Downregulation of long non-coding RNAs JPX and XIST is associated with the prognosis of hepatocellular carcinoma

Emerging role of circulating cell-free RNA as a non-invasive biomarker for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a severe neoplastic disease associated with high morbidity and mortality rates. HCC is often detected at advanced stages leading to ineffective curative treatments. Recently, liquid biopsy has emerged as a non-invasive method to identify highly specific HCC biomarkers in bodily fluids such as blood, serum, urine, and saliva. Circulating cell-free nucleic acids (cfNAs), particularly cell-free DNA (cfDNA) and cell-free RNA (cfRNA), have become promising candidates for biomarkers in liquid biopsy applications. While cfDNA presented significant challenges, researchers have turned their attention to cfRNA, which can be efficiently identified through various methods and is considered a potential biomarker for cancer diagnosis and prognosis. This review primarily focuses on studies related to detecting various cfRNA in body fluids as biomarkers. The aim is to provide a summary of available information to assist researchers in their investigations and the development of new diagnostic and prognostic tools.

Prognostic signature analysis and survival prediction of esophageal cancer based on N6-methyladenosine associated lncRNAs

Esophageal cancer (ESCA) has a bad prognosis. Long non-coding RNA (lncRNA) impacts on cell proliferation. However, the prognosis function of N6-methyladenosine (m6A)-associated lncRNAs (m6A-lncRNAs) in ESCA remains unknown. Univariate Cox analysis was applied to investigate prognosis related m6A-lncRNAs, based on which the samples were clustered. Wilcoxon rank and Chi-square tests were adopted to compare the clinical traits, survival, pathway activity and immune infiltration in different clusters where overall survival, clinical traits (N stage), tumor-invasive immune cells and pathway activity were found significantly different. Through least absolute shrinkage and selection operator and proportional hazard (Lasso-Cox) model, five m6A-lncRNAs were selected to construct the prognostic signature (m6A-lncSig) and risk score. To investigate the link between risk score and clinical traits or immunological microenvironments, Chi-square test and Spearman correlation analysis were utilized. Risk score was found connected with N stage, tumor stage, different clusters, macrophages M2, B cells naive and T cells CD4 memory resting. Risk score and tumor stage were found as independent prognostic variables. And the constructed nomogram model had high accuracy in predicting prognosis. The obtained m6A-lncSig could be taken as potential prognostic biomarker for ESCA patients. This study offers a theoretical foundation for clinical diagnosis and prognosis of ESCA.

Harnessing the supremacy of MEG3 LncRNA to defeat gastrointestinal malignancies

Evidence suggests that long non-coding RNAs (lncRNAs) play a pivotal role in the carcinogenesis and progression of various human malignancies including gastrointestinal malignancies. This comprehensive review reports the functions and mechanisms of the lncRNA maternally expressed gene 3 (MEG3) involved in gastrointestinal malignancies. It summarizes its roles in mediating the regulation of cellular proliferation, apoptosis, migration, invasiveness, epithelial-to-mesenchymal transition, and drug resistance in several gastrointestinal cancers such as colorectal cancer, gall bladder cancer, pancreatic cancer, gastric cancer, esophageal cancer, cholangiocarcinoma, gastrointestinal stromal tumors and most importantly, hepatocellular carcinoma. In addition, the authors briefly highlight its implicated mechanistic role and interactions with different non-coding RNAs and oncogenic signaling cascades. This review presents the rationale for developing non coding RNA-based anticancer therapy via harnessing the power of MEG3 in gastrointestinal malignancies.

Combinatorial Gene Expression Profiling of Serum HULC, HOTAIR, and UCA1 lncRNAs to Differentiate Hepatocellular Carcinoma from Liver Diseases: A Systematic Review and Meta-Analysis

Hepatocellular carcinoma (HCC) presents a significant global health challenge due to limited early detection methods, primarily relying on conventional approaches like imaging and alpha-fetoprotein (AFP). Although non-coding RNAs (ncRNAs) show promise as potential biomarkers in HCC, their true utility remains uncertain. We conducted a comprehensive review of 76 articles, analyzing 88 circulating lncRNAs in 6426 HCC patients. However, the lack of a standardized workflow protocol has hampered holistic comparisons across the literature. Consequently, we herein confined our meta-analysis to only a subset of these lncRNAs. The combined analysis of serum highly upregulated in liver cancer (HULC) gene expression with homeobox transcript antisense intergenic RNA (HOTAIR) and urothelial carcinoma-associated 1 (UCA1) demonstrated markedly enhanced sensitivity and specificity in diagnostic capability compared to traditional biomarkers or other ncRNAs. These findings could have substantial implications for the early diagnosis and tailored treatment of HCC.

Gender dimorphism in hepatocarcinogenesis-DNA methylation modification regulated X-chromosome inactivation escape molecule XIST

BACKGROUND

Sex disparities constitute a significant issue in hepatocellular carcinoma (HCC). However, the mechanism of gender dimorphism in HCC is still not completely understood.

METHODS

5-Hydroxymethylcytosine (5hmC)-Seal technology was utilised to detect the global 5hmC levels from four female and four male HCC samples. Methylation of XIST was detected by Sequenom MassARRAY methylation profiling between HCC tissues (T) and adjacent normal liver tissues (L). The role of Tet methylcytosine dioxygenase 2 (TET2) was investigated using diethylnitrosamine (DEN)-administered Tet2-/- female mice, which regulated XIST in hepatocarcinogenesis. All statistical analyses were carried out by GraphPad Prism 9.0 and SPSS version 19.0 software.

RESULTS

The results demonstrated that the numbers of 5hmC reads in the first exon of XIST from female HCC tissues (T) were remarkably lower than that in female adjacent normal liver tissues (L). Correspondingly, DNA methylation level of XIST first exon region was significantly increased in female T than in L. By contrast, no significant change was observed in male HCC patients. Compared to L, the expression of XIST in T was also significantly downregulated. Female patients with higher XIST in HCC had a higher overall survival (OS) and more extended recurrence-free survival (RFS). Moreover, TET2 can interact with YY1 binding to the promoter region of XIST and maintain the hypomethylation state of XIST. In addition, DEN-administered Tet2-/- mice developed more tumours than controls in female mice.

CONCLUSIONS

Our study provided that YY1 and TET2 could interact to form protein complexes binding to the promoter region of XIST, regulating the methylation level of XIST and then affecting the expression of XIST. This research will provide a new clue for studying sex disparities in hepatocarcinogenesis.

HIGHLIGHTS

XIST was significantly downregulated in HCC tissues and had gender disparity. Methylation levels in the XIST first exon were higher in female HCC tissues, but no significant change in male HCC patients. The TET2-YY1 complex regulate XIST expression in female hepatocytes. Other ways regulate XIST expression in male hepatocytes.

