Tetrandrine inhibits glioma stem-like cells by repressing ß-catenin expression.

Cancer stem cells (CSCs) in glioma are often responsible for relapse and resistance to therapy. The purpose of the present study was to confirm the self-renewal and migration inhibitory effects of tetrandrine (Tet), which is a compound extracted from the dried root of Stephania tetrandra S. Moore, toward glioma stem-like cells (GSLCs) and to examine the associated molecular mechanisms. Using a neurosphere culture technique, we enriched the GSLC population from the human glioblastoma cell lines U87 and U251. Cells were analyzed using cell counting kit-8 (CCK-8), western blotting, flow cytometry, transwell assay and immunofluorescence staining. GSLCs displayed properties of neural stem cells, including elevated expression of the cancer stem cell marker ALDH1 and ß-catenin. We found that Tet treatment decreased sphere formation in GSLCs in a dose-dependent manner using tumor spheroid formation assay. The GSK3ß inhibitor BIO maintained sphere formation and migration capacity in GSLCs, whereas the ß-catenin/TCF transcription inhibitor ICG-001 decreased sphere formation and the migration capacity of GSLCs. The proportion of apoptotic GSLCs also increased in response to ICG-001 treatment. These results indicate that ß-catenin activity is vital in maintaining neural stem cell traits of GSLCs. Tet inhibits cell viability, neurosphere formation and migration of GSLCs in vitro. Importantly, Tet treatment significantly repressed the nuclear translocation and expression of ß-catenin and induced apoptosis in GSLCs, as indicated in part by the upregulation of Bax, the cleavage of PARP and the downregulation of Bcl-2. The present study demonstrates that the inhibition of ß-catenin in CSCs by Tet could be an effective strategy for the treatment of glioma.

Tetrandrine Exerts a Radiosensitization Effect on Human Glioma through Inhibiting Proliferation by Attenuating ERK Phosphorylation.

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to have a radiosensitization effect on tumors. However, its effects on human glioma and the specific molecular mechanisms of these effects remain unknown. In this study, we demonstrated that Tet has a radiosensitization effect on human glioma cells. It has been hypothesized that Tet has a radiosensitization effect on glioma cells by affecting the glioma cell cycle and DNA repair mechanism and that ERK mediates these activities. Therefore, we conducted detailed analyses of the effects of Tet on the cell cycle by performing flow cytometric analysis and on DNA repair by detecting the expression of phosphorylated H2AX by immunofluorescence. We used western blot analysis to investigate the role of ERK in the effect of Tet on the cell cycle and DNA repair. The results revealed that Tet exerts its radiosensitization effect on glioma cells by inhibiting proliferation and decreasing the expression of phosphorylated ERK and its downstream proteins. In summary, our data indicate that ERK is involved in Tet-induced radiosensitization of glioma cells via inhibition of glioma cell proliferation or of the cell cycle at G0/G1 phase.

[Curcumine inhibits migration and invasion of hepatic stellate cells by reducing MMP-2 expression and activity].

OBJECTIVE: To investigate the molecular mechanism of the inhibitory effect of curcumine on the migration and invasion of hepatic stellate cells (HSC). METHODS: Rat hepatic stellate cells were cultured and activated with ConA. Matrix metalloproteinase-2 (MMP-2) expression and activity was determined by Western blot and gelatin zymography. Migration and invasion of HSC was assessed by wound healing assay and modified Boyden chamber assay. RESULTS: Curcumine reduced the level and activity of MMP-2 expression in activated HSC in a dose-dependent manner. When treated with 25, 50 or 100 micromol/L curcumine, the expression of MMP-2 was reduced by 21.8%+/-5.1%, 65.5%+/-9.2% or 87.9%+/-11.5% (P < 0.05), and the activity of MMP-2 was also significantly reduced by curcumine. Migration and invasion of activated HSC was also inhibited by curcumine in a dose-dependent way. When treated with 25, 50 or 100 micromol/L curcumine, the migration of activated HSC was reduced by 27.5%+/-5.8%, 54.4%+/-7.6% or 67.1%+/-9.3% (P < 0.05), and the invasion of activated HSC was also significantly reduced by curcumine. CONCLUSION: Curcumine inhibits migration and invasion of activated HSC by reducing MMP-2 expression and activity.