Non-histone nuclear factor HMGB1 as a therapeutic target in colorectal cancer

Caprylic Acid Inhibits High Mobility Group Box-1-Induced Mitochondrial Damage in Myocardial Tubes

Myocardial damage significantly impacts the prognosis of patients with cancer; however, the mechanisms of myocardial damage induced by cancer and its treatment remain unknown. We previously reported that medium-chain fatty acids (MCFAs) improve cancer-induced myocardial damage but did not evaluate the differences in effect according to MCFA type. Therefore, this study investigated the role of inflammatory cytokines in cancer-induced myocardial damage and the effects of three types of MCFAs (caprylic acid [C8], capric acid [C10], and lauric acid [C12]). In a mouse model, the C8 diet showed a greater effect on improving myocardial damage compared with C10 and C12 diets. Myocardial tubes differentiated from H9C2 cardiomyoblasts demonstrated increased mitochondrial oxidative stress, decreased membrane potential and mitochondrial volume, and inhibited myocardial tube differentiation following treatment with high-mobility group box-1 (HMGB1) but not interleukin-6 and tumor necrosis factor-α cytokines. However, HMGB1 treatment combined with C8 improved HMGB1-induced mitochondrial damage, enhanced autophagy, and increased mitochondrial biogenesis and maturation. However, these effects were only partial when combined with beta-hydroxybutyrate, a C8 metabolite. Thus, HMGB1 may play an important role in cancer-related myocardial damage. C8 counteracts HMGB1's effects and improves cancer-related myocardial damage. Further clinical studies are required to investigate the effects of C8.

Effects of High-Mobility Group Box-1 on Mucosal Immunity and Epithelial Differentiation in Colitic Carcinoma

Abnormalities in mucosal immunity are involved in the onset and progression of ulcerative colitis (UC), resulting in a high incidence of colorectal cancer (CRC). While high-mobility group box-1 (HMGB1) is overexpressed during colorectal carcinogenesis, its role in UC-related carcinogenesis remains unclear. In the present study, we investigated the role of HMGB1 in UC-related carcinogenesis and sporadic CRC. Both the azoxymethane colon carcinogenesis and dextran sulfate sodium colitis carcinogenesis models demonstrated temporal increases in mucosal HMGB1 levels. Activated CD8+ cells initially increased and then decreased, whereas exhausted CD8+ cells increased. Additionally, we observed increased regulatory CD8+ cells, decreased naïve CD8+ cells, and decreased mucosal epithelial differentiation. In the in vitro study, HMGB1 induced energy reprogramming from oxidative phosphorylation to glycolysis in CD8+ cells and intestinal epithelial cells. Furthermore, in UC dysplasia, UC-related CRC, and hyperplastic mucosa surrounding human sporadic CRC, we found increased mucosal HMGB1, decreased activated CD8+ cells, and suppressed mucosal epithelial differentiation. However, we observed increased activated CD8+ cells in active UC mucosa. These findings indicate that HMGB1 plays an important role in modulating mucosal immunity and epithelial dedifferentiation in both UC-related carcinogenesis and sporadic CRC.

Berberine Improves Cancer-Derived Myocardial Impairment in Experimental Cachexia Models by Targeting High-Mobility Group Box-1

Cardiac disorders in cancer patients pose significant challenges to disease prognosis. While it has been established that these disorders are linked to cancer cells, the precise underlying mechanisms remain elusive. In this study, we investigated the impact of cancerous ascites from the rat colonic carcinoma cell line RCN9 on H9c2 cardiomyoblast cells. We found that the ascites reduced mitochondrial volume, increased oxidative stress, and decreased membrane potential in the cardiomyoblast cells, leading to apoptosis and autophagy. Although the ascites fluid contained a substantial amount of high-mobility group box-1 (HMGB1), we observed that neutralizing HMGB1 with a specific antibody mitigated the damage inflicted on myocardial cells. Our mechanistic investigations revealed that HMGB1 activated both nuclear factor κB and phosphoinositide 3-kinases-AKT signals through HMGB1 receptors, namely the receptor for advanced glycation end products and toll-like receptor-4, thereby promoting apoptosis and autophagy. In contrast, treatment with berberine (BBR) induced the expression of miR-181c-5p and miR-340-5p while suppressing HMGB1 expression in RCN9 cells. Furthermore, BBR reduced HMGB1 receptor expression in cardiomyocytes, consequently mitigating HMGB1-induced damage. We validated the myocardial protective effects of BBR in a cachectic rat model. These findings underscore the strong association between HMGB1 and cancer cachexia, highlighting BBR as a promising therapeutic agent for myocardial protection through HMGB1 suppression and modulation of the signaling system.

Role of HMGB1 and its associated signaling pathways in human malignancies

The High-Mobility Group Box-1 (HMGB1), a non-histone chromatin-associated protein, plays a crucial role in cancer growth and response to therapy as it retains a pivotal role in promoting both cell death and survival. HMGB1 has been reported to regulate several signaling pathways engaged in inflammation, genome stability, immune function, cell proliferation, cell autophagy, metabolism, and apoptosis. However, the association between HMGB1 and cancer is complex and its mechanism in tumorigenesis needs to be further elucidated. This review aims to understand the role of HMGB1 in human malignancies and discuss the signaling pathways linked to this process to provide a comprehensive understanding on the association of HMGB1 with carcinogenesis. Further, we will review the role of HMGB1 as a target/biomarker for cancer therapy, the therapeutic strategies used to target this protein, and its potential role in preventing or treating cancers. In light of the recent growing evidence linking HMGB1 to cancer progression, we think that it may be suggested as a novel and emergent therapeutic target for cancer therapy. Hence, HMGB1 warrants paramount investigation to comprehensively map its role in tumorigenesis.

Thanksgiving to Yeast, the HMGB Proteins History from Yeast to Cancer

Yeasts have been a part of human life since ancient times in the fermentation of many natural products used for food. In addition, in the 20th century, they became powerful tools to elucidate the functions of eukaryotic cells as soon as the techniques of molecular biology developed. Our molecular understandings of metabolism, cellular transport, DNA repair, gene expression and regulation, and the cell division cycle have all been obtained through biochemistry and genetic analysis using different yeasts. In this review, we summarize the role that yeasts have had in biological discoveries, the use of yeasts as biological tools, as well as past and on-going research projects on HMGB proteins along the way from yeast to cancer.

Present Status, Challenges, and Prospects of Dihydromyricetin in the Battle against Cancer

Dihydromyricetin (DHM) is a natural flavonoid compound extracted from Ampelopsis grossedentata that has been used for centuries in traditional Chinese medicine. DHM has attracted intensive attention due to its numerous beneficial activities, such as hepatoprotection, cardioprotection, antioxidant, and anti-inflammation. In addition, DHM inhibits the progression of cancers such as lung cancer, hepatocellular cancer, breast cancer, melanoma, and malignant reproductive systems through multiple mechanisms, including antiangiogenesis, antiproliferation, apoptosis, and inhibition of invasion and migration. Notably, DHM also activates autophagy at different levels, exerting a dual-regulatory effect on cancers. Mechanistically, DHM can effectively regulate mammalian target of rapamycin (mTOR), noncoding RNA-mediated signaling, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway, nuclear factor-κB (NF-κB), p53, and endoplasmic reticulum stress (ER stress)-driven signaling in different types of cancers. DHM has also been shown to have inhibitory effects on various regulators that trigger epithelial–mesenchymal transition (EMT). Furthermore, DHM exhibits a remarkable anticancer reversal ability when used in combination with drugs such as adriamycin, nedaplatin, and other drugs. However, the low bioavailability of DHM limits its potential applications, which are improved through structural modification and the exploration of novel dosage forms. Therefore, DHM may become a promising candidate for treating malignancies alone or combined with conventional anticancer strategies used in clinical practice.

