High Mobility Group Box 1 (HMGB1) Predicts Invasion and Poor Prognosis of Glioblastoma Multiforme via Activating AKT Signaling in an Autocrine Pathway

Impact of HMGB1 on cancer development and therapeutic insights focused on CNS malignancy

The present study explores the complex roles of High Mobility Group Box 1 (HMGB1) in the context of cancer development, emphasizing glioblastoma (GBM) and other central nervous system (CNS) cancers. HMGB1, primarily known for its involvement in inflammation and angiogenesis, emerges as a multifaceted player in the tumorigenesis of GBM. The overexpression of HMGB1 correlates with glioma malignancy, influencing key pathways like RAGE/MEK/ERK and RAGE/Rac1. Additionally, HMGB1 secretion is linked to the maintenance of glioma stem cells (GSCs) and contributes to the tumor microenvironment's (TME) vascular leakiness. Henceforth, our review discusses the bidirectional impact of HMGB1, acting as both a promoter of tumor progression and a mediator of anti-tumor immune responses. Notably, HMGB1 exhibits tumor-suppressive roles by inducing apoptosis, limiting cellular proliferation, and enhancing the sensitivity of GBM to therapeutic interventions. This dualistic nature of HMGB1 calls for a nuanced understanding of its implications in GBM pathogenesis, offering potential avenues for more effective and personalized treatment strategies. The findings underscore the need to explore HMGB1 as a prognostic marker, therapeutic target, and a promising tool for stimulating anti-tumor immunity in GBM.

GBM Immunotherapy: Macrophage Impacts

BACKGROUND

Glioblastoma (GBM) is an extremely aggressive form of brain tumor with low survival rates. Current treatments such as chemotherapy, radiation, and surgery are problematic due to tumor growth, invasion, and tumor microenvironment. GBM cells are resistant to these standard treatments, and the heterogeneity of the tumor makes it difficult to find a universal approach. Progression of GBM and acquisition of resistance to therapy are due to the complex interplay between tumor cells and the TME. A significant portion of the TME consists of an inflammatory infiltrate, with microglia and macrophages being the predominant cells.

METHODS

Analysis of the literature data over a course of 5 years suggest that the tumor-associated macrophages (TAMs) are capable of releasing cytokines and growth factors that promote tumor proliferation, survival, and metastasis while inhibiting immune cell function at the same time.

RESULTS

Thus, immunosuppressive state, provided with this intensively studied kind of TME cells, is supposed to promote GBM development through TAMs modulation of tumor treatment-resistance and aggressiveness. Therefore, TAMs are an attractive therapeutic target in the treatment of glioblastoma.

CONCLUSION

This review provides a comprehensive overview of the latest research on the nature of TAMs and the development of therapeutic strategies targeting TAMs, focusing on the variety of macrophage properties, being modulated, as well as molecular targets.

Crosstalk between glioblastoma and tumor microenvironment drives proneural-mesenchymal transition through ligand-receptor interactions

Glioblastoma (GBM) is the most common intrinsic and aggressive primary brain tumor in adults, with a median survival of approximately 15 months. GBM heterogeneity is considered responsible for the treatment resistance and unfavorable prognosis. Proneural-mesenchymal transition (PMT) represents GBM malignant progression and recurrence, which might be a breakthrough to understand GBM heterogeneity and overcome treatment resistance. PMT is a complicated process influenced by crosstalk between GBM and tumor microenvironment, depending on intricate ligand-receptor interactions. In this review, we summarize the autocrine and paracrine pathways in the GBM microenvironment and related ligand-receptor interactions inducing PMT. We also discuss the current therapies targeting the PMT-related autocrine and paracrine pathways. Together, this review offers a comprehensive understanding of the failure of GBM-targeted therapy and ideas for future tendencies of GBM treatment.

Cytokine Profile in Development of Glioblastoma in Relation to Healthy Individuals