Emerging role of long non-coding RNA JPX in malignant processes and potential applications in cancers

ABSTRACT

Long non-coding RNAs (lncRNAs) reportedly function as important modulators of gene regulation and malignant processes in the development of human cancers. The lncRNA JPX is a novel molecular switch for X chromosome inactivation and differentially expressed JPX has exhibited certain clinical correlations in several cancers. Notably, JPX participates in cancer growth, metastasis, and chemoresistance, by acting as a competing endogenous RNA for microRNA, interacting with proteins, and regulating some specific signaling pathways. Moreover, JPX may serve as a potential biomarker and therapeutic target for the diagnosis, prognosis, and treatment of cancer. The present article summarizes our current understanding of the structure, expression, and function of JPX in malignant cancer processes and discusses its molecular mechanisms and potential applications in cancer biology and medicine.

The role of lncRNA just proximal to XIST (JPX) in human disease phenotypes and RNA methylation: The novel biomarker and therapeutic target potential

Increasing evidence suggests that long non-coding RNAs (lncRNAs) are closely related to the initialization and development of human diseases. lncRNA just proximal to XIST (JPX), as a newly identified lncRNA, has been reported to be aberrantly expressed and associated with pathophysiological traits in numerous diseases, particularly cancers. More importantly, JPX has been proven to play important roles in various biological functions, including cell proliferation, migration, invasion, apoptosis, chemoresistance, and differentiation. In addition, we discuss the diverse molecular mechanisms and correlation with RNA methylation of JPX in several cancers. In this Review, we summarize current studies on JPX's roles in diseases and its potential application as a biomarker for both diagnoses and prognoses and a therapeutic target in human diseases.

Circulating Non-Coding RNAs as Potential Diagnostic Biomarkers in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is currently the second leading cause of cancer-related deaths worldwide, with high morbidity and mortality. The clinical diagnosis of HCC mainly depends on imaging technology, such as ultrasound and computed tomography, and serum biomarkers, such as alpha-fetoprotein (AFP). However, HCC is still hard to diagnose at an early stage due to the low sensitivity of the above mentioned traditional methods. Typically, HCC is diagnosed at an advanced stage when limited treatment options are available. It is urgent to identify effective biomarkers for the early diagnosis of HCC. Increasing evidence uncovered ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), could be used in HCC diagnosis. The aim of this review is to summarize our understanding of circulating miRNAs, lncRNAs and circRNAs as fluid-based non-invasive biomarkers, and aiming at providing new insights into the diagnosis of HCC.

LncRNA JPX Promotes Esophageal Squamous Cell Carcinoma Progression by Targeting miR-516b-5p/VEGFA Axis

Simple Summary

LncRNA JPX acts as an oncogenic regulator in various types of cancer. Here, we present insights into the mechanistic evidence for the function of JPX in ESCC progression. To clarify the potential role of JPX in ESCC, JPX was upregulated or downregulated in ESCC cells, and in a xenograft model. We showed that JPX promoted ESCC cell proliferation, migration, and invasion via the miR-516b-5p/VEGFA pathway. Our study revealed the importance of JPX as a promising biomarker for ESCC diagnosis and therapeutic target for ESCC in clinic.

Abstract

Long non-coding RNAs (lncRNAs) are reported act as important regulators in various types of cancer. LncRNA JPX was identified as an oncogenic regulator in lung cancer. However, the function of JPX in the progression of esophageal squamous cell carcinoma (ESCC) remains unclear. In the present study, we found JPX was highly expressed in esophageal tissue from ESCC patients. Functional assays demonstrated that JPX promoted ESCC cell proliferation, migration, and invasion in vitro, and accelerated tumor growth in vivo. Mechanistically, the results showed that JPX functioned as a sponge of miR-516b-5p, which targeted vascular endothelial growth factor A (VEGFA) in ESCC cells. Interactions between miR-516b-5p and JPX or VEGFA were confirmed by luciferase reporter assays. Inhibition of JPX significantly attenuated the cell growth and mobility ability of ESCC cells in vitro. In addition, overexpression of miR-516b-5p abrogated JPX-enhanced proliferation, migration, invasion, and angiogenesis of ESCC cells. Our study demonstrated that JPX played an important role in promoting ESCC progression via the miR-516b-5p/VEGFA pathway, which might serve as a promising novel diagnostic biomarker and therapeutic target for ESCC in clinic.

Long non-coding RNA X-inactive specific transcript suppresses the progression of hepatocellular carcinoma through microRNA-221-3p-targeted regulation of O6-methylguanine-DNA methyltransferase

MicroRNA-221-3p (miR-221-3p) is an important regulator involved in the progression and prognosis of various cancers. In this study, we aimed to investigate the diagnostic and prognostic value of miR-221-3p expression along with long non-coding RNA X–inactive specific transcript (XIST), which was identified as its upstream regulator in hepatocellular carcinoma (HCC) by bioinformatics analysis, and further validated by RNA immunoprecipitation (RIP) and dual-luciferase reporter assays. Their expression was measured in tumor tissues and corresponding non-tumor tissues by quantitative real-time PCR (qRT-PCR), which revealed that XIST was weakly expressed in HCC cells and tumors, while miR-221-3p was overexpressed. Complete knockdown of XIST enhanced HCC cell proliferation and migration and inhibited apoptosis, as observed by MTT, transwell, and flow cytometry experiments, respectively. Animal studies validated that XIST knockdown induces tumor growth in vivo. In contrast, upregulation of XIST in HCC cells suppressed their proliferation and migration, stimulated apoptosis, and retarded the growth rate of tumors in vivo. These effects were partially reversed by upregulating miR-221-3p expression. Furthermore, we demonstrated that O⁶-methylguanine-DNA methyltransferase (MGMT) is a downstream target of miR-221-3p. It was weakly expressed in HCC cells and tumors and showed a negative correlation with miR-221-3p. Forced MGMT expression repressed proliferation and migration and enhanced apoptosis in HCC cells. Nevertheless, these anti-tumor effects induced by MGMT overexpression could be abolished by miR-221-3p upregulation. Collectively, our findings reveal that XIST blocks the development of HCC through miR-221-3p-targeted regulation of MGMT. This reveals a new mechanism involved in the development of HCC.

Diagnostic value of RNA for hepatocellular carcinoma: a network meta-analysis

Aim: The aim of this study was to evaluate the capacity of RNA in the diagnosis of hepatocellular carcinoma (HCC). Methods: A systematic review was conducted from PubMed, Cochrane Library, EMBASE and Web of Science databases via well-designed retrieval strategy. Subsequently, the network meta-analysis was performed by the STATA software. Results: Through statistical analysis, the three hypotheses of the network meta-analysis were established. In view of these hypotheses, the diagnostic efficacy of the three markers in HCC (HCC vs healthy people) may be consistent, and the cumulative ranking results showed such a trend: circular RNA >long noncoding RNA >microRNA. Conclusion: Circular RNA may be most effective for diagnosing HCC across the three types of RNA.

