat, protein, and casein contents were determined in the obtained samples, as well as the content of the main fatty acids (g/100 g milk), including: saturated acids, such as myristic (C14:0), palmitic (C16:0), and stearic (C18:0) acids; monounsaturated acids, including oleic (C18:1) acid; as well as long-, medium- and short-chain, polyunsaturated, and trans fatty acids. Real-time stem-loop one-tube reverse transcription polymerase chain reaction with TaqMan probes was used to measure the miRNA expression levels. The miRNA expression levels in milk samples were found to be decreased in the first two months in Holstein breed, and in the first four months in Ayrshire breed. Correlation analysis did not reveal any dependence between changes in the expression level of miRNA and milk fat content, but showed a multidirectional relationship with individual milk fatty acids. Positive associations between the expression levels of miR-106b and miR-30d and protein and casein content were found in the Ayrshire breed. Receiver operating characteristic curve analysis showed that miR-106b and miR-30d expression levels can cause changes in fatty acid and protein composition of milk in Ayrshire cows, whereas miR-106b expression level determines the fatty acid composition in Holsteins. The data obtained in this study showed that miR-106b, miR-191, and miR-30d expression levels in milk samples have peculiarities associated with breed affiliation and the lactation period.

MiR-106b-25 Promotes Chemoresistance in Acute Myeloid Leukemia Via Abolishing Multiple Apoptotic Pathways

Introduction: Chemoresistance and disease relapse remain the main obstacles responsible for treatment failure in leukemia. MicroRNAs (miRNAs) play essential roles in various physiological and pathological processes, including cell proliferation, differentiation, metabolism, and cancer development. The miR-106b-25 cluster consists of three miRNAs: miR-106b, miR-93 and miR-25. We have previously reported that miR-106b-25 was associated with chemoresistance by negatively regulated EP300 in breast cancer, but its role in hematological malignancies has not yet been elucidated. Here, we aim to clarify the biological role and underlying mechanisms of miR-106b-25 on drug resistance in leukemia.Methods: To see whether the miR-106b-25 was associated with the poor prognosis of AML patients, enriched LSCs (CD34 + cells) were isolated from the bone marrow of 18 newly diagnosed AML patients, the expression of miR-106b, miR-93, and miR-25 were examined, respectively. The expression levels of miR-106b, miR-93 and miR-25 were further determined in the doxorubicin-resistant leukemia cell line K562/A02 and HL60/ADR, compared with their parental cell lines. In addition, K562 cells were transduced with lentiviral vectors carrying miR-106b-25, and cell proliferation, drug resistance, colony-forming assay, apoptosis assays were performed to explore the function of miR-106b-25 overexpression in leukemia cells in vitro. To investigate the role of miR-106b-25 on tumor growth and overall survival after drug treatment, we performed xenotransplantation in nude mice using miR-106b-25 overexpressed K562 cells. To further clarify the function of each microRNA function in this cluster, K562 cells were also transduced with lentiviral vectors carrying individual miR-25, miR-93, or miR-106b separately. Cell proliferation, colony forming assay and cell apoptosis assay were also carried out subsequently. Simultaneously, RNA-sequencing was performed to reveal the underlying mechanisms of miR-106b-25 in the chemoresistance of myeloid leukemia. To experimentally confirm the direct target of the miR-106b-25 cluster in AMLs, we further performed a dual-luciferase reporter assay.Results: Upregulated miR-106b, miR-93 and miR-25 expression in enriched LSCs were significantly associated with shortened overall survival of AML patients. We also found miR-106b, miR-93 and miR-25 were significantly upregulated in drug-resistant leukemia cell lines compared with its parental cell lines. Overexpression of miR-106b-25 cluster promoted cell proliferation, led to resistance of K562 cells to doxorubicin, imatinib and ABT-737 (BCL-2 inhibitor) in liquid culture and drug-resistant colony-forming assays. Overexpression of miR-93 or miR-106b accelerated cell growth, and all the three miRNAs can promote drug-resistant colony-forming and inhibit cell apoptosis. RNA-sequencing (RNA-Seq) data revealed that multiple critical genes related to apoptotic pathways were downregulated after overexpressing miR-25, miR-93, miR-106b as well as the whole cluster, such as TP73, BAX, BAK1, Caspase-7, CDKN1A and BTG2. RT-qPCR confirmed that these genes are reduced with or without ABT-737 treatment. Luciferase assay further identified TP73 was a direct target of miR-93 and miR106b, BAK1 was a direct target of miR-25, and CASPASE-7 was a direct target of all these three miRNAs.Conclusions: In summary, we made the novel observation that miR-106-25 is associated with AML drug-resisitance and disease prognosis and identified TP73, BAK1 caspase-7 as a novel direct target of this cluster. Further studies revealed that the biological effects of miR-106b-25 cluster on leukemic cell proliferation, chemoresistance and apoptosis were mediated through regulation of apoptotic pathway. These findings indicate a promising diagnostic biomarker and a potential target therapeutic strategy for AML patients. DisclosuresNo relevant conflicts of interest to declare.

