Zika virus NS5 protein inhibits cell growth and invasion of glioma

An Overview of Zika Virus and Zika Virus Induced Neuropathies

Flaviviruses pose a major public health concern across the globe. Among them, Zika virus (ZIKV) is an emerging and reemerging arthropod-borne flavivirus that has become a major international public health problem following multiple large outbreaks over the past two decades. The majority of infections caused by ZIKV exhibit mild symptoms. However, the virus has been found to be associated with a variety of congenital neural abnormalities, including microcephaly in children and Guillain-Barre syndrome in adults. The exact prediction of the potential of ZIKV transmission is still enigmatic and underlines the significance of routine detection of the virus in suspected areas. ZIKV transmission from mother to fetus (including fetal abnormalities), viral presence in immune-privileged areas, and sexual transmission demonstrate the challenges in understanding the factors governing viral persistence and pathogenesis. This review illustrates the transmission patterns, epidemiology, control strategies (through vaccines, antivirals, and vectors), oncolytic aspects, molecular insights into neuro-immunopathogenesis, and other neuropathies caused by ZIKV. Additionally, we summarize in vivo and in vitro models that could provide an important platform to study ZIKV pathogenesis and the underlying governing cellular and molecular mechanisms.

Zika virus and brain cancer: Can Zika be an effective treatment for brain cancer? A systematic review

INTRODUCTION

Many studies have highlighted the use of oncolytic viruses as a new class of therapeutic agents for central nervous system (CNS) tumors, especially glioblastomas (GMB). Zika Virus (ZIKV) proteins targeted to specific stem cells have been studied in vitro and animal models with promising results.

MATERIALS AND METHODS

A systematic review was evaluated the efficacy and safety of the ZIKV use for CNS tumors treatment. Data were extracted and the in vivo studies were evaluated using the Robins-I tool. We assessed bias in each study using criteria such as selection bias, performance bias, detection bias, attrition bias, reporting bias, and others. According to Cochrane guidelines, bias was classified as high, low, or uncertain. High bias occurred when studies did not meet the criteria. Low bias was assigned when criteria were clearly met. Uncertain bias reflected insufficient information for a clear classification.

RESULTS

The 14 included studies shown that ZIKV reduced cell viability or inhibited the growth, proliferation of glioma stem cells (GSCs), and Bcl2 expression - which could potentially enhance the effect of chemotherapy/radiotherapy; caused cytopathic effects, induced tumor cell damage, manifested oncolytic properties, and even selectively safely killed GSCs; ultimately, it led to significant tumor remission and enhanced long-term survival through enhanced T-cell response.

CONCLUSIONS

Although current evidence suggests ZIKV as a promising treatment for CNS tumors and may improve survival when combined with surgery and radiotherapy. Despite limited human evidence, it shows potential benefits. Further research is needed to confirm safety, efficacy, and optimize treatment in humans.

Optimization of SOX2 Expression for Enhanced Glioblastoma Stem Cell Virotherapy

The Zika virus has been shown to infect glioblastoma stem cells via the membrane receptorα v β 5 , which is activated by the stem-specific transcription factor SOX2. Since the expression level of SOX2 is an important predictive marker for successful virotherapy, it is important to understand the fundamental mechanisms of the role of SOX2 in the dynamics of cancer stem cells and Zika viruses. In this paper, we develop a mathematical ODE model to investigate the effects of SOX2 expression levels on Zika virotherapy against glioblastoma stem cells. Our study aimed to identify the conditions under which SOX2 expression level, viral infection, and replication can reduce or eradicate the glioblastoma stem cells. Analytic work on the existence and stability conditions of equilibrium points with respect to the basic reproduction number are provided. Numerical results were in good agreement with analytic solutions. Our results show that critical threshold levels of both SOX2 and viral replication, which change the stability of equilibrium points through population dynamics such as transcritical and Hopf bifurcations, were observed. These critical thresholds provide the optimal conditions for SOX2 expression levels and viral bursting sizes to enhance therapeutic efficacy of Zika virotherapy against glioblastoma stem cells. This study provides critical insights into optimizing Zika virus-based treatment for glioblastoma by highlighting the essential role of SOX2 in viral infection and replication.

