Regulation of tumor cell migration and invasion by the H19/let-7 axis is antagonized by metformin-induced DNA methylation

Inhibition of LCMR1 and ATG12 by demethylation-activated miR-570-3p is involved in the anti-metastasis effects of metformin on human osteosarcoma

Epidemiological studies have demonstrated that metformin could mitigate the progression of several tumors. Although it has been proved that metformin could cause demethylation of DNA and lead to up-regulation of some encoding genes and non-coding RNAs, there is little data about the effects of metformin on metastasis, and the interaction between metastasis and autophagy in human osteosarcoma cells. Here, we found miR-570-3p was significantly down-regulated in human metastatic osteosarcoma tissues but not in non-metastatic osteosarcoma tissues. Metformin attenuates the metastasis and autophagy in osteosarcoma. Interestingly, this autophagy favors osteosarcoma cells invasion. Moreover, reduction of metformin-induced inhibition of autophagy could reverse the invasion suppression in osteosarcoma. Mechanistically, metformin increases miR-570-3p by the demethylation of DNA, and the upregulation of miR-570-3p repressed the translation of its target, LCMR1 and ATG12. Our results, for the first time, presents evidence that the miR-570-3p-mediated suppression of LCMR1 and ATG12 is involved in the metformin-induced inhibition of metastasis in osteosarcoma cells.

Metformin, a first-line drug for type 2 diabetes mellitus, disrupts the MALAT1/miR-142-3p sponge to decrease invasion and migration in cervical cancer cells

The molecular mechanisms underlying the anti-neoplastic properties of metformin, a first-line drug for type 2 diabetes, remain elusive. To explore the novel anti-neoplastic mechanisms of metformin, the transwell chamber and wound-healing assays were used to evaluate its effects on the migration and invasion of human cervical cancer cells. Real-time PCR and Western blotting were used to measure the gene and protein expression, respectively, of microRNA (miRNA) miR-142-3p, long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript-1 (MALAT1), and high-mobility group AT-hook 2 (HMGA2). The dual-luciferase reporter assay system was used to examine the direct interaction between miR-142-3p and lncRNA MALAT1 and HMGA2. Immunofluorescence was used to detect the protein expression of HMGA2. In addition, tumor xenografts in a nude mouse model were developed to evaluate the anti-tumor efficacy of metformin. We found that metformin could suppress cervical cancer migration and invasion. During the process of tumor metastasis, miR-142-3p was significantly upregulated, whereas lncRNA MATAL1 and HMGA2 were suppressed by metformin. The binding site that allow the direct interaction between miR-142-3p and MALAT1 were located in the 3' untranslated region (3' UTR) of lncRNA MATAL1 and HMGA2 at base pairs (bp) 4452-5255, while that between miR-142-3p and HMGA2 was located at bp 1562-2521 of HMGA2. Metformin markedly inhibited the growth and angiogenesis of SiHa xenografts in nude mice. In conclusion, this study provides evidence that metformin can prevent the MALAT1/miR-142-3p sponge from developing anti-neoplastic properties in human cervical cancer cells and cervical cancer cell xenografts in nude mice. Thus, our findings demonstrate the novel anti-tumor effects of metformin in cervical cancer.

LncRNA H19 contributes to hippocampal glial cell activation via JAK/STAT signaling in a rat model of temporal lobe epilepsy

Background

Astrocyte and microglia activation are well-known features of temporal lobe epilepsy that may contribute to epileptogenesis. However, the mechanisms underlying glia activation are not well understood. Long non-coding RNA (lncRNA) H19 has diverse functions depending on physiological or pathological state, and its role in epilepsy is unknown. We previously demonstrated that H19 was significantly upregulated in the latent period of epilepsy and may be associated with cell proliferation and immune and inflammatory responses. We therefore speculated that H19 is involved in the hippocampal glial cell activation during epileptogenesis.

Methods

H19 was overexpressed or knocked down using an adeno-associated viral vector delivery system. A rat status epilepticus model was induced by intra-amygdala kainic acid injection. Astrocyte and microglia activation were assessed by immunofluorescence and western blot analyses. Expression of proinflammatory cytokines and components of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways were evaluated with western blotting.

Results

H19 overexpression induced the activation of astrocytes and microglia and the release of proinflammatory cytokines (interleukin-1β and interleukin-6 and tumor necrosis factor-α) in the hippocampus, whereas H19 knockdown inhibited status epilepticus-induced glial cell activation. Moreover, H19 activated JAK/STAT signaling by promoting the expression of Stat3 and c-Myc, which is thought to be involved in astrocyte activation.

Conclusions

LncRNA H19 contributes to hippocampal glial cell activation via modulation of the JAK/STAT pathway and could be a therapeutic tool to prevent the development of epilepsy.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1139-z) contains supplementary material, which is available to authorized users.

H19 Facilitates Tongue Squamous Cell Carcinoma Migration and Invasion via Sponging miR-let-7

The long noncoding RNA (lncRNA) H19 has been described to participate in the metastasis of various tumors. Nevertheless, whether H19 promotes or impedes tongue squamous cell carcinoma (TSCC) cell migration and invasion remains controversial. Here we found that the expression of H19 was elevated in TSCC tissues compared with adjacent normal tissues. Moreover, we demonstrated that the expression of H19 was higher in metastasized tumors compared with unmetastasized tumors. Consistently, TSCC cells express higher levels of H19 than human squamous cells. Subsequently, depletion of H19 impaired the migration and invasion abilities of TSCC cells. Mechanistically, we demonstrated that H19 functions as a competing endogenous RNA (ceRNA) to sponge miRNA let-7a, leading to an increase in a let-7a target, the key regulator of tumor metastasis HMGA2, which is enriched in TSCC tissues and cell lines. Intriguingly, inhibition of let-7a significantly rescued the short hairpin H19 (shH19)-induced decrease in TSCC migration and invasion. These findings revealed that the H19/let-7a/HMGA2/EMT axis plays a critical role in the regulation of TSCC migration and invasion, which may provide a new therapeutic target for TSCC.

Oncogenic mechanisms of Lin28 in breast cancer: new functions and therapeutic opportunities

The RNA binding protein Lin28 is best known for the critical role in cell development, recent researches also have implied its oncogenic function in various human cancers, including breast cancer. Specifically, aberrant Lin28 participates in multiple pathological processes, such as proliferation, metastasis, radiotherapy and chemotherapy resistance, metabolism, immunity and inflammation as well as stemness. In this review, we summarize the let-7-dependent and let-7-independent mechanism regulated by Lin28, focusing on its relation with tumor hallmarks in breast cancer, and subsequently discuss our present knowledge of Lin28 to develop a molecular-based therapeutic strategy against breast cancer.

CTD-2020K17.1, a Novel Long Non-Coding RNA, Promotes Migration, Invasion, and Proliferation of Serous Ovarian Cancer Cells In Vitro

Background

Ovarian cancer is the most lethal malignant tumor of the female reproductive system, and the metastasis is one of the major factors that contribute to the poor outcome of patients with OC. Accumulating evidence indicates that lncRNAs are expressed and play important regulatory roles in ovarian cancer.

Material/Methods

Aberrant lncRNAs in primary ovarian cancer tissues (POCTs) and paired omental metastasis tissues (OMTs) of patients with HGSOC were studied via lncRNA microarray. Real-time PCR was performed to examine CTD-2020K17.1 expression in HGSOC tissues from 38 patients, a normal ovarian surface epithelium cell line, and 4 ovarian cancer cell lines. Additionally, Transwell assays, wound healing assays, CCK-8 proliferation assays, and flow cytometry were used to explore the biological function of CTD-2020K17.1 in ovarian cancer cells. Finally, Western blot analysis was used to verify the potential target gene of CTD-2020K17.1.

