Importance of retinoic acid-inducible gene I and of receptor for type I interferon for cellular resistance to infection by Newcastle disease virus

Molecular Mechanisms of Anti-Neoplastic and Immune Stimulatory Properties of Oncolytic Newcastle Disease Virus

Oncolytic viruses represent interesting anti-cancer agents with high tumor selectivity and immune stimulatory potential. The present review provides an update of the molecular mechanisms of the anti-neoplastic and immune stimulatory properties of the avian paramyxovirus, Newcastle Disease Virus (NDV). The anti-neoplastic activities of NDV include (i) the endocytic targeting of the GTPase Rac1 in Ras-transformed human tumorigenic cells; (ii) the switch from cellular protein to viral protein synthesis and the induction of autophagy mediated by viral nucleoprotein NP; (iii) the virus replication mediated by viral RNA polymerase (large protein (L), associated with phosphoprotein (P)); (iv) the facilitation of NDV spread in tumors via the membrane budding of the virus progeny with the help of matrix protein (M) and fusion protein (F); and (v) the oncolysis via apoptosis, necroptosis, pyroptosis, or ferroptosis associated with immunogenic cell death. A special property of this oncolytic virus consists of its potential for breaking therapy resistance in human cancer cells. Eight examples of this important property are presented and explained. In healthy human cells, NDV infection activates the RIG-MAVs immune signaling pathway and establishes an anti-viral state based on a strong and uninhibited interferon α,ß response. The review also describes the molecular determinants and mechanisms of the NDV-mediated immune stimulatory effects, in which the viral hemagglutinin-neuraminidase (HN) protein plays a prominent role. The six viral proteins provide oncolytic NDV with a special profile in the treatment of cancer.

Thymic transcriptome analysis after Newcastle disease virus inoculation in chickens and the influence of host small RNAs on NDV replication

Newcastle disease (ND), caused by virulent Newcastle disease virus (NDV), is a contagious viral disease affecting various birds and poultry worldwide. In this project, differentially expressed (DE) circRNAs, miRNAs and mRNAs were identified by high-throughput RNA sequencing (RNA-Seq) in chicken thymus at 24, 48, 72 or 96 h post LaSota NDV vaccine injection versus pre-inoculation group. The vital terms or pathways enriched by vaccine-influenced genes were tested through KEGG and GO analysis. DE genes implicated in innate immunity were preliminarily screened out through GO, InnateDB and Reactome Pathway databases. The interaction networks of DE innate immune genes were established by STRING website. Considering the high expression of gga-miR-6631-5p across all the four time points, DE circRNAs or mRNAs with the possibility to bind to gga-miR-6631-5p were screened out. Among DE genes that had the probability to interact with gga-miR-6631-5p, 7 genes were found to be related to innate immunity. Furthermore, gga-miR-6631-5p promoted LaSota NDV replication by targeting insulin induced gene 1 (INSIG1) in DF-1 chicken fibroblast cells. Taken together, our data provided the comprehensive information about molecular responses to NDV LaSota vaccine in Chinese Partridge Shank Chickens and elucidated the vital roles of gga-miR-6631-5p/INSIG1 axis in LaSota NDV replication.

Less Can Be More: The Hormesis Theory of Stress Adaptation in the Global Biosphere and Its Implications

