Macrophage polarization contributes to the efficacy of an oncolytic HSV-1 targeting human uveal melanoma in a murine xenograft model

Investigating the potential of oncolytic viruses in the treatment of melanoma: where do we go from here?

Oncolytic viruses (OVs) can destroy cancer cells without harming healthy cells. This review explores the mechanisms by which OVs operate and the methods of delivering them. Melanoma is a common type of skin cancer with increasing prevalence in the UK; therefore, finding effective strategies to combat the disease is paramount. To understand the potential of OVs in treating melanoma, different types of viruses will be reviewed. Talimogene laherparepvec (T-VEC) is the only OV to be approved for treating melanoma; this review aims to understand the efficacy of T-VEC as a monotherapy and combined with other treatments. There is substantial evidence to support the use of OVs in treating melanoma by synthesizing the current perspectives of their use where they proved to be effective in clinical trials, as monotherapies and in combination with other treatments, as well as exciting innovative ventures using novel virus species. Gaps are also highlighted in the research, such as determining the influence that cancer gene mutational status has on how the tumour cells react to treatment, a concept that should also be considered in future research.

Oncolytic Viruses and Immunotherapy for the Treatment of Uveal Melanoma and Retinoblastoma: The Current Landscape and Novel Advances

Intraocular malignant tumors are rare; however, they can cause serious life-threatening complications. Uveal melanoma (UM) and retinoblastoma (RB) are the most common intraocular tumors in adults and children, respectively, and come with a great disease burden. For many years, several different treatment modalities for UM and RB have been proposed, with chemotherapy for RB cases and plaque radiation therapy for localized UM as first-line treatment options. Extraocular extension, recurrence, and metastasis constitute the major challenges of conventional treatments. To overcome these obstacles, immunotherapy, which encompasses different treatment options such as oncolytic viruses, antibody-mediated immune modulations, and targeted immunotherapy, has shown great potential as a novel therapeutic tool for cancer therapy. These anti-cancer treatment options provide numerous advantages such as selective cancer cell death and the promotion of an anti-tumor immune response, and they prove useful in preventing vision impairment due to macular and/or optic disc involvement. Numerous factors such as the vector choice, route of administration, dosing, and patient characteristics must be considered when engineering an oncolytic virus or other forms of immunotherapy vectors. This manuscript provides an in-depth review of the molecular design of oncolytic viruses (e.g., virus capsid proteins and encapsulation technologies, vectors for delivery, cell targeting) and immunotherapy. The most recent advances in preclinical- and clinical-phase studies are further summarized. The recent developments in virus-like drug conjugates (i.e., AU011), oncolytic viruses for metastatic UM, and targeted immunotherapies have shown great results in clinical trials for the future clinical application of these novel technologies in the treatment algorithm of certain intraocular tumors.

Olaparib Enhances the Efficacy of Third-Generation Oncolytic Adenoviruses Against Glioblastoma by Modulating DNA Damage Response and p66shc-Induced Apoptosis

AIMS

Patients with glioblastoma multiforme (GBM) do not benefit from current cancer treatments, and their prognosis is dismal. This study aimed to investigate the potential synergistic effects of TS-2021, a third-generation oncolytic adenovirus, combined with the PARP inhibitor olaparib in GBM.

METHODS

TS-2021's impact on p66shc-induced apoptosis, DNA damage response, and poly (ADP-ribose) polymerase (PARP) activation was evaluated in GBM cells. The synergistic effect of TS-2021 and olaparib was examined in GBM cell lines and an immunocompetent mouse model of GBM. Mechanistic studies focused on the role of p66shc phosphorylation in the observed effects.

RESULTS

TS-2021 triggered p66shc-induced apoptosis, DNA damage response, and PARP activation. The combination of TS-2021 and olaparib synergistically increased cell apoptosis and DNA damage and reduced PARP expression compared to monotherapy. Olaparib promoted TS-2021 replication and release in GBM cells. Mechanistically, olaparib combined with TS-2021 upregulated p66shc phosphorylation, enhancing tumor cell apoptosis. In vivo, the combination therapy inhibited tumor growth and prolonged survival, confirming the synergistic effect.

