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

Epigenetic modification-related mechanisms of hepatocellular carcinoma resistance to immune checkpoint inhibition

Hepatocellular carcinoma (HCC) constitutes most primary liver cancers and is one of the most lethal and life-threatening malignancies globally. Unfortunately, a substantial proportion of HCC patients are identified at an advanced stage that is unavailable for curative surgery. Thus, palliative therapies represented by multi-tyrosine kinase inhibitors (TKIs) sorafenib remained the front-line treatment over the past decades. Recently, the application of immune checkpoint inhibitors (ICIs), especially targeting the PD-1/PD-L1/CTLA-4 axis, has achieved an inspiring clinical breakthrough for treating unresectable solid tumors. However, many HCC patients with poor responses lead to limited benefits in clinical applications, which has quickly drawn researchers' attention to the regulatory mechanisms of immune checkpoints in HCC immune evasion. Evasion of immune surveillance by cancer is attributed to intricate reprogramming modulation in the tumor microenvironment. Currently, more and more studies have found that epigenetic modifications, such as chromatin structure remodeling, DNA methylation, histone post-translational modifications, and non-coding RNA levels, may contribute significantly to remodeling the tumor microenvironment to avoid immune clearance, affecting the efficacy of immunotherapy for HCC. This review summarizes the rapidly emerging progress of epigenetic-related changes during HCC resistance to ICIs and discusses the mechanisms of underlying epigenetic therapies available for surmounting immune resistance. Finally, we summarize the clinical advances in combining epigenetic therapies with immunotherapy, aiming to promote the formation of immune combination therapy strategies.

Function of the Long Noncoding RNAs in Hepatocellular Carcinoma: Classification, Molecular Mechanisms, and Significant Therapeutic Potentials

Hepatocellular carcinoma (HCC) is the most common and serious type of primary liver cancer. HCC patients have a high death rate and poor prognosis due to the lack of clear signs and inadequate treatment interventions. However, the molecular pathways that underpin HCC pathogenesis remain unclear. Long non-coding RNAs (lncRNAs), a new type of RNAs, have been found to play important roles in HCC. LncRNAs have the ability to influence gene expression and protein activity. Dysregulation of lncRNAs has been linked to a growing number of liver disorders, including HCC. As a result, improved understanding of lncRNAs could lead to new insights into HCC etiology, as well as new approaches for the early detection and treatment of HCC. The latest results with respect to the role of lncRNAs in controlling multiple pathways of HCC were summarized in this study. The processes by which lncRNAs influence HCC advancement by interacting with chromatin, RNAs, and proteins at the epigenetic, transcriptional, and post-transcriptional levels were examined. This critical review also highlights recent breakthroughs in lncRNA signaling pathways in HCC progression, shedding light on the potential applications of lncRNAs for HCC diagnosis and therapy.

Non-alcoholic fatty liver disease and hepatocellular carcinoma: Clinical challenges of an intriguing link

Non-alcoholic fatty liver disease (NAFLD) has emerged as the most common liver disorder worldwide mainly attributed to the epidemic spread of obesity and type 2 diabetes mellitus. Although it is considered a benign disease, NAFLD can progress to non-alcoholic steatohepatitis, liver cirrhosis and hepatocellular carcinoma (HCC). Most data regarding the epidemiology of NAFLD-related HCC are derived from cohort and population studies and show that its incidence is increasing as well as it is likely to emerge as the leading indication for liver transplantation, especially in the Western World. Although cirrhosis constitutes the main risk factor for HCC development, in patients with NAFLD, HCC can arise in the absence of cirrhosis, indicating specific carcinogenic molecular pathways. Since NAFLD as an underlying liver disease for HCC is often underdiagnosed due to lack of sufficient surveillance in this population, NAFLD-HCC patients are at advanced HCC stage at the time of diagnosis making the management of those patients clinically challenging and affecting their prognostic outcomes. In this current review, we summarize the latest literature on the epidemiology, other than liver cirrhosis-pathogenesis, risk factors and prognosis of NAFLD-HCC patients. Finally, we emphasize the prevention of the development of NAFLD-associated HCC and we provide some insight into the open questions and issues regarding the appropriate surveillance policies for those patients.

