Serum high mobility group box chromosomal protein 1 is associated with clinicopathologic features in patients with hepatocellular carcinoma

Emerging Roles of High-mobility Group Box-1 in Liver Disease

High-mobility group box-1 (HMGB1) is an architectural chromosomal protein with various roles depending on its cellular localization. Extracellular HMGB1 functions as a prototypical damage-associated molecular pattern that triggers inflammation and adaptive immune responses, mediated by specific cell surface receptors, including receptors for advanced glycation end products and toll-like receptors. Post-translational modifications of HMGB1 significantly impact various cellular processes that contribute to the pathogenesis of liver diseases. Recent studies have highlighted the close relationship between HMGB1 and the pathogenesis of acute liver injuries, including acetaminophen-induced liver injury, hepatic ischemia-reperfusion injury, and acute liver failure. In chronic liver diseases, HMGB1 plays a role in nonalcoholic fatty liver disease, alcohol-associated liver disease, liver fibrosis, and hepatocellular carcinoma. Targeting HMGB1 as a therapeutic approach, either by inhibiting its release or blocking its extracellular function, is a promising strategy for treating liver diseases. This review aimed to summarize the available evidence on HMGB1's role in liver disease, focusing on its multifaceted signaling pathways, impact on disease progression, and the translation of these findings into clinical interventions.

A patent review on HMGB1 inhibitors for the treatment of liver diseases

INTRODUCTION

HMGB1 is a non-histone chromatin protein released or secreted in response to tissue damage or infection. Extracellular HMGB1, as a crucial immunomodulatory factor, binds with several different receptors to innate inflammatory responses that aggravate acute and chronic liver diseases. The increased levels of HMGB1 have been reported in various liver diseases, highlighting that it represents a potential biomarker and druggable target for therapeutic development.

AREAS COVERED

This review summarizes the current knowledge on the structure, function, and interacting receptors of HMGB1 and its significance in multiple liver diseases. The latest patented and preclinical studies of HMGB1 inhibitors (antibodies, peptides, and small molecules) for liver diseases are summarized by using the keywords 'HMGB1,' 'HMGB1 antagonist, HMGB1-inhibitor,' 'liver disease' in Web of Science, Google Scholar, Google Patents, and PubMed databases in the year from 2017 to 2023.

EXPERT OPINIONS

In recent years, extensive research on HMGB1-dependent inflammatory signaling has discovered potent inhibitors of HMGB1 to reduce the severity of liver injury. Despite significant progress in the development of HMGB1 antagonists, few of them are approved for clinical treatment of liver-related diseases. Developing safe and effective specific inhibitors for different HMGB1 isoforms and their interaction with receptors is the focus of future research.

Advanced Biomarkers of Hepatotoxicity in Psychiatry: A Narrative Review and Recommendations for New Psychoactive Substances

One of the factors that increase the effectiveness of the pharmacotherapy used in patients abusing various types of new psychoactive substances (NPSs) is the proper functioning of the liver. However, the articles published to date on NPS hepatotoxicity only address non-specific hepatic parameters. The aim of this manuscript was to review three advanced markers of hepatotoxicity in psychiatry, namely, osteopontin (OPN), high-mobility group box 1 protein (HMGB1) and glutathione dehydrogenase (GDH, GLDH), and, on this basis, to identify recommendations that should be included in future studies in patients abusing NPSs. This will make it possible to determine whether NPSs do indeed have a hepatotoxic effect or whether other factors, such as additional substances taken or hepatitis C virus (HCV) infection, are responsible. NPS abusers are at particular risk of HCV infection, and for this reason, it is all the more important to determine what factors actually show a hepatotoxic effect in them.

The analysis of immunogenic cell death induced by ablation at different temperatures in hepatocellular carcinoma cells

Introduction: Ablation therapy is a commonly used tool in the management of hepatocellular carcinoma (HCC). After ablation, dying cancer cells release a variety of substances that trigger subsequent immune responses. Immunogenic cell death (ICD) has been a trending topic in recent years and has been discussed many times along with oncologic chemotherapy. However, the subject of ablative therapy and ICDs has been little discussed. The purpose of this study was to investigate whether ablation treatment induces ICD in HCC cells and whether different types of ICDs arise because of different ablation temperatures. Methods: Four different HCC cell lines (H22, Hepa-16, HepG2 and SMMC7221) were cultured and treated under different temperatures (-80°C, -40°C, 0°C, 37°C, and 60°C). Cell Counting Kit-8 assay was performed to analyze the viability of different cell lines. Apoptosis was detected by flow cytometry assay, and a few ICD-related cytokines (calreticulin, ATP, high mobility group box 1, and CXCL10) were detected by immunofluorescence or enzyme-linked immunosorbent assay. Results: The apoptosis rate of all kinds of cells increased significantly in -80°C group (p < 0.01) and 60°C group (p < 0.01). The expression levels of ICD-related cytokines were mostly significantly different between the different groups. For calreticulin, Hepa1-6 cells and SMMC7221 cells showed significantly higher protein expression levels in 60°C group (p < 0.01) and significantly lower protein expression levels -80°C group (p < 0.01). The ATP, high mobility group box 1 and CXCL10 expression levels were significantly higher in 60°C, -80°C and -40°C group of all four cell lines (p < 0.01). Conclusion: Different ablative treatments could induce different types of ICDs in HCC cells, providing a promising track for the development of individualized cancer therapies.

Extracellular HMGB1 as Inflammatory Mediator in the Progression of Mycoplasma Gallisepticum Infection

High-mobility group box 1 (HMGB1), a member of damage-associated molecular patterns (DAMPs), is involved in the immune regulation of several infectious diseases. Mycoplasma gallisepticum (MG) infection is proved to cause an abnormal immune response, but the role of HMGB1 in MG-induced chronic respiratory disease (CRD) is unclear. In this study, we found that HMGB1 was released from the nucleus to the extracellular in macrophages upon infection with MG. Extracellular HMGB1 bound to TLR2 activating the NF-κB pathway triggering a severe inflammatory storm and promoting the progression of MG infection. More importantly, TLR4 could be activated by HMGB1 to trigger immune disorders after TLR2 was silenced. This disease process could be interrupted by ethyl pyruvate (EP) inhibition of HMGB1 release or glycyrrhizic acid (GA). Furthermore, treatment of MG-infected chickens with GA significantly alleviated immune organ damage. In conclusion, we demonstrate that HMGB1 is secreted extracellularly to form an inflammatory environment upon MG infection, triggering a further cellular inflammatory storm in a positive feedback approach. Blocking MG-induced HMGB1 release or suppression downstream of the HMGB1-TLR2/TLR4 axis may be a promising novel strategy for the treatment of CRD. Furthermore, this study may provide a theoretical reference for understanding non-LPS-activated TLR4 events.

Innate lymphoid cells in early tumor development

Innate and adaptive immune cells monitor, recognize, and eliminate transformed cells. Innate lymphoid cells (ILCs) are innate counterparts of T cells that play a key role in many facets of the immune response and have a profound impact on disease states, including cancer. ILCs regulate immune responses by responding and integrating a wide range of signals within the local microenvironment. As primarily tissue-resident cells, ILCs are ideally suited to sense malignant transformation and initiate anti-tumor immunity. However, as ILCs have been associated with anti-tumor and pro-tumor activities in established tumors, they could potentially have dual functions during carcinogenesis by promoting or suppressing the malignant outgrowth of premalignant lesions. Here we discuss emerging evidence that shows that ILCs can impact early tumor development by regulating immune responses against transformed cells, as well as the environmental cues that potentially induce ILC activation in premalignant lesions.

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

Several B-cell subsets with distinct functions and polarized cytokine profiles that extend beyond antibody production have been reported in different cancers. Here we have demonstrated that proliferating B cells were predominantly found in the peritumoral region of esophageal squamous cell carcinoma (ESCC). These B cells were enriched in tumor nests with high expression of high-mobility group box 1 (HMGB1). High densities of peritumoral proliferating B cells and concomitantly high intratumoral HMGB1 expression showed improved prognostic significance, surpassing prognostic stratification of ESCC patients based on HMGB1 positivity alone. This striking association led us to set up models to test whether cancer-derived HMGB1 could shape tumor microenvironment via modulation on B cells. Overexpression of HMGB1 in ESCC cell lines (KYSE510 and EC18) enhanced proliferation and migration of B cells. Transcriptomic analysis showed that migratory B cells exhibited high enrichment of proangiogenic genes. VEGF expression in proliferating B cells was induced upon co-culture of HMGB1-overexpressing tumor cells and B cells. Secretome array profiling of conditioned media (CM) from the co-culture revealed rich expression of proangiogenic proteins. Consequently, incubation of human umbilical vein endothelial cells with CM promoted angiogenesis in tube formation and migration assays. HMGB1 inhibitor, glycyrrhizin, abolishes all the observed proangiogenic phenotypes. Finally, co-injection of B cells and CM with HMGB1-overexpressing tumor cells, but not with glycyrrhizin, significantly enhanced tumor growth associated with increased microvascular density in ESCC xenograft mice model. Our results indicate that cancer-derived HMGB1 elevates angiogenesis in ESCC by shifting the balance toward proangiogenic signals in proliferating B cells.

