Vesicular Stomatitis Virus (VSV) G Glycoprotein Can Be Modified to Create a Her2/Neu-Targeted VSV That Eliminates Large Implanted Mammary Tumors.

Viral oncolytic immunotherapy is a nascent field that is developing tools to direct the immune system to find and eliminate cancer cells. Safety is improved by using cancer-targeted viruses that infect or grow poorly on normal cells. The recent discovery of the low-density lipoprotein (LDL) receptor as the major vesicular stomatitis virus (VSV) binding site allowed for the creation of a Her2/neu-targeted replicating recombinant VSV (rrVSV-G) by eliminating the LDL receptor binding site in the VSV-G glycoprotein (gp) and adding a sequence coding for a single chain antibody (SCA) to the Her2/neu receptor. The virus was adapted by serial passage on Her2/neu-expressing cancer cells resulting in a virus that yielded a 15- to 25-fold higher titer following in vitro infection of Her2/neu+-expressing cell lines than that of Her2/neu-negative cells (~1 × 108/mL versus 4 × 106 to 8 × 106/mL). An essential mutation resulting in a higher titer virus was a threonine-to-arginine change that produced an N-glycosylation site in the SCA. Infection of Her2/neu+ subcutaneous tumors yielded >10-fold more virus on days 1 and 2 than Her2/neu- tumors, and virus production continued for 5 days in Her2/neu+ tumors compared with 3 days that of 3 days in Her2/neu- tumors. rrVSV-G cured 70% of large 5-day peritoneal tumors compared with a 10% cure by a previously targeted rrVSV with a modified Sindbis gp. rrVSV-G also cured 33% of very large 7-day tumors. rrVSV-G is a new targeted oncolytic virus that has potent antitumor capabilities and allows for heterologous combination with other targeted oncolytic viruses. IMPORTANCE A new form of vesicular stomatitis virus (VSV) was created that specifically targets and destroys cancer cells that express the Her2/neu receptor. This receptor is commonly found in human breast cancer and is associated with a poor prognosis. In laboratory tests using mouse models, the virus was highly effective at eliminating implanted tumors and creating a strong immune response against cancer. VSV has many advantages as a cancer treatment, including high levels of safety and efficacy and the ability to be combined with other oncolytic viruses to enhance treatment results or to create an effective cancer vaccine. This new virus can also be easily modified to target other cancer cell surface molecules and to add immune-modifying genes. Overall, this new VSV is a promising candidate for further development as an immune-based cancer therapy.

The phosphatase and tensin homolog gene inserted between NP and P gene of recombinant New castle disease virus oncolytic effect test to glioblastoma cell and xenograft mouse model.

BACKGROUND: Glioblastoma is one of the most serious brain cancer. Previous studies have demonstrated that PTEN function disorder affects the causing and exacerbation of glioblastoma. Newcastle disease virus (NDV) has been studied as a cancer virotherapeutics. In this study, PTEN gene was delivered to glioblastoma by recombinant NDV (rNDV) and translated into protein at the cytoplasm of the glioblastoma. METHODS: We did comparison tests PTEN protein expression efficiency and oncolytic effect depend on the PTEN gene insertion site at the between NP and P genes and the between P and M gene. PTEN protein mRNA transcription, translation in glioblastoma cell, and functional PTEN protein effect of the rNDV in vitro and in vivo test performed using western blotting, RT-qPCR, MTT assay, and Glioblastoma xenograft animal model test. RESULTS: The result of this study demonstrates that rNDV-PTEN kills glioblastoma cells and reduces cancer tissue better than rNDV without the PTEN gene. In molecular immunological and cytological assays, PTEN expression level was high at located in the between NP and P gene, and PTEN gene was successfully delivered to the glioblastoma cell using rNDV and PTEN gene translated to functional protein and inhibits hTERT and AKT gene. CONCLUSIONS: PTEN gene enhances the oncolytic effect of the rNDV. And our study demonstrated that NP and P gene site is better than P and M gene site which is commonly and conventionally used. PTEN gene containing rNDV is a good candidate virotherapeutics for glioblastoma.