Oxidized high mobility group B-1 enhances metastability of colorectal cancer via modification of mesenchymal stem/stromal cells

High mobility group box-1 (HMGB1) is known to be a chemotactic factor for mesenchymal stem/stromal cells (MSCs), but the effect of post-translational modification on its function is not clear. In this study, we hypothesized that differences in the oxidation state of HMGB1 would lead to differences in the function of MSCs in cancer. In human colorectal cancer, MSCs infiltrating into the stroma were correlated with liver metastasis and serum HMGB1. In animal models, oxidized HMGB1 mobilized 3-fold fewer MSCs to subcutaneous tumors compared to reduced HMGB1. Reduced HMGB1 inhibited proliferation of mouse bone marrow MSCs (BM-MSCs) and induced differentiation into osteoblasts and vascular pericytes, whereas oxidized HMGB1 promoted proliferation and increased stemness, and no differentiation was observed. When BM-MSCs pretreated with oxidized HMGB1 were co-cultured with syngeneic cancer cells, cell proliferation and stemness of cancer cells were increased, and tumorigenesis and drug resistance were promoted. In contrast, co-culture with reduced HMGB1-pretreated BM-MSCs did not enhance stemness. In an animal orthotopic transplantation colorectal cancer model, oxidized HMGB1, but not reduced HMGB1, promoted liver metastasis with intratumoral MSC chemotaxis. Thus, oxidized HMGB1 reprograms MSCs and promotes cancer malignancy. The oxidized HMGB1-MSC axis may be an important target for cancer therapy.

Role of Glycated High Mobility Group Box-1 in Gastric Cancer

Advanced glycation end products (AGEs) are produced in response to a high-glucose environment and oxidative stress and exacerbate various diseases. Nε-(Carboxymethyl)lysine (CML) is an AGE that is produced by the glycation of lysine residues of proteins. There are a few reports on alterations in protein function due to CML modification; however, its association with cancer is not clear. We investigated the significance of CML modification in high mobility group box protein-1 (HMGB1), a cytokine that is significantly associated with cancer progression. Treatment of the gastric cancer cell lines TMK1 and MKN74 with glyoxal or glucose resulted in increased CML modification compared to untreated cells. CML-HMGB1 was modified via oxidation and more pronouncedly activated the receptor for AGE and downstream AKT and NF-κB compared to naïve HMGB1 and oxidized HMGB1. CML-HMGB1 bound with reduced affinity to DNA and histone H3, resulting in enhanced extranuclear translocation and extracellular secretion. Treatment of gastric cancer cells with CML-HMGB1 enhanced cell proliferation and invasion, sphere formation, and protection from thapsigargin-induced apoptosis, and decreased 5-FU sensitivity in comparison to HMGB1. Further, CML-HMGB1 was detected at various levels in all the 10 gastric cancer tumor specimens. HMGB1 levels correlated with primary tumor progression and distant metastasis, whereas CML-HMGB1 levels were associated with primary tumor progression, lymph node metastasis, distant metastasis, and stage. In addition, CML-HMGB1 levels correlated with oxidative stress in cancer tissues and resistance to neoadjuvant therapy. Therefore, CML modification of HMGB1 enhanced the cancer-promoting effect of HMGB1. In this study, CML-HMGB1 has been highlighted as a new therapeutic target, and analysis of the molecular structure of CML-HMGB1 is desired in the future.

Single- versus Dual-Targeted Nanoparticles with Folic Acid and Biotin for Anticancer Drug Delivery

Cancer is one of the major causes of death worldwide and its treatment remains very challenging. The effectiveness of cancer therapy significantly depends upon tumour-specific delivery of the drug. Nanoparticle drug delivery systems have been developed to avoid the side effects of the conventional chemotherapy. However, according to the most recent recommendations, future nanomedicine should be focused mainly on active targeting of nanocarriers based on ligand-receptor recognition, which may show better efficacy than passive targeting in human cancer therapy. Nevertheless, the efficacy of single-ligand nanomedicines is still limited due to the complexity of the tumour microenvironment. Thus, the NPs are improved toward an additional functionality, e.g., pH-sensitivity (advanced single-targeted NPs). Moreover, dual-targeted nanoparticles which contain two different types of targeting agents on the same drug delivery system are developed. The advanced single-targeted NPs and dual-targeted nanocarriers present superior properties related to cell selectivity, cellular uptake and cytotoxicity toward cancer cells than conventional drug, non-targeted systems and single-targeted systems without additional functionality. Folic acid and biotin are used as targeting ligands for cancer chemotherapy, since they are available, inexpensive, nontoxic, nonimmunogenic and easy to modify. These ligands are used in both, single- and dual-targeted systems although the latter are still a novel approach. This review presents the recent achievements in the development of single- or dual-targeted nanoparticles for anticancer drug delivery.

High Mobility Group Box Chromosomal Protein-1 Induces Myofibroblast Differentiation and Extracellular Matrix Production via RAGE, p38, JNK and AP-1 Signaling Pathways in Nasal Fibroblasts

BACKGROUND

Chronic rhinosinusitis is involved in myofibroblast differentiation and extracellular matrix (ECM) accumulation. High mobility group box chromosomal protein 1 (HMGB-1) is known to stimulate lung fibroblast to produce ECM in lung fibrosis. The aim of this study was to investigate whether HMGB-1 induces myofibroblast differentiation and ECM production in nasal fibroblasts and to identify the signal pathway.

METHODS

Human nasal fibroblasts were cultured. After stimulation with HMGB-1, expressions of α-smooth muscle actin (α-SMA) and fibronectin were determined by real-time PCR and western blot. Total collagen was measured by Sircol assay. To investigate signal pathway, various signal inhibitors and RAGE siRNA were used.

RESULTS

HMGB-1 increased α-SMA and fibronectin in mRNA and protein levels. It also increased collagen production. RAGE siRNA inhibited HMGB-1-induced α-SMA and fibronectin, and production of collagen. Furthermore, the inhibitors of RAGE downstream molecules such as p38, JNK and AP-1 also blocked the HMGB-1-induced effects.

CONCLUSIONS

HMGB-1 induces myofibroblast differentiation and ECM production in nasal fibroblast, which is mediated by RAGE, p38, JNK and AP-1 signal pathway. These results suggest that HMGB-1 may play an important role in tissue remodeling during chronic rhinosinusitis progression.

Receptor for Advanced Glycation End Products Acts as a Fuel to Colorectal Cancer Development

Receptor for advanced glycation end-products (RAGE) is a multiligand binding and single-pass transmembrane protein taken in diverse chronic inflammatory conditions. RAGE behaves as a pattern recognition receptor, which binds and is engaged in the cellular response to a variety of damage-associated molecular pattern molecules, as well as HMGB1, S100 proteins, and AGEs (advanced glycation end-products). The RAGE activation turns out to a formation of numerous intracellular signaling mechanisms, resulting in the progression and prolongation of colorectal carcinoma (CRC). The RAGE expression correlates well with the survival of colon cancer cells. RAGE is involved in the tumorigenesis, which increases and develops well in the stressed tumor microenvironment. In this review, we summarized downstream signaling cascade activated by the multiligand activation of RAGE, as well as RAGE ligands and their sources, clinical studies, and tumor markers related to RAGE particularly in the inflammatory tumor microenvironment in CRC. Furthermore, the role of RAGE signaling pathway in CRC patients with diabetic mellitus is investigated. RAGE has been reported to drive assorted signaling pathways, including activator protein 1, nuclear factor-κB, signal transducer and activator of transcription 3, SMAD family member 4 (Smad4), mitogen-activated protein kinases, mammalian target of rapamycin, phosphoinositide 3-kinases, reticular activating system, Wnt/β-catenin pathway, and Glycogen synthase kinase 3β, and even microRNAs.

