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ABSTRACT: Newcastle disease virus (NDV) is an avian paramyxovirus with oncolytic properties which shows promising effects in the treatment of cancer. Anti-cancer effects are due to the virus ability: i) to replicate in and kill tumor cells, leading finally to their selective elimination; and ii) to induce the stimulation of antitumor activities in immune cells. NDV does not harm normal cells and has a high safety profile. In this study, we first report a direct correlation between the degree of cell resistance to NDV infection and the cellular expression of the retinoic acid-inducible gene I (RIG-I) which is a cytosolic viral RNA receptor. RIG-I plays an important role in the recognition of and response to infection by RNA viruses. We also demonstrate that impairment of the interferon (IFN) pathway through deletion of the receptor for type I IFN (IFNR1) in primary macrophages leads to NDV replication. In tumor cells, addition of exogenous IFN-α4 is shown to lead to tumor growth reduction and inhibition of viral replication. Finally, increase of the RIG-I concentration of tumor cells via plasmid transfection is shown to be associated with a stronger resistance to NDV infection. These findings shed new light on the crucial role played by the cytosolic receptor RIG-I and the plasma membrane receptor IFNR1 as key molecules to protect cells against infection by NDV.
International Journal of Oncology 01/2012; 40(1):287-98. · 2.40 Impact Factor
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ABSTRACT: Newcastle disease virus (NDV) is a negative sense RNA paramyxovirus of birds which in human tumor cells, in contrast to human non-tumor cells, has shown replication competence leading to tumor cell death (i.e., tumor selectivity and viral oncolysis). Our study demonstrates that this virus induces high levels of pro-inflammatory cytokines in the bronchial lavage fluid of mice after nasal application and also in vitro in human dendritic cells (DCs). NDV is known as a very efficient inductor of type I interferon (IFN). The presented data show the key role played by the cell surface receptor to type I IFN (IFNAR) but not by the interferon transcription factors IRF-3 and IRF-7 in the induction of the important pro-inflammatory cytokine IL-12 upon transcription of NDV genes in DCs. We show that NDV activates in infected cells the helicase RIG-I. In Tregs, the activation of RIG-I was shown in other studies to inhibit the suppressive function of these cells. We thus conclude that NDV in tumor therapy may help to stimulate T effector cells but also to block Treg cells, thereby alleviating a brake to antitumor activity.
International Journal of Oncology 11/2011; 40(3):840-50. · 2.40 Impact Factor
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ABSTRACT: Newcastle disease virus (NDV) is an interesting agent for activating innate immune activity in macrophages including secretion of TNF-α and IFN-α, upregulation of TRAIL and activation of NF-κB and iNOS. However, the molecular mechanism of such cellular activities remains largely unknown. Tumor selectivity of replication of NDV has been described to be linked to deviations in tumor cells of the type I interferon response. We therefore focused on the interferon response to NDV of macrophages as part of innate anti-viral and anti-tumor activity. In particular, we investigated the functional significance of the interferon regulatory factor genes (IRF)-3 and IRF-7. Deletion of the IRF-3 or IRF-7 gene was found to increase susceptibility of mouse macrophages to virus infection. Surprisingly, NDV replicated better in IRF-3 KO than in IRF-7 KO macrophages. Further analysis showed that IRF-3 KO macrophages have a lower basal and NDV-induced RIG-I expression in comparison to IRF-7 KO macrophages. This might explain why, in IRF-3 KO macrophages, the secretion of type I interferons after NDV infection is delayed, when compared to IRF-7 KO and wild-type macrophages. In addition, IRF-3 KO cells showed reduced NDV-induced levels of IRF-7. This effect could be prevented by priming the cells first by interferon-α. Further results indicated that an early production of type I interferon rather than high maximal levels at later time points are important for resistance to infection by NDV. In conclusion, these results demonstrate an important role of IRF-3 for the innate anti-viral response to NDV of mouse macrophages.
International Journal of Oncology 08/2011; 39(2):493-504. · 2.40 Impact Factor
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ABSTRACT: Newcastle Disease Virus (NDV) is an avian paramyxovirus with anti-neoplastic and immune-stimulatory properties which has raised considerable interest for cancer therapy. To better understand the molecular nature of the tumor selective replication of NDV, we investigated the cellular responses of murine normal and tumor cells after infection by NDV. To this end, we compared the basal expression of different antiviral proteins as well as the expression induced by the addition of NDV to the cells in vitro and in vivo. Primary macrophages were found to be resistant to NDV infection and exhibited a high basal and induced expression of various antiviral genes. In contrast, macrophage-derived RAW tumor cells were highly susceptible to NDV infection and displayed a low expression of several antiviral genes. Macrophage-derived J774 tumor cells were intermediate with regard to NDV replication and antiviral gene expression. The responsiveness to exogenously added IFN-alpha was found highest in normal macrophages, lowest in the RAW cells, and intermediate in the J774 cells. We also analysed dendritic cells as well as additional normal and tumor cell types. A strong inverse correlation was obeserved between the susceptibility to infection and the basal expression of the antiviral genes RIG-I, IRF3, IRF7 and IFN-beta. A strong expression of these genes can explain the resistance of normal cells to NDV infection and a weak antiviral gene expression the broad susceptibility of tumor cells.
