BACKGROUND: Knee osteoarthritis (OA) is still challenging to prevent or treat. Enhanced endoplasmic reticulum (ER) stress and increased pyroptosis in chondrocytes may be responsible for cartilage degeneration. This study aims to investigate the effect of ER stress on chondrocyte pyroptosis and the upstream regulatory mechanisms, which have rarely been reported. METHODS: The expression of the histone methyltransferase enhancer of zeste homolog 2 (EZH2), microRNA-142-3p (miR-142-3p), and high mobility group box 1 (HMGB1) and the levels of ER stress, pyroptosis, and metabolic markers in normal and OA chondrocytes were investigated by western blotting, quantitative polymerase chain reaction, immunohistochemistry, fluorescence in situ hybridization, fluorescein amidite-tyrosine-valine-alanine-aspartic acid-fluoromethyl ketone (FAM-YVAD-FMK)/Hoechst 33342/propidium iodide (PI) staining, lactate dehydrogenase (LDH) release assays, and cell viability assessments. The effects of EZH2, miR-142-3p, and HMGB1 on ER stress and pyroptosis and the hierarchical regulatory relationship between them were analyzed by chromatin immunoprecipitation, luciferase reporters, gain/loss-of-function assays, and rescue assays in interleukin (IL)-1β-induced OA chondrocytes. The mechanistic contribution of EZH2, miR-142-3p, and HMGB1 to chondrocyte ER stress and pyroptosis and therapeutic prospects were validated radiologically, histologically, and immunohistochemically in surgically induced OA rats. RESULTS: Increased EZH2 and HMGB1, decreased miR-142-3p, enhanced ER stress, and activated pyroptosis in chondrocytes were associated with OA occurrence and progression. EZH2 and HMGB1 exacerbated and miR-142-3p alleviated ER stress and pyroptosis in OA chondrocytes. EZH2 transcriptionally silenced miR-142-3p via H3K27 trimethylation, and miR-142-3p posttranscriptionally silenced HMGB1 by targeting the 3'-UTR of the HMGB1 gene. Moreover, ER stress mediated the effects of EZH2, miR-142-3p, and HMGB1 on chondrocyte pyroptosis. In vivo experiments mechanistically validated the hierarchical regulatory relationship between EZH2, miR-142-3p, and HMGB1 and their effects on chondrocyte ER stress and pyroptosis. CONCLUSIONS A novel EZH2/miR-142-3p/HMGB1 axis mediates chondrocyte pyroptosis and cartilage degeneration by regulating ER stress in OA, contributing novel mechanistic insights into OA pathogenesis and providing potential targets for future therapeutic research.
Enhancer of Zeste Homolog 2 Protein/genetics* ; Osteoarthritis, Knee/pathology* ; Chondrocytes/metabolism* ; Pyroptosis/physiology* ; HMGB1 Protein/genetics* ; MicroRNAs/metabolism* ; Endoplasmic Reticulum Stress/genetics* ; Humans ; Animals ; Rats ; Male ; Rats, Sprague-Dawley ; Middle Aged

