Chromosomal instability drives metastasis through a cytosolic DNA response

Bendamustine-rituximab elicits dual tumoricidal and immunomodulatory responses via cGAS-STING activation in diffuse large B-cell lymphoma

BACKGROUND

Bendamustine-rituximab (BR) therapy stands out as a promising alternative for elderly patients with diffuse large B-cell lymphoma (DLBCL), demonstrating notable efficacy when conventional regimens pose challenges. Despite its clinical success, the intricate mechanisms underlying BR therapy have remained elusive.

METHODS

DLBCL cell lines were used to investigate the mechanism of BR therapy in vitro. RNA-seq and Western blot were used to explore the target pathways of BR therapy. STING was knocked out using Crispr-cas9 and inhibited using H-151 to investigate its role in BR therapy. Bulk RNA-seq and single-cell RNA-seq data from patients were analyzed to investigate the association between STING and pyroptosis pathways, validated using STING downregulated cells. Flow cytometry, transwell experiments and co-culture experiments were performed to investigate the inflammatory phenotype of DLBCL cells after BR treatment and its effect on T-cell recruitment and activation.

RESULTS

This study elucidates that BR elicits direct tumoricidal effects by promoting apoptosis and inducing cell cycle arrest. The synergistic impact with rituximab is further potentiated by complement addition, demonstrating the pivotal role of in vivo antibody-dependent cellular cytotoxicity. Moreover, our investigation reveals that, through a cGAS-STING-dependent pathway, prolonged exposure to BR induces pyroptosis in DLBCL cells. Activation of the cGAS-STING pathway by BR therapy triggers the release of inflammatory factors and upregulates major histocompatibility complex molecules, shaping an immunologically hot tumor microenvironment.

CONCLUSIONS

This unique dual influence not only directly targets DLBCL cells but also engages the patient's immune system, paving the way for innovative combination therapies. The study provides comprehensive insights into the multifaceted actions of BR in DLBCL, offering a foundation for refined and personalized treatment strategies in elderly patients.

High chromosomal instability is associated with higher 10-year risks of recurrence for hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer patients: clinical evidence from a large-scale, multiple-site, retrospective study

Long-term survival varies among hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-) breast cancer patients and is seriously impaired by metastasis. Chromosomal instability (CIN) was one of the key drivers of breast cancer metastasis. Here we evaluate CIN and 10-year invasive disease-free survival (iDFS) and overall survival (OS) in HR+/HER2-- breast cancer. In this large-scale, multiple-site, retrospective study, 354 HR+/HER2- breast cancer patients were recruited. Of these, 204 patients were used for internal training, 70 for external validation, and 80 for cross-validation. All medical records were carefully reviewed to obtain the disease recurrence information. Formalin-fixed paraffin-embedded tissue samples were collected, followed by low-pass whole-genome sequencing with a median genome coverage of 1.86X using minimal 1 ng DNA input. CIN was then assessed using a customized bioinformatics workflow. Three or more instances of CIN per sample was defined as high CIN and the frequency was 42.2% (86/204) in the internal cohort. High CIN correlated significantly with increased lymph node metastasis, vascular invasion, progesterone receptor negative status, HER2 low, worse pathological type, and performed as an independent prognostic factor for HR+/- breast cancer. Patients with high CIN had shorter iDFS and OS than those with low CIN [10-year iDFS 11.1% versus 82.2%, hazard ratio (HR) = 11.12, p < 0.01; 10-year OS 45.7% versus 94.3%, HR = 14.17, p < 0.01]. These findings were validated in two external cohorts with 70 breast cancer patients. Moreover, high CIN could predict the prognosis more accurately than Adjuvant! Online score (10-year iDFS 11.1% versus 48.6%, HR = 2.71, p < 0.01). Cross-validation analysis found that high consistency (83.8%) was observed between CIN and MammaPrint score, while only 45% between CIN and Adjuvant! Online score. In conclusion, high CIN is an independent prognostic indicator for HR+/HER2- breast cancer with shorter iDFS and OS and holds promise for predicting recurrence and metastasis.

Chromosome instability functions as a potential therapeutic reference by enhancing chemosensitivity to BCL-XL inhibitors in colorectal carcinoma

Chromosome instability (CIN) and subsequent aneuploidy are prevalent in various human malignancies, influencing tumor progression such as metastases and relapses. Extensive studies demonstrate the development of chemoresistance in high-CIN tumors, which poses significant therapeutic challenges. Given the association of CIN with poorer prognosis and suppressed immune microenvironment observed in colorectal carcinoma (CRC), here we aimed to discover chemotherapeutic drugs exhibiting increased inhibition against high-CIN CRC cells. By using machine learning methods, we screened out two BCL-XL inhibitors Navitoclax and WEHI-539 as CIN-sensitive reagents in CRC. Subsequent analyses using a CIN-aneuploidy cell model confirmed the vulnerability of high-CIN CRC cells to these drugs. We further revealed the critical role of BCL-XL in the viability of high-CIN CRC cells. In addition, to ease the evaluation of CIN levels in clinic, we developed a three-gene signature as a CIN surrogate to predict prognosis, chemotherapeutic and immune responses in CRC samples. Our results demonstrate the potential value of CIN as a therapeutic target in CRC treatment and the importance of BCL-XL in regulating survival of high-CIN CRC cells, therefore representing a valuable attempt to translate a common trait of heterogeneous tumor cells into an effective therapeutic target.

An overview of the functions and mechanisms of APOBEC3A in tumorigenesis

The APOBEC3 (A3) family plays a pivotal role in the immune system by performing DNA/RNA single-strand deamination. Cancers mostly arise from the accumulation of chronic mutations in somatic cells, and recent research has highlighted the A3 family as a major contributor to tumor-associated mutations, with A3A being a key driver gene leading to cancer-related mutations. A3A helps to defend the host against virus-induced tumors by editing the genome of cancer-associated viruses that invade the host. However, when it is abnormally expressed, it leads to persistent, chronic mutations in the genome, thereby fueling tumorigenesis. Notably, A3A is prominently expressed in innate immune cells, particularly macrophages, thereby affecting the functional state of tumor-infiltrating immune cells and tumor growth. Furthermore, the expression of A3A in tumor cells may directly affect their proliferation and migration. A growing body of research has unveiled that A3A is closely related to various cancers, which signifies the potential significance of A3A in cancer therapy. This paper mainly classifies and summarizes the evidence of the relationship between A3A and tumorigenesis based on the potential mechanisms, aiming to provide valuable references for further research on the functions of A3A and its development in the area of cancer therapy.

TBK1-Zyxin signaling controls tumor-associated macrophage recruitment to mitigate antitumor immunity

Mechanical control is fundamental for cellular localization within a tissue, including for tumor-associated macrophages (TAMs). While the innate immune sensing pathways cGAS-STING and RLR-MAVS impact the pathogenesis and therapeutics of malignant diseases, their effects on cell residency and motility remain incompletely understood. Here, we uncovered that TBK1 kinase, activated by cGAS-STING or RLR-MAVS signaling in macrophages, directly phosphorylates and mobilizes Zyxin, a key regulator of actin dynamics. Under pathological conditions and in STING or MAVS signalosomes, TBK1-mediated Zyxin phosphorylation at S143 facilitates rapid recruitment of phospho-Zyxin to focal adhesions, leading to subsequent F-actin reorganization and reduced macrophage migration. Intratumoral STING-TBK1-Zyxin signaling was evident in TAMs and critical in antitumor immunity. Furthermore, myeloid-specific or global disruption of this signaling decreased the population of CD11b+ F4/80+ TAMs and promoted PD-1-mediated antitumor immunotherapy. Thus, our findings identify a new biological function of innate immune sensing pathways by regulating macrophage tissue localization, thus providing insights into context-dependent mitigation of antitumor immunity.

cGAS/STING signalling pathway in senescence and oncogenesis

The cGAS/STING signaling pathway is a crucial component of the innate immune system, playing significant roles in sensing cytosolic DNA, regulating cellular senescence, and contributing to oncogenesis. Recent advances have shed new lights into the molecular mechanisms governing pathway activation in multiple pathophysiological settings, the indispensable roles of cGAS/STING signaling in cellular senescence, and its context-dependent roles in cancer development and suppression. This review summarizes current knowledge related to the biology of cGAS/STING signaling pathway and its participations into senescence and oncogenesis. We further explore the clinical implications and therapeutic potential for cGAS/STING targeted therapies, and faced challenges in the field. With a focus on molecular mechanisms and emerging pharmacological targets, this review underscores the importance of future studies to harness the therapeutic potential of the cGAS/STING pathway in treating senescence-related disorders and cancer. Advanced understanding of the regulatory mechanisms of cGAS/STING signaling, along with the associated deregulations in diseases, combined with the development of new classes of cGAS/STING modulators, hold great promises for creating novel and effective therapeutic strategies. These advancements could address current treatment challenges and unlock the full potential of cGAS/STING in treating senescence-related disorders and oncogenesis.

