Glioblastoma (GBM) remains the most aggressive and lethal brain tumor in adults and poses significant challenges to patient survival. This review provides a comprehensive exploration of the molecular and genetic landscape of GBM, focusing on key oncogenic drivers, such as epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), and the PI3K/AKT/mTOR pathway, which are critical for tumorigenesis and progression. We delve into the role of epigenetic alterations, including DNA methylation and histone modifications, in driving therapy resistance and tumor evolution. The tumor microenvironment is known for its pivotal role in immune evasion, with tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells creating an immunosuppressive niche that sustains GBM growth. Emerging therapies, such as immunotherapies, oncolytic viral therapies, extracellular vesicle-based approaches, and non-coding RNA interventions, are highlighted as promising avenues to disrupt GBM pathogenesis. Advances in precision medicine and innovative technologies, including electric field therapy and locoregional treatments, are discussed for their potential to overcome the blood‒brain barrier and treatment resistance. Additionally, this review underscores the importance of metabolic reprogramming, particularly hypoxia-driven adaptations and altered lipid metabolism, in fueling GBM progression and influencing the therapeutic response. The role of glioma stem cells in tumor recurrence and resistance is also emphasized, highlighting the need for targeted therapeutic approaches. By integrating molecular targeting, immune energetics, and technological advancements, this review outlines a multidisciplinary framework for improving GBM treatment outcomes. Ultimately, the convergence of genetic, metabolic, and immune-based strategies offers transformative potential in GBM management, paving the way for increased patient survival and quality of life.

Previous work from our laboratory has demonstrated that during acute viral brain infection, glial cells modulate antiviral T cell effector responses through the PD-1: PD-L1 pathway, thereby limiting the deleterious consequences of unrestrained neuroinflammation. Here, we evaluated the PD-1: PD-L1 pathway in development of brain-resident memory T cells (bTRM) following murine cytomegalovirus (MCMV) infection. Flow cytometric analysis of immune cells was performed at 7, 14, and 30 days post-infection (dpi) to assess the shift of brain-infiltrating CD8+ T cell populations from short-lived effector cells (SLEC) to memory precursor effector cells (MPEC), as well as generation of bTRMs. In wild-type (WT) animals, we observed a switch in the phenotype of brain-infiltrating CD8+ T cell populations from KLRG1+ CD127− (SLEC) to KLRG1− CD127+ (MPEC) during transition from acute through chronic phases of infection. At 14 and 30 dpi, the majority of CD8+ T cells expressed CD127, a marker of memory cells. In contrast, fewer CD8+ T cells expressed CD127 within brains of infected, PD-L1 knockout (KO) animals. Notably, in WT mice, a large population of CD8+ T cells was phenotyped as CD103+ CD69+, markers of bTRM, and differences were observed in the numbers of these cells when compared to PD-L1 KOs. Immunohistochemical studies revealed that brain-resident CD103+ bTRM cells were localized to the parenchyma. Higher frequencies of CXCR3 were also observed among WT animals in contrast to PD-L1 KOs. Taken together, our results indicate that bTRMs are present within the CNS following viral infection and the PD-1: PD-L1 pathway plays a role in the generation of this brain-resident population.

Immune tolerance to allografts has been pursued for decades as an important goal in transplantation. Administration of apoptotic donor splenocytes effectively induces antigen-specific tolerance to allografts in murine studies. Here we show that two peritransplant infusions of apoptotic donor leukocytes under short-term immunotherapy with antagonistic anti-CD40 antibody 2C10R4, rapamycin, soluble tumor necrosis factor receptor and anti-interleukin 6 receptor antibody induce long-term (≥1 year) tolerance to islet allografts in 5 of 5 nonsensitized, MHC class I-disparate, and one MHC class II DRB allele-matched rhesus macaques. Tolerance in our preclinical model is associated with a regulatory network, involving antigen-specific Tr1 cells exhibiting a distinct transcriptome and indirect specificity for matched MHC class II and mismatched class I peptides. Apoptotic donor leukocyte infusions warrant continued investigation as a cellular, nonchimeric and translatable method for inducing antigen-specific tolerance in transplantation.

