Newcastle disease virus exerts oncolysis by both intrinsic and extrinsic caspase-dependent pathways of cell death

The Application of Newcastle Disease Virus (NDV): Vaccine Vectors and Tumor Therapy

Newcastle disease virus (NDV) is an avian pathogen with an unsegmented negative-strand RNA genome that belongs to the Paramyxoviridae family. While primarily pathogenic in birds, NDV presents no threat to human health, rendering it a safe candidate for various biomedical applications. Extensive research has highlighted the potential of NDV as a vector for vaccine development and gene therapy, owing to its transcriptional modularity, low recombination rate, and lack of a DNA phase during replication. Furthermore, NDV exhibits oncolytic capabilities, efficiently eliciting antitumor immune responses, thereby positioning it as a promising therapeutic agent for cancer treatment. This article comprehensively reviews the biological characteristics of NDV, elucidates the molecular mechanisms underlying its oncolytic properties, and discusses its applications in the fields of vaccine vector development and tumor therapy.

Molecular Circuits of Immune Sensing and Response to Oncolytic Virotherapy

Oncolytic virotherapy is a promising immunotherapy approach for cancer treatment that utilizes viruses to preferentially infect and eliminate cancer cells while stimulating the immune response. In this review, we synthesize the current literature on the molecular circuits of immune sensing and response to oncolytic virotherapy, focusing on viral DNA or RNA sensing by infected cells, cytokine and danger-associated-signal sensing by neighboring cells, and the subsequent downstream activation of immune pathways. These sequential sense-and-response mechanisms involve the triggering of molecular sensors by viruses or infected cells to activate transcription factors and related genes for a breadth of immune responses. We describe how the molecular signals induced in the tumor upon virotherapy can trigger diverse immune signaling pathways, activating both antigen-presenting-cell-based innate and T cell-based adaptive immune responses. Insights into these complex mechanisms provide valuable knowledge for enhancing oncolytic virotherapy strategies.

Synergistic effects of Bacillus coagulans and Newcastle disease virus on human colorectal adenocarcinoma cell proliferation

Background and Objectives

Colorectal cancer (CRC) is a common type of cancer that has a high death rate and is becoming more common in developed countries. Currently, there are several treatment options available for CRC patients, and clinical trials are being conducted to improve conventional therapies. This study investigates the combined impact of Bacillus coagulans (B.C) and Newcastle disease virus (NDV) on the growth of human colorectal adenocarcinoma cells (HT29 cell line).

Materials and Methods

The HT29 cell line was cultured under controlled laboratory conditions. They were treated with Fluorouracil (5-FU), NDV, and B.C., after which various assessments were conducted to determine the effects of these treatments. These assessments included MTT assay for cytotoxicity, evaluation of cell viability, and measurement of caspase 8 and 9 activity levels. The significance of the data was determined at a threshold of P<0.05 following analysis.

Results

The usage of NDV and B.C significantly increased cell death and reduced cell growth in the HT29 cell line, when compared to the control group. Moreover, the combined application of NDV and B.C along with 5-FU exhibited a synergistic effect in decreasing the proliferation of HT29 cells. Additionally, the results indicated that intrinsic apoptosis pathway was activated by B.C and NDV.

Conclusion

It appears that utilizing oncolytic viruses (OV) and bacteria in conjunction with chemotherapy drugs could potentially aid in reducing the growth of colorectal cancer cells. However, further research is necessary, including animal studies, to confirm the efficacy of this treatment method.

Recombinant Newcastle disease viruses expressing immunological checkpoint inhibitors induce a pro-inflammatory state and enhance tumor-specific immune responses in two murine models of cancer

Introduction

Tumor microenvironments are immunosuppressive due to progressive accumulation of mutations in cancer cells that can drive expression of a range of inhibitory ligands and cytokines, and recruitment of immunomodulatory cells, including myeloid-derived suppressor cells (MDSC), tumor-associated macrophages, and regulatory T cells (Tregs).

Methods

To reverse this immunosuppression, we engineered mesogenic Newcastle disease virus (NDV) to express immunological checkpoint inhibitors anti-cytotoxic T lymphocyte antigen-4 and soluble programmed death protein-1.

Results

Intratumoral administration of recombinant NDV (rNDV) to mice bearing intradermal B16-F10 melanomas or subcutaneous CT26LacZ colon carcinomas led to significant changes in the tumor-infiltrating lymphocyte profiles. Vectorizing immunological checkpoint inhibitors in NDV increased activation of intratumoral natural killer cells and cytotoxic T cells and decreased Tregs and MDSCs, suggesting induction of a pro-inflammatory state with greater infiltration of activated CD8+ T cells. These notable changes translated to higher ratios of activated effector/suppressor tumor-infiltrating lymphocytes in both cancer models, which is a promising prognostic marker. Whereas all rNDV-treated groups showed evidence of tumor regression and increased survival in the CT26LacZ and B16-F10, only treatment with NDV expressing immunological checkpoint blockades led to complete responses compared to tumors treated with NDV only.

Discussion

These data demonstrated that NDV expressing immunological checkpoint inhibitors could reverse the immunosuppressive state of tumor microenvironments and enhance tumor-specific T cell responses.

Oncolytic Virotherapy: A New Paradigm in Cancer Immunotherapy

Oncolytic viruses (OVs) are emerging as potential treatment options for cancer. Natural and genetically engineered viruses exhibit various antitumor mechanisms. OVs act by direct cytolysis, the potentiation of the immune system through antigen release, and the activation of inflammatory responses or indirectly by interference with different types of elements in the tumor microenvironment, modification of energy metabolism in tumor cells, and antiangiogenic action. The action of OVs is pleiotropic, and they show varied interactions with the host and tumor cells. An important impediment in oncolytic virotherapy is the journey of the virus into the tumor cells and the possibility of its binding to different biological and nonbiological vectors. OVs have been demonstrated to eliminate cancer cells that are resistant to standard treatments in many clinical trials for various cancers (melanoma, lung, and hepatic); however, there are several elements of resistance to the action of viruses per se. Therefore, it is necessary to evaluate the combination of OVs with other standard treatment modalities, such as chemotherapy, immunotherapy, targeted therapies, and cellular therapies, to increase the response rate. This review provides a comprehensive update on OVs, their use in oncolytic virotherapy, and the future prospects of this therapy alongside the standard therapies currently used in cancer treatment.

Reverse Genetics Systems for the De Novo Rescue of Diverse Members of Paramyxoviridae

Paramyxoviruses place significant burdens on both human and wildlife health; while some paramyxoviruses are established within human populations, others circulate within diverse animal reservoirs. Concerningly, bat-borne paramyxoviruses have spilled over into humans with increasing frequency in recent years, resulting in severe disease. The risk of future zoonotic outbreaks, as well as the persistence of paramyxoviruses that currently circulate within humans, highlights the need for efficient tools through which to interrogate paramyxovirus biology. Reverse genetics systems provide scientists with the ability to rescue paramyxoviruses de novo, offering versatile tools for implementation in both research and public health settings. Reverse genetics systems have greatly improved over the past 30 years, with several key innovations optimizing the success of paramyxovirus rescue. Here, we describe the significance of such advances and provide a generally applicable guide for the development and use of reverse genetics systems for the rescue of diverse members of Paramyxoviridae.

Combined oncolytic virotherapy gold nanoparticles as synergistic immunotherapy agent in breast cancer control

Combining viruses and nanoparticles may be a way to successfully treat cancer and minimize adverse effects. The current work aimed to evaluate the efficacy of a specific combination of gold nanoparticles (GNPs) and Newcastle disease virus (NDV) to enhance the antitumor effect of breast cancer in both in vitro and in vivo models. Two human breast cancer cell lines (MCF-7 and AMJ-13) and a normal epithelial cell line (HBL-100) were used and treated with NDV and/or GNPs. The MTT assay was used to study the anticancer potentials of NDV and GNP. The colony formation assay and apoptosis markers were used to confirm the killing mechanisms of NDV and GNP against breast cancer cell lines. p53 and caspase-9 expression tested by the qRT-PCR technique. Our results showed that combination therapy had a significant killing effect against breast cancer cells. The findings demonstrated that NDV and GNPs induced apoptosis in cancer cells by activating caspase-9, the p53 protein, and other proteins related to apoptosis, which holds promise as a combination therapy for breast cancer.

