Overexpression of high mobility group protein B1 correlates with the proliferation and metastasis of lung adenocarcinoma cells

Role of HMGB1 and its associated signaling pathways in human malignancies

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

Downregulation of angulin-1/LSR induces malignancy via upregulation of EGF-dependent claudin-2 and TGF-β-dependent cell metabolism in human lung adenocarcinoma A549 cells

Abnormal expression of bicellular tight junction claudins, including claudin-2 are observed during carcinogenesis in human lung adenocarcinoma. However, little is known about the role of tricellular tight junction molecule angulin-1/lipolysis-stimulated lipoprotein receptor (LSR). In the lung adenocarcinoma tissues examined in the present study, expression of claudin-2 was higher than in normal lung tissues, while angulin-1/LSR was poorly or faintly expressed. We investigated how loss of angulin-1/LSR affects the malignancy of lung adenocarcinoma cell line A549 and normal human lung epithelial (HLE) cells. The EGF receptor tyrosine kinase inhibitor AG1478 prevented the increase of claudin-2 expression induced by EGF in A549 cells. Knockdown of LSR induced expression of claudin-2 at the protein and mRNA levels and AG1478 prevented the upregulation of claudin-2 in A549 cells. Knockdown of LSR induced cell proliferation, cell migration and cell metabolism in A549 cells. Knockdown of claudin-2 inhibited the cell proliferation but did not affect the cell migration or cell metabolism of A549 cells. The TGF-β type I receptor inhibitor EW-7197 prevented the decrease of LSR and claudin-2 induced by TGF-β1 in A549 cells and 2D culture of normal HLE cells. EW-7197 prevented the increase of cell migration and cell metabolism induced by TGF-β1 in A549 cells. EW-7197 prevented the increase of epithelial permeability of FITC-4kD dextran induced by TGF-β1 in 2.5D culture of normal HLE cells. In conclusion, downregulation of angulin-1/LSR induces malignancy via EGF-dependent claudin-2 and TGF-β-dependent cell metabolism in human lung adenocarcinoma.

Proteomic analysis of brain metastatic lung adenocarcinoma reveals intertumoral heterogeneity and specific alterations associated with the timing of brain metastases

BACKGROUND

Brain metastases are associated with considerable negative effects on patients' outcome in lung adenocarcinoma (LADC). Here, we investigated the proteomic landscape of primary LADCs and their corresponding brain metastases.

MATERIALS AND METHODS

Proteomic profiling was conducted on 20 surgically resected primary and brain metastatic LADC samples via label-free shotgun proteomics. After sample processing, peptides were analyzed using an Ultimate 3000 pump coupled to a QExactive HF-X mass spectrometer. Raw data were searched using PD 2.4. Further data analyses were carried out using Perseus, RStudio and GraphPad Prism. Proteomic data were correlated with clinical and histopathological parameters and the timing of brain metastases. Mass spectrometry-based proteomic data are available via ProteomeXchange with identifier PXD027259.

RESULTS

Out of the 6821 proteins identified and quantified, 1496 proteins were differentially expressed between primary LADCs and corresponding brain metastases. Pathways associated with the immune system, cell-cell/matrix interactions and migration were predominantly activated in the primary tumors, whereas pathways related to metabolism, translation or vesicle formation were overrepresented in the metastatic tumors. When comparing fast- versus slow-progressing patients, we found 454 and 298 differentially expressed proteins in the primary tumors and brain metastases, respectively. Metabolic reprogramming and ribosomal activity were prominently up-regulated in the fast-progressing patients (versus slow-progressing individuals), whereas expression of cell-cell interaction- and immune system-related pathways was reduced in these patients and in those with multiple brain metastases.

CONCLUSIONS

This is the first comprehensive proteomic analysis of paired primary tumors and brain metastases of LADC patients. Our data suggest a malfunction of cellular attachment and an increase in ribosomal activity in LADC tissue, promoting brain metastasis. The current study provides insights into the biology of LADC brain metastases and, moreover, might contribute to the development of personalized follow-up strategies in LADC.