Objective This study investigated the regulatory effect of high mobility group protein B1 (HMGB1) in the peripheral blood of patients with primary immune thrombocytopenia (ITP) on myeloid dendritic cells (mDC) and Th17/regulatory T cells (Treg) balance. Methods The study enrolled 30 newly diagnosed ITP patients and 30 healthy controls.Flow cytometry was used to measure the proportion of mDC, Th17, and Treg cells in the peripheral blood of ITP patients and healthy controls. ELISA was conducted to quantify the serum levels of HMGB1, interleukin 6 (IL-6), IL-23, IL-17, and transforming growth factor β(TGF-β). The mRNA levels of retinoic acid-related orphan receptor γt(RORγt) and forehead box P3(FOXP3) were detected by real-time PCR. The correlation between the abovementioned cells, cytokines, and platelet count was assessed using Pearson linear correlation analysis. Results The proportion of Th17 cells and the expression levels of HMGB1, IL-6, IL-23, IL-17 and the level of RORγt mRNA in the peripheral blood of ITP patients were higher than those in healthy controls. However, the Treg cell proportion and TGF-β level were lower in ITP patients than those in healthy controls. In patients with ITP, the proportion of mDC and the level of FOXP3 mRNA did not show significant changes. The proportion of mDC cells was significantly correlated with the expression of IL-6 and IL-23. Moreover, the expression of HMGB1 showed a significant correlation with the expression of mDC, IL-6, IL-23, RORγt mRNA, and IL-17. Notably, both the proportion of mDC cells and the expression of HMGB1 were negatively correlated with platelet count. Conclusion The high expression of HMGB1 in peripheral blood of ITP patients may induce Th17/Treg imbalance by promoting the maturation of mDC and affecting the secretion of cytokines, thereby potentially playing a role in the immunological mechanism of ITP.
Humans ; Th17 Cells/cytology* ; HMGB1 Protein/genetics* ; T-Lymphocytes, Regulatory/cytology* ; Female ; Male ; Dendritic Cells/metabolism* ; Adult ; Middle Aged ; Purpura, Thrombocytopenic, Idiopathic/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; Young Adult ; Interleukin-23/blood* ; Interleukin-17/blood* ; Interleukin-6/blood* ; Forkhead Transcription Factors/genetics* ; Myeloid Cells/cytology* ; Aged

The aim of this study was to investigate the underlying mechanism of chrysophanol(Chr) in reducing inflammation and foam cell formation induced by oxidized low-density lipoprotein(ox-LDL) and to investigate the targets and pathways related to effects of Chr on coronary atherosclerosis, providing a theoretical basis for the development of new clinical drugs. RAW264.7 macrophages were cultured in vitro, and after determining the appropriate concentrations of Chr and ox-LDL for treating RAW264.7 macrophages using a cell counting kit-8(CCK-8), the macrophages were treated with different concentrations of Chr(10, 15 μmol·L~(-1)) and ox-LDL(with or without 80 mg·mL~(-1)) for 24 h. RAW264.7 macrophages were divided into four groups: control group, model group(80 mg·mL~(-1) ox-LDL), treatment group(80 mg·mL~(-1) ox-LDL+10 μmol·L~(-1) Chr), and treatment group(80 mg·mL~(-1) ox-LDL+15 μmol·L~(-1) Chr). Lipid accumulation in each group was detected by oil red O staining. CD36 expression was analyzed by flow cytometry. Western blot was used to detect the expression of scavenger receptor class A1(SR-A1), scavenger receptor class B type Ⅰ(SR-B1), autophagy-related protein 5(Atg5), Beclin-1, autophagy adaptor protein p62(P62), the ratio of microtubule-associated protein light chain 3(LC3)Ⅱ to LC3Ⅰ(LC3Ⅱ/LC3Ⅰ), nuclear factor kappa B P65(NF-κB P65), inhibitor of κB kinase β(IKKβ), nuclear factor of κB inhibitor(IκB), high mobility group box protein 1(HMGB1), phosphatidylinositol 3-kinase(PI3K), protein kinase B(Akt), and phosphorylated mammalian target of rapamycin(mTOR). Real-time quantitative polymerase chain reaction(RT-qPCR) was used to detect the mRNA expression levels of ATP-binding cassette transporter A1(ABCA1), ATP-binding cassette transporter G1(ABCG1), interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), HMGB1, inducible nitric oxide synthase(iNOS), arginase 1(Arg1), macrophage galactose-type lectin-1(Mgl-1), and NF-κB P65. Immunofluorescence analysis was performed to determine the localization of HMGB1 in RAW264.7 cells in each group. The autophagy inhibitor 3-methyladenine(3-MA) was added as a control for reverse validation, and the RAW264.7 macrophages were divided into four groups again: control group, model group(80 mg·mL~(-1) ox-LDL), treatment group(80 mg·mL~(-1) ox-LDL + 15 μmol·L~(-1) Chr), and inhibitor group(80 mg·mL~(-1) ox-LDL+15 μmol·L~(-1) Chr+3-MA). The results showed that Chr effectively reduced foam cell formation by regulating the expression levels of SR-A1, ABCA1, ABCG1, the LC3Ⅱ/LC3Ⅰ ratio, Atg5, Beclin-1, and p62, and inhibited the NF-κB/HMGB1-PI3K/Akt/mTOR signaling pathway. Moreover, the inhibitory effects of Chr on autophagy and the NF-κB/HMGB1-PI3K/Akt/mTOR pathway were reversed by the autophagy inhibitor 3-MA. In conclusion, Chr exhibits therapeutic potential for the treatment of atherosclerosis by inducing autophagy and modulating the NF-κB/HMGB1 and PI3K/Akt/mTOR pathways to inhibit the formation of macrophage inflammatory foam cells.
Animals ; Lipoproteins, LDL/metabolism* ; Mice ; TOR Serine-Threonine Kinases/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Macrophages/cytology* ; RAW 264.7 Cells ; Proto-Oncogene Proteins c-akt/genetics* ; Signal Transduction/drug effects* ; NF-kappa B/genetics* ; Anthraquinones/pharmacology* ; Foam Cells/cytology* ; HMGB1 Protein/genetics* ; Humans

