High-Mobility Group Box 1 (HMGB1) Promotes Angiogenesis and Tumor Migration by Regulating Hypoxia-Inducible Factor 1 (HIF-1α) Expression via the Phosphatidylinositol 3-Kinase (PI3K)/AKT Signaling Pathway in Breast Cancer Cells

Multiple functions of HMGB1 in cancer

High mobility group box 1 (HMGB1) is a nuclear DNA-binding protein with a dual role in cancer, acting as an oncogene and a tumor suppressor. This protein regulates nucleosomal structure, DNA damage repair, and genomic stability within the cell, while also playing a role in immune cell functions. This review comprehensively evaluates the biological and clinical significance of HMGB1 in cancer, including its involvement in cell death and survival, its potential as a therapeutic target and cancer biomarker, and as a prosurvival signal for the remaining cells after exposure to cytotoxic anticancer treatments. We highlight the need for a better understanding of the cellular markers and mechanisms involved in the involvement of HMGB1in cancer, and aim to provide a deeper understanding of its role in cancer progression.

USP15 promotes the progression of papillary thyroid cancer by regulating HMGB1 stability through its deubiquitination

Purpose: Papillary thyroid cancer (PTC) stands as one of the most prevalent types of thyroid cancers, characterized by a propensity for in-situ recurrence and distant metastasis. The high mobility group protein (HMGB1), a conserved nuclear protein, plays a pivotal role in carcinogenesis by stimulating tumor cell growth and migration. Nevertheless, the underlying mechanism driving aberrant HMGB1 expression in PTC necessitates further elucidation. Materials and methods: Our study unraveled the impact of low and overexpression of USP15 on the proliferation, invasion, and metastasis of PTC cells. Through a comprehensive array of molecular techniques, we uncovered the intricate relationship between HMGB1 and USP15 in the progression of PTC. Results: In this study, we identified USP15, a deubiquitinase in the ubiquitin-specific proteases family, as a true deubiquitylase of HMGB1 in PTC. USP15 was shown to interact with HMGB1 in a deubiquitination activity-dependent manner, deubiquitinating and stabilizing HMGB1. USP15 depletion significantly decreased PTC cell proliferation, migration, and invasion. In addition, the effects induced by USP15 depletion could be rescued by further HMGB1 overexpression. But when HMGB1 is knocked down, even overexpression of USP15 could not promote the progression of PTC cells. Conclusion: In essence, our discoveries shed light on the previously uncharted catalytic role of USP15 as a deubiquitinating enzyme targeting HMGB1, offering a promising avenue for potential therapeutic interventions in the management of PTC.

HMGB1 enhances the migratory and invasive abilities of A2780/DDP cells by facilitating epithelial to mesenchymal transition via GSK‑3β

The aim of the present study was to investigate the impact and mechanism of high mobility group box 1 (HMGB1) on the regulation of cell migration and invasion in A2780/DDP cisplatin-resistant ovarian cancer cells. After transfecting small interfering (si)RNA-HMGB1 into A2780/DDP cells, Transwell migration and invasion assays were conducted to assess alterations in the cell migratory and invasive abilities. Additionally, western blotting analyses were performed to examine changes in HMGB1, phosphorylated (p)-GSK-3β, GSK-3β, E-cadherin and vimentin expression levels. The results of the present study demonstrated that the migratory and invasive abilities of A2780/DDP cells were significantly higher compared with those of A2780 cells. Additionally, the expression levels of HMGB1, p-GSK-3β and the mesenchymal phenotype marker, vimentin, in A2780/DDP cells were significantly elevated relative to the levels in A2780 cells. Conversely, the expression level of the epithelial phenotype marker, E-cadherin, was markedly decreased compared with that in A2780 cells. Following transfection of A2780/DDP cells with siRNA-HMGB1, there was a significant reduction in the rate of cell migration and invasion. Simultaneously, the expression levels of HMGB1, p-GSK-3β and vimentin were downregulated while the level of E-cadherin was upregulated. It was therefore concluded that the high expression of HMGB1 in A2780/DDP cells enhanced the cell migration and invasion abilities by facilitating epithelial to mesenchymal transition via GSK-3β.

HMGB1: a double-edged sword and therapeutic target in the female reproductive system

HMGB1 that belongs to the High Mobility Group-box superfamily, is a nonhistone chromatin associated transcription factor. It is present in the nucleus of eukaryotes and can be actively secreted or passively released by kinds of cells. HMGB1 is important for maintaining DNA structure by binding to DNA and histones, protecting it from damage. It also regulates the interaction between histones and DNA, affecting chromatin packaging, and can influence gene expression by promoting nucleosome sliding. And as a DAMP, HMGB1 binding to RAGE and TLRs activates NF-κB, which triggers the expression of downstream genes like IL-18, IL-1β, and TNF-α. HMGB1 is known to be involved in numerous physiological and pathological processes. Recent studies have demonstrated the significance of HMGB1 as DAMPs in the female reproductive system. These findings have shed light on the potential role of HMGB1 in the pathogenesis of diseases in female reproductive system and the possibilities of HMGB1-targeted therapies for treating them. Such therapies can help reduce inflammation and metabolic dysfunction and alleviate the symptoms of reproductive system diseases. Overall, the identification of HMGB1 as a key player in disease of the female reproductive system represents a significant breakthrough in our understanding of these conditions and presents exciting opportunities for the development of novel therapies.