Anticancer effects of melatonin via regulating lncRNA JPX-Wnt/β-catenin signalling pathway in human osteosarcoma cells

Osteosarcoma (OS) is a type of malignant primary bone cancer, which is highly aggressive and occurs more commonly in children and adolescents. Thus, novel potential drugs and therapeutic methods are urgently needed. In the present study, we aimed to elucidate the effects and mechanism of melatonin on OS cells to provide a potential treatment strategy for OS. The cell survival rate, cell viability, proliferation, migration, invasion and metastasis were examined by trypan blue assay, MTT, colony formation, wound healing, transwell invasion and attachment/detachment assay, respectively. The expression of relevant lncRNAs in OS cells was determined by real-time qPCR analysis. The functional roles of lncRNA JPX in OS cells were further examined by gain and loss of function assays. The protein expression was measured by western blot assay. Melatonin inhibited the cell viability, proliferation, migration, invasion and metastasis of OS cells (Saos-2, MG63 and U2OS) in a dose-dependent manner. Melatonin treatment significantly downregulated the expression of lncRNA JPX in Saos-2, MG63 and U2OS cells. Overexpression of lncRNA JPX into OS cell lines elevated the cell viability and proliferation, which was accompanied by the increased metastasis. We also found that melatonin inhibited the OS progression by suppressing the expression of lncRNA JPX via regulating the Wnt/β-catenin pathway. Our results suggested that melatonin inhibited the biological functions of OS cells by repressing the expression of lncRNA JPX through regulating the Wnt/β-catenin signalling pathway, which indicated that melatonin might be applied as a potentially useful and effective natural agent in the treatment of OS.

JPX and LINC00641 ncRNAs expression in prostate tissue: a case-control study

Background and purpose

Prostate cancer (PC) is the second most prevalent cancer in men. Prostate-specific antigen (PSA) is the main biomarker for screening PC. An increase in PSA could lead to false-positive results. Thus, more appropriate markers should be investigated. In the present study, JPX and LINC00641 expression levels were measured in tumoral prostate tissue compared with the non-tumor tissue.

Experimental approach

43 pairs of prostate tumoral and non-tumor tissue were prepared. The expression levels of JPX and LINC00641 were investigated by RT-qPCR.

Findings/Results

Significant upregulation of LINC00641 (2.47 ± 0.5 vs 1.41 ± 0.2) and downregulation of JPX (1.42 ± 0.6 vs 2.83 ± 1.0) were observed in PC tissues compared with the normal tissues (their adjacent non-tumoral tissues).

Conclusion and implications

Dysregulation of JPX and LINC00641 in PC patients could be used in the future as a prognostic biomarker in PC.

The Diagnostic Performance of lncRNAs from Blood Specimens in Patients with Hepatocellular Carcinoma: A Meta-Analysis

OBJECTIVE

Long noncoding RNAs (lncRNAs) are widely involved in the carcinogenesis and development of cancers. We conducted a meta-analysis to evaluate the diagnostic performance of lncRNAs in hepatocellular carcinoma (HCC).

METHODS

After the inclusion and exclusion process, relevant information was extracted. Heterogeneity between studies was evaluated, and data synthesis was conducted by employing a bivariate random-effects model.

RESULTS

In total, 20 eligible studies were enrolled. The pooled sensitivity and specificity were 0.86 (95% confidence interval [CI], 0.80-0.90) and 0.88 (95% CI, 0.82-0.92), respectively. The pooled positive likelihood ratio, pooled negative likelihood ratio, and pooled diagnostic odds ratio were 7.1 (95% CI, 4.9-10.2), 0.16 (95% CI, 0.11-0.23), and 44 (95% CI, 25-79), respectively. The results of the linear regression method and visual inspection of the Deeks funnel plot did not indicate significant publication bias.

CONCLUSION

Our meta-analysis suggested that lncRNAs have high diagnostic performance for HCC and have the potential for clinical application.

X-Inactive-Specific Transcript: Review of Its Functions in the Carcinogenesis

X-inactive-specific transcript (XIST) is one of the firstly discovered long non-coding RNAs with prominent roles in the process of X inactivation. Moreover, this transcript contributes in the carcinogenic process in different tissues. In addition to interacting with chromatin modifying molecules, XIST can be served as a molecular sponge for miRNAs to modulate expression of miRNA targets. Most of the studies have indicated an oncogenic role for XIST. However, in prostate cancer, a single study has indicated a tumor suppressor role for this lncRNA. Similar result has been reported for XIST in oral squamous cell carcinoma. In hepatocellular carcinoma, breast cancer, ovarian cancer, osteosarcoma, and renal cell carcinoma, different studies have reported inconsistent results. In the present manuscript, we review function of XIST in the carcinogenesis.

Biological Function of Long Non-coding RNA (LncRNA) Xist

Long non-coding RNAs (lncRNAs) regulate gene expression in a variety of ways at epigenetic, chromatin remodeling, transcriptional, and translational levels. Accumulating evidence suggests that lncRNA X-inactive specific transcript (lncRNA Xist) serves as an important regulator of cell growth and development. Despites its original roles in X-chromosome dosage compensation, lncRNA Xist also participates in the development of tumor and other human diseases by functioning as a competing endogenous RNA (ceRNA). In this review, we comprehensively summarized recent progress in understanding the cellular functions of lncRNA Xist in mammalian cells and discussed current knowledge regarding the ceRNA network of lncRNA Xist in various diseases. Long non-coding RNAs (lncRNAs) are transcripts that are more than 200 nt in length and without an apparent protein-coding capacity (Furlan and Rougeulle, 2016; Maduro et al., 2016). These RNAs are believed to be transcribed by the approximately 98-99% non-coding regions of the human genome (Derrien et al., 2012; Fu, 2014; Montalbano et al., 2017; Slack and Chinnaiyan, 2019), as well as a large variety of genomic regions, such as exonic, tronic, and intergenic regions. Hence, lncRNAs are also divided into eight categories: Intergenic lncRNAs, Intronic lncRNAs, Enhancer lncRNAs, Promoter lncRNAs, Natural antisense/sense lncRNAs, Small nucleolar RNA-ended lncRNAs (sno-lncRNAs), Bidirectional lncRNAs, and non-poly(A) lncRNAs (Ma et al., 2013; Devaux et al., 2015; St Laurent et al., 2015; Chen, 2016; Quinn and Chang, 2016; Richard and Eichhorn, 2018; Connerty et al., 2020). A range of evidence has suggested that lncRNAs function as key regulators in crucial cellular functions, including proliferation, differentiation, apoptosis, migration, and invasion, by regulating the expression level of target genes via epigenomic, transcriptional, or post-transcriptional approaches (Cao et al., 2018). Moreover, lncRNAs detected in body fluids were also believed to serve as potential biomarkers for the diagnosis, prognosis, and monitoring of disease progression, and act as novel and potential drug targets for therapeutic exploitation in human disease (Jiang W. et al., 2018; Zhou et al., 2019a). Long non-coding RNA X-inactive specific transcript (lncRNA Xist) are a set of 15,000-20,000 nt sequences localized in the X chromosome inactivation center (XIC) of chromosome Xq13.2 (Brown et al., 1992; Debrand et al., 1998; Kay, 1998; Lee et al., 2013; da Rocha and Heard, 2017; Yang Z. et al., 2018; Brockdorff, 2019). Previous studies have indicated that lncRNA Xist regulate X chromosome inactivation (XCI), resulting in the inheritable silencing of one of the X-chromosomes during female cell development. Also, it serves a vital regulatory function in the whole spectrum of human disease (notably cancer) and can be used as a novel diagnostic and prognostic biomarker and as a potential therapeutic target for human disease in the clinic (Liu et al., 2018b; Deng et al., 2019; Dinescu et al., 2019; Mutzel and Schulz, 2020; Patrat et al., 2020; Wang et al., 2020a). In particular, lncRNA Xist have been demonstrated to be involved in the development of multiple types of tumors including brain tumor, Leukemia, lung cancer, breast cancer, and liver cancer, with the prominent examples outlined in Table 1. It was also believed that lncRNA Xist (Chaligne and Heard, 2014; Yang Z. et al., 2018) contributed to other diseases, such as pulmonary fibrosis, inflammation, neuropathic pain, cardiomyocyte hypertrophy, and osteoarthritis chondrocytes, and more specific details can be found in Table 2. This review summarizes the current knowledge on the regulatory mechanisms of lncRNA Xist on both chromosome dosage compensation and pathogenesis (especially cancer) processes, with a focus on the regulatory network of lncRNA Xist in human disease.

