Long non-coding RNA GATA6-AS1 is mediated by N6-methyladenosine methylation and inhibits the proliferation and metastasis of gastric cancer

BACKGROUND Through experimental research on the biological function of GATA6-AS1,it was confirmed that GATA6-AS1 can inhibit the proliferation,invasion,and migration of gastric cancer cells,suggesting that GATA6-AS1 plays a role as an anti-oncogene in the occurrence and development of gastric cancer.Further experi-ments confirmed that the overexpression of fat mass and obesity-associated protein(FTO)inhibited the expression of GATA6-AS1,thereby promoting the occurrence and development of gastric cancer.AIM To investigate the effects of GATA6-AS1 on the proliferation,invasion and migration of gastric cancer cells and its mechanism of action.METHODS We used bioinformatics methods to analyze the Cancer Genome Atlas(https://portal.gdc.cancer.gov/.The Cancer Genome Atlas)and download expression data for GATA6-AS1 in gastric cancer tissue and normal tissue.We also constructed a GATA6-AS1 lentivirus overexpression vector which was transfected into gastric cancer cells to investigate its effects on proliferation,migration and invasion,and thereby clarify the expression of GATA6-AS1 in gastric cancer and its biological role in the genesis and development of gastric cancer.Next,we used a database(http://starbase.sysu.edu.cn/starbase2/)to analysis GATA6-AS1 whether by m6A methylation modify regulation and predict the methyltransferases that may methylate GATA6-AS1.Furthermore,RNA immunoprecipitation experiments confirmed that GATA6-AS1 was able to bind to the m6A methylation modification enzyme.These data allowed us to clarify the ability of m6A methylase to influence the action of GATA6-AS1 and its role in the occurrence and development of gastric cancer.RESULTS Low expression levels of GATA6-AS1 were detected in gastric cancer.We also determined the effects of GATA6-AS1 overexpression on the biological function of gastric cancer cells.GATA6-AS1 had strong binding ability with the m6A demethylase FTO,which was expressed at high levels in gastric cancer and negatively correlated with the expression of GATA6-AS1.Following transfection with siRNA to knock down the expression of FTO,the expression levels of GATA6-AS1 were up-regulated.Finally,the proliferation,migration and invasion of gastric cancer cells were all inhibited following the knockdown of FTO expression.CONCLUSION During the occurrence and development of gastric cancer,the overexpression of FTO may inhibit the expression of GATA6-AS1,thus promoting the proliferation and metastasis of gastric cancer.

Non-coding RNAs in acute ischemic stroke:from brain to periphery

Acute ischemic stroke is a clinical emergency and a condition with high morbidity,mortality,and disability.Accurate predictive,diagnostic,and prognostic biomarkers and effective therapeutic targets for acute ischemic stroke remain undetermined.With innovations in high-throughput gene sequencing analysis,many aberrantly expressed non-coding RNAs(ncRNAs)in the brain and peripheral blood after acute ischemic stroke have been found in clinical samples and experimental models.Differentially expressed ncRNAs in the post-stroke brain were demonstrated to play vital roles in pathological processes,leading to neuroprotection or deterioration,thus ncRNAs can serve as therapeutic targets in acute ischemic stroke.Moreover,distinctly expressed ncRNAs in the peripheral blood can be used as biomarkers for acute ischemic stroke prediction,diagnosis,and prognosis.In particular,ncRNAs in peripheral immune cells were recently shown to be involved in the peripheral and brain immune response after acute ischemic stroke.In this review,we consolidate the latest progress of research into the roles of ncRNAs(microRNAs,long ncRNAs,and circular RNAs)in the pathological processes of acute ischemic stroke–induced brain damage,as well as the potential of these ncRNAs to act as biomarkers for acute ischemic stroke prediction,diagnosis,and prognosis.Findings from this review will provide novel ideas for the clinical application of ncRNAs in acute ischemic stroke.