Papaverine Enhances the Oncolytic Effects of Newcastle Disease Virus on Breast Cancer In Vitro and In Vivo

Breast cancer is a lethal disease in females worldwide and needs effective treatment. Targeting cancer cells with selective and safe treatment seems like the best choice, as most chemotherapeutic drugs act unselectively. Papaverine showed promising antitumor activity with a high safety profile and increased blood flow through vasodilation. At the same time, it was widely noticed that virotherapy using the Newcastle disease virus proved to be safe and selective against a broad range of cancer cells. Furthermore, combination therapy is favorable, as it attacks cancer cells with multiple mechanisms and enhances virus entrance into the tumor mass, overcoming cancer cells' resistance to therapy. Therefore, we aimed at assessing the novel combination of the AMHA1 strain of Newcastle disease virus (NDV) and nonnarcotic opium alkaloid (papaverine) against breast cancer models in vitro and in vivo. Methods. In vitro experiments used two human breast cancer cell lines and one normal cell line and were treated with NDV, papaverine, and a combination. The study included a cell viability MTT assay, morphological analysis, and apoptosis detection. Animal experiments used the AN3 mouse mammary adenocarcinoma tumor model. Evaluation of the antitumor activity included growth inhibition measurement; the immunohistochemistry assay measured caspase protein expression. Finally, a semiquantitative microarray assay was used to screen changes in apoptotic proteins. In vitro, results showed that the combination therapy induces synergistic cytotoxicity and apoptosis against cancer cells with a negligible cytotoxic effect on normal cells. In vivo, combination treatment induced a significant antitumor effect with an obvious regression in tumor size and a remarkable and significant expression of caspase-3, caspase-8, and caspase-9 compared to monotherapies. Microarray analysis shows higher apoptosis protein levels in the combination therapy group. In conclusion, this study demonstrated the role of papaverine in enhancing the antitumor activity of NDV, suggesting a promising strategy for breast cancer therapy through nonchemotherapeutic drugs.

Newcastle disease virus LaSota strain induces apoptosis and activates the TNFα/NF-κB pathway in canine mammary carcinoma cells

Spontaneous canine mammary carcinomas (CMCs) have been widely considered a good research model for human breast cancers, which brings much attention to CMCs. In recent years, the oncolytic effect of Newcastle disease virus (NDV) on cancer cells has been widely studied, but its effect on CMCs is still unclear. This study aims to investigate the oncolytic effect of NDV LaSota strain on canine mammary carcinoma cell line (CMT-U27) in vivo and in vitro. The in vitro cytotoxicity and immunocytochemistry experiments showed that NDV selectively replicated in CMT-U27 cells, and inhibited cell proliferation and migration but not in MDCK cells. KEGG analysis of transcriptome sequencing indicated the importance of the TNFα and NF-κB signalling pathways in the anti-tumour effect of NDV. Subsequently, the significantly increased expression of TNFα, p65, phospho-p65, caspase-8, caspase-3 and cleaved-PARP proteins in the NDV group suggested that NDV induced CMT-U27 cells apoptosis by activating the caspase-8/caspase-3 pathway and the TNFα/NF-κB signalling pathway. Nude mice tumour-bearing experiments showed that NDV could significantly decrease the growth rate of CMC in vivo. In conclusion, our study demonstrates the effective oncolytic effects of NDV on CMT-U27 cells in vivo and in vitro, and suggests NDV as a promising candidate for oncolytic therapy.

The Viral Knock: Ameliorating Cancer Treatment with Oncolytic Newcastle Disease Virus

The prospect of cancer treatment has drastically transformed over the last four decades. The side effects caused by the traditional methods of cancer treatment like surgery, chemotherapy, and radiotherapy through the years highlight the prospect for a novel, complementary, and alternative cancer therapy. Oncolytic virotherapy is an evolving treatment modality that utilizes oncolytic viruses (OVs) to selectively attack cancer cells by direct lysis and can also elicit a strong anti-cancer immune response. Newcastle disease virus (NDV) provides a very high safety profile compared to other oncolytic viruses. Extensive research worldwide concentrates on experimenting with and better understanding the underlying mechanisms by which oncolytic NDV can be effectively applied to intercept cancer. This review encapsulates the potential of NDV to be explored as an oncolytic agent and discusses current preclinical and clinical research scenarios involving various NDV strains.

Analysis of PPI networks of transcriptomic expression identifies hub genes associated with Newcastle disease virus persistent infection in bladder cancer

Bladder cancer cells can acquire persistent infection of oncolytic Newcastle disease virus (NDV) but the molecular mechanism(s) remain unelucidated. This poses a major barrier to the effective clinical translation of oncolytic NDV virotherapy of cancers. To improve our understanding of the molecular mechanism(s) associated with the development of NDV persistent infection in bladder cancer, we used mRNA expression profiles of persistently infected bladder cancer cells to construct PPI networks. Based on paths and modules in the PPI network, the bridges were found mainly in the upregulated mRNA-pathways of p53 signalling, ECM-receptor interaction, and TGF-beta signalling and downregulated mRNA-pathways of antigen processing and presentation, protein processing in endoplasmic reticulum, completement and coagulation cascades in persistent TCCSUPPi cells. In persistent EJ28Pi cells, connections were identified mainly through upregulated mRNA-pathways of renal carcinoma, viral carcinogenesis, Ras signalling and cell cycle and the downregulated mRNA-pathways of Wnt signalling, HTLV-I infection and pathways in cancers. These connections were mainly dependent on RPL8-HSPA1A/HSPA4 in TCCSUPPi cells and EP300, PTPN11, RAC1-TP53, SP1, CCND1 and XPO1 in EJ28Pi cells. Oncomine validation showed that the top hub genes identified in the networks that include RPL8, THBS1, F2 from TCCSUPPi and TP53 and RAC1 from EJ28Pi are involved in the development and progression of bladder cancer. Protein-drug interaction networks identified several putative drug targets that could be used to disrupt the linkages between the modules and prevent bladder cancer cells from acquiring NDV persistent infection. This novel PPI network analysis of differentially expressed mRNAs of NDV persistently infected bladder cancer cell lines provide an insight into the molecular mechanisms of NDV persistency of infection in bladder cancers and the future screening of drugs that can be used together with NDV to enhance its oncolytic efficacy.

The V protein in oncolytic Newcastle disease virus promotes HepG2 hepatoma cell proliferation at the single-cell level

BACKGROUND

Newcastle disease virus (NDV) is an oncolytic virus that can inhibit cancer cell proliferation and kill cancer cells. The NDV nonstructural V protein can regulate viral replication; however, whether the V protein contributes to NDV oncolysis is unclear.

RESULTS

This study revealed that NDV inhibited tumor cell proliferation and that V protein expression promoted the proliferation of HepG2 cells, as determined at the single-cell level. In addition, to identify the regulatory mechanism of the V protein in HepG2 cells, transcriptome sequencing was performed and indicated that the expression/activation of multiple cell proliferation-related genes/signaling pathways were changed in cells overexpressing the V protein. Hence, the MAPK and WNT signaling pathways were selected for verification, and after blocking these two signaling pathways with inhibitors, the V protein promotion of cell proliferation was found to be attenuated.

