Target Of miR-148a Research Articles

Abstract 190: Serum HDL-C Decreases in MicroRNA-33b Knock-in Mice for an Intron of Sterol Regulatory Element-binding Factor 1 (Srebf1)

Background: MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports, including ours, indicated that miR-33 (miR-33a) located within the intron of sterol regulatory element-binding factor (SREBF) 2 controls cholesterol homeostasis. Primates, but not rodents, express a second miR-33 gene (miR-33b) from an intron of SREBF1. To address miR-33b function in vivo, we developed humanized mice, in which a miR-33b transgene is inserted within a Srebf1 intron. Methods: The human miR-33b sequence was introduced into intron 16 of mouse Srebf1 because miR-33b is located in intron 16 of human SREBF1 and there are high homologies in exons 16 and 17 between human and mouse. The expression of serum miRNA was normalized with cel-miR-39 as a spike-in control. Results: We successfully established miR-33b knock-in (KI) mice with C57BL/6 background and this miR-33b KI strategy did not alter Srebf1 intron 16 splicing, which was confirmed by RT-PCR and sequencing. An LXR agonist T0901317, which induces Srebf1 expression, enhanced miR-33b expression in primary hepatocytes and the liver of miR-33 KI mice. The protein levels of known miR-33a target genes, such as ABCA1, ABCG1, and SREBP-1, were reduced compared with those in wild-type mice. Peritoneal macrophages from the miR-33b KI mice had a reduced cholesterol efflux capacity via apoA-I and HDL-C. Serum HDL-C levels were reduced by almost 35% in miR-33b KI mice. HPLC elution analysis showed that the decreased HDL-C levels were mainly composed of very large-, large-, medium sized HDL-C, which was compatible with the previous results of miR-33a deficient mice. Next, we measured miR-33b levels in serum of human. The expressions of miR-33b-3p were inversely correlated with serum HDL-C levels (P=0.025, R=0.336). Conclusions: miR-33b KI mice for an intron of Srebf1 showed reduced HDL-C level and serum miR-33b-3p levels were inversely correlated with HDL-C levels in human. These results indicate that miR-33b can be a potential target for raising HDL-C and may account for lower HDL-C levels in humans than those in mice. These mice will aid in elucidating the roles of miR-33s and screening of the drugs that can alter miR-33s levels and activities.

MiR-125a suppresses tumor growth, invasion and metastasis in cervical cancer by targeting STAT3.

MiR-125a has been characterized as a tumor suppressor in several cancers. However, the role of miR-125a in cervical cancer is unknown. In this study, we found the expression of miR-125a was downregulated in cervical cancer patients, and negatively correlated with the tumor size, FIGO stage, and preoperative metastasis. Kaplan-Meier analysis showed that miR-125a expression predicted favorable outcome for cervical cancer patients. Dual luciferase assays identified the STAT3 gene as a novel direct target of miR-125a. Functional studies showed that miR-125a overexpression significantly suppressed the growth, invasion and epithelial-mesenchymal transition (EMT) of cervical cancer cells both in vitro and in vivo via decreasing STAT3 expression. Moreover, miR-125a conferred to G2/M cell cycle arrest, accompanied by inhibition of several G2/M checkpoint proteins. Mechanistically, inactivation of miR-125a during cervical carcinogenesis was caused by HPV suppression of p53 expression. Clinically, STAT3, the expression of which, predicted poorer outcome, was inversely correlated with miR-125a in cervical cancer. These data highlight the importance of miR-125a in the cell proliferation and progression of cervical cancer, and indicate that miR-125a may be a useful therapeutic target for cervical cancer.

Understanding thrombocytopenia: physiological role of microRNA in survival of neonatal megakaryocytes.

Neonates are predisposed to developing thrombocytopenia and neonates are affected by megakaryocytic disorders such as thrombocytopenia with absent radius syndrome and transient myeloproliferative disorder. Small double stranded non-coding microRNAs (miRNAs) have been shown to crucially involve in the regulation of stem-cell differentiation in normal as well as malignant haematopoiesis. The regulatory mechanism in developmental megakaryocytopoiesis and role of miRNAs in biological differences between adult and neonatal megakaryopoiesis is unknown. Here in we compared miR-99a levels in megakaryocytes (MKs) derived from cord blood (CB) and peripheral blood using qRT-PCR. CTDSPL is predicted as potential target of miR-99a and was confirmed by western blot. CTDSPL is shown to involve in regulation of cell growth and differentiation and exhibits tumor suppressor activity. We believe that miR-99a regulates CTDSPL, which induces the G1/S transition by increasing Cyclin expression and play a significant role in proliferation of CB-MKs.

