Integrated Analysis of an lncRNA-Associated ceRNA Network Reveals Potential Biomarkers for Hepatocellular Carcinoma

The role of lnc‑MAPKAPK5‑AS1 in immune cell infiltration in hepatocellular carcinoma: Bioinformatics analysis and validation

The oncogenic and tumor suppressor roles of lnc-MAPKAPK5-AS1 in multiple cancers suggest its complexity in modulating cancer progression. The expression and promoter methylation level of lnc-MAPKAPK5-AS1 in hepatocellular carcinoma (HCC) was investigated through data mining from The Cancer Genome Atlas and Gene Expression Omnibus and its significance in prognosis and immunity was explored. lnc-MAPKAPK5-AS1 was co-expressed with its protein-coding gene MAPKAPK5 in HCC and exhibited upregulation in HCC tissues as a result of hypomethylation of its promoter region. High expression of lnc-MAPKAPK5-AS1 was associated with poor prognosis. Enrichment analysis revealed that lnc-MAPKAPK5-AS1 is involved in immune and metabolic-related pathways. Changes in the expression of lnc-MAPKAPK5-AS1 affected plasma cells, T cells CD4+ memory resting, NK cells, macrophages M0/M1, and mast cells resting in the tumor microenvironment. lnc-MAPKAPK5-AS1 was found to correlate with multiple immune checkpoints. Analysis of the Sangerbox database revealed positive relationships between expression of lnc-MAPKAPK5-AS1, tumor mutational burden and microsatellite instability, which suggested that immunotherapy may be effective in tumors with high expression of lnc-MAPKAPK5-AS1. The expression of lnc-MAPKAPK5-AS1 was verified to indicate sensitivity to 16 common targeted drugs. Immunohistochemistry confirmed the expression of MAPKAPK5 protein in HCC and its prognostic significance. Weighted gene co-expression network analysis was applied to identify hub genes related to both immunoreactive score and gene expression. These results revealed that lnc-MAPKAPK5-AS1 may be involved in the occurrence and development of HCC as an oncogene and may represent a potential therapeutic target through modulating the substance metabolism and immune response.

Recent updates of centromere proteins in hepatocellular carcinoma: a review

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related death worldwide, with approximately 800,000 deaths worldwide each year. Owing to the atypical early symptoms and characteristics of HCC, over 80% of HCC patients cannot receive curative treatment. The treatment of HCC is facing a bottleneck, and new treatment methods are urgently needed. Since the pathogenesis of HCC is not yet clear, identifying the molecular mechanisms and therapeutic targets related to it is crucial. Centromeres are considered special deoxyribonucleic acid (DNA) sequences with highly repetitive sequences that are physically connected to the spindle during cell division, ensuring equal division of genetic material between daughter cells. The numerous proteins that aggregate on this sequence during cell division are called centromere proteins (CENPs). Currently, numerous studies have shown that CENPs are abnormally expressed in tumor cells and are associated with patient prognosis. The abnormal expression of CENPs is a key cause of chromosomal instability. Furthermore, chromosomal instability is a common characteristic of the majority of tumors. Chromosomal instability can lead to uncontrolled and sustained division and proliferation of malignant tumors. Therapeutic plans targeting CENPs play important roles in the treatment of HCC. For example, small ribonucleic acid (RNA) can silence CENP expression and prevent the occurrence and development of liver cancer. In recent years, studies of HCC-targeting CENPs have gradually increased but are still relatively novel, requiring further systematic elaboration. In this review, we provide a detailed introduction to the characteristics of CENPs and discuss their roles in HCC. In addition, we discuss their application prospects in future clinical practice.