Results

A novel lncRNA named CTD-2020K17.1 was identified via microarray analysis. Expression of CTD-2020K17.1 was significantly increased in OMTs and in 4 ovarian cancer cell lines compared with POCTs (P<0.05) or normal ovarian surface epithelial cell line (P<0.05). Moreover, CTD-2020K17.1 overexpression promoted migration, invasion, and proliferation of ovarian cancer cells, and CTD-2020K17.1 regulated the expression of CARD11.

Conclusions

CTD-2020K17.1 is significantly upregulated in OMTs and ovarian cancer cell lines. It can promote the migration, invasion, and proliferation of ovarian cancer cells, and CARD11 is regulated by CTD-2020K17.1.

H19 long noncoding RNA alters trophoblast cell migration and invasion by regulating TβR3 in placentae with fetal growth restriction

Fetal growth restriction (FGR) is a well-recognized risk factor for perinatal mortality and morbidity, as well as neurodevelopmental impairment and adulthood onset disorders. Here we report that the H19 long noncoding RNA (lncRNA) is significantly decreased in placentae from pregnancies with FGR. Downregulation of H19 leads to reduced migration and invasion of extravillous trophoblast (EVT) cells in vitro. This is consistent with reduced trophoblast invasion that has been observed in FGR. Genome-scale transcriptome profiling of EVT cells reveals significantly decreased expression of the type III TGF-β receptor (TβR3) following H19 knockdown. Decreased TβR3 expression is also seen in FGR placentae. TβR3 repression decreases EVT cell migration and invasion, owing to impaired TGF-β signaling through a non-canonical TGF-β signaling pathway. Further, we identify TβR3 as a novel regulatory target of microRNA let-7. We propose that dysregulation of this newly identified H19/TβR3-mediated regulatory pathway may contribute to the molecular mechanism of FGR. Our findings are the first to show a lncRNA-based mechanism of FGR, holding promise for the development of novel predictive, diagnostic, and therapeutic modalities for FGR.

Repurposing phenformin for the targeting of glioma stem cells and the treatment of glioblastoma

Glioblastoma (GBM) is the most aggressive primary brain tumor with poor prognosis. Here, we studied the effects of phenformin, a mitochondrial complex I inhibitor and more potent chemical analog of the diabetes drug metformin on the inhibition of cell growth and induction of apoptosis of glioma stem cells (GSCs) using both in vitro and in vivo models. Phenformin inhibited the self-renewal of GSCs, decreased the expression of stemness and mesenchymal markers and increased the expression of miR-124, 137 and let-7. Silencing of let-7 abrogated phenformin effects on the self-renewal of GSCs via a pathway associated with inhibition of H19 and HMGA2 expression. Moreover, we demonstrate that phenformin inhibited tumor growth and prolonged the overall survival of mice orthotopically transplanted with GSCs. Combined treatments of phenformin and temozolomide exerted an increased antitumor effect on GSCs in vitro and in vivo. In addition, dichloroacetate, an inhibitor of the glycolysis enzyme pyruvate dehydrogenase kinase, that decreases lactic acidosis induced by biguanides, enhanced phenformin effects on the induction of cell death in GSCs and prolonged the survival of xenograft-bearing mice. Our results demonstrate for the first time that phenformin targets GSCs and can be efficiently combined with current therapies for GBM treatment and GSC eradication.

Anti-tumor activity of metformin: from metabolic and epigenetic perspectives

Metformin has been used to treat type 2 diabetes for over 50 years. Epidemiological, preclinical and clinical studies suggest that metformin treatment reduces cancer incidence in diabetes patients. Due to its potential as an anti-cancer agent and its low cost, metformin has gained intense research interest. Its traditional anti-cancer mechanisms involve both indirect and direct insulin-dependent pathways. Here, we discussed the anti-tumor mechanism of metformin from the aspects of cell metabolism and epigenetic modifications. The effects of metformin on anti-cancer immunity and apoptosis were also described. Understanding these mechanisms will shed lights on application of metformin in clinical trials and development of anti-cancer therapy.

The lncRNA H19 positively affects the tumorigenic properties of glioblastoma cells and contributes to NKD1 repression through the recruitment of EZH2 on its promoter

The still largely obscure molecular events in the glioblastoma oncogenesis, a primary brain tumor characterized by an inevitably dismal prognosis, impel for investigation. The importance of Long noncoding RNAs as regulators of gene expression has recently become evident. Among them, H19 has a recognized oncogenic role in several types of human tumors and was shown to correlate to some oncogenic aspects of glioblastoma cells. Here we, hypothesyze that in glioblastoma H19 exerts its function through the interaction with the catalytic subunit of the PRC2 complex, EZH2. By employing a factor analysis on a SAGE dataset of 12 glioblastoma samples, we show that H19 expression in glioblastoma tissues correlates with that of several genes involved in glioblastoma growth and progression. H19 knock-down reduces viability, migration and invasiveness of two distinct human glioblastoma cell lines. Most importantly, we provide a mechanistic perspective about the role of H19 in glioblastoma cells, by showing that its expression is inversely linked to that of NKD1, a negative regulator of Wnt pathway, suggesting that H19 might regulate NKD1 transcription via EZH2-induced H3K27 trimethylation of its promoter. Indeed, we showed that H19 binds EZH2 in glioblastoma cells, and that EZH2 binding to NKD1 and other promoters is impaired by H19 silencing.

In this work we describe H19 as part of an epigenetic modulation program executed by EZH2, that results in the repression of Nkd1. We believe that our results can provide a new piece to the complex puzzle of H19 function in glioblastoma.

Metformin inhibits 17β-estradiol-induced epithelial-to-mesenchymal transition via βKlotho-related ERK1/2 signaling and AMPKα signaling in endometrial adenocarcinoma cells

The potential role of metformin in treating endometrial cancer remains to be explored. The current study investigated the role of metformin in 17β-estradiol-induced epithelial-mesenchymal transition (EMT) in endometrial adenocarcinoma cells. We found that 17β-estradiol promoted proliferation and migration, attenuated apoptosis in both estrogen receptor (ER) positive and ER negative endometrial adenocarcinoma cells (Ishikawa and KLE cells, respectively). Metformin abolished 17β-estradiol-induced cell proliferation and reversed 17β-estradiol-induced EMT in Ishikawa cells. In addition, metformin increased the expression of βKlotho, a fibroblast growth factors (FGFs) coreceptor, and decreased ERK1/2 phosphorylation in both Ishikawa and KLE cells. Decreased expression of βKlotho was noted in human endometrial adenocarcinomas, and plasmid-driven expression of βKlotho in Ishikawa cells abolished 17β-estradiol-induced EMT via inhibiting ERK1/2 signaling. βKlotho expression and metformin show synergetic effects on the proliferation and the EMT in Ishikawa cells. Furthermore, we demonstrated that the anti-EMT effects of metformin could be partly abolished by introducing Compound C, a specific AMPKα signaling inhibitor. In conclusion, metformin abolishes 17β-estradiol-induced cell proliferation and EMT in endometrial adenocarcinoma cells by upregulating βKlotho expression, inhibiting ERK1/2 signaling, and activating AMPKα signaling. Our study provides novel mechanistic insight into the anti-tumor effects of metformin.

