Enhancement of CD70-specific CAR T treatment by IFN-γ released from oHSV-1-infected glioblastoma

Altered cancer metabolism and implications for next-generation CAR T-cell therapies

This review critically examines the evolving landscape of chimeric antigen receptor (CAR) T-cell therapy in treating solid tumors, with a particular focus on the metabolic challenges within the tumor microenvironment. CAR T-cell therapy has demonstrated remarkable success in hematologic malignancies, yet its efficacy in solid tumors remains limited. A significant barrier is the hostile milieu of the tumor microenvironment, which impairs CAR T-cell survival and function. This review delves into the metabolic adaptations of cancer cells and their impact on immune cells, highlighting the competition for nutrients and the accumulation of immunosuppressive metabolites. It also explores emerging strategies to enhance CAR T-cell metabolic fitness and persistence, including genetic engineering and metabolic reprogramming. An integrated approach, combining metabolic interventions with CAR T-cell therapy, has the potential to overcome these constraints and improve therapeutic outcomes in solid tumors.

OH2 oncolytic virus: A novel approach to glioblastoma intervention through direct targeting of tumor cells and augmentation of anti-tumor immune responses

Glioblastoma (GBM), the deadliest central nervous system cancer, presents a poor prognosis and scant therapeutic options. Our research spotlights OH2, an oncolytic viral therapy derived from herpes simplex virus 2 (HSV-2), which demonstrates substantial antitumor activity and favorable tolerance in GBM. The extraordinary efficacy of OH2 emanates from its unique mechanisms: it selectively targets tumor cells replication, powerfully induces cytotoxic DNA damage stress, and kindles anti-tumor immune responses. Through single-cell RNA sequencing analysis, we discovered that OH2 not only curtails the proliferation of cancer cells and tumor-associated macrophages (TAM)-M2 but also bolsters the infiltration of macrophages, CD4+ and CD8+ T cells. Further investigation into molecular characteristics affecting OH2 sensitivity revealed potential influencers such as TTN, HMCN2 or IRS4 mutations, CDKN2A/B deletion and IDO1 amplification. This study marks the first demonstration of an HSV-2 derived OV's effectiveness against GBM. Significantly, these discoveries have driven the initiation of a phase I/II clinical trial (ClinicalTrials.gov: NCT05235074). This trial is designed to explore the potential of OH2 as a therapeutic option for patients with recurrent central nervous system tumors following surgical intervention.

The development of chimeric antigen receptor T-cells against CD70 for renal cell carcinoma treatment

In this study, we investigated CD70 as a promising target for renal cell carcinoma (RCC) therapy and developed a potent chimeric antigen receptor T (CAR-T) cells for potential clinical testing. CD70, found to be highly expressed in RCC tumors, was associated with decreased survival. We generated CAR-T cells expressing VHH sequence of various novel nanobodies from immunized alpaca and a single-chain variable fragment (scFv) derived from human antibody (41D12). In our in vitro experiments, anti-CD70 CAR-T cells effectively eliminated CD70-positive tumor cells while sparing CD70-negative cells. The nanobody-based CAR-T cells demonstrated significantly higher production of cytokines such as IL-2, IFN-γ and TNF-ɑ during co-culture, indicating their potential for enhanced functionality. In xenograft mouse model, these CAR-T cells exhibited remarkable anti-tumor activity, leading to the eradication of RCC tumor cells. Importantly, human T cell expansion after infusion was significantly higher in the VHH groups compared to the scFv CAR-T group. Upon re-challenging mice with RCC tumor cells, the VHH CAR-T treated group remained tumor-free, suggesting a robust and long-lasting anti-tumor response. These findings provide strong support for the potential of nanobody-based CD70 CAR-T cells as a promising therapeutic option for RCC. This warrants further development and consideration for future clinical trials and applications.

