Long Noncoding RNAs Act as Novel Biomarkers for Hepatocellular Carcinoma: Progress and Prospects

c-FLIP/Ku70 complex; A potential molecular target for apoptosis induction in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide and the most common form of liver cancer. Despite global efforts toward early diagnosis and effective treatments, HCC is often diagnosed at advanced stages, where conventional therapies frequently lead to resistance and/or high recurrence rates. Therefore, novel biomarkers and promising medications are urgently required. Epi-drugs, or epigenetic-based medicines, have recently emerged as a promising therapeutic modality. Since the epigenome of the cancer cells is always dysregulated and this is followed by apoptosis-resistance, reprogramming the epigenome of cancer cells by epi-drugs (such as HDAC inhibitors (HDACis), and DNMT inhibitors (DNMTis)) could be an alternative approach to use in concert with established treatment protocols. C-FLIP, an anti-apoptotic protein, and Ku70, a member of the DNA repair system, bind together and make a cytoplasmic complex in certain cancers and induce resistance to apoptosis. Many epi-drugs, such as HDACis, can dissociate this complex through Ku70 acetylation and activate cellular apoptosis. The novel compounds for dissociating this complex could provide an innovative insight into molecular targeted HCC treatments. In this review, we address the innovative therapeutic potential of targeting c-FLIP/Ku70 complex by epi-drugs, particularly HDACis, to overcome apoptosis resistance of HCC cells. This review will cover the mechanisms by which the c-FLIP/Ku70 complex facilitates cancer cell survival, the impact of epigenetic alterations on the complex dissociation, and highlight HDACis potential in combination therapies, biomarker developments and mechanistic overviews. This review highlights c-FLIP ubiquitination and Ku70 acetylation levels as diagnostic and prognostic tools in HCC management.

Identification and validation of a five-necroptosis-related lncRNAs signature for prognostic prediction in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is among the most prevalent digestive system malignancies and is associated with a poor prognosis. Necroptosis, a form of regulated death mediated by death receptors, exhibits characteristics of both necrosis and apoptosis. Long non-coding RNAs (lncRNAs) have been identified as crucial regulators in tumor necroptosis. This study aims to identify the necroptosis-related lncRNAs (np-lncRNA) in HCC and investigate their relationships with prognosis.

Method

The RNA-sequencing data, along with clinicopathological and survival information of HCC patients were sourced from The Cancer Genome Atlas (TCGA) database. The np-lncRNAs were analyzed to assess their potential in predicting HCC prognosis. Prognostic signatures related to necroptosis were constructed using stepwise multivariate Cox regression analysis. The prognosis of patients was compared using Kaplan-Meier (KM) analysis. The accuracy of the prognostic signature was evaluated using Receiver operating characteristic (ROC) analysis and decision curve analysis (DCA). Quantitative real-time polymerase chain reaction(qPCR) was employed to validate the lncRNAs expression levels of lncRNAs among samples from an independent cohort.

Results

The np-lncRNAs ZFPM2-AS1, AC099850.3, BACE1-AS, KDM4A-AS1 and MKLN1-AS were identified as potential prognostic biomarkers. The prognostic signature constructed from these np-lncRNAs achieved an Area Under the Curve (AUC) of 0.773. Based on the risk score derived from the signature, patients were divided into two groups, with the high-risk group exhibiting poorer overall survival. Gene Set Enrichment Analysis (GSEA) revealed significantly different between the low risk and high risk groups in tumor-related pathways (such as mTOR, MAPK and p53 signaling pathways) and immune-related functions (like T cell receptor signaling pathway and natural killer cell mediated cytotoxicity). The increased expression of np-lncRNAs was confirmed in another independent HCC cohort.

Conclusions

This signature offers a dependable method for forecasting the prognosis of HCC patients. Our findings indicate a subset of np-lncRNA biomarkers that could be utilized for prognosis prediction and personalized treatment strategies of HCC patients.