Differential expression of microRNA in paraffin-embedded tissue in patients with multiple and solitary gliomas: a preliminary study

Objectives To compare the differences of microRNA (miRNA) expression profile of multiple and solitary gliomas in formalin-fixed and paraffin embedded (FFPE) tissue and to preliminarily investigate the possible roles in glioma invasion and migration for the significantly different miRNA and its target genes. Methods FFPE specimens in patients with multiple glioma (n=6) and solitary glioma (n=6) were selected. The total RNA was extracted and detected; the gene chip technology was used to detect miRNA expression profile. The chip analysis software was used to analyze the data of the results. The miRNAs of significant expression differences of the multiple and solitary gliomas were screened. Then the biological information database was used to predict the target genes of miRNA of the most significant expression differences. Results The total RNA quality extracted from all the FFPE tissue specimens met the standard of quality control. There were significant differences in 128 different miRNAs in the multiple glioma compared with the solitary glioma (multiple >5 or 50), they were miR-21, miR-455, miR-199, miR-410, miR-148a, miR-335, miR-34b, miR-664a, miR-542, and miR-4453, respectively. Five miRNAs were significantly downregulated (multiple <0.05), they were miR-200a, miR-451, miR-29a, miR-101, and miR-96. Based on the most significant prediction results of the miR-21 and miR-200a target genes of upregulation and downregulation, their multiple target genes involved in tumor invasion and migration related biological function. Conclusions FFPE tissue may meet the subsequent experimental study, such as miRNA chip, etc. and thus provide rich resources for the research of the miRNA biological function and exploration. Multiple glioma has differential expression of miRNA compared with solitary glioma, in which miR-21and miR-200a may be closely associated with the invasion and migration of glioma. Key words: Glioma; MicroRNAs; Microchip analytical procedures; Neoplasm invasiveness; Cell migration

MiR-125a targets effector programs to stabilize Treg-mediated immune homeostasis.

Although different autoimmune diseases show discrete clinical features, there are common molecular pathways intimately involved. Here we show that miR-125a is downregulated in peripheral CD4(+) T cells of human autoimmune diseases including systemic lupus erythematosus and Crohn's disease, and relevant autoimmune mouse models. miR-125a stabilizes both the commitment and immunoregulatory capacity of Treg cells. In miR-125a-deficient mice, the balance appears to shift from immune suppression to inflammation, and results in more severe pathogenesis of colitis and experimental autoimmune encephalomyelitis (EAE). The genome-wide target analysis reveals that miR-125a suppresses several effector T-cell factors including Stat3, Ifng and Il13. Using a chemically synthesized miR-125a analogue, we show potential to re-programme the immune homeostasis in EAE models. These findings point to miR-125a as a critical factor that controls autoimmune diseases by stabilizing Treg-mediated immune homeostasis.

MicroRNA-33a regulates cholesterol synthesis and cholesterol efflux related genes in osteoarthritic chondrocytes