Potential effects of HMGB1 on viral replication and virus infection-induced inflammatory responses: A promising therapeutic target for virus infection-induced inflammatory diseases

Inflammatory responses, characterized by the overproduction of numerous proinflammatory mediators by immune cells, is essential to protect the host against invading pathogens. Excessive production of proinflammatory cytokines is a key pathogenic factor accounting for severe tissue injury and disease progression during the infection of multiple viruses, which are therefore termed as "cytokine storm". High mobility group box 1 (HMGB1), a ubiquitous DNA-binding protein released either over virus-infected cells or activated immune cells, may act as a proinflammatory cytokine with a robust capacity to potentiate inflammatory response and disease severity. Moreover, HMGB1 is a host factor that potentially participates in the regulation of viral replication cycles with complicated mechanisms. Currently, HMGB1 is regarded as a promising therapeutic target against virus infection. Here, we provide an overview of the updated studies on how HMGB1 is differentially manipulated by distinct viruses to regulate viral diseases.

Circ-CSPP1 knockdown suppresses hepatocellular carcinoma progression through miR-493-5p releasing-mediated HMGB1 downregulation

BACKGROUND

Hepatocellular carcinoma (HCC) accounts for over 80% of primary liver cancers and leads to a high death rate. Research on circular RNAs (circRNAs) suggests that circRNAs are promising biomarkers for cancer treatment. This study aimed to explore the function of a novel circRNA (circ-CSPP1) in HCC.

METHODS

Circ-CSPP1 was obtained from the microarray data downloaded from the Gene Expression Omnibus (GEO) database. The expression of circ-CSPP1, miR-493-5p and high mobility group box 1 (HMGB1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, colony formation ability, migration and invasion were monitored using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay and transwell assay, respectively. The protein levels of CyclinD1, Vimentin, matrix metallopeptidase 9 (MMP-9) and HMGB1 were detected by western blot. Xenograft models were established to investigate the function of circ-CSPP1 in vivo. The association between miR-493-5p and circ-CSPP1 or HMGB1 was predicted by the online tool starBase and ensured by dual-luciferase reporter assay.

RESULTS

The expression of circ-CSPP1 and HMGB1 was elevated, while the expression of miR-493-5p was declined in HCC tissues and cells. Circ-CSPP1 knockdown not only depleted HCC cell proliferation, formation, migration and invasion in vitro but also inhibited tumor growth in vivo. MiR-493-5p was a target of circ-CSPP1, and HMGB1 was a target of miR-493-5p. Rescue experiments presented that miR-493-5p deficiency reversed the effects of circ-CSPP1 knockdown, and HMGB1 overexpression reversed the effects of miR-493-5p restoration. Circ-CSPP1 sponged miR-493-5p to regulate HMGB1 expression.

CONCLUSION

Knockdown of circ-CSPP1 suppressed HCC development both in vitro and in vivo by upregulation of miR-493-5p and downregulation of HMGB1, hinting that circ-CSPP1 participated in HCC pathogenesis.

β-catenin has potential effects on the expression, subcellular localization, and release of high mobility group box 1 during bovine herpesvirus 1 productive infection in MDBK cell culture

High mobility group box 1 (HMGB1), a ubiquitous DNA-binding protein, can be released into extracellular space and function as a strong proinflammatory cytokine, which plays critical roles in the pathogenesis of various inflammatory diseases. Here, we showed that BoHV-1 productive infection in MDBK cells at later stage significantly increases HMGB1 mRNA expression and the protein release, but decreases the steady-state protein levels. Virus infection increases accumulation of HMGB1 protein in both nucleus and mitochondria, and relocalizes nuclear HMGB1 to assemble in highlighted foci via a confocal microscope assay. Interestingly, β-catenin-specific inhibitor iCRT14 is able to increase HMGB1 transcription and the protein release, and subcellular translocation in virus-infected cells. HMGB1-specific inhibitor, glycyrrhizin, could differentially affect virus gene transcription such as, the viral regulatory protein bICP0, bICP4 and bICP22, as well as glycoprotein gD. In summary, our data provides a novel mechanism that β-catenin signaling may regulate inflammatory response via affecting HMGB1 signaling.

In Situ Vaccination as a Strategy to Modulate the Immune Microenvironment of Hepatocellular Carcinoma

Hepatocellular Carcinoma (HCC) is a highly prevalent malignancy that develops in patients with chronic liver diseases and dysregulated systemic and hepatic immunity. The tumor microenvironment (TME) contains tumor-associated macrophages (TAM), cancer-associated fibroblasts (CAF), regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) and is central to mediating immune evasion and resistance to therapy. The interplay between these cells types often leads to insufficient antigen presentation, preventing effective anti-tumor immune responses. In situ vaccines harness the tumor as the source of antigens and implement sequential immunomodulation to generate systemic and lasting antitumor immunity. Thus, in situ vaccines hold the promise to induce a switch from an immunosuppressive environment where HCC cells evade antigen presentation and suppress T cell responses towards an immunostimulatory environment enriched for activated cytotoxic cells. Pivotal steps of in situ vaccination include the induction of immunogenic cell death of tumor cells, a recruitment of antigen-presenting cells with a focus on dendritic cells, their loading and maturation and a subsequent cross-priming of CD8+ T cells to ensure cytotoxic activity against tumor cells. Several in situ vaccine approaches have been suggested, with vaccine regimens including oncolytic viruses, Flt3L, GM-CSF and TLR agonists. Moreover, combinations with checkpoint inhibitors have been suggested in HCC and other tumor entities. This review will give an overview of various in situ vaccine strategies for HCC, highlighting the potentials and pitfalls of in situ vaccines to treat liver cancer.

Soluble High Mobility Group Box 1 (HMGB1) Is a Promising Biomarker for Prediction of Therapy Response and Prognosis in Advanced Lung Cancer Patients

BACKGROUND

High mobility group box 1 protein (HMGB1) is known for its significant elevation in a multitude of tumors and benign diseases. In this study, we investigated the relevance of soluble HMGB1 for the prediction and monitoring of therapy response as well as the estimation of prognosis in advanced lung cancer.

MATERIALS AND METHODS

In a retrospective study, HMGB1 levels were assessed by an enzyme-linked immunosorbent assay (ELISA) in the sera of 96 patients with advanced lung cancer (79 non-small-cell lung carcinoma (NSCLC); 14 small cell lung carcinoma (SCLC), 3 Mesothelioma) prior to cycles 1, 2, and 3 of chemotherapy and correlated with radiological therapy response after 2 and 4 cycles as well as with overall survival. In addition, HMGB1 was compared with established tumor markers cytokeratin 19-fragments (CYFRA 21-1), carcinoembryonic antigen (CEA) and neuron specific enolase (NSE).

RESULTS

While pretherapeutic HMGB1 levels were not predictive or prognostically relevant in NSCLC patients, HMGB1 values prior to cycles 2 and 3 as well as kinetics from cycle 1 to 2 discriminated significantly between patients with good (remission and stable disease) and poor response (progression). Performance of HMGB1 in receiver operating characteristic (ROC) analyses of NSCLC patients, with areas under the curve (AUCs) of 0.690 at cycle 2 and 0.794 at cycle 3 as well as sensitivities of 34.4% and 37.5%, respectively, for progression at 90% specificity, was comparable with the best tumor-associated antigen CYFRA 21-1 (AUCs 0.719 and 0.799; sensitivities of 37.5% and 41.7%, respectively). Furthermore, high concentrations of HMGB1 at cycles 2 and 3 were associated with shorter overall survival in NSCLC patients.

CONCLUSION

Soluble HMGB1 is a promising biomarker for prediction of therapy response and prognosis in advanced NSCLC patients.

Danger signals in liver injury and restoration of homeostasis

Damage-associated molecular patterns are signalling molecules involved in inflammatory responses and restoration of homeostasis. Chronic release of these molecules can also promote inflammation in the context of liver disease. Herein, we provide a comprehensive summary of the role of damage-associated molecular patterns as danger signals in liver injury. We consider the role of reactive oxygen species and reactive nitrogen species as inducers of damage-associated molecular patterns, as well as how specific damage-associated molecular patterns participate in the pathogenesis of chronic liver diseases such as alcohol-related liver disease, non-alcoholic steatohepatitis, liver fibrosis and liver cancer. In addition, we discuss the role of damage-associated molecular patterns in ischaemia reperfusion injury and liver transplantation and highlight current studies in which blockade of specific damage-associated molecular patterns has proven beneficial in humans and mice.