The identification and preliminary study of lncRNA TUG1 and its related genes in hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a common malignant tumour of the digestive system, which is a threat to public health. The purpose of this study was to investigate the featured genes and pathways of HCC from a bioinformatics database, and verify their correlation with diagnosis and prognosis of HCC.

MATERIAL AND METHODS

We downloaded the gene expression profile on HCC from the Gene Expression Omnibus (GEO), and software R was used to identify differentially expressed lncRNA (DEL). The target genes of the lncRNA were further predicted by using a cluster database and molecular interaction database. Subsequently, a combined interaction network of target genes was constructed using the Cytoscape platform with preliminary verification at the level of different databases, cell lines, and tissues. Finally, we explored the effectiveness of TUG1 and its target genes on the diagnosis and prognosis of HCC by univariate Cox analysis and survival analysis.

RESULTS

A total of four DELs were identified and the most remarkably up-regulated lncRNA was TUG1, which included 12 high-confidence target genes. Moreover, we found that the expression changes of TUG1 and its target genes in different databases, cell lines, and liver cancer tissues were consistent with the prediction. The high expression of TUG1 and its target genes could significantly predict the shorter survival time of HCC patients, among which NCAPG, MCM6, PIGC, PEA15, and RACGAP1 have significant diagnostic value for HCC (AUC > 0.9).

CONCLUSIONS

This study provides a starting point for the screening of therapeutically relevant targets in HCC. Further experiment should be conducted to verify our findings.

Molecular classification of hepatocellular carcinoma: prognostic importance and clinical applications

Hepatocellular carcinoma (HCC) is a lethal human malignancy with a very low overall and long-term survival rate. Poor prognostic outcomes are predominantly associated with HCC due to a huge landscape of heterogeneity found in the deadliest disease. However, molecular subtyping of HCC has significantly improved the knowledge of the underlying mechanisms that contribute towards the heterogeneity and progression of the disease. In this review, we have extensively summarized the current information available about molecular classification of HCC. This review can be of great significance for providing the insight information needed for development of novel, efficient and personalized therapeutic options for the treatment of HCC patients globally.

DCP1A is an unfavorable prognostic-related enhancer RNA in hepatocellular carcinoma

Long non-coding RNAs (lncRNAs) are associated with occurrence and development of tumors. Enhancer RNA (eRNA) is a special type of lncRNAs produced from transcription of enhancer elements. The function of eRNAs in tumors have elicited significant attention recently. However, the clinical significance and role of eRNAs in hepatocellular carcinoma (HCC) has not been fully explored. The current study sought to explore the expression level and prognostic value of key eRNAs in HCC. Bioinformatics analyses were used to explore expression levels of key prognostic eRNAs in HCC and their correlation with target genes. A total of 1580 enhancer RNAs (eRNAs) and 1791 target genes were initially retrieved from TCGA-LIHC gene expression database. Further analysis through survival and correlation analysis led to identification of 12 eRNAs and 13 target genes. The findings showed that DCP1A was the most prognosis-related eRNA. This eRNA showed the highest correlation with the target gene, PRKCD. Analysis showed that poor overall survival (OS) in HCC patients was correlated with high expression level of DCP1A (eRNA) and PRKCD (target gene). The up-regulation of DCP1A was associated with advanced tumor stage, larger tumor size and higher histological grade. The results of pan-cancer analysis showed that the expression of DCP1A was differentially expressed in 13 other types of tumor tissues and their corresponding normal tissues. This eRNA was highly expressed in digestive system tumors. Functional analysis showed that high expression level of DCP1A was implicated in multiple tumor-related signaling pathways. The findings of the current study indicated DCP1A is a novel biomarker that can be used as a potential therapeutic target for HCC patients.