Several studies have shown that osteoarthritis (OA) is strongly associated with metabolism-related disorders, highlighting OA as the fifth component of the metabolic syndrome (MetS). On the basis of our previous findings on dysregulation of cholesterol homeostasis in OA, we were prompted to investigate whether microRNA-33a (miR-33a), one of the master regulators of cholesterol and fatty acid metabolism, plays a key role in OA pathogenesis. Articular cartilage samples were obtained from 14 patients with primary OA undergoing total knee replacement surgery. Normal cartilage was obtained from nine individuals undergoing fracture repair surgery. Bioinformatics analysis was used to identify miR-33a target genes. miR-33a and sterol regulatory element-binding protein 2 (SREBP-2) expression levels were investigated using real-time PCR, and their expression was also assessed after treatment with transforming growth factor-β1 (TGF-β1) in cultured chondrocytes. Akt phosphorylation after treatment with both TGF-β1 and miR-33a inhibitor or TGF-β1 and miR-33a mimic was assessed by Western blot analysis. Furthermore, we evaluated the effect of miR-33a mimic and miR-33a inhibitor on Smad7, a negative regulator of TGF-β signaling, on cholesterol efflux-related genes, ATP-binding cassette transporter A1 (ABCA1), apolipoprotein A1 (ApoA1) and liver X receptors (LXRα and LXRβ), as well as on matrix metalloproteinase-13 (MMP-13), using real-time PCR. We found that the expression of miR-33a and its host gene SREBP-2 was significantly elevated in OA chondrocytes compared with normal chondrocytes. Treatment of cultured chondrocytes with TGF-β1 resulted in increased expression of both miR-33a and SREBP-2, as well as in rapid induction of Akt phosphorylation, whereas TGF-β-induced Akt phosphorylation was enhanced by miR-33a and suppressed by inhibition of miR-33a, as a possible consequence of Smad7 regulation by miR-33a. Moreover, treatment of normal chondrocytes with miR-33a resulted in significantly reduced ABCA1 and ApoA1 mRNA expression levels and significantly elevated MMP-13 expression levels, promoting the OA phenotype, whereas miR-33a’s suppressive effect was reversed using its inhibitor. Our findings suggest, for the first time to our knowledge, that miR-33a regulates cholesterol synthesis through the TGF-β1/Akt/SREBP-2 pathway, as well as cholesterol efflux-related genes ABCA1 and ApoA1, in OA chondrocytes, pointing to its identification as a novel target for ameliorating the OA phenotype.

MiR-148a promotes plasma cell differentiation and targets the germinal center transcription factors Mitf and Bach2.

Bcells undergo affinity maturation and class switch recombination of their immunoglobulin receptors during a germinal center (GC) reaction, before they differentiate into long-lived antibody-secreting plasma cells (PCs). Transcription factors such as Bach2 and Mitf are essential during this process, as they delay premature differentiation of GC Bcells by repressing Blimp-1 and IRF4, two transcription factors required for terminal PC differentiation. Therefore, Bach2 and Mitf expression must be attenuated in activated Bcells to allow terminal PC differentiation, but the precise mechanism remains enigmatic. Here, we provide evidence that miR-148a, a small noncoding microRNA, fosters PC differentiation and survival. Next-generation sequencing revealed that miR-148a is the most abundant microRNA in primary human and murine PCs, and its expression is upregulated in activated murine Bcells and coincides with Blimp-1 synthesis. miR-148a targets Bach2, Mitf and proapoptotic factors such as PTEN and Bim. When prematurely expressed, miR-148a promotes the differentiation and survival of plasmablasts and reduces frequencies of IgG1(+) cells in primary B-cell cultures. In summary, we propose that miR-148a is a new player in the regulatory network controlling terminal PC differentiation and could, therefore, be a therapeutic target for interfering with PC differentiation and survival.

MicroRNA-33a regulates cholesterol synthesis and cholesterol efflux-related genes in osteoarthritic chondrocytes.

