Up-regulation of LncRNA SNHG20 Predicts Poor Prognosis in Hepatocellular Carcinoma

High expression of small nucleolar host gene RNA may predict poor prognosis of Hepatocellular carcinoma, based on systematic reviews and meta-analyses

BACKGROUND

The prognosis of patients with hepatocellular cancer is substantially correlated with the abnormal expression of growing long non-coding RNA small nucleolar host gene RNA (SNHG) families in liver cancer tissues. This study aimed to examine the relationship between SNHG expression and liver cancer prognosis.

METHODS

After searching six internet databases, pertinent manuscripts were found based on inclusion and exclusion criteria. To determine whether SNHG expression levels affect liver cancer prognosis, raw data were collected and hazard ratios (HRs) and odds ratios (ORs) were calculated. The results were examined for potential publication bias using the sensitivity analysis and Beeg's test.

RESULTS

Most SNHG family members were up-regulated in liver cancer tissues. High SNHG expression predicts poor liver cancer outcomes of, including overall survival (OS) (HR: 1.697, 95% confidence interval [CI]: 1.373-2.021), especially SNHG5 (the HR of OS is 4.74, 95%CI range from 1.35 to 6.64), progression-free survival (HR: 1.85, 95% CI: 1.25-2.73), tumor, node, metastasis (TNM) stage (OR: 1.696, 95% CI: 1.436-2.005), lymph node metastasis (OR: 2.383, 95% CI: 1.098-5.173), and tumor size (OR: 1363, 95% CI: 1.165-1.595). The OS results were found to be reliable and robust, as indicated by the sensitivity analysis. Additionally, Beeg's test demonstrated the absence of any potential publication bias for each result.

CONCLUSION

In liver cancer tissues, most SNHGs are highly expressed, which may signal poor prognosis. SNHG has the potential to be an intriguing predictive marker and a prospective therapeutic target for liver cancer.

Functional role of lncRNAs in gastrointestinal malignancies: the peculiar case of small nucleolar RNA host gene family

Long noncoding RNAs (lncRNAs) play crucial roles in normal physiology and are often de-regulated in disease states such as cancer. Recently, a class of lncRNAs referred to as the small nucleolar RNA host gene (SNHG) family have emerged as important players in tumourigenesis. Here, we discuss new findings describing the role of SNHGs in gastrointestinal tumours and summarize the three main functions by which these lncRNAs promote carcinogenesis, namely: competing with endogenous RNAs, modulating protein function, and regulating epigenetic marking. Furthermore, we discuss how SNHGs participate in different hallmarks of cancer, and how this class of lncRNAs may serve as potential biomarkers in cancer diagnosis and therapy.

Long noncoding RNA small nucleolar RNA host genes as prognostic molecular biomarkers in hepatocellular carcinoma: A meta-analysis

BACKGROUND

Recently, increasing data have suggested that the lncRNA small nucleolar RNA host genes (SNHGs) were aberrantly expressed in hepatocellular carcinoma (HCC), but the association between the prognosis of HCC and their expression remained unclear. The purpose of this meta-analysis was to determine the prognostic significance of lncRNA SNHGs in HCC.

METHODS

We systematically searched Embase, Web of Science, PubMed, and Cochrane Library for eligible articles published up to February 2024. The prognostic significance of SNHGs in HCC was evaluated by hazard ratios (HRs) and 95% confidence intervals (CIs). Odds ratios (ORs) were used to assess the clinicopathological features of SNHGs.

RESULTS

This analysis comprised a total of 25 studies covering 2314 patients with HCC. The findings demonstrated that over-expressed SNHGs were associated with larger tumor size, multiple tumor numbers, poor histologic grade, earlier lymphatic metastasis, vein invasion, advanced tumor stage, portal vein tumor thrombosis (PVTT), and higher alpha-fetoprotein (AFP) level, but not with hepatitis B virus (HBV) infection, and cirrhosis. In terms of prognosis, patients with higher SNHG expression were more likely to have shorter overall survival (OS), relapse-free survival (RFS), and disease-free survival (DFS).

CONCLUSIONS

In conclusion, upregulation of SNHGs expression correlates with shorter OS, RFS, DFS, tumor size and numbers, histologic grade, lymphatic metastasis, vein invasion, tumor stage, PVTT, and AFP level, suggesting that SNHGs may serve as prognostic biomarkers in HCC.

Knockdown of lncRNA SNHG20 Suppressed the Proliferation of Cholangiocarcinoma by Sponging miR-520f-3p

Objective: A large number of studies had found that small nucleolar RNA host gene 20 (SNHG20) was a long noncoding RNA (lncRNA) that played important regulatory functions in numerous tumors. Nevertheless, the expression and pathophysiological role of SNHG20 in cholangiocarcinoma (CCA) are currently unclear. The objective of this study is to reveal the clinical significance and pathophysiological function of SNHG20 in CCA. Methods: The tumor tissues and adjacent normal tissues of CCA were obtained to determine the expression and clinical significance of SNHG20, and the targets of related genes were predicted through bioinformatics analysis. The function and regulatory mechanism of SNHG20 in CCA were evaluated by transfection, CCK-8 experiment, and luciferase reporter assay. Result: In CCA, SNHG20 was highly expressed. Overexpressed SNHG20 was markedly interrelated with the lymph node invasion and TNM stage. In addition, it could be used as indicator to evaluate the prognosis of patients. SNHG20 sponging miR-520f-3p could accelerate the proliferation of CCA tumor cells. MiR-520f-3p acted as a tumor suppressor in CCA and could also serve as a prognostic indicator. Abolition of miR-520f-3p caused an antagonistic effect and diminished the impacts of SNHG20 knockdown. SNHG20 combined with miR-520f-3p could better predict the prognosis of CCA patients. Conclusion: These data confirmed the knockdown SNHG20 expression in CCA could inhibit the proliferation by means of sponging miR-520f-3p.

Exploring the mechanism of LncRNA CASC15 affecting hepatocellular carcinoma through miRNA

This study aimed to determine the potential mechanisms through which long noncoding (Lnc) RNA cancer susceptibility candidate 15 (CASC15) affects hepatocellular carcinoma (HCC). We retrieved HCC RNA-seq and clinical information from the UCSC Xena database. The differential expression (DE) of CASC15 was detected. Overall survival was analyzed using Kaplan-Meier (K-M) curves. Molecular function and signaling pathways affected by CASC15 were determined using Gene Set Enrichment Analysis. Associations between CASC15 and the HCC microenvironment were investigated using immuno-infiltration assays. A differential CASC15-miRNA-mRNA network and HCC-specific CASC15-miRNA-mRNA ceRNA network were constructed. The overexpression of CASC15 in HCC tissues was associated with histological grade, clinical stage, pathological T stage, poor survival, more complex immune cell components, and 12 immune checkpoints. We identified 27 DE miRNAs and 270 DE mRNAs in the differential CASC15-miRNA-mRNA network, and 10 key genes that were enriched in 12 cancer-related signaling pathways. Extraction of the HCC-specific CASC15-miRNA-mRNA network revealed that IGF1R, MET, and KRAS were associated with HCC progression and occurrence. Our bioinformatic findings confirmed that CASC15 is a promising prognostic biomarker for HCC, and elevated levels in HCC are associated with the tumor microenvironment. We also constructed a disease-specific CASC15-miRNA-mRNA regulatory ceRNA network that provides a new perspective for the precise indexing of patients with elevated levels of CASC15.

Molecular regulation of hypoxia through the lenses of noncoding RNAs and epitranscriptome

Cells maintain homeostasis in response to environmental stress through specific cell stress responses. Hypoxic stress, well known to be associated with diverse solid tumors, is one of the main reasons for cancer-related mortality. Although cells can balance themselves well during hypoxic stress, the underlying molecular mechanisms are not well understood. The enhanced appreciation of diverse roles played by noncoding transcriptome and epigenome in recent years has brought to light the involvement of noncoding RNAs and epigenetic modifiers in hypoxic regulation. The emergence of techniques like deep sequencing has facilitated the identification of large numbers of long noncoding RNAs (lncRNAs) that are differentially regulated in various cancers. Similarly, proteomic studies have identified diverse epigenetic modifiers such as HATs, HDACs, DNMTs, polycomb groups of proteins, and their possible roles in the regulation of hypoxia. The crosstalk between lncRNAs and epigenetic modifiers play a pivotal role in hypoxia-induced cancer initiation and progression. Besides the lncRNAs, several other noncoding RNAs like circular RNAs, miRNAs, and so forth are also expressed during hypoxic conditions. Hypoxia has a profound effect on the expression of noncoding RNAs and epigenetic modifiers. Conversely, noncoding RNAs/epigenetic modifies can regulate the hypoxia signaling axis by modulating the stability of the hypoxia-inducible factors (HIFs). The focus of this review is to illustrate the molecular orchestration underlying hypoxia biology, especially in cancers, which can help in identifying promising therapeutic targets in hypoxia-induced cancers. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability RNA in Disease and Development > RNA in Disease RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.

