Peritumoral B cells drive proangiogenic responses in HMGB1-enriched esophageal squamous cell carcinoma

Perivascular B cells link intestinal angiogenesis to immunity and to the gut-brain axis during neuroinflammation

Disruption of gut barrier function and intestinal immune cell homeostasis are increasingly considered critical players in pathogenesis of extra-intestinal inflammatory diseases, including multiple sclerosis (MS) and its prototypical animal model, the experimental autoimmune encephalomyelitis (EAE). Breakdown of epithelial barriers increases intestinal permeability and systemic dissemination of microbiota-derived molecules. However, whether the gut-vascular barrier (GVB) is altered during EAE has not been reported. Here, we demonstrate that endothelial cell proliferation and vessel permeability increase before EAE clinical onset, leading to vascular remodeling and expansion of intestinal villi capillary bed during disease symptomatic phase in an antigen-independent manner. Concomitant to onset of angiogenesis observed prior to neurological symptoms, we identify an increase of intestinal perivascular immune cells characterized by the surface marker lymphatic vessel endothelial hyaluronic acid receptor 1 (LYVE-1). LYVE-1+ is expressed more frequently on B cells that show high levels of CD73 and have proangiogenic properties. B cell depletion was sufficient to mitigate enteric blood endothelial cell proliferation following immunization for EAE. In conclusion, we propose that altered intestinal vasculature driven by a specialized LYVE-1+ B cell subset promotes angiogenesis and that loss of GVB function is implicated in EAE development and autoimmunity.

The mechanism of high mobility group box-1 protein and its bidirectional regulation in tumors

High-mobility group box-1 protein (HMGB1) is a nonhistone chromatin-related protein widely found in eukaryotic cells. It is involved in the transcription, replication, and repair of DNA to maintain nuclear homeostasis. It participates in cell growth, differentiation, and signal transduction. Recent studies showed that HMGB1 has a bidirectional regulatory effect on tumors by regulating TLR4/MYD88/NF-κB and RAGE/AMPK/mTOR signaling pathways. On the one hand, it is highly expressed in a variety of tumors, promoting tumor proliferation and invasion, while on the other hand, it induces autophagy and apoptosis of tumor cells and stimulates tumor-infiltrating lymphocytes to produce an anti-tumor immune response. At present, HMGB1 could be used as a target to regulate the drug resistance and prognostication in cancer. Clinical applications of HMGB1 in cancer need further in-depth studies.

Endothelial cells in tumor microenvironment: insights and perspectives

The tumor microenvironment is a highly complex and dynamic mixture of cell types, including tumor, immune and endothelial cells (ECs), soluble factors (cytokines, chemokines, and growth factors), blood vessels and extracellular matrix. Within this complex network, ECs are not only relevant for controlling blood fluidity and permeability, and orchestrating tumor angiogenesis but also for regulating the antitumor immune response. Lining the luminal side of vessels, ECs check the passage of molecules into the tumor compartment, regulate cellular transmigration, and interact with both circulating pathogens and innate and adaptive immune cells. Thus, they represent a first-line defense system that participates in immune responses. Tumor-associated ECs are involved in T cell priming, activation, and proliferation by acting as semi-professional antigen presenting cells. Thus, targeting ECs may assist in improving antitumor immune cell functions. Moreover, tumor-associated ECs contribute to the development at the tumor site of tertiary lymphoid structures, which have recently been associated with enhanced response to immune checkpoint inhibitors (ICI). When compared to normal ECs, tumor-associated ECs are abnormal in terms of phenotype, genetic expression profile, and functions. They are characterized by high proliferative potential and the ability to activate immunosuppressive mechanisms that support tumor progression and metastatic dissemination. A complete phenotypic and functional characterization of tumor-associated ECs could be helpful to clarify their complex role within the tumor microenvironment and to identify EC specific drug targets to improve cancer therapy. The emerging therapeutic strategies based on the combination of anti-angiogenic treatments with immunotherapy strategies, including ICI, CAR T cells and bispecific antibodies aim to impact both ECs and immune cells to block angiogenesis and at the same time to increase recruitment and activation of effector cells within the tumor.