Cytokines play an essential role in the control of tumor cell development and multiplication. However, the available literature provides ambiguous data on the involvement of these proteins in the formation and progression of glioblastoma (GBM). This study was designed to evaluate the inflammatory profile and to investigate its potential for the identification of molecular signatures specific to GBM. Fifty patients aged 66.0 ± 10.56 years with newly diagnosed high-grade gliomas and 40 healthy individuals aged 71.7 ± 4.9 years were included in the study. White blood cells were found to fall within the referential ranges and were significantly higher in GBM than in healthy controls. Among immune cells, neutrophils showed the greatest changes, resulting in elevated neutrophil-to-lymphocyte ratio (NLR). The neutrophil count inversely correlated with survival time expressed by Spearman's coefficient rs = -0.359 (p = 0.010). The optimal threshold values corresponded to 2.630 × 103/µL for NLR (the area under the ROC curve AUC = 0.831, specificity 90%, sensitivity 76%, the relative risk RR = 7.875, the confidence intervals 95%CI 3.333-20.148). The most considerable changes were recorded in pro-inflammatory cytokines interleukin IL-1β, IL-6, and IL-8, which were approx. 1.5-2-fold higher, whereas tumor necrosis factor α (TNFα) and high mobility group B1 (HMGB1) were lower in GBM than healthy control (p < 0.001). The results of the ROC, AUC, and RR analysis of IL-1β, IL-6, IL-8, and IL-10 indicate their high diagnostics potential for clinical prognosis. The highest average RR was observed for IL-6 (RR = 2.923) and IL-8 (RR = 3.151), which means there is an approx. three-fold higher probability of GBM development after exceeding the cut-off values of 19.83 pg/mL for IL-6 and 10.86 pg/mL for IL-8. The high values of AUC obtained for the models NLR + IL-1β (AUC = 0.907), NLR + IL-6 (AUC = 0.908), NLR + IL-8 (AUC = 0.896), and NLR + IL-10 (AUC = 0.887) prove excellent discrimination of GBM patients from healthy individuals and may represent GBM-specific molecular signatures.

Early growth response 1 promoted the invasion of glioblastoma multiforme by elevating HMGB1

BACKGROUND

Glioblastoma multiforme (GBM) is the most common and deadly glioma subtype. Early growth response 1 (EGR1) participates in the progression of several cancer types, but the expression and function of EGR1 in GBM was rarely investigated.

METHODS

The expressions of EGR1 in GBM were detected with qRT-PCR and immunohistochemistry in 12 pairs of fresh GBM tissues and 116 paraffin-embedded specimens. The patients were divided into high and low EGR1 groups according to the IHC score of EGR1, and the prognostic significances of different groups were evaluated with univariate and multivariate analyses. With in-vitro experiments, we assessed the role of EGR1 in the proliferation and invasion of GBM cells.

RESULTS

In our study, EGR1 was up-regulated in GBM tissues compared with tumor-adjacent normal tissues. High expression of EGR1 or HMGB1 were unfavorable prognostic biomarkers of GBM. Coexpression of EGR1 and HMGB1 could predict the prognosis of GBM more sensitively. EGR1 facilitated the proliferation and invasion of GBM cells. Moreover, EGR1 promoted the invasion, instead of proliferation, of GBM cells by elevating the expression of HMGB1.

CONCLUSIONS

ERG1 was a prognostic biomarker of GBM, and ERG1 and HMGB1 synergistically could predict the GBM prognosis more precisely. ERG1 could promote GBM cell invasion by inducing HMGB1 expression.

S100s and HMGB1 Crosstalk in Pancreatic Cancer Tumors

Pancreatic cancer remains a disease that is very difficult to treat. S100 proteins are small calcium binding proteins with diverse intra- and extracellular functions that modulate different aspects of tumorigenesis, including tumor growth and metastasis. High mobility group box 1 (HMGB1) protein is a multifaceted protein that also actively influences the development and progression of tumors. In this study, we investigate the possible correlations, at the transcript level, between S100s and HMGB1 in pancreatic cancer. For this purpose, we calculated Pearson's correlations between the transcript levels of 13 cancer-related S100 genes and HMGB1 in a cDNA array containing 19 pancreatic cancer tumor samples, and in 8 human pancreatic cancer cell lines. Statistically significant positive correlations were found in 5.5% (5 out of 91) and 37.4% (34 of 91) of the possible S100/S100 or S100/HMGB1 pairs in cells and tumors, respectively. Our data suggest that many S100 proteins crosstalk in pancreatic tumors either with other members of the S100 family, or with HMGB1. These newly observed interdependencies may be used to further the characterization of pancreatic tumors based on S100 and HMGB1 transcription profiles.

Inhibition of DAMP actions in the tumoral microenvironment using lactoferrin-glycyrrhizin conjugate for glioblastoma therapy

BACKGROUND

High-mobility group box-1 (HMGB1) released from the tumor microenvironment plays a pivotal role in the tumor progression. HMGB1 serves as a damaged-associated molecular pattern (DAMP) that induces tumor angiogenesis and its development. Glycyrrhizin (GL) is an effective intracellular antagonist of tumor released HMGB1, but its pharmacokinetics (PK) and delivery to tumor site is deficient. To address this shortcoming, we developed lactoferrin-glycyrrhizin (Lf-GL) conjugate.