CONCLUSIONS

The results showed that the V protein regulated the proliferation of cancer cells through multiple signaling pathways, providing valuable references for future studies on the mechanism by which the V protein regulates cancer cell proliferation.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

Investigation of oncolytic effect of recombinant Newcastle disease virus in primary and metastatic oral melanoma

Malignant melanoma is aggressive cancer with a high rate of local invasiveness and metastasis. Currently, the treatment options for patients with advanced-stage and metastatic oral melanoma are limited. A promising treatment option is oncolytic viral therapy. This study aimed to evaluate novel therapies for malignant melanoma using a canine model. Oral melanoma, which frequently occurs in dogs is used as a model for human melanoma, was isolated and cultured and used for the evaluation of the tumor lytic effect induced by viral infection. We constructed a recombinant Newcastle disease virus (rNDV) that promotes the extracellular release of IFNγ from the virus-infected melanoma. The expression of oncolytic and apoptosis-related genes, the immune response by lymphocytes, and IFNγ expression were evaluated in virus-infected melanoma cells. The results showed that the rate of rNDV infection varied according to the isolated melanoma cells and the oncolytic effect differed between melanoma cells owing to the infectivity of the virus. The oncolytic effect tended to be greater for the IFNγ-expressing virus than for the GFP-expressing prototype virus. Additionally, lymphocytes co-cultured with the virus showed induced expression of Th1 cytokines. Therefore, recombinant NDV expressing IFNγ is expected to induce cellular immunity and oncolytic activity. This oncolytic treatment shows promise as a therapeutic approach for melanoma treatment once evaluated using clinical samples from humans.

Nano Based-Oncolytic viruses for Cancer therapy

Oncolytic viruses (OV) are an attractive prospect due to their dual attack mechanism of direct cell lysis and potentiation of an antitumor immune response. Various oncolytic viral vectors are used in oncotherapy clinical trials, and one of their main problems is elimination by the reticuloendothelial system during systemic delivery. Nanoparticles (NPs) have received much attention in clinical trials due to their unique appearance characteristics, but they have created challenges due to the non-specificity of drug delivery to the target tissue and its elimination in blood circulation. In this regard, to increase the efficiency of nanoparticles in drug delivery, various chemical modifications can be applied to the surface of nanoparticles. To improve the performance of these two treatment options, the complex strategy of OVs encapsulated with nanoparticles can be used, which has brought successful clinical results in the treatment of various cancers. Here we will review each of the treatment methods and their functional mechanism.

Inhibition of Tumor Growth and Metastasis by Newcastle Disease Virus Strain P05 in a Breast Cancer Mouse Model

PURPOSE

Conventional therapies and surgery remain the standard treatment for breast cancer. However, combating the eventual development of metastasis is still a challenge. Newcastle disease virus (NDV) is one of the various species of viruses under clinical evaluation as a vector for oncolytic, gene-, and immune-stimulating therapies. The purpose of this study was to evaluate the antitumor activity of a recombinant NDV (rNDV-P05) in a breast cancer murine model.

METHODS

Tumors were induced by injecting the cellular suspension (4T1 cell line) subcutaneously. The virus strain P05 was applied three times at intervals of seven days, starting seven days after tumor induction, and was completed 21 days later. Determination of tumor weight, spleen index, and lung metastasis were done after sacrificing the mice. Serum levels of interferon (IFN)-α, IFN-γ, tumor necrosis factor (TNF)-α, and TNF-related apoptosis-inducing ligand (TRAIL) were quantified by enzyme-linked immunosorbent assay. CD8+ infiltrated cells were analyzed by immunofluorescence.

RESULTS

rNDV-P05 showed a route-of-administration-dependent effect, demonstrating that the systemic administration of the virus significantly reduces the tumor mass and volume, spleen index, and abundance of metastatic clonogenic colonies in lung tissue, and increases the inhibition rate of the tumor. The intratumoral administration of rNDV-P05 was ineffective for all the parameters evaluated. Antitumor and antimetastatic capability of rNDV-P05 is mediated, at least partially, through its immune-stimulatory effect on the upregulation of TNF-α, TRAIL, IFN-α, and IFN-γ, and its ability to recruit CD8+ T cells into tumor tissue.

CONCLUSION

Systemic treatment with rNDV-P05 decreases the tumoral parameters in the breast cancer murine model.

Emerging Nano-/Biotechnology Drives Oncolytic Virus-Activated and Combined Cancer Immunotherapy

Oncolytic viruses (OVs) as one promising antitumor methods have made important contributions to tumor immunotherapy, which arouse increasing attention. They provide the dual mechanisms including direct killing effect toward tumor cells and immune activation for elevating antitumor responses, which have been proved in many preclinical studies. Especially, natural or genetically modified viruses as clinical immune preparations have emerged as a new promising approach objective to oncology treatment. The approval of talimogene laherparepvec (T-VEC) by the U.S. Food and Drug Administration (FDA) for the therapy of advanced melanoma could be considered as a milestone achievement in the clinical translation of OV. In this review, we first discussed the antitumor mechanisms of OVs with an emphasis on targeting, replication, and propagation. We further outlined the state of the art of current OVs in tumor and underlined the activated biological effects especially including immunity. More significantly, the enhanced immune responses based on OVs were systematically discussed from different perspectives such as combination with immunotherapy, genetic engineering of OVs, integration with nanobiotechnology or nanoparticles, and antiviral response counteraction, where their principles were shed light on. The development of OVs in the clinics was also highlighted to analyze the actuality and concerns of different OV applications in clinical trials. At last, the future perspectives and challenges of OVs as an already widely accepted treatment means were discussed. This review will provide a systematic review and deep insight into OV development and also offer new opportunities and guidance pathways to drive the further clinical translation.

Gospel of malignant Glioma: Oncolytic virus therapy

Glioma accounts for nearly 80% of all intracranial malignant tumors. It is a major challenge to society as it is causes to impaired brain function in many patients. Currently, gliomas are mainly treated with surgery, postoperative radiotherapy, and chemotherapy. However, the curative effects of these treatments are not satisfactory. Oncolytic virus (OV) is a novel treatment which works by activating the immune functions and inducing apoptosis of tumor cells. The OV propagates indefinitely in the host cell, eventually leading to the death of host cell. Subsequently, a large number of antigens and signal molecules are released which exert antitumor immunity. Several preclinical and clinical studies have shown that G207, DNX2401, Zika and other viruses have important roles in malignant tumors. For example, these viruses can reduce the growth of tumor cells without causing severe complications. However, the known OVs have not been clearly classified. Herein, we divided OVs into neurotropic and non-neurophilic OVs based on whether the OVs are naturally neurotropic or not. The therapeutic effects of each group were compared. Finally, challenges encountered in the clinical application of OVs in the treatment of malignant gliomas were summarized.

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.

Optimizing environmental safety and cell-killing potential of oncolytic Newcastle Disease virus with modifications of the V, F and HN genes

Newcastle Disease Virus (NDV) is an avian RNA virus, which was shown to be effective and safe for use in oncolytic viral therapy for several tumour malignancies. The presence of a multi basic cleavage site (MBCS) in the fusion protein improved its oncolytic efficacy in vitro and in vivo. However, NDV with a MBCS can be virulent in poultry. We aimed to develop an NDV with a MBCS but with reduced virulence for poultry while remaining effective in killing human tumour cells. To this end, the open reading frame of the V protein, an avian specific type I interferon antagonist, was disrupted by introducing multiple mutations. NDV with a mutated V gene was attenuated in avian cells and chicken and duck eggs. Although this virus still killed tumour cells, the efficacy was reduced compared to the virulent NDV. Introduction of various mutations in the fusion (F) and hemagglutinin-neuraminidase (HN) genes slightly improved this efficacy. Taken together, these data demonstrated that NDV with a MBCS but with abrogation of the V protein ORF and mutations in the F and HN genes can be safe for evaluation in oncolytic viral therapy.

Autophagy Modulation by Viral Infections Influences Tumor Development

Autophagy is a self-degradative process important for balancing cellular homeostasis at critical times in development and/or in response to nutrient stress. This is particularly relevant in tumor model in which autophagy has been demonstrated to have an important impact on tumor behavior. In one hand, autophagy limits tumor transformation of precancerous cells in early stage, and in the other hand, it favors the survival, proliferation, metastasis, and resistance to antitumor therapies in more advanced tumors. This catabolic machinery can be induced by an important variety of extra- and intracellular stimuli. For instance, viral infection has often been associated to autophagic modulation, and the role of autophagy in virus replication differs according to the virus studied. In the context of tumor development, virus-modulated autophagy can have an important impact on tumor cells' fate. Extensive analyses have shed light on the molecular and/or functional complex mechanisms by which virus-modulated autophagy influences precancerous or tumor cell development. This review includes an overview of discoveries describing the repercussions of an autophagy perturbation during viral infections on tumor behavior.

