Carboplatin activates the cGAS-STING pathway by upregulating the TREX-1 (three prime repair exonuclease 1) expression in human melanoma

The crosstalk between oncogenic signaling and ferroptosis in cancer

Ferroptosis, a novel form of cell death regulation, was identified in 2012. It is characterized by unique features that differentiate it from other types of cell death, including necrosis, apoptosis, autophagy, and pyroptosis. Ferroptosis is defined by an abundance of iron ions and lipid peroxidation, resulting in alterations in subcellular structures, an elevation in reactive oxygen species (ROS), a reduction in glutathione (GSH) levels, and an augmentation in Fe (II) cytokines. Ferroptosis, a regulated process, is controlled by an intricate network of signaling pathways, where multiple stimuli can either enhance or hinder the process. This review primarily examines the defensive mechanisms of ferroptosis and its interaction with the tumor microenvironment. The analysis focuses on the pathways that involve AMPK, p53, NF2, mTOR, System Xc-, Wnt, Hippo, Nrf2, and cGAS-STING. The text discusses the possibilities of employing a combination therapy that targets several pathways for the treatment of cancer. It emphasizes the necessity for additional study in this field.

Sudocetaxel Zendusortide (TH1902) triggers the cGAS/STING pathway and potentiates anti-PD-L1 immune-mediated tumor cell killing

The anticancer efficacy of Sudocetaxel Zendusortide (TH1902), a peptide-drug conjugate internalized through a sortilin-mediated process, was assessed in a triple-negative breast cancer-derived MDA-MB-231 immunocompromised xenograft tumor model where complete tumor regression was observed for more than 40 days after the last treatment. Surprisingly, immunohistochemistry analysis revealed high staining of STING, a master regulator in the cancer-immunity cycle. A weekly administration of TH1902 as a single agent in a murine B16-F10 melanoma syngeneic tumor model demonstrated superior tumor growth inhibition than did docetaxel. A net increase in CD45 leukocyte infiltration within TH1902-treated tumors, especially for tumor-infiltrating lymphocytes and tumor-associated macrophages was observed. Increased staining of perforin, granzyme B, and caspase-3 was suggestive of elevated cytotoxic T and natural killer cell activities. Combined TH1902/anti-PD-L1 treatment led to increases in tumor growth inhibition and median animal survival. TH1902 inhibited cell proliferation and triggered apoptosis and senescence in B16-F10 cells in vitro, while inducing several downstream effectors of the cGAS/STING pathway and the expression of MHC-I and PD-L1. This is the first evidence that TH1902 exerts its antitumor activity, in part, through modulation of the immune tumor microenvironment and that the combination of TH1902 with checkpoint inhibitors (anti-PD-L1) could lead to improved clinical outcomes.

Carboplatin ameliorates the pathogenesis of experimental autoimmune encephalomyelitis by inducing T cell apoptosis

Apoptosis is a natural physiological process that can maintain the homeostasis of the body and immune system. This process plays an important role in the system's resistance to autoimmune development. Because of the dysfunction of cell apoptosis mechanism, the number of autoreactive cells in the peripheral tissue increases along with their accumulation. This will lead to the development of autoimmune diseases, such as multiple sclerosis (MS). MS is an immune-mediated disease of the central nervous system characterized by severe white matter demyelination. Because of the complexity of its pathogenesis, there is no drug to cure it completely. Experimental autoimmune encephalomyelitis (EAE) is an ideal animal model for the study of MS. Carboplatin (CA) is a second-generation platinum anti-tumor drug. In this study, we attempted to assess whether CA could be used to ameliorate EAE. CA reduced spinal cord inflammation, demyelination, and disease scores in mice with EAE. Moreover, the number and proportion of pathogenic T cells especially Th1 and Th17 in the spleen and draining lymph nodes were reduced in CA-treated EAE mice. Proteomic differential enrichment analysis showed that the proteins related to apoptosis signal changed significantly after CA treatment. CFSE experiment showed that CA significantly inhibited the T cell proliferation. Finally, CA also induced apoptosis in activated T cells and MOG-specific T cells in vitro. Overall, our findings indicated that CA plays a protective role in the initiation and progression of EAE and has the potential to be a novel drug in the treatment of MS.