The interplay of long noncoding RNAs and hepatitis B virus

Hepatitis B Virus (HBV) infections remain a major global health burden with an estimated 296 million people living with a chronic infection and 884,000 HBV-related deaths annually. Notably, patients with a chronic hepatitis B (CHB) infection are at a 30-fold greater risk of developing hepatocellular carcinoma (HCC), the most common type of primary liver cancer, which is the 3rd deadliest cancer worldwide. Several groups have assessed HBV-related aberrant expression of host-cell long noncoding RNAs (lncRNAs) and how altered expression of specific lncRNAs affects HBV replication and progression to associated disease states. Given the challenges in establishing effective HBV models and analyzing transcriptomic data, this review focuses on lncRNA expression data primarily collected from clinical patient samples and primary human hepatocytes, with the subsequent mechanism of action analysis in cell lines or other model systems. Ultimately, understanding HBV-induced lncRNA-expression dysregulation could lead to new treatments and biomarkers for HBV infection and its associated diseases.

MSF-UBRW: An Improved Unbalanced Bi-Random Walk Method to Infer Human lncRNA-Disease Associations

Long-non-coding RNA (lncRNA) is a transcription product that exerts its biological functions through a variety of mechanisms. The occurrence and development of a series of human diseases are closely related to abnormal expression levels of lncRNAs. Scientists have developed many computational models to identify the lncRNA-disease associations (LDAs). However, many potential LDAs are still unknown. In this paper, a novel method, namely MSF-UBRW (multiple similarities fusion based on unbalanced bi-random walk), is designed to explore new LDAs. First, two similarities (functional similarity and Gaussian Interaction Profile kernel similarity) of lncRNAs are calculated and fused linearly, also for disease data. Then, the known association matrix is preprocessed. Next, the linear neighbor similarities of lncRNAs and diseases are calculated, respectively. After that, the potential associations are predicted based on unbalanced bi-random walk. The fusion of multiple similarities improves the prediction performance of MSF-UBRW to a large extent. Finally, the prediction ability of the MSF-UBRW algorithm is measured by two statistical methods, leave-one-out cross-validation (LOOCV) and 5-fold cross-validation (5-fold CV). The AUCs of 0.9391 in LOOCV and 0.9183 (±0.0054) in 5-fold CV confirmed the reliable prediction ability of the MSF-UBRW method. Case studies of three common diseases also show that the MSF-UBRW method can infer new LDAs effectively.

Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma

The tumor microenvironment (TME) is a well-recognized system that plays an essential role in tumor initiation, development, and progression. Intense intercellular communication between tumor cells and other cells (especially macrophages) occurs in the TME and is mediated by cell-to-cell contact and/or soluble messengers. Emerging evidence indicates that noncoding RNAs (ncRNAs) are critical regulators of the relationship between cells within the TME. In this review, we provide an update on the regulation of ncRNAs (primarily micro RNAs [miRNAs], long ncRNAs [lncRNAs], and circular RNAs [circRNAs]) in the crosstalk between macrophages and tumor cells in hepatocellular carcinoma (HCC). These ncRNAs are derived from macrophages or tumor cells and act as oncogenes or tumor suppressors, contributing to tumor progression not only by regulating the physiological and pathological processes of tumor cells but also by controlling macrophage infiltration, activation, polarization, and function. Herein, we also explore the options available for clinical therapeutic strategies targeting crosstalk-related ncRNAs to treat HCC. A better understanding of the relationship between macrophages and tumor cells mediated by ncRNAs will uncover new diagnostic biomarkers and pharmacological targets in cancer.

Role of metformin in functional endometrial hyperplasia and polycystic ovary syndrome involves the regulation of MEG3/miR‑223/GLUT4 and SNHG20/miR‑4486/GLUT4 signaling

Metformin (MET) can effectively treat endometrial hyperplasia (EH), and the expression of glucose transporter type 4 insulin-responsive (GLUT4) is closely associated with the development of EH. The present study aimed to verify the effect of MET in functional EH and polycystic ovary syndrome (PCOS). H&E staining was performed to analyze the severity of EH, and immunohistochemistry was performed to evaluate the expression of GLUT4 in the endometrium of PCOS rats. Reverse transcription-quantitative PCR was used to calculate the expression of long non-coding (lnc)RNA-maternally expressed gene 3 (MEG3), lncRNA-small nucleolar RNA host gene 20 (SNHG20), GLUT4 mRNA, microRNA (miR)-223 and miR-4486. Sequence analysis and luciferase assays were performed to explore the regulatory relationship among certain lncRNAs, miRNAs and target genes. EH in PCOS rats was efficiently inhibited by MET administration. The increased expression of GLUT4 in PCOS rats was attenuated by MET treatment. Moreover, the expression levels of lncRNA-MEG3 and lncRNA-SNHG20 were significantly inhibited in the endometrium of PCOS rats. MET treatment also showed remarkable efficiency in restoring the expression of lncRNA-MEG3 and lncRNA-SNHG20. Meanwhile, the expression levels of miR-223 and miR-4486 were notably elevated in the endometrium of PCOS rats, while MET treatment reduced the expression of miR-223 and miR-4486 in PCOS rats. Furthermore, a luciferase assay confirmed the inhibitory relationship between miR-223 and lncRNA-MEG3/GLUT4 expression, as well as between miR-4486 and lncRNA-SNHG20/GLUT4 expression. GLUT4 knockdown restored the decreased viability of HCC-94 cells induced by overexpression of lncRNA-MEG3. To conclude, MET exhibited a therapeutic effect in the treatment of EH by modulating the lncRNA-MEG3/miR-223/GLUT4 and lncRNA-SNHG20/miR-4486/GLUT4 signaling pathways. This work provides mechanistic insight into the development of EH.

Identification of m6A-Related lncRNA to Predict the Prognosis of Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. In the past decades, HCC treatment has achieved great progress; however, the overall prognosis remains poor. Therefore, it is the need of the hour to identify new prognostic biomarkers which can advance our understanding related to the underlying molecular mechanism of adverse prognosis and apply them to clinical work in prognosis prediction. In the present study, data of 576 HCC patients and 292 normal control cases from TCGA and ICGC databases were enrolled to our bioinformatic analysis. SNHG1 and SNHG3 were identified as overlapping genes in TCGA and ICGC databases using Pearson correlation analysis and univariate Cox regression analysis. Further, we used the median of the SNHG1 and SNHG3 expression values as the cutoff values to define the HCC patient groups with high or low expression level. The subsequent analysis revealed that abnormal high expression of SNHG1 or SNHG3 affected the immune infiltration patterns and the crosstalk among immune cells. Moreover, high expression of SNHG1 or SNHG3 resulted in drug resistant to AKT inhibitor VII, bexarotene, bicalutamide, dasatinib, erlotinib, and gefitinib. In addition, lower tumor neoantigen burden was observed in high SNHG1 or SNHG3 group. Further, we found significant relation between the aberrant upregulation of SNHG1 and SNHG3 in tumor grade and stage. We established a nomogram to systematically predict the 5- and 8-year overall survival of liver cancer patients with good accuracy. Finally, the in vitro assays suggest that SNHG1 and SNHG3 promote the proliferative, migratory, and invasive abilities of HCC cells.

High expression of C10orf91 and LINC01224 in hepatocellular carcinoma and poor prognosis

BACKGROUND

The dysregulation of long non-coding RNAs (lncRNAs) has been implicated roles in the pathogenesis of many human diseases, including hepatic diseases. Several lncRNAs have been associated with the progression of hepatocellular carcinoma (HCC), but their function as diagnostic markers for liver cancer remain to be determined.

OBJECTIVE

This study aimed to identify the potential diagnostic markers for liver cancer.