A dose-response relationship to stressors, according to the hormesis theory, is characterized by low-dose stimulation and high-dose inhibition. It is non-linear with a low-dose optimum. Stress responses by cells lead to adapted vitality and fitness. Physical stress can be exerted through heat, radiation, or physical exercise. Chemical stressors include reactive species from oxygen (ROS), nitrogen (RNS), and carbon (RCS), carcinogens, elements, such as lithium (Li) and silicon (Si), and metals, such as silver (Ag), cadmium (Cd), and lead (Pb). Anthropogenic chemicals are agrochemicals (phytotoxins, herbicides), industrial chemicals, and pharmaceuticals. Biochemical stress can be exerted through toxins, medical drugs (e.g., cytostatics, psychopharmaceuticals, non-steroidal inhibitors of inflammation), and through fasting (dietary restriction). Key-lock interactions between enzymes and substrates, antigens and antibodies, antigen-presenting cells, and cognate T cells are the basics of biology, biochemistry, and immunology. Their rules do not obey linear dose-response relationships. The review provides examples of biologic stressors: oncolytic viruses (e.g., immuno-virotherapy of cancer) and hormones (e.g., melatonin, stress hormones). Molecular mechanisms of cellular stress adaptation involve the protein quality control system (PQS) and homeostasis of proteasome, endoplasmic reticulum, and mitochondria. Important components are transcription factors (e.g., Nrf2), micro-RNAs, heat shock proteins, ionic calcium, and enzymes (e.g., glutathion redox enzymes, DNA methyltransferases, and DNA repair enzymes). Cellular growth control, intercellular communication, and resistance to stress from microbial infections involve growth factors, cytokines, chemokines, interferons, and their respective receptors. The effects of hormesis during evolution are multifarious: cell protection and survival, evolutionary flexibility, and epigenetic memory. According to the hormesis theory, this is true for the entire biosphere, e.g., archaia, bacteria, fungi, plants, and the animal kingdoms.

Advances in the Study of Antitumour Immunotherapy for Newcastle Disease Virus

This article reviews the preclinical research, clinical application and development of Newcastle disease virus (NDV) in the field of cancer therapy. Based on the distinctive antitumour properties of NDV and its positive interaction with the patient's immune system, this biologic could be considered a major breakthrough in cancer treatment. On one hand, NDV infection creates an inflammatory environment in the tumour microenvironment, which can directly activate NK cells, monocytes, macrophages and dendritic cells and promote the recruitment of immune cells. On the other hand, NDV can induce the upregulation of immune checkpoint molecules, which may break immune tolerance and immune checkpoint blockade resistance. In fact, clinical data have shown that NDV combined with immune checkpoint blockade can effectively enhance the antitumour response, leading to the regression of local tumours and distant tumours when injected, and this effect is further enhanced by targeted manipulation and modification of the NDV genome. At present, recombinant NDV and recombinant NDV combined with immune checkpoint blockers have entered different stages of clinical trials. Based on these studies, further research on NDV is warranted.

Cancer Vaccines and Oncolytic Viruses Exert Profoundly Lower Side Effects in Cancer Patients than Other Systemic Therapies: A Comparative Analysis

This review compares cytotoxic drugs, targeted therapies, and immunotherapies with regard to mechanisms and side effects. Targeted therapies relate to small molecule inhibitors. Immunotherapies include checkpoint inhibitory antibodies, chimeric antigen receptor (CAR) T-cells, cancer vaccines, and oncolytic viruses. All these therapeutic approaches fight systemic disease, be it micro-metastatic or metastatic. The analysis includes only studies with a proven therapeutic effect. A clear-cut difference is observed with regard to major adverse events (WHO grades 3-4). Such severe side effects are not observed with cancer vaccines/oncolytic viruses while they are seen with all the other systemic therapies. Reasons for this difference are discussed.

New Insights into Mechanisms of Long-term Protective Anti-tumor Immunity Induced by Cancer Vaccines Modified by Virus Infection

The topic is how to achieve long-term protective anti-tumor immunity by anti-cancer vaccination and what are its mechanisms. Cancer vaccines should instruct the immune system regarding relevant cancer targets and contain signals for innate immunity activation. Of central importance is T-cell mediated immunity and thus a detailed understanding of cognate interactions between tumor antigen (TA)-specific T cells and TA-presenting dendritic cells. Microbes and their associated molecular patterns initiate early inflammatory defense reactions that can contribute to the activation of antigen-presenting cells (APCs) and to costimulation of T cells. The concommitant stimulation of naive TA-specific CD4+ and CD8+ T cells with TAs and costimulatory signals occurs in T-APC clusters that generate effectors, such as cytotoxic T lymphocytes and T cell mediated immunological memory. Information about how such memory can be maintained over long times is updated. The role that the bone marrow with its specialized niches plays for the survival of memory T cells is emphasized. Examples are presented that demonstrate long-term protective anti-tumor immunity can be achieved by post-operative vaccination with autologous cancer vaccines that are modified by virus infection.

