HOTAIR:an oncogenic long non-coding RNA in different cancers

Long non-coding RNAs(lncRNAs) refer to a group of RNAs that are usually more than 200 nucleotides and are not involved in protein generation. Instead, lncRNAs are involved in different regulatory processes, such as regulation of gene expression. Different lncRNAs exist throughout the genome. Lnc RNAs are also known for their roles in different human diseases such as cancer. HOTAIR is an lnc RNA that plays a role as an oncogenic molecule in different cancer cells, such as breast, gastric, colorectal, and cervical cancer cells. Therefore, HOTAIR expression level is a potential biomarker for diagnostic and therapeutic purposes in several cancers. This RNA takes part in epigenetic regulation of genes and plays an important role in different cellular pathways by interacting with Polycomb Repressive Complex 2(PRC2). In this review, we describe the molecular function and regulation of HOTAIR and its role in different types of cancers.

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.

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.

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.

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.

Knockdown of long non-coding RNA LCPAT1 inhibits autophagy in lung cancer

Objective: Long non-coding RNAs(lnc RNAs) are involved in numerous biological processes in lung cancer cells. In our previous studies, we identified a lnc RNA, ENST00000439577, which is highly expressed in lung carcinomas, and termed it lung cancer progression-associated transcript 1(LCPAT1). To characterize the role of LCPAT1 in lung cancer, we conducted the current study.Methods: Expression of LCPAT1 and autophagy-associated markers in tumor tissues and lung cancer cell lines was determined by real-time quantitative polymerase chain reaction(q PCR). Hematoxylin and eosin(HE) staining, q PCR, Western blot, and immunohistochemistry were performed to evaluate xenografted tumor tissues. Autophagy induced by rapamycin was detected by Western blot and immunofluorescence in lung cancer cell lines.Results: Expression of LCPAT1 and microtubule-associated protein 1 light chain 3 beta(LC3B) was positively correlated in lung cancer. Knockdown of LCPAT1 inhibited tumor growth and suppressed cell autophagy in vivo. Moreover, LCPAT1 knockdown in lung cancer cell lines resulted in decreased autophagy-associated gene expression and alleviated the cell autophagy induced by rapamycin.Conclusions: We speculate that LCPAT1 plays a crucial role in regulating autophagy in lung cancer.

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.

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.

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.

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.

Expression Profile of Altered Long Non-coding RNAs in Patients with HBV-associated Hepatocellular Carcinoma

In China, hepatitis B virus （HBV） infection is the major cause of hepatocellular carcinoma （HCC）, which is called HBV-related HCC （HBV-HCC）, but the pathogenesis has not been clearly elu- cidated. Long non-coding RNAs （lncRNAs） have been paid increasing attention to, as an important regulatory molecule involved in many biological processes, as well as a variety of diseases. This study examined lncRNA that might play an important role in HBV-HCC pathogenesis by conducting lncRNA and mRNA profile comparison between HBV-HCC and normal liver tissues. The differentially ex- pressed lncRNA and mRNA profiles between HBV-HCC and normal liver tissues were analyzed by mi- croarrays. The potential protein-encoding gene regulated by lncRNA, and the biological function （gene ontology, pathway analysis） of the target gene were investigated. The results showed that the expression levels of lncRNA and mRNA in HBV-HCC tissues were different from those in normal liver tissues. As compared with normal liver tissue, 837 （4.30%） lncRNAs exhibited more than two-fold change （P〈0.05）; 325 were up-regulated, and 512 were down-regulated; 991 （5.70%） mRNAs exhibited more than 2-fold change （P〈0.05）; 733 were up-regulated and 258 were down-regulated in HBV-HCC tissue. Besides, there were 7 lncRNAs with above 10-fold elevation, 6 lncRNAs with above 10-fold decrease, 18 mRNAs with above 10-fold elevation and 11 mRNAs with above 10-fold decrease. 444 （53.05%） lncRNAs had their corresponding mRNAs, some of which were adjacent to lncRNAs. The biological analysis showed that the target gene of differentially expressed lncRNAs took part in the important bio- logical regulatory function. Target gene-related pathway analysis revealed the pathways in carcinoma and mitogen-activated protein kinase （MAPK） signaling pathways significantly changed in the HBV-HCC tissues as compared with normal liver tissues （P〈0.05）. It was suggested that as compared with normal liver tissues, the expression of lncRNAs in HBV-HCC tissues changed significantly, and lncRNAs played a key role in the pathogenesis of HBV-HCC probably by mainly regulating the carci- noma-related signaling pathway and MAPK signaling pathways.