Serum high-mobility group box 1 as a predictive marker for cytotoxic chemotherapy-induced lung injury in patients with lung cancer and interstitial lung disease

BACKGROUND

High-mobility group box 1 (HMGB1) is a pro-inflammatory protein, that is associated with tumorigenesis, interstitial lung disease (ILD), and acute lung injury. Chemotherapy-induced lung injury is a common and serious adverse event in patients with lung cancer and ILD, but its pathogenesis and predictive biomarkers are not known. This study aimed to investigate the predictive potential of serum HMGB1 levels for cytotoxic chemotherapy-induced lung injury in these patients.

METHODS

From 743 patients with advanced lung cancer, we enrolled 83 consecutive patients with ILD and background-matched 83 patients without ILD. Additionally, 83 healthy subjects were included. After measuring baseline levels of serum HMGB1 in three groups, we evaluated the predictive values of baseline HMGB1 levels for cytotoxic chemotherapy-induced lung injury in patients with lung cancer and ILD.

RESULTS

Higher levels of serum HMGB1 were independently associated with higher tumor burden, as assessed by total tumor size, and the presence of ILD. Twenty-five (30.1%) of patients with lung cancer and ILD experienced cytotoxic chemotherapy-induced lung injury within one year. Univariate Cox proportional hazards model showed that higher levels of HMGB1 and higher tumor burden were associated with disease onset. Moreover, multivariate analysis revealed that only HMGB1 was independently associated with this severe complication in patients with lung cancer and ILD.

CONCLUSIONS

HMGB1 is a potential predictive blood biomarker for cytotoxic chemotherapy-induced lung injury in patients with lung cancer and ILD. This study also suggests a potential pathogenesis of this serious adverse event that tumor- and ILD-derived HMGB1 accelerates lung injury.

High Mobility Group Box-1 (HMGB1): A Potential Target in Therapeutics

High mobility group box-1 (HMGB1) mainly belongs to the non-histone DNA-binding protein. It has been studied as a nuclear protein that is present in eukaryotic cells. From the HMG family, HMGB1 protein has been focused particularly for its pivotal role in several pathologies. HMGB-1 is considered as an essential facilitator in diseases such as sepsis, collagen disease, atherosclerosis, cancers, arthritis, acute lung injury, epilepsy, myocardial infarction, and local and systemic inflammation. Modulation of HMGB1 levels in the human body provides a way in the management of these diseases. Various strategies, such as HMGB1-receptor antagonists, inhibitors of its signalling pathway, antibodies, RNA inhibitors, vagus nerve stimulation etc. have been used to inhibit expression, release or activity of HMGB1. This review encompasses the role of HMGB1 in various pathologies and discusses its therapeutic potential in these pathologies.

Resveratrol and Diabetic Cardiomyopathy: Focusing on the Protective Signaling Mechanisms

Diabetic cardiomyopathy (DCM) is a common cardiovascular complication of diabetic mellitus that is characterized by diastolic disorder in the early stage and clinical heart failure in the later stage. Presently, DCM is considered one of the major causes of death in diabetic patients. Resveratrol (RSV), a naturally occurring stilbene, is widely reported as a cardioprotective substance in many heart diseases. Thus far, the specific roles of RSV in DCM prevention and treatment have attracted great attention. Here, we discuss the roles of RSV in DCM by focusing its downstream targets from both in vivo and in vitro studies. Among such targets, Sirtuins 1/3 and AMP-activated kinase have been identified as key mediators that induce cardioprotection during hyperglycemia. In addition, many other signaling molecules (e.g., forkhead box-O3a and extracellular regulated protein kinases) are also regulated in the presence of RSV and exert beneficial effects such as opposing oxidative stress, inflammation, and apoptosis in cardiomyocytes exposed to high-glucose conditions. The beneficial potential of an RSV/stem cell cotherapy is also reviewed as a promising therapeutic strategy for preventing the development of DCM.

