The role of circulating microRNA in hepatocellular carcinoma

MicroRNA-29a and MicroRNA-124 as novel biomarkers for hepatocellular carcinoma

BACKGROUND

Numerous microRNAs (miRNAs) have been observed to be abnormally expressed in cancer. Therefore, miRNA signatures could be potential noninvasive diagnostic and prognostic biomarkers for hepatocellular carcinoma (HCC).

AIMS

To correlate miRNA-29a and miRNA-124 expression levels with the clinical features and survival rates of HCC patients.

METHODS

Serum miRNA expression in 150 samples (50 patients with HCC, 50 patients with liver cirrhosis, and 50 healthy controls) were quantified using real-time qRT-PCR.

RESULTS

The expression levels of serum miRNA-29a were higher and the levels of miRNA-124 were lower in patients with HCC than in patients with liver cirrhosis and controls. ROC curve analysis showed promising accuracy for both miRNAs in distinguishing patients with HCC from those with liver cirrhosis. Levels of miRNA-29a were related to tumor number, size, stage, and outcome, whereas levels of miRNA-124 were related to vascular invasion. The overall survival rate of patients with low miRNA-29a expression was significantly higher than that of patients with high expression. Additionally, the multivariate analysis identified miRNA-29a as an independent prognostic variable.

CONCLUSIONS

The investigated miRNAs showed acceptable accuracy in the diagnosis of HCC; therefore, both could be utilized as diagnostic biomarkers. Additionally, miRNA-29a could be used as a prognostic biomarker.

Circ-PRMT5 enhances the proliferation, migration and glycolysis of hepatoma cells by targeting miR-188-5p/HK2 axis

INTRODUCTION AND OBJECTIVES

Circular RNA (circRNA) has been demonstrated as a critical regulator in human cancer, including hepatocellular carcinoma (HCC). Nevertheless, the role of circ-PRMT5 in HCC remains largely unknown.

PATIENTS OR MATERIALS AND METHODS

The real-time quantitative polymerase chain reaction (RT-qPCR) was performed to assess the expression levels of circ-PRMT5, miR-188-5p and anti-Hexokinase II (HK2) in HCC tissues and cells. The cell proliferation, migration and glycolysis were determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT), transwell migration assay, and indicated kits, respectively. The interaction relationship between miR-188-5p and circ-PRMT5 or HK2 was analyzed by the bioinformatics database, dual-luciferase reporter assay, and RNA immunoprecipitation (RIP) assay. The western blot assay was used to analyze the expression level of HK2. The functional role of circ-PRMT5 in vivo was assessed by a xenograft experiment.

RESULTS

Circ-PRMT5 was elevated in HCC tissues and cells than matched control groups. Furthermore, loss-of-functional experiments revealed that the silencing of circ-PRMT5 could repress proliferation, migration, glycolysis in vitro and tumor growth in vivo. Moreover, we also confirmed that overexpression of circ-PRMT5 abolished the effects on HCC cells induced by upregulating miR-188-5p. In addition, overexpression of miR-188-5p could repress the development of HCC. More importantly, HK2 was a target gene of miR-188-5p, and miR-188-5p regulated proliferation, migration, glycolysis of HCC cells by specifically binding to HK2. Mechanistically, circ-PRMT5 could act as a sponge of miR-188-5p to regulate the expression of HK2.

CONCLUSION

In summary, circ-PRMT5 might play a key role in proliferation, migration, glycolysis of HCC cells via miR-188-5p/HK2 axis, which indicated that circ-PRMT5 might be a potential therapeutic target for HCC treatment.

Circulating microRNA-1246 as a possible biomarker for early tumor recurrence of hepatocellular carcinoma

AIMS

Early tumor recurrence (ETR) after hepatic resection is a crucial predictor of poor prognosis in patients with hepatocellular carcinoma (HCC). The aim of this study was to identify clinically significant serum microRNAs (miRNAs) involved in the ETR of HCC.

METHODS

We compared expression profiles of circulating miRNAs from serum samples between five HCC patients with ETR (recurrence within 12 months after hepatectomy) and five HCC patients without recurrence using microarray analysis of miRNA. The identified miRNA associated with ETR was further verified in 121 HCC patients, 73 liver disease patients, and 15 health controls by real-time quantitative reverse transcription-polymerase chain reaction (PCR).