METHODS

The Cancer Genome Atlas (TCGA) database was used to obtain the gene transcriptome data of liver cancer. In addition, this study enrolled 70 liver cancer patients admitted to the Yiwu Central Hospital and 50 healthy people who concurrently underwent physical examinations from February 2017 to January 2020. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression of C10orf91 and LINC01224 in the patients' tissues and serum. A 5-year follow-up was conducted for survival observation. The potential and targeted miRs of C10orf91 and LINC01224 were predicted by online database for miRNA target prediction. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted and competing endogenous RNA (ceRNA) network was plotted.

RESULTS

A total of 175 differentially expressed lncRNAs were screened out, of which 173 were upregulated and 2 were downregulated. C10orf91, and LINC01224 were independent prognostic factors for liver cancer (P<0.05). C10orf91 and LINC01224 had diagnostic value for differentiating liver cancer, tumor node metastasis (TNM) staging, and lymphatic metastasis. GO and KEGG enrichment analysis showed that C10orf91 and LINC01224 were involved in 23 significant biological functions and 35 significant signal transduction pathways respectively.

CONCLUSION

C10orf91 and LINC01224 are highly expressed in liver cancer patients withpoor prognosis.

Long non-coding RNA small nucleolar RNA host genes: functions and mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors of the digestive system, with a high degree of malignancy. Although treatment methods are constantly improving, the mortality of patients is still very high, and the small nucleolar RNA host gene (SNHG) plays an important role in the occurrence and development of cancer. It can activate downstream signaling molecules by acting on microRNA and microRNA target genes, promote the proliferation, invasion, and migration of HCC cells, and provide a new molecular target for the treatment of HCC. At present, the molecular mechanisms of HCC remain unclear. In this study, the mechanism and signaling pathway of SNHG in HCC are reviewed, which provides a theoretical basis for the clinical treatment of HCC.

LncRNA–miRNA–mRNA Networks of Gastrointestinal Cancers Representing Common and Specific LncRNAs and mRNAs

Gastrointestinal (GI) cancers are responsible for approximately half of cancer-related deaths, highlighting the need for the identification of distinct and common features in their clinicopathological characteristics. Long ncRNA (lncRNAs), which are involved in competitive endogenous RNA (ceRNA) networks with critical roles in biological processes, constitute a substantial number of non-coding RNAs. Therefore, our study aimed to investigate the similarities and differences in the ceRNA networks of The Cancer Genome Atlas (TCGA)-GI cancers. We performed a comprehensive bioinformatics analysis of ceRNA networks for TCGA-GI cancers in terms of the deferential mRNA, lncRNA, and miRNA expression levels, ceRNA networks, overall survival analysis, correlation analysis, pathological cancer stages, and gene set enrichment analysis. Our study revealed several common and distinct mRNAs and lncRNAs with prognostic values in these networks. It was specifically noteworthy that MAGI2-AS3 lncRNA was found to be shared in almost all GI cancers. Moreover, the most common shared mRNAs between GI cancers were MEIS1, PPP1R3C, ADAMTSL3, RIPOR2, and MYLK. For each cancer ceRNA network, we found that the expression level of a number of lncRNAs and mRNAs was specific. Furthermore, our study provided compelling evidence that several genes, most notably KDELC1, can act as novel proto-oncogenes in cancers. This, in turn, can highlight their role as new prognostic and therapeutic targets. Moreover, we found cell cycle and extracellular matrix structural constituent as the top shared KEGG and molecular function, respectively, among GI cancers. Our study revealed several known lncRNAs and known and unknown mRNAs in GI cancers with diagnostic and prognostic values.

Long noncoding RNA SNHG20 regulates cell migration, invasion, and proliferation via the microRNA-19b-3p/RAB14 axis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common digestive tumors, which has high mortality rate. Long non-coding RNAs (lncRNA) and MicroRNAs (miRNAs) are associated with the cell cycle and differentiation during the occurrence and development of malignant tumors. This research aimed to investigate the effects of lncRNA SNHG20 on the progress of oral squamous cell carcinoma (OSCC) cells. Ninety pairs of tumor tissues and paracancerous tissues were collected from patients with OSCC and the CAL27 and SCC25 OSCC cells were selected for the following experiments. RT-qPCR was used for detecting the expression of SNHG20, miR-19b-3p, and RAB14. Western blotting was used to detect the protein levels of RAB14. MTT assay was employed to assess cell proliferation. Transwell assay was used to determine the cell migration and invasion abilities. Furthermore, luciferase reporter and RNA pull-down assays were used to verify the binding of SNHG20/RAB14 to miR-19b-3p. Then, the function of the SNHG20/miR-19b-3p/RAB14 axis in OSCC was explored. The results indicated that lncRNA SNHG20 was upregulated in the tissues. Furthermore, bioinformatic analysis showed that both SNHG20 and RAB14 could bind to miR-19b-3p. RAB14 was upregulated, and miR-19b-3p was downregulated in the tissues. The knockdown of SNHG20 inhibited cell proliferation, migration, and invasion. Contrarily, the knockdown of miR-19b-3p reversed the effects of si-SNHG20 on cell proliferation, migration, and invasion, and the overexpression of RAB14 reversed the effects of miR-19b-3p mimic on the cell biological functions. LncRNA SNHG20 affects cell proliferation, migration, and invasion via the miR-19b-3p/RAB14 axis in OSCC.

Long Noncoding RNAs in Gastrointestinal Cancer: Tumor Suppression Versus Tumor Promotion

Approximately 80% of the human genome harbors biochemical marks of active transcription that its majority transcribes to noncoding RNAs, namely long noncoding RNAs (lncRNAs). LncRNAs are heterogeneous RNA transcripts that regulate critical biological processes such as cell survival and death. They involve in the progression of different cancers by affecting transcriptional and post-transcriptional modifications as well as epigenetic control of numerous tumor suppressors and oncogenes. Recent findings show that aberrant expression of lncRNAs is associated with tumor initiation, progression, invasion, and overall survival of patients with gastrointestinal (GI) cancers. Some lncRNAs play as tumor suppressors in all GI cancers, but others play as tumor promoters. However, some other lncRNAs might function as a tumor suppressor in one GI cancer, but as a tumor promoter in another GI cancer type. This fact highlights possible context dependency of the expression patterns and roles of at least some lncRNAs in GI cancer development and progression. Here, we review the functional relation of lncRNAs involved in the development and progression of GI cancer by focusing on their roles as tumor suppressor and tumor promoter genes.

Long non-coding RNAs as the regulators and targets of macrophage M2 polarization

Macrophages are immune cells with high heterogeneity and plasticity. M2 polarization is one extreme of the well-established phenotypes of macrophage polarization, and involves in diverse biological processes. The polarization process is initiated at the command of numerous components. Long non-coding RNAs (lncRNAs) are RNAs longer than 200 nucleotides with limited protein-coding capacity. Recent studies have revealed a newly found subset of lncRNAs engaged in the M2 polarization and their potent and multifunctional roles in developing diseases. By interfering with specific signaling pathways and altering the active mode, acting as the sponges of microRNAs or decoys of transcription factors, lncRNAs prompted macrophages to an M2 phenotype. Further, lncRNAs can bind to the genome to regulate the chromatin dynamics or work as a platform for protein complexes tether. Exosomal lncRNAs can also orchestrate the polarization in a paracrine way. To make it easier to interpret the roles of lncRNAs in the M2 polarization, we review the reported lncRNAs according to the underlying mechanisms. Moreover, we discuss the possibilities of targeting macrophages' M2 polarization using the oligonucleotides drugs or clustered regularly interspaced palindromic repeats (CRISPR) technologies to provoke wisdom on the therapeutic strategies.

Long noncoding RNA-SNHG20 promotes silica-induced pulmonary fibrosis by miR-490-3p/TGFBR1 axis

Silicosis is a universal occupational disease, which is caused by long-term crystalline silica exposure. Recent studies have shown that noncoding RNAs participate in diverse pathological cellular pathways. However, the precise regulation mechanism remains limited in silicosis. Here, we established a silica-induced mouse fibrosis model (all mice received a one-time intratracheal instillation with 50 mg/kg of silica in 0.05 mL sterile saline). MiR-490-3p was significantly downregulated in silica-induced fibrotic mouse lung tissues and TGF-β1 treated fibroblasts. Moreover, overexpressed miR-490-3p could relieve silica-induced lung fibrosis in vivo, and prevent the process of fibroblast-to-myofibroblast transition(FMT)in vitro. Mechanistically, TGFBR1 was one of the major target genes of miR-490-3p, and tightly associated with the process of fibroblasts activation. SNHG20, as opposed to miR-490-3p expression, was elevated in TGF-β1-treated fibroblast cell lines and contributed to decreased levels of miR-490-3p. Taken together, these data indicated that miR-490-3p plays a key role in silica-induced pulmonary fibrosis. Our results suggested that SNHG20/miR-490-3p/TGFBR1 axis may provide a new treatment target of pulmonary fibrosis.