The cGAS-STING mediated crosstalk between innate immunity and autophagy in leishmaniasis using mathematical modeling: Uncovering new therapeutic avenues

The present paper deals with the investigation into the cGAS-STING pathway, focusing on the signaling of interferons through mathematical modeling and identifying a significant positive feedback loop regulated by STING for activation of type 1 interferons (IFN-1). Cyclic GMP-AMP synthase (cGAS) is responsible for detecting cytosolic DNA and initiating the STING (stimulator of interferon genes) pathway, which in turn causes the synthesis of pro-inflammatory cytokines and type I interferons. In addition to being crucial for pathogen identification, this route interacts with autophagy, a cellular mechanism that is necessary for immunological homeostasis and pathogen removal. In the context of Leishmania infection, the cGAS-STING signaling axis has come to light as a critical mediator of the crosstalk between innate immunity and autophagy. Further, the protein-protein interaction studies underscored the significance of two distinct domains in mediating interactions with IRF3 and LC3. Importantly, our findings suggest the possibility of manipulating STING concomitantly to regulate IRF3 and LC3 independently. This study remarkably advances our understanding of STING's multifaceted roles, particularly in regulating IFN-1 and autophagy, highlighting its pivotal role as a cross-talk point in leishmaniasis.

TMEM173 is a biomarker of predicting prognosis, immune responses and therapeutic effect in human lung adenocarcinoma

The concerns on the function of Transmembrane protein 173 (TMEM173)-dependent innate immunity in prevention and management of cancers has recently been increased. The role of TMEM173 in predicting the prognosis and response to treatment in lung adenocarcinoma (LUAD) remain unclear. Our study revealed that TMEM173 expression was significantly differential in various tumors and the related prognosis was heterogeneous. Further investigation discovered that the expression level of TMEM173 in LUAD tissues was significantly decreased and high TMEM173 expression is associated with better overall survival in LUAD patients. TMEM173 was mainly enriched in immune response-regulating signaling pathway, T cell activation and cell cycle G2/M phase. Furthermore, it was found that TMEM173 expression was positively related to markers and infiltration levels of tumor-infiltrating immune cells. TMEM173 could predict response to targeted therapy, chemotherapy and immunotherapy in LUAD patients. In vitro TMEM173 knockdown decreased the percentage of G2 phase cells, contributing to the increased growth of lung cancer cells. These results implied that TMEM173 might be a prognostic biomarker and a potential target of precision therapy for LUAD patients.

Circulating Neoplastic-Immune Hybrid Cells Are Biomarkers of Occult Metastasis and Treatment Response in Pancreatic Cancer

BACKGROUND/OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) presents significant diagnostic and prognostic challenges, as current biomarkers frequently fail to accurately stage disease, predict rapid metastatic recurrence (rPDAC), or assess response to neoadjuvant therapy (NAT). We investigated the potential for circulating neoplastic-immune hybrid cells (CHCs) as a non-invasive, multifunctional biomarker for PDAC.

METHODS

Peripheral blood specimens were obtained from patients diagnosed with PDAC. CHCs were detected by co-expression of pan-cytokeratin and CD45, normalized to 50,000 peripheral blood mononuclear cells. rPDAC was defined as metastatic recurrence within six months of margin-negative pancreatectomy. Cyclic immunofluorescence (CyCIF) analyses compared hybrid phenotypes in blood and tumors.

RESULTS

Blood samples were collected from 42 patients with PDAC prior to resection. Those with radiographically occult metastatic disease and rPDAC had higher preoperative CHC numbers compared to patients who did not (65.0 and 74.4, vs. 11.52 CHCs; p < 0.001). Patients with complete or near-complete pathologic responses to NAT had lower preoperative CHC numbers than partial and/or non-responders (1.7 vs. 13.1 CHCs; p = 0.008). When assessed longitudinally, those with partial pathologic response saw CHC levels become undetectable while on treatment but increase in the interval between NAT completion and resection. In contrast, patients with poor responses or development of metastatic disease experienced persistent CHC detection during therapy or rising levels prior to radiographic evidence of metastases. Further, in metastatic PDAC patients, treatment-induced phenotypic changes in hybrid cells mirrored those in paired metastatic tumor samples.

CONCLUSIONS

CHC enumeration and phenotyping display promise as a real-time indicator of disease burden, recurrence risk, and treatment response in PDAC. CHCs have great potential as tumor-derived biomarkers to optimize therapeutic strategies and improve survival in patients with PDAC.

WRAD core perturbation impairs DNA replication fidelity promoting immunoediting in pancreatic cancer

It is unclear how cells counteract the potentially harmful effects of uncoordinated DNA replication in the context of oncogenic stress. Here, we identify the WRAD (WDR5/RBBP5/ASH2L/DPY30) core as a modulator of DNA replication in pancreatic ductal adenocarcinoma (PDAC) models. Molecular analyses demonstrated that the WRAD core interacts with the replisome complex, with disruption of DPY30 resulting in DNA re-replication, DNA damage, and chromosomal instability (CIN) without affecting cancer cell proliferation. Consequently, in immunocompetent models, DPY30 loss induced T cell infiltration and immune-mediated clearance of highly proliferating cancer cells with complex karyotypes, thus improving anti-tumor efficacy upon anti-PD-1 treatment. In PDAC patients, DPY30 expression was associated with high tumor grade, worse prognosis, and limited response to immune checkpoint blockade. Together, our findings indicate that the WRAD core sustains genome stability and suggest that low intratumor DPY30 levels may identify PDAC patients who will benefit from immune checkpoint inhibitors.

High prevalence of chromosome 17 in breast cancer micronuclei: a means to get rid of tumor suppressors?

Micronuclei (MN), defined as small extra-nuclear chromatin bodies enclosed by a nuclear envelope, serve as noticeable markers of chromosomal instability (CIN). The MN have been used for breast cancer (BC) screening, diagnosis, and prognosis. However, more recently they have gained attention as seats for active chromosomal rearrangements. BC subtypes exhibit differential CIN levels and aggressiveness. This study aimed to investigate MN chromosomal contents across BC subtypes, exploring its potential role in aggressiveness and pathogenesis. Immunostaining of BC cells was performed with anti-centromeric antibody followed by confocal microscopy. Further, fluorescence in situ hybridization (FISH) was done to check the presence of specific chromosomes in the MN. The real time PCR was also done from the RNA isolated from MN to check the expression of TP53 gene. BC cell lines (CLs) showed the presence of both centromere-positive ( +) and -negative ( -) MN, with significant variation in frequency among hormone and human epidermal growth factor receptor positive and triple-negative (TN) BC cells. FISH targeting chromosomes 1, 3, 8, 11, and 17 detected centromeric signals for all the above chromosomes in MN with a relatively higher prevalence of chromosome 17 in all the CLs. Out of all the CLs, TNBC cells demonstrated the highest frequency of centromere + and chromosome 17 + MN. TP53 expression could also be demonstrated inside the MN by FISH and real time PCR. Patient sample imprints also confirmed the presence of chromosome 17 in MN with polysomy of the same in corresponding nuclei. The high prevalence of chromosome 17 in BC MN may connote the importance of its rearrangements in the pathogenesis of BC. Further, the higher prevalence of chromosome 17 and 1 signals in TNBC MN point towards the significance of pathogenetic events involving the genes located in these chromosomes in evolution of this more aggressive phenotype.