HMGB1 in the interplay between autophagy and apoptosis in cancer

Lysosome-mediated autophagy and caspase-dependent apoptosis are dynamic processes that maintain cellular homeostasis, ensuring cell health and functionality. The intricate interplay and reciprocal regulation between autophagy and apoptosis are implicated in various human diseases, including cancer. High-mobility group box 1 (HMGB1), a nonhistone chromosomal protein, plays a pivotal role in coordinating autophagy and apoptosis levels during tumor initiation, progression, and therapy. The regulation of autophagy machinery and the apoptosis pathway by HMGB1 is influenced by various factors, including the protein's subcellular localization, oxidative state, and interactions with binding partners. In this narrative review, we provide a comprehensive overview of the structure and function of HMGB1, with a specific focus on the interplay between autophagic degradation and apoptotic death in tumorigenesis and cancer therapy. Gaining a comprehensive understanding of the significance of HMGB1 as a biomarker and its potential as a therapeutic target in tumor diseases is crucial for advancing our knowledge of cell survival and cell death.

HMGB1-activated tumor-associated macrophages promote migration and invasion via NF-κB/IL-6 signaling in oral squamous cell carcinoma

Tumor-associated macrophages (TAMs) are a highly abundant cell population within the tumor microenvironment of oral squamous cell carcinomas (OSCC). Recent studies have identified an intricate cross-talk between cancer cells and macrophages in the tumor microenvironment. However, the underlying mechanism remains unclear. High-mobility group box 1 (HMGB1) was linked to metastasis and an unfavorable prognosis in head and neck squamous cell carcinoma. Furthermore, it was significantly upregulated in moderately differentiated OSCC tissues and the OSCC cell lines CAL27 and SCC9. HMGB1 knockdown impedes the ability of TAMs to induce invasion and migration of OSCC cells. Phenotypic changes in macrophages were measured after incubation of supernatant from OSCC cells transfected with HMGB1 siRNA or supplemented with recombinant HMGB1. HMGB1 induced M1 polarization of macrophages and the secretion of IL-6 via the NF-κB pathway, contributing to the OSCC malignant migration. HMGB1 originating from OSCC cells, along with its downstream signaling pathways, holds promise as a potential therapeutic target for mitigating metastasis and improving the survival rate of OSCC.

The multifunctional protein HMGB1: 50 years of discovery

Fifty years since the initial discovery of HMGB1 in 1973 as a structural protein of chromatin, HMGB1 is now known to regulate diverse biological processes depending on its subcellular or extracellular localization. These functions include promoting DNA damage repair in the nucleus, sensing nucleic acids and inducing innate immune responses and autophagy in the cytosol and binding protein partners in the extracellular environment and stimulating immunoreceptors. In addition, HMGB1 is a broad sensor of cellular stress that balances cell death and survival responses essential for cellular homeostasis and tissue maintenance. HMGB1 is also an important mediator secreted by immune cells that is involved in a range of pathological conditions, including infectious diseases, ischaemia-reperfusion injury, autoimmunity, cardiovascular and neurodegenerative diseases, metabolic disorders and cancer. In this Review, we discuss the signalling mechanisms, cellular functions and clinical relevance of HMGB1 and describe strategies to modify its release and biological activities in the setting of various diseases.

The role of HMGB1 in digestive cancer

High mobility group box protein B1 (HMGB1) belongs to the HMG family, is widely expressed in the nucleus of digestive mucosal epithelial cells, mesenchymal cells and immune cells, and binds to DNA to participate in genomic structural stability, mismatch repair and transcriptional regulation to maintain normal cellular activities. In the context of digestive inflammation and tumors, HMGB1 readily migrates into the extracellular matrix and binds to immune cell receptors to affect their function and differentiation, further promoting digestive tract tissue injury and tumor development. Notably, HMGB1 can also promote the antitumor immune response. Therefore, these seemingly opposing effects in tumors make targeted HMGB1 therapies important in digestive cancer. This review focuses on the role of HMGB1 in tumors and its effects on key pathways of digestive cancer and aims to provide new possibilities for targeted tumor therapy.

A risk prognostic model for patients with esophageal squamous cell carcinoma basing on cuproptosis and ferroptosis

BACKGROUND

Cuproptosis, a form of copper-dependent programmed cell death recently presented by Tsvetkov et al., have been identified as a potential therapeutic target for refractory cancers and ferroptosis, a well-known form describing iron-dependent cell death. However, whether the crossing of cuproptosis-related genes and ferroptosis-related genes can introduce some new idea, thus being used as a novel clinical and therapeutic predictor in esophageal squamous cell carcinoma (ESCC) remains unknown.