Implications of receptor for advanced glycation end products for progression from obesity to diabetes and from diabetes to cancer

Obesity and type 2 diabetes mellitus (T2DM) are chronic pathologies with a high incidence worldwide. They share some pathological mechanisms, including hyperinsulinemia, the production and release of hormones, and hyperglycemia. The above, over time, affects other systems of the human body by causing tissue hypoxia, low-grade inflammation, and oxidative stress, which lay the pathophysiological groundwork for cancer. The leading causes of death globally are T2DM and cancer. Other main alterations of this pathological triad include the accumulation of advanced glycation end products and the release of endogenous alarmins due to cell death (i.e., damage-associated molecular patterns) such as the intracellular proteins high-mobility group box protein 1 and protein S100 that bind to the receptor for advanced glycation products (RAGE) - a multiligand receptor involved in inflammatory and metabolic and neoplastic processes. This review analyzes the latest advanced reports on the role of RAGE in the development of obesity, T2DM, and cancer, with an aim to understand the intracellular signaling mechanisms linked with cancer initiation. This review also explores inflammation, oxidative stress, hypoxia, cellular senescence, RAGE ligands, tumor microenvironment changes, and the “cancer hallmarks” of the leading tumors associated with T2DM. The assimilation of this information could aid in the development of diagnostic and therapeutic approaches to lower the morbidity and mortality associated with these diseases.

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.

Interactions between non-coding RNAs and HIF-1α in the context of cancer

Hypoxia-inducible factor 1α (HIF-1α) is a subunit of the HIF-1 transcription factor which is encoded by the HIF1A gene. This transcription factor is the main modulator of the cell response to hypoxia. Hypoxia-induced up-regulation of HIF-1α is involved in the pathogenesis of cancer. Recently, the interactions of several long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) with HIF-1α have been reported. These ncRNAs regulate the expression of HIF-1α through different mechanisms. The regulatory roles of ncRNAs on HIF-1α are involved in the response of cancer cells to a wide range of anticancer drugs such as sorafenib, cisplatin, propofol, doxorubicin, and paclitaxel. Therefore, identification of the complex network between ncRNAs and HIF-1α not only facilitates the design of novel therapies but also promotes the efficacy of conventional anticancer treatments. This review aims to explain the interactions between these classes of ncRNAs and HIF-1α in the context of cancer.

Extra-Cellular Vesicles Derived from Thyroid Cancer Cells Promote the Epithelial to Mesenchymal Transition (EMT) and the Transfer of Malignant Phenotypes through Immune Mediated Mechanisms

Thyroid cancer is the most common endocrine cancer, and its incidence is increasing in many countries around the world. Among thyroid cancers, the papillary thyroid cancer (PTC) histotype is particularly prevalent. A small percentage of papillary tumors is associated with metastases and aggressive behavior due to de-differentiation obtained through the epithelial-mesenchymal transition (EMT) by which epithelial thyroid cells acquire a fibroblast-like morphology, reduce cellular adhesion, increase motility and expression of mesenchymal proteins. The tumor microenvironment plays an important role in promoting an aggressive phenotype through hypoxia and the secretion of HMGB1 and other factors. Hypoxia has been shown to drastically change the tumor cell phenotype and has been associated with increasing metastatic and migratory behavior. Cells transfer information to neighboring cells or distant locations by releasing extracellular membrane vesicles (EVs) that contain key molecules, such as mRNAs, microRNAs (miRNAs), and proteins, that are able to modify protein expression in recipient cells. In this study, we investigated the potential role of EVs released by the anaplastic cancer cell line CAL-62 in inducing a malignant phenotype in a papillary cancer cell line (BCPAP).

Conducive target range of breast cancer: Hypoxic tumor microenvironment

Breast cancer is a kind of malignant tumor disease that poses a serious threat to human health. Its biological characteristics of rapid proliferation and delayed angiogenesis, lead to intratumoral hypoxia as a common finding in breast cancer. HIF as a transcription factor, mediate a series of reactions in the hypoxic microenvironment, including metabolic reprogramming, tumor angiogenesis, tumor cell proliferation and metastasis and other important physiological and pathological processes, as well as gene instability under hypoxia. In addition, in the immune microenvironment of hypoxia, both innate and acquired immunity of tumor cells undergo subtle changes to support tumor and inhibit immune activity. Thus, the elucidation of tumor microenvironment hypoxia provides a promising target for the resistance and limited efficacy of current breast cancer therapies. We also summarize the hypoxic mechanisms of breast cancer treatment related drug resistance, as well as the current status and prospects of latest related drugs targeted HIF inhibitors.

HMGB1 mediates invasion and PD-L1 expression through RAGE-PI3K/AKT signaling pathway in MDA-MB-231 breast cancer cells

BACKGROUND

High-mobility group box 1 (HMGB1) is increased in breast cancer cells as the result of exposure to the secreted substances from cancer-associated fibroblasts and plays a crucial role in cancer progression and drug resistance. Its effect, however, on the expression of programmed death ligand 1 (PD-L1) in breast cancer cells has not been investigated. This study aimed to investigate the mechanism of HMGB1 through receptors for advanced glycation end products (RAGE) on cell migration/invasion and PD-L1 expression in breast cancer cells.