International Journal of Oncology 05/2009; 34(4):971-82. · 2.40 Impact Factor
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ABSTRACT: The aim of the study was: i) to specifically target tumor tissue by Newcastle disease virus (NDV) with oncolytic properties, ii) to improve the delivery system for systemic application of NDV via a bispecific adapter protein and iii) to investigate anti-tumor activity and side-effects. We selected two oncolytic virus strains, one native and the other recombinant, which showed multicyclic replication patterns in tumor cells. In order to reduce normal cell binding, they were modified by preincubation with a recombinant bispecific protein which blocks the viral native cell binding site and introduces a new binding site for a tumor-associated target (in this study, the interleukin-2-receptor, IL-2R). After intravenous transfer to mice, uptake of modified NDV in liver, spleen, kidney and lung was greatly reduced in comparison to unmodified NDV as determined by RRT-PCR of viral M gene copies. In IL-2R+ tumor bearing mice, the same assay revealed a high replication efficiency of the modified virus in the tumor tissue. Tumor therapy experiments showed that the side-effects induced by systemic application were greatly reduced by the adapter protein and that the anti-tumor effects were mostly undiminished. The demonstration of significant systemic anti-tumor activity of this viral vector suggests potential for augmentation by inclusion of one or more therapeutic genes.
International Journal of Oncology 01/2007; 29(6):1359-69. · 2.40 Impact Factor
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Holger Wilden
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ABSTRACT: Newcastle Disease Virus (NDV) is an avian Paramyxovirus that preferentially replicates in cancer cells and that has already been used successfully in the treatment of cancer. It has been suggested that defects in the interferon response present in many neoplastic cells make them prone to NDV infection. However, the exact mechanisms that underlie the tumour selective replication of NDV are not known. In this thesis the relation between the NDV susceptibility of cells and the basal and inducible expression of different type I interferon-related proteins was analysed. It was assessed what the differences in the interferon response were between tumour and normal cells and if these differences could explain the tumour selectivity of NDV. It could be shown that tumour cells have defects in the basal and inducible expression of several antiviral, interferon-related genes. These genes include cytosolic viral RNA receptors such as RIG-I, transcription factors such as IRF3 and IRF7, type I interferons and antiviral effector molecules such as PKR. In addition tumour cells displayed defects in the responsiveness to interferon pretreatment with regard to the induction of an antiviral state by the upregulation of antiviral genes. A statistically significant, negative correlation was found between the expression of many of the tested interferon-related genes and the susceptibility to NDV infection. Furthermore the functional significance of some of the genes for the establishment of an antiviral response could be evaluated by the analysis of gene knock out macrophages. These functional analyses revealed the crucial importance of the type I interferon receptor and to a lesser degree also of IRF3/7 for NDV resistance and interferon-related gene expression. Some tumour cells were found to be unusually resistant to NDV infection, which could be connected to an exceptionally strong expression of antiviral genes. All in all the results strongly indicate multiple defects in the interferon response of tumour cells as the cause for the tumour selective replication of NDV. There seems to be a general downregulation of the antiviral gene expression rather than defects in the expression of only a few interferon-related genes. These findings shed new light on the processes that take place in normal and tumour cells after NDV infection. In the future they might be used to improve the efficacy of cancer treatment with NDV by the prediction of the virus susceptibility of a tumour with the help of gene expression analysis before virus treatment. Das Newcastle Disease Virus (NDV) ist ein Vogelvirus das sich bevorzugt in Krebszellen repliziert und das schon erfolgreich in der Behandlung von Krebs angewendet worden ist. Es wird vermutet, dass Defekte in der Interferonantwort viele Krebszellen anfällig für NDV machen. Die genauen Mechanismen, die der tumorselektiven Vermehrung von NDV zugrunde liegen, sind jedoch noch unbekannt. In dieser Arbeit wurde der Zusammenhang zwischen der Anfälligkeit von Zellen für NDV und der basalen und induzierbaren Expression verschiedener Typ I interferonabhängiger Proteine untersucht. Die Unterschiede in der Interferonantwort von normalen und bösartigen Zellen wurden analysiert und es wurde getestet, ob diese Unterschiede die Tumorselektivität von NDV erklären können. Es konnte gezeigt werden, dass Tumorzellen Defekte in der basalen und induzierbaren Expression von einigen antiviralen, interferonabhängigen Genen aufweisen. Zu diesen Genen gehören zytosolische Rezeptoren für virale RNA wie RIG-I, Transkriptionsfaktoren wie IRF3 und IRF7, Typ I Interferone und antivirale Effektormoleküle wie PKR. Darüber hinaus zeigten Tumorzellen Defekte in der Reaktion auf Interferon bezüglich der Induktion eines antiviralen Zustandes durch die Hochregulation antiviraler Gene. Zwischen der Expression vieler der getesteten antiviralen Gene und der Anfälligkeit für NDV wurde eine statistisch signifikante, negative Korrelation beobachtet. Außerdem wurde die funktionelle Bedeutung einiger Gene für die Etablierung einer Interferonantwort mit Hilfe von Knock-out Makrophagen bestimmt. Diese Analyse zeigte die herausragende Bedeutung des Typ I Interferonrezeptors und von IRF3/7 für die Resistenz gegen NDV und für die Expression interferonabhängiger Gene. Einige Tumorzellen waren ungewöhnlich resistent gegen NDV, was mit der hohen Expression von antiviralen Genen erklärt werden konnte. Zusammenfassend deuten die Ergebnisse auf multiple Defekte in der Interferonantwort von Tumorzellen als Ursache für die tumorselektive Vermehrung von NDV hin. Dabei scheint es eher eine generelle Abschwächung der antiviralen Genexpression als Defekte in nur wenigen interferonabhängigen Genen zu geben. Diese Erkenntnisse erhöhen das Verständnis der Prozesse, die in normalen und bösartigen Zellen nach einer NDV-Infektion stattfinden. In der Zukunft könnte dieses Wissen die Krebsbehandlung mit NDV verbessern, indem vor einer Behandlung die Anfälligkeit des Tumors für NDV anhand der Genexpression bestimmt wird.