Persistent Infection of a Canine Histiocytic Sarcoma Cell Line with Attenuated Canine Distemper Virus Expressing Vasostatin or Granulocyte-Macrophage Colony-Stimulating Factor.

Canine histiocytic sarcoma (HS) represents a neoplasia with poor prognosis. Due to the high metastatic rate of HS, there is urgency to improve treatment options and to prevent tumor metastases. Canine distemper virus (CDV) is a single-stranded negative-sense RNA (ssRNA (-)) virus with potentially oncolytic properties. Moreover, vasostatin and granulocyte-macrophage colony-stimulating factor (GM-CSF) are attractive molecules in cancer therapy research because of their anti-angiogenetic properties and potential modulation of the tumor microenvironment. In the present study, an in vitro characterization of two genetically engineered viruses based on the CDV strain Onderstepoort (CDV-Ond), CDV-Ondneon-vasostatin and CDV-Ondneon-GM-CSF was performed. Canine histiocytic sarcoma cells (DH82 cells) were persistently infected with CDV-Ond, CDV-Ondneon, CDV-Ondneon-vasostatin and CDV-Ondneon-GM-CSF and characterized on a molecular and protein level regarding their vasostatin and GM-CSF production. Interestingly, DH82 cells persistently infected with CDV-Ondneon-vasostatin showed a significantly increased number of vasostatin mRNA transcripts. Similarly, DH82 cells persistently infected with CDV-Ondneon-GM-CSF displayed an increased number of GM-CSF mRNA transcripts mirrored on the protein level as confirmed by immunofluorescence and Western blot. In summary, modified CDV-Ond strains expressed GM-CSF and vasostatin, rendering them promising candidates for the improvement of oncolytic virotherapies, which should be further detailed in future in vivo studies.

Constitutive low expression of antiviral effectors sensitizes melanoma cells to a novel oncolytic virus.

STAT1 is a critical effector and a target gene of interferon (IFN) signaling, and thus a central mediator of antiviral responses. As both a mediator and a target of IFN signals, STAT1 expression reports on, and determines IFN activity. Gene expression analyses of melanoma patient samples revealed varied levels of STAT1 expression, which highly correlated with expression of >700 genes. The ability of oncolytic viruses to exploit tumor-induced defects to antiviral responses suggests that oncolytic viruses may efficiently target a subset of melanomas, yet these should be defined. We modeled this scenario with murine B16F10 melanomas, immortalized skin fibroblasts as controls and a novel oncolytic virus, EHDV-TAU. In B16F10 cells, constitutive low expression of STAT1 and its target genes, which included intracellular pattern recognition receptors (PRRs), correlated with their inability to mount IFN-based antiviral responses upon EHDV-TAU challenge, and with potency of EHDV-TAU-induced oncolysis. This underexpression of interferon stimulated genes (ISGs) and PRRs, and the inability of EHDV-TAU to induce their expression, were reversed by epigenetic modifiers, suggesting epigenetic silencing as a basis for their underexpression. Despite their inability to mount IFN/STAT-based responses upon viral infection, EHDV-TAU infected B16F10 cells secreted immune-stimulatory chemokines. Accordingly, in vivo, EHDV-TAU enhanced intratumoral infiltration of cytotoxic T-cells and reduced growth of local and distant tumors. We propose that "STAT1 signatures" should guide melanoma virotherapy treatments, and that oncolytic viruses such as EHDV-TAU have the potential to exploit the cellular context of low-STAT1 tumors.

Polymorphisms in the Most Oncolytic Reovirus Strain Confer Enhanced Cell Attachment, Transcription, and Single-Step Replication Kinetics.

