Sorafenib combined with dasatinib therapy inhibits cell viability, migration, and angiogenesis synergistically in hepatocellular carcinoma.

PURPOSE: Sorafenib is a multikinase inhibitor used for treatment of advanced hepatocellular carcinoma. Sorafenib resistance may be related to Src-induced cell migration and angiogenesis, which are regulated by cancer stem cell activation and release of vascular endothelial growth factor. Dasatinib is a Src inhibitor that inhibits Src phosphorylation and suppresses Src-associated cell migration and angiogenesis. This study investigated whether combined treatment with dasatinib can overcome sorafenib resistance. METHODS: Hepatoma cell lines were used for sorafenib and/or dasatinib treatment. Cell viability, cell migration, molecular expressions, and release of vascular endothelial growth factor by hepatoma cells were evaluated. Hepatoma cell culture medium was applied on human umbilical vein endothelial cells to monitor angiogenesis promoted by the hepatoma cells. RESULTS: Sorafenib and dasatinib combined therapy suppressed cell viability of hepatoma cells synergistically. Dasatinib suppressed sorafenib-induced cell migration via inhibiting sorafenib-induced Src/FAK phosphorylation, cell-to-cell contact and cancer stem cell activation. Culture medium from Chang liver and PLC/PRF/5 cells suppressed angiogenesis of human umbilical vein endothelial cells with any treatment, whereas sorafenib-treated medium of HepG2 cells induced angiogenesis. This sorafenib-induced angiogenesis was then suppressed by dasatinib. Vascular endothelial growth factor released from hepatoma cells was also inhibited by combined treatment. CONCLUSION: Src/FAK phosphorylation and cancer stem cell activation inducing cell migration and angiogenesis may be the key factors of sorafenib resistance. Sorafenib and dasatinib combined treatment suppresses cell migration and angiogenesis by inhibiting the Src/FAK phosphorylation, cell-to-cell contact, cancer stem cell activation, and release of vascular endothelial growth factor.

Plectin deficiency in liver cancer cells promotes cell migration and sensitivity to sorafenib treatment.

Plectin involved in activation of kinases in cell signaling pathway and plays important role in cell morphology and migration. Plectin knockdown promotes cell migration by activating focal adhesion kinase and Rac1-GTPase activity in liver cells. Sorafenib is a multi-targeting tyrosine kinase inhibitor that improves patient survival on hepatocellular carcinoma. The aim of this study is to investigate the correlation between the expression of plectin and cell migration as well as the sensitivity of hepatoma cell lines exposing to sorafenib. Hepatoma cell lines PLC/PRF/5 and HepG2 were used to examine the level of plectin expression and cell migration in comparison with Chang liver cell line. In addition, sensitivity of the 3 cell lines to sorafenib treatment was also measured. Expression of plectin was lower in PLC/PRF/5 and HepG2 hepatoma cells than that of Chang liver cells whereas HepG2 and PLC/PRF/5 cells exhibit higher rate of cell migration in trans-well migration assay. Immunohistofluorecent staining on E-cadherin revealed the highest rate of collective cell migration in HepG2 cells and the lowest was found in Chang liver cells. Likewise, HepG2 cell line was most sensitive to sorafenib treatment and Chang liver cells exhibited the least sensitivity. The drug sensitivity to sorafenib treatment showed inverse correlation with the expression of plectin. We suggest that plectin deficiency and increased E-cadherin in hepatoma cells were associated with higher rates of cell motility, collective cell migration as well as higher drug sensitivity to sorafenib treatment.

Photoradiation could influence the cytoskeleton organization and inhibit the survival of human hepatoma cells in vitro.

Low-power laser therapy has become popular in clinical applications including promoting wound healing and pain relief. However, effects of this photoradiation on human hepatoma cells are rarely studied. Previously, we found 808 nm gallium aluminum arsenide (GaAlAs) continuous wave laser had an inhibitory effect on the proliferation of human hepatoma cell lines HepG2 and J-5 at the energy density of 5.85 and 11.7 J/cm(2), respectively. The aim of the present study was to evaluate the possible mechanism of action of this photoradiation on HepG2 and J-5 cells. HepG2 and J-5 cells were cultured in 24-well plates for 24 h. After photoradiation by 130 mW 808 nm GaAlAs continuous wave laser for different time intervals (0, 30, 60, 90, 120, 150, and 180 s), Western blot and immunofluorescent staining were used to examine the expression and distribution of histone and cytoskeletal proteins. The cell counts as well as histone and synemin expression of HepG2 and J-5 cells were reduced by photoradiation at the energy density of 5.85 and 11.7 J/cm(2), respectively. Furthermore, the architecture of cytoskeletons and the distribution of intermediate filament-associated proteins (plectin and synemin) were disorganized by photoradiation. Photoradiation by 808 nm GaAlAs continuous wave laser at the energy density of 5.85 and 7.8 J/cm(2) inhibited the survival of human hepatoma cell lines. The mechanism might reduce synthesis of histone and synemin. Reduced histone synthesis might further reduce the proliferation rate of these cells. Reduced synemin synthesis might result in the destruction of the cytoskeleton. Therefore, the net effects by this photoradiation were reduced cell survival.

Effects of diode 808 nm GaAlAs low-power laser irradiation on inhibition of the proliferation of human hepatoma cells in vitro and their possible mechanism.

Low-power laser irradiation (LPLI) has come into a wide range of use in medical field. Considering basic research, LPLI can enhance DNA synthesis and increases proliferation rate of human cells. But only a few data about the effects of LPLI on human liver or hepatoma cells are available. The cytoskeleton plays important roles in cell function and therefore is implicated in the pathogenesis of many human liver diseases, including malignant tumors. In our previous study, we found the stability of cytokeratin molecules in human hepatocytes was related to the intact microtubule network that was influenced by colchicine. In this study, we are going to search the effect of LPLI on proliferation of human hepatoma cell line HepG2 and J-5 cells. In addition, the stability of cytokeratin and synemin (one of the intermediate filament-associated proteins) were analyzed under the action of LPLI to evaluate the possible mechanism of LPLI effects on proliferation of human hepatoma cells. In experiment, HepG2 and J-5 cells were cultured in 24-well plate for 24 hours. After irradiation by 130 mW diode 808 nm GaAlAs continue wave laser in different time intervals, the cell numbers were counted. Western blot and immunofluorescent staining examined the expression and distribution of PCNA, cytokeratin and synemin. The cell number counting and PCNA expression were evaluated to determine the proliferation. The organization and expression of cytokeratin and synemin were studied to identify the stability of cytoskeleton affected by LPLI. The results revealed that proliferation of HepG2 and J-5 cells was inhibited by LPLI since the cell number and PCNA expression was reduced. Maximal effect was achieved with 90 and 120 seconds of exposure time (of energy density 5.85 J/cm2 and 7.8 J/cm2, respectively) for HepG2 and J-5, respectively. The decreased ratio of cell number by this dose of irradiation was 72% and 66% in HepG2 and J-5 cells, respectively. Besides that, the architecture of intermediate filaments in these cells was disorganized by laser irradiation. The expression of intermediate filament-associated protein, synemin, was also reduced. Two significant findings are raised in this study: (1) Diode 808 nm GaAlAs continuous wave laser has an inhibitory effect on the proliferation of human hepatoma cells line HepG2 and J-5. (2) The mechanism of inhibition might be due to down-regulation of synemin expression and alteration of cytokeratin organization that was caused by laser irradiation.