BACKGROUNDNuclear factor kappaB (NF-kappaB) overactivation, requiring phosphorylation and degradation of its inhibitor IkappaBalpha, is the basis for chronicity of airway inflammation in asthma. Based on our previous plasmid pShuttle-IkappaBalpha, carrying an IkappaBalpha gene from human placenta, we optimized a novel IkappaBalpha mutant (IkappaBalphaM) gene, constructed and characterized its replication-deficient recombinant adenovirus (AdIkappaBalphaM), and tested whether AdIkappaBalphaM-mediated overexpression of IkappaBalphaM could inhibit the NF-kappaB activation in endothelial cells.

METHODSIkappaBalphaM gene (203 - 1003 bp) encoding 267 amino acids, acquired by site-directed deleting N-terminal phosphorylation sites of serine 32/36, was subcloned into the pShuttle and pGEM-T vectors for further polymerase chain reaction (PCR), restriction digestion, deoxyribonucleic acid (DNA) sequencing and homology analyses. Subsequent to inserting the expression unit of pShuttle-IkappaBalphaM, containing cytomegalovirus (CMV) promoter, IkappaBalphaM complementary DNA (cDNA) and polyadenylic acid (PolyA) signals, into the type 5 adenovirus (Ad5) vector, the resultant AdIkappaBalphaM was packaged in human embryonic kidney (HEK) 293 cells by cotransfection with lipofectamine. Western blot analysis and electrophoretic mobility shift assay were utilized to detect the AdIkappaBalphaM-mediated overexpression of IkappaBalphaM in HEK293 cells and its suppressive effect on phorbol 12-myristate 13-acetate (PMA)-induced NF-kappaB activation in human umbilical vein endothelial (ECV304) cells, respectively.

RESULTSThe relevant nucleotides and deduced amino acids of 801 bp IkappaBalphaM gene were consistent with those of IkappaBalpha gene (GenBank accession number: M69043). The titer of the prepared AdIkappaBalphaM was 4.0 x 10 (12) plaque-forming units (pfu)/L. Moreover, the IkappaBalphaM gene was overexpressed in HEK293 cells, and potently inhibited the PMA-induced NF-kappaB activation in ECV304 cells dose-dependently.

CONCLUSIONSAdIkappaBalphaM is a novel vector for both efficient transfer and specific overexpression of IkappaBalphaM gene, as well as potent inhibition of NF-kappaB activity, providing a promising strategy for gene therapy of asthma.

Adenoviridae ; genetics ; Cell Line ; Endothelial Cells ; metabolism ; Genetic Therapy ; Humans ; I-kappa B Proteins ; genetics ; Mutation ; NF-KappaB Inhibitor alpha ; NF-kappa B ; antagonists & inhibitors ; Tetradecanoylphorbol Acetate ; pharmacology

OBJECTIVETo investigate the cytotoxicity of bromoxynil on SH-SY5Y cells and its effect on the expression of nuclear factor-kappa B (NF-κB) and I kappa B alpha (IκBα) in SH-SY5Y cells.

METHODSSH-SY5Y cells were exposed to bromoxynil (10, 50, or 100 µmol/L) for 24 and 48 h, and other SH-SY5Y cells, which were used as a control, were exposed only to dimethyl sulfoxide. After 24 and 48 h of exposure, the morphological changes of these cells were observed under an inverted microscope, and the cytotoxicity of bromoxynil was measured by MTT assay. The cellular proliferation was examined by cell counting after 12, 24, 48, 72, and 96 h of exposure. After 24 h of exposure, the expression of NF-κB was evaluated by Western blot and immunocytochemistry, and the expression of IκBα was evaluated by Western blot.