Long non‑coding RNA ZSCAN16‑AS1 promotes the malignant properties of hepatocellular carcinoma by decoying microRNA‑451a and consequently increasing ATF2 expression

The importance of long noncoding RNAs (lncRNAs) in the oncogenicity of hepatocellular carcinoma (HCC) has been widely studied. However, the detailed functions of ZSCAN16 antisense RNA 1 (ZSCAN16‑AS1) have seldom been explored in HCC until the present study. In the present study, experiments were performed to clarify whether ZSCAN16‑AS1 is implicated in the oncogenesis and progression of HCC and to explore the possible underlying mechanisms. ZSCAN16‑AS1 expression was analyzed using reverse transcription‑quantitative PCR. The effects of ZSCAN16‑AS1 on the biological behavior of HCC cells were demonstrated by functional experiments. The direct binding capacity of ZSCAN16‑AS1 with microRNA‑451a (miR‑451a) was indicated by the luciferase reporter assay and RNA immunoprecipitation. The high expression of ZSCAN16‑AS1 was confirmed in HCC by The Cancer Genome Atlas database and the cohort of the present study. Survival data revealed that patients with a high ZSCAN16‑AS1 level had worse prognosis compared with those with a low ZSCAN16‑AS1 level. Following ZSCAN16‑AS1 knockdown, HCC cell proliferation, migration and invasion were curbed, whereas cell apoptosis was promoted in vitro. The absence of ZSCAN16‑AS1 restricted tumor growth of HCC cells in vivo. Mechanistically, ZSCAN16‑AS1 acted as a competing endogenous RNA by decoying miR‑451a in HCC cells. Furthermore, activating transcription factor 2 (ATF2), a direct target of miR‑451a, was under the regulation of ZSCAN16‑AS1, which was exerted by sequestering miR‑451a. In addition, miR‑451a knockdown or ATF2 resumption reversed the proliferation suppression, apoptosis promotion and migration and invasion inhibition triggered by ZSCAN16‑AS1 silencing. In conclusion, ZSCAN16‑AS1, a pro‑oncogenic lncRNA, aggravated the malignancy of HCC by controlling the miR‑451a/ATF2 axis. An understanding of the competing endogenous RNA network of ZSCAN16‑AS1/miR‑451a/ATF2 in HCC might be instrumental in the development of attractive targets for molecular therapy.

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 immune-related lncRNA signature for predicting immune checkpoint blockade and prognosis in hepatocellular carcinoma

BACKGROUND

An increasing body of evidence has supported that long non-coding RNAs (lncRNAs) can play as essential roles of various physiological process and pathological diseases. We aimed to construct a robust immune-associated lncRNA signature associated with the prognosis for HCC survival prediction.

METHODS

7 immune-associated lncRNAs presenting significant correlation with survival were screened through stepwise univariate Cox regression and LASSO algorithm, and multivariate Cox regression. Kaplan-Meier analysis, proportional hazards model, and ROC analyses further conducted. Gene set enrichment analysis (GSEA) was applied for functional annotation. We conducted quantitative real-time polymerase chain reaction to determine NRAV expression and preliminarily explored the latent role of NRAV in prognosis of HCC patients.

RESULTS

Finally, 7 immune-related lncRNA signature composed of AC007405.3, AC023157.3, NRAV, CASC19, MSC-AS1, GASAL1, and LINC00942 were validated. This lncRNAs signature can serve as an independent predictive biomolecular factor. This signature was further confirmed in the validation group and the entire cohort. We demonstrated that NRAV was significantly upregulated in HCC cell lines and it may serve as a key regulator in HCC. Our signature was associated to apoptosis and immunologic characteristics. This signature mediated immune cell infiltration (i.e., Dendritic, etc.,) and immune checkpoint blockade (ICB) immunotherapy-related molecules (i.e., CD274, etc.,).

CONCLUSION

This immune-related lncRNA signature possesses promising prognostic value in HCC and may have the potentiality to predict clinical outcome of ICB immunotherapy.

Hepigenetics: A Review of Epigenetic Modulators and Potential Therapies in Hepatocellular Carcinoma

Hepatocellular carcinoma is the fifth most common cancer worldwide and the second most lethal, following lung cancer. Currently applied therapeutic practices rely on surgical resection, chemotherapy and radiotherapy, or a combination thereof. These treatment options are associated with extreme adversities, and risk/benefit ratios do not always work in patients' favor. Anomalies of the epigenome lie at the epicenter of aberrant molecular mechanisms by which the disease develops and progresses. Modulation of these anomalous events poses a promising prospect for alternative treatment options, with an abundance of felicitous results reported in recent years. Herein, the most recent epigenetic modulators in hepatocellular carcinoma are recapitulated on.