Genetically Modified Mouse Mesenchymal Stem Cells Expressing Non-Structural Proteins of Hepatitis C Virus Induce Effective Immune Response

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we obtained modified mouse mesenchymal stem cells (mMSCs) simultaneously expressing five nonstructural HCV proteins (NS3-NS5B). The innate immune response to mMSCs was higher than to DNA immunization, with plasmid encoding the same proteins, and to naïve unmodified MSCs. mMSCs triggered strong phagocytic activity, enhanced lymphocyte proliferation, and production of type I and II interferons. The adaptive immune response to mMSCs was also more pronounced than in the case of DNA immunization, as exemplified by a fourfold stronger stimulation of lymphocyte proliferation in response to HCV, a 2.6-fold higher rate of biosynthesis, and a 30-fold higher rate of secretion of IFN-γ, as well as by a 40-fold stronger production of IgG2a antibodies to viral proteins. The immunostimulatory effect of mMSCs was associated with pronounced IL-6 secretion and reduction in the population of myeloid derived suppressor cells (MDSCs). Thus, this is the first example that suggests the feasibility of using mMSCs for the development of an effective anti-HCV vaccine.

Avian Pattern Recognition Receptor Sensing and Signaling

Pattern recognition receptors (PRRs) are a class of immune sensors that play a critical role in detecting and responding to several conserved patterns of microorganisms. As such, they play a major role in the maintenance of immune homeostasis and anti-microbial defense. Fundamental knowledge pertaining to the discovery of PRR functions and their ligands continue to advance the understanding of immune system and disease resistance, which led to the rational design and/or application of various PRR ligands as vaccine adjuvants. In addition, the conserved nature of many PRRs throughout the animal kingdom has enabled the utilization of the comparative genomics approach in PRR identification and the study of evolution, structural features, and functions in many animal species including avian. In the present review, we focused on PRR sensing and signaling functions in the avian species, domestic chicken, mallard, and domestic goose. In addition to summarizing recent advances in the understanding of avian PRR functions, the present review utilized a comparative biology approach to identify additional PRRs, whose functions have been well studied in mammalians but await functional characterization in avian.

Breaking Therapy Resistance: An Update on Oncolytic Newcastle Disease Virus for Improvements of Cancer Therapy

Resistance to therapy is a major obstacle to cancer treatment. It may exist from the beginning, or it may develop during therapy. The review focusses on oncolytic Newcastle disease virus (NDV) as a biological agent with potential to break therapy resistance. This avian virus combines, upon inoculation into non-permissive hosts such as human, 12 described anti-neoplastic effects with 11 described immune stimulatory properties. Fifty years of clinical application of NDV give witness to the high safety profile of this biological agent. In 2015, an important milestone was achieved, namely the successful production of NDV according to Good Manufacturing Practice (GMP). Based on this, IOZK in Cologne, Germany, obtained a GMP certificate for the production of a dendritic cell vaccine loaded with tumor antigens from a lysate of patient-derived tumor cells together with immunological danger signals from NDV for intracutaneous application. This update includes single case reports and retrospective analyses from patients treated at IOZK. The review also presents future perspectives, including the concept of in situ vaccination and the combination of NDV or other oncolytic viruses with checkpoint inhibitors.

Exosomes Carry microRNAs into Neighboring Cells to Promote Diffusive Infection of Newcastle Disease Virus

Newcastle disease virus (NDV), an avian paramyxovirus, was shown to prefer to replicate in tumor cells instead of normal cells; however, this mechanism has not been fully elucidated. Exosomes play a crucial role in intercellular communication due to the bioactive substances they carry. Several studies have shown that exosomes are involved in virus infections. However, the effect that exosomes have on NDV-infected tumor cells is not known. In this study, we focus on the role of exosomes secreted by NDV-infected HeLa cells in promoting NDV replication. Three miRNA candidates (miR-1273f, miR-1184, and miR-198) embraced by exosomes were associated with enhancing NDV-induced cytopathic effects on HeLa cells. Furthermore, luciferase assays, RT-qPCR, and enzyme-linked immunosorbent assay (ELISA) all demonstrated that these miRNAs could suppress interferon (IFN)-β gene expression. Enhanced NDV replication in HeLa cells was identified by Western blot and plaque assays. Based on these results, we speculate that NDV employed exosomes entry into neighboring cells, which carry miRNAs, resulting in inhibition of the IFN pathway and promotion of viral infection. To our knowledge, this is the first report on the involvement of NDV-employed exosomes in tumor cells, and as such, it provides new insights into the development of anti-tumor therapies.