METHODS

Biomolecular interaction between Lf-GL and HMGB1 was evaluated by surface plasmon resonance (SPR) binding affinity assay. Inhibition of tumor angiogenesis and development by Lf-GL attenuating HMGB1 action in the tumor microenvironment was comprehensively evaluated through in vitro, ex vivo, and in vivo. Pharmacokinetic study and anti-tumor effects of Lf-GL were investigated in orthotopic glioblastoma mice model.

RESULTS

Lf-GL interacts with lactoferrin receptor (LfR) expressed on BBB and GBM, therefore, efficiently inhibits HMGB1 in both the cytoplasmic and extracellular regions of tumors. Regarding the tumor microenvironment, Lf-GL inhibits angiogenesis and tumor growth by blocking HMGB1 released from necrotic tumors and preventing recruitment of vascular endothelial cells. In addition, Lf-GL improved the PK properties of GL approximately tenfold in the GBM mouse model and reduced tumor growth by 32%. Concurrently, various biomarkers for tumor were radically diminished.

CONCLUSION

Collectively, our study demonstrates a close association between HMGB1 and tumor progression, suggesting Lf-GL as a potential strategy for coping with DAMP-related tumor microenvironment. HMGB1 is a tumor-promoting DAMP in the tumor microenvironment. The high binding capability of Lf-GL to HMGB1 inhibits tumor progression cascade such as tumor angiogenesis, development, and metastasis. Lf-GL targets GBM through interaction with LfR and allows to arrest HMGB1 released from the tumor microenvironment. Therefore, Lf-GL can be a GBM treatment by modulating HMGB1 activity.

Hypoxia-induced HMGB1 promotes glioma stem cells self-renewal and tumorigenicity via RAGE

Glioma stem cells (GSCs) in the hypoxic niches contribute to tumor initiation, progression, and recurrence in glioblastoma (GBM). Hypoxia induces release of high-mobility group box 1 (HMGB1) from tumor cells, promoting the development of tumor. Here, we report that HMGB1 is overexpressed in human GBM specimens. Hypoxia promotes the expression and secretion of HMGB1 in GSCs. Furthermore, silencing HMGB1 results in the loss of stem cell markers and a reduction in self-renewal ability of GSCs. Additionally, HMGB1 knockdown inhibits the activation of RAGE-dependent ERK1/2 signaling pathway and arrests the cell cycle in GSCs. Consistently, FPS-ZM1, an inhibitor of RAGE, downregulates HMGB1 expression and the phosphorylation of ERK1/2, leading to a reduction in the proliferation of GSCs. In xenograft mice of GBM, HMGB1 knockdown inhibits tumor growth and promotes mouse survival. Collectively, these findings uncover a vital function for HMGB1 in regulating GSC self-renewal potential and tumorigenicity.

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Glioma stem cells overexpress HMGB1 in human glioblastoma

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Hypoxia induces the upregulation and release of HMGB1 in glioma stem cells

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HMGB1 promotes the self-renewal of glioma stem cells via RAGE

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Targeting HMGB1 inhibits the tumorigenesis of glioma stem cells

Up-regulation of LINC00665 contributes to the progression of glioma and correlates with its MRI characteristics

BACKGROUND

LncRNA LINC00665 partakes in controlling the malignant phenotype of cancer cells, but its role in glioma and the related regulatory mechanism remain uncertain.

METHODS

RT-PCR was exploited to examine LINC00665 expression. The relationships among the LINC00665 expression, the clinicopathologic values and magnetic resonance imaging (MRI) characteristics of glioma were analyzed. The multiplication, movement, and aggressiveness of glioma cell lines were evaluated by CCK-8, EdU, and Transwell experiments after constructing LINC00665 overexpression and LINC00665 knockdown cell models. A dual-luciferase reporter gene experiment and RIP experiment were executed to validate the interactions between LINC00665 and miR-129-5p, and between miR-129-5p and HMGB1. Western blot and RT-PCR were conducted to find the impact of LINC00665 and miR-129-5p on HMGB1 expression. Nude mouse model was also constructed to examine the impact of LINC00665 on multiplication and aggressiveness of glioma cells in vivo.

RESULTS

LINC00665 expression was markedly increased in glioma. High LINC00665 expression in glioma was closely linked to larger tumor diameter, higher pathologic grade, heterogeneous MRI signal of the tumor, increased peritumoral edema, and stronger MRI enhancement characteristics. LINC00665 overexpression facilitated the malignant behavior of glioma cells, while LINC00665 knockdown played the reverse role. Mechanistically, LINC00665 could decoy miR-129-5p, and indirectly increased HMGB1 expression.