Hepatocellular carcinoma-derived high mobility group box 1 triggers M2 macrophage polarization via a TLR2/NOX2/autophagy axis

In many human cancers, including hepatocellular carcinoma (HCC), high density of infiltrating tumor-associated macrophages (TAM) is associated with poor prognosis. Most TAMs express a M2 phenotype subsequently supporting tumor growth. How tumor cells polarize these TAMs to a pro-tumor M2 phenotype is still poorly understood. Our previous studies have revealed that a Toll-like receptor 2 (TLR2)-dependent autophagy triggered by hepatoma-derived factors down-regulates NF-κB p65 and drives M2 macrophage differentiation. However, the underlying mechanisms and potential hepatoma-derived TLR2 ligands are not clear. Here, we provide evidence to reveal that NADPH oxidase 2 (NOX2)-dependent reactive oxygen species (ROS) generation is crucial for HCC-induced autophagy, NF-κB p65 down-regulation and M2 phenotype polarization in primary macrophages. This NOX2-generated ROS production in abolished in TLR2-deficient macrophages. HCC-derived or recombinant high-mobility group box 1 (HMGB1) is able to trigger this TLR2-mediated M2 macrophage polarization. Blockage of HMGB1 and ROS by inhibitors, ethyl pyruvate and N-acetylcysteine amide, respectively, significantly reduces both M2 macrophage accumulation and liver nodule formation in HCC-bearing mice. Our findings uncover a HMGB1/TLR2/NOX2/autophagy axis to trigger M2 macrophage polarization in HCC that can be considered as a novel therapeutic target for treating HCC.

A murine cellular model of necroinflammation displays RAGE-dependent cytokine induction that connects to hepatoma cell injury

Unresolved inflammation maintained by release of danger‐associated molecular patterns, particularly high‐mobility group box‐1 (HMGB1), is crucial for hepatocellular carcinoma (HCC) pathogenesis. To further characterize interactions between leucocytes and necrotic cancerous tissue, a cellular model of necroinflammation was studied in which murine Raw 264.7 macrophages or primary splenocytes were exposed to necrotic lysates (N‐lys) of murine hepatoma cells or primary hepatocytes. In comparison to those derived from primary hepatocytes, N‐lys from hepatoma cells were highly active—inducing in macrophages efficient expression of inflammatory cytokines like C‐X‐C motif ligand‐2 , tumor necrosis factor‐α, interleukin (IL)‐6 and IL‐23‐p19. This activity associated with higher levels of HMGB1 in hepatoma cells and was curbed by pharmacological blockage of the receptor for advanced glycation end product (RAGE)/HMGB1 axis or the mitogen‐activated protein kinases ERK1/2 pathway. Analysis of murine splenocytes furthermore demonstrated that N‐lys did not comprise of functionally relevant amounts of TLR4 agonists. Finally, N‐lys derived from hepatoma cells supported inflammatory splenic Th17 and Th1 polarization as detected by IL‐17, IL‐22 or interferon‐γ production. Altogether, a straightforward applicable model was established which allows for biochemical characterization of immunoregulation by HCC necrosis in cell culture. Data presented indicate a remarkably inflammatory capacity of necrotic hepatoma cells that, at least partly, depends on the RAGE/HMGB1 axis and may shape immunological properties of the HCC microenvironment.

High Mobility Group Box 1 in Human Cancer

High mobility group box 1 (HMGB1) is an extremely versatile protein that is located predominantly in the nucleus of quiescent eukaryotic cells, where it is critically involved in maintaining genomic structure and function. During cellular stress, however, this multifaceted, cytokine-like protein undergoes posttranslational modifications that promote its translocation to the cytosol, from where it is released extracellularly, either actively or passively, according to cell type and stressor. In the extracellular milieu, HMGB1 triggers innate inflammatory responses that may be beneficial or harmful, depending on the magnitude and duration of release of this pro-inflammatory protein at sites of tissue injury. Heightened awareness of the potentially harmful activities of HMGB1, together with a considerable body of innovative, recent research, have revealed that excessive production of HMGB1, resulting from misdirected, chronic inflammatory responses, appears to contribute to all the stages of tumorigenesis. In the setting of established cancers, the production of HMGB1 by tumor cells per se may also exacerbate inflammation-related immunosuppression. These pro-inflammatory mechanisms of HMGB1-orchestrated tumorigenesis, as well as the prognostic potential of detection of elevated expression of this protein in the tumor microenvironment, represent the major thrusts of this review.

Impact of perioperative high mobility group box chromosomal protein 1 expression on long-term outcomes in patients with esophageal squamous cell carcinoma

BACKGROUND AND AIM

High mobility group box chromosomal protein-1 (HMGB-1) is a potential late mediator of sepsis and a possible risk factor for postoperative pulmonary complications after esophagectomy. This study aimed to determine the relationship between HMGB-1 and clinicopathological factors and long-term prognosis after esophagectomy for esophageal cancer.

METHODS

We measured perioperative serum HMGB-1 levels using ELISA and HMGB-1 protein by immunohistochemistry expression in resected specimens.

RESULTS

Postoperative serum HMGB-1 levels were significantly higher than preoperative levels. Preoperative serum HMGB-1 levels were significantly higher in patients with more intraoperative bleeding, longer intensive care unit stays, and postoperative pneumonia. Postoperative serum HMGB-1 levels were significantly higher in older patients and those with longer operation time and more intraoperative bleeding. There were significant differences in long-term outcomes according to postoperative but not preoperative serum HMGB-1 levels. Multivariate analysis demonstrated that advanced pathological stage, postoperative pulmonary complications, and higher postoperative serum HMGB-1 levels were independently associated with relapse-free survival and overall survival. Preoperative serum HMGB-1 levels were significantly higher in patients with high HMGB-1 expression than those with low HMGB-1 expression by immunohistochemistry, whereas such statistical differences were not observed in postoperative serum HMGB-1. There were no differences in relapse-free survival and overall survival according to HMGB-1 expression by immunohistochemistry. Serum HMGB-1 levels were significantly increased after esophagectomy for esophageal cancer.

CONCLUSION

Elevated postoperative serum HMGB-1, which was associated not only with poor long-term but also short-term outcomes such as postoperative complications, might serve as a potential marker for prognosis in esophageal cancer.

Involvement of Intracellular and Extracellular High-Mobility Group Box-1 in the Progression of Esophageal Squamous Cell Carcinoma

BACKGROUND

High-mobility group box-1 (HMGB1) is involved in a broad range of inflammatory responses and the progression of various types of malignancy. However, the roles of HMGB1 in the progression of esophageal squamous cell carcinoma (ESCC) are unclear. The aim of this study was to investigate the significance of intracellular and extracellular HMGB1 in ESCC.

METHODS

HMGB1 levels were measured in the tissue and plasma of patients with ESCC, or in ESCC cell lines and their conditioned medium. The effects of downregulation of intracellular HMGB1 or upregulation of extracellular HMGB1 on proliferation, cell migration, and invasion were evaluated using proliferation, transwell, and wound healing assays.

RESULTS

Downregulation of HMGB1 expression inhibited cell proliferation, migration, and invasion. On the other hand, upregulation of extracellular HMGB1 level by addition of recombinant HMGB1 promoted the migratory and invasive abilities of ESCC cells through increases of phosphorylation of the signal-regulated kinase 1/2 and NF-κBp65 proteins. These effects of extracellular HMGB1 were attenuated by treatment with recombinant soluble thrombomodulin, which adsorbs HMGB1. The expression of HMGB1 was significantly higher in tumor tissue (p = 0.008), and the concentration of HMGB1 in the plasma was significantly higher in patients with ESCC than in healthy volunteers (p = 0.04). Cancer-specific survival was worse in patients with high concentration of plasma HMGB1 (p = 0.01).

CONCLUSION

Increase of HMGB1 levels in tumor cells or plasma plays a crucial role in the malignant potential of ESCC. Intracellular and extracellular HMGB1 may be a therapeutic target in ESCC.

Validity of serum amyloid A and HMGB1 as biomarkers for early diagnosis of gastric cancer

Background and aim

Gastric carcinomais a frequent neoplasm with poor outcome, and its early detection would improve prognosis. This study was designed to evaluate the possible use of new biomarkers, namely SAA and HMGB1, for early diagnosis of gastric cancer.

