RESUMEN
OBJECTIVES: We investigated the effects of xeroderma pigmentosum D (XPD) on the growth of hepatoma cells and the expressions of P21, Bax, Bcl-2 and Hepatitis B virus X protein (HBx). In addition, we examined whether XPD affected the aforementioned genes via the P53 pathway. METHODS: Human hepatoma cells (HepG2.2.15) were transfected with XPD expression vector, followed by incubation with Pifithrin-α (P53 inhibitor). By using RT-PCR and Western blotting, the expression levels of XPD, P53, phospho-P53 (ser-15), P21, Bax, Bcl-2 and HBx were detected. The cell cycle and the apoptosis rate were examined with flow cytometry, and the cell viability was detected by MTT. RESULTS: Over-expression of XPD up-regulated the expressions of P53, phospho-P53 (ser-15), P21 and Bax but down-regulated the expressions of Bcl-2 and HBx. XPD inhibited the viability of HepG2.2.15 and exacerbated the apoptosis. However, the inhibition of P53 by Pifithrin-α abolished the above-mentioned effects of XPD. CONCLUSION: XPD could suppress growth of hepatoma cells, up-regulate the expressions of P21 and Bax, and down-regulate the expressions of Bcl-2 and HBx through the P53 pathway. There may be mutual influences among XPD, P53 and HBx that co-regulate hepatocarcinogenesis.
Asunto(s)
Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Transactivadores/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/metabolismo , Proteína de la Xerodermia Pigmentosa del Grupo D/metabolismo , Benzotiazoles/farmacología , Carcinoma Hepatocelular/metabolismo , Proliferación Celular , Supervivencia Celular , Regulación hacia Abajo , Células Hep G2 , Humanos , Neoplasias Hepáticas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2 , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Tolueno/análogos & derivados , Tolueno/farmacología , Transactivadores/metabolismo , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteínas Reguladoras y Accesorias Virales , Proteína de la Xerodermia Pigmentosa del Grupo D/genética , Proteína X Asociada a bcl-2/metabolismoRESUMEN
We investigated the role of XPD in cell apoptosis of hepatoma and its relationship with p53 during the regulation of hepatoma bio-behavior. RT-PCR and Western blot were used to detect the expression levels of XPD, p53, c-myc, and cdk2. The cell apoptosis and cell cycle were analyzed with flow cytometry. Compared with the control cells, XPD-transfected cells displayed a lower viability and higher apoptosis rate. A decreased expression of p53 gene was detected in XPD-transfected cells. In contrast, both c-myc and cdk2 showed increased expressions of mRNAs and proteins in the transfected cells. Our results indicate that XPD may play an important role in cell apoptosis of hepatoma by inducing an over-expression of p53, but suppressing expressions of c-myc and cdk2.