The Impact of Long Non-Coding RNAs in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the utmost deadly human malignancies. This type of cancer has been associated with several environmental, viral, and lifestyle risk factors. Among the epigenetic factors which contribute in the pathogenesis of HCC is dysregulation of long non-coding RNAs (lncRNAs). These transcripts modulate expression of several tumor suppressor genes and oncogenes and alter the activity of cancer-related signaling axes. Several lncRNAs such as NEAT1, MALAT1, ANRIL, and SNHG1 have been up-regulated in HCC samples. On the other hand, a number of so-called tumor suppressor lncRNAs namely CASS2 and MEG3 are down-regulated in HCC. The interaction between lncRNAs and miRNAs regulate expression of a number of mRNA coding genes which are involved in the pathogenesis of HCC. H19/miR-15b/CDC42, H19/miR-326/TWIST1, NEAT1/miR-485/STAT3, MALAT1/miR-124-3p/Slug, MALAT1/miR-195/EGFR, MALAT1/miR-22/SNAI1, and ANRIL/miR-144/PBX3 axes are among functional axes in the pathobiology of HCC. Some genetic polymorphisms within non-coding regions of the genome have been associated with risk of HCC in certain populations. In the current paper, we describe the recent finding about the impact of lncRNAs in HCC.

LncRNA XIST upregulates TRIM25 via negatively regulating miR-192 in hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

Long non-coding RNA (lncRNA) XIST has been implicated in the progression of a variety of tumor diseases. The purpose of this study was to explore the molecular role of lncRNA XIST in human hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

METHODS

The expression levels of lncRNA XIST, miR-192 and TRIM25 in HBV-related HCC tissues and HepG2.2.15 cells were detected by qRT-PCR. Biological information and luciferin gene reporter assay were performed to detect the interaction among lncRNA XIST, miR-192 and TRIM25. CCk-8 assay, wound healing assay and colony formation assay were conducted to detect the proliferation and migration ability of HepG2.2.15 cells.

RESULTS

qRT-PCR results showed that the expression levels of lncRNA XIST were remarkably increased in HBV-related HCC tissues and HepG2.2.15 cells. In addition, miR-192 was a direct target gene of lncRNA XIST, and the expression of miR-192 and lncRNA XIST were negatively correlated. Moreover, overexpression of miR-192 observably inhibited the proliferation and migration of HCC cells, while overexpression of lncRNA XIST showed an opposite effect. Furthermore, TRIM25 was a direct target of miR-192, and lncRNA XIST could up-regulate the expression of TRIM25 by targeting miR-192.

CONCLUSION

LncRNA XIST could up-regulate the expression of TRIM25 by targeting and binding to miR-192, thus accelerating the occurrence and development of HCC.

Peripheral Blood Genetic Biomarkers for the Early Diagnosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and has high mortality. Biomarkers related to HCC, such as alpha-fetoprotein, and imaging technology, such as ultrasound and computed tomography, have been used to screen and monitor HCC, but HCC is still difficult to diagnose effectively in the early stage due to the low sensitivity of the above mentioned traditional methods. There is an urgent need for noninvasive biomarkers to facilitate the screening and early diagnosis of HCC. With the advancement of next-generation sequencing, genetic biomarkers are becoming the core of cancer diagnosis. Genetic biomarkers such as peripheral blood circulating tumor DNA, microRNAs, long noncoding RNAs, circular RNAs, and exosomes have become the focus of early HCC diagnostics. HCC genetic biomarkers have been implemented in clinical practice. In this review, we describe the available literature on peripheral blood genetic biomarkers in the diagnosis of early HCC.

Identification of a long non-coding RNA regulator of liver carcinoma cell survival

Genomic studies have significantly improved our understanding of hepatocellular carcinoma (HCC) biology and have led to the discovery of multiple protein-coding genes driving hepatocarcinogenesis. In addition, these studies have identified thousands of new non-coding transcripts deregulated in HCC. We hypothesize that some of these transcripts may be involved in disease progression. Long non-coding RNAs are a large class of non-coding transcripts which participate in the regulation of virtually all cellular functions. However, a majority of lncRNAs remain dramatically understudied. Here, we applied a pooled shRNA-based screen to identify lncRNAs essential for HCC cell survival. We validated our screening results using RNAi, CRISPRi, and antisense oligonucleotides. We found a lncRNA, termed ASTILCS, that is critical for HCC cell growth and is overexpressed in tumors from HCC patients. We demonstrated that HCC cell death upon ASTILCS knockdown is associated with apoptosis induction and downregulation of a neighboring gene, protein tyrosine kinase 2 (PTK2), a crucial protein for HCC cell survival. Taken together, our study describes a new, non-coding RNA regulator of HCC.

Circulating Long and Circular Noncoding RNA as Non-Invasive Diagnostic Tools of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide, partially due to late diagnosis of the disease. Growing evidence in the field of biomarker discovery has shown the promising use of nucleic acid in the early detection of many cancers, including HCC. Here, we review data on how various long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) could be used as a diagnostic tool for HCC being differentially expressed in HCC compared to non-HCC patients. These non-coding RNAs (ncRNAs) showed high stability in the blood being present as free-circulating molecules or encapsulated into exosomes. This review reports some recent evidence on the use of lncRNAs and circRNAs as possible diagnostic biomarkers for HCC. Further, their pathophysiological mechanism in liver carcinogenesis was also described, elucidating the complex regulatory networks making these ncRNAs of particular relevance for the study of liver malignancy cancer.

Diagnostic value of circulating lncRNAs as biomarkers of digestive system cancers: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis aims to explore the diagnostic value and accuracy of circulating lncRNAs as biomarkers of digestive system tumors.

METHODS

PubMed, Embase, Cochrane Library, and Web of science were searched for relevant articles that were published before April 2019, and a meta-analysis was conducted.

