Replication efficiency of oncolytic vaccinia virus in cell cultures prognosticates the virulence and antitumor efficacy in mice

Chen, Nanhai G.; Yu, Yong A.; Zhang, Qian; Szalay, Aladar A.

doi:10.1186/1479-5876-9-164

Cited by 25 publications

(23 citation statements)

References 27 publications

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“…As expected, readministration of doxycycline at days 9 and 12 postvirus injection resulted in reinduction of luciferase activity. Moreover, we determined the virus titer at the end of the experiment (13 days postinfection [dpi]) to investigate whether we would be able to detect differences in viral replication, since it has previously been shown that the fewer heterogenous proteins that are expressed, the higher the replication rate is (25). Here, we could not see significant differences between the different virus strains, and the amounts of virus seen with the different groups were similar (Fig.…”

Section: Resultsmentioning

confidence: 70%

Inducible Gene Expression in Tumors Colonized by Modified Oncolytic Vaccinia Virus Strains

Stritzker

Huppertz

Zhang

et al. 2014

J Virol

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Exogenous gene induction of therapeutic, diagnostic, and safety mechanisms could be a considerable improvement in oncolytic virotherapy. Here, we introduced a doxycycline-inducible promoter system (comprised of a tetracycline repressor, several promoter constructs, and a tet operator sequence) into oncolytic recombinant vaccinia viruses (rVACV), which were further characterized in detail. Experiments in cell cultures as well as in tumor-bearing mice were analyzed to determine the role of the inducible-system components. To accomplish this, we took advantage of the optical reporter construct, which resulted in the production of click-beetle luciferase as well as a red fluorescent protein. The results indicated that each of the system components could be used to optimize the induction rates and had an influence on the background expression levels. Depending on the given gene to be induced in rVACV-colonized tumors of patients, we discuss the doxycycline-inducible promoter system adjustment and further optimization. IMPORTANCEOncolytic virotherapy of cancer can greatly benefit from the expression of heterologous genes. It is reasonable that some of those heterologous gene products could have detrimental effects either on the cancer patient or on the oncolytic virus itself if they are expressed at the wrong time or if the expression levels are too high. Therefore, exogenous control of gene expression levels by administration of a nontoxic inducer will have positive effects on the safety as well as the therapeutic outcome of oncolytic virotherapy. In addition, it paves the way for the introduction of new therapeutic genes into the genome of oncolytic viruses that could not have been tested otherwise. Cancer remains one of the major health problems worldwide, and novel therapies are direly needed. Over the past decade, therapies which take advantage of tumor-colonizing microorganisms have gained more and more attention and become a significant field of research followed by ongoing clinical trials. Tumorcolonizing microorganisms include pathogenic, nonpathogenic, and even probiotic bacteria, as well as different virus strains. All of those microorganisms have in common the fact that they colonize and replicate in solid tumors and metastases to a much higher extent than in healthy tissues, resulting in tumor-to-organ ratios that by far exceed any other targeted therapies that are based on small molecules and therapeutic antibodies. This phenomenon of tumor-specific enrichment and amplification is either a consequence of rational genetic engineering or based on natural traits of those microorganisms or both. Whatever the basis for the tumorspecific replication is, tumor-colonizing microorganisms are now being used to (over)express heterologous therapeutic proteins within tumor tissues, thereby enhancing the therapeutic efficacy.Some of those therapeutic proteins can be toxic to the patient or even to the microorganism that produces the protein. Therefore, it would be beneficial to exogenously regulate their gene ...

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Section: Resultsmentioning

confidence: 70%

Inducible Gene Expression in Tumors Colonized by Modified Oncolytic Vaccinia Virus Strains

Stritzker

Huppertz

Zhang

et al. 2014

J Virol

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“…Worschech et al demonstrated several pathways also common in our study including interferon, IL-6, JAK/STAT, PTEN, and ERK/MAPK signaling. 25 Only purine metabolism was a common pathway with Reinboth et al 's study. 26 Like Worschech et al, most of our postinfection cellular gene changes reflected a downregulation and shut down of cellular metabolism.…”

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confidence: 83%

“…26 Like Worschech et al, most of our postinfection cellular gene changes reflected a downregulation and shut down of cellular metabolism. 25 It is difficult to directly compare changes in gene expression due to RNA isolation from tissue rather than cells, adding the variable of the host immune response and gene expression changes which cannot be assessed in cell culture.…”

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confidence: 99%

Molecular network, pathway and functional analysis of time-dependent gene changes associated with pancreatic cancer susceptibility to oncolytic vaccinia virotherapy

