Gene therapy that inhibits NF-κB results in apoptosis of human hepatocarcinoma by recombinant adenovirus

AIM: To investigate whether the recombinant adenovirus induces the TNF-α-mediated apoptosis in vivo.METHODS: Human hepatocarcinoma cell line (HepG2)cells were transfected into BALB/c nude mice, and the tumor growth curve was drawn. We analyzed apoptosis in HepG2 cells by TUNEL, HE staining and electron microscopy.RESULTS: AdIκBαM was expressed stably and efficiently in HepG2 and could not be degraded by induction of TNF-α. Tumor growth in mice could be reduced remarkably if treated by AdIκBαM plus TNF-α. There was apoptosis of ＞ 70% of cells treated with AdIκBαM plus TNF-α and about 50% of cells treated with AdIκBαM. In contrast, there was few cell apoptosis in HepG2 cells treated with phosphate buffered saline and AdIκBα. HepG2 cells in mice also exhibited a high level of apoptosis after in vivo injection with AdIκBαM. The tumor growth curve indicated the tumor transfected with AdIκBαM could be restrained.CONCLUSION: AdIκBαM gene therapy greatly enhances apoptosis due to inhibition of an NF-κB-mediated antiapoptosis signaling pathway.     

Anti-inflammatory effects of bifidobacteria by inhibition of LPS-induced NF-κB activation

AIM: Different strains of bifidobacteria were analysed for their effects on HT-29 intestinal epithelial cells (IECs) in in vitro models both of the non-inflamed and inflamed intestinal epithelium. METHODS: A reporter gene system in HT-29 cells was used to measure levels of NF-KB activation after challenge with bifidobacteria or after bacterial pre-treatment following LPS challenge. IL-8 protein and pro-inflammatory gene expression was investigated using normal HT-29 cells. RESULTS: None of the bifidobacteria tested induced activation of nuclear factor KB (NF-KB) indicating that bifidobacteria themselves do not induce inflammatory events in IECs. However, six out of eight bifidobacteria tested inhibited lipopolysaccharide- (LPS-) induced NFKB activation in a dose- and strain-dependent manner. In contrast, NF-KB activation in response to challenge with tumor necrosis factor-α(TNF-α) was affected by none of the tested bifidobacteria, indicating that the inhibitory effect of bifidobacteria is specific for LPS-induced inflammation in IECs. As shown with two of the six inhibitionpositive bifidobacteria, LPS-induced inhibition of NFKB activation was accompanied by a dose-dependent decrease of interleukin 8 (IL-8) secretion and by lower mRNA levels for IL-8, TNF-a, cyclooxygenase 2 (Cox-2), and intercellular adhesion molecule 1 (ICAM-1). CONCLUSION: Some strains of bifidobacteria are effective in inhibiting LPS-induced inflammation and thus might be appropriate candidates for probiotic intervention in chronic intestinal inflammation.     

Anti-inflammatory effects of bifidobacteria by inhibition of LPS-induced NF-κB activation

AIM: Different strains of bifidobacteria were analysed for their effects on HT-29 intestinal epithelial cells (IECs) in in vitro models both of the non-inflamed and inflamed intestinal epithelium. METHODS: A reporter gene system in HT-29 cells was used to measure levels of NF-kappaB activation after challenge with bifidobacteria or after bacterial pre-treatment following LPS challenge. IL-8 protein and pro-inflammatory gene expression was investigated using normal HT-29 cells. RESULTS: None of the bifidobacteria tested induced activation of nuclear factor kappaB (NF-kappaB) indicating that bifidobacteria themselves do not induce inflammatory events in IECs. However, six out of eight bifidobacteria tested inhibited lipopolysaccharide- (LPS-) induced NF-kappaB activation in a dose- and strain-dependent manner. In contrast, NF-kappaB activation in response to challenge with tumor necrosis factor-alpha (TNF-alpha) was affected by none of the tested bifidobacteria, indicating that the inhibitory effect of bifidobacteria is specific for LPS-induced inflammation in IECs. As shown with two of the six inhibition-positive bifidobacteria, LPS-induced inhibition of NF-kappaB activation was accompanied by a dose-dependent decrease of interleukin 8 (IL-8) secretion and by lower mRNA levels for IL-8, TNF-alpha, cyclooxygenase 2 (Cox-2), and intercellular adhesion molecule 1 (ICAM-1). CONCLUSION: Some strains of bifidobacteria are effective in inhibiting LPS-induced inflammation and thus might be appropriate candidates for probiotic intervention in chronic intestinal inflammation.     