RESULTS

52 studies with 63 lncRNAs were discussed in the meta-analysis. The pooled sensitivity and specificity of diagnosis were 0.80 (95% CI: 0.79-0.81) and 0.76 (95% CI: 0.75-0.77), respectively. The pooled DOR (the diagnostic odds ratio) was 15.63 (95% CI: 12.77-19.12), and the overall AUC (the area under the curve) was 0.87. Besides, subgroup analyzes showed that the DOR and AUC of large sample sizes (>80), multiple lncRNAs, serum-based lncRNAs, and downregulation group were superior to those of small sample sizes (≤80), single lncRNA, plasma-based lncRNAs, and upregulation group, respectively. The current data also highlight that the diagnostic accuracy of circulating lncRNAs in the case of colorectal cancer was higher than gastric cancer, hepatocellular carcinoma, esophageal carcinoma, and pancreatic cancer. And there is no difference in the perspective of geographical regions.

CONCLUSION

The circulating lncRNAs have high diagnostic value and accuracy in digestive system cancers and may serve as potential biomarkers.

LncRNA JPX promotes cervical cancer progression by modulating miR-25-3p/SOX4 axis

Background

The long noncoding RNA (lncRNA) JPX is a molecular switch for X-chromosome inactivation. Accumulating studies have shown that the aberrant expression and function of lncRNAs are involved in the occurrence and development of tumors. However, the functional importance and mechanism of the action of lncRNA JPX in cervical cancer (CC) remain unknown.

Method

In this study, qRT-PCR and western blotting were used to evaluate the mRNA or protein expression of JPX, miR-25-3p and SOX4 in CC tissues and cell lines. StarBase v2.0 database, luciferase reporter assay and RNA immunoprecipitation assay were used to explore the relationship between JPX and miR-25-3p. EdU assay, CCK-8 assay and transwell assay were utilized to evaluate the proliferation, migration and invasion of CC cells. The tumor xenograft assay in nude mice was performed to demonstrate the role of the JPX/miR-25-3p/SOX4 axis in CC.

Results

We found that JPX was markedly upregulated, whereas miR-25-3p was markedly downregulated in CC tissues and cell lines, and the expression of JPX was negatively correlated with miR-25-3p in CC tissues. Moreover, overexpression of JPX increased proliferation, migration and invasion of HeLa cells, whereas knockdown of JPX decreased proliferation, migration and invasion of HeLa cells. In contrast to JPX, overexpression of miR-25-3p decreased proliferation, migration and invasion of HeLa cells. In addition, knockdown of JPX was found to inhibit HeLa cell viability and tumor development via up-regulating the expression of miR-25-3p and inhibiting the expression of SOX4.

Conclusions

Our study demonstrates that JPX promotes cervical cancer progression through modulating the miR-25-3p/SOX4 axis, and may serve as a potential target for CC therapy.

Serum small extracellular vesicle-derived LINC00853 as a novel diagnostic marker for early hepatocellular carcinoma

This study aimed to identify novel long noncoding RNA (lncRNA) biomarkers for hepatocellular carcinoma (HCC) using publicly available tissue genomic datasets and validate their diagnostic utility for early-stage HCC. Differentially expressed lncRNAs between 371 HCC and 50 nontumor tissues were obtained from The Cancer Genome Atlas liver hepatocellular carcinoma (TCGA_LIHC) project. Subsequently, the expression of the serum- and extracellular vesicle (EV)-derived lncRNA was assessed in 10 patients with HCC and 10 healthy controls using RT-qPCR. The candidate lncRNAs were validated in 90 HCC and 92 non-HCC (29 healthy control, 28 chronic hepatitis, 35 liver cirrhosis) patients. The sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated for the candidate lncRNAs and the current HCC biomarker, alpha-fetoprotein (AFP). SFTA1P, HOTTIP, HAGLROS, LINC01419, HAGLR, CRNDE, and LINC00853 were markedly upregulated in HCC in TCGA_LIHC dataset. Among them, LINC00853 has not been reported in relation to HCC before. In patients with HCC, only expression of small EV-derived LINC00853 (EV-LINC00853) was increased. EV-LINC00853 showed excellent discriminatory ability in the diagnosis of all-stage HCC (AUC = 0.934, 95% confidence interval = 0.887-0.966). Moreover, using a 14-fold increase and 20 ng·mL^-1 as cutoffs for EV-LINC00853 expression and AFP level, respectively, EV-LINC00853 was found to have a sensitivity of 93.75% and specificity of 89.77%, while AFP showed only 9.38% sensitivity and 72.73% specificity for the diagnosis of early-stage HCC (mUICC stage I). EV-LINC00853 had a positivity of 97% and 67% in AFP-negative and AFP-positive early HCC, respectively. Serum EV-derived LINC00853 may be a novel potential diagnostic biomarker for early HCC, especially for AFP-negative HCC.

Long noncoding RNA SPRY4-IT1 promotes proliferation and metastasis of hepatocellular carcinoma via mediating TNF signaling pathway

Our previous studies have indicated that long noncoding RNA (lncRNA) SPRY4 intronic transcript 1 (SPRY4-IT1) was highly expressed in hepatocellular carcinoma (HCC). However, it still remained unclear how SPRY4-IT1 worked in tumorgenesis in HCC. In this study, we tested the overexpression of SPRY4-IT1 in HCC tissues and cells through a quantitative real-time polymerase chain reaction. Statistical analyses showed that the upregulation had an association with the tumor node metastasis stage, thrombin time, and alkaline phosphatase. Furthermore, SPRY4-IT1 could be involved in cell proliferation, metastasis, and the epithelial-to-mesenchymal transition (EMT) process in HCC in vitro and in vivo. RNA-sequencing and transcriptome analysis were carried out to explore the mechanism of SPRY4-IT1 in HCC. With SPRY4-IT1 being knocked down or overexpressed, the level of proteins in the tumor necrosis factor (TNF) signaling pathway changed. We detected the RNA binding protein heterogeneous nuclear ribonucleoprotein L (HNRNPL) as a SPRY4-IT1 interacting protein through RNA pull-down assay and liquid chromatography-mass spectrometry, then verified through RNA immunoprecipitation. Downregulation of HNRNPL induced the change of proteins observed on SPRY4-IT1 downregulation revealing the SPRY4-IT1: HNRNPL complex in the TNF signaling pathway and EMT process in HCC. In general, our experimental data and analysis demonstrated the role of SPRY4-IT1 in promoting progress and metastasis of HCC by the TNF signaling pathway.

Long non-coding RNA XIST expression as a prognostic factor in human cancers: A meta-analysis

A large number of literature has shown that high expression of X inactive-specific transcript (XIST) is associated with poor prognosis and metastasis of cancer in patients. However, most of this literature is limited by the small sample sizes and discrete outcomes. Therefore, a meta-analysis was performed to investigate the relation between XIST expression and tumor node metastasis (TNM) stage, lymph node metastasis, distant metastasis, and overall survival of cancer patients. We searched for literature in PubMed, Embase, and Web of Science. The pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the association of XIST expression with prognosis and clinicopathological characteristics of cancer patients. Finally, a total of 14 articles involving 1123 patients were included in this meta-analysis. The results suggested that high expression of XIST has a significant relationship with a relatively poor overall survival for patients with malignant tumors (HR 1.82; 95% CI 1.32, 2.52; P = 0.0003). Moreover, high expression of XIST was significantly associated with poor TNM stage (OR 3.64; 95% CI 2.62, 5.07; P < 0.0001), lymph node metastasis (OR 2.39; 95% CI 1.65, 3.46; P < 0.0001) and distant metastasis (OR 2.84; 95% CI 1.90, 4.23; P < 0.0001). In conclusion, high expression of lncRNA XIST may be a predictive factor of poor prognosis in human cancers.

