Abortive Adenovirus Infection and Host Range Determinants

Lucher, Lynne A.

doi:10.1007/978-3-642-79496-4_8

Cited by 17 publications

(16 citation statements)

References 137 publications

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“…Murine and simian cells allow viral replication, but a late block prevents viral progeny production (27). With regards to direct evaluation of liver toxicity, before 1976, only small numbers of human primary hepatocytes could be cultured (28).…”

Section: Discussionmentioning

confidence: 99%

A Novel Ex vivo Model System for Evaluation of Conditionally Replicative Adenoviruses Therapeutic Efficacy and Toxicity

Kirby

Rivera

Rein

et al. 2004

Clinical Cancer Research

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Purpose: Current animal tumor models are inadequate for the evaluation of toxicity and efficacy of conditionally replicative adenoviruses. A novel model system is needed that will provide insight into the anticipated therapeutic index of conditionally replicative adenoviruses preclinically. We endeavored to show a novel model system, which involves ex vivo evaluation of conditionally replicative adenovirus toxicity and therapeutic efficacy in thin, precision-cut slices of human primary tumor and liver.Experimental Design: The Krumdieck thin-slice tissue culture system was used to obtain and culture slices of tumor xenografts of ovarian cancer cell lines, human primary ovarian tumors, and human liver. We determined the viability of slices in culture over a period of 36 to 48 hours by ([3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxphenyl-2-(4-sulfophenyl)-2H-tetrazolium, inner salt)]) (MTS) assay. In vitro Hey cells, slices of Hey xenografts, and human ovarian tumor or human liver slices were infected with 500vp/cell of either replication competent wild-type adenovirus (Ad5/3wt), conditionally replicative adenovirus (Ad5/3cox-2), or the replication deficient adenovirus (Ad5/3luc1). At 12-, 24-, and 36-hour intervals, the replication of adenoviruses in these slices was determined by quantitative reverse transcription-PCR of adenoviral E4 copy number.Results: Primary tumor slices were able to maintain viability for up to 48 hours after infection with nonreplicative virus (Ad5luc1). Infection of Hey xenografts with Ad5/ 3cox-2 showed replication consistent with that seen in Hey cells infected in an in vitro setting. Primary tumor slices showed replication of both Ad5/3wt and Ad5/3cox over a 36-hour time period. Human liver slices showed replication of Ad5/3wt but a relative reduction in replication of Ad5/ 3cox-2 indicative of conditional replication "liver off" phenotype, thus predicting lower toxicity. Conclusions:The thin-slice model system represents a stringent method of ex vivo evaluation of novel replicative adenoviral vectors and allows assessment of human liver replication relative to human tumor replication. This is the first study to incorporate this system for evaluation of therapeutic efficacy and replicative specificity of conditionally replicative adenoviruses. Also, the study is the first to provide a valid means for preclinical assay of potential conditionally replicative adenovirus-based hepatotoxicities, thus providing a powerful tool to determine therapeutic index for clinical translation of conditionally replicative adenoviruses.

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Section: Discussionmentioning

confidence: 99%

A Novel Ex vivo Model System for Evaluation of Conditionally Replicative Adenoviruses Therapeutic Efficacy and Toxicity

Kirby

Rivera

Rein

et al. 2004

Clinical Cancer Research

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“…Diminished expression of E2 genes was suggested as a major cause of the early block in Ad12 replication in hamster cells, although reports about the levels of single E2 gene products are contradictory (21,36). Reduced amounts of E1 mRNAs were also reported for abortive Ad12 infection (35). In addition to the expression of certain viral genes, the availability of cellular factors might be crucial for viral DNA replication.…”