Advances of Long Noncoding RNAs-mediated Regulation in Reproduction

OBJECTIVE

Advances in genomics and molecular biology have led to the discovery of a large group of uncharacterized long noncoding RNAs (lncRNAs). Emerging evidence indicated that many lncRNAs function in multiple biological processes and its dysregulation often causes diseases. Recent studies suggested that almost all regulatory lncRNAs interact with biological macromolecules such as DNA, RNA, and protein. LncRNAs regulate gene expression mainly on three levels, including epigenetic modification, transcription, and posttranscription, through DNA methylation, histone modification, and chromatin remodeling. LncRNAs can also affect the development of diseases and therefore be used to diagnose and treat diseases. With new sequencing and microarray techniques, hundreds of lncRNAs involved in reproductive disorders have been identified, but their functions in these disorders are undefined.

DATA SOURCES

This review was based on articles published in PubMed databases up to July 10, 2017, with the following keywords: "long noncoding RNAs", "LncRNA", "placentation", and "reproductive diseases".

STUDY SELECTION

Original articles and reviews on the topics were selected.

RESULTS

LncRNAs widely participate in various physiological and pathological processes as a new class of important regulatory factors. In spermatogenesis, spermatocytes divide and differentiate into mature spermatozoa. The whole process is elaborately regulated by the expression of phase-specific genes that involve many strains of lncRNAs. Literature showed that lncRNA in reproductive cumulus cells may contribute to the regulation of oocyte maturation, fertilization, and embryo development.

CONCLUSIONS

LncRNA has been found to play a role in the development of reproduction. Meanwhile, we reviewed the studies on how lncRNAs participate in reproductive disorders, which provides a basis for the study of lncRNA in reproduction regulation.

Long noncoding RNA H19 promotes transforming growth factor-β-induced epithelial-mesenchymal transition by acting as a competing endogenous RNA of miR-370-3p in ovarian cancer cells

Ovarian cancer is a gynecological malignant tumor with a high mortality rate among women, owing to metastatic progression and recurrence. Acquisition of invasiveness is accompanied by the loss of epithelial features and a gain of a mesenchymal phenotype, a process known as epithelial–mesenchymal transition (EMT). Transforming growth factor-β (TGF-β) has been implicated in the regulation of EMT. In the present study, we aimed to investigate the role of long noncoding RNA H19 and microRNA-370 (miR-370-3p) in TGF-β-induced EMT. Ovarian cancer cell lines SKOV-3 and OVCAR3 were incubated with different concentrations of TGF-β, and the results showed that TGF-β treatment upregulated H19 and downregulated miR-370-3p. In addition, an H19 knockdown or miR-370-3p overexpression suppressed TGF-β-induced EMT, while H19 overexpression or a miR-370-3p knockdown promoted TGF-β-induced EMT. Mechanistically, H19 could directly bind to miR-370-3p and effectively act as its competing endogenous RNA. Furthermore, we demonstrated that this activity of H19 was involved in its promotion of TGF-β-induced EMT. Thus, our results may provide novel insights into the process of TGF-β-induced EMT.

A Peroxidase Peroxiredoxin 1-Specific Redox Regulation of the Novel FOXO3 microRNA Target let-7

Precision in redox signaling is attained through posttranslational protein modifications such as oxidation of protein thiols. The peroxidase peroxiredoxin 1 (PRDX1) regulates signal transduction through changes in thiol oxidation of its cysteines. We demonstrate here that PRDX1 is a binding partner for the tumor suppressive transcription factor FOXO3 that directly regulates the FOXO3 stress response. Heightened oxidative stress evokes formation of disulfide-bound heterotrimers linking dimeric PRDX1 to monomeric FOXO3. Absence of PRDX1 enhances FOXO3 nuclear localization and transcription that are dependent on the presence of Cys31 or Cys150 within FOXO3. Notably, FOXO3-T32 phosphorylation is constitutively enhanced in these mutants, but nuclear translocation of mutant FOXO3 is restored with PI3K inhibition. Here we show that on H₂O₂ exposure, transcription of tumor suppressive miRNAs let-7b and let-7c is regulated by FOXO3 or PRDX1 expression levels and that let-7c is a novel target for FOXO3. Conjointly, inhibition of let-7 microRNAs increases let-7-phenotypes in PRDX1-deficient breast cancer cells. Altogether, these data ascertain the existence of an H₂O₂-sensitive PRDX1-FOXO3 signaling axis that fine tunes FOXO3 activity toward the transcription of gene targets in response to oxidative stress. Antioxid. Redox Signal. 28, 62-77.

Knockdown of long non-coding RNA H19 inhibits multiple myeloma cell growth via NF-κB pathway

Long non-coding RNAs (lncRNAs) are implicated in the complex network of cancer including Multiple myeloma (MM) and play important roles in tumor development. lncH19 was significantly up-regulated in multiple cancer types, suggesting it is a potential oncogene. However, the exact functions and downstream mechanisms are largely unknown. This study aimed to investigate whether H19 participates in the cell growth of MM and elucidate the underlying mechanism. We found that H19 was abnormally overexpressed in MM cell lines and sorted CD138⁺ MM bone marrow tissues. H19 knockdown induced by shRNA transfection significantly inhibited proliferation, viability and colony formation in MM cells, as well as inactivated NF-κB pathway. Moreover, combination treatment of H19 knockdown and NF-κB suppression (induced by specific inhibitor PDTC) produced synergistically inhibitory effects. Bone marrow expression of H19 was positively associated with circulating IL-6 or IL-8 level in the same MM patients. And patients with high expression of H19 had a lower survival rate. Taken together, we confirmed the abnormal upregulation of a novel lncRNA, H19, in human MM. H19 was involved in MM cell growth. The linkage between H19 and NF-κB pathway may provide a novel interpretation for the mechanism of H19's growth regulation in MM.

H19 lncRNA alters methylation and expression of Hnf4α in the liver of metformin-exposed fetuses

Metformin is the most widely used anti-diabetic medication worldwide. However, human and animal studies suggest that prenatal metformin exposure may increase the risk of metabolic disorders in adult offspring, yet the underpinning mechanism remains unclear. Here we report that metformin-exposed mouse fetuses exhibit elevated expression of the H19 long noncoding RNA, which induces hypomethylation and increased expression of hepatocyte nuclear factor 4α (HNF4α). As a transcription factor essential for morphological and functional differentiation of hepatocytes, HNF4α also has an indispensable role in the regulation of expression of gluconeogenic genes. Consistently, H19 overexpression in a human liver cell line leads to decreased methylation and increased expression of Hnf4α, with concomitant activation of the gluconeogenic program. Mechanistically, we show that the methylation change of Hnf4α is induced by H19-mediated regulation of S-adenosylhomocysteine hydrolase. We also provide evidence that altered H19 expression is a direct effect of metformin in the fetal liver. Our results suggest that metformin from the mother can directly act upon the fetal liver to modify Hnf4α expression, a key factor for both liver development and function, and that perturbation of this H19/Hnf4α-mediated pathway may contribute to the fetal origin of adult metabolic abnormalities.

LncRNAs regulate cancer metastasis via binding to functional proteins

Cancer is one of the leading causes of death worldwide, and metastasis is a crucial characteristic of malignancy. Recent studies have shown that lncRNAs play an important role in regulating cancer metastasis through various molecular mechanisms. We briefly summarize four known molecular functions of lncRNAs, including their role as a signal, decoy, guide and scaffold. No matter which pattern lncRNAs follow to carry out their functions, the proteins that lncRNAs bind to are important for them to exhibit their gene-regulating properties. We further illustrate that lncRNAs regulate the localization, stabilization or modification of their binding proteins to realize the binding role of lncRNAs. In this review, we focus on the interactions between lncRNAs and their binding proteins; moreover, we focus on the mechanisms of the collaborative work of lncRNAs and their binding proteins in cancer metastasis, thus evaluating the potential of lncRNAs as prospective novel therapeutic targets in cancer.