Circulating miRNAs as Potential Biomarkers in Prostate Cancer Patients Undergoing Radiotherapy

IntroductionDisease recurrence is a major concern in patients with localized prostate cancer (PCa) following treatment with radiotherapy (RT), and few studies have evaluated the clinical relevance of microRNAs (miRNAs) prior and post-RT.PurposeWe aimed to investigate the significance of miRNAs in the outcomes of prostate cancer patients undergoing radiotherapy and to identify the related pathways through bioinformatics analysis.Materials and MethodsThe expression levels of miR-21, miR-106b, miR-141 and miR-375 involved in the response to radiotherapy were assessed by RT-qPCR in the serum of PCa patients (n=56) prior- and post-RT.ResultsLow expression levels of miR-106b prior-RT were associated with extracapsular extension and seminal vesicles invasion by the tumor (p=0.031 and 0.044, respectively). In the high-risk subgroup (n=47), post-RT expression levels of miR-21 were higher in patients with biochemical relapse (BR) compared to non-relapse (p=0.043). Also, in the salvage treatment subgroup (post-operative BR; n=20), post-RT expression levels of miR-21 and miR-106b were higher in patients with BR compared to non-relapse (p=0.043 and p=0.032, respectively). In the whole group of patients, high expression levels of miR-21 prior-RT and of miR-106b post-RT were associated with significantly shorter overall survival (OS; p=0.049 and p=0.050, respectively). No associations were observed among miR-141 and miR-375 expression levels with clinicopathological features or treatment outcome. Bioinformatics analysis revealed significant enrichment in DNA damage response pathways.ConclusionCirculating miRNAs prior or post-RT may hold prognostic implications in patients with PCa.

Upregulation of miR-21 and miR-106b in plasma and tissues as a possible prognostic marker in aggressive breast cancer

Background: The miRNAs are referred to small non-coding RNAs (consisting of 18 to 25 nucleotides). Functional studies have shown their functions to be oncogenes or tumor suppressor genes in different types of cancers. The miR-106b and miR-21 have been identified to participate in the biological behaviors of cells. This study aimed to evaluate the tissue and plasma levels of miR-21 and miR-106b in patients with breast cancer who were diagnosed with ductal carcinoma. Methods: In total, 40 cases of breast cancer patients 180 samples were examined in this project. Samples included ductal carcinoma breast tumors (n=40), normal breast tissues of the margin of the tumor (n=40) and 20 samples from unaffected mammary tissue of females undergoing reduction mammoplasty (control group), plasma samples of patients with breast cancer (n=40), and plasma of non-affected individuals (n=40). The expression levels of miR-106b and miR-21 were determined using SYBR Green real-time RT-PCR assay in breast tissues and plasma of cancerous patients in comparison to the controls. Results: MiR-106b and miR-21 revealed much higher expression in tissues and plasma of patients with breast cancer in comparison to that in the group of control (P<0.001). High levels of mir-106b and miR-21 expression in plasma and tumor tissues were highly correlated with tumors in higher stages and lymph node involvement (P<0.0001). Conclusions: Based on the obtained results, upregulation of miR-106b and miR-21 in the plasma of patients with breast cancer can act as a possible non-invasive biomarker for breast cancer prognosis. Further follow-up studies are required to confirm this.