Cytokine Modification of Adoptive Chimeric Antigen Receptor Immunotherapy for Glioblastoma

Chimeric antigen receptor (CAR) cell-based therapies have demonstrated limited success in solid tumors, including glioblastoma (GBM). GBMs exhibit high heterogeneity and create an immunosuppressive tumor microenvironment (TME). In addition, other challenges exist for CAR therapy, including trafficking and infiltration into the tumor site, proliferation, persistence of CARs once in the tumor, and reduced functionality, such as suboptimal cytokine production. Cytokine modification is of interest, as one can enhance therapy efficacy and minimize off-target toxicity by directly combining CAR therapy with cytokines, antibodies, or oncolytic viruses that alter cytokine response pathways. Alternatively, one can genetically modify CAR T-cells or CAR NK-cells to secrete cytokines or express cytokines or cytokine receptors. Finally, CARs can be genetically altered to augment or suppress intracellular cytokine signaling pathways for a more direct approach. Codelivery of cytokines with CARs is the most straightforward method, but it has associated toxicity. Alternatively, combining CAR therapy with antibodies (e.g., anti-IL-6, anti-PD1, and anti-VEGF) or oncolytic viruses has enhanced CAR cell infiltration into GBM tumors and provided proinflammatory signals to the TME. CAR T- or NK-cells secreting cytokines (e.g., IL-12, IL-15, and IL-18) have shown improved efficacy within multiple GBM subtypes. Likewise, expressing cytokine-modulating receptors in CAR cells that promote or inhibit cytokine signaling has enhanced their activity. Finally, gene editing approaches are actively being pursued to directly influence immune signaling pathways in CAR cells. In this review, we summarize these cytokine modification methods and highlight any existing gaps in the hope of catalyzing an improved generation of CAR-based therapies for glioblastoma.

Optimizing CAR-T Therapy for Glioblastoma

Chimeric antigen receptor T-cell therapies have transformed the management of hematologic malignancies but have not yet demonstrated consistent efficacy in solid tumors. Glioblastoma is the most common primary malignant brain tumor in adults and remains a major unmet medical need. Attempts at harnessing the potential of chimeric antigen receptor T-cell therapy for glioblastoma have resulted in glimpses of promise but have been met with substantial challenges. In this focused review, we discuss current and future strategies being developed to optimize chimeric antigen receptor T cells for efficacy in patients with glioblastoma, including the identification and characterization of new target antigens, reversal of T-cell dysfunction with novel chimeric antigen receptor constructs, regulatable platforms, and gene knockout strategies, and the use of combination therapies to overcome the immune-hostile microenvironment.

Rabies virus glycoprotein 29 (RVG29) promotes CAR-T immunotherapy for glioma

Chimeric antigen receptor T cell (CAR-T) therapy has limited efficacy for treating glioma because of the infiltrative nature of the blood-brain barrier (BBB) and T cell exhaustion. Conjugation with rabies virus glycoprotein (RVG) 29 enhances the brain-related efficacy of various agents. Here we assess whether RVG enhances the ability of CAR-T cells to cross the BBB and improves their immunotherapy. We generated 70R CAR-T cells (anti-CD70 CAR-T modified with RVG29) and validated their tumor-killing efficacy in vitro and in vivo. We validated their effects on tumor regression in a human glioma mouse orthotopic xenograft model as well as in patient-derived orthotopic xenograft (PDOX) models. The signaling pathways activated in 70R CAR-T cells were revealed by RNA sequencing. The 70R CAR-T cells we generated showed effective antitumor function against CD70+ glioma cells both in vitro and in vivo. 70R CAR-T cells were better able to cross the BBB into the brain than CD70 CAR-T cells under the same treatment conditions. Moreover, 70R CAR-T cells significantly promote the regression of glioma xenografts and improve the physical characteristics of mice without causing overt adverse effects. RVG modification enables CAR-T cells to cross the BBB, and stimulation with glioma cells induces 70R CAR-T cells to expand in a resting state. The modification of RVG29 has a positive impact on CAR-T therapy for brain tumors and may have potential in CAR-T therapy for glioma.

Hallmarks of the Tumour Microenvironment of Gliomas and Its Interaction with Emerging Immunotherapy Modalities

Gliomas are aggressive, primary central nervous system tumours arising from glial cells. Glioblastomas are the most malignant. They are known for their poor prognosis or median overall survival. The current standard of care is overwhelmed by the heterogeneous, immunosuppressive tumour microenvironment promoting immune evasion and tumour proliferation. The advent of immunotherapy with its various modalities-immune checkpoint inhibitors, cancer vaccines, oncolytic viruses and chimeric antigen receptor T cells and NK cells-has shown promise. Clinical trials incorporating combination immunotherapies have overcome the microenvironment resistance and yielded promising survival and prognostic benefits. Rolling these new therapies out in the real-world scenario in a low-cost, high-throughput manner is the unmet need of the hour. These will have practice-changing implications to the glioma treatment landscape. Here, we review the immunobiological hallmarks of the TME of gliomas, how the TME evades immunotherapies and the work that is being conducted to overcome this interplay.