Methods

A total of 100 patients presenting with gastric symptoms were included. All patients underwent upper endoscopic evaluation, histopathological diagnosis and serum CEA, SAA, and HMGB1 measurements.

Results

Patients were classed endoscopically with neoplastic, inflammatory, and normal-appearing gastric mucosa: 50, 25, and 25 patients, respectively. Histologically, half the patients had chronic gastritis and the remaining cases gastric carcinoma of diffuse (n=28) or intestinal (n=22) type. SAA at cutoff of 18.5 mg/L had the best validity to differentiate gastritis from gastric carcinoma, with AUC, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of 0.99, 98%, 100%, 100%, and 98%, respectively, followed by HMGB1 at cutoff of 14.5 pg/μL, with AUC, sensitivity, specificity, PPV, and NPV of 0.91, 70%, 96%, 94.6%, and 76.2%, respectively. Sensitivity, specificity, PPV, and NPV of serum CEA at cutoff of 2.9 ng/mL to differentiate gastritis from gastric carcinoma were 42%, 72%, 60%, and 55.4%, respectively, with AUC of 0.53. Nonetheless, higher serum levels of both SAA and HMGB1 reflected higher tumor grade (P=0.027 and P=0.016, respectively) and advanced tumor stage (P-OBrk-0.001 for both).

Conclusion

Serum levels of both SAA and HMGB1 could be of great value for early diagnosis of gastric carcinoma, comparable to the diagnostic role of serum CEA, which is not valid for early diagnosis of gastric cancer.

Role of High-Mobility Group Box-1 in Liver Pathogenesis

High-mobility group box 1 (HMGB1) is a highly abundant DNA-binding protein that can relocate to the cytosol or undergo extracellular release during cellular stress or death. HMGB1 has a functional versatility depending on its cellular location. While intracellular HMGB1 is important for DNA structure maintenance, gene expression, and autophagy induction, extracellular HMGB1 acts as a damage-associated molecular pattern (DAMP) molecule to alert the host of damage by triggering immune responses. The biological function of HMGB1 is mediated by multiple receptors, including the receptor for advanced glycation end products (RAGE) and Toll-like receptors (TLRs), which are expressed in different hepatic cells. Activation of HMGB1 and downstream signaling pathways are contributing factors in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), and drug-induced liver injury (DILI), each of which involves sterile inflammation, liver fibrosis, ductular reaction, and hepatic tumorigenesis. In this review, we will discuss the critical role of HMGB1 in these pathogenic contexts and propose HMGB1 as a bona fide and targetable DAMP in the setting of common liver diseases.

High mobility group box 1 can be used to monitor perioperative course in patients with liver cancer

OBJECTIVE

High mobility group box 1 (HMGB1) is produced by inflammation. Regarding liver injuries, HMGB1 is reportedly involved in liver regeneration. The present study investigated the use of HMGB1 as a postoperative marker of surgical course in patients with liver cancer.

METHODS

Patients were enrolled if they had liver cancer, had undergone liver surgery, and did not develop postsurgical complications. Patients who received emergency surgery or patients with unresectable cancerous lesions were excluded. Blood samples were preoperatively obtained as well as at 1 day, 1 week, and 4 weeks following surgery; white blood cell count, serum C-reactive protein, serum albumin, and serum HMGB1 levels were measured.

RESULTS

A total of 36 patients were included in this study. HMGB1 levels significantly changed over time, increasing from a median of 7.1 ng/ml (preoperatively) to 13.9 ng/ml at 1 week postoperatively, and then decreased to 6.3 ng/ml at 4 weeks postoperatively. Peak HMGB1 levels were delayed, and elevated HMGB1 levels persisted as compared with the changes in conventional markers.

CONCLUSIONS

HMGB1 indicates a unique perioperative inflammatory state in patients with liver cancer. Serum HMGB1 may serve as a marker for monitoring surgical course in patients undergoing surgery for liver cancer.

HMGB1 and SEPP1 as predictors of hepatocellular carcinoma in patients with viral C hepatitis: Effect of DAAs

BACKGROUND

Hepatitis C viral infection (HCV) and hepatocellular carcinoma (HCC) are potential health problems. New directly acting antivirals (DAAs) changed HCV treatment strategies. Selenoprotein P1 (SEPP1) is a hepatokine implicated in HCC pathogenesis. High mobility group box1 (HMGB1), a nuclear DNA-binding protein, involved in immune and inflammatory responses in HCV and HCC. Therefore, the aim of current study was to investigate HMGB1 and SEPP1 levels in HCV and HCV + HCC patients and exploring DAAs effect on them.

METHODS

15 healthy volunteers, 25 HCV and 25 HCV + HCC patients were included. Liver function tests, alpha fetoprotein (AFP), SEPP1 and HMGB1 serum levels were evaluated. For HCV group blood samples before and after treatment with sofosbuvir/daclatasvir combination were collected.

RESULTS

HMGB1 was significantly higher in HCV + HCC group than in control and HCV groups (p < .05). SEPP1 decreased significantly in HCV and HCV + HCC groups compared to control group (p < .001). SEPP1 significantly elevated after treatment with DAAs (p = .001). HMGB1 and SEPP1 were negatively correlated with each other in HCV group (p = .047). Logistic regression analysis showed that HMGB1 and SEPP1 could be used as predictors for HCC in HCV infected patients (p = .02,p = .002) respectively. Receiver operating characteristic curve (ROC) revealed HMGB1 had 32% sensitivity and 100% specificity in differentiating HCV from HCV + HCC patients, both SEPP1 and HMGB1 had high sensitivity (92%,60%) and 93% specificity in differentiating healthy from HCV + HCC group.

CONCLUSION

HMGB1 and SEPP1 are involved in pathogenesis of HCV and HCV induced HCC. Both of them could serve as predictive biomarkers for HCC in HCV patients.

High-Mobility Group Box-1 and Liver Disease

High‐mobility group box‐1 (HMGB1) is a ubiquitous protein. While initially thought to be simply an architectural protein due to its DNA‐binding ability, evidence from the last decade suggests that HMGB1 is a key protein participating in the pathogenesis of acute liver injury and chronic liver disease. When it is passively released or actively secreted after injury, HMGB1 acts as a damage‐associated molecular pattern that communicates injury and inflammation to neighboring cells by the receptor for advanced glycation end products or toll‐like receptor 4, among others. In the setting of acute liver injury, HMGB1 participates in ischemia/reperfusion, sepsis, and drug‐induced liver injury. In the context of chronic liver disease, it has been implicated in alcoholic liver disease, liver fibrosis, nonalcoholic steatohepatitis, and hepatocellular carcinoma. Recently, specific posttranslational modifications have been identified that could condition the effects of the protein in the liver. Here, we provide a detailed review of how HMGB1 signaling participates in acute liver injury and chronic liver disease.

Hepatitis B virus-X protein regulates high mobility group box 1 to promote the formation of hepatocellular carcinoma

Hepatitis B virus (HBV) infection is a risk factor for hepatocellular carcinoma (HCC). HBV X protein (HBx) is an important carcinogen for HBV-induced HCC. When the HBx gene is integrated into the host cell genome, it is difficult to eradicate. The identification of an effective target to inhibit the oncogenic function of HBx is therefore critically important. The present study demonstrated that HBx, particularly truncated HBx, was expressed in several HBV-derived cell lines (e.g., Hep3B and SNU423). By analyzing data from The Cancer Genome Atlas, it was revealed that high expression of high mobility group box 1 (HMGB1) was associated with the process and prognosis of HCC. In vitro experiments confirmed that HBx could regulate the expression of HMGB1 and knockdown of HMGB1 could decrease the ability of HBx to promote cellular proliferation. HBx could also upregulate six transcription factors (GATA binding protein 3, Erb-B2 receptor tyrosine kinase 3, heat shock transcription factor 1, nuclear factor κB subunit 1, TATA-box binding protein and Kruppel-like factor 4), which could directly regulate HMGB1. By analyzing genes that are co-expressed with HMGB1, several signaling pathways associated with the development of HCC were identified. HBx and HMGB1 were revealed to be involved in these pathways, which may be the mechanism by which HBx promotes HCC by regulating HMGB1. These findings suggested that HMGB1 may be an effective target for inhibiting HBV-induced HCC.