RESULTSThe cellular proliferation inhibition rates (CPIRs) of 50 and 100 µmol/L groups were significantly higher than that of the control group after 24 and 48 h of exposure (P < 0.05); the CPIR was significantly higher after 48 h than after 24 h in the two groups (P < 0.05). The growth curve revealed that these groups began to show differences in cell count at the 24th of exposure and that the differences were even more marked as the exposure went on (F = 17.15, P < 0.05). The control group had a significantly increased cell count at the 48th, 72nd, and 96th h of exposure (P < 0.05); the 10 and 50 µmol/L groups had a significantly increased cell count at the 72nd and 96th h of exposure (P < 0.05); the 100 µmol/L group showed no significant change in cell count during 96h of exposure. The 50 and 100 µmol/L groups hada significantly longer cell doubling time than the control group (P < 0.05). The immunocytochemistry showed that as the dose of bromoxynil increased, the brownish yellow particles in the cytoplasm and nuclei became darker, the expression of NF-κB was upregulated, and the nuclear translocation of NF-κB was increased. The Western blot showed that the 100 µmol/L group had significantly higher expression of NF-κB in the nuclei than the control group (P < 0.05) and that the 50 and 100 µmol/L groups had significantly lower expression of IκB&alpha; in total proteins than the control group (P < 0.05).

CONCLUSIONBromoxynil can inhibit the proliferation of SH-SY5Y cells under this experimental condition, which may be related to activation of NF-κB.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Humans ; I-kappa B Proteins ; metabolism ; NF-KappaB Inhibitor alpha ; NF-kappa B ; metabolism ; Nitriles ; toxicity

Constitutive activation of nuclear transcription factor-κB (NF-κB) exists in a variety of leukemia, and induction of apoptosis through blocking NF-κB activation may be an alternative strategy for leukemia treatment. The aim of this study was to investigate the inducing effect of modified adenovirus 5-based adenovirus vector (i.e. chimeric Ad5F35 Vec)-mediated expression of mutant IκB&alpha; (IκB&alpha;DN) on apoptosis of HL-60 cells. The recombinant Ad5F35-IκB&alpha;DN Vec carrying IκB&alpha;DN cDNA which deleted the first 1-70 amino acids coding sequences at 5' terminal of human IκB&alpha; was transfected into HL-60 cells. The apoptosis, NF-κB DNA binding activity, the expressions of IκB&alpha;, cIAP-2 and xIAP in HL-60 cells were detected by DNA binding assay, flow cytometry, real-time quantitative polymerase chain reaction and Western blot respectively. The results showed that apoptosis rates were 22.53 ± 2.999%, 6.08 ± 2.464% and 4.86 ± 1.366% for Ad5F35-IκB&alpha;DN Vec-infected or blank vector of Ad5F35-EGFP Vec-transfected and untransfected HL-60 cells respectively, which showed a significant difference between Ad5F35-IκB&alpha;DN Vec-transfected and untransfected cells (p < 0.001) and between Ad5F35-IκB&alpha;DN Vec-transfected and Ad5F35-EGFP Vec-transfected cells (p < 0.001, p < 0.002), while NF-κB DNA binding activity was decreased, the truncated IκB&alpha; was expressed, and IκB&alpha; mRNA expression was up-regulated, but the expression of cIAP-2 and xIAP mRNA was down-regulated after transduction for 48 hours. It is concluded that the chimeric Ad5F35 Vec can effectively mediate the expression of IκB&alpha;DN cDNA in HL-60 cells, leading to the inhibition of NF-κB DNA binding activity and inducing apoptosis of HL-60 cells.
Adenoviridae ; genetics ; Apoptosis ; Genetic Vectors ; HL-60 Cells ; Humans ; I-kappa B Proteins ; genetics ; NF-KappaB Inhibitor alpha ; NF-kappa B ; genetics ; Transfection

