Sorafenib reverses multidrug resistance of hepatoma cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of sorafenib in reversing multidrug resistance (MDR) in hepatoma BEL-7402/FU cells and its possible mechanisms.</p><p><b>METHODS</b>MTT colorimetric assay was used to obtain the dose-response curve of sorafenib in BEL-7402/FU cells, and flow cytometry performed to assess the effect of sorafenib on Rho123 concentration in the cells. The optimal dose of sorafenib for cell treatment was determined according to the results of MTT assay and flow cytometry. MTT assay was employed to evaluate the effect of sorfenib on the cytotoxicity of the antitumor drugs, flow cytometry performed to determine the expression of cell membrane transport protein (P-gp), and RT-PCR used to detect mdr1 gene expression in the cells treated with sorafenib at the optimal dose.</p><p><b>RESULTS</b>Sorafenib at the concentration of 4 micromol/L, efficiently reversed the MDR of the cells with minimal side effects. At the concentration of 4 micromol/L, sorafenib partially reversed the drug resistance of BEL-7402/FU cells to ADM, 5-FU, GEM and DDP, with reversal indexes of 2.98, 7.16, 1.99 and 10.08, respectively. Treatment of the cells with 4 micromol/L, sorafenib also partially down-regulated P-gp expression in BEL-7402/FU cells, and caused a reduction of mdr1 gene expression by 27.3% in comparison with the control cells.</p><p><b>CONCLUSION</b>Sorafenib can reverse MDR in human hepatoma cells probably in association with down-regulation of mdr1 gene expression and increased accumulation of the chemotherapeutic agents in the cells.</p>

Inhibitory effect of sorafenib combined with arsenic trioxide on hepatocellular carcinoma cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of sorafenib in combination with arsenic trioxide (As2O3) on hepatocellular carcinoma cells and explore the mechanisms of the synergetic antitumor effects of the two agents.</p><p><b>METHODS</b>HepG2 cells were treated with sorafenibor, As2O3 alone or their combination, with the untreated cells used as the control. The inhibitory effect of the treatment was analyzed by MTT assay, and the cell apoptosis and mitochondrial transmembrane potential (delta phi m) were detected by flow cytometry. Western blotting was performed to examine the expressions of ERK and pERK in the cells.</p><p><b>RESULTS</b>Sorafenib and As2O3 used alone or in combination both inhibited the proliferation of HepG2 cells, and a synergistic effect of the two agents was noted in their combined action (P<0.05). Combined treatment of the cells resulted in significantly higher apoptsis rate than that in the other groups (P<0.05), and was associated with a more obvious decrease in delta phi m. The expression of ERK was not affected by the two agents used either alone or in combination, but pERK expression was significantly lowered in the cells after combined treatment for 24 h.</p><p><b>CONCLUSION</b>A synergistic effect is observed between the sorafenib and As2O3 in their inhibition of HepG2 cell proliferation, the mechanisms of which may involve reduction of mitochondrial transmembrane potential and Raf/MEK/ERK pathway inhibition.</p>

Coadministration of sorafenib and cisplatin inhibits proliferation of hepatocellular carcinoma HepG2 cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of sorafenib in combination with cisplatin (DDP) on the proliferation of hepatocellular carcinoma cells and explore the molecular mechanisms.</p><p><b>METHODS</b>The inhibitory effect of sorafenib and DDP treatment on HepG2 cell proliferation in vitro was assessed by MTT assay. The cell cycle changes and the apoptotic rate of the treated cells were detected by flow cytometry, and the expressions of ERK and pERK examined using Western blotting.</p><p><b>RESULTS</b>Sorafenib and DDP alone both significantly inhibited the proliferation of HepG2 cells, showing a synergistic effect of their actions in combined use (P<0.05). Sorafenib and DDP alone caused cell cycle arrest at G(1) and G(2) phases, respectively. Combined use of the two drugs resulted in significant reduction of the S-phase cell percentage and cell cycle arrest at G(1) and G(2) phases. The coadministration of the drugs significantly increased the apoptosis rate of the cells as compared with the that of the cells with sorafenib or DDP treatment alone (P<0.05). Sorafenib and DDP, used alone or in combination, did not produce obvious effect on ERK expression. Sorafenib treatment for 24 h reduced pERK expression in the HepG2 cells, and the effect was enhanced by combined treatment with sorafenib and DDP.</p><p><b>CONCLUSIONS</b>Sorafenib and DDP show a synergistic effect in inhibiting the proliferation and inducing apoptosis of HepG2 cells. The mechanisms of this synergistic effect can be closely related to the double blockage of the cell cycle and Raf/MEK/ERK pathway inhibition.</p>

Establishment of an rat model of tumor-associated depression / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish an animal model of tumor-associated depression and observe their biological behaviors and biochemical indices.</p><p><b>METHODS</b>Four groups of SD rats kept in separate cages were subjected to tumor cell inoculation with or without chronic unpredictable moderate stress administered before or after the inoculation. The depressive behaviors of the rats were examined by open-field test, and the concentration of 5-HT in the hippocampus was measured by spectrophotofluorometry. The body weight of the rats and volume of the implanted tumor were monitored and sugar water test was performed.</p><p><b>RESULTS</b>The rats subjected to chronic stress displayed significant depression, manifested by reduction in movement in the central area and total movement distance with prolonged resting time and shortened time of activity. These rats maintained high levels of depression even 12 days after withdrawal of chronic stress. Compared with the control group, the depressive rats showed obviously reduced sugar water consumption and hippocampal 5-HT level. Tumors of different sizes were observed in all rats in the 4 groups.</p><p><b>CONCLUSION</b>A rat model of tumor-associated depression is established, and the tumor-bearing rats exhibit obvious depressive behaviors and reduced level of neural substance (5-HT), which provides a good basis for studying the association of depression with tumorigenesis,progression and prognosis of tumor.</p>