Transcriptomic profiling of long non-coding RNAs in non-virus associated hepatocellular carcinoma

Due to falling prevalence of viral hepatitis (VH), obesity, alcoholism and related liver diseases have become increasingly frequent and important as causes of hepatocellular carcinoma (HCC). However, mechanisms underlying hepatocarcinogenesis and tumor progression in VH-negative HCC remain poorly understood. Long non-coding RNAs (lncRNAs) have been implicated in pathogenesis of human diseases, including HCC. Here, by analyzing 20 clinical samples' RNA-sequencing data generated from 8 VH-negative and 2 VH-positive HCC patients, we have identified and characterized 1,514 candidate lncRNAs. For differentially expressed genes (DEGs) between tumor tissues and adjacent non-tumor tissues (P < 0.05, |FC| > 2), the upregulated genes were mainly involved in the cell proliferation, and the downregulated genes mediated the metabolic processes and responses to oxidative stress, inflammation and toxic substances. Furthermore, the lncRNA-mRNA co-expression network was constructed, by which two genetic aberrations with high frequency in HCC, SPATA46 and TMEM78, were identified. In addition, we identified 16 DEGs between tumor issues from VH-negative and VH-positive HCC patients with aim to explore gene expression differences that could be involved in the pathogenesis of HCC with varying etiology. In conclusion, we performed the comprehensive analysis of lncRNA and mRNA expression profiles, which could provide valuable insights into the underlying genetic alteration in non-virus associated HCC.

Role of microRNA and Long Non-Coding RNA in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for about 80-90% of all liver cancers and is found to be the third most common cause of cancer mortality in the Asia-Pacific region. Risk factors include hepatitis B and C virus, cirrhosis, aflatoxin-contaminated food, alcohol, and diabetes. Surgically removing the tumor tissue seems effective but a high chance of recurrence has led to an urgent need to develop novel molecules for the treatment of HCC. Clinical management with sorafenib is found to be effective but it is only able to prolong survival for a few months. Various side effects like gastrointestinal and abdominal pain, hypertension, and hemorrhage are also associated with sorafenib, which calls for the unmet need of effective therapies against HCC. Similarly, the genetic mechanisms behind the occurrence of HCC are still unknown and need to be expounded further for developing newer candidates. Since unearthing the concept of these variants, transcriptomics has revealed the role of non-coding RNAs (ncRNAs) in many cellular, physiological and pathobiological processes. They are also found to be widely associated and abundantly expressed in a variety of cancer. Aberrant expression and mutations are closely related to tumorigenesis and metastasis and hence are classified as novel biomarkers and therapeutic targets for the treatment of cancer, including HCC. Herein, this review summarises the relationship between ncRNAs and hepatocellular carcinoma.

linc00174-EZH2-ZNF24/Runx1-VEGFA Regulatory Mechanism Modulates Post-burn Wound Healing

Preservation of denatured dermis exerts promotive functions in wound healing and improves the appearance and function of skin. Angiogenesis is crucial for wound healing during burn injury. However, the potential molecular mechanism of angiogenesis in the recovery after burn injury remains to be elucidated. Herein, RNA chromatin immunoprecipitation (ChIP) sequencing analysis revealed upregulation of long intergenic non-coding RNA 00174 (linc00174) in the post-burn tissues. linc00174 overexpression promoted angiogenic activities of human umbilical vein endothelial cells (HUVECs) in the heat-denatured cell model, characterized by the promotion of cell proliferation, migration, and tube formation. Mechanistically, linc00174 directly bound to enhancer of zeste homolog 2 (EZH2), thus stimulating the protein level of trimethylation at lysine 27 of histone H3 (H3K27me3). Moreover, inhibition of EZH2 resulted in downregulation of ZNF24 and Runx1, as well as a decline of vascular endothelial growth factor A (VEGFA). Furthermore, EZH2 modulated epigenetic repression of ZNF24 and Runx1 through the promoter of H3K27me3. Additionally, ZNF24 and Runx1 both functioned as transcriptional inhibitors of VEGFA. Taken together, these findings uncover that linc00174 epigenetically inhibits ZNF24 and Runx1 expression through binding to EZH2, thus attenuating the suppression of VEGFA, contributing to the facilitation of angiogenesis during the recovery of heat-denatured endothelial cells.