The role of long non-coding RNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent liver malignancy with complex etiology and generally poor prognosis. Recently, long non-coding RNAs (lncRNAs), non-protein-coding RNA molecules exceeding 200 nucleotides, have emerged as pivotal players in HCC, influencing its initiation, progression, invasion, and metastasis. These lncRNAs modulate gene expression at epigenetic, transcriptional, and post-transcriptional levels, actively participating in the pathological and physiological processes of HCC. Understanding the intricate relationship between lncRNAs and HCC is important for improving prognosis and reducing mortality. This review summarizes advancements in elucidating the role of lncRNAs in HCC pathogenesis.

Long Noncoding RNAs MALAT1 and HOTTIP Act as Serum Biomarkers for Hepatocellular Carcinoma

BACKGROUND

Circulating tumor markers with satisfactory sensitivity and specificity play crucial roles in cancer diagnosis and therapy. This prospective study aimed to evaluate the potential of circulating lncRNAs as biomarkers for hepatocellular carcinoma (HCC).

METHODS

A total of 74 patients with HCC and 94 healthy controls were enrolled. The expression levels of candidate genes in serum were detected by qRT-PCR. Receiver operating characteristic (ROC) curve analysis and logistic regression were employed to investigate the diagnostic capacity of lncRNAs. The analysis of 3-year overall survival (OS) was conducted using the Kaplan-Meier method and log-rank test.

RESULTS

Of the 9 candidate genes, 6 lncRNAs could be stably detected in serum. The expression levels of circulating MALAT1 and HOTTIP in HCC patients were significantly higher than those in controls (P < 0.001). ROC analysis showed that MALAT1 and HOTTIP were more effective than alpha-fetoprotein (AFP) (P < 0.010) in the diagnosis of HCC, with AUCs of 0.896 and 0.899, respectively. Additionally, a panel consisting of MALAT1, HOTTIP, and AFP was constructed to obtain an AUC of 0.968 with a sensitivity of 87.8% and specificity of 94.7% in HCC diagnosis. Moreover, the upregulation of MALAT1 was not only related to multiple tumor lesions, HCV infection, AST level, and AFP level, but also suggested shorter OS. A high expression level of HOTTIP was associated with metastasis.

CONCLUSION

Serum MALAT1 and HOTTIP play indicative roles as non-invasive biomarkers for HCC.

Role of lncRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is among the deadliest cancer in human malignancies. It is the most common and severe type of primary liver cancer. However, the molecular mechanisms underlying HCC pathogenesis remain poorly understood. Long non-coding RNAs (lncRNAs), a new kind of RNA and epigenetic factors, play a crucial role in tumorigenesis and the progression of HCC. LncRNAs are capable of promoting the autophagy, proliferation, and migration of tumor cells by targeting and modulating the expression of downstream genes in signaling pathways related to cancer; these transcripts modify the activity and expression of various tumor suppressors and oncogenes. LncRNAs could act as biomarkers for treatment approaches such as immunotherapy, chemotherapy, and surgery to effectively treat HCC patients. Improved knowledge regarding the aetiology of HCC may result from an advanced understanding of lncRNAs. Enhanced oxidative stress in the mitochondrial and Endoplasmic reticulum leads to the activation of unfolded protein response pathway that plays a crucial role in the pathophysiology of hepatocellular carcinoma. The mutual regulation between LncRNAs and Endoplasmic reticulum (ER) stress in cancer and simultaneous activation of the unfolded protein response (UPR) pathway determines the fate of tumor cells in HCC. Mitochondria-associated lncRNAs work as essential components of several gene regulatory networks; abnormal regulation of mitochondria-associated lncRNAs may lead to oncogenesis, which provides further insight into the understanding of tumorigenesis and therapeutic 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.

LncRNA SNHG1 activates glycolysis to promote hepatocellular cancer progression through miR-326/PKM2 axis

AIMS

Hepatocellular cancer (HCC) is a lethal malignancy with extremely poor prognosis. Here, we attempted to investigate the role and underlying mechanism of SNHG1 in HCC progression.