Functional prediction of long non-coding RNAs in ovarian cancer-associated fibroblasts indicate a potential role in metastasis

Cancer-associated fibroblasts (CAFs) contribute to the poor prognosis of ovarian cancer. Unlike in tumour cells, DNA mutations are rare in CAFs, raising the likelihood of other mechanisms that regulate gene expression such as long non-coding RNAs (lncRNAs). We aimed to identify lncRNAs that contribute to the tumour-promoting phenotype of CAFs. RNA expression from 67 ovarian CAF samples and 10 normal ovarian fibroblast (NOF) samples were analysed to identify differentially expressed lncRNAs and a functional network was constructed to predict those CAF-specific lncRNAs involved in metastasis. Of the 1,970 lncRNAs available for analysis on the gene expression array used, 39 unique lncRNAs were identified as differentially expressed in CAFs versus NOFs. The predictive power of differentially expressed lncRNAs in distinguishing CAFs from NOFs were assessed using multiple multivariate models. Interrogation of known transcription factor-lncRNA interactions, transcription factor-gene interactions and construction of a context-specific interaction network identified multiple lncRNAs predicted to play a role in metastasis. We have identified novel lncRNAs in ovarian cancer that are differentially expressed in CAFs compared to NOFs and are predicted to contribute to the metastasis-promoting phenotype of CAFs.

The H19-PEG10/IGF2BP3 axis promotes gastric cancer progression in patients with high lymph node ratios

We previously demonstrated that the lymph node ratio (LNR) is a prognostic factor associated with EGFR expression, among first priority genes amplified or overexpressed in cancer. Here, we investigated the associations between high LNR and second, third, and fourth priority genes. We performed mRNA expression microarray analysis of tumor tissue from patients with stage III gastric cancer and high or low LNRs. Candidate high LNR-associated genes were further evaluated in 39 patients with stage III gastric cancer. The functional relevance of these genes was evaluated in gastric cancer cell lines. We focused on five genes: H19,PEG10, IGF2BP3, CD177, and PGA3. H19 and PEG10 were confirmed as high LNR-associated genes. H19, PEG10, and IGF2BP3 were found to promote each other’s expression. Knocking down H19 or PEG10 using RNAi decreased cell proliferation, invasion, anchorage-independent growth, and chemoresistance. These genes had a mutual relationship in MKN7 cells. H19 knockdown decreased expression of epithelial-mesenchymal transition-associated genes in MKN74 cells to suppress transformation. Thus, H19 promotes epithelial-mesenchymal transition in gastric cancer and is a potential therapeutic target.

Effects of long non-coding RNA H19 and microRNA let7a expression on thyroid cancer prognosis

This study aims to explore the effects of long non-coding RNA H19 (lncRNA H19) and microRNA let7a (miRNA let7a) expression on the prognosis of thyroid cancer (TC). This may aid in the discovery of more effective treatment and prognosis approaches for TC. Between January 2008 and January 2011, 131 TC tissues and adjacent tissues were obtained from TC patients. An additional 122 normal thyroid tissues were also collected as normal controls from patients with benign thyroid lesions. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect lncRNA H19 and miRNA let7a mRNA expression. Five-year follow-ups were conducted. A Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic values of lncRNA H19 and miRNA let7a in TC. The Kaplan-Meier method was applied to analyze the 5-year survival rate of TC patients. Univariate and multivariate factor analyses were employed to analyze the prognostic factors of TC. The lncRNA H19 mRNA expression was higher while the miRNA let7a mRNA expression was lower in TC tissues than, in the normal thyroid tissues and adjacent tissues. The area under the ROC curve (AUC) of lncRNA H19 and miRNA let7a were 0.801 and 0.116, with sensitivity at 72.5% and 84%, as well as specificity 75.4% and 77%, respectively. In TC patients with tumor diameters≥1.0cm, lncRNA H19 mRNA expression was elevated, but miRNA let7a mRNA expression was reduced. This was also evident in TC patients with TNM stages III+IV and those with lymph node metastasis. TC patients with a lower 5-year survival rate showed upregulated levels of lncRNA H19 expression and, downregulated levels of miRNA let7a expression. LncRNA H19 and miRNA let7a expression, tumor diameter, TNM stage and lymph node metastasis were independent prognostic factors of TC. This study demonstrated that increased lncRNA H19 and decreased miRNA let7a expression levels are associated with poor prognosis in TC patients. An inverse relationship between lncRNA H19 and miRNA let7a expression levels was exhibited.

Dysregulated expression of long noncoding RNAs in gynecologic cancers

Cancers of the female reproductive system include ovarian, uterine, vaginal, cervical and vulvar cancers, which are termed gynecologic cancer. The emergence of long noncoding RNAs (lncRNAs), which are believed to play a crucial role in several different biological processes, has made the regulation of gene expression more complex. Although the function of lncRNAs is still rather elusive, their broad involvement in the initiation and progression of various cancers is clear. They are also involved in the pathogenesis of cancers of the female reproductive system. LncRNAs play a critical physiological role in apoptosis, metastasis, invasion, migration and cell proliferation in these cancers. Different expression profiles of lncRNAs have been observed in various types of tumors compared with normal tissues and between malignant and benign tumors. These differential expression patterns may lead to the promotion or suppression of cancer development and tumorigenesis. In the current review, we present the lncRNAs that show a differential expression between cancerous and normal tissues in ovarian, cervical and endometrial cancers, and highlight the associations between lncRNAs and some of the molecular pathways involved in these cancers.

Epigenetics in endometrial carcinogenesis - part 2: histone modifications, chromatin remodeling and noncoding RNAs

Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. In a previous review, we assessed DNA methylation alterations. The present review examines the contribution of histone modifications, chromatin remodeling and noncoding RNA alterations for endometrial carcinogenesis.

Metformin alters DNA methylation genome-wide via the H19/SAHH axis

The molecular mechanisms underlying the antineoplastic properties of metformin, a first-line drug for type 2 diabetes, remain elusive. Here we report that metformin induces genome-wide alterations in DNA methylation by modulating the activity of S-adenosylhomocysteine hydrolase (SAHH). Exposing cancer cells to metformin leads to hypermethylation of tumor-promoting pathway genes and concomitant inhibition of cell proliferation. Metformin acts by upregulating microRNA let-7 through AMPK activation, leading to degradation of H19 long noncoding RNA, which normally binds to and inactivates SAHH. H19 knockdown activates SAHH, enabling DNA methyltransferase 3B to methylate a subset of genes. This metformin-induced H19 repression and alteration of gene methylation are recapitulated in endometrial cancer tissue samples obtained from patients treated with antidiabetic doses of metformin. Our findings unveil a novel mechanism of action for the drug metformin with implications for the molecular basis of epigenetic dysregulation in cancer. This novel mechanism of action also may be occurring in normal cells.