Reovirus serotype 3 Dearing (T3D) replicates preferentially in transformed cells and is in clinical trials as a cancer therapy. Laboratory strains of T3D, however, exhibit differences in plaque size on cancer cells and differences in oncolytic activity in vivo This study aimed to determine why the most oncolytic T3D reovirus lab strain, the Patrick Lee laboratory strain (T3DPL), replicates more efficiently in cancer cells than other commonly used laboratory strains, the Kevin Coombs laboratory strain (T3DKC) and Terence Dermody laboratory (T3DTD) strain. In single-step growth curves, T3DPL titers increased at higher rates and produced ∼9-fold higher burst size. Furthermore, the number of reovirus antigen-positive cells increased more rapidly for T3DPL than for T3DTD In conclusion, the most oncolytic T3DPL possesses replication advantages in a single round of infection. Two specific mechanisms for enhanced infection by T3DPL were identified. First, T3DPL exhibited higher cell attachment, which was attributed to a higher proportion of virus particles with insufficient (≤3) σ1 cell attachment proteins. Second, T3DPL transcribed RNA at rates superior to those of the less oncolytic T3D strains, which is attributed to polymorphisms in M1-encoding µ2 protein, as confirmed in an in vitro transcription assay, and which thus demonstrates that T3DPL has an inherent transcription advantage that is cell type independent. Accordingly, T3DPL established rapid onset of viral RNA and protein synthesis, leading to more rapid kinetics of progeny virus production, larger virus burst size, and higher levels of cell death. Together, these results emphasize the importance of paying close attention to genomic divergence between virus laboratory strains and, mechanistically, reveal the importance of the rapid onset of infection for reovirus oncolysis.IMPORTANCE Reovirus serotype 3 Dearing (T3D) is in clinical trials for cancer therapy. Recently, it was discovered that highly related laboratory strains of T3D exhibit large differences in their abilities to replicate in cancer cells in vitro, which correlates with oncolytic activity in a murine model of melanoma. The current study reveals two mechanisms for the enhanced efficiency of T3DPL in cancer cells. Due to polymorphisms in two viral genes, within the first round of reovirus infection, T3DPL binds to cells more efficiency and more rapidly produces viral RNAs; this increased rate of infection relative to that of the less oncolytic strains gives T3DPL a strong inherent advantage that culminates in higher virus production, more cell death, and higher virus spread.

Mesenchymal to epithelial transition driven by canine distemper virus infection of canine histiocytic sarcoma cells contributes to a reduced cell motility in vitro.

Sarcomas especially of histiocytic origin often possess a poor prognosis and response to conventional therapies. Interestingly, tumours undergoing mesenchymal to epithelial transition (MET) are often associated with a favourable clinical outcome. This process is characterized by an increased expression of epithelial markers leading to a decreased invasion and metastatic rate. Based on the failure of conventional therapies, viral oncolysis might represent a promising alternative with canine distemper virus (CDV) as a possible candidate. This study hypothesizes that a CDV infection of canine histiocytic sarcoma cells (DH82 cells) triggers the MET process leading to a decreased cellular motility. Immunofluorescence and immunoblotting were used to investigate the expression of epithelial and mesenchymal markers followed by scratch assay and an invasion assay as functional confirmation. Furthermore, microarray data were analysed for genes associated with the MET process, invasion and angiogenesis. CDV-infected cells exhibited an increased expression of epithelial markers such as E-cadherin and cytokeratin 8 compared to controls, indicating a MET process. This was accompanied by a reduced cell motility and invasiveness. Summarized, these results suggest that CDV infection of DH82 cells triggers the MET process by an increased expression of epithelial markers resulting in a decreased cell motility in vitro.

Improving antitumor efficacy via combinatorial regimens of oncolytic virotherapy.

As a promising therapeutic strategy, oncolytic virotherapy has shown potent anticancer efficacy in numerous pre-clinical and clinical trials. Oncolytic viruses have the capacity for conditional-replication within carcinoma cells leading to cell death via multiple mechanisms, including direct lysis of neoplasms, induction of immunogenic cell death, and elicitation of innate and adaptive immunity. In addition, these viruses can be engineered to express cytokines or chemokines to alter tumor microenvironments. Combination of oncolytic virotherapy with other antitumor therapeutic modalities, such as chemotherapy and radiation therapy as well as cancer immunotherapy can be used to target a wider range of tumors and promote therapeutic efficacy. In this review, we outline the basic biological characteristics of oncolytic viruses and the underlying mechanisms that support their use as promising antitumor drugs. We also describe the enhanced efficacy attributed to virotherapy combined with other drugs for the treatment of cancer.

Orf virus: A promising new therapeutic agent.

