HMGA2 functions as a competing endogenous RNA to promote lung cancer progression

Interaction network of coexpressed mRNA, miRNA, and lncRNA activated by TGF‑β1 regulates EMT in human pulmonary epithelial cell

Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), play increasingly important roles in pathological processes involved in disease development. However, whether mRNAs interact with miRNAs and lncRNAs to form an interacting regulatory network in diseases remains unknown. In this study, the interaction of coexpressed mRNAs, miRNAs and lncRNAs during tumor growth factor-β1-activated (TGF-β1) epithelial-mesenchymal transition (EMT) was systematically analyzed in human alveolar epithelial cells. For EMT regulation, 24 mRNAs, 11 miRNAs and 33 lncRNAs were coexpressed, and interacted with one another. The interaction among coexpressed mRNAs, miRNAs and lncRNAs were further analyzed, and the results showed the lack of competing endogenous RNAs (ceRNAs) among them. The mutual regulation may be correlated with other modes, such as histone modification and transcription factor recruitment. However, the possibility of ceRNA existence cannot be ignored because of the generally low abundance of lncRNAs and frequent promiscuity of protein-RNA interactions. Thus, conclusions need further experimental identification and validation. In this context, disrupting many altered disease pathways remains one of the challenges in obtaining effective pathway-based therapy. The reason being that one specific mRNA, miRNA or lncRNA may target multiple genes that are potentially implicated in a disease. Nevertheless, the results of the present study provide basic mechanistic information, possible biomarkers and novel treatment strategies for diseases, particularly pulmonary tumor and fibrosis.

TET-Mediated Sequestration of miR-26 Drives EZH2 Expression and Gastric Carcinogenesis

DNA demethylases of the TET family function as tumor suppressors in various human cancers, but their pathogenic contributions and mechanisms of action in gastric carcinogenesis and progression remain unclear. Here, we report that TET is transcriptionally upregulated in gastric cancer, where it correlates with poor prognosis. Mechanistic investigations revealed that TET facilitated gastric carcinogenesis through a noncoding function of the 3'UTR, which interacted with miR-26. This interaction resulted in sequestration of miR-26 from its target EZH2, which released the suppression on EZH2, and thereby led to EZH2 overexpression in gastric cancer. Our findings uncover a novel noncoding function for TET family proteins in facilitating gastric carcinogenesis. Cancer Res; 77(22); 6069-82. ©2017 AACR.

MicroRNA-219 is downregulated in non-small cell lung cancer and inhibits cell growth and metastasis by targeting HMGA2

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer-associated mortality worldwide. Non-small cell lung cancer (NSCLC) is the predominant type of lung cancer, and accounts for ~85% of all lung cancer cases. An increasing number of studies suggest that microRNAs (miRs) may be involved in the regulation of NSCLC carcinogenesis and progression. However, the expression and function of miRNA-219 in NSCLC, and its underlying mechanisms of action, remain unknown. In the present study, miR-219 expression in NSCLC tissues and cell lines was determined using reverse transcription-quantitative polymerase chain reaction. Following transfection with miR-219 mimics, the effects of miR-219 overexpression on NSCLC cell proliferation, migration and invasion were examined. Furthermore, the miR-219 target in NSCLC was investigated. miR-219 was observed to be downregulated in NSCLC tissues and NSCLC cell lines. In addition, miR-219 was demonstrated to function as a tumor suppressor in NSCLC, through inhibiting cell proliferation, migration and invasion in vitro. Furthermore, high mobility group AT-hook 2 (HMGA2) was identified to be a direct target of miR-219 in NSCLC, and downregulation of HMGA2 suppressed NSCLC cell proliferation, migration and invasion in vitro. HMGA2 expression was upregulated in NSCLC tissues, and was inversely correlated with miR-219 expression. In conclusion, miR-219 functions as a tumor suppressor and may be important in inhibiting the growth and metastasis of NSCLC cells via directly targeting HMGA2. Therefore, miR-219 may present a potential novel therapeutic target for NSCLC.

PART-1 functions as a competitive endogenous RNA for promoting tumor progression by sponging miR-143 in colorectal cancer

LncRNAs were altered in several cancers and played a crucial role in various biological activities and progressions of different diseases, including proliferation, chemical resistance, and metastasis. In the present study, we revealed that prostrate androgen-regulated transcript-1 (PART-1) was highly expressed in colorectal cancer cells and tissues, and knockdown of PART-1 suppressed cell proliferation and metastasis, both in vitro and in vivo. In addition, PART-1 functioned as a ceRNA of DNMT3A, by sponging miR-143. Finally,PART-1 induced tumor progression by regulating DNMT3A.

HMGA2 plays an important role in Cr (VI)-induced autophagy

Cr (VI) is mutagenic and carcinogenic, but the mechanism is unclear. In this study, the involvement of high mobility group A2 (HMGA2) in Cr (VI)-induced autophagy was investigated. Cr (VI) treatment induced formation of autophagosomes, increased expression of LC3II, Atg12-Atg5, Atg4, Atg10, HMGA1 and HMGA2 proteins, and decreased the expression of p62 in A549 cells. Silencing of HMGA2 gene by siRNA blocked Cr (VI)-induced formation of autophagosomes, expression of LC3II, Atg12-Atg5, Atg10 and reduction of p62. Overexpression of HMGA2 in HEK 293 and HeLa cells could induce the expression of LC3II, Atg12-Atg5 and Atg10, and decrease the expression of p62. Although the protein level of Atg12-Atg5 conjugation changed after Cr (VI) treatment, silencing of HMGA2 and overexpression of HMGA2, both the proteins and mRNA levels of Atg12 and Atg5 were not changed significantly. ChIP assay demonstrated that HMGA2 protein directly bound to the promoter sequence of Atg10 gene, which modulated the conjugation of Atg12-Atg5. Interestingly, 3-MA markedly prevented Cr (VI)-induced cell growth of A549 cells. Our further in vivo study confirmed that the expression of HMGA1, HMGA2, LC3II, Atg12-Atg5, Atg4, Atg5, Atg7, Atg10, Atg12, Beclin 1 were increased and p62 was reduced in lung tissues of Cr (VI)-treated BALB/c mice. Combining, our data demonstrated that HMGA2 plays an important role in Cr (VI)-induced autophagy and the mechanism underlies Atg12-Atg5 conjugation modulated by HMGA2-dependent transcriptional regulation of Atg10. This suggests that HMGA2 might be an important biomarker in Cr (VI)-induced autophagy, cell-growth or other toxicities.

Following MicroRNAs Through the Cancer Metastatic Cascade

Approximately a decade ago the first MicroRNAs (MiRNAs) participating in cancer metastasis were identified and metastmiRs were initially only a handful. Since those first reports, MiRNA research has explosively thrived, mainly due to their revolutionary mechanism of action and the hope of having at hand a novel tool to control cancer aggressiveness. This has ultimately led to delineate an almost impenetrable regulatory network: hundreds of MiRNAs transversally dominating every aspect of normal and cancer biology, each MiRNA having hundreds of targets and context-dependent activity. Providing a comprehensive description of MiRNA roles in cancer metastasis is a daunting task; nevertheless, we still believe that grasping the big picture of MiRNAs in cancer metastasis can give a different perspective on the potential insights and approaches that MiRNAs can offer to understand cancer complexity (e.g., as predictive and prognostic markers) and to tackle cancer metastasis (e.g., as therapeutic targets or tools). This chapter presents a schematic overview of the role of MiRNAs in governing cancer metastasis, describing step by step the cellular and molecular processes whereby cancer cells conquer distant organs and can grow as secondary tumors at different distant sites, and for each step, we will introduce how MiRNAs impinge on each one of them. We deeply apologize with our colleagues for any of their research work that, for clarity, for our effort to streamline and due to space limitations, we did not cite.