Conventional and cancer immunotherapies encompass diverse strategies to address various cancer types and stages. However, combining these approaches often encounters limitations such as non-specific targeting, resistance development, and high toxicity, leading to suboptimal outcomes in many cancers. The tumor microenvironment (TME) is orchestrated by intricate interactions between immune and non-immune cells dictating tumor progression. An innovative avenue in cancer therapy involves leveraging small molecules to influence a spectrum of resistant cell populations within the TME. Recent discoveries have unveiled a phenotypically diverse cohort of innate-like T (ILT) cells and tumor hybrid cells (HCs) exhibiting novel characteristics, including augmented proliferation, migration, resistance to exhaustion, evasion of immunosurveillance, reduced apoptosis, drug resistance, and heightened metastasis frequency. Leveraging small-molecule immunomodulators to target these immune players presents an exciting frontier in developing novel tumor immunotherapies. Moreover, combining small molecule modulators with immunotherapy can synergistically enhance the inhibitory impact on tumor progression by empowering the immune system to meticulously fine-tune responses within the TME, bolstering its capacity to recognize and eliminate cancer cells. This review outlines strategies involving small molecules that modify immune cells within the TME, potentially revolutionizing therapeutic interventions and enhancing the anti-tumor response.

The gastrointestinal (GI) tract redox environment, influenced by commensal microbiota and bacterial-derived metabolites, is crucial in shaping T-cell responses. Specifically, metabolites from gut microbiota (GM) exhibit robust anti-inflammatory effects, fostering the differentiation and regulation of CD8⁺ tissue-resident memory (TRM) cells, mucosal-associated invariant T (MAIT) cells, and stabilizing gut-resident Treg cells. Nitric oxide (NO), a pivotal redox mediator, emerges as a central regulator of T-cell functions and gut inflammation. NO impacts the composition of the gut microbiome, driving the differentiation of pro-inflammatory Th17 cells and exacerbating intestinal inflammation, and supports Treg expansion, showcasing its dual role in immune homeostasis. This review delves into the complex interplay between GI redox balance and GM metabolites, elucidating their profound impact on T-cell regulation. Additionally, it comprehensively emphasizes the critical role of GI redox, particularly reactive oxygen species (ROS) and NO, in shaping T-cell phenotype and functions. These insights offer valuable perspectives on disease mechanisms and potential therapeutic strategies for conditions associated with oxidative stress. Understanding the complex cross-talk between GI redox, GM metabolites, and T-cell responses provides valuable insights into potential therapeutic avenues for immune-mediated diseases, underscoring the significance of maintaining GI redox balance for optimal immune health.

The mTOR signaling pathway plays a pivotal and intricate role in the pathogenesis of glioblastoma, driving tumorigenesis and proliferation. Mutations or deletions in the PTEN gene constitutively activate the mTOR pathway by expressing growth factors EGF and PDGF, which activate their respective receptor pathways (e.g., EGFR and PDGFR). The convergence of signaling pathways, such as the PI3K-AKT pathway, intensifies the effect of mTOR activity. The inhibition of mTOR has the potential to disrupt diverse oncogenic processes and improve patient outcomes. However, the complexity of the mTOR signaling, off-target effects, cytotoxicity, suboptimal pharmacokinetics, and drug resistance of the mTOR inhibitors pose ongoing challenges in effectively targeting glioblastoma. Identifying innovative treatment strategies to address these challenges is vital for advancing the field of glioblastoma therapeutics. This review discusses the potential targets of mTOR signaling and the strategies of target-specific mTOR inhibitor development, optimized drug delivery system, and the implementation of personalized treatment approaches to mitigate the complications of mTOR inhibitors. The exploration of precise mTOR-targeted therapies ultimately offers elevated therapeutic outcomes and the development of more effective strategies to combat the deadliest form of adult brain cancer and transform the landscape of glioblastoma therapy.