Roles and Regulation of Long Noncoding RNAs in Hepatocellular Carcinoma

Next-generation sequencing has uncovered thousands of long noncoding RNAs (lncRNA). Many are reported to be aberrantly expressed in various cancers, including hepatocellular carcinoma (HCC), and play key roles in tumorigenesis. This review provides an in-depth discussion of the oncogenic mechanisms reported to be associated with deregulated HCC-associated lncRNAs. Transcriptional expression of lncRNAs in HCC is modulated through transcription factors, or epigenetically by aberrant histone acetylation or DNA methylation, and posttranscriptionally by lncRNA transcript stability modulated by miRNAs and RNA-binding proteins. Seventy-four deregulated lncRNAs have been identified in HCC, of which, 52 are upregulated. This review maps the oncogenic roles of these deregulated lncRNAs by integrating diverse datasets including clinicopathologic features, affected cancer phenotypes, associated miRNA and/or protein-interacting partners as well as modulated gene/protein expression. Notably, 63 deregulated lncRNAs are significantly associated with clinicopathologic features of HCC. Twenty-three deregulated lncRNAs associated with both tumor and metastatic clinical features were also tumorigenic and prometastatic in experimental models of HCC, and eight of these mapped to known cancer pathways. Fifty-two upregulated lncRNAs exhibit oncogenic properties and are associated with prominent hallmarks of cancer, whereas 22 downregulated lncRNAs have tumor-suppressive properties. Aberrantly expressed lncRNAs in HCC exert pleiotropic effects on miRNAs, mRNAs, and proteins. They affect multiple cancer phenotypes by altering miRNA and mRNA expression and stability, as well as through effects on protein expression, degradation, structure, or interactions with transcriptional regulators. Hence, these insights reveal novel lncRNAs as potential biomarkers and may enable the design of precision therapy for HCC.

Small Nucleolar RNA Host Gene 18 Acts as a Tumor Suppressor and a Diagnostic Indicator in Hepatocellular Carcinoma

BACKGROUND

Noncoding RNAs are crucial regulators acting as either tumor suppressor genes or oncogenes in human cancer progression. The aberrant expression of noncoding RNAs has been confirmed in different kinds of cancers. Hepatocellular carcinoma is one of the most common malignant tumors worldwide, characterized by insidious onset, great malignancy, and high rates of recurrence and metastasis. Due to lack of early predictive markers, numerous patients are diagnosed in the late stages. As therapeutic options for advanced patients are quite limited, great efforts have been made to screen patients at early stages. A previous study reported that small nucleolar RNA host gene 18 played crucial role in glioma. However, its functions and roles in hepatocellular carcinoma are unknown.

PURPOSE

To explore its functional role and diagnostic value in hepatocellular carcinoma, we investigated its expression level.

METHODS

We performed real-time quantitative polymerase chain reaction in tumor tissues and adjacent noncancerous tissues derived from patients with hepatocellular carcinoma as well as in plasma, including samples from the healthy control, patients with hepatitis B, cirrhosis, and hepatocellular carcinoma.

RESULTS

Small nucleolar RNA host gene 18 was downregulated in liver tissues compared to paired adjacent noncancerous tissues ( P < .0001). Meanwhile, plasma small nucleolar RNA host gene 18 showed a relatively high sensitivity and specificity (75.61% and 73.49%) for distinguishing patients with hepatocellular carcinoma whose α-fetoprotein levels were below 200 ng/mL from the healthy controls.

CONCLUSION

Our study suggested that small nucleolar RNA host gene 18 might act as a tumor suppressor gene in hepatocellular carcinoma and potentially a diagnostic indicator to distinguish hepatocellular carcinoma from the healthy control and cirrhosis.

Clinicopathological and prognostic significance of zinc finger antisense 1 overexpression in cancers: A meta-analysis

BACKGROUND

An increasing number of studies have recently highlighted the role of zinc finger antisense 1(ZFAS1) as a prognostic marker in cancers. However, these results remain controversial. Hence, a meta-analysis was conducted to further investigate the effects of ZFAS1 expression on clinicopathological features and survival outcomes.

METHOD

All eligible studies were searched from PubMed, Embase, Web of Science, and the Cochrane Library. All included articles evaluated the relationship between the expression levels of ZFAS1 and survival, or the range of pathological features in cancer patients. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were computed to evaluate the effect of ZFAS1 expression on overall survival (OS), relapse-free survival (RFS), and disease-free survival (DFS). The relationship between ZFAS1 expression and clinicopathological features was determined through pooled odds ratios (ORs) and 95% CIs.

RESULTS

In total 8 studies, which comprised of 820 patients, were qualified for analysis. Results revealed that the overexpression of ZFAS1 was significantly associated with poor OS (HR = 1.97, 95% CI: 1.53-2.54), worse RFS (HR = 1.95, 95% CI: 1.24-3.04) and worse DFS (HR = 2.35, 95% CI: 1.43-3.88) in cancers. Further subgroup analysis revealed that ZFAS1 overexpression was significantly correlated with poor OS in different cancer types, HR obtain methods and sample sizes. In addition, this meta-analysis revealed that the upregulated expression of ZFAS1 was significantly associated with lymph node metastasis, Tumor Node Metastasis (TNM) stage, and tumor size.

CONCLUSIONS

This meta-analysis revealed that the expression of ZFAS1 was associated with tumor prognosis. ZFAS1 could be used as a predictor for tumor progression in various cancers.

Upregulation of long noncoding RNA XIST is associated with poor prognosis in human cancers

Growing evidence from recent studies has shown that the X-inactive specific transcript (XIST), a well-known long noncoding RNA involved in early embryonic development, is aberrantly regulated in various human cancers. However, the prognostic value of XIST in cancers remains uncharacterized. In this study, we searched PubMed, Web of Science, and Embase to collect all relevant studies, and a meta-analysis was performed to explore the association of XIST expression with overall survival (OS) and clinicopathological parameters. We demonstrated that high XIST expression was associated with poor OS (hazard ratio = 1.76; 95% confidence intervals [CI], 1.56-1.98; p < 0.001). In addition, increased XIST expression was found to be associated with lymph node metastasis (odds ratio [OR] = 2.06; 95% CI, 1.46-1.90; p < 0.001), distant metastasis (OR = 2.93; 95% CI, 2.00-4.28; p < 0.001), tumor size (OR = 2.66; 95% CI, 1.86-3.81; p < 0.001), poor differentiation (OR = 1.45; 95% CI, 1.00-2.10; p = 0.049), and advanced tumor stage (OR = 3.35; 95% CI, 2.25-5.00; p < 0.001), but not with age (OR = 0.82; 95% CI, 0.59-1.15; p = 0.251) or gender (OR = 0.92; 95% CI, 0.70-1.19; p = 0.512). Our meta-analysis showed that XIST may be a useful common biomarker for predicting prognosis in patients with cancer.