Association of EGFR mutations and HMGB1 genetic polymorphisms in lung adenocarcinoma patients

High-mobility group protein box 1 (HMGB1) is overexpressed and reported to be a prognostic factor in patients with non-small-cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) mutants play an important role in NSCLC progression. The aim of this study was to explore potential associations between genetic polymorphisms of HMGB1 and EGFR mutations in a cohort that included 280 patients with NSCLC, some of whom were smokers and others who never smoked. Four tagged single-nucleotide polymorphisms (SNPs) of HMGB1 were detected by a TaqMan-based real-time polymerase chain reaction (PCR) in patients. We found that after adjusting for other covariates, NSCLC patients who smoked and who respectively had CG, CT, and TC heterozygotes of HMGB1 rs2249825, rs1045411, and rs1360485, were at lower risk of developing mutant EGFR, compared to those patients with wild-type homozygotes. Moreover, significant inverse associations between the CG and CG + GG genotypes of HMGB1 rs2249825 and the EGFR hotspot mutation, an exon 19 in-frame deletion, were also observed among NSCLC patients. Within patients harboring mutant EGFR, HMGB1 rs1360485 C (TC + CC) allele carriers were at higher risk of developing poorly differentiated cancer types (odds ratio=5.493, 95% confidence interval: 1.130~26.696, p=0.019), compared to patients with TT homozygotes. Furthermore, we found that HMGB1 rs1360485 polymorphisms seemed to be related to susceptibility to developing poorly differentiated cancer linked to tobacco consumption in EGFR mutant patients. In conclusion, our results suggested that HMGB1 variants are significantly inversely associated with EGFR mutations among NSCLC patients who smoked. HMGB1 variants and tobacco consumption might contribute to the pathological development of NSCLC.

Downregulation of high mobility group protein box-1 resensitizes ovarian cancer cells to carboplatin

Ovarian cancer, one of the most common types of cancer, has the highest mortality among all gynecological malignancies. The development of acquired drug resistance is the leading cause of chemotherapy failure. To study the mechanism underlying drug resistance in ovarian cancer, a drug-resistant ovarian cancer SKOV3 cell line was developed using the chemotherapeutic agent carboplatin (SKOV3-Carb) in the present study. It has been reported that high-mobility group protein box-1 (HMGB1) is associated with the chemoresistance of tumor cells. Therefore, the probable involvement of HMGB1 in the development of carboplatin resistance in ovarian cancer SKOV3 cells was investigated. HMGB1 has been reported to be overexpressed in carboplatin-resistant SKOV3-Carb cells compared with control SKOV3 cells. Subsequently, the expression of HMGB1 was silenced by small interference RNA technology. Reverse transcription-quantitative polymerase chain reaction and western blot analysis indicated that mRNA and protein expression levels of HMGB1 were significantly inhibited in HMGB1-silenced cells. Cell proliferation and apoptosis analyses were performed to evaluate the effect of HMGB1 silencing on resistant ovarian cancer cells. An MTT assay revealed that the proliferation of HMGB1-silenced SKOV3 and SKOV3-Carb cells were decreased compared with the proliferation of non-silenced control cells. Additionally, HMGB1 protein expression levels in SKOV3 cells, but not in SKOV3-Carb cells, were decreased in response to carboplatin treatment. Annexin V-fluorescein isothiocyanate/propidium iodide staining demonstrated that HMGB1 silencing enhanced the effects of carboplatin in inducing the apoptosis of SKOV3-Carb cells relative to HMGB1 non-silenced control cells. The results of the present study suggested that HMGB1 may be involved in the development of carboplatin resistance in ovarian cancer SKOV3 cells and that HMGB1 silencing may induce the sensitization of carboplatin-resistant ovarian cancer cells to carboplatin. Therefore, HMGB1 may be considered as a potent therapeutic target for increasing the sensitivity of ovarian cancer cells to carboplatin in order to improve the treatment and prognosis of ovarian cancer.