OBJECTIVES: To explore the mechanism by which Wiskott-Aldrich syndrome protein family verprolin-homologous protein 1 (WAVE1) regulates lipopolysaccharide (LPS)-induced mitochondrial metabolic abnormalities and inflammatory responses in macrophages. METHODS: Macrophage cell lines with overexpressed WAVE1 (mouse BMDM and human THP1 cells) were prepared. The macrophages were treated with LPS (500 ng/mL) to simulate sepsis-induced inflammatory responses. The experiment consisted of two parts. The first part included control, LPS, vector (LPS+oe-NC), WAVE1 overexpression (LPS+oe-WAVE1) groups. The second part included LPS, LPS+oe-NC, LPS+oe-WAVE1 and exogenous high mobility group box-1 (HMGB1) intervention (LPS+oe-WAVE1+HMGB1) groups. RT-PCR was used to measure mitochondrial DNA content, and RT-qPCR was used to detect the mRNA expression levels of WAVE1, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. Western blot was performed to measure the protein expression of WAVE1, hexokinase 2, and pyruvate kinase M2. ELISA was utilized to detect the levels of TNF-α, IL-1β, IL-6, and HMGB1. JC-1 staining was used to assess mitochondrial membrane potential. Seahorse XP96 was used to evaluate oxygen consumption rate and extracellular acidification rate. MitoSOX probe was employed to measure mitochondrial reactive oxygen species levels, and 2-NBDG method was used to assess glucose uptake. Kits were used to measure pyruvate kinase activity, lactate, adenosine triphosphate (ATP), and HMGB1 levels. RESULTS: Compared with the control group, the LPS group showed lower levels of WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expression levels as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were significantly increased (P<0.05). Compared with the LPS+oe-NC group, the LPS+oe-WAVE1 group showed increased WAVE1 protein and mRNA expression, mitochondrial membrane potential, oxygen consumption rate, and mitochondrial DNA content (P<0.05), while TNF-α, IL-1β, IL-6 levels and mRNA expression, mitochondrial reactive oxygen species, glucose uptake, lactate, ATP, hexokinase 2, and pyruvate kinase M2 protein expressions, as well as extracellular acidification rate, pyruvate kinase activity, and HMGB1 release were decreased (P<0.05). Compared with the LPS+oe-WAVE1 group, the LPS+oe-WAVE1+HMGB1 group exhibited increased glucose uptake, lactate, ATP levels, and extracellular acidification rate (P<0.05). CONCLUSIONS WAVE1 participates in the regulation of LPS-induced inflammatory responses in macrophages by modulating the release of inflammatory factors, mitochondrial metabolism, and HMGB1 release.
Lipopolysaccharides ; Humans ; Mitochondria/metabolism* ; Animals ; Macrophages/metabolism* ; Mice ; Hexokinase/genetics* ; Wiskott-Aldrich Syndrome Protein Family/metabolism* ; HMGB1 Protein/physiology* ; Inflammation/metabolism* ; DNA, Mitochondrial ; Pyruvate Kinase/metabolism*