CONCLUSION

LINC00665 functions as an oncogenic lncRNA in glioma, to accelerate glioma progression by modulating miR-129-5p and increasing HMGB1 expression.

Role of Extracellular High-Mobility Group Box-1 as a Therapeutic Target of Gastric Cancer

Background: High-mobility group box-1 (HMGB1) is involved in the tumorigenesis and metastasis of various cancers. The present study investigated the roles of extracellular HMGB1 in the progression of gastric cancer (GC) and the therapeutic effects of recombinant human soluble thrombomodulin (rTM) targeting HMGB1. Methods: The effects of extracellular HMGB1 and rTM on GC cells were assessed using proliferation and Transwell assays. Their effects on local tumor growth and metastasis were evaluated using subcutaneous tumor and liver metastasis mouse models, respectively. Plasma HMGB1 concentrations in GC patients were measured using ELISA. The relationships between plasma HMGB1 concentrations and the prognosis and clinicopathological factors of patients were also investigated. Results: GC proliferation, migration, and invasion abilities were promoted by increases in extracellular HMGB1 concentrations and alleviated by rTM. In the subcutaneous tumor model, local tumor growth was promoted by the addition of rhHMGB1 and alleviated by rTM. Similar changes occurred in the liver metastasis model. Recurrence-free survival (p < 0.01) and overall survival (p = 0.01) were significantly worse in patients with high plasma HMGB1 concentrations. Conclusion: Plasma HMGB1 concentrations are a prognostic marker in GC patients. Extracellular HMGB1 promotes cancer progression and has potential as a novel treatment target in GC cells for rTM.

A novel therapeutic strategy of multimodal nanoconjugates for state-of-the-art brain tumor phototherapy

Background

The outcome of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) for glioblastoma multiforme (GBM), is disappointing due to insufficient photoconversion efficiency and low targeting rate. The development of phototherapeutic agents that target GBM and generate high heat and potent ROS is important to overcome the weak anti-tumor effect.

Results

In this study, nanoconjugates composed of gold nanoparticles (AuNPs) and photosensitizers (PSs) were prepared by disulfide conjugation between Chlorin e6 (Ce6) and glutathione coated-AuNP. The maximum heat dissipation of the nanoconjugate was 64.5 ± 4.5 °C. Moreover, the proximate conjugation of Ce6 on the AuNP surface resulted in plasmonic crossover between Ce6 and AuNP. This improves the intrinsic ROS generating capability of Ce6 by 1.6-fold compared to that of unmodified-Ce6. This process is called generation of metal-enhanced reactive oxygen species (MERos). PEGylated-lactoferrin (Lf-PEG) was incorporated onto the AuNP surface for both oral absorption and GBM targeting of the nanoconjugate (denoted as Ce6-AuNP-Lf). In this study, we explored the mechanism by which Ce6-AuNP-Lf interacts with LfR at the intestinal and blood brain barrier (BBB) and penetrates these barriers with high efficiency. In the orthotopic GBM mice model, the oral bioavailability and GBM targeting amount of Ce6-AuNP-Lf significantly improved to 7.3 ± 1.2% and 11.8 ± 2.1 μg/kg, respectively. The order of laser irradiation, such as applying PDT first and then PTT, was significant for the treatment outcome due to the plasmonic advantages provided by AuNPs to enhance ROS generation capability. As a result, GBM-phototherapy after oral administration of Ce6-AuNP-Lf exhibited an outstanding anti-tumor effect due to GBM targeting and enhanced photoconversion efficiency.

Conclusions

The designed nanoconjugates greatly improved ROS generation by plasmonic crossover between AuNPs and Ce6, enabling sufficient PDT for GBM as well as PTT. In addition, efficient GBM targeting through oral administration was possible by conjugating Lf to the nanoconjugate. These results suggest that Ce6-AuNP-Lf is a potent GBM phototherapeutic nanoconjugate that can be orally administered.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01220-9.

HMGB1 induces radioresistance through PI3K/AKT/ATM pathway in esophageal squamous cell carcinoma

BACKGROUND

To explore the effect of HMGB1 on the radio-sensitivity of esophageal cancer cells through regulating the PI3K/Akt/ATM pathway.