High Mobility Group Box Protein 1 Serves as a Potential Prognostic Marker of Lung Cancer and Promotes Its Invasion and Metastasis by Matrix Metalloproteinase-2 in a Nuclear Factor-κB-Dependent Manner

Several studies have reported a significant role of high mobility group box protein 1 (HMGB1) in lung cancer. Nevertheless, there is a lack of knowledge regarding the expression of HMGB1 and its correlation with the clinicopathological features of lung cancer. In addition, the potential molecular mechanisms underlying the role of HMGB1 in lung cancer are still unknown. We therefore investigated the clinicopathological and prognostic significance as well as the potential role of HMGB1 in the development and progression of lung cancer. HMGB1 expression in the tumor tissues of the cohort correlated with clinicopathological features. Moreover, lung cell migration and invasion were significantly increased after treatment with HMGB1. The matrix metalloproteinase-2 (MMP-2) expression and activity were upregulated after treatment with HMGB1, while the upregulated expression of MMP-2 stimulated by HMGB1 in lung cancer cells was significantly reduced with the blockage of si-p65. These results indicated that HMGB1 expression was significantly associated with lung cancer progression. We also showed that HMGB1 promoted lung cancer invasion and metastasis by upregulating the expression and activity of MMP-2 in an NF-κB-dependent manner. Taken together, these data suggested that HMGB1 may be a potential prognosis and therapeutic marker for lung cancer.

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

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

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

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

The effect of HMGB1 on the clinicopathological and prognostic features of non-small cell lung cancer

Several studies have assessed the diagnostic and prognostic values of high mobility group protein box 1 (HMGB1) expression in non-small cell lung cancer (NSCLC), but these results remain controversial. The purpose of this study was to perform a meta-analysis of the gene microarray analyses of datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) to evaluate the association of HMGB1 expression with the clinicopathological and prognostic features of patients with NSCLC. Furthermore, we investigated the underlying molecular mechanisms by bioinformatics analysis. Twenty relevant articles involving 2651 patients were included in this meta-analysis; the HMGB1 expression in NSCLC tissues was significantly higher than that in the healthy non-cancer control tissues. We also found an indication by microarray analysis and meta-analysis that HMGB1 expression was associated with the cancer TNM Staging System. In terms of prognostic features, a survival analysis from KM-Plotter tool revealed that the high HMGB1 expression group exhibited poorer survival in lung adenocarcinoma (ADC) and overall NSCLC patients. The survival and disease-free analyses from TCGA datasets also showed that HMGB1 mainly affected the development of patients with ADC. Therefore, we focused on how HMGB1 affected the prognosis and development of ADC using bioinformatics analyses and detected that the mitogen-activated protein kinases (MAPK), apoptosis and cell cycle signaling pathways were the key pathways that varied during HMGB1 up-regulation in ADC. Moreover, various genes such as PLCG2, the phosphatidylinositol-4, 5-bisphosphate 3-kinase superfamily (PI3Ks), protein kinase C (PKC) and DGKZ were selected as hub genes in the gene regulatory network. Our results indicated that HMGB1 is a potential biomarker to predict progression and survival of NSCLC, especially of ADC types.

High mobility group box 1/toll-like receptor 4/myeloid differentiation factor 88 signaling promotes progression of gastric cancer

