Search

Cigarette smoke (CS) exposure is a risk factor for dyslipidemia and atherosclerosis. Reduced expression of low-density lipoprotein receptor (LDLR) in hepatocytes may be one of the underlying mechanisms for these disorders. The aim of the present study was to investigate the molecular mechanism underlying the regulatory effect of CS extract (CSE) on proprotein convertase subtilisin/kexin type 9 (PCSK9) and low LDLR expression in HepG2 cells. PCSK9 and LDLR mRNA and protein expression levels in HepG2 cells were evaluated after CSE treatment via reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. In addition, total intracellular reactive oxygen species (ROS) production was determined via 2,7-dichlorofluorescein diacetate fluorescence. CSE significantly increased PCSK9 expression and inhibited LDLR expression in a time- and concentration-dependent manner. Furthermore, CSE significantly induced ROS production and nuclear factor κB (NF-κB) activation. However, pretreatment with a ROS scavenger or an NF-κB inhibitor significantly attenuated the CSE-induced changes in PCSK9 and LDLR expression. In addition, pretreatment with melatonin markedly reduced ROS production, NF-κB activation and PCSK9 expression, and increased LDLR expression in the CSE-treated cells. These data suggest that melatonin inhibits CSE-regulated PCSK9 and LDLR production in HepG2 cells via ROS/NF-κB signaling.

Atherosclerosis is characterized by localized lesions distributed in the arterial tree due to the shear stress produced by blood flow. Endothelial cells are directly affected by alterations in blood flow. Dysfunction and injury to endothelial cells has been hypothesized to initiate the pathological processes of atherosclerosis. The present study aimed to investigate the mechanism of shear stress‑induced endothelial cellular apoptosis. Shear stress was generated using an artificial device to mimic the impact of disturbed blood flow on cultured human aortic endothelial cells (HAECs). Cellular apoptosis was assessed using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay; an ELISA assay was used to detect the produced interleukin (IL)‑1β; specific small interfering (si)RNA was used to knockdown the expression of interleukin‑1 receptor‑associated kinase 2 (IRAK2) in HAECs and the expression levels of 78 kDa glucose‑regulated protein, DNA damage‑inducible transcript 3 protein (CHOP), IRAK2 and IL‑1β were evaluated using western blotting. The results of the present study demonstrated that artificial shear stress induced endoplasmic reticulum (ER) stress, IL‑1β production and apoptosis in HAECs in a time‑dependent manner. The inhibition of ER stress, and treatment with interleukin‑1 receptor antagonist protein and siRNA against IRAK2 attenuated shear stress‑induced CHOP signaling‑mediated cellular apoptosis. Therefore, overproduction of IL‑1β exacerbated shear stress‑induced ER stress‑mediated apoptosis via the IRAK2/CHOP signaling pathway in endothelial cells.

Reactive microglia are present in lesions of myelin-associated white matter disorders resulting in injuries to oligodendrocyte precursor cells (OPCs). Therefore, protection of OPCs from injury due to excessive activation of microglia is important in treating these diseases. Heat shock protein 60 (HSP60) has been demonstrated to be released extracellularly in the failing heart upon stress or injury. However, the role of HSP60 in the central nervous system and whether it participates in the toxic effects of microglia on OPCs remains unclear. The present study used the co-culture, cell death assays, binding assays, immunochemistry, western blot and ELISA. HSP60 was demonstrated to be released extracellularly by LPS-activated microglia and to bind to OPCs, triggering OPC apoptosis. When pretreated with toll-like receptor (TLR) 4 blocking antibody, the viability of OPCs increased, while the expression of nuclear factor κB (NFκB), caspase 3 and the release of proinflammatory cytokines triggered by HSP60 decreased. These results suggest that HSP60 released by microglia may mediate OPC apoptosis through binding to TLR4 on the surface of OPCs and subsequently activating the TLR4-NFκB signaling pathway. HSP60 may, therefore, serve as a potential target for treatment of myelin-associated neurodegenerative diseases that are accompanied by microglia activation.

