Hypoxic glioblastoma-cell-derived extracellular vesicles impair cGAS-STING activity in macrophages.

BACKGROUND: Solid tumors such as glioblastoma (GBM) exhibit hypoxic zones that are associated with poor prognosis and immunosuppression through multiple cell intrinsic mechanisms. However, release of extracellular vesicles (EVs) has the potential to transmit molecular cargos between cells. If hypoxic cancer cells use EVs to suppress functions of macrophages under adequate oxygenation, this could be an important underlying mechanism contributing to the immunosuppressive and immunologically cold tumor microenvironment of tumors such as GBM. METHODS: EVs were isolated by differential ultracentrifugation from GBM cell culture supernatant. EVs were thoroughly characterized by transmission and cryo-electron microscopy, nanoparticle tracking analysis (NTA), and EV marker expression by Western blot and fluorescent NTA. EV uptake by macrophage cells was observed using confocal microscopy. The transfer of miR-25/93 as an EV cargo to macrophages was confirmed by miRNA real-time qPCR. The impact of miR-25/93 on the polarization of recipient macrophages was shown by transcriptional analysis, cytokine secretion and functional assays using co-cultured T cells. RESULTS: We show that indirect effects of hypoxia can have immunosuppressive consequences through an EV and microRNA dependent mechanism active in both murine and human tumor and immune cells. Hypoxia enhanced EV release from GBM cells and upregulated expression of miR-25/93 both in cells and in EV cargos. Hypoxic GBM-derived EVs were taken up by macrophages and the miR-25/93 cargo was transferred, leading to impaired cGAS-STING pathway activation revealed by reduced type I IFN expression and secretion by macrophages. The EV-treated macrophages downregulated expression of M1 polarization-associated genes Cxcl9, Cxcl10 and Il12b, and had reduced capacity to attract activated T cells and to reactivate them to release IFN-γ, key components of an efficacious anti-tumor immune response. CONCLUSIONS: Our findings suggest a mechanism by which immunosuppressive consequences of hypoxia mediated via miRNA-25/93 can be exported from hypoxic GBM cells to normoxic macrophages via EVs, thereby contributing to more widespread T-cell mediated immunosuppression in the tumor microenvironment.

Approaches of T Cell Activation and Differentiation for CAR-T Cell Therapies.

Chimeric antigen receptor (CAR) T cell therapies are ex vivo manufactured cellular products that have been useful in the treatment of blood cancers and solid tumors. The quality of the final cellular product is influenced by several amenable factors during the manufacturing process. This review discusses several of the influences on cell product phenotype, including the raw starting material, methods of activation and transduction, and culture supplementation.

Non-clinical immuno-toxicological evaluation of HER1 cancer vaccine in non-human primates: a 12-month study.

Human epidermal growth factor receptor (HER1) constitutes a tumor associated antigen. Its overexpression in many epithelial tumors has been associated with bad prognosis and poor survival. Cancer vaccine based on the extracellular domain (ECD) of HER1 and adjuvated in very small sized proteoliposomes (VSSP) and Montanide ISA 51-VG is a new and complementary approach for the treatment of epithelial tumors. The present study deals with the immunogenicity of this vaccine in Macaca fascicularis monkeys and evaluation of its toxicity during 12 months. Twelve monkeys were randomized into two groups of 3 animals per sex: control and vaccinated. Treated monkeys received 9 doses of vaccination and were daily inspected for clinical signs. Body weight, rectal temperature, cardiac and respiratory rates were measured during the study. Humoral immune response, clinical pathology parameters and delayed type hypensensitivity were analyzed. Skin biopsy was performed at the end of the study in all animals. Animal's survival in the study was 100% (n=12). Local reactions were observed at the administration site of four treated animals (n=6), with two showing slight inflammatory cutaneous damage. Clinical pathology parameters were not affected. HER1 vaccine induced high IgG antibodies titers in the treated animals even when DTH was not observed. The induced antibodies recognized HER1+ tumor cell lines, decreased HER1 phosphorylation and showed anti-proliferative and pro-apoptotic effects in H125 cells. In general the present study showed that HER1 vaccine induced specific immune response in M. fascicularis monkeys and was well tolerated, suggesting it could be safely used in clinical studies in epithelial cancer patients.