High-throughput validation of ceRNA regulatory networks

Background

MicroRNAs (miRNAs) play multiple roles in tumor biology. Interestingly, reports from multiple groups suggest that miRNA targets may be coupled through competitive stoichiometric sequestration. Specifically, computational models predicted and experimental assays confirmed that miRNA activity is dependent on miRNA target abundance, and consequently, changes in the abundance of some miRNA targets lead to changes to the regulation and abundance of their other targets. The resulting indirect regulatory influence between miRNA targets resembles competition and has been dubbed competitive endogenous RNA (ceRNA). Recent studies have questioned the physiological relevance of ceRNA interactions, our ability to accurately predict these interactions, and the number of genes that are impacted by ceRNA interactions in specific cellular contexts.

Results

To address these concerns, we reverse engineered ceRNA networks (ceRNETs) in breast and prostate adenocarcinomas using context-specific TCGA profiles, and tested whether ceRNA interactions can predict the effects of RNAi-mediated gene silencing perturbations in PC3 and MCF7 cells._ENREF_22 Our results, based on tests of thousands of inferred ceRNA interactions that are predicted to alter hundreds of cancer genes in each of the two tumor contexts, confirmed statistically significant effects for half of the predicted targets.

Conclusions

Our results suggest that the expression of a significant fraction of cancer genes may be regulated by ceRNA interactions in each of the two tumor contexts.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3790-7) contains supplementary material, which is available to authorized users.

Endogenous miRNA Sponge LincRNA-ROR promotes proliferation, invasion and stem cell-like phenotype of pancreatic cancer cells

The long intergenic non-coding RNA, regulator of reprogramming (linc-ROR) is an oncogene and plays a key role in the embryonic stem cell maintenance and is involved in cancer progression. The objective of this study was to analyze linc-ROR expression in pancreatic ductal adenocarcinoma (PDAC) and determine the regulation effects of linc-ROR on proliferation and invasion of cancer cells, as well as properties of cancer stem-like cells (CSLCs). In this study, we found that linc-ROR was up-regulated in PDAC tissues and related to poor prognosis. Linc-ROR knockdown in pancreatic cancer cells inhibited cell growth and arrested in G1 phrase. Suppressed linc-ROR expression also attenuated cancer cell migration, invasion, and epithelial-mesenchymal transition. We observed that linc-ROR expression was increased in CSLCs. Importantly, linc-ROR knockdown impaired the properties and tumorigenesis of pancreatic CSLCs in vivo. Mechanistically, we found that linc-ROR functioned as a competing endogenous RNA (ceRNA) to several tumor suppressor microRNAs, particularly some members of let-7 family. We conclude that, as a crucial oncogene, linc-ROR promotes cell proliferation, invasiveness and contributes to stem cell properties of CSLCs in PDAC via acting as a ceRNA to regulate function of microRNAs. The linc-ROR is a potential therapeutic target for PDAC.

Comprehensive Analysis of Interaction Networks of Telomerase Reverse Transcriptase with Multiple Bioinformatic Approaches: Deep Mining the Potential Functions of Telomere and Telomerase

Telomerase reverse transcriptase (TERT) is the protein component of telomerase complex. Evidence has accumulated showing that the nontelomeric functions of TERT are independent of telomere elongation. However, the mechanisms governing the interaction between TERT and its target genes are not clearly revealed. The biological functions of TERT are not fully elucidated and have thus far been underestimated. To further explore these functions, we investigated TERT interaction networks using multiple bioinformatic databases, including BioGRID, STRING, DAVID, GeneCards, GeneMANIA, PANTHER, miRWalk, mirTarBase, miRNet, miRDB, and TargetScan. In addition, network diagrams were built using Cytoscape software. As competing endogenous RNAs (ceRNAs) are endogenous transcripts that compete for the binding of microRNAs (miRNAs) by using shared miRNA recognition elements, they are involved in creating widespread regulatory networks. Therefore, the ceRNA regulatory networks of TERT were also investigated in this study. Interestingly, we found that the three genes PABPC1, SLC7A11, and TP53 were present in both TERT interaction networks and ceRNAs target genes. It was predicted that TERT might play nontelomeric roles in the generation or development of some rare diseases, such as Rift Valley fever and dyscalculia. Thus, our data will help to decipher the interaction networks of TERT and reveal the unknown functions of telomerase in cancer and aging-related diseases.

Pulmonary microRNA profiles identify involvement of Creb1 and Sec14l3 in bronchial epithelial changes in allergic asthma

Asthma is highly prevalent, but current therapies cannot influence the chronic course of the disease. It is thus important to understand underlying early molecular events. In this study, we aimed to use microRNAs (miRNAs) - which are critical regulators of signaling cascades - to identify so far uncharacterized asthma pathogenesis pathways. Therefore, deregulation of miRNAs was assessed in whole lungs from mice with ovalbumin (OVA)-induced allergic airway inflammation (AAI). In silico predicted target genes were confirmed in reporter assays and in house-dust-mite (HDM) induced AAI and primary human bronchial epithelial cells (NHBE) cultured at the air-liquid interface. We identified and validated the transcription factor cAMP-responsive element binding protein (Creb1) and its transcriptional co-activators (Crtc1-3) as targets of miR-17, miR-144, and miR-21. Sec14-like 3 (Sec14l3) - a putative target of Creb1 - was down-regulated in both asthma models and in NHBE cells upon IL13 treatment, while it’s expression correlated with ciliated cell development and decreased along with increasing goblet cell metaplasia. Finally, we propose that Creb1/Crtc1-3 and Sec14l3 could be important for early responses of the bronchial epithelium to Th2-stimuli. This study shows that miRNA profiles can be used to identify novel targets that would be overlooked in mRNA based strategies.

Chromosome 19q13 disruption alters expressions of CYP2A7, MIA and MIA-RAB4B lncRNA and contributes to FAP-like phenotype in APC mutation-negative familial colorectal cancer patients

Familial adenomatous polyposis (FAP) is an autosomal-dominantly inherited form of colorectal cancer (CRC) caused by mutation in the adenomatous polyposis coli (APC) gene. Our ability to exhaustively screen for APC mutations identify microsatellite-stable and APC-mutation negative familial CRC patients, enabling us to search for novel genes. We performed genome-wide scan on two affected siblings of one family and 88 ethnicity- and gender-matched healthy controls to identify deletions shared by the siblings. Combined loss of heterozygosity, copy number and allelic-specific copy number analysis uncovered 5 shared deletions. Long-range polymerase chain reaction (PCR) confirmed chromosome 19q13 deletion, which was subsequently found in one other family. The 32 kb deleted region harbors the CYP2A7 gene and was enriched with enhancer, repressor and insulator sites. The wildtype allele was lost in the polyps of the proband. Further, real-time RT-PCR assays showed that expressions of MIA and MIA-RAB4B located 35 kb upstream of the deletion, were up-regulated in the polyps compared to the matched mucosa of the proband. MIA-RAB4B, the read-through long non-coding RNA (lncRNA), RAB4B, PIM2 and TAOK1 share common binding site of a microRNA, miR-24, in their 3'UTRs. PIM2 and TAOK1, two target oncogenes of miR-24, were co-ordinately up-regulated with MIA-RAB4B in the polyps, suggesting that MIA-RAB4B could function as competitive endogenous RNA to titrate miR-24 away from its other targets. The data suggest that the 19.13 deletion disrupted chromatin boundary, leading to altered expression of several genes and lncRNA, could contribute to colorectal cancer via novel genetic and epigenetic mechanisms.