The orf virus (ORFV) is a zoonotic, epitheliotropic, DNA parapoxvirus that infects principally sheep and goats. Exposure of animals to the virus or immunization by an ORFV preparation can accentuate the severity of disease, which has provoked an interest in the underlying cellular, virological, and molecular mechanisms. The identified ORFV virulence genes and the fact that the virus can repeatedly infect a host, owing to its evasive mechanisms, contribute to the development of potent immune modulators in various animal species. ORFV has been developed as a vaccine in veterinary medicine. The unique host immune-evasion ability of ORFV has made it an important candidate for vaccine vectors and biological agents (as an oncolytic virus). Genetic modifications using ORFV to obtain safe and efficient preparations and mechanistic studies are improvements to the currently available methods for disease treatment.

Non-Human Primate-Derived Adenoviruses for Future Use as Oncolytic Agents?

Non-human primate (NHP)-derived adenoviruses have formed a valuable alternative for the use of human adenoviruses in vaccine development and gene therapy strategies by virtue of the low seroprevalence of neutralizing immunity in the human population. The more recent use of several human adenoviruses as oncolytic agents has exhibited excellent safety profiles and firm evidence of clinical efficacy. This proffers the question whether NHP-derived adenoviruses could also be employed for viral oncolysis in human patients. While vaccine vectors are conventionally made as replication-defective vectors, in oncolytic applications replication-competent viruses are used. The data on NHP-derived adenoviral vectors obtained from vaccination studies can only partially support the suitability of NHP-derived adenoviruses for use in oncolytic virus therapy. In addition, the use of NHP-derived adenoviruses in humans might be received warily given the recent zoonotic infections with influenza viruses and coronaviruses. In this review, we discuss the similarities and differences between human- and NHP-derived adenoviruses in view of their use as oncolytic agents. These include their genome organization, receptor use, replication and cell lysis, modulation of the host's immune responses, as well as their pathogenicity in humans. Together, the data should facilitate a rational and data-supported decision on the suitability of NHP-derived adenoviruses for prospective use in oncolytic virus therapy.

[The State of The Jak/Stat Pathway Affects the Sensitivity of TumorCells to Oncolytic Enteroviruses].

A test of the sensitivity of seven colon cancer cell lines to a panel of 12 nonpathogenic human enteroviruses revealed significant differences in the ability of tumor cells to become infected and replicate different viral strains. Among the factors that can affect the sensitivity of cells to viruses are differences in the state of the mechanisms of antiviral protection, associated with a reaction to type I interferons. Using the two colon cancer cell lines CaCo2 and LIM1215 as a model, significant differences were revealed in the ability of cells to defend themselves against virus infection after 16 hours of treatment with 1000 units/mL of interferon-alpha. To study the effect of the state of the interferon response system, represented by the Jak/STAT signaling pathway, on the sensitivity of cells to different strains of enteroviruses, HEK293T cell lines were used. These are capable of supporting replication of each of the tested enteroviruses, as well as maintaining the ability to protect against viral infection after the treatment with interferon. Using the CRISPR/Cas9 system, HEK293T sublines with knockouts of the IFNAR1 and STAT2 genes were obtained. The sensitivity of control and knockout cells to infection with five strains of enteroviruses and the vesicular stomatitis virus was analyzed. It was noted that knockout of the IFNAR1 and STAT2 genes resulted in an increased sensitivity to all tested viruses. In knockout cells, the levels of reproduction of the vaccine derived of poliovirus type 1, Echoviruses 7 and 30, and Coxsackie viruses B5 and A7 were also significantly increased in comparison with the control HEK293T cells. Thus, deficiencies in the Jak/STAT signaling pathway in tumor cells lead to an overall increase in the sensitivity to oncolytic viruses.

Delivery of oncolytic vaccinia virus by matched allogeneic stem cells overcomes critical innate and adaptive immune barriers.