Downregulation of miR-205 contributes to epithelial-mesenchymal transition and invasion in triple-negative breast cancer by targeting HMGB1-RAGE signaling pathway

Our aim was to study the regulatory molecule networks involved in the epithelial-to-mesenchymal transition and thus promoting the early onset of metastasis in triple-negative breast cancer (TNBC). Forty pairs of human TNBC and their adjacent normal breast tissues were analyzed by real-time PCR and immunochemistry to demonstrate the correlation between the miR-205 expression and clinicopathological characteristics. In vitro, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, cell migration, and invasion assay were used to detect the cell growth and invasive ability of TNBC cells after upregulation or downregulation of miR-205 expression. Luciferase reporter assay was used to confirm the potential target directly influenced by miR-205. Our results showed that miR-205 abnormal expression may be involved and associated with the biological traits of TNBC. Ectopic expression of miR-205 not only inhibited cell growth, but also suppressed migration and invasion of mesenchymal-like TNBC cells. In addition, we found that overexpression of miR-205 significantly suppressed HMGB1 by binding its 3′-untranslated region, and that miR-205 was inversely correlated with the expression of HMGB1 and RAGE in cell lines and clinical samples. Our study illustrated that miR-205 was a tumor suppressor in TNBC, which attenuated the viability and the acquisition of the epithelial-to-mesenchymal transition phenotype TNBC cells at least partially exerted through targeting of HMGB1–RAGE signaling pathway.

Differential Characteristics of HMGB2 Versus HMGB1 and their Perspectives in Ovary and Prostate Cancer

We have summarized common and differential functions of HMGB1 and HMGB2 proteins with reference to pathological processes, with a special focus on cancer. Currently, several "omic" approaches help us compare the relative expression of these 2 proteins in healthy and cancerous human specimens, as well as in a wide range of cancer-derived cell lines, or in fetal versus adult cells. Molecules that interfere with HMGB1 functions, though through different mechanisms, have been extensively tested as therapeutic agents in animal models in recent years, and their effects are summarized. The review concludes with a discussion on the perspectives of HMGB molecules as targets in prostate and ovarian cancers.

Quasi-ultrafine particles promote cell metastasis via HMGB1-mediated cancer cell adhesion

With increasingly severe air pollution, the aggravated health risks of particulate matter, especially ultrafine particles, are emerging as an urgent and sensitive topic. Considering the heterogeneity and complexity of ultrafine particles, there is insufficient evidence about their toxic effects and possible molecular mechanisms. To address this question, we analyzed the emission characteristics of quasi-ultrafine particles collected during winter in a typical coal-burning city, Taiyuan, and confirmed their contribution to lung cancer cell adhesion and metastasis. For the specific mechanism, we revealed that the endocytosis of quasi-ultrafine particles stimulated the release of HMGB1, induced NFκB-facilitated proinflammatory cytokine production through the interaction of HMGB1 with RAGE, and resulted in cancer-endothelial cell adhesion. These findings remind us of the potential effects of anthropogenic quasi-ultrafine particle pollution and provide a theoretical reference for the mitigation of tumorigenesis in a severe particulate matter contaminated environment.

Role of Metastasis-Related Genes in Cisplatin Chemoresistance in Gastric Cancer

The role of metastasis-related genes in cisplatin (CDDP) chemoresistance in gastric cancer is poorly understood. Here, we examined the expression of four metastasis-related genes (namely, c-met, HMGB1, RegIV, PCDHB9) in 39 cases of gastric cancer treated with neoadjuvant therapy with CDDP or CDDP+5-fluorouracil and evaluated its association with CDDP responsiveness. Comparison of CDDP-sensitive cases with CDDP-resistant cases, the expression of c-met, HMGB1, and PCDHB9 was correlated with CDDP resistance. Among them, the expression of HMGB1 showed the most significant correlation with CDDP resistance in multivariate analysis. Treatment of TMK-1 and MKN74 human gastric cancer cell lines with ethyl pyruvate (EP) or tanshinone IIA (TAN), which are reported to inhibit HMGB1 signaling, showed a 4–5-fold increase in inhibition by CDDP. Treatment with EP or TAN also suppressed the expression of TLR4 and MyD88 in the HMGB1 signal transduction pathway and suppressed the activity of NFκB in both cell lines. These results suggest that the expression of these cancer metastasis-related genes is also related to anticancer drug resistance and that suppression of HMGB1 may be particularly useful for CDDP sensitization.

Evaluation of Parameters for Cancer-Induced Sarcopenia in Patients Autopsied after Death from Colorectal Cancer

Cachexia frequently occurs in cancer patients and is correlated with reduced therapeutic responsiveness and poor prognosis. Although skeletal muscle atrophy is an important factor related to cachexia, biomarkers for its early diagnosis are not yet definitive. In this study, weight loss, body mass index, skeletal muscle index (SMI), serum carcinoembryonic antigen, serum tumor necrosis factor (TNF)-α, serum interleukin (IL)-6, serum high mobility group box (HMGB)-1, and SDS-soluble myosin light chain 1 (SDS-MYL1) of the psoas muscle were examined in 8 autopsied cases of death from colorectal cancer (CRC) as biomarkers of cachexia. SDS-MYL1 was positively correlated to SMI and TNF-α was negatively correlated, but the other factors did not show any correlations with SMI. Multivariate analysis showed that of the 3 cytokines, TNF-α and HMGB1 were correlated with SMI. Furthermore, when the biochemical skeletal muscle maturation marker, SDS-MYL1, was compared with serum cytokines, TNF-α and HMGB1 were negatively correlated but IL-6 was not. In multivariate analysis, only TNF-α was associated with SDS-MYL1. A positive correlation was found between TNF-α and HMGB1. These findings suggest that since TNF-α was inversely correlated with SMI and SDS-MYL1, TNF-α is a serum marker of skeletal muscle atrophy in CRC. Moreover, SDS-MYL1 might be established as a biomarker linked to clinical sarcopenia in experiments in vitro and in vivo.

Concurrent Expression of CD47 and CD44 in Colorectal Cancer Promotes Malignancy

CD47 activates signal regulatory protein alpha expressed on macrophages and suppresses its phagocytic ability; therefore, CD47 is drawing attention as an immune checkpoint in the innate immune system. Expression of CD47 in cancer is thought to allow cancer cells to escape antitumor immunity of the innate immune system. In this study, expression of CD47 was examined by immunostaining in colorectal cancer (CRC) and compared with the expression of CD44, which is a marker for cancer stem cells. In 95 cases of stage II-IV CRC, CD47 and CD44 showed overexpression in 82 and 80 cases, respectively. Both expression levels correlated with distant metastasis. Moreover, the expression of CD47 and CD44 in each case showed a significant correlation. In stage III cases, disease-free survival of cases showing high expression of CD47 and CD44 was worse than that of the cases with low expression. Furthermore, 3 of the stage IV cases were administered nivolumab, a checkpoint inhibitor of the acquired immune system, and 2 patients showed recurrence thereafter. All recurrent tumors highly expressed CD47 and CD44 and showed the epithelial-mesenchymal transition (EMT) phenotype. Our results suggest that CD47 promotes the malignancy of CRC in association with EMT and enhances the stemness of cancer cells. Moreover, our study suggests that CD47 and CD44 are involved in imparting resistance to programmed cell death (PD)-1/PD-ligand 1 inhibitors.

microRNAs-107 inhibited autophagy, proliferation, and migration of breast cancer cells by targeting HMGB1

PURPOSE

To investigate the effects of microRNAs-107 (miR-107) on autophagy, proliferation, and migration of breast cancer cells and its mechanism by targeting high mobility group protein B1 (HMGB1).