Model-based unsupervised learning informs metformin-induced cell-migration inhibition through an AMPK-independent mechanism in breast cancer

We demonstrate that model-based unsupervised learning can uniquely discriminate single-cell subpopulations by their gene expression distributions, which in turn allow us to identify specific genes for focused functional studies. This method was applied to MDA-MB-231 breast cancer cells treated with the antidiabetic drug metformin, which is being repurposed for treatment of triple-negative breast cancer. Unsupervised learning identified a cluster of metformin-treated cells characterized by a significant suppression of 230 genes (p-value < 2E-16). This analysis corroborates known studies of metformin action: a) pathway analysis indicated known mechanisms related to metformin action, including the citric acid (TCA) cycle, oxidative phosphorylation, and mitochondrial dysfunction (p-value < 1E-9); b) 70% of these 230 genes were functionally implicated in metformin response; c) among remaining lesser functionally-studied genes for metformin-response was CDC42, down-regulated in breast cancer treated with metformin. However, CDC42's mechanisms in metformin response remained unclear. Our functional studies showed that CDC42 was involved in metformin-induced inhibition of cell proliferation and cell migration mediated through an AMPK-independent mechanism. Our results points to 230 genes that might serve as metformin response signatures, which needs to be tested in patients treated with metformin and, further investigation of CDC42 and AMPK-independence's role in metformin's anticancer mechanisms.

CASC2c as an unfavorable prognosis factor interacts with miR-101 to mediate astrocytoma tumorigenesis

miR-101 has been suggested as a tumor suppressor, but the promoter methylation and loss of heterozygosity didn't contribute to its low expression in astrocytoma. We investigated the role of a new long non-coding RNA CASC2c binding with miR-101. High CASC2c was positively correlated with astrocytoma progression, and an unfavorable prognosis factor for patients. Knockdown CASC2c inhibited proliferation and tumorgenesis. Overexpression of CASC2c promotes the malignant characteristic of astrocytoma cells.CASC2c directly bound miR-101 and mediated pre-miR-101 processing into mature miR-101, and functions as a competitor of miR-101 target genes such as CPEB1. Patients who possessed both low CASC2c and high miR-101 had a longer survival than those of low CASC2c alone or high miR-101 alone. In summary, CASC2c plays the onco-RNA role in the tumorgenesis of astrocytoma by acting as a decoy miR-101 sponge. Combination of low expression of CASC2c and high expression of miR-101 has an important referential significance to evaluate the prognosis of patients.

LncRNAs: From Basic Research to Medical Application

This review aimed to summarize the current research contents about long noncoding RNAs (lncRNAs) and some related lncRNAs as molecular biomarkers or therapy strategies in human cancer and cardiovascular diseases. Following the development of various kinds of sequencing technologies, lncRNAs have become one of the most unknown areas that need to be explored. First, the definition and classification of lncRNAs were constantly amended and supplemented because of their complexity and diversity. Second, several methods and strategies have been developed to study the characteristic of lncRNAs, including new species identifications, subcellular localization, gain or loss of function, molecular interaction, and bioinformatics analysis. Third, based on the present results from basic researches, the working mechanisms of lncRNAs were proved to be different forms of interactions involving DNAs, RNAs, and proteins. Fourth, lncRNA can play different important roles during the embryogenesis and organ differentiations. Finally, because of the tissue-specific expression of lncRNAs, they could be used as biomarkers or therapy targets and effectively applied in different kinds of diseases, such as human cancer and cardiovascular diseases.

Overexpression of FAM83H-AS1 indicates poor patient survival and knockdown impairs cell proliferation and invasion via MET/EGFR signaling in lung cancer

Whole transcriptome analyses of next generation RNA sequencing (RNA-Seq) data from human cancer samples reveled thousands of uncharacterized non-coding RNAs including long non-coding RNA (lncRNA). Recent studies indicated that lncRNAs are emerging as crucial regulators in cancer processes and potentially useful as biomarkers for cancer diagnosis and prognosis. To delineate dysregulated lncRNAs in lung cancer, we analyzed RNA-Seq data from 461 lung adenocarcinomas (LUAD) and 156 normal lung tissues. FAM83H-AS1, one of the top dysregulated lncRNAs, was found to be overexpressed in tumors relative to normal lung and significantly associated with worse patient survival in LUAD. We verified this diagnostic/prognostic potential in an independent cohort of LUAD by qRT-PCR. Cell proliferation, migration and invasion were decreased after FAM83H-AS1 knockdown using siRNAs in lung cancer cells. Flow cytometry analysis indicated the cell cycle was arrested at the G2 phase after FAM83H-AS1 knockdown. Mechanistically, we found that MET/EGFR signaling was regulated by FAM83H-AS1. Our study indicated that FAM83H-AS1 plays an important role in lung tumor progression and may be potentially used as diagnostic/prognostic marker. Further characterization of this lncRNA may provide a novel therapeutic target impacting MET/EGFR signaling.

Upregulated long non-coding RNA LINC00152 expression is associated with progression and poor prognosis of tongue squamous cell carcinoma

Altered expression of long non-coding RNAs (lncRNAs) associated with human carcinogenesis and might be used as diagnosis and prognosis biomarkers. However, the expression of lncRNAs in tongue squamous cell carcinoma (TSCC) and their relevance on the diagnosis, progression and prognosis of TSCC have not been thoroughly elucidated. To discover novel TSCC-related lncRNAs, we analyzed the lncRNA expression patterns in two sets of previously published TSCC gene expression profile data (GSE30784 and GSE9844), and found that long intergenic non-coding RNA 152 (LINC00152) was significantly upregulated in TSCC samples. We then detected LINC00152 expression in two other cohorts of TSCC samples. Quantitative Real time PCR (qRT-PCR) results indicated that LINC00152 was highly expressed in 15 primary TSCC biopsies when compared with 14 adjacent non-tumor tongue squamous cell epithelium samples. The expression of LINC00152 was also measured in 182 paraffin-embedded human TSCC tissues by in situ hybridization, increased expression of LINC00152 was significantly correlated with TSCC progression, such as T stage (p = 0.009), N stage (p = 0.036), TNM stage (p = 0.017), and associated with relapse (p < 0.001), and invasion (p < 0.001). Kaplan-Meier analysis demonstrated that increased LINC00152 expression contributed to both poor overall survival (p = 0.006) and disease-free survival (p = 0.007) of TSCC patients. These findings suggest that LINC00152 might serve as a potential biomarker for early detection and prognosis prediction of TSCC.

The Steroidogenic Acute Regulatory Protein (StAR) Is Regulated by the H19/let-7 Axis

The steroidogenic acute regulatory protein (StAR) governs the rate-limiting step in steroidogenesis, and its expression varies depending on the needs of the specific tissue. Tight control of steroid production is essential for multiple processes involved in reproduction, including follicular development, ovulation, and endometrial synchronization. Recently, there has been a growing interest in the role of noncoding RNAs in the regulation of reproduction. Here we demonstrate that StAR is a novel target of the microRNA let-7, which itself is regulated by the long noncoding RNA (lncRNA) H19. Using human and murine cell lines, we show that overexpression of H19 stimulates StAR expression by antagonizing let-7, which inhibits StAR at the post-transcriptional level. Our results uncover a novel mechanism underlying the regulation of StAR expression and represent the first example of lncRNA-mediated control of the rate-limiting step of steroidogenesis. This work thus adds to the body of literature describing the multiple roles in oncogenesis, cellular growth, glucose metabolism, and now regulation of steroidogenesis, of this complex lncRNA.