High mobility group box 1 and toll-like receptor 4/myeloid differentiation factor 88 signaling pathway have been indicated to have oncogenic effects in many cancers. However, the role of high mobility group box 1/toll-like receptor 4/myeloid differentiation factor 88 signaling pathway in the development of gastric cancer remains unclear. In this study, we demonstrated that high mobility group box 1, toll-like receptor 4, and myeloid differentiation factor 88 were overexpressed in gastric cancer tumors compared with the adjacent non-tumor tissues. The overexpression of high mobility group box 1, toll-like receptor 4, and myeloid differentiation factor 88 were correlated with tumor-node-metastasis stage (p = 0.0068, p = 0.0063, p = 0.0173) and lymph node metastasis (p = 0.0272, p = 0.0382, and p = 0.0495). Furthermore, we observed that knockdown of high mobility group box 1 by high mobility group box 1-small interfering RNA suppressed the expression of toll-like receptor 4 and myeloid differentiation factor 88. Blockage of high mobility group box 1/toll-like receptor 4/myeloid differentiation factor 88 signaling by high mobility group box 1-small interfering RNA resulted in elevation of apoptotic ratio and inhibition of cell growth, migration, and invasion by upregulating Bax expression and downregulating Bcl-2, matrix metalloproteinase-2, nuclear factor kappa B/p65 expression, and the nuclear translocation of nuclear factor kappa B/p65 in gastric cancer cells. Our findings suggest that high mobility group box 1/toll-like receptor 4/myeloid differentiation factor 88 signaling pathway may contribute to the development and progression of gastric cancer via the nuclear factor kappa B pathway and it also represents a novel potential therapeutic target for gastric cancer.

MicroRNA-181b is downregulated in non-small cell lung cancer and inhibits cell motility by directly targeting HMGB1

The expression of microRNA-181b (miR-181b) has been investigated in various human cancers. However, the expression and functions of miR-181b in non-small cell lung cancer (NSCLC) are yet to be studied. In the present study, miR-181b expression in NSCLC tissues and cell lines was analyzed by quantitative polymerase chain reaction, and was shown to be recurrently downregulated. Following transfection of the H23 and H522 NSCLC cells lines with miR-181b, cell migration and cell invasion assays were performed to evaluate the effect of miR-181b overexpression on the cell motility. It was demonstrated that overexpression of miR-181b inhibited the migration and invasion of NSCLC cells. Subsequently, bioinformatics analysis, western blotting and luciferase reporter assays were conducted to investigate the mechanism underlying the miR-181b-mediated inhibition of NSCLC cell motility. It was found that miR-181b directly targeted high-mobility group box-1 (HMGB1) in NSCLC cells. These results reveal a novel therapeutic target, the miR-181b/HMGB1 axis, in NSCLC. Treatment approaches targeting this axis will be beneficial to prevent NSCLC from becoming invasive.

Association between an elevated level of HMGB1 and non-small-cell lung cancer: a meta-analysis and literature review

BACKGROUND

HMGB1 has been overexpressed in the tissues or serum of patients with non-small-cell lung cancer (NSCLC) in several studies. However, the results remain inconsistent.

OBJECTIVE

The aim of this study was to perform a meta-analysis to investigate the relationship between elevated level of HMGB1 and NSCLC.

METHODS

Associated studies were included, and the pooled risk difference and mean difference (MD) together with 95% confidence interval (CI) were calculated.

RESULTS

A total of ten relevant studies on HMGB1 expression were included in this meta-analysis. The pooled results suggested that the expression of HMGB1 in NSCLC tissues was notably higher than those in corresponding nontumor normal tissues by using immu-nohistochemistry (risk difference =0.38, 95% CI: 0.28-0.48, Z=7.67, P<0.00001, I (2)=0%), Western blot (MD =0.27, 95% CI: 0.06-0.47, Z=2.57, P<0.01), or real-time polymerase chain reaction (MD =15.15, 95% CI: 14.8-15.5, Z=2.08, P=0.04). Serum HMGB1 levels were similarly significantly higher in patients with NSCLC than those in healthy controls. The pooled MDs of HMGB1 in patients with NSCLC compared with healthy controls were 17.54 with 95% CI: 10.99-24.09, Z=5.25, P<0.00001. Two of the included studies were fully reviewed without performing meta-analysis due to the different detection methods used. The protein level of HMGB1 in patients with NSCLC of tumor, nodes, and metastasis (TNM) stages III-IV was higher than that of TNM stages I-II (P<0.047 and P<0.001, respectively).

CONCLUSION

The expression levels of HMGB1 in both tissues and serum of patients with NSCLC were statistically higher than those of normal lung samples, which indicated that elevated levels of HMGB1 can reveal changes that correlated with disease progression, or even the risk of NSCLC disease progression. The elevated level of HMGB1 could also be considered as a potential biomarker for the diagnosis of patients with NSCLC.