METHODS

Combined with bioinformatics and experimental validation, we explored the clinical significance of SNHG1 in HCC. CCK8, cell colony formation assay, and subcutaneous tumorigenesis experiments of nude mice were conducted to evaluate the pro-proliferative capacity of SNHG1. Glucose consumption and lactate production were measured to explore the regulatory role of SNHG1 in glycolysis. Nuclear-cytoplasmic separation, qRT-PCR and Western blot assays, chromatin immunoprecipitation, luciferase reporter and RNA immunoprecipitation assays were performed to investigate the molecular mechanisms of SNHG1 in HCC.

RESULTS

SNHG1 expression was dramatically increased in HCC and positively correlated with poor prognosis. It was E2F1 that bound to SNHG1 promoter region to activate SNHG1 transcription. Furthermore, SNHG1 served as a molecular sponge for miR-326 to sequester the interaction of miR-326 and PKM2, facilitating the expression of PKM2. Activating PKM2 expression was evidenced to be one of mechanisms of SNHG1 to promote glycolysis and proliferation of HCC cells.

CONCLUSION

E2F1-activated SNHG1 modulates miR-326/PKM2 axis to facilitate glycolysis and proliferation of HCC cells. Targeting SNHG1 could be a promising therapeutic option for HCC.

LncRNAs and the Angiogenic Switch in Cancer: Clinical Significance and Therapeutic Opportunities

Angiogenesis is one of the hallmarks of cancer, and the establishment of new blood vessels is vital to allow for a tumour to grow beyond 1-2 mm in size. The angiogenic switch is the term given to the point where the number or activity of the pro-angiogenic factors exceeds that of the anti-angiogenic factors, resulting in the angiogenic process proceeding, giving rise to new blood vessels accompanied by increased tumour growth, metastasis, and potential drug resistance. Long noncoding ribonucleic acids (lncRNAs) have been found to play a role in the angiogenic switch by regulating gene expression, transcription, translation, and post translation modification. In this regard they play both anti-angiogenic and pro-angiogenic roles. The expression levels of the pro-angiogenic lncRNAs have been found to correlate with patient survival. These lncRNAs are also potential drug targets for the development of therapies that will inhibit or modify tumour angiogenesis. Here we review the roles of lncRNAs in regulating the angiogenic switch. We cover specific examples of both pro and anti-angiogenic lncRNAs and discuss their potential use as both prognostic biomarkers and targets for the development of future therapies.

Identifying novel transcript biomarkers for hepatocellular carcinoma (HCC) using RNA-Seq datasets and machine learning

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death in the world owing to limitations in its prognosis. The current prognosis approaches include radiological examination and detection of serum biomarkers, however, both have limited efficiency and are ineffective in early prognosis. Due to such limitations, we propose to use RNA-Seq data for evaluating putative higher accuracy biomarkers at the transcript level that could help in early prognosis.

METHODS

To identify such potential transcript biomarkers, RNA-Seq data for healthy liver and various HCC cell models were subjected to five different machine learning algorithms: random forest, K-nearest neighbor, Naïve Bayes, support vector machine, and neural networks. Various metrics, namely sensitivity, specificity, MCC, informedness, and AUC-ROC (except for support vector machine) were evaluated. The algorithms that produced the highest values for all metrics were chosen to extract the top features that were subjected to recursive feature elimination. Through recursive feature elimination, the least number of features were obtained to differentiate between the healthy and HCC cell models.

RESULTS

From the metrics used, it is demonstrated that the efficiency of the known protein biomarkers for HCC is comparatively lower than complete transcriptomics data. Among the different machine learning algorithms, random forest and support vector machine demonstrated the best performance. Using recursive feature elimination on top features of random forest and support vector machine three transcripts were selected that had an accuracy of 0.97 and kappa of 0.93. Of the three transcripts, two were protein coding (PARP2-202 and SPON2-203) and one was a non-coding transcript (CYREN-211). Lastly, we demonstrated that these three selected transcripts outperformed randomly taken three transcripts (15,000 combinations), hence were not chance findings, and could then be an interesting candidate for new HCC biomarker development.