IntroductionSeveral studies have shown that osteoarthritis (OA) is strongly associated with metabolism-related disorders, highlighting OA as the fifth component of the metabolic syndrome (MetS). On the basis of our previous findings on dysregulation of cholesterol homeostasis in OA, we were prompted to investigate whether microRNA-33a (miR-33a), one of the master regulators of cholesterol and fatty acid metabolism, plays a key role in OA pathogenesis.MethodsArticular cartilage samples were obtained from 14 patients with primary OA undergoing total knee replacement surgery. Normal cartilage was obtained from nine individuals undergoing fracture repair surgery. Bioinformatics analysis was used to identify miR-33a target genes. miR-33a and sterol regulatory element-binding protein 2 (SREBP-2) expression levels were investigated using real-time PCR, and their expression was also assessed after treatment with transforming growth factor-β1 (TGF-β1) in cultured chondrocytes. Akt phosphorylation after treatment with both TGF-β1 and miR-33a inhibitor or TGF-β1 and miR-33a mimic was assessed by Western blot analysis. Furthermore, we evaluated the effect of miR-33a mimic and miR-33a inhibitor on Smad7, a negative regulator of TGF-β signaling, on cholesterol efflux-related genes, ATP-binding cassette transporter A1 (ABCA1), apolipoprotein A1 (ApoA1) and liver X receptors (LXRα and LXRβ), as well as on matrix metalloproteinase-13 (MMP-13), using real-time PCR.ResultsWe found that the expression of miR-33a and its host gene SREBP-2 was significantly elevated in OA chondrocytes compared with normal chondrocytes. Treatment of cultured chondrocytes with TGF-β1 resulted in increased expression of both miR-33a and SREBP-2, as well as in rapid induction of Akt phosphorylation, whereas TGF-β-induced Akt phosphorylation was enhanced by miR-33a and suppressed by inhibition of miR-33a, as a possible consequence of Smad7 regulation by miR-33a. Moreover, treatment of normal chondrocytes with miR-33a resulted in significantly reduced ABCA1 and ApoA1 mRNA expression levels and significantly elevated MMP-13 expression levels, promoting the OA phenotype, whereas miR-33a’s suppressive effect was reversed using its inhibitor.ConclusionsOur findings suggest, for the first time to our knowledge, that miR-33a regulates cholesterol synthesis through the TGF-β1/Akt/SREBP-2 pathway, as well as cholesterol efflux-related genes ABCA1 and ApoA1, in OA chondrocytes, pointing to its identification as a novel target for ameliorating the OA phenotype.

MiR-148a, a microRNA upregulated in the WNT subgroup tumors, inhibits invasion and tumorigenic potential of medulloblastoma cells by targeting Neuropilin 1.

Medulloblastoma, a common pediatric malignant brain tumor consists of four molecular subgroups viz. WNT, SHH, Group 3 and Group 4. MiR-148a is over-expressed in the WNT subgroup tumors, which have the lowest incidence of metastasis and excellent survival among all medulloblastomas. MiR-148a was expressed either in a transient manner using a synthetic mimic or in a stable doxycycline inducible manner using a lentiviral vector in non-WNT medulloblastoma cell lines. Expression of miR-148a to levels comparable to that in the WNT subgroup tumors was found to inhibit proliferation, clonogenic potential, invasion potential and tumorigenicity of medulloblastoma cells. MiR-148a expression in medulloblastoma cells brought about reduction in the expression of NRP1, a novel miR-148a target. Restoration of NRP1 expression in medulloblastoma cells was found to rescue the reduction in the invasion potential and tumorigenicity brought about by miR-148a expression. NRP1 is known to play role in multiple signaling pathways that promote tumor growth, invasion and metastasis. NRP1 expression in medulloblastomas was found to be associated with poor survival, with little or no expression in majority of the WNT tumors. The tumor suppressive effect of miR-148a expression accompanied by the down-regulation of NRP1 makes miR-148a an attractive therapeutic agent for the treatment of medulloblastomas.

Targeting of YAP1 by microRNA-15a and microRNA-16-1 exerts tumor suppressor function in gastric adenocarcinoma.

BackgroundMicroRNAs (miRNAs) have been reported to play an important role in tumorigenesis. In this study, the role of miR-15a and miR-16-1 in gastric adenocarcinoma (GAC) was investigated.MethodsThe expression of miR-15a and miR-16-1 in cell lines and primary tumors was examined by miRNA qRT-PCR. Proliferative assays, colony formation, cell invasion and migration, flow cytometry analysis and in vivo study were performed by ectopic expression of miR-15a and miR-16-1. The putative target genes of miR-15a and miR-16-1 were explored by TargetScan and further validated.ResultsWe found that miR-15a and miR-16-1 were down-regulated in GAC cell lines and primary tumor samples compared with normal gastric epithelium. Functional study demonstrated that ectopic expression of miR-15a and miR-16-1 suppressed cell proliferation, monolayer colony formation, invasion and migration, and xenograft formation in vivo. In addition, miR-15a and miR-16-1 induced G0/G1 cell cycle arrest which was further confirmed by Western blot and qRT-PCR of related cell cycle regulators. YAP1 was confirmed to be a functional target of miR-15a and miR-16-1 in GAC. YAP1 re-expression partly abrogated the inhibitory effect of miR-15a and miR-16-1 in GAC cells. In clinical samples, YAP1 protein expression shows negative correlation with miR-15a and miR-16-1 expression.ConclusionIn conclusion, targeting YAP1 by tumor suppressor miRNA miR-15a and miR-16-1 plays inhibitory effect and this might have a therapeutic potential in GAC.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-015-0323-3) contains supplementary material, which is available to authorized users.