This study was aimed to investigate the effect of hypoxia on lipopolysaccharide (LPS)-induced CXC-chemokine ligand-10 (CXCL10) expression and the underlying mechanism. C57BL/6J mice were randomly divided into control, hypoxia, LPS, and hypoxia combined with LPS groups. The LPS group was intraperitoneally injected with 0.5 mg/kg LPS, and the hypoxia group was placed in a hypobaric hypoxia chamber (simulated altitude of 6 000 m). The serum and hippocampal tissue samples were collected after 6 h of the treatment. The levels of CXCL10 in the serum and hippocampal tissue of mice were detected by ELISA. The microglia cell line BV2 and primary microglia were stimulated with hypoxia (1% O₂) and/or LPS (100 ng/mL) for 6 h. The mRNA expression level of CXCL10 and its content in culture supernatant were detected by real-time quantitative PCR and ELISA, respectively. The phosphorylation levels of nuclear factor κB (NF-κB) signaling pathway-related proteins, p65 and IκBα, were detected by Western blot. Moreover, after NF-κB signaling pathway being blocked with a small molecular compound, PDTC, CXCL10 mRNA expression level was detected in the BV2 cells. The results showed that in the LPS-induced mouse inflammatory model, hypoxia treatment could promote LPS-induced up-regulation of CXCL10 in both serum and hippocampus. Compared with the cells treated with LPS alone, the expression of CXCL10 mRNA and the content of CXCL10 in the culture supernatant of BV2 cells treated with hypoxia combined with LPS were significantly increased. The CXCL10 mRNA level of primary microglial cells treated with hypoxia combined with LPS was significantly up-regulated. Compared with the cells treated with hypoxia or LPS alone, the phosphorylation levels of p65 and IκBα in the BV2 cells treated with hypoxia combined with LPS were significantly increased. PDTC blocked the induction of CXCL10 gene expression by LPS in the BV2 cells. These results suggest that hypoxia promotes LPS-induced expression of CXCL10 in both animal and cell models, and NF-κB signaling pathway plays an important role in this process.
Animals ; Mice ; Chemokines, CXC/pharmacology* ; Hypoxia ; Ligands ; Lipopolysaccharides/pharmacology* ; Mice, Inbred C57BL ; Microglia/metabolism* ; NF-kappa B/metabolism* ; NF-KappaB Inhibitor alpha/pharmacology* ; RNA, Messenger/metabolism*

OBJECTIVETo investigate, from cytoprotein and molecular levels, the action mechanism of astragalus injection (ASI) on the signal conduction of human renal tubular cells (HK-2) injury induced by neonatal postasphyxial-serum (NPS), whether it is through activating the nuclear factor kappaB (NF-kappaB) signaling pathway.

METHODSTaking HK-2 as the target cell and the 20% NPS as the attacking factor, the experiment was conducted by dividing the target cells into two groups before attacking, the blank control group and the ASI pretreated group. The nuclear translocation of NF-kappaB was detected by confocal microscopy with indirect immunofluorescence stain, and the amount of NF-kappaB inhibitor subunit (I-kappaBalpha) was detected by Western blot before attacking. The detections were repeated at various time points in the experiment, i.e., 15 min, 1 h and 2 h after attacking, respectively.

RESULTSBefore attacking, the nuclear translocation of NF-kappaB and the amount of I-kappaBalpha were not different in the two groups. But the former increased and the latter decreased significantly in the ASI group at all the time points after attacking with the topmost changes presented at 1 h after attacking, and significantly different to those in the control group at corresponding time

CONCLUSIONASI pretreatment could inhibit the activation of NF-kappaB induced by postasphyxial-serum.

Apoptosis ; Asphyxia Neonatorum ; blood ; Astragalus Plant ; Cell Line ; Humans ; I-kappa B Proteins ; metabolism ; Infant, Newborn ; Kidney Tubules ; cytology ; metabolism ; NF-KappaB Inhibitor alpha ; Signal Transduction

This study aims to investigate the function of two SNPs (rs8904C > T and rs696G >A) in 3' untranslated region (3'UTR) of NFKBIA gene by constructing luciferase reporter gene. A patient's genomic DNA with rs8904 CC and rs696 GA genotype was used as the PCR template. Full-length 3'UTR of NFKBIA gene was amplified by different primers. After sequencing validation, these fragments were inserted to the luciferase reporter vector, pGL3-promoter to construct recombinant plasmids containing four kinds of haplotypes, pGL3-rs8904C/rs696G, pGL3-rs8904C/rs696A, pGL3-rs8904T/rs696G and pGL3-rs8904T/rs696A. Then these plasmids were transfected into LS174T cells and the luciferase activity was detected. Compared with pGL3-vector transfected cells (negative control), the luciferase activity of the four kinds of recombinant plasmids was significantly decreased (P < 0.001). For rs696G > A, the luciferase activity of the recombinant plasmids containing A allele (pGL3-rs8904C/rs696A and pGL3-rs8904T/rs696A) was about 45.1% (P < 0.05) and 56.1% (P < 0.001) lower than those containing G allele (pGL3-rs8904C/rs696G and pGL3-rs8904T/rs696G), respectively. For rs8904C > T, there were no significant differences in the luciferase activity between the recombinant plasmids containing T allele and those with C allele. Together, the luciferase reporter gene vectors containing SNPs in NFKBIA gene 3'UTR were constructed successfully and rs696G > A could decrease the luciferase activity while rs8904C >T didn't have much effect on the luciferase activity.
3' Untranslated Regions ; Genes, Reporter ; Genetic Vectors ; Humans ; I-kappa B Proteins ; genetics ; Luciferases ; NF-KappaB Inhibitor alpha ; Plasmids ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic ; Transfection