CONCLUSION

Using RNA-Seq data combined with machine learning approaches can aid in finding novel transcript biomarkers. The three biomarkers identified: PARP2-202, SPON2-203, and CYREN-211, presented the highest accuracy among all other transcripts in differentiating the healthy and HCC cell models. The machine learning pipeline developed in this study can be used for any RNA-Seq dataset to find novel transcript biomarkers. Code: www.github.com/rajinder4489/ML_biomarkers.

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.

Antineoplastic Activity of Chrysin against Human Hepatocellular Carcinoma: New Insight on GPC3/SULF2 Axis and lncRNA-AF085935 Expression

The natural flavonoid chrysin possesses antiproliferative activity against various types of cancers, including hepatocellular carcinoma (HCC), which is a common malignancy. However, the exact mechanism of chrysin antiproliferative activity remains unclear. This research was executed to explore the impact of chrysin on glypican-3 (GPC3)/sulfatase-2 (SULF2) axis and lncRNA-AF085935 expression in HCC using HepG2 cells. Cisplatin (20, 50, 100 μg/mL), chrysin (15, 30, and 60 μg/mL) and the combination of 50 μg/mL cisplatin with different concentrations of chrysin were applied for 24/48 h. Cell viability was determined by MTT assay. Protein levels of GPC3 and SULF2 were measured by ELISA at 24/48 h. GPC3 immunoreactivity was detected by immunocytochemistry. Moreover, GPC3 and SULF2 mRNA expressions in addition to lncRNA-AF085935 expression were assessed by qPCR at 48 h. The GPC3 protein, immunostaining and mRNA levels, SULF2 protein and mRNA levels, as well as lncRNA-AF085935 expression, were decreased significantly with cisplatin and chrysin alone when compared with the control untreated HepG2 cells. However, the combination treatment exhibited a better chemopreventive effect in a dose- and time-dependent manner. This study demonstrated, for the first time, the antiproliferative activity of chrysin against HCC through the suppression of the GPC3/SULF2 axis along with the downregulation of lncRNA-AF085935 expression. Synergistic effect of chrysin with cisplatin could potentiate their antiproliferative action in a dose- and time-dependent manner.

Screening and verification of long noncoding RNA promoter methylation sites in hepatocellular carcinoma

Background

Long noncoding ribonucleic acid (lncRNA) promoter methylation is closely related to the occurrence and development of hepatocellular carcinoma (HCC). Thus, we aim to screen and verify the lncRNA promoter methylation sites associated with overall survival (OS), vascular invasion, pathological grade, and clinical stage in HCC.

Methods

Methylation-related data including clinical characteristic, transcriptome, methylation, and messenger RNA (mRNA) expression were taken from the Cancer Genome Atlas (TCGA) database. The OS, vascular invasion, pathological grade, and clinical stage-related lncRNA promoter methylation models were developed by the least absolute shrinkage and selection operator (LASSO) algorithm based on the lncRNA promoter methylation sites screened via R software. The Kaplan-Meier analysis, the area under the receiver operating characteristic (ROC) curve (AUC), the calibration curve (C-index) were performed to evaluate the performance of these models. Finally, the methylation-specific polymerase chain reaction (MS-PCR) was performed to verify the accuracy of these models based on 146 HCC tissues from our hospital.

Results

A total of 10 methylation sites were included in the OS-related lncRNA promoter methylation model that could effectively divide HCC patients into high-risk and low-risk groups (P < 0.0001) via survival analysis. COX univariable and multivariable regression analysis found that the OS-related model (P < 0.001, 95% CI 1.378-2.942) and T stage (P < 0.001, 95% CI 1.490-3.418) were independent risk factors affecting OS in HCC patients. The vascular invasion-related model contained 8 methylation sites with its AUC value of 0.657; the pathological grade-related model contained 22 methylation sites with its AUC value of 0.797; the clinical stage-related model contained 13 methylation sites with its AUC of 0.724. Target genes corresponded to vascular invasion-related lncRNA promoter methylation sites were involved in many kinds of biological processes in HCC such as PI3K-Akt signaling pathway. The accuracy of the vascular invasion-related model was consistent with our bioinformatics conclusion after being verified via MS-PCR.