MicroRNA-15a induces cell apoptosis and inhibits metastasis by targeting BCL2L2 in non-small cell lung cancer.

MicroRNAs (miRNAs) play a critical role in cancer development and progression. Aberrant expression of miR-15a has recently been reported in several cancers, but its role in non-small cell lung cancer (NSCLC) still remains obscure. We investigated the effects of miR-15a on proliferation, apoptosis, and metastasis in A549 cells. Eighteen paired NSCLC and adjacent non-tumor lung tissues were surgically removed and immediately snap frozen until total RNA was extracted and confirmed by two independent pathologists. The targets of miR-15a were predicted by bioinformatics tools. RNA isolation and quantitative real-time PCR (qRT-PCR), Western blot analysis, cell proliferation assay, cell cycle analysis, cell apoptosis assay, and migration and invasion assays were done. The wild type (WT) or mutant type (MT) 3'-untranslated region (UTR) vectors were co-transfected with miR-15a or negative control into A549 cells, and after 24 h of transfection, luciferase activity was measured using the Dual-Glo luciferase assay kit. Statistical analysis was performed using SPSS 13.0 software (SPSS, Chicago, IL, USA). P values of less than 0.05 were considered statistically significant. miR-15a was significantly downregulated in NSCLC than in adjacent non-cancerous tissues. miR-15a overexpression remarkably inhibited cell viability, invasion, and migration and promoted the apoptosis of NSCLC cells. Additionally, inhibition of miR-15a expression had the opposite effects on tumor progression, while cell cycle remained unaltered. Furthermore, we identified that BCL2L2 was a target of miR-15a and negatively regulated by miR-15a at the translational level. miR-15a acts as a tumor suppressor in NSCLC by directly targeting BCL2L2 and may serve as a potential diagnostic biomarker and therapeutic target for NSCLC.

Hepatitis B virus regulates apoptosis and tumorigenesis through the microRNA-15a-Smad7-transforming growth factor beta pathway.

Hepatitis B virus (HBV) infection causes chronic hepatitis in hundreds of millions of people worldwide, which can eventually lead to hepatocellular carcinoma (HCC). Previously, we found that HBV mRNAs can absorb microRNA-15a (miR-15a) to affect apoptosis through the Bcl-2 pathway. We asked whether HBV could inhibit apoptosis and promote tumorigenesis through different pathways. In this study, we found that the transforming growth factor β (TGF-β) pathway-inhibitory factor Smad7 is a novel target of miR-15a. We demonstrated that HBV can upregulate the level of Smad7 by downregulating miR-15a. Furthermore, we examined the level of Smad7 in liver samples from HBV-infected HCC patients and found that HBV mRNAs are positively correlated with the level of Smad7. By taking the approach of using immunoblotting and luciferase reporter assays, we revealed that HBV can abrogate TGF-β signaling via upregulating Smad7. By using annexin V staining and caspase 3/7 activity assays, we found that HBV can inhibit TGF-β-induced apoptosis of HepG2 cells. We also showed that HBV can promote tumor growth in BALB/c nude mice through upregulating the expression of Smad7. In conclusion, we demonstrated that HBV can upregulate Smad7 expression and inhibit TGF-β signaling, which makes the cells resistant to TGF-β-induced apoptosis and promotes tumorigenesis. Hepatitis B virus (HBV) infection causes chronic hepatitis, which can eventually lead to hepatocellular carcinoma (HCC). TGF-β signaling is closely linked to liver fibrosis, cirrhosis, and subsequent HCC progression and plays a unique role in the pathogenesis of HCC. At the early stage of tumor formation, TGF-β functions as a tumor suppressor that inhibits cell proliferation and induces apoptosis. Previously, we found that HBV mRNAs can sponge off miR-15a to affect apoptosis through the Bcl-2 pathway. In this study, we identified that the TGF-β-inhibitory factor Smad7 is a novel target of miR-15a. We reveal that HBV can abrogate TGF-β signaling via upregulating Smad7, inhibit TGF-β-induced apoptosis, as well as promote tumor development. Our study provides evidence to support the idea that viral RNAs can exert their functions as competing endogenous RNAs (ceRNAs) toward microRNA and participate in important cellular processes.

