A Tumor-Targeted Replicating Oncolytic Adenovirus Ad-TD-nsIL12 as a Promising Therapeutic Agent for Human Esophageal Squamous Cell Carcinoma

A viral attack on brain tumors: the potential of oncolytic virus therapy

Managing malignant brain tumors remains a significant therapeutic hurdle that necessitates further research to comprehend their treatment potential fully. Oncolytic viruses (OVs) offer many opportunities for predicting and combating tumors through several mechanisms, with both preclinical and clinical studies demonstrating potential. OV therapy has emerged as a potent and effective method with a dual mechanism. Developing innovative and effective strategies for virus transduction, coupled with immune checkpoint inhibitors or chemotherapy drugs, strengthens this new technique. Furthermore, the discovery and creation of new OVs that can seamlessly integrate gene therapy strategies, such as cytotoxic, anti-angiogenic, and immunostimulatory, are promising advancements. This review presents an overview of the latest advancements in OVs transduction for brain cancer, focusing on the safety and effectiveness of G207, G47Δ, M032, rQNestin34.5v.2, C134, DNX-2401, Ad-TD-nsIL12, NSC-CRAd-S-p7, TG6002, and PVSRIPO. These are evaluated in both preclinical and clinical models of various brain tumors.

Tutorial: design, production and testing of oncolytic viruses for cancer immunotherapy

Oncolytic viruses (OVs) represent a novel class of cancer immunotherapy agents that preferentially infect and kill cancer cells and promote protective antitumor immunity. Furthermore, OVs can be used in combination with established or upcoming immunotherapeutic agents, especially immune checkpoint inhibitors, to efficiently target a wide range of malignancies. The development of OV-based therapy involves three major steps before clinical evaluation: design, production and preclinical testing. OVs can be designed as natural or engineered strains and subsequently selected for their ability to kill a broad spectrum of cancer cells rather than normal, healthy cells. OV selection is further influenced by multiple factors, such as the availability of a specific viral platform, cancer cell permissivity, the need for genetic engineering to render the virus non-pathogenic and/or more effective and logistical considerations around the use of OVs within the laboratory or clinical setting. Selected OVs are then produced and tested for their anticancer potential by using syngeneic, xenograft or humanized preclinical models wherein immunocompromised and immunocompetent setups are used to elucidate their direct oncolytic ability as well as indirect immunotherapeutic potential in vivo. Finally, OVs demonstrating the desired anticancer potential progress toward translation in patients with cancer. This tutorial provides guidelines for the design, production and preclinical testing of OVs, emphasizing considerations specific to OV technology that determine their clinical utility as cancer immunotherapy agents.

OV Modulators of the Paediatric Brain TIME: Current Status, Combination Strategies, Limitations and Future Directions

Oncolytic viruses (OVs) are characterised by their preference for infecting and replicating in tumour cells either naturally or after genetic modification, resulting in oncolysis. Furthermore, OVs can elicit both local and systemic anticancer immune responses while specifically infecting and lysing tumour cells. These characteristics render them a promising therapeutic approach for paediatric brain tumours (PBTs). PBTs are frequently marked by a cold tumour immune microenvironment (TIME), which suppresses immunotherapies. Recent preclinical and clinical studies have demonstrated the capability of OVs to induce a proinflammatory immune response, thereby modifying the TIME. In-depth insights into the effect of OVs on different cell types in the TIME may therefore provide a compelling basis for using OVs in combination with other immunotherapy modalities. However, certain limitations persist in our understanding of oncolytic viruses' ability to regulate the TIME to enhance anti-tumour activity. These limitations primarily stem from the translational limitations of model systems, the difficulties associated with tracking reliable markers of efficacy throughout the course of treatment and the role of pre-existing viral immunity. In this review, we describe the different alterations observed in the TIME in PBTs due to OV treatment, combination therapies of OVs with different immunotherapies and the hurdles limiting the development of effective OV therapies while suggesting future directions based on existing evidence.

Zika Virus: A Neurotropic Warrior against High-Grade Gliomas-Unveiling Its Potential for Oncolytic Virotherapy