Circular RNA 0000096 affects cell growth and migration in gastric cancer

Background:

Circular RNAs (circRNAs) are a class of non-coding RNAs broadly expressed in cells of various species. Their role in cancers, especially in gastric cancer, is poorly understood.

Methods:

Circular RNA 0000096 (hsa_circ_0000096) levels in 101 paired gastric cancer tissues and adjacent non-tumorous tissues from patients with gastric cancer were detected by real-time quantitative reverse transcription-polymerase chain reaction. A receiver operating characteristic curve was generated to evaluate the diagnostic value of hsa_circ_0000096. RNA interference was used to manipulate the expression of hsa_circ_0000096. Its biological effects were evaluated by flow cytometry, real-time cell analysis, a wound scratch assay, western blot analysis and xenograft models.

Results:

Hsa_circ_0000096 was found to be significantly downregulated in gastric cancer tissues and gastric cancer cell lines compared with paired adjacent non-tumorous tissues and normal gastric epithelial cells (P<0.001). Moreover, knockdown of hsa_circ_0000096 significantly inhibited cell proliferation and migration in vitro and in vivo. The results of both immunohistochemical and western blot analyses showed that the protein levels of cyclin D1, cyclin-dependent kinase 6 (CDK6), matrix metalloproteinase-2 and MMP-9 were significantly reduced in vitro and in vivo. A gastric cancer xenograft nude mouse model indicated that Ki67 and VEGF were reduced in a dose-dependent manner following knockdown of hsa_circ_0000096. However, the expression of E-cadherin increased.

Conclusions:

Hsa_circ_0000096 may be used as a potential novel biomarker for gastric cancer. It affects gastric cancer cell growth and migration by regulating cyclin D1, CDK6, MMP-2 and MMP-9.

CCR2 3′UTR functions as a competing endogenous RNA to inhibit breast cancer metastasis

Diverse RNA transcripts acting as competing endogenous RNAs (ceRNAs) can co-regulate each other's expression by competing for shared microRNAs. CCR2 protein, the receptor of CCL2, is implicated in cancer progression. However, our results showed that higher CCR2 mRNA level was remarkably associated with prolonged survival of breast cancer patients. The conflicting results prompt us to study the non-coding function of CCR2 mRNA. We indicated that CCR2 3′UTR inhibited MDA-MB-231 and MCF-7 cells metastasis by repressing EMT in vitro and suppressed breast cancer metastasis in vivo. Mechanistically, CCR2 3′UTR modulated RhoGAP protein STARD13 expression via acting as a STARD13 ceRNA in a microRNA-dependent and protein coding-independent manner. CCR2 3′UTR blocked the activation of RhoA-ROCK1 pathway which is the downstream effector of STARD13 and thus decreased the phosphorylation level of MLC and formation of F-actin. Additionally, the function of CCR2 3′UTR was dependent on STARD13 expression. In conclusion, our results confirmed that CCR2 3′UTR acts as a metastasis suppressor by acting as a ceRNA for STARD13 and thus inhibiting RhoA→ROCK1→MLC→F-actin pathway in breast cancer cells.

ZNF148 modulates TOP2A expression and cell proliferation via ceRNA regulatory mechanism in colorectal cancer

BACKGROUND

Competing endogenous RNA (ceRNA) regulation is a novel hypothesized mechanism that states RNA molecules share common target microRNAs (miRNAs) and may competitively combine into the same miRNA pool.

METHODS

Zinc finger protein 148 (ZNF148) and TOP2A expression were analyzed in 742 colorectal cancer (CRC) tissues using immunohistochemistry (IHC). ZNF148 mRNA, TOP2A mRNA, miR101, miR144, miR335, and miR365 expression were estimated in 53 fresh frozen CRC tissues by reverse transcription polymerase chain reaction. Mechanisms underpinning ceRNA were examined using bioinformatics, correlation analysis, RNA interference, gene over-expression, and luciferase assays.

RESULTS

Protein levels of ZNF148 and TOP2A detected by IHC positively correlated (Spearman correlation coefficient [rs] = 0.431, P < 0.001); mRNA levels of ZNF148 and TOP2A also positively correlated (r = 0.591, P < 0.001). Bioinformatics analysis demonstrated that ZNF148 and TOP2A mRNA had 13 common target miRNAs, including miR101, miR144, miR335, and miR365. Correlation analysis demonstrated that levels of ZNF148 mRNA were negatively associated with levels of miR144, miR335, and miR365. Knockdown and overexpression tests showed that ZNF148 mRNA and TOP2A mRNA regulated each other in HCT116 cells, respectively, but not in Dicer-deficient HCT116 cells. Luciferase assays demonstrated that ZNF148 and TOP2A regulated each other through 3'UTR. Overexpression of ZNF148 mRNA and TOP2A mRNA caused significant downregulation of miR101, miR144, miR335, and miR365 in the HCT116 cells. We also found that knockdown of ZNF148 and TOP2A significantly promoted cell growth, and overexpression of ZNF148 and TOP2A inhibited cell proliferation, which was abrogated in Dicer-deficient HCT116 cells.

CONCLUSION

ZNF148 and TOP2A regulate each other through ceRNA regulatory mechanism in CRC, which has biological effects on cell proliferation.

Vascular endothelial growth factor suppresses TNFSF15 production in endothelial cells by stimulating miR-31 and miR-20a expression via activation of Akt and Erk signals

Tumor necrosis factor superfamily‐15 (TNFSF15; VEGI; TL1A) is a negative modulator of angiogenesis for blood vessel homeostasis and is produced by endothelial cells in a mature vasculature. It is known to be downregulated by vascular endothelial growth factor (VEGF), a major regulator of neovascularization but the mechanism of this interaction is unclear. Here we report that VEGF is able to stimulate the production of two microRNAs, miR‐20a and miR‐31, which directly target the 3′‐UTR of TNFSF15. Additionally, we show that two VEGF‐stimulated cell growth signals, Erk and Akt, are responsible for promoting the expression of miR‐20a and miR‐31. Treatment of human umbilical vein endothelial cells (HUVECs) with Akt inhibitor LY294002 results in diminished miR‐20a and miR‐31 production, while Erk inhibitor U0126 prevented VEGF‐stimulated expression of miR‐20a but not that of miR‐31. Furthermore, inactivation of either Erk or Akt signals restores TNFSF15 gene expression. In an angiogenesis assay, elevated miR‐20a or miR‐31 levels in HUVECs leads to enhancement of capillary‐like tubule formation in vitro, whereas lowered miR‐20a and miR‐31 levels results in an inhibition. These findings are consistent with the view that miR‐20a and miR‐31 mediate VEGF‐induced downregulation of TNFSF15. Targeting these microRNA molecules may therefore provide an effective approach to inhibit angiogenesis.

STARD13 promotes hepatocellular carcinoma apoptosis by acting as a ceRNA for Fas

OBJECTIVES

To study the roles of STARD13 in cellular apoptosis of hepatocellular carcinoma (HCC).

RESULTS

Quantitative real-time PCR and immunohistochemistry analyses showed that the expression levels of STARD13 and Fas were lower in clinical HCC tissues than in normal tissues and were positively correlated, which is consistent with the results analyzed by The Cancer Genome Atlas (TCGA) data. Patients with higher STARD13 or Fas expression levels had longer overall survival. Additionally, STARD13 3'-UTR enhanced cellular apoptosis and the 3'-UTRs of STARD13 and Fas were predicted to harbor nine similar miRNA binding sites. And STARD13 3'-UTR promoted Fas expression in a 3'-UTR- and miRNA-dependent way and increased the sensitivity of HCC cells to chemotherapy. Importantly, the coding sequence of STARD13 did not increase Fas expression.