MicroRNA-148a inhibits hepatocellular carcinoma cell invasion by targeting sphingosine-1-phosphate receptor 1.

microRNA (miR)-148a has been shown to act as an important suppressor in numerous human malignancies and is markedly downregulated in hepatocellular carcinoma; however, the role of miR-148a in the regulation of hepatocellular carcinoma cell invasion, as well as the underlying mechanism, has never been studied. In the present study, the expression level of miR-148a was found to be significantly decreased in hepatocellular carcinoma tissues and HepG2 cells when compared with that in the normal adjacent tissues. Furthermore, a novel target of miR-148a was found, sphingosine-1-phosphate receptor 1 (S1PR1), whose expression was negatively regulated by miR-148a at a post-transcriptional level in hepatocellular carcinoma HepG2 cells. Upregulation of miR-148a by transfection with miR-148a mimics notably suppressed HepG2 cell invasion, similar to the effect of the SIPR1 downregulation induced by SIPR1-specific small interfering RNA, while the restoration of S1PR1 expression reversed the inhibitory effect of miR-148a upregulation on HepG2 cell invasion. Accordingly, the current study suggests that miR-148a plays an inhibitory role in the regulation of hepatocellular carcinoma cell invasion by directly targeting S1PR1.

Abstract 13545: MicroRNA-33b Knock-in Mice for an Intron of Sterol Regulatory Element-Binding Factor 1 (Srebf1) Exhibit Reduced HDL-C in vivo

Background: MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports, including ours, indicated that miR-33 (miR-33a) located within the intron of sterol regulatory element-binding protein (SREBP) 2 controls cholesterol homeostasis and can be a possible therapeutic target for treating atherosclerosis. Primates, but not rodents, express a second miR-33 gene (miR-33b) from an intron of SREBF1. To address miR-33b function in vivo, we developed humanized mice, in which a miR-33b transgene is inserted within a Srebf1 intron. Methods and Results: The human miR-33b sequence was introduced into intron 16 of mouse Srebf1 by conventional gene targeting methods, because miR-33b is located in intron 16 of human SREBF1 and there are high homologies in exons 16 and 17 between human and mouse. We successfully established miR-33b knock-in (KI) mice with C57BL/6 background and this miR-33b KI strategy did not alter Srebf1 intron 16 splicing, which was confirmed by RT-PCR and sequencing. The expression of miR-33b in miR-33b KI hetero mice were almost half of those in miR-33b KI homo mice. An LXR agonist T0901317, which induces Srebf1 expression, enhanced miR-33b expression in primary hepatocytes and the liver of miR-33 KI homo mice. The protein levels of known miR-33a target genes, such as ABCA1, ABCG1, and SREBP-1, were reduced compared with those in wild-type mice. Peritoneal macrophages from the miR-33b KI mice had a reduced cholesterol efflux capacity via apoA-I and HDL-C. Serum HDL-C levels were reduced by almost 35% even in miR-33b KI hetero mice compared with wild-type mice. HPLC elution analysis showed that the decreased HDL levels were mainly composed of very large-, large-, medium sized HDL, which was compatible with the previous results of miR-33a deficient mice. Conclusions: miR-33b KI mice for an intron of Srebf1 showed reduced HDL-C levels. These results indicate that miR-33b can be a potential target for raising HDL-C in humans and may account for lower HDL-C levels in humans than those in mice. These mice will aid in elucidating the roles of miR-33s in different disease models and in screening of the drugs that can alter miR-33a and miR-33b levels and activities.

A genetic variant of miR-148a binding site in the SCRN1 3'-UTR is associated with susceptibility and prognosis of gastric cancer.