Study of the Effect of Linoleic Acid on the Expression Level of MicroRNA-106b and MicroRNA-20a and their Related Target MHC Class I Chain-related Protein A in Docetaxel-treated Gastric Cancer Cells

Background: MicroRNAs are involved in response to therapeutic agents and have the ability to regulate the expression level of the targets associated with cancer growth and progression. As a dangerous signal in tumor cells, increased expression level of MHC class I chain-related protein A (MICA) could activate the immune system and induce responses to tumor cells. We conducted the present research to study the effect of linoleic acid (LA) and docetaxel alone or in combination with miR-106b, miR-20a, and MICA expression level in metastatic gastric cancer (GC) cell line MKN-45. Method: The study was an in vitro study using the gastric cancer cell line MKN- 45, which was cultured and treated with docetaxel and LA. Subsequently, the expression level of miR-106b, miR-20a, and MICA were assessed with quantitative real-time polymerase chain reaction. Results: MiR-106b decreased in LA and LA/docetaxel (P < 0.0001 and P = 0.002),and increased in docetaxel alone (P = 0.01). Meanwhile, miR-20a significantly decreased in docetaxel and LA/docetaxel (P < 0.0001), increased in LA treatment (P = 0.02). Regarding MICA, it significantly decreased in all the treated cells (P < 0.0001, p <0.0001, and P=0.0002 for docetaxel, LA and docetaxel/LA, respectively) but with different reduction intensities. Conclusion: Using LA or docetaxel alone had a different effect on miR-106b, miR-20a, and MICA expression level, yet in a simultaneous treatment, their positive effects were intensified. LA enhanced the effect of docetaxel concerning the expression level of miR-106b, miR-20a, and MICA and vice versa, which suggested that LA could be employed as an effective complementary agent in GC along with docetaxel.

Study on the mechanism of inhibiting invasion of human laryngeal squamous cell carcinoma Hep-2 and TU212 cells after the downregulation of miRNA-106b

Objective To investigate the effect of miRNA-106b (miR-106b) on human laryngeal squamous cell carcinoma Hep-2 and TU212 cells and its mechanism. Methods Hep-2 and TU212 cells were divided into miR-106b inhibitory sequence transfected group (the experimental group), miR-106b competitive negative sequence transfected group (the negative control group) and non-intervention group (the blank group). The inhibitory effect of miR-106b inhibitory sequence on the expression of miR-106b was verified by using reverse transcription quantitative polymerase chain reaction (qRT-PCR). Whether phosphatase and tensin homolog (PTEN) was the target gene of miR-106b was analyzed by using bioinformatics and luciferase report vector. PTEN small interfering RNA (siRNA) was used to inhibit the expression of PTEN in Hep-2 and TU212 cells. Transwell method and Western blot were used to detect the change of invasion ability of Hep-2 and TU212 cells after miR-106b silencing or the PTEN intervening, and the expression change of PTEN, epithelial cadherin and vimentin. Results The relative expression levels of miR-106b in Hep-2 and TU212 cells in the experimental group were 0.110 ± 0.037 and 0.074 ± 0.009, respectively, which were lower than those in the negative control group (1.013±0.059 and 1.035±0.062, respectively; all P < 0.05). In Transwell experiments, the number of invasive cells in each field of Hep-2 and TU212 cells in the experimental group was less than that in the negative control group [(37.09±4.02) vs. (95.65±4.77), (29.16±2.49) vs. (103.19±6.08), all P < 0.05]. The bioinformatics analysis results showed that 3'-UTR region of PTEN mRNA was complementary to 3'-UTR region of miR-106b. Dual-luciferase reporter system analysis showed that the luciferase reporter activity of wild-type PTEN gene transfected with miR-106b was decreased to (22.84±2.68)%, and that of mutant PTEN gene transfected with miR-106b was almost unchanged [(92.08±3.44)%], and the difference was statistically significant (P < 0.001). The expression level of PTEN protein of Hep-2 and TU212 cells in the experimental group was higher than that in the negative control group. Transwell method showed that the number of invasive cells in each field of Hep-2 and TU212 cells in the experimental group with the inhibition of PTEN expression was more than that in the experimental group without the inhibition of PTEN expression [(65.08±3.57) vs. (26.72±2.58), (57.38±4.96) vs. (31.81±2.97), all P < 0.05]. Western blot showed that the expression level of epithelial-cadherin was up-regulated and vimentin was down-regulated of Hep-2 and TU212 cells in the experimental group with the inhibition of PTEN expression. Conclusions The human laryngeal squamous cell carcinoma Hep-2 and TU212 cell miR-106b can influence the downstream invasion-related protein of PTEN and change the cell invasion ability through the targeted regulation of PTEN expression. Key words: Laryngeal neoplasms; Carcinoma, squamous cell; Neoplasm invasiveness; RNA interference; miRNA-106b; Phosphatase and tensin homolog