Conclusion

The lncRNA promoter methylation sites are closely correlated with the process of HCC and can be utilized to improve the therapy and prognosis of HCC.

A Circulating Long Noncoding RNA Panel Serves as a Diagnostic Marker for Hepatocellular Carcinoma

Background

Circulating long noncoding RNAs (lncRNAs) have been demonstrated to serve as diagnostic biomarkers for various cancers. We aimed to elucidate the diagnostic efficacy of eight serum lncRNAs HULC, MALAT1, Linc00152, PTENP1, PTTG3P, SPRY4-IT1, UBE2CP3, and UCA1 and their combinations for the diagnosis of hepatocellular carcinoma (HCC).

Methods

A total of 129 patients with HCC, 49 patients with liver cirrhosis, 27 patients with chronic hepatitis B, and 93 healthy controls were enrolled in this study. The levels of serum lncRNAs were assessed by quantitative real-time polymerase chain reaction. The correlations between serum lncRNAs and clinicopathological characteristics were further analyzed. The receiver operating characteristic (ROC) curve and area under curve (AUC) were utilized to estimate the diagnostic capacity of serum lncRNAs and their combination with AFP for HCC. A logistic regression model was performed to establish a multiple-lncRNA panel.

Results

The levels of serum HULC, MALAT1, Linc00152, PTTG3P, SPRY4-IT1, UBE2CP3, and UCA1 were significantly higher in HCC patients than in patients with benign liver diseases and healthy controls, whereas serum PTENP1 was significantly decreased in HCC patients compared with healthy participants. Positive correlations between serum Linc00152 and GGT, serum PTTG3P and GGT, and serum SPRY4-IT1 and ALT were noted in HCC patients. ROC analysis revealed that all these lncRNAs had a significantly predictive value for HCC except for PTENP1. The best performance of single lncRNA was obtained by Linc00152 with an AUC of 0.877. When combined with AFP, the combination of Linc00152 and AFP gained the highest accuracy, yielding an AUC of 0.906. Through logistic regression analysis, the panel consisting of serum linc00152, UCA1, and AFP provided the greatest predictive ability, obtaining an AUC of 0.912 with 82.9% sensitivity and 88.2% specificity.

Conclusion

The panel of serum Linc00152, UCA1, and AFP demonstrates a novel and noninvasive biomarker with relatively high sensitivity and specificity for HCC diagnosis.

Long non-coding RNA BCAR4 promotes liver cancer progression by regulating proliferation, migration and invasion

Liver cancer (LC) is one of the primary contributors of cancer-associated death worldwide. Long non-coding RNAs (lncRNAs) have been shown to participate in almost every aspect of cell biology and serve fundamental roles in carcinogenesis and cancer progression, including in LC. However, the clinical significance and functional role of the lncRNA breast cancer anti-estrogen resistance 4 (BCAR4) in LC have not yet been identified. The present study measured the expression levels of BCAR4 in LC cells and tissues, and discovered that BCAR4 was upregulated in LC tissues compared with adjacent normal tissues. Furthermore, high BCAR4 expression was associated with the presence of multiple tumors and advanced Tumor-Node-Metastasis stages (III/IV). Survival analysis found that high BCAR4 expression indicated poor overall survival (OS) and progression-free survival (PFS). By analyzing the risk factors of poor OS and PFS using univariate analysis and multivariate analysis, high BCAR4 expression was revealed to be an independent risk factor of poor prognosis. In addition, the role of BCAR4 was further investigated in vitro, which revealed overexpression of BCAR4 to markedly promote the proliferation, migration and invasion of LC cells. Conversely, the loss of BCAR4 expression repressed the proliferation, migration and invasion of LC cells. In conclusion, BCAR4 is overexpressed in LC and is associated with LC progression. Therefore, BCAR4 may be used as a potential prognostic marker in LC.