Oxidized low-density lipoprotein (oxLDL) can bind to β2-glycoprotein I (β2GPI) and C-reactive protein (CRP) to form stable complexes, which exert certain effects in diabetic cardiovascular disease. A previous study by our group has confirmed that the resulting complexes promote atherosclerosis in diabetic BALB/c mice. The present study was designed to investigate the effects and potential mechanisms of oxLDL complexes on lipid accumulation and inflammatory reactions in RAW264.7 macrophages cultured in a hyperglycemic environment. Cultured cells were divided into seven groups, which were treated with phosphate‑buffered saline (control), CRP, β2GPI, oxLDL, CRP/oxLDL, oxLDL/β2GPI or CRP/oxLDL/β2GPI. The results revealed the formation of foam cells in the oxLDL, CRP/oxLDL, oxLDL/β2GPI as well as CRP/oxLDL/β2GPI groups. Compared with oxLDL, the three complexes induced less lipid accumulation (P0.05) through inhibiting the expression of CD36 mRNA and promoting the expression of and ABCG1 mRNA (P0.05 vs. oxLDL). Furthermore, the levels of inflammatory factors interleukin (IL)‑1β, IL‑6 and tumor necrosis factor‑α were elevated in the CRP/oxLDL and CRP/oxLDL/β2GPI groups (P0.05 vs. oxLDL), and obvious effects on p38/mitogen‑activated protein kinase and nuclear factor (NF)‑κB phosphorylation were also observed in these groups (P0.05 vs. oxLDL). These results suggested that CRP/oxLDL/βG2P1 complexes may induce lipid accumulation and inflammation in macrophages via the p38/MAPK and NF‑κB signaling pathways. However, some differences were observed between the complexes, which may be attributed to the property of each constituent; therefore, further studies are required.

Colon cancer is one of the most common malignant tumors worldwide. Understanding the underlying molecular mechanisms is crucial for the development of therapeutic strategies for the treatment of patients with colon cancer. In the present study, a novel tumor suppressive microRNA, miR‑192, was demonstrated to be markedly downregulated in colon cancer cells compared with normal colon cells. By overexpressing miR‑192 in colon cancer HCT‑116 cells, the results of the present study revealed that miR‑192 inhibits cell proliferation, migration and invasion. Bioinformatics were used to determine the target gene of miR‑192 and Ras‑related protein Rab‑2A (RAB2A) was identified as a downstream target of miR‑192. Following the determination of the role of the miR‑192‑RAB2A pathway in colon cancer, small molecules that may regulate miR‑192 were screened and the results demonstrated that simvastatin is an activator of miR‑192. Furthermore, simvastatin upregulated miR‑192 and inhibited the expression of downstream targets of miR‑192, which subsequently led to suppressed proliferation, migration and invasion of colon cancer cells. In conclusion, the present study identified a novel colon cancer cell suppressor, as well as a small‑molecule activator of the tumor suppressor miR‑192, which may represent a therapeutic strategy for the treatment of patients with colon cancer.

Oxymatrine (OMT), which is a quinolizidine alkaloid extracted from the traditional Chinese herb Sophora flavescens Aiton, is often used to treat various inflammatory diseases. The present study aimed to investigate the protective effects of OMT against septic shock‑induced myocardial injury in rats, and to determine the underlying mechanisms. In the present study, cecal ligation and puncture (CLP) was applied to generate a rat model of sepsis. The rats were randomly divided into six groups (n=8/group): Sham operation (CON) group, OMT control group, CLP model group, and CLP + OMT (high dose, 52 mg/kg; medium dose, 26 mg/kg; low dose, 13 mg/kg) groups. Cardiac function and histological alterations were analyzed by light microscopy and electron microscopy. Myocardial cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The mRNA and protein expression levels were examined by reverse transcription-polymerase chain reaction and western blotting, respectively. Furthermore, the levels of tumor necrosis factor (TNF)‑α in the myocardial tissue were determined by radioimmunoassay. The results demonstrated that OMT exhibited anti‑inflammatory properties, improved myocardial contractility and compliance, and significantly decreased pathological injury to rat myocardial ultrastructure. In addition, OMT significantly decreased heart rate and left ventricular end diastolic pressure, and increased mean arterial pressure, left intraventricular pressure change rate, and left ventricular end systolic pressure in rats following septic shock. Treatment with OMT attenuated the mRNA expression of lipopolysaccharide binding protein, cluster of differentiation 14, nuclear factor (NF)‑κB (p65), TNF‑α, p38‑mitogen‑activated protein kinase (MAPK) and caspase‑3, and decreased the protein expression of NF‑κB (p65), phosphorylated (p) NF‑κB inhibitor‑α, p‑p38‑MAPK caspase‑3 and TNF‑α in septic myocardial tissue. The present study concluded that OMT may offer substantial therapeutic potential for the treatment of septic shock‑induced myocardial injury by inhibiting the TNF-α/p38-MAPK/caspase-3 signaling pathway.