Associations of high expression of miR-106b-5p detected from FFPE sample with poor prognosis of RCC patients

ObjectiveThe present study aims to determine the association of microRNA-106b-5p (miR-106b-5p) expression with the clinicopathological features and prognosis of renal cell carcinoma (RCC). Patents and methodsThe formalin-fixed paraffin-embedded(FFPE) Tumor tissues were collected from 284 RCC patients. The expression of miR-106b-5p was examined by Reverse Transcription Real-time Quantitative Polymerase Chain Reaction (RT-qPCR), followed by correlation analysis with clinicopathological features and prognosis. Patient survival analysis was determined by the Kaplan-Meier method using the log-rank test was used for patient survival analysis, and the univariate and multivariate analysis was determined by a Cox’s regression model. ResultsKaplan-Meier analysis indicated that patients with high miR-106b-5p expression showed a significantly shorter overall survival, compared with patients with low miR-106b-5p expression (p = 0.001). Univariate and multivariate analysis considered miR-106b-5p expression as an independent risk factor for predicting the prognosis of RCC patients. No significant evident showed that the expression level of miR-106b was related to gender, age, tumor size or tumor stage. Also, the results above were verified by analyzing the data of 506 cases from The Cancer Genome Atlas database (TCGA). ConclusionsThe results pointed out that the high expression of miR-106b-5p serves as an independent factor for predicting the worse prognosis of RCC patients.

MiR-106b promotes migration and invasion through enhancing EMT via downregulation of Smad 7 in Kazakh's esophageal squamous cell carcinoma.

Accumulated evidence suggests that miR-106b played a key role in the promotion of the metastases of cancer; however, little is known about miR-106b in esophageal squamous cell carcinoma (ESCC). To investigate expression level of miR-106b in ESCC tissues, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-106b expression in 35 Kazakh's ESCC and paired normal adjacent tissues (NATs). To evaluate the role mediated by miR-106b in the proliferation, migration, and invasion, MTT, wound healing, and transwell assays were employed, respectively. Luciferase reporter assay was used to identify the downstream target through miR-106b. To understand the regulation between miR-106b and Smad 7, qRT-PCR and western blot were performed. The present study showed that miR-106b was pronouncedly upregulated in ESCC relative to paired NAT and that upregulated miR-106b was significantly associated with lymph node metastases. MiR-106b was found to be able to promote proliferation, migration, and invasion of ESCC cells in vitro. Smad 7 was confirmed as a downstream target of miR-106b in our experimental setting. Smad 7 was remarkably downregulated in ESCC compared with paired NAT. In addition, upregulation of miR-106b can promote epithelial mesenchymal transition (EMT) in ESCC cell in vitro. Our results indicated that miR-106b can promote migration and invasion of ESCC cells through enhancing EMT process via downregulation of Smad 7, suggesting that miR-106b can be a potential molecular phenotype in ESCC metastases.