METHODS

A 3-dimensional (3-D) migration and invasion assay and Western blotting analysis to evaluate the function and the mechanism under recombinant HMGB1 (rHMGB1) treatment with knockdown of RAGE using shRAGE and PI3K/AKT inhibitors was performed.

RESULTS

The results revealed that rHMGB1 induced MDA-MB-231 cell migration and invasion. The knockdown of RAGE using shRAGE and PI3K/AKT inhibitors attenuated 3-D migration and invasion in response to rHMGB1 compared to mock cells. PD-L1 up-regulation was observed in both parental MDA-MB-231 (P) and MDA-MB-231 metastasis to bone marrow (BM) cells treated with rHMGB1, and these effects were alleviated in RAGE-knock down (KD) breast cancer cells as well as in PI3K/AKT inhibitor-treated cells.

CONCLUSIONS

Collectively, these findings indicate that HMGB1-RAGE through PI3K/AKT signaling promotes not only breast cancer cell invasion but also PD-L1 expression which leads to the destruction of the effector T cells. The attenuating HMGB1-RAGE-PI3K/AKT pathway may help to attenuate breast cancer cell aggressive phenotypes.

A PDE Model of Breast Tumor Progression in MMTV-PyMT Mice

The evolution of breast tumors greatly depends on the interaction network among different cell types, including immune cells and cancer cells in the tumor. This study takes advantage of newly collected rich spatio-temporal mouse data to develop a data-driven mathematical model of breast tumors that considers cells' location and key interactions in the tumor. The results show that cancer cells have a minor presence in the area with the most overall immune cells, and the number of activated immune cells in the tumor is depleted over time when there is no influx of immune cells. Interestingly, in the case of the influx of immune cells, the highest concentrations of both T cells and cancer cells are in the boundary of the tumor, as we use the Robin boundary condition to model the influx of immune cells. In other words, the influx of immune cells causes a dominant outward advection for cancer cells. We also investigate the effect of cells' diffusion and immune cells' influx rates in the dynamics of cells in the tumor micro-environment. Sensitivity analyses indicate that cancer cells and adipocytes' diffusion rates are the most sensitive parameters, followed by influx and diffusion rates of cytotoxic T cells, implying that targeting them is a possible treatment strategy for breast cancer.

Role of high-mobility group box 1 in cancer

High-mobility group box 1 (HMGB1) is a non-histone nuclear protein in most eukaryocytes. Inside the nucleus, HMGB1 plays an important role in several DNA events such as DNA repair, transcription, telomere maintenance, and genome stability. While outside the nucleus, it fulfils more complicated functions, including promoting cell proliferation, inflammation, angiogenesis, immune tolerance and immune escape, which may play a pro-tumoral role.Meanwhile, HMGB1 acts as an anti-tumoral protein by regulating immune cell recruitment and inducing immunogenic cell death (ICD) during the carcinogenesis process. Therefore, abnormal expression of HMGB1 is associated with oncogenesis, development, and metastasis of cancer, which may play a dual role of pro-tumor and anti-tumor.

High Mobility Group Box 1: Biological Functions and Relevance in Oxidative Stress Related Chronic Diseases

In the early 1970s, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and named high-mobility group (HMG) proteins. High-mobility group box 1 (HMGB1) is the most studied HMG protein that detects and coordinates cellular stress response. The biological function of HMGB1 depends on its subcellular localization and expression. It plays a critical role in the nucleus and cytoplasm as DNA chaperone, chromosome gatekeeper, autophagy maintainer, and protector from apoptotic cell death. HMGB1 also functions as an extracellular alarmin acting as a damage-associated molecular pattern molecule (DAMP). Recent findings describe HMGB1 as a sophisticated signal of danger, with a pleiotropic function, which is useful as a clinical biomarker for several disorders. HMGB1 has emerged as a mediator in acute and chronic inflammation. Furthermore, HMGB1 targeting can induce beneficial effects on oxidative stress related diseases. This review focus on HMGB1 redox status, localization, mechanisms of release, binding with receptors, and its activities in different oxidative stress-related chronic diseases. Since a growing number of reports show the key role of HMGB1 in socially relevant pathological conditions, to our knowledge, for the first time, here we analyze the scientific literature, evaluating the number of publications focusing on HMGB1 in humans and animal models, per year, from 2006 to 2021 and the number of records published, yearly, per disease and category (studies on humans and animal models).

miR-142-3p simultaneously targets HMGA1, HMGA2, HMGB1, and HMGB3 and inhibits tumorigenic properties and in-vivo metastatic potential of human cervical cancer cells

AIMS

High-mobility group (HMG) proteins are oncogenic in different cancers, including cervical cancer; silencing their individual expression using sh-RNAs, siRNAs, and miRNAs has had anti-tumorigenic effects, but the consequences of their collective downregulation are not known. Since multiple gene targeting is generally very effective in cancer therapy, the present study highlighted the consequences of silencing the expression of HMGA1, A2, B1, and B3 using sh-RNAs or miR-142-3p (that can potentially target HMGA1, A2, B1, and B3) in cervical cancer cell lines.