Single nucleotide polymorphisms (SNPs) in the 3′-untranslated regions targeted by putative mircoRNA can change its binding strength, affecting the susceptibility and prognosis of cancer. We aimed to investigate the associations between SNPs within miR-148a binding sites and gastric cancer (GC) risk and prognosis. Using bioinformatics tools, we selected two SNPs (SCRN1 rs6976789 and PDYN rs2235749) located in miR-148a target sites. We genotyped the two SNPs in a case-control study comprising 753 GC patients and 949 cancer-free subjects. We found a significantly increased risk of GC associated with the SCRN1 rs6976789 C>T polymorphism [adjusted OR = 1.25, 95% confidence interval (CI) = 1.02–1.53; CT/TT vs. CC]. However, no significant association was found between the PDYN rs2235749 and GC risk in all genetic models. Furthermore, we evaluated whether SCRN1 rs6976789 affected the survival of GC patients. Results showed that individuals with SCRN1 rs6976789 TT genotype had poorer overall survival compared with those carried CC/CT genotypes in intestinal-type GC (adjusted HR = 2.47, 95% CI = 1.21–5.05). Luciferase report assay showed that the rs6976789 variant T allele influenced the binding ability of miR-148a. Our results suggested that the SCRN1 rs6976789 polymorphism may play an important role in the GC development and progression.

MiR-199a regulates cell proliferation and survival by targeting FZD7.

A growing amount of evidence indicates that miRNAs are important regulators of multiple cellular processes and, when expressed aberrantly in different types of cancer such as hepatocellular carcinoma (HCC), play significant roles in tumorigenesis and progression. Aberrant expression of miR-199a-5p (also called miR-199a) was found to contribute to carcinogenesis in different types of cancer, including HCC. However, the precise molecular mechanism is not yet fully understood. The present study showed that miR-199a is frequently down-regulated in HCC tissues and cells. Importantly, lower expression of miR-199a was significantly correlated with the malignant potential and poor prognosis of HCC, and restoration of miR-199a in HCC cells led to inhibition of the cell proliferation and cell cycle in vitro and in vivo. Furthermore, Frizzled type 7 receptor (FZD7), the most important Wnt receptor involved in cancer development and progression, was identified as a functional target of miR-199a. In addition, these findings were further strengthened by results showing that expression of FZD7 was inversely correlated with miR-199a in both HCC tissues and cells and that over-expression of miR-199a could significantly down-regulate the expression of genes downstream of FZD7, including β-catenin, Jun, Cyclin D1 and Myc. In conclusion, these findings not only help us to better elucidate the molecular mechanisms of hepatocarcinogenesis from a fresh perspective but also provide a new theoretical basis to further investigate miR-199a as a potential biomarker and a promising approach for HCC treatment.

MiR-10a inhibits dendritic cell activation and Th1/Th17 cell immune responses in IBD

ObjectiveAlthough both innate and adaptive responses to microbiota have been implicated in the pathogenesis of IBD, it is still largely unknown how they are regulated during intestinal inflammation. In this...

Abstract 5239: MiR-148a promotes apoptosis in urothelial cell carcinoma of the bladder cells in part by targeting DNMT1

Abstract Introduction: MiRNAs are now recognized as major players in cancer. MiR-148a has been shown to be a tumor suppressor in the context of several cancers including prostate, gastric, and lung but a study investigating its role in bladder cancer has never been performed. Here we characterized the expression and role of miR-148a in bladder cancer. Methods: Real time PCR was used to assess the levels of miR-148a across several bladder cancer cell lines. MiR-148a mimics were employed in T24 and UM-UC-3 cells to assess proliferation by CCK-8 proliferation assay, colony formation assay, and flow cytometry. Mimics were also used to assess apoptosis by immunoblot and annexin-V staining coupled to flow cytometry. Immunoblot was used to probe for targets of miR-148a and siRNA was used to knock-down DNMT1 to phenocopy miR-148a treatment results. CCK-8 proliferation assays and crystal violet staining were used to assess the additive effects of miR-148a with either cisplatin or doxorubicin on T24 and UM-UC-3 cells and CCK-8 proliferation assays were also used to assess the role DNMT1 plays in cisplatin sensitivity. Results: All bladder cancer cell lines had significantly reduced expression of miR-148a than that of a control immortalized urothelial cell line. MiR-148a mimic treatment of T24 and UM-UC-3 cells led to large decreases in viability. Flow cytometry demonstrated an increase in S-phase and no major G1 or G2/M arrests in miR-148a mimic treated cells versus control oligo treated cells suggesting that the effects observed on viability were due to increased apoptosis. Immunoblots for cleaved caspase-3 and cleaved PARP along with annexin-V staining coupled to flow cytometry showed as expected a strong induction of apoptosis in miR-148a mimic treated cells. Immunoblots demonstrated that miR-148a targets DNMT1 and DNMT1 knock-down was able to partially phenocopy results from miR-148a mimic treatment suggesting DNMT1 is downstream of miR-148a. Finally, we found that miR-148a can be used with either cisplatin or doxorubicin for an additive effect in inducing apoptosis and that DNMT1 targeting is involved in sensitivity to cisplatin. Conclusions: Our work demonstrates for the first time that miR-148a plays a tumor suppressive role in bladder cancer and suggests it could be used as a novel therapeutic agent either alone or in conjunction with chemotherapeutics. Citation Format: Alan Lombard, Ben Mooso, Steve Libertini, Rebecca Lim, Nicole Costanzo, Paramita Ghosh, Maria Mudryj. MiR-148a promotes apoptosis in urothelial cell carcinoma of the bladder cells in part by targeting DNMT1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5239. doi:10.1158/1538-7445.AM2014-5239