MicroRNA‐106b targets FUT6 to promote cell migration, invasion, and proliferation in human breast cancer

It is demonstrated that the maladjustment of microRNA (miRNA) plays significant roles in the occurrence and development of tumors. MicroRNA-106b-5p (miR-106b), a carcinogenic miRNA, is identified as a dysregulated miRNA in human breast cancer. In this article, the expression levels of miR-106b were discovered to be particularly higher in breast cancer tissues than that in the corresponding adjacent tissues. Accordingly, miR-106b was higher expressed in the breast cancer cell lines compared with that in the normal breast cell lines. Moreover, according to the data previously reported, increased expression of miR-106b was significantly associated with advanced clinical stages and poor prognosis in breast cancer. Fucosyltransferase 6 (FUT6), a member of the fucosyltransferase (FUT) family, was found to have a reduced expression in tissues or cells with higher level of miR-106b in breast cancer. Additionally, down-regulation of miR-106b increased the expression of FUT6 and resulted in an obvious decrease of cell migration, invasion, and proliferation in MDA-MB-231 cells. Furthermore, over-expressed FUT6 reversed the impacts of up-regulated miR-106b on cell migration, invasion, and proliferation in MCF-7 cells, indicating that FUT6 might be directly targeted by miR-106b and serve as therapeutic targets for breast cancer. In brief, our results strongly showed that the low expression of FUT6 regulated by miR-106b contributed to cell migration, invasion, and proliferation in human breast cancer. © 2016 IUBMB Life, 68(9):764-775, 2016.

MiR-106b inhibits tau phosphorylation at Tyr18 by targeting Fyn in a model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by β-amyloid deposits and neurofibrillary tangles consisting of hyperphosphorylated tau protein. Increasing evidence has revealed that microRNAs (miRNAs) are implicated in the pathogenesis of AD. However, the effect of miRNAs on abnormal tau phosphorylation remains largely unclear so far. In this study, we investigated the role of miR-106b in tau phosphorylation and identified a new molecular mechanism of the hyperphosphorylation of tau. The results of qRT-PCR showed that the expression level of miR-106b was decreased, but Fyn was increased in the temporal cortex of AD patients. Overexpression of miR-106b inhibited Aβ1-42-induced tau phosphorylation at Tyr18 in SH-SY5Y cells stably expressing tau (SH-SY5Y/tau), whereas no changes were observed in tau phosphorylation at Ser396/404. Dual-luciferase reporter gene assay validated that Fyn was a direct target gene of miR-106b. In addition, western blot analysis revealed that Fyn protein expression was suppressed when SH-SY5Y cells were transfected with miR-106b mimics. Endogenous Fyn expression was knockdown by transfection with a small interfering RNA specific for Fyn (si-Fyn). The phosphorylation level of tau at Tyr 18 was decreased in the si-Fyn group compared with the negative control group, but the inhibitory effect of si-Fyn on tau phosphorylation was attenuated when miR-106b expression was inhibited. Taken together, these data suggest that miR-106b inhibits Aβ1-42-induced tau phosphorylation at Tyr18 by targeting Fyn. Our findings extend the knowledge about the regulation of tau phosphorylation and the regulatory mechanism of Fyn gene expression.

MicroRNA-106b promotes pituitary tumor cell proliferation and invasion through PI3K/AKT signaling pathway by targeting PTEN.

The purpose of this study was to investigate the expression of microRNA-106b (miR-106b) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in pituitary tumor and to confirm whether miR-106b promotes proliferation and invasion of pituitary tumor cells through the PI3K/AKT signaling pathway by targeted regulation of PTEN expression, and thereby to find new targets for the treatment of pituitary tumor. Fifty-five cases of pituitary tumor tissue samples were collected, including 29 cases of invasive pituitary tumor, non-invasive 26 cases, and 8 normal pituitaries. The expression level of miR-106b in pituitary tumor tissue was detected by quantitative real-time PCR, and the expression of PTEN protein was detected by immunohistochemistry. PTEN 3'-untranslated region (UTR) luciferase vector was constructed, and dual-luciferase reporter gene assay was employed to examine the effect of miR-106b on PTEN 3'-UTR luciferase activity. AtT-20 cells were transfected with miR-106b mimics, miR-106b inhibitor, PTEN expression plasmid, and miR-106b mimics + PTEN expression plasmid respectively, and the changes in cellular proliferation and invasion were observed via MTT method and transwell assay respectively. PTEN messenger RNA (mRNA) expression was determined by quantitative real-time PCR, and western blotting was performed to detect the expression of PTEN, PI3K, AKT, and pAKT. miR-106b showed up-regulation in invasive pituitary tumor tissue: the expression level was significantly up-regulated compared with normal tissues and the non-invasive pituitary tumor tissue (P<0.05). The positive rate of PTEN protein expression in invasive pituitary tumor tissues was significantly lower than in normal and non-invasive tissues (P<0.01). Dual-luciferase reporter gene assay showed that miR-106b could bind to the 3'-UTR of PTEN specifically and significantly inhibited the luciferase activity, cutting the 46% (P<0.01). Down-regulation of miR-106b or up-regulation of PTEN could suppress cell proliferation and invasion of AtT-20 cells, and PTEN expression plasmid could partially simulate the function of miR-106b. Expression of PTEN mRNA and protein decreased significantly in AtT-20 cells overexpressing miR-106b. The expression levels of PI3K and p-AKT were significantly inhibited by miR-106b inhibitor and increased by miR-106b mimics. The expression of miR-106b showed up-regulation in pituitary tumor tissues, while the protein expression of PTEN presented opposite results. The findings of this study further demonstrated that miR-106b as an oncogene regulated the pituitary tumor cell proliferation and invasion in vitro by directly targeting PTEN through the PI3K/AKT signaling pathway. Our study suggests that miR-106b and PTEN are likely to serve as potential diagnostic biomarkers or therapeutic targets for pituitary tumor treatment in the future.

