HMGB2 promotes the malignancy of human gastric cancer and indicates poor survival outcome

Targeting high mobility group protein B2 exerts antiproliferative effects in hypoxic pulmonary hypertension by modulating miR-21

OBJECTIVE

Pulmonary hypertension (PH) is characterized by excessive vascular cell proliferation, leading to vascular remodeling. In this study, we aimed to investigate the molecular mechanisms underlying the regulation of vascular cell proliferation in the context of HMGB2 and its potential involvement in the pathogenesis of PH.

METHODS

Animals and pulmonary vascular smooth muscle cells (PASMCs) were exposed to hypoxia. Pathological changes in pulmonary vessels were detected by HE and Masson staining. The effect of HMGB2 on cell proliferation was detected by siRNA transfections and recombinant protein treatment. miR-21 inhibitor and mimics were applied, and TPM1 expression was detected. HMGB2-/- mice were applied to observe the possible preventive effect of HMGB2 in PH development.

RESULTS

HMGB2 expression was increased in hypoxic rats and PASMCs. Silencing ZDHHC5 reduced HMGB2 expression and cell proliferation. Cell proliferation was inhibited by knocking down HMGB2 and promoted by its over-expression. Hypoxia-induced miR-21 upregulation and TPM1 downregulation were mediated by HMGB2. 8-Br-cGMP suppressed HMGB2-induced PASMC proliferation and increased SOX2 expression by activating the cGMP/PKG signaling pathway. HMGB2-/- attenuated pulmonary vascular remodeling and fibrosis in hypoxia induced PH mice.

CONCLUSIONS

HMGB2 promotes PASMC proliferation through the cGMP/PKG-SOX2-miR-21-TPM1 pathway, which provides a new theoretical basis and possible targets for the pathogenesis and clinical prevention of PH.

Intratumoral Heterogeneity and Immune Microenvironment in Hepatoblastoma Revealed by Single-Cell RNA Sequencing

Hepatoblastoma (HB) is a common paediatric liver malignancy characterised by significant intratumoral heterogeneity and a complex tumour microenvironment (TME). Using single-cell RNA sequencing (scRNA-seq), we analysed 43,592 cells from three tumour regions and adjacent normal tissue of an HB patient. Our study revealed distinct cellular compositions and varying degrees of malignancy across different tumour regions, with the T1 region showing the highest malignancy and overexpression of HMGB2 and TOP2A. Survival analysis demonstrated that high HMGB2 expression is associated with poor prognosis and increased recurrence, suggesting its potential as a prognostic marker. Additionally, we identified a diverse immune microenvironment enriched with regulatory T cells (Tregs) and CD8+ effector memory T cells (Tem), indicating potential immune evasion mechanisms. Notably, CTLA-4 and PD-1 were highly expressed in Tregs and Tem cells, highlighting their potential as immunotherapy targets. Myeloid cells, including Kupffer cells and dendritic cells, also exhibited distinct functional roles in different tumour regions. This study provides the first comprehensive single-cell atlas of HB, revealing critical insights into its intratumoral heterogeneity and immune microenvironment. Our findings not only advance the understanding of HB biology but also offer new directions for precision medicine, including the development of targeted therapies and immunotherapeutic strategies to improve patient outcomes.

Bioinformatics analysis of coronary microvascular dysfunction in rats based on single-cell RNA sequencing

Coronary microvascular dysfunction serves as one of the etiological factors for ischemic heart disease and represents a novel therapeutic direction for coronary artery diseases; however, the research on its pathogenesis remains inconsistent. This study aims to explore the single-cell gene expression profiles in rats with coronary microvascular dysfunction using single-cell RNA sequencing, with a particular focus on the in-depth analysis of endothelial cell gene expression characteristics. By establishing a rat model of coronary microvascular dysfunction, we collected cardiac apical tissue to prepare single-cell suspensions and further analyzed them using bioinformatics methods. From a total of 55,419 cells, we identified 28 distinct cell clusters, with endothelial cells and fibroblasts being the predominant cell types. Compared to the NC group, the proportion of endothelial cells in the CMD group was significantly reduced, while the number of fibroblasts was significantly increased. Through further analysis of the endothelial cells, we classified them into normal phenotype endothelial cells, mesenchymal phenotype endothelial cells, proliferative phenotype endothelial cells, and lymphatic endothelial cells, with mesenchymal and proliferative endothelial cells originating from normal phenotype endothelial cells. Additionally, the CMD group exhibited an increase in immune cells, enhanced inflammatory response, and increased oxidative stress. These findings may provide novel potential therapeutic targets for the treatment of Coronary microvascular dysfunction.

Chronic stress-induced cholesterol metabolism abnormalities promote ESCC tumorigenesis and predict neoadjuvant therapy response

Recent studies have demonstrated that chronic stress can enhance the development of multiple human diseases, including cancer. However, the role of chronic stress in esophageal carcinogenesis and its underlying molecular mechanisms remain unclear. This study uncovered that dysregulated cholesterol metabolism significantly promotes esophageal carcinogenesis under chronic stress conditions. Our findings indicate that the persistent elevation of glucocorticoids induced by chronic stress stimulates cholesterol uptake, contributing to esophageal carcinogenesis. The activated glucocorticoid receptor (GCR) enrichment at the promoter region of High Mobility Group Box 2 (HMGB2) facilitates its transcription. As a transcription coactivator, HMGB2 enhances Sterol Regulatory Element Binding Transcription Factor 1 (SREBF1) transcription and regulates cholesterol metabolism through LDL particle uptake into cells via Low Density Lipoprotein Receptor (LDLR). These results emphasize the significant impact of chronic stress on esophageal carcinogenesis and establish cholesterol metabolism disorder as a crucial link between chronic stress and the development of ESCC. The implications suggest that effectively managing chronic stress may serve as a viable strategy for preventing and treating ESCC.

HMGB2 is a biomarker associated with poor prognosis promoting radioresistance in glioma by targeting base excision repair pathway

BACKGROUND

High mobility group box 2 (HMGB2) is considered as a biomarker of poor prognosis in various cancers.This study aims to investigate the effect and mechanism of HMGB2 in gliomas.

METHODS

With the glioma related on-line and our local hospital databases, the expression differences of HMGB2,Kaplan-Meier survival analysis and COX regression analysis were performed.The correlation analysis between the clinicopathological features and imaging parameters with the HMGB2 expression had been done. Then GSEA and PPI networks were carried out to find out the most significant pathway. The pathway inhibitor was applied to verify HMGB2's participation. CCK8,EDU assays,γ-H2AX immunofluorescence staining and colony formation assay were conducted to observe effects on glioma cells.

RESULTS

Available datasets showed that HMGB2 was highly expressed in glioma and patients with high expression of HMGB2 had poorer prognosis and molecular characteristics. Protein level evidence of western blot and immunohistochemistry from our center supported the conclusions above. Analysis on imaging features suggested that HMGB2 expression level had an inverse association with ADCmean but positively with the thickness of enhancing margin. Results from GSEA and PPI network analysis exhibited that HMGB2 was involved in base excision repair (BER) signaling pathway. Experimental evidence demonstrated that the overexpression of HMGB2 promoted the proliferation of glioma cells and enhanced the radio-resistance.