OBJECTIVETo study the expression and significance of p65 which is an important subtype of nuclear transcription factor kappaB (NF-kappaB) and its inhibitory protein IkappaBalpha in malignant transformation of hamster buccal mucosa.

METHODSThe animal model of malignant transformation in hamster buccal mucosa induced by DMBA (0.5%) was established. Twelve paired specimens including normal buccal mucosa, epithelial hyperplasia, epithelial dysplasia and squamous cell carcinoma (SCC) were subjected to Western blot for the analysis of p65. The expression of IkappaBalpha was observed in 22 normal buccal epithelia, 20 hyperplasia epithelia, 35 dysplasia epithelia and 23 SCC by immunohistochemical evaluation.

RESULTSIn normal buccal epithelia and hyperplasia epithelia, the expression of p65 was not obvious, and there was no significant difference between them (P > 0.05). The expression of IkappaBalpha existed at large, but mostly localizing in cell cytoplasmic staining in the basal cell layer and bottom of spinocelluar layer. With the occurrence of epithelia dysplasia, the expression of p65 gradually increased, comparing with normal buccal epithelia and hyperplasia epithelia (P < 0.01). But the positive intensity of IkappaBalpha was dramatically decreased (P < 0.05). In SCC, p65 expressed at a higher level comparing with normal buccal mucosa and dysplasia (P < 0.01), while the staining of IkappaBalpha was feedbackly higher comparing with dysplasia (P < 0.01) and even with normal buccal mucosa (P < 0.01).

CONCLUSIONNF-kappaB p65 is strongly activated in malignant transformation of hamster buccal mucosa. The abnormal expression of p65 and IkappaBalpha, especially the ascending expression of p65 as well as the descending expression of IkappaBalpha in dysplasia may be an early event during oral carcinogenesis, and can be used as biomarkers for supervising oral malignancy.

Animals ; Carcinogenesis ; Carcinoma, Squamous Cell ; Cheek ; Cricetinae ; Epithelium ; I-kappa B Proteins ; Mouth Mucosa ; Mouth Neoplasms ; NF-KappaB Inhibitor alpha ; Transcription Factors

OBJECTIVE: To examine the expression of the inhibitor alpha of nuclear transcription factor kappaB (IkappaBalpha) mRNA expression and its sequence characteristics in human nasopharyngeal carcinoma cell (NPC) lines CNE1, CNE2, HNE1 and HNE2. METHODS: Reverse transcription was performed with the total RNAs isolated from the NPC cell lines CNE1, CNE2, HNE1 and HNE2, as well as the transplanted tumor tissues with HNE1 cells. Then IkappaBalpha cDNA was amplified by PCR, and the products were used to examine IkappaB alpha mRNA expression and DNA sequencing, or the DNA sequencing after the products were cloned into plasmid vector. RESULTS: IkappaB alpha mRNA was expressed in all the 4 nasopharyngeal carcinoma cell lines. DNA sequencing showed that polymorphisms and 5 mutations (A825G, A975G, G576A, A655G and C653A) existed in IkappaB cDNA from the transplanted tumor tissues with HNE1 cells, CNE1 and CNE2 cells. CONCLUSION The expression of IkappaBalpha mRNA not only exists, but DNA polymorphisms and some additional mutations in IkappaBalpha cDNA are also detected in the nasopharyngeal carcinoma cells.
Base Sequence ; Carcinoma ; Cell Line, Tumor ; Humans ; I-kappa B Proteins ; genetics ; NF-KappaB Inhibitor alpha ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; genetics ; Polymorphism, Genetic ; RNA, Messenger ; genetics

OBJECTIVETo investigate the effects of burn sera on the nuclear translocation of endothelial NF-kappaB heterodimers p50/p65 and on the degradation of inhibiting kappaB (IkappaBalpha), in order to explore the role of burn sera on activation of the endothelium.