The Role of STING-Mediated Activation of Dendritic Cells in Cancer Immunotherapy

The signaling pathway that comprises cyclic guanosine monophosphate-adenosine monophosphate (cGAMP or GMP-AMP) synthase (cGAS) and Stimulator of Interferon Genes (STING) is emerging as a druggable target for immunotherapy, with tumor-resident dendritic cells (DC) playing a critical role in mediating its effects. The STING receptor is part of the DNA-sensing cellular machinery, that can trigger the secretion of pro-inflammatory mediators, priming effector T cells and initiating specific antitumor responses. Yet, recent studies have highlighted the dual role of STING activation in the context of cancer: STING can either promote antitumor responses or enhance tumor progression. This dichotomy often depends on the cell type in which cGAS-STING signaling is induced and the activation mode, namely acute versus chronic. Of note, STING activation at the DC level appears to be particularly important for tumor eradication. This review outlines the contribution of the different conventional and plasmacytoid DC subsets and describes the mechanisms underlying STING-mediated activation of DCs in cancer. We further highlight how the STING pathway plays an intricate role in modulating the function of DCs embedded in tumor tissue. Additionally, we discuss the strategies being employed to harness STING activation for cancer treatment, such as the development of synthetic agonists and nano-based delivery systems, spotlighting the current techniques used to prompt STING engagement specifically in DCs.

Multi-stage mechanisms of tumor metastasis and therapeutic strategies

The cascade of metastasis in tumor cells, exhibiting organ-specific tendencies, may occur at numerous phases of the disease and progress under intense evolutionary pressures. Organ-specific metastasis relies on the formation of pre-metastatic niche (PMN), with diverse cell types and complex cell interactions contributing to this concept, adding a new dimension to the traditional metastasis cascade. Prior to metastatic dissemination, as orchestrators of PMN formation, primary tumor-derived extracellular vesicles prepare a fertile microenvironment for the settlement and colonization of circulating tumor cells at distant secondary sites, significantly impacting cancer progression and outcomes. Obviously, solely intervening in cancer metastatic sites passively after macrometastasis is often insufficient. Early prediction of metastasis and holistic, macro-level control represent the future directions in cancer therapy. This review emphasizes the dynamic and intricate systematic alterations that occur as cancer progresses, illustrates the immunological landscape of organ-specific PMN creation, and deepens understanding of treatment modalities pertinent to metastasis, thereby identifying some prognostic and predictive biomarkers favorable to early predict the occurrence of metastasis and design appropriate treatment combinations.

Genomic instability as a driver and suppressor of anti-tumor immunity

Genomic instability is a driver and accelerator of tumorigenesis and influences disease outcomes across cancer types. Although genomic instability has been associated with immune evasion and worsened disease prognosis, emerging evidence shows that genomic instability instigates pro-inflammatory signaling and enhances the immunogenicity of tumor cells, making them more susceptible to immune recognition. While this paradoxical role of genomic instability in cancer is complex and likely context-dependent, understanding it is essential for improving the success rates of cancer immunotherapy. In this review, we provide an overview of the underlying mechanisms that link genomic instability to pro-inflammatory signaling and increased immune surveillance in the context of cancer, as well as discuss how genomically unstable tumors evade the immune system. A better understanding of the molecular crosstalk between genomic instability, inflammatory signaling, and immune surveillance could guide the exploitation of immunotherapeutic vulnerabilities in cancer.

Targeting STING signaling for the optimal cancer immunotherapy

Despite the transformative impact of anti-PD-1/PD-L1 therapies, challenges such as low response rates persist. The stimulator of interferon genes (STING) pathway, a crucial element of innate immunity, emerges as a strategic target to overcome these limitations. Understanding its multifaceted functions in cancer, including antigen presentation and response to DNA damage, provides valuable insights. STING agonists, categorized into cyclic dinucleotides (CDNs) and non-CDNs, exhibit promising safety and efficacy profiles. Innovative delivery systems, including antibody-drug conjugates, nanocarriers, and exosome-based therapies, address challenges associated with systemic administration and enhance targeted tumor delivery. Personalized vaccines, such as DT-Exo-STING, showcase the adaptability of STING agonists for individualized treatment. These advancements not only offer new prospects for combination therapies but also pave the way for overcoming resistance mechanisms. This review focuses on the potential of targeting STING pathway to enhance cancer immunotherapy. The integration of STING agonists into cancer immunotherapy holds promise for more effective, personalized, and successful approaches against malignancies, presenting a beacon of hope for the future of cancer treatment.

The value of chromosome instability detected by low-pass whole-genome sequencing in preoperative prediction of sentinel lymph node metastasis in breast cancer

Background

Breast cancer is a malignancy characterized by chromosomal instability (CIN). This study aimed to examine the potential diagnostic value of chromosomal instability, detected by low-pass whole-genome sequencing (LPWGS), in the preoperative evaluation of sentinel lymph node metastasis (SLNM) in breast cancer.

Methods

A retrospective investigation of clinical records from 29 patients with breast cancer revealed two distinct groups based on sentinel lymph node biopsy (SLNB) results: the SLN metastasis group (24 cases) and the SLN non-metastasis group (five cases). CIN and CIN scores were evaluated using LPWGS. An analysis of univariate data and binary logistic regression was employed to identify factors influencing SLNM, and a curve with receiver operating characteristics (ROC) was constructed to assess the diagnostic utility of CIN in predicting SLNM.

Results

A significant association between the SLNM and CIN high groups was observed in breast cancer (P=0.011). The CIN score in the metastasis group (17,665.055 ± 8,630.691) was higher than that in the non-metastasis group (9,247.973 ± 3,692.873), demonstrating a significant difference (P=0.044). Univariate binary logistic regression analysis indicated that CIN was a significant predictor for SLNM (odds ratio: 4.036, 95% CI: 1.015-16.047, P=0.048). The AUC of CIN for preoperative diagnosis of SLNM was 0.808 (95%CI: 0.635-0.982, P=0.033), with a sensitivity value of 67.0% and specificity of 100.0% at a threshold of 13,563.

Conclusion

Detecting CIN through LPWGS demonstrates diagnostic potential in predicting SLNM in patients with breast cancer before surgery. This approach offers a novel method for assessing axillary lymph node status in clinical practice.

TEX264 drives selective autophagy of DNA lesions to promote DNA repair and cell survival

DNA repair and autophagy are distinct biological processes vital for cell survival. Although autophagy helps maintain genome stability, there is no evidence of its direct role in the repair of DNA lesions. We discovered that lysosomes process topoisomerase 1 cleavage complexes (TOP1cc) DNA lesions in vertebrates. Selective degradation of TOP1cc by autophagy directs DNA damage repair and cell survival at clinically relevant doses of topoisomerase 1 inhibitors. TOP1cc are exported from the nucleus to lysosomes through a transient alteration of the nuclear envelope and independent of the proteasome. Mechanistically, the autophagy receptor TEX264 acts as a TOP1cc sensor at DNA replication forks, triggering TOP1cc processing by the p97 ATPase and mediating the delivery of TOP1cc to lysosomes in an MRE11-nuclease- and ATR-kinase-dependent manner. We found an evolutionarily conserved role for selective autophagy in DNA repair that enables cell survival, protects genome stability, and is clinically relevant for colorectal cancer patients.

Clinical applications of STING agonists in cancer immunotherapy: current progress and future prospects

The STING (Stimulator of Interferon Genes) pathway is pivotal in activating innate immunity, making it a promising target for cancer immunotherapy. STING agonists have shown potential in enhancing immune responses, particularly in tumors resistant to traditional therapies. This scholarly review examines the diverse categories of STING agonists, encompassing CDN analogues, non-CDN chemotypes, CDN-infused exosomes, engineered bacterial vectors, and hybrid structures of small molecules-nucleic acids. We highlight their mechanisms, clinical trial progress, and therapeutic outcomes. While these agents offer significant promise, challenges such as toxicity, tumor heterogeneity, and delivery methods remain obstacles to their broader clinical use. Ongoing research and innovation are essential to overcoming these hurdles. STING agonists could play a transformative role in cancer treatment, particularly for patients with hard-to-treat malignancies, by harnessing the body's immune system to target and eliminate cancer cells.