CONCLUSIONS

HMGB2 could promote glioma development and enhance the radioresistance of glioma cells, potentially related to the BER pathway, suggesting it may serve as an underlying biomarker for patients with glioma.

HMGB2 Release Promotes Pulmonary Hypertension and Predicts Severity and Mortality of Patients With Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary hypertension (PH) is a progressive and life-threatening disease characterized by pulmonary vascular remodeling, which involves aberrant proliferation and apoptosis resistance of the pulmonary arterial smooth muscle cells (PASMCs), resembling the hallmark characteristics of cancer. In cancer, the HMGB2 (high-mobility group box 2) protein promotes the pro-proliferative/antiapoptotic phenotype. However, the function of HMGB2 in PH remains uninvestigated.

METHODS

Smooth muscle cell (SMC)-specific HMGB2 knockout or HMGB2-OE (HMGB2 overexpression) mice and HMGB2 silenced rats were used to establish hypoxia+Su5416 (HySu)-induced PH mouse and monocrotaline-induced PH rat models, respectively. The effects of HMGB2 and its underlying mechanisms were subsequently elucidated using RNA-sequencing and cellular and molecular biology analyses. Serum HMGB2 levels were measured in the controls and patients with pulmonary arterial (PA) hypertension.

RESULTS

HMGB2 expression was markedly increased in the PAs of patients with PA hypertension and PH rodent models and was predominantly localized in PASMCs. SMC-specific HMGB2 deficiency or silencing attenuated PH development and pulmonary vascular remodeling in hypoxia+Su5416-induced mice and monocrotaline-treated rats. SMC-specific HMGB2 overexpression aggravated hypoxia+Su5416-induced PH. HMGB2 knockdown inhibited PASMC proliferation in vitro in response to PDGF-BB (platelet-derived growth factor-BB). In contrast, HMGB2 protein stimulation caused the hyperproliferation of PASMCs. In addition, HMGB2 promoted PASMC proliferation and the development of PH by RAGE (receptor for advanced glycation end products)/FAK (focal adhesion kinase)-mediated Hippo/YAP (yes-associated protein) signaling suppression. Serum HMGB2 levels were significantly increased in patients with PA hypertension, and they correlated with disease severity, predicting worse survival.

CONCLUSIONS

Our findings indicate that targeting HMGB2 might be a novel therapeutic strategy for treating PH. Serum HMGB2 levels could serve as a novel biomarker for diagnosing PA hypertension and determining its prognosis.

Blocking the E2F transcription factor 1/high-mobility group box 2 pathway enhances the intervention effects of α-santalol on the malignant behaviors of liver cancer cells

In view of the tumor-inhibiting effect of α-santalol in various cancers and the role of E2F transcription factor 1 (E2F1) as an important target for anticancer research, this study investigates the relation between α-santalol and E2F1, as well as the effect of α-santalol on liver cancer progression and the corresponding mechanism. Concretely, liver cancer cells were treated with different concentrations of α-santalol. The IC50 value of α-santalol was determined using Probit regression analysis. Then, transcription factors that are targeted by α-santalol and differentially expressed in liver cancer were screened out. The clinicopathological impact of E2F1 and its targets were evaluated and predicted. The expressions of E2F1 and high-mobility group box 2 (HMGB2) and their correlation in the liver cancer tissues were analyzed by bioinformatics. The effects of E2F1 and HMGB2 on the biological characteristics of liver cancer cells were examined through loss/gain-of-function and molecular assays. With the extension of treatment time, the inhibitory effects of 10 μmol/L and 20 μmol/L α-santalol on cancer cell survival rate were enhanced (P < 0.001). E2F1 and HMGB2 were highly expressed and positively correlated in liver cancer tissues (P < 0.05). High E2F1 expression was correlated with large tumors and high TNM stages (P < 0.05). E2F1 knockdown promoted the effects of α-santalol on dose-dependently inhibiting viability, colony formation, invasion and migration (P < 0.05). Moreover, E2F1 knockdown reduced the IC50 value and HMGB2 level, while HMGB2 overexpression produced opposite effects. HMGB2 overexpression and E2F1 knockdown mutually counteracted their effects on the IC50 value and on the viability and apoptosis of α-santalol-treated liver cancer cells (P < 0.01). Collectively, blocking the E2F1/HMGB2 pathway enhances the intervention effects of α-santalol on the proliferation, migration and invasion of liver cancer cells.

Energy metabolism: a new target for gastric cancer treatment

Gastric cancer is the fifth most common malignancy worldwide having the fourth highest mortality rate. Energy metabolism is key and closely linked to tumour development. Most important in the reprogramming of cancer metabolism is the Warburg effect, which suggests that tumour cells will utilise glycolysis even with normal oxygen levels. Various molecules exert their effects by acting on enzymes in the glycolytic pathway, integral to glycolysis. Second, mitochondrial abnormalities in the reprogramming of energy metabolism, with consequences for glutamine metabolism, the tricarboxylic acid cycle and oxidative phosphorylation, abnormal fatty acid oxidation and plasma lipoprotein metabolism are important components of tumour metabolism. Third, inflammation-induced oxidative stress is a danger signal for cancer. Fourth, patterns of signalling pathways involve all aspects of metabolic transduction, and many clinical drugs exert their anticancer effects through energy metabolic signalling. This review summarises research on energy metabolism genes, enzymes and proteins and transduction pathways associated with gastric cancer, and discusses the mechanisms affecting their effects on postoperative treatment resistance and prognoses of gastric cancer. We believe that an in-depth understanding of energy metabolism reprogramming will aid the diagnosis and subsequent treatment of gastric cancer.

MDIG in Breast Cancer Progression and Metastasis

Breast cancer is the most diagnosed cancer among women worldwide, and metastasis remains the major cause of breast cancer-related mortality and is associated with poor patient outcomes. Among breast cancers, triple-negative breast cancers have the worst prognosis owing to their highly aggressive and metastasizing attributes and hence have limited therapeutic options. Here, we have presented our research on an environmentally regulated gene named mdig and its role in the pathogenesis of breast cancer and metastasis. Through global proteomics, chromatin immunoprecipitation sequencing, and a mouse model of orthotopic xenograft, our studies established mdig as an anti-metastasis modulator in breast cancer with its influence on the methylation of DNA and histone proteins, thereby regulating the expression of genes implicated in epithelial-mesenchymal transitional, cell motility, and metastasis.

High-mobility group box 1 emerges as a therapeutic target for asthma

High-mobility group box 1 (HMGB1) is a highly conserved nonhistone nuclear protein found in the calf thymus and participates in a variety of intracellular processes such as DNA transcription, replication and repair. In the cytoplasm, HMGB1 promotes mitochondrial autophagy and is involved in in cellular stress response. Once released into the extracellular, HMGB1 becomes an inflammatory factor that triggers inflammatory responses and a variety of immune responses. In addition, HMGB1 binding with the corresponding receptor can activate the downstream substrate to carry out several biological effects. Meanwhile, HMGB1 is involved in various signaling pathways, such as the HMGB1/RAGE pathway, HMGB1/NF-κB pathway, and HMGB1/JAK/STAT pathway, which ultimately promote inflammation. Moreover, HMGB1 may be involved in the pathogenesis of asthma by regulating downstream signaling pathways through corresponding receptors and mediates a number of signaling pathways in asthma, such as HMGB1/TLR4/NF-κB, HMGB1/RAGE, HMGB1/TGF-β, and so forth. Accordingly, HMGB1 emerges as a therapeutic target for asthma.

