Molecular mechanisms of long noncoding RNAs on gastric cancer. Oncotarget. 2016;7:8601-8612. [PMID: 26788991 PMCID: PMC4890990 DOI: 10.18632/oncotarget.6926]

Long noncoding RNA DLX6-AS1 promotes breast cancer progression via miR-505-3p/RUNX2 axis

The dysregulation of long non-coding RNA (lncRNA) DLX6-AS1 has been identified to be involved in the development of several cancers, but its functional role and the underlying mechanism of DLX6-AS1 in breast cancer (BC) remains unknown. In the current study, the expression of DLX6-AS1 in the BC tissue samples was evaluated and the correlation between DLX6-AS1 expression and clinicopathological parameters were also analyzed. We found that DLX6-AS1 expression was much higher in tumor tissues than that in adjacent normal tissues and was positively associated with poor prognosis in BC patients. DLX6-AS1 knockdown significantly suppressed BC cell proliferation, invasion, migration, and promoted apoptosis. Moreover, luciferase reporter assay validated that DLX6-AS1 acted as an endogenous sponge to miR-505-3p and negatively regulated its expression. Additionally, miR-505-3p inhibited runt-related transcription factor 2 (RUNX2) expression by directly bind to its 3'- untranslated region (3'-UTR) and overexpression of RUNX2 partially reversed the effect of miR-505-3p mimics on BC cell proliferation and invasion. Furthermore, in BC tissues, miR-505-3p expression level was inversely associated with DLX6-AS1 and RUNX2, respectively. In conclusion, these findings demonstrated that DLX6-AS1 functioned as an oncogenic role that promoted BC proliferation and invasion through miR-505-3p/RUNX2 axis, which might serve as a potential therapeutic target for BC treatment.

LncRNA NORAD Promotes Proliferation And Inhibits Apoptosis Of Gastric Cancer By Regulating miR-214/Akt/mTOR Axis

PURPOSE

In previous studies, we confirmed that the overexpression of lncRNA NORAD was associated with the occurrence and development of gastric cancer (GC). The aim of the present study was to explore the molecular mechanism of lncRNA NORAD on GC cell proliferation and apoptosis in vitro and in vivo.

PATIENTS AND METHODS

The quantitative Real-Time PCR (qRT-PCR) was used to determine the expression levels of lncRNA NORAD and miR-214 in GC tissues and cells. The interaction between lncRNA NORAD and miR-214 was investigated by biological information and Dual-Luciferase gene reporter assay. Effect of lncRNA NORAD on GC tumor growth in vivo was studied in tumor xenograft model mice. The apoptosis of GC cells was determined by flow cytometry. The proliferation of GC cells was determined by 5-ethynyl-2´-deoxyuridine (EDU) and colony formation assays. Western Blot was used to determine the expressions of caspase-3, Akt and mTOR in GC tissues and cells.

RESULTS

The qRT-PCR results showed that lncRNA NORAD was highly expressed in human GC tissues and cell lines, while miR-214 was significantly down-regulated. Meanwhile, there was a direct interaction between lncRNA NORAD and miR-214. In addition, lncRNA NORAD could promote the growth and proliferation of GC cells both in vivo and in vitro. NOARD could also inhibit the apoptosis of GC cells by down-regulating caspase-3; however, miR-214 overexpression attenuated this effect. Moreover, lncRNA NORAD promoted the phosphorylation of Akt and mTOR in mouse GC tissues and GC cell lines, while miR-214 mimics inhibited that promotion.

CONCLUSION

These results suggested that NORAD could promote the development of GC by inhibiting miR-214 expression and activating the Akt/mTOR signaling pathway.

Identification of differentially expressed circRNAs and a novel hsa_circ_0000144 that promote tumor growth in gastric cancer

Background

Circular RNAs (circRNAs) are involved in regulating tumor pathogenesis. The mechanism of circRNAs in gastric cancer (GC) is still unknown. Our study aimed to identify differentially expressed circRNAs and assess a novel circRNA (hsa_circ_0000144) in the proliferation, migration, and invasion in GC.

Methods

Gene ontology (GO) enrichment and analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, pathway network, and the ceRNA regulatory network of hsa_circ_0000144 targeting miRNAs and mRNAs were performed with the help of bioinformatics using R language and Perl software. hsa_circ_0000144 expression and circRNA knockdown in GC cell lines were detected using quantitative PCR (qPCR) in vitro. Cell proliferation, migration, and invasion after circRNA knockdown were measured using the cell counting kit-8 assay and Transwell assay.

Results

The circRNA expression profile GSE78092 downloaded from the Gene Expression Omnibus database included three GC patients and three normal tissues. Thirty-two differentially expressed circRNAs comprised six upregulated circRNAs and 26 downregulated circRNAs. In particular, the ErbB signaling pathway, neurotrophin signaling pathway, cellular senescence, and pathways in bladder cancer and GC played the most important roles in the pathway network. The expression of hsa_circ_0000144 was upregulated in GC cell lines. Hsa_circ_0000144 knockdown suppressed tumor growth in vitro.

Conclusions

Hsa_circ_0000144 promotes GC cell proliferation, migration, and invasion, and the ceRNA regulatory network of hsa_circ_0000144 targeting miRNAs and mRNAs might be biomarkers for GC diagnosis and targeted therapy.

LncRNAs as potential diagnostic and prognostic biomarkers in gastric cancer: A novel approach to personalized medicine

Gastric cancer is the third leading cause of cancer death with 5-year survival rate of about 30-35%. Since early detection is associated with decreased mortality, identification of novel biomarkers for early diagnosis and proper management of patients with the best response to therapy is urgently needed. Long noncoding RNAs (lncRNAs) due to their high specificity, easy accessibility in a noninvasive manner, as well as their aberrant expression under different pathological and physiological conditions, have received a great attention as potential diagnostic, prognostic, or predictive biomarkers. They may also serve as targets for treating gastric cancer. In this review, we highlighted the role of lncRNAs as tumor suppressors or oncogenes that make them potential biomarkers for the diagnosis and prognosis of gastric cancer. Relatively, lncRNAs such as H19, HOTAIR, UCA1, PVT1, tissue differentiation-inducing nonprotein coding, and LINC00152 could be potential diagnostic and prognostic markers in patients with gastric cancer. Also, the impact of lncRNAs such as ecCEBPA, MLK7-AS1, TUG1, HOXA11-AS, GAPLINC, LEIGC, multidrug resistance-related and upregulated lncRNA, PVT1 on gastric cancer epigenetic and drug resistance as well as their potential as therapeutic targets for personalized medicine was discussed.

Suppression of MALAT1 ameliorates chronic constriction injury-induced neuropathic pain in rats via modulating miR-206 and ZEB2

Long noncoding RNAs (lncRNAs) are involved in multiple nervous system diseases, including neuropathic pain. Previous studies have demonstrated that lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been identified as a diagnostic biomarker in many diseases. Nevertheless, the function of MALAT1 in neuropathic pain progression is still unclear. Here, we established a chronic constriction injury (CCI) rat model. We found that MALAT1 was remarkably upregulated in CCI rats. In addition, neuropathic pain behaviors such as mechanical and thermal hyperalgesia were reduced by the inhibition of MALAT1. Meanwhile, the loss of MALAT1 was able to depress the neuroinflammation process via the inhibition of COX-2, interleukin-1β, and interleukin-6. A previous study has indicated that miR-206 upregulation can restrain the CCI-induced neuropathic pain. Furthermore, we exhibited that miR-206 was significantly downregulated and silence of MALAT1 restrained its expression in CCI rats. For another, ZEB2 was a target of miR-206 and it was shown that ZEB2 was elevated in CCI rats in a time-dependent manner. Overexpression of miR-206 obviously suppressed ZEB2 levels in rat microglial cells. Subsequently, it was demonstrated that upregulation of miR-206 rescued the neuropathic pain triggered by ZEB2 overexpression in vivo through neuroinflammation inhibition. Overall, we indicated that suppression of MALAT1 ameliorated neuropathic pain progression via miR-206/ZEB2 axis.

Long noncoding RNA NEAT1 suppresses sorafenib sensitivity of hepatocellular carcinoma cells via regulating miR-335-c-Met

OBJECTIVES

To investigate the role of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating sorafenib (Sora) sensitivity of hepatocellular carcinoma (HCC) cells and possible signaling pathways.