Involvement of long non-coding RNAs in pear fruit senescence under high-and low-temperature conditions

Pear fruit senescence under high-and low-temperature conditions has been reported to be mediated by microRNAs.Long non-coding RNAs(lncRNAs),which can function as competing endogenous RNAs that interact with microRNAs,may also be involved in temperature-affected fruit senescence.Based on the transcriptome and microRNA sequencings,in this study,3330 lncRNAs were isolated from Pyrus pyrifolia fruit.Of these lncRNAs,2060 and 537 were responsive to high-and low-temperature conditions,respectively.Of these differentially expressed lncRNAs,82 and 24 correlated to the mRNAs involved in fruit senescence under high-and low-temperature conditions,respectively.Moreover,three lncRNAs were predicted to be competing endogenous RNAs(ceRNAs)that interact with the microRNAs involved in fruit senescence,while one and two ceRNAs were involved in fruit senescence under high-and low-temperature conditions,respectively.A dual-luciferase assay showed that the interaction of an lncRNA with a microRNA disrupts the action of the microRNA on the expression of its target mRNA(s).Furthermore,four alternative splicing-derived lncRNAs interacted with miR172i homologies(Novel_88 and Novel_69)to relieve the repressed expression of their target and produce an miR172i precursor.Correlation analysis of microRNA expression suggested that Novel_69 is likely involved in the cleavage of the pre-miR172i hairpin to generate mature miR172i.Taken together,lncRNAs are involved in pear fruit senescence under high-or low-temperature conditions through ceRNAs and the production of microRNA.

Expression profile of long non-coding RNAs in the intestine of black rockfish Sebastes schlegelii in response to Edwardsiella tarda infection

Long non-coding RNAs(lncRNAs)are a class of transcripts longer than 200 bp,which have been emerged as essential regulators in numerous biological processes.Black rockfish(Sebastes schlegelii)is an economic fish that widely cultured in the coastal areas of China,Japan,and South Korea.With the expansion of aquacultural scale,various pathogens have threatened its industry and reduced its economic values.It has been reported that lncRNA were involved in the immune response and metabolic pathway in teleost,while no study is available on identification and functional analysis of lncRNAs in black rockfish so far.Herein,this study was performed to identify lncRNAs in the intestine of black rockfish after Edwardsiella tarda infection.In our results,a total of 9311 lncRNAs were identified through highthroughput sequencing,and 102 lncRNAs were significantly regulated following challenge,which were predicted to target 3348 mRNAs.Results of Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses of the se target genes showed they were function in catalytic activity,hydrolase activity,defense response and peptidase activity,which involved in metabolic pathways and immune related pathways.In addition,47 lncRNAs and 8 differentially expressed mRNAs(DEmRNAs)showed co-expression at two or more infection time points with metabolism and immunity functions.Moreover,real-time quantitative PCR(qRT-PCR)was performed to verify the reliability of sequencing gene expression analysis results.This research laid the foundation for further investigation of the regulatory roles of lncRNAs in the intestinal immune response of black rockfish.

Identification and Characterization of Long Non-Coding RNAs Involved in Sex-Related Gene Regulation in Kelp Saccharina japonica

Long non-coding RNAs(lncRNAs)regulate a variety of biological processes,including sexual reproduction and differentiation.Saccharina japonica,a commercially important brown alga in China,shows remarkable sexual dimorphism in haploid gametophytes.The sex of Saccharina japonica gametophytes is determined by UV sexual system.However,no results have been reported on the lncRNAs involved in the sex-related gene regulation of S.japonica.This study identified a number of lncRNAs and assessed their expression levels in male and female gametophytes.Among them,a total of 405 lncRNAs and 211 mRNAs showed differential expressions.Furthermore,the functions of target genes of differentially expressed lncRNAs(DELs)differed from those of differentially expressed genes(DEGs),suggesting that lncRNA may interact with other functional proteins,in addition to DEGs,to involve sex regulation in S.japonica.There were 32 and 90 potential cis-regulatory and trans-regulatory interactions between DELsDEGs,respectively.Five of these lncRNAs(LNC_002974,LNC_021059,LNC_038466,LNC_051584,and LNC_027400)interacted with putative male sex determination region(SDR)genes,suggesting that they act as regulators in gametophytes'sex regulation potentially.Findings from this study contribute to our understanding of the roles of lncRNAs in sex differentiation and lay the foundation for functional studies of candidate lncRNAs in the future.