Objective: To explore the pathogenic mechanism of the miR-340/high mobility group box 1 (HMGB1) axis in the formation of liver fibrosis. Methods: A rat liver fibrosis model was established by injecting CCl(4) intraperitoneally. miRNAs targeting and validating HMGB1 were selected with gene microarrays after screening the differentially expressed miRNAs in rats with normal and hepatic fibrosis. The effect of miRNA expressional changes on HMGB1 levels was detected by qPCR. Dual luciferase gene reporter assays (LUC) was used to verify the targeting relationship between miR-340 and HMGB1. The proliferative activity of the hepatic stellate cell line HSC-T6 was detected by thiazolyl blue tetrazolium bromide (MTT) assay after co-transfection of miRNA mimics and HMGB1 overexpression vector, and the expression of extracellular matrix (ECM) proteins type I collagen and α-smooth muscle actin (SMA) was detected by western blot. Statistical analysis was performed by analysis of variance and the LSD-t test. Results: Hematoxylin-eosin and Masson staining results showed that the rat model of liver fibrosis was successfully established. Gene microarray analysis and bioinformatics prediction had detected eight miRNAs possibly targeting HMGB1, and animal model validation had detected miR-340. qPCR detection results showed that miR-340 had inhibited the expression of HMGB1, and a luciferase complementation assay suggested that miR-340 had targeted HMGB1. Functional experiments results showed that HMGB1 overexpression had enhanced cell proliferation activity and the expression of type I collagen and α-SMA, while miR-340 mimics had not only inhibited cell proliferation activity and the expression of HMGB1, type I collagen, and α-SMA, but also partially reversed the promoting effect of HMGB1 on cell proliferation and ECM synthesis. Conclusion: miR-340 targets HMGB1 to inhibit the proliferation and ECM deposition in hepatic stellate cells and plays a protective role during the process of liver fibrosis.
Animals ; Rats ; Cell Proliferation ; Collagen Type I/metabolism* ; Fibrosis ; Hepatic Stellate Cells ; HMGB1 Protein/genetics* ; Liver Cirrhosis/pathology* ; MicroRNAs/metabolism*

The study aimed to explore the mechanism and targets of Shenfu Injection in the regulation of inflammatory injury in chronic heart failure rats based on the high mobility group box-1/Toll like receptor 4/nuclear factor kappa-B(HMGB1/TLR4/NF-κB) signaling pathway. The rat model of chronic heart failure was established using isoproterenol. The modeled rats were divided into three groups by random number table: the model group, Shenfu group and glycopyrrolate group, and the normal group was also set. The rats were administrated for 15 consecutive days, and on the following day after the last administration, they were sacrificed for sample collection. The cardiac mass index and left ventricular mass index of the rats in each group were measured, and the echocardiogram was used to analyze the cardiac function indices, and ELISA to test the inflammatory indices in rat serum. The pathological morphology and fibrosis status of rat heart tissues were observed by HE staining and Masson staining, respectively. The content of HMGB1 was determined by immunofluorescence staining. The protein and mRNA expression of HMGB1/TLR4/TLR4 signaling pathway was detected by Western blot and RT-qPCR, respectively. The results showed that the chronic heart failure rat model was successfully prepared. The rats in the model group had reduced cardiac function, increased levels of HMGB1 and inflammatory factors(P<0.05), and elevated protein and mRNA expression of HMGB1, TLR4, MyD88, and NF-κB P65 in myocardial tissue(P<0.05), with fibrous connective tissue hyperplasia, inflammatory cell infiltration and severe fibrosis. Shenfu Injection improved cardiac function, decreased the levels of HMGB1 and inflammatory factors(P<0.05) and the protein and mRNA expression of HMGB1, TLR4, MyD88, and NF-κB P65 in myocardial tissue(P<0.05), ameliorated interstitial fibrous connective tissue hyperplasia and inflammatory cell infiltration, and reduced fibrosis. In conclusion, Shenfu Injection can reduce inflammatory damage and improve cardiac function in chronic heart failure rats by regulating the HMGB1/TLR4/NF-κB signaling pathway.
Rats ; Animals ; NF-kappa B/metabolism* ; HMGB1 Protein/pharmacology* ; Toll-Like Receptor 4/metabolism* ; Myeloid Differentiation Factor 88/metabolism* ; Hyperplasia ; Rats, Sprague-Dawley ; Signal Transduction ; RNA, Messenger ; Heart Failure/genetics* ; Fibrosis

