RESUMEN
ZBP-89 can enhance tumor cells to death stimuli. However, the molecular mechanism leading to the inhibitory effect of ZBP-89 is unknown. In this study, 4 liver cell lines were used to screen for the target of ZBP-89 on cell death pathway. The identified Bak was further analyzed for its role in ZBP-89-mediated apoptosis. The result showed that ZBP-89 significantly and time-dependently induced apoptosis. It significantly upregulated the level of pro-apoptotic Bak. ZBP-89 targeted a region between -457 and -407 of human Bak promoter to stimulate Bak expression based on the findings of Bak promoter luciferase report gene assay and electrophoretic mobility shift assay. ZBP-89-induced Bak increase and ZBP-89-mediated apoptosis were markedly suppressed by Bak siRNA, confirming that Bak was specifically targeted by ZBP-89 to facilitate apoptosis. In conclusion, this study demonstrated that ZBP-89 significantly induced apoptosis of HCC cells via promoting Bak level.
Asunto(s)
Apoptosis , Carcinoma Hepatocelular/patología , Proteínas de Unión al ADN/metabolismo , Neoplasias Hepáticas/patología , Factores de Transcripción/metabolismo , Proteína Destructora del Antagonista Homólogo bcl-2/genética , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Proliferación Celular , Proteínas de Unión al ADN/genética , Ensayo de Cambio de Movilidad Electroforética , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Luciferasas/metabolismo , Regiones Promotoras Genéticas/genética , ARN Interferente Pequeño/genética , Factores de Transcripción/genética , Células Tumorales Cultivadas , Proteína Destructora del Antagonista Homólogo bcl-2/antagonistas & inhibidores , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismoRESUMEN
ZBP-89 inhibits the some tumor cells but its role in HCC is unknown. We investigated effect of ZBP-89 on cell death of 5 HCC cell lines with different status of p53. We found that ZBP-89 significantly induced cell death of all HCC cells particularly those with wild-type p53. The inhibition was well correlated with the induction of caspase-6 activity. The inhibition of caspase-6 abolished the effect of ZBP-89. ZBP-89 reduced the cells in G2-M but increased them in S phase. With the changes in caspase-6 and cell cycle, ZBP-89 greatly enhanced the killing effectiveness of 5-fluorouracil or staurosporine in HCC cells.