H19/let-7/LIN28 reciprocal negative regulatory circuit promotes breast cancer stem cell maintenance

Long noncoding RNA-H19 (H19), an imprinted oncofetal gene, has a central role in carcinogenesis. Hitherto, the mechanism by which H19 regulates cancer stem cells, remains elusive. Here we show that breast cancer stem cells (BCSCs) express high levels of H19, and ectopic overexpression of H19 significantly promotes breast cancer cell clonogenicity, migration and mammosphere-forming ability. Conversely, silencing of H19 represses these BCSC properties. In concordance, knockdown of H19 markedly inhibits tumor growth and suppresses tumorigenesis in nude mice. Mechanistically, we found that H19 functions as a competing endogenous RNA to sponge miRNA let-7, leading to an increase in expression of a let-7 target, the core pluripotency factor LIN28, which is enriched in BCSC populations and breast patient samples. Intriguingly, this gain of LIN28 expression can also feedback to reverse the H19 loss-mediated suppression of BCSC properties. Our data also reveal that LIN28 blocks mature let-7 production and, thereby, de-represses H19 expression in breast cancer cells. Appropriately, H19 and LIN28 expression exhibits strong correlations in primary breast carcinomas. Collectively, these findings reveal that lncRNA H19, miRNA let-7 and transcriptional factor LIN28 form a double-negative feedback loop, which has a critical role in the maintenance of BCSCs. Consequently, disrupting this pathway provides a novel therapeutic strategy for breast cancer.

Novel insight into triple-negative breast cancers, the emerging role of angiogenesis, and antiangiogenic therapy

Triple-negative breast cancer (TNBC) is a heterogeneous group of tumours characterised by lack of expression of oestrogen-, progesterone- and human epidermal growth factor receptors. TNBC, which represents approximately 15% of all mammary tumours, has a poor prognosis because of an aggressive behaviour and the lack of specific treatment. Accordingly, TNBC has become a major focus of research into breast cancer and is now classified into several molecular subtypes, each with a different prognosis. Pathological angiogenesis occurs at a late stage in the proliferation of TNBC and is associated with invasion and metastasis; there is an association with metabolic syndrome. Semaphorins are a versatile family of proteins with multiple roles in angiogenesis, tumour growth and metastasis and may represent a clinically useful focus for therapeutic targeting in this type of breast cancer. Another important field of investigation into the control of pathological angiogenesis is related to the expression of noncoding RNA (ncRNA) – these molecules can be considered as a therapeutic target or as a biomarker. Several molecular agents for intervening in the activity of different signalling pathways are being explored in TNBC, but none has so far proved effective in clinical trials and the disease continues to pose a defining challenge for clinical management as well as innovative cancer research.

Altered DNA Methylation of Long Noncoding RNA H19 in Calcific Aortic Valve Disease Promotes Mineralization by Silencing NOTCH1

BACKGROUND

Calcific aortic valve disease is characterized by an abnormal mineralization of the aortic valve. Osteogenic activity in the aortic valve is under the control of NOTCH1, which regulates the expression of key pro-osteogenic genes such as RUNX2 and BMP2. Long noncoding RNAs (lncRNAs) may reprogram cells by altering the gene expression pattern.

METHODS

Multidimensional genomic profiling was performed in human aortic valves to document the expression of lncRNAs and the DNA methylation pattern in calcific aortic valve disease. In-depth functional assays were carried out to document the impact of lncRNA on the mineralization of the aortic valve.

RESULTS

We documented that lncRNA H19 (H19) was increased in calcific aortic valve disease. Hypomethylation of the promoter region was observed in mineralized aortic valves and was inversely associated with H19 expression. Knockdown and overexpression experiments showed that H19 induces a strong osteogenic phenotype by altering the NOTCH1 pathway. Gene promoter analyses showed that H19 silenced NOTCH1 by preventing the recruitment of p53 to its promoter. A knockdown of H19 in valve interstitial cells (VICs) increased the expression of NOTCH1 and decreased the level of RUNX2 and BMP2, 2 downstream targets repressed by NOTCH1. In rescue experiments, the transfection of a vector encoding for the active Notch intracellular domain prevented H19-induced mineralization of valve interstitial cells.

CONCLUSIONS

These findings indicate that a dysregulation of DNA methylation in the promoter of H19 during calcific aortic valve disease is associated with a higher expression of this lncRNA, which promotes an osteogenic program by interfering with the expression of NOTCH1.

H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer

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High H19 expression in primary tumors is an independent predictor of short overall survival in CRC patients.

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RB1-E2F and CDK8-β-catenin signaling are essential in mediating the oncogenic activity of H19 in CRC.

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Combined analysis of H19 and its targets further improved the prediction power on overall survival of CRC patients.

Long noncoding RNAs (lncRNAs) are transcripts at least 200 nucleotides long that do not code for proteins. The clinical relevance of lncRNAs in colorectal cancer (CRC) is largely unknown. Here we identified that H19 expression in primary tumors is an independent prognostic predictor of poor prognosis of CRC patients and further proved its oncogenic role. To characterize the mechanisms, we profiled gene expression changes following H19 modulation in CRC cell lines and analyzed gene expression association in clinical datasets. Our data revealed important cancer-signaling pathways, including the RB1-E2F and the CDK8-β-catenin signaling, underlying H19 function.

The clinical significance of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) remains largely unexplored. Here, we analyzed a large panel of lncRNA candidates with The Cancer Genome Atlas (TCGA) CRC dataset, and identified H19 as the most significant lncRNA associated with CRC patient survival. We further validated such association in two independent CRC cohorts. H19 silencing blocked G1-S transition, reduced cell proliferation, and inhibited cell migration. We profiled gene expression changes to gain mechanism insight of H19 function. Transcriptome data analysis revealed not only previously identified mechanisms such as Let-7 regulation by H19, but also RB1-E2F1 function and β-catenin activity as essential upstream regulators mediating H19 function. Our experimental data showed that H19 affects phosphorylation of RB1 protein by regulating gene expression of CDK4 and CCND1. We further demonstrated that reduced CDK8 expression underlies changes of β-catenin activity, and identified that H19 interacts with macroH2A, an essential regulator of CDK8 gene transcription. However, the relevance of H19-macroH2A interaction in CDK8 regulation remains to be experimentally determined. We further explored the clinical relevance of above mechanisms in clinical samples, and showed that combined analysis of H19 with its targets improved prognostic value of H19 in CRC.

Long Non-coding RNA HOXA11 Antisense Promotes Cell Proliferation and Invasion and Predicts Patient Prognosis in Serous Ovarian Cancer

PURPOSE

The biological function of long non-coding RNAs (lncRNAs) is only partially understood; therefore, in this study, we investigated the expression of the novel HOXA11 antisense (HOXA11as) lncRNA and its oncogenic role in serous ovarian cancer (SOC).

MATERIALS AND METHODS

HOXA11as expression was examined in 129 SOC tissue samples by real time reverse transcription polymerase chain reaction. Clinicopathological factors and patient survival were compared between the high (n=27) and low HOXA11as expression group (n=102). To investigate the role of HOXA11as in cell proliferation, invasion, and migration, HOXA11as expression in ovarian cancer cells was knocked down using RNA interference.

RESULTS

HOXA11as expression in cancer tissue was 77-fold higher than that of noncancerous tissue (p < 0.05). Higher HOXA11as expression was significantly correlated with histological grade (p=0.017) and preoperative cancer antigen 125 (p=0.048). HOXA11as overexpression in SOC cells led to increased cell proliferation, invasion, and migration. Moreover, HOXA11as was associated with the expression of genes involved in cell invasion, migration, and epithelial-mesenchymal transition (EMT), including vascular endothelial growth factor, matrix metalloproteinase 9 (MMP-9), B-catenin, E-cadherin, Snail, Twist, and vimentin. Multivariate analysis revealed that HOXA11as was a prognostic factor of progressive disease and mortality (hazard ratio [HR], 1.730; p=0.043 and HR, 2.170; p=0.033, respectively). Progression-free and overall survival were significantly shorter in patients with high HOXA11as expression.