Long non-coding RNA HULC as a diagnostic and prognostic marker of pancreatic cancer

BACKGROUND Long non-coding RNA(lncRNA)is abnormally expressed in various malignant tumors.In recent years,it has been found that IncRNA HULC is increasingly expressed in pancreatic cancer tissues and is involved in the development and progression of pancreatic cancer.However,the clinical value of serum HULC in pancreatic cancer remains unclear,and there are few studies on how HULC regulates the biological function of pancreatic cancer cells.AIM To determine the value of lncRNA HULC in the diagnosis and prognosis of pancreatic cancer,and its possible biological potential.METHODS Sixty patients with pancreatic cancer and sixty patients with benign pancreatic diseases admitted to Xiangya Hospital,Central South University were assigned to the pancreatic cancer group and the benign disease group,respectively,and another 60 healthy subjects were enrolled as the normal group during the same period.HULC-siRNA and NC-siRNA were transfected into pancreatic cancer cells.Quantitative real-time polymerase chain reaction was performed to determine the expression of HULC in tissues,serum,and cells.Western Blot was carried out to determine the expression ofβ-catenin,c-myc,and cyclin D1 in cells,and the cell counting kit-8,flow cytometry,and Transwell assay were conducted to determine the proliferation,apoptosis and invasion of cells.RESULTS Highly expressed in the tissues and serum of pancreatic cancer patients,HULC showed good clinical value in distinguishing between patients with pancreatic cancer,patients with benign pancreatic diseases and healthy subjects.HULC was related to pathological parameters including tumor size,T staging,M staging and vascular invasion,and the area-under-the-curve for evaluating these four expression of HULC had a significantly higher 3-year overall survival(OS)and 5-year OS than those with high expression.T staging,M staging,vascular invasion,and HULC were independent prognostic factors affecting the 3-year OS of patients with pancreatic cancer.Inhibition of HULC expression prevented the proliferation and invasion of pancreatic cancer cells,promoted apoptosis,and inhibited the expression of Wnt/β-catenin signaling pathway-related proteins,β-catenin,c-myc,and cyclin D1.The Wnt/β-catenin signaling pathway agonist(LiCl)restored proliferation,apoptosis,and invasion of pancreatic cancer cells with inhibited expression of HULC.CONCLUSION HULC is an effective marker for the diagnosis and prognosis of pancreatic cancer,which may affect the biological function of pancreatic cancer cells through the Wnt/β-catenin signaling pathway.

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 RNAs era in liver cancer

Hepatocellular carcinoma(HCC) is one of the most common malignancies leading to high mortality rates in the general population and the sixth most common cancer worldwide. HCC is characterized by deregulation of multiple genes and signalling pathways. These genetic effects can involve both protein coding genes as well as non-coding RNA genes. Long noncoding RNAs(lnc RNAs) are transcripts longer than 200 nt, constituting a subpopulation of nc RNAs. Their biological effects are not well understood comparedto small non-coding RNA(micro RNAs), but they have been recently recognized to exert a crucial role in the regulation of gene expression and modulation of signalling pathways. Notably, several studies indicated that lnc RNAs contribute to the pathogenesis and progression of HCC. Investigating the molecular mechanisms underlying lnc RNAs expression opens potential applications in diagnosis and treatment of liver disease. This editorial provides three examples(MALAT-1 metastasis associated lung adenocarcinoma transcript, HULC highly upregulated in liver cancer and HOTAIR HOX transcript antisense intergenic RNA) of well-known lnc RNAs upregulated in HCC, whose mechanisms of action are known, and for which therapeutic applications are delineated. Targeting of lnc RNAs using several approaches(siR NA-mediated silencing or changing their secondary structure) offers new possibility to treat HCC.

Regulatory role of long non coding RNAs (lncRNAs) in neurological disorders:From novel biomarkers to promising therapeutic strategies

Long non coding RNAs(lncRNAs) are non-protein or low-protein coding transcripts that contain more than 200 nucleotides. They representing a large share of the cell’s transcriptional output, demonstrate functional attributes viz. tissue-specific expression, determination of cell fate, controlled expression, RNA processing and editing, dosage compensation, genomic imprinting, conserved evolutionary traits etc. These long non coding variants are well associated with pathogenicity of various diseases including the neurological disorders like Alzheimer’s disease, schizophrenia, Huntington’s disease, Parkinson’s disease etc. Neurological disorders are widespread and there knowing the underlying mechanisms become crucial. The lncRNAs take part in the pathogenesis by a plethora of mechanisms like decoy, scaffold, mi-RNA sequestrator, histone modifiers and in transcriptional interference. Detailed knowledge of the role of lncRNAs can help to use them further as novel biomarkers for therapeutic aspects. Here, in this review we discuss regulation and functional roles of lncRNAs in eight neurological diseases and psychiatric disorders, and the mechanisms by which they act. With these, we try to establish their roles as potential markers and viable diagnostic tools in these disorders.