METHODS AND RESULTS

We observed the expression of HMGB1 and p-ATM in biopsies of esophageal cancer patients with immunohistochemical staining. Western blot and RT-qPCR were applied to detect the protein and RNA related to PI3K/Akt/ATM pathway, respectively. In addition, we inhibited the PI3K/Akt pathway with ly294002 and activated it with IGF1, then we explored the invasion, proliferation ability, and apoptosis of esophageal cancer cells in vitro by transwell, CCK8 assay, and flow cytometry respectively. In vivo, xenograft tumor model was established in nude mice to study the effect of HMGB1 on radioresistance via PI3K/AKT/ATM Signaling Pathway. The survival rate in patients with single positive/double negative expression of HMGB1 and p-ATM was significantly higher than in those with both positive expression of HMGB1 and p-ATM, the depletion of HMGB1 combined with ly294002 significantly inhibited cell proliferation and invasion ability, meanwhile, the addition of IGF1 reversed it. Meanwhile, depletion of HMGB1 and ly294002 promoted apoptosis and arrested the cancer cells in G0/G1 cell cycle with the decreased expression of Cyclin D1 and CDK4 and improved P16. We further validated these results in vivo, the application of HMGB1 silencing promoted apoptosis of xenograft tumors after radiation, especially combined with pathway inhibitor ly294002.

CONCLUSIONS

Esophageal cancer patients with high expression of HMGB1 and p-ATM have a poor prognosis after chemo-radiotherapy. Down-regulation of HMGB1 may promote the radio-sensitivity of esophageal cancer cells through regulating PI3K/Akt/ATM pathway.

LGR6 promotes glioblastoma malignancy and chemoresistance by activating the Akt signaling pathway

Chemoresistance is the primary cause of the poor outcome of glioblastoma multiforme (GBM) therapy. Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) is involved in the growth and proliferation of several types of cancer, including gastric cancer and ovarian cancer. Therefore, the aim of the present study was to investigate the role of LGR6 in GBM malignancy and chemoresistance. Cell counting kit-8 and Matrigel®-Transwell assays were conducted to assess GBM cell viability and invasion. The effect of LGR6 on cell cycle progression and activation of Akt signaling was analyzed by performing propidium iodide staining and western blotting, respectively. The results demonstrated that LGR6, a microRNA-1236-3p target candidate, promoted GBM cell viability and invasion, and mediated temozolomide sensitivity in SHG-44 and U251 GBM cells. In addition, LGR6 triggered the activation of the Akt signaling pathway during GBM progression. Collectively, the results of the present study suggested that LGR6 promoted GBM malignancy and chemoresistance, at least in part, by activating the Akt signaling pathway. The results may aid with the identification of a novel therapeutic target and strategy for GBM.

HMGB1 Promotes Resistance to Doxorubicin in Human Hepatocellular Carcinoma Cells by Inducing Autophagy via the AMPK/mTOR Signaling Pathway

Chemoresistance remains as a major hindrance in the treatment of hepatocellular carcinoma (HCC). High mobility group box protein 1 (HMGB1) enhances autophagic flux and protects tumor cells from apoptosis, which results in acquired drug resistance. However, the exact mechanisms underlying HMGB1-modulated autophagy in HCC chemoresistance remain to be defined. In the present study, we found that administration of doxorubicin (DOX) significantly promoted HMGB1 expression and induced HMGB1 cytoplasmic translocation in human HCC cell lines BEL7402 and SMMC7721, which enhanced autophagy that contributes to protecting HCC cells from apoptosis and increasing drug resistance. Moreover, we observed HMGB1 translocation and elevation of autophagy in DOX-resistant BEL7402 and SMMC7721 cells. Additionally, inhibition of HMGB1 and autophagy increased the sensitivities of BEL-7402 and SMMC-7721 cells to DOX and re-sensitized their DOX-resistant cells. Subsequently, we confirmed with HMGB1 regulated autophagy by activating the 5ʹ adenosine monophosphate-activated protein kinase (AMPK)/mTOR pathway. In summary, our results indicate that HMGB1 promotes acquired DOX resistance in DOX-treated BEL7402 and SMMC7721 cells by enhancing autophagy through the AMPK/mTOR signaling pathway. These findings provide the proof-of-concept that HMGB1 inhibitors might be an important targeted treatment strategy for HCC.

Hypoxia and the Receptor for Advanced Glycation End Products (RAGE) Signaling in Cancer

Hypoxia is characterized by an inadequate supply of oxygen to tissues, and hypoxic regions are commonly found in solid tumors. The cellular response to hypoxic conditions is mediated through the activation of hypoxia-inducible factors (HIFs) that control the expression of a large number of target genes. Recent studies have shown that the receptor for advanced glycation end products (RAGE) participates in hypoxia-dependent cellular adaptation. We review recent evidence on the role of RAGE signaling in tumor biology under hypoxic conditions.