LncRNAs Act as a Link between Chronic Liver Disease and Hepatocellular Carcinoma

Long non-coding RNAs (lncRNAs) are emerging as important contributors to the biological processes underlying the pathophysiology of various human diseases, including hepatocellular carcinoma (HCC). However, the involvement of these molecules in chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD) and viral hepatitis, has only recently been considered in scientific research. While extensive studies on the pathogenesis of the development of HCC from hepatic fibrosis have been conducted, their regulatory molecular mechanisms are still only partially understood. The underlying mechanisms related to lncRNAs leading to HCC from chronic liver diseases and cirrhosis have not yet been entirely elucidated. Therefore, elucidating the functional roles of lncRNAs in chronic liver disease and HCC can contribute to a better understanding of the molecular mechanisms, and may help in developing novel diagnostic biomarkers and therapeutic targets for HCC, as well as in preventing the progression of chronic liver disease to HCC. Here, we comprehensively review and briefly summarize some lncRNAs that participate in both hepatic fibrosis and HCC.

Advances in the early diagnosis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers globally. In contrast to the declining death rates observed for all other common cancers such as breast, lung, and prostate cancers, the death rates for HCC continue to increase by ~2–3% per year because HCC is frequently diagnosed late and there is no curative therapy for an advanced HCC. The early diagnosis of HCC is truly a big challenge. Over the past years, the early diagnosis of HCC has relied on surveillance with ultrasonography (US) and serological assessments of alpha-fetoprotein (AFP). However, the specificity and sensitivity of US/AFP is not satisfactory enough to detect early onset HCC. Recent technological advancements offer hope for early HCC diagnosis. Herein, we review the progress made in HCC diagnostics, with a focus on emerging imaging techniques and biomarkers for early disease diagnosis.

The Burden of Hepatocellular Carcinoma in Non-Alcoholic Fatty Liver Disease: Screening Issue and Future Perspectives

In recent decades, non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in the Western world, and the occurrence of its complications, such as hepatocellular carcinoma (HCC), has rapidly increased. Obesity and diabetes are considered not only the main triggers for the development of the disease, but also two independent risk factors for HCC. Single nucleotide polymorphisms (such as PNPLA3, TM6SF2 and MBOAT7) are related to the susceptibility to the development of HCC and its progression. Therefore, an appropriate follow-up of these patients is needed for the early diagnosis and treatment of HCC. To date, international guidelines recommend the use of ultrasonography with or without alpha-fetoprotein (AFP) in patients with advanced fibrosis. Furthermore, the use of non-invasive tools could represent a strategy to implement surveillance performance. In this review, we analyzed the main risk factors of NAFLD-related HCC, the validated screening methods and the future perspectives.

Jatrorrhizine inhibits colorectal carcinoma proliferation and metastasis through Wnt/β-catenin signaling pathway and epithelial-mesenchymal transition

Purpose

Jatrorrhizine (JAT) is a natural protoberberine alkaloid, possesses detoxification, bactericidal and hypoglycemic activities. However, its anti-cancer mechanism is not clear. This study aimed to investigate the mechanism of JAT through which inhibits colorectal cancer in HCT-116 and HT-29 cells.

Methods

MTT assay and colony formation assay were used to check the cell proliferation ability. Cell apoptosis and cell cycle were measured by Hoechst 33342 staining and flow cytometry, respectively. Cell migration and invasion were detected by scratch wound healing assay and trans-well assay, respectively. Further, expression of related proteins was examined via Western blotting and the in vivo anti-cancer effect of JAT was confirmed by nude mice xenograft model.