METHODS

Real-time polymerase chain reaction assay was used to detect the expression of miR-107 in breast cancer and its cell lines. In MDA-MB-231 and MDA-MB-453 breast cancer cells, the expression of p62, Beclin1 protein, and the changes of cell proliferation and migration after overexpression of m miR-107 were detected by Western blotting, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and transwell assays. Target Scan online prediction, dual luciferase reporter gene, and Western blot were used to verify the targeting relationship between miR-107 and HMGB1. The effects of silencing HMGB1 expression on p62, Beclin1 protein expression, cell proliferation, and migration ability were detected. The transfected MDA-MB-453 cells were inoculated into the right axilla of the nude mice, the tumor volume and weight were weighed, and the expression of miR-107, HMGB1, p62, and Beclin1 in the tumor were detected.

RESULTS

The expression of miR-107 was downregulated in breast cancer tissues and cell lines (P < 0.01). The expression of p62 protein was upregulated (P < 0.01), while Beclin1 protein was downregulated (P < 0.01) and cell proliferation and migration ability were decreased (P < 0.01) after overexpressing miR-107 in MDA-MB-231 and MDA-MB-453 cells. The results of TargetScan online prediction, dual luciferase reporter gene, and Western blot showed that miR-107 could regulate HMGB1 expression. The expression of p62 protein was upregulated (P < 0.01), while Beclin1 protein was downregulated (P < 0.01) and cell proliferation and migration ability were decreased (P < 0.01) after silencing HMGB1 in MDA-MB-231 and MDA-MB-453 cells. The results of xenograft experiments showed that miR-107 could delay tumor growth and inhibit autophagy.

CONCLUSION

miR-107 could inhibit cell autophagy, proliferation, and migration of breast cancer cells by targeting HMGB1.

HMGB1 protein as a novel target for cancer

Highly conserved nuclear protein High Mobility Group Box1 (HMGB1) present in mammals has functionality as an immuno-modulator in the form of cytokine molecule, as a nuclear factor to regulate these molecules and DNA structural determination. It has proximal homologous DNA binding domains Box-A, Box-B and distal C-terminal domain. Reduced form exists in basic condition has chemotaxis activity, while form with disulphide bond reduced at 106th cysteine showed cytokine activity. The oxidized form is devoid of both activities. HMGB1 binds and bends dsDNA and also activates genes for secretion of inflammatory cytokines such as IL-1β, TNF-α, IL-6 and IL-18. It can interact with transcription factors Rel/NF-κB and p53 responsible for up-regulating oncogenes. Oxidative stressed injured tissues actively secrete HMGB1 outside cells to necrotize other nearby tissues passively in cytosol. Acetylation of HMGB1 weakens its binding with DNA, and promotes its migration to different tissues leading to secretion of inflammatory-cytokines. HMGB1 expression has been found very important in the genesis and promotion of different cancer by promoting metastasis. In current article, we emphasized on condition based structural variability of HMGB1, mechanism of release, physiological functions and its functionality as a biomarker for cancer to be targeted to curb cancer genesis and progression.

The progression of HMGB1-induced autophagy in cancer biology

Autophagy is an important process of cellular degradation and has been proven to contribute to tumorigenesis. High-mobility group box 1 (HMGB1) is an abundant nonhistone protein that has been widely reported to play a central role in the induction of autophagy. In nucleus, HMGB1 upregulates the expression of HSP27 to induce autophagy. In cytoplasm, the Beclin-1/PI3K-III complex can be activated by HMGB1 to promote autophagy. Extracellular HMGB1 binds to the receptor for advanced glycation end products to induce autophagy. Recent studies have shown that HMGB1-induced autophagy exerts multiple functions in various cancers like proliferation. Moreover, inhibition of HMGB1-induced autophagy can reverse chemoresistance, which is regulated by noncoding RNAs such as microRNAs and lncRNAs. Here, we provide a brief introduction to HMGB1 and HMGB1-induced autophagy in cancer. We also discuss the challenges associated with performing further investigations on this issue. HMGB1-induced autophagy exerts significant functions in cancer and has potential utility for new strategy to reverse drug resistance.

The role of high-mobility group protein box 1 in lung cancer

High-mobility group protein box 1(HMGB1)is a ubiquitous highly conserved nuclear protein. Acting as a chromatin-binding factor, HMGB1 binds to DNA and plays an important role in stabilizing nucleosome formation, facilitating gene transcription, DNA repairing, inflammation, cell differentiation, and regulating the activity of steroid hormone receptors. Currently, HMGB1 is discovered to be related to development, progression, and targeted therapy of lung cancer, which makes it an attractive biomarker, and therapeutic target. This review aims to encapsulate the relationship between HMGB1 and lung cancer, suggesting that HMGB1 plays a pivotal role in initiation, development, invasion, metastasis, and prognosis of lung cancer.

Single Nucleotide Polymorphisms in HMGB1 Correlate with Lung Cancer Risk in the Northeast Chinese Han Population

Lung cancer is the principal cause of cancer-associated deaths. HMGB1 has been reported to be associated with tumorigenesis. This study aimed to investigate the relationship between rs1412125 and rs1360485 polymorphisms in HMGB1 and the risk and survival of lung cancer. 850 cases and 733 controls were included. Logistic regression analysis and survival analysis were performed to investigate the association between SNPs and the risk and survival of lung cancer. Crossover analysis was used to analyze the interaction between SNPs and tobacco exposure. Results indicated that rs1412125 polymorphism was associated with lung cancer risk, especially with the risk of lung adenocarcinoma and small cell lung cancer. Carriers with CT and CC genotypes had a decreased risk of lung cancer (CT + CC vs.TT: adjusted OR = 0.736, p = 0.004). Similar results were obtained in the stratification analysis for non-smokers and female population. For rs1360485 polymorphism, AG and GG genotypes could decrease the risk of lung adenocarcinoma and female lung cancer by 0.771-fold and 0.789-fold. However, no significant interaction between polymorphisms and tobacco exposure or association between SNPs and the survival of lung cancer was observed. This study indicated polymorphisms in HMGB1 may be a novel biomarker for female lung adenocarcinoma risk.

The function and mechanism of HMGB1 in lung cancer and its potential therapeutic implications

As a non-histone chromatin-associated protein, high-mobility group box-1 (HMGB1) performs a pivotal function in various human diseases, including autoimmune diseases, neurodegenerative diseases and cancer. Overexpression of HMGB1 has been demonstrated in numerous types of cancer, including breast cancer, colorectal cancer, lung cancer and hepatocellular carcinoma. However, the underlying mechanism of HMGB1 function in lung cancer remains to be elucidated. The present study aimed to analyze, and summarize the role and mechanism of HMGB1 in lung cancer by retrieving available literature regarding HMGB1 in association with lung cancer. It provides comprehensive information on the association of HMGB1 with the carcinogenesis and progression of lung cancer, and discusses the molecular mechanism of these processes. HMGB1 may induce tumorigenesis, metastasis and chemotherapy resistance in lung cancer. Overall, it is evident that HMGB1 serves an important role in the development and progression of lung cancer, and this review warrants further investigation into HMGB1 as a novel target for cancer therapy.

Matrine Ameliorates Colorectal Cancer in Rats via Inhibition of HMGB1 Signaling and Downregulation of IL-6, TNF-α, and HMGB1

Matrine may be protective against colorectal cancer (CRC), but how it may work is unclear. Thus, we explored the underlying mechanisms of matrine in CRC. Matrine-related proteins and CRC-related genes and therapeutic targets of matrine in CRC were predicted using a network pharmacology approach. Five targets, including interleukin 6 (IL-6), the 26S proteasome, tumor necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1) and p53, and corresponding high-mobility group box 1 (HMGB1) signaling and T helper cell differentiation were thought to be associated with matrine's mechanism. Expression of predicted serum targets were verified in a 1,2-dimethylhydrazine dihydrochloride-induced CRC model rats that were treated with matrine (ip) for 18 weeks. Data show that matrine suppressed CRC growth and decreased previously elevated expression of IL-6, TNF-α, p53, and HMGB1. Matrine may have had a therapeutic effect on CRC via inhibition of HMGB1 signaling, and this occurred through downregulation of IL-6, TNF-α, and HMGB1.