Hepatic preconditioning of doxorubicin in stop-flow chemotherapy:NF-κB/IκB-α pathway and expression of HSP72

AIM: To provide hepatic protection through administration of doxorubicin before stop-flow chemotherapy (SFC) and to investigate the expression of heat shock protein 72 (HSP72) and role of nuclear factor kappa B (NF-κB) in this effect. METHODS: The hepatic preconditioning of doxorubicin was established in a porcine model by injection of doxorubicin (1 mg/kg) before SFC. The experimental animals were randomized into two groups: groups receiving doxorubicin (DOX) and normal saline (NS). Serial serum and tissue samples were taken from both groups to evaluate the protection of doxorubicin. Western blot and immunoprecipitation were applied to detect the expression of HSP72, NF-κB p65 protein, inhibitor κB-α (IκB-α) and phosphorylated IκB-α as well. The expression of tumor necrosis factor α (TNF-α) was estimated by semiquantitative RT-PCR. And the extent of the hepatic injury was estimated with the level of serum aminotransferases. RESULTS: An abundance production of HSP72 in porcine liver was observed after 24 h of intravenous administration of doxorubicin, but without any change in the expression of NF-κB p65 subunit in cytoplasm. NF-κB p65 subunit accumulated in nuclei at the end of SFC and reached its highest level at 30 min after the restoration of the abdominal circulation and decreased gradually during the 6 h after SFC in NS group, while there was little change in DOX group. There was also a slight decrease of IκB-α at 30 min after the restoration of the abdominal circulation in NS group accompanying with the appearance of phosphorylated IκB-α. The expression of TNF-α was significantly higher in NS group than that in DOX group (average 1.40±0.17 vs 0.62±0.22, P<0.01) at serial time points after SFC. Serum ALT and AST levels of NS group were higher after 24 h than those of DOX group (93.2±7.8 IU/L vs 53.3±13.9 IU/L, 217.0±29.4 IU/L vs 155.0±15.6 IU/L for ALT and AST respectively, P<0.05) and after 48 h than those of DOX group (66.6±18.1 IU/L vs 43.3±16.7 IU/L, 174.4±21.3 IU/L vs 125.7±10.5 IU/L for ALT and AST respectively, P<0.05). CONCLUSION: Doxorubicin renders the liver to be tolerant to the hepatic influence in SFC in a porcine model through the NF-κB/IκB-αpathway with the expression of HSP72.     

亚砷酸联合重组腺病毒Ad-IκBαM对肝细胞癌的治疗作用

目的:观察感染Ad-IκBαM对NF-κB激活的抑制及对亚砷酸诱导肝癌细胞凋亡的增强效应,探讨亚砷酸对肝癌细胞的治疗作用.方法:选择人肝癌细胞系BEL-7402和SMMC-7721,以不同浓度亚砷酸处理.制备重组腺病毒Ad-IκBαM,用来转染经和未经亚砷酸处理的肝癌细胞.MTT和TUNEL方法观察各组细胞生长及凋亡情况;应用EMSA及Western blot研究肝癌细胞核内NF-κB的激活情况和感染Ad-IκBαM对NF-κB激活的抑制效果.结果:MTT结果表明各浓度亚砷酸对肝癌细胞的作用较正常肝细胞显著(P＜0.01);Western blot和EMSA结果提示亚砷酸可明显抑制肝癌细胞生长,使细胞内NF-κB系统活化;感染重组腺病毒Ad-IκBαM的肝癌细胞后,亚砷酸引起的NF-κB的激活受到明显抑制.亚砷酸联合Ad-IκBαM或Ad-IκBα作用于肝癌细胞SMMC-7721的凋亡指数分别为66.47%和36.67%;亚砷酸联合Ad-IκBαM或Ad-IκBα作用于肝癌细胞Bel-7402的凋亡指数分别为74.5%和32.37%.结论:亚砷酸对肝癌细胞有明显的杀灭作用,同时激活了肝癌细胞内的NF-κB;应用重组腺病毒Ad-IκBαM可以有效抑制NF-κB的激活,并可明显增强亚砷酸对肝癌细胞的作用.     

NF-κB通路与帕金森病

帕金森病的发病机制有MAPK、NF-κB、PKC、NO和NOS等多种信号转导通路的参与,而这螳信号转导通路均通过调控细胞凋亡而参与帕会森病的发病。本文主要从NF-κB与帕金森病的关系予以综述。     

EGCG经NF-κB途径抑制肝癌HepG2细胞增殖的研究

目的 初步探讨EGCG抑制肝癌HepG2细胞增殖的作用机制.方法 通过绘制细胞生长曲线、平皿克隆和软琼脂集落形成实验观察EGCG对HepG2细胞增殖的抑制作用;Western blot检测NF-κB P65蛋白的表达.结果 细胞生长曲线、平皿克隆和软琼脂集落形成实验结果显示,EGCG可有效抑制HepG2细胞的增殖(n=3,P＜0.05).Western blot检测结果显示,EGCG处理后NF-κB P65蛋白表达降低.结论 EGCG通过抑制HepG2细胞中NF-κB P65蛋白表达发挥其对细胞增殖的抑制作用.     