The Oncolytic Activity of Zika Viral Therapy in Human Neuroblastoma In Vivo Models Confers a Major Survival Advantage in a CD24-dependent Manner

Neuroblastoma is the most common extracranial tumor, accounting for 15% of all childhood cancer-related deaths. The long-term survival of patients with high-risk tumors is less than 40%, and MYCN amplification is one of the most common indicators of poor outcomes. Zika virus (ZIKV) is a mosquito-borne flavivirus associated with mild constitutional symptoms outside the fetal period. Our published data showed that high-risk and recurrent neuroblastoma cells are permissive to ZIKV infection, resulting in cell type-specific lysis. In this study, we assessed the efficacy of ZIKV as an oncolytic treatment for high-risk neuroblastoma using in vivo tumor models. Utilizing both MYCN-amplified and non-amplified models, we demonstrated that the application of ZIKV had a rapid tumoricidal effect. This led to a nearly total loss of the tumor mass without evidence of recurrence, offering a robust survival advantage to the host. Detection of the viral NS1 protein within the tumors confirmed that a permissive infection preceded tissue necrosis. Despite robust titers within the tumor, viral shedding to the host was poor and diminished rapidly, correlating with no detectable side effects to the murine host. Assessments from both primary pretreatment and recurrent posttreatment isolates confirmed that permissive sensitivity to ZIKV killing was dependent on the expression of CD24, which was highly expressed in neuroblastomas and conferred a proliferative advantage to tumor growth. Exploiting this viral sensitivity to CD24 offers the possibility of its use as a prognostic target for a broad population of expressing cancers, many of which have shown resistance to current clinical therapies.

SIGNIFICANCE

Sensitivity to the tumoricidal effect of ZIKV on high-risk neuroblastoma tumors is dependent on CD24 expression, offering a prognostic marker for this oncolytic therapy in an extensive array of CD24-expressing cancers.

Breaking Barriers: A Future Perspective on Glioblastoma Therapy with mRNA-Based Immunotherapies and Oncolytic Viruses

The use of mRNA-based immunotherapies that leverage the genomes of oncolytic viruses holds significant promise in addressing glioblastoma (GBM), an exceptionally aggressive neurological tumor. We explore the significance of mRNA-based platforms in the area of immunotherapy, introducing an innovative approach to mitigate the risks associated with the use of live viruses in cancer treatment. The ability to customize oncolytic virus genome sequences enables researchers to precisely target specific cancer cells, either through viral genome segments containing structural proteins or through a combination of regions with oncolytic potential. This strategy may enhance treatment effectiveness while minimizing unintended impacts on non-cancerous cells. A notable case highlighted here pertains to advanced findings regarding the application of the Zika virus (ZIKV) in GBM treatment. ZIKV, a member of the family Flaviviridae, shows oncolytic properties against GBM, opening novel therapeutic avenues. We explore intensive investigations of glioblastoma stem cells, recognized as key drivers in GBM initiation, progression, and resistance to therapy. However, a comprehensive elucidation of ZIKV's underlying mechanisms is imperative to pave the way for ZIKV-based clinical trials targeting GBM patients. This investigation into harnessing the potential of oncolytic-virus genomes for mRNA-based immunotherapies underscores its noteworthy implications, potentially paving the way for a paradigm shift in cancer treatment strategies.

Flaviviruses in AntiTumor Therapy

Oncolytic viruses offer a promising approach to tumor treatment. These viruses not only have a direct lytic effect on tumor cells but can also modify the tumor microenvironment and activate antitumor immunity. Due to their high pathogenicity, flaviviruses have often been overlooked as potential antitumor agents. However, with recent advancements in genetic engineering techniques, an extensive history with vaccine strains, and the development of new attenuated vaccine strains, there has been a renewed interest in the Flavivirus genus. Flaviviruses can be genetically modified to express transgenes at acceptable levels, and the stability of such constructs has been greatly improving over the years. The key advantages of flaviviruses include their reproduction cycle occurring entirely within the cytoplasm (avoiding genome integration) and their ability to cross the blood-brain barrier, facilitating the systemic delivery of oncolytics against brain tumors. So far, the direct lytic effects and immunomodulatory activities of many flaviviruses have been widely studied in experimental animal models across various types of tumors. In this review, we delve into the findings of these studies and contemplate the promising potential of flaviviruses in oncolytic therapies.