From chemotherapy to biological therapy: A review of novel concepts to reduce the side effects of systemic cancer treatment (Review)

The side effects of systemic chemotherapy used to treat cancer are often severe. For decades, oncologists have focused on treating the tumor, which may result in damage to the tumor-bearing host and its immune system. Recently, much attention has been paid to the immune system of patients and its activation via biological therapies. Biological therapies, including immunotherapy and oncolytic virus (OV) therapy, are often more physiological and well tolerated. The present review elucidated how these therapies work and why these therapies may be better tolerated: i) In contrast to chemotherapy, immunotherapies induce a memory function of the adaptive immunity system; ii) immunotherapies aim to specifically activate the immune system against cancer; side effects are low due to immune tolerance mechanisms, which maintain the integrity of the body in the presence of B and T lymphocytes with their antigen-receptor specificities and; iii) the type I interferon response, which is evoked by OVs, is an ancient innate immune defense system. Biological and physiological therapies, which support the immune system, may therefore benefit cancer treatment. The present review focused on immunotherapy, with the aim of reducing side effects and increasing long-lasting efficacy in cancer therapy.

Regulation of Constitutive Interferon-Stimulated Genes (Isgs) in Tumor Cells Contributes to Enhanced Antitumor Response of Newcastle Disease Virus-Infected Tumor Vaccines

Newcastle disease virus (NDV) is an oncolytic virus. As immunogenicity of tumor cells is enhanced by NDV infection, recombinant NDV-infected tumor vaccines (rNDV-TV) are effective methods for inducing specific immunity. However, several tumor cells resist NDV infection, and tumor specific immunity is not sufficiently induced by rNDV-TV. Therefore, we clarified the factor contributing to the suppression of NDV infection and attempted to improve rNDV-TV. Initially we investigated the correlation between the NDV infection rate and interferon-related gene expression in six murine tumor cell lines. A significant negative correlation was observed between the constitutive gene expression of Interferon-stimulated genes (ISGs) and NDV infectivity. The NDV infection rate was examined in each tumor cell treated with the Janus kinase (JAK) inhibitor ruxolitinib (Rux). Furthermore, we evaluated the Th1 response induction by Rux-treated rNDV-TV (rNDV-TV-Rux). In Rux-treated tumor cells, Oasl2 gene expression was significantly decreased and viral infectivity was increased. In immunized mice, the number of CD8⁺ cells, and those expressing the IFN-γ gene, were significantly increased as compared with Rux-untreated rNDV-TV. The infectivity of the virus was dependent on the degree of ISGs expression in tumor cells. To remedy for this problem, rNDV-TV-Rux was expected to have a Th1 immune response.

Induction of antitumor response to fibrosarcoma by Newcastle disease virus-infected tumor vaccine

Fibrosarcoma is a locally aggressive malignant tumor with a high recurrence rate, so that wide excisional surgery is necessary for treatment. However, it is often difficult to resect with a sufficient margin of excision at the site of tumor infiltration. Recombinant tumor vaccine therapy is a useful method to induce specific immunity. In this study, we have shown its utility as a candidate for therapy by applying a recombinant Newcastle disease virus (rNDV) tumor vaccine (rNDV-TV). Although the therapeutic effect of similar viruses has been examined in several tumors, the vaccination efficacy against fibrosarcoma has not been demonstrated until now. In this study, we showed the induction of an antitumor response by rNDV-TV against murine fibrosarcoma and investigated the role of lymphocytes in tumor elimination. Intraperitoneal inoculation of murine fibrosarcoma (WEHI164) cells showed increased lethality in C.B.17scid/scid (scid) mice within 2 weeks of inoculation. The survival rate increased to 80% when the mice were transfused with CD3⁺ cells from BALB/c mice previously immunized with rNDV-TV. However, all mice died from tumor growth after inoculation with non-immunized CD3⁺ cells. Although the survival rate was around 50% in mice receiving only immunized CD4⁺ and CD8⁺ cells, the survival rate was not decreased in mice receiving CD3⁺CD4^-CD8^- (natural killer T; NKT) cells together with immunized CD4⁺ and CD8⁺ cells. This study showed rNDV-TV induced an antitumor T cell response to WEHI164 cells, and major subsets of cells involved in tumor exclusion were CD4⁺ and CD8⁺ cells, together with NKT cells.

