RESUMEN
We have engineered a human adenovirus, ONYX-411, that selectively replicates in human tumor cells, but not normal cells, depending upon the status of their retinoblastoma tumor suppressor protein (pRB) pathway. Early and late viral gene expression as well as DNA replication were significantly reduced in a functional pRB-pathway-dependent manner, resulting in a restricted replication profile similar to that of nonreplicating adenoviruses in normal cells both in vitro and in vivo. In contrast, the viral life cycle and tumor cell killing activity of ONYX-411 was comparable to that of wild-type adenovirus following infection of human tumor cells in vitro as well as after systemic administration in tumor-bearing animals.
Asunto(s)
Adenovirus Humanos/genética , Proteínas de Ciclo Celular , Ciclo Celular/genética , Proteínas de Unión al ADN , Vectores Genéticos/genética , Neoplasias Experimentales/terapia , Factores de Transcripción/genética , Replicación Viral/genética , Proteínas E1A de Adenovirus/genética , Proteínas E1A de Adenovirus/metabolismo , Adenovirus Humanos/patogenicidad , Animales , Antineoplásicos , Replicación del ADN , ADN Viral/genética , Virus Defectuosos , Factores de Transcripción E2F , Fibroblastos/fisiología , Regulación Viral de la Expresión Génica/genética , Humanos , Ratones , Ratones Noqueados , Neoplasias Experimentales/patología , Regiones Promotoras Genéticas , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismo , Tasa de Supervivencia , Trasplante Heterólogo , Células Tumorales Cultivadas/patologíaRESUMEN
ONYX-015 is an adenovirus that lacks the E1B-55K gene product for p53 degradation. Thus, ONYX-015 was conceived as an oncolytic virus that would selectively replicate in p53-defective tumor cells. Here we show that loss of E1B-55K leads to the induction, but not the activation, of p53 in ONYX-015-infected primary cells. We use a novel adenovirus mutant, ONYX-053, to demonstrate that loss of E1B-55K-mediated late viral RNA export, rather than p53 degradation, restricts ONYX-015 replication in primary cells. In contrast, we show that tumor cells that support ONYX-015 replication provide the RNA export function of E1B-55K. These data reveal that tumor cells have altered mechanisms for RNA export and resolve the controversial role of p53 in governing ONYX-015 oncolytic selectivity.