Expression of microRNA 638 and sex-determining region Y-box 2 in hepatocellular carcinoma: Association between clinicopathological features and prognosis

MicroRNAs as Potential Diagnostic and Prognostic Biomarkers in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common cancer, and the second most common cause of cancer-associated death globally. One of the major reasons for this high rate of mortality is a failure to make an early diagnosis. The average survival in untreated HCC patients is estimated to be approximately three months. The 5-year overall survival rate after radical resection is about 15-40% and within two years, more than two third of patients experience a relapse. To date, the most common biomarker which has been used for the diagnosis of HCC is serum alpha-fetoprotein (AFP). However, there is a lack of sensitive and specific tumor biomarkers for the early diagnosis of HCC. MicroRNAs are a class of short endogenous RNA with crucial role in many biological activities and cellular pathways and can be found in various tissues and body fluids. The aim of this review was to summarize the results of recent studies investigating miRNAs as novel biomarkers for the early diagnosis and prognostic risk stratification of patients with this type of liver cancer.

Exosomal miR-638 Inhibits Hepatocellular Carcinoma Progression by Targeting SP1

Purpose

Exosomal microRNAs (miRNAs) play essential roles in the development of hepatocellular carcinoma (HCC). Nevertheless, the role and mechanism of exosomal miR-638 in HCC development remain largely unknown.

Methods

Exosomes were isolated and confirmed via transmission electron microscopy and western blot. The abundances of miR-638 and specificity protein 1 (SP1) were measured via quantitative reverse transcription polymerase chain reaction or western blot. Cell proliferation was investigated by Cell Counting Kit-8, colony formation assay, apoptosis, cell cycle distribution and related protein expression. Cell migration and invasion were detected via transwell assay and western blot. Co-culture experiment was performed to assess exosome transfer from HCC cells to endothelial cells. The target correlation between miR-638 and SP1 was analyzed via dual-luciferase reporter and RNA immunoprecipitation assays. The subcutaneous xenograft experiment was conducted to test the function of miR-638 in vivo.

Results

The miR-638 level declined in exosomes from serum or HCC cell medium. miR-638 overexpression repressed HCC cell proliferation by decreasing viability and colony formation and inducing apoptosis and cell cycle arrest at G1 phase, and decreased abilities of migration and invasion. Exosomal miR-638 from HCC cells could transfer to human umbilical vein endothelial cells (HUVECs) and suppress HUVEC proliferation, migration and invasion. SP1 was a target of miR-638 and overexpression of SP1 reversed the effect of miR-638 on HCC cells. Overexpression of miR-638 reduced xenograft tumor growth via decreasing SP1.

Conclusion

Exosomal miR-638 inhibited HCC tumorigenesis by targeting SP1. This study indicated the potential clinical implications of miR-638 in HCC.

Potential clinical value and putative biological function of miR-122-5p in hepatocellular carcinoma: A comprehensive study using microarray and RNA sequencing data

In order to determine the diagnostic efficacy of microRNA (miR)-122-5p and to identify the potential molecular signaling pathways underlying the function of miR-122-5p in hepatocellular carcinoma (HCC), the expression profiles of data collected from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and literature databases were analyzed, along with any associations between clinicopathological characteristics and the diagnostic value of miR-122-5p in HCC. The intersection of 12 online prediction databases and differentially expressed genes from TCGA and GEO were utilized in order to select the prospective target genes of miR-122-5p in HCC. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction network (PPI) analyses were subsequently performed based on the selected target genes. The average expression level of miR-122-5p was decreased in HCC patients compared with controls from TCGA database (P<0.001), and the downregulation of miR-122-5p was significantly associated with HCC tissues (P<0.001), tumor vascular invasion (P<0.001), metastasis (P=0.001), sex (P=0.006), virus infection status (P=0.001) and tissue (compared with serum; P<0.001) in cases from the GEO database. The pooled sensitivity and specificity for miR-122-5p to diagnose HCC were 0.60 [95% confidence interval (CI), 0.48–0.71] and 0.81 (95% CI, 0.70–0.89), respectively. The area under the curve (AUC) value was 0.76 (95% CI, 0.72–0.80), while in Meta-DiSc 1.4, the AUC was 0.76 (Q*=0.70). The pooled sensitivity and specificity were 0.60 (95% CI, 0.57–0.62) and 0.79 (95% CI, 0.76–0.81), respectively. A total of 198 overlapping genes were selected as the potential target genes of miR-122-5p, and 7 genes were defined as the hub genes from the PPI network. Cell division cycle 6 (CDC6), minichromosome maintenance complex component 4 (MCM4) and MCM8, which serve pivotal functions in the occurrence and development of HCC, were the most significant hub genes. The regulation of cell proliferation for cellular adhesion and the biosynthesis of amino acids was highlighted in the GO and KEGG pathway analyses. The downregulation of miR-122-5p in HCC demonstrated diagnostic value, worthy of further attention. Therefore, miR-122-5p may function as a tumor suppressor by modulating genome replication.