Immunobiology of Newcastle Disease Virus and Its Use for Prophylactic Vaccination in Poultry and as Adjuvant for Therapeutic Vaccination in Cancer Patients

Newcastle disease (ND) is one of the most important diseases of poultry worldwide. In the last decades, molecular research has gained a lot of new information about its causative agent, newcastledisease virus (NDV). In poultry industry, certain strains of NDV have been used for preventive vaccination for more than 60 years. NDV has also been applied to cancer patients with beneficial effects for about 50 years, but this is less well known. The molecular basis for these differential effects of NDV in birds and man have been elucidated in the last decades and are explained in this review. The anti-neoplastic and immune-stimulatory properties in non-permissive hosts such as mouse and man have to do with the strong type I interferon responses induced in these foreign species. Additionally, NDV has the potential to break various types of tumor resistances and also to affect liver fibrosis. A main section is devoted to the benefits of clinical application of NDV and NDV-based vaccines to cancer patients. Reverse genetics technology allowed developing NDV into a vector suitable for gene therapy. Examples will be provided in which genetically engineered NDV is being used successfully as vector against new emerging viruses.

Derivation of chicken induced pluripotent stem cells tolerant to Newcastle disease virus-induced lysis through multiple rounds of infection

Background

Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a devastating disease of poultry and wild birds. ND is prevented by rigorous biocontainment and vaccination. One potential approach to prevent spread of the virus is production of birds that show innate resistance to NDV-caused disease. Induced pluripotent stem cell (iPSC) technology allows adult cells to be reprogrammed into an embryonic stem cell-like state capable of contributing to live offspring and passing on unique traits in a number of species. Recently, iPSC approaches have been successfully applied to avian cells. If chicken induced pluripotent stem cells (ciPSCs) are genetically or epigenetically modified to resist NDV infection, it may be possible to generate ND resistant poultry. There is limited information on the potential of ciPSCs to be infected by NDV, or the capacity of these cells to become resistant to infection. The aim of the present work was to assess the characteristics of the interaction between NDV and ciPSCs, and to develop a selection method that would increase tolerance of these cells to NDV-induced cellular damage.

Results

Results showed that ciPSCs were permissive to infection with NDV, and susceptible to virus-mediated cell death. Since ciPSCs that survived infection demonstrated the ability to recover quickly, we devised a system to select surviving cells through multiple infection rounds with NDV. ciPSCs that sustained 9 consecutive infections had a statistically significant increase in survival (up to 36 times) compared to never-infected ciPSCs upon NDV infection (tolerant cells). Increased survival was not caused by a loss of permissiveness to NDV replication. RNA sequencing followed by enrichment pathway analysis showed that numerous metabolic pathways where differentially regulated between tolerant and never-infected ciPSCs.

Conclusions

Results demonstrate that ciPSCs are permissive to NDV infection and become increasingly tolerant to NDV under selective pressure, indicating that this system could be applied to study mechanisms of cellular tolerance to NDV.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0659-3) contains supplementary material, which is available to authorized users.

Fifty Years of Clinical Application of Newcastle Disease Virus: Time to Celebrate!

