RESUMO
The Adenovirus (Ad) dl309 mutant, which lacks several E3 region genes, has been used as the backbone for a number of replication selective cytopathic Ads designed to treat tumours. We report that dl309 has enhanced cytopathogenicity in a range of different cell lines when compared with Ad5. The E3 region modifications found in dl309 contributed to reduced late gene expression in both cocksackie-adenovirus receptor (CAR) positive and negative cells. We show that completion of the dl309 viral lifecycle was less efficient and apoptosis was triggered in the CAR negative K1 thyroid cancer-derived cell line. There was increased E1A expression in dl309-infected K1 cells, compared with Ad5, and significantly, whereas E1A in Ad5-infected cells was distributed both in the nuclear and cytoplasmic compartments, E1A was predominantly nuclear in dl309-infected K1 cells. From these results we conclude that the regions of dl309 that are deleted or otherwise modified can contribute to viral replication and inhibition of apoptosis, possibly indirectly by regulating E1A. These data have implications in the development of dl309-based Ads for the treatment of tumours in vivo.
Assuntos
Adenoviridae/patogenicidade , Proteínas E3 de Adenovirus/deficiência , Apoptose , Terapia Viral Oncolítica , Vírus Oncolíticos/patogenicidade , Neoplasias da Glândula Tireoide/terapia , Replicação Viral , Adenoviridae/fisiologia , Proteínas E1A de Adenovirus/biossíntese , Proteínas E3 de Adenovirus/genética , Linhagem Celular Tumoral , Receptor Constitutivo de Androstano , Regulação Neoplásica da Expressão Gênica , Regulação Viral da Expressão Gênica , Genoma Viral , Interações Hospedeiro-Patógeno , Humanos , Vírus Oncolíticos/fisiologia , Receptores Citoplasmáticos e Nucleares/biossíntese , Neoplasias da Glândula Tireoide/metabolismo , Neoplasias da Glândula Tireoide/virologia , VirulênciaRESUMO
The adenovirus mutant ONYX-015 is in phase III clinical trials as a novel antitumor therapy. Its apparent efficacy is thought to be due to its ability to replicate selectively in tumor cells defective in the signaling pathway for p53. Recent data have shown that p14(ARF), a positive regulator of p53, inhibits ONYX-015 replication in cells with a wild-type p53, a phenotype that characterizes normal cells. We, however, found that ONYX-015 activates p53 in tumor cells and in normal cells and that this can occur without p14(ARF) induction. We also show that ONYX-015 is not attenuated in cells with functional p53, whether or not p14(ARF) is expressed, and that where attenuation does occur, it is cell type specific.