METHODS

HCC cell lines and tumor tissue were quantified for NEAT1 expression by quantitative polymerase chain reaction (qPCR). Following shRNA (short hairpin RNA) knockdown of NEAT1, cell viability, apoptosis, and related protein expression were measured after drug treatment. The downstream target of NEAT1, including miR-335 and c-Met was studied using a combination of luciferase binding assay, gene knockdown/overexpression, western blot analysis, and cell viability/apoptosis assay. Cancer cells with NEAT1 knockdown were transplanted onto nude mice for in vivo tumorigenesis assay.

RESULTS

Silencing of NEAT1 in HCC cells facilitated Sora sensitivity by enhancing drug-induced apoptosis, and led to smaller tumor size on nude mice. Mechanistic study suggested that miR-335 was negatively regulated by NEAT1, and miR-335 further suppressed c-Met-Akt pathway, whose activation caused drug resistance of HCC cells. The knockdown of miR-335, or overexpression of c-Met, all remarkably abolished the proapoptotic effect of NEAT1 knockdown in HCC cells.

CONCLUSION

lncRNA NEAT1 mediates Sora resistance of HCC cells by suppressing miR-335 expression, and disinhibition on c-Met-Akt signaling pathway. Our results provide potency of NEAT1 as the biomarker for drug resistant HCC and possible treating targets.

Long non-coding RNAs in prostate cancer: Functional roles and clinical implications

Long noncoding RNAs (lncRNAs) are defined as RNA transcripts longer than 200 nucleotides that do not encode proteins. LncRNAs have been documented to exhibit aberrant expression in various types of cancer, including prostate cancer. Currently, screening for prostate cancer results in overdiagnosis. The consequent overtreatment of patients with indolent disease in the clinic is due to the lack of appropriately sensitive and specific biomarkers. Thus, the identification of lncRNAs as novel biomarkers and therapeutic targets for prostate cancer is promising. In the present review, we attempt to summarize the current knowledge of lncRNA expression patterns and mechanisms in prostate cancer. In particular, we focus on lncRNAs regulated by the androgen receptor and the specific molecular mechanism of lncRNAs in prostate cancer to provide a potential clinical therapeutic strategy for prostate cancer.

Clinical significances of hsa_circ_0067582 and hsa_circ_0005758 in gastric cancer tissues

BACKGROUND

Circular RNAs (circRNAs) are a special class of endogenous noncoding RNAs that have numerous biological functions in normal situation and diseases including cancers. However, the clinical significance of circRNAs in gastric cancer (GC) remains largely unknown. Here, we chose two representative circRNAs, hsa_circ_0067582 and hsa_circ_0005758, to investigate their clinical significance in GC patients.

METHODS

Using real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we explored the expression levels of hsa_circ_0067582 and hsa_circ_0005758 in tissues with different stages of gastric tumorigenesis. Then, the relationships between their expression levels and GC patients' clinicopathological factors were further investigated. Receiver operating characteristic (ROC) curves were established for evaluating diagnostic values of hsa_circ_0067582 and hsa_circ_0005758.

RESULTS

Compared with healthy control tissues, both hsa_circ_0067582 and hsa_circ_0005758 were significantly decreased in GC tissues. Besides, hsa_circ_0067582 expression was associated with GC patients' tissue CEA level (P <.001) and stages (P = .037); and hsa_circ_0005758 expression was relevant to tissue CEA level (P < .001) and perineural invasion (P = .048). The area under the ROC curve (AUC) of hsa_circ_0067582 was up to 0.671. The cutoff value was set at 10.61, with which the sensitivity and specificity were 55.2% and 75.0%, respectively. Similar to hsa_circ_0005758, the AUC of hsa_circ_0005758 was 0.721. The cutoff value was set at 10.20, with which the sensitivity and specificity were 75.0% and 67.7%, respectively.

CONCLUSION

These results showed that both hsa_circ_0067582 and hsa_circ_0005758 may play an important role in gastric carcinogenesis; and they may be potential indicators for GC diagnosis.

Sichong formula inhibits the proliferation and migration of human gastric cancer cells

Purpose

Traditional Chinese medicine (TCM) has gained increasing attention for the treatment of multiple chronic diseases, such as cancer. Here we aim to identify the antitumor activity of Sichong formula, a novel TCM, in human gastric cancer cells and investigate the underlying mechanisms.

Methods

The AGS and MKN45 gastric cancer cells were treated with Sichong formula at different concentrations. The proliferation rates were tested by CCK-8 and colony formation assays. Cell migration and invasion were tested by scratch and transwell assays. Gelatin zymography was used to detect the matrix metalloproteinase 9 (MMP9) activity in cell suspendents. Cell apoptosis was analyzed by Annexin V/PI staining and flow cytometry. The expression of interest proteins was tested by Western blot.

Results

Cell proliferation analysis indicated that Sichong formula inhibited cell viability of AGS and MKN45 cells in a dose- and time-dependent manner. The IC50 values were 240 μg/mL and 200 μg/mL for AGS and MKN45 cells, respectively. Furthermore, we found that Sichong formula could inhibit the invasion and migration of gastric cancer cells, which might be mediated by the downregulation of MMP9 activity. Flow cytometry results indicated that Sichong formula induced apoptosis in gastric cancer cells through upregulation of Bax/Bcl2 ratio and activation of caspase cascade. The results from Western blot indicated that Sichong formula resulted in cell autophagy and inactivation of AKT signaling pathway.

Conclusion

Our data suggest that Sichong formula inhibits the proliferation and migration and induces apoptosis in human gastric cancer cells. The inhibitory effect of Sichong formula was, at least partly, mediated by cell autophagy and AKT pathway.

Long non-coding RNA NKILA inhibits proliferation and migration of lung cancer via IL-11/STAT3 signaling

BACKGROUND

MicroRNAs (miRNAs) play an important role in the development and progression of lots of cancer. Non-small cell lung cancer (NSCLC) is all lung cancer except small cell lung cancer (SCLC). The most common non-small cell lung cancer types include squamous cell carcinoma, large cell carcinoma and adenocarcinoma, and some other common types. Increasing studies identified that a long non-coding RNA NKILA was negatively correlated with breast cancer metastasis while its clinical significance and potential role in non-small cell lung cancer (NSCLC) remain unclear. In the present study, we confirmed the function of lncRNA NKILA as well as the underlying mechanism in regulating the NSCLC.

METHODS

The expression of lncRNA NKILA was detected in both Lung cancer tissues and cell line including A549 and NCI-H1299 by quantitative real-time reverse transcription. A small interfering RNA (siRNA) that targeted NKILA was transfected into cells to inhibit the expression of NKILA. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and scratch experiments were performed to analyze the migration and proliferation of NCI-H1299 which were transfected with si-NKILA. Protein levels of genes that related with G0/G1 arrest markers p16, p21, and p27 markers were measured.

RESULTS

The expression of NKILA was significantly down regulated in lung cancer tissues when compared to matched normal tissue.

CONCLUSION

In summary, our results confirmed that low expression of lncRNA NKILA plays a role in the deterioration of NSCLC cells and this effect depends on IL-11/STAT3 signaling.

Long noncoding RNA: an emerging player in diabetes and diabetic kidney disease

Diabetic kidney disease (DKD) is among the most common complications of diabetes mellitus (DM), and remains the leading cause of end-stage renal diseases (ESRDs) in developed countries, with no definitive therapy yet available. It is imperative to decipher the exact mechanisms underlying DKD and identify novel therapeutic targets. Burgeoning evidence indicates that long non-coding RNAs (lncRNAs) are essential for diverse biological processes. However, their roles and the mechanisms of action remain to be defined in disease conditions like diabetes and DKD. The pathogenesis of DKD is twofold, so is the principle of treatments. As the underlying disease, diabetes per se is the root cause of DKD and thus a primary focus of therapy. Meanwhile, aberrant molecular signaling in kidney parenchymal cells and inflammatory cells may directly contribute to DKD. Evidence suggests that a number of lncRNAs are centrally involved in development and progression of DKD either via direct pathogenic roles or as indirect mediators of some nephropathic pathways, like TGF-β1, NF-κB, STAT3 and GSK-3β signaling. Some lncRNAs are thus likely to serve as biomarkers for early diagnosis or prognosis of DKD or as therapeutic targets for slowing progression or even inducing regression of established DKD. Here, we elaborated the latest evidence in support of lncRNAs as a key player in DKD. In an attempt to strengthen our understanding of the pathogenesis of DKD, and to envisage novel therapeutic strategies based on targeting lncRNAs, we also delineated the potential mechanisms of action as well as the efficacy of targeting lncRNA in preclinical models of DKD.