Evaluation of the oncolytic property of recombinant Newcastle disease virus strain R2B in 4T1 and B16-F10 cells in-vitro

Recombinant Newcastle disease virus vectors have gained a lot of interest for its oncolytic virus therapy and cancer immune therapeutic properties due to its selective replication to high titers in cancer cells. The aim of this study was to find out the oncolytic effects of mesogenic recombinant NDV strain R2B-GFP on murine mammary tumor cell line 4T1 and murine melanoma cell line B16-F10. The anti-tumor effects of R2B-GFP virus were studied via expression of virus transgene GFP in cancer cells, evaluating its cytotoxicity and cell migration efficacies by MTT and wound healing assays respectively. In addition, the underlying apoptotic mechanism of R2B-GFP virus was estimated by TUNEL assay, colorimetric estimation of Caspase-3, 8 and 9 and the estimation of Bax to Bcl-2 ratio. The results showed a significant decrease in viability of both 4T1 and B16-F10 cells infected with R2B-GFP virus at 0.1 and 1 MOI. R2B-GFP virus could significantly induce apoptosis in the 4T1 and B16-F10 cells as compared to the uninfected control. Further, a flow cytometry analysis on apoptotic cells percentage and mitochondria membrane permeability test was also studied in R2B-GFP virus treated 4T1 and B16-F10 cell lines. The R2B-GFP virus caused an increase in loss of mitochondrial membrane permeability in both 4T1 and B16-F10 cells indicating the involvement of mitochondrial regulated cell death. Thus, the recombinant virus R2B-GFP virus proved to be a valid candidate for oncolytic viral therapy in 4T1 and B16-F10 cells.

Antitumor immunity enhancement through Newcastle viral oncolysate in mice model: A promising method to treat tumors

A Newcastle disease virus (NDV) oncolysate has been established as a unique and effective immune-stimulatory root for tumor treatment. Thus, the aim of the current study was to investigate the effects of intratumoral administration of NDV oncolysate on immune response and tumor regression of C57BL/6 mouse model of human papillomavirus (HPV) related transplanted with TC-1 syngeneic cancer cells. To further investigate the mechanism underlying the antitumor response, cytolytic and lymphocyte proliferation responses in splenocytes were measured using lactate dehydrogenase (LDH) release and MTT assays, respectively. In this regard, levels of IL-10, IFN-γ, and IL-4 were measured using ELISA after re-stimulation. The immune responses efficacy was evaluated by in vivo tumor regression assay. The results showed that immunization with the different titers of NDV lysate significantly reduced tumor volume in comparison with a combination of virus lysate and tumor cell lysate. Also, virus lysate could significantly enhance cytotoxic T lymphocyte production and lymphocyte proliferation rates versus tumor cell lysate. Also, our major findings are that the peritumorally injection of NDV oncolysate effectively induces antitumor immune responses through increased levels of IL-4, IFN-γ, and reduction of IL-10. These results indicate that this treatment is a specific, active immune mechanism stimulator, and may prove to be a useful therapeutic for a treatment against cervical cancers and merits further investigation.

Persistent Newcastle disease virus infection in bladder cancer cells is associated with putative pro-survival and anti-viral transcriptomic changes

Background

Newcastle disease virus (NDV) is an oncolytic virus with excellent selectivity against cancer cells, both in vitro and in vivo. Unfortunately, prolonged in vitro NDV infection results in the development of persistent infection in the cancer cells which are then able to resist NDV-mediated oncolysis. However, the mechanism of persistency of infection remains poorly understood.

Methods

In this study, we established persistently NDV-infected EJ28 bladder cancer cells, designated as EJ28P. Global transcriptomic analysis was subsequently carried out by microarray analysis. Differentially expressed genes (DEGs) between EJ28 and EJ28P cells identified by the edgeR program were further analysed by Gene Set Enrichment Analysis (GSEA) and Ingenuity Pathway Analysis (IPA) analyses. In addition, the microarray data were validated by RT-qPCR.

Results

Persistently NDV-infected EJ28 bladder cancer cells were successfully established and confirmed by flow cytometry. Microarray analysis identified a total of 368 genes as differentially expressed in EJ28P cells when compared to the non-infected EJ28 cells. GSEA revealed that the Wnt/β-catenin and KRAS signalling pathways were upregulated while the TGF-β signalling pathway was downregulated. Findings from this study suggest that the upregulation of genes that are associated with cell growth, pro-survival, and anti-apoptosis may explain the survivability of EJ28P cells and the development of persistent infection of NDV.

Conclusions

This study provides insights into the transcriptomic changes that occur and the specific signalling pathways that are potentially involved in the development and maintenance of NDV persistency of infection in bladder cancer cells. These findings warrant further investigation and is crucial towards the development of effective NDV oncolytic therapy against cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08345-y.

Mechanisms and consequences of Newcastle disease virus W protein subcellular localization in the nucleus or mitochondria

We previously demonstrated that W proteins from different Newcastle disease virus (NDV) strains localize in either the cytoplasm (e.g., NDV strain SG10) or the nucleus (e.g., NDV strain La Sota). To clarify the mechanism behind these cell localization differences, we overexpressed W protein derived from four different NDV strains or W protein associated with different cellular regions in Vero cells. This revealed that the key region for determining W protein localization is 180-227aa. Further experiments found that there is a nuclear export signal (NES) motif in W protein 211-224aa. W protein could be transported into the nucleus via interaction with KPNA1, KPNA2, and KPNA6 in a nuclear localization signal-dependent manner, and W protein containing an NES was transported back to the cytoplasm in a CRM1-independent manner. Interestingly, we observed that the cytoplasm-localized W protein colocalizes with mitochondria. We rescued the NES-deletion W protein NDV strain rSG10-ΔW_C/W_ΔNES using an NDV reverse genetics system and found that the replication ability, virulence, and pathogenicity of an NDV strain were all higher when the W protein cellular localization was in the nucleus rather than the mitochondria. Further experiments revealed that W protein nuclear localization reduced the expression of IFN-β otherwise stimulated by NDV. Our research reveals the mechanism by which NDV W protein becomes localized to different parts of the cell and demonstrates the outcomes of nuclear or cytoplasmic localization both in vitro and in vivo, laying a foundation for subsequent functional studies of the W protein in NDV and other paramyxoviruses.IMPORTANCE In Newcastle disease virus (NDV), the W protein, like the V protein, is a nonstructural protein encoded by the P gene via RNA editing. Compared with V protein, W protein has a common N-terminal domain but a unique C-terminal domain. V protein is known as a key virulence factor and an important interferon antagonist across the family Paramyxoviridae In contrast, very little is known about the function of NDV W protein, and this limited information is based on studies of the Nipah virus W protein. Here, we investigated the localization mechanism of NDV W protein and its subcellular distribution in mitochondria. We found that W protein localization differences impact IFN-β production, consequently affecting NDV virulence, replication, and pathogenicity. This work provides new insights on the differential localization mechanism of NDV W proteins, along with fundamental knowledge for understanding the functions of W proteins in NDV and other paramyxoviruses.

The oncolytic Newcastle disease virus as an effective immunotherapeutic strategy against glioblastoma

Glioblastoma is the most frequent primary brain tumor in adults, with a dismal prognosis despite aggressive resection, chemotherapeutics, and radiotherapy. Although understanding of the molecular pathogenesis of glioblastoma has progressed in recent years, therapeutic options have failed to significantly change overall survival or progression-free survival. Thus, researchers have begun to explore immunomodulation as a potential strategy to improve clinical outcomes. The application of oncolytic virotherapy as a novel biological to target pathogenic signaling in glioblastoma has brought new hope to the field of neuro-oncology. This class of immunotherapeutics combines selective cancer cell lysis prompted by virus induction while promoting a strong inflammatory antitumor response, thereby acting as an effective in situ tumor vaccine. Several investigators have reported the efficacy of experimental oncolytic viruses as demonstrated by improved long-term survival in cancer patients with advanced disease. Newcastle disease virus (NDV) is one of the most well-researched oncolytic viruses known to affect a multitude of human cancers, including glioblastoma. Preclinical in vitro and in vivo studies as well as human clinical trials have demonstrated that NDV exhibits oncolytic activity against glioblastoma, providing a promising avenue of potential treatment. Herein, the authors provide a detailed discussion on NDV as a mode of therapy for glioblastoma. They discuss the potential therapeutic pathways associated with NDV as demonstrated by in vitro and in vivo experiments as well as results from human trials. Moreover, they discuss current challenges, potential solutions, and future perspectives in utilizing NDV in the treatment of glioblastoma.