A multicenter matched case-control analysis on seven polymorphisms from HMGB1 and RAGE genes in predicting hepatocellular carcinoma risk

Based on 540 hepatocellular carcinoma patients and 540 age- and gender-matched controls, we tested the hypothesis that high mobility group protein box1 (HMGB1) and the receptor for advanced glycation end products (RAGE) genes are two potential candidate susceptibility genes for hepatocellular carcinoma in a multicenter hospital-based case-control analysis. The genotypes of seven widely-studied polymorphisms were determined, and their distributions respected the Hardy-Weinberg equilibrium. The mutant alleles of two polymorphisms, rs1045411 in HMGB1 gene and rs2070600 in RAGE gene, had significantly higher frequencies in patients than in controls (P < 0.001), with the power to detect this significance of being over 99.9%. Moreover, the above two polymorphisms increased the risk of developing hepatocellular carcinoma significantly, particularly for rs2070600 under the additive (odds ratio [OR] = 1.77; 95% confidence interval [CI]: 1.34-2.32; P < 0.001) and dominant (OR = 1.75; 95% CI: 1.23-2.50; P = 0.002) models after adjusting for body mass index, smoking and drinking. Haplotype analysis showed that the T-C-T haplotype (rs1045411-rs2249825-rs1415125) in HMGB1 gene was associated with a 2.47-fold (95% CI: 1.41-4.34; P = 0.002) increased risk of hepatocellular carcinoma compared with the commonest C-C-T haplotype after adjustment. In RAGE gene, the T-T-A-G (rs1800625-rs1800624-rs2070600-rs184003) (adjusted OR; 95% CI; P: 1.75; 1.02-3.03; 0.045) and T-T-A-T (adjusted OR; 95% CI; P: 1.95; 1.01-3.76; 0.048) haplotypes were associated with a marginally increased risk of hepatocellular carcinoma compared with the commonest T-T-G-G haplotype. In summary, we identified two risk-associated polymorphisms (rs1045411 and rs2070600), and more importantly a joint impact of seven polymorphisms from the HMGB1/RAGE axis in susceptibility to hepatocellular carcinoma.

HMGB1 links chronic liver injury to progenitor responses and hepatocarcinogenesis

Cell death is a key driver of disease progression and carcinogenesis in chronic liver disease (CLD), highlighted by the well-established clinical correlation between hepatocellular death and risk for the development of cirrhosis and hepatocellular carcinoma (HCC). Moreover, hepatocellular death is sufficient to trigger fibrosis and HCC in mice. However, the pathways through which cell death drives CLD progression remain elusive. Here, we tested the hypothesis that high-mobility group box 1 (HMGB1), a damage-associated molecular pattern (DAMP) with key roles in acute liver injury, may link cell death to injury responses and hepatocarcinogenesis in CLD. While liver-specific HMGB1 deficiency did not significantly affect chronic injury responses such as fibrosis, regeneration, and inflammation, it inhibited ductular/progenitor cell expansion and hepatocyte metaplasia. HMGB1 promoted ductular expansion independently of active secretion in a nonautonomous fashion, consistent with its role as a DAMP. Liver-specific HMGB1 deficiency reduced HCC development in 3 mouse models of chronic injury but not in a model lacking chronic liver injury. As with CLD, HMGB1 ablation reduced the expression of progenitor and oncofetal markers, a key determinant of HCC aggressiveness, in tumors. In summary, HMGB1 links hepatocyte death to ductular reaction, progenitor signature, and hepatocarcinogenesis in CLD.

MicroRNA-Mediated Regulation of HMGB1 in Human Hepatocellular Carcinoma

High-mobility group box 1 (HMGB1) is a potential therapeutic target and novel biomarker in a variety of malignant tumors, including hepatocellular carcinoma (HCC). More recently, a number of microRNAs (miRNAs) are identified as a class of regulators for broad control of HMGB1-mediated biological actions in eukaryotic cells. In this review article we will describe representative miRNAs involved in regulating the HMGB1 signaling pathways in HCC cell lines and/or animal models. We also propose the possible mechanisms underlying the miRNA/HMGB1 axis and discuss the future clinical significance of miRNAs targeting HMGB1 molecule for HCC therapy.

Serum HMGB1 concentrations at 4 weeks is a useful predictor of extreme poor prognosis for advanced hepatocellular carcinoma treated with sorafenib and hepatic arterial infusion chemotherapy

BACKGROUND

Biomarkers predicting the response to the anticancer treatment and prognosis in patients with advanced hepatocellular carcinoma (HCC) are required. Recently, high mobility group box 1 (HMGB1) was reported to promote HCC progression and be associated with poor prognosis for patients with HCC. The purpose of this study was to assess serum HMGB1 concentrations before and during sorafenib treatment or hepatic arterial infusion chemotherapy (HAIC) and to explore the ability of serum HMGB1 concentrations to predict prognosis.

METHODS

Serum HMGB1 concentrations were measured in 71 and 72 patients with advanced HCC treated with sorafenib and HAIC, respectively, to assess their usefulness for prediction of the response to the treatment and prognosis.

RESULTS

Multivariate analysis identified high HMGB1 at 4 weeks (P = 0.001), high α-fetoprotein (AFP) at baseline (P = 0.025), tumor liver occupying rate (P = 0.009) and modified RECIST (mRECIST, P < 0.0001) as independent predictors of poor overall survival in sorafenib treatment. High HMGB1 at 4 weeks (P = 0.025), vascular invasion to the hepatic vein (Vv) (P = 0.009), mRECIST (P < 0.0001) and Child-Pugh B (P = 0.004) were identified as independent predictors of poor overall survival in HAIC treatment. The concentrations of HMGB1 at baseline and 4 weeks were not correlated with conventional tumor markers and progressive disease assessed by mRECIST at 8 weeks.

CONCLUSIONS

These results suggest that serum HMGB1 at 4 weeks after the start of treatment might be a useful biomarker with added value to the conventional tumor marker and radiologic responses to predict poor overall survival in patients with advanced HCC treated with sorafenib or HAIC.

miR-320a regulates high mobility group box 1 expression and inhibits invasion and metastasis in hepatocellular carcinoma

BACKGROUND & AIMS

Several studies have shown that miR-320a induces apoptosis, inhibits cell proliferation, and affects cell cycle progression as a tumour suppressor in many cancers. However, the involvement of miR-320a in the invasion and metastasis of hepatocellular carcinoma (HCC) is still unknown.

METHODS

Endogenous miR-320a and high mobility group box 1 (HMGB1) expressions were assayed by real-time PCR. Luciferase activities were measured using a dual-luciferase reporter assay system. Western blots were used to determine the protein expressions of HMGB1, MMP2, and MMP9. Invasion and metastasis of tumour cells were, respectively, evaluated by the transwell invasion assay and the wound healing assay.

RESULTS

The expression of miR-320a was significantly decreased in 24 of 32 (75%) HCC tissues and associated with the invasion and metastasis of HCC. Furthermore, we demonstrated that HMGB1 was a direct target of miR-320a and there was a significant negative correlation between miR-320a and HMGB1 expression in HCC. Ectopic expression or inhibition of miR-320a potently regulated the invasion and metastasis of HCC cells in HMGB1-dependent manner.

CONCLUSIONS

Our results showed that miR-320a was involved in the invasion and metastasis by targeting HMGB1 and had an anti-metastasis effect in HCC.

Is serum high-mobility group box 1 (HMGB-1) level correlated with liver fibrosis in chronic hepatitis B?

BACKGROUND

High-mobility group box 1 (HMGB1), identified as an alarmin molecule, was shown to have a role in virus-triggered liver injury. We aimed to evaluate the association between serum levels of HMGB1 and liver fibrosis.

METHOD

This cross-sectional case-control study included 189 chronic hepatitis B (CHB) patients and 51 healthy controls. All patients underwent liver biopsy and modified Knodell scoring system used to determine the fibrosis level in CHB patients. Serum HMGB1 levels were determined with enzyme-linked immunosorbent assay (ELISA).

RESULTS

Mean serum HMGB1 levels of patients (58.1 ± 54.7) were found to be higher than those of the control group (7.1 ± 4.3) (P = .001). HMGB1 levels of patients with advanced-stage fibrosis (stage 4 and 5) were detected to be higher than those of patients with early-stage fibrosis (stage 1-3). However, this difference was not statistically significant (P > .05). Albumin levels of fibrosis 3 and 4 patients were lower than fibrosis 1 and 2 patients. ALT, HBV DNA, and AFP levels of fibrosis 5 patients were significantly higher than fibrosis 1 and 2 patients, and their platelet and albumin levels are lower than fibrosis 1 and 2 patients (P < .001). In a logistic regression model, fibrosis levels were correlated with ALT values and inversely correlated with albumin levels.

CONCLUSION

In this study, we demonstrated that serum HMGB1 levels increase in the early course of liver injury and this increase is not correlated with severity of the liver damage.