Induction of perineural invasion in salivary adenoid cystic carcinoma by circular RNA RNF111

OBJECTIVE

Local recurrence, distant metastasis, and perineural invasion (PNI) viciously occur in salivary adenoid cystic carcinoma (SACC), resulting in a poor prognosis. This study aimed to explore the mechanism by which circular RNA RNF111 (circ-RNF111) regulates PNI in SACC by targeting the miR-361-5p/high mobility group box 2 (HMGB2) axis.

METHOD

Circ-RNF111 and HMGB2 were highly expressed in SACC specimens, while miR-361-5p was underexpressed. Functional experiments showed that ablating circ-RNF111 or promoting miR-361-5p hindered the biological functions and PNI of SACC-LM cells.

RESULTS

HMGB2 overexpression induced the reversal of SACC-LM cell biological functions and PNI caused by circ-RNF111 knockout. Furthermore, reduction of circ-RNF111 suppressed PNI in a SACC xenograft model. Circ-RNF111 regulated HMGB2 expression through targeted modulation of miR-361-5p.

CONCLUSION

Taken together, circ-RNF111 stimulates PNI in SACC by miR-361-5p/HMGB2 axis and may serve as a potential therapeutic target for SACC.

Role of non-coding RNAs as new therapeutic targets in regulating the EMT and apoptosis in metastatic gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC), are the two most common cancers of the gastrointestinal tract, and are serious health concerns worldwide. The discovery of more effective biomarkers for early diagnosis, and improved patient prognosis is important. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), can regulate cellular processes such as apoptosis and the epithelial-mesenchymal transition (EMT) leading to progression and resistance of GC and CRC tumors. Moreover these pathways (apoptosis and EMT) may serve as therapeutic targets, to prevent metastasis, and to overcome drug resistance. A subgroup of ncRNAs is common to both GC and CRC tumors, suggesting that they might be used as biomarkers or therapeutic targets. In this review, we highlight some ncRNAs that can regulate EMT and apoptosis as two opposite mechanisms in cancer progression and metastasis in GC and CRC. A better understanding of the biological role of ncRNAs could open up new avenues for the development of personalized treatment plans for GC and CRC patients.

HMGB family proteins: Potential biomarkers and mechanistic factors in cardiovascular diseases

Cardiovascular disease (CVD) is the most fatal disease that causes sudden death, and inflammation contributes substantially to its occurrence and progression. The prevalence of CVD increases as the population ages, and the pathophysiology is complex. Anti-inflammatory and immunological modulation are the potential methods for CVD prevention and treatment. High-Mobility Group (HMG) chromosomal proteins are one of the most abundant nuclear nonhistone proteins which act as inflammatory mediators in DNA replication, transcription, and repair by producing cytokines and serving as damage-associated molecular patterns in inflammatory responses. The most common and well-studied HMG proteins are those with an HMGB domain, which participate in a variety of biological processes. HMGB1 and HMGB2 were the first members of the HMGB family to be identified and are present in all investigated eukaryotes. Our review is primarily concerned with the involvement of HMGB1 and HMGB2 in CVD. The purpose of this review is to provide a theoretical framework for diagnosing and treating CVD by discussing the structure and function of HMGB1 and HMGB2.

The role of TRPV4 in the regulation of retinal ganglion cells apoptosis in rat and mouse

Retinal ganglion cell (RGC) damages are common in glaucoma, causing atrophy of the optic papilla, visual field damage, and visual loss. Transient receptor potential vanilloid 4 (TRPV4) is significantly expressed in the eyeball and is sensitive to mechanical and osmotic pressure. However, the specific role and mechanism of TRPV4 in glaucoma and RGC progression remain unclear. TRPV4 expression was detected in RGCs under different pressure culture conditions. We also explored the pressure effect on TRPV4 expression and the role and mechanism behind the functional regulation of RGCs. Immunofluorescence staining, western blotting, and TUNEL were utilized in this study. Our results established that TRPV4 was expressed in RGCs. TRPV4 expression was decreased at 40 mmHg and 60 mmHg, and the expression of BAX at 40 mmHg, 60 mmHg. Additionally, the expression of caspase 9 protein increased at 40 mmHg with the pressure increase compared with the conventional culture group. TUNEL staining revealed that the apoptosis rate of RGCs was elevated at 40 mmHg and 60 mmHg, compared with the traditional culture group. Therefore, the expression of BAX and caspase 9 increased, along with the apoptosis rate of RGCs compared with the control group. However, after TRPV4 antagonist treatment, the expression of BAX and caspase 9 decreased, and the apoptosis rate of RGCs decreased. Thus, TRPV4 may affect the mitochondrial apoptosis pathway, such as BAX and caspase 9, leading to the apoptosis of RGCs. The antagonists of TRPV4 could provide a new idea for clinically treating acute glaucoma.

Structure and Functions of HMGB2 Protein

High-Mobility Group (HMG) chromosomal proteins are the most numerous nuclear non-histone proteins. HMGB domain proteins are the most abundant and well-studied HMG proteins. They are involved in variety of biological processes. HMGB1 and HMGB2 were the first members of HMGB-family to be discovered and are found in all studied eukaryotes. Despite the high degree of homology, HMGB1 and HMGB2 proteins differ from each other both in structure and functions. In contrast to HMGB2, there is a large pool of works devoted to the HMGB1 protein whose structure-function properties have been described in detail in our previous review in 2020. In this review, we attempted to bring together diverse data about the structure and functions of the HMGB2 protein. The review also describes post-translational modifications of the HMGB2 protein and its role in the development of a number of diseases. Particular attention is paid to its interaction with various targets, including DNA and protein partners. The influence of the level of HMGB2 expression on various processes associated with cell differentiation and aging and its ability to mediate the differentiation of embryonic and adult stem cells are also discussed.

Expression, tumor immune infiltration, and prognostic impact of HMGs in gastric cancer

Background

In the past decade, considerable research efforts on gastric cancer (GC) have been expended, however, little advancement has been made owing to the lack of effective biomarkers and treatment options. Herein, we aimed to examine the levels of expression, mutations, and clinical relevance of HMGs in GC to provide sufficient scientific evidence for clinical decision-making and risk management.

Methods

GC samples were obtained from The Cancer Genome Atlas (TCGA). University of California Santa Cruz (UCSC) XENA, Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, STRING, LinkedOmics, and DAVID databases were employed. The "ggplot2" package in the R software (×64 3.6.3) was used to thoroughly analyze the effects of HMGs. qRT-PCR was performed to assess HMG levels in GC cell lines.

Results

A total of 375 GC tissues and 32 paraneoplastic tissues were analyzed. The levels of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN1, HMGN2, and HMGN4 expression were increased in GC tissues relative to normal gastric tissues. HMGA1, HMGA2, HMGB1, HMGB2, and HMGB3 were highly expressed in GC cell lines. The OS was significantly different in the group showing low expressions of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN2, HMGN3, and HMGN5. There was a significant difference in RFS between the groups with low HMGA2, HMGB3, and high HMGN2 expression. The levels of HMGA2, HMGB3, and HMGN1 had a higher accuracy for prediction to distinguish GC from normal tissues (AUC value > 0.9). HMGs were tightly associated with immune infiltration and tumor immune escape and antitumor immunity most likely participates in HMG-mediated oncogenesis in GC. GO and KEGG enrichment analyses showed that HMGs played a vital role in the cell cycle pathway.