Roles of long non-coding RNAs in gastric cancer metastasis

Gastric cancer is the second leading cause of cancer-related deaths.Metastasis,which is an important element of gastric cancer,leads to a high mortality rate and to a poor prognosis.Gastric cancer metastasis has a complex progression that involves multiple biological processes.The comprehensive mechanisms of metastasis remain unclear,though traditional regulation modulates the molecular functions associated with metastasis.Long non-coding RNAs(lnc RNAs) have a role in different gene regulatory pathways by epigenetic modification and by transcriptional and post-transcription regulation.lnc RNAs participate in various diseases,including Alzheimer's disease,cardiovascular disease,and cancer.The altered expressions of certain lnc RNAs are linked to gastric cancer metastasis and invasion,as with tumor suppressor genes or oncogenes.Studies have partly elucidated the roles of lnc RNAs as biomarkers and in therapies,as well as their gene regulatory mechanisms.However,comprehensive knowledge regarding the functional mechanisms of gene regulation in metastatic gastric cancer remains scarce.To provide a theoretical basis for therapeutic intervention in metastatic gastric cancer,we reviewed the functions of lnc RNAs and their regulatory roles in gastric cancer metastasis.

Targeting long non-coding RNA MALAT1 alleviates retinal neurodegeneration in diabetic mice

●AIM:To observe the effect of inhibiting long non-coding RNA(lncRNA)metastasis-associated lung adenocarcinoma transcript 1(MALAT1)on diabetic neurodegeneration.●METHODS:Thirty-six 8-week-old C57 BL/6 mice were randomly divided into normal control,diabetic control,diabetic scrambled small interfering RNAs(siRNAs)and diabetic MALAT1-siRNA groups.After diabetic induction with streptozocin intraperitoneally-injection,the diabetic M A L AT 1-s i R N A g ro u p w a s i n t r av i t r e a l l y i n j e c te d with 1μL 20μmol/L MALAT1 siRNA,and the diabetic scrambled siRNA group was injected with the same amount of scrambled siRNA.Electroretinography was performed to examine photoreceptor functions 16 wk after diabetes induction.MALAT1 expression was detected via real time polymerase chain reaction.Cone morphological changes were examined using immunofluorescence.Rod morphological changes were examined by determining outer nuclear layer(ONL)thickness.●RESULTS:The upregulation of retinal MALAT1 expression was detected in the diabetic control mice,while MALAT1 expression in the diabetic MALAT1-siRNA mice was decreased by 91.48%compared to diabetic control mice.The diabetic MALAT1-siRNA and diabetic control mice showed lower a-wave and b-wave amplitudes than did the normal control mice in scotopic and photopic electroretinogram,while the diabetic MALAT1-siRNA mice showed higher amplitudes than diabetic control mice.Morphological examination revealed that ONL thickness in the diabetic MALAT1-siRNA and diabetic control mice was lower than normal control mice.However,ONL thickness was greater in the diabetic MALAT1-siRNA mice than diabetic control mice.Moreover,the diabetic control mice performed a sparser cone cell arrangement and shorter outer segment morphology than diabetic MALAT1-siRNA mice.●CONCLUSION:Inhibiting retinal MALAT1 results in mitigative effects on the retinal photoreceptors,thus alleviating diabetic neurodegeneration.

Long non-coding RNA: The functional regulator of mesenchymal stem cells

Mesenchymal stem cells(MSCs) are a subset of multipotent stroma cells residing in various tissues of the body. Apart from supporting the hematopoietic stem cell niche, MSCs possess strong immunoregulatory ability and multiple differentiation potentials. These powerful capacities allow the extensive application of MSCs in clinical practice as an effective treatment for diseases.Therefore, illuminating the functional mechanism of MSCs will help to improve their curative effect and promote their clinical use. Long noncoding RNA(LncRNA) is a novel class of noncoding RNA longer than 200 nt. Recently,multiple studies have demonstrated that LncRNA is widely involved in growth and development through controlling the fate of cells, including MSCs. In this review, we highlight the role of LncRNA in regulating the functions of MSCs and discuss their participation in the pathogenesis of diseases and clinical use in diagnosis and treatment.