MAIN METHODS

3' UTR luciferase reporter assays were performed to validate HMGA1, A2, B1, and B3 as targets of miR-142-3p in human cervical cancer cells. Annexin V/PI dual staining and flow cytometry analyses were used to detect apoptotic cells. miR-142-3p-mediated regulation of cell death, colony formation, migration, and invasion was investigated in human cervical cancer cells together with in vivo metastasis in zebrafish.

KEY FINDINGS

Concurrent knockdown of HMGA1, A2, B1, and B3 through their corresponding sh-RNAs inhibited cell viability and colony formation but induced apoptosis, and these effects were relatively reduced upon their individual knockdown. miR-142-3p targeted HMGA1, A2, B1, and B3 by binding to their 3'UTRs and induced apoptosis but inhibited proliferation, migration, and invasion of human cervical cancer cells. In addition, miR-142-3p expression decreased phospho-p65 and EMT-related proteins in cervical cancer cells and their in vivo metastatic potential upon implantation in zebrafish.

SIGNIFICANCE

These findings suggest that miR-142-3p acts as a tumor-suppressive miRNA by targeting HMGA1, A2, B1, and B3 and may serve as a potential therapeutic agent in human cervical cancer.

Current and Future Therapies for Immunogenic Cell Death and Related Molecules to Potentially Cure Primary Breast Cancer

Simple Summary

How a cure for primary breast cancer after (neo)adjuvant therapy can be achieved at the molecular level remains unclear. Immune activation by anticancer drugs may contribute to the eradication of residual tumor cells by postoperative (neo)adjuvant chemotherapy. In addition, chemotherapy-induced immunogenic cell death (ICD) may result in long-term immune activation by memory effector T cells, leading to the curing of primary breast cancer. In this review, we discuss the molecular mechanisms by which anticancer drugs induce ICD and immunogenic modifications for antitumor immunity and targeted therapy against damage-associated molecular patterns. Our aim was to gain a better understanding of how to eradicate residual tumor cells treated with anticancer drugs and cure primary breast cancer by enhancing antitumor immunity with immune checkpoint inhibitors and vaccines.

Abstract

How primary breast cancer can be cured after (neo)adjuvant therapy remains unclear at the molecular level. Immune activation by anticancer agents may contribute to residual tumor cell eradication with postsurgical (neo)adjuvant chemotherapy. Chemotherapy-induced immunogenic cell death (ICD) may result in long-term immune activation with memory effector T cells, leading to a primary breast cancer cure. Anthracycline and taxane treatments cause ICD and immunogenic modulations, resulting in the activation of antitumor immunity through damage-associated molecular patterns (DAMPs), such as adenosine triphosphate, calreticulin, high mobility group box 1, heat shock proteins 70/90, and annexin A1. This response may eradicate residual tumor cells after surgical treatment. Although DAMP release is also implicated in tumor progression, metastasis, and drug resistance, thereby representing a double-edged sword, robust immune activation by anticancer agents and the subsequent acquisition of long-term antitumor immune memory can be essential components of the primary breast cancer cure. This review discusses the molecular mechanisms by which anticancer drugs induce ICD and immunogenic modifications for antitumor immunity and targeted anti-DAMP therapy. Our aim was to improve the understanding of how to eradicate residual tumor cells treated with anticancer drugs and cure primary breast cancer by enhancing antitumor immunity with immune checkpoint inhibitors and vaccines.

Exosomal HMGB1 derived from hypoxia-conditioned bone marrow mesenchymal stem cells increases angiogenesis via the JNK/HIF-1α pathway

Mesenchymal stem cells (MSCs) have been described to induce angiogenesis in various tissues and have been used for the development of novel cell‐based therapies. Increasing evidence suggests that MSCs execute their paracrine function via the secretion of exosomes, especially under hypoxic conditions. However, the mechanisms by which MSC‐derived exosomes secreted under hypoxia enhance angiogenesis still remain unclear. To study exosome physiology under hypoxic or normoxic conditions, we isolated exosomes from bone marrow mesenchymal stem cells (BMSCs). Furthermore, we detected the uptake of exosomes by human umbilical vein endothelial cells (HUVECs) by immunofluorescence staining. In addition, we determined the effects of exosomes on cell viability, migration and tube formation in HUVECs by Cell Counting Kit‐8, migration and tube formation assays, respectively. We examined the expression of key proteins related to exosome‐induced angiogenesis by BMSCs cultured under hypoxic conditions by western blot. Exosomes released by BMSCs cultured under hypoxic conditions enhanced cell proliferation, migration and angiogenesis of HUVECs. Hypoxia induced the expression of high mobility group box 1 protein (HMGB1) in BMSC‐derived exosomes, and silencing of HMGB1 abolished the angiogenic effect in HUVECs. Furthermore, exosomal HMGB1 activated the JNK signaling pathway and induced hypoxia‐inducible factor‐1α/vascular endothelial growth factor expression, consequently enhancing angiogenesis in HUVECs. Our data reveal that exosomal HMGB1 promotes angiogenesis via JNK/hypoxia‐inducible factor‐1α signaling. Therefore, BMSC exosomes derived under hypoxia may have potential for development of novel treatment strategies for angiogenesis‐related diseases.

