RESUMO
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.
Assuntos
Adenovírus Humanos/genética , Proteínas de Ciclo Celular , Ciclo Celular/genética , Proteínas de Ligação a DNA , Vetores Genéticos/genética , Neoplasias Experimentais/terapia , Fatores de Transcrição/genética , Replicação Viral/genética , Proteínas E1A de Adenovirus/genética , Proteínas E1A de Adenovirus/metabolismo , Adenovírus Humanos/patogenicidade , Animais , Antineoplásicos , Replicação do DNA , DNA Viral/genética , Vírus Defeituosos , Fatores de Transcrição E2F , Fibroblastos/fisiologia , Regulação Viral da Expressão Gênica/genética , Humanos , Camundongos , Camundongos Knockout , Neoplasias Experimentais/patologia , Regiões Promotoras Genéticas , Proteína do Retinoblastoma/genética , Proteína do Retinoblastoma/metabolismo , Taxa de Sobrevida , Transplante Heterólogo , Células Tumorais Cultivadas/patologiaRESUMO
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.
Assuntos
Adenoviridae/genética , Neoplasias/virologia , RNA Viral/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Replicação Viral/genética , Adenoviridae/metabolismo , Proteínas E1A de Adenovirus/genética , Proteínas E1A de Adenovirus/metabolismo , Proteínas E1B de Adenovirus/genética , Proteínas E1B de Adenovirus/metabolismo , Adenovírus Humanos/genética , Adenovírus Humanos/metabolismo , Apoptose , Western Blotting , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Caspase 3 , Inibidores de Caspase , Caspases/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21 , Efeito Citopatogênico Viral/genética , DNA Viral/biossíntese , Células Epiteliais/metabolismo , Células Epiteliais/efeitos da radiação , Células Epiteliais/virologia , Expressão Gênica/genética , Células HCT116 , Humanos , Hibridização in Situ Fluorescente , Modelos Biológicos , Mutação , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Reação em Cadeia da Polimerase , Biossíntese de Proteínas/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-mdm2 , Transporte de RNA , Proteína Supressora de Tumor p14ARF/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Ensaio de Placa Viral , Proteínas Virais/metabolismo , Vacinas Virais , Proteína X Associada a bcl-2RESUMO
Recombinant interleukin-2 (rIL-2) is a pleiotropic cytokine that activates select immune effector cell responses associated with antitumor activity, including antibody-dependent cellular cytotoxicity (ADCC). Rituximab is an anti-CD20 monoclonal antibody that activates ADCC in non-Hodgkin lymphoma (NHL). The ability of rIL-2 to augment rituximab-dependent tumor responses was investigated. The efficacy of rIL-2 in combination with rituximab was evaluated in 2 NHL tumor xenograft models: the CD20hi, rituximab-sensitive, low-grade Daudi model and the CD20lo, aggressive, rituximab-resistant Namalwa model. Combination of rIL-2 plus rituximab was synergistic in a rituximab-sensitive Daudi tumor model, as evidenced by significant tumor regressions and increased time to tumor progression, compared with rIL-2 and rituximab single agents. In contrast, rituximab-resistant Namalwa tumors were responsive to single-agent rIL-2 and showed an increased response when combined with rituximab. Using in vitro killing assays, rIL-2 was shown to enhance activity of rituximab by activating ADCC and lymphokine-activated killer activity. Additionally, the activity of rIL-2 plus rituximab F(ab')2 was similar to that of rIL-2 alone, indicating a critical role for immunoglobulin G1 Fc-FcgammaR-effector responses in mediating ADCC. Antiproliferative and apoptotic tumor responses, along with an influx of immune effector cells, were observed by immunohistochemistry. Collectively, the data suggest that rIL-2 mediates potent tumoricidal activity against NHL tumors, in part, through activation and trafficking of monocytes and natural killer cells to tumors. These data support the mechanistic and therapeutic rationale for combination of rIL-2 with rituximab in NHL clinical trials and for single-agent rIL-2 in rituximab-resistant NHL patients.