BACKGROUND: Previous studies have identified IFNγ as an important early barrier to oncolytic viruses including vaccinia. The existing innate and adaptive immune barriers restricting oncolytic virotherapy, however, can be overcome using autologous or allogeneic mesenchymal stem cells as carrier cells with unique immunosuppressive properties. METHODS: To test the ability of mesenchymal stem cells to overcome innate and adaptive immune barriers and to successfully deliver oncolytic vaccinia virus to tumor cells, we performed flow cytometry and virus plaque assay analysis of ex vivo co-cultures of stem cells infected with vaccinia virus in the presence of peripheral blood mononuclear cells from healthy donors. Comparative analysis was performed to establish statistically significant correlations and to evaluate the effect of stem cells on the activity of key immune cell populations. RESULTS: Here, we demonstrate that adipose-derived stem cells (ADSCs) have the potential to eradicate resistant tumor cells through a combination of potent virus amplification and sensitization of the tumor cells to virus infection. Moreover, the ADSCs demonstrate ability to function as a virus-amplifying Trojan horse in the presence of both autologous and allogeneic human PBMCs, which can be linked to the intrinsic immunosuppressive properties of stem cells and their unique potential to overcome innate and adaptive immune barriers. The clinical application of ready-to-use ex vivo expanded allogeneic stem cell lines, however, appears significantly restricted by patient-specific allogeneic differences associated with the induction of potent anti-stem cell cytotoxic and IFNγ responses. These allogeneic responses originate from both innate (NK)- and adaptive (T)- immune cells and might compromise therapeutic efficacy through direct elimination of the stem cells or the induction of an anti-viral state, which can block the potential of the Trojan horse to amplify and deliver vaccinia virus to the tumor. CONCLUSIONS: Overall, our findings and data indicate the feasibility to establish simple and informative assays that capture critically important patient-specific differences in the immune responses to the virus and stem cells, which allows for proper patient-stem cell matching and enables the effective use of off-the-shelf allogeneic cell-based delivery platforms, thus providing a more practical and commercially viable alternative to the autologous stem cell approach.

Defects in interferon pathways as potential biomarkers of sensitivity to oncolytic viruses.

Increased sensitivity of cancer cells to viruses is a prerequisite for the success of oncolytic virotherapy. One of the major causes of such a phenotype is the disruption of innate antiviral defenses associated with dysfunction of type 1 interferons (IFNs) that permits unlimited replication of viruses in cancer cells. Defects in IFN pathways help cancer progression by providing additional advantages to tumor cells. However, while these defects promote the survival and accelerated proliferation of malignant cells, they facilitate viral replication and thus enhance the efficiency of viral oncolysis. This review describes a broad spectrum of defects in genes that participate in IFN induction and IFN response pathways. Expression levels and/or functional activities of these genes are frequently low or absent in cancer cells, making them sensitive to virus infection. Therefore, certain specific defects in IFN signaling cascades might serve as potential biomarkers to help in identifying individual cancer patients who are likely to benefit from oncolytic virotherapy.

Adenovirus Lacking E1b Efficiently Induces Cytopathic Effect in HPV-16-Positive Murine Cancer Cells via Virus Replication and Apoptosis.

Conditionally replicative adenoviruses (CRAds) replicate poorly in murine cancer cells; however, E1b-deleted CRAds may replicate effectively in HPV16-E6/E7-positive murine cancer cells (TC-1). The HPV16 E7 open reading frame encodes functions analogous to these deleted adenovirus E1 proteins. In this study, an E1b-deleted CRAd (Adhz60) was evaluated for its ability to replicate and induce oncolysis in TC-1 cells. Adhz60-mediated oncolysis was similar in TC-1 and HeLa cells. Productive viral replication was evident based on expression of E1A and hexon, production of infectious virus progeny, and Adhz60-induced apoptosis. The results suggest that TC-1 murine cancer cells allow Adhz60 replication and oncolysis.

Activation of Nrf2 Signaling Augments Vesicular Stomatitis Virus Oncolysis via Autophagy-Driven Suppression of Antiviral Immunity.