Section: Discussionmentioning

confidence: 99%

Biology of Ovine Adenovirus Infection of Nonpermissive Cells

Kümin¹,

Hofmann²,

Rudolph

et al. 2002

J Virol

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Nonhuman adenoviruses, including those of the genus Atadenovirus, have the potential to serve as vectors for vaccine and gene therapy applications in humans, since they are resistant to preexisting immunity induced by human adenoviruses in the majority of the population. In this study, we elucidate the outcome of infection by ovine adenovirus type 7 isolate 287 (OAdV) of several nonovine cell types. We show here that OAdV infects a wide range of nonovine cells but is unable to complete its replication cycle in any of them. In nonovine, nonfibroblast cells, viral replication is blocked at an early stage before the onset of, or early in, DNA replication. Some fibroblasts, on the other hand, allow viral DNA replication but block virus production at a later stage during or after the translation of late viral proteins. Late viral proteins are expressed in cells where viral DNA replication takes place, albeit at a reduced level. Significantly, late proteins are not properly processed, and their cellular distribution differs from that observed in infected ovine cells. Thus, our results clearly show that OAdV infection of all nonovine cells tested is abortive even if significant viral DNA replication occurs. These findings have significant positive implications with respect to the safety of the vector system and its future use in humans.Human adenoviruses have been widely studied over the last 4 decades, and the processes involved in infection and replication have been largely characterized. Abortive infection by human adenoviruses has been investigated in human and several nonhuman cell culture systems (reviewed in reference 35). These studies have provided a better understanding of the molecular biology of human adenoviruses and of events such as the integration of foreign DNA into mammalian genomes and the initiation of malignant transformation by DNA tumor viruses. However, the biology of human adenovirus infection in heterologous cells differs widely for various genotypes, even in the same cell line. For example, baby hamster kidney cells (BHK-21) are semipermissive for adenovirus type 2 (Ad2) and Ad5 replication but block infection with Ad3 and Ad12 at an early step of the viral life cycle (13). The early block in Ad12 replication can be abrogated by constitutive expression of E1 genes from Ad2, -

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“…We then determined if Ad5 could express viral late genes in the context of canine target cell infection. In this regard, crossspecies abortive infection frequently demonstrates only early adenoviral gene expression with an early-to-late transition block (8,14,17,19,25,27,30). Thus, demonstration of late gene expression would suggest viral genome replication and successful early-to-late transition of the viral life cycle.…”

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confidence: 99%

Productive Replication of Human Adenovirus Type 5 in Canine Cells

Ternovoi

Белоусова

et al. 2005

J Virol

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Development of immunocompetent patient-like models that allow direct analysis of human adenovirus-based conditionally replicative adenoviruses (CRAds) would be beneficial for the advancement of these oncolytic agents. To this end, we explored the possibility of cross-species replication of human adenovirus type 5 (Ad5) in canine cells. With a panel of canine tumor cell lines of both epithelial and mesenchymal derivations, we demonstrate that human Ad5 can productively infect canine cells. Since the biological behavior and clinical presentation of certain dog tumors closely resemble those of their human counterparts, our results raise the possibility of exploiting canine models for preclinical analysis of candidate CRAd agents designed for human virotherapy.Conditionally replicative adenovirus (CRAd) agents represent a promising new therapeutic approach for cancer. This strategy is based on the application of an adenovirus engineered to selectively replicate in tumor targets (1, 3). This tumor-selective replication forms the functional basis of the antineoplastic effect achieved by direct target cell killing in a process termed oncolysis (1, 16). The exceptional promise of these agents has predicated their rapid transition to human phase I clinical trials whereby the overall safety of this approach has been validated (15,22,28). Nonetheless, the very limited indications of efficacy to this point have established the requirement for further design advances to enhance CRAd antitumor potency (11,15,20,23).Critical to the derivation of advanced-generation CRAds is the development of model systems capable of delineating key therapeutic indices. For CRAds, the fact that human adenoviruses can accomplish only abortive replication in murine targets (7-9, 17) has restricted the preclinical toxicity information that may be derived from SCID-xenograft model systems typically used for efficacy analysis. Further, these immunologically incompetent models cannot provide useful information with respect to CRAd immunobiology and vector-host interactions. On this basis, it is clear that there exists a field-wide need for immunocompetent syngeneic models for full analysis of candidate CRAd agents. Several recent reports have described model systems to achieve these goals. Hemminki et al. have exploited the availability of human-like canine models of cancer (31) for the evaluation of CRAd agents derived from canine adenoviruses (12,15,31). This approach potentially allows the study of vector-host interactions in an immunocompetent host in the context of a patient-like cancer model. CRAd constructs based on canine adenoviruses, however, may embody substantial biological differences from human adenovirus-based CRAds. Alternatively, an approach has been proposed whereby adapted murine cells permissive for limited human adenovirus replication are transplanted into an immunocompetent mouse host (10,29). Whereas this approach may allow direct analysis of human adenovirus-based CRAds in a murine system, this transplant model does not repre...

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Abortive Adenovirus Infection and Host Range Determinants

Cited by 17 publications

References 137 publications

A Novel Ex vivo Model System for Evaluation of Conditionally Replicative Adenoviruses Therapeutic Efficacy and Toxicity

A Novel Ex vivo Model System for Evaluation of Conditionally Replicative Adenoviruses Therapeutic Efficacy and Toxicity

Biology of Ovine Adenovirus Infection of Nonpermissive Cells

Productive Replication of Human Adenovirus Type 5 in Canine Cells

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