RESUMEN
X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1), a XIAP-binding protein, is a tumor suppressor gene. XAF1 was silent or expressed lowly in most human malignant tumors. However, the role of XAF1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we investigated the effect of XAF1 on tumor growth and angiogenesis in hepatocellular cancer cells. Our results showed that XAF1 expression was lower in HCC cell lines SMMC-7721, Hep G2 and BEL-7404 and liver cancer tissues than that in paired non-cancer liver tissues. Adenovirus-mediated XAF1 expression (Ad5/F35-XAF1) significantly inhibited cell proliferation and induced apoptosis in HCC cells in dose- and time- dependent manners. Infection of Ad5/F35-XAF1 induced cleavage of caspase -3, -8, -9 and PARP in HCC cells. Furthermore, Ad5/F35-XAF1 treatment significantly suppressed tumor growth in a xenograft model of liver cancer cells. Western Blot and immunohistochemistry staining showed that Ad5/F35-XAF1 treatment suppressed expression of vascular endothelial growth factor (VEGF), which is associated with tumor angiogenesis, in cancer cells and xenograft tumor tissues. Moreover, Ad5/F35-XAF1 treatment prolonged the survival of tumor-bearing mice. Our results demonstrate that XAF1 inhibits tumor growth by inducing apoptosis and inhibiting tumor angiogenesis. XAF1 may be a promising target for liver cancer treatment.
Asunto(s)
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Péptidos y Proteínas de Señalización Intracelular/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Proteínas de Neoplasias/genética , Proteínas Adaptadoras Transductoras de Señales , Animales , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis , Carcinoma Hepatocelular/irrigación sanguínea , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular/genética , Regulación hacia Abajo , Terapia Genética , Células HEK293 , Humanos , Neoplasias Hepáticas/irrigación sanguínea , Neoplasias Hepáticas/patología , Ratones , Neovascularización Patológica/genética , Neovascularización Patológica/metabolismo , Neovascularización Patológica/terapia , TransfecciónRESUMEN
Colon cancer is one of the most common cancers. Survivin is overexpressed in human colon cancer and correlate with chemoresistance, angiogenesis and poor prognosis. Oxaliplatin, a platinum derivative cancer drug, has been used for treating human colorectal cancers. In the present study, we investigated the effect of the adeno-associated virus (AAV)-mediated survivin mutant Thr34Ala [rAAV-Sur-Mut(T34A)] on colon cancer growth. Infection with rAAV-Sur-Mut(T34A) inhibited cell proliferation, induced apoptosis and mitotic catastrophe, and sensitized colon cancer cells to chemotherapeutic drugs in vitro. Treatment with rAAV-Sur-Mut(T34A) significantly induced apoptosis, reduced angiogenesis and inhibited colon cancer growth in vivo. More importantly, rAAV-Sur-Mut(T34A) treatment strongly enhanced the anti-tumor activity of oxaliplatin and prolonged animal survival. Thus, the use of rAAV-Sur-Mut(T34A) in combination with chemotherapy may be a promising strategy for colon cancer therapy.
Asunto(s)
Neoplasias del Colon/irrigación sanguínea , Neoplasias del Colon/patología , Dependovirus/genética , Proteínas Inhibidoras de la Apoptosis/genética , Mutación/genética , Neovascularización Patológica/prevención & control , Compuestos Organoplatinos/farmacología , Animales , Antineoplásicos/farmacología , Apoptosis , Western Blotting , Proliferación Celular , Neoplasias del Colon/prevención & control , Femenino , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Humanos , Técnicas para Inmunoenzimas , Proteínas Inhibidoras de la Apoptosis/metabolismo , Ratones , Ratones Endogámicos BALB C , Oxaliplatino , ARN Mensajero/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tasa de Supervivencia , Survivin , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Autophagy is designated as type II programmed cell death and may confer a tumor-suppressive function. Our previous studies have shown that XIAP-associated factor 1 (XAF1) induced apoptosis and inhibited tumor growth in gastric cancer cells. In this study, we investigated the effect of XAF1 on the induction of autophagy in gastric cancer cells. We found that adenovirus vector-mediated XAF1 (adeno-XAF1) expression markedly induced autophagy, upregulated the level of Beclin-1 and inhibited phospho-Akt and phospho-p70S6K in gastric cancer cells. The downregulation of Beclin 1 or 3-methyladenine treatment suppressed adeno-XAF1-induced autophagy, but significantly enhanced adeno-XAF1-induced apoptosis. A pan-caspase inhibitor prevented adeno-XAF1-induced apoptosis, but significantly increased adeno-XAF1-induced autophagy. Furthermore, adeno-XAF1 induced autophagy in xenograft tumor and inhibited tumor growth. Our results document that adeno-XAF1 induces autophagy through upregulation of Beclin 1 expression and inhibition of Akt/p70S6K pathway, and reveal a new mechanism of XAF1 tumor suppression.