CAF-EVs carry lncRNA MAPKAPK5-AS1 into hepatocellular carcinoma cells and promote malignant cell proliferation

Hepatocellular carcinoma (HCC) is an aggressive malignancy with poor prognosis. LncRNA MAPKAPK5-AS1 is a potential oncogene and contributes to HCC cell malignant proliferation. This study explores the role of MAPKAPK5-AS1 carried by carcinoma-associated fibroblasts-derived extracellular vesicles (CAF-EVs) in HCC cell proliferation. Our findings reveal that CAF-EVs promotes HCC cell proliferation by delivering MAPKAPK5-AS1, which binds to and inhibits SMURF2 and stabilizes TCF12. SMURF2 leads to TCF12 ubiquitination and degradation. TCF12 upregulates FOXH1 expression. In animal model, CAF-EVs enhances tumor growth by stabilizing TCF12 via MAPKAPK5-AS1 and activating FOXH1 transcription. In conclusion, CAF-EVs carrying MAPKAPK5-AS1 stabilizes TCF12 expression by competitively inhibiting SMURF2, thus promoting TCF12-mediated FOXH1 transcription and driving HCC cell proliferation. Our findings may offer insights for HCC treatment and suggest potential targets for future treatments, opening avenues for HCC therapies.

Newcastle Disease Virus Manipulates Mitochondrial MTHFD2-Mediated Nucleotide Metabolism for Virus Replication

Viruses require host cell metabolic reprogramming to satisfy their replication demands; however, the mechanism by which the Newcastle disease virus (NDV) remodels nucleotide metabolism to support self-replication remains unknown. In this study, we demonstrate that NDV relies on the oxidative pentose phosphate pathway (oxPPP) and the folate-mediated one-carbon metabolic pathway to support replication. In concert with [1,2-13C2] glucose metabolic flow, NDV used oxPPP to promote pentose phosphate synthesis and to increase antioxidant NADPH production. Metabolic flux experiments using [2,3,3-2H] serine revealed that NDV increased one-carbon (1C) unit synthesis flux through the mitochondrial 1C pathway. Interestingly, methylenetetrahydrofolate dehydrogenase (MTHFD2) was upregulated as a compensatory mechanism for insufficient serine availability. Unexpectedly, direct knockdown of enzymes in the one-carbon metabolic pathway, except for cytosolic MTHFD1, significantly inhibited NDV replication. Specific complementation rescue experiments on small interfering RNA (siRNA)-mediated knockdown further revealed that only a knockdown of MTHFD2 strongly restrained NDV replication and was rescued by formate and extracellular nucleotides. These findings indicated that NDV replication relies on MTHFD2 to maintain nucleotide availability. Notably, nuclear MTHFD2 expression was increased during NDV infection and could represent a pathway by which NDV steals nucleotides from the nucleus. Collectively, these data reveal that NDV replication is regulated by the c-Myc-mediated 1C metabolic pathway and that the mechanism of nucleotide synthesis for viral replication is regulated by MTHFD2. IMPORTANCE Newcastle disease virus (NDV) is a dominant vector for vaccine and gene therapy that accommodates foreign genes well but can only infect mammalian cells that have undergone cancerous transformation. Understanding the remodeling of nucleotide metabolic pathways in host cells by NDV proliferation provides a new perspective for the precise use of NDV as a vector or in antiviral research. In this study, we demonstrated that NDV replication is strictly dependent on pathways involved in redox homeostasis in the nucleotide synthesis pathway, including the oxPPP and the mitochondrial one-carbon pathway. Further investigation revealed the potential involvement of NDV replication-dependent nucleotide availability in promoting MTHFD2 nuclear localization. Our findings highlight the differential dependence of NDV on enzymes for one-carbon metabolism, and the unique mechanism of action of MTHFD2 in viral replication, thereby providing a novel target for antiviral or oncolytic virus therapy.

High level of LncRNA MAPKAPK5-AS1 predicts poor prognosis and contributes to the malignant proliferation and EMT of non-small cell lung cancer via sponging miR-490-3p from HMGB2

BACKGROUND

Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD).

OBJECTIVE

To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC.

METHODS

The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model.

RESULTS

The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo.

CONCLUSION

Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.

Delineation of a SMARCA4-specific competing endogenous RNA network and its function in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignancy worldwide, and the mortality rate continues to rise each year. SMARCA4 expression has been associated with poor prognosis in various types of cancer; however, the specific mechanism of action of SMARCA4 in HCC needs to be fully elucidated.

AIM

To explore the specific mechanism of action of SMARCA4 in HCC.