This review provides an overview of 50 years of basic and clinical research on an oncolytic avian virus, Newcastle Disease Virus (NDV), which has particular anti-neoplastic and immune stimulatory properties. Of special interest is the fact that this biological agent induces immunogenic cell death and systemic anti-tumor immunity. Furthermore, localized oncolytic virotherapy with NDV was shown to overcome systemic tumor resistance to immune checkpoint blockade immunotherapy. Clinical experience attests to low side effects and a high safety profile. This is due among others to the strong virus-induced type I interferon response. Other viral characteristics are lack of interaction with host cell DNA, lack of genetic recombination and independence of virus replication from cell proliferation. In this millennium, new recombinant strains of viruses are being produced with improved therapeutic properties. Clinical applications include single case observations, case series studies and Phase I to III studies.

Innate sensing of viruses by pattern recognition receptors in birds

Similar to mammals, several viral-sensing pattern recognition receptors (PRR) have been identified in birds including Toll-like receptors (TLR) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLR). Avian TLR are slightly different from their mammalian counterparts, including the pseudogene TLR8, the absence of TLR9, and the presence of TLR1La, TLR1Lb, TLR15, and TLR21. Avian TLR3 and TLR7 are involved in RNA virus recognition, especially highly pathogenic avian influenza virus (HPAIV), while TLR15 and TLR21 are potential sensors that recognize both RNA viruses and bacteria. However, the agonist of TLR15 is still unknown. Interestingly, chickens, unlike ducks, geese and finches, lack RIG-I, however they do express melanoma differentiation-associated gene 5 (MDA5) which functionally compensates for the absence of RIG-I. Duck RIG-I is the cytosolic recognition element for HPAIV recognition, while chicken cells sense HPAIV through MDA5. However, the contributions of MDA5 and RIG-I to IFN-β induction upon HPAIV infection is different, and this may contribute to the chicken’s susceptibility to highly pathogenic influenza. It is noteworthy that the interactions between avian DNA viruses and PRR have not yet been reported. Furthermore, the role for avian Nod-like receptors (NLR) in viral immunity is largely unknown. In this review, recent advances in the field of viral recognition by different types of PRR in birds are summarized. In particular, the tissue and cellular distribution of avian PRR, the recognition and activation of PRR by viruses, and the subsequent expression of innate antiviral genes such as type I IFN and proinflammatory cytokines are discussed.

Oncolytic Newcastle Disease Virus as Cutting Edge between Tumor and Host

Oncolytic viruses (OVs) replicate selectively in tumor cells and exert anti-tumor cytotoxic activity. Among them, Newcastle Disease Virus (NDV), a bird RNA virus of the paramyxovirus family, appears outstanding. Its anti-tumor effect is based on: (i) oncolytic activity and (ii) immunostimulation. Together these activities facilitate the induction of post-oncolytic adaptive immunity. We will present milestones during the last 60 years of clinical evaluation of this virus. Two main strategies of clinical application were followed using the virus (i) as a virotherapeutic agent, which is applied systemically or (ii) as an immunostimulatory agent combined with tumor cells for vaccination of cancer patients. More recently, a third strategy evolved. It combines the strategies (i) and (ii) and includes also dendritic cells (DCs). The first step involves systemic application of NDV to condition the patient. The second step involves intradermal application of a special DC vaccine pulsed with viral oncolysate. This strategy, called NDV/DC, combines anti-cancer activity (oncolytic virotherapy) and immune-stimulatory properties (oncolytic immunotherapy) with the high potential of DCs (DC therapy) to prime naive T cells. The aim of such treatment is to first prepare the cancer-bearing host for immunocompetence and then to instruct the patient's immune system with information about tumor-associated antigens (TAAs) of its own tumor together with danger signals derived from virus infection. This multimodal concept should optimize the generation of strong polyclonal T cell reactivity targeted against the patient's TAAs and lead to the establishment of a long-lasting memory T cell repertoire.

Oncolytic Newcastle disease virus for cancer therapy: old challenges and new directions

Newcastle disease virus (NDV) is an avian paramyxovirus, which has been demonstrated to possess significant oncolytic activity against mammalian cancers. This review summarizes the research leading to the elucidation of the mechanisms of NDV-mediated oncolysis, as well as the development of novel oncolytic agents through the use of genetic engineering. Clinical trials utilizing NDV strains and NDV-based autologous tumor cell vaccines will expand our knowledge of these novel anticancer strategies and will ultimately result in the successful use of the virus in the clinical setting.