CONCLUSIONS

STARD13 3'-UTR promotes HCC apoptosis through acting as a ceRNA for Fas.

A panel of four genes accurately differentiates benign from malignant thyroid nodules

Background

Clinicians are confronted with an increasing number of patients with thyroid nodules. Reliable preoperative diagnosis of thyroid nodules remains a challenge because of inconclusive cytological examination of fine-needle aspiration biopsies. Although molecular analysis of thyroid tissue has shown promise as a diagnostic tool in recent years, it has not been successfully applied in routine clinical use, particularly in Chinese patients.

Methods

Whole-transcriptome sequencing of 19 primary papillary thyroid cancer (PTC) samples and matched adjacent normal thyroid tissue (NT) samples were performed. Bioinformatics analysis was carried out to identify candidate diagnostic genes. Then, RT-qPCR was performed to evaluate these candidate genes, and four genes were finally selected. Based on these four genes, diagnostic algorithm was developed (training set: 100 thyroid cancer (TC) and 65 benign thyroid lesions (BTL)) and validated (independent set: 123 TC and 81 BTL) using the support vector machine (SVM) approach.

Results

We discovered four genes, namely fibronectin 1 (FN1), gamma-aminobutyric acid type A receptor beta 2 subunit (GABRB2), neuronal guanine nucleotide exchange factor (NGEF) and high-mobility group AT-hook 2 (HMGA2). A SVM model with these four genes performed with 97.0 % sensitivity, 93.8 % specificity, 96.0 % positive predictive value (PPV), and 95.3 % negative predictive value (NPV) in training set. For additional independent validation, it also showed good performance (92.7 % sensitivity, 90.1 % specificity, 93.4 % PPV, and 89.0 % NPV).

Conclusions

Our diagnostic panel can accurately distinguish benign from malignant thyroid nodules using a simple and affordable method, which may have daily clinical application in the near future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0447-3) contains supplementary material, which is available to authorized users.

Lin28b Regulates Fetal Regulatory T Cell Differentiation through Modulation of TGF-β Signaling

Immune tolerance between the fetus and mother represents an active process by which the developing fetus must not mount immune responses to noninherited Ags on chimeric maternal cells that reside in fetal tissue. This is, in part, mediated by the suppressive influence of CD4⁺FOXP3⁺CD25⁺ regulatory T cells (Tregs). Fetal secondary lymphoid organs have an increased frequency of Tregs and, as compared with adult T cells, fetal naive CD4⁺ T cells exhibit a strong predisposition to differentiate into Tregs when stimulated. This effect is mediated by the TCR and TGF-β pathways, and fetal T cells show significantly increased Treg differentiation in response to anti-CD3 and TGF-β stimulation. Naive fetal T cells also exhibit increased signaling through the TGF-β pathway, with these cells demonstrating increased expression of the signaling mediators TGF-βRI, TGF-βRIII, and SMAD2, and higher levels of SMAD2/SMAD3 phosphorylation. Increased fetal Treg differentiation is mediated by the RNA-binding protein Lin28b, which is overexpressed in fetal T cells as compared with adult cells. When Lin28b expression is decreased in naive fetal T cells, they exhibit decreased Treg differentiation that is associated with decreased TGF-β signaling and lowered expression of TGF-βRI, TGF-βRIII, and SMAD2. Lin28b regulates the maturation of let-7 microRNAs, and these TGF-β signaling mediators are let-7 targets. We hypothesize that loss of Lin28b expression in fetal T cells leads to increased mature let-7, which causes decreased expression of TGF-βRI, TGF-βRIII, and SMAD2 proteins. A reduction in TGF-β signaling leads to reduced Treg numbers.

The role of microRNA-155/liver X receptor pathway in experimental and idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is progressive and rapidly fatal. Improved understanding of pathogenesis is required to prosper novel therapeutics. Epigenetic changes contribute to IPF; therefore, microRNAs may reveal novel pathogenic pathways.

Objectives

We sought to determine the regulatory role of microRNA (miR)-155 in the profibrotic function of murine lung macrophages and fibroblasts, IPF lung fibroblasts, and its contribution to experimental pulmonary fibrosis.

Methods

Bleomycin-induced lung fibrosis in wild-type and miR-155^−/− mice was analyzed by histology, collagen, and profibrotic gene expression. Mechanisms were identified by in silico and molecular approaches and validated in mouse lung fibroblasts and macrophages, and in IPF lung fibroblasts, using loss-and-gain of function assays, and in vivo using specific inhibitors.

Results

miR-155^−/− mice developed exacerbated lung fibrosis, increased collagen deposition, collagen 1 and 3 mRNA expression, TGF-β production, and activation of alternatively activated macrophages, contributed by deregulation of the miR-155 target gene the liver X receptor (LXR)α in lung fibroblasts and macrophages. Inhibition of LXRα in experimental lung fibrosis and in IPF lung fibroblasts reduced the exacerbated fibrotic response. Similarly, enforced expression of miR-155 reduced the profibrotic phenotype of IPF and miR-155^−/− fibroblasts.

Conclusions

We describe herein a molecular pathway comprising miR-155 and its epigenetic LXRα target that when deregulated enables pathogenic pulmonary fibrosis. Manipulation of the miR-155/LXR pathway may have therapeutic potential for IPF.

The lncRNA H19 promotes epithelial to mesenchymal transition by functioning as miRNA sponges in colorectal cancer

Recently, the long non-coding RNA (lncRNA) H19 has been identified as an oncogenic gene in multiple cancer types and elevated expression of H19 was tightly linked to tumorigenesis and cancer progression. However, the molecular basis for this observation has not been characterized in colorectal cancer (CRC) especially during epithelial to mesenchymal transition (EMT) progression. In our studies, H19 was characterized as a novel regulator of EMT in CRC. We found that H19 was highly expressed in mesenchymal-like cancer cells and primary CRC tissues. Stable expression of H19 significantly promotes EMT progression and accelerates in vivo and in vitro tumor growth. Furthermore, by using bioinformatics study and RNA immunoprecipitation combined with luciferase reporter assays, we demonstrated that H19 functioned as a competing endogenous RNA (ceRNA) for miR-138 and miR-200a, antagonized their functions and led to the de-repression of their endogenous targets Vimentin, ZEB1, and ZEB2, all of which were core marker genes for mesenchymal cells. Taken together, these observations imply that the lncRNA H19 modulated the expression of multiple genes involved in EMT by acting as a competing endogenous RNA, which may build up the missing link between the regulatory miRNA network and EMT progression.

The long non-coding RNA, SNHG6-003, functions as a competing endogenous RNA to promote the progression of hepatocellular carcinoma

The expression of long non-coding RNAs (lncRNAs) is dysregulated in hepatocellular carcinoma (HCC). However, the functions and contributions of lncRNAs remain largely unknown. Here, we identified a critical role of SNHG6-003 in HCC. We found that five SNHG6 transcripts were differentially expressed in HCC tissues while only the SNHG6-003 had an oncogenic function. Ectopic expression of SNHG6-003 in HCC cells promoted cell proliferation and induced drug resistance, whereas SNHG6-003 knockdown promoted apoptosis. Moreover, SNHG6-003 functioned as a competitive endogenous RNA (ceRNA), effectively becoming sponge for miR-26a/b and thereby modulating the expression of transforming growth factor-β-activated kinase 1 (TAK1). Importantly, expression analysis revealed that both SNHG6-003 and TAK1 were upregulated in human cancers, exhibiting a co-expression pattern. In HCC patients, high expression of SNHG6-003 closely correlated with tumor progression and shorter survival. Thus, targeting the ceRNA network involving SNHG6-003 may be used as a treatment strategy against HCC.

