LINC00978 promotes hepatocellular carcinoma carcinogenesis partly via activating the MAPK/ERK pathway.

OBJECTIVE: To study the role of long non-coding RNA (lncRNA) LINC00978 in hepatocellular carcinoma (HCC) carcinogenesis. MATERIALS AND METHODS: LINC00978 expression level was measured by reverse transcription quantitative real-time PCR (RT-qPCR) in HCC tissues and adjacent healthy liver tissues from 49 HCC patients. MTT assay, colony forming assay, and flow cytometry were performed to evaluate the effects of shRNA-mediated LINC00978 knockdown on HCC cell proliferation, cell cycle progression, and apoptosis in vitro. Xenograft tumor model was performed to determine the effects of LINC00978 knockdown on HCC tumor growth in vivo. Western blot was used to assess the activation of signaling molecules in the apoptosis and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway. RESULTS: LINC00978 expression was significantly up-regulated in human HCC tissue relative to adjacent normal tissue, and LINC00978 high expression was correlated with poor HCC overall survival. LINC00978 was up-regulated in HCC cell lines. ShRNA-mediated LINC00978 knockdown significantly decreased HCC cell proliferation, and induced HCC cell cycle arrest and apoptosis in vitro. LINC00978 knockdown led to significant decrease in tumor xenograft size in vivo. Western blots revealed LINC00978 inhibition decreased ERK, p38, and c-Jun N-terminal kinase (JNK) phosphorylation in HCC cells. CONCLUSIONS: LINC00978 is highly expressed in human HCC tissue and correlates with poor HCC prognosis. LINC00978 promotes HCC cell proliferation, cell cycle progression, and survival, partially by activating the MAPK/ERK pathway. Our findings partially elucidated the roles of LINC00978 in HCC carcinogenesis, and identified a therapeutic target for HCC.

Inflammatory cytokine-induced expression of MASTL is involved in hepatocarcinogenesis by regulating cell cycle progression.

Microtubule associated serine/threonine kinase-like (MASTL) is the functional mammalian ortholog of Greatwall kinase (Gwl), which was originally discovered in Drosophila. Gwl is an essential kinase for accurate chromosome condensation and mitotic progression, and inhibits protein phosphatase 2A (PP2A), which subsequently dephosphorylates the substrates of cyclin B1-cyclin-dependent kinase 1, leading to mitotic exit. Previous studies have indicated that MASTL has a critical function in the regulation of mitosis in HeLa and U2OS cell lines, though there is currently limited evidence for the involvement of MASTL in hepatocarcinogenesis. The results of the present study revealed that MASTL was inducible by the proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α), which promoted the proliferation and mitotic entry of human liver cancer cells. It was also determined that MASTL was significantly overexpressed in cancerous liver tissues compared with non-tumor liver tissues. Mechanistically, stimulation by IL-6 and TNF-α induced the trimethylation of histone H3 lysine 4 (H3K4Me3) at the MASTL promoter to facilitate chromatin accessibility. Additionally, H3K4Me3 was associated with the activation of nuclear factor-κB, which subsequently upregulated MASTL expression. These findings suggested that MASTL may have pivotal functions in the development of hepatocarcinoma, and that it may be a potential target for treatment.

Screening the key genes of hepatocellular adenoma via microarray analysis of DNA expression and methylation profiles.