MiR-106b promotes cancer progression in hepatitis B virus-associated hepatocellular carcinoma.

To investigate the effect of miR-106b on tumor progression in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC). A total of 120 patients who underwent liver resection for HCC at National Cheng Kung University Hospital were enrolled in the present study. MicroRNA (miRNA) array was first used to screen the miRNA expression profiles in HCC patients. The clinical records were retrospectively analyzed, and correlations with the miRNA expression profiles were evaluated. The mRNA expression levels of the miR-106b-25 cluster (miR-106b, miR-93 and miR-25), and MCM7 in tumor and non-tumor samples were quantitated using quantitative real-time reverse transcription-polymerase chain reaction (q-RT-PCR) analysis, and correlations in the levels of miR-106b, miR-93 and miR-25 expression were calculated. Kaplan-Meier overall and disease-free survival rates of HBV-associated HCC patients were analyzed using the log-rank test based on miR-106b expression. The comparison of the miR-106b expression levels in patients with different clinical outcomes was analyzed using Mann-Whitney U tests. Furthermore, a hepatitis B virus X protein (HBx) expression plasmid was transfected into Huh7 and Hep 3B cells. The expression levels of the miR-106b-25 cluster and MCM7 in HBx-expressing Huh7 and Hep 3B cells were detected using q-RT-PCR. miRNA array screening showed that miR-106b and its cluster, miR-93 and miR-25 were up-regulated in HCC patients (P < 0.01). The value of miR-106b expression in HBV-associated HCC patients was significantly higher than that in HCV- (P < 0.05) or non-B/non-C- (P < 0.001) associated HCC patients. The expression of the miR-106b-25 cluster was significantly higher in tumor tissue (P < 0.001) and associated with the host gene, MCM7, in clinical specimens from HBV-associated HCC patients. Furthermore, the expression levels of miR-106b, miR-93 and miR-25 were positively correlated in HBV-associated HCC tissues (miR-106 vs miR-93, r = 0.75; miR-93 vs miR-25, r = 0.69; miR-106b vs miR-25, r = 0.33). The overall and disease-free survival curves showed that high-miR-106b expression was correlated with the poor prognosis of HBV-associated HCC. HCC differentiation was significantly correlated with miR-106b expression (P < 0.05). Lower miR-106b expression levels resulted in the well differentiation of HCC. Moreover, the expression of the miR106b-25 cluster and MCM7 was up-regulated in Huh7 and Hep 3B cells after transfection with the HBx expression plasmid. The data obtained in the present study suggests that HBx enhances miR-106b transcription to promote tumor progression in HBV-associated HCC.

Repetitive magnetic stimulation promotes neural stem cells proliferation by upregulating MiR-106b in vitro.

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.