Effect of ulinastatin on the expression and distribution of high mobility group box 1 in human colon carcinoma cells in vitro

The aim of the present study was to investigate the in vitro effects of ulinastatin (UTI) on the proliferation, invasion, apoptosis, expression and distribution of high mobility group box 1 (HMGB1) and the expression of nuclear factor κB (NF‑κB) in human colon carcinoma LoVo cells. The cells were divided into control (untreated), UTI1 (400 U/ml UTI), UTI2 (800 U/ml UTI) and UTI3 (1,600 U/ml UTI) groups. The cell proliferation, invasion, apoptosis and the gene and protein expression of HMGB1 and NF‑κB were detected using a tetrazolium assay, Transwell cell invasion assays, a caspase‑3 activity assay, western blot analysis and reverse transcription quantitative polymerase chain reaction, respectively. The distribution of HMGB1 was detected using immunofluorescence. LoVo cell proilferation decreased the most in the UTI3 group followed, in order, by the UTI2, UTI1 and control groups. UTI inhibited invasion in LoVo cells and the inhibitory effect was enhanced as the UTI concentration increased. The activity of caspase‑3 increased the least in the control group followed, in order, by the UTI1, UTI2 and UTI3 groups. UTI inhibited the expression of HMGB1 and NF‑κB, and decreased the cytoplasmic distribution of HMGB1. Thus, UTI inhibited LoVo cell proliferation and induced LoVo cell apoptosis, the mechanism of which may be associated with a decreased in the expression of HMGB1 and NF‑κB, and the cytoplasmic distribution of HMGB1.

HMGB1 mediates hyperglycaemia-induced cardiomyocyte apoptosis via ERK/Ets-1 signalling pathway

Apoptosis is a key event involved in diabetic cardiomyopathy. The expression of high mobility group box 1 protein (HMGB1) is up-regulated in diabetic mice. However, the molecular mechanism of high glucose (HG)-induced cardiomyocyte apoptosis remains obscure. We aimed to determine the role of HMGB1 in HG-induced apoptosis of cardiomyocytes. Treating neonatal primary cardiomyocytes with HG increased cell apoptosis, which was accompanied by elevated levels of HMGB1. Inhibition of HMGB1 by short-hairpin RNA significantly decreased HG-induced cell apoptosis by reducing caspase-3 activation and ratio of Bcl2-associated X protein to B-cell lymphoma/leukemia-2 (bax/bcl-2). Furthermore, HG activated E26 transformation-specific sequence-1 (Ets-1), and HMGB1 inhibition attenuated HG-induced activation of Ets-1 via extracellular signal-regulated kinase 1/2 (ERK1/2) signalling. In addition, inhibition of Ets-1 significantly decreased HG-induced cardiomyocyte apoptosis. Similar results were observed in streptozotocin-treated diabetic mice. Inhibition of HMGB1 by short-hairpin RNA markedly decreased myocardial cell apoptosis and activation of ERK and Ets-1 in diabetic mice. In conclusion, inhibition of HMGB1 may protect against hyperglycaemia-induced cardiomyocyte apoptosis by down-regulating ERK-dependent activation of Ets-1.

Smoking exposure induces human lung endothelial cell adaptation to apoptotic stress

