Xiao-Hui Huang

Involvement of PI3K/PTEN/AKT/mTOR pathway in invasion and metastasis in hepatocellular carcinoma: Association with MMP‐9

Aim:  To investigate the status of Phosphatidylinositol 3‐kinase (PI3K)/PTEN/AKT/mammalian target of rapamycin (mTOR) pathway and its correlation with clinicopathological features and matrix metalloproteinase‐2, ‐9 (MMP‐2, 9) in human hepatocellular carcinoma (HCC).

Bead‐based microarray analysis of microRNA expression in hepatocellular carcinoma: miR‐338 is downregulated

Aim:  Recent studies have underlined causative links between microRNA (miRNA) deregulation and cancer development. However, the relevance of abnormally expressed miRNA to tumor biology has not been well understood in hepatocellular carcinoma (HCC).

Sonic hedgehog signaling pathway induces cell migration and invasion through focal adhesion kinase/AKT signaling-mediated activation of matrix metalloproteinase (MMP)-2 and MMP-9 in liver cancer

The aberrant activation of sonic hedgehog (SHH) pathway contributes to initiation and progression of various malignancies. However, the roles and underlying mechanisms of SHH signaling pathway in invasion and metastasis of liver cancer have not been well understood. In this study, we found that SHH signaling was activated and correlated with invasion and metastasis in hepatocellular carcinoma (HCC). Enhanced SHH signaling by recombinant human SHH N-terminal peptide (rSHH-N) promoted hepatoma cell adhesion, migration and invasion, whereas blockade of SHH signaling with SHH neutralizing antibody or cyclopamine suppressed hepatoma cell adhesion, migration and invasion. Furthermore, matrix metalloproteinase (MMP)-2 and MMP-9 expressions and activities were upregulated and downregulated by rSHH-N and SHH signaling inhibitor, respectively. The rSHH-N-mediated hepatoma cell migration and invasion was blocked by MMP-specific inhibitors or neutralizing antibodies to MMP-2 and MMP-9. In addition, phosphorylations of AKT and focal adhesion kinase (FAK) were increased and decreased by rSHH-N and SHH signaling inhibitor, respectively. Further investigations showed that activation of AKT and FAK were required for rSHH-N-mediated upregulation of MMP-2 and MMP-9, cell migration and invasion. Finally, we found that SHH protein expression was positively correlated with phosphorylatd FAK Tyr397, phosphorylatd AKT Ser473, MMP-2 and MMP-9 protein expressions in HCC samples. Taken together, our findings suggest that SHH pathway induces cell migration and invasion through FAK/AKT signaling-mediated MMP-2 and MMP-9 production and activation in liver cancer.

miR-338-3p suppresses invasion of liver cancer cell by targeting smoothened†

MicroRNAs are involved in human carcinogenesis and cancer progression. Our previous study has shown that loss of miR‐338‐3p expression is associated with clinical aggressiveness of hepatocellular carcinoma (HCC). However, the exact roles and mechanisms of miR‐338‐3p remain unknown in HCC. To determine whether and how miR‐338‐3p influences liver cancer cell invasion, we studied miR‐338‐3p in the liver cancer cell lines, and we found that miR‐338‐3p is down‐regulated in treated cells. Forced expression of miR‐338‐3p in SK‐HEP‐1 cells suppressed cell migration and invasion, whereas inhibition of miR‐338‐3p in SMMC‐7721 cells induced cell migration and invasion. Furthermore, smoothened (SMO) was identified as a direct target of miR‐338‐3p. Forced expression of miR‐338‐3p down‐regulated SMO and matrix metalloproteinase (MMP)‐9 expression, but inhibition of miR‐338‐3p up‐regulated SMO and MMP9 expression. However, small interfering RNA targeted SMO reversed the effects induced by blockade of miR‐338‐3p. SMO and MMP9 were overexpressed and associated with invasion and metastasis in HCC tissues. These data indicate that miR‐338‐3p suppresses cell invasion by targeting the smoothened gene in liver cancer in vitro and miR‐338‐3p might be a novel potential strategy for liver cancer treatment. Copyright

FAK is involved in invasion and metastasis of hepatocellular carcinoma

Studies have shown that focal adhesion kinase (FAK) is overexpressed in several human tumors and plays an important role in tumor progression. However, the role and underlying mechanisms of FAK in hepatocellular carcinoma (HCC) progression remains to be elucidated. In this study, we examined FAK and phosphorylated FAK Tyr397 expression in a large series of HCCs. We found that both FAK and phosphorylated FAK Tyr397 were overexpressed in HCC samples and HCC cell lines. Increased FAK and phosphorylated FAK Tyr397 expressions were correlated with tumor stage, vascular invasion and intrahepatic metastasis in HCC. Furthermore, HCC cell adhesion, migration and invasion were substantially impaired by siRNA-mediated knockdown of FAK expression, whereas cell growth, apoptosis and cell cycle distribution were not affected. In addition, depletion of FAK induced a significant reduction in expressions and activities of both MMP-2 and MMP-9. Taken together, FAK contributes to invasion and metastasis of HCC partly through regulating expressions and activations of both MMP-2 and MMP-9, suggesting FAK could be a promising therapeutic target for HCC.