ER: a critical hub for STING signaling regulation

The Stimulator of Interferon Genes (STING) has a crucial role in mediating the immune response against cytosolic double-stranded DNA (dsDNA) and its activation is critically involved in various diseases. STING is synthesized, modified, and resides in the endoplasmic reticulum (ER), and its ER exit is intimately connected with its signaling. The ER, primarily known for its roles in protein folding, lipid synthesis, and calcium storage, has been identified as a pivotal platform for the regulation of a wide range of STING functions. In this review, we discuss the emerging factors that regulate STING in the ER and examine the interplay between STING signaling and ER pathways, highlighting the impacts of such regulations on immune responses and their potential implications in STING-related disorders.

Coordinated in confined migration: crosstalk between the nucleus and ion channel-mediated mechanosensation

Cell surface and intracellular mechanosensors enable cells to perceive different geometric, topographical, and physical cues. Mechanosensitive ion channels (MICs) localized at the cell surface and on the nuclear envelope (NE) are among the first to sense and transduce these signals. Beyond compartmentalizing the genome of the cell and its transcription, the nucleus also serves as a mechanical gauge of different physical and topographical features of the tissue microenvironment. In this review, we delve into the intricate mechanisms by which the nucleus and different ion channels regulate cell migration in confinement. We review evidence suggesting an interplay between macromolecular nuclear-cytoplasmic transport (NCT) and ionic transport across the cell membrane during confined migration. We also discuss the roles of the nucleus and ion channel-mediated mechanosensation, whether acting independently or in tandem, in orchestrating migratory mechanoresponses. Understanding nuclear and ion channel sensing, and their crosstalk, is critical to advancing our knowledge of cell migration in health and disease.

STING is crucial for the survival of RUNX1::RUNX1T1 leukemia cells

Even though acute myeloid leukemia (AML) patients with a RUNX1::RUNX1T1 (AE) fusion have a relatively favorable prognosis, approximately 50% relapse within 2.5 years and develop resistance to subsequent chemotherapy [1]. It is therefore imperative to identify novel therapeutic targets for AE leukemia to improve outcomes. In this study, we unveil that targeting STING effectively suppresses the growth of AE leukemia cells. Both genetic and pharmacological inhibition of STING lead to the diminish of AE leukemia cells. Importantly, in a mouse primary AE leukemia model, STING deletion significantly attenuates leukemogenesis and prolongs the animals' lifespan. Blocking the downstream inflammatory pathway of STING yields similar effects to STING inhibition in AE leukemia cells, highlighting the pivotal role of STING-dependent inflammatory responses in sustaining the survival of AE leukemia cells. Moreover, through a genome-wide CRISPR screen, we identified fatty acid desaturase 2 (FADS2) as a non-canonical factor downstream of STING inhibition that mediates cell death. Inhibition of STING releases FADS2 activity, consequently inducing the synthesis of polyunsaturated fatty acids (PUFAs) and triggering lipid peroxidation-associated cell death [2]. Taken together, these findings reveal a critical function of STING in the survival of AE-positive AML cells and suggest STING to be a potential therapeutic target for clinical intervention in these patients.

Advances in the prerequisite and consequence of STING downstream signalosomes

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is an evolving DNA-sensing mechanism involved in innate immunity and pathogen defense that has been optimized while remaining conserved. Aside from recognizing pathogens through conserved motifs, these receptors also detect aberrant or misplaced self-molecules as possible signs of perturbed homeostasis. Upon binding external or self-derived DNA, a mobile secondary messenger 2'3'-cyclic GMP-AMP (cGAMP) is produced by cGAS and in turn activates its adapter STING in the endoplasmic reticulum (ER). Resting-state or activated STING protein is finely restricted by multiple degradation machineries. The post-translational changes of the STING protein, along with the regulatory machinery of the secret routes, limit the onset, strength and sustention of STING signal. STING experiences a conformational shift and relocates with TBK1 from the ER to perinuclear vesicles containing transcription factors, provoking the transcription activity of IRF3/IFN-I and NF-κB pathways, as well as to initiate a number of cellular processes that have been shown to alter the immune landscape in cancer, such as autophagy, NLRP3 inflammasome, ER stress, and cell death. STING signal thus serves as a potent activator for immune mobilization yet also triggers immune-mediated pathology in tissues. Recent advances have established the vital role of STING in immune surveillance as well as tumorigenic process. This review provides an overview of the disparate outcomes of cancer attributed to the actions of pleiotropic and coordinated STING downstream signalosomes, along with the underlying mechanisms of STING function in pathologies, providing therapeutic implications for new approaches in hunt for the next generation of cancer immunotherapy base on STING.

Mechanism of immune activation mediated by genomic instability and its implication in radiotherapy combined with immune checkpoint inhibitors

Various genetic and epigenetic changes associated with genomic instability (GI), including DNA damage repair defects, chromosomal instability, and mitochondrial GI, contribute to development and progression of cancer. These alterations not only result in DNA leakage into the cytoplasm, either directly or through micronuclei, but also trigger downstream inflammatory signals, such as the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. Apart from directly inducing DNA damage to eliminate cancer cells, radiotherapy (RT) exerts its antitumor effects through intracellular DNA damage sensing mechanisms, leading to the activation of downstream inflammatory signaling pathways. This not only enables local tumor control but also reshapes the immune microenvironment, triggering systemic immune responses. The combination of RT and immunotherapy has emerged as a promising approach to increase the probability of abscopal effects, where distant tumors respond to treatment due to the systemic immunomodulatory effects. This review emphasizes the importance of GI in cancer biology and elucidates the mechanisms by which RT induces GI remodeling of the immune microenvironment. By elucidating the mechanisms of GI and RT-induced immune responses, we aim to emphasize the crucial importance of this approach in modern oncology. Understanding the impact of GI on tumor biological behavior and therapeutic response, as well as the possibility of activating systemic anti-tumor immunity through RT, will pave the way for the development of new treatment strategies and improve prognosis for patients.

The complexity of immune evasion mechanisms throughout the metastatic cascade

Metastasis, the spread of cancer from a primary site to distant organs, is an important challenge in oncology. This Review explores the complexities of immune escape mechanisms used throughout the metastatic cascade to promote tumor cell dissemination and affect organotropism. Specifically, we focus on adaptive plasticity of disseminated epithelial tumor cells to understand how they undergo phenotypic transitions to survive microenvironmental conditions encountered during metastasis. The interaction of tumor cells and their microenvironment is analyzed, highlighting the local and systemic effects that innate and adaptive immune systems have in shaping an immunosuppressive milieu to foster aggressive metastatic tumors. Effectively managing metastatic disease demands a multipronged approach to target the parallel and sequential mechanisms that suppress anti-tumor immunity. This management necessitates a deep understanding of the complex interplay between tumor cells, their microenvironment and immune responses that we provide with this Review.

Reuterin promotes pyroptosis in hepatocellular cancer cells through mtDNA-mediated STING activation and caspase 8 expression

Hepatocellular carcinoma (HCC) is the most common form of liver cancer with poor prognosis. The available drugs for advanced HCC are limited and substantial therapeutic advances including new drugs and new combination therapies are still in urgent need. In this study, we found that the major metabolite of Lactobacillus reuteri (L. reuteri), reuterin showed great anti-HCC potential and could help in sorafenib treatment. Reuterin treatment impaired mitophagy and caused the aberrant clustering of mitochondrial nucleoids to block mitochondrial DNA (mtDNA) replication and mitochondrial fission, which could promote mtDNA leakage and subsequent STING activation in HCC cells. STING could activate pyroptosis and necroptosis, while reuterin treatment also induced caspase 8 expression to inhibit necroptosis through cleaving RIPK3 in HCC cells. Thus, pyroptosis was the main death form in reuterin-treated HCC cells and STING suppression remarkably rescued the growth inhibitory effect of reuterin and concurrently knockdown caspase 8 synergized to restrain the induction of pyroptosis. In conclusion, our study explains the detailed molecular mechanisms of the antitumor effect of reuterin and reveals its potential to perform as a combinational drug for HCC treatment.