Conclusions

Our results strongly suggest a vital role of HMGs in GC. HMGA2 and HMGB3 could be potential markers for prognostic prediction and treatment targets for GC by interrupting the cell cycle pathway. Our findings might provide renewed perspectives for the selection of prognostic biomarkers among HMGs in GC and may contribute to the determination of the optimal strategy for the treatment of these patients.

High level of LncRNA MAPKAPK5-AS1 predicts poor prognosis and contributes to the malignant proliferation and EMT of non-small cell lung cancer via sponging miR-490-3p from HMGB2

BACKGROUND

Patients with non-small cell lung cancer (NSCLC) show a low survival rate, owing to the lack of early diagnostic method and high invasiveness. Long non-coding RNA MAPKAPK5-AS1 that regulates tumor genesis and progression through multiple signals, is upregulated and involved in the growth and apoptosis in lung adenocarcinoma (LUAD).

OBJECTIVE

To investigate whether MAPKAPK5-AS1 affected the malignant progression of NSCLC.

METHODS

The levels of MAPKAPK5-AS1, miR-490-3p and HMGB2 in lung cancer were first analyzed through StarBase website, and confirmed by a quantitative reverse transcriptase-PCR (qRT-PCR) assay. The biological functions of NSCLC cells were examined by CCK-8, 5-ethynyl-2'-deoxyuridine (EdU) and flow cytometry assays. The potential binding sequences lncRNA-miRNA and miRNA-mRNA were predicted by StarBase software and verified via dual luciferase reporter experiment. The effects of MAPKAPK5-AS1 on tumor growth were evaluated in a xenografted mice model.

RESULTS

The expression of MAPKAPK5-AS1 was upregulated in tumor tissues from NSCLC patients. Patients with high expression of MAPKAPK5-AS1 had higher tumor size, advanced TNM stage, higher incidence of lymph node and distant metastasis, and shorter overall survival. Knockdown of MAPKAPK5-AS1 inhibited the proliferation, induced apoptosis and blocked epithelial mesenchymal transformation (EMT) of NSCLC cells. Mechanically, MAPKAPK5-AS1 could upregulate the HMGB2 level in NSCLC cells through competitively binding to miR-490-3p. MiR-490-3p inhibitor reversed the roles of MAPKAPK5-AS1 knockdown on tumor cell proliferation, apoptosis and EMT. Also, HMGB2 knockdown suppressed tumor cell malignant phenotypes. Furthermore, interference of MAPKAPK5-AS1 slowed NSCLC tumor growth in vivo.

CONCLUSION

Knockdown of MAPKAPK5-AS1 inhibited the aggressive tumor phenotypes through miR-490-3p/HMGB2 axis in NSCLC. MAPKAPK5-AS1/miR-490-3p/HMGB2 might be potential biomarkers or therapeutic targets for NSCLC.

Deletion of mdig enhances H3K36me3 and metastatic potential of the triple negative breast cancer cells

In this report, we provide evidence showing diminished expression of the mineral dust-induced gene (mdig), a previously identified oncogenic gene, in human triple negative breast cancer (TNBC). Using a mouse model of orthotopic xenograft of the TNBC MDA-MB-231 cells, we demonstrate that mdig promotes the growth of primary tumors but inhibits metastasis of these cells in vivo. Knockout of mdig resulted in an enhancement of H3K36me3 in the genome and upregulation of some X chromosome-linked genes for cell motility, invasion, and metastasis. Silencing MAGED2, one of the most upregulated and H3K36me3-enriched genes resulted from mdig depletion, can partially reverse the invasive migration of the mdig knockout cells. The anti-metastatic and inhibitory role of mdig on H3K36me3 was cross-validated in another cell line, A549 lung cancer cells. Together, our data suggest that mdig is antagonist against H3K36me3 that enforces expression of genes, such as MAGED2, for cell invasion and metastasis.

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Loss of mdig expression in TNBC and metastatic breast cancer

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Knockout of mdig enforces metastasis of the TNBC cells

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Mdig antagonizes H3K36me3 that promotes expression of X-linked metastatic genes

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Silencing MAGED2 reduces invasive migration of the mdig knockout cells

Long non-coding RNA NR2F2-AS1 regulates human osteosarcoma growth and metastasis through miR-425-5p-mediated HMGB2

BACKGROUND

Multiple studies have revealed that long non-coding RNA (lncRNA) NR2F2-AS1 plays a role in affecting cancer cell proliferation and metastasis. Here, both in vitro and in vivo experiments were performed for investigating the function and mechanism of NR2F2-AS1 in human osteosarcoma (OS).

METHODS

The NR2F2-AS1 level in human OS tissues and adjacent non-tumor tissues was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The NR2F2-AS1 overexpression model was constructed in OS cells, then cell proliferation, invasion, and apoptosis were monitored. The OS xenograft model was established in nude mice using NR2F2-AS1-overexpressed OS cells. The downstream target genes of NR2F2-AS1 were predicted. qRT-PCR and Western blot were implemented to validate the profiles of miR-425-5p and HMGB2. The targeting link between NR2F2-AS1 and miR-425-5p, miR-425-5p and HMGB2 was further probed by dual-luciferase reporter experiment.

RESULTS

In comparison to adjacent non-tumor tissues, OS tissues showed upregulated NR2F2-AS1 expression. Higher NR2F2-AS1 level was predominantly correlated with worse clinical stages. In vivo and in vitro tests corroborated that NR2F2-AS1 overexpression spurred OS cell proliferation, growth, invasion, and choked apoptosis. Mechanistically, NR2F2-AS1 hampered miR-425-5p expression as its competitive endogenous RNA (ceRNA). Thus, NR2F2-AS1 facilitated the HMGB2 expression. However, miR-425-5p inhibited HMGB2 expression by targeting the latter.

CONCLUSION

NR2F2-AS1 expedited the evolution of OS by elevating HMGB2 levels through sponging miR-425-5p. The NR2F2-AS1/miR-425-5p/HMGB2 regulatory axis is a promising target in treating human OS.

Epithelial-mesenchymal transition-related long noncoding RNAs in gastric carcinoma

As an evolutionarily phenotypic conversion program, the epithelial-mesenchymal transition (EMT) has been implicated in tumour deterioration and has facilitated the metastatic ability of cancer cells via enhancing migration and invasion. Gastric cancer (GC) remains a frequently diagnosed non-skin malignancy globally. Most GC-associated mortality can be attributed to metastasis. Recent studies have shown that EMT-related long non-coding RNAs (lncRNAs) play a critical role in GC progression and GC cell motility. In addition, lncRNAs are associated with EMT-related transcription factors and signalling pathways. In the present review, we comprehensively described the EMT-inducing lncRNA molecular mechanisms and functional perspectives of EMT-inducing lncRNAs in GC progression. Taken together, the statements of this review provided a clinical implementation in identifying lncRNAs as potential therapeutic targets for advanced GC.