[Dihydromyricetin inhibits proliferation and migration of gastric cancer cells through regulating Akt/STAT3 signaling pathways and HMGB1 expression]

OBJECTIVE

To investigate the inhibitory effects of dihydromyricetin on the proliferation and migration of gastric cancer BGC-823 cells and explore the molecular mechanisms.

METHODS

BGC-823 cells in routine culture were treated with different concentrations of dihydromyricetin (0, 40, 60, 80, 100, and 120 μg/mL) for 24 h, and the changes in cell viability were detected using CCK-8 assay; colony forming assay and Transwell assay were performed to assess the changes in colonyforming and migration abilities of the cells, respectively. The levels of MMP-2 and MMP-9 in the treated cells were determined using ELISA, and Western blotting was used to detect the expressions of E-cadherin, N-cadherin, cyclin D1, cyclin E1, HSP70 and HMGB1 and the phosphorylation levels of Akt and Stat3.

RESULTS

CCK-8 assay showed that dihydromyricetin treatment dose-dependently inhibited the viability of BGC-823 cells (P < 0.05). Treatment with dihydromyricetin obviously suppressed the proliferation and migration of BGC-823 cells, significantly reduced the expression levels of cyclin D1, cyclin E1 and Ncadherin, enhanced E-cadherin expression, inhibited the phosphorylation of Akt and stat3, and downregulated HMGB1 expression in the cells. The results of ELISA demonstrated significantly lowered levels of MMP-2 and MMP-9 in dihydromyricetin-treated cells.

CONCLUSIONS

Dihydromyricetin inhibits the proliferation and migration of BGC-823 cells through suppressing the activation of Akt/stat3 signaling pathways and HMGB1 expression.

Circular RNA 0081146 facilitates the progression of gastric cancer by sponging miR-144 and up-regulating HMGB1

OBJECTIVES

Recent studies have revealed that circular RNA (circRNA) plays a pivotal role in cancer development. The study aimed to investigate the role of circ_0081146 in gastric cancer (GC).

RESULTS

Circ_0081146 was upregulated in GC tissues and cells. Patients with high expression of circ_0081146 had a significantly reduced 5-year overall survival rate. Circ_0081146 knockdown restrained the growth, migration and invasion of GC cells in vitro as well as tumorigenesis in vivo. Circ_0081146 targeted miR-144 and HMGB1 was targeted by miR-144. Circ_0081146 was negatively correlated with miR-144 expression, while positively correlated with HMGB1 expression in GC tissues. Moreover, the inhibitory effect of circ_0081146 knockdown on the progression of GC cells were reversed by silencing miR-144 or HMGB1 overexpression. Mechanically, circ_0081146 increased HMGB1 expression by targeting miR-144.

CONCLUSION

Circ_0081146 functions as an oncogene in GC to promote cell growth, migration and invasion via modulating the miR-144/HMGB1 axis.

High mobility group box 1 regulates gastric cancer cell proliferation and migration via RAGE-mTOR/ERK feedback loop

Gastric cancer (GC) is a common malignancy tumour in China. Despite various therapeutic approaches to improve the survival rate of GC patients, the effectiveness of currently available treatments remains unsatisfactory. High mobility group box 1 (HMGB1) is reported to play a role in tumour development. However, the molecular mechanisms involved in HMGB1-mediated regulation of proliferation and migration of GC cells remain unclear. In the present study, we demonstrated that HMGB1 is highly expressed in GC cells and tissue. In HGC-27 GC cells, HMGB1 overexpression or HMGB1 RNA interference both demonstrated that HMGB1 could promote GC cell proliferation and migration. Investigation of the underlying molecular mechanisms revealed that HMGB1 enhanced cyclins expression, induced epithelial-to-mesenchymal transition and matrix metalloproteinase (MMPs) expression and promoted RAGE expression as well as RAGE-mediated activation of Akt/mTOR/P70S6K and ERK/P90RSK/CREB signalling pathways. We also found that inhibition of ERK and mTOR using specific inhibitors reduced recombinant human HMGB1-induced RAGE expression, suggesting that the RAGE-mTOR/ERK positive feedback loop is involved in HMGB1-induced GC cell proliferation and migration. Our study highlights a novel mechanism by which HMGB1 promotes GC cell proliferation and migration via RAGE-mediated Akt-mTOR and ERK-CREB signalling pathways which also involves the RAGE-mTOR/ERK feedback loop. These findings indicate that HMGB1 is a potential therapeutic target for GC.