Dynamic Changes in Serum Markers and Their Utility in the Early Diagnosis of All Stages of Hepatitis B-Associated Hepatocellular Carcinoma

Objective

This study aimed to evaluate the individual and combined diagnostic values of serum alpha-fetoprotein (AFP), des-gamma-carboxyprothrombin (DCP), glypican-3 (GPC3) and golgi protein 73 (GP73) in diagnosing hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

Methods

Participants from Beijing YouAn Hospital were enrolled and divided into seven groups. Serum was collected and the levels of AFP, GPC3, GP73 and DCP were simultaneously measured with a protein array. Pearson's χ² test was applied to compare the clinicopathological characteristics. Receiver operating characteristic (ROC) curves were used to analyse the diagnostic performance of the four markers.

Results

As a single biomarker for differentiating HCC from all controls, AFP had a larger area under the curve (AUC) (0.798, 95% CI (0.754-0.838) than the other biomarkers, with a sensitivity of 77.3% and a specificity of 71.1%. Among the other combinations, AFP plus GPC3 and DCP (0.871, 95% CI (0.833-0.903)) was the best at differentiating HCC from all controls. In discriminating very early stage and early stage HCC from all controls, the AUC of GPC3 (0.744, 95% CI (0.690-0.793); sensitivity 62.8%; specificity 83.3%) was better than that of AFP (0.723, 95% CI (0.668-0.774); sensitivity 67.3%; specificity 71.7%). Among all biomarker combinations, the combination of AFP, GPC3 and GP73 had the largest AUC (0.843, 95% CI (0.796-0.883); sensitivity 84.1%; specificity 71.7%). AFP (AUC 0.726, 95% CI (0.662-0.784)) showed the best performance in the very early diagnosis of HBV-related HCC.

Conclusion

As a single biomarker, AFP has an advantage in the very early and early diagnosis of HBV-related HCC. The combination of AFP, GPC3 and GP73 is the most suitable marker for the early diagnosis of HBV-related HCC. However, AFP remains the best biomarker for the very early diagnosis of HBV-related HCC, and the adding of one or more markers does not significantly improve the diagnostic accuracy.

LINC00662 promotes hepatocellular carcinoma progression via altering genomic methylation profiles

The identification of viability-associated long noncoding RNAs (lncRNAs) is a means of uncovering therapeutic approaches for hepatocellular carcinoma (HCC). In addition, aberrant genome-wide hypomethylation has been implicated in HCC initiation and progression. However, the relationship between lncRNA dysregulation and genome-wide hypomethylation in hepatocarcinogenesis has not been fully elucidated. A novel lncRNA named LINC00662 was previously demonstrated to play a role in gastrointestinal cancer. In this study, we demonstrated that this lncRNA was correlated with survival and exhibited oncogenic properties, both in vitro and in vivo. Moreover, we determined that LINC00662 could lead to genome-wide hypomethylation and alter the genomic methylation profile by synchronously reducing the S-adenosylmethionine (SAM) level and enhancing the S-adenosylhomocysteine (SAH) level. Mechanistically, LINC00662 was determined to regulate the key enzymes influencing SAM and SAH levels, namely, methionine adenosyltransferase 1A (MAT1A) and S-adenosylhomocysteine hydrolase (AHCY), by RNA-RNA and RNA-protein interactions. In addition, we demonstrated that some SAM-dependent HCC-promoting genes could be regulated by LINC00662 by altering the methylation status of their promoters via the LINC00662-coupled axes of MAT1A/SAM and AHCY/SAH. Taken together, the results of this this study indicate that LINC00662 could be a potential biomarker for HCC therapy. More importantly, we proposed a new role of lncRNA in regulating genomic methylation to promote oncogene activation.