STING-Activating Small Molecular Therapeutics for Cancer Immunotherapy

Immuno-oncology has become a revolutionary strategy for cancer treatment. Therapeutic interventions based on adaptive immunity through immune checkpoint therapy or chimeric antigen receptor (CAR) T cells have received clinical approval for monotherapy and combination treatment in various cancers. Although these treatments have achieved clinical successes, only a minority of cancer patients show a response, highlighting the urgent need to discover new therapeutic molecules that could be exploited to improve clinical outcomes and pave the way for the next generation of immunotherapy. Given the critical role of the innate immune system against infection and cancer, substantial efforts have been dedicated to developing novel anticancer therapeutics that target these pathways. Targeting the stimulator of interferon genes (STING) pathway is a powerful strategy to generate a durable antitumor response, and activation of the adaptor protein STING induces the initiation of transcriptional cascades, thereby producing type I interferons, pro-inflammatory cytokines and chemokines. Various STING agonists, including natural or synthetic cyclic dinucleotides (CDNs), have been developed as anticancer therapeutics. However, since most CDNs are confined to intratumoral administration, there has been a great interest in developing non-nucleotide agonists for systemic treatment. Here, we review the current development of STING-activating therapeutics in both preclinical and clinical stages.

Novel insights into immune cells modulation of tumor resistance

Tumor resistance poses a significant challenge to effective cancer treatment, making it imperative to explore new therapeutic strategies. Recent studies have highlighted the profound involvement of immune cells in the development of tumor resistance. Within the tumor microenvironment, macrophages undergo polarization into the M2 phenotype, thus promoting the emergence of drug-resistant tumors. Neutrophils contribute to tumor resistance by forming extracellular traps. While T cells and natural killer (NK) cells exert their impact through direct cytotoxicity against tumor cells. Additionally, dendritic cells (DCs) have been implicated in preventing tumor drug resistance by stimulating T cell activation. In this review, we provide a comprehensive summary of the current knowledge regarding immune cell-mediated modulation of tumor resistance at the molecular level, with a particular focus on macrophages, neutrophils, DCs, T cells, and NK cells. The targeting of immune cell modulation exhibits considerable potential for addressing drug resistance, and an in-depth understanding of the molecular interactions between immune cells and tumor cells holds promise for the development of innovative therapies. Furthermore, we explore the clinical implications of these immune cells in the treatment of drug-resistant tumors. This review emphasizes the exploration of novel approaches that harness the functional capabilities of immune cells to effectively overcome drug-resistant tumors.

The role of the cGAS-STING signaling pathway in viral infections, inflammatory and autoimmune diseases

Pattern recognition receptors are an essential part of the immune system, which detect pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) and help shape both innate and adaptive immune responses. When dsDNA is present, cyclic GMP-AMP Synthase (cGAS) produces a second messenger called cyclic GMP-AMP (cGAMP), which then triggers an adaptor protein called STING, and eventually activates the expression of type I interferon (IFN) and pro-inflammatory cytokines in immune cells. The cGAS-STING signaling pathway has been receiving a lot of attention lately as a key immune-surveillance mediator. In this review, we summarize the present circumstances of the cGAS-STING signaling pathway in viral infections and inflammatory diseases, as well as autoimmune diseases. Modulation of the cGAS-STING signaling pathway provides potential strategies for treating viral infections, inflammatory diseases, and autoimmune diseases.

DAMP sensing and sterile inflammation: intracellular, intercellular and inter-organ pathways

Damage-associated molecular patterns (DAMPs) are endogenous molecules that are released from host cells as a result of cell death or damage. The release of DAMPs in tissues is associated with loss of tissue homeostasis. Sensing of DAMPs by innate immune receptors triggers inflammation, which can be beneficial in initiating the processes that restore tissue homeostasis but can also drive inflammatory diseases. In recent years, the sensing of intracellular DAMPs has received extensive attention in the field of sterile inflammation. However, emerging studies have shown that DAMPs that originate from neighbouring cells, and even from distal tissues or organs, also mediate sterile inflammatory responses. This multi-level sensing of DAMPs is crucial for intercellular, trans-tissue and trans-organ communication. Here, we summarize how DAMP-sensing receptors detect DAMPs from intracellular, intercellular or distal tissue and organ sources to mediate sterile inflammation. We also discuss the possibility of targeting DAMPs or their corresponding receptors to treat inflammatory diseases.

Make it STING: nanotechnological approaches for activating cGAS/STING as an immunomodulatory node in osteosarcoma

Osteosarcoma is a highly aggressive bone cancer primarily affecting children, adolescents, and young adults. The current gold standard for treatment of osteosarcoma patients consists of two to three rounds of chemotherapy, followed by extensive surgical intervention from total limb reconstruction to amputation, followed by additional rounds of chemotherapy. Although chemotherapy has advanced the treatment of osteosarcoma significantly, the overall 5-year survival rate in resistant forms of osteosarcoma is still below 20%. The interaction between cancer and the immune system has long been recognized as a critical aspect of tumour growth. Tumour cells within the tumour microenvironment (TME) suppress antitumour immunity, and immunosuppressive cells and cytokines provide the extrinsic factors of tumour drug resistance. Emerging research demonstrates an immunostimulatory role for the cGAS/STING pathway in osteosarcoma, typically considered an immune-cold or immunosuppressed cancer type. cGAS/STING signalling appears to drive an innate immune response against tumours and potentiates the efficacy of other common therapies including chemo and radiotherapy. Nanotechnological delivery systems for improved therapy delivery for osteosarcoma have also been under investigation in recent years. This review provides an overview of cGAS/STING signalling, its divergent roles in the context of cancer, and collates current research which activates cGAS/STING as an adjuvant immunomodulatory target for the treatment of osteosarcoma. It will also discuss current nanotechnological delivery approaches that have been developed to stimulate cGAS/STING. Finally, it will highlight the future directions that we believe will be central to the development of this transformative field.

Analysis of the role of POC1A in the development and progression of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common and deadly cancers worldwide. POC1 centriolar protein A (POC1A) is a gene encoding a protein that plays a key role in the centrosome, and is one of the two isoforms of POC1. To date, the expression of POC1A in HCC and its potential as a biomarker and tumor therapeutic target have not been examined. This study aimed to explore the effect of POC1A on patients with HCC and its potential mechanism.

Methods

This study investigated the role of POC1A in the occurrence and development of HCC. It analyzed the expression of POC1A in various types of HCC patients and its effect on survival using HCC patient information from the Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), the Human Protein Atlas (HPA), and the Hepatocellular Carcinoma Cell DataBase (HCCDB). It then explored the major enrichment pathways and gene functions of POC1A in HCC using the gene set enrichment analysis (GSEA) method and examined its protein-protein interactions (PPIs). Finally, it predicted the potential transcription factors (TFs) and target microRNAs (miRNAs) of POC1A, and analyzed the single nucleotide variation (SNV) and copy number variation (CNV) mutations of POC1A and the related genes in HCC, as well as their effects on immune cells.

Results

The results showed that POC1A was significantly overexpressed in HCC and was significantly associated with a poor prognosis. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that POC1A was mainly involved in the regulation of cell-cycle pathways and chromosome segregation functions. POC1A showed significant interactions with NUDC and PPARG, and they both had different numbers of SNV and CNV mutations in the HCC samples. In relation to immunity, the high expression of POC1A and its reciprocal genes may play an important role in B cells and macrophages.

Conclusions

In general, our findings suggest that POC1A overexpression could have an important effect on the development of HCC by regulating cell-cycle pathways, and that it could serve as a novel prognostic biomarker and a potential therapeutic target for HCC.