OBJECTIVE: To investigate the role of long non-coding RNA ZEB1-AS1 in cerebral ischemia/reperfusion injury (CI/RI). METHODS: We detected the temporal changes of ZEB1-AS1 and HMGB1 expression using qPCR and Western blotting in SD rats following CI/RI induced by middle cerebral artery occlusion (MCAO). The rat models of CI/RI were subjected to injections of vectors for ZEB1-AS1 overexpression or knockdown into the lateral ventricle, and the changes in cognitive function, brain water content, blood-brain barrier integrity, and IL-1β and TNF-α levels in the cerebrospinal fluid (CSF) and serum were observed. Neuronal loss and cell apoptosis in the cortex of the rat models were detected by FJC and TUNEL methods, and HMGB1 and TLR-4 expressions were analyzed with Western blotting. We also examined the effects of ZEB1-AS1 knockdown on apoptosis and expressions of HMGB1 and TLR-4 in SH-SY5Y cells with oxygen-glucose deprivation/reoxygenation (OGD/R). RESULTS: In CI/RI rats, the expressions of ZEB1-AS1 and HMGB1 in the brain tissue increased progressively with the extension of reperfusion time, reaching the peak levels at 24 h followed by a gradual decline. ZEB1-AS1 overexpression significantly aggravated icognitive impairment and increased brain water content, albumin content in the CSF, and IL-1β and TNF-α levels in the CSF and serum in CI/RI rats (P < 0.05), while ZEB1-AS1 knockdown produced the opposite effects (P < 0.05 or 0.01). ZEB1-AS1 overexpression obviously increased the number of FJC-positive neurons in the cortex and enhanced the expressions of HMGB1 and TLR-4 in the rat models (P < 0.01); ZEB1-AS1 knockdown significantly reduced the number of FJC-positive neurons and lowered HMGB1 and TLR-4 expressions (P < 0.01). In SH-SY5Y cells with OGD/R, ZEB1-AS1 knockdown significantly suppressed cell apoptosis and lowered the expressions of HMGB1 and TLR-4 (P < 0.01). CONCLUSION ZEB1-AS1 overexpression aggravates CI/RI in rats through the HMGB1/TLR-4 signaling axis.
Animals ; Cell Line, Tumor ; Cell Proliferation/genetics* ; HMGB1 Protein/metabolism* ; Humans ; Infarction, Middle Cerebral Artery ; Neuroblastoma ; RNA, Long Noncoding/metabolism* ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; Toll-Like Receptor 4/metabolism* ; Tumor Necrosis Factor-alpha ; Water

To study the molecular mechanism for DNA hypomethylation of STAT3 promoter in CD4+ T cells from acute graft-versus-host disease (aGVHD) patients.
 Methods: We collected CD4+ T cells from peripheral blood of 42 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from HLA-identical sibling donors. GADD45A expression level in CD4+ T cells was measured by real-time PCR and Western blot. The binding level between HMGB1 and GADD45A in CD4+ T cells was analyzed by co-immunoprecipitation, while the binding levels of HMGB1/GADD45A with STAT3 promoter were detected by chromatin immunoprecipitation-quantitative real-time PCR (ChIP-qPCR). After overexpression of HMGB1 and knockdown of GADD45A in normal CD4+ T cells, STAT3 expression and DNA methylation were measured by Western blot and bisulfite sequencing PCR, respectively.
 Results: GADD45A expression was significantly up-regulated in patients with aGVHD compared with that in the patients without aGVHD. More HMGB1-GADD45A complexes were found in CD4+ T cells from patients with aGVHD compared with that in patients without aGVHD. The bindings of HMGB1/GADD45A with STAT3 promoter were significantly increased, and the binding levels of HMGB1/GADD45A were negatively correlated with STAT3 promoter DNA methylation. The expression of STAT3 was significantly reduced and the DNA methylation of STAT3 promoter was significantly increased in CD4+ T cells with overexpression of HMGB1 and knockdown of GADD45A compared with CD4+ T cells only with overexpression of HMGB1.
 Conclusion: The increased expression of HMGB1/GADD45A plays an importent role in STAT3 promoter DNA hypomethylation, thereby promoting STAT3 expression in CD4+ T cells from aGVHD patients.
CD4-Positive T-Lymphocytes ; Cell Cycle Proteins ; metabolism ; DNA Demethylation ; Gene Expression Regulation ; genetics ; Graft vs Host Disease ; genetics ; HMGB1 Protein ; metabolism ; Hematopoietic Stem Cell Transplantation ; Humans ; Nuclear Proteins ; metabolism ; Promoter Regions, Genetic ; genetics ; STAT3 Transcription Factor ; genetics ; metabolism