The potential of long noncoding RNAs for precision medicine in human cancer

Precision medicine promises to better classify patients by individual clinical and biological biomarkers, which may provide an accurate assessment of disease risk, diagnosis, prognosis and treatment response. Cancer frequently displays substantial inter-tumor and intra-tumor heterogeneity and hence oncology is well suited for application of precision approaches. Recent studies have demonstrated that dysregulated lncRNAs play pivotal roles in tumor heterogeneity. In this review, attention is focused on the potential applications of lncRNAs as biomarker candidates for cancer risk evaluation, detection, surveillance and prognosis. LncRNAs are often stable in clinical samples and easily detected. The functional implications and therapeutic potential of targeting lncRNAs in human cancer are further discussed. Finally, existing deficiencies and future perspectives in translating fundamental lncRNA knowledge into clinical practice are highlighted.

Long non-coding RNA SNHG20 promotes ovarian cancer development by targeting microRNA-338-3p to regulate MCL1 expression

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs/miRs) were reported to be associated with the development of ovarian cancer (OC). Increasing evidence demonstrated that lncRNA SNHG20 and miR-338-3p were involved in OC. However, the functional mechanism of lncRNA SNHG20 and miR-338-3p in OC development remains unknown. The expression of SNHG20, miR-338-3p and myeloid cell leukemia 1 (MCL1) was detected by reverse transcription-quantitative PCR. MTT assay, flow cytometry and transwell migration and invasion assays were used to assess cell proliferation, apoptosis, migration and invasion, respectively. The relative protein expression was detected by western blot analysis. The interaction between miR-338-3p and SNHG20 or MCL1 was predicted by starBase v3.0, and subsequently confirmed by dual-luciferase reporter assay. Besides, mouse xenograft assay was carried out to explore the effect of SNHG20 on tumor growth in vivo. The levels of SNHG20 and MCL1 were upregulated, while miR-338-3p level was downregulated in OC tissues and cells. SNHG20 knockdown repressed OC cell proliferation, migration, invasion and epithelial-mesenchymal transition, and induced apoptosis. Interestingly, SNHG20 targeted miR-338-3p to regulate MCL1 expression. miR-338-3p depletion or MCL1 overexpression could reverse the effects of SNHG20 knockdown on OC cells. Besides, SNHG20 knockdown impeded tumor growth in vivo. In conclusion, the present study demonstrated that SNHG20 regulates OC development via modulation of the miR-338-3p/MCL1 axis, providing the theoretical basis for the treatment of OC.

Comprehensive analysis of partial epithelial mesenchymal transition-related genes in hepatocellular carcinoma

Increasing evidence has revealed that cancer cells undergoing an intermediate state, partial epithelial mesenchymal transition (p‐EMT), tend to metastasize rather than complete EMT. We performed a comprehensive analysis of E‐cadherin and 25 p‐EMT‐related genes in HCC to explore the roles and regulatory mechanisms of them in HCC. We analysed E‐cadherin and 25 p‐EMT‐related genes in HCC and constructed an mRNA‐miRNA‐lncRNA ceRNA subnetwork containing p‐EMT‐related genes by bioinformatic approaches. IHC was used to identify the protein expression of key p‐EMT‐related genes, P4HA2, ITGA5, MMP9, MT1X and SPP1. Complete EMT is not necessary for HCC progression. Overexpression of P4HA2, ITGA5, MMP9, SPP1 and down‐regulation of MT1X were found in HCC tissues, which were significantly associated with poor prognosis of HCC patients. By means of stepwise reverse prediction and validation from mRNA to lncRNA, an mRNA‐miRNA‐lncRNA ceRNA subnetwork correlated with HCC prognosis was identified by expression and survival analysis. This study implied that key p‐EMT‐related genes P4HA2, ITGA5, MMP9, MT1X, SPP1 could be prognostic biomarkers and potential targets of therapy for HCC patients. We constructed an mRNA‐miRNA‐lncRNA subnetwork containing p‐EMT‐related genes successfully, among which each component might be utilized as a prognostic biomarker of HCC.

The prognostic significance of long non-coding RNAs in hepatocellular carcinoma: An updated meta-analysis

BACKGROUND

Recently, many studies have demonstrated that long non-coding RNAs (lncRNAs) are abnormally expressed in hepatocellular carcinoma (HCC) and may serve as a potential molecular biomarker to evaluate the prognosis of hepatocellular carcinoma. Therefore, we accomplished a meta-analysis built on current studies to assess the prognostic value of lncRNAs in hepatocellular carcinoma.

METHODS

The PubMed database was carefully searched to collect all eligible studies until February 20, 2019. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) of the overall survival, relapse-free survival, and progression-free survival were calculated to evaluate the prognostic significance of lncRNAs expression in hepatocellular carcinoma using Stata12.0 software. Heterogeneity, sensitivity analysis, and publication bias were also evaluated.

RESULTS

The results showed that the expression level of lncRNAs was significantly correlated with clinical outcomes. Abnormally expressed lncRNAs predicted poor overall survival (HR=2.19, 95% CI: 1.99-2.42, P<0.001; I²=44.7%, P=0.005), relapse-free survival (HR=2.68, 95% CI: 1.74-4.14, P<0.001; I²=0.0%, P=0.763) and progression-free survival of hepatocellular carcinoma patients (HR=2.44, 95% CI: 1.53-3.89, P<0.001; I²=0.0%, P=0.336). Statistical significance was also noted in subgroup meta-analyses that were stratified by follow-up time, cutoff value, and quality score. Moreover, the pooled results indicated that lncRNAs expression was significantly associated with tumor size (HR=1.48, 95% CI: 1.24-1.79), tumor number (HR=1.34, 95% CI: 1.08-1.66), and tumor node metastasis stage (HR=2.10, 95% CI: 1.48-2.99), but not liver cirrhosis and tumor differentiation (P>0.05).

CONCLUSIONS

This meta-analysis indicates that lncRNAs are strongly associated with prognosis in hepatocellular carcinoma and may serve as a promising indicator for prognostic evaluation of patients with hepatocellular carcinoma. But larger clinical studies are needed to verify its feasibility.

Long non‑coding RNA SNHG20 promotes colorectal cancer cell proliferation, migration and invasion via miR‑495/STAT3 axis

Colorectal cancer (CRC) is one of the primary causes of cancer-associated mortality worldwide. However, the potential molecular mechanism of CRC progression remains unknown. Long non-coding RNA small nucleolar RNA host gene 20 (SNHG20) has been demonstrated to be involved in the development and progression of a variety of tumors, including CRC. However, the involvement of SNHG20 in CRC progression remains unclear. The aim of the present study was to investigate the functional role and molecular mechanism of SNHG20 in CRC progression. In the present study, SNHG20 expression was found to be significantly upregulated in CRC tissues and cell lines. Association analysis indicated that high SNHG20 expression was significantly association with greater tumor size (P=0.014), tumor invasion depth (P=0.019), positive lymph node status (P=0.022), distant metastasis (P=0.017) and advanced tumor node metastasis stage (P=0.038). Loss-of-function experiments indicated that SNHG20 knockdown could significantly suppress proliferation, migration and invasion in vitro. Notably, SNHG20 knockdown significantly inhibited tumor growth and lung metastasis in vivo. Bioinformatics analysis and luciferase reporter assays confirmed that microRNA (miR)-495 was a direct target of SNHG20. Rescue assays indicated that miR-495 inhibitor reversed the suppressive effects of SNHG20 knockdown on CRC progression. Moreover, STAT3 was identified as a downstream target of miR-495 in CRC. STAT3 overexpression partially rescued the inhibitory effects of SNHG20 knockdown on CRC progression. Taken together, the results revealed that SNHG20 facilitated CRC progression by regulating STAT3 expression and by sponging miR-495.