Combining vanadyl sulfate with Newcastle disease virus potentiates rapid innate immune-mediated regression with curative potential in murine cancer models

The avian paramyxovirus, Newcastle disease virus (NDV), is a promising oncolytic agent that has been shown to be safe and effective in a variety of pre-clinical cancer models and human clinical trials. NDV preferentially replicates in tumor cells due to signaling defects in apoptotic and antiviral pathways acquired during the transformation process and is a potent immunostimulatory agent. However, when used as a monotherapy NDV lacks the ability to consistently generate durable remissions. Here we investigate the use of viral sensitizer-mediated combination therapy to enhance the anti-neoplastic efficacy of NDV. Intratumoral injection of vanadyl sulfate, a pan-inhibitor of protein tyrosine phosphatases, in combination with NDV significantly increased the number and activation status of natural killer (NK) cells in the tumor microenvironment, concomitant with increased expression of interferon-β, granulocyte-macrophage colony-stimulating factor, and monocyte chemoattractant protein-1, leading to rapid tumor regression and long-term cures in mice bearing syngeneic B16-F10 melanomas. The anti-tumor efficacy of this combination therapy was abrogated when NK cells were depleted and when interferon-β expression was transiently suppressed. Tumor-specific CD8⁺ T cell responses were not detected, nor were mice whose tumors regressed protected from re-challenge. This suggested efficacy of the combination therapy predominantly relied on the innate immune system. Importantly, efficacy was not limited to melanoma; it was also demonstrated in a murine prostate cancer model. Taken together, these results suggest that combining NDV with vanadyl sulfate potentiates an innate immune response that can potentiate rapid clearance of tumors, with type I interferon signaling and NK cells being important mechanisms of action.

Newcastle Disease Virus at the Forefront of Cancer Immunotherapy

Preclinical and clinical studies dating back to the 1950s have demonstrated that Newcastle disease virus (NDV) has oncolytic properties and can potently stimulate antitumor immune responses. NDV selectively infects, replicates within, and lyses cancer cells by exploiting defective antiviral defenses in cancer cells. Inflammation within the tumor microenvironment in response to NDV leads to the recruitment of innate and adaptive immune effector cells, presentation of tumor antigens, and induction of immune checkpoints. In animal models, intratumoral injection of NDV results in T cell infiltration of both local and distant non-injected tumors, demonstrating the potential of NDV to activate systemic adaptive antitumor immunity. The combination of intratumoral NDV with systemic immune checkpoint blockade leads to regression of both injected and distant tumors, an effect further potentiated by introduction of immunomodulatory transgenes into the viral genome. Clinical trials with naturally occurring NDV administered intravenously demonstrated durable responses across numerous cancer types. Based on these studies, further exploration of NDV is warranted, and clinical studies using recombinant NDV in combination with immune checkpoint blockade have been initiated.

NDV-D90 inhibits 17β-estradiol-mediated resistance to apoptosis by differentially modulating classic and nonclassic estrogen receptors in breast cancer cells

Newcastle disease virus (NDV) is endowed with the oncolytic ability to kill tumor cells, while rarely causing side effects in normal cells. Both estrogen receptor α (ERα) and the G protein estrogen receptor (GPER) modulate multiple biological activities in response to estrogen, including apoptosis in breast cancer (BC) cells. Here, we investigated whether NDV-D90, a novel strain isolated from natural sources in China, promoted apoptosis by modulating the expression of ERα or the GPER in BC cells exposed to 17β-estradiol (E2). We found that NDV-D90 significantly killed the tumor cell lines MCF-7 and BT549 in a time- and dose-dependent manner. We also found that NDV-D90 exerted its effects on the two cell lines mainly by inducing apoptosis but not necrosis. NDV-D90 induced apoptosis via the intrinsic and extrinsic signaling pathways in MCF-7 cells (ER-positive cells) during E2 exposure not only by disrupting the E2/ERα axis and enhancing GPER expression but also by modulating the expression of several apoptosis-related proteins through ERα-and GPER-independent processes. NDV-D90 promoted apoptosis via the intrinsic signaling pathway in BT549 cells (ER-negative cells), possibly by impairing E2-mediated GPER expression. Furthermore, NDV-D90 exerted its antitumor effects in vivo by inducing apoptosis. Overall, these results demonstrated that NDV-D90 promotes apoptosis by differentially modulating the expression of ERα and the GPER in ER-positive and negative BC cells exposed to estrogen, respectively, and can be utilized as an effective approach to treating BC.

Newcastle disease virus suppress glycolysis pathway and induce breast cancer cells death

Newcastle disease virus (NDV) can modulate cancer cell signaling pathway and induce apoptosis in cancer cells. Cancer cells increase their glycolysis rates to meet the energy demands for their survival and generate ATP as the primary energy source for cell growth and proliferation. Interfering the glycolysis pathway may be a valuable antitumor strategy. This study aimed to assess the effect of NDV on the glycolysis pathway in infected breast cancer cells. Oncolytic NDV attenuated AMHA1 strain was used in this study. AMJ13 and MCF7 breast cancer cell lines and a normal embryonic REF cell line were infected with NDV with different multiplicity of infections (moi) to determine the IC50 of NDV through MTT assay. Crystal violet staining was done to study the morphological changes. NDV apoptosis induction was assessed using AO/PI assay. NDV interference with the glycolysis pathway was examined through measuring hexokinase (HK) activity, pyruvate, and ATP concentrations, and pH levels in NDV infected and non-infected breast cancer cells and in normal embryonic cells. The results showed that NDV replicates efficiently in cancer cells and spare normal cells and induce morphological changes and apoptosis in breast cancer cells but not in normal cells. NDV infected cancer cells showed decreased in the HK activity, pyruvate and ATP concentrations, and acidity, which reflect a significant decrease in the glycolysis activity of the NDV infected tumor cells. No effects on the normal cells were observed. In conclusion, oncolytic NDV ability to reduce glycolysis pathway activity in cancer cells can be an exciting module to improve antitumor therapeutics.

Synergy between hemagglutinin 2 (HA2) subunit of influenza fusogenic membrane glycoprotein and oncolytic Newcastle disease virus suppressed tumor growth and further enhanced by Immune checkpoint PD-1 blockade

Background

Newcastle disease virus (NDV) has shown noticeable oncolytic properties, especially against cervical cancer. However, in order to improve the spread rate and oncotoxicity of the virus, employment of other therapeutic reagents would be helpful. It has been shown that some viral fusogenic membrane glycoproteins (FMGs) could facilitate viral propagation and increase the infection rate of tumor cells by oncolytic viruses. Additionally, immune checkpoint blockade has widely been investigated for its anti-tumor effects against several types of cancers. Here, we investigated for the first time whether the incorporation of influenza hemagglutinin-2 (HA2) FMG could improve the oncolytic characteristics of NDV against cervical cancer. Next, we added anti-PD-1 mAb to our therapeutic recipe to assess the complementary role of immune checkpoint blockade in curbing tumor progression.

Methods

For this purpose, TC-1 tumor cells were injected into the mice models and treatment with NDV, iNDV, HA2, NDV-HA2, iNDV-HA2 began 10 days after tumor challenge and was repeated at day 17. In addition, PD-1 blockade was conducted by injection of anti-PD-1 mAb at days 9 and 16. Two weeks after the last treatment, sample mice were sacrificed and treatment efficacy was evaluated through immunological and immunohistochemical analysis. Moreover, tumors condition was monitored weekly for 6 weeks intervals and the tumor volume was measured and compared within different groups.