Integrating Bipartite Network Projection and KATZ Measure to Identify Novel CircRNA-Disease Associations

Accumulating biological experiments have shown that circRNAs are closely related to the occurrence and development of many complex human diseases. During recent years, the associations of circRNA with disease have caused more and more researchers to pay attention and to analyze their correlation mechanisms. However, experimental methods for determining the associations of circRNA with a particular disease are still expensive, difficult, and time consuming. Moreover, the available databases related to circRNA-disease correlations have only recently been updated, and only a few computational methods are constructed to predict potential circRNA-disease correlations. Taking into account the limitations of experimental studies, we develop a novel computational method, named IBNPKATZ, for predicting potential circRNA-disease associations, which integrates the bipartite network projection algorithm and KATZ measure. This model is based on the known circRNA-disease associations, combining circRNA similarity and disease similarity. Specifically, the circRNA similarity is derived from the average of the semantic similarity and the Gaussian interaction profile (GIP) kernel similarity of circRNA. Similarly, disease similarity is the mean of the semantic similarity and the GIP kernel similarity of disease. Furthermore, it is semi-supervised and does not require negative samples. Finally, IBNPKATZ achieves reliable AUC of 0.9352 in the leave-one-out cross validation, and case studies show that the circRNA-disease correlations predicted by our method can be successfully demonstrated by relevant experiments. The IBNPKATZ is expected to be a useful biomedical research tool for predicting potential circRNA-disease associations.

Exosomes, metastases, and the miracle of cancer stem cell markers

Cancer-initiating cells (CIC) are the driving force in tumor progression. There is strong evidence that CIC fulfill this task via exosomes (TEX), which modulate and reprogram stroma, nontransformed cells, and non-CIC. Characterization of CIC, besides others, builds on expression of CIC markers, many of which are known as metastasis-associated molecules. We here discuss that the linkage between CIC/CIC-TEX and metastasis-associated molecules is not fortuitously, but relies on the contribution of these markers to TEX biogenesis including loading and TEX target interactions. In addition, CIC markers contribute to TEX binding- and uptake-promoted activation of signaling cascades, transcription initiation, and translational control. Our point of view will be outlined for pancreas and colon CIC highly expressing CD44v6, Tspan8, EPCAM, claudin7, and LGR5, which distinctly but coordinately contribute to tumor progression. Despite overwhelming progress in unraveling the metastatic cascade and the multiple tasks taken over by CIC-TEX, there remains a considerable gap in linking CIC biomarkers, TEX, and TEX-initiated target modulation with metastasis. We will try to outline possible bridges, which could allow depicting pathways for new and expectedly powerful therapeutic interference with tumor progression.

The functions and oncogenic roles of CCAT1 in human cancer

In various human cancers, long non-coding RNAs (lncRNAs), a novel class of RNAs longer than 200 nucleotides without protein-coding potential, are implicated in a variety of biological processes, such as cell proliferation, invasion, metastasis, and apoptosis through regulation of gene expression at various levels including chromatin, splicing, transcriptional and post-transcriptional levels. However, the mechanisms underlying these are still elusive. Colon cancer-associated transcript 1(CCAT1) has received increased attention among those lncRNAs. Studies have shown high expression pattern and oncogenic role of CCAT1 in different types of cancer, and aberrant expression of CCAT1 has been involved in tumor-genesis, progression, metastasis, and patient survival via regulating different target genes and signaling pathways. In this review, we first introduce the concept, identification, and biological function of CCAT1; we then describe the mechanisms by which CCAT1 regulate the cancer proliferation and progression. In the last, we discuss emerging insights into the role of CCAT1 as potential biomarker and therapeutic target for novel treatment paradigms in cancer.

Long noncoding RNA DLX6-AS1 promotes tumorigenesis by modulating miR-497-5p/FZD4/FZD6/Wnt/β-catenin pathway in pancreatic cancer

Background

Long noncoding RNAs (lncRNAs) are abnormally expressed in various human tumors and play an important role in multiple tumorigeneses, including pancreatic cancer (PC).

Materials and methods

The present study was designed to evaluate the role of lncRNA DLX6-AS1 in tumorigenesis of PC. The expression of DLX6-AS1 and its effect on proliferation, apoptosis, migration, and invasion was investigated in vitro. Its effect on tumor growth and metastasis in vivo and its potential targets were also examined.

Results

We observed that DLX6-AS1 was highly expressed in PC tissues and PC cell lines, and was negatively correlated with the survival of PC patients. We found that overexpression of DLX6-AS1 promoted proliferation, migration, and invasion of PC cells, inhibited apoptosis, increased Bcl-2, cyclin D1, and MMP-2 expression, and decreased cleaved caspase 3, p27, and E-cadherin expression in PC cells. In addition, overexpression of DLX6-AS1 promoted PC growth by increasing tumor volume and weight and increasing the number of liver and lung metastatic foci. Knockdown of DLX6-AS1 showed an opposite effect in all the experiments. miR-497-5p was demonstrated to be a direct target of DLX6-AS1 and was regulated by DLX6-AS1. We also demonstrated that miR-497-5p targeted FZD4 and FZD6 and decreased their expression. miR-497-5p mimics also decreased the expression of FZD4, FZD6, and β-catenin; the expression of FZD4 or FZD6 was reversed by the overexpression of vectors FZD4 or FZD6, respectively, while the expression of β-catenin was reversed by either vector. Finally, the effect of DLX6-AS1 on proliferation, cell cycle, migration, invasion, and apoptosis of cells and expression of FZD4, FZD6, and β-catenin was neutralized by overexpression of vectors of miR-497-5p, FZD4, or FZD6, totally or partially.

Conclusion

Collectively, these findings suggested that DLX6-AS1/miR-497-5p/FZD4/FZD6/Wnt/β-catenin signaling pathway is involved in the pathogenesis of PC, and DLX6-AS1 could be a potential biomarker and target for PC treatment.

LncRNAs with miRNAs in regulation of gastric, liver, and colorectal cancers: updates in recent years

Long noncoding RNA (lncRNA) is a kind of RNAi molecule composed of hundreds to thousands of nucleotides. There are several major types of functional lncRNAs which participate in some important cellular pathways. LncRNA-RNA interaction controls mRNA translation and degradation or serves as a microRNA (miRNA) sponge for silencing. LncRNA-protein interaction regulates protein activity in transcriptional activation and silencing. LncRNA guide, decoy, and scaffold regulate transcription regulators of enhancer or repressor region of the coding genes for alteration of expression. LncRNA plays a role in cellular responses including the following activities: regulation of chromatin structural modification and gene expression for epigenetic and cell function control, promotion of hematopoiesis and maturation of immunity, cell programming in stem cell and somatic cell development, modulation of pathogen infection, switching glycolysis and lipid metabolism, and initiation of autoimmune diseases. LncRNA, together with miRNA, are considered the critical elements in cancer development. It has been demonstrated that tumorigenesis could be driven by homeostatic imbalance of lncRNA/miRNA/cancer regulatory factors resulting in biochemical and physiological alterations inside the cells. Cancer-driven lncRNAs with other cellular RNAs, epigenetic modulators, or protein effectors may change gene expression level and affect the viability, immortality, and motility of the cells that facilitate cancer cell cycle rearrangement, angiogenesis, proliferation, and metastasis. Molecular medicine will be the future trend for development. LncRNA/miRNA could be one of the potential candidates in this category. Continuous studies in lncRNA functional discrepancy between cancer cells and normal cells and regional and rational genetic differences of lncRNA profiles are critical for clinical research which is beneficial for clinical practice.

GHET1 acts as a prognostic indicator and functions as an oncogenic lncRNA in cervical cancer

Gastric carcinoma proliferation enhancing transcript 1 (GHET1) has been suggested to serve as a promising oncogenic lncRNA in various types of human cancer. However, the role of GHET1 remained unknown in cervical cancer. In our study, we found GHET1 expression was markedly elevated in cervical cancer tissue specimens and cell lines compared with adjacent normal cervical tissue specimens and human normal cervical cell line, respectively. Then, we found high expression of GHET1 is a useful biomarker to discriminate cervical cancer tissues from non-tumorous tissues, and associated with advanced clinical stage, lymph node metastasis, distant metastasis and poor histological grade in cervical cancer patients. The survival analysis showed high GHET1 expression was an independent unfavorable prognostic factor in cervical cancer patients. Knockdown of GHET1 expression markedly inhibits cervical cancer cell proliferation, migration, and invasion. The loss-of-function study indicated knockdown of GHET1 expression markedly inhibits cervical cancer cell proliferation, migration, and invasion. In conclusion, GHET1 acts as an oncogenic lncRNA in cervical cancer.

