RESUMEN
cGAS-STING signaling is a significant component of the innate immune system and functions as a vital sentinel mechanism to monitor cellular and tissue aberrations in microbial invasion and organ injury. cGAS, a cytosolic DNA sensor, is specialized in recognizing abnormally localized cytoplasmic double-stranded DNA (dsDNA) and catalytically synthesizes the second messenger cyclic-GMP-AMP (cGAMP), which initiates a cascade of type I interferon and inflammatory responses mediated by STING. Micronucleus, a byproduct of chromosomal missegregation during anaphase, are also significant contributors to cytoplasmic dsDNA. These unstable subcellular structures are susceptible to irreversible nuclear envelope rupture, exposing genomic dsDNA to the cytoplasm, which potently recruits cGAS and activates STING-mediated innate immune signaling and its downstream activities, including type I interferon and classical nuclear factor-κB (NF-κB) signaling pathways lead to senescence, apoptosis, autophagy activating anti-cancer immunity or directly killing tumor cells. However, sustained STING activation-induced endoplasmic reticulum stress, activated chronic type I interferon and nonclassical NF-κB signaling pathways remodel immunosuppressive tumor microenvironment, leading to immune evasion and facilitating tumor metastasis. Therefore, activated cGAS-STING signaling plays a dual role of suppressing or facilitating tumor growth in tumorigenesis and therapy. This review elaborates on research advances in mechanisms of micronucleus inducing activation of cGAS-STING signaling and its implications in tumorigenesis and therapeutic strategies of malignant tumors.
RESUMEN
Tumor cells adaptively reforge their metabolism to meet the demands of energy and biosynthesis. Mitochondria, pivotal organelles in the metabolic reprogramming of tumor cells, contribute to tumorigenesis and cancer progression significantly through various dysfunctions in both tumor and immune cells. Alterations in mitochondrial dynamics and metabolic signaling pathways exert crucial regulatory influence on the activation, proliferation, and differentiation of immune cells. The tumor microenvironment orchestrates the activation and functionality of tumor-infiltrating immune cells by reprogramming mitochondrial metabolism and inducing shifts in mitochondrial dynamics, thereby facilitating the establishment of a tumor immunosuppressive microenvironment. Stress-induced leakage of mitochondrial DNA contributes multifaceted regulatory effects on anti-tumor immune responses and the immunosuppressive microenvironment by activating multiple natural immune signals, including cGAS-STING, TLR9, and NLRP3. Moreover, mitochondrial DNA-mediated immunogenic cell death emerges as a promising avenue for anti-tumor immunotherapy. Additionally, mtROS, a crucial factor in tumorigenesis, drives the formation of tumor immunosuppressive microenvironment by changing the composition of immune cells within the tumor microenvironment. This review focuses on the intrinsic relationship between mitochondrial biology and anti-tumor immune responses from multiple angles. We expect to explore the core role of mitochondria in the dynamic interplay between the tumor and the host, in order to facilitate the development of targeted mitochondrial strategies for anti-tumor immunotherapy.
RESUMEN
Targeting cGAS-STING pathway is a promising strategy in tumor treatment. The pattern recognition receptor cGAS identifies dsDNA and catalyzes the formation of the second messenger 2'3'-cGAMP, activating the downstream interferons and pro-inflammatory cytokines through the adaptor protein STING. Notably, in tumor immune microenvironment, key components of cGAS-STING pathway are transferred among neighboring cells. The intercellular transmission under these contexts serves to sustain and amplify innate immune responses while facilitating the emergence of adaptive immunity. The membrane-based system, including extracellular vesicles transport, phagocytosis and membrane fusion transmit dsDNA, cGAMP and activated STING, enhancing the immune surveillance and inflammatory. The membrane proteins, including specific protein channel and intercellular gap junctions, transfer cGAMP and dsDNA, which are crucial to regulate immune responses. And the ligand-receptor interactions for interferons transmission amplifies the anti-tumor response. This review elaborates on the regulatory mechanisms of cell-to-cell communications of cGAS-STING pathway in tumor immune microenvironment. We further explore how these mechanisms modulate immunological processes and discuss potential interventions and immunotherapeutic strategies targeting these signaling cascades.