Results

The results of co-treatment with NDV and HA2 gene revealed that these agents act synergistically to induce antitumor immune responses against HPV-associated carcinoma by enhancement of E7-specific lymphocyte proliferation, inducement of CD8⁺ T cell cytotoxicity responses, increase in splenic cytokines and granzyme B, decrease in immunosuppressive cytokines and E6 oncogene expression, and upregulation of apoptotic proteins expression, in comparison with control groups. Moreover, incorporation of PD-1 blockade as the third side of our suggested therapy led to noticeable regression in tumor size and augmentation of cytokine responses.

Conclusions

The invaluable results of synergy between NDV virotherapy and HA2 gene therapy suggest that tumor-selective cell killing by oncolytic NDV can be enhanced by combining with FMG gene therapy. Moreover, the adjunction of the PD-1 blockade proves that checkpoint blockade can be considered as an effective complementary therapy for the treatment of cervical cancer.

Oncolytic effects of Hitchner B1 strain of newcastle disease virus against cervical cancer cell proliferation is mediated by the increased expression of cytochrome C, autophagy and apoptotic pathways

Newcastle disease virus (NDV) is a potential oncolytic virus for the cancer treatment due to its ability to replicate in tumor cells. The aim of this study was to evaluate the in vitro anticancer properties of Hitchner B1 (HB1) strain of NDV on TC-1 cell line and underlying molecular mechanisms. The cytolytic effects of oncolytic HB1 strain of NDV was determined by lactate dehydrogenase (LDH) release assay. Apoptosis, intracellular reactive oxygen species (ROS) levels, cleaved caspase-3 and autophagy were evaluated by flow cytometry. Cytochrome-C and survivin protein levels were distinguished by Enzyme-Linked Immunosorbent Assay (ELISA). Our results from LDH method showed that the viability of the TC-1 cell line following HB1 NDV infection was dose-dependent and decreased significantly with increasing the dose of HB1 NDV infection (MOIs: 5, 10, and 15). Other evaluations also revealed that HB1 strain of NDV potentially led to the ROS production, and apoptosis and autophagy induction in TC-1 cell line in a dose-dependent manner. The in vitro experiments also presented that NDV treatment significantly up-regulated the expression of cytochrome-C and down-regulated the expression of survivin, as detected by ELISA assay. Our results confirmed that the HB1 NDV could be introduced as a powerful candidate for the therapy of cervical cancer. However, further examinations are needed to explain the underlying mechanisms of the HB1 NDV against TC-1 cell line and cervical cancer.

ATM-mediated DNA double-strand break response facilitated oncolytic Newcastle disease virus replication and promoted syncytium formation in tumor cells

Deoxyribonucleic acid (DNA) damage response (DDR) is the fundamental cellular response for maintaining genomic integrity and suppressing tumorigenesis. The activation of ataxia telangiectasia-mutated (ATM) kinase is central to DNA double-strand break (DSB) for maintaining host-genome integrity in mammalian cells. Oncolytic Newcastle disease virus (NDV) can selectively replicate in tumor cells; however, its influence on the genome integrity of tumor cells is not well-elucidated. Here, we found that membrane fusion and NDV infection triggered DSBs in tumor cells. The late replication and membrane fusion of NDV mechanistically activated the ATM-mediated DSB pathway via the ATM-Chk2 axis, as evidenced by the hallmarks of DSBs, i.e., auto-phosphorylated ATM and phosphorylated H2AX and Chk2. Immunofluorescence data showed that multifaceted ATM-controlled phosphorylation markedly induced the formation of pan-nuclear punctum foci in response to NDV infection and F-HN co-expression. Specific drug-inhibitory experiments on ATM kinase activity further suggested that ATM-mediated DSBs facilitated NDV replication and membrane fusion. We confirmed that the Mre11-RAD50-NBS1 (MRN) complex sensed the DSB signal activation triggered by NDV infection and membrane fusion. The pharmacological inhibition of MRN activity also significantly inhibited intracellular and extracellular NDV replication and syncytia formation. Collectively, these data identified for the first time a direct link between the membrane fusion induced by virus infection and DDR pathways, thereby providing new insights into the efficient replication of oncolytic NDV in tumor cells.

Exploring the Prospects of Engineered Newcastle Disease Virus in Modern Vaccinology

Many traditional vaccines have proven to be incapable of controlling newly emerging infectious diseases. They have also achieved limited success in the fight against a variety of human cancers. Thus, innovative vaccine strategies are highly needed to overcome the global burden of these diseases. Advances in molecular biology and reverse genetics have completely restructured the concept of vaccinology, leading to the emergence of state-of-the-art technologies for vaccine design, development and delivery. Among these modern vaccine technologies are the recombinant viral vectored vaccines, which are known for their incredible specificity in antigen delivery as well as the induction of robust immune responses in the vaccinated hosts. Although a number of viruses have been used as vaccine vectors, genetically engineered Newcastle disease virus (NDV) possesses some useful attributes that make it a preferable candidate for vectoring vaccine antigens. Here, we review the molecular biology of NDV and discuss the reverse genetics approaches used to engineer the virus into an efficient vaccine vector. We then discuss the prospects of the engineered virus as an efficient vehicle of vaccines against cancer and several infectious diseases of man and animals.

Syncytia Formation in Oncolytic Virotherapy

Oncolytic virotherapy uses replication-competent virus as a means of treating cancer. Whereas this field has shown great promise as a viable treatment method, the limited spread of these viruses throughout the tumor microenvironment remains a major challenge. To overcome this issue, researchers have begun looking at syncytia formation as a novel method of increasing viral spread. Several naturally occurring fusogenic viruses have been shown to possess strong oncolytic potential and have since been studied to gain insight into how this process benefits oncolytic virotherapy. Whereas these naturally fusogenic viruses have been beneficial, there are still challenges associated with their regular use. Because of this, engineered/recombinant fusogenic viruses have also been created that enhance nonfusogenic oncolytic viruses with the beneficial property of syncytia formation. The purpose of this review is to examine the existing body of literature on syncytia formation in oncolytics and offer direction for potential future studies.

eIF2α-CHOP-BCl-2/JNK and IRE1α-XBP1/JNK signaling promote apoptosis and inflammation and support the proliferation of Newcastle disease virus

Newcastle disease virus (NDV) causes severe infectious disease in poultry and selectively kills tumor cells, by inducing apoptosis and cytokines secretion. In this report, we study the mechanisms underlying NDV-induced apoptosis by investigating the unfolded protein response (UPR). We found that NDV infection activated all three branches of the UPR signaling (PERK-eIF2α, ATF6, and IRE1α) and triggered apoptosis, in avian cells (DF-1 and CEF) and in various human cancer cell types (HeLa, Cal27, HN13, A549, H1299, Huh7, and HepG2). Interestingly, the suppression of either apoptosis or UPR led to impaired NDV proliferation. Meanwhile, the inhibition of UPR by 4-PBA protected cells from NDV-induced apoptosis. Further study revealed that activation of PERK-eIF2α induced the expression of transcription factor CHOP, which subsequently promoted apoptosis by downregulating BCL-2/MCL-1, promoting JNK signaling and suppressing AKT signaling. In parallel, IRE1α mediated the splicing of XBP1 mRNA and resulted in the translation and nuclear translocation of XBP1s, thereby promoting the transcription of ER chaperones and components of ER-associated degradation (ERAD). Furthermore, IRE1α promoted apoptosis and cytokines secretion via the activation of JNK signaling. Knock down and overexpression studies showed that CHOP, IRE1α, XBP1, and JNK supported efficient virus proliferation. Our study demonstrates that the induction of eIF2α-CHOP-BCL-2/JNK and IRE1α-XBP1/JNK signaling cascades promote apoptosis and cytokines secretion, and these signaling cascades support NDV proliferation.