METHODS

Herein, the expression level of SMARCA4 as well as its association with HCC prognosis were evaluated using transcriptome profiling and clinical data of 18 different types of cancer collected from The Cancer Genome Atlas database. Furthermore, SMARCA4-high and -low groups were identified. Thereafter, gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed to identify the function of SMARCA4, followed by construction of a SMARCA4-specific competing endogenous RNA (ceRNA) network using starBase database. The role of SMARCA4 in immunotherapy and its association with immune cells were assessed using correlation analysis.

RESULTS

It was observed that SMARCA4 was overexpressed and negatively correlated with prognosis in HCC. Further, SMARCA4 expression was positively associated with tumor mutational burden, microsatellite stability, and immunotherapy efficacy. The SNHG3/THUMP3-AS1-miR-139-5p-SMARCA4 ceRNA network was established and could be assumed to serve as a stimulatory mechanism in HCC.

CONCLUSION

The findings of this study demonstrated that SMARCA4 plays a significant role in progression and immune infiltration in HCC. Moreover, a ceRNA network was detected, which was found to be correlated with poor prognosis in HCC. The findings of this study could contribute towards the identification of predictive markers for immunotherapy and a novel mechanism of action for HCC treatment.

Construction of novel lncRNA-miRNA-mRNA ceRNA networks associated with prognosis of hepatitis C virus related hepatocellular carcinoma

Background

Hepatitis C virus (HCV) infection contribute to liver fibrosis and cirrhosis, which significantly increases the risk of hepatocellular carcinoma (HCC) development. Previous studies have demonstrated the pivotal role of competitive endogenous RNA (ceRNA) networks in tumorigenesis and cancer progression. Consequently, we herein seek to identify and evaluate the prognostic relevance of a novel ceRNA network associated with HCV-related HCC.

Methods

Differentially expressed genes (DEGs) in GSE140846 dataset from GEO were identified using Network Analyst, and GO, KEGG and Reactome analyses were performed. Furthermore, a protein-protein interaction network was generated, and hub genes were detected. Hub gene expression levels, as well as those of their upstream lncRNAs and miRNAs and associated survival analyses were conducted using appropriate bioinformatics databases. Predicted target relationships were used to establish putative ceRNA networks for HCV-related HCC.

Results

A total of 372 and 360 up- and down-regulated DE-mRNA were identified, which were associated with nuclear division, cell cycle, and ATPase activity. A PPI network containing 704 DE-mRNAs was constructed, and the 6 hub gene with the highest degree of connectivity were selected for subsequent analysis. We discovered that 22 miRNAs and 4 lncRNAs upstream of 11 hub gene were significantly associated with poor prognosis of HCV-related HCC, and used them to constructe a prognostic ceRNA network. Further experiments confirmed the ceRNA-regulatory relationship of BUB1-hsa-miR-193a-3p-MALAT1.

Conclusion

This study provides novel insights into the lncRNA-miRNA-mRNA ceRNA network, and reveals potential lncRNA biomarkers in HCV related HCC.

Estrogen Receptor-α Suppresses Liver Carcinogenesis and Establishes Sex-Specific Gene Expression

Estrogen protects females from hepatocellular carcinoma (HCC). To determine whether this protection is mediated by classic estrogen receptors, we tested HCC susceptibility in estrogen receptor-deficient mice. In contrast to a previous study, we found that diethylnitrosamine induces hepatocarcinogenesis to a significantly greater extent when females lack Esr1, which encodes Estrogen Receptor-α. Relative to wild-type littermates, Esr1 knockout females developed 9-fold more tumors. Deficiency of Esr2, which encodes Estrogen Receptor-β, did not affect liver carcinogenesis in females. Using microarrays and QPCR to examine estrogen receptor effects on hepatic gene expression patterns, we found that germline Esr1 deficiency resulted in the masculinization of gene expression in the female liver. Six of the most dysregulated genes have previously been implicated in HCC. In contrast, Esr1 deletion specifically in hepatocytes of Esr1 conditional null female mice (in which Cre was expressed from the albumin promoter) resulted in the maintenance of female-specific liver gene expression. Wild-type adult females lacking ovarian estrogen due to ovariectomy, which is known to make females susceptible to HCC, also maintained female-specific expression in the liver of females. These studies indicate that Esr1 mediates liver cancer risk, and its control of sex-specific liver gene expression involves cells other than hepatocytes.