Results

The research showed that JAT inhibited the proliferation of HCT-116 and HT-29 cells with IC₅₀ values of 6.75±0.29 μM and 5.29±0.13 μM, respectively, for 72 hrs. It has also showed a time dependently, cell cycle arrested in S phase, promoted cell apoptosis and suppressed cell migration and invasion. In addition, JAT inhibited Wnt signaling pathway by reducing β-catenin and increasing GSK-3β expressions. Increased expression of E-cadherin, while decreased N-cadherin, indicating that JAT treatment suppressed the process of cell epithelial–mesenchymal transition (EMT). In HCT-116 nude mice xenograft model, JAT inhibited tumor growth and metastasis, and induced apoptosis of tumor cells.

Conclusion

This study demonstrated that JAT efficiently inhibited colorectal cancer cells growth and metastasis, which provides a new point for clinical treatment of colorectal cancer.

Mechanisms of hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. It is the second leading cause of cancer-related deaths worldwide, with a very poor prognosis. In the United States, there has been only minimal improvement in the prognosis for HCC patients over the past 15 years. Details of the molecular mechanisms and other mechanisms of HCC progression remain unclear. Consequently, there is an urgent need for better understanding of these mechanisms. HCC is often diagnosed at advanced stages, and most patients will therefore need systemic therapy, with sorafenib being the most common at the present time. However, sorafenib therapy only minimally enhances patient survival. This review provides a summary of some of the known mechanisms that either cause HCC or contribute to its progression. Included in this review are the roles of viral hepatitis, non-viral hepatitis, chronic alcohol intake, genetic predisposition and congenital abnormalities, toxic exposures, and autoimmune diseases of the liver. Well-established molecular mechanisms of HCC progression such as epithelial-mesenchymal transition, tumor-stromal interactions and the tumor microenvironment, cancer stem cells, and senescence bypass are also discussed. Additionally, we discuss the roles of circulating tumor cells, immunomodulation, and neural regulation as potential new mechanisms of HCC progression. A better understanding of these mechanisms could have implications for the development of novel and more effective therapeutic and prognostic strategies, which are critically needed.

Integrated traditional Chinese and Western medicine in hepatocellular carcinoma treatment

As the branches of oncology become more and more detailed, its deficiencies gradually appear in clinical work in recent years. With the development of modern medicine, individualized treatment of hepatocellular carcinoma (HCC) has already been more emphasized in clinical work. This article reviews the diagnosis and treatment of HCC, which can be regarded as an organic systemic disease, based on a concept of integrated medicine. It is suggested that simply eliminating cancer lesions does not mean curing HCC. In clinical practice, it is necessary to use integrative thoughts such as basic study combined with clinical practice, medicine with pharmacy, traditional Chinese medicine with Western medicine, local with whole, etc, so as to find new integrative methods for diagnosis and treatment of HCC.

A novel lncRNA, TCONS_00006195, represses hepatocellular carcinoma progression by inhibiting enzymatic activity of ENO1

Hepatocellular carcinoma (HCC) is one of the most common malignancies and has an unfavorable prognosis. The hepatitis B virus X (HBx) protein has been reported to be closely associated with hepatocarcinogenesis. Meanwhile, emerging evidence has indicated that long noncoding RNAs (lncRNAs) are involved in the pathogenesis and progression of cancers. Our previous investigation has demonstrated that HBx could promote HCC by regulating the expression levels of various lncRNAs. In this study, we identified an lncRNA, lncRNA-TCONS_00006195 (termed lncRNA-6195), which was downregulated in HBV-related HCC tissues compared with its expression in adjacent noncancerous hepatic tissues. Clinical data showed that a low level of lncRNA-6195 was correlated with a high Edmondson–Steiner grade of the tumor and a poor prognosis in HCC patients. Furthermore, lncRNA-6195 acted as a tumor repressor in the development of hepatitis B-related HCC, inhibiting HCC cell proliferation in vitro and in vivo. Moreover, lncRNA-6195 could combine with α-enolase (ENO1) and repress its enzymatic activity, thus further inhibiting the energy metabolism in HCC cells. Our results suggest that lncRNA-6195 represses the growth of HCC by inhibiting the enzymatic activity of ENO1. These findings provide new insights into the mechanisms underlying the lncRNA involvement in hepatocarcinogenesis and can serve as a basis for the development of novel strategies to hinder HCC.