Association of high mobility group BOX-1 and receptor for advanced glycation endproducts with clinicopathological features of haematological malignancies: a systematic review

High-mobility group box 1 (HMGB1) is a versatile protein with nuclear and extracellular functions. In the extracellular milieu, HMGB1 binds to several receptors, notably the receptor for advanced glycation end-products (RAGE). The expressions of HMGB1 and RAGE have been described in a variety of cancers. However, the clinical values of HMGB1 and RAGE in haematological malignancies have yet to be evaluated. A systematic search through PubMed and the Web of Science for articles discussing the role of HMGB1 and RAGE in haematological malignancies produced 15 articles. Overexpression of HMGB1 was reported to be associated with malignancy and, in certain studies, poor prognosis and tumour aggressiveness. Only one included study investigated the clinical value of RAGE, in which no significant difference was found between expression of RAGE in CLL neoplastic cells and nonmalignant controls. The discussed associations of HMGB1 and RAGE with clinicopathological characteristics of patients with haematological malignancies warrants further investigation into the prognostic and diagnostic value of both of these molecules.

Clinical significance of expression of high mobility group protein B1 and Toll-like receptor 4 in esophageal squamous cell carcinoma

AIM: To detect the expression of high mobility group protein B1 (HMGB1) and Toll-like receptor 4 (TLR4) in human esophageal squamous cell carcinoma and analyze their clinical significance.

METHODS: The expression of HMGB1 and TLR4 was detected by EnVision immunohisto-

chemical staining method in 72 esophageal squamous carcinoma specimens and 15 matched normal tissue specimens. Statistical methods were used to analyze the relationship between the expression of HMGB1 and TLR4 and clinical and pathological parameters.

RESULTS: The expression of HMGB1 and TLR4 in esophageal squamous carcinoma tissues was significantly higher than that in matched normal tissues (P < 0.05). HMGB1 and TLR4 expression was positively associated with lymphatic metastasis and TNM stage (P < 0.05), but negatively correlated with tumor size and degree of differentiation. The expression of HMGB1 and TLR4 had a significant positive correlation (r = 0.377, P < 0.01).

CONCLUSION: The expression of HMGB1 and TLR4 in esophageal squamous carcinoma tissues is associated with lymphatic metastasis and TNM stage, and the joint detection of HMGB1 and TLR4 expression may help evaluate the degree of malignancy of esophageal squamous carcinoma. HMGB1/TLR may be used as important biological indicators reflecting the prognosis of esophageal cancer and important targets for therapy of esophageal cancer.

Novel mechanisms involving chemically modified tetracycline 3 cytotoxicity

Chemically modified tetracycline 3 (CMT-3) is a potential anticancer drug because of its retained matrix metalloproteinases inhibitory property. In the present study,we showed that CMT-3 significantly inhibited the growth and proliferation of human hepatocellular carcinoma HepG2 cells. Novel mechanisms including increased intracellular autophagy level and high-mobility group box 1 (HMGB1)release were involved. In addition, a major Danshen ingredient, tanshinone IIA sodium sulfonate (TSN-SS),significantly increased the cytotoxic effects of CMT-3 in HepG2 cells. Combining CMT-3 with TSN-SS led to enhanced accumulation of endogenous LC3-II, but reduced HMGB1 cytoplasmic translocation. Altogether, these findings suggest that autophagy and HMGB1 release may play important roles in the anticancer effect of CMT-3. As an ovel candidate for cancer therapy, CMT-3 may be used in combination with TSN-SS, which possibly facilitates the execution of a death signal (e.g. autophagy) and prevents the survival of an inducer (e.g. HMGB1 cytoplasmic translocation), thus improving its therapeutic effect.

Clinical Value of High Mobility Group Box 1 and the Receptor for Advanced Glycation End-products in Head and Neck Cancer: A Systematic Review

Introduction High mobility group box 1 is a versatile protein involved in gene transcription, extracellular signaling, and response to inflammation. Extracellularly, high mobility group box 1 binds to several receptors, notably the receptor for advanced glycation end-products. Expression of high mobility group box 1 and the receptor for advanced glycation end-products has been described in many cancers.

Objectives To systematically review the available literature using PubMed and Web of Science to evaluate the clinical value of high mobility group box 1 and the receptor for advanced glycation end-products in head and neck squamous cell carcinomas.

Data synthesis A total of eleven studies were included in this review. High mobility group box 1 overexpression is associated with poor prognosis and many clinical and pathological characteristics of head and neck squamous cell carcinomas patients. Additionally, the receptor for advanced glycation end-products demonstrates potential value as a clinical indicator of tumor angiogenesis and advanced staging. In diagnosis, high mobility group box 1 demonstrates low sensitivity.

Conclusion High mobility group box 1 and the receptor for advanced glycation end-products are associated with clinical and pathological characteristics of head and neck squamous cell carcinomas. Further investigation of the prognostic and diagnostic value of these molecules is warranted.

Damage-associated molecular patterns in cancer: a double-edged sword

Damage-associated molecular patterns (DAMPs) are released in response to cell death and stress, and are potent triggers of sterile inflammation. Recent evidence suggests that DAMPs may also have a key role in the development of cancer as well as in the host response to cytotoxic anti-tumor therapy. As such, DAMPs may exert protective functions by alerting the immune system to the presence of dying tumor cells, thereby triggering immunogenic tumor cell death. On the other hand, cell death and release of DAMPs may also trigger chronic inflammation and thereby promote the development or progression of tumors. Here, we will review the contribution of candidate DAMPs and their receptors and discuss the evidence for DAMPs as tumor-promoting and anti-tumor effectors as well as unsolved questions such as DAMP release from non-tumor cells as well as the existence of tumor-specific DAMPs.

HMGB1 promotes HCC progression partly by downregulating p21 via ERK/c-Myc pathway and upregulating MMP-2

High-mobility group box 1 (HMGB1) was found to be over-expressed in many kinds of human cancer, which binds with several receptors and activates RAGE-Ras-MAPK, Toll-like receptors, NF-κB, and Src family kinase signaling pathways and plays a crucial role in tumorigenesis and cancer progression. However, the function and mechanism of HMGB1 in hepatocellular carcinoma (HCC) remain unclear. The aim of this study was to investigate the effect of HMGB1 on HCC progression and explore new molecular mechanism. HMGB1 transient knockdown, stable knockdown, and re-expression were performed by transfection with specific siRNA, shRNA, or expression vector in HCCLM3 cells. Results showed that transient knockdown HMGB1 prevented cell proliferation, promoted apoptosis, induced S phase arrest, and inhibited migration and invasion in vitro, and stable knockdown HMGB1 inhibited xenograft growth in Balb/c athymic mice in vivo. Molecular mechanism investigation revealed that knockdown HMGB1 significantly reduced the activation of MAPKs, including ERK1/2, p38, SAPK/JNK, as well as MAPKKs (MEK1/2, SEK1) and its substrates (c-Jun, c-Myc); downregulated NF-κB/p65 expression and phosphorylation level; decreased MMP-2 expression and activity; and upregulated p21 expression. Interestingly, c-Myc was firstly found to be involved in the promoting function of HMGB1 on HCC progression, which provided a novel clue for the inhibitory effect of HMGB1 on p21 expression by a p53-independent pathway. Collectively, these findings indicated that HMGB1 promoted HCC progression partly by enhancing the ERK1/2 and NF-κB pathways, upregulating MMP-2, and downregulating p21 via an ERK/c-Myc pathway.

Key Role of DAMP in Inflammation, Cancer, and Tissue Repair

PURPOSE

This review aimed to take stock of the current status of research on damage-associated molecular pattern (DAMP) protein. We discuss the Janus-faced role of DAMP molecules in inflammation, cancer, and tissue repair. The high-mobility group box (HMGB)-1 and adenosine triphosphate proteins are well-known DAMP molecules and have been primarily associated with inflammation. However, as we shall see, recent data have linked these molecules to tissue repair. HMGB1 is associated with cancer-related inflammation. It activates nuclear factor kB, which is involved in cancer regulation via its receptor for advanced glycation end-products (RAGE), Toll-like receptors 2 and 4. Proinflammatory activity and tissue repair may lead to pharmacologic intervention, by blocking DAMP RAGE and Toll like receptor 2 and 4 role in inflammation and by increasing their concentration in tissue repair, respectively.

METHODS

We conducted a MEDLINE search for articles pertaining to the various issues related to DAMP, and we discuss the most relevant articles especially (ie, not only those published in journals with a higher impact factor).

FINDINGS

A cluster of remarkable articles on DAMP have appeared in the literature in recent years. Regarding inflammation, several strategies have been proposed to target HMGB1, from antibodies to recombinant box A, which interacts with RAGE, competing with the full molecule. In tissue repair, it was reported that the overexpression of HMGB1 or the administration of exogenous HMGB1 significantly increased the number of vessels and promoted recovery in skin-wound, ischemic injury.