An Integrating Immune-Related Signature to Improve Prognosis of Hepatocellular Carcinoma

Growing evidence suggests that the superiority of long noncoding RNAs (lncRNAs) and messenger RNAs (mRNAs) could act as biomarkers for cancer prognosis. However, the prognostic marker for hepatocellular carcinoma with high accuracy and sensitivity is still lacking. In this research, a retrospective, cohort-based study of genome-wide RNA-seq data of patients with hepatocellular carcinoma was carried out, and two protein-coding genes (GTPBP4, TREM-1) and one lncRNA (LINC00426) were sorted out to construct an integrative signature to predict the prognosis of patients. The results show that both the AUC and the C-index of this model perform well in TCGA validation dataset, cross-platform GEO validation dataset, and different subsets divided by gender, stage, and grade. The expression pattern and functional analysis show that all three genes contained in the model are associated with immune infiltration, cell proliferation, invasion, and metastasis, providing further confirmation of this model. In summary, the proposed model can effectively distinguish the high- and low-risk groups of hepatocellular carcinoma patients and is expected to shed light on the treatment of hepatocellular carcinoma and greatly improve the patients' prognosis.

Identification of prognostic biomarkers of hepatocellular carcinoma via long noncoding RNA expression and copy number alterations

Aim: This study aimed to identify long noncoding RNAs (lncRNAs) with potential to be prognostic biomarkers of hepatocellular carcinoma (HCC) by analyzing copy number alterations (CNAs). Methods: RNA Sequencing data of 369 HCC patients was downloaded from The Cancer Genome Atlas database and analyzed with a series of systematic bioinformatics methods. Results: LncRNA-CNA association analysis revealed that many lncRNAs were located in sites frequently amplified or deleted. Three upregulated lncRNAs (LINC00689, SNHG20 and MAFG-AS1) with copy amplification and one downregulated lncRNA TMEM220-AS1 with copy deletion were associated with poor prognosis of HCC. Conclusion: This study reveals that differentially expressed lncRNAs correlate with CNAs in HCC. Moreover, the differentially expressed lncRNAs and their copy amplification/deletions could be promising prognostic biomarkers of HCC.

Prognostic and clinicopathological significance of SNHG20 in human cancers: a meta-analysis

Background

It has been widely reported that the expression levels of SNHG20 are elevated in diverse types of cancers, indicating that SNHG20 may participate in cancer initiation and development. Besides, accumulating evidence reveals that SNHG20 overexpression is also connected with poor clinical outcomes among cancer patients. Herein, we carry out a systematic meta-analysis to further determine the prognostic and clinical significance of SNHG20 expression in various human cancers.

Methods

Qualifying publications were selected by searching for keywords in PubMed, Embase, Web of Science and Cochrane Library databases, up to September 1, 2019. Pooled hazard ratio (HR) or odds ratio (OR) with corresponding 95% confidence interval (CI) was computed to estimate the strength of association between SNHG20 and survival of cancer patients or clinicopathology using Stata 14.0 software.

Results

In total, 15 studies encompassing 1187 patients met the inclusion criteria were ultimately enrolled for analysis. According to the meta-analysis, patients with high SNHG20 expression were markedly linked to poorer overall survival (OS) (pooled HR = 2.47, 95% CI 2.05–2.98, P = 0.000) and disease-free survival/recurrence-free survival/progression-free survival (DFS/RFS/PFS) (pooled HR = 2.37, 95% CI 1.60–3.51, P = 0.000). Additionally, regarding clinicopathology of patients, enhanced SNHG20 was correlated with advanced tumour‐node‐metastasis (TNM) stage (OR = 2.80, 95% CI 2.00–3.93, P = 0.000), larger tumor size (OR = 3.08, 95% CI 2.11–4.51, P = 0.000), positive lymph nodes metastasis (OR = 2.99, 95% CI 2.08–4.31, P = 0.000), higher tumor stage (OR = 4.51, 95% CI 2.17–9.37, P = 0.000) and worse histological grade (OR = 1.95, 95% CI 1.44–2.63, P = 0.000), but not with gender, smoking status or distant metastasis.

Conclusions

Up-regulated SNHG20 expression is ubiquitous in different kinds of cancers. Moreover, up-regulated SNHG20 expression is capable of serving as an innovative predictive factor of inferior clinical outcomes in cancer patients. Nevertheless, higher-quality multicenter studies are required to corroborate our results.

Knockdown SNHG20 Suppresses Nonsmall Cell Lung Cancer Development by Repressing Proliferation, Migration and Invasion, and Inducing Apoptosis by Regulating miR-2467-3p/E2F3

Background: Lung cancer was one of the most common malignant tumors worldwide. In China, lung cancer has become the leading reason of malignant tumors-related mortality in urban population, whereas nonsmall cell lung cancer (NSCLC) represented at least 80% of all lung cancers with poor 5-year survival rate. Long noncoding RNA (lncRNA) small nucleolar RNA host gene 20 (SNHG20) was reported to be associated with NSCLC, but the regulatory mechanisms of SNHG20 in NSCLC needed further investigation. Methods: The abundances of SNHG20 and E2F transcription factor 3 (E2F3) in NSCLC tissues and cells were measured with real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assays. 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT) was applied to detect cells proliferation, whereas flow cytometry analysis was used to monitor cell apoptosis. In addition, cells capabilities of migratory and invasion were assessed with transwell assay. The association among miR-2467-3p, SNHG20, and E2F3 was analyzed by dual-luciferase reporter assay. The related protein expression levels were determined by Western blot. Results: SNHG20 and E2F3 was upregulation in NSCLC tissues and cell lines. Mechanical experiment displayed that knockdown of SNHG20 or E2F3 silencing could inhibit proliferation, motility, and improve apoptosis in NSCLC cell lines. Restored expression of E2F3 could effectively reverse reduction of proliferation, motility, and promotion of apoptosis caused by SNHG20 silencing in NSCLC cells. Besides, SNHG20 activated protein kinase B (AKT) signaling pathway and increased E2F3 level in NSCLC cells through targeting miR-2467-3p. Conclusion: SNHG20 contributed to NSCLC development through mediating AKT signaling pathway and sponging miR-2467-3p to elevate E2F3 expression in NSCLC cells.

Weighted Gene Coexpression Network Analysis Reveals the Dynamic Transcriptome Regulation and Prognostic Biomarkers of Hepatocellular Carcinoma

This study was aimed at revealing the dynamic regulation of mRNAs, long noncoding RNAs (lncRNAs), and microRNAs (miRNAs) in hepatocellular carcinoma (HCC) and to identify HCC biomarkers capable of predicting prognosis. Differentially expressed mRNAs (DEmRNAs), lncRNAs, and miRNAs were acquired by comparing expression profiles of HCC with normal samples, using an expression data set from The Cancer Genome Atlas. Altered biological functions and pathways in HCC were analyzed by subjecting DEmRNAs to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Gene modules significantly associated with disease status were identified by weighted gene coexpression network analysis. An lncRNA-mRNA and an miRNA-mRNA coexpression network were constructed for genes in disease-related modules, followed by the identification of prognostic biomarkers using Kaplan-Meier survival analysis. Differential expression and association with the prognosis of 4 miRNAs were verified in independent data sets. A total of 1220 differentially expressed genes were identified between HCC and normal samples. Differentially expressed mRNAs were significantly enriched in functions and pathways related to “plasma membrane structure,” “sensory perception,” “metabolism,” and “cell proliferation.” Two disease-associated gene modules were identified. Among genes in lncRNA-mRNA and miRNA-mRNA coexpression networks, 9 DEmRNAs and 7 DEmiRNAs were identified to be potential prognostic biomarkers. MIMAT0000102, MIMAT0003882, and MIMAT0004677 were successfully validated in independent data sets. Our results may advance our understanding of molecular mechanisms underlying HCC. The biomarkers may contribute to diagnosis in future clinical practice.

RNA N6-Methyladenosine-Related Gene Contribute to Clinical Prognostic Impact on Patients With Liver Cancer

Liver cancer (LC) is the fourth leading cause of cancer-related deaths worldwide. There is an urgent need to identify novel and reliable prognostic biomarkers for LC in order to improve patient outcomes. N6-methyladenosine (m6A) is the most common internal modification in eukaryotic mRNA and has been associated with various cancers, although its roles in the prognosis of LC remains to be elucidated. We analyzed the expression profiles of 15 m6A-related genes in the International Cancer Genome Consortium (ICGC) LIRI-JP dataset, and applied consensus clustering to stratify LC patients into two subgroups (Cluster 1 and Cluster 2). Cluster1 was significantly correlated to lower tumor stage and longer overall survival (OS). Gene set enrichment analysis showed that tumorigenic markers, including DNA repair, E2F targets, G2M checkpoint, and MYC targets V1, were enriched in Cluster2. We then constructed a prognostic risk model using three m6A-related genes that were identified as independent factors affecting OS. The nomogram based on the risk model score indicated good performance in predicting the 1-, 2- and 3-year survival of the LC patients. In conclusion, m6A-related genes are potential prognostic markers and therapeutic targets for LC.