METHODSCultured human umbilical vein endothelial cells (HUVECs) (ECV-304 strain) were employed as the target cells. The cells were stimulated by sera from healthy volunteers and from burn patients and burn sera together with PDTC (pyrrolidine dithiocarbarnate). The normal cultured cells were taken as the control. The nuclear translocation of endothelial p50/p65 at 30, 60, 120 and 480 mins after the stimulation was observed with laser confocal microscopy, and the endothelial IkappaBalpha protein degradation at 30, 60, 90 and 120 mins after the stimulation was determined by Western blotting.

RESULTSWhen compared to that in control group, the nuclear translocation of p50/p65 took place 30 mins after the endothelial cells were stimulated by burn sera, and it reached the summit at 30 - 60 mins, but recovered to pre-stimulation state at 2hrs. In addition, IkBalpha degradation occurred 30 mins after the cells were stimulated by burn sera (P < 0.01) and peaking at 45 - 60 mins after the stimulation and recovered at 2hrs after the stimulation. The nuclear translocation of endothelial p50/p65 and IkBalpha degradation at 30 and 60 mins after the stimulation by burn sera could be effectively inhibited by PDTC.

CONCLUSIONBurn sera might induce the nuclear translocation of endothelial NF-kappaB p50/p65 and IkappaBalpha degradation and activate NF-kappaB, which ultimately lead to the secretion of cytokines from the endothelium.

Active Transport, Cell Nucleus ; Adolescent ; Adult ; Burns ; blood ; Female ; Humans ; I-kappa B Proteins ; analysis ; Male ; Middle Aged ; NF-KappaB Inhibitor alpha ; NF-kappa B ; metabolism ; NF-kappa B p50 Subunit ; Transcription Factor RelA

BACKGROUNDThe aim of this study was to explore whether the inhibition of nuclear factor-kappaB (NF-kappaB) activation by mutant IkappaBalpha (S32, 36-->A) can enhance TNF-alpha-induced apoptosis of leukemia cells and to investigate the possible mechanism.

METHODSThe mutant IkappaBalpha gene was transfected into HL-60 cells by liposome-mediated techniques. G418 resistant clones stably expressing mutant IkappaBalpha were obtained by the limiting dilution method. TNF-alpha-induced NF-kappaB activation was measured by electrophoretic mobility shift assay (EMSA). The expression of bcl-xL was detected by RT-PCR and Western blot after 4 hours exposure of parental HL-60 and transfected HL-60 cells to a variety of concentrations of TNF-alpha. The percentage of apoptotic leukemia cells was evaluated by flow cytometry (FCM).

RESULTSMutant IkappaBalpha protein was confirmed to exist by Western blot. The results of EMSA showed that NF-kappaB activation by TNF-alpha in HL-60 cells was induced in a dose-dependent manner, but was almost completely inhibited by mutant IkappaBalpha repressor in transfected cells. The levels of bcl-xL mRNA and protein in HL-60 cells increased after exposure to TNF-alpha, but changed very little in transfected HL-60 cells. The inhibition of NF-kappaB activation by mutant IkappaBalpha enhanced TNF-alpha-induced apoptosis. The cytotoxic effects of TNF-alpha were amplified in a time- and dose-dependent manner.

CONCLUSIONSNF-kappaB activation plays an important role in the resistance to TNF-alpha-induced apoptosis. The inhibition of NF-kappaB by mutant IkappaBalpha could provide a new approach that may enhance the anti-leukemia effects of TNF-alpha or even of other cytotoxic agents.

Apoptosis ; drug effects ; Gene Expression Regulation, Leukemic ; HL-60 Cells ; Humans ; I-kappa B Proteins ; physiology ; NF-KappaB Inhibitor alpha ; NF-kappa B ; antagonists & inhibitors ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; Tumor Necrosis Factor-alpha ; pharmacology ; bcl-X Protein