Bioinformatics Analysis and Experimental Verification of Prognostic and Biological Significance of Autophagy-Related Long Non-Coding RNAs in Gastric Carcinoma

Background:Long non-coding RNAs(lncRNAs)play a vital role in autophagy modulation and tumor progression.However,the key lncRNAs and their functions in gastric cancer(GC)remain largely unknown.Methods:A bioinformatic analysis of GC patients’gene expression profiling data from the Cancer Genome Atlas database was performed to identify autophagy-related lncRNAs that are associated with predictive risk.Through Cox regression and Lasso regression analyses,the autophagy-related lncRNAs that are associated with prognosis were identified,and a novel prognostic model for GC was established.The model was then used to evaluate the clinical features and predictive risk of individuals with GC.By using two datasets,GSE 62254(n=300)and GSE 15459(n=192),from Gene Expression Omnibus,its effectiveness was verified.Gene set enrichment analysis according to hallmark and Kyoto Encyclopedia of Genes and Genomes were used to determine the possible biological roles of these lncRNAs.Furthermore,the HOXD antisense growth-associated long non-coding RNA(HAGLR)mechanism in GC was discovered through in vitro and in vivo experiments.Results:Six lncRNAs associated with autophagy in GC were identified,and a new prognostic risk model based on these lncRNAs was established.The six-lncRNA signature was significantly associated with adverse clinicopathological features and found to be an independent GC prognostic factor.The model was proven to be effective and robust by GSE62254 and GSE15459.According to gene set enrichment analysis,the six lncRNAs appeared to be tightly linked to autophagy-related and cancer-related mechanisms.HAGLR was also found to promote tumor growth by enhancing autophagy signaling in GC.Conclusion:A novel prognostic model integrating HAGLR that can effectively evaluate and predict the prognostic risk of GC patients was established.The results indicated that HAGLR promotes gastric cancer progression by enhancing autophagy and is anticipated to be a potential new target for the treatment of gastric cancer.

The Dual Role of Non-coding RNAs in the Development of Periodontitis

This review aims to sum up how Non-coding RNAs(ncRNAs)regulate the development of periodontitis and provides a new perspective for understanding the pathogenesis of periodontitis.We explored the ncRNA's dual role in the development of periodontitis by summarizing evidence from previous in vivo and in vitro studies as well as clinical samples.In our review,the downregulation of 18 miRNAs,22 lncRNAs and 10 circRNAs demonstrates protective roles in periodontitis.In contrast,the expression of other 11 miRNAs,7 lncRNAs and 6 circRNAs are upregulated in periodontitis,which promote the progression of periodontitis.These dysregulated ncRNAs exert their protective or destructive roles by mainly influencing cell proliferation,differentiation and apoptosis via cross-talking with various molecules or signaling pathways.Our findings suggested which and how ncRNAs promote or delay the progression of periodontitis,which may greatly contribute to diagnose and therapy development of periodontitis based on ncRNAs in the future.

Non-coding RNAs:The potential biomarker or therapeutic target in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury(HIRI)is the major complication of liver surgery and liver transplantation,that may increase the postoperative morbidity,mortality,tumor progression,and metastasis.The underlying mechanisms have been extensively investigated in recent years.Among these,oxidative stress,inflammatory responses,immunoreactions,and cell death are the most studied.Non-coding RNAs(ncRNAs)are defined as the RNAs that do not encode proteins,but can regulate gene expressions.In recent years,ncRNAs have emerged as research hotspots for various diseases.During the progression of HIRI,ncRNAs are differentially expressed,while these dysregulations of ncRNAs,in turn,have been verified to be related to the above pathological processes involved in HIRI.ncRNAs mainly contain microRNAs,long ncRNAs,and circular RNAs,some of which have been reported as biomarkers for early diagnosis or assessment of liver damage severity,and as therapeutic targets to attenuate HIRI.Here,we briefly summarize the common pathophysiology of HIRI,describe the current knowledge of ncRNAs involved in HIRI in animal and human studies,and discuss the potential of ncRNA-targeted therapeutic strategies.Given the scarcity of clinical trials,there is still a long way to go from pre-clinical to clinical application,and further studies are needed to uncover their potential as therapeutic targets.