Detection of high mobility group A2 specific mRNA in the plasma of patients affected by epithelial ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy and the high mortality rate is associated with advanced-stage disease at the time of the diagnosis. In order to find new tools to make diagnosis of Epithelial Ovarian Cancer (EOC) at early stages we have analyzed the presence of specific HMGA2 mRNA in the plasma of patients affected by this neoplasm. HMGA2 overexpression represents a feature of several malignances including ovarian carcinomas. Notably, we detected HMGA2 specific mRNA in the plasma of 40 out 47 patients with EOC, but not in the plasma of healthy donors. All cases found positive for HMGA2 mRNA in the plasma showed HMGA2 protein expression in EOC tissues.

Therefore, on the basis of these results, the analysis of circulating HMGA2 specific mRNA might be considered a very promising tool for the early diagnosis of EOC.

Downregulated miR-31 level associates with poor prognosis of gastric cancer and its restoration suppresses tumor cell malignant phenotypes by inhibiting E2F2

The miRNA microarray analysis showed that miR-31 was reduced in gastric cancer. This study further assessed miR-31 expression and role of miR-31 in gastric cancer tissues and cell lines. The data showed that miR-31 expression was down-regulated in 40 cases of gastric cancer tissues compared to the adjacent normal tissues, and low expression of miR-31 was associated with poor tumor differentiation, lymph node metastasis, advanced T stage and worse overall survival of gastric cancer patients. Ectopic expression of miR-31 reduced tumor cell viability, enhanced apoptosis, arrested tumor cells at G1 transition, and reduced tumor cell migration and invasion in SGC-7901 and MGC-803 gastric cell lines in vitro. Enforced expression of miR-31 also inhibited growth of engrafted tumors in vivo. Luciferase reporter assays and western blot revealed that E2F2 is the direct target of miR-31. E2F2 expression was upregulated in gastric cancer tissues, and inversely associated with miR-31 levels, while knockdown of E2F2 expression mimicked miR-31 anti-tumor activity in gastric cancer cells, but the ectopic expression of E2F2 rescued the miR-31-mediated inhibition in gastric cell lines. Taken together, these results demonstrated that miR-31 acts as a crucial tumor suppressive activity by inhibiting E2F2s expression. Thus, miR-31 might be a candidate therapeutic target for gastric cancer patients.

The long noncoding RNA NRF regulates programmed necrosis and myocardial injury during ischemia and reperfusion by targeting miR-873

Emerging evidences suggest that necrosis is programmed and is one of the main forms of cell death in the pathological process in cardiac diseases. Long noncoding RNAs (lncRNAs) are emerging as new players in gene regulation. However, it is not yet clear whether lncRNAs can regulate necrosis in cardiomyocytes. Here, we report that a long noncoding RNA, named necrosis-related factor (NRF), regulates cardiomyocytes necrosis by targeting miR-873 and RIPK1 (receptor-interacting serine/threonine-protein kinase 1)/RIPK3 (receptor-interacting serine/threonine-protein kinase 3). Our results show that RIPK1 and RIPK3 participate in H2O2-induced cardiomyocytes necrosis. miR-873 suppresses the translation of RIPK1/RIPK3 and inhibits RIPK1/RIPK3-mediated necrotic cell death in cardiomyocytes. miR-873 reduces myocardial infarct size upon ischemia/reperfusion (I/R) injury in the animal model. In exploring the molecular mechanism by which miR-873 expression is regulated, we identify NRF as an endogenous sponge RNA and repress miR-873 expression. NRF directly binds to miR-873 and regulates RIPK1/RIPK3 expression and necrosis. Knockdown of NRF antagonizes necrosis in cardiomyocytes and reduces necrosis and myocardial infarction upon I/R injury. Further, we identify that p53 transcriptionally activates NRF expression. P53 regulates cardiomyocytes necrosis and myocardial I/R injury through NRF and miR-873.Our results identify a novel mechanism involving NRF and miR-873 in regulating programmed necrosis in the heart and suggest a potential therapeutic avenue for cardiovascular diseases.

Long Non-Coding RNA CCAT1 Acts as a Competing Endogenous RNA to Regulate Cell Growth and Differentiation in Acute Myeloid Leukemia

Long non-coding RNAs (lncRNAs) are involved in multiple cellular events, as well as in tumorigenesis. Colon cancer-associated transcript-1 (CCAT1) gene encodes an lncRNA whose over-activation was observed in an expanding list of primary human solid tumors and tumor cell lines, however its biological roles in acute myeloid leukaemia (AML) has not been reported yet at present. In this study, the aberrant upregulation of CCAT1 was detected in French-American-British M4 and M5 subtypes of adult AML patients. By gain- and loss-of-function analysis, we determined that CCAT1 repressed monocytic differentiation and promoted cell growth of HL-60 by sequestering tumor suppressive miR-155. Accordingly, a significant decrease in miR-155 level was detected in AML patients. Re-introduction of miR-155 into HL-60 cells restored monocytic maturation and repressed cell proliferation. Furthermore, CCAT1 could up-regulated c-Myc via its competing endogenous RNA (ceRNA) activity on miR-155. In conclusion, these results revealed new mechanism of lncRNA CCAT1 in AML development, and suggested that the manipulation of CCAT1 expression could serve as a potential strategy in AML therapy.

ANG Promotes Proliferation and Invasion of the Cell of Lung Squamous Carcinoma by Directly Up-Regulating HMGA2

Objective: To determine the mechanism of Angiogenin(ANG) function involved in the carcinogenesis of lung squamous cell carcinoma.

Methods: 12 patients' normal tissue and cancerous tissue were collected. ANG expression in the squamous cell carcinoma of the lung was evaluated by qRT-PCR and western-blot. The regulation of ANG on proliferation, migration, invasion, and apoptosis of SK-MES-1 cells were analyzed by Cell Counting Kit-8, Transwell migration chamber, Transwell invasion chamber, and Annexin V-FITC assay, respectively. PCR array was utilized for screening potential target genes of ANG. Chromatin immunoprecipitation(ChIP) assays and luciferase assay were adopted for investigation of ANG's direct regulation on HMGA2.

Results: ANG expression is increased in the squamous cell carcinoma of the lung tissue. In vitro experiments results indicated that overexpression of ANG promotes proliferation and invasion capability of SK-MES-1 cells. The candidate proliferation, migration, and invasion related ANG target gene found was HMGA2, expression levels of which were also enhanced in lung squamous cell carcinoma tissue. The direct regulation of ANG on HMGA2 was verified by ChIP and luciferase assay results. Furthermore, down-regulating HMGA2 significantly alleviated the suppression effects of ANG on proliferation, migration, and invasion of SK-MES-1 cells.

Conclusions: Our data illustrated the mechanisms that ANG promoted the cell of SQCLC proliferation, migration, and invasion capacity via directly up-regulating HMGA2.

SREBP-1c/MicroRNA 33b Genomic Loci Control Adipocyte Differentiation

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promoting in vitro adipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precluding in vivo assessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along with SREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease.