PD-1/PD-L1 pathway: current researches in cancer

Cancer immunotherapy has been accompanied by promising results over the past few years. Programmed Cell Death Protein 1 (PD-1) plays a vital role in inhibiting immune responses and promoting self-tolerance through modulating the activity of T-cells, activating apoptosis of antigen-specific T cells and inhibiting apoptosis of regulatory T cells. Programmed Cell Death Ligand 1 (PD-L1) is a trans-membrane protein that is considered to be a co-inhibitory factor of the immune response, it can combine with PD-1 to reduce the proliferation of PD-1 positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 also plays an important role in various malignancies where it can attenuate the host immune response to tumor cells. Based on these perspectives, PD-1/PD-L1 axis is responsible for cancer immune escape and makes a huge effect on cancer therapy. This review is aimed to summarize the role of PD-1 and PD-L1 in cancer, looking forward to improve the therapy of cancer.

Prognostic value of long non-coding RNA SNHG20 in cancer: A meta-analysis

BACKGROUND

Small nucleolar RNA host gene 20 (SNHG20) is a newly identified long non-coding RNA (lncRNA). Accumulative evidence suggest that SNHG20 is highly related to tumorigenesis. However, whether the levels of SNHG20 can be used for prognosis of patients with different cancer types was unclear. The present study aims to explore the role of SNHG20 in tumor prognosis and its clinical significance.

METHODS

Related articles published before March 14, 2019 were searched in PubMed, Excerpta Medica Database (EMBASE), ISI Web of Science, and China National Knowledge Infrastructure (CNKI). Hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were obtained using Stata 11.0 software and used to for determination of the link between the levels of SNHG20 and overall survival (OS). Fixed or random model was chosen depending on the heterogeneity of the studies. A quality assessment of the included studies was performed according to the Newcastle-Ottawa scale. This study was approved by the Medical Ethics Committee of Xiangya Hospital of Central South University.

RESULTS

After a strict filtering process, a total of 1149 patients from 15 studies were enrolled in this study. Pooled data showed that elevated level of SNHG20 was correlated not only with poor overall survival (HR = 2.49, 95% confidence interval (CI): 2.05-2.98), but also with tumor-node-metastasis stage (TNM) (odds ratio (OR) = 3.32, 95% CI: 2.27-4.86), high histological grade (OR = 2.11, 95% CI: 1.55-2.87), tumor size (OR = 2.92, 95% CI: 2.17-3.91), and lymph node metastasis (OR = 4.48, 95% CI: 2.90-6.92). Of note, there is no significant heterogeneity difference among the studies.

CONCLUSION

Up-regulated SNHG20 predicts unfavorable prognosis for multiple kinds of cancers although further studies are in need to verify its clinical applications.

Can small nucleolar RNA be a novel molecular target for hepatocellular carcinoma?

BACKGROUND

Globally, hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death. Recently, many studies have demonstrated that small nucleolar RNA (snoRNA) was closely related to HCC.

OBJECTIVE

To explore whether snoRNA can be used as a molecular target for HCC.

METHODS

The PubMed, Embase, and Cochrane databases were searched for the published literatures related to snoRNA and HCC until August 12, 2019. After identification, screening, and verification, this study finally included 26 studies correlating small nucleolar RNA host gene (SNHG) and HCC, and 8 studies correlating snoRNA and HCC. Based on the collation of the relevant literature, the correlation network diagram between snoRNAs and HCC was constructed.

RESULTS

The SNHGs, such as SNHG1, SNHG6, SNHG16, and SNHG20 can play varied roles in HCC through different regulatory mechanisms. These SNHGs can promote and inhibit tumorigenesis. SNORD76 can promote the proliferation of tumor tissues and cells in vitro through different pathways. SnoU2_19 and SNORD76 can function through the same pathway. SNHG3, SNHG20, SNHG6, SNORD76, and snoRA47 can modulate epithelial-mesenchymal transition (EMT) to regulate the development of HCC cell or tissue. SNHG16, SNORD76, and SnoU2_19 can regulate the development of HCC through Wnt/β-catenin signaling pathway.

CONCLUSION

snoRNA can regulate the occurrence of HCC by modulating multiple molecular signaling pathways. Hence, snoRNA can be a potential molecular target for HCC.

Identification of circular RNA-microRNA-messenger RNA regulatory network in hepatocellular carcinoma by integrated analysis

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is the most common types of hepatic malignancies. This study aimed to better understand the pathogenesis of HCC and may help facilitate the improvement of the diagnostic of HCC.

METHODS

The mRNA and miRNA expression profiles of HCC, which was retrieved from The Cancer Genome Atlas database, and the circRNA expression profiles of HCC, which was retrieved from Gene Expression Omnibus database, were included in this study to perform an integrated analysis. The differentially expressed mRNAs (DEmRNAs), differentially expressed miRNAs (DEmiRNAs), and differentially expressed circRNAs (DEcircRNAs) were identified, and competing endogenous RNA (ceRNA) (DEcircRNA-DEmiRNA-DEmRNA) regulatory network was conducted. Functional annotation of host gene of DEcircRNAs and DEmRNAs in ceRNA regulatory network was performed. Quantitative real-time polymerase chain reaction validation of the expression of the selected DEmRNAs, DEmiRNAs, and DEcircRNAs was performed.

RESULTS

A total of 2982 DEmRNAs, 144 DEmiRNAs, and 264 DEcircRNAs were obtained. The ceRNA network contained 61 circRNA-miRNA pairs and 1149 miRNA-mRNA pairs, including 48 circRNAs, 30 miRNAs, and 1149 mRNAs. Functional annotation of DEmRNAs in ceRNA regulatory network revealed that these DEmRNAs were significantly enriched in tryptophan metabolism, fatty acid metabolism, and pathways in cancer. Except for ARNT2 and hsa-miR-214-3p, expression of the others in the quantitative real-time polymerase chain reaction results was consistent with that in our integrated analysis, generally.

CONCLUSION

We speculate that hsa_circRNA_104268/hsa-miR-214-3p/E2F2, hsa_circRNA_104168/hsa-miR-139-5p/HRAS, and hsa_circRNA_104769/hsa-miR-93-5p/JUN interaction pairs may play a vital role in HCC. This study expected to provide a novel insight into the pathogenesis and therapy of HCC from the circRNA-miRNA-mRNA network view.

Characterization of Hepatocellular Carcinoma Cell Lines Using a Fractionation-Then-Sequencing Approach Reveals Nuclear-Enriched HCC-Associated lncRNAs

Background: Advances in sequencing technologies have greatly improved our understanding of long noncoding RNA (lncRNA). These transcripts with lengths of >200 nucleotides may play significant regulatory roles in various biological processes. Importantly, the dysregulation of better characterized lncRNAs has been associated with multiple types of cancers, including hepatocellular carcinoma (HCC). There are many studies on altered lncRNA expression levels, very few, however, have focused on their subcellular localizations, from which accumulating evidences have indicated their close relationships to lncRNA functions. A transcriptome-wide investigation of the subcellular distributions of lncRNAs might thus provide new insights into their roles and functions in cancers.

Results: In this study, we subjected eight patient-derived HCC cell lines to subcellular fractionation and independently sequenced RNAs from the nuclear and cytoplasmic compartments. With the integration of tumor and tumor-adjacent RNA-seq datasets of liver hepatocellular carcinoma (LIHC) from The Cancer Genome Atlas (TCGA), de novo transcriptome assembly and differential expression analysis were conducted successively and identified 26 nuclear-enriched HCC-associated lncRNAs shared between the HCC samples and the TCGA datasets, including the reported cancer driver PXN-AS1. The majority of nuclear-enriched HCC-associated lncRNAs were associated with the survival outcomes of HCC patients, exhibited characteristics similar to those of many experimentally supported HCC prognostic lncRNAs, and were co-expressed with protein-coding genes that have been linked to disease progression in various cancer types.