Prognostic value of miR-106b expression in breast cancer patients

BackgroundThe aim of the present study was to evaluate whether the level of expression of tissue or plasma miR-106b can be used to predict clinical outcomes in breast cancer patients. MethodsBoth tissue and plasma samples were collected and analyzed from 173 patients with primary breast cancer and a set of 50 women with fibroadenoma. The relative expression levels of miR-106b were determined using real-time quantitative reverse transcription polymerase chain reaction and in situ hybridization. ResultsThe levels of miR-106b were upregulated in both tissue and plasma samples from breast cancer patients. The expression levels showed a linear correlation (rs = 0.748, P < 0.001) and were significantly correlated with tumor size, Ki67 expression, and lymph node metastasis (all P < 0.05). Patients with high miR-106b expression levels tended to have shorter disease-free survival times and overall survival times (P < 0.001). In a Cox regression model, high-level tissue and plasma miR-106b expression were unfavorable prognostic factors, and receiver-operating characteristic analysis revealed that the tissue and plasma miR-106b levels provided considerable diagnostic accuracy, yielding an area under the ROC curve of 0.785 and 0.856, respectively. ConclusionsMiR-106b was found to be associated with a high risk of recurrence of breast cancer, and miR-106b is a putative plasma marker for risk assessment in patients with breast cancer.

Upregulation of microRNA-106b is associated with poor prognosis in hepatocellular carcinoma.

BackgroundMicroRNA-106b (miR-106b) is a member of the miR-106b ~ 25 cluster. It has been reported that miR-106b acts as an oncogene and is upregulated in many human cancers. However, the prognostic value of miR-106b in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to investigate the clinical significance of miR-106b expression in HCC.MethodsWe determined the expression level of miR-106b in 104 cases of paired HCC and adjacent non-tumor tissues by quantitative real-time PCR (qRT-PCR). The correlation between miR-106b expression and prognosis of HCC was studied by univariate and multivariate analysis. Multivariate analysis of the prognostic factors was performed with Cox proportional hazards model.ResultsMiR-106b expression was significantly upregulated in as high as 76.0% of HCC tissues, compared with their non-tumor counterparts (P < 0.001). High miR-106b expression was significantly associated with large tumor size (P = 0.019) and vascular invasion (P = 0.016). Kaplan-Meier analysis showed that patients with high miR-106b expression had a worse overall survival than patients with low miR-106b expression (log-rank P = 0.004). The multivariate Cox regression analysis indicated that miR-106b expression was an independent prognostic factor for overall survival (HR, 2.002; 95% CI, 1.130-6.977; P = 0.027).ConclusionOur data indicated that miR-106b expression was significantly upregulated in HCC and could serve as a potential unfavorable prognostic biomarker.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_226

MicroRNA-106b in cancer-associated fibroblasts from gastric cancer promotes cell migration and invasion by targeting PTEN.

It is well established that the interaction between cancer cells and microenvironment has a critical role in tumor development, but the roles of miRNAs in this interaction are rarely known. Here, we have shown that miR-106b is up-regulated in cancer associated fibroblasts compared with normal fibroblasts established from patients with gastric cancer, the expression level of miR-106b is associated with poor prognosis of patients, and CAFs with down-regulated miR-106b could significantly inhibit gastric cancer cell migration and invasion by targeting PTEN. Taken together, these data suggest that miR-106b might be a novel candidate target for the treatment of gastric cancer.

Signature of Circulating MicroRNAs as Potential Biomarkers in Vulnerable Coronary Artery Disease

AimsMicroRNAs (miRNAs) play important roles in the pathogenesis of cardiovascular diseases. Circulating miRNAs were recently identified as biomarkers for various physiological and pathological conditions. In this study, we aimed to identify the circulating miRNA fingerprint of vulnerable coronary artery disease (CAD) and explore its potential as a novel biomarker for this disease.Methods and ResultsThe Taqman low-density miRNA array and coexpression network analyses were used to identify distinct miRNA expression profiles in the plasma of patients with typical unstable angina (UA) and angiographically documented CAD (UA group, n = 13) compared to individuals with non-cardiac chest pain (control group, n = 13). Significantly elevated expression levels of miR-106b/25 cluster, miR-17/92a cluster, miR-21/590-5p family, miR-126*, and miR-451 were observed in UA patients compared to controls. These findings were validated by real-time PCR in another 45 UA patients, 31 stable angina patients, and 37 controls. In addition, miR-106b, miR-25, miR-92a, miR-21, miR-590-5p, miR-126* and miR-451 were upregulated in microparticles (MPs) isolated from the plasma of UA patients (n = 5) compared to controls (n = 5). Using flow cytometry and immunolabeling, we further found that Annexin V+ MPs were increased in the plasma samples of UA patients compared to controls, and the majority of the increased MPs in plasma were shown to be Annexin V+ CD31+ MPs. The findings suggest that Annexin V+ CD31+ MPs may contribute to the elevated expression of the selected miRNAs in the circulation of patients with vulnerable CAD.ConclusionThe circulating miRNA signature, consisting of the miR-106b/25 cluster, miR-17/92a cluster, miR-21/590-5p family, miR-126* and miR-451, may be used as a novel biomarker for vulnerable CAD.Trial RegistrationChinese Clinical Trial Register, ChiCTR-OCH-12002349.