The Crucial Roles and Research Advances of cGAS-STING Pathway in Cutaneous Disorders

The cGAS-STING signaling pathway senses the presence of cytosolic DNA, induces strong type I interferon responses, and enhances inflammatory cytokine production, placing it as an important axis in infection, autoimmunity, and tumor immunity. Recent studies have shown that the abnormalities and/or dysfunctions of cGAS-STING signaling are closely related to the pathogenesis of skin diseases and/or cancers. Additionally, a variety of new therapeutics targeting the cGAS-STING signaling are in development for the treatment of skin disorders. However, the precise molecular mechanisms of cGAS-STING-mediated cutaneous disorders have not been fully elucidated. In this review, we will summarize the regulatory roles and mechanisms of cGAS-STING signaling in skin disorders and recent progresses of cGAS-STING-related drugs as well as their potential clinical applications.

TREX1 cytosolic DNA degradation correlates with autoimmune disease and cancer immunity

The N-terminal domain of Three Prime Repair Exonuclease 1 (TREX1) is catalytically active and can degrade dsDNA or ssDNA in the cytosol, whereas the C-terminal domain is primarily involved in protein localization. TREX1 deficiency induces cytosolic DNA accumulation as well as activation of the cGAS-STING-IFN signaling pathway, which results in tissue inflammation and autoimmune diseases. Furthermore, TREX1 expression in cancer immunity can be adaptively regulated to promote tumor proliferation, making it a promising therapeutic target.

How the Innate Immune DNA Sensing cGAS-STING Pathway Is Involved in Apoptosis

The cGAS-STING signaling axis can be activated by cytosolic DNA, including both non-self DNA and self DNA. This axis is used by the innate immune system to monitor invading pathogens and/or damage. Increasing evidence has suggested that the cGAS-STING pathway not only facilitates inflammatory responses and the production of type I interferons (IFN), but also activates other cellular processes, such as apoptosis. Recently, many studies have focused on analyzing the mechanisms of apoptosis induced by the cGAS-STING pathway and their consequences. This review gives a detailed account of the interplay between the cGAS-STING pathway and apoptosis. The cGAS-STING pathway can induce apoptosis through ER stress, NLRP3, NF-κB, IRF3, and IFN signals. Conversely, apoptosis can feed back to regulate the cGAS-STING pathway, suppressing it via the activation of caspases or promoting it via mitochondrial DNA (mtDNA) release. Apoptosis mediated by the cGAS-STING pathway plays crucial roles in balancing innate immune responses, resisting infections, and limiting tumor growth.

The Role of cGAS-STING in Age-Related Diseases from Mechanisms to Therapies

With aging, the incidence of age-related diseases increases. Hence, age-related diseases are inevitable. However, the mechanisms by which aging leads to the onset and progression of age-related diseases remain unclear. It has been reported that inflammation is closely associated with age-related diseases and that the cGAS-STING signaling pathway, which can sense the aberrant presence of cytosolic DNA during aging and induce an inflammatory response, is an important mediator of inflammation in age-related diseases. With a better understanding of the structure and molecular biology of the cGAS-STING signaling axis, numerous selective inhibitors and agonists targeting the cGAS-STING pathway in human age-related diseases have been developed to modulate inflammatory responses. Here, we provide a narrative review of the activity of the cGAS- STING pathway in age-related diseases and discuss its general mechanisms in the onset and progression of age-related diseases. In addition, we outline treatments targeting the cGAS-STING pathway, which may constitute a potential therapeutic alternative for age-related diseases.

Exonucleases: Degrading DNA to Deal with Genome Damage, Cell Death, Inflammation and Cancer

Although DNA degradation might seem an unwanted event, it is essential in many cellular processes that are key to maintaining genomic stability and cell and organism homeostasis. The capacity to cut out nucleotides one at a time from the end of a DNA chain is present in enzymes called exonucleases. Exonuclease activity might come from enzymes with multiple other functions or specialized enzymes only dedicated to this function. Exonucleases are involved in central pathways of cell biology such as DNA replication, repair, and death, as well as tuning the immune response. Of note, malfunctioning of these enzymes is associated with immune disorders and cancer. In this review, we will dissect the impact of DNA degradation on the DNA damage response and its links with inflammation and cancer.