MiR-126-HMGB1-HIF-1 Axis Regulates Endothelial Cell Inflammation during Exposure to Hypoxia-Acidosis

Crosstalk between molecular regulators miR-126, hypoxia-inducible factor 1-alpha (HIF-1-α), and high-mobility group box-1 (HMGB1) contributes to the regulation of inflammation and angiogenesis in multiple physiological and pathophysiological settings. Here, we present evidence of an overriding role for miR-126 in the regulation of HMGB1 and its downstream proinflammatory effectors in endothelial cells subjected to hypoxia with concurrent acidosis (H/A). Methods. Primary mouse endothelial cells (PMEC) were exposed to hypoxia or H/A to simulate short or chronic low-flow ischemia, respectively. RT-qPCR quantified mRNA transcripts, and proteins were measured by western blot. ROS were quantified by fluorogenic ELISA and luciferase reporter assays employed to confirm an active miR-126 target in the HMGB1 3'UTR. Results. Enhanced expression of miR-126 in PMECs cultured under neutral hypoxia was suppressed under H/A, whereas the HMGB1 expression increased sequentially under both conditions. Enhanced expression of HMGB1 and downstream inflammation markers was blocked by the premiR-126 overexpression and optimized by antagomiR. Compared with neutral hypoxia, H/A suppressed the HIF-1α expression independently of miR-126. The results show that HMGB1 and downstream effectors are optimally induced by H/A relative to neutral hypoxia via crosstalk between hypoxia signaling, miR-126, and HIF-1α, whereas B-cell lymphoma 2(Bcl2), a HIF-1α, and miR-126 regulated gene expressed optimally under neutral hypoxia. Conclusion. Inflammatory responses of ECs to H/A are dynamically regulated by the combined actions of hypoxia, miR-126, and HIF-1α on the master regulator HMGB1. The findings may be relevant to vascular diseases including atherosclerotic occlusion and interiors of plaque where coexisting hypoxia and acidosis promote inflammation as a defining etiology.

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.

DARS-AS1 Knockdown Inhibits the Growth of Cervical Cancer Cells via Downregulating HMGB1 via Sponging miR-188-5p

Background:

Evidence has been shown that long noncoding RNAs (lncRNAs) play an important role in the development of cervical cancer. Recently, lncRNA DARS-AS1 was shown to be dysregulated in several cancer types, but the role of DARS-AS1 in cervical cancer remains unclear.

Methods:

Immunofluorescence staining, flow cytometry and transwell invasion assays were used to determine proliferation, apoptosis and invasion in cervical cancer cells, respectively. The dual luciferase reporter system assay was performed to assess the interaction between DARS-AS1, miR-188-5p, and high mobility group box 1 (HMGB1) in cervical cancer cells.

Results:

Downregulation of DARS-AS1 markedly inhibited the proliferation and invasion of cervical cancer cells. Moreover, DARS-AS1 knockdown obviously induced the apoptosis of SiHa and HeLa cells. Meanwhile, luciferase reporter assay identified that miR-188-5p was the potential miRNA binding of DARS-AS1, and HMGB1 was the potential binding target of miR-188-5p. Mechanistic analysis indicated that downregulation of DARS-AS1 decreased the expression of HMGB1 by acting as a competitive “sponge” of miR-188-5p.

Conclusion:

In this study, we found that DARS-AS1 knockdown suppressed the growth of cervical cancer cells via downregulating HMGB1 via sponging miR-188-5p. Therefore, DARS-AS1 might serve as a potential target for the treatment of cervical cancer.

Three dimensional engineered models to study hypoxia biology in breast cancer

Breast cancer is the second leading cause of mortality among women worldwide. Despite the available therapeutic regimes, variable treatment response is reported among different breast cancer subtypes. Recently, the effects of the tumor microenvironment on tumor progression as well as treatment responses have been widely recognized. Hypoxia and hypoxia inducible factors in the tumor microenvironment have long been known as major players in tumor progression and survival. However, the majority of our understanding of hypoxia biology has been derived from two dimensional (2D) models. Although many hypoxia-targeted therapies have elicited promising results in vitro and in vivo, these results have not been successfully translated into clinical trials. These limitations of 2D models underscore the need to develop and integrate three dimensional (3D) models that recapitulate the complex tumor-stroma interactions in vivo. This review summarizes role of hypoxia in various hallmarks of cancer progression. We then compare traditional 2D experimental systems with novel 3D tissue-engineered models giving accounts of different bioengineering platforms available to develop 3D models and how these 3D models are being exploited to understand the role of hypoxia in breast cancer progression.

A Novel CircRNA Circ_0095424 Regulates Proliferation, Metastasis, and Apoptosis of Osteosarcoma Cells Via the PI3K/AKT Signaling Pathway Through Targeting the miR-1238/HMGB1 Axis

Cancer Biotherapy and Radiopharmaceuticals is officially retracting the article entitled, A Novel CircRNA Circ_0095424 Regulates Proliferation, Metastasis, and Apoptosis of Osteosarcoma Cells Via the PI3K/AKT Signaling Pathway Through Targeting the miR-1238/HMGB1 Axis by Zhang et al., (Cancer Biother Radiopharm epub 19 Aug 2020; DOI: 10.1089/cbr.2020.3563), due to manipulated images appearing in the published paper. The Editor of the journal received an email on August 31, 2020 from the corresponding author of the article, Dr. Chuan Qin, indicating that, ''due to our negligence in organizing the pictures, the protein pictures are repeatedly placed in Figure 7G PI3K. For this, we express our sincerest apologies. We need to [issue] an [erratum] on this issue. We have replaced the protein picture of Figure 7G with the correct picture.'' However, one of the attachments submitted with the request appeared to be the original version of Figure 7 from the accepted manuscript. A second attachment appeared to be the data from three replicates to be used (by the journal) to construct a revised version of Figure 7. The Editor, in turn, informed the authors that it was not at the journal's discretion to create a new image for them, and asked the authors to create the revised figure and supply it to the publisher. Below is the response from Dr. Qin, dated September 2, 2020. "In fact, our team's Western blot experiment commissioned a third-party company for testing. At present, some peers have found that the company has forged experimental reports. We believe that the authenticity of the data provided by the company is problematic. After contacting the company, they were unable to provide the original images. In view of the problems in this manuscript, all the authors discussed and agreed to withdraw the manuscript." As the entirety of the situation is unacceptable, the Editor officially retracts the article based on the "forged experimental reports" and the questionable validity of the data provided. The Editor and Publisher of Cancer Biotherapy and Radiopharmaceuticals is dedicated to preserving the integrity of the scientific literature and the community it serves.