Identification of miR-106b-93 as a negative regulator of brown adipocyte differentiation

microRNAs (miRNAs) have been reported to play an essential role in the regulation of brown adipocyte adipogenesis. In the present study, we investigated the role of the miR-106b-93 cluster in the differentiation of brown adipocytes. We found that knockdown of miR-106b and miR-93 significantly induced the expression of brown fat-specific genes and promoted the accumulation of lipid-droplet in differentiating brown adipocytes. In addition, ectopic expression of miR-106b and miR-93 suppressed the mRNA level of Ucp1, a selective hallmark of brown adipocytes. Furthermore, the expression levels of miR-106b and miR-93 are higher in brown adipose tissues of high fat diet-induced obese mice compared to control mice. Taken together, our results identify miR-106b and miR-93 as negative regulators of brown adipocyte differentiation and the miR-106b-93 cluster may play an important role in regulating energy homeostasis.

Effects of MicroRNA-106 on Proliferation of Gastric Cancer Cell through Regulating p21 and E2F5

To investigate the effects of miR-106b on malignant characteristics of gastric cancer cells, and explore possible mechanisms. Expression of miR-106b, p21 and E2F was determined by real-time PCR. Transfection with miR-106b mimics was conducted, and gastric cancer cells with miR-106b overexpression were obtained. Cells transfected with mimic mutants and those without transfection served as negative and blank controls, respectively. Flow cytometry and transwell assays were adopted to detect the effects of miR-106b overexpression on cell cycle, migration and invasion of gastric cancer cells. . The expression of miR- 106b in gastric cancer cells was significantly higher than that in normal gastric mucosa cells. Furthermore, the expression level of miR-106b rose according to the degree of malignacy among the three GC cell strains (MKN- 45 > SGC-7901 > MKN-28). Overexpression of miR-106b shortened the G0/G1 phase and accelerated cell cycle progression, while reducing p21 and E2F5, without any significant effects on the capacity for migration and invasion of gastric cancer cells. miR-106b may promote cell cycling of gastric cancer cells through regulation of p21 and E2F5 target gene expression.

Repression of the miR-17-92 cluster by p53 has an important function in hypoxia-induced apoptosis

We here report that miR-17-92 cluster is a novel target for p53-mediated transcriptional repression under hypoxia. We found the expression levels of miR-17-92 cluster were reduced in hypoxia-treated cells containing wild-type p53, but were unchanged in hypoxia-treated p53-deficient cells. The repression of miR-17-92 cluster under hypoxia is independent of c-Myc. Luciferase reporter assays mapped the region responding to p53-mediated repression to a p53-binding site in the proximal region of the miR-17-92 promoter. Chromatin immunoprecipitation (ChIP), Re-ChIP and gel retardation assays revealed that the binding sites for p53- and the TATA-binding protein (TBP) overlap within the miR-17-92 promoter; these proteins were found to compete for binding. Finally, we show that pri-miR-17-92 expression correlated well with p53 status in colorectal carcinomas. Over-express miR-17-92 cluster markedly inhibits hypoxia-induced apoptosis, whereas blocked miR-17-5p and miR-20a sensitize the cells to hypoxia-induced apoptosis. These data indicated that p53-mediated repression of miR-17-92 expression likely has an important function in hypoxia-induced apoptosis, and thus further our understanding of the tumour suppressive function of p53.