The lncRNA CCAT2 rs6983267 G allele is associated with decreased susceptibility to recurrent miscarriage

Genetics might play various roles in susceptibility to recurrent miscarriage, and previous studies suggest that some gene polymorphisms might be associated with abortion and breast cancer onset. Colon cancer-associated transcript 2 (CCAT2) is a novel long noncoding RNA (lncRNA) transcript that might be correlated with susceptibility to multiple cancers, including breast cancer. However, whether lncRNA CCAT2 polymorphisms are related to susceptibility to recurrent miscarriage is unclear. We genotyped two lncRNA CCAT2 polymorphisms (rs6983267 and rs3843549) in 248 patients with recurrent miscarriage and 392 controls through a TaqMan real-time polymerase chain reaction assay, and the strength of each association was evaluated via 95% confidence intervals (CIs) and odds ratios (ORs). Our results showed that the rs6983267 G allele in lncRNA CCAT2 was associated with decreased susceptibility to recurrent miscarriage (TG vs. TT: adjusted OR = 0.603; 95% CI = 0.420-0.866; p = 0.0062; GG/TG vs. TT: adjusted OR = 0.620; 95% CI = 0.441-0.873; p = 0.0061). The combined analysis of the two protective polymorphisms (rs3843549 AA and rs6983267 TG/GG) revealed that individuals with two unfavorable alleles exhibited a lower risk of recurrent miscarriage than those with no or only one unfavorable allele (adjusted OR = 0.531; 95% CI = 0.382-0.739). Moreover, the decreased risk associated with the two protective alleles was most obvious in women aged less than 35 years (OR = 0.551; 95% CI = 0.378-0.8803; p = 0.0019) and in women with two to three miscarriages (adjusted OR = 0.466; 95% CI = 0.318-0.683; p < 0.0001). In conclusion, our study indicates that the rs6983267G allele might contribute to a decreased risk of recurrent miscarriage in the South Chinese population.

Transcriptome sequencing profiles reveal lncRNAs may involve in breast cancer (ER/PR positive type) by interaction with RAS associated genes

To reveal novel lncRNAs and explore how could lncRNA affect the ER/PR positive type breast cancer, 16 different lncRNA transcriptomes (8 breast cancer tissues and 8 normal breast tissues) were successfully sequenced. In total, 8,954 high quality lncRNAs, including 5,516 lncRNAs reported in the previous studies and 3,438 novel lncRNAs, were annotated. The highest expressed lncRNAs were MALAT1, SCARNA10, RP11-206M11.7 and NEAT1, and the highest expressing mRNAs were RPL19, SCGB2A2, FTL and TMSB4 × . Of the 615 differentially expressed lncRNAs, 323 showed up regulated (P < 0.05) expression patterns in breast cancer, and 292 showed down regulated expression patterns. Of the 8,954 genes, 5,516 genes were upregulated in breast cancer, and 3,438 were downregulated. In total, the targets of 238 lncRNAs were confirmed by two lncRNA target prediction programs. Within these genes, Ras responsive element binding protein 1, Ras association domain family member 6, Ras association domain family member 8, Ras protein specific guanine nucleotide releasing factor 1and other 10 different Ras associated different expressed genes were predicted as targets of lncRNAs. These different expressed lncRNAs which could regulate the Ras gene families and ECM pathway may be another mechanism why the expression pattern of Ras genes changed in breast cancer. All these cancer-related genes (Ras genes) were annotated as targets of lncRNAs in the breast cancer transcriptome may provide us with a new way to understand the occurrence and development of breast cancer.

Long Intergenic Non-Protein-Coding RNA 01138 Accelerates Tumor Growth and Invasion in Gastric Cancer by Regulating miR-1273e

BACKGROUND The treatment and nursing of gastric cancer (GC) remains an enormous challenge in clinical practice. Understanding the potential mechanisms of the pathogenesis of GC would improve GC therapy. Long intergenic non-protein-coding RNA 01138 (LINC01138) was reported to promote the progression of hepatocellular carcinoma; however, whether it is involved in GC progression has been unclear. MATERIAL AND METHODS Expressions of LINC01138 and miR-1273e in GC tissues and cell lines were measured by qRT-PCR assay. The interaction between LINC01138 and miR-1273e was predicted by the online tool miRDB, verified by dual-luciferase reporter and RNA pulldown assays. Effects of LINC01138 knockdown or miR-1273e overexpression on cell viability, proliferation, apoptosis, invasion, and migration were evaluated by MTT, colony formation assay, flow cytometry, and Transwell assays. Target genes of miR-1273e were predicted by KEGG analysis, and involvement of the mitogen-activated protein kinase (MAPK) pathway was confirmed by qRT-PCR assay. RESULTS LINC01138 was increased but miR-1273e was decreased in GC tissues and cell lines. Knockdown of LINC01138 suppressed GC cell viability, proliferation, invasion, and migration, and promoted GC cell apoptosis. We demonstrated that LINC01138 contributed to GC progression by directly sponging and inhibiting miR-1273e. Moreover, the MAPK pathway was verified to participate in the promotive effects of LINC01138 on GC progression. CONCLUSIONS LINC01138 activated the MAPK signaling pathway by inhibiting miR-1273e to promote GC cell proliferation, invasion, and migration, and inhibit GC cell apoptosis, suggesting that the LINC01138/miR-1273e/MAPK axis is a promising therapeutic target for GC.

METTL3 Promotes the Proliferation and Mobility of Gastric Cancer Cells

Methyltransferase-like 3 (METTL3) was originally known to be responsible for N6-methyladenosine (m6A) modification of mRNA. Recent studies have found that METTL3 plays important roles in a variety of tumors by regulating the translation of oncogenes. However, the functional and regulating mechanisms of METTL3 in human gastric cancer have not yet been understood. Here we knocked down METTL3 in human gastric cancer cell lines, AGS and MKN45, by using shRNA transfection. RT-qPCR assay and western blotting verified the effectiveness of RNA interference on mRNA and protein levels, respectively. Then we found that METTL3 knockdown inhibited cell proliferation, migration and invasion in AGS and MKN45 cells. Moreover, METTL3 knockdown decreased Bcl2 and increased Bax and active Caspase-3 in gastric cancer cells, which suggested the apoptotic pathway was activated. Mechanistic investigation suggested that METTL3 led to inactivation of the AKT signaling pathway in human gastric cancer cells, including decreased phosphorylation levels of AKT and expression of down-stream effectors p70S6K and Cyclin D1. In conclusion, our study reveals that down-regulation of METTL3 inhibits the proliferation and mobility of human gastric cancer cells and leads to inactivation of the AKT signaling pathway, suggesting that METTL3 may be a potential target for the treatment of human gastric cancer.

Long Chain Non-Coding RNA (lncRNA) HOTAIR Knockdown Increases miR-454-3p to Suppress Gastric Cancer Growth by Targeting STAT3/Cyclin D1

BACKGROUND Gastric cancer is a common gastrointestinal tumor. The incidence and mortality of gastric cancer are very high. Therefore, it is important to study targeted drugs. Recent studies found long chain non-coding RNA (lncRNAs) and microRNAs (miRNAs) were abnormal in gastric cancer. MATERIAL AND METHODS We collected adjacent normal and cancer tissues of gastric cancer patients and measured HOTAIR, miR-454-3p, STAT3, and Cyclin D1 expression and analyzed the correlation with clinical status. We also measured AGS and SGC7901 cells proliferation rate of different groups by MTT assay, and we evaluated AGS and SGC7901 cell apoptosis and cell cycle by flow cytometry. In addition, we assessed the relative proteins expressions by WB assay. Finally, we explored the correlation between miR-454-3p and STAT3 by use of double luciferase reporter. RESULTS lncRNA HOTAIR was negatively correlated with miR-454-3p expression in gastric cancer tissues. lncRNA HOTAIR knockdown suppressed AGS and SGC7901, which are gastric cancer cell lines that promote cell proliferation by increasing cell apoptosis and keeping the cell cycle in G1 phase. In further mechanism research, we found that the STAT3 and Cyclin D1 proteins expressions were suppressed by lncRNA HOTAIR down-regulation in AGS and SGC7901 cells. CONCLUSIONS Our results suggest that lncRNA HOTAIR knockdown stimulates miR-454-3p expression to inhibit gastric cancer growth by depressing STAT3/Cyclin D1 activity.