PURPOSE: High mobility group box 1 (HMGB1) plays a central role in the pathogenesis of sepsis and multiple organ dysfunction syndromes. We investigated the associations of a single nucleotide polymorphism (SNP; rs1045411) in HMGB1 with various clinical parameters, severity, and prognosis in patients with sepsis, severe sepsis, or septic shock. MATERIALS AND METHODS: We enrolled 212 adult patients followed for 28 days. All patients were genotyped for rs1045411, and the serum levels of HMGB1 and several cytokines were measured. RESULTS: The proportions of patients according to genotype were GG (71.2%), GA (26.4%), and AA (2.4%). Among patients with chronic lung disease comorbidity, patients with a variant A allele had higher positive blood culture rates and higher levels of various cytokines [interleukin (IL)-1beta, IL-6, IL-10, IL-17, and tumor necrosis factor-alpha] than those with the GG genotype. In the analysis of those with diabetes as a comorbidity, patients with a variant A allele had higher blood culture and Gram-negative culture rates than those with GG genotypes; these patients also had a higher levels of IL-17. In the analysis of those with sepsis caused by a respiratory tract infection, patients with a variant A allele had higher levels of IL-10 and IL-17 (all p<0.05). This polymorphism had no significant impact on patient survival. CONCLUSION: The variant A allele of rs1045411 appears to be associated with a more severe inflammatory response than the GG genotype under specific conditions.
Adult ; Aged ; Alleles ; Asian Continental Ancestry Group/genetics ; China/epidemiology ; Cytokines/*blood/*genetics ; Female ; Genotype ; HMGB1 Protein/blood/*genetics ; Humans ; Interleukin-10/genetics ; Interleukin-17/genetics ; Interleukin-6/blood ; Male ; Middle Aged ; Polymorphism, Genetic/*genetics ; Polymorphism, Single Nucleotide/*genetics ; Prognosis ; Republic of Korea ; Sepsis/immunology/*metabolism/mortality ; Shock, Septic/immunology/*metabolism/mortality ; Survival ; Tumor Necrosis Factor-alpha/genetics

OBJECTIVETo observe the effect of high-mobility group box-1 protein (HMGB1) on the proliferation of human nasopharyngeal carcinoma cell line C666-1 and explore the possible underlying mechanisms.

METHODSCultured C666-1 cells were treated with a siRNA targeting HMGB1 gene. The changes in the cell proliferation were detected by CCK8 analysis, the cell cycle distribution was assayed with flow cytometry, and the expressions of cyclin D1, CDK6 and related pathway proteins were detected with Western blotting. The effect of a HMGB1 plasmid carrying the reporter gene GFP on the proliferation of C666-1 cells was tested with CCK8 and EDU analysis.

RESULTSCompared with the control cells, the cells transfected with the siRNA targeting HMGB1 showed obviously suppressed cell proliferation (P<0.001), cell cycle arrest in G1 phase (P<0.001), and down-regulated expressions of cyclin D1, CDK6, STAT3 and P-STAT3. Overexpression of HMGB1 in cells transfected with the HMGB1 plasmid showed a significantly increased ratio of S phase cells (P<0.05) and obviously enhanced cell proliferation (P<0.001).

CONCLUSIONHMGB1 can promote the proliferation of human nasopharyngeal carcinoma cell line C666-1 by up- regulating cyclin D1 and CDK6 via the STAT3 signaling pathway.

Carcinoma ; Cell Cycle ; Cell Cycle Checkpoints ; Cell Division ; Cell Line, Tumor ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 6 ; metabolism ; Down-Regulation ; HMGB1 Protein ; genetics ; Humans ; Nasopharyngeal Neoplasms ; pathology ; RNA, Small Interfering ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Transfection ; Up-Regulation