PPAR gamma inhibits growth of rat hepatic stellate cells and TGF beta-induced connective tissue growth factor expression

AbstractAim:To investigate the effect of peroxisome proliferator-activated receptor gamma (PPARγ) activation on the growth of rat hepatic stellate cells (HSC) and transforming growth factor beta (TGF-β)-induced connective tissue growth factor (CTGF) expression.Methods:After being treated with various amounts of the PPARγ natural ligand 15-deoxy-Δ12,14-prostaglandin J2 (15-d-PGJ2) or synthetic ligand GW7845, the status of HSC proliferation and apoptosis were detected by MTT assay and flow cytometry. Furthermore, HSC were treated with PPARγ-specific antagonist GW9662 prior to the addition of 15-d-PGJ2 or GW7845 and were subsequently stimulated with TGF-β1. The mRNA and protein levels of CTGF expression were detected by semi-quantitative RT-PCR and Western blotting analysis. Morphological changes in the HSC were observed by electron microscopy.Results:15-d-PGJ2 and GW7845 markedly inhibited HSC proliferation and induced cell apoptosis in a dose-dependent manner. Furthermore, PPARγ ligands significantly suppressed TGF-β1-induced CTGF expression (at both transcriptional and post-transcriptional levels) in HSC, and the inhibitory effect was dramatically, if not completely, abolished by pretreatment with GW9662, suggesting that the inhibition was indeed mediated by PPARγ. Moreover, morphological observation revealed that PPARγ activation caused obvious changes of HSC from activated to quiescent phenotype.Conclusion:The PPARγ ligand has a potent inhibitory effect on the growth of HSC and TGF-β1-induced CTGF expression, which makes it a potential antifibrotic candidate for the treatment and prevention of hepatic fibrosis.

Clinical significance of miR-221 and its inverse correlation with p27Kip1 in hepatocellular carcinoma

The aim of the present study is to explore possible role of miR-221 in the pathogenesis of HCC. Matched HCC and adjacent non-cancerous samples were assayed for the expression of miR-221 and three G1/S transition inhibitors: p27Kip1, p21WAF1/Cip1and TGF-β1 by in situ hybridization and immunohistochemistry respectively. p27Kip1 is one of miR-221’s proven targets. Real time qRT-PCR was used to investigate miR-221 and p27Kip1 transcripts in different clinical stages. Western blotting was used to analyze the expression levels of p27Kip1 protein in different clinical stages. In result, miR-221 and TGF-β1 are frequently up-regulated in HCC, while p27Kip1 and p21WAF1/Cip1 proteins are frequently down-regulated. Moreover, miR-221 and p27Kip1’s expression correlated with metastasis and miR-221’s expression also correlated with tumor size. Both of p21WAF1/Cip1and TGF-β1’s expression correlated with tumor differentiations. miR-221’s upregulation and p27Kip1’s downregulation were significantly associated with tumor stages and metastasis. In conclusion, miR-221 is important in tumorigenesis of HCC, possibly by specifically down-regulating p27Kip1, a cell-cycle inhibitor. These results indicate miR-221 as a new therapeutic target in HCC.

Upregulation of PTEN involved in rosiglitazone-induced apoptosis in human hepatocellular carcinoma cells.

AbstractAim:To investigate the effects of rosiglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, on the expression of the phosphatase and tensin homologue deleted on chromosome 10 gene (PTEN) and cell growth in hepatocellular carcinoma cells, as well as the underlying mechanisms of these effects.Methods:RT-PCR and Western blotting analyses were performed to detect transcription and the expression of PTEN in Hep3B cells treated with rosiglitazone. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to evaluate cell growth. Flow cytometry, DNA fragmentation analysis, caspase enzymatic assay, and Hoechst 33258 staining were used to determine cell apoptosis. Furthermore, small interfering RNA was used to suppress PTEN expression.Results:Rosiglitazone increased the expression of PTEN in a dose-and time-dependent manner through the PPARγ-dependent signal transduction pathway. PTEN upregulation was concomitant with a decreased level of Akt phosphorylation, subsequently resulting in cell growth inhibition and apoptosis in Hep3B cells. PTEN knockdown dramatically blocked these effects of rosiglitazone. Moreover, the exposure of cells to rosiglitazone activated caspases-9 and -3 during apoptotic proceeding.Conclusion:Thus, upregulation of PTEN is involved in the inhibition of cell growth and the induction of cell apoptosis by rosiglitazone, suggesting that rosiglitazone may be useful in liver cancer therapy via apoptosis.