Conclusion: We adopted a fractionation-then-sequencing approach on multiple patient-derived HCC samples and identified nuclear-enriched, HCC-associated lncRNAs that could serve as important targets for HCC diagnosis and therapeutic development. This approach could be widely applicable to other studies into the disease etiologies of lncRNA.

lncRNA SNHG6 functions as a ceRNA to up-regulate c-Myc expression via sponging let-7c-5p in hepatocellular carcinoma

Emerging evidence has revealed that dysregulation of lncRNAs correlate with the development and progression of hepatocellular carcinoma (HCC). In the present study, we globally investigated the expression of SNHG6 in 31 cancer type, and we found that SNHG6 was highly expressed in various cancers, especially in HCC. High expression of SNHG6 was associated with progression and poor prognosis in patients with HCC. Gain of function and loss of function assays showed that SNHG6 promoted HCC cell proliferation. Gene Set Enrichment Analysis (GSEA) and correlation analysis suggested that SNHG6 positively correlated with c-Myc and its downstream targets. Ectopic overexpression of SNHG6 markedly increased the expression of c-Myc and its downstream targets, whereas silencing SNHG6 had the opposite effect on the expression of c-Myc and its downstream targets. Mechanistic assays revealed that SNHG6 acted as a competing endogenous RNA (ceRNA) to sponge let-7c-5p and thereby modulating the depression of c-Myc by let-7c-5p. Taken together, SNHG6 promotes HCC cell proliferation via competitively binding let-7c-5p in hepatocellular carcinoma.

SNHG20: A vital lncRNA in multiple human cancers

Long noncoding RNAs (lncRNAs) act as an initial factor and promoter in different tumors as a kind of ncRNAs. The length of them is >200 nucleotides opposite small ncRNAs. Increasing researches have proved that dysregulation lncRNA has been implicated in tumorigenesis. Small nucleolar RNA host gene 20 (SNHG20), a member of lncRNAs, expresses frequently in cancer types, such as hepatocellular carcinoma, ovarian cancer, colorectal cancer, and bladder cancer, contributing to cancer development and progression by transcriptional or posttranscriptional modifications. Not only does this review show the recent published literature concerning the biological functions but also demonstrates molecular mechanisms of SNHG20 among above multiple malignancies and others.

Integration analysis for novel lncRNA markers predicting tumor recurrence in human colon adenocarcinoma

BACKGROUND

Numerous evidence has suggested that long non-coding RNA (lncRNA) acts an important role in tumor biology. This study focuses on the identification of novel prognostic lncRNA biomarkers predicting tumor recurrence in human colon adenocarcinoma.

METHODS

We obtained the research data from The Cancer Genome Atlas (TCGA) database. The interaction among different expressed lncRNA, miRNA and mRNA markers between colon adenocarcinoma patients with and without tumor recurrence were verified with miRcode, starBase and miRTarBase databases. We established the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network based on the verified association between the selected markers. We performed the functional enrichment analysis to obtain better understanding of the selected lncRNAs. Then we use multivariate logistic regression to identify the prognostic lncRNA markers with covariates. We also generated a nomogram predicting tumor recurrence risk based on the identified lncRNA biomarkers and clinical covariates.

RESULTS

We included 12,727 lncRNA, 1881 miRNA and 47,761 mRNA profiling and clinical features for 113 colon adenocarcinoma patients obtained from the TCGA database. After filtration, we used 37 specific lncRNAs, 60 miRNAs and 148 mRNAs in the ceRNA network analysis. We identified five lncRNAs as prognostic lncRNA markers predicting tumor recurrence in colon adenocarcinoma, in which four of them were identified for the first time. Finally, we generated a nomogram illustrating the association between the identified lncRNAs and the tumor recurrence risk in colon adenocarcinoma.

CONCLUSIONS

The four newly identified lncRNA biomarkers might be potential prognostic biomarkers predicting tumor recurrence in colon adenocarcinoma. We recommend that further clinical and fundamental researches be conducted on the identified lncRNA markers.

Upregulation of long noncoding RNA SNHG20 promotes cell growth and metastasis in esophageal squamous cell carcinoma via modulating ATM-JAK-PD-L1 pathway

Increasing evidence have proved that long noncoding RNAs (lncRNAs) play significant roles in tumorigenesis and development of various cancers. However, the effect of small nucleolar RNA host gene 20 (SNHG20) on the progression of esophageal squamous cell carcinoma (ESCC) remains to be discovered. Herein, we aim to find out the function and the possible mechanism of SNHG20 in ESCC progression. In our study, we demonstrate that SNHG20 is markedly upregulated in ESCC tissues and cell lines. Besides, the level of SNHG20 is closely associated with tumor size, lymph node metastasis, TNM stage, and tumor grade. In addition, SNHG20 level is an independent predictor for clinical outcomes of ESCC patients. Then the gain- and loss-of-function assays reveal that SNHG20 overexpression promotes cell proliferation, migration, invasion, and epithelial-mesenchymal transition as well as represses apoptosis, whereas depletion of SNHG20 exhibits opposite effects. Moreover, we uncover that SNHG20 modulates the expression of ataxia telangiectasia-mutated kinase (p-ATM), p-JAK1/2, and programmed cell death 1 ligand 1 (PD-L1) in ESCC cells and ATM upregulation restores the suppressive effect of SNHG20 inhibition on ESCC progression. Therefore, we conclude that SNHG20 serves as a carcinogen in ESCC by promoting growth and metastasis via ATM-JAK-PD-L1 pathway, supplying a possibly effective therapeutic target for ESCC.

Hepatitis B virus x protein accelerated the proliferation of hepatocellular carcinoma cell through lncRNA SNHG20/PTEN pathway

This study investigated the underlying mechanism of long noncoding RNA (lncRNA) small nucleolar RNA host gene 20 (SNHG20) in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). LncRNA SNHG20 and PTEN expression levels were detected by quantitative real-time polymerase chain reaction and western blot. The proliferation of HCC cells was measured by MTT assay, and the apoptosis of HCC cells was measured by flow cytometry analysis. SNHG20 expression level and HBx protein level were upregulated in HBV(+) group than that of HBV(-) group, whereas PTEN protein level was downregulated in HBV(+) group. Besides, SNHG20 was highly expressed in HBV(+) HCC cells than in HBV(-) HCC cells. SNHG20 expression level was positively associated with HBV x protein (HBx) in HCC cells, and HBx-SNHG20 involved in regulating the proliferation and apoptosis of HCC cells. Moreover, SNHG20 was confirmed to interact with PTEN, which negatively regulated PTEN protein level. Finally, we proved HBx-SNHG20-PTEN signalling pathway involved in the regulation of HCC cell proliferation and apoptosis. In vivo experiments showed SNHG20 knockdown inhibited tumour growth of HBV(+) HCC. HBx promoted the proliferation of HCC cell and reduced the apoptosis of HCC cells through the SNHG20/PTEN signalling pathway.

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.

LncRNA SNHG20 predicts a poor prognosis and promotes cell progression in epithelial ovarian cancer

The long noncoding RNA small nucleolar RNA host gene 20 (SNHG20) has been demonstrated to play a crucial role in cancer progression. However, the functions of SNHG20 in epithelial ovarian cancer (EOC) are not well established. The aim of the present study was to investigate SNHG20 clinical significance and its underlying mechanism in proliferation and metastasis in EOC. The expression level of SNHG20 was identified via in situ hybridization (ISH) and quantitative RT-PCR (qRT-PCR). The proliferative and metastatic capacities by silencing SNHG20 expression in A2780 and CAOV-3 cells were measured by cell counting kit-8 (CCK-8) and transwell assays. The molecular mRNA and protein expressions were examined using qRT-PCR, Western blot, and double immunofluorescent staining. SNHG20 expression was markedly higher in serous EOC tissues than that in adjacent tissues and closely correlated with histological grade and lymph node (LN) status. Patients with high SNHG20 showed a shorter overall survival (OS) and SNHG20 was an independent risk factor for the prognosis of serous EOC. Knockdown of SNHG20 remarkably inhibited EOC cell proliferation, migration, and invasion, which was associated with dysregulation of P21, Cyclin D1, E-cadherin, and Vimentin. These results suggest that SNHG20 may serve as an independent prognostic predictor and function as a noncoding oncogene in EOC progression, which might be a possible novel diagnostic marker and treatment target.

ZRANB2/SNHG20/FOXK1 Axis regulates Vasculogenic mimicry formation in glioma

Background

Glioma is the most common intracranial neoplasm with vasculogenic mimicry formation as one form of blood supply. Many RNA-binding proteins and long non-coding RNAs are involved in tumorigenesis of glioma.

