【Abstract】Objective To investigate the apoptosis induced by TGF-β1 in human hepatic carcinoma cell lines and its relationship with p53 gene and Smad. Methods Three human hepatic carcinoma cell lines which involving in various status of the p53 gene were used in this study. TGF-β1-induced apoptosis in hepatic carcinoma cell lines was measured by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. To study the mechanism of TGF-β1-induced apoptosis, these cell lines were transfected with a TGF-β1-inducible luciferase reporter plasmid containing Smad 4 binding elements (SBE) and luciferase gene using Lipofectamine 2000, then treated with TGF-β1, relative luciferase activity was assayed. Results Of three cell lines studied with TUNEL assay, TGF-β1 induced apoptosis was observed in HepG2 cells (wild type p53). Huh-7 (mutant p53) and Hep3B (deleted p53) cell lines showed less apoptosis. Luciferase activity assay indicated that the response to TGF-β1 induction in HepG2 cells was increased dramatically but was not significant in Huh-7 and Hep3B cell lines. Conclusion HepG2 cells seem to be highly susceptible to TGF-β1-induced apoptosis compared with Hep3B and Huh7 cell lines. Smad 4 is a central mediator of the TGF-β1 signal transduction pathway.
ObjectiveTo investigate the effects of celastrol on the growth and apoptosis of huamn hepatoma SMMC-7721 cells, and investigate its preliminary action mechansim. MethodsSMMC-7721 cells were cultured in vitro, CCK-8 assay and Annexin V-FITC/PI staining method were conducted to investigate the effects of celastrol on the growth and apoptosis of huamn hepatoma SMMC-7721 cells after the cells were treated with drugs, and then the Caspase-3 activity and NF-κB protein expression were determined by Caspase-3 activity determination kit and Western blot. Huamn hepatoma SMMC-7721 cells transplantation tumor models in nude mice were established and the effect of celastrol on the growth of transplantation tumor were observed. ResultsCelastrol could inhibit the SMMC-7721 cells growth in a dose and time dependent manner. Annexin-V/PI staining showed that SMMC-7721 cells were induced to death with the concentration increasing of celastrol. Caspase-3 activity was measured after treatment with celastrol and the results indicated that the activity of caspase-3 was significantly enhanced. Western blot experiments showed that the expression of NF-κB protein decreased in a time-dependent manner after treatment with celastrol. Celastrol could inhibit SMMC-7721 cells transplantation tumor growth in nude mice. ConclusionsCelastrol could inhibit the proliferation of human hepatoma SMMC-7721 cells and induces apoptosis, and inhibit SMMC-7721 cell transplantation tumor growth in nude mice. Celastrol induce apoptosis of SMMC-7721 cells might through activating Caspase-3 pathway and NF-κB pathway.