CONCLUSION

This study is the first to suggest that TS-2021 sensitizes GBM cells with wild-type BRCA1/2 to olaparib. The combination of TS-2021 and olaparib shows a synergistic therapeutic effect against GBM, providing a promising treatment strategy.

Oncolytic virus and tumor-associated macrophage interactions in cancer immunotherapy

Oncolytic viruses (OV) are a promising strategy in cancer immunotherapy. Their capacity to promote anti-tumoral immunity locally raises hope that cancers unresponsive to current immunotherapy approaches could be tackled more efficiently. In this context, tumor-associated macrophages (TAM) must be considered because of their pivotal role in cancer immunity. Even though TAM tend to inhibit anti-tumoral responses, their ability to secrete pro-inflammatory cytokines and phagocytose cancer cells can be harnessed to promote therapeutic cancer immunity. OVs have the potential to promote TAM pro-inflammatory functions that favor anti-tumoral immunity. But in parallel, TAM pro-inflammatory functions induce OV clearance in the tumor, thereby limiting OV efficacy and highlighting that the interaction between OV and TAM is a double edge sword. Moreover, engineered OVs were recently developed to modulate specific TAM functions such as phagocytic activity. The potential of circulating monocytes to deliver OV into the tumor after intravenous administration is also emerging. In this review, we will present the interaction between OV and TAM, the potential of engineered OV to modulate specific TAM functions, and the promising role of circulating monocytes in OV delivery to the tumor.

Uveal Melanoma: Comprehensive Review of Its Pathophysiology, Diagnosis, Treatment, and Future Perspectives

Uveal melanoma (UM) is the most common intraocular malignancy in adults. Recent advances highlight the role of tumor-derived extracellular vesicles (TEV) and circulating hybrid cells (CHC) in UM tumorigenesis. Bridged with liquid biopsies, a novel technology that has shown incredible performance in detecting cancer cells or products derived from tumors in bodily fluids, it can significantly impact disease management and outcome. The aim of this comprehensive literature review is to provide a summary of current knowledge and ongoing advances in posterior UM pathophysiology, diagnosis, and treatment. The first section of the manuscript discusses the complex and intricate role of TEVs and CHCs. The second part of this review delves into the epidemiology, etiology and risk factors, clinical presentation, and prognosis of UM. Third, current diagnostic methods, ensued by novel diagnostic tools for the early detection of UM, such as liquid biopsies and artificial intelligence-based technologies, are of paramount importance in this review. The fundamental principles, limits, and challenges associated with these diagnostic tools, as well as their potential as a tracker for disease progression, are discussed. Finally, a summary of current treatment modalities is provided, followed by an overview of ongoing preclinical and clinical research studies to provide further insights on potential biomolecular pathway alterations and therapeutic targets for the management of UM. This review is thus an important resource for all healthcare professionals, clinicians, and researchers working in the field of ocular oncology.

The Future of Checkpoint Inhibitors in Uveal Melanoma: A Narrative Review

INTRODUCTION

Immune checkpoint inhibitors have made tremendous progress over the last decade in the treatment of cutaneous melanoma, but their application in uveal melanoma treatment is less successful, owing in part to the immunological privilege of the eye and the liver, the most frequent site of metastasis. Nevertheless, the therapeutic outcomes reported currently are less pessimistic.

METHODS

In this review, we provide an overview of recent studies of immune checkpoint inhibitors in uveal melanoma and its metastasis and classify studies in this field into three groups: monotherapy of immune checkpoint inhibitors, dual-agent immune checkpoint inhibitors, and immune checkpoint inhibitors combined with other systemic or regional therapies.

RESULTS

Briefly, monotherapy with immune checkpoint inhibitors performed poorly. Dual-agent immune checkpoint inhibitors had slightly better outcomes than traditional treatments, especially in specific patient populations. As for the combination therapy, the combination with other systemic therapies did not show superiority over dual-agent immune checkpoint inhibitors, but combination with hepatic regional therapies was quite promising. Moreover, research on emerging checkpoints is currently limited to the stage of mechanistic studies.