Abstract 5222: microRNA-148a is a prognostic oncomiR that targets MIG6 and BIM to regulate EGFR and apoptosis in glioblastoma

Abstract In this study, we uncovered microRNA-148a (miR-148a) as a novel prognostic and oncogenic microRNA in glioblastoma (GBM). MiR-148a expression was significantly higher in human GBM tissues, cell lines and stem cells (GSCs) as compared to normal human brain and astrocytes. High miR-148a levels were a risk indicator for GBM patient survival. MiR-148a increased GBM cell and GSC growth, survival, migration, and invasion as well as GSC neurosphere formation. We identified the EGFR regulator, MIG6, and the apoptosis regulator, BIM as two direct targets of miR-148a and showed with rescue experiments that they mediate the oncogenic effects of miR-148a. Importantly, by inhibiting MIG6 expression, miR-148a reduced EGFR trafficking to the Rab7-expressing late endosome/lysosomal compartments. This coincided with a reduction of EGFR degradation and induction of EGFR expression and activation. Lastly, inhibition of miR-148a expression led to a strong inhibition of GSC and GBM xenograft growth in vivo. These findings represent the first comprehensive analysis of the role of miR-148a in GBM. They show that miR-148a expression levels are predictive of patient survival and that this microRNA enhances malignancy by inhibiting apoptosis and indirectly activating EGFR. These results also suggest that miR-148a is a potential target for GBM therapy. Citation Format: Jungeun Kim, Ying Zhang, Michael Skalski, Josie Hayes, Benjamin Kefas, David Schiff, Benjamin Purow, Sarah Parsons, Sean Lawler, Roger Abounader. microRNA-148a is a prognostic oncomiR that targets MIG6 and BIM to regulate EGFR and apoptosis in glioblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5222. doi:10.1158/1538-7445.AM2014-5222

Silencing of miRNA-148a by hypermethylation activates the integrin-mediated signaling pathway in nasopharyngeal carcinoma.

MicroRNAs (miRNAs) play a pivotal role in carcinogenesis by suppressing oncogenes or tumor suppressor genes. Various studies have identified numerous miRNAs and their diverse targets; however, the consequences of dysregulated miRNAs in nasopharyngeal carcinoma (NPC) remain unclear. For this study, we found that miR-148a is downregulated through hypermethylation in NPC biopsies and NPC cell lines compared with adjacent normal and NP cells respectively. Promoter assays demonstrated that upstream stimulatory factor 1 (USF1) is a crucial transcription factor that activates miR-148a promoter activity. EMSA assays confirmed that purified USF1 binds better toward the unmethylated than the methylated CG-containing USF1 consensus probe. The ectopic expression of miR-148a inhibits cell migration in NPC cells through the suppression of integrin-mediated signaling by targeting VAV2, WASL and ROCK1. Biochemical and functional assays provided supporting evidence that these 3 genes are the downstream targets of miR-148a in NPC cells. Furthermore, immunohistochemical staining and Western blotting analysis revealed that the 3 oncogenic targets of miR-148a were overexpressed in NPC biopsies, suggesting that the inactivation of miR-148a caused by DNA methylation promotes NPC progression. Overall, our findings revealed that miR-148a can act as tumor suppressor miRNA and serve as a biomarker as well as a therapeutic target for NPC.