Long non-coding RNA FLJ22763 is involved in the progression and prognosis of gastric cancer

Long noncoding RNAs (lncRNAs) play important roles in carcinogenesis. It is necessary to uncover the detailed pattern of comprehensive lncRNA expression in the genome during the development of gastric cancer (GC). We implemented lncRNA microarray analysis in 5 paired GC tissues to detect the lncRNA expression profile. Moreover, we set out to explore the biological function, clinical application and molecular basis of the aberrant lncRNA in GC. In addition, we used the high-throughput microarray to identify the target gene of the aberrant lncRNA. We found that FLJ22763, a novel lncRNA, had significantly lower expression in GC tissues. Decreased expression of FLJ22763 was positively correlated with a lower-level histological grade and the depth of invasion. The ectopic expression of lncRNA FLJ22763 significantly suppressed the biological malignant behavior of GC cells and inhibited xenograft tumor growth (both P < 0.001). Notably, FLJ22763 displayed a considerable predictive effect in the prognosis of GC (log-rank, P = 0.003). Furthermore, we found that FLJ22763 was negatively associated with ACLY, regulating the mRNA and protein levels of ACLY. Our findings suggested that FLJ22763 may act as a suppressor gene to regulate the expression of ACLY, and its down-expression may be an independent prognostic factor in patients with GC.

Methylation Patterns of Lys9 and Lys27 on Histone H3 Correlate with Patient Outcome in Gastric Cancer

BACKGROUND

Histone methylation has been considered as one of the epigenetic mechanisms of carcinogenesis and progression. Researches on the correlation between histone lysine methylation and gastric cancer (GC) will help in finding novel epigenetic biomarkers for monitoring cancers.

AIMS

The study detected the expression patterns of histone 3 lysine 9 dimethylation (H3K9me2), histone 3 lysine 9 trimethylation (H3K9me3), and histone 3 lysine 27 trimethylation (H3K27me3) in GC tissues and evaluated their clinical merit for GC patients.

METHODS

One hundred thirty-three paraffin-embedded GC samples were examined by immunohistochemistry for the histone markers: H3K9me2, H3K9me3, and H3K27me3. The relationship and clinicopathological significance of the three lysine methylations on histone H3 with GC were assessed by Paired t test, Chi-square test, Kaplan-Meier analysis with log-rank test, and Cox proportional hazard analyses.

RESULTS

Strong positive immunostaining of H3K9me2, H3K9me3, and H3K27me3 was observed in cancerous tissues than in their counterpart non-cancer tissues. Higher expression patterns of H3K9me2, H3K9me3, and H3K27me3 significantly related to differentiation degree, lymph nodes metastases, and pathological TNM staging in GC. The GC patients with low scoring of the three markers implied long survival period and best prognosis. In contrast, the patients' survival time was significantly shorter if their cancerous tissues presented high expression of the three markers.

CONCLUSIONS

H3K9me2, H3K9me3, and H3K27me3 expression patterns closely relate to clinicopathological features and may be the independent risk factors for the survival of GC patients. The combined pattern of the three markers rather than an individual marker is considered to more accurately evaluate the outcome of GC patients.

LncRNA SNHG16 Functions as an Oncogene by Sponging MiR-135a and Promotes JAK2/STAT3 Signal Pathway in Gastric Cancer

lncRNA can serve as a miRNA sponge and block the function of miRNA. High expression of lncRNA SNHG16 (small nucleolar RNAhostgene16) was discovered in gastric cancer (GC) and many other tumors. However, the mechanism of SNHG16 in GC is still unclear. In this research, we detected the expression level of SNHG16 in GC tissues and cell lines by qRT-PCR and FISH assay. RIP and Dual Luciferase Reporter Assay revealed that miR-135a is a target of SNHG16. SNHG16 gene knockdown experiment indicated that the expression level of SNHG16 can influence GC cells proliferation, colony formation, invasion ability and apoptosis in a miR-135a dependent manner. Western Blot assay showed that knockdown of SNHG16 decreased the expression of JAK2 and p-STAT3 in GC cells while miR-135a can offset the facilitated impact. Then the expression level of SNHG16 and miR-135a in the si-STAT3 GC cells was detected by qRT-PCR and the results showed that SNHG16 may be a target gene of p-STAT3. Collectively, it was suggested that SNHG16 can serve as a miR-135a sponge and block the function of miR-135a in JAK2/STAT3 pathway.

lncRNA GHET1 knockdown suppresses breast cancer activity in vitro and in vivo

Long non-coding RNA gastric carcinoma high-expressed transcript 1 (lncRNA GHET1) is highly expressed in many tumors. The aim of the present study was to determine whether GHET1 inhibition decreases growth and metastasis of MCF-7 breast cancer cells by modulating epidermal growth factor receptor (EGFR) expression. In vitro, lncRNA GHET1 knockdown suppressed cell proliferation, migration, and invasion and enhanced cell apoptosis by maintaining MCF-7 cells in the G1 phase of the cell cycle. Furthermore, lncRNA GHET1 knockdown reduced the expression of EGFR and related proteins. Treatment of mice with a GHET1 inhibitor prevented tumor growth in vivo. The results indicate that lncRNA GHET1 inhibition directly suppresses EGFR expression, significantly inhibiting the downstream PI3K/AKT/Cyclin D1/MMP2/9 pathway. This mechanism may underlie the suppression of breast cancer cell activities including proliferation, migration, and invasion. In conclusion, lncRNA GHET1 knockdown suppresses tumor growth and metastasis by suppressing the activity of EGFR and downstream pathways.

MALAT1: a potential biomarker in cancer

Purpose

The research of long non-coding RNAs (lncRNAs) has become a new passion with the discovery of abundant new lncRNAs and extensive investigation of their roles in various diseases, especially in cancers. Metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) emerges as a hotspot, which has been reported to be involved in dysregulation of cell signaling and closely correlated with cancer development, progression, and response to therapy. This review is a brief update of the current knowledge related to the role of MALAT1 in cancer-associated molecular pathways and pathophysiology and possible determinants for MALAT1 to function as a biomarker, aiming to stimulate the basic investigation of lncRNA MALAT1 as well as its translation to clinical applications.

Methods

We have selected vast literature from electronic databases including studies associated with its clinical significance and the pivotal functions in cancer processes such as cell proliferation, apoptosis, metastasis, immunity, angiogenesis, and drug resistance.

Results

Studies have shown that aberrant expression of MALAT1 is related to cancer pathophysiology with the potential to be translated clinically and MALAT1 can regulate cancer processes by interacting with molecules, such as proteins, RNAs and DNAs, and further altering different signal pathways.

Conclusion

MALAT1 lncRNA promises to be a potential biomarker for cancer diagnosis as well as prognosis. Additionally, it might be a therapeutic target for human cancers.

Long noncoding RNA DGCR5 suppresses gastric cancer progression by acting as a competing endogenous RNA of PTEN and BTG1

Long noncoding RNA (lncRNA) DiGeorge syndrome critical region gene 5 (DGCR5) has been reported to correlate with a variety of cancers, with its expression pattern and potential mechanism not clarified in gastric cancer (GC). In this study, we demonstrated that DGCR5 was downregulated in cancerous tissues and plasma samples from patients with GC, and its downregulation was associated with advanced TNM stage and positive lymphatic metastasis. Plasma DGCR5 had an area under the receiver operating characteristic curve (AUC) of 0.722 for diagnosis of GC. Gain- and loss-of-function of DGCR5 revealed that DGCR5 functioned as a competing endogenous RNA for miR-23b to suppress GC cell proliferation, invasion and migration, and facilitate apoptosis by regulating PTEN and BTG1 in vitro. Furthermore, the overexpression of DGCR5 suppressed tumor growth, and inhibited the expression of miR-23b and proliferation antigen Ki-67, but increased the expression of PTEN and BTG1 in vivo. In conclusion, our results show that DGCR5 is a tumor-suppressive lncRNA that regulates PTEN and BTG1 expression through directly binding to miR-23b. This mechanism may contribute to a better understanding of GC pathogenesis and provide a potential therapeutic strategy for GC.