Elevated Expression of Cytosolic Phospholipase A2 Delta Is Associated with Lipid Metabolism Dysregulation during Hepatocellular Carcinoma Progression

Objective

Liver cancer is the third rank amongst the common malignancies, causing maximum death in the patients diagnosed with cancers. Currently available biomarkers are not enough sensitive for early diagnosis of hepatocellular carcinoma (HCC). This makes difficult management of HCC. With the aim of finding new generation of proteomic-based biomarkers, the represented study was designed to characterize the differentially expressed proteins at different stages of HCC initiation and at progression. This could lead to find potential biomarkers for early detection of HCC.

Materials and Methods

In this experimental study, we report induction of HCC by administrating chemical carcinogens in male Wistar rats. Disease progression was monitored by histological evaluation. Serum proteomic analyses such as 2 dimensional (2D)-electrophoresis, MALDI-TOF-MS/MS and Western blot have been used to analyze and characterize the differentially expressed proteins during HCC development.

Results

HCC initiation and tumorigenesis were observed at one and four months post carcinogen treatment, respectively. One of the differentially-expressed proteins, namely, cytosolic phospholipase A2delta was significantly up-regulated at very early stage of HCC development. Its expression continued to increase during cancer progression and hepatotumorigenesis stages. Its elevated expression has been confirmed by Western blot analysis. Consistent to this, analyses of the sera in the clinically confirmed liver cancer patients showed elevated expression of this protein, further validating our experimental results.

Conclusion

This study suggests that elevation in the expression of cytosolic phospholipase A2delta is associated with progression of HCC.

Expression of IL-26 predicts prognosis of patients with hepatocellular carcinoma after surgical resection

BACKGROUND

There is no data regarding prognostic impact of interleukin (IL)-26 on outcomes of patients with hepatocellular carcinoma (HCC). The present study aimed to evaluate the prognostic impact of IL-26 on HCC patients undergoing liver resection.

METHODS

From 2003 to 2008, 122 patients with HCC who received surgical curative resection were enrolled. Patients were stratified into IL-26-upper and -lower groups according to the median expression level from immunohistochemical staining of resected specimens. Prognostic impact of IL-26 was estimated using Kaplan-Meier curves. Univariate and multivariate analyses were performed to evaluate time-dependent prognostic impact and independency of IL-26. Demographic and clinical factors that were associated with IL-26 were comprehensively identified.

RESULTS

Prognosis of the patients with high level of IL-26 revealed to be significantly unfavorable in both cumulative recurrence-free survival (P < 0.001) and overall survival (P = 0.002). Upper expression of IL-26 (HR: 1.643; 95% CI: 1.021 to 2.644; P = 0.041) and microvascular invasion (HR: 3.303; 95% CI: 1.255 to 8.696; P = 0.016) were identified as significant independent prognostic factors for overall survival in the multivariable analysis.

CONCLUSIONS

IL-26 is a novel prognostic factor for HCC after resection. Evaluation of IL-26 expression may be potentially valuable in clinical therapy when planning individualized follow-up schedule and evaluating candidates for prophylactic adjuvant treatment to prevent recurrence.

Long non-coding SNHG1 in cancer

OBJECTIVES

Long non-coding RNAs (lncRNAs) consist of a cluster of RNAs having >200 nucleotides lacking protein-coding function. Recent studies indicate that lncRNAs are involved in various cellular processes and their aberrant expression may lead to tumour development and progression. They may also serve as oncogenes or tumour suppressor genes in other diseases. In this review, we emphasize current investigations involving clinical management, tumour progression and the molecular mechanism of SNHG1 in human cancer.

MATERIALS AND METHODS

We investigate and summarize recent studies regarding the biologic functions and mechanisms of lncRNA SNHG1 in tumorigenesis. Related studies were obtained through a systematic search of google scholar, PubMed, Embase and Cochrane Library.

RESULTS

SNHG1 is a novel oncogenic lncRNA aberrantly expressed in different diseases including colorectal, liver, lung, prostate, gastric and esophageal cancers as well as ischemic stroke, nasopharyngeal carcinoma, laryngeal squamous cell carcinoma, neuroblastoma, renal cell carcinoma and osteosarcoma. Upregulation of SNHG1 was significantly associated with advanced tumour stage, tumour size, TNM stage and decreased overall survival. Furthermore, aberrant expression of SNHG1 contributes to cell proliferation, metastasis, migration and invasion of cancer cells.

