Gene Targets of CAR-T Cell Therapy for Glioblastoma

HER2-targeting CAR-T cells show highly efficient anti-tumor activity against glioblastoma both in vitro and in vivo

Glioblastoma (GBM) is the most common and aggressive malignant primary brain tumor in adults. Current treatment options for GBM include surgical resection, radiation, and chemotherapy, which predominantly slow cancer growth and reduce symptoms, resulting in a 5-year survival rate of no more than 10%. Chimeric antigen receptor (CAR) T-cell therapy is a new class of cellular immunotherapy that has made great progress in treating malignant tumors. Human epidermal growth factor receptor 2 (HER2) is overexpressed in GBM and may provide a potential therapeutic target for GBM treatment. In this study, we constructed third-generation CAR-T cells targeting the HER2 antigen in GBM. HER2-CAR-T cells showed effective anti-tumor activity both in vitro and in vivo. Furthermore, HER2-specific CAR-T cells exhibited strong cytotoxicity and cytokine-secreting abilities against GBM cells in vitro. Anti-HER2 CAR-T cells also exhibited increased cytotoxicity with increasing effector-to-target ratios. Anti-HER2 CAR-T cells delivered via peritumoral injection successfully stunted tumor progression in vivo. Moreover, peritumoral intravenous administration of anti-HER2 CAR-T cells resulted in therapeutic improvement against GBM cells compared with intravenous administration. In conclusion, our study shows that HER2 CAR-T cells represent an emerging immunotherapy for treating GBM.

Deciphering Glioblastoma: Fundamental and Novel Insights into the Biology and Therapeutic Strategies of Gliomas

Gliomas constitute a diverse and complex array of tumors within the central nervous system (CNS), characterized by a wide range of prognostic outcomes and responses to therapeutic interventions. This literature review endeavors to conduct a thorough investigation of gliomas, with a particular emphasis on glioblastoma (GBM), beginning with their classification and epidemiological characteristics, evaluating their relative importance within the CNS tumor spectrum. We examine the immunological context of gliomas, unveiling the intricate immune environment and its ramifications for disease progression and therapeutic strategies. Moreover, we accentuate critical developments in understanding tumor behavior, focusing on recent research breakthroughs in treatment responses and the elucidation of cellular signaling pathways. Analyzing the most novel transcriptomic studies, we investigate the variations in gene expression patterns in glioma cells, assessing the prognostic and therapeutic implications of these genetic alterations. Furthermore, the role of epigenetic modifications in the pathogenesis of gliomas is underscored, suggesting that such changes are fundamental to tumor evolution and possible therapeutic advancements. In the end, this comparative oncological analysis situates GBM within the wider context of neoplasms, delineating both distinct and shared characteristics with other types of tumors.

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.

Immune Escape in Glioblastoma: Mechanisms of Action and Implications for Immune Checkpoint Inhibitors and CAR T-Cell Therapy

Glioblastoma, the most common primary brain cancer in adults, is characterized by a poor prognosis and resistance to standard treatments. The advent of immunotherapy has revolutionized the treatment of several cancers in recent years but has failed to demonstrate benefit in patients with glioblastoma. Understanding the mechanisms by which glioblastoma exerts tumor-mediated immune suppression in both the tumor microenvironment and the systemic immune landscape is a critical step towards developing effective immunotherapeutic strategies. In this review, we discuss the current understanding of immune escape mechanisms in glioblastoma that compromise the efficacy of immunotherapies, with an emphasis on immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy. In parallel, we review data from preclinical studies that have identified additional therapeutic targets that may enhance overall treatment efficacy in glioblastoma when administered alongside existing immunotherapies.