LONG-NONCODING RNAs in gastroesophageal cancers

Despite continuing improvements in multimodal therapies, gastro-esophageal malignances remain widely prevalent in the population and is characterized by poor overall and disease-free survival rates. Due to the lack of understanding about the pathogenesis and absence of reliable markers, gastro-esophageal cancers are associated with delayed diagnosis. The increasing understanding about cancer's molecular landscape in the recent years, offers the possibility of identifying 'targetable' molecular events and in particular facilitates novel treatment strategies and development of biomarkers for early stage diagnosis. At least 98% of our genome is actively transcribed into non-coding RNAs encompassing long non-coding RNAs (lncRNAs) constituted of transcripts longer than 200 nucleotides with no protein-coding capacity. Many studies have demonstrated that lncRNAs are functional genomic elements playing pivotal roles in main oncogenic processes. LncRNA can act at multiple levels developing a complex molecular network that can modulate directly or indirectly the expression of genes involved in tumorigenesis. In this review, we focus on lncRNAs as emerging players in gastro-esophageal carcinogenesis and critically assess their potential as reliable noninvasive biomarkers and in next generation targeted therapies.

Long noncoding RNA H19 mediated the chemosensitivity of breast cancer cells via Wnt pathway and EMT process

Background

Breast cancer is still one of the major public health burdens worldwide, although there is tremendous progress in early diagnosis and treatment of breast cancer. Tamoxifen was one of the most popular endocrine therapies for early-stage estrogen receptor (ER) + breast cancer patients. However, a high incidence of drug resistance develops along with poor prognosis in breast cancer. Currently, long noncoding RNAs (lncRNAs) are emerging and are well suited to play a role in the development of cancer and tamoxifen resistance. However, there is little reported about the relationship of breast cancer resistance to tamoxifen and lncRNA H19. Here, we validated that lncRNA H19 was highly expressed in breast cancer especially in patients with late stage (III and IV), compared to normal tissues and early stage cancers (I and II).

Methods

Quantitative polymerase chain reaction (qPCR) was utilized for comparison of lncRNA H19 expression level in breast cancers with different stages. qPCR and Western blotting were used to detect gene and protein, respectively.

Results

We found that lncRNA H19 expression level manipulated breast cancer cell proliferation both in parental breast cancer cell lines and tamoxifen-resistant cell lines. Knockdown of lncRNA H19 elevated tamoxifen sensitivity for promoting cell growth and inhibiting apoptosis in tamoxifen-resistant breast cancer cells. Moreover, knockdown of H19 inhibited Wnt pathway and epithelia–mesenchymal transition in tamoxifen-resistance breast cancer cells.

Conclusion

Taken together, the results of this study provided the evidence for H19 in regulating tamoxifen-resistant breast cancer and might provide novel options in the future treatment of tamoxifen-resistance breast cancer patients.

Long noncoding RNA GHET1 in human cancer

LncRNAs are a group of noncoding RNAs that are >200 nucleotides in length. These RNAs have no significant protein-coding potential due to the lack of obvious open reading frames. To date, accumulating evidence has demonstrated that dysregulation of lncRNAs exhibits indispensable roles in the pathological processes of human cancers. These RNAs function as either oncogenes or tumor suppressor genes to regulate proliferation, migration and invasion of cancer cells. GHET1, a prominent oncogenic lncRNA, is highly expressed in diverse malignancies. Furthermore, GHET1 performs key functions in carcinogenesis and progression, suggesting that GHET1 is expected to be a prospective biomarker or therapeutic target for cancers. In this review, we provide a summary of the current evidence concerning the biological functions, underlying mechanisms and clinical significance of GHET1 during tumor development.

LASSO‑based Cox‑PH model identifies an 11‑lncRNA signature for prognosis prediction in gastric cancer

The present study aimed to identify a long non-coding (lnc) RNAs-based signature for prognosis assessment in gastric cancer (GC) patients. By integrating gene expression data of GC and normal samples from the National Center for Biotechnology Information Gene Expression Omnibus, the EBI ArrayExpress and The Cancer Genome Atlas (TCGA) repositories, the common RNAs in Genomic Spatial Event (GSE) 65801, GSE29998, E-MTAB-1338, and TCGA set were screened and used to construct a weighted correlation network analysis (WGCNA) network for mining GC-related modules. Consensus differentially expressed RNAs (DERs) between GC and normal samples in the four datasets were screened using the MetaDE method. From the overlapped lncRNAs shared by preserved WGCNA modules and the consensus DERs, an lncRNAs signature was obtained using L1-penalized (lasso) Cox-proportional hazard (PH) model. LncRNA-mRNA networks were constructed for these signature lncRNAs, followed by functional annotation. A total of 14,824 common mRNAs and 2,869 common lncRNAs were identified in the 4 sets and 5 GC-associated WGCNA modules were preserved across all sets. MetaDE method identified 1,121 consensus DERs. A total of 50 lncRNAs were shared by preserved WGCNA modules and the consensus DERs. Subsequently, an 11-lncRNA signature was identified by LASSO-based Cox-PH model. The lncRNAs signature-based risk score could divide patients into 2 risk groups with significantly different overall survival and recurrence-free survival times. The predictive capability of this signature was verified in an independent set. These signature lncRNAs were implicated in several biological processes and pathways associated with the immune response, the inflammatory response and cell cycle control. The present study identified an 11-lncRNA signature that could predict the survival rate for GC.

The FENDRR/miR-214-3P/TET2 axis affects cell malignant activity via RASSF1A methylation in gastric cancer

To explore the effect of fetal-lethal non-coding developmental regulatory RNA (FENDRR) in the initiation and progression of gastric cancer (GC). We detected the levels of FENDRR, microRNA-214-3p (miR-214-3p), and ten-eleven-translocation (TET2) in GC tissues and GC cell lines. In addition, we evaluated the location of FENDRR in GC cell lines by fluorescence in situ hybridization (FISH). Cell proliferation and apoptosis were measured by CCK-8 and Hoechst staining assays. Methylation-specific PCR assay (MSP) was used to evaluate the methylation status of ras-association domain family 1A (RASSF1A). We also observed the direct binding of miR-214-3p on FENDRR by dual-luciferase activity assay in GC cells. FENDRR and TET2 expressions were significantly down-regulated and miR-214-3p was up-regulated in gastric cancer tissues compared to adjacent unaffected tissues. In addition, RASSF1A was hypermethylated in gastric cancer tissues compared to adjacent tissues. The expressions of all the three indicators were influenced by differentiation of tumor, TNM stage of tumors, and lymph node metastasis in patients with GC. A gastric cancer cell line with low FENDRR expression compared to a high FENDRR expressing cell line showed again increased miR-214-3p expression, decreased TET2 and RASSF1A expressions, and RASSF1A hypermethylation, resulting in decreased apoptosis and increased proliferation. Furthermore, we observed a negative correlation between FENDRR and miR-214-3p in GC. The FENDRR/miR-214-3P/TET2 axis plays a critical role in GC progress via methylation of RASSF1A.

Chicken GHR antisense transcript regulates its sense transcript in hepatocytes

An increasing number of evidences indicated that long noncoding RNAs (LncRNAs) regulate a variety of biological progresses via different mechanisms. Our previous study had identified a chicken growth hormone receptor (GHR) antisense transcript (GHR-AS) which regulated GHR sense transcript (GHR-S) in LMH cells. In the present study, roles of GHR-AS and its regulatory mechanism were analyzed in chicken hepatocytes. The expression patterns of liver GHR-S, GHR-AS and Let-7b ascended with the development of chicken. The hepatocytes proliferation was promoted and more cells entered into DNA synthesis (S) phase when GHR-AS was overexpressed while the cell proliferation was slowed and fewer cells were in S phase when GHR-AS was interfered. Meanwhile, the GHR-S increased when we overexpressed GHR-AS while it reduced when GHR-AS was inhibited. The S1 Nuclease protection assay indicated that GHR-S and GHR-AS formed RNA duplex via GHR-S 3' untranslation regon (3'UTR). In hepatocytes or LMH cells, the half-time of GHR-S showed a delayed trend when GHR-AS or GHR-AS 5' untranslation regon (5'UTR) was overexpressed. Furthermore, the level of GHR-S can be decreased by Let-7b mimics whereas it was partially rescued when co-transfected pGHR-AS or pGHR-AS 5'UTR with Let-7b mimics. Based on our findings, GHR-AS affected hepatocytes proliferation and improved GHR-S stability possibly by forming RNA duplex between GHR-S and GHR-AS, competing with Let-7b.