Methods

The expression of ZRANB2, SNHG20 and FOXK1 in glioma were detected by real-time PCR or western blot. The function of ZRANB2/SNHG20/FOXK1 axis in glioma associated with vasculogenic mimicry formation was analyzed.

Results

ZRANB2 is up-regulated in glioma tissues and glioma cells. ZRANB2 knockdown inhibits the proliferation, migration, invasion and vasculogenic mimicry formation of glioma cells. ZRANB2 binds to SNHG20 and increases its stability. Knockdown of SNHG20 reduces the degradation of FOXK1 mRNA by SMD pathway. FOXK1 inhibits transcription by binding to the promoters of MMP1, MMP9 and VE-Cadherin and inhibits vasculogenic mimicry formation of glioma cells.

Conclusions

ZRANB2/SNHG20/FOXK1 axis plays an important role in regulating vasculogenic mimicry formation of glioma, which might provide new targets of glioma therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1073-7) contains supplementary material, which is available to authorized users.

lncRNA small nucleolar RNA host gene 20 predicts poor prognosis in glioma and promotes cell proliferation by silencing P21

Background

In multiple cancers, long non-coding RNA small nucleolar RNA host gene 20 (lncRNA SNHG20) is generally dysregulated. In the present study, both the biological role and clinicopathological value of lncRNA SNHG20 in glioma are explored.

Methods

Real-time PCR was employed to determine lncRNA SNHG20 expression in glioma patients. The prognostic role of expression of lncRNA SNHG20 was evaluated in a retrospective cohort study. In addition, the association between lncRNA SNHG20 expression and the clinicopathological features of glioma patients, such as tumor recurrence, survival status, follow-up time, WHO grade, resection extent, tumor location, Karnofsky performance scale score, cystic change, tumor size, gender and age, was discussed. By constructing and transfecting siRNAs that targeted lncRNA SNHG20 into the glioma U87 cells, the effects of lncRNA SNHG20 on the proliferation and cell cycle of U87 cells were assessed through cell counting kit-8, colony formation and cell cycle assays, respectively. In addition, Western blot and real-time PCR measured the expression levels of P21 and CCNA1 in U87 cells after being transfected with SNHG20 siRNA.

Results

Our results suggested the high expression of lncRNA SNHG20 in human glioma tissues compared with normal brain tissues, which was related to recurrence-free survival and poor overall survival in glioma patients. According to the existing retrospective cohort study, high lncRNA SNHG20 expression was associated with tumor size, extent of resection, WHO grade, follow-up time, survival status and recurrence. Besides, knocking down the expression of lncRNA SNHG20 could inhibit the proliferation and colony formation abilities of glioma U87 cells through cell cycle arrest. Consequently, the expression of CCNA1 was inhibited, and the expression of P21 was up-regulated in U87 cells.

Conclusion

A high lncRNA SNHG20 expression level predicts the poor prognosis for glioma patients. Moreover, lncRNA SNHG20 can promote glioma proliferation through silencing P21 and thus lncRNA SNHG20 is an independent potential prognostic biomarker for glioma patients.

SNHG20 serves as a predictor for prognosis and promotes cell growth in oral squamous cell carcinoma

Accumulating evidence indicates that long non-coding RNAs (lncRNAs) serve important roles in various tumor types, including colorectal cancer and gastric cancer. The present study aimed to investigate the contribution of the lncRNA small nucleolar RNA host gene 20 (SNHG20) in oral squamous cell carcinoma (OSCC) progression. It was demonstrated that SNHG20 expression was significantly increased in OSCC tissue specimens, compared with in adjacent non-tumor tissue specimens. The increased SNHG20 expression in OSCC tissue specimens was associated with tumor differentiation and Tumor-Node-Metastasis stage. Kaplan-Meier analysis and log-rank tests indicated that Higher SNHG20 expression predicted a poor overall survival (OS) rate in patients with OSCC. Multivariate Cox proportional hazards regression analysis demonstrated that increased SNHG20 expression was an independent predictor for the OS of patients with OSCC. Knockdown of SNHG20 expression in OSCC cells suppressed proliferation. The cell proliferation-associated proteins proliferating cell nuclear antigen and Ki67 expression levels were reduced when SNHG20 was knocked down in OSCC cells; thus, the results indicated that SHNG20 may serve as a predictor and potential target for OSCC treatment.

Long non-coding RNA SNHG20 promotes the tumorigenesis of oral squamous cell carcinoma via targeting miR-197/LIN28 axis

Long non‐coding RNA (lncRNA) has been verified to participate in the tumour regulation, including oral squamous cell carcinoma (OSCC). Nevertheless, the role of lncRNA SNHG20 on OSCC still remains elusive. Here, we investigate the physiopathologic functions of lncRNA SNHG20 in OSCC tumorigenesis and explore its potential mechanism. LncRNA SNHG20 was up‐regulated in OSCC tissue compared with adjacent non‐tumour tissue. Meanwhile, SNHG20 was overexpressed in cancer stem‐like cells. In vitro and in vivo, loss‐of‐function experiments showed that lncRNA SNHG20 knockdown inhibited proliferative ability, mammosphere‐forming ability, ALDH1 expression, stem factors (LIN28, Nanog, Oct4, SOX2) and tumour growth. Bioinformatics and luciferase reporter assay revealed that miR‐197 targeted the 3′‐untranslated regions of SNHG20 and LIN28 by complementary binding. Validation experiments confirmed the associated functions of SNHG20/miR‐197/LIN28 axis on OSCC proliferation and stemness. In summary, our results reveal the important function of SNHG20/miR‐197/LIN28 axis in the oncogenesis and stemness of OSCC, suggesting the vital role of SNHG20 in OSCC tumorigenesis.

Role of lncRNA and EZH2 Interaction/Regulatory Network in Lung Cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts and longer than 200 nucleotides. LncRNAs have been demonstrated to modulate gene expression at transcriptional, post-transcriptional, as well as epigenetic levels in lung cancer. Interestingly, compelling studies have revealed that lncRNAs participated in the EZH2 oncogenic regulatory network. EZH2 plays an important role in the initiation, progression and metastasis of cancer. On one hand, lncRNAs can directly bind to EZH2, recruit EZH2 to the promoter region of genes and repress their expression. On the other hand, lncRNAs can also serve as EZH2 effectors or regulators. In this review, we summarized the types of lncRNA-EZH2 interaction and regulatory network identified till date and discussed their influence on lung cancer. Better understanding regarding the interaction and regulatory network will provide new insights on lncRNA- or EZH2-based therapeutic development in lung cancer.

Long non-coding RNA SNHG20 promotes nasopharyngeal carcinoma cell migration and invasion by upregulating TGF-β1

Small nucleolar RNA host gene 20 (SNHG20) has been reported to serve roles in several types of malignancies, while its role in nasopharyngeal carcinoma remains unknown. In the present study, tumor tissues and adjacent healthy tissues of patient with nasopharyngeal carcinoma, as well as blood samples from patients with nasopharyngeal carcinoma and heathy controls were collected, and expression levels of SNHG20 were detected by reverse transcription-quantitative polymerase chain reaction. Receiver operating characteristic curve and survival curve analyses were performed to evaluate the diagnostic and prognostic values of SNHG20 expression for nasopharyngeal carcinoma, respectively. Associations between serum expression levels of SNHG20 and clinical data of patients with nasopharyngeal carcinoma were analyzed using χ² test. A SNHG20 expression vector was constructed and transfected into nasopharyngeal carcinoma cells, and cell migration and invasion were detected by Transwell assays. Expression of transforming growth factor-β1 (TGF-β1) was detected by western blotting. Results indicated that the expression level of SNHG20 increased in cancer tissues compared with healthy tissues of patients with nasopharyngeal carcinoma. Serum level of SNHG20 increased in patients with nasopharyngeal carcinoma compared with healthy controls. Significant association was identified between serum levels of SNHG20 and distant tumor metastasis. Serum SNHG20 could serve as a potential diagnostic and prognostic marker for nasopharyngeal carcinoma. Overexpression of SNHG20 promoted nasopharyngeal carcinoma cell migration and invasion, and promoted the expression of TGF-β1. TGF-β1 inhibitor reduced the effects of SNHG20 overexpression on nasopharyngeal carcinoma cell migration and invasion, and exhibited no significant effect on SNHG20 expression. Therefore, the results of the present study indicated that lncRNA SNHG20 could promote the migration and invasion of nasopharyngeal carcinoma cells by upregulating TGF-β1.