Epigenetic gene silencing due to promoter methylation is observed in human neoplasia, including lymphoma and certain cancer types. One important target for gene methylation analysis in non-Hodgkin lymphoma (NHL) is inhibitor of DNA binding 4 (ID4). The present study aimed to investigate the gene methylation status of ID4, the expression of ID4 protein and the effect of demethylating agent 5-aza-2'-deoxycytosine (CdR) in the Raji human Burkitt's lymphoma cell line in vitro. Following assessment of the inhibition of Raji cell growth by various concentrations of CdR, the effects of CdR on the expression of ID4 protein were assessed using the immunocytochemical streptavidin-peroxidase method and semi-quantitative analysis, while apoptosis and cell cycle were determined by flow cytometry. The ID4 gene methylation status of Raji cells was tested using methylation-specific polymerase chain reaction analysis. ID4 was methylated and its protein expression was low in the control group, while ID4 was partly or completely demethylated and its protein expression was upregulated in Raji cells treated with CdR. In addition, CdR induced apoptosis and cell cycle arrest in Raji cells in a dose- and time-dependent manner. These results demonstrated that ID4 is hypermethylated and its protein expression is low in Burkitt's lymphoma cells, while CdR reversed the abnormal DNA methylation and induced re-expression of ID4 protein. Hypermethylation of ID4 promotes the proliferation of Burkitt's lymphoma cells; ID4 may function as a tumor suppressor and can be targeted with demethylating compounds such as CdR for the treatment of Burkitt's lymphoma.

Cardiac remodeling is a major determinant of heart failure characterized by cardiac hypertrophy and fibrosis. Sanguinarine exerts widespread pharmacological effects, including antitumor and anti‑inflammatory responses. In the present study, the effect of sanguinarine on cardiac hypertrophy, fibrosis and heart function was determined using the model induced by aortic banding (AB) in mice. AB surgery and sham surgery were performed on male wild‑type C57 mice, aged 8‑10 weeks, with or without administration of sanguinarine from one week after surgery for an additional seven weeks. Sanguinarine protected against the cardiac hypertrophy, fibrosis and dysfunction induced by AB, as assessed by the heart weight/body weight, lung weight/body weight and heart weight/tibia length ratios, echocardiographic and hemodynamic parameters, histological analysis, and the gene expression levels of hypertrophic and fibrotic markers. The inhibitory effect of sanguinarine on cardiac remodeling was mediated by inhibiting nuclear factor (NF)‑κB signaling pathway activation. The findings indicated that sanguinarine protected against cardiac hypertrophy and fibrosis via inhibiting NF‑κB activation. These findings may be used to develop a potential therapeutic drug for treating cardiac remodeling and heart failure.

At present, it is elusive how non-small cell lung cancer (NSCLC) develops resistance to γ-radiation; however, the transcription factor nuclear factor-κB (NF-κB) and NF-κB-regulated gene products have been proposed as mediators. Ginsenoside Rg3 is a steroidal saponin, which was isolated from Panax ginseng. Ginsenoside Rg3 possesses high pharmacological activity and has previously been shown to suppress NF-κB activation in various types of tumor cell. Therefore, the present study aimed to determine whether Rg3 could suppress NF-κB activation in NSCLC cells and sensitize NSCLC to γ-radiation, using an NSCLC cell line and NSCLC xenograft. A clone formation assay and lung tumor xenograft experiment were used to assess the radiosensitizing effects of ginsenoside Rg3. NF-κB/inhibitor of NF-κB (IκB) modulation was ascertained using an electrophoretic mobility shift assay and western blot analysis. NF-κB-regulated gene products were monitored by western blot analysis. The present study demonstrated that ginsenoside Rg3 was able to sensitize A549 and H1299 lung carcinoma cells to γ-radiation and significantly enhance the efficacy of radiation therapy in C57BL/6 mice bearing a Lewis lung carcinoma cell xenograft tumor. Furthermore, ginsenoside Rg3 suppressed NF-κB activation, phosphorylation of IκB protein and expression of NF-κB-regulated gene products (cyclin D1, c-myc, B-cell lymphoma 2, cyclooxygenase-2, matrix metalloproteinase-9 and vascular endothelial growth factor), a number of which were induced by radiation therapy and mediate radioresistance. In conclusion, the results of the present study suggested that ginsenoside Rg3 may potentiate the antitumor effects of radiation therapy in NSCLC by suppressing NF-κB activity and NF-κB-regulated gene products, leading to the inhibition of tumor progression.