NF-κB在肺间质纤维化中的作用

核因子 κB(NF κB)是一个结合DNA的蛋白因子家族 ,参与许多前炎症介质分子转录水平的调控 ,包括细胞因子 (如IL 1β、TNF a、IL 6、IL 8、TGF等 )、粘附分子 (ICVA 1/CD54、ECVA 1/E 选择素、CCVA 1/CD10 6)、酶 (诱导型一氧化氮合成酶、环氧合酶 2 )。这些分子大多是促进肺间质性疾病发展的重要因子。     

Hepatic preconditioning of doxorubicin in stop-flow chemotherapy：NF-kB／IkB-α pathway and expression of HSP72

AIM: To provide hepatic protection through administration of doxorubicin before stop-flow chemotherapy (SFC) and to investigate the expression of heat shock protein 72(HSP72) and role of nuclear factor kappa B (NF-kB) in this effect.METHODS: The hepatic preconditioning of doxorubicin was established in a porcine model by injection of doxorubidn(1 mg/kg) before SFC. The experimental animals were randomized into two groups: groups receiving doxorubicin(DOX) and normal saline (NS). Serial serum and tissue samples were taken from both groups to evaluate the protection of doxorubicin. Western blot and immunoprecipitation were applied to detect the expression of HSP72, NF-kB p65 protein, inhibitor kB-α (IkB-α) and phosphorylated IkB-α as well. The expression of tumor necrosis factor α (TNF-α) was estimated by semiquantitative RT-PCR. And the extent of the hepatic injury was estimated with the level of serum aminotransferases.RESULTS: An abundance production of HSP72 in porcine liver was observed after 24 h of intravenous administration of doxorubicin, but without any change in the expression of NF-kB p65 subunit in cytoplasm. NF-kB p65 subunit accumulated in nuclei at the end of SFC and reached its highest level at 30 rain after the restoration of the abdominal circulation and decreased gradually during the 6 h after SFC in NS group, while there was little change in DOX group. There was also a slight decrease of IkB-α at 30 min after the restoration of the abdominal circulation in NS group accompanying with the appearance of phosphorylated IkB-α. The expression of TNF-α was significantly higher in NS group than that in DOX group (average 1.40&#177;0.17 vs 0.62&#177;0.22, P&lt;0.01) at serial time points after SFC. Serum ALT and AST levels of NS group were higher after 24 h than those of DOX group (93.2&#177;7.8 IU/L vs 53.34&#177;13.9 IU/L,217.0&#177;29.4 IU/L vs 155.0&#177;15.6 IU/L for ALT and AST respectively, P&lt;0.05) and alter 48 h than those of DOX group (66.6&#177;18.1 IU/L vs 43.3&#177;16.7 IU/L, 174.4&#177;21.3 IU/Lvs 125.7&#177;10.5 IU/L for ALT and AST respectively, P&lt;0.05).CONCLUSION: Doxorubicin renders the liver to be tolerant to the hepatic influence in SFC in a porcine model through the NF-kB/IkB-α pathway with the expression of HSP72.     

3-Hydroxyanthranilic acid inhibits PDK1 activation and suppresses experimental asthma by inducing T cell apoptosis

3-Hydroxyanthranilic acid (HAA), a compound generated during tryptophan metabolism initiated by indoleamine 2,3-dioxygenase, is known to induce T cell death, but its molecular target is not known. Here we report that HAA inhibits NF-kappaB activation upon T cell antigen receptor engagement by specifically targeting PDK1. Inhibition of NF-kappaB by HAA leads to dysfunction and cell death of activated Th2 cells, which in turn suppresses experimental asthma. Inhibition of NF-kappaB and induction of apoptosis is specific to CD4 T cells because HAA does not inhibit NF-kappaB activation or induce cell death upon Toll-like receptor 4 stimulation in dendritic cells. Thus, HAA is a natural inhibitor that restrains T cell expansion and activation.     

NIK overexpression amplifies, whereas ablation of its TRAF3-binding domain replaces BAFF:BAFF-R-mediated survival signals in B cells

BAFF-R-dependent activation of the alternative NF-κB pathway plays an essential role in mature B cell survival. Mutations leading to overexpression of NIK and deletion of the TRAF3 gene are implicated in human multiple myeloma. We show that overexpression of NIK in mouse B lymphocytes amplifies alternative NF-κB activation and peripheral B cell numbers in a BAFF-R-dependent manner, whereas uncoupling NIK from TRAF3-mediated control causes maximal p100 processing and dramatic hyperplasia of BAFF-R-independent B cells. NIK controls alternative NF-κB signaling by increasing the protein levels of its negative regulator TRAF3 in a dose-dependent fashion. This mechanism keeps NIK protein levels below detection even when they cause B cell hyperplasia, so that contributions of NIK to B cell pathologies can easily be overlooked.     