Haddad¹,

Socci²,

Chen³

et al. 2011

Journal of the American College of Surgeons

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BACKGROUNDOncolytic viral therapies have shown such success in preclinical trials as a novel cancer treatment modality that several phase 1 and 2 trials are already underway. 1 We have previously reported on the construction and generation of a novel attenuated replication-competent vaccinia virus (VACV), GLV-1h153, a derivative of parental virus GLV-1h68 engineered to carry the human sodium iodide symporter (hNIS) for the imaging of viral replication within tumors via enhanced uptake of several radionuclide probes. 2The noninvasive tracking of virus delivery may enable clinicians to correlate efficacy and therapy, monitor potential viral toxicity, and possibly provide a more sensitive and specific diagnostic technique to detect tumor origin and, more importantly, presence of metastases.3,4 GLV-1h153 facilitated enhanced dose-dependent radiouptake in cell culture and effective replication and killing of pancreatic cancer cells both in cell culture and in animal models. Furthermore, Received 27 December 2015; accepted 2 February 2016 Background: Pancreatic cancer is a fatal disease associated with resistance to conventional therapies. This study aimed to determine changes in gene expression patterns associated with infection and susceptibility of pancreatic cancer cells to an oncolyticvaccinia virus, GLV-1h153, carrying the human sodium iodide symporter for deep tissue imaging of virotherapy.Methods: Replication and susceptibility of pancreatic adenocarcinoma PANC-1 cells to GLV-1h153 was confirmed with replication and cytotoxicity assays. PANC-1 cells were then infected with GLV-1h153 and near-synchronous infection confirmed via flow cytometry of viral-induced green fluorescent protein (GFP) expression. Six and 24 hours after infection, three samples of each time point were harvested, and gene expression patterns assessed using HG-U133A cDNA microarray chips as compared to uninfected control. Differentially expressed genes were identified using Bioconductor LIMMA statistical analysis package. A fold change of 2.0 or above was used as a cutoff, with a P value of 0.01. The gene list was then analyzed using Ingenuity Pathways Analysis software.Results: Differential gene analysis revealed a total of 12,412 up-and 11,065 downregulated genes at 6 and 24 hours postinfection with GLV-1h153 as compared to control. At 6 hours postinfection. A total of 139 genes were either up or downregulated >twofold (false discovery rate < 0.05), of which 124 were mapped by Ingenuity Pathway Analysis (IPA). By 24 hours postinfection, a total of 5,698 genes were identified and 5,563 mapped by IPA. Microarray revealed gene expression changes, with gene networks demonstrating downregulation of processes such as cell death, cell cycle, and DNA repair, and upregulation of infection mechanisms (P < 0.01). Six hours after infection, gene changes involved pathways such as HMGB-1, interleukin (IL)-2, IL-6, IL-8, janus kinase/signal tranducer and activator of transcription (JAK/STAT), interferon, and ERK 5 signaling (P < 0.01). By 24 hours, pr...

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“…In addition, it was found recently that removal of each of the expression cassettes from GLV-1h68 resulted in enhanced virus replication and virulence in mice. The increase in virus replication efficiency was proportionate to the strength of removed VACV promoters linked to foreign genes (Chen et al, 2011).…”

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confidence: 99%

“…Three isolates that showed natural attenuations due to point mutations and deletions were picked for further analysis, namely LIVP 1.1.1, LIVP 5.1.1, and LIVP 6.1.1. The generation of the recombinant VACV strains GLV-1h70, GLV-1h71, GLV-1h72, GLV-1h73, and GLV-1h74 was described previously (Chen et al, 2011).…”

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Correlates Between Host and Viral Transcriptional Program Associated with Different Oncolytic Vaccinia Virus Isolates

Reinboth

Ascierto

Chen

et al. 2012

Human Gene Therapy Methods

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Vaccinia virus (VACV) has emerged as an attractive tool in oncolytic virotherapy. VACV replication efficiency plays a crucial role in the therapeutic outcome. However, little is known about the influence of host factors on viral replication efficiency and permissiveness of a host cell line to infection and oncolysis. In this study, replication of the attenuated VACV GLV-1h68 strain and three wild-type VACV isolates was determined in two autologous human melanoma cell lines (888-MEL and 1936-MEL). Host gene expression and viral gene expression in infected cells were evaluated via respective expression array platforms.Microarray analyses followed by sequential statistical approaches characterized human genes that change specifically due to virus infection. Viral gene transcription correlated with viral replication in a time-dependent manner. A set of human genes revealed strong correlations with the respective viral gene expression. Finally we identified a set of human genes with possible predictive value for viral replication in an independent dataset.The results demonstrate a probable correlation between viral replication, early gene expression, and the respective host response, and thus a possible involvement of human host factors in viral early replication. The characterization of human target genes that influence viral replication could help answer the question of host cell permissiveness to oncolytic virotherapy and provide important information for the development of novel recombinant vaccinia viruses with improved features to enhance replication rate and hence trigger therapeutic outcome.

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Replication efficiency of oncolytic vaccinia virus in cell cultures prognosticates the virulence and antitumor efficacy in mice

Cited by 25 publications

References 27 publications

Inducible Gene Expression in Tumors Colonized by Modified Oncolytic Vaccinia Virus Strains

Inducible Gene Expression in Tumors Colonized by Modified Oncolytic Vaccinia Virus Strains

Molecular network, pathway and functional analysis of time-dependent gene changes associated with pancreatic cancer susceptibility to oncolytic vaccinia virotherapy

Correlates Between Host and Viral Transcriptional Program Associated with Different Oncolytic Vaccinia Virus Isolates

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