HMGB1 genetic polymorphisms are biomarkers for the development and progression of breast cancer

Breast cancer is a major cause of cancer mortality worldwide. High-mobility group box protein 1 (HMGB1) is a ubiquitous nuclear protein found in all mammal eukaryotic cells that participates in tumor progression, migration and metastasis. HMGB1 overexpression has been indicated in breast cancer patients. However, scant information is available regarding the association between HMGB1 single nucleotide polymorphisms (SNPs) and the risk or prognosis of breast cancer. We report on the association between 4 SNPs of the HMGB1 gene (rs1360485, rs1045411, rs2249825 and rs1412125) and breast cancer susceptibility as well as clinical outcomes in 313 patients with breast cancer and in 217 healthy controls. Patients with one G allele in the rs1360485 or rs2249825 domains are likely to progress to T2 tumor and lymph node metastasis. In addition, the presence of one G allele in SNPs rs1360485 or rs2249825 was associated with a higher risk of progressing to T2 tumor and distant metastasis amongst HER2-enriched and triple-negative breast cancer (TNBC) tumors compared with luminal A and luminal B tumors. Furthermore, having one C allele in the rs1412125 domain increased the risk of pathologic grade 3 disease in HER2-enriched and TNBC tumors. Our results indicate that genetic variations in the HMGB1 gene may serve as an important predictor of breast cancer progression and metastasis.

HMGB1-induced angiogenesis in perforated disc cells of human temporomandibular joint

High mobility group 1 protein (HMGB1), a highly conserved nuclear DNA‐binding protein and inflammatory mediator, has been recently found to be involved in angiogenesis. Our previous study has demonstrated the elevation of HMGB1 in the tissue of perforated disc of temporomandibular joint (TMJ). Here, we investigated a novel mediator of HMGB1 in regulating hypoxia‐inducible factor‐1α (HIF‐1α) and vascular endothelial growth factor (VEGF) to mediate angiogenesis in perforated disc cells of TMJ. HMGB1 increased the expression of HIF‐1α and VEGF in a dose‐ and time‐dependent manner in these cells. Moreover, immunofluorescence assay exhibits that the HIF‐1α were activated by HMGB1. In addition, HMGB1 activated extracellular signal‐related kinase 1/2 (Erk1/2), Jun N‐terminal kinase (JNK), but not P38 in these cells. Furthermore, both U0126 (ErK inhibitor) and SP600125 (JNK inhibitor) significantly suppressed the enhanced production of HIF‐1α and VEGF induced by HMGB1. Tube formation of human umbilical vein endothelial cells (HUVECs) was significantly increased by exposure to conditioned medium derived from HMGB1‐stimulated perforated disc cells, while attenuated with pre‐treatment of inhibitors for VEGF, HIF‐1α, Erk and JNK, individually. Therefore, abundance of HMGB1 mediates activation of HIF‐1α in disc cells via Erk and JNK pathway and then, initiates VEGF secretion, thereby leading to disc angiogenesis and accelerating degenerative change of the perforated disc.

Expression levels and clinical significance of hepsin and HMGB1 proteins in cervical carcinoma

This study assessed the hypothesis that the protein levels of high mobility group box 1 (HMGB1) and hepsin can be used as markers for diagnosis and prognosis in cervical carcinoma. Seventy patients with cervical cancer who were hospitalized in Xuzhou Central Hospital from May 2008 to June 2010 and underwent surgical treatment were selected for the observation group. At the same time, 20 patients with cervical benign lesions who underwent tumor stripping or accessory resection were selected for the control group. Immunohistochemical (SP) detection methods were used to detect hepsin and HMGB1 protein levels in tissues. The positive rates of HMGB1 cells in normal, paracancerous and cancerous cervical tissues were 5.0% (1/20), 22.9% (16/70) and 95.7% (67/70) (F=24.581, P=0.001) respectively. The positive rates of hepsin in normal, paracancerous and cancerous cervical tissues were respectively 10% (2/20), 61% (43/70) and 90% (63/70) (F=11.538, P=0.001). The HMGB1 expression level was related to the degree of tumor differentiation, lymph node metastasis and TNM stage (P<0.05). While the level of hepsin expression was related to the degree of tumor differentiation, invasion depth, lymph node metastasis and TNM stage (P<0.05). Furthermore, a positive correlation between the levels of hepsin and HMGB1 was found (r=15.27, P<0.05). The overall 5-year survival rates of patients with high expression of HMGB1 (+++) and low expression of HMGB1 (+ to ++) were respectively 51.2 and 29.2% (HR=11.637, 95% CI=4.351-38.213; P=0.002). The overall 5-year survival rates of patients with high hepsin expression (+++) and low hepsin expression (+ to ++) were respectively 41.3 and 35.3% (HR=10.143, 95% CI=4.285-33.275; P=0.006). Based on our results, the higher the levels of expression of hepsin and HMGB1 in tissues the higher the degree of invasiveness of the cervical cancers, and the worse the prognoses for the patient.

The dual role and therapeutic potential of high-mobility group box 1 in cancer

High-mobility group box 1 (HMGB1) is an abundant protein in most eukaryocytes. It can bind to several receptors such as advanced glycation end products (RAGE) and Toll-like receptors (TLRs), in direct or indirect way. The biological effects of HMGB1 depend on its expression and subcellular location. Inside the nucleus, HMGB1 is engaged in many DNA events such as DNA repair, transcription, telomere maintenance, and genome stability. While outside the nucleus, it possesses more complicated functions, including regulating cell proliferation, autophagy, inflammation and immunity. During tumor development, HMGB1 has been characterized as both a pro- and anti-tumoral protein by either promoting or suppressing tumor growth, proliferation, angiogenesis, invasion and metastasis. However, the current knowledge concerning the positive and negative effects of HMGB1 on tumor development is not explicit. Here, we evaluate the role of HMGB1 in tumor development and attempt to reconcile the dual effects of HMGB1 in carcinogenesis. Furthermore, we would like to present current strategies targeting against HMGB1, its receptor or release, which have shown potentially therapeutic value in cancer intervention.

High ASMA+ Fibroblasts and Low Cytoplasmic HMGB1+ Breast Cancer Cells Predict Poor Prognosis

INTRODUCTION

The influence of cancer-associated fibroblasts (CAFs) and high mobility group box 1 (HMGB1) has been recognized in several cancers, although their roles in breast cancer are unclear. The present study aimed to determine the levels and prognostic significance of α-smooth muscle actin-positive (ASMA⁺) CAFs, plus HMGB1 and receptor for advanced glycation end products (RAGE) in cancer cells.

MATERIALS AND METHODS

A total of 127 breast samples, including 96 malignant and 31 benign, were examined for ASMA, HMGB1, and RAGE by immunohistochemistry. The χ² test and Fisher's exact test were used to test the association of each protein with clinicopathologic parameters. The Kaplan-Meier method or log-rank test and Cox regression were used for survival analysis.

RESULTS

ASMA⁺ fibroblast infiltration was significantly increased in the tumor stroma compared with that in benign breast tissue. The levels of cytoplasmic HMGB1 and RAGE were significantly greater in the breast cancer tissue than in the benign breast tissues. High ASMA expression correlated significantly with large tumor size, clinical stage III-IV, and angiolymphatic and perinodal invasion. In contrast, increased cytoplasmic HMGB1 correlated significantly with small tumor size, pT stage, early clinical stage, luminal subtype (but not triple-negative subtype), and estrogen receptor and progesterone receptor expression. The levels of ASMA (hazard ratio, 14.162; P = .010) and tumor cytoplasmic HMGB1 (hazard ratio, 0.221; P = .005) could serve as independent prognostic markers for metastatic relapse in breast cancer patients. The ASMA-high/HMGB1-low profile provided the most reliable prediction of metastatic relapse.