RESULTS

Of the approximately 2000 miRNAs analyzed, we identified 15 miRNAs for which expression levels correlated significantly with ETR. Of these miRNAs, we further investigated expression of miRNA-1246 (miR-1246). Quantitative PCR confirmed that miR-1246 was upregulated in HCC with ETR, compared to the level in HCC without ETR (P < 0.001). Serum miR-1246 showed a receiver operating characteristic curve area of 0.762, with 77.4% specificity and 54.1% sensitivity in discriminating HCC patients with ETR from HCC patients without ETR. Altered expression of miR-1246 was associated with aggressive tumor characteristics, including tumor-node-metastasis classification (P = 0.0413), tumor differentiation (P = 0.0419), and portal vein invasion (P = 0.0394). Moreover, multivariate Cox regression analysis identified serum miR-1246 level as an independent risk factor for overall survival (hazard ratio, 2.784; 95% confidence interval, 1.528-5.071; P = 0.0008).

CONCLUSION

Circulating miR-1246 in serum has strong potential as a novel ETR and prognostic biomarker for HCC.

MicroRNA 495 Inhibits Proliferation and Metastasis and Promotes Apoptosis by Targeting Twist1 in Gastric Cancer Cells

Recently, microRNAs (miRNAs) have been reported to participate in multiple biological processes. However, the effects of miR-495 on gastric cancer (GC) remain unclear. The purpose of this study was to explore the functions of miR-495 in GC cell proliferation, metastasis, and apoptosis. SGC-7901 and BGC-823 cell lines were transfected with miR-495 mimic, miR-495 inhibitor, and negative controls (mimic control and inhibitor control). The expressions of miR-495, cell viability, migration, apoptosis, and apoptosis-related factors were examined by qRT-PCR, trypan blue staining, Transwell, flow cytometry, and Western blot, respectively. Simultaneously, key factor expression levels of EMT were detected by qRT-PCR and Western blot. The direct target of miR-495 was confirmed by dual-luciferase assay. Additionally, sh-Twist1, pc-Twist1, and corresponding controls were transfected into SGC-7901 and BGC-823 cells, and the protein levels of EMT-associated factors were detected by Western blot. miR-495 was downregulated in GC cells. miR-495 expression level was effectively overexpressed or suppressed in SGC-7901 and BGC-823 cells. Overexpression of miR-495 significantly decreased cell viability and migration, increased apoptosis, and inhibited the EMT process. Suppression of miR-495 showed contrary results. Twist1 was clarified as a target gene of miR-495, and Twist1 silencing obviously reduced the promoting effect of miR-495 suppression on these biological processes. Twist1 silencing significantly blocked the EMT process in both SGC-7901 and BGC-823 cells. miR-495 inhibited proliferation and metastasis and promoted apoptosis by targeting Twist1 in GC cells. These data indicated that miR-495 might be a novel antitumor factor of GC and provide a new method for the treatment of GC.

MicroRNA-143 inhibits tumorigenesis in hepatocellular carcinoma by downregulating GATA6

MicroRNAs serve a critical role in human hepatocellular carcinoma (HCC) progression. However, the exact role of microRNA-143 (miR-143) in HCC remains unclear. The current study investigates the molecular mechanism of miR-143 in HCC. In cultured HepG2 and Bel7402 cell lines, miR-143 levels were raised by lentivirus transduction. This significantly inhibited HCC progression in terms of cell invasion and proliferation in both HepG2 and Bel7402 cell lines (P<0.05). MiR-143 also significantly decreased tumor implantation in vivo (P<0.05). Regulation of miR-143 on its direct target, GATA-binding factor 6 (GATA6), was investigated by multiple strategies, including dual-luciferase assay, quantitative polymerase chain reaction and western blot analysis. The results indicated that miR-143 was downregulated in both HCC cell lines and human tumors. GATA6 was identified as the downstream target of miR-143 in HCC, and overexpressing GATA6 was able to counter the tumor-suppressive effect of miR-143 on HCC in HepG2 and Bel7402 cells by significantly increasing proliferation and invasion rates (P<0.05). Therefore, a novel epigenetic pathway was identified in which miR-143 may suppress the malignancy of HCC by targeting GATA6.