KaryoTap Enables Aneuploidy Detection in Thousands of Single Human Cells

Investigating chromosomal instability and aneuploidy within tumors is essential for understanding tumorigenesis and developing diagnostic and therapeutic strategies. Single-cell DNA sequencing technologies have enabled such analyses, revealing aneuploidies specific to individual cells within the same tumor. However, it has been difficult to scale the throughput of these methods to detect rare aneuploidies while maintaining high sensitivity. To overcome this deficit, we developed KaryoTap, a method combining custom targeted DNA sequencing panels for the Tapestri platform with a computational framework to enable detection of chromosome- and chromosome arm-scale aneuploidy (gains or losses) and copy number neutral loss of heterozygosity in all human chromosomes across thousands of single cells simultaneously. KaryoTap allows detecting gains and losses with an average accuracy of 83% for arm events and 91% for chromosome events. Importantly, together with chromosomal copy number, our system allows us to detect barcodes and gRNAs integrated into the cells' genome, thus enabling pooled CRISPR- or ORF-based functional screens in single cells. As a proof of principle, we performed a small screen to expand the chromosomes that can be targeted by our recently described CRISPR-based KaryoCreate system for engineering aneuploidy in human cells. KaryoTap will prove a powerful and flexible approach for the study of aneuploidy and chromosomal instability in both tumors and normal tissues.

Pentagalloylglucose alleviates acetaminophen-induced acute liver injury by modulating inflammation via cGAS-STING pathway

BACKGROUND

The cGAS-STING pathway is an important component of the innate immune system and plays significant role in acetaminophen-induced liver injury (AILI). Pentagalloylglucose (PGG) is a natural polyphenolic compound with various beneficial effects, including anti-cancer, antioxidant, anti-inflammatory, and liver-protective properties; however, whether it can be used for the treatment of AILI and the specific mechanism remain unclear.

MATERIALS AND METHODS

A cell culture model was created to study the effect of PGG on cGAS-STING pathway activation using various techniques including western blotting (WB), real-time quantitative polymerase chain reaction (RT-qPCR), immunofluorescence (IF), and immunoprecipitation (IP). The effect of PGG was investigated in vivo by establishing a dimethylxanthenone acetic acid (DMXAA)-mediated activation model. An AILI model was used to evaluate the hepatoprotective and therapeutic effects of PGG by detecting liver function indicators, liver histopathology, and cGAS-STING pathway-related indicators in mice with AILI.

RESULTS

PGG blocked cGAS-STING pathway activation in bone marrow-derived macrophages (BMDMs), THP-1 cells, and peripheral blood mononuclear cells (PBMCs) in vitro. Furthermore, PGG inhibited the generation of type I interferons (IFN-I) and the secretion of inflammatory factors in DMXAA-induced in vivo experiments. In addition, PGG also reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), improved liver tissue damage and apoptosis, and inhibited the cGAS-STING pathway activation caused by acetaminophen. In terms of the mechanism, PGG disrupted the connection between STING and TBK1.

CONCLUSIONS

PGG exerts a protective effect against AILI by blocking the cGAS-STING pathway, offering a promising treatment strategy.

Multimodal Spatial Profiling Reveals Immune Suppression and Microenvironment Remodeling in Fallopian Tube Precursors to High-Grade Serous Ovarian Carcinoma

High-Grade Serous Ovarian Cancer (HGSOC) originates from fallopian tube (FT) precursors. However, the molecular changes that occur as precancerous lesions progress to HGSOC are not well understood. To address this, we integrated high-plex imaging and spatial transcriptomics to analyze human tissue samples at different stages of HGSOC development, including p53 signatures, serous tubal intraepithelial carcinomas (STIC), and invasive HGSOC. Our findings reveal immune modulating mechanisms within precursor epithelium, characterized by chromosomal instability, persistent interferon (IFN) signaling, and dysregulated innate and adaptive immunity. FT precursors display elevated expression of MHC-class I, including HLA-E, and IFN-stimulated genes, typically linked to later-stage tumorigenesis. These molecular alterations coincide with progressive shifts in the tumor microenvironment, transitioning from immune surveillance in early STICs to immune suppression in advanced STICs and cancer. These insights identify potential biomarkers and therapeutic targets for HGSOC interception and clarify the molecular transitions from precancer to cancer.

Toxicity of extracellular cGAMP and its analogs to T cells is due to SLC7A1-mediated import

STING agonists are promising innate immune therapies and can synergize with adaptive immune checkpoint blockade therapies for cancer treatment, but their effectiveness is limited by the toxicity to activated T cells. An important class of STING agonists are analogs of the endogenous STING agonist, cGAMP, and while transporters for these small molecules are known in some cell types, how they enter and kill T cells remains unknown. Here, we identify the cationic amino acid transporter SLC7A1 as the dominant transporter of cGAMP and its analogs in activated primary mouse and human T cells. T cells upregulate this transporter upon activation and rapid proliferation to meet their high metabolic demand, but this comes at the cost of enabling increased transport and toxicity of cGAMP. To circumvent the essentiality of SLC7A1 to proliferating T cells, we found that the residues responsible for cGAMP transport are separate from the arginine binding pocket allowing us to perturb cGAMP transport and STING-activation mediated killing without impacting arginine transport. These results suggest that SLC7A1 is a potential target for alleviating T cell toxicity associated with cGAMP and its analogs.

Chromosomal instability increases radiation sensitivity

Continuous chromosome missegregation over successive mitotic divisions, known as chromosomal instability (CIN), is common in cancer. Increasing CIN above a maximally tolerated threshold leads to cell death due to loss of essential chromosomes. Here, we show in two tissue contexts that otherwise isogenic cancer cells with higher levels of CIN are more sensitive to ionizing radiation, which itself induces CIN. CIN also sensitizes HPV-positive and HPV-negative head and neck cancer patient derived xenograft (PDX) tumors to radiation. Moreover, laryngeal cancers with higher CIN prior to treatment show improved response to radiation therapy. In addition, we reveal a novel mechanism of radiosensitization by docetaxel, a microtubule stabilizing drug commonly used in combination with radiation. Docetaxel causes cell death by inducing CIN due to abnormal multipolar spindles rather than causing mitotic arrest, as previously assumed. Docetaxel-induced CIN, rather than mitotic arrest, is responsible for the enhanced radiation sensitivity observed in vitro and in vivo, challenging the mechanistic dogma of the last 40 years. These results implicate CIN as a potential biomarker and inducer of radiation response, which could provide valuable cancer therapeutic opportunities.

Statement of Significance

Cancer cells and laryngeal tumors with higher chromosome missegregation rates are more sensitive to radiation therapy, supporting chromosomal instability as a promising biomarker of radiation response.

Chromosomal instability as an architect of the cancer stemness landscape

Despite a critical role for tumor-initiating cancer stem cells (CSCs) in breast cancer progression, major questions remain about the properties and signaling pathways essential for their function. Recent discoveries highlighting mechanisms of CSC-resistance to the stress caused by chromosomal instability (CIN) may provide valuable new insight into the underlying forces driving stemness properties. While stress tolerance is a well-known attribute of CSCs, CIN-induced stress is distinctive since levels appear to increase during tumor initiation and metastasis. These dynamic changes in CIN levels may serve as a barrier constraining the effects of non-CSCs and shaping the stemness landscape during the early stages of disease progression. In contrast to most other stresses, CIN can also paradoxically activate pro-tumorigenic antiviral signaling. Though seemingly contradictory, this may indicate that mechanisms of CIN tolerance and pro-tumorigenic inflammatory signaling closely collaborate to define the CSC state. Together, these unique features may form the basis for a critical relationship between CIN and stemness properties.