Analysis of long non-coding RNA expression profiles in gastric cancer

AIM: To investigate the expression patterns of long non-coding RNAs (lncRNAs) in gastric cancer. METHODS: Two publicly available human exon arrays for gastric cancer and data for the corresponding normal tissue were downloaded from the Gene Expression Omnibus (GEO). We re-annotated the probes of the human exon arrays and retained the probes uniquely mapping to lncRNAs at the gene level. LncRNA expression profiles were generated by using robust multi-array average method in affymetrix power tools. The normalized data were then analyzed with a Bioconductor package linear models for microarray data and genes with adjusted P -values below 0.01 were considered differentially expressed. An independent data set was used to validate the results. RESULTS: With the computational pipeline established to re-annotate over 6.5 million probes of the Affymetrix Human Exon 1.0 ST array, we identified 136053 probes uniquely mapping to lncRNAs at the gene level. These probes correspond to 9294 lncRNAs, covering nearly 76% of the GENCODE lncRNA data set. By analyzing GSE27342 consisting of 80 paired gastric cancer and normal adjacent tissue samples, we identified 88 lncRNAs that were differentially expressed in gastric cancer, some of which have been reported to play a role in cancer, such as LINC00152, taurine upregulated 1, urothelial cancer associated 1, Pvt1 oncogene, small nucleolar RNA host gene 1 and LINC00261. In the validation data set GSE33335, 59% of these differentially expressed lncRNAs showed significant expression changes (adjusted P -value < 0.01) with the same direction. CONCLUSION: We identified a set of lncRNAs differentially expressed in gastric cancer, providing useful information for discovery of new biomarkers and therapeutic targets in gastric cancer.

Diagnostic and prognostic potential of tissue and circulating long non-coding RNAs in colorectal tumors

Long non-coding RNAs(lncRNAs)are members of the non-protein coding RNA family longer than 200 nucleotides.They participate in the regulation of gene and protein expression influencing apoptosis,cell proliferation and immune responses,thereby playing a critical role in the development and progression of various cancers,including colorectal cancer(CRC).As CRC is one of the most frequently diagnosed malignancies worldwide with high mortality,its screening and early detection are crucial,so the identification of disease-specific biomarkers is necessary.LncRNAs are promising candidates as they are involved in carcinogenesis,and certain lncRNAs(e.g.,CCAT1,CRNDE,CRCAL1-4)show altered expression in adenomas,making them potential early diagnostic markers.In addition to being useful as tissue-specific markers,analysis of circulating lncRNAs(e.g.,CCAT1,CCAT2,BLACAT1,CRNDE,NEAT1,UCA1)in peripheral blood offers the possibility to establish minimally invasive,liquid biopsy-based diagnostic tests.This review article aims to describe the origin,structure,and functions of lncRNAs and to discuss their contribution to CRC development.Moreover,our purpose is to summarise lncRNAs showing altered expression levels during tumor formation in both colon tissue and plasma/serum samples and to demonstrate their clinical implications as diagnostic or prognostic biomarkers for CRC.