MiR-199a-5p suppresses tumorigenesis by targeting clathrin heavy chain in hepatocellular carcinoma

The deregulation of microRNA (miRNA) is frequently associated with a variety of cancers, including hepatocellular carcinoma (HCC). In this study, we investigated the expression and possible role of miR-199a-5p in HCC. The expression of miR-199a-5p was measured by quantitative RT-PCR in HCC. The effect of miR-199a-5p was evaluated by cell viability and colony formation assays in HCC cell lines and tumor cell growth assay in xenograft nude mice. Quantitative real time PCR results showed that miR-199a-5p was down-regulated in 77.9 % (67/86) of HCC tissues compared with adjacent nontumor tissues. MiR-199a-5p mimic reduced cell viability and colony formation by induction of cell arrest in HCC cell lines and inhibited tumor cell growth in xenograft nude mice, but miR-199a-5p inhibitor increased cell viability and colony formation in HCC cell lines and tumor cell growth in xenograft nude mice. Furthermore, CLTC was defined as a potential direct target of miR-199a-5p by MiRanda and TargetScan predictions. The dual-luciferase reporter gene assay results showed that CLTC was a direct target of miR-199a-5p. The use of miR-199a-5p mimic or inhibitor could decrease or increase CLTC protein levels in HCC cell lines. We conclude that the frequently down-regulated miR-199a-5p can regulate CLTC and might function as a tumor suppressor in HCC. Therefore, miR-199a-5p may serve as a useful therapeutic agent for miRNA-based HCC therapy.

MicroRNA-542-3p inhibits the growth of hepatocellular carcinoma cells by targeting FZD7/Wnt signaling pathway

MicroRNAs (miRNA) are relevant regulators of the tumorigenesis of various cancers, such as hepatocellular carcinoma (HCC). Recent studies have suggested that miR-542-3p is a tumor suppressor gene in numerous cancers. However, the role of miR-542-3p in HCC remains unclear. This study showed that miR-542-3p was downregulated in HCC tissues and cell lines. MTT, colony formation, and cell cycle assays revealed that miR-542-3p overexpression inhibited HCC cell growth, whereas miR-542-3p suppression promoted cell growth. Frizzled7 (FZD7), the most important Wnt receptor involved in cancer development and progression, was identified as a functional target of miR-542-3p through dual-luciferase reporter assay, RT-qPCR, and Western blot. The mRNA expression of FZD7 was inversely correlated with miR-542-3p expression in HCC tissues. miR-542-3p overexpression could significantly decrease the activation of Wnt signaling pathway in HCC cells. FZD7 overexpression could significantly reverse the inhibitory effect of miR-542-3p on HCC cell growth and Wnt signaling pathway. Taken together, our study suggests that miR-542-3p inhibits HCC cell growth by targeting FZD7 and inhibiting Wnt signaling pathway. The decreased miR-542-3p expression may also contribute to the progression of HCC and may represent a novel molecular therapeutic target for HCC.

MicroRNA-1207-5p inhibits hepatocellular carcinoma cell growth and invasion through the fatty acid synthase-mediated Akt/mTOR signalling pathway

Fatty acid synthase (FASN) has emerged as a unique oncologic target for the treatment of cancers, including hepatocellular carcinoma (HCC). However, effective inhibitors of FASN for cancer treatment are lacking. MicroRNAs (miRNAs) have emerged as novel and endogenic inhibitors of gene expression. In the present study, we aimed to investigate the role of miR‑1207‑5p in HCC and the regulation of FASN through miR‑1207‑5p. The expression of miR-1207-5p was markedly reduced in HCC tissues and cell lines as detected with real‑time quantitative polymerase chain reaction (qPCR). Overexpression of miR-1207-5p significantly suppressed the cell growth and invasion of HCC cells. By contrast, inhibition of miR‑1207‑5p exhibited an opposite effect. Bioinformatics analysis showed that FASN is a predicted target of miR‑1207‑5p which was validated by dual‑luciferase reporter assay, qPCR and western blot analysis. Overexpression of miR‑1207‑5p inhibited the Akt/mTOR signalling pathway, and promotion of this pathway was noted following inhibition of miR‑1207‑5p. Rescue experiments showed that the restoration of FASN expression partially reversed the inhibitory effect of miR‑1207‑5p on cell growth, invasion and Akt phosphorylation. In conclusion, our study suggests that miR‑1207‑5p/FASN plays an important role in HCC, and provides novel insight into developing new inhibitors for FASN for therapeutic interventions for HCC.