Extracellular vesicle-associated DNA: ten years since its discovery in human blood

Extracellular vesicles (EVs) have emerged as key players in intercellular communication, facilitating the transfer of crucial cargo between cells. Liquid biopsy, particularly through the isolation of EVs, has unveiled a rich source of potential biomarkers for health and disease, encompassing proteins and nucleic acids. A milestone in this exploration occurred a decade ago with the identification of extracellular vesicle-associated DNA (EV-DNA) in the bloodstream of a patient diagnosed with pancreatic cancer. Subsequent years have witnessed substantial advancements, deepening our insights into the molecular intricacies of EV-DNA emission, detection, and analysis. Understanding the complexities surrounding the release of EV-DNA and addressing the challenges inherent in EV-DNA research are pivotal steps toward enhancing liquid biopsy-based strategies. These strategies, crucial for the detection and monitoring of various pathological conditions, particularly cancer, rely on a comprehensive understanding of why and how EV-DNA is released. In our review, we aim to provide a thorough summary of a decade's worth of research on EV-DNA. We will delve into diverse mechanisms of EV-DNA emission, its potential as a biomarker, its functional capabilities, discordant findings in the field, and the hurdles hindering its clinical application. Looking ahead to the next decade, we envision that advancements in EV isolation and detection techniques, coupled with improved standardization and data sharing, will catalyze the development of novel strategies exploiting EV-DNA as both a source of biomarkers and therapeutic targets.

Human aneuploid cells depend on the RAF/MEK/ERK pathway for overcoming increased DNA damage

Aneuploidy is a hallmark of human cancer, yet the molecular mechanisms to cope with aneuploidy-induced cellular stresses remain largely unknown. Here, we induce chromosome mis-segregation in non-transformed RPE1-hTERT cells and derive multiple stable clones with various degrees of aneuploidy. We perform a systematic genomic, transcriptomic and proteomic profiling of 6 isogenic clones, using whole-exome DNA, mRNA and miRNA sequencing, as well as proteomics. Concomitantly, we functionally interrogate their cellular vulnerabilities, using genome-wide CRISPR/Cas9 and large-scale drug screens. Aneuploid clones activate the DNA damage response and are more resistant to further DNA damage induction. Aneuploid cells also exhibit elevated RAF/MEK/ERK pathway activity and are more sensitive to clinically-relevant drugs targeting this pathway, and in particular to CRAF inhibition. Importantly, CRAF and MEK inhibition sensitize aneuploid cells to DNA damage-inducing chemotherapies and to PARP inhibitors. We validate these results in human cancer cell lines. Moreover, resistance of cancer patients to olaparib is associated with high levels of RAF/MEK/ERK signaling, specifically in highly-aneuploid tumors. Overall, our study provides a comprehensive resource for genetically-matched karyotypically-stable cells of various aneuploidy states, and reveals a therapeutically-relevant cellular dependency of aneuploid cells.

RCC1 depletion drives protein transport defects and rupture in micronuclei

Micronuclei (MN) are a commonly used marker of chromosome instability that form when missegregated chromatin recruits its own nuclear envelope (NE) after mitosis. MN frequently rupture, which results in genome instability, upregulation of metastatic genes, and increased immune signaling. MN rupture is linked to NE defects, but the cause of these defects is poorly understood. Previous work from our lab found that chromosome identity correlates with rupture timing for small MN, i.e. MN containing a short chromosome, with more euchromatic chromosomes forming more stable MN with fewer nuclear lamina gaps. Here we demonstrate that histone methylation promotes rupture and nuclear lamina defects in small MN. This correlates with increased MN size, and we go on to find that all MN have a constitutive nuclear export defect that drives MN growth and nuclear lamina gap expansion, making the MN susceptible to rupture. We demonstrate that these export defects arise from decreased RCC1 levels in MN and that additional loss of RCC1 caused by low histone methylation in small euchromatic MN results in additional import defects that suppress nuclear lamina gaps and MN rupture. Through analysis of mutational signatures associated with early and late rupturing chromosomes in the Pan-Cancer Analysis of Whole Genomes (PCAWG) dataset, we identify an enrichment of APOBEC and DNA polymerase E hypermutation signatures in chromothripsis events on early and mid rupturing chromosomes, respectively, suggesting that MN rupture timing could determine the landscape of structural variation in chromothripsis. Our study defines a new model of MN rupture where increased MN growth, caused by defects in protein export, drives gaps in nuclear lamina organization that make the MN susceptible to membrane rupture with long-lasting effects on genome architecture.

The role of cGAS-STING signaling in the development and therapy of head and neck squamous cell carcinoma

The cGAS-STING signaling pathway plays a critical role in innate immunity and defense against viral infections by orchestrating intracellular and adaptive immune responses to DNA. In the context of head and neck squamous cell carcinoma (HNSCC), this pathway has garnered significant attention due to its potential relevance in disease development and progression. HNSCC is strongly associated with risk factors such as smoking, heavy alcohol consumption, and human papillomavirus (HPV) infection. The presence or absence of HPV in HNSCC patients has been shown to have a profound impact on patient survival and prognosis, possibly due to the distinct biological characteristics of HPV-associated tumors. This review aims to provide a comprehensive overview of the current therapeutic approaches and challenges in HNSCC management, as well as the involvement of cGAS-STING signaling and its potential in the therapy of HNSCC. In addition, by advancing the present understanding of the mechanisms underlying this pathway, Activation of cGAS-STING-dependent inflammatory signaling downstream of chromosomal instability can exert both anti-tumoral and pro-tumoral effects in a cell-intrinsic manner, suggesting individualized therapy is of great importance. However, further exploration of the cGAS-STING signaling pathway is imperative for the effective management of HNSCC.

Stimulator of Interferon Genes-Activated Biomimetic Dendritic Cell Nanovaccine as a Chemotherapeutic Booster to Enhance Systemic Fibrosarcoma Treatment

Fibrosarcoma, a malignant mesenchymal tumor, is characterized by aggressive invasiveness and a high recurrence rate, leading to poor prognosis. Anthracycline drugs, such as doxorubicin (DOX), represent the frontline chemotherapy for fibrosarcoma, but often exhibit suboptimal efficacy. Recently, exploiting the stimulator of interferon genes (STING)-mediated innate immunity has emerged as a hopeful strategy for cancer treatment. Integrating chemotherapy with immunomodulators in chemo-immunotherapy has shown potential for enhancing treatment outcomes. Herein, we introduce an advanced dendritic cell (DC) nanovaccine, cGAMP@PLGA@CRTM (GP@CRTM), combined with low-dose DOX to enhance fibrosarcoma chemo-immunotherapy. The nanovaccine consists of poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulating the STING agonist 2,3-cGAMP (cGAMP@PLGA, GP) as its core, and a calreticulin (CRT) high-expressing fibrosarcoma cell membrane (CRTM) as the shell. Exposing CRT on the vaccine surface aids in recruiting DCs and stimulating uptake, facilitating efficient simultaneous delivery of STING agonists and tumor antigens to DCs. This dual delivery method effectively activates the STING pathway in DCs, triggering sustained immune stimulation. Simultaneously, low-dose DOX reduces chemotherapy-related side effects, directly kills a subset of tumor cells, and increases tumor immunogenicity, thus further amplifying immune therapeutic performance. Hence, these findings demonstrate the potential of DC nanovaccine GP@CRTM as a booster for chemotherapy. Synergistically combining low-dose DOX with the DC nanovaccine emerges as a powerful chemo-immunotherapy strategy, optimizing systemic fibrosarcoma therapy.

Mutations in the non-catalytic polyproline motif destabilize TREX1 and amplify cGAS-STING signaling

The cGAS-STING pathway detects cytosolic DNA and activates a signaling cascade that results in a type I interferon (IFN) response. The endoplasmic reticulum (ER)-associated exonuclease TREX1 suppresses cGAS-STING by eliminating DNA from the cytosol. Mutations that compromise TREX1 function are linked to autoinflammatory disorders, including systemic lupus erythematosus (SLE) and Aicardi-Goutières syndrome (AGS). Despite key roles in regulating cGAS-STING and suppressing excessive inflammation, the impact of many disease-associated TREX1 mutations-particularly those outside of the core catalytic domains-remains poorly understood. Here, we characterize a recessive AGS-linked TREX1 P61Q mutation occurring within the poorly characterized polyproline helix (PPII) motif. In keeping with its position outside of the catalytic core or ER targeting motifs, neither the P61Q mutation, nor aggregate proline-to-alanine PPII mutation, disrupts TREX1 exonuclease activity, subcellular localization, or cGAS-STING regulation in overexpression systems. Introducing targeted mutations into the endogenous TREX1 locus revealed that PPII mutations destabilize the protein, resulting in impaired exonuclease activity and unrestrained cGAS-STING activation. Overall, these results demonstrate that TREX1 PPII mutations, including P61Q, impair proper immune regulation and lead to autoimmune disease through TREX1 destabilization.

