[The mechanisms of inhibitory effect of adenovirus-mediated wild-type PTEN gene on the proliferation in activated hepatic stellate cells in vitro].

OBJECTIVE: Using an adenoviral vector, the wild-type PTEN gene was transduced into activated hepatic stellate cell (HSC) cultured in vitro and cell cycle markers and were detect. Thereby, the potential mechanisms of inhibitory effect of the wild-type PTEN overexpression on the proliferation in activated HSC was investigated. METHODS: The wild type PTEN gene was transduced into activated HSC (HSC-T6 ) cultured in vitro mediated by adenoviral vector. PTEN expression in HSC was measured by Western blot and Real-time fluorescent quantitation PCR. Flow cytometry (FCM) was then used to detect cell cycle phase of activated HSC. And the expressions of cyclinD1 and cyclin dependent kinase 4 (CDK4) in HSC were determined by Western blot. RESULTS: The data showed that exogenous wild type PTEN gene was successfully transduced and expressed in activated HSC cultured in vitro. The over-expression of wild type PTEN resulted in the increased number of HSC at G0/G1 phase ( P less than 0.01), and the number of HSC at S phase and G2/M phase were decreased significantly, P less than 0.01. Furthermore, there were decreased cyclinD1 and CDK4 expression in HSC infected with Ad-PTEN, P less than 0.01. CONCLUSION: The over-expression of wild type PTEN inhibit transition of activated HSC in vitro from G1 to S phase and arrest cell cycle of them at G0/G1 phase via the down-regulated expressions of cyclinD1 and CDK4, and then inhibit HSC proliferation.

[The influence of down-regulation of focal adhesion kinase by RNA interference on the adhesion and migration of rat hepatic stellate cells in vitro].

OBJECTIVE: To investigate the role of focal adhesion kinase (FAK) in adhesion and migration of hepatic stellate cells (HSC). METHODS: Two recombinant plasmids expressing short hairpin RNAs (shRNAs) targeting FAK were constructed and one plasmid substantially suppressing FAK expression in HSC was selected. Real-time PCR and Western blot were used to detect the knockdown effects of FAK gene. After 48-hour treatment with FAK shRNA, toluidine blue colorimetric assay was used to detect the cell adhesion. Wound-healing assay and improved Boyden double-chamber were used to detect the cell migration induced by FN. RESULTS: The recombinant plasmid expressing FAK shRNA was successfully constructed and transfected into HSC. Compared with the controls, the expression of FAK mRNA and protein in HSC treated with FAK shRNA was markedly down-regulated by 76.82% and 72.53%, respectively. The expression of p-FAK (Tyr397) protein was also decreased by 62.71% 48 h posttransfection. The adhesion of HSC was inhibited by 58.69% at 48 h after shRNA transfection. FAK gene silencing could also dramatically inhibit FN-stimulated HSC migration, and the cell migration distance and the cell number of crossing membrane were decreased by 58.27% and 83.70%, respectively. CONCLUSIONS: FAK gene silencing suppresses adhesion and migration of HSC, and FAK may be a potential target for novel anti-fibrosis therapies.

PTEN expression is down-regulated in liver tissues of rats with hepatic fibrosis induced by biliary stenosis.

The gene phosphatase and tensin homolog deleted on chromosome 10 (PTEN) codes for a tumor-suppressor phospholipid phosphatase. Deletion, mutation or abnormal expression of PTEN is commonly found in many kinds of malignant tumors. At the time of this study, though, the role of PTEN expression in the pathology of hepatic fibrosis remains unclear. In this study, we investigate the dynamic expression of PTEN in a rat model of hepatic fibrosis, with special emphasis on the activation and proliferation of hepatic stellate cells (HSC) in vivo. The rat model of hepatic fibrosis used in this study employed common bile duct ligation. At four time points, the expression of PTEN in hepatic tissues and activated HSC in rat liver tissues was measured by immunohistochemical staining, Western blotting, real-time fluorescent quantitative PCR and immunofluorescence confocal laser scanning microscopy, respectively. Further, alpha-smooth muscle actin (alpha-SMA), an activated HSC marker in rat liver tissues, was detected by immunohistochemical staining. This study showed that aggravation of hepatic fibrosis led to gradually decreasing expression of PTEN in the hepatic tissues. Further, as hepatic fibrosis worsens, PTEN-expressing activated HSC accounts for an increasingly smaller percentage of all activated HSC. In contrast, the percentage of alpha-SMA-expressing HSC cells increases significantly. In conclusion, expression of PTEN mRNA and protein is down-regulated in fibrogenic rat liver tissue, and its expression in HSC in vivo also decreases with progression of fibrosis. Thus, these results show that the dynamic expression of PTEN in hepatic tissues negatively correlates with activation and proliferation of HSC.

[The dynamic expression of PTEN in fibrogenic rat liver tissues and its relation to the activation and proliferation of hepatic stellate cells].

OBJECTIVE: To investigate the dynamic expression of PTEN in fibrogenic liver tissue of rats and its effect on the activation and proliferation of hepatic stellate cells (HSC). METHODS: A rat model of hepatic fibrosis was established by common bile duct ligation (BDL). The expressions of PTEN in the rat liver tissues were detected by immunohistochemical staining, Western blot and real-time PCR assay. The expressions of PTEN in activated HSC in the rat liver tissues were detected by immunofluorescence double labeling confocal laser scanning microscopy. The alpha-SMA in the rat liver tissues was determined by immunohistochemical staining. RESULTS: The immunohistochemical staining indicated that there was extensive expression of PTEN in the liver tissues of normal rats, it was expressed mainly in the cytoplasm of the HSC. With the aggravation of hepatic fibrosis, the expression of PTEN in the hepatic tissues decreased gradually (P less than 0.01), while the alpha-SMA positive cells in the hepatic tissues increased significantly (P less than 0.01). The expressions of PTEN protein and mRNA in the rat liver tissues at week 1, 2, 3 and 4 after BDL were all lower than those in the sham operation group (P less than 0.01), and the expressions gradually decreased with the development of hepatic fibrosis (P less than 0.01). Immunofluorescence double labeling confocal laser scanning microscopy showed that PTEN were expressed extensively in activated HSC, especially in the cytoplasm, and with the development of hepatic fibrosis, the PTEN-expressing activated HSC accounted for an increasingly smaller percentage of total activated HSC. CONCLUSION: The expressions of PTEN mRNA and protein in rat fibrogenic liver tissues were downregulated, and their expressions in HSC in vivo also decreased. The dynamic expressions of PTEN in liver tissues had a significant negative correlation with the activation and proliferation of HSC.