Circulating micro RNAs and long non-coding RNAs in gastric cancer diagnosis:An update and review

Gastric cancer(GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. Micro RNAs(mi RNAs) and long non-coding RNAs(lnc RNAs) are the most popular non-coding RNAs in cancer research. To date,the roles of mi RNAs and lnc RNAs have been extensively studied in GC,suggesting that mi RNAs and lnc RNAs represent a vital component of tumor biology. Furthermore,circulating mi RNAs and lnc RNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating mi RNAs and lnc RNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for mi RNA secretion have been elucidated,including active secretion by microvesicles,exosomes,apoptotic bodies,highdensity lipoproteins and protein complexes as well as passive leakage from cells. However,the mechanism underlying lnc RNA secretion and the functions of circulating mi RNAs and lnc RNAs have not been fully illuminated. Concurrently,to standardize results of global investigations of circulating mi RNAs and lnc RNAs biomarker studies,several recommendations for preanalytic considerations are put forward. In this review,we summarize the known circulating mi RNAs and lnc RNAs for GC diagnosis. The possible mechanism of mi RNA and lnc RNA secretion as well as methodologies for identification of circulating mi RNAs and lnc RNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

Functional role of long non-coding RNA CASC19/miR-140-5p/CEMIP axis in colorectal cancer progression in vitro

BACKGROUND Long non-coding RNAs(lncRNAs) are widely involved in tumor regulation.Nevertheless, the role of the lncRNA cancer susceptibility 19(CASC19) in colorectal cancer(CRC) has yet to be fully clarified.AIM To explore the effect of CASC19 on proliferation and metastasizing ability of CRC cells.METHODS CASC19 expression in human CRC tissues, pair-matched adjacent normal colon tissues, and CRC cells was detected using quantitative real-time PCR(qRT-PCR).CASC19 expression, as well as its relation to overall survival, was extrapolated by Kaplan-Meier survival analysis together with multivariable Cox regression assay.In vitro experiments were performed to confirm whether CASC19 regulates CRC cell invasion, migration, proliferation, and apoptosis.RESULTS CASC19 expression was markedly upregulated in CRC tissues and CRC cell lines(P < 0.05). qRT-PCR revealed that CASC19 expression was higher in 25 tissue samples from patients with aggressive CRC compared with the 27 tissue samples from patients with nonaggressive CRC(P < 0.05). Higher CASC19 expression was associated with poorer patient prognoses. Furthermore, in vitro experiments demonstrated that CASC19 overexpression enhanced CRC cell invasion,migration, and proliferation. CASC19 overexpression enhanced the expression of cell migration inducing hyaluronidase 1(CEMIP) and epithelial-mesenchymal transition markers. MiR-140-5 p was found to be able to bind directly to CASC19 and CEMIP. Overexpression of miR-140-5 p reversed the effect of CASC19 on cellproliferation and tumor migration, as well as suppressed CASC19-induced CEMIP expression.CONCLUSION CASC19 positively regulates CEMIP expression through targeting miR-140-5 p.CASC19 may possess an oncogenic function in CRC progression, highlighting its potential as an essential biomarker in CRC diagnosis and therapy.

Value of long non-coding RNA Rpph1 in esophageal cancer and its effect on cancer cell sensitivity to radiotherapy

