Background: Immunotherapy efficacy in esophageal squamous cell carcinoma (ESCC) is often limited by an immunosuppressive tumor microenvironment (TME). NLRC5, a key regulator of MHC-I antigen presentation, exhibits context-dependent roles in tumor immunity; however, its function in ESCC remains unclear. This study aimed to systematically investigate the expression pattern, prognostic value, and immunological role of NLRC5 in ESCC. Methods: An integrated analysis of bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq) data was performed using multiple cohorts, including The Cancer Genome Atlas, Gene Expression Omnibus, and an in-house ESCC cohort. Differential expression, survival analysis, immune infiltration estimation, and functional enrichment analyses were conducted to elucidate the role of NLRC5 in the tumor microenvironment. Results: NLRC5 was significantly upregulated in ESCC and its high expression independently predicted poor patient survival. Although NLRC5 expression was associated with increased CD8+ T cell infiltration, it was paradoxically accompanied by features of T-cell exhaustion and elevated expression of multiple immune checkpoints. Moreover, NLRC5-high tumors were enriched in transcriptional programs related to PANoptosis, indicating an additional immunosuppressive mechanism within the TME. Conclusions: NLRC5 is not only a prognostic biomarker but also a key modulator of an immune-active yet functionally suppressed tumor microenvironment in ESCC. These findings highlight NLRC5 as a potential therapeutic target for restoring effective antitumor immunity.

Cannabis use continues to rise in Canada, prompting concerns due to its potential impact on immune function. This study investigated the effect of a cannabis joint extract (CJE) on natural killer (NK) cells and explored the mechanisms underlying its potential anti-inflammatory properties. Peripheral blood mononuclear cells (PBMCs) were exposed to varying concentrations of CJE to assess cytotoxicity. Flow cytometry was employed to evaluate oxidative stress, autophagy, mitochondrial membrane potential, caspase-3 activation, and DNA damage. Additionally, NK cell cytotoxicity, migration, and adhesion were analyzed. Data indicated that CJE exposure led to dose-dependent cytotoxicity in NK cells, primarily through apoptosis. Specifically, at a concentration of 3 μg/mL, CJE significantly increased reactive oxygen species (ROS), autophagy markers, caspase activation, and DNA damage, while reducing mitochondrial membrane potential. Moreover, CJE impaired NK cell-mediated killing of HeLa cells, though their migratory and adhesive abilities were unaffected. These findings evidence that cannabis can detrimentally affect NK cell viability and function via mechanisms involving autophagy and caspase-dependent apoptosis.

Glioblastoma (GBM) is the most aggressive primary malignant brain tumor, and while chimeric antigen receptor-T (CAR-T) cell therapy has shown promise, its efficacy remains limited by antigen heterogeneity and immune escape. Here, we investigated the expression of B7 homolog 3 (B7-H3), epidermal growth factor receptor (EGFR), and interleukin-13 receptor alpha 2 (IL-13RA2) in GBM tissues and cell lines. Although all three antigens were highly expressed, sustained exposure to B7-H3 CAR-T cells led to significant B7-H3 downregulation but concurrent EGFR upregulation, revealing a potential immune escape mechanism. To address this heterogeneity, we engineered T cells to express an anti-B7-H3 CAR and secrete an EGFR-targeting bispecific T-cell engager (EGFR-BsTe). These B7-H3-CAR-T-EGFR-BsTe cells exerted dual functionality: direct B7-H3-dependent cytotoxicity and recruitment of unmodified T cells via secreted EGFR-BsTe to eliminate EGFR-expressing tumor cells. Notably, EGFR-BsTe secretion promoted CAR-T cell proliferation and effector differentiation. In orthotopic GBM xenograft models, including mixed tumors with heterogeneous antigen expression, B7-H3-CAR-T-EGFR-BsTe cells demonstrated superior antitumor activity and prolonged survival compared to conventional B7-H3 CAR-T cells. Quantitative analysis revealed that EGFR-BsTe secretion abrogated EGFR upregulation and enhanced B7-H3 downregulation in a target-dependent manner; however, efficacy was diminished when the CAR-Target (B7-H3) was absent on a substantial fraction of tumor cells. Our findings suggest that arming B7-H3 CAR-T cells with EGFR-targeting bispecific engagers represents a promising strategy to overcome antigen heterogeneity and improve therapeutic outcomes for GBM patients.