Identification of HMGB2 associated with proliferation, invasion and prognosis in lung adenocarcinoma via weighted gene co-expression network analysis

Background

High mobility group protein B2 (HMGB2) is a multifunctional protein that plays various roles in different cellular compartments. Moreover, HMGB2 serves as a potential prognostic biomarker and therapeutic target for lung adenocarcinoma (LUAD).

Methods

In this study, the expression pattern, prognostic implication, and potential role of HMGB2 in LUAD were evaluated using the integrated bioinformatics analyses based on public available mRNA expression profiles from The Cancer Genome Atlas and Gene Expression Omnibus databases, both at the single-cell level and the tissue level. Further study in the patient-derived samples was conducted to explore the correlation between HMGB2 protein expression levels with tissue specificity, (tumor size-lymph node-metastasis) TNM stage, pathological grade, Ki-67 status, and overall survival. In vitro experiments, such as CCK-8, colony-formation and Transwell assay, were performed with human LUAD cell line A549 to investigate the role of HMGB2 in LUAD progression. Furthermore, xenograft tumor model was generated with A549 in nude mice.

Results

The results showed that the HMGB2 expression was higher in the LUAD samples than in the adjacent normal tissues and was correlated with high degree of malignancy in different public data in this study. Besides, over-expression of HMGB2 promoted A549 cells proliferation and migration while knocking down of HMGB2 suppressed the tumor promoting effect.

Conclusions

Our study indicated that HMGB2 was remarkably highly expressed in LUAD tissues, suggesting that it is a promising diagnostic and therapeutic marker for LUAD in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02110-y.

Tumor-Infiltrated CD8+ T Cell 10-Gene Signature Related to Clear Cell Renal Cell Carcinoma Prognosis

Clear cell renal cell carcinoma (ccRCC) usually affects multiple organs (e.g., bone and brain), and patient prognosis is usually poor. Although it is known that CD8+ T cell infiltration can potentially alleviate ccRCC progression, few studies have concentrated on the correlation between CD8+ T cell infiltration and ccRCC prognosis. In this study, ten genes expressed by infiltrated CD8+ T cells (i.e., AMD1, CCSER2, CIB1, DRAP1, HMGB2, HMGN1, NPIPB5, PTP4A2, RORA, and SAP18) were suggested as potential ccRCC prognostic biomarkers, by using next-generation sequencing (i.e. bulk sequencing and single-cell sequencing) of ccRCC, papillary renal cell carcinoma (papRCC), and control kidney biopsies. Specifically, we identified four genes (i.e., CCSER2, DRAP1, NPIPB5, and SAP18) as potential novel prognostic biomarkers for ccRCC. It is noteworthy that SAP18 derived from CD8+ T cells negatively correlates to Atg7+ neutrophils in ccRCC, compared with papRCC, indicating a potential decreased neutrophil metabolic function in autophagy and fatty acids. This study elucidated the protective role of infiltrated CD8+ T cells in ccRCC and identified ten candidate genes related to an improved prognosis in patients with ccRCC.

The Seasonal and Stage-Specific Expression Patterns of HMGB2 Suggest Its Key Role in Spermatogenesis in the Chinese Soft-Shelled Turtle (Pelodiscus sinensis)

HMGB2, a member of the high-mobility group (HMG) proteins, was identified as a male-biased gene and plays a crucial role in the germ cells differentiation of mammals. However, its role in spermatogenesis of turtle is still poorly understood. Here, we cloned the Pelodiscus sinensis HMGB2 and analyzed its expression profile in different tissues and in testis at different developmental ages. P. sinensis HMGB2 mRNA was highly expressed in the testis of 3-year-old turtles (P < 0.01), but was hardly detected in ovaries and other somatic tissues. The results of chemical in situ hybridization (CISH) showed that HMGB2 mRNA was specifically expressed in germ cells, where it was mainly distributed in round spermatids and sperm, but not detected in somatic cells, spermatogonia, primary spermatocytes, or secondary spermatocyte. The relative expression of HMGB2 also responded to seasonal changes in testis development in P. sinensis. In different seasons of the year, the relative expression of HMGB2 transcripts in the testis of 1 year and 2 year olds showed an overall upward trend, whereas, in the testis of 3 year old, it peaked in July and then declined in October. Moreover, in April and July, with an increase in ages, the expression of HMGB2 transcripts showed an upward trend. However, in January and October, there was a decline in expression in testis in 3-year-old turtles. These results showed that HMGB2 is closely related to spermatogenesis in P. sinensis.

Circular RNA circ_UBAP2 facilitates the progression of osteosarcoma by regulating microRNA miR-637/high-mobility group box (HMGB) 2 axis

Circular RNA circ_UBAP2 has been reported to be closely associated with various tumors. The present work focused on exploring the roles of circ_UBAP2 and its molecular mechanism in osteosarcoma (OS). Circ_UBAP2, miR-637, and high-mobility group box (HMGB) 2 levels in OS cells and tissues were detected by quantitative real-time polymerase chain reaction. The relationship between miR-637 and circ_UBAP2, as well as between miR-637 and HMGB2, was predicted and examined through bioinformatics analysis and luciferase reporter gene experiments. Moreover, OS cell growth, invasion, migration, and apoptosis were detected using the cell counting kit-8 (CCK-8), Transwell and flow cytometry assays, respectively. HMGB2 protein levels were measured using Western blotting. Xenograft tumor formation assay was also performed. Circ_UBAP2 showed high expression levels in OS tissues and cells, which was directly proportional to metastasis and clinical stage of OS. The overexpression of circ_UBAP2 enhanced the growth, invasion, and migration of OS cells, but suppressed their apoptosis. In contrast, circ_UBAP2 silencing had opposite effects. Furthermore, miR-637 served as a downstream target of circ_UBAP2, which played opposite roles to circ_UBAP2 in OS. More importantly, HMGB2 served as miR-637's downstream target. The xenograft experiments in nude mice also proved that knockdown of circ_UBAP2 could increase miR-637 expression, but decrease HMGB2 expression, thus alleviating OS progression. Mechanistically, circ_UBAP2 exerts a cancer-promoting effect on OS by downregulating miR-637 and upregulating the expression of HMGB2. Circ_UBAP2 plays a promoting role in OS, and the circ_UBAP2/miR-637/HMGB2 axis is involved in OS progression.

Centromere protein U (CENPU) promotes gastric cancer cell proliferation and glycolysis by regulating high mobility group box 2 (HMGB2)

Gastric cancer is one of the most common malignancy with a leading mortality rate worldwide. Despite the progress in the diagnosis and therapeutic strategy, the associated mortality is still growing. It is of great significance to understand molecular mechanisms of the development of gastric cancer. Glycolysis is a main source of ATP provision for cancer cells including gastric cancer, and targeting glycolysis is a promising therapeutic strategy. Centromere protein U (CENPU) has been found to be overexpressed in many types of cancer. Downregulation of CENPU suppresses the proliferation and invasion of cancer cells. High mobility group box 2 (HMGB2) is identified as a biomarker to diagnose of gastric cancer. Knockdown of HMGB2 inhibits proliferation and glycolysis in gastric cancer cells. In this work, we identified that CENPU was upregulated in gastric cancer. Knockdown of CENPU was able to suppress the proliferation and glycolysis of gastric cancer cells. Further the results showed that the anti-cancer effect of CENPU was HMGB2-dependent. Taken together, CENPU is an upstream factor of HMGB2, which regulates proliferation and glycolysis of gastric cancer.