BACKGROUND Esophageal cancer is a common digestive tract tumor that is generally treated with radiotherapy.Poor responses to radiotherapy in most patients generally result in local radiotherapy failure,so it is essential to find new radiosensitizers that can enhance the response of cancer cells to radiotherapy and improve the survival of esophageal cancer patients with radiation resistance.The long noncoding RNA(lncRNA)Rpph1 is highly expressed in human gastric cancer tissues,and represses breast cancer cell proliferation and tumorigenesis.However,the expression of lncRNA Rpph1 in esophageal cancer and its relationship with radio-sensitivity has not been studied.AIM To explore the value of lncRNA Rpph1 in esophageal cancer and its effect on cancer cell sensitivity to radiotherapy.METHODS Eighty-three patients with esophageal cancer admitted to Qilu Hospital of Shandong University and 90 healthy participants who received physical examinations were collected as research participants.The expression of Rpph1 was determined by qRT-PCR.siRNA-NC and siRNA-Rpph1 were transfected into esophageal cancer cell lines,and cells without transfection were designated as the blank control group.Cell survival was tested by colony formation assays,and the levels of proteins related to apoptosis and epithelial-mesenchymal transitions were determined by Western blot assays.Cell proliferation was assessed by MTT assays,cell apoptosis by flow cytometry,and cell migration by wound-healing assays.Changes in cell cycle distribution were monitored.RESULTS Rpph1 was highly expressed in esophageal carcinoma,making it a promising marker for the diagnosis of esophageal cancer.Rpph1 could also be used to distinguish different short-term responses,T stages,N stages,and clinical stages of esophageal cancer patients.The results of 3-year overall survival favored patients with lower Rpph1 expression over patients with higher Rpph1 expression(P<0.05).In vitro and in vivo experiments showed that silencing Rpph1 expression led to higher sensitivity of esophageal cancer cells to radiotherapy,stronger apoptosis in esophageal cancer cells induced by radiotherapy,higher expression of Bax and caspase-3,and lower expression of Bcl-2(Bax,caspase-3,and Bcl-2 are apoptosis-related proteins).Additionally,silencing Rpph1 attenuated radiation-induced G2/M phase arrest,and significantly inhibited the expression of proteins involved in cell proliferation,migration,and epithelial-mesenchymal transition regulation in esophageal cancer cells.CONCLUSION Rpph1 is highly expressed in esophageal cancer.Silencing Rpph1 expression can promote cell apoptosis,inhibit cell proliferation and migration,and increase radio-sensitivity.

Behind the curtain of non-coding RNAs; long non-coding RNAs regulating hepatocarcinogenesis

Hepatocellular carcinoma(HCC) is one of the most common and aggressive cancers worldwide. HCC is the fifth common malignancy in the world and the second leading cause of cancer death in Asia. Long non-coding RNAs(lncRNAs) are RNAs with a length greater than 200 nucleotides that do not encode proteins. lncRNAs can regulate gene expression and protein synthesis in several ways by interacting with DNA, RNA and proteins in a sequence specific manner. They could regulate cellular and developmental processes through either gene inhibition or gene activation. Many studies have shown that dysregulation of lncRNAs is related to many human diseases such as cardiovascular diseases, genetic disorders, neurological diseases, immune mediated disorders and cancers. However, the study of lncRNAs is challenging as they are poorly conserved between species, their expression levels aren't as high as that of m RNAs and have great interpatient variations. The study of lncRNAs expression in cancers have been a breakthrough as it unveils potential biomarkers and drug targets for cancer therapy and helps understand the mechanism of pathogenesis. This review discusses many long non-coding RNAs and their contribution in HCC, their role in development, metastasis, and prognosis of HCC and how to regulate and target these lncRNAs as a therapeutic tool in HCC treatment in the future.

Six-long non-coding RNA signature predicts recurrence-free survival in hepatocellular carcinoma

BACKGROUND Recent evidence shows that long non-coding RNAs(lncRNAs) are closely related to hepatogenesis and a few aggressive features of hepatocellular carcinoma(HCC). Increasing studies demonstrate that lncRNAs are potential prognostic factors for HCC. Moreover, several studies reported the combination of lncRNAs for predicting the overall survival(OS) of HCC, but the results varied. Thus,more effort including more accurate statistical approaches is needed for exploring the prognostic value of lncRNAs in HCC.AIM To develop a robust lncRNA signature associated with HCC recurrence to improve prognosis prediction of HCC.METHODS Univariate COX regression analysis was performed to screen the lncRNAs significantly associated with recurrence-free survival(RFS) of HCC in GSE76427 for the least absolute shrinkage and selection operator(LASSO) modelling. The established lncRNA signature was validated and developed in The Cancer Genome Atlas(TCGA) series using Kaplan-Meier curves. The expression values of the identified lncRNAs were compared between the tumor and non-tumor tissues. Pathway enrichment of these lncRNAs was conducted based on the significantly co-expressed genes. A prognostic nomogram combining the lncRNA signature and clinical characteristics was constructed.RESULTS The lncRNA signature consisted of six lncRNAs: MSC-AS1, POLR2 J4, EIF3 J-AS1,SERHL, RMST, and PVT1. This risk model was significantly associated with the RFS of HCC in the TCGA cohort with a hazard ratio(HR) being 1.807(95%CI[confidence interval]: 1.329-2.457) and log-rank P-value being less than 0.001. The best candidates of the six-lncRNA signature were younger male patients with HBV infection in relatively early tumor-stage and better physical condition but with higher preoperative alpha-fetoprotein. All the lncRNAs were significantly upregulated in tumor samples compared to non-tumor samples(P < 0.05). The most significantly enriched pathways of the lncRNAs were TGF-β signaling pathway, cellular apoptosis-associated pathways, etc. The nomogram showed great utility of the lncRNA signature in HCC recurrence risk stratification.CONCLUSION We have constructed a six-lncRNA signature for prognosis prediction of HCC.This risk model provides new clinical evidence for the accurate diagnosis and targeted treatment of HCC.

