[Influence of elemene on the expression of Bcl-2 family genes in rat C6 glioma cells].

OBJECTIVE: To observe the effects of elemene on the induction of apoptosis in rat C6 glioma cells and its influence on expression of Bcl-2 family genes. METHODS: Rat C6 glioma cells were cultured. Elemene of the concentrations of 0, 20, 40, 60, and 80 microg/ml were added for 12, 24, 36, 48, and 72 hours respectively. RT-PCR was used to detect the mRNA expression of Bcl-2/Bcl-x/1 genes. Western blotting was used to detect the protein expression of Bcl-2/Bcl-x/1 genes. The apoptosis of the cells was examined by flow cytometry. RESULTS: The cell counts of the 20, 40, 60, and 80 microg/ml elemene groups were 536 +/- 9, 375 +/- 10, 246 +/- 9, and 112 +/- 10/visual field respectively, all significantly lower than that of the 0 microg/ml elemene group (all F = 1292.416, P < 0.05) and the apoptotic rates of the 20, 40, 60, and 80 microg/ml elemene groups were (27 +/- 2)%, (29 +/- 4)%, (32 +/- 3)%, and (35 +/- 5)% respectively with an Ap peak. The protein expression of Bcl-2/Bcl-x/l genes was decreased in the elemene groups dose and time-dependently. The expression of Bax protein was decreased in the elemene groups too, however, not dose and time-dependently. CONCLUSION: Apoptosis caused by elemene may be associated with the down-regulation of Bcl-2/Bcl-x/l genes.

Construction, expression and characterization of human interferon alpha2b-(G4S)n-thymosin alpha1 fusion proteins in Pichia pastoris.

AIM: Interferon alpha2b (IFNalpha2b) and thymosin alpha1 (Talpha1) exhibit synergic effects in the treatment of hepatitis B and hepatitis C when used together. For developing a fusion protein drug, fusion proteins of IFNalpha2b and Talpha1 linked by different lengths of (G4S)n (n = 1-3) were constructed and expressed in Pichia pastoris. METHODS: Using PCR and molecular clone techniques, the fusion genes of IFNalpha2b-(G4S)n-Talpha1 (n = 1-3) were constructed and subcloned into the eukaryotic expression vector pPIC9. After transformation of these plasmids into P. pastoris, the expressed fusion proteins IFNalpha2b-(G4S)n-Talpha1 (n = 1-3) were obtained. These proteins were purified through diethylaminoethyl (DEAE) affinity chromatography and Superdex 75 gel filtration and analyzed by SDS-PAGE and Western blot. Antiviral and E-rosette assays were used to investigate the bioactivities of these fusion proteins. RESULTS: DNA sequencing confirmed that the fusion genes of IFNalpha2b-(G4S)n-Talpha1 (n = 1-3) were correctly cloned to the pPIC9 vector. The recombinant IFNalpha2b-(G4S)n-Talpha1 (n = 1-3) fusion proteins expressed in P. pastoris were purified with DEAE and Superdex 75 gel filtration chromatography. The fusion proteins could be observed on sodium dodecylsulfate-polyacrylamide gel electrophoresis with molecular weight (MW) of 23.2, 22.9, and 22.6 ku, respectively, and reacted to the IFNalpha2b monoclonal antibody and Talpha1 polyclonal antibody. The purified fusion proteins exhibit antiviral activity and can enhance the percentage of E-rosette-forming-cell in E-rosette assay. CONCLUSION: The recombinant IFNalpha2b-(G4S)n-Talpha1 (n = 1-3) fusion proteins were successfully expressed in P. pastoris. Purified fusion proteins exhibit both antiviral activity of IFNalpha2b and immunomodulatory activity of Talpha1 in vitro. These results will be the basis for further evaluation of the fusion proteins' function in vivo.