Gliomas account for approximately 75-80% of all malignant primary tumors in the central nervous system (CNS), with glioblastoma multiforme (GBM) considered the deadliest. Despite aggressive treatment involving a combination of chemotherapy, radiotherapy, and surgical intervention, patients with GBM have limited survival rates of 2 to 5 years, accompanied by a significant decline in their quality of life. In recent years, novel management strategies have emerged, such as immunotherapy, which includes the development of vaccines or T cells with chimeric antigen receptors, and oncolytic virotherapy (OVT), wherein wild type (WT) or genetically modified viruses are utilized to selectively lyse tumor cells. In vitro and in vivo studies have shown that the Zika virus (ZIKV) can infect glioma cells and induce a robust oncolytic activity. Consequently, interest in exploring this virus as a potential oncolytic virus (OV) for high-grade gliomas has surged. Given that ZIKV actively circulates in Colombia, evaluating its neurotropic and oncolytic capabilities holds considerable national and international importance, as it may emerge as an alternative for treating highly complex gliomas. Therefore, this literature review outlines the generalities of GBM, the factors determining ZIKV's specific tropism for nervous tissue, and its oncolytic capacity. Additionally, we briefly present the progress in preclinical studies supporting the use of ZIKV as an OVT for gliomas.

Evolving Horizons: Adenovirus Vectors' Timeless Influence on Cancer, Gene Therapy and Vaccines

Efficient and targeted delivery of a DNA payload is vital for developing safe gene therapy. Owing to the recent success of commercial oncolytic vector and multiple COVID-19 vaccines, adenovirus vectors are back in the spotlight. Adenovirus vectors can be used in gene therapy by altering the wild-type virus and making it replication-defective; specific viral genes can be removed and replaced with a segment that holds a therapeutic gene, and this vector can be used as delivery vehicle for tissue specific gene delivery. Modified conditionally replicative-oncolytic adenoviruses target tumors exclusively and have been studied in clinical trials extensively. This comprehensive review seeks to offer a summary of adenovirus vectors, exploring their characteristics, genetic enhancements, and diverse applications in clinical and preclinical settings. A significant emphasis is placed on their crucial role in advancing cancer therapy and the latest breakthroughs in vaccine clinical trials for various diseases. Additionally, we tackle current challenges and future avenues for optimizing adenovirus vectors, promising to open new frontiers in the fields of cell and gene therapies.

Virus-Protein Corona Replacement Strategy to Improve the Antitumor Efficacy of Intravenously Injected Oncolytic Adenovirus

Intravenous administration of oncolytic adenoviruses (OVs) is a hopeful tumor therapeutic modality. However, the sharp clearance of OVs by the immune system dampens its effectiveness. Many studies have attempted to extend the circulation of intravenously administered OVs, almost all by preventing OVs from binding to neutralizing antibodies and complements in the blood, but the results have not been satisfactory. In contrast to previous conclusions, we found that the key to improving the circulation of OVs is to prevent the formation of the virus-protein corona rather than simply preventing the binding of neutralizing antibodies or complements to OVs. After identifying the key protein components of the virus-protein corona, we proposed a virus-protein corona replacement strategy, where an artificial virus-protein corona was formed on OVs to completely prevent the interaction of OVs with key virus-protein corona components in the plasma. It was found that this strategy dramatically prolonged the circulation time of OVs by over 30 fold and increased the distribution of OVs in tumors by over 10-fold, resulting in superior antitumor efficacy in primary and metastatic tumor models. Our finding provides a perspective on intravenous delivery of OVs, shifting the focus of future studies from preventing OV binding with neutralization antibodies and complements to preventing OVs from interacting with key virus-protein corona components in the plasma.

Oncolytic virotherapies for pediatric tumors

INTRODUCTION

Many pediatric patients with malignant tumors continue to suffer poor outcomes. The current standard of care includes maximum safe surgical resection followed by chemotherapy and radiation which may be associated with considerable long-term morbidity. The emergence of oncolytic virotherapy (OVT) may provide an alternative or adjuvant treatment for pediatric oncology patients.

AREAS COVERED

We reviewed seven virus types that have been investigated in past or ongoing pediatric tumor clinical trials: adenovirus (AdV-tk, Celyvir, DNX-2401, VCN-01, Ad-TD-nsIL-12), herpes simplex virus (G207, HSV-1716), vaccinia (JX-594), reovirus (pelareorep), poliovirus (PVSRIPO), measles virus (MV-NIS), and Senecavirus A (SVV-001). For each virus, we discuss the mechanism of tumor-specific replication and cytotoxicity as well as key findings of preclinical and clinical studies.

EXPERT OPINION

Substantial progress has been made in the past 10 years regarding the clinical use of OVT. From our review, OVT has favorable safety profiles compared to chemotherapy and radiation treatment. However, the antitumor effects of OVT remain variable depending on tumor type and viral agent used. Although the widespread adoption of OVT faces many challenges, we are optimistic that OVT will play an important role alongside standard chemotherapy and radiotherapy for the treatment of malignant pediatric solid tumors in the future.