Microarray expression profiling of dysregulated long non-coding RNAs in Hirschsprung's disease reveals their potential role in molecular diagnosis

BACKGROUND

Hirschsprung's disease (HSCR) is one of the common digestive disorders in the new born. Long non-coding RNAs (lncRNAs) play an important role in various biological processes. However, knowledge on lncRNAs in HSCR is limited.

METHODS

The expression profile of lncRNAs in HSCR was obtained using microarray. A total of 2078 differentially expressed lncRNAs were detected by microarray in HSCR tissues compared with matched normal colon tissues (fold change ≥2, p < 0.05). Candidate biomarkers were selected from these differentially expressed lncRNAs based on artificial criterion (raw signal intensity ≥50; fold change ≥8) and then validated in 80 pairs of HSCR and normal tissues using quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the computational analysis was used to evaluate the lncRNA-microRNA and lncRNA-protein relationships.

KEY RESULTS

A panel of 5-lncRNAs was identified to distinguish HSCR from normal tissues with remarkable sensitivity and specificity. The area under the receiver operating characteristic curve (AUC) for HSCR identification in the validation set was 0.875. The bioinformatics analysis reveals that these dysregulated lncRNAs are mainly involved in RNA-protein relationships, including RNA splicing, binding, transport, processing, and localization.

CONCLUSIONS & INFERENCES

Our results are the first to report the expression profile of dysregulated lncRNAs in HSCR and infer that lncRNAs may serve as novel diagnostic biomarkers for HSCR.

Overexpression of HMGA2 promotes tongue cancer metastasis through EMT pathway

BACKGROUND

Metastasis to long distance organs is the main reason leading to morality of tongue squamous cell carcinoma (TSCC); however, the molecular mechanisms are still unknown. High mobility group AT-hook 2 (HMGA2) is highly expressed in multiple metastatic carcinomas, in which it contributes to cancer progression, metastasis and poor prognosis by upregulating Snail expression and inducing epithelial mesenchymal transition (EMT). This study focuses on investigating the role and mechanism of regulation of HMGA2 in the metastasis of TSCC.

METHODS

HMGA2 mRNA and protein expression were examined in TSCC specimens by quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry (IHC). Western blotting, IHC and immunofluorescence were also used to measure the expression and localization of EMT marker E-Cadherin and Vimentin both in TSCC cells and tissues. Knockdown assay was performed in vitro in TSCC cell lines using small interfering RNAs and the functional assay was carried out to determine the role of HMGA2 in TSCC cell migration and invasion.

RESULTS

TSCC mRNA and protein expression were significantly up-regulated in tumor tissues when compared to adjacent non-tumor tissues, and the overexpression of HMGA2 was closely correlated with lymph nodes metastasis. Clinicopathological analysis indicated that HMGA2 expression was associated with clinical stage (P = 0.001), lymph node metastasis (P = 0.000), histological differentiation (P = 0.002) and survival (P = 0.000). Silencing the HMGA2 expression in Cal27 and UM1 resulted in the inhibition of cell migration and invasion, meanwhile down-regulation of HMGA2 impaired the phenotype of EMT in TSCC cell lines and tissues. The Multivariate survival analysis indicates that HMGA2 can be an independent prognosis biomarker in TSCC.

CONCLUSION

Our findings demonstrate that HMGA2 promotes TSCC invasion and metastasis; additionally, HMGA2 is an independent prognostic factor which implied that HMGA2 can be a biomarker both for prognosis and therapeutic target of TSCC.

Let-7c down-regulation in Helicobacter pylori-related gastric carcinogenesis

Aberrant let-7c microRNA (miRNA) expression has been observed in Helicobacter pylori-related gastric cancer (GC) but fragmentary information is available on the let-7c dysregulation occurring with each phenotypic change involved in gastric carcinogenesis. Let-7c expression was assessed (qRT-PCR) in a series of 175 gastric biopsy samples representative of the whole spectrum of phenotypic changes involved in H. pylori-related gastric oncogenesis including: i) normal gastric mucosa, as obtained from dyspeptic controls (40 biopsy samples); ii) non-atrophic gastritis (40 samples); iii) atrophic-metaplastic gastritis (35 samples); iv) intra-epithelial neoplasia (30 samples); v) GC (30 samples). Let-7c expression was also tested in 20 biopsy samples obtained from 10 patients before and after H. pylori eradication therapy (median follow-up: 10 weeks; range: 7-14). The results obtained were further validated by in situ hybridization on multiple tissue specimens obtained from 5 surgically treated H. pylori-related GCs. The study also included 40 oxyntic biopsy samples obtained from serologically/histologically confirmed autoimmune gastritis (AIG: 20 corpus-restricted, non-atrophic; 20 corpus-restricted, atrophic-metaplastic). Let-7c expression dropped from non-atrophic gastritis to atrophic-metaplastic gastritis, intra-epithelial neoplasia, and invasive GC (p<0.001). It rose again significantly following H. pylori eradication (p=0.009). As in the H. pylori model, AIG also featured a significant let-7c down-regulation (p<0.001). The earliest phases of the two pathways to gastric oncogenesis (H. pylori-environmental and autoimmune host-related) are characterized by similar let-7c dysregulations. In H. pylori infection, let-7c down-regulation regresses after the bacterium's eradication, while it progresses significantly with the increasing severity of the histological lesions.

Identification of potential COPD genes based on multi-omics data at the functional level

A novel systematic approach MMMG (Methylation–MicroRNA–MRNA–GO) to identify potential COPD genes and their classifying performance evaluation.

Let-7a suppresses glioma cell proliferation and invasion through TGF-β/Smad3 signaling pathway by targeting HMGA2

It has been shown that let-7a was associated with the tumorigenesis of glioma. Our study was designed to infer how let-7a targets high-mobility AT-hook 2 (HMGA2) and suppresses glioma cell proliferation, invasion, and migration. Glioma tissues from 60 glioma patients and 10 normal brain tissues were collected in this study. Real-time quantitative reverse transcription-PCR (qRT-PCR) and in situ hybridization were used to detect the expression levels of let-7a in tissues and cells. The HMGA2 and the proteins related to transforming growth factor-beta (TGF-β)/Smad3 signaling pathway were measured by immunohistochemistry and western blot. Glioma U87 cells were transfected with either let-7a mimics, HMGA2 small interfering RNA (siRNA), let-7a mimics + HMGA2, HMGA2, or scramble. A cell counting kit-8 (CCK-8) assay was used to detect and compare the difference among various transfection groups. Glioma tumor xenograft models on mice were built to evaluate the effects of let-7a and HMGA2 siRNA on glioma tumors in vivo. The expression level of let-7a significantly downregulated in glioma tissues, while the HMGA2 positive expression rate notably increased compared with those in normal brain tissues (all P < 0.05). Moreover, the expression levels of let-7a and HMGA2 were correlated with glioma grades (all P < 0.05). The proliferation of U87 cells transfected with let-7a mimics or HMGA2 siRNA was significantly inhibited in comparison to the blank control group and the apoptosis rates of U87 cells transfected with let-7a mimics or HMGA2 siRNA were significantly higher than those in the blank control group (all P < 0.05). Let-7a or HMGA2 siRNA could remarkably attenuate the invasion and migration ability of glioma cells (all P < 0.05). Apart from that, over-expressed exogenous HMGA2 could reverse the inhibition of glioma cell metastasis and proliferation induced by let-7a. As suggested by immunohistochemistry and western blot, the expression levels of TGF-β1 and p-Smad3 significantly decreased compared with the blank or scramble group (all P < 0.05). Thus, let-7a and HMGA2 siRNA could effectively suppress the growth of tumors in glioma xenograft models. Let-7a may suppress the proliferation and invasion of glioma cells through mediating TGF-β/Smad3 signaling pathway by targeting HMGA2.