Downregulation of high mobility group box 1 enhances the radiosensitivity of non-small cell lung cancer by acting as a crucial target of microRNA-107

High mobility group box 1 (HMGB1) has been reported to regulate the sensitivity of several types of cancer cell to chemoradiotherapy. The present study aimed to investigate the changes in HMGB1 expression after radiotherapy, as well as its regulatory role in the radiosensitivity of non-small cell lung cancer (NSCLC) cells. The expression levels of HMGB1 in the serum of 73 patients with NSCLC were analyzed by ELISA. HMGB1 mRNA and microRNA (miR)-107 expression in NSCLC cells were assessed using reverse transcription-quantitative PCR. Receiver operating characteristic analysis was used to evaluate the diagnostic value of HMGB1. Cell counting kit-8, Transwell invasion and clonogenic assays were used to determine cellular viability, invasiveness and colony formation ability, respectively. Following radiotherapy, the levels of HMGB1 were significantly decreased in the serum of patients with NSCLC, and lower serum levels had relatively high diagnostic accuracy in radiosensitive patients. Furthermore, HMGB1-knockdown retarded cellular proliferation and invasion with or without irradiation, and enhanced NSCLC cell radiosensitivity. Furthermore, knocking down miR-107 reversed the decreases in cellular proliferation and invasiveness both with and without irradiation, and reduced the survival fractions induced by sh-HMGB1. HMGB1-knockdown leads to radiosensitivity that may result from suppression of the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Collectively, decreased expression of HMGB1 was found to be a putative diagnostic predictor of radiosensitivity in patients with NSCLC. HMGB1-knockdown inhibited the proliferation and enhanced the radiosensitivity of NSCLC cells, which may be regulated via miR-107 by mediating the TLR4/NF-κB signaling pathway. Thus, HMGB1 may be a potential regulator of radioresistance in NSCLC, and the HMGB1/miR-107 axis may represent a promising therapeutic target.

Temozolomide Treatment Induces HMGB1 to Promote the Formation of Glioma Stem Cells via the TLR2/NEAT1/Wnt Pathway in Glioblastoma

Formation of glioma stem cells (GSCs) is considered as one of the main reasons of temozolomide (TMZ) resistance in glioma patients. Recent studies have shown that tumor microenvironment-derived signals could promote GSCs formation. But the critical molecule and underlying mechanism for GSCs formation after TMZ treatment is not entirely identified. Our study showed that TMZ treatment promoted GSCs formation by glioma cells; TMZ treatment of biopsy-derived glioblastoma multiforme cells upregulated HMGB1; HMGB1 altered gene expression profile of glioma cells with respect to mRNA, lncRNA and miRNA. Furthermore, our results showed that TMZ-induced HMGB1 increased the formation of GSCs and when HMGB1 was downregulated, TMZ-mediated GSCs formation was attenuated. Finally, we showed that the effect of HMGB1 on glioma cells was mediated by TLR2, which activated Wnt/β-catenin signaling to promote GSCs. Mechanistically, we found that HMGB1 upregulated NEAT1, which was responsible for Wnt/β-catenin activation. In conclusion, TMZ treatment upregulates HMGB1, which promotes the formation of GSCs via the TLR2/NEAT1/Wnt pathway. Blocking HMGB1-mediated GSCs formation could serve as a potential therapeutic target for preventing TMZ resistance in GBM patients.

Exosomes from 3D culture of marrow stem cells enhances endothelial cell proliferation, migration, and angiogenesis via activation of the HMGB1/AKT pathway

BACKGROUND

Angiogenesis is an essential step in tissue engineering. MSC exosomes play an important role in angiogenesis. Functional biomolecules in exosomes vested by the culture microenvironment can be transferred to recipient cells and affects their effect. 3D culture can improve the proliferation and activity of MSCs. However, whether exosomes derived from 3D culture of MSCs have an enhanced effect on angiogenesis is unclear.

METHODS

Herein, we compared the bioactivity of exosomes produced by conventional 2D culture (2D-exos) and 3D culture (3D-exos) of bone marrow stem cells (BMSCs) in angiogenesis.

RESULTS

A series of in vitro and in vivo experiments indicated that 3D-exos exhibited stronger effects on HUVEC cell proliferation, migration, tube formation, and in vivo angiogenesis compared with 2D-exos. Moreover, the superiority of 3D-exos might be attributed to the activation of HMGB1/AKT signaling.

CONCLUSIONS

These results indicate that exosomes from 3D culture of MSCs may serve as a potential therapeutic approach for pro-angiogenesis.