IMPLICATIONS

Due to the bivalent nature of DAMP, it is often difficult to explain the relative role of DAMP in inflammation versus its role in tissue repair. However, this point is crucial as DAMP-related treatments move into clinical practice.

HMGB1 Promotes Hepatitis C Virus Replication by Interaction with Stem-Loop 4 in the Viral 5' Untranslated Region

High-mobility group box 1 (HMGB1) protein is a highly conserved nuclear protein involved in multiple human diseases, including infectious diseases, immune disorders, metabolic disorders, and cancer. HMGB1 is comprised of two tandem HMG boxes (the A box and the B box) containing DNA-binding domains and an acidic C-terminal peptide. It has been reported that HMGB1 enhances viral replication by binding to viral proteins. However, its role in hepatitis C virus (HCV) replication is unknown. Here, we show that HMGB1 promoted HCV replication but had no effect on HCV translation. RNA immunoprecipitation experiments indicated that the positive strand, not the negative strand, of HCV RNA interacted with HMGB1. HCV infection triggered HMGB1 protein translocation from the nucleus to the cytoplasm, in which it interacted with the HCV genome. Moreover, the A box of HMGB1 is the pivotal domain to interact with stem-loop 4 (SL4) of the HCV 5' untranslated region. Deletion of the HMGB1 A box abrogated the enhancement of HCV replication by HMGB1. Our data suggested that HMGB1 serves as a proviral factor of HCV to facilitate viral replication in hepatocytes by interaction with the HCV genome.

IMPORTANCE

Hepatitis C virus (HCV) is a major global health threat, affecting more than 170 million people infection worldwide. These patients are at high risk of developing severe liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Currently, no vaccine is available. Many host factors may be implicated in the pathogenesis of HCV-related diseases. In this study, we found a novel HCV RNA-binding protein, HMGB1, that promotes HCV RNA replication. Moreover, SL4 in the 5' untranslated region of the HCV genome is the key region for HMGB1 binding, and the A box of HMGB1 protein is the functional domain to interact with HCV RNA and enhance viral replication. HMGB1 appears to play an important role in HCV-related diseases, and further investigation is warranted to elucidate the specific actions of HMGB1 in HCV pathogenesis.

Relationship between high-mobility group box 1 overexpression in ovarian cancer tissue and serum: a meta-analysis

OBJECTIVE

To implement a meta-analysis to investigate the relationship between high-mobility group box 1 (HMGB1) overexpression in the tissue and serum of ovarian cancer patients, and to evaluate its prognostic significance.

METHODS

Searches were made of China National Knowledge Infrastructure, EMBASE, WanFang, PubMed, MEDLINE, and Web of Science databases up to August 2015, with no language or style restrictions. Reference lists of related studies were also carefully reviewed to identify additional articles.

RESULTS

The literature search identified a total of 12 relevant studies on HMGB1 expression for inclusion in the meta-analysis: seven in ovarian tumor tissue, four in ovarian tumor patient serum, and one in both tissue and serum. HMGB1 protein levels in ovarian cancer tissues were notably higher than those in normal ovarian tissues with no evidence of heterogeneity between studies (RD=0.64, 95% confidence interval (CI): 0.57-0.70, Z=18.70, P<0.00001, I (2)=15%), and also higher than those in benign tumor tissues with no evidence of heterogeneity between studies (RD=0.52, 95% CI: 0.43-0.61, Z=11.14, P<0.00001, I (2)=0). Serum HMGB1 levels were similarly significantly higher in ovarian cancer patients than those with benign tumors or normal ovaries. Pooled mean differences of HMGB1 in ovarian cancer patients compared with patients with benign tumors or normal ovaries were 99.32 with 95% CI: 67.82-130.81, Z=6.18, P<0.00001, and 95.34 with 95% CI: 62.11-128.57, Z=5.62, P<0.0001. The pooled relative risk of ovarian cancer with high vs low HMGB1 expression levels was 1.40 with 95% CI: 1.09-1.79, Z=2.66, P=0.008, heterogeneity I (2)=50%.

CONCLUSION

This meta-analysis suggested that HMGB1 levels in both tissue and serum of ovarian cancer patients were significantly higher than those of benign tumor and normal ovarian samples. High serum or tissue HMGB1 expression may therefore be an effective molecular marker for ovarian benign or malignant tumor diagnosis and patient prognosis.

Potential role of High mobility group box 1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and is characterized as a typical inflammation-related carcinoma. High mobility group box protein 1 (HMGB1), a non-histone DNA-binding protein, is identified as a potent proinflammatory mediator when presents extracellularly. Recently, a growing body of evidence indicates that HMGB1 plays a potential role in HCC, but many questions remain unanswered about the relationship between HMGB1 and HCC formation and development. This review focuses on the biological effect of HMGB1, and discusses the association of HMGB1 with HCC and potential use of strategies targeting HMGB1 in HCC treatment.

Clinical impact of high mobility group box 1 protein in epithelial ovarian cancer

PURPOSE

The aim of this study was to confirm the expression of high mobility group box 1 (HMGB1) in patients with epithelial ovarian cancer (EOC) and to evaluate the prognostic significance of HMGB1.

METHODS

A total of 74 patients with EOC comprised our cohort. Retrospectively collected tissue microarray from EOC patients treated with debulking surgery followed by taxane and platinum chemotherapy were analyzed for evaluation of the prognostic significance of HMGB1. Expression of HMGB1 was assessed by immunohistochemistry.

RESULTS

The positive staining was detected in 80% of EOC patients and the rate of high HMGB1 expression was 42%. In advanced stage, patients with high HMGB1 expression showed a poorer prognosis than low HMGB1 expression group [median progression-free survival (PFS), 10.8 vs. 21.7 months, P = 0.005]. High HMGB1 expression was an independent predictor for PFS (P = 0.024).

CONCLUSIONS

HMGB1 expression is expected as a promising biomarker for EOC and further studies are needed to assess potential roles in EOC.

Correlation of High Mobility Group Box-1 Protein (HMGB1) with Clinicopathological Parameters in Primary Retinoblastoma

HMGB1 is considered to be DNA chaperone as it binds without any specificity. It is the structural protein which alters nuclear homeostasis and genomic stability of chromatin. Its role in retinoblastoma (Rb) remains unclear. The aim of the present study was to evaluate the expression of HMGB1 protein in primary enucleated retinoblastomas. Expression of HMGB1 in 69 prospective cases of primary retinoblastoma were assessed by immunohistochemistry and reverse transcriptase PCR (RT-PCR) technique and correlated with clinicopathological parameters. Immunohistochemical staining revealed expression of HMGB1 in 55.07 % (38/69) cases. Semi-quantitative RT-PCR was performed on 31 fresh tumor tissues. mRNA expression was observed in 77.41 % (24/31) cases. Expression of HMGB1 was statistically significant with poor tumor differentiation (p = 0.0440) & optic nerve invasion (p = 0.0128). HMGB1 expression was frequently seen in poorly differentiated tumors and those with histopathological high risk factors. Therefore, HMGB1 may contribute to tumor invasiveness and could serve as a poor prognostic marker in Rb.

Circulating HMGB1 and RAGE as Clinical Biomarkers in Malignant and Autoimmune Diseases

High molecular group box 1 (HMGB1) is a highly conserved member of the HMG-box-family; abundantly expressed in almost all human cells and released in apoptosis; necrosis or by activated immune cells. Once in the extracellular space, HMGB1 can act as a danger associated molecular pattern (DAMP), thus stimulating or inhibiting certain functions of the immune system; depending on the “combinatorial cocktail” of the surrounding milieu. HMGB1 exerts its various functions through binding to a multitude of membrane-bound receptors such as TLR-2; -4 and -9; IL-1 and RAGE (receptor for advanced glycation end products); partly complex-bound with intracellular fragments like nucleosomes. Soluble RAGE in the extracellular space, however, acts as a decoy receptor by binding to HMGB1 and inhibiting its effects. This review aims to outline today’s knowledge of structure, intra- and extracellular functions including mechanisms of release and finally the clinical relevance of HMGB1 and RAGE as clinical biomarkers in therapy monitoring, prediction and prognosis of malignant and autoimmune disease.

High-mobility group box 1 expression and lymph node metastasis in intrahepatic cholangiocarcinoma

AIM: To evaluate the prognostic value of high-mobility group box 1 (HMGB1) expression in intrahepatic cholangiocarcinoma (IHCC) and the possible underlying mechanism.