Integration of Signaling Pathways with the Epigenetic Machinery in the Maintenance of Stem Cells

Stem cells balance their self-renewal and differentiation potential by integrating environmental signals with the transcriptional regulatory network. The maintenance of cell identity and/or cell lineage commitment relies on the interplay of multiple factors including signaling pathways, transcription factors, and the epigenetic machinery. These regulatory modules are strongly interconnected and they influence the pattern of gene expression of stem cells, thus guiding their cellular fate. Embryonic stem cells (ESCs) represent an invaluable tool to study this interplay, being able to indefinitely self-renew and to differentiate towards all three embryonic germ layers in response to developmental cues. In this review, we highlight those mechanisms of signaling to chromatin, which regulate chromatin modifying enzymes, histone modifications, and nucleosome occupancy. In addition, we report the molecular mechanisms through which signaling pathways affect both the epigenetic and the transcriptional state of ESCs, thereby influencing their cell identity. We propose that the dynamic nature of oscillating signaling and the different regulatory network topologies through which those signals are encoded determine specific gene expression programs, leading to the fluctuation of ESCs among multiple pluripotent states or to the establishment of the necessary conditions to exit pluripotency.

Foxo3 activity promoted by non-coding effects of circular RNA and Foxo3 pseudogene in the inhibition of tumor growth and angiogenesis

It has recently been shown that the upregulation of a pseudogene specific to a protein-coding gene could function as a sponge to bind multiple potential targeting microRNAs (miRNAs), resulting in increased gene expression. Similarly, it was recently demonstrated that circular RNAs can function as sponges for miRNAs, and could upregulate expression of mRNAs containing an identical sequence. Furthermore, some mRNAs are now known to not only translate protein, but also function to sponge miRNA binding, facilitating gene expression. Collectively, these appear to be effective mechanisms to ensure gene expression and protein activity. Here we show that expression of a member of the forkhead family of transcription factors, Foxo3, is regulated by the Foxo3 pseudogene (Foxo3P), and Foxo3 circular RNA, both of which bind to eight miRNAs. We found that the ectopic expression of the Foxo3P, Foxo3 circular RNA and Foxo3 mRNA could all suppress tumor growth and cancer cell proliferation and survival. Our results showed that at least three mechanisms are used to ensure protein translation of Foxo3, which reflects an essential role of Foxo3 and its corresponding non-coding RNAs.

A functional polymorphism in CSF1R gene is a novel susceptibility marker for lung cancer among never-smoking females

INTRODUCTION

It has been estimated that the proportion of never-smokers among females with lung cancer is 53% worldwide and 75% in Korea. We conducted a two-stage study to identify genetic factors responsible for lung cancer susceptibility in female never-smokers.

MATERIALS AND METHODS

In a discovery set, 1969 potentially functional single nucleotide polymorphisms (SNPs) of 1151 genes, which were related to cancer development and progression, were evaluated using the Affymetrix custom-made GeneChip in 181 female never-smokers with lung cancer and 179 controls. A replication study was performed on an independent cohort of 596 cases and 1194 healthy controls.

RESULTS

Sixteen SNPs with p < 0.05 for genotype distribution in the discovery set were enrolled in the replication study. Among 16 SNPs, three SNPs (colony-stimulating factor 1 receptor [CSF1R] rs10079250A>G, tumor protein p63 [TP63] rs7631358G>A, and corepressor interacting with RBPJ 1 [CIR1] rs13009079T>C) were found to be significantly associated with lung cancer in the same direction as the discovery set. Homology-based model for CSF1R indicated that the rs10079250A>G leads to increased positive charge of CSF-binding region of CSF1R, thereby increasing the chance of binding between CSF and CSF1R. In addition, this SNP was found to increase the phosphorylation of a mitogen-activated protein kinase, JNK.

CONCLUSIONS

Our results suggest that the three SNPs, particularly CSF1R rs10079250, may contribute to lung cancer susceptibility in never-smoking females.

Carbonic Anhydrase 9 mRNA/microRNA34a Interplay in Hypoxic Human Mammospheres

The hypoxic environment is a crucial component of the cancer stem cell niche and it is capable of eliciting stem cell features in cancer cells. We previously reported that SNAI2 up-regulates the expression of Carbonic Anhydrase iso-enzyme 9 (CA9) in hypoxic MCF7 cells. Here we show that SNAI2 down-regulates miR34a expression in hypoxic MCF7 cell-derived mammospheres. Next, we report on the capability of miR34a to decrease CA9 mRNA stability and CA9 protein expression. We also convey that the over-expression of cloned CA9-mRNA-3'UTR increases the mRNA half-life and protein levels of two miR34a targets JAGGED1 and NOTCH3. The data here reported shows that the SNAI2-dependent down-regulation of miR34a substantially contributes to the post-transcriptional up-regulation of CA9, and that CA9-mRNA-3'UTR acts as an endogenous microRNA sponge. We conclude that CA9/miR34 interplay shares in the hypoxic regulation of mammospheres and therefore, may play a relevant role in the hypoxic breast cancer stem cell niche.

Upregulation of miR-497 induces hepatic insulin resistance in E3 rats with HFD-MetS by targeting insulin receptor

OBJECTIVE

The study aims to find regulatory microRNA(s) responsible for down-regulated insulin receptor (InsR) in the liver of HFD-MetS E3 rats with insulin resistance.

METHODS

Firstly, hepatic insulin resistance in HFD-MetS E3 rats was evaluated by RT-qPCR, western blotting, immunohistochemistry and PAS staining. Secondly, the candidate miRNAs targeting rat InsR were predicted through online softwares and detected in the liver of HFD-MetS E3 rats with insulin resistance. Then, the expression of InsR, phosphorylated IRS-1 (pIRS-1) at Tyr632, phosphorylated AKTs (pAKTs) at Ser473 and Thr308, phosphorylated GSK-3β (p GSK-3β) at Ser9, phosphorylated GS (pGS) at Ser641 and the glycogen content were detected in CBRH-7919 cells treated with 100 nM insulin for different time periods by western blotting or PAS staining respectively, after transient transfection with miR-497 mimics or inhibitors for 24 h. Lastly, the relation between miR-497 and InsR was further determined using dual luciferase reporter assay.

RESULTS

Elevated miR-497 was negatively related with down-regulated InsR in the liver of HFD-MetS E3 rats with insulin resistance. Comparing with the mNC group, glycogen content and the expression of InsR, pIRS-1 (Tyr632), pAKTs (Ser473 and Thr308) and pGSK-3β (Ser9) decreased significantly in CBRH-7919 cells, while pGS (Ser641) increased significantly, after transient transfection with miR-497 mimics for 24 h and treatment with 100 nM insulin for corresponding time periods, counter to those results in CBRH-7919 cells after similar procedures with miR-497 inhibitors and insulin. In addition, dual luciferase reporter assay further confirmed that miR-497 can bind to the 3'UTR of rat InsR.

CONCLUSION

Insulin receptor is the target gene of miR-497, and elevated miR-497 might induce hepatic insulin resistance in HFD-MetS E3 Rats through inhibiting the expression of insulin receptor and confining the activation of IRS-1/PI3K/Akt/GSK-3β/GS pathway to insulin.