CONCLUSION

We present for the first time, to the best of our knowledge, the potential clinical implications of the combined assessment of ASMA⁺ fibroblasts and cytoplasmic HMGB1 in breast cancer.

Paradoxical Role of High Mobility Group Box 1 in Glioma: A Suppressor or a Promoter?

Gliomas represent 60% of primary intracranial brain tumors and 80% of all malignant types, with highest morbidity and mortality worldwide. Although glioma has been extensively studied, the molecular mechanisms underlying its pathology remain poorly understood. Clarification of the molecular mechanisms involved in their development and/or treatment resistance is highly required. High mobility group box 1 protein (HMGB1) is a nuclear protein that can also act as an extracellular trigger of inflammation, proliferation and migration, through receptor for advanced glycation end products and toll like receptors in a number of cancers including gliomas. It is known that excessive release of HMGB1 in cancer leads to unlimited replicative potential, ability to develop blood vessels (angiogenesis), evasion of programmed cell death (apoptosis), self-sufficiency in growth signals, insensitivity to inhibitors of growth, inflammation, tissue invasion and metastasis. In this review we explore the mechanisms by which HMGB1 regulates apoptosis and autophagy in glioma. We also looked at how HMGB1 mediates glioma regression and promotes angiogenesis as well as possible signaling pathways with an attempt to provide potential therapeutic targets for the treatment of glioma.

New frontiers in the treatment of colorectal cancer: Autophagy and the unfolded protein response as promising targets

Colorectal cancer (CRC), despite numerous therapeutic and screening attempts, still remains a major life-threatening malignancy. CRC etiology entails both genetic and environmental factors. Macroautophagy/autophagy and the unfolded protein response (UPR) are fundamental mechanisms involved in the regulation of cellular responses to environmental and genetic stresses. Both pathways are interconnected and regulate cellular responses to apoptotic stimuli. In this review, we address the epidemiology and risk factors of CRC, including genetic mutations leading to the occurrence of the disease. Next, we discuss mutations of genes related to autophagy and the UPR in CRC. Then, we discuss how autophagy and the UPR are involved in the regulation of CRC and how they associate with obesity and inflammatory responses in CRC. Finally, we provide perspectives for the modulation of autophagy and the UPR as new therapeutic options for CRC treatment.

Association of HMGB1 Gene Polymorphisms with Lung Cancer Susceptibility and Clinical Aspects

Lung cancer is one of the most frequently diagnosed malignancies and is associated with a poor survival rate in the Chinese Han population. Analysis of genetic variants could lead to improvements in prognosis following lung cancer therapy. High-mobility group box 1 protein (HMGB1) is a ubiquitous nuclear protein found in eukaryotic cells that participates in several biological functions including immune response, cell survival, apoptosis and cancer development. We investigated the effects of HMGB1 gene polymorphisms on the risk of lung cancer progression in a Chinese Han population. Our sample of 751 participants included 372 patients with lung cancer and 379 healthy controls. Four single-nucleotide polymorphisms (SNPs) of the HMGB1 gene were examined by real-time polymerase chain reaction (RT-PCR). We found that the CT or CC+CT heterozygotes of the HMGB1 rs1045411 polymorphism reduced the risks for lung cancer, while the G/T/C haplotypes of three HMGB1 SNPs (rs1360485, rs1045411 and rs2249825) also reduced the risk for lung cancer by almost half (0.486-fold). The current study is the first to examine the risk factors associated with HMGB1 SNPs in lung cancer development in the Chinese Han population.

Inhibiting the cytoplasmic location of HMGB1 reverses cisplatin resistance in human cervical cancer cells

Cervical cancer is the fourth most common malignancy in women worldwide, and resistance to chemotherapy drugs is the biggest obstacle in the treatment of cervical cancers. In the present study, the molecular mechanisms underlying cisplatin resistance in human cervical cancer cells were investigated. When human cervical cancer cells were treated with 10 µg/ml of cisplatin for 24 and 48 h, high mobility group box 1 (HMGB1) protein expression levels significantly increased in a time‑dependent manner. Comparisons between cisplatin‑sensitive HeLa cells and cisplatin‑resistant HeLa/DDP cells revealed higher levels of HMGB1 in HeLa/DDP cells than in HeLa cells. Additionally, the half maximal inhibitory concentration (IC50) value for cisplatin in HeLa/DDP cells was 5.3‑fold that in HeLa cells. Analysis of the distribution of cellular components revealed that HMGB1 translocation from the nucleus to cytoplasm contributed to cisplatin resistance. This was further confirmed by demonstration that ethyl pyruvate treatment suppressed the cytoplasmic translocation of HMGB1, resulting in inhibition of HeLa cell proliferation. Furthermore, endogenous HMGB1 was inhibited with HMGB1‑specific short hairpin (sh)RNA, and MTT assay results showed that interference with HMGB1 expression reduced cell viability and potentially reversed cisplatin resistance in HeLa cells. Transfection with HMGB1 shRNA was demonstrated to induce cell apoptosis in HeLa cells, as detected by FACS analysis. In addition, administration of recombinant HMGB1 protein in HeLa cells promoted cell autophagy, mediated by the phosphorylation of extracellular signal‑regulated kinase 1/2. Thus, cytoplasmic HMGB1 translocation and HMGB1‑induced cell autophagy are proposed to contribute to cisplatin resistance by inhibiting apoptosis of cervical cancer cells. HMGB1 could, therefore, represent a novel therapeutic target for, and a diagnostic marker of, chemotherapy resistant cervical cancers.

Association of HMGB1 Gene Polymorphisms with Risk of Colorectal Cancer in a Chinese Population

Background

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. More advanced work is required in the detection of biomarkers for CRC susceptibility and prognosis. High-mobility group box-1 (HMGB1) is an angiogenesis-related gene reported to be associated with the development of CRC. The direct evidence of HMGB1 gene polymorphisms as biomarkers for CRC has not been reported previously.

Material/Methods

A total of 240 CRC patients and 480 healthy controls were periodically enrolled. DNA was extracted from blood specimens. The distributions of SNPs of HMGB1 were determined by using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay.

Results

In this case-control study, we observed a significant association between overall CRC risk and SNP rs2249825 (CG vs. CC and GG vs. CC). Participants carrying both rs2249825 CG (OR, 2.67; 95% CI, 1.89 to 3.78) and rs2249825 GG genotypes (OR, 2.32; 95% CI, 1.13 to 4.73) had a significantly increased risk of developing CRC compared to those carrying GG genotype. rs2249825 was associated with the risk of CRC in the dominant model but not in the recessive model. However, we found no significant differences in the rs1412125 or rs1045411 polymorphisms in the HMGB1. Advanced analyses showed that the number of rs2249825 G alleles showed a significant relationship with risk of CRC.

Conclusions

Our results show an association between HMGB1 rs2249825 SNP and CRC incidence in the Chinese Han population. However, population-based studies with more subjects and prognostic effects are needed to verify the association of HMGB1 SNPs with CRC susceptibility, severity, and long-term prognosis.

The association of HMGB1 expression with clinicopathological significance and prognosis in Asian patients with colorectal carcinoma: a meta-analysis and literature review

Background

The association of high mobility group box 1 (HMGB1) expression with clinicopathological significance and prognosis in Asian patients with colorectal carcinoma (CRC) remains controversial. The purpose of this study was to conduct a meta-analysis and literature review to identify the role of HMGB1 in the development and prognosis of CRC in Asians.

Methods

All eligible studies regarding the association between HMGB1 expression in tissue with clinicopathological significance and prognosis in Asian patients with CRC published up to January 2015 were identified by searching PubMed, Web of Science, Chinese National Knowledge Infrastructure, and WanFang database. Analysis of pooled data was performed, while odds ratio (OR) or hazard radio with 95% confidence interval (CI) was calculated and summarized to evaluate the strength of this association in fixed- or random-effects model.