Epstein-Barr latent membrane protein 1 transformation site 2 activates NF-kappaB in the absence of NF-kappaB essential modifier residues 133-224 or 373-419

Epstein Barr virus latent membrane protein 1 (LMP1) induces NF-κB activation through transformation effector sites (TES) 1 and 2, both of which are critical for B-lymphocyte transformation. TES2 principally activates canonical NF-κB, which we confirm is NF-κB essential modifier (NEMO)-dependent and requires an intact ubiquitin binding in A20 binding inhibitor of NF-κB and NEMO (UBAN) domain. LMP1 TES2 activated NF-κB in Jurkat cell lines harboring NEMO truncated at 372 (A45) or NEMO with an in-frame deletion of 133-224 (2C), whereas TNFα, 12-O-Tetradecanoylphorbol-13-acetate, human T-cell leukemia virus 1 Tax, and CD40 did not. In both A45 and 2C Jurkat cell lines, LMP1 TES2-mediated NF-κB activation was blocked by siRNAs to TNFα receptor-associated factor 6 and NEMO, by IκB kinase inhibitors, and by the IκBα superrepressor, indicating that the NEMO mutants function to support canonical NF-κB activation. Expression of A45 or 2C mutants in NEMO-deficient murine embryonic fibroblasts reproduced the Jurkat phenotypes: LMP1 TES2 activated NF-κB in fibroblasts lacking NEMO amino acids 133-224 or 373-419, but TNFα and Tax did not. Further analysis indicated that TES2 did not activate NF-κB in cells expressing the double deletion mutant Δ133-224/Δ372-419. These data provide further evidence of the essential role for NEMO in LMP1 TES2 NF-κB activation and highlight the importance of unique domains within NEMO for sensing distinct NF-κB stimuli.     

Cortex cinnamomi extract prevents streptozotocin- and cytokine-induced β-cell damage by inhibiting NF-κβ

AIM: To clarify the mechanism underlying the anti-diabetic activities of cortex cinnamomi extract (CCE). METHODS: To induce in vivo diabetes, mice were injected with streptozotocin (STZ) via a tail vein (100 mg STZ/kg body weight). To determine the effects of CCE, mice were administered CCE twice daily for 7 d by oral gavage starting 1 wk before the STZ injection. Blood glucose and plasma insulin concentration were measured as an index of diabetes. Also, to induce cytotoxicity of RINm5F cells, we treated with cytokines (IL-1beta (2.0 ng/mL) and IFN-gamma (100 U/mL)). Cell viability and nitric oxide production were measured colorimetrically. Inducible nitric oxide synthase (iNOS) mRNA and protein expression were determined by RT-PCR and Western blotting, respectively. The activation of NF-kappaB was assayed by using gel mobility shift assays of nuclear extracts. RESULTS: Treatment of mice with STZ resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by immunohistochemical staining of islets. However, the diabetogenic effects of STZ were completely prevented when mice were pretreated with CCE. The inhibitory effect of CCE on STZ-induced hyperglycemia was mediated through the suppression of iNOS expression. In rat insulinoma RINm5F cells, CCE completely protected against interleukin-1beta and interferon-gamma-mediated cytotoxicity. Moreover, RINm5F cells incubated with CCE showed significant reductions in interleukin-1beta and interferon-gamma-induced nitric oxide production and in iNOS mRNA and protein expression, and these findings correlated well with in vivo observations. CONCLUSION: The molecular mechanism by which CCE inhibits iNOS gene expression appears to involve the inhibition of NF-kappaB activation. These results reveal the possible therapeutic value of CCE for the prevention of diabetes mellitus progression.     

NEMO recognition of ubiquitinated Bcl10 is required for T cell receptor-mediated NF-kappaB activation

The mechanism by which the Carma1-Bcl10-MALT1 (CBM) complex couples T cell antigen receptor (TCR) signaling to IkappaB kinase (IKK) and NF-kappaB activation is not known. Here, we show that Bcl10 undergoes K63-linked polyubiquitination in response to T cell activation and subsequently binds NEMO, the regulatory subunit of IKK. This interaction requires the ubiquitin-binding activity of NEMO. The sites of Bcl10 ubiquitination were mapped to K31 and K63. Mutation of these residues did not affect TCR signaling-induced CBM complex assembly but prevented Bcl10 ubiquitination, NEMO binding, and NF-kappaB activation. Therefore, the regulated ubiquitination of Bcl10 and its recognition by NEMO are a critical link between the CBM complex, IKK recruitment, and NF-kappaB activation.