TREM-1 and TREM-2 Expression on Blood Monocytes Could Help Predict Survival in High-Grade Glioma Patients

Objective

In recent years, the role of the modern inflammatory markers TREM-1 (triggering receptors expressed on myeloid cells) and HMGB1 (high mobility group box 1 protein) in tumorigenesis has begun to be studied. Their role in gliomas is not clear. The aim of our study was to find the role of inflammation in gliomas. Patients and Methods. In 63 adult patients with gliomas and 31 healthy controls, the expressions of TREM-1 and TREM-2 on CD14⁺ blood cells (method: flow cytometry) and the levels of soluble sTREM-1, HMGB1, IL-6, and IL-10 (Elisa tests) were analyzed.

Results

Cox proportional hazard analysis showed that a TREM-1/TREM-2 ratio was associated with reduced overall survival (HR = 1.001, P = 0.023). Patients with a TREM-1/TREM-2 ratio above 125 survived significantly shorter than patients with a TREM-1/TREM-2 ratio below 125. The percentage of CD14⁺ TREM-1⁺ cells was strongly associated with a plasma IL-6/IL-10 ratio (positively) and with IL-10 (negatively). Conversely, we found a higher percentage of CD14⁺ TREM-2⁺ monocytes in better surviving patients; these cells could downregulate the exaggerated inflammation and potentiate the phagocytosis in the tumor. The serum levels of HMGB1 negatively correlated with the percentage of CD14⁺ TREM-1⁺ cells and with the TREM-1/TREM-2 ratio. The positive correlation between the serum levels of a late proinflammatory cytokine HMGB1 with the percentage of TREM2⁺ CD14⁺ monocytes can be explained as an effort for suppression of systemic inflammation by anti-inflammatory acting CD14⁺ TREM-2⁺ cells.

Conclusion

We showed that the TREM-1/TREM-2 ratio (expression on the surface of blood monocytes) could help predict prognosis in patients with gliomas, especially in high-grade gliomas, and that systemic inflammation has an impact on the patient's overall survival. This is the first study that showed that TREM expression on monocytes in peripheral blood could help predict prognosis in patients with gliomas.

Bioinformatics Analysis of the Expression of ATP Binding Cassette Subfamily C Member 3 (ABCC3) in Human Glioma

Objective

To investigate the expression of the ABCC3 gene in human glioma and its correlation with the patient’s prognosis.

Methods

The cancer genome atlas (TCGA) database was used to analyze the differential expression of the ABCC3 gene in human glioma. The STRING database was used to construct the protein-protein interaction (PPI) network of the ABCC3 gene coding protein. The co-expression genes relevant to the ABCC3 gene were analyzed by the Pearson correlation test. A log-rank test was used to analyze the difference of overall survival (OS) and disease-free survival (DFS) between the high and low ABCC3 gene expression groups.

Results

The expression level of the ABCC3 gene in glioma tissues was lower than that of corresponding normal brain tissues. The PPI network contains 51 nodes with the average node degree of 13.3 and the local clustering coefficient of 0.72 which indicated that the PPI enrichment was significant (p<0.001). Ten hub genes (ABCC3,NR1I2,NR1H4,-CYP7A1,SLC10A1,CYP3A4,UGT1A1,UGT1A8,UGT1A6 and ALB) were identified by the cytoscape software. The KEGG analysis was enriched in drug metabolism - cytochrome P450 and PPAR signaling pathway. CFI gene expression level was positive correlated with the ABCC3 expression level (r=0.71, p<0.05). And the CNRIP1 gene expressed was negative correlated with ABCC3 expression (r=-0.43, p<0.05). The overall survival (HR=2.8, P<0.05) and disease-free survival rates (HR=2.0, P<0.05) of patients with ABCC3 low expression glioma were significantly higher than those of patients with high expression of ABCC3. Conclusion The expression level of the ABCC3 gene in glioma was decreased compared to normal brain tissue. The overall survival and disease-free survival of in the ABCC3 low-expression group was significant decreased.