Results

The expression level of HMGB1 in CRC tissues was much higher than normal colorectal tissues (OR =27.35, 95% CI 9.32–80.26, P<0.0001) and para-tumor colorectal tissues (OR =10.06, 95% CI 4.61–21.95, P<0.0001). There was no relation between the HMGB1 expression and sex, age, clinical T stage, tumor size, and location (colon or rectum cancer). However, a significant relation was detected between the HMGB1 expression and clinical stage (American Joint Committee on Cancer 7), lymph node metastasis, distant metastasis, tumor invasion depth, and differentiation rate (P=0.002, P≤0.0001, P<0.0001, P<0.0001, and P=0.007, respectively). Patients with higher HMGB1 expression had shorter overall survival time, whereas patients with lower level of HMGB1 had better survival (hazard ratio =1.40, 95% CI 0.98–1.82, P<0.0001).

Conclusion

In this meta-analysis, our results illustrated the significant relationship of HMGB1 protein overexpression in tissues with clinicopathological characteristics and prognosis of CRC. Thus, HMGB1 may be a promising marker in predicting the clinical outcome of patients with CRC. However, more well-designed studies of large sample size are warranted to validate the findings of current study.

HMGB1 knockdown effectively inhibits the progression of rectal cancer by suppressing HMGB1 expression and promoting apoptosis of rectal cancer cells

Rectal cancer is a malignant gastrointestinal tumor, which is associated with high morbidity and mortality. High‑mobility group protein 1 (HMGB1) is widely present in the nucleus of eukaryotic cells, and is highly conserved between humans and rodents. Recently, HMGB1 has been reported to be involved in the progression and metastasis of human cancer; however, its role in the development and metastasis of human rectal cancer remains unclear. The present study detected the expression levels of HMGB1 in pathological specimens from patients with clinically identified rectal cancer using immunohistochemistry and western blotting. The results demonstrated that HMGB1 was highly expressed in samples from patients with rectal cancer. The positive rate of HMGB1 in rectal cancer tissues was 96.08% (49/51), which was significantly higher compared with 3.92% (2/51) in normal tissues. In addition, western blotting indicated that HMGB1 was distributed and located not only in the nucleus, but also in the cytoplasm of colorectal cancer cells. HMGB1‑specific short hairpin (sh)RNA was used to silence the endogenous expression of HMGB1 in colorectal cancer cells. A functional assay demonstrated that knockdown of endogenous HMGB1 expression significantly inhibited the proliferation of SW620 and Colo320 cells. Furthermore, western blotting revealed that knockdown of endogenous HMGB1 expression contributed to activation of caspase‑3 and the substrate poly (ADP‑ribose) polymerase. The expression levels of B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein (Bax) were also detected by western blotting. As expected, decreased levels of Bcl‑2 and increased levels of Bax were detected in the HMGB1 shRNA‑transfected colorectal cancer cells, and the Bax/Bcl‑2 ratio was increased in HMGB1 shRNA‑transfected cells. These data indicated that HMGB1 may act as an oncogene in rectal cancer, and knockdown of endogenous HMGB1 expression may significantly inhibit the proliferation of colorectal cancer cells and promote apoptosis of tumor cells. Further research regarding the mechanisms underlying the effects of HMGB1 on the progression of rectal cancer may provide novel targets for the treatment of rectal cancer, and provide a theoretical reference for clinical treatment.

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.

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.

Effects of HMGB1 Polymorphisms on the Susceptibility and Progression of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignancy of liver and a leading cause of cancer mortality worldwide. Its management is compounded by biological and clinical heterogeneity. These interindividual genetic variations can modulate the effects of HCC treatment. High-mobility group box protein 1 (HMGB1) is a well investigated, ubiquitous nuclear protein found in eukaryotic cells that plays a multiple biological roles such as DNA stability, program cell death, immune response, and furthermore in cancer progression. In this report, we examined HMGB1 single nucleotide polymorphisms (SNPs) with multiple risk factors related to HCC susceptibility and clinicopathological characteristics. Four HMGB1 SNPs (rs1412125, rs2249825, rs1045411, and rs1360485) were assessed by using a TaqMan SNPs Genotyping in 324 patients with HCC and in 695 cancer-free controls. The results showed that HMGB1 SNP rs1045411 with CT or at least one T alleles has lower risk of HCC than wild-type (CC) carriers. Moreover, HMGB1 SNP rs1412125 with TT allele has a higher risk of distant metastasis compared with patients carrying at least one C allele. The present study is the first report to discuss the risk factors associated with HMGB1 SNPs in HCC progression in Taiwan.

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.

The microRNA-325 inhibits hepatocellular carcinoma progression by targeting high mobility group box 1

Background

MicroRNAs (miRNAs) can serve as tumor suppressors and might provide an efficient strategy for annihilating tumor cells. Nevertheless, the potential role of miR-325 in hepatocellular carcinoma (HCC) is still unknown.

Methods

Using RT-PCR, immunoblots invasion assays and bioinformatics strategies, we investigated the potential role of miR-325 in HCC.

Results

We showed that miR-325 was decreased and HMGB1 was increased in 99 patients with hepatocellular carcinoma. MiR-325 inhibition promoted cell invasion and proliferation, while miR-325 upregulation inhibited cell invasion and proliferation by using transwell and CCK8 assays. We further showed that HMGB1 might be a direct target of miR-325 and is negatively regulated by miR-325. Down-regulation of miR-325 predicts poor prognosis for HCC patients.

Conclusions

These findings implied that miR-325 regulates cell invasion and proliferation via targeting HMGB1 and may be a potential prognostic marker for HCC.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4655707031717989

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.

High mobility group protein B1: a new biomarker of obesity in pregnant women?

Obesity is associated with an increased risk of an adverse pregnancy outcome. The aim of this study was to analyze the serum levels of high mobility group protein B1 (HMGB1) in obese pregnant women, to assess the role of this protein in the pathogenesis of this disease and to evaluate its possible function as a diagnostic marker for obesity-related complications in obese women. Study participants were randomly selected, from a cohort of pregnant women afferent to our department. A total of 120 women were enrolled in this study: 60 pregnant women had normal body mass index (BMI) and 60 women resulted obese. Pre-pregnancy BMI, weight increase and HMGB1 levels were evaluated for each pregnant woman enrolled. Matching serum HMGB1 levels in two groups, our data evidenced higher levels in the obese women, with a statistically significant difference (p = 0.0023). A significant positive univariate correlation was observed between serum HMGB1 levels and BMI in obese women. HMGB1 serum levels may therefore represent a predictive marker of disease in pregnant women (r = 20.9 and p = 0.0001). Further studies are needed in order to validate the role of this cytokine, with the aim of making it possible to use in clinical practice not only for diagnostic purposes, but especially for the early recognition of complications related to it.

Expression of MicroRNA-325-3p and its potential functions by targeting HMGB1 in non-small cell lung cancer

MicroRNAs (miRNAs) can function as tumor suppressors and might provide an efficient strategy for annihilating cancer. Nevertheless, the potential role of miR-325-3p in NSCLC is still unknown. Here, we showed that miR-325-3p was decreased and HMGB1 was increased in 107 NSCLC patients. MiR-325-3p inhibition promoted cell invasion and proliferation, while miR-325-3p upregulation inhibited cell invasion and proliferation by using transwell and CCK8 assays. Using a bioinformatics method, we further showed that HMGB1 might be a direct target of miR-325-3p and is negatively regulated by miR-325-3p. Down-regulation of miR-325-3p predicts poor prognosis for NSCLC patients. These findings implied that miR-325-3p regulates cell invasion and proliferation via targeting HMGB1 and may be a potential prognostic marker for NSCLC.

Association of Upregulated HMGB1 and c-IAP2 Proteins With Hepatocellular Carcinoma Development and Progression

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most important health problems in China.