Syrian hamster as an ideal animal model for evaluation of cancer immunotherapy

Cancer immunotherapy (CIT) has emerged as an exciting new pillar of cancer treatment. Although benefits have been achieved in individual patients, the overall response rate is still not satisfactory. To address this, an ideal preclinical animal model for evaluating CIT is urgently needed. Syrian hamsters present similar features to humans with regard to their anatomy, physiology, and pathology. Notably, the histological features and pathological progression of tumors and the complexity of the tumor microenvironment are equivalent to the human scenario. This article reviews the current tumor models in Syrian hamster and the latest progress in their application to development of tumor treatments including immune checkpoint inhibitors, cytokines, adoptive cell therapy, cancer vaccines, and oncolytic viruses. This progress strongly advocates Syrian hamster as an ideal animal model for development and assessment of CIT for human cancer treatments. Additionally, the challenges of the Syrian hamster as an animal model for CIT are also discussed.

A comparative study of the ability of recombinant oncolytic adenovirus, doxorubicin and tamoxifen to inhibit the proliferation of breast cancer cells

In this study, we compared the inhibitory effects of recombinant oncolytic adenovirus (Ad‐apoptin‐hTERTp‐E1a, Ad‐VT) with that of doxorubicin (DOX), a first‐line chemotherapy drug, and tamoxifen (TAM), an endocrine therapy drug, on the proliferation of breast cancer cells. We found that Ad‐VT could effectively inhibit the proliferation of breast cancer cells (p < 0.01); the inhibition rate of Ad‐VT on normal mammary epithelial MCF‐10A cells was less than 20%. DOX can effectively inhibit the proliferation of breast cancer cells and also has a strong inhibitory effect on MCF‐10A cells (p < 0.01). TAM also has a strong inhibitory effect on breast cancer cells, among which the oestrogen‐dependent MCF‐7 cell inhibition was stronger (p < 0.01), At higher concentrations, TAM also had a high rate of inhibition (>70%) on the proliferation of MCF‐10A cells. We also found that both recombinant adenovirus and both drugs could successfully induce tumour cell apoptosis. Further Western blot results showed that the recombinant adenovirus killed breast cancer cells through the endogenous apoptotic pathway. Analysis of the nude mouse subcutaneous breast cancer model showed that Ad‐VT significantly inhibited tumour growth (the luminescence rate of cancer cells was reduced by more than 90%) and improved the survival rate of tumour‐bearing mice (p < 0.01). Compared with DOX and TAM, Ad‐VT has a significant inhibitory effect on breast cancer cells, but almost no inhibitory effect on normal breast epithelial cells, and this inhibitory effect is mainly through the endogenous apoptotic pathway. These results indicate that Ad‐VT has significant potential as a drug for the treatment of breast cancer.

An effective therapeutic regime for treatment of glioma using oncolytic vaccinia virus expressing IL-21 in combination with immune checkpoint inhibition

Glioblastoma (GBM) is the most common primary malignant tumor in the brain, accounting for 51.4% of all primary brain tumors. GBM has a highly immunosuppressive tumor microenvironment (TME) and, as such, responses to immunotherapeutic strategies are poor. Vaccinia virus (VV) is an oncolytic virus that has shown tremendous therapeutic effect in various tumor types. In addition to its directly lytic effect on tumor cells, it has an ability to enhance immune cell infiltration into the TME allowing for improved immune control over the tumor. Here, we used a new generation of VV expressing the therapeutic payload interleukin-21 to treat murine GL261 glioma models. After both intratumoral and intravenous delivery, virus treatment induced remodeling of the TME to promote a robust anti-tumor immune response that resulted in control over tumor growth and long-term survival in both subcutaneous and orthotopic mouse models. Treatment efficacy was significantly improved in combination with systemic α-PD1 therapy, which is ineffective as a standalone treatment but synergizes with oncolytic VV to enhance therapeutic outcomes. Importantly, this study also revealed the upregulation of stem cell memory T cell populations after the virus treatment that exert strong and durable anti-tumor activity.

Redirecting anti-Vaccinia virus T cell immunity for cancer treatment by AAV-mediated delivery of the VV B8R gene

Immunotherapies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor-T (CAR-T) cells, are only efficient in a small proportion of tumor patients. One of the major reasons for this is the lack of immune cell infiltration and activation in the tumor microenvironment (TME). Recent research reported that abundant bystander CD8+ T cells targeting viral antigens exist in tumor infiltrates and that virus-specific memory T cells could be recalled to kill tumor cells. Therefore, virus-specific memory T cells may be effective candidates for tumor immunotherapy. In this study, we established subcutaneous tumor mice models that were pre-immunized with Vaccinia virus (VV) and confirmed that tumor cells with ectopic expression of the viral B8R protein could be recognized and killed by memory T cells. To create a therapeutic delivery system, we designed a recombinant adeno-associated virus (rAAV) with a modified tumor-specific promoter and used it to deliver VV B8R to tumor cells. We observed that rAAV gene therapy can retard tumor growth in VV pre-immunized mice. In summary, our study demonstrates that rAAV containing a tumor-specific promoter to restrict VV B8R gene expression to tumor cells is a potential therapeutic agent for cancer treatment in VV pre-immunized or VV-treated mice bearing tumors.