Roles of HMGBs in Prognosis and Immunotherapy: A Pan-Cancer Analysis

Background: High mobility group box (HMGB) proteins are DNA chaperones involved in transcription, DNA repair, and genome stability. Extracellular HMGBs also act as cytokines to promote inflammatory and immune responses. Accumulating evidence has suggested that HMGBs are implicated in cancer pathogenesis; however, their prognostic and immunological values in pan-cancer are not completely clear. Methods: Multiple tools were applied to analyze the expression, genetic alternations, and prognostic and clinicopathological relevance of HMGB in pan-cancer. Correlations between HMGB expression and tumor immune-infiltrating cells (TIICs), immune checkpoint (ICP) expression, microsatellite instability (MSI), and tumor mutational burden (TMB) in pan-cancer were investigated to uncover their interactions with the tumor immune microenvironment (TIME). Gene set enrichment analysis (GSEA) was conducted for correlated genes of HMGBs to expound potential mechanisms. Results: HMGB expression was significantly elevated in various cancers. Both prognostic and clinicopathological significance was observed for HMGB1 in ACC; HMGB2 in ACC, LGG, LIHC, and SKCM; and HMGB3 in ESCA. Prognostic values were also found for HMGB2 in KIRP and MESO and HMGB3 in BRCA, SARC, SKCM, OV, and LAML. The global alternation of HMGBs showed prognostic significance in ACC, KIRC, and UCEC. Furthermore, HMGBs were significantly correlated with TIIC infiltration, ICP expression, MSI, and TMB in various cancers, indicating their regulations on the TIME. Lastly, results of GSEA-illuminated genes positively correlated with HMGBs which were similarly chromosome components participating in DNA activity-associated events. Conclusion: This study demonstrated that HMGBs might be promising predictive biomarkers for the prognosis and immunotherapeutic response, also immunotherapy targets of multiple cancers.

CircLPAR3 Acts as an Oncogene in Oral Squamous Cell Carcinoma Through Regulating the miR-643/HMGB2 Network

The malignant progression of oral squamous cell carcinoma (OSCC) has been confirmed to be mediated by a variety of factors, including circular RNA (circRNA). However, the role of circLPAR3 in OSCC development is still unclear. 70 paired OSCC tissues and normal control tissues were obtained from 70 OSCC patients. Quantitative real-time PCR was used to detect the expression of circLPAR3, microRNA (miR)-643, and high-mobility group box 2 (HMGB2). Cell proliferation, apoptosis, metastasis and stemness were assessed using cell counting kit 8 assay, colony-formation assay, flow cytometry, transwell assay and sphere formation assay. Marker protein expression and HMGB2 protein expression were determined by western blot analysis. The interaction between miR-643 and circLPAR3 or HMGB2 was confirmed by RNA pull-down assay, dual-luciferase reporter and RIP assay. The role of circLPAR3 in OSCC tumorigenesis was explored by constructing the xenograft models. Our data showed that circLPAR3 was highly expressed in OSCC tissues and cells. CircLPAR3 silencing suppressed OSCC cell proliferation, metastasis and stemness, while promoted apoptosis. On the mechanism, we discovered that circLPAR3 could sponge miR-643 to positive regulate HMGB2. MiR-643 overexpression had an inhibition effect on OSCC progression, and its inhibitor could reverse the negative regulation of circLPAR3 knockdown on OSCC progression. In addition, overexpressed HMGB2 also reversed the suppressive effect of circLPAR3 silencing on OSCC progression. Animal experiments results showed that downregulated circLPAR3 repressed OSCC tumorigenesis in vivo. Taken together, our data showed that circLPAR3 contributed to OSCC malignant progression through regulating the miR-643/HMGB2 axis.

HDAC3 increases HMGB3 expression to facilitate the immune escape of breast cancer cells via down-regulating microRNA-130a-3p

OBJECTIVE

Histone deacetylase 3 (HDAC3) has been reported to repress the expression of various genes by eliminating acetyl group from histone. The objective of this study was to discuss the effect of HDAC3/microRNA-130a-3p (miR-130a-3p)/high-mobility group box 3 (HMGB3) on immune escape of breast cancer.

METHODS

HDAC3, miR-130a-3p and HMGB3 expression in breast cancer tissues and cells were tested, and the correlation between HDAC3, miR-130a-3p and HMGB3 was analyzed. CD8, CD69 and programmed cell death protein 1 (PD-1) expression was detected. MDA-MB-231 cells were treated with relative plasmid of HDAC3 or miR-130a-3p to test cell viability, migration, epithelial-mesenchymal transition (EMT) and apoptosis in MDA-MB-231 cells. The cytotoxicity of CD8+/CD69+/PD-1+T cells in MDA-MB-231 cells was tested, and CD8+/CD69+/PD-1+T cell proliferation and apoptosis before and after co-culture with MDA-MB-231 cells were detected.

RESULTS

HDAC3 and HMGB3 expression were raised and miR-130a-3p expression was diminished in breast cancer tissues and cells. HDAC3 was negatively correlated with miR-130a-3p while miR-130a-3p was negatively correlated with HMGB3. Down-regulating HDAC3 or up-regulating miR-130a-3p restrained cell viability, migration, EMT and anti-CD8+/CD69+/PD-1+T cytotoxicity and facilitated apoptosis of breast cancer cells. HDAC3 regulated HMGB3 by mediating miR-130a-3p expression. Down-regulating miR-130a-3p reversed the role of HDAC3 reduction on breast cancer cells. HDAC3 regulated CD8+/CD69+/PD-1+T cell proliferation and apoptosis by mediating miR-130a-3p.

CONCLUSION

This study provides evidence that HDAC3 increases HMGB3 expression to promote the immune escape of breast cancer cells via down-regulating miR-130a-3p.

High-mobility group box 2 reflects exacerbated disease characteristics and poor prognosis in non-small cell lung cancer patients

BACKGROUND

High-mobility group box 2 (HMGB2) is considered as oncogene in non-small cell lung cancer (NSCLC), while its clinical implication is still unknown. This study aimed to explore the correlation of HMGB2 with clinicopathological characteristics and prognosis in NSCLC patients.

METHODS

A total of 133 NSCLC patients who received radical excision were enrolled. HMGB2 expression in the tumor specimens and paired adjacent tissue specimens was determined by immunohistochemical assay (for protein expression) and reverse transcription quantitative polymerase chain reaction assay (for gene expression), respectively.

RESULTS

HMGB2 protein expression was higher in tumor tissue compared with adjacent tissue, and it could distinguish tumor tissue from adjacent tissue (area under the curve (AUC): 0.775, 95%confidence interval (95%CI): 0.720-0.830). Meanwhile, tumor HMGB2 protein high expression correlated with lymph node (LYN) metastasis and advanced TNM stage. Additionally, tumor HMGB2 protein high expression associated with worse disease-free survival (DFS), while HMGB2 protein expression did not correlate with overall survival (OS). Besides, HMGB2 mRNA expression was raised in tumor tissue compared with adjacent tissue, and it had a good value in differentiating tumor tissue from adjacent tissue (AUC: 0.875, 95% CI: 0.834-0.915). Furthermore, tumor HMGB2 mRNA high expression correlated with higher Eastern Cooperative Oncology Group performance status score, LYN metastasis, and advanced TNM stage. Meanwhile, tumor HMGB2 mRNA high expression associated with shorter DFS and OS.