Long Non-coding RNA MEG3 Induces Renal Cell Carcinoma Cells Apoptosis by Activating the Mitochondrial Pathway

Summary： This study aimed to examine the effect of long non-coding RNA （LncRNA） MEG3 on the biological behaviors of renal cell carcinoma （RCC） cells 786-0 and the possible mechanism. MEG3 expression levels were detected by RT-qPCR in Rmaor tissues and adjacent non-tumor tissues from 29 RCC patients and in RCC lines 786-0 and SN12 and human embryonic kidney cell line 293T. Plasmids GV144-MEG3 （MEG3 overexpression plasmid） and GV144 （control plasmid） were stably transfected into 786-0 cells by using lipofectamine 2000. Cell viabilities were determined by MTT, cell apoptosis rates by flow cytometry following PE Annexin V and 7AAD staining, apoptosis-related protein expressions by Western blotting, and Bcl-2 mRNA by RT-qPCR in the transfected cells. The results showed that MEG3 was evidently downregulated in RCC tissues （P〈0.05） and RCC cell lines （P〈0.05）. The viabilities of 786-0 cells were decreased significantly after transfection with GV144-MEG3 for over 24 h （P〈0.05）. Consistently, the apoptosis rate was significantly increased in 786-0 cells transfected with GV144-MEG3 for 48 h （P〈0.05）. Furthermore, overexpression of MEG3 could reduce the expression of Bcl-2 and procaspase-9 proteins, enhance the expression of cleaved caspase-9 protein, and promote the release of cytochrome c protein to cytoplasm （P〈0.05）. Additionally, Bcl-2 mRNA level was declined by MEG3 overexpression （P〈0.05）. It was concluded that MEG3 induces the apoptosis of RCC cells possibly by activating the mitochondrial pathway.

Identification of a five-long non-coding RNA signature to improve the prognosis prediction for patients with hepatocellular carcinoma

AIM To construct a long non-coding RNA(lnc RNA) signature for predicting hepatocellular carcinoma(HCC) prognosis with high efficiency.METHODS Differentially expressed lnc RNAs(DELs) between HCC specimens and peritumor liver specimens were identified using the edge R package to analyze The Cancer Genome Atlas(TCGA) LIHC dataset.Univariate Cox proportional hazards regression was performed to obtain the DELs significantly associated with overall survival(OS) in a training set.These OS-related DELs were further analyzed using a stepwise multivariate Cox regression model.Those lnc RNAs fitted in the multivariate Cox regression model and independently associated with overall survival were chosen to build a prognostic risk formula.The prognostic value ofthis formula was then validated in the test group and the entire cohort and further compared with two previously identified prognostic signatures for HCC.Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to explore the potential biological functions of the lnc RNAs in the signature.RESULTS Based on lnc RNA expression profiling of 370 HCC patients from the TCGA database,we constructed a 5-lnc RNA signature(AC015908.3,AC091057.3,TMCC1-AS1,DCST1-AS1 and FOXD2-AS1) that was significantly associated with prognosis.HCC patients with high-risk scores based on the expression of the 5 lnc RNAs had significantly shorter survival times compared to patients with low-risk scores in both the training and test groups.Multivariate Cox regression analysis demonstrated that the prognostic value of the 5 lnc RNAs was independent of clinicopathological parameters.A comparison study involving two previously identified prognostic signatures for HCC demonstrated that this 5-lnc RNA signature showed improved prognostic power compared with the other two signatures.Functional enrichment analysis indicated that the 5 lnc RNAs were potentially involved in metabolic processes,fibrinolysis and complement activation.CONCLUSION Our present study constructed a 5-lnc RNA signature that improves survival prediction and can be used as a prognostic biomarker for HCC patients.