Down-regulation of FBP1 by ZEB1-mediated repression confers to growth and invasion in lung cancer cells

Lung cancer is the most common type of malignant tumor, but the molecular mechanisms for lung cancer progression remains to be elusive. Here, we demonstrated that FBP1 (Fructose-1, 6-bisphosphatase) was frequently down-regulated in lung cancer tissues and cells, and FBP1 down-regulation was associated with poor prognosis in lung cancer patients. Restored FBP1 expression inhibited glucose uptake and lactate production, but induced oxygen consumption. Restored FBP1 expression also inhibited lung cancer cells proliferation and invasion under hypoxia in vitro, and inhibited lung cancer growth in vivo. Moreover, we confirmed DNA methylation in the promoter contributed to the decrease of FBP1 expression in lung cancer cells. We identified Zinc finger E-box-binding homeobox 1 (ZEB1) bond to FBP1 promoter to enhance DNA methylation in lung cancer cells. Our findings indicate that the down-regulation of FBP1 is a critical oncogenic event in lung cancer progression.

The Biological Functions of Non-coding RNAs: From a Line to a Circle

Non-coding RNAs have gained increasing attention, as their physiological and pathological functions are being gradually uncovered. MicroRNAs are the most well-studied ncRNAs, which play essential roles in translational repression and mRNA degradation. In contrast, long non-coding RNAs are distinguished from other small/short non-coding RNAs by length and regulate chromatin remodeling, gene transcription and posttranscriptional modifications. Recently, circular RNAs have emerged as endogenous, abundant, conserved and stable in mammalian cells. It has been demonstrated that circular RNAs can function as miRNA sponges. Other possible biological functions of circular RNAs are still under investigation. In this review, the biogenesis and biological functions of the three major types of ncRNAs, including miRNAs, lncRNAs and circRNAs, are overviewed. In addition, the role of ncRNAs in human diseases and potential clinical applications of ncRNAs are discussed.

HTLV-1 bZIP Factor RNA and Protein Impart Distinct Functions on T-cell Proliferation and Survival

Infection of T cells with human T-cell leukemia virus type-1 (HTLV-1) induces clonal proliferation and is closely associated with the onset of adult T-cell leukemia-lymphoma (ATL) and inflammatory diseases. Although Tax expression is frequently suppressed in HTLV-1-infected cells, the accessory gene, HTLV-1 bZIP factor (HBZ), is continuously expressed and has been implicated in HTLV-1 pathogenesis. Here, we report that transduction of mouse T cells with specific mutants of HBZ that distinguish between its RNA and protein activity results in differential effects on T-cell proliferation and survival. HBZ RNA increased cell number by attenuating apoptosis, whereas HBZ protein induced apoptosis. However, both HBZ RNA and protein promoted S-phase entry of T cells. We further identified that the first 50 bp of the HBZ coding sequence are required for RNA-mediated cell survival. Transcriptional profiling of T cells expressing wild-type HBZ, RNA, or protein revealed that HBZ RNA is associated with genes involved in cell cycle, proliferation, and survival, while HBZ protein is more closely related to immunological properties of T cells. Specifically, HBZ RNA enhances the promoter activity of survivin, an inhibitor of apoptosis, to upregulate its expression. Inhibition of survivin using YM155 resulted in impaired proliferation of several ATL cell lines as well as a T-cell line expressing HBZ RNA. The distinct functions of HBZ RNA and protein may have several implications for the development of strategies to control the proliferation and survival mechanisms associated with HTLV-1 infection and ATL.

The miR-101/RUNX1 feedback regulatory loop modulates chemo-sensitivity and invasion in human lung cancer

The deregulation of miR-101 has been implicated in multiple cancer types including lung cancer, but the exact role, mechanisms and how silencing of miR-101 remain elusive. Here we confirmed miR-101 downregulation in lung cancer cell lines and patient tissues. Restored miR-101 expression remarkably sensitized lung cancer cells to chemotherapy and inhibited invasion. Mechanistically, we indicated that miR-101 inversely correlated with RUNX1 expression, and identified RUNX1 as a novel target of miR-101. RUNX1 impaired the effects of miR-101 on chemotherapeutic sensitization and invasion inhibition. Moreover, RUNX1 knockdown resulted into increase of miR-101 expression and elevation of luciferase activity driven by miR-101 promoter in lung cancer cells, suggesting RUNX1 negatively transcriptionally regulated miR-101 expression via physically binding to miR-101 promoter. These findings support that miR-101 downregulation accelerates the progression of lung cancer via RUNX1 dependent manner and suggest that miR-101/RUNX1 feedback axis may have therapeutic value in treating refractory lung cancer.

Competing endogenous RNA: A novel posttranscriptional regulatory dimension associated with the progression of cancer

The existence of artificial sponges and antisense oligonucleotides designed to decrease the availability of microRNAs (miRNAs), a family of small non-coding RNAs that target RNA transcripts through miRNA response elements (MREs) involved in gene expression, suggests that miRNAs may also be regulated. The wide range of RNA transcripts harboring MREs, termed competing endogenous RNAs (ceRNAs), includes protein-coding messenger RNAs (mRNAs) and non-coding RNAs, for example long non-coding RNAs, pseudogenes and circular RNAs, which compete for a common pool of miRNAs as natural decoys. These ceRNAs are co-regulated and produce large, complex posttranscriptional regulatory networks, which have been implicated in numerous biological processes. The present review discusses recent discoveries that implicate natural microRNA decoys in the development of cancer.

High-level S100A6 promotes metastasis and predicts the outcome of T1-T2 stage in clear cell renal cell carcinoma

S100A6 (calcyclin), functions in cell cycle progression and differentiation, has been reported to promote the tumorigenesis and malignancy of many types of cancers. Clear cell renal cell carcinoma (ccRCC) is the most common subtype of RCC, lacking both promising prognostic markers and effective therapeutic targets. In our previous study, we have found the elevated S100A6 in the ccRCC tumor tissues, and the differentially expressed genes determined by microarray analysis were found to be strongly related to tumor metastasis after S100A6 knockdown and overexpression in the ccRCC cell line 786-O. The mRNA expression of S100A6 detected by RT-PCR in 6 cell lines and 174 tumor tissues, including 58 metastatic ccRCC and 116 clinicopathological features paired non-metastatic ccRCC (1:2), indicated S100A6 was elevated in the metastatic cells and tumor tissues. The protein expression was consistent with mRNA expression. The biological function of S100A6 in promoting metastasis was determined through overexpression and knockdown of S100A6 in the ccRCC cell lines 786-O, caki-1, and ACHN. In the scratch wound migration assay as well as migration and invasion assays, S100A6 knockdown significantly suppressed the migratory and invasive abilities of tumor cells, whereas overexpression enhanced the malignancy. Further research with the follow-up data of 129 ccRCC patients were analyzed by the Cox regression and survival analysis. The expression of S100A6 was up-regulated in metastatic ccRCC cells. In the metastatic tumor tissues, the expression of S100A6 was also higher than in the non-metastatic tissues. High S100A6 expression might be crucial to promote metastasis in ccRCC by enhancing the ability of tumor cells migration and invasion. In addition, the quantitative mRNA expression of S100A6 in the tumor tissues was an independent risk factor and might be used as a prognostic marker for the metastatic risk of the localized T1-T2 stage ccRCC.

HMGA1-pseudogene overexpression contributes to cancer progression

Two pseudogenes for HMGA1, whose overexpression has a critical role in cancer progression, have been identified. They act as decoy for miRNAs that are able to target the HMGA1 gene then enhancing cell proliferation and migration. Moreover, these pseudogenes contain sequences that are potential target sites for cancer-related miRNAs. Interestingly, HMGA1 pseudogenes are highly expressed in human anaplastic thyroid carcinomas, that is one of the most aggressive tumor in mankind, but almost undetectable in well differentiated thyroid carcinomas.