CONCLUSION

HMGB2 could be a biomarker that reflects disease features and prognosis of NSCLC, which is beneficial to improve clinical efficacy in NSCLC patients.

Tumor promoting long non-coding RNA CASC15 affects HMGB2 expression by sponging miR-582-5p in colorectal cancer

BACKGROUND

The importance of long non-coding RNAs (lncRNAs) in regulating tumorigenesis has been gradually recognized. Roles of lncRNA cancer susceptibility candidate 15 (CASC15) in cancers have been validated by several independent groups, however, its role in colorectal cancer (CRC) remains to be explored.

METHODS

Levels of CASC15 in CRC cells and normal cells were measured with the qRT-PCR method. In vitro functional assays were performed to detect the effects of CASC15 on cell proliferation, invasion, and apoptosis. Bioinformatic analyses and luciferase activity assays were conducted to investigate the targets for CASC15. Animal experiments were conducted to analyze the effect of CASC15 on tumor growth in vivo.

RESULTS

CASC15 level is revealed to be significantly elevated in CRC cells compared with normal cells. In vitro assays revealed that CASC15 overexpression stimulates cell growth and invasion, while its down-expression has opposite effects. Furthermore, CASC15 can bind with microRNA-582-5p (miR-582-5p) to modulate high mobility group box 2 (HMGB2) expression. We also showed that silencing of CASC15 inhibits tumor growth.

CONCLUSIONS

In summary, CASC15 overexpression could promote CRC carcinogenesis, indicating knockdown of CASC15 might be a possible therapeutic measure to hinder carcinogenesis. This work could help us to understand the mechanisms behind CRC progression.

Biological functions and theranostic potential of HMGB family members in human cancers

The high mobility group box (HMGB) protein family consists of four members: HMGB1, 2, 3, and 4. They share similar amino acid sequences and identical functional regions, especially HMGB1, 2, and 3. The homology in structure may lead to similarity in function. In fact, though their targets may be different, they all possess the fundamental function of binding and distorting target DNAs. However, further research confirmed they are distributed differently in tissues and involved in various distinct physiological and pathological cellular processes, including cell proliferation, division, migration, and differentiation. Recently, the roles of HMGB family members in carcinogenesis has been widely investigated; however, systematic discussion on their functions and clinical values in malignant tumors is limited. In this review, we mainly review and summarize recent advances in knowledge of HMGB family members in terms of structure, distribution, biochemical cascades, and specific mechanisms regarding tumor progression. Importantly, the diagnostic, prognostic, and therapeutic value of these proteins in cancers is discussed. Finally, we envisage the orientation and challenges of this field in further studies.

Nonhistone Proteins HMGB1 and HMGB2 Differentially Modulate the Response of Human Embryonic Stem Cells and the Progenitor Cells to the Anticancer Drug Etoposide

HMGB1 and HMGB2 proteins are abundantly expressed in human embryonic stem cells (hESCs) and hESC-derived progenitor cells (neuroectodermal cells, hNECs), though their functional roles in pluripotency and the mechanisms underlying their differentiation in response to the anticancer drug etoposide remain to be elucidated. Here, we show that HMGB1 and/or HMGB2 knockdown (KD) by shRNA in hESCs did not affect the cell stemness/pluripotency regardless of etoposide treatments, while in hESC-derived neuroectodermal cells, treatment resulted in differential effects on cell survival and the generation of rosette structures. The objective of this work was to determine whether HMGB1/2 proteins could modulate the sensitivity of hESCs and hESC-derived progenitor cells (hNECs) to etoposide. We observed that HMGB1 KD knockdown (KD) and, to a lesser extent, HMGB2 KD enhanced the sensitivity of hESCs to etoposide. Enhanced accumulation of 53BP1 on telomeres was detected by confocal microscopy in both untreated and etoposide-treated HMGB1 KD hESCs and hNECs, indicating that the loss of HMGB1 could destabilize telomeres. On the other hand, decreased accumulation of 53BP1 on telomeres in etoposide-treated HMGB2 KD hESCs (but not in HMGB2 KD hNECs) suggested that the loss of HMGB2 promoted the stability of telomeres. Etoposide treatment of hESCs resulted in a significant enhancement of telomerase activity, with the highest increase observed in the HMGB2 KD cells. Interestingly, no changes in telomerase activity were found in etoposide-treated control hNECs, but HMGB2 KD (unlike HMGB1 KD) markedly decreased telomerase activity in these cells. Changes in telomerase activity in the etoposide-treated HMGB2 KD hESCs or hNECs coincided with the appearance of DNA damage markers and could already be observed before the onset of apoptosis. Collectively, we have demonstrated that HMGB1 or HMGB2 differentially modulate the impact of etoposide treatment on human embryonic stem cells and their progenitor cells, suggesting possible strategies for the enhancement of the efficacy of this anticancer drug.

Long Noncoding RNA PART1 Promotes Hepatocellular Carcinoma Progression via Targeting miR-590-3p/HMGB2 Axis

Introduction

In East Asia, hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancer types. Long noncoding RNA (lncRNA) prostate androgen-regulated transcript 1 (PART1) was reported to play crucial roles in regulating cancer progression. However, roles and mechanisms of action of PART1 in hepatocellular carcinoma (HCC) still remain unknown.

Methods

Quantitative real-time polymerase chain reaction (RT-qPCR) method was used to detect the PART1 expression level in HCC cells. Cell proliferation, colony formation, and transwell invasion assays were performed to investigate the biological roles of PART1 on HCC cell behaviors. Bioinformatic analysis methods were performed to analyze connections of microRNA-590-3p (miR-590-3p) with PART1 or high mobility group box 2 (HMGB2) in HCC. Moreover, expression levels of PART1, miR-590-3p, and HMGB2 in HCC tissues and normal tissues were analyzed at ENCORI.

Results

PART1 expression was found to be significantly upregulated in HCC tissues and cells. Functionally, silencing of PART1 significantly suppressed HCC cell proliferation, colony formation and invasion in vitro, while forcing PART1 exerts opposite biological effects. Mechanically, miR-590-3p/HMGB2 axis was downstream target of PART1, and silencing of miR-590-3p or forcing of HMGB2 could rescue the stimulation effects of PART1 overexpression on HCC cell behaviors.

Discussion

Our results provided evidence that PART1 serves as oncogenic lncRNA through sponging miR-590-3p to upregulate HMGB2 expression in HCC.

High mobility group box 2 modulates the progression of osteosarcoma and is related with poor prognosis

Background

Increased expression of high mobility group box 2 (HMGB2) has been reported to promote the progression of several malignancies and be related to poor outcome. However, few studies have explored the relationship between HMGB2 and osteosarcoma. In this study, we aimed to obtain a better understanding of HMGB2 and its function in osteosarcoma.

Methods

Utilizing osteosarcoma paraffin sections and osteosarcoma cell lines, we observed the clinico-pathological relationship of osteosarcoma with HMGB2 expression and investigated the functions of HMGB2 in vitro. The possible pathways and regulation networks in which HMGB2 is involved were further explored through analysis of miRNA, mRNA and lncRNA micro array data sets.

