MicroRNA-520c-3p inhibits hepatocellular carcinoma cell proliferation and invasion through induction of cell apoptosis by targeting glypican-3.

AIM: Glypican-3 (GPC3) is a membrane-associated heparan sulfate proteoglycan involved in regulation of cell proliferation, cell survival, cell migration and differentiation process. MicroRNAs (miRNAs) are single-stranded, non-coding functional RNAs that are important in many biological processes. GPC3 and miRNAs have been found to play essential roles in the development and progression of hepatocellular carcinoma (HCC). However, little information about the relationship between GPC3 and miRNAs is available nowadays. Therefore, this study aims to examine the relationship between GPC3 and miRNAs. METHODS: Dual-luciferase reporter assay was used to validate the direct target of GPC3. Fluorescence quantitative PCR and Western blotting were used to examined the gene expression at mRNA and protein levels. Cell apoptosis was evaluated by flow cytometric analysis and Annexin V-FITC staining. Invasion of cells was evaluated by Transwell matrigel assay. RESULTS: The results showed that miR-520c-3p could specifically target GPC3 in HCC cells. GPC3 protein levels decreased with unchanged transcription efficiency after miRNA transfection, and there was negative correlation of miR-520c-3p expression in HCC in relate to GPC3 protein levels. Moreover, miR-520c-3p not only induced HCC cell apoptosis, but also inhibited the growth and invasion of the cells. Interestingly, overexpression of GPC3 could effectively reverse apoptosis induced by miR-520c-3p transfection in HCC. CONCLUSIONS: Taken together, these results supported that miR-520c-3p may decrease GPC3 protein levels to inhibit proliferation of HCC cells. Therefore, GPC3 could be a new target for genetic diagnosis and treatment of HCC.

Knockdown of GPC3 inhibits the proliferation of Huh7 hepatocellular carcinoma cells through down-regulation of YAP.

Glypican-3 (GPC3), a membrane-associated heparan sulfate proteoglycan, is frequently upregulated in hepatocellular carcinoma (HCC). Yes-associated protein (YAP) is also found over-expressed in HCC and has been identified as a key effector molecule in Hippo pathway, which could control the organ size in animals through the regulation of cell proliferation and apoptosis and plays an important role in the development of malignant tumors. Studies have reported that GPC3 and YAP might collaborate to regulate the development of HCC. To elucidate the role of GPC3 in the development of HCC and its relationship with YAP, siRNA technique was employed to knock down GPC3 in Huh7 HCC cells. Moreover, recombinant human YAP-1 was used to examine the effects of GPC3 on Huh7 cells. The results of flow cytometric analysis and Annexin-V-FLUOS apoptosis assay showed that knockdown of GPC3-induced apoptosis in Huh7 cells, resulting in inhibition of cell proliferation as examined by EdU incorporation assay, migration, and invasion. GPC3 knockdown also suppressed the expression of YAP in mRNA and protein levels, as examined by fluorescence quantitative PCR and Western blot analysis. Moreover, addition of recombinant human YAP-1 effectively rescued the cells from apoptosis triggered by GPC3 knockdown. Taken together, our findings suggest that GPC3 regulates HCC cell proliferation with the involvement of Hippo pathway.

Dihydromyricetin inhibits migration and invasion of hepatoma cells through regulation of MMP-9 expression.

AIM: To investigate the effects of dihydromyricetin (DHM) on the migration and invasion of human hepatic cancer cells. METHODS: The hepatoma cell lines SK-Hep-1 and MHCC97L were used in this study. The cells were cultured in RPIM-1640 medium supplemented with 10% fetal bovine serum at 37 °C in a humidified 5% CO2 incubator. DHM was dissolved in dimethyl sulfoxide and diluted to various concentrations in medium before applying to cells. MTT assays were performed to measure the viability of the cells after DHM treatment. Wound healing and Boyden transwell assays were used to assess cancer cell motility. The invasive capacity of cancer cells was measured using Matrigel-coated transwell chambers. Matrix metalloproteinase (MMP)-2/9 activity was examined by fluorescence analysis. Western blot was carried out to analyze the expression of MMP-2, MMP-9, p-38, JNK, ERK1/2 and PKC-δ proteins. All data were analyzed by Student's t tests in GraphPad prism 5.0 software and are presented as mean ± SD. RESULTS: DHM was found to strongly inhibit the migration of the hepatoma cell lines SK-Hep-1 (without DHM, 24 h: 120 ± 8 µmol/L vs 100 µmol/L DHM, 24 h: 65 ± 10 µmol/L, P < 0.001) and MHCC97L (without DHM, 24 h: 126 ± 7 µmol/L vs 100 µmol/L DHM, 24 h: 74 ± 6 µmol/L, P < 0.001). The invasive capacity of the cells was reduced by DHM treatment (SK-Hep-1 cells without DHM, 24 h: 67 ± 4 µmol/L vs 100 µmol/L DHM, 24 h: 9 ± 3 µmol/L, P < 0.001; MHCC97L cells without DHM, 24 h: 117 ± 8 µmol/L vs 100 µmol/L DHM, 24 h: 45 ± 2 µmol/L, P < 0.001). MMP2/9 activity was also inhibited by DHM exposure (SK-Hep-1 cells without DHM, 24 h: 600 ± 26 µmol/L vs 100 µmol/L DHM, 24 h: 100 ± 6 µmol/L, P < 0.001; MHCC97L cells without DHM, 24 h: 504 ± 32 µmol/L vs 100 µmol/L DHM 24 h: 156 ± 10 µmol/L, P < 0.001). Western blot analysis showed that DHM decreased the expression level of MMP-9 but had little effect on MMP-2. Further investigation indicated that DHM markedly reduced the phosphorylation levels of p38, ERK1/2 and JNK in a concentration-dependent manner but had no impact on the total protein levels. In addition, PKC-δ protein, a key protein in the regulation of MMP family protein expression, was up-regulated with DHM treatment. CONCLUSION: These findings demonstrate that DHM inhibits the migration and invasion of hepatoma cells and may serve as a potential candidate agent for the prevention of HCC metastasis.