The association between high mobility group box 1 chromatin protein and mitotic chromosomes in glioma cells

High mobility group box 1 (HMGB1) is an abundant non-histone nuclear protein that functions as a structural protein of chromatin, regulating genome replication and recombination, mRNA transcription and DNA repair. HMGB1 has been implicated in the tumorigenesis of various cancer types, and the upregulation of HMGB1 has been demonstrated in glioma cells. However, the association between HMGB1 and the mitotic chromosomes in glioma remains uncharacterized. In the present study, the sub-cellular localization of HMGB1 in glioma tissues and cells was investigated. In addition, enhanced green fluorescent protein (EGFP)-tagging of the human HMGB1 protein and chromosome spreading were used to investigate the combination of HMGB1 with mitotic chromosomes. The results of the current study indicated that HMGB1 was localized to the nucleus and the cytoplasm, and it was determined to combine with the condensed chromosomes of proliferating cells in paraformaldehyde (PFA)-fixed glioma tissues. However, HMGB1 was also associated with interphase (but not mitotic chromosomes) when fixed with chilled methanol and 5% (v/v) acetic acid or PFA in vitro. Data from live cell imaging and chromosome spreading indicated the association of HMGB1 with mitotic chromosomes in glioma cells. The present results suggest that HMGB1 combines with mitotic chromosomes in glioma cells, and that the use of fixatives may result in the dissociation of the HMGB1-DNA interaction. Therefore, in live specimens and chromosome spreads, EGFP fusion proteins may represent an accurate indicator for the determination of the correct localization and interaction of HMGB1 in glioma cells.

Tivantinib Hampers the Proliferation of Glioblastoma Cells via PI3K/Akt/Mammalian Target of Rapamycin (mTOR) Signaling

Background

Glioblastoma, the most common and malignant glial tumor, often has poor prognosis. Tivantinib has shown its potential in treating c-Met-high carcinoma. No studies have explored whether tivantinib inhibits the development of glioblastoma.

Material/Methods

The correlation between c-Met expression and clinicopathological characteristics of glioblastoma was investigated. U251 and T98MG glioblastoma cells treated with tivantinib, PI3K inhibitor (LY294002), PI3K activator (740 Y-P), and/or mammalian target of rapamycin (mTOR) inhibitor were subjected to MTT assay or colony formation assay to evaluate cell proliferation. The expression of mTOR signaling and caspase-3 in tivantinib-treated glioblastoma cells was differentially measured by western blotting.

Results

In a group of Chinese patients, expression of c-Met was elevated with the size of glioblastoma, but not with the other clinicopathological characteristics, including gender, age, grade, IDH status, 1p/19q status, and Ki67 status. High dose of tivantinib (1 μmol/L) obviously repressed the proliferation and colony formation of U251 and T98MG glioblastoma cells, but low dose (0.1 μmol/L) of tivantinib failed to retard cell proliferation. Tivantinib blocked PI3K/Akt/mTOR signaling but did not change the expression of cleaved caspase-3. PI3K activator 740 Y-P (20 μmol/L) significantly rescued tivantinib-induced decrease of cell proliferation. Tivantinib (1 μmol/L) in combination with PI3K inhibitor LY294002 (0.5 μmol/L) and mTOR inhibitor rapamycin (0.1 nmol/L) largely inhibited the proliferation of glioblastoma cells.

Conclusions

c-MET inhibitor tivantinib blocks PIKE/Akt/mTOR signaling and hampers the proliferation of glioblastoma cells, which endows the drug a therapeutic effect.

Identification of SEC61G as a Novel Prognostic Marker for Predicting Survival and Response to Therapies in Patients with Glioblastoma

BACKGROUND The survival and therapeutic outcome vary greatly among glioblastoma (GBM) patients. Treatment resistance, including resistance to temozolomide (TMZ) and radiotherapy, is a great obstacle for these therapies. In this study, we aimed to evaluate the predictive value of SEC61G on survival and therapeutic response in GBM patients. MATERIAL AND METHODS Survival analyses were performed to assess the correlation between SEC61G expression and survival of GBM patients from the Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) datasets. Univariate and multivariate Cox proportional hazard regression analysis was introduced to determine prognostic factors with independent impact power. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were conducted to illustrate possible biological functions of SEC61G. RESULTS High expression of SEC61G was significantly correlated with poor prognosis in all GBM patients. High expression of SEC61G was also associated with poor outcome in those who received TMZ treatment or radiotherapy in TCGA GBM cohort. Univariate and multivariate Cox proportional hazards regression demonstrated that SEC61G was an independent prognostic factor affecting the prognosis and therapeutic outcome. The combination of age, SEC61G expression, and MGMT promoter methylation in survival analysis could provide better outcome assessment. Finally, a strong correlation between SEC61G expression and Notch pathway was observed in GSEA and GSVA, which suggested a possible mechanism that SEC61G affected survival and TMZ resistance. CONCLUSIONS SEC61G expression may be a potential prognostic marker of poor survival, and a predictor of poor outcome to TMZ treatment and radiotherapy in GBM patients.