Evaluation of Newcastle disease virus mediated dendritic cell activation and cross-priming tumor-specific immune responses ex vivo

We have developed an oncolytic Newcastle disease virus (NDV) that has potent in vitro and in vivo anti-tumor activities and attenuated pathogenicity in chickens. In this ex vivo study using the same recombinant NDV backbone with GFP transgene (NDV-GFP, designated as rNDV), we found that rNDV induces maturation of monocyte-derived immature dendritic cells (iDCs) by both direct and indirect mechanisms, which promote development of antigen-specific T cell responses. Addition of rNDV directly to iDCs culture induced DC maturation, as demonstrated by the increased expression of costimulatory and antigen-presenting molecules as well as the production of type I interferons (IFNs). rNDV infection of the HER-2 positive human breast cancer cell line (SKBR3) resulted in apoptotic cell death, release of proinflammatory cytokines, and danger-associated molecular pattern molecules (DAMPs) including high-mobility group protein B1 (HMGB1) and heat shock protein 70 (HSP70). Addition of rNDV-infected SKBR3 cells to iDC culture resulted in greatly enhanced upregulation of the maturation markers and release of type I IFNs by DCs than rNDV-infected DCs only. When co-cultured with autologous T cells, DCs pre-treated with rNDV-infected SKBR3 cells cross-primed T cells in an antigen-specific manner. Altogether, our data strongly support the potential of oncolytic NDV as efficient therapeutic agent for cancer treatment.

Antiviral interferons induced by Newcastle disease virus (NDV) drive a tumor-selective apoptosis

Newcastle disease virus (NDV) strongly induces both type I and III antiviral interferons (IFNs-α/-β and IFN-λ, respectively) in tumor cells while it induces mainly type III IFN in normal cells. Impairment of antiviral type I IFN signaling in tumor cells is thought to be the reason for effective oncolysis. However, there is lack of clarity why lentogenic strain NDV can also induce oncolysis. NDV infection caused apoptosis in normal and tumor cells as demonstrated with the caspase-3 enzyme activation and annexin-V detection. The apoptosis response was inhibited by B18R protein (a type I IFN inhibitor) in tumor cells i.e. A549 and U87MG, and not in normal cells i.e. NB1RGB and HEK293. Similarly, UV-inactivated medium from NDV infection was shown to induce apoptosis in corresponding cells and the response was inhibited in A549 and U87MG cells with the addition of B18R protein. Treatment with combination of IFNs-α/-β/-λ or IFNs-α/-β or IFN-λ in NB1RGB, HEK293, A549 and U87MG showed that caspase activity in IFNs-α/-β/-λ group was the highest, followed with IFN-α/-β group and IFN-λ group. This suggests that tumor-selectivity of NDV is mainly because of the cumulative effect of type I and III in tumor cells that lead to higher apoptotic effect.

Virotherapy: Current Trends and Future Prospects for Treatment of Colon and Rectal Malignancies

Colorectal cancer (CRC) is one of the most common malignancies. In recent decades, early diagnosis and conventional therapies have resulted in a significant reduction in mortality. However, late stage metastatic disease still has very limited effective treatment options. There is a growing interest in using viruses to help target therapies to tumour sites. In recent years the evolution of immunotherapy has emphasised the importance of directing the immune system to eliminate tumour cells; we aim to give a state-of-the-art over-view of the diverse viruses that have been investigated as potential oncolytic agents for the treatment of CRC.

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.

Newcastle disease virus mediated apoptosis and migration inhibition of human oral cancer cells: A probable role of β-catenin and matrix metalloproteinase-7

Cancer cell metastasis and its dissemination are most enigmatic and challenging aspects in the development of its therapeutics. Newcastle disease virus (NDV) is a well-studied avian paramyxovirus frequently isolated from birds and rarely from mammals. Since the first report of its oncolytic property, many NDV strains were studied for its effect in various cancer cells. In the present study, NDV strain Bareilly was characterized for its apoptotic potential and migration inhibition in human oral cancer cells. The NDV mediated apoptosis was confirmed by flow cytometry, DNA laddering, and immunoblotting. Moreover, NDV decreased the mitochondrial membrane potential suggesting an intrinsic pathway of apoptosis in oral cancer cells. NDV infection in oral cancer cells results in migration inhibition by a reduction in levels of MMP-7. MMP-7 is one of the key target genes of β-catenin. While overexpression of MMP-7 reversed the inhibitory effect of NDV mediated migration suggested its possible involvement. Wnt/β-catenin is an essential pathway for cell growth, differentiation, and metastasis. The involvement of the Wnt/β-catenin pathway in NDV infection has never been reported. Our results showed that NDV dysregulates Wnt/β-catenin by down-regulation of p-Akt and p-GSK3β leading to degradation of β-catenin. Furthermore, NDV infection leads to a reduction in cytoplasmic and nuclear levels of β-catenin. The study will provide us with a better insight into the molecular mechanism of NDV mediated oncolysis and the key cellular partners involved in the process.

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.

Histone Deacetylase Inhibitors Enhance Cell Killing and Block Interferon-Beta Synthesis Elicited by Infection with an Oncolytic Parainfluenza Virus

Previous results have shown that infection with the cytoplasmic-replicating parainfluenza virus 5 mutant P/V-CPI- sensitizes cells to DNA damaging agents, resulting in the enhanced killing of airway cancer cells. Here, we have tested the hypothesis that histone deacetylase (HDAC) inhibitors can also act with P/V-CPI- infection to enhance cancer cell killing. Using human small cell lung cancer and laryngeal cancer cell lines, 10 HDAC inhibitors were tested for their effect on viability of P/V-CPI- infected cells. HDAC inhibitors such as scriptaid enhanced caspase-3/7, -8 and -9 activity induced by P/V-CPI- and overall cell toxicity. Scriptaid-mediated enhanced killing was eliminated in lung cancer cells that were engineered to express a protein which sequesters double stranded RNA. Scriptaid also enhanced cancer cell killing by two other negative strand RNA viruses - the La Crosse virus and vesicular stomatitis virus. Scriptaid treatment enhanced the spread of the P/V-CPI- virus through a population of cancer cells, and suppressed interferon-beta induction through blocking phosphorylation and nuclear translocation of Interferon Regulatory Factor 3 (IRF-3). Taken together, these data support a role for combinations of a cytoplasmic-replicating RNA virus such as the P/V-CPI- mutant along with chemotherapeutic agents.

Oncolytic Newcastle disease virus reduces growth of cervical cancer cell by inducing apoptosis

Although Oncolytic viruses have been regarded as a promising tool for targeted therapy of cancer, accomplishing high efficacy and specificity with this strategy is challenging. Oncolytic virotherapy is one of the novel therapeutic methods recently used for the therapy of human malignancies. Cervical cancer is on the major public health problem and the second most common cause of cancer death among females in less developed countries. The aim of this study was mainly to determine the apoptosis effect of oncolytic Newcastle disease virus (NDV) in TC-1 cell line.

In the current study, the oncolytic NDV, vaccine strain LaSota, was used to infect murine TC-1 cells of human papillomavirus (HPV)-associated carcinoma which expressing human papillomavirus 16 (HPV-16) E6/E7 antigens in vitro. The effectiveness of NDV for cervical cancer cell line was investigated by evaluating the antitumor activity of oncolytic NDV and the involved mechanisms. Antitumor activities of oncolytic NDV were assessed by cell proliferation (MTT) and lactate dehydrogenase (LDH) release analysis. In addition, molecular changes of early stage of apoptosis and the role of reactive oxygen species (ROS) were analyzed by flow cytometry and Western Blot in NDV-treated TC-1 cells.

The results showed that NDV treatment significantly decreased the viability of a TC-1 cell line and suppressed the growth by inducing apoptotic cell death. In addition, we demonstrated that NDV-induced apoptosis of TC-1 cells is mediated by ROS production. In summary, our findings suggest that oncolytic NDV is a possible therapeutic candidate as a selective antitumor agent for the treatment of cervical cancer.