LncRNA TINCR is associated with clinical progression and serves as tumor suppressive role in prostate cancer

Introduction

Terminal differentiation-induced non-coding RNA (TINCR) has been suggested to have aberrant expression in multiple human cancers, and functions as tumor suppressor or promoter in various types of human tumors depending on the specific cancer types. The expression status and biological function of TINCR in prostate cancer is still unknown.

Materials and methods

In our study, we detected TINCR expression in prostate cancer tissue samples and cell lines, and analyzed the association between TINCR expression and clinical parameters in 160 prostate cancer patients. Moreover, we conducted gain-of-function and loss-of-function studies in prostate cancer cell to explore the biological function and molecular mechanism of TINCR.

Results

In our results, low-expression TINCR was observed in prostate cancer, and correlated with advanced clinical T stage, lymph node involvement, distant metastasis, high Gleason score and poor prognosis in prostate cancer patients. Moreover, levels of TINCR expression were negatively associated with TRIP13 mRNA and protein expressions in prostate cancer tissues, and negatively regulated the TRIP13 mRNA and protein expressions in prostate cancer cell lines. TINCR inhibits prostate cancer cell proliferation, migration and invasion via suppressing TRIP13 expression.

Conclusion

TINCR plays a tumor suppressive role in regulating prostate cancer cell proliferation, migration and invasion through modulating TRIP13 expression.

Knockdown of long non-coding RNA ANRIL inhibits tumorigenesis in human gastric cancer cells via microRNA-99a-mediated down-regulation of BMI1

Long non-coding RNA antisense non-coding RNA in the INK4 locus (ANRIL) has been reported to promote tumorigenesis via regulating microRNA (miR)-99a in gastric cancer cells. However, the role of each component involved in it is still not well understood. This study aimed to verify the role of ANRIL in gastric cancer as well as the underlying mechanisms. ANRIL levels in clinical gastric cancer tissues and cell lines were tested by qPCR. Effects of ANRIL silence on cell viability, migration and invasion, apoptosis, and miR-99a expression in MKN-45 and SGC-7901 cells were measured using CCK-8, Transwell assay, flow cytometry, and qPCR assays, respectively. Then, effects of miR-99a inhibition on ANRIL-silenced cells were evaluated. B-lymphoma Mo-MLV insertion region 1 (BMI1) expression, after abnormal expression of ANRIL and miR-99a, was determined. Finally, expression of key proteins in the apoptotic, Notch, and mTOR pathways was assessed. ANRIL level was elevated in gastric cancer tissues and cell lines. Knockdown of ANRIL suppressed cell viability, migration, and invasion, and increased apoptosis through up-regulating miR-99a. Furthermore, ANRIL silence down-regulated BMI1 via up-regulating miR-99a. BMI1 silence down-regulated Bcl-2 and key kinases in the Notch and mTOR pathways and up-regulated p16 and cleaved caspases. We verified the tumor suppressive effects of ANRIL knockdown in gastric cancer cells via crosstalk with miR-99a. Together, we provided a novel regulatory mechanism for ANRIL in gastric cancer, in which ANRIL silence down-regulated BMI1 via miR-99a, along with activation of the apoptotic pathway and inhibition of the Notch and mTOR pathways.

Prognostic value of long noncoding RNAs in gastric cancer: a meta-analysis

Background

In the last few years, accumulating evidence has indicated that numerous long noncoding RNAs (lncRNAs) are abnormally expressed in gastric cancer (GC) and are associated with the survival of GC patients. This study aimed to conduct a meta-analysis on 19 lncRNAs (AFAP1 antisense RNA 1 [AFAP1-AS1], CDKN2B antisense RNA 1 [ANRIL], cancer susceptibility 15 [CASC15], colon cancer associated transcript 2 [CCAT2], gastric adenocarcinoma associated, positive CD44 regulator, long intergenic noncoding RNA [GAPLINC], H19, imprinted maternally expressed transcript [H19], HOX transcript antisense RNA [HOTAIR], HOXA distal transcript antisense RNA [HOTTIP], long intergenic non-protein coding RNA 673 [LINC00673], metastasis-associated lung adenocarcinoma transcript 1 [MALAT1], maternally expressed 3 [MEG3], promoter of CDKN1A antisense DNA damage activated RNA [PANDAR], Pvt1 oncogene [PVT1], SOX2 overlapping transcript [Sox2ot], SPRY4 intronic transcript 1 [SPRY4-IT1], urothelial cancer associated 1 [UCA1], X inactive specific transcript [XIST], ZEB1 antisense RNA 1 [ZEB1-AS1] and ZNFX1 antisense RNA 1 [ZFAS1]) to systematically estimate their prognostic value in GC.

Methods

The qualified literature was systematically searched in PubMed, Web of Science, Embase and Cochrane Database of Systematic Reviews (up to March 16, 2018), and one meta-analysis relating to the relationship between lncRNA expression and overall survival (OS) of GC patients was performed. The only evaluation criterion of survival results was OS.

Results

A total of 6,095 GC patients and 19 lncRNAs from 51 articles were included in the present study. Among the listed 19 lncRNAs, 18 lncRNAs (other than SPRY4-IT1) showed a significantly prognostic value (P<0.05).

Conclusion

This meta-analysis suggested that the abnormally expressed lncRNAs (AFAP1-AS1, ANRIL, CASC15, CCAT2, GAPLINC, H19, HOTAIR, HOTTIP, LINC00673, MALAT1, MEG3, PANDAR, PVT1, Sox2ot, UCA1, XIST, ZEB1-AS1 and ZFAS1) were significantly associated with the survival of GC patients, among which AFAP1-AS1, CCAT2, LINC00673, PANDAR, PVT1, Sox2ot, ZEB1-AS1 and ZFAS1 were strong candidates in predicting the prognosis of GC patients.

Long intergenic non-protein coding RNA 1006 used as a potential novel biomarker of gastric cancer

BACKGROUND

Accumulating evidences have shown that long non-coding RNAs (lncRNAs), longer than 200 nucleotides in length, play a crucial role in cancer occurrence and development. However, the relationships between most lncRNAs and gastric carcinogenesis remain poorly understood.

OBJECTIVE

To explore the diagnostic value of one typical lncRNA, long intergenic non-protein coding RNA 1006 (LINC01006), in gastric cancer.

METHODS

First, real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to determine the expression levels of LINC01006 in various gastric tissues from gastric cancer patients, healthy controls, and gastric dysplasia. Next, the correlation between LINC01006 expression levels and clinicopathological features of patients with gastric cancer was assessed. Finally, the relative levels of LINC01006 in gastric cancer cell lines comparing to normal gastric epithelial cell line were analyzed.

RESULTS

LINC01006 levels in cancer tissues were significantly lower than those in adjacent normal tissues (P< 0.001) and healthy control tissues (P< 0.001). Its expression was associated with age (P= 0.013), tumor location (P= 0.022), tumor size (P= 0.030), and venous invasion (P= 0.018). Moreover, expression of LINC01006 was downregulated in two gastric cancer cell lines, MGC-803 (P< 0.05) and AGS (P< 0.001) compared to normal gastric epithelial cell line GES-1.

CONCLUSIONS

All the data implied that LINC01006 may be a novel biomarker for gastric cancer.

Transcriptome-wide analysis of alternative mRNA splicing signature in the diagnosis and prognosis of stomach adenocarcinoma

Alternative mRNA splicing (AS) contributes greatly to expanding the diversity and function of the proteome. Increasing evidence has suggested that dysregulation of mRNA splicing may be associated with various types of cancer. In the present study, RNA sequencing data were used to investigate alterations to the global mRNA splicing landscape of cellular genes from 452 stomach adenocarcinoma (STAD) tissues available in The Cancer Genome Atlas. Seven types of AS events, including the profiles of exon skipping events, were analyzed using SpliceSeq software. A total of 60,754 AS events in 10,611 genes were detected, more than half of which were exon skipping events. The AS events were compared between 415 STAD tissues and 37 normal tissues, and 3,895 differentially spliced cancer-specific events were identified. In addition, the association of the AS events with the overall survival of 373 STAD patients was analyzed. Multivariate Cox regression analysis revealed that prognosis prediction models based on the AS events with clinical parameters had an excellent performance in predicting the survival of STAD patients. This study provides a comprehensive portrait of global changes in mRNA splicing signatures that occur in gastric cancer. These results allowed the identification of a core set of AS in gastric cancer and indicated that AS events may serve as prognostic indicators.