Diagnostic Value of lncRNAs as Biomarker in Hepatocellular Carcinoma: An Updated Meta-Analysis

Some long noncoding RNAs (lncRNAs) display aberrantly high or low expression in hepatocellular carcinoma (HCC) and have the potential to serve as diagnostic biomarkers. Here, we accomplished a meta-analysis based on current studies to assess the diagnostic value of lncRNAs in HCC. Eligible literatures were systematically selected from PubMed, Web of Science, and Embase (up to January 20, 2018) according to defined inclusion and exclusion criteria. QUADAS scale was applied to the quality assessment of the included studies. Statistical analysis was performed through bivariate random-effects models based on R software. Publication bias was evaluated by funnel plot and Begg's and Egger's tests. 16 articles containing 2,268 cancer patients and 2,574 controls were selected for the final meta-analysis. Random effect model was used for the meta-analysis due to significant between-study heterogeneity. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were 0.87(0.838-0.897), 0.829(0.794-0.86), 23.085(20.575-25.901), 4.533(4.239-4.847), and 0.176(0.166-0.186), respectively. Summary receiver operating characteristic curve (SROC) was conducted to estimate the diagnostic accuracy of lncRNAs in HCC with the area under curve (AUC) of 0.915. Subgroups analysis showed that lncRNA profiling, sample size, specimen types, and ethnicity might be the sources of heterogeneity. No publication bias existed according to funnel plot symmetry and Begg's (P = 0.187) and Egger's (P = 0.477) tests. In conclusion, lncRNAs can serve as potential diagnostic biomarkers of HCC with high sensitivity and specificity. In addition, lncRNAs panel from serum and plasma has a relatively high diagnostic value for HCC patients from Asia.

XIST Induced by JPX Suppresses Hepatocellular Carcinoma by Sponging miR-155-5p

PURPOSE

The influence of X-inactive specific transcript (XIST) and X-chromosome inactivation associated long non-coding RNAs (lncRNAs) just proximal to XIST (JPX) on hepatocellular carcinoma (HCC) remains controversial in light of previous reports, which the present study aimed to verify.

MATERIALS AND METHODS

The DIANA lncRNA-microRNA (miRNA) interaction database was used to explore miRNA interactions with JPX or XIST. JPX, XIST, and miR-155-5p expression levels in paired HCC specimens and adjacent normal tissue were analyzed by RT-qPCR. Interaction between XIST and miR-155-5p was verified by dual luciferase reporter assay. Expression levels of miR-155-5p and its known target genes, SOX6 and PTEN, were verified by RT-qPCR and Western blot in HepG2 cells with or without XIST knock-in. The potential suppressive role of XIST and JPX on HCC was verified by cell functional assays and tumor formation assay using a xenograft model.

RESULTS

JPX and XIST expression was significantly decreased in HCC pathologic specimens, compared to adjacent tissue, which correlated with HCC progression and increased miR-155-5p expression. Dual luciferase reporter assay revealed XIST as a direct target of miR-155-5p. XIST knock-in significantly reduced miR-155-5p expression level and increased that of SOX6 and PTEN, while significantly inhibiting HepG2 cell growth in vitro, which was partially reversed by miR-155-5p mimic transfection. JPX knock-in significantly increased XIST expression and inhibited HepG2 cell growth in vitro or tumor formation in vivo in a XIST dependent manner.

CONCLUSION

JPX and XIST play a suppressive role in HCC. JPX increases expression levels of XIST in HCC cells, which suppresses HCC development by sponging the cancer promoting miR-155-5p.

X-inactive-specific transcript: A long noncoding RNA with complex roles in human cancers

The X-inactive-specific transcript (XIST/Xist) is one of the first long non-coding RNAs discovered in mammals and plays an essential role in X chromosome inactivation. XIST is dysregulated and acts as an oncogene or a tumor suppressor in different human malignancies. XIST is implicated in many aspects of carcinogenesis including tumor initiation, invasion, metastasis, apoptosis, cell cycle, stemness, autophagy, and drug resistance. This review focuses on research progress on the roles of XIST in tumor development. The multiple pathological functions of XIST in various cancers are systematically reviewed to elucidate the molecular basis of its biological roles and to provide new directions for future research.

The emergence of long non-coding RNAs in hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) accounting for roughly 90% of all primary liver neoplasms is the sixth most frequent neoplasm and the second prominent reason of tumor fatality worldwide. As regulators of diverse biological processes, long non-coding RNAs (lncRNAs) are involved in onset and development of neoplasms. With the continuous booming of well-featured lncRNAs in HCC from 2016 to now, we reviewed the newly-presented comprehension about the relationship between lncRNAs and HCC in this study. To be specific, we summarized the overview function and study tools of lncRNAs, elaborated the roles of lncRNAs in HCC, and sketched the molecule mechanisms of lncRNAs in HCC. In addition, the application of lncRNAs serving as biomarkers in early diagnosis and outcome prediction of HCC patients was highlighted.

Long non coding RNA XIST as a prognostic cancer marker - A meta-analysis

BACKGROUND

The X inactivate-specific transcript (XIST), derived from XIST gene, is aberrantly expressed in various cancers. High-expression of XIST is related to poor clinical outcome. This meta-analysis evaluated the potential role of XIST as novel predictor of prognosis in human cancer.

MATERIALS AND METHODS

This meta-analysis collected eligible studies about XIST and tumor prognosis through retrieving keywords in Web of Science, PubMed, Embase and the CNKI database, from 1993 to August 21, 2017. The quantitative meta-analysis was carried out with Stata SE12.0 and RevMan3.23 software. The aim was to determine whether XIST expression is associated with cancer prognosis and clinicopathology.

RESULTS

A total of 858 patients from 10 eligible studies were included in the final meta-analysis. Overall, a significant negative association between XIST and overall survival (OS) time (HR = 2.62, 95% CI: 2.18-3.14) was observed. Statistical significance was also showed in subgroup meta-analysis stratified by the country, sample size, follow-up and publication year. It was reported that increased XIST was positively related to advanced clinical TNM stage (OR = 4.03, 95% CI: 2.22-7.30), lymph node metastasis (LNM) (OR = 2.70, 95% CI: 1.73-4.21), distant metastasis (DM) (OR = 2.61, 95% CI: 1.57-4.33) and tumor size (OR = 3.10, 95% CI: 2.24-4.30).

CONCLUSIONS

LncRNA XIST may serve as a potential biomarker to predict solid tumor prognosis. This molecule can be effectively used to predict the clinical and pathological features of cancers.

Prognostic role of long non-coding RNA XIST expression in patients with solid tumors: a meta-analysis

BACKGROUND

The aberrant expression of long non-coding RNA (lncRNA) X inactivate-specific transcript (XIST) has been demonstrated to be involved in the tumourigenesis and the development of various cancers. Therefore, we conducted a meta-analysis to assess the prognostic role of lncRNA XIST expression in solid tumors.