Roles of the Exosomes Derived From Myeloid-Derived Suppressor Cells in Tumor Immunity and Cancer Progression

Tumor immunity is involved in malignant tumor progression. Myeloid-derived suppressor cells (MDSCs) play an irreplaceable role in tumor immunity. MDSCs are composed of immature myeloid cells and exhibit obvious immunomodulatory functions. Exosomes released by MDSCs (MDSCs-Exos) have similar effects to parental MDSCs in regulating tumor immunity. In this review, we provided a comprehensive description of the characteristics, functions and mechanisms of exosomes. We analyzed the immunosuppressive, angiogenesis and metastatic effects of MDSCs-Exos in different tumors through multiple perspectives. Immunotherapy targeting MDSCs-Exos has demonstrated great potential in cancers and non-cancerous diseases.

Total flavonoids of Taraxacum mongolicum inhibit non-small cell lung cancer by regulating immune function

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum mongolicum Hand.-Mazz. has been used in lung cancer treatment in Chinese medicine. However, its specific mechanism of action has not yet been reported, and developing pharmaceutical anti-cancer resources is important. Here, we aimed to elucidate the anti-tumor effects of dandelion in vitro and in vivo and assess its effects on immune function in lung cancer patients.

AIM OF THE STUDY

In the present study, we mainly observed the therapeutic effects of total flavonoids from Taraxacum mongolicum Hand.-Mazz. (TFTM) on non-small cell lung cancer and its influence on the body's immune function.

MATERIALS AND METHODS

In vitro experiments on A549 and H1299 cells were performed using the CCK8 method; the proliferation and migration of cells were observed to investigate the wound healing effects of TFTM, and flow cytometry was used to detect the apoptotic rate of TFTM on lung cancer cells. In vivo experiments were preformed to establish a non-small cell lung cancer mouse model using subcutaneously transplanted Lewis cells, and the body weight and tumor growth of the mice were recorded. Hematoxylin and eosin staining was performed for tumor tissue to assess pathological changes. The thymus, spleen, and lungs were isolated for to calculate organ index. The CD4+, CD8+, and CD4+/CD8+ levels were detected in mouse spleen using flow cytometry, and IL-2, IL-3, IFN-γ, and TNF-α levels were determined in serum using enzyme-linked immunosorbent assay. Expressions of IL-2, IL-3, IFN-γ, and TNF-α were detected using quantitative real-time PCR in tumor tissues, and Ki67 expression was observed by immunofluorescence.

RESULTS

At 24 h, TFTM (100 and 200 μg/mL) had the best inhibitory effect on the proliferation of A549 and H1299 cells. The cell migration rate significantly reduced (P < 0.01), and the tumor inhibition rate increased (P < 0.01) and promoted apoptosis (P < 0.01). The mouse thymus index significantly increased (P < 0.05) and mouse spleen index reduced (P < 0.05). The CD4+, CD8+, and CD4+/CD8+ levels in Lewis lung cancer mouse model increased, as did the levels of IL-2, IL-3, IFN-γ, and TNF-α in the serum and tumor of mice; Ki67 expression in tumor tissues significantly reduced (P < 0.01).

CONCLUSION

TFTM has an inhibitory effect on lung cancer. The mechanism may be that it improves the host's protective immune response by having a milder tumor growth inhibitory effect than cyclophosphamide.

Models for Translational Proton Radiobiology-From Bench to Bedside and Back

The number of proton therapy centers worldwide are increasing steadily, with more than two million cancer patients treated so far. Despite this development, pending questions on proton radiobiology still call for basic and translational preclinical research. Open issues are the on-going discussion on an energy-dependent varying proton RBE (relative biological effectiveness), a better characterization of normal tissue side effects and combination treatments with drugs originally developed for photon therapy. At the same time, novel possibilities arise, such as radioimmunotherapy, and new proton therapy schemata, such as FLASH irradiation and proton mini-beams. The study of those aspects demands for radiobiological models at different stages along the translational chain, allowing the investigation of mechanisms from the molecular level to whole organisms. Focusing on the challenges and specifics of proton research, this review summarizes the different available models, ranging from in vitro systems to animal studies of increasing complexity as well as complementing in silico approaches.