Long non-coding RNA AK096174 promotes cell proliferation and invasion in gastric cancer by regulating WDR66 expression

Gastric cancer (GC) is one of the major causes of cancer deaths worldwide; however, the mechanism of carcinogenesis is complex and poorly understood. Long non-coding RNA (lncRNA) has been reported to be involved in the development of multiple cancers. Here, we identified a novel lncRNA, AK096174, which was up-regulated and associated with tumorigenesis, tumor size, metastasis, and poor prognosis in GC. Our data showed that AK096174 was highly expressed in the GC tissues and cell lines (SGC-7901, AGS, BGC-823, MGC-803), and patients with higher AK096174 expression had a poorer prognosis and shorter overall survival (OS). AK096174 knockdown inhibited the proliferation, migration, and invasiveness in SGC-7901 and BGC-823 cells, whereas AK096174 overexpression had the promoting effects. Furthermore, mechanistic investigation showed that AK096174 positively correlated with the expression of WD repeat-containing protein 66 (WDR66) gene at the translational level. Knockdown of WRD66 attenuated the positive impact of AK096174 in GC cells. The findings of the present study establish a function for AK096174 in GC progression and suggest it may serve as a potential target for GC therapy in the future.

Identification and functional annotation of metabolism-associated lncRNAs and their related protein-coding genes in gastric cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) play important roles in carcinogenesis. However, the roles of metabolism-associated lncRNAs in cancers are still unclear.

METHODS

A microarray of metabolism-associated lncRNAs was used to detect their expression patterns between gastric cancer and paired nontumorous tissues. Its results and gastric cancer differential gene expression data from public databases were used to screen the metabolic pathway-associated lncRNAs. A metabolic network with microRNAs (miRNAs), lncRNAs, and protein-coding genes was further constructed. Finally, the expression of TOPORS antisense RNA 1 (TOPORS-AS1), a screened highly expressed lncRNA and its associated protein-coding gene, NADH: ubiquinone oxidoreductase subunit B6 (NDUFB6), were verified by reverse transcription polymerase chain reaction.

RESULTS

A total of eight upregulated and one downregulated lncRNAs and 25 upregulated and 20 downregulated protein-coding genes were found to be involved in metabolism in gastric cancer. Within the lncRNAs-miRNAs-mRNAs metabolic network, 78 miRNA-target links, 546 positive coexpression relationships, and 191 protein-protein interactions were found. The expression of TOPORS-AS1 and its associated gene, NDUFB6 in gastric cancer tissues was significantly lower than that in adjacent nontumor tissues. Moreover, NDUFB6 expression was associated with the invasion and distal metastasis of gastric cancer.

CONCLUSIONS

The metabolism-associated lncRNAs play important roles in the occurrence of gastric cancer.

ZFPM2-AS1, a novel lncRNA, attenuates the p53 pathway and promotes gastric carcinogenesis by stabilizing MIF

Long non-coding RNAs (lncRNAs) are implicated to be involved in the pathogenesis of many cancers. Herein we report on our discovery of a novel lncRNA, ZFPM2 antisense RNA 1 (ZFPM2-AS1), and its critical role in gastric carcinogenesis. ZFPM2-AS1 expression in gastric cancer specimens was analyzed using Gene Expression Omnibus data set and validated in 73 paired gastric tumor and normal adjacent gastric tissue specimens using qRT-PCR. The effect of ZFPM2-AS1 expression on proliferation and apoptosis in gastric cancer cells was assessed by altering its expression in vitro and in vivo. Mechanistic investigation was carried out using cell and molecular biological approaches. ZFPM2-AS1 expression was higher in gastric tumors than in normal gastric tissue. Also, increased ZFPM2-AS1 expression in gastric cancer specimens was associated with tumor size, depth of tumor invasion, differentiation grade, and TNM stage. High ZFPM2-AS1 expression predicted markedly reduced overall and disease-free survival in gastric cancer patients. Functional experiments demonstrated that ZFPM2-AS1 expression promoted proliferation and suppressed apoptosis of gastric cancer cells in vitro and promoted tumor growth in vivo. This effect is associated with attenuated nuclear translocation of p53. Mechanistic experiments demonstrated that tumor-activated ZFPM2-AS1 could bind to and protect the degradation of macrophage migration inhibitory factor (MIF), a potent destabilizer of p53. Knockdown of MIF expression diminished ZFPM2-AS1's impact on p53 expression in gastric cancer cells. Our findings demonstrated that ZFPM2-AS1 regulates gastric cancer progression and revealed a novel ZFPM2-AS1/MIF/p53 signaling axis, shedding light on the molecular mechanisms underlying the tumorigenicity of certain malignant gastric cells.

HOTAIR gene polymorphisms contribute to increased neuroblastoma susceptibility in Chinese children

BACKGROUND

Neuroblastoma is the most frequently diagnosed extracranial solid tumor in children. Previous studies have shown that single-nucleotide polymorphisms in some genes are associated with the risk of multiple cancers, including neuroblastoma. Although Hox transcript antisense intergenic RNA (HOTAIR) gene polymorphisms have been investigated in a variety of cancers, to the authors' knowledge the relationships between HOTAIR gene polymorphisms and neuroblastoma susceptibility have not been reported to date. The objective of the current study was to evaluate the correlation between HOTAIR gene polymorphisms and neuroblastoma risk in Chinese children.

METHODS

The authors genotyped 6 polymorphisms (rs920778 A>G, rs12826786 C>T, rs4759314 A>G, rs7958904 G>C, rs874945 C>T, and rs1899663 C>A) of the HOTAIR gene in 2 Chinese populations including 393 neuroblastoma cases and 812 healthy controls. The strength of the associations was evaluated using odds ratios and 95% confidence intervals. Further stratification analyses were conducted to explore the association between the HOTAIR gene polymorphisms rs12826786 C>T, rs874945 C>T, and rs1899663 C>A with neuroblastoma susceptibility in terms of age, sex, clinical stage of disease, and sites of origin.

RESULTS

The authors found that the rs12826786 C>T (P =.013), rs874945 C>T (P =.020), and rs1899663 C>A (P =.029) polymorphisms were significantly associated with increased neuroblastoma risk. In stratification analyses, these associations were more predominant in females and among patients with tumor in the retroperitoneal region or mediastinum. The remaining 3 polymorphisms were not found to be related to neuroblastoma susceptibility.

CONCLUSIONS

The results of the current study verified that HOTAIR gene polymorphisms are associated with increased neuroblastoma risk and suggest that HOTAIR gene polymorphisms might be a potential biomarker for neuroblastoma susceptibility. Cancer 2018;124:2599-606. © 2018 American Cancer Society.

Endogenous Control Mechanisms of FAK and PYK2 and Their Relevance to Cancer Development

Focal adhesion kinase (FAK) and its close paralogue, proline-rich tyrosine kinase 2 (PYK2), are key regulators of aggressive spreading and metastasis of cancer cells. While targeted small-molecule inhibitors of FAK and PYK2 have been found to have promising antitumor activity, their clinical long-term efficacy may be undermined by the strong capacity of cancer cells to evade anti-kinase drugs. In healthy cells, the expression and/or function of FAK and PYK2 is tightly controlled via modulation of gene expression, competing alternatively spliced forms, non-coding RNAs, and proteins that directly or indirectly affect kinase activation or protein stability. The molecular factors involved in this control are frequently deregulated in cancer cells. Here, we review the endogenous mechanisms controlling FAK and PYK2, and with particular focus on how these mechanisms could inspire or improve anticancer therapies.

Expression of microRNAs and IRAK1 pathway genes are altered in gastric cancer patients with Helicobacter pylori infection

Gastric cancer (GC) is among the most common cancer types in the world and one of the most lethal gastrointestinal cancers. MicroRNAs (miRNAs) can be of great importance in the early detection of GC. This study aimed to investigate some miRNAs and the genes involved in IRAK1 pathways in the serum of GC patients with Helicobacter pylori (H. pylori) infections compared to the control group. Total RNA was extracted from the serum of GC patients with H. pylori infection and healthy volunteers. The expression levels of miRNAs and the genes were assessed using Real time RT-PCR with specific primers. Our data showed that miR-146, miR-375, and Let-7 were down-regulated and miR-19 and miR-21 were up-regulated in GC patients with H. pylori infection. Other genes involved in the pathways such as RAS, MYC, NFKB, JUN, TRAF6, and IRAK4 were overexpressed; while the expression of PTEN gene was decreased compared to the control group. Expression of miRNAs and IRAK1 pathway genes are altered in patients with GC and H. pylori infection. This suggests a potential role for the above-mentioned miRNAs and genes in the diagnosis of GC.