METHODS: Tissue microarray was constructed from 65 IHCC patients. Immunohistochemistry was performed to validate expression of HMGB1 and Vascular endothelial growth factor C (VEGF-C). Real-time PCR and Western blot analyses were used to study transcript and protein levels. The interaction between HMGB1 and VEGF-C was evaluated by siRNA, real-time PCR, and enzyme-linked immuno assays. The correlation between HMGB1 expression and other clinicopathologic parameters was analyzed by χ² test, and the univariate as well as multivariate analyses were accomplished by Kaplan-Meier method and Cox-regression model, respectively.

RESULTS: Overall, overexpression of HMGB1 was found in 38/65 (58.8%) IHCCs, whereas VEGF-C overexpression was present in 30/65 (46.2%) cases. Overexpression of HMGB1 was significantly correlated with lymphatic microvessel density (P = 0.031, r = 0.268) and VEGF-C expression (P = 0.041, r = 0.254). With univariate analysis, both HMGB1 (P = 0.001) and VEGF-C (P = 0.004) were identified to be significantly associated with overall survival rate. Multivariate analysis indicated that HMGB1 could be served as an unfavorable independent prognostic factor in IHCCs (P = 0.005). siRNA knockdown of HMGB1 inhibited transforming growth factor-β-induced epithelial-mesenchymal transition (EMT) by elevating E-Cadherin expression and reducing expression of N-Cadherin, Vimentin and Snail in RBE cells. Further in vitro study revealed that HMGB1 silencing significantly decreased the level of VEGF-C, whereas the recombinant HMGB1 increased the VEGF-C level in RBE cells (both P < 0.05), which suggested that HMGB1 could promote lymphatic microvessel density, and subsequently lymphatic invasion, via promoting VEGF-C expression.

CONCLUSION: Our results define an important role of HMGB1 in the progression of cholangiocarcinoma, and HMGB1 may serve as a prognostic marker for IHCC patients.

High mobility group box-1 and its clinical value in breast cancer

BACKGROUND

High mobility group box-1 (HMGB1) is a factor regulating malignant tumorigenesis, proliferation, and metastasis, and is associated with poor clinical pathology in various human cancers. We investigated the differential concentrations of HMGB1 in tissues and sera, and their clinical value for diagnosis in patients with breast cancer, benign breast disease, and healthy individuals.

METHODS

HMGB1 levels in tumor tissues, adjacent normal tissues, and benign breast disease tissues was detected via immunohistochemistry. Serum HMGB1 was measured using an enzyme-linked immunosorbent assay in 56 patients with breast cancer, 25 patients with benign breast disease, and 30 healthy control subjects. The clinicopathological features of the patients were compared. Tissues were evaluated histopathologically by pathologists.

RESULTS

HMGB1 levels in the tissues and sera of patients with breast cancer were significantly higher than those in patients with benign breast disease or normal individuals. The 56 cancer patients were classified as having high tissue HMGB1 levels (n=41) or low tissue HMGB1 levels (n=15), but the corresponsive serum HMGB1 in these two groups was not significantly different. HMGB1 levels in breast cancer tissues significantly correlated with differentiation grade, lymphatic metastasis, and tumor-node-metastasis stage, but not patient age, tumor size, or HER-2/neu expression; no association between serum HMGB1 levels and these clinicopathological parameters was found. The sensitivity and specificity of tissue HMGB1 levels for the diagnosis of breast cancer were 73.21% and 84.00%, respectively, while positive and negative predictive values were 91.11% and 58.33%.

CONCLUSION

HMGB1 might be involved in the development and progression of breast cancer and could be a supportive diagnostic marker for breast cancer. Serum HMGB1 could be a useful serological biomarker for diagnosis and screening of breast cancer.

Autophagy-mediated HMGB1 release promotes gastric cancer cell survival via RAGE activation of extracellular signal-regulated kinases 1/2

High mobility group box-B1 (HMGB1), an autophagy activator, is crucial in tumorigenesis. However, its extracellular role and signaling in gastric cancer remain unclear. Samples were collected from gastric cancer patients and healthy controls. Immunohistochemistry and immunocytochemistry were used to determine the localization of HMGB1 in gastric cancer tissues, four gastric carcinoma cell lines (BGC-823, SGC-7901, MKN-28 and MKN-45) and a gastric epithelial cell line GES-1. Western blot analysis and ELISA were used to assess the effects of gefitinib, an epidermal growth factor receptor inhibitor, on autophagy and HMGB1 release in BGC-823 cells. MTT assay and western blot analysis assessed the effects of extracellular HMGB1 on cell proliferation and signaling transduction. Released HMGB1 promoted proliferation through activation of ERK1/2 MAPK. HMGB1 expression in gastric cancer tissues and serum was significantly increased compared to the controls and healthy serum. Gastric carcinoma cells showed an increased HMGB1 in the nuclei and cytoplasm, whereas GES-1 cells exhibited a lower HMGB1 with nuclear localization. Gefitinib increased autophagy and cytoplasmic HMGB1 release from the BGC-823 cells. Extracellular HMGB1 in autophagic cell supernatant promoted proliferation that was abolished by glycyrrhizic acid, an HMGB1 inhibitor. BGC-823 cells incubated with HMGB1 had increased ERK1/2 phosphorylation, while levels of JNK, p38 or AKT were not affected. Blocking RAGE-HMGB1 interaction with antibody or siRNA suppressed the ERK1/2 activation and gastric cancer cell growth, indicating that RAGE-mediated ERK1/2 signaling was necessary for tumor progression.

Management of hepatocellular carcinoma: Predictive value of immunohistochemical markers for postoperative survival

Hepatocellular carcinoma (HCC) accounts for over 90% of all primary liver cancers. With an ever increasing incidence trend year by year, it has become the third most common cause of death from cancer worldwide. Hepatic resection is generally considered to be one of the most effective therapies for HCC patients, however, there is a high risk of recurrence in postoperative HCC. In clinical practice, there exists an urgent need for valid prognostic markers to identify patients with prognosis, hence the importance of studies on prognostic markers in improving the prediction of HCC prognosis. This review focuses on the most promising immunohistochemical prognostic markers in predicting the postoperative survival of HCC patients.

Emerging roles of interferon-stimulated genes in the innate immune response to hepatitis C virus infection

Infection with hepatitis C virus (HCV), a major viral cause of chronic liver disease, frequently progresses to steatosis and cirrhosis, which can lead to hepatocellular carcinoma. HCV infection strongly induces host responses, such as the activation of the unfolded protein response, autophagy and the innate immune response. Upon HCV infection, the host induces the interferon (IFN)-mediated frontline defense to limit virus replication. Conversely, HCV employs diverse strategies to escape host innate immune surveillance. Type I IFN elicits its antiviral actions by inducing a wide array of IFN-stimulated genes (ISGs). Nevertheless, the mechanisms by which these ISGs participate in IFN-mediated anti-HCV actions remain largely unknown. In this review, we first outline the signaling pathways known to be involved in the production of type I IFN and ISGs and the tactics that HCV uses to subvert innate immunity. Then, we summarize the effector mechanisms of scaffold ISGs known to modulate IFN function in HCV replication. We also highlight the potential functions of emerging ISGs, which were identified from genome-wide siRNA screens, in HCV replication. Finally, we discuss the functions of several cellular determinants critical for regulating host immunity in HCV replication. This review will provide a basis for understanding the complexity and functionality of the pleiotropic IFN system in HCV infection. Elucidation of the specificity and the mode of action of these emerging ISGs will also help to identify novel cellular targets against which effective HCV therapeutics can be developed.

Emerging roles of interferon-stimulated genes in the innate immune response to hepatitis C virus infection

Infection with hepatitis C virus (HCV), a major viral cause of chronic liver disease, frequently progresses to steatosis and cirrhosis, which can lead to hepatocellular carcinoma. HCV infection strongly induces host responses, such as the activation of the unfolded protein response, autophagy and the innate immune response. Upon HCV infection, the host induces the interferon (IFN)-mediated frontline defense to limit virus replication. Conversely, HCV employs diverse strategies to escape host innate immune surveillance. Type I IFN elicits its antiviral actions by inducing a wide array of IFN-stimulated genes (ISGs). Nevertheless, the mechanisms by which these ISGs participate in IFN-mediated anti-HCV actions remain largely unknown. In this review, we first outline the signaling pathways known to be involved in the production of type I IFN and ISGs and the tactics that HCV uses to subvert innate immunity. Then, we summarize the effector mechanisms of scaffold ISGs known to modulate IFN function in HCV replication. We also highlight the potential functions of emerging ISGs, which were identified from genome-wide siRNA screens, in HCV replication. Finally, we discuss the functions of several cellular determinants critical for regulating host immunity in HCV replication. This review will provide a basis for understanding the complexity and functionality of the pleiotropic IFN system in HCV infection. Elucidation of the specificity and the mode of action of these emerging ISGs will also help to identify novel cellular targets against which effective HCV therapeutics can be developed.