Circular RNA CirCHIPK3 promotes cell proliferation and invasion of breast cancer by sponging miR-193a/HMGB1/PI3K/AKT axis

Background

The aim of this study was to explore the potential mechanism of circular RNA (circRNA) CirCHIPK3 on the malignant proliferation and metastasis of breast cancer (BC).

Methods

Human BC samples and their matched normal adjacent tissues were obtained from 50 patients to assess the expression of CirCHIPK3 and its relationship with BC prognosis. A series of in vitro and in vivo functional experiments were carried out to elucidate the role of CirCHIPK3 in BC progression and its underlying molecular mechanisms. Moreover, the interaction of CirCHIPK3, miR‐193a, and HMGB1 was examined using bioinformatics, FISH, RIP, RNA‐pull down and luciferase reporter assays. Western blot analysis was performed to examine the expression of HMGB1, p‐PI3K, total PI3K, p‐AKT, and AKT after si‐CirCHIPK3 transfection.

Results

Upregulation of CirCHIPK3 was identified in BC, which predicted a worse prognosis in BC patients. Furthermore, it was found that CirCHIPK3 facilitated cell proliferation, migration, and invasion in BC by regulating miR‐193a/HMGB1/PI3K/AKT signaling. CirCHIPK3 acted as a sponge for miR‐193a to facilitate HMGB1 expression. si‐CirCHIPK3 also inhibited tumor growth of BC in nude mice. si‐CircCHIPK3 decreased HMGB1/PI3K/AKT signal expression in MDA‐MB‐231 cells, whereas overexpression of CircCHIPK3 enhanced HMGB1/PI3K/AKT signal.

Conclusions

CirCHIPK3 regulated miR‐193a/HMGB1/PI3K/AKT signaling to facilitate BC development and progression, providing a novel therapeutic target for BC.

High Mobility Group Box 1 in Human Cancer

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

Hypoxia-responsive miR-141-3p is involved in the progression of breast cancer via mediating the HMGB1/HIF-1α signaling pathway

Background

Hypoxia‐responsive miRs have been frequently reported in the growth of various malignant tumors. The present study aimed to investigate whether hypoxia‐responsive miR‐141–3p was implicated in the pathogenesis of breast cancer via mediating the high‐mobility group box protein 1 (HMGB1)/hypoxia‐inducible factor (HIF)‐1α signaling pathway.

Materials and methods

miRs expression profiling was filtrated by miR microarray assays. Gene and protein expression levels, respectively, were examined by a quantitative reverse transcriptase‐polymerase chaion reaction and western blotting. Cell migration and invasion were analyzed using a transwell assay. Cell growth was determined using nude‐mouse transplanted tumor experiments.

Results

miR‐141–3p was observed as a hypoxia‐responsive miR in breast cancer. miR‐141–3p was down‐regulated in breast cancer specimens and could serve as an independent prognostic factor for predicting overall survival in breast cancer patients. In addition, the overexpression of miR‐141–3p could inhibit hypoxia‐induced cell migration and impede human breast cancer MDA‐MB‐231 cell growth in vivo. Mechanistically, the hypoxia‐related HMGB1/HIF‐1α signaling pathway might be a possible target of miR‐141–3p with respect to preventing the development of breast cancer.

Conclusions

Our finding provides a new mechanism by which miR‐141–3p could prevent hypoxia‐induced breast tumorigenesis via post‐transcriptional repression of the HMGB1/HIF‐1α signaling pathway.

Identification of hub genes in papillary thyroid carcinoma: robust rank aggregation and weighted gene co-expression network analysis

BACKGROUND

Papillary thyroid carcinoma (PTC), which is the most common endocrine malignancy, has been steadily increasing worldwide in incidence over the years, while mechanisms underlying the pathogenesis and diagnostic for PTC are incomplete. The purpose of this study is to identify potential biomarkers for diagnosis of PTC, and provide new insights into pathogenesis of PTC.

METHODS

Based on weighted gene co-expression network analysis, Robust Rank Aggregation, functional annotation, GSEA and DNA methylation, were employed for investigating potential biomarkers for diagnosis of PTC.

RESULTS

Black and turquoise modules were identified in the gene co-expression network constructed by 1807 DEGs that from 6 eligible gene expression profiles of Gene Expression Omnibus database based on Robust Rank Aggregation and weighted gene co-expression network analysis. Hub genes were significantly down-regulated and the expression levels of the hub genes were different in different stages in hub gene verification. ROC curves indicated all hub genes had good diagnostic value for PTC (except for ABCA6 AUC = 89.5%, the 15 genes with AUC > 90%). Methylation analysis showed that hub gene verification ABCA6, ACACB, RMDN1 and TFPI were identified as differentially methylated genes, and the decreased expression level of these genes may relate to abnormal DNA methylation. Moreover, the expression levels of 8 top hub genes were correlated with tumor purity and tumor-infiltrating immune cells. These findings, including functional annotations and GSEA provide new insights into pathogenesis of PTC.