OBJECTIVES

This study analyzed expression of high-mobility group protein B1 (HMGB1) and inhibitor of apoptosis protein-2 (c-IAP2) proteins in HCC compared to paired para-tumor tissue samples to assess the association with HCC pathogenesis and progression.

MATERIALS AND METHODS

Sixty-eight HCC and para-tumor tissue samples were collected for Western blot, qRT-PCR and immunohistochemical analyses of HMGB1 and c-IAP2.

RESULTS

HMGB1 and c-IAP2 proteins were highly expressed in HCC tissue samples [85.3% (58/68) and 82.4% (56/68), respectively] compared to para-tumor tissue samples [32.3% and 27.9%, respectively]. Furthermore, expression of HMGB1 was significantly associated with enhanced c-IAP2 expression in HCC tissue samples (r = 0.878, P < 0.01). Expression of HMGB1 was associated with tumor multiplicity and size, alpha-fetoprotein (AFP) level and advanced TNM stage, while expression of c-IAP2 was associated with tumor size, AFP level and advanced TNM stage.

CONCLUSIONS

Expression of HMGB1 and c-IAP2 proteins was associated with HCC development and progression, and the expression of HMGB1 and c-IAP2 proteins in HCC were significantly associated with each other. Additionally, these proteins may show promise as biomarkers to predict HCC progression.

Clinical and prognostic significance of high-mobility group box-1 in human gliomas

The objective of this study was to explore the expression and the clinical and prognostic significance of high-mobility group box-1 (HMGB1) in human gliomas. The expression of HMGB1 in 15 samples of normal brain tissue and 65 samples of different-grade glioma tissue was assayed using immunohistochemistry and western blot analysis. The associations between the differences in expression and pathology grades were analyzed statistically. Uni- and multivariate analyses were performed to investigate the prognostic value of HMGB1 expression and its expression levels. The positive rates of HMGB1 expression in normal brain and glioma tissue were 20.0% (3/15) and 76.9% (50/65), respectively. The expression of HMGB1 in glioma tissue was higher than that in normal tissue (P<0.05). The positive rates of HMGB1 expression in low-grade gliomas (LGGs, grades I and II) and high-grade gliomas (HGGs, grades III and IV) were 63.0% (17/27) and 86.8% (33/38), respectively, and the positive rates in HGG were higher than those in LGG (P=0.024). Western blot analysis showed that HMGB1 was also expressed in normal brain tissue. The expression levels in HGG were significantly higher than those in LGG (P<0.001). HMGB1-positive patients had significantly shorter overall survival times compared with HMGB1-negative patients (P=0.026). Increasing levels of HMGB1 expression significantly correlated with reduced survival times when all patients with glioma were considered (P=0.045). In conclusion, HMGB1 positivity and protein expression levels are of significant clinical and prognostic value in human gliomas. Detecting HMGB1 in human gliomas may be useful for assessing the degree of malignancy, and HMGB1 would appear to be a promising target in the clinical management of patients with glioma.

Cancer usurps skeletal muscle as an energy repository

Cancer cells produce energy through aerobic glycolysis, but contributions of host tissues to cancer energy metabolism are unclear. In this study, we aimed to elucidate the cancer-host energy production relationship, in particular, between cancer energy production and host muscle. During the development and progression of colorectal cancer, expression of the secreted autophagy-inducing stress protein HMGB1 increased in the muscle of tumor-bearing animals. This effect was associated with decreased expression of pyruvate kinase PKM1 and pyruvate kinase activity in muscle via the HMGB1 receptor for advanced glycation endproducts (RAGE). However, muscle mitochondrial energy production was maintained. In contrast, HMGB1 addition to colorectal cancer cells increased lactate fermentation. In the muscle, HMGB1 addition induced autophagy by decreasing levels of active mTOR and increasing autophagy-associated proteins, plasma glutamate, and (13)C-glutamine incorporation into acetyl-CoA. In a mouse model of colon carcinogenesis, a temporal increase in HMGB1 occurred in serum and colonic mucosa with an increase in autophagy associated with altered plasma free amino acid levels, increased glutamine, and decreased PKM1 levels. These differences were abolished by administration of an HMGB1 neutralizing antibody. Similar results were obtained in a mouse xenograft model of human colorectal cancer. Taken together, our findings suggest that HMGB1 released during tumorigenesis recruits muscle to supply glutamine to cancer cells as an energy source.

Inflammation triggers high mobility group box 1 (HMGB1) secretion in adipose tissue, a potential link to obesity

BACKGROUND

Low grade inflammation is one of the major metabolic disorders in case of obesity due to variable secretion of adipose derived cytokines called adipokines. Recently the nuclear protein HMGB1 was identified as an inflammatory alarmin in obesity associated diseases. However HMGB1 role in adipose tissue inflammation is not yet studied.

OBJECTIVES

The aim of this study was to prove the expression of HMGB1 in human adipose tissue and to assess the levels of expression between normo-weight and obese individuals. Furthermore we determined which type of cells within adipose tissue is involved in HMGB1 production under inflammatory signal.

METHODS

Western-blot was performed on protein lysates from human normo-weight and obese adipose tissue to study the differential HMGB1 expression. Human normo-weight adipose tissue, adipose-derived stromal cells (ASCs) and adipocytes were cultured and stimulated with LPS to induce inflammation. HMGB1, IL-6 and MCP-1 secretion and gene expression were quantified by ELISA and Q-PCR respectively, as well as cell death by LDH assay. HMGB1 translocation during inflammation was tracked down by immunofluorescence in ASCs.

RESULTS

HMGB1 was expressed 2-fold more in adipose tissue from obese compared to normo-weight individuals. LPS led to an up-regulation in HMGB1 secretion and gene expression in ASCs, while no change was noticed in adipocytes. Moreover, this HMGB1 release was not attributable to any cell death. In LPS-stimulated ASCs, HMGB1 translocation from nucleus to cytoplasm was detectable at 12h and the nuclear HMGB1 was completely drained out after 24h of treatment.

CONCLUSION

The expression level studies between adipose tissue from normo-weight and obese individuals together with in vitro results strongly suggest that adipose tissue secretes HMGB1 in response to inflammatory signals which characterized obesity.

Double-positive expression of high-mobility group box 1 and vascular endothelial growth factor C indicates a poorer prognosis in gastric cancer patients

Background

Although many studies have indicated that high-mobility group box 1 protein (HMGB1) is associated with oncogenesis and a worse prognosis, the prognostic value of HMGB1 in gastric cancer (GC) remains unclear. In the present work, we aimed to evaluate the role of HMGB1 in GC and examined whether aberrant expression of both HMGB1 and vascular endothelial growth factor C (VEGF-C) increased the malignant potential of GC.

Methods

A total of 166 GC patients and 32 normal subjects were enrolled. HMGB1 and VEGF-C expression was detected by tissue microarrays (TMAs) and immunohistochemical staining. The correlation between HMGB1 and VEGF-C expression and their relationships with clinicopathological GC variables were examined. Univariate and multivariate analyses were performed using the Cox proportional hazard model to predict the factors related to the patients‘ overall survival rates.

Results

HMGB1 and VEGF-C expression were observed in 81 (48.80%) and 88 (53.01%) tumors, respectively, significantly higher than the rates among the corresponding controls. In addition, HMGB1 and VEGF-C expression were positively correlated (R² = 0.972). HMGB1 expression was also closely associated with tumor size, pT stage, nodal status, metastasis status, TNM stage, and poor prognosis. Multivariate survival analysis indicated that patients with HMGB1 and VEGF-C coexpression had the worst prognoses and survival rates (hazard ratio, 2.78; log rank P<0.001).

Conclusions

HMGB1 is commonly expressed in GC. Combined evaluation of HMGB1 and VEGF-C may serve as a valuable independent prognostic factor for GC patients.