CONCLUSION

We propose that immune checkpoint inhibitors remain alternative treatments for patients with uveal melanoma, but factors such as cost-effectiveness should also be taken into account. The combination therapy with immune checkpoint inhibitors deserves to be further explored.

Uveal melanoma modeling in mice and zebrafish

Despite extensive research and refined therapeutic options, the survival for metastasized uveal melanoma (UM) patients has not improved significantly. UM, a malignant tumor originating from melanocytes in the uveal tract, can be asymptomatic and small tumors may be detected only during routine ophthalmic exams; making early detection and treatment difficult. UM is the result of a number of characteristic somatic alterations which are associated with prognosis. Although UM morphology and biology have been extensively studied, there are significant gaps in our understanding of the early stages of UM tumor evolution and effective treatment to prevent metastatic disease remain elusive. A better understanding of the mechanisms that enable UM cells to thrive and successfully metastasize is crucial to improve treatment efficacy and survival rates. For more than forty years, animal models have been used to investigate the biology of UM. This has led to a number of essential mechanisms and pathways involved in UM aetiology. These models have also been used to evaluate the effectiveness of various drugs and treatment protocols. Here, we provide an overview of the molecular mechanisms and pharmacological studies using mouse and zebrafish UM models. Finally, we highlight promising therapeutics and discuss future considerations using UM models such as optimal inoculation sites, use of BAP1mut-cell lines and the rise of zebrafish models.

Autoimmune Disease-Related Dry Eye Diseases and Their Placement Under the Revised Classification Systems: An Update

Dry eye disease (DED) is a chronic and progressive disorder involving the ocular surface, characterized by disturbances in tear film composition, instability of the tear film, and inflammation of the ocular surface. There are two forms of DED: aqueous-deficient dry eye (ADDE) and evaporative dry eye (EDE). Autoimmune diseases are systemic disorders involving multiple organs, including the eyes, and have a significant impact on DED. There have been multiple studies demonstrating the relation between autoimmune diseases and DED. This article reviews the current knowledge regarding the epidemiological characteristics, pathogenesis, and treatments of autoimmune disease-related DED.

Oncolytic HSV-1 suppresses cell invasion through downregulating Sp1 in experimental glioblastoma

Gliomas are highly aggressive intracranial tumors that are difficult to resect and have high lethality and recurrence rates. According to WHO grading criteria, glioblastoma with wild-type IDH1 has a poorer prognosis than WHO grade 4 IDH-mutant astrocytomas. To date, no effective therapeutic strategies have been developed to treat glioblastoma. Clinical trials have shown that herpes simplex virus (HSV)-1 is the safest and most efficacious oncolytic virus against glioblastoma, but the molecular antitumor mechanism of action of HSV-1 has not yet been determined. Deletion of the γ34.5 and ICP47 genes from a strain of HSV-1 yielded the oncolytic virus, oHSV-1, which reduced glioma cell viability, migration, and invasive capacity, as well as the growth of microvilli. Infected cell polypeptide 4 (ICP4) expressed by oHSV-1 was found to suppress the expression of the transcription factor Sp1, reducing the expression of host invasion-related genes. In vivo, oHSV-1 showed significant antitumor effects by suppressing the expression of Sp1 and invasion-associated genes, highly expressed in high-grade glioblastoma tissue specimens. These findings indicate that Sp1 may be a molecular marker predicting the antitumor effects of oHSV-1 in the treatment of glioma and that oHSV-1 suppresses host cell invasion through the ICP4-mediated downregulation of Sp1.

Enhancing the immune effect of oHSV-1 therapy through TLR3 signaling in uveal melanoma

PURPOSE

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults, with patients having a low overall survival rate. Oncolytic viruses (OVs) have been shown effective as monotherapy or combined with immunotherapy in the treatment of UM. Oncolytic herpes simplex type I virus (oHSV-1) was found to alter gene expression and immune function in UMs. We investigated whether a combination treatment would be more effective in treating UM and reactive immune cells.