CONCLUSION

SNHG1 likely acts as a useful tumour biomarker for cancer diagnosis, prognosis and treatment.

Long noncoding RNAs in cancer cells

Long noncoding RNA (lncRNA) has recently been investigated as key modulators that regulate many biological processes in human cancers via diverse mechanisms. LncRNAs can interact with macromolecules such as DNA, RNA, or protein to exert cellular effects and to act as either tumor promoters or tumor suppressors in various malignancies. Moreover, the aberrant expression of lncRNAs may be detected in multiple cancer phenotypes by employing the rapidly developing modern gene chip technology and bioinformatics analysis. Herein, we highlight the mechanisms of action of lncRNAs, their functional cellular roles and their involvement in cancer progression. Finally, we provide an overview of recent progress in the lncRNA field and future potential for lncRNAs as cancer diagnostic markers and therapeutics.

NRAGE is a potential diagnostic biomarker of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of cancer-related deaths worldwide. Early diagnosis of HCC remains a great challenge in clinic. Novel and effective biomarkers are in urgent need in early diagnosis of HCC.Serum levels of neurotrophin-receptor-interacting melanoma antigen-encoding gene homolog (NRAGE) were measured for 107 patients with HCC, 98 patients with benign liver diseases, and 89 healthy controls using quantitative real-time polymerase chain reaction. Receiver operating characteristic curve was applied to evaluate the diagnostic capacity of serum NRAGE in HCC.NRAGE expression was significantly higher in patients with HCC than in controls (all, P < .05). Moreover, its expression was tightly correlated with TNM stage (P = .004). NRAGE could distinguish patients with HCC from healthy controls with the area under the curve (AUC) of 0.874, yielding a sensitivity of 81.3% and a specificity of 78.7%. Additionally, in differentiation between benign liver diseases and HCC, the AUC value of NRAGE was 0.726, with a sensitivity of 63.6% and a specificity of 73.5%. Meanwhile, alpha-fetoprotein also could distinguish patients with HCC from benign liver disease cases, with an AUC of 0.677, a sensitivity of 64.4%, and a specificity of 60.2%.NRAGE could be a potential biomarker for HCC early diagnosis.

Long non-coding RNAs: crucial regulators of gastrointestinal cancer cell proliferation

Studies of long non-coding RNAs (lncRNAs) have been prevalent in the field of non-coding RNA regulation in recent years. LncRNAs exert crucial effects on malignant cell processes in the gastrointestinal system, including proliferation. Aberrant lncRNA expression, through both oncogenes and tumor suppressor genes, is instrumental to tumor cell proliferation. Here, we summarize the different molecular mechanisms and relevant signaling pathways through which multifarious lncRNAs regulate cell proliferation and we show that lncRNAs are potential biomarkers for gastrointestinal cancers.

Long noncoding RNAs in the initiation, progression, and metastasis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Despite awareness of risk factors for the development of HCC and advances in the diagnosis and clinical management of the disease, the molecular mechanisms underlying hepatocarcinogenesis remain poorly understood. Recent experimental studies provide strong evidence that long noncoding RNAs (lncRNAs), non-protein-coding transcripts with lengths >200 basepairs, contribute to the pathogenesis of numerous human diseases. Over the past decade, a role for lncRNAs in the initiation, progression, and metastasis of HCC has likewise emerged and developed into a highly active area of research. Although many lncRNAs appear to be dysregulated in HCC, extensive functional characterization has been performed on only a small proportion of these candidates to date. This review summarizes select lncRNAs that have been shown to wield functional relevance in the initiation, progression, or metastasis of HCC, focusing on the specific mechanisms by which lncRNA effects might be linked to clinical manifestations of the disease. In addition, an overview of circulating lncRNAs that have been identified as potential biomarkers for the diagnosis and prognosis of HCC is provided.