Oncolytic viruses (OVs) offer a promising therapeutic approach to treat multiple types of cancer. In this study, we show that the manipulation of the antioxidant network via transcription factor Nrf2 augments vesicular stomatitis virus Δ51 (VSVΔ51) replication and sensitizes cancer cells to viral oncolysis. Activation of Nrf2 signaling by the antioxidant compound sulforaphane (SFN) leads to enhanced VSVΔ51 spread in OV-resistant cancer cells and improves the therapeutic outcome in different murine syngeneic and xenograft tumor models. Chemoresistant A549 lung cancer cells that display constitutive dominant hyperactivation of Nrf2 signaling are particularly vulnerable to VSVΔ51 oncolysis. Mechanistically, enhanced Nrf2 signaling stimulated viral replication in cancer cells and disrupted the type I IFN response via increased autophagy. This study reveals a previously unappreciated role for Nrf2 in the regulation of autophagy and the innate antiviral response that complements the therapeutic potential of VSV-directed oncolysis against multiple types of OV-resistant or chemoresistant cancer.

Importin-ß and exportin-5 are strong biomarkers of productive reoviral infection of cancer cells.

Acute reoviral infection has been extensively studied given the virus's propensity to target malignant cells and activate caspase-3 mediated apoptosis. Reovirus infection of malignant N1E-115 mouse neuroblastoma cells led to significant increased expression of importin-ß and exportin-5 mRNAs (qRTPCR) and proteins (immunohistochemistry) which was partially blocked by small interfering LNA oligomers directed against the reoviral genome. Co-expression analysis showed that the N1E-115 cells that contained reoviral capsid protein had accumulated importin-ß and exportin-5, as well as activated caspase 3. Reoviral oncolysis using a syngeneic mouse model of multiple myeloma similarly induced a significant increase in importin-ß and exportin-5 proteins that were co-expressed with reoviral capsid protein and caspase-3. Apoptotic proteins (BAD, BIM, PUMA, NOXA, BAK, BAX) were increased with infection and co-localized with reoviral capsid protein. Surprisingly the anti-apoptotic MCL1 and bcl2 were also increased and co-localized with the capsid protein suggesting that it was the balance of pro-apoptotic molecules that correlated with activation of caspase-3. In summary, productive reoviral infection is strongly correlated with elevated importin-ß and exportin-5 levels which may serve as biomarkers of the disease in clinical specimens.

[Oncolytic Paramyxoviruses: Mechanism of Action, Preclinical and Clinical Studies].

Preclinical studies demonstrate that a broad spectrum of human and animal malignant cells can be killed by oncolytic paramyxoviruses, which includes cells of ecto-, endo- and mesodermal origin. In clinical trials, significant reduction or even complete elimination of primary tumors and established metastases has been reported. Different routes of virus administration (intratumoral, intravenous, intradermal, intraperito-neal, or intrapleural) and single- vs. multiple-dose administration schemes have been explored. The reported side effects were grades 1 and 2, with the most common among them being mild fever. There are certain advantages in using paramyxoviruses as oncolytic agents compared to members of other virus families exist. Thanks to cytoplasmic replication, paramyxoviruses do not integrate the host genome or engage in recombination, which makes them safer and more attractive candidates for widely used therapeutic oncolysis than ret-roviruses or some DNA viruses. The list of oncolytic Paramyxoviridae members includes the attenuated measles virus, mumps virus, low pathogenic Newcastle disease, and Sendai viruses. Metastatic cancer cells frequently overexpress certain surface molecules that can serve as receptors for oncolytic paramyxoviruses. This promotes specific viral attachment to these malignant cells. Paramyxoviruses are capable of inducing efficient syncytium-mediated lysis of cancer cells and elicit strong immune stimulation, which dramatically enforces anticancer immune surveillance. In general, preclinical studies and phases I-III of clinical trials yield very encouraging results and warrant continued research of oncolytic paramyxoviruses as a particularly valuable addition to the existing panel of cancer-fighting approaches.

Relationship between Cell Receptors and Tumor Cell Sensitivity to Oncolytic Enteroviruses.

Replicative ability of 5 oncolytic enterovirus strains was evaluated on a panel of 18 human normal and tumor cells. The capacity of each cell line to support replication of enterovirus strains varied. Cell lines weakly replicating one virus could be highly sensitive to another viral strain. Differences in the expression of CXADR cell receptor did not correlate with susceptibility to infection and replication of Coxsackie B virus, but complete inactivation of CXADR gene and poliovirus receptor gene (PVR) led to loss of the sensitivity to Coxsackie B5 and poliovirus, respectively. Detection of additional expression markers will contribute to understanding the causes of different sensitivity of tumor cells to viruses.