Intrinsic features of Zika Virus non-structural proteins NS2A and NS4A in the regulation of viral replication

Zika virus (ZIKV) is a mosquito-borne flavivirus and can cause neurodevelopmental disorders in fetus. As a neurotropic virus, ZIKV persistently infects neural tissues during pregnancy but the viral pathogenesis remains largely unknown. ZIKV has a positive-sense and single-stranded RNA genome, which encodes 7 non-structural (NS) proteins, participating in viral replication and dysregulation of host immunity. Like those in many other viruses, NS proteins are considered to be products evolutionarily beneficiary to viruses and some are virulence factors. However, we found that some NS proteins encoded by ZIKV genome appeared to function against the viral replication. In this report we showed that exogenously expressed ZIKV NS2A and NS4A inhibited ZIKV infection by inhibiting viral RNA replication in microglial cells and astrocytes. To understand how viral NS proteins suppressed viral replication, we analyzed the transcriptome of the microglial cells and astrocytes and found that expression of NS4A induced the upregulation of ISGs, including MX1/2, OAS1/2/3, IFITM1, IFIT1, IFI6, IFI27, ISG15 or BST2 through activating the ISGF3 signaling pathway. Upregulation of these ISGs seemed to be related to the inhibition of ZIKV replication, since the anti-ZIKV function of NS4A was partially attenuated when the cells were treated with Abrocitinib, an inhibitor of the ISGF3 signaling pathway, or were knocked down with STAT2. Aborting the protein expression of NS4A, but not its nucleic acid, eliminated the antiviral activity of NS4A effectively. Dynamic expression of viral NS proteins was examined in ZIKV-infected microglial cells and astrocytes, which showed comparatively NS4A occurred later than other NS proteins during the infection. We hypothesize that NS4A may possess intrinsic features to serve as a unique type of pathogen associated molecular pattern (PAMP), detectable by the cells to induce an innate immune response, or function with other mechanisms, to restrict the viral replication to a certain level as a negative feedback, which may help ZIKV maintain its persistent infection in fetal neural tissues.

The birth of microcephaly infants due to ZIKV infection in pregnant women is related to ZIKV persistent infection. However, it is unclear how ZIKV maintains its persistent infection. In this work, we observed the delayed appearance of ZIKV NS4A protein in neuroglia including microglia and astrocytes compared with other non-structural proteins. Subsequently, we revealed that ZIKV NS4A inhibited viral RNA replication by activating the ISGF3 signaling pathway and inducing the production of ISGs. Aborting NS4A protein expression totally rescued ZIKV viral replication. Our study, combined with the previous findings, suggests that viral non-structural proteins may regulate viral replication, thus perpetuating ZIKV infection. Our hypothesis provides a mechanism for ZIKV to maintain its status of a persistent infection during viral infection in fetus, which can shed lights on our further understanding of viral neuropathogenesis in ZIKV infection.

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.

MEK Inhibitor Augments Antitumor Activity of B7-H3-Redirected Bispecific Antibody

Targeting cancer antigens by T cell-engaging bispecific antibody (BiAb) or chimeric antigen receptor T cell therapy has achieved successes in hematological cancers, but attempts to use it to fight solid cancers have been disappointing, in part due to antigen escape. MEK inhibitor had limited activity as a single agent, but enhanced antitumor activity when combined with other therapies, such as targeted drugs or immunotherapy agents. This study aimed to analyze the expression of B7-H3 in non-small-cell lung cancer (NSCLC) and bladder cancer (BC) and to evaluate the combinatorial antitumor effect of B7-H3 × CD3 BiAb with MEK inhibitor trametinib. We found B7-H3 was highly expressed in NSCLC and BC compared with normal samples and its increased expression was associated with poor prognosis. Treatment with trametinib alone could induce apoptosis in tumor cell, while has no effect on T cell proliferation, and a noticeable elevation of B7-H3 expression in tumor cells was also observed following treatment. B7-H3 × CD3 BiAb specifically and efficiently redirected their cytotoxicity against B7-H3 overexpressing tumor cells both in vitro and in xenograft mouse models. While trametinib treatment alone affected tumor growth, the combined therapy increased T cell infiltration and significantly suppressed tumor growth. Together, these data suggest that combination therapy with B7-H3 × CD3 BiAb and MEK inhibitor may serve as a new therapeutic strategy in the future clinical practice for the treatment of NSCLC and BC.