METHODS

RNA sequencing analysis were used to identify the effect of oHSV-1 infection in UM cells and protein changes were validated by western blot. Cell viability assays were performed through UM cell lines (MUM2B, 92.1, and MP41) and retinal pigment epithelial cell line (ARPE-19) to identify the efficacy and safety of the combination treatment. Western blot, qRT-PCR, cell viability assay and immunocytochemistry were performed to discover the reactivation of immune cells (U937 and HMC3).

RESULTS

Through RNA sequencing analysis and in vitro molecular biology assays, this study tested the ability of oHSV-1 combined with the TLR3 agonist poly(I:C) to re-activate the TLR3 meditated NF-ƙB signaling pathway and further increase the anti-tumor activity of UM cells and macrophages, including the stimulation of macrophage polarization and proliferation.

CONCLUSIONS

These findings indicate that the treatment of UM with a combination of oHSV-1 and poly(I:C) generates immune responses and enhances anti-tumoral activity, suggesting the need for further investigations and clinical trials of this combination.

Recent Advances and Challenges in Uveal Melanoma Immunotherapy

Simple Summary

Uveal melanoma is the most common primary intraocular malignancy in adults. Although it can be controlled locally, half of the patients still develop metastases. To date, there have been no standard therapeutic strategies for the prevention or treatment of metastases. Existing therapies, such as chemotherapy and targeted therapies, induce only minimal responses. This review focuses on newly published research on immunotherapy. We highlight expanding treatments and their clinical outcomes, as well as propose promising new treatments and feasible checkpoints. Based on these findings, we provide innovative insights into feasible strategies for the treatment of patients with uveal melanoma.

Abstract

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Compared to cutaneous melanoma (CM), which mainly harbors BRAF or NRAS mutations, UM predominantly harbors GNAQ or GNA11 mutations. Although primary UM can be controlled locally, approximately 50% of patients still develop metastases. To date, there have been no standard therapeutic strategies for the prevention or treatment of metastases. Unfortunately, chemotherapy and targeted therapies only induce minimal responses in patients with metastatic UM, with a median survival time of only 4–5 months after metastasis detection. Immunotherapy agents, such as immune checkpoint inhibitors, have achieved pioneering outcomes in CM but have shown limited effects in UM. Researchers have explored several feasible checkpoints to identify options for future therapies. Cancer vaccines have shown little in the way of therapeutic benefit in patients with UM, and there are few ongoing trials providing favorable evidence, but adoptive cell transfer-related therapies seem promising and deserve further investigation. More recently, the immune-mobilizing monoclonal T-cell receptor against the cancer molecule tebentafusp showed impressive antitumor effects. Meanwhile, oncolytic viruses and small molecule inhibitors have also gained ground. This review highlights recent progress in burgeoning treatments and provides innovative insights on feasible strategies for the treatment of UM.

Cutting both ways: the innate immune response to oncolytic virotherapy

Oncolytic viruses (OVs), above and beyond infecting and lysing malignant cells, interact with the immune system in complex ways that have important therapeutic significance. While investigation into these interactions is still in its early stages, important insights have been made over the past two decades that will help improve the clinical efficacy of OV-based management strategies in cancer care moving forward. The inherent immunosuppression that defines the tumor microenvironment can be modified by OV infection, and the subsequent recruitment and activation of innate immune cells, in particular, is central to this. Indeed, neutrophils, macrophages, natural killer cells, and dendritic cells, as well as other populations such as myeloid-derived suppressor cells, are key to the immune escape that allows tumors to survive, but their natural response to infection can be exploited by virotherapy. While stimulation of innate immune cells by OVs can initiate antitumor responses, related antiviral activity can limit virus spread and direct cytopathogenic effects. In this review, we highlight how each innate immune cell population influences this balance of antitumor and antiviral forces during virotherapy, some of the important molecular pathways that have been identified, and specific therapeutic targets that have emerged through this work. We discuss the importance of OV-based combination therapies in optimizing antiviral and antitumor innate immune responses stimulated by virotherapy toward tumor eradication, and how these processes vary depending on the tumor and OV in question. Rather than concentrating on a particular OV species in the review, we present the range of effects that have been documented across OV types to emphasize the context-specific nature of these interactions and how this is important in the design of future OV-based treatment approaches.