Down-regulation of argininosuccinate lyase induces hepatoma cell apoptosis through activating Bax signaling pathway

Argininosuccinate lyase (ASL) plays an important role in the hepatic urea cycle, and can catalyze the reversible reaction of argininosuccinate to arginine and fumarate. However, the function of ASL in hepatocellular carcinoma (HCC) is not fully understood. In this study, we found that ASL expression was frequently upregulated in HCC tissues and HCC cell lines. Knock down of ASL inhibited cell proliferation and induced apoptosis in HCC cells. Mechanistic studies revealed the BCL2-associated X protein (Bax) signaling pathway which determines cancer cell apoptosis was regulated by ASL. Moreover, the depletion of Bax restored the inhibition of cell growth and reduced apoptosis initiated by ASL silencing. Together, the study demonstrated that ASL regulated HCC cell growth and apoptosis by modulating Bax signaling. Thus, the therapeutic targeting of ASL may offer options for HCC treatment.

Super-Enhancer-Associated Long Noncoding RNA HCCL5 Is Activated by ZEB1 and Promotes the Malignancy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most dominant causes of neoplasm-related deaths worldwide. In this study, we identify and characterize HCCL5, a novel cytoplasmic long noncoding RNA (lncRNA), as a crucial oncogene in HCC. HCCL5 promoted cell growth, G₁-S transition, invasion, and metastasis while inhibiting apoptosis of HCC cells both in vitro and in vivo. Moreover, HCCL5 was upregulated in TGF-β1-induced classical epithelial-to-mesenchymal transition (EMT) models, and this lncRNA in turn accelerated the EMT phenotype by upregulating the expression of transcription factors Snail, Slug, ZEB1, and Twist1. HCCL5 was transcriptionally driven by ZEB1 via a super-enhancer and was significantly and frequently overexpressed in human HCC tissues, correlating with worse overall survival of patients with HCC. Together, this study characterizes HCCL5 as a super-enhancer-driven lncRNA promoting HCC cell viability, migration, and EMT. Our data also suggest that HCCL5 may serve as a novel prognostic biomarker and therapeutic target in HCC. SIGNIFICANCE: These findings identify the lncRNA HCCL5 as a super-enhancer-driven oncogenic factor that promotes the malignancy of hepatocellular carcinoma.

DANCR contributed to hepatocellular carcinoma malignancy via sponging miR-216a-5p and modulating KLF12

Long noncoding RNA (lncRNA) differentiation antagonizing nonprotein coding RNA (DANCR) has been identified as an oncogene in several cancers. However, the biological function and role of DANCR in hepatocellular carcinoma (HCC) remain unclear. Our current study aimed to investigate the detailed mechanism of DANCR in HCC. We found that DANCR was significantly upregulated in HCC cell lines in comparison to LO2 cells. Then, we observed that knockdown of DANCR could greatly inhibit Huh7 and HepG2 cell proliferation. In addition, HCC cell apoptosis was increased by silence of DANCR and meanwhile, cell cycle progression was blocked in G1 phase. Apart from these, downregulation of DANCR repressed HCC cell migration and invasion ability obviously. As predicted by the bioinformatics analysis, microRNA-216a-5p (miR-216a-5p) could serve as a direct target of DANCR. MiR-216a-5p has been reported to be involved in many cancers. Here, the correlation between miR-216a-5p and DANCR was confirmed using dual-luciferase reporter assay and radioimmunoprecipitation assay. Subsequently, Kruppel-like factor 12 (KLF12) exerts an important role in different tumor types. KLF12 can function as a downstream target of miR-216a-5p. Finally, the in vivo experiments were used and the data proved that DANCR also strongly suppressed HCC tumor growth in vivo via targeting miR-216a-5p and KLF12. In conclusion, our study indicated that DANCR might provide a new perspective for HCC treatment.

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.