The aim of the present study was to identify the biomarkers involved in the development of hepatocellular adenoma (HCA) through integrated analysis of gene expression and methylation microarray. The microarray dataset GSE7473, containing HNF1α-mutated HCA and their corresponding non-tumor livers, 5 HNF1α-mutated HCA and 4 non-related non-tumor livers, was downloaded from the Gene Expression Omnibus (GEO) database. The DNA methylation profile GSE43091, consisting of 50 HCA and 4 normal liver tissues, was also downloaded from the GEO database. Differentially expressed genes (DEGs) were identified by the limma package of R. A t-test was conducted on the differentially methylated sites. Functional enrichment analysis of DEGs was performed through the Database for Annotation, Visualization and Integrated Analysis. The genes corresponding to the differentially methylated sites were obtained by the annotation files of methylation chip platform. A total of 182 DEGs and 3,902 differentially methylated sites were identified in HCA. In addition, 238 enriched GO terms, including organic acid metabolic process and carboxylic acid metabolic process, and 14 KEGG pathways, including chemical carcinogenesis, were identified. Furthermore, 12 DEGs were identified to contain differentially methylated sites, among which, 8 overlapped genes, including pregnancy zone protein and solute carrier family 22 member 1 (SLC22A1), exhibited inverse associations between gene expression levels and DNA methylation levels. The DNA methylation levels may be potential targets of HCA. The present study revealed that the 8 overlapped genes, including annexin A2, chitinase 3-like 1, fibroblast growth factor receptor 4, mal, T-cell differentiation protein like, palladin, cytoskeletal associated protein, plasmalemma vesicle associated protein and SLC22A1, may be potential therapeutic targets of HCA.

Long non-coding RNAs and genes contributing to the generation of cancer stem cells in hepatocellular carcinoma identified by RNA sequencing analysis.

Cancer stem cells (CSCs) play important roles in cancer initiation, progression and metastasis. The aim of the present study was to identify the potential targets that may contribute to the generation of hepatocellular carcinoma stem cells (HCSCs) from hepatocellular carcinoma (HCC) cells. The RNA sequencing (RNA­Seq) dataset GSE70537 was downloaded from the Gene Expression Omnibus (GEO) database. Raw RNA sequences were mapped to the GRCh37/hg19 genome based on TopHat and assembled through Cufflinks. Cuffdiff of Cufflinks was used for the screening of differentially expressed genes (DEGs) in the two types of HCSCs (Hep3B­C and Huh7­C) compared with the two types of HCC cells (Hep3B and Huh7) which were satisfied by the criteria of |log2(RPKMHCSC/RPKMHCC)| >1 and p<0.05. In addition, based on the Database for Annotation, Visualization, and Integrated Discovery (DAVID), we screened the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways which were enriched in the DEGs. For the DEGs with consistent differential expression in the two lists of DEGs, the LncRNA2Target database was used for the identification of long non­coding RNA (lncRNA)­gene pairs. A total of 218 and 591 DEGs were identified for the Hep3B­C and Huh7­C samples, respectively, and 22 overlaps were obtained. Biological processes and pathways related to steroid biosynthesis/metabolism or other substance transport were found to be enriched in the two lists of DEGs. Among the 22 overlaps, 16 were found to be consistently differentially expressed in the two HCSC samples, and the lncRNA­gene regulatory network of these genes was constructed. Moreover, several potential biomarkers that may play important roles in the transformation of HCSCs were identified in the regulation network. Through the bioinformatics analysis of the RNA­Seq dataset, several novel targets that were associated with the progression of HCC were obtained, and these targets may be valuable for the treatment and prognosis of HCC.

p53-induced microRNA-1246 inhibits the cell growth of human hepatocellular carcinoma cells by targeting NFIB.

In recent years, miR-1246 has been identified as a transcriptional target of p53 in Down syndrome and may provide a new p53-miR-1246-DYRK1A-NFAT pathway in cancer. The present study aimed to explore the role of miR-1246 in the tumorigenesis of human hepatocellular carcinoma (HCC). We found that wild-type p53 regulated the expression of miR-1246 in HCC cell lines, and alteration of miR-1246 modulated cell proliferation, colony formation ability and apoptosis. The nuclear factor I/B (NFIB), an oncogene, was identified as a direct target gene of miR-1246 using a fluorescent reporter assay. Overexpression of NFIB abolished the regulation of cell apoptosis caused by miR-1246 in HepG2 cells. This finding suggests that miR-1246 is regulated by p53 and suppresses the growth of human HCC by targeting NFIB. Here, we propose a new p53-miR-1246-NFIB pathway in HCC.