Newcastle disease virus selectively infects dividing cells and promotes viral proliferation

Newcastle disease virus (NDV) can select cells to infect, but the mechanism of its cell selectivity has not been comprehensively investigated. Here, we use HeLa cells to establish that NDV can selectively infect cells at the single-cell level. We labeled proliferating cells with 5′-bromo-2-deoxyuridine (BrdU) and examined the colocalization of BrdU with NDV in cells to clarify the relationships between NDV infection and cell proliferation. Receptors at the plasma membrane mediate NDV entry into host cells. We labeled sialic acid receptor isoforms, compared their densities between different cell types and measured the sialic acid receptor densities in different cell phases. Our results suggest that NDV displays host tropism to HeLa cells compared to BHK cells and that the differences in the receptor isoform expression patterns between cell types contribute to the selection of HeLa by NDV. At the single-cell level, the dynamics of receptor expression changes during different cell phases contributing to the selection of cells in S/G2 phase for NDV infection. Furthermore, cell proliferation benefits viral replication, and enhanced virus replication leads to increased damage to cells. The elucidation of the mechanisms underlying host cell selection by NDV may help in the screening and characterizing of additional candidate oncolytic virus strains.

Regression of solid breast tumours in mice by Newcastle disease virus is associated with production of apoptosis related-cytokines

BACKGROUND

Different strains of Newcastle disease virus (NDV) worldwide proved to have tumouricidal activity in several types of cancer cells. However, the possible anti-cancer activity of Malaysian NDV AF2240 strain and its mechanism of action remains unknown. The ability of cytokine-related apoptosis-inducing NDV AF2240 to treat breast cancer was investigated in the current study.

METHODS

A total of 90 mice were used and divided into 15 groups, each group comprising of 6 mice. Tumour, body weight and mortality of the mice were determined throughout the experiment, to observe the effect of NDV and NDV + tamoxifen treatments on the mice. In addition, the toxic effect of the treatments was determined through liver function test. In order to elucidate the involvement of cytokine production induced by NDV, a total of six cytokines, i.e. IL-6, IFN-γ, MCP-1, IL-10, IL12p70 and TNF-α were measured using cytometric bead array assay (plasma) and enzyme-linked immunosorbent spot (isolated splenocytes).

RESULTS

The results demonstrated that 4 T1 breast cancer cells in allotransplanted mice treated with AF2240 showed a noticeable inhibition of tumour growth and induce apoptotic-related cytokines.

CONCLUSIONS

NDV AF2240 suppression of breast tumour growth is associated with induction of apoptotic-related cytokines. It would be important to further investigate the molecular mechanism underlaying cytokines production by Newcastle disease virus.

Fludarabine as an Adjuvant Improves Newcastle Disease Virus-Mediated Antitumor Immunity in Hepatocellular Carcinoma

In addition to direct oncolysis, oncolytic viruses (OVs) also induce antitumor immunity, also called viro-immunotherapy. Limited viral replication and immune-negative feedback are the major hurdles to effective viro-immunotherapy. In this study, we found that use of an adjuvant of fludarabine, a chemotherapeutic drug for chronic myeloid leukemia, increased the replication of Newcastle disease virus (NDV) by targeting signal transducer and activator of transcription 1 (STAT1), which led to enhanced oncolysis of hepatocellular carcinoma (HCC) cells. Moreover, fludarabine accelerated ubiquitin-proteasomal degradation by enhancing ubiquitylation rather than proteasomal activity. This resulted in accelerated degradation of phosphorylated STAT3 and indoleamine 2, 3-dioxygenase 1 (IDO1), whose expression was induced by NDV infection. In addition, fludarabine significantly increased the NDV-induced infiltration of NK cells and decreased the number of NDV-induced myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. The aforementioned effects of fludarabine significantly improved NDV-mediated antitumor immunity and prolonged survival in mouse model of HCC. Our findings indicate the utility of fludarabine as an adjuvant for oncolytic anticancer viro-immunotherapy.

PTEN inhibits non-small cell lung cancer cell growth by promoting G0/G1 arrest and cell apoptosis

Non-small cell lung cancer (NSCLC) is a major type of human lung cancer and the primary cause of cancer-associated cases of mortality worldwide. Phosphatase and tensin homolog (PTEN) is a potent tumor suppressor gene in various human cancer types. The aim of the current study was to explore the role of PTEN and its associated regulatory mechanisms in NSCLC. Firstly, the expression of PTEN was detected using western blotting in a variety of NSCLC cell lines. The results revealed that compared with normal control cells, PTEN levels were significantly decreased in NSCLC cell lines (P<0.01). Short hairpin (sh)RNAs specific to PTEN were also used to knockdown endogenous PTEN in NSCLC cells. The results indicated that cell viability was significantly increased in PTEN-knockdown cells compared with those transfected with negative control shRNA (P<0.01). Conversely, overexpression of PTEN in A549 and SK-MES-1 cells significantly decreased the optical density of NSCLC cells (P<0.01). Flow cytometry was used to investigate the cell cycle; the results revealed that PTEN knockdown significantly increased the percentage of cells at G₀/G₁ phase (P<0.01) and decreased the number of cells at S phase (P<0.01). The molecular mechanism was further explored using western blotting and the results demonstrated that PTEN overexpression increased the levels of cleaved caspase-3 (P<0.01). These results suggest that PTEN may be a potential target gene for gene therapy in patients with NSCLCs.

Newcastle disease virus V protein inhibits apoptosis in DF-1 cells by downregulating TXNL1

Many viral proteins are related to suppressing apoptosis in target cells and are hence beneficial to viral replication. The V protein of Newcastle disease virus (NDV) is one such protein that plays an important role in inhibiting apoptosis in a species-specific manner. However, to date, there have been no reports clarifying the antiapoptotic mechanisms of the V protein. The present study was undertaken to determine the apoptotic potential of the V protein in a chicken embryo fibroblast cell line (DF-1 cell) and to elucidate its molecular mechanisms of action. Here, a yeast two-hybrid system was used to screen the host proteins that interact with the V protein and identified thioredoxin-like protein 1 (TXNL1) as a potential binding partner. Immuno-colocalization of V protein and TXNL1 protein in DF-1 cells further verified the interaction of the two proteins. Through the overexpression of TXNL1 protein and knockdown of TXNL1 protein in DF-1 cells, the effects of NDV replication and cell apoptosis were examined. Cell apoptosis was detected by flow cytometry. The mRNA and protein expression levels of Bax, Bcl-2 and Caspase-3 were detected by quantitative real-time PCR (Q-PCR) and Western blotting. NDV expression was detected by Q-PCR and plaque assay. The results revealed that the TXNL1 protein induced apoptosis and inhibited NDV replication in DF-1 cells. Furthermore, the Western blot and Q-PCR results suggested that TXNL1 induced cell apoptosis through a pathway involving Bcl-2\Bax and Caspase-3. Finally, this work provides insight into the mechanism by which the V protein inhibits apoptosis.

Newcastle Disease Virus V Protein Inhibits Cell Apoptosis and Promotes Viral Replication by Targeting CacyBP/SIP

Newcastle disease virus (NDV) has been classified by the World Organization for Animal Health (OIE) as a notable disease-causing virus, and this virus has the ability to infect a wide range of birds. V protein is a non-structural protein of NDV. V protein has been reported to inhibit cell apoptosis (Park et al., 2003a) and promote viral replication (Huang et al., 2003), however, the mechanisms of action of V protein have not been elucidated. In the present study, a yeast two-hybrid screen was performed, and V protein was found to interact with the CacyBP/SIP protein. The results of co-immunoprecipitation and immuno-colocalization assays confirmed the interaction between V protein and CacyBP/SIP. The results of quantitative-PCR and viral plaque assays showed that overexpression of CacyBP/SIP inhibited viral replication in DF-1 cells. Overexpression of CacyBP/SIP in DF-1 cells induced caspase3-dependent apoptosis. The effect of knocking down CacyBP/SIP by siRNA was the opposite of that observed upon overexpression. Moreover, it is known that NDV induces cell apoptosis via multiple caspase-dependent pathways. Furthermore, V protein inhibited cell apoptosis and downregulated CacyBP/SIP expression in DF-1 cells. Taken together, the findings of the current study indicate that V protein interacts with CacyBP/SIP, thereby regulating cell apoptosis and viral replication.