METHODS

We collected ESCC patient data from the Gene Expression Omnibus and the Cancer Genome Atlas databases and used Gene Set Variation Analysis to score each sample based on cuproptosis and ferroptosis. We then performed weighted gene co-expression network analysis to identify cuproptosis and ferroptosis-related genes (CFRGs) and construct a ferroptosis and cuproptosis-related risk prognostic model, which we validated using a test group. We also investigated the relationship between the risk score and other molecular features, such as signaling pathways, immune infiltration, and mutation status.

RESULTS

Four CFRGs (MIDN, C15orf65, COMTD1 and RAP2B) were identified to construct our risk prognostic model. Patients were classified into low- and high-risk groups based on our risk prognostic model and the low-risk group showed significantly higher survival possibilities (P < 0.001). We used the "GO", "cibersort" and "ESTIMATE" methods to the above-mentioned genes to estimate the relationship among the risk score, correlated pathways, immune infiltration, and tumor purity.

CONCLUSION

We constructed a prognostic model using four CFRGs and demonstrated its potential clinical and therapeutic guidance value for ESCC patients.

Exploring the crosstalk between endothelial cells, immune cells, and immune checkpoints in the tumor microenvironment: new insights and therapeutic implications

The tumor microenvironment (TME) is a highly intricate milieu, comprising a multitude of components, including immune cells and stromal cells, that exert a profound influence on tumor initiation and progression. Within the TME, angiogenesis is predominantly orchestrated by endothelial cells (ECs), which foster the proliferation and metastasis of malignant cells. The interplay between tumor and immune cells with ECs is complex and can either bolster or hinder the immune system. Thus, a comprehensive understanding of the intricate crosstalk between ECs and immune cells is essential to advance the development of immunotherapeutic interventions. Despite recent progress, the underlying molecular mechanisms that govern the interplay between ECs and immune cells remain elusive. Nevertheless, the immunomodulatory function of ECs has emerged as a pivotal determinant of the immune response. In light of this, the study of the relationship between ECs and immune checkpoints has garnered considerable attention in the field of immunotherapy. By targeting specific molecular pathways and signaling molecules associated with ECs in the TME, novel immunotherapeutic strategies may be devised to enhance the efficacy of current treatments. In this vein, we sought to elucidate the relationship between ECs, immune cells, and immune checkpoints in the TME, with the ultimate goal of identifying novel therapeutic targets and charting new avenues for immunotherapy.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

CircRTN1 stimulates HMGB1 to regulate the malignant progression of papillary thyroid cancer by sponging miR-101-3p

BACKGROUND

The important role played by circular RNA (circRNA) in promoting the progression of papillary thyroid cancer (PTC) is attracting ever more attention among medical researchers. However, what the precise contribution is of circRTN1 in PTC progression remains unclear. The study was designed to analyze the role and mechanism of circRTN1 in regulating PTC progression.

METHODS

Human PTC cell lines (TPC-1 and IHH-4) and human thyroid normal cells (Nthy-ori 3-1) were used for in vitro assays. mRNA or protein expression of circRTN1, miR-101-3p, and high mobility group box 1 (HMGB1) were detected by quantitative real-time polymerase chain reaction or western blot. Cell proliferation was investigated by cell counting kit-8 assay, cell colony formation assay, and 5-ethynyl-2'-deoxyuridine assay. Wound-healing assay and transwell invasion assay were conducted to evaluate cell migration and invasion. Dual-luciferase reporter assay and RNA immunoprecipitation assay were applied to verify the target relations between circRTN1, miR-101-3p, and HMGB1. A xenograft tumor model was established to demonstrate the effect of circRTN1 on tumor formation in vivo. An immunohistochemistry assay was used to detect protein expression of HMGB1, ki-67, E-cadherin, and vimentin.

RESULTS

In comparison with healthy thyroid tissues and cells, PTC tissues and cells displayed high circRTN1 RNA expression and high HMGB1 mRNA and protein expression but low miR-101-3p expression. Silencing of circRTN1 suppressed PTC cell proliferation, migration, and invasion in vitro. MiR-101-3p was a target of circRTN1, and the knockdown of miR-101-3p relieved circRTN1 absence-mediated suppressive effects on PTC cell malignancy. HMGB1 was identified as a target gene of miR-101-3p, and overexpressed HMGB1 almost reverted the inhibitory impacts induced by miR-101-3p mimic in PTC cells. Moreover, circRTN1 silencing hampered tumor formation in vivo.