Targeting TREX1 Induces Innate Immune Response in Drug-Resistant Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is the most lethal type of lung cancer. Paradoxically, this tumor displays an initial exquisite response to chemotherapy; however, at relapse, the tumor is highly resistant to subsequent available therapies. Here, we report that the expression of three prime repair exonuclease 1 (TREX1) is strongly induced in chemoresistant SCLCs. Assay for transposase-accessible chromatin using sequencing and chromatin immunoprecipitation sequencing revealed a significant increase in chromatin accessibility and transcriptional activity of TREX1 gene locus in chemoresistant SCLCs. Analyses of human SCLC tumors and patient-derived xenografts (PDX) also showed an increase in TREX1 expression in postchemotherapy samples. TREX1 depletion caused the activation of cyclic GMP-AMP synthase stimulator of interferon gene pathway due to cytoplasmic accumulation of damage-associated double-stranded DNA, inducing immunogenicity and enhancing the sensitivity of drug-resistant cells to chemotherapy. These findings suggest TREX1 upregulation may partially contribute to the survival of resistant cells, and its inhibition may represent a promising therapeutic strategy to enhance antitumor immunity and potentiate the efficacy of chemotherapy and/or immunotherapy in chemoresistant SCLCs. Significance: In this study, we show that targeting TREX1 induces an innate immune response and resensitizes SCLC cells to chemotherapy, representing a promising novel target for "immunologically" cold tumors, such as SCLC.

Innovating Cancer Treatment Through Cell Cycle, Telomerase, Angiogenesis, and Metastasis

Cancer remains a formidable challenge in the field of medicine, necessitating innovative therapeutic strategies to combat its relentless progression. The cell cycle, a tightly regulated process governing cell growth and division, plays a pivotal role in cancer development. Dysregulation of the cell cycle allows cancer cells to proliferate uncontrollably. Therapeutic interventions designed to disrupt the cell cycle offer promise in restraining tumor growth and progression. Telomerase, an enzyme responsible for maintaining telomere length, is often overactive in cancer cells, conferring them with immortality. Targeting telomerase presents an opportunity to limit the replicative potential of cancer cells and hinder tumor growth. Angiogenesis, the formation of new blood vessels, is essential for tumor growth and metastasis. Strategies aimed at inhibiting angiogenesis seek to deprive tumors of their vital blood supply, thereby impeding their progression. Metastasis, the spread of cancer cells from the primary tumor to distant sites, is a major challenge in cancer therapy. Research efforts are focused on understanding the underlying mechanisms of metastasis and developing interventions to disrupt this deadly process. This review provides a glimpse into the multifaceted approach to cancer therapy, addressing critical aspects of cancer biology-cell cycle regulation, telomerase activity, angiogenesis, and metastasis. Through ongoing research and innovative strategies, the field of oncology continues to advance, offering new hope for improved treatment outcomes and enhanced quality of life for cancer patients.

Targeting chromosomal instability in patients with cancer

Chromosomal instability (CIN) is a hallmark of cancer and a driver of metastatic dissemination, therapeutic resistance, and immune evasion. CIN is present in 60-80% of human cancers and poses a formidable therapeutic challenge as evidenced by the lack of clinically approved drugs that directly target CIN. This limitation in part reflects a lack of well-defined druggable targets as well as a dearth of tractable biomarkers enabling direct assessment and quantification of CIN in patients with cancer. Over the past decade, however, our understanding of the cellular mechanisms and consequences of CIN has greatly expanded, revealing novel therapeutic strategies for the treatment of chromosomally unstable tumours as well as new methods of assessing the dynamic nature of chromosome segregation errors that define CIN. In this Review, we describe advances that have shaped our understanding of CIN from a translational perspective, highlighting both challenges and opportunities in the development of therapeutic interventions for patients with chromosomally unstable cancers.

Micronuclear collapse from oxidative damage

Chromosome-containing micronuclei are a hallmark of aggressive cancers. Micronuclei frequently undergo irreversible collapse, exposing their enclosed chromatin to the cytosol. Micronuclear rupture catalyzes chromosomal rearrangements, epigenetic abnormalities, and inflammation, yet mechanisms safeguarding micronuclear integrity are poorly understood. In this study, we found that mitochondria-derived reactive oxygen species (ROS) disrupt micronuclei by promoting a noncanonical function of charged multivesicular body protein 7 (CHMP7), a scaffolding protein for the membrane repair complex known as endosomal sorting complex required for transport III (ESCRT-III). ROS retained CHMP7 in micronuclei while disrupting its interaction with other ESCRT-III components. ROS-induced cysteine oxidation stimulated CHMP7 oligomerization and binding to the nuclear membrane protein LEMD2, disrupting micronuclear envelopes. Furthermore, this ROS-CHMP7 pathological axis engendered chromosome shattering known to result from micronuclear rupture. It also mediated micronuclear disintegrity under hypoxic conditions, linking tumor hypoxia with downstream processes driving cancer progression.

A p62-dependent rheostat dictates micronuclei catastrophe and chromosome rearrangements

Chromosomal instability (CIN) generates micronuclei-aberrant extranuclear structures that catalyze the acquisition of complex chromosomal rearrangements present in cancer. Micronuclei are characterized by persistent DNA damage and catastrophic nuclear envelope collapse, which exposes DNA to the cytoplasm. We found that the autophagic receptor p62/SQSTM1 modulates micronuclear stability, influencing chromosome fragmentation and rearrangements. Mechanistically, proximity of micronuclei to mitochondria led to oxidation-driven homo-oligomerization of p62, limiting endosomal sorting complex required for transport (ESCRT)-dependent micronuclear envelope repair by triggering autophagic degradation. We also found that p62 levels correlate with increased chromothripsis across human cancer cell lines and with increased CIN in colorectal tumors. Thus, p62 acts as a regulator of micronuclei and may serve as a prognostic marker for tumors with high CIN.

Application of PARP inhibitors combined with immune checkpoint inhibitors in ovarian cancer

The advent of polyadenosine diphosphate ribose polymerase inhibitors (PARPi) has brought about significant changes in the field of ovarian cancer treatment. However, in 2022, Rucaparib, Olaparib, and Niraparib, had their marketing approval revoked for third-line and subsequent therapies due to an increased potential for adverse events. Consequently, the exploration of new treatment modalities remains imperative. Recently, the integration of PARPi with immune checkpoint inhibitors (ICIs) has emerged as a potential remedy option within the context of ovarian cancer. This article offers a comprehensive examination of the mechanisms and applications of PARPi and ICIs in the treatment of ovarian cancer. It synthesizes the existing evidence supporting their combined use and discusses key considerations that merit attention in ongoing development efforts.

Role of PRMT1 and PRMT5 in Breast Cancer

Breast cancer is the most common cancer diagnosed in women worldwide. Early-stage breast cancer is curable in ~70-80% of patients, while advanced metastatic breast cancer is considered incurable with current therapies. Breast cancer is a highly heterogeneous disease categorized into three main subtypes based on key markers orientating specific treatment strategies for each subtype. The complexity of breast carcinogenesis is often associated with epigenetic modification regulating different signaling pathways, involved in breast tumor initiation and progression, particularly by the methylation of arginine residues. Protein arginine methyltransferases (PRMT1-9) have emerged, through their ability to methylate histones and non-histone substrates, as essential regulators of cancers. Here, we present an updated overview of the mechanisms by which PRMT1 and PRMT5, two major members of the PRMT family, control important signaling pathways impacting breast tumorigenesis, highlighting them as putative therapeutic targets.