Killers on the loose: Immunotherapeutic strategies to improve NK cell-based therapy for cancer treatment

Natural killer (NK) cells are innate lymphocytes that control tumor progression by not only directly killing cancer cells, but also by regulating other immune cells, helping to orchestrate a coordinated anti-tumor response. However, despite the tremendous potential that this cell type has, the clinical results obtained from diverse NK cell-based immunotherapeutic strategies have been, until recent years, rather modest. The intrinsic regulatory mechanisms that are involved in the control of their activation as well as the multiple mechanisms that tumor cells have developed to escape NK cell-mediated cytotoxicity likely account for the unsatisfactory clinical outcomes. The current approaches to improve long-term NK cell function are centered on modulating different molecules involved in both the activation and inhibition of NK cells, and the latest data seems to advocate for combining strategies that target multiple aspects of NK cell regulation. In this review, we summarize the different strategies (such as engineered NK cells, CAR-NK, NK cell immune engagers) that are currently being used to take advantage of this potent and complex immune cell.

The Multifaceted Role of Macrophages in Oncolytic Virotherapy

One of the cancer hallmarks is immune evasion mediated by the tumour microenvironment (TME). Oncolytic virotherapy is a form of immunotherapy based on the application of oncolytic viruses (OVs) that selectively replicate in and induce the death of tumour cells. Virotherapy confers reciprocal interaction with the host’s immune system. The aim of this review is to explore the role of macrophage-mediated responses in oncolytic virotherapy efficacy. The approach was to study current scientific literature in this field in order to give a comprehensive overview of the interactions of OVs and macrophages and their effects on the TME. The innate immune system has a central influence on the TME; tumour-associated macrophages (TAMs) generally have immunosuppressive, tumour-supportive properties. In the context of oncolytic virotherapy, macrophages were initially thought to predominantly contribute to anti-viral responses, impeding viral spread. However, macrophages have now also been found to mediate transport of OV particles and, after TME infiltration, to be subjected to a phenotypic shift that renders them pro-inflammatory and tumour-suppressive. These TAMs can present tumour antigens leading to a systemic, durable, adaptive anti-tumour immune response. After phagocytosis, they can recirculate carrying tissue-derived proteins, which potentially enables the monitoring of OV replication in the TME. Their role in therapeutic efficacy is therefore multifaceted, but based on research applying relevant, immunocompetent tumour models, macrophages are considered to have a central function in anti-cancer activity. These novel insights hold important clinical implications. When optimised, oncolytic virotherapy, mediating multifactorial inhibition of cancer immune evasion, could contribute to improved patient survival.

Targeting Tumor-Associated Antigen: A Promising CAR-T Therapeutic Strategy for Glioblastoma Treatment

Chimeric antigen receptor T cells (CAR-T) therapy is a prospective therapeutic strategy for blood cancers tumor, especially leukemia, but it is not effective for solid tumors. Glioblastoma (GBM) is a highly immunosuppressive and deadly malignant tumor with poor responses to immunotherapies. Although CAR-T therapeutic strategies were used for glioma in preclinical trials, the current proliferation activity of CAR-T is not sufficient, and malignant glioma usually recruit immunosuppressive cells to form a tumor microenvironment that hinders CAR-T infiltration, depletes CAR-T, and impairs their efficacy. Moreover, specific environments such as hypoxia and nutritional deficiency can hinder the killing effect of CAR-T, limiting their therapeutic effect. The normal brain lack lymphocytes, but CAR-T usually can recognize specific antigens and regulate the tumor immune microenvironment to increase and decrease pro- and anti-inflammatory factors, respectively. This increases the number of T cells and ultimately enhances anti-tumor effects. CAR-T therapy has become an indispensable modality for glioma due to the specific tumor-associated antigens (TAAs). This review describes the characteristics of CAR-T specific antigen recognition and changing tumor immune microenvironment, as well as ongoing research into CAR-T therapy targeting TAAs in GBM and their potential clinical application.