Green tea polyphenol epigallocatechin-3-gallate suppresses rat hepatic stellate cell invasion by inhibition of MMP-2 expression and its activation

AbstractAim:Epigallocatechin-3-gallate (EGCG) is the major component of green tea polyphenols, whose wide range of biological properties includes anti-fibrogenic activity. Matrix metalloproteinases (MMP) that participate in extracellular matrix degradation are involved in the development of hepatic fibrosis. The present study investigates whether EGCG inhibits activation of the major gelatinase matrix metalloproteinase-2 (MMP-2) in rat hepatic stellate cells (HSC).Methods:The expression of MMP-2, tissue inhibitors of metalloproteinases-2 (TIMP-2), and membrane-type 1-MMP (MT1-MMP) was assessed by RT-PCR and Western blot analyses. MMP-2 activity was evaluated by zymography and MT1-MMP activity was assessed by an enzymatic assay. HSC migration was measured by a wound healing assay and cell invasion was performed using Transwell cell culture chambers.Results:The expression of MMP-2 mRNA and protein in HSC was substantially reduced by EGCG treatment. EGCG treatment also reduced con-canavalin A (ConA)-induced activation of secreted MMP-2 and reduced MT1-MMP activity in a dose-dependent manner. In addition, EGCG inhibited either HSC migration or invasion.Conclusion:The abilities of EGCG to suppress MMP-2 activation and HSC invasiveness suggest that EGCG may be useful in the treatment and prevention of hepatic fibrosis.

Downregulation of LncRNAH19 and MiR-675 promotes migration and invasion of human hepatocellular carcinoma cells through AKT/GSK-3β/Cdc25A signaling pathway

SummaryLncRNAH19 has been implicated as having both oncogenic and tumor suppression properties in cancer. LncRNAH19 transcripts also serve as a precursor for miR-675. However, it is unknown whether LncRNAH19 and miR-675 are involved in the migration and invasion of hepatocellular carcinoma (HCC) cells. The purpose of this study was to investigate the effect and mechanism of LncRNAH19 and miR-675 on migration and invasion of HCC cells. The migration and invasion of HCC cells were measured by Transwell migration and invasion assays after transfection of HCC cells with miR-675 inhibitors and LncRNAH19siRNA. The levels of LncRNAH19 and miR-675 were detected by quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR), and the protein expression of AKT, GSK-3β and Cdc25A by Western blotting analysis. The expression levels of LncRNAH19 and miR-675 were higher in MHCC-97H cells than in L02, Huh-7 and HepG2 cells. Transwell migration assay revealed that the miR-675 inhibitor and LncRNAH19siRNA could significantly increase the migration of HCC cells (P<0.01) as compared with the control group. Transwell invasion assay demonstrated that the miR-675 inhibitor and LncRNAH19siRNA could significantly increase the invasion of HCC cells (P<0.01) as compared with the control group. Western blotting analysis showed that the expression levels of AKT and Cdc25A were significantly increased (P<0.05), and the expression level of GSK-3β was significantly decreased (P<0.05) after treatment with miR-675 inhibitors and LncRNAH19siRNA as compared with the control group. These findings suggested that inhibition of LncRNAH19 and miR-675 expression can promote migration and invasion of HCC cells via AKT/GSK-3β/Cdc25A signaling pathway.LncRNAH19 has been implicated as having both oncogenic and tumor suppression properties in cancer. LncRNAH19 transcripts also serve as a precursor for miR-675. However, it is unknown whether LncRNAH19 and miR-675 are involved in the migration and invasion of hepatocellular carcinoma (HCC) cells. The purpose of this study was to investigate the effect and mechanism of LncRNAH19 and miR-675 on migration and invasion of HCC cells. The migration and invasion of HCC cells were measured by Transwell migration and invasion assays after transfection of HCC cells with miR-675 inhibitors and LncRNAH19siRNA. The levels of LncRNAH19 and miR-675 were detected by quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR), and the protein expression of AKT, GSK-3β and Cdc25A by Western blotting analysis. The expression levels of LncRNAH19 and miR-675 were higher in MHCC-97H cells than in L02, Huh-7 and HepG2 cells. Transwell migration assay revealed that the miR-675 inhibitor and LncRNAH19siRNA could significantly increase the migration of HCC cells (P<0.01) as compared with the control group. Transwell invasion assay demonstrated that the miR-675 inhibitor and LncRNAH19siRNA could significantly increase the invasion of HCC cells (P<0.01) as compared with the control group. Western blotting analysis showed that the expression levels of AKT and Cdc25A were significantly increased (P<0.05), and the expression level of GSK-3β was significantly decreased (P<0.05) after treatment with miR-675 inhibitors and LncRNAH19siRNA as compared with the control group. These findings suggested that inhibition of LncRNAH19 and miR-675 expression can promote migration and invasion of HCC cells via AKT/GSK-3β/Cdc25A signaling pathway.