CONCLUSION

These findings highlight the clinical significance of HOXA11as to predicting the prognosis of SOC patients and suggest its potential in promoting tumor aggressiveness via regulation of vascular endothelial growth factor (VEGF), MMP-9, and EMT-related mechanisms.

Long non-coding RNA H19 enhances cell proliferation and anchorage-independent growth of cervical cancer cell lines

Long non-coding RNA H19 is aberrantly expressed in multiple malignancies and its expression levels correlate with recurrence, metastasis, and patient survival. Despite numerous reports documenting the role of H19 in carcinogenesis, its contribution to cervical cancer development is still largely unknown. In this study, I observed that H19 expression was elevated in cervical cancer cell lines and could be detected in extracellular vesicles in the culture medium. In addition, I demonstrated, by overexpression and knockdown experiments, that H19 promoted cell proliferation and multicellular tumor spheroid formation without significantly affecting apoptosis and cell migration. Finally, treatment with transforming growth factor beta and hypoxia-mimetic CoCl₂ could modulate H19 levels in a cell line-specific manner. These findings indicate that H19 promotes both anchorage-specific and -independent growth of cervical cancer cell lines and may serve as a potential target for cancer diagnosis and therapy.

Posttranscriptional regulation of intestinal epithelial integrity by noncoding RNAs

Maintenance of the gut epithelial integrity under stressful environments requires epithelial cells to rapidly elicit changes in gene expression patterns to regulate their survival, adapt to stress, and keep epithelial homeostasis. Disruption of the intestinal epithelial integrity occurs commonly in patients with various critical illnesses, leading to the translocation of luminal toxic substances and bacteria to the blood stream. Recently, noncoding RNAs (ncRNAs) have emerged as a novel class of master regulators of gene expression and are fundamentally involved in many aspects of gut mucosal regeneration, protection, and epithelial barrier function. Here, we highlight the roles of several intestinal epithelial tissue-specific microRNAs, including miR-222, miR-29b, miR-503, and miR-195, and long ncRNAs such as H19 and SPRY4-IT1 in the regulation of cell proliferation, apoptosis, migration, and cell-to-cell interactions and also further analyze the mechanisms through which ncRNAs and their interactions with RNA-binding proteins modulate the stability and translation of target mRNAs. WIREs RNA 2017, 8:e1399. doi: 10.1002/wrna.1399 For further resources related to this article, please visit the WIREs website.

Long non-coding RNA H19 regulates FOXM1 expression by competitively binding endogenous miR-342-3p in gallbladder cancer

Background

Long non-coding RNA (lncRNA) H19 has been reported to involve in many kinds of human cancers and functions as an oncogene. Our previous study found that H19 was over-expressed in gallbladder cancer (GBC) and was shown to promote tumor development in GBC. However, the competing endogenous RNA (ceRNA) regulatory network involving H19 in GBC progression has not been fully elucidated. We aim to detect the role of H19 as a ceRNA in GBC.

Methods and Results

In this study, the expression of H19 and miR-342-3p were analyzed in 35 GBC tissues and matched normal tissues by using quantitative polymerase chain reaction (qRT-PCR). We demonstrated H19 was overexpressed and negatively correlated with miR-342-3p in GBC. By dual-luciferase reporter assays, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays, we verified that H19 was identified as a direct target of miR-342-3p. QRT-PCR and Western-blotting assays demonstrated that H19 silencing down-regulated, whereas over-expression enhanced the expression of miR-342-3p targeting FOXM1 through competitively ‘sponging’ miR-342-3p. Furthermore, transwell invasion assays and cell cycle assays indicated that H19 knockdown inhibited both cells invasion and proliferation, but this effects was attenuated by co-transfection of siRNA-H19 and miR-342-3p inhibitor in GBC cells. In vivo, tumor volumes were decreased significantly in H19 silenced group compared to the control group, but was attenuated by co-transfection of shRNA-H19 and miR-342-3p inhibitor, which were stablely constructed through lenti-virus vector.

Conclusion

Our results suggest a potential ceRNA regulatory network involving H19 regulates FOXM1 expression by competitively binding endogenous miR-342-3p in GBC. This mechanism may contribute to a better understanding of GBC pathogenesis and provides potential therapeutic strategy for GBC.

Long non-coding RNAs: potential new biomarkers for predicting tumor invasion and metastasis

Long non-coding RNAs (lncRNAs) play important roles in malignant neoplasia. Indeed, many hallmarks of cancer define that the malignant phenotype of tumor cells are controlled by lncRNAs. Despite a growing number of studies highlighting their importance in cancer, there has been no systematic review of metastasis-associated lncRNAs in various cancer types. Accordingly, we focus on the key metastasis-related lncRNAs and outline their expression status in cancer tissues by reviewing the previous stuides, in order to summarize the nowadays research achivements for lncRNAs related to cancer metastasis. Medline, EMBASE, as well as PubMed databases were applied to study lncRNAs which were tightly associated with tumor invasion and metastasis. Up to now, a substantial number of lncRNAs have been found to have important biological functions. In this review, according to their various features in cancer, lncRNAs were roughly divided into three categories: promoting tumor invasion and metastasis, negative regulation of tumor metastasis and with dual regulatory roles. The present studies may establish the foundation for both further research on the mechanisms of cancer progression and future lncRNA-based clinical applications.

Circulating miRNAs in Murine Experimental Endometriosis

Endometriosis is a chronic disease that commonly affects women of reproductive age; however, diagnosis is often delayed due to lack of appreciation of early signs and symptoms. Development of a noninvasive biomarker would significantly reduce delays in diagnosis and treatment. Circulating microRNAs (miRNAs) have been implicated as biomarkers for several diseases including endometriosis. Here, we use an miRNA array to investigate differential miRNA abundance in the serum of mice after induction of experimental endometriosis. let-7a-5p was decreased in the serum of mice with endometriosis. let-7b-5p, c-5p, and e-5p also showed a trend toward downregulation. Serum let-7 family miRNA shows similar dysregulation in endometriosis in both humans and mice. Diminished circulating let-7 implies a complex regulation that potentially involves multiple organs. Further investigation is necessary to determine the functional roles of let-7 miRNAs in this disease.

The Role of Long Non-Coding RNAs in Ovarian Cancer

Background:

Mesenchymal stem cells (MSCs) are important candidates for MSC-based cellular therapy. Current paradigm states that MSCs support local progenitor cells in damaged tissue through paracrine signaling. Therefore, the study of paracrine effects and secretome of MSCs could lead to the appreciation of mechanisms and molecules associated with the therapeutic effects of these cells. This study analyzed anti-inflammatory and immune-modulatory effects of MSC secretomes derived from embryonic stem cells (ESCs) and bone marrow cells after hypoxia and normoxia preconditioning.

Methods:

ESCs differentiated into MSCs and characterized by flow cytometry as well as by differentiation into adipocytes and osteoblasts. The experimental groups were consisted of individual groups of ESC-MSCs and BM-MSCs (bone marrow-derived mesenchymal stromal cells), which were preconditioned with either hypoxia or normoxia for 24, 48 and 72 h. After collecting the cell-free medium from each treatment, secretomes were concentrated by centrifugal filters. Using a peripheral blood mononuclear cell (PBMC) assay and ELISA, IL-10 concentration in PBMCs was evaluated after their incubation with different secretomes from preconditioned and non-preconditioned MSCs.