Prolonged exposure to cigarette smoking is the main risk factor for emphysema, a component of chronic obstructive pulmonary diseases (COPDs) characterized by destruction of alveolar walls. Moreover, smoking is associated with pulmonary artery remodeling and pulmonary hypertension, even in the absence of COPD, through as yet unexplained mechanisms. In murine models, elevations of intra- and paracellular ceramides in response to smoking have been implicated in the induction of lung endothelial cell apoptosis, but the role of ceramides in human cell counterparts is yet unknown. We modeled paracrine increases (outside-in) of palmitoyl ceramide (Cer16) in primary human lung microvascular cells. In naive cells, isolated from nonsmokers, Cer16 significantly reduced cellular proliferation and induced caspase-independent apoptosis via mitochondrial membrane depolarization, apoptosis-inducing factor translocation, and poly(ADP-ribose) polymerase cleavage. In these cells, caspase-3 was inhibited by ceramide-induced Akt phosphorylation, and by the induction of autophagic microtubule-associated protein-1 light-chain 3 lipidation. In contrast, cells isolated from smokers exhibited increased baseline proliferative features associated with lack of p16(INK4a) expression and Akt hyperphosphorylation. These cells were resistant to Cer16-induced apoptosis, despite presence of both endoplasmic reticulum stress response and mitochondrial membrane depolarization. In cells from smokers, the prominent up-regulation of Akt pathways inhibited ceramide-triggered apoptosis, and was associated with elevated sphingosine and high-mobility group box 1, skewing the cell's response toward autophagy and survival. In conclusion, the cell responses to ceramide are modulated by an intricate cross-talk between Akt signaling and sphingolipid metabolites, and profoundly modified by previous cigarette smoke exposure, which selects for an apoptosis-resistant phenotype.

Knockdown of HMGB1 inhibits growth and invasion of gastric cancer cells through the NF-κB pathway in vitro and in vivo

High mobility group box 1 (HMGB1) as a novel inflammatory molecule has been shown to be involved in a variety of cell physiological and pathological behaviors including immune response, inflammation and cancer. Evidence suggests that HMGB1 plays a critical role in the development and progression of multiple malignancies. However, the underlying molecular mechanisms for the HMGB1-mediated growth and invasion of gastric cancer have not yet been elucidated. The present study investigated the expression of HMGB1 in gastric adenocarcinoma (GAC) and the mechanisms by which it contributes to tumor growth and invasion. The correlation between HMGB1 expression and clinicopathological characteristics of GAC patients was assessed by immunohistochemical assay through tissue microarray procedures. The RNA and protein expressions of HMGB1 and downstream factors were detected by quantitative PCR and western blot assays; cell proliferation and invasion were determined by MTT, wound-healing and 3D-Matregel assays, subcutaneous SGC-7901 tumor models were established to verify tumor growth in vivo. We demonstrated that, the expression of HMGB1 was significantly increased in the nucleus of GAC tissues compared with that in adjacent non-cancer tissues (88.6 vs.70.5%, P<0.001), and correlated with the metastatic lymph node of GAC (P=0.018). Furthermore, knockdown of HMGB1 by shRNA inhibited cell proliferative activities and invasive potential, and downregulated the expression of NF-κB p65, PCNA and MMP-9 in GAC cells (SGC-7901 and AGS). The tumor volumes in SGC7901 subcutaneous nude mouse models treated with Lv-shHMGB1 was significantly smaller than those of the nonsense sequence group. Taken together, these findings suggest that increased expression of HMGB1 is associated with tumor metastasis of GAC, and knockdown of HMGB1 suppresses growth and invasion of GAC cells through the NF-κB pathway in vitro and in vivo, suggesting that HMGB1 may serve as a potential therapeutic target for GAC.

Lung adenocarcinoma complicated by Trousseau's syndrome successfully treated by a combination of anticoagulant therapy and chemotherapy

A 63-year-old woman was diagnosed with advanced lung adenocarcinoma complicated by Trousseau's syndrome characterized by non-bacterial thrombotic endocarditis, asymptomatic brain infarction, deep venous thrombosis, and low-grade disseminated intravascular coagulation (DIC). The patient's DIC rapidly became widespread, and multiple micropulmonary embolisms led to severe respiratory failure. She received a blood transfusion and anticoagulant treatment with heparin and recombinant human soluble thrombomodulin, which modestly ameliorated her symptoms, and additional chemotherapy led to tumor shrinkage with concomitant resolution of Trousseau's syndrome. Although there are no established medical approaches for managing Trousseau's syndrome, intensive anticoagulant treatment may be effective for improving the patients' general condition in order for them to be able to undergo subsequent combination chemotherapy.