Results

Strong expression of HMGB2 was found to be related with Enneking staging (P=0.002), tumor size (P=0.006), metastasis (P<0.001), and survival (P=0.011) in osteosarcoma. Multivariate analysis revealed that HMGB2 might have independent prognostic value in osteosarcoma (P=0.022). Kaplan-Meier curves and the log-rank test showed that survival time was significantly reduced in OS patients with strong HMGB2 expression (P=0.0056). In vitro experiments showed that HMGB2 overexpression promoted cell proliferation and enhanced the migration and invasion ability of osteosarcoma cells. Gene Ontology (GO) term analysis of osteosarcoma cell lines revealed HMGB2 to have various functions and to be mainly enriched in regulation of cell proliferation, cell death, and DNA binding. A competing endogenous RNA (ceRNA) network of miR-139-5p and six candidate lncRNAs was also suggested as targeting HMGB2 in osteosarcoma.

Conclusions

Our findings suggest that HMGB2 might have various functions in promoting the progression of osteosarcoma and may serve as a new target for osteosarcoma research.

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.

Targeting Chromosomal Architectural HMGB Proteins Could Be the Next Frontier in Cancer Therapy

Chromatin-associated architectural proteins are part of a fundamental support system for cellular DNA-dependent processes and can maintain/modulate the efficiency of DNA replication, transcription, and DNA repair. Interestingly, prognostic outcomes of many cancer types have been linked with the expression levels of several of these architectural proteins. The high mobility group box (HMGB) architectural protein family has been well studied in this regard. The differential expression levels of HMGB proteins and/or mRNAs and their implications in cancer etiology and prognosis present the potential of novel targets that can be explored to increase the efficacy of existing cancer therapies. HMGB1, the most studied member of the HMGB protein family, has pleiotropic roles in cells including an association with nucleotide excision repair, base excision repair, mismatch repair, and DNA double-strand break repair. Moreover, the HMGB proteins have been identified in regulating DNA damage responses and cell survival following treatment with DNA-damaging agents and, as such, may play roles in modulating the efficacy of chemotherapeutic drugs by modulating DNA repair pathways. Here, we discuss the functions of HMGB proteins in DNA damage processing and their potential roles in cancer etiology, prognosis, and therapeutics.

HMGB2 is a negative regulator of telomerase activity in human embryonic stem and progenitor cells

High-mobility group box (HMGB)1 and HMGB2 proteins are the subject of intensive research because of their involvement in DNA replication, repair, transcription, differentiation, proliferation, cell signaling, inflammation, and tumor migration. Using inducible, stably transfected human embryonic stem cells (hESCs) capable of the short hairpin RNA-mediated knockdown (KD) of HMGB1 and HMGB2, we provide evidence that deregulation of HMGB1 or HMGB2 expression in hESCs and their differentiated derivatives (neuroectodermal cells) results in distinct modulation of telomere homeostasis. Whereas HMGB1 enhances telomerase activity, HMGB2 acts as a negative regulator of telomerase activity in the cell. Stimulation of telomerase activity in the HMGB2-deficient cells may be related to activation of the PI3K/protein kinase B/ glycogen synthase kinase-3β/β-catenin signaling pathways by HMGB1, augmented TERT/telomerase RNA subunit transcription, and possibly also because of changes in telomeric repeat-containing RNA (TERRA) and TERRA-polyA⁺ transcription. The impact of HMGB1/2 KD on telomerase transcriptional regulation observed in neuroectodermal cells is partially masked in hESCs by their pluripotent state. Our findings on differential roles of HMGB1 and HMGB2 proteins in regulation of telomerase activity may suggest another possible outcome of HMGB1 targeting in cells, which is currently a promising approach aiming at increasing the anticancer activity of cytotoxic agents.-Kučírek, M., Bagherpoor, A. J., Jaroš, J., Hampl, A., Štros, M. HMGB2 is a negative regulator of telomerase activity in human embryonic stem and progenitor cells.

Bioinformatics analysis of the prognosis and biological significance of HMGB1, HMGB2, and HMGB3 in gastric cancer

High mobility group box (HMGB) consists primarily of HMGB1, HMGB2, and HMGB3 proteins. Although abnormal HMGB expression is associated with various tumors, the relationship with gastric cancer (GC) remains unclear. In this study, HMGB1, HMGB2, and HMGB3 expression was analyzed using the Oncomine and TCGA databases. Correlations between HMGB1, HMGB2, and HMGB3 and clinicopathological factors were analyzed. cBioPortal was used to analyze HMGB1, HMGB2, and HMGB3 genetic alterations and its gene regulation network in GC tissue. HMGB1, HMGB2, and HMGB3 expression was higher in tumor tissues than in normal tissues, especially in GC. High HMGB1, HMGB2, and HMGB3 expression may predict a poor prognosis among patients with GC (hazard ratios [HR] = 1.90; 95% confidence interval [CI]: [1.30-2.78]) and human digestive system neoplasm (HR = 1.85; 95% CI [1.64-2.10]). These findings suggest that HMGB1, HMGB2, and HMGB3 may be useful prognostic indicators for patients with GC.

Incorporating molecular biomarkers into clinical practice for gastric cancer

Introduction: Gastric cancer is one of the most common causes of cancer-related mortality worldwide. To improve clinical outcomes, it is critical to develop appropriate approaches to diagnosis and treatment. Biomarkers have numerous potential clinical applications, including screening, assessing risk, determining prognosis, monitoring recurrence, and predicting response to treatment. Furthermore, biomarkers may contribute to the development of effective therapies. Areas covered: Here we review recent progress in exploiting GC-specific biomarkers such as protein-coding genes, microRNAs, long noncoding RNAs, and methylated gene promoters. Expert opinion: The development of biomarkers for diagnosing and monitoring gastric cancer and for individualizing therapeutic targets shows great promise for improving gastric cancer management.

KLF8 is associated with poor prognosis and regulates glycolysis by targeting GLUT4 in gastric cancer

Krüppel‐like transcription factor (KLF) family is involved in tumorigenesis in different types of cancer. However, the importance of KLF family in gastric cancer is unclear. Here, we examined KLF gene expression in five paired liver metastases and primary gastric cancer tissues by RT‐PCR, and immunohistochemistry was used to study KLF8 expression in 206 gastric cancer samples. The impact of KLF8 expression on glycolysis, an altered energy metabolism that characterizes cancer cells, was evaluated. KLF8 showed the highest up‐regulation in liver metastases compared with primary tumours among all KLF members. Higher KLF8 expression associated with larger tumour size (P < 0.001), advanced T stage (P = 0.003) and N stage (P < 0.001). High KLF8 expression implied shorter survival outcome in both TCGA and validation cohort (P < 0.05). Silencing KLF8 expression impaired the glycolysis rate of gastric cancer cells in vitro. Moreover, high KLF8 expression positively associated with SUVmax in patient samples. KLF8 activated the GLUT4 promoter activity in a dose‐dependent manner (P < 0.05). Importantly, KLF8 and GLUT4 showed consistent expression patterns in gastric cancer tissues. These findings suggest that KLF8 modulates glycolysis by targeting GLUT4 and could serve as a novel biomarker for survival and potential therapeutic target in gastric cancer.