Results:

A significant difference was observed between ESC-MSC normoxia and ESC-MSC hypoxia in IL-10 concentration, and normoxia secretomes increased IL-10 secretion from PBMCs. Moreover, the strongest IL-10 secretion from PBMCs could be detected after the stimulation by ESC-MSC conditioned secretomes, but not BM-MSC conditioned medium.

Conclusions:

Human hypoxia preconditioned ESC-MSC secretome indicated stronger immune-modulatory effects compared to BM-MSC conditioned medium. It could be suggested that induced MSCs confer less immune-modulatory effects but produce more inflammatory molecules such as tumor necrosis factor α, which needs further investigation.

The emerging role of long non-coding RNAs in endometrial cancer

The human genome is pervasively transcribed and approximately 98% of the genome is non-coding. Long non-coding RNAs (lncRNAs) are a heterogeneous group of RNA transcripts that are >200 nucleotides in length with minimal to no protein-coding potential. Similar to proteins, lncRNAs have important biological functions in both normal cells and disease states including many types of cancer. This review summarizes recent advances in our understanding of lncRNAs in cancer biology and highlights the potential for lncRNA as diagnostic biomarkers and therapeutics. Herein we focus on the poorly understood role of lncRNAs in endometrial cancer, the most common gynecologic malignancy in the developed world.

Genomic Alteration in Head and Neck Squamous Cell Carcinoma (HNSCC) Cell Lines Inferred from Karyotyping, Molecular Cytogenetics, and Array Comparative Genomic Hybridization

Genomic alteration in head and neck squamous cell carcinoma (HNSCC) was studied in two cell line pairs (HN30-HN31 and HN4-HN12) using conventional C-banding, multiplex fluorescence in situ hybridization (M-FISH), and array comparative genomic hybridization (array CGH). HN30 and HN4 were derived from primary lesions in the pharynx and base of tongue, respectively, and HN31 and HN12 were derived from lymph-node metastatic lesions belonging to the same patients. Gain of chromosome 1, 7, and 11 were shared in almost all cell lines. Hierarchical clustering revealed that HN31 was closely related to HN4, which shared eight chromosome alteration cases. Large C-positive heterochromatins were found in the centromeric region of chromosome 9 in HN31 and HN4, which suggests complex structural amplification of the repetitive sequence. Array CGH revealed amplification of 7p22.3p11.2, 8q11.23q12.1, and 14q32.33 in all cell lines involved with tumorigenesis and inflammation genes. The amplification of 2p21 (SIX3), 11p15.5 (H19), and 11q21q22.3 (MAML2, PGR, TRPC6, and MMP family) regions, and deletion of 9p23 (PTPRD) and 16q23.1 (WWOX) regions were identified in HN31 and HN12. Interestingly, partial loss of PTPRD (9p23) and WWOX (16q23.1) genes was identified in HN31 and HN12, and the level of gene expression tended to be the down-regulation of PTPRD, with no detectable expression of the WWOX gene. This suggests that the scarcity of PTPRD and WWOX genes might have played an important role in progression of HNSCC, and could be considered as a target for cancer therapy or a biomarker in molecular pathology.

Long Noncoding RNAs: From Clinical Genetics to Therapeutic Targets?

Recent studies suggest that the majority of the human genome is transcribed, but only about 2% accounts for protein-coding exons. Long noncoding RNAs (lncRNAs) constitute a heterogenic class of RNAs that includes, for example, intergenic lncRNAs, antisense transcripts, and enhancer RNAs. Moreover, alternative splicing can lead to the formation of circular RNAs. In support of putative functions, GWAS for cardiovascular diseases have shown predictive single-nucleotide polymorphisms in lncRNAs, such as the 9p21 susceptibility locus that encodes the lncRNA antisense noncoding RNA in the INK4 locus (ANRIL). Many lncRNAs are regulated during disease. For example, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and myocardial infarction-associated transcript (MIAT) were shown to affect endothelial cell functions and diabetic retinopathy, whereas lincRNA-p21 controls neointima formation. In the heart, several lncRNAs were shown to act as microRNA sponges and to control ischemia-reperfusion injury or act as epigenetic regulators. In this review, the authors summarize the current understanding of lncRNA functions and their role as biomarkers in cardiovascular diseases.

Long noncoding RNA H19 mediates melatonin inhibition of premature senescence of c-kit(+) cardiac progenitor cells by promoting miR-675

Melatonin, a hormone secreted by the pineal gland, possesses multiple biological activities such as antitumor, antioxidant, and anti-ischemia. C-kit(+) cardiac progenitor cells (CPCs) have emerged as a promising tool for the treatment of heart diseases. However, the senescence of CPCs due to pathological stimuli leads to the decline of CPCs' functions and regenerative potential. This study was conducted to demonstrate whether melatonin antagonizes the senescence of CPCs in response to oxidative stress. Here, we found that the melatonin treatment markedly inhibited the senescent characteristics of CPCs after exposed to sublethal concentration of H2 O2 , including the increase in senescence-associated β-galactosidase (SA-β-gal)-positive CPCs, senescence-associated heterochromatin loci (SAHF), secretory IL-6 level, and the upregulation of p53 and p21 proteins. Senescence-associated proliferation reduction was also attenuated by melatonin in CPCs. Luzindole, the melatonin membrane receptor blocker, may block the melatonin-mediated suppression of premature senescence in CPCs. Interestingly, we found that long noncoding RNA H19 and its derived miR-675 were downregulated by H2 O2 in CPCs, but melatonin treatment could counter this alteration. Furthermore, knockdown of H19 or miR-675 blocked antisenescence actions of melatonin on H2 O2 -treated CPCs. It was further verified that H19-derived miR-675 targeted at the 3'UTR of USP10, which resulted in the downregulation of p53 and p21 proteins. In summary, melatonin antagonized premature senescence of CPCs via H19/miR-675/USP10 pathway, which provides new insights into pharmacological actions and potential applications of melatonin on the senescence of CPCs.

An overview of long non-coding RNAs in ovarian cancers

As with miRNAs a decade ago, the scientific community recently understood that lncRNAs represent a new layer of complexity in the regulation of gene expression. Although only a subset of lncRNAs has been functionally characterized, it is clear that they are deeply involved in the most critical physiological and pathological biological processes. This review shows that in ovarian carcinoma, data already available testify to the importance of lncRNAs and that the demonstration of an ever-growing role of lncRNAs in the biology of this malignancy can be expected from future studies. We also underline the importance of their relationship with associated protein partners and miRNAs. Together, the available information suggests that the emerging field of lncRNAs will pave the way for a better understanding of ovarian cancer biology and might lead to the development of innovative therapeutic approaches. Moreover, lncRNAs expression signatures either alone or in combination with other types of markers (miRNAs, mRNAs, proteins) could prove useful to predict outcome or treatment follow-up in order to improve the therapeutic care of ovarian carcinoma patients.

Long Noncoding RNA: Recent Updates in Atherosclerosis

Long noncoding RNAs belong to a class of noncoding RNAs longer than 200 nucleotides with the epigenetic regulation potential. As a novel molecular regulator, lncRNAs are often dysregulated in various pathological conditions and display multiple functions in a wide range of biological processes. Given that recent studies have indicated that lncRNAs are involved in atherosclerosis-related smooth muscle cell, endothelial cell, macrophage and lipid metabolism regulation, it is pertinent to understand the potential function of lncRNAs in atherosclerosis development. This review will highlight the recent updates of lncRNAs in atherogenesis and also discuss their potential roles as novel therapeutic targets.