METHODS

The databases of PubMed, EMBase, Web of Science, Cochrane library (up to Dec 31, 2017) were searched for the related studies and identified 15 eligible studies containing 1209 patients to include in the meta-analysis. Hazards ratios (HRs) with corresponding 95% confidence intervals (CIs) were pooled to estimate the association between lncRNA XIST expression and survival of cancer patients from Asian.

RESULTS

The result showed that higher lncRNA XIST expression in cancer tissue was related to a worse overall survival (OS) (HR = 1.54, 95% CI 1.07-2.23). In subgroup analysis, it revealed that lncRNA XIST overexpression was significantly associated with worse OS in digestive system tumors (HR = 1.67, 95% CI 1.11-2.51, p = 0.031). In addition, the association between high lncRNA XIST expression and poor OS was also statistically significant in other subgroups, including multivariate analysis (HR = 2.39, 95% CI 1.28-4.46, p = 0.006, random-effect), patients' number was greater than 65 (HR = 1.75, 95% CI 1.24-2.47, p = 0.001, random-effect), and reported in text (HR = 2.50, 95% CI 1.49-4.18, p = 0.000, random-effect).

CONCLUSIONS

The expression of lncRNA XIST could be regarded as a poor prognostic biomarker for solid tumors, which might shed new light on epigenetic diagnostics and therapeutics in tumors.

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 mRNAs 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.

Long non-coding RNA XIST as a potential prognostic biomarker in human cancers: a meta-analysis

Growing studies have confirmed that long non-coding RNAs (lncRNAs) involve in the occurrence and development of various cancers. XIST, as a lncRNA, was dysregulated in different cancers. This meta-analysis was performed to evaluate the prognostic potential of XIST in malignant tumors. Eight databases of PubMed, Web of Science, Embase, Cochrane library, CNKI, VIP, SinoMed and Wang Fang were comprehensively searched from their initiation date to August 15, 2017. A total of nine studies with 853 cancer patients met the including criteria were finally included in this meta-analysis after independently screening the literatures by two researchers. Any discrepancies were resolved by a consensus. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) for the primary endpoints were extracted and pooled for meta-analysis. Our results showed that expression level of XIST was markedly associated with overall survival (function as oncogene, HR = 0.53, 95% CI: 0.42-0.68, p < 0.00001; function as tumor suppressor, HR = 2.25, 95% CI: 1.15-4.37, p = 0.02), disease free survival (DFS)(HR = 0.45; 95% CI: 0.31-0.67, p < 0.0001), tumor type (digestive system carcinoma, HR = 0.50; 95% CI: 0.37-0.69, p < 0.00001; non-digestive system carcinoma, HR = 0.58; 95% CI: 0.39-0.87, p = 0.008), lymph node metastasis (OR = 0.32, 95% CI: 0.20-0.52, p < 0.00001), distant metastasis (OR = 0.36, 95% CI: 0.22-0.60, p < 0.0001) and tumor stage (OR = 0.43, 95% CI: 0.31-0.60, p < 0.00001). In conclusion, the pooled results in our current work suggest that XIST is an important prognostic biomarker in cancer patients.

lncRNAs as prognostic molecular biomarkers in hepatocellular carcinoma: a systematic review and meta-analysis

The latest studies have shown that long non-coding RNAs (lncRNAs) may be considered markers as their expression levels were abnormal in cancer and can be used as a molecular biomarker for the potential assessment of cancer prognosis. In this study, we aimed to assess the prognostic value of lncRNA as marker of patients with hepatocellular carcinoma. We performed a detailed search of the PubMed and Embase databases for articles on the prognostic value of various lncRNAs in HCC. We then carefully extracted the relevant data from the articles, and we used the meta-analysis method to analyze these results; heterogeneity and publication bias were also evaluated. With 40 associative studies included, we found that high expression of 27 types of lncRNA was associated with a poor prognosis in HCC patients, and low expression of 18 types of lncRNAs was associated with a worse prognosis. Patients with higher lncRNA expression had significantly poor overall survival (OS; pooled HR, 1.25; 95% confidence interval [CI], 1.03–1.52) as well as significantly poor recurrence-free survival (RFS; pooled HR, 1.66; 95% CI, 1.26–2.17). Overexpression of lncRNAs may not meaningfully predict disease-free survival (DFS; pooled HR, 1.04; 95% CI, 0.52–2.07; p = 0.91). Our meta-analysis demonstrated that lncRNAs may serve as predictive biomarkers for cancer prognosis.

Long non-coding RNA XIST regulates PTEN expression by sponging miR-181a and promotes hepatocellular carcinoma progression

BACKGROUND

Tumor metastasis often occurs in hepatocellular carcinoma (HCC) and influences the patient's prognosis, and microRNAs are reported to play key roles in tumor metastasis. This study was conducted to explore the effect of microRNAs on HCC metastasis.

METHODS

The levels of miR-181a in HCC tissues, adjacent tissues, metastatic HCC tissues, and non-metastatic HCC tissues at different stages were determined by qRT-PCR. Effect of miR-181a on the proliferation, invasion, and metastasis of HCC cells was estimated by cell counting kits-8 (CCK-8), wound-healing, and Transwell assays. Software analysis and luciferase assays were used to explore the target gene of miR-181a.

RESULTS

MiR-181a was up-regulated in HCC tissues and its expression level in metastatic HCC tissues was much higher than in non-metastasis samples. PTEN was found to be a target gene of miR-181a. MiR-181a had multiple binding sites with the long non-coding RNA (lncRNA) XIST. The regulation of miR-181a on PTEN was mediated by lncRNA XIST. The proliferation and invasion of cells with siXIST were significantly enhanced compared with those of control cells, while knockdown of miR-181a abolished the enhancing effects.

CONCLUSIONS

MiR-181a can promote HCC metastasis by targeting PTEN, which is regulated by lncRNA XIST.

Long noncoding RNAs as novel serum biomarkers for the diagnosis of hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

Long noncoding RNAs (lncRNAs) are outstanding as novel cancer biomarkers with great prospects. Herein, we focused on summarizing the overall diagnostic evaluation of lncRNAs for hepatocellular carcinoma (HCC).

METHODS

Relevant literature was collected from the online databases. The Quality Assessment for Studies of Diagnostic Accuracy checklist was used to assess the quality of included studies. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were plotted using random-effects models. Summary receiver operating characteristic curve and the area under the curve (AUC) were used to estimate the overall test performance. Statistical analysis was performed by STATA 14.0 and Meta-DiSc 1.4 software.

RESULTS

Ten studies with a total of 820 HCC patients and 785 healthy controls were included. For overall lncRNAs, the pooled sensitivity, specificity, and DOR to predict HCC patients were 80% [95% confidence interval (CI) 77-82%], 79% (95% CI 76-81%), and 27.66 (95% CI 14.26-53.63), respectively, corresponding to an AUC of 0.91.

CONCLUSIONS

LncRNAs were a high diagnostic value for HCC and its expression could potentially be used as auxiliary biomarker in confirming HCC.