ABSTRACT
The aim of this study was to investigate the effect of Paris saponin I (PS I) on human gastric carcinoma cell growth and apoptosis and to explore the potential mechanisms. The proliferation of SGC7901 cells was monitored by the MTT cell viability assay, while the nuclear morphology of apoptotic cells was assessed by Hoechst 33258 staining. Flow cytometry was performed to analyze the cell cycle progression of propidium iodide (PI)-stained SGC7901 cells and the apoptotic rate of annexin V/PI-stained cells. Western blotting was used to examine the expression of several cell cycle proteins, including cyclin B1 and Cdk1, and the apoptosis-regulated proteins Bcl-2, Bax, cytochrome c, procaspase-9, and procaspase-3. The MTT assay demonstrated that PS I could induce significant dose- and time-dependent inhibition of SGC7901 cell proliferation. Marked morphological changes, including condensation of chromatin, nuclear fragmentation and apoptotic bodies were clearly shown on Hoechst 33258 staining. PSI treatment also resulted in the disruption of the cell cycle at G(2)/M and the induction of apoptosis. Following PSI treatment, the cell cycle-related proteins cyclin B1 and Cdk1 were down-regulated. Expression of the pro-apoptotic protein Bax was increased, while anti-apoptotic protein Bcl-2 decreased. PSI treatment resulted in elevated cytoplasmic cytochrome c and activation of the apoptotic proteases caspase-9 and caspase-3. These data indicate that PS acts as an inhibitor of proli I feration in SGC7901 cells by inducing cell cycle arrest and mitochondria-dependent apoptosis. PSI is a potential therapeutic agent against human gastric carcinoma.
ABSTRACT
OBJECTIVE@#To investigate the effect of high mobility group box-1 protein (HMGB1) on the proliferative activity of human hepatoma cell line HepG2 and its potential regulating mechanism.@*METHODS@#The cultured HepG2 cells were treated with recombinant HMGB1 (0, 10, 50, and 100 ng/mL, respectively) for 24 h. Cell proliferation was observed by MTT analysis. Western blot and reverse transcriptase-polymerase chain reaction were used to detect the expression of proliferating cell nuclear antigen (PCNA) and cyclin D1 protein and mRNA, respectively.@*RESULTS@#Compared with the control group, HMGB1 at 10, 50, and 100 ng/mL obviously increased HepG2 cells proliferation, cyclin D1 and PCNA protein and mRNA expression after the treatment for 24 h, respectively (P<0.05). Anti-HMGB1 significantly inhibited the proliferation and cyclin D1 and PCNA mRNA and protein expression of HMGB1 on HepG2 cells (P<0.05).@*CONCLUSION@#Proliferation of HMGB1 on HepG2 cells may be associated with increasing cyclin D1 and PCNA expression. Anti-HMGB1 may have a therapeutic effect on hepatocellular carcinoma.