Chimeric Antigen Receptor T Cells in Glioblastoma-Current Concepts and Promising Future

Glioblastoma (GBM) is a highly aggressive primary brain tumor that is largely refractory to treatment and, therefore, invariably relapses. GBM patients have a median overall survival of 15 months and, given this devastating prognosis, there is a high need for therapy improvement. One of the therapeutic approaches currently tested in GBM is chimeric antigen receptor (CAR)-T cell therapy. CAR-T cells are genetically altered T cells that are redirected to eliminate tumor cells in a highly specific manner. There are several challenges to CAR-T cell therapy in solid tumors such as GBM, including restricted trafficking and penetration of tumor tissue, a highly immunosuppressive tumor microenvironment (TME), as well as heterogeneous antigen expression and antigen loss. In addition, CAR-T cells have limitations concerning safety, toxicity, and the manufacturing process. To date, CAR-T cells directed against several target antigens in GBM including interleukin-13 receptor alpha 2 (IL-13Rα2), epidermal growth factor receptor variant III (EGFRvIII), human epidermal growth factor receptor 2 (HER2), and ephrin type-A receptor 2 (EphA2) have been tested in preclinical and clinical studies. These studies demonstrated that CAR-T cell therapy is a feasible option in GBM with at least transient responses and acceptable adverse effects. Further improvements in CAR-T cells regarding their efficacy, flexibility, and safety could render them a promising therapy option in GBM.

Gene Targets of CAR-T Cell Therapy for Glioblastoma

Glioblastoma (GBM) is an aggressive primary brain tumor with a poor prognosis following conventional therapeutic interventions. Moreover, the blood-brain barrier (BBB) severely impedes the permeation of chemotherapy drugs, thereby reducing their efficacy. Consequently, it is essential to develop novel GBM treatment methods. A novel kind of pericyte immunotherapy known as chimeric antigen receptor T (CAR-T) cell treatment uses CAR-T cells to target and destroy tumor cells without the aid of the antigen with great specificity and in a manner that is not major histocompatibility complex (MHC)-restricted. It has emerged as one of the most promising therapy techniques with positive clinical outcomes in hematological cancers, particularly leukemia. Due to its efficacy in hematologic cancers, CAR-T cell therapy could potentially treat solid tumors, including GBM. On the other hand, CAR-T cell treatment has not been as therapeutically effective in treating GBM as it has in treating other hematologic malignancies. CAR-T cell treatments for GBM have several challenges. This paper reviewed the use of CAR-T cell therapy in hematologic tumors and the selection of targets, difficulties, and challenges in GBM.

Oncolytic virus therapy for malignant gliomas: entering the new era

INTRODUCTION

To overcome the challenge of treating malignant brain tumors, oncolytic viruses (OVs) represent an innovative therapeutic approach, featuring unique mechanisms of action. The recent conditional approval of the oncolytic herpes simplex virus G47Δ as a therapeutic for malignant brain tumors marked a significant milestone in the long history of OV development in neuro-oncology.

AREAS COVERED

This review summarizes the results of recently completed and active clinical studies that investigate the safety and efficacy of different OV types in patients with malignant gliomas. The changing landscape of the OV trial design includes expansion of subjects to newly diagnosed tumors and pediatric populations. A variety of delivery methods and new routes of administration are vigorously tested to optimize tumor infection and overall efficacy. New therapeutic strategies such as combination with immunotherapies are proposed that take advantage of the characteristics of OV therapy as an immunotherapy. Preclinical studies of OV have been active and aim to translate new OV strategies to the clinic.

EXPERT OPINION

For the next decade, clinical trials and preclinical and translational research will continue to drive the development of innovative OV treatments for malignant gliomas and benefit patients and define new OV biomarkers.

The gamble between oncolytic virus therapy and IFN

Various studies are being conducted on oncolytic virotherapy which one of the mechanisms is mediating interferon (IFN) production by it exerts antitumor effects. The antiviral effect of IFN itself has a negative impact on the inhibition of oncolytic virus or tumor eradication. Therefore, it is very critical to understand the mechanism of IFN regulation by oncolytic viruses, and to define its mechanism is of great significance for improving the antitumor effect of oncolytic viruses. This review focuses on the regulatory mechanisms of IFNs by various oncolytic viruses and their combination therapies. In addition, the exerting and the producing pathways of IFNs are briefly summarized, and some current issues are put forward.