Reduced angiogenic gene expression in morbillivirus-triggered oncolysis in a translational model for histiocytic sarcoma.

Histiocytic sarcoma represents a rare malignant tumour with a short survival time, indicating the need of novel treatment strategies including oncolytic virotherapy. The underlying molecular mechanisms of viral oncolysis are largely unknown. As cancer in companion animals shares striking similarities with human counterparts, we chose a permanent canine histiocytic sarcoma cell line (DH82 cells) to identify global transcriptome changes following infection with canine distemper virus (CDV), a paramyxovirus closely related to human measles virus. Microarray analysis identified 3054 differentially expressed probe sets (DEPs), encoding for 892 up- and 869 down-regulated unique canine genes, respectively, in DH82 cells persistently infected with the vaccine strain Onderstepoort of CDV (DH82-Ond-pi), compared to non-infected DH82 cells. Up-regulated genes were predominantly related to immune processes, as demonstrated by functional enrichment analysis. Moreover, there was substantial enrichment of genes characteristic for classically activated M1 and alternatively activated M2 macrophages in DH82-Ond-pi; however, significant polarization into either of both categories was lacking. 'Angiogenesis' was the dominant enriched functional term for the down-regulated genes, highlighting decreased blood vessel generation as a potential mechanism of paramyxovirus-induced oncolysis in DH82 cells. The anti-angiogenic effect of infection was verified by immunohistochemistry, which revealed a lower blood vessel density in an in vivo mouse model, xenotransplanted with DH82-Ond-pi, compared to mice transplanted with non-infected DH82 cells. Reduction in angiogenesis appears to be an important oncolytic mechanism of CDV in DH82 cells, suggesting that similar mechanisms might account for human histiocytic sarcoma and maybe other tumours in conjunction with measles virus.

Recombinant Newcastle disease virus (NDV/Anh-IL-2) expressing human IL-2 as a potential candidate for suppresses growth of hepatoma therapy.

Newcastle disease virus (NDV) have shown oncolytic therapeutic efficacy in preclinical study and are currently approved for clinical trials. NDV Anhinga strain which is a mesogenic strain should be classified as lytic strain and has a therapeutic efficacy in hepatocellular cancer. In this study, we evaluated the capacity of NDV Anhinga strain to elicit immune reaction in vivo and the possibility for using as a vaccine vector for expressing tumor therapeutic factors. Interleukin-2 (IL-2) could boost the immune response against the tumor cells. Therefore, we use NDV Anhinga strain as backbone to construct a recombinant virus (NDV/Anh-IL-2) expressing IL-2. The virus growth curve showed that the production of recombinant NDV/Anh-IL-2 was slightly delayed compared to the wild type. The NDV/Anh-IL-2 strain could express soluble IL-2 and effectively inhibit the growth of hepatocellular carcinoma in vivo. 60 days post-treatment, mice which were completely cured by previous treatment were well protected when rechallenged with the same tumor cell. From the H&E-stained sections, intense infiltration of lymphocyte was observed in the NDV Anhinga strain treated group, especially in NDV/Anh-IL-2 group. The NDV Anhinga strain could not only kill the tumor directly, but could also elicit immune reaction and a potent immunological memory when killing tumor in vivo. In conclusion, the Anhinga strain could be an effective vector for tumor therapy; the recombinant NDV/Anh-IL-2 strain expressing soluble IL-2 is a promising candidate for hepatoma therapy.

Oncolytic Therapy of Solid Tumors by Modified Vesicular Stomatitis Virus.

Vesicular stomatitis virus (VSV) is a promising oncolytic virus for treating solid tumors. We recently engineered a replicating VSV that specifically targets and destroys Her2/neu-expressing cancer cells. This virus was created by eliminating its natural binding site and adding a coding sequence for a single chain antibody to the Her2/neu receptor into its genome. Such an approach can be tailored to target various cellular surface molecules. This mini review will discuss genomic modifications of VSVs and their role in oncolytic therapy and discuss some challenges for moving VSVs to clinical applications.