Project description:Immunotherapy has had a tremendous impact on cancer treatment in the past decade, with hitherto unseen responses at advanced and metastatic stages of the disease. However, the aggressive brain tumor glioblastoma (GBM) is highly immunosuppressive and remains largely refractory to current immunotherapeutic approaches. The cGAS-STING cytoplasmic double stranded DNA (dsDNA) sensing pathway has emerged as a next-generation immunotherapy target with potent local immune stimulatory properties. Here, we investigated the status of the STING pathway in GBM and the modulation of the brain tumor microenvironment (TME) with the STING agonist ADU-S100. Our data reveal the presence of STING in human GBM specimens, where it stains strongly in the tumor vasculature. We show that human GBM explants can respond to STING agonist treatment by secretion of inflammatory cytokines. In murine GBM models, we show a profound shift in the tumor immune landscape after STING agonist treatment, with massive infiltration of the tumor-bearing hemisphere with innate immune cells including inflammatory macrophages, neutrophils and NK populations. Treatment of established murine intracranial GL261 and CT-2A tumors by biodegradable ADU-S100-loaded intracranial implants demonstrated a significant increase in survival in both models and long-term survival with immune memory in GL261. Responses to treatment were abolished by NK cell depletion. This study reveals therapeutic potential and deep remodeling of the TME by STING activation in GBM and warrants the further examination of STING agonists alone or in combination with other immunotherapies such as cancer vaccines, CAR T cells, NK therapies or immune checkpoint blockade.
Project description:Cyclic dinucleotide (CDN) agonists of the STimulator of InterferoN Genes (STING) pathway have shown immune activation and tumor clearance in pre-clinical models. However, CDNs administered intratumorally also promote STING activation leading to direct cytotoxicity of many cell types in the tumor microenvironment (TME), systemic inflammation due to rapid tumor extravasation of the CDN, and immune ablation in the TME. These result in a failure to establish immunological memory. ExoSTING, an engineered extracellular vesicle (EV) exogenously loaded with CDN, enhances the potency of CDN and preferentially activates antigen presenting cells in the TME. Following intratumoral injection, exoSTING was retained within the tumor, enhanced local Th1 responses and recruitment of CD8+ T cells, and generated systemic anti-tumor immunity to the tumor. ExoSTING at therapeutically active doses did not induce systemic inflammatory cytokines, resulting in an enhanced therapeutic window. ExoSTING is a novel, differentiated therapeutic candidate that leverages the natural biology of EVs to enhance the activity of CDNs.
Project description:Unfolded protein response (UPR) is a central stress response pathway in normal cells that is hijacked by tumor cells for their survival. However, how activation of UPR in cancer cells shapes the tumor microenvironment (TME) remain largely unexplored. Here, we investigated the role of IRE1α-XBP1s on modulation of TME dynamics in prostate cancer (PCa).
Project description:The cancer-immunity cycle is regulated by a series of stimulatory and inhibitory factors. The Stimulator of Interferon Genes (STING) pathway, a key stimulator of type I interferon production, bridges innate and adaptive immunity to promote anti-tumor responses. Using a syngeneic pancreatic tumor model, we characterized the single-cell landscape changes induced by STING stimulation. Our findings revealed that STING agonist treatment reprograms transcription across multiple cell lineages, boosting innate immune responses and lymphocyte activation, thereby enhancing tumor killing. Single-cell transcriptome sequencing identified significant increases in monocytes, neutrophils, macrophages, and CD8 T cells, indicating augmented tumor inflammation. Differential gene expression analysis highlighted upregulated genes related to immune cell effector mechanisms and antigen presentation. Functional assays confirmed that STING activation enhances T cell-mediated tumor killing through myeloid cell activation. These results underscore the potential of STING agonists in reprogramming the tumor microenvironment to potentiate anti-tumor immunity, although clinical translation remains challenging due to pharmacokinetic limitations and potential systemic toxicity. Further research is needed to optimize STING agonist delivery and dosage for effective cancer immunotherapy.
Project description:Lipid metabolism plays an important role in tumor progression and immune evasion. Targeting fatty acid oxidation (FAO) has been shown to be a promising approach to treat cancers. However, the impact of FAO inhibition on tumor immune microenvironment is still less understood. In this study, we found that inhibiting FAO by targeting CPT1A dramatically triggers cGAS/STING activation through inducing cytoplasmic leakage of mitochondrial DNA. This leads to the infiltration of neutrophils into tumors and drive anti-tumor effects of a subset of neutrophils, which plays a crucial role in inhibiting tumor growth. Our current findings suggest that CPT1A could be a promising target for TNBC therapy and, moreover, we uncover an essential anti-tumor role of neutrophils upon cGAS/STING activation.
Project description:To elucidate the mechanisms that regulate metabolic suppression versus sustained metabolic fitness in NK cells in the tumor microenvironment (TME), we assessed global differences in protein levels via proteomics in NK cells exposed to the TME or control media.