CONCLUSION

CircRTN1 depletion impeded PTC cell malignancy via the miR-101-3p/HMGB1 pathway, which provided a possible circRNA-targeted therapeutic strategy for PTC.

The redox protein HMGB1 in cell death and cancer

SIGNIFICANCE

As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer.

RECENT ADVANCES

HMGB1 is a non-histone nuclear protein that acts as a DNA chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depends on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on tumor types and stages.

CRITICAL ISSUES

A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions.

FUTURE DIRECTIONS

Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease.

The single cell transcriptional landscape of esophageal adenocarcinoma and its modulation by neoadjuvant chemotherapy

Immune checkpoint blockade has recently proven effective in subsets of patients with esophageal adenocarcinoma (EAC) but little is known regarding the EAC immune microenvironment. We determined the single cell transcriptional profile of EAC in 8 patients who were treatment-naive (n = 4) or had received neoadjuvant chemotherapy (n = 4). Analysis of 52,387 cells revealed 10 major cell subsets of tumor, immune and stromal cells. Prior to chemotherapy tumors were heavy infiltrated by T regulatory cells and exhausted effector T cells whilst plasmacytoid dendritic cells were markedly expanded. Two dominant cancer-associated fibroblast populations were also observed whilst endothelial populations were suppressed. Pathological remission following chemotherapy associated with broad reversal of immune abnormalities together with fibroblast transition and an increase in endothelial cells whilst a chemoresistant epithelial stem cell population correlated with poor response. These findings reveal features that underlie and limit the response to current immunotherapy and identify a range of novel opportunities for targeted therapy.

Co-expression of High-mobility group box 1 protein (HMGB1) and receptor for advanced glycation end products (RAGE) in the prognosis of esophageal squamous cell carcinoma

Esophageal cancer is a malignant type of cancer with a high mortality rate. The aim of this study is to determine co-expression patterns of High-mobility group box 1 protein (HMGB1) and receptor for advanced glycation end products (RAGE) in ESCC (esophageal squamous cell carcinoma) conditions and their prognostic role in cancer progression. The expression of HMGB1 and RAGE in ESCC tissues has been analyzed using qRT-PCR and Western blotting. Co-localized expression patterns of HMGB1 and RAGE in ESCC tissues were determined using immunohistochemistry and analyzed for clinical-pathological parameters. Overall survival was performed based on co-expression of HMGB1 and RAGE proteins. A higher expression pattern of HMGB1, and RAGE was observed at mRNA and protein level in the ESCC group compared to the adjacent tissue group. Expression of HMGB1 was significantly correlated with lymph node, metastasis, lymphatic invasion, and venous invasion (p < 0.05). RAGE expression exhibited a significant correlation with venous invasion. Overall survival was significantly shorter (P < 0.05) in the patients with co-expression of HMGB1 and RAGE compared to the patients without co-expression. A significant difference in the overall survival was evident between the patients with co-expression of HMGB1 and RAGE and the patients without coexpression. HMGB1 and RAGE expression patterns were associated with aggressive metastatic characteristics of ESCC. The co-expression of HMGB1 and RAGE was correlated with shorter survival times. Results concluded the co-expression patterns of HMGB1 and RAGE exhibited a prognostic relevance in ESCC conditions.

The Role of Tumor Microenvironment in Invasion and Metastasis of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in the world, with a high rate of morbidity. The invasion and metastasis of ESCC is the main reason for high mortality. More and more evidence suggests that metastasized cancer cells require cellular elements that contribute to ESCC tumor microenvironment (TME) formation. TME contains many immune cells and stromal components, which are critical to epithelial–mesenchymal transition, immune escape, angiogenesis/lymphangiogenesis, metastasis niche formation, and invasion/metastasis. In this review, we will focus on the mechanism of different microenvironment cellular elements in ESCC invasion and metastasis and discuss recent therapeutic attempts to restore the tumor-suppressing function of cells within the TME. It will represent the whole picture of TME in the metastasis and invasion process of ESCC.