CONCLUSIONS

The hub genes and methylation of hub genes may as potential biomarkers provide new insights for diagnosis of PTC, and all these findings may be the direction to study the mechanisms underlying of PTC in the future.

Self-enforcing HMGB1/NF-κB/HIF-1α Feedback Loop Promotes Cisplatin Resistance in Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is ranked the sixth most common cancer and the fourth leading cause of cancer-related death worldwide, and its incidence is expected to increase in the future. Cisplatin has been widely used in chemotherapy and transarterial chemoembolization in treatment for HCC. However, the main obstacle to the clinical use of cisplatin is the development of resistance, the mechanisms of which are poorly defined. Therefore, it is imperative to investigate the cellular mechanisms mediating cisplatin resistance in HCC. Here, we demonstrated that high mobility group box 1 (HMGB1) is upregulated in patients with cancer, and implicated in a tumor-supportive role. Further, we showed that HMGB1 has an important role in mediating cisplatin resistance via an HMGB1/ nuclear factor kappa-B (NF-κB)/ hypoxia inducible factor-1α (HIF-1α) feedback loop. The study findings reveal an unappreciated molecular mechanism of HMGB1-mediated cisplatin resistance and may provide a new clue in cancer therapy.

Curcumol attenuates liver sinusoidal endothelial cell angiogenesis via regulating Glis-PROX1-HIF-1α in liver fibrosis

OBJECTIVE

Hepatic sinusoidal angiogenesis owing to dysfunctional liver sinusoidal endothelial cells (LSECs) accompanied by an abnormal angioarchitecture is a symbol related to liver fibrogenesis, which indicates a potential target for therapeutic interventions. However, there are few researches connecting angiogenesis with liver fibrosis, and the deeper mechanism remains to be explored.

MATERIALS AND METHODS

Cell angiogenesis and angiogenic protein were examined in primary LSECs of rats, and multifarious cellular and molecular assays revealed the efficiency of curcumol intervention in fibrotic mice.

RESULTS

We found that curcumol inhibited angiogenic properties through regulating their upstream mediator hypoxia-inducible factor-1α (HIF-1α). The transcription activation of HIF-1α was regulated by hedgehog signalling on the one hand, and the protein stabilization of HIF-1α was under the control of Prospero-related homeobox 1 (PROX1) on the other. A deubiquitinase called USP19 could be recruited by PROX1 and involved in ubiquitin-dependent degradation of HIF-1α. Furthermore, our researches revealed that hedgehog signalling participated in the activation of PROX1 transcription probably in vitro. Besides, curcumol was found to ameliorate liver fibrosis and sinusoid angiogenesis via hedgehog pathway in carbon tetrachloride (CCl₄ ) induced liver fibrotic mice. The protein expression of key regulatory factors, PROX1 and HIF-1α, was consistent with the Smo, the marker protein of Hh signalling pathway.

CONCLUSIONS

In this article, we evidenced that curcumol controlling LSEC-mediated angiogenesis could be a promising therapeutic approach for liver fibrosis.

Circular RNA circFOXM1 Plays a Role in Papillary Thyroid Carcinoma by Sponging miR-1179 and Regulating HMGB1 Expression

Circular RNAs (circRNAs) are a class of noncoding RNAs broadly expressed in cells of various species. However, the molecular mechanisms that link circRNAs with progression of papillary thyroid carcinoma (PTC) are not well understood. In the present study, we attempted to provide a novel basis for targeted therapy for PTC from the aspect of the circRNA-microRNA (miRNA)-mRNA interaction. We investigated the expression of circRNAs in five paired PTC tissues and normal tissues by microarray analysis. The circRNA microarray assay followed by qRT-PCR was used to verify the differential expression of circFOXM1 (hsa_circ_0025033), which is located at chr12: 2966846-2983691 and derived from FOXM1. The spliced length of circFOXM1 is 3410 nt. The qRT-PCR analysis was to investigate the expression pattern of circFOXM1 in PTC tissues and cell lines. Then, the effects of circFOXM1 on tumor growth were assessed in PTC in vitro and in vivo. Furthermore, bioinformatics online programs predicted, and the luciferase reporter assay was used to validate the association of circFOXM1 and miR-1179 in PTC cells. In this study, circFOXM1 was observed to be upregulated in PTC tissues and cell lines. circFOXM1 downregulation inhibited tumor growth of PTC in vitro and in vivo. Bioinformatics analysis predicted that there is a circFOXM1/miR-1179/high-mobility group box 1 (HMGB1) axis in PTC. A dual luciferase reporter system validated the direct interaction of circFOXM1, miR-1179, and HMGB1. In summary, our study demonstrated that circFOXM1 modulates cancer progression through the miR-1179/HMGB1 pathway in PTC. Our findings indicate that circFOXM1 may serve as a promising therapeutic target for the treatment of PTC patients.