Long non-coding RNA highly up-regulated in liver cancer promotes exosome secretion

BACKGROUND Highly upregulated in liver cancer (HULC) is a long non-coding RNA (lncRNA) which has recently been identified as a key regulator in hepatocellular carcinoma (HCC) progression. However, its role in the secretion of exosomes from HCC cells remains unknown. AIM To explore the mechanism by which HULC promotes the secretion of exosomes from HCC cells. METHODS Serum and liver tissue samples were collected from 30 patients with HCC who had not received chemotherapy, radiotherapy, or immunotherapy before surgery. HULC expression in serum exosomes and liver cancer tissues of patients was measured, and compared with the data obtained from healthy controls and tumor adjacent tissues. The effect of HULC upregulation in HCC cell lines and the relationship between HULC and other RNAs were studied using qPCR and dualluciferase reporter assays. Nanoparticle tracking analysis was performed to detect the quantity of exosomes.RESULTS HULC expression in serum exosomes of patients with HCC was higher than that in serum exosomes of healthy controls, and HULC levels were higher in liver cancer tissues than in tumor adjacent tissues. The expression of HULC in serum exosomes and liver cancer tissues correlated with the tumor-node-metastasis (TNM) classification, and HULC expression in tissues correlated with that in serum exosomes. Upregulation of HULC promoted HCC cell growth and invasion and repressed apoptosis. Notably, it also facilitated the secretion of exosomes from HCC cells. Moreover, qPCR assays showed that HULC repressed microRNA-372-3p (miR-372-3p) expression. We also identified Rab11a as a downstream target of miR-372-3p. Dual-luciferase reporter assays suggested that miR-372-3p could directly bind both HULC and Rab11a. CONCLUSION Our findings illustrate the importance of the HULC/miR-372-3p/Rab11a axis in HCC and provide new insights into the molecular mechanism regulating the secretion of exosomes from HCC cells.

Emerging role of long non-coding RNA in the development of gastric cancer

Gastric cancer is a common, worldwide malignancy and has a poor prognosis due to late diagnosis. Long non-coding RNAs(lnc RNAs) are a significant subtype of RNA molecules with a length longer than 200 nucleotides(nt) that rarely encode proteins. In recent decades, deregulation of lnc RNAs has been shown to be involved in tumorigenesis and tumor progression in various human carcinomas, including gastric cancer. Accumulating evidence has shown that some lnc RNAs may function as diagnostic biomarkers or therapeutic targets for gastric cancer. Thus, exploring the specific functions of lnc RNAs will help both gain a better understanding of the pathogenesis and develop novel treatments for gastric cancer. In this review, we highlight the expression and functional roles of lncR NAs in gastric cancer, and analyze the potential applications of lncR NAs as diagnostic markers and therapeutic targets.

Long non-coding RNAs in stem cells and cancer

An overwhelming majority of the transcribed genome encodes for non-coding RNA(ncR NA) sequences. Deep sequencing of the transcriptome has uncovered tens of thousands of long ncR NA(lncR NA) sequences. However, little is known regarding the possible functions for a vast majority of these sequences. Among those lncR NAs whose function has been experimentally validated, most serve as regulators of gene expression. LncR NAs have been found to be critical to development and homeostasis and they have been implicated in several pathologies including cancer. Here, we examine the functions and underlying mechanisms of lnc RNAs in stem cells and in cancer biology, areas linked by the actions of lncR NAs.