Inactivation Of NF-κB Signaling Pathway Research Articles

Adipocyte enhancer binding protein 1 knockdown alleviates osteoarthritis through inhibiting NF-κB signaling pathway-mediated inflammation and extracellular matrix degradation.

Inflammation promotes the degradation of the extracellular matrix, which contributes to the development of osteoarthritis (OA). Adipocyte enhancer binding protein 1 (AEBP1) participates in multiple pathological processes related to inflammatory diseases. However, the role of AEBP1 in OA development is unknown. We found a higher AEBP1 expression in articular cartilage of OA patients (n=20) compared to their normal controls (n=10). Thus, we inferred that AEBP1 might affect OA progression. Then mice with destabilization of the medial meniscus (DMM) surgery and chondrocytes with IL-1β treatment (10ng/mL) were used to mimic OA. The increased AEBP1 expression was observed in models of OA. AEBP1 knockdown in chondrocytes reversed IL-1β-induced inflammation and extracellular matrix degradation, which was mediated by the inactivation of NF-κB signaling pathway and the increased IκBα activity. Co-immunoprecipitation assay indicated the interaction between AEBP1 and IκBα. Importantly, IκBα knockdown depleted the protective role of AEBP1 knockdown in OA. Moreover, AEBP1 knockdown in mice with OA showed similar results to those in chondrocytes. Collectively, our findings suggest that AEBP1 knockdown alleviates the development of OA, providing a novel strategy for OA treatment.

A Lignan from Alnus japonica Activates Myogenesis and Alleviates Dexamethasone-induced Myotube Atrophy.

To find inhibitors against skeletal muscle loss, we isolated a lignan compound ((-)-(2R,3R-1,4-O-diferuloylsecoisolarciresinol, DFS) from the stem of Alnus japonica. C2C12 myoblasts were treated with DFS during differentiation. To induce an in vitro atrophic condition, differentiated myotubes were treated with dexamethasone (a synthetic glucocorticoid). DFS (10 nM) increased expression levels of myogenic factors and the number of multi-nucleated myotubes expressing myosin heavy chain (MHC). The myogenic potential of DFS could be attributed to p38 MAPK activation. DFS also protected against dexamethasone-induced damage, showing increased expression of MHC and mammalian target of rapamycin (mTOR), a major anabolic factor. Under atrophic condition, the anti-myopathy effect of DFS was associated with inactivation of NF-κB signaling pathway and the subsequent suppression of muscle degradative E3 ligases and myostatin. DFS treatment also restored fast muscle fiber (type II a, II b, and II x), known to be susceptible to dexamethasone. These results indicate that DFS isolated from A.japonica can stimulate myogenesis via p38 MAPK activation and alleviate muscle atrophy by modulating the expression of genes associated with muscle protein anabolism/catabolism. Thus, we propose that DFS can be used as a pharmacological and nutraceutical agent for increasing muscle strength or protecting muscle loss.

N-3 polyunsaturated fatty acids block the trimethylamine-N-oxide- ACE2- TMPRSS2 cascade to inhibit the infection of human endothelial progenitor cells by SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) is a novel coronavirus that infects many types of cells and causes cytokine storms, excessive inflammation, acute respiratory distress to induce failure of respiratory system and other critical organs. In this study, our results showed that trimethylamine-N-oxide (TMAO), a metabolite generated by gut microbiota, acts as a regulatory mediator to enhance the inerleukin-6 (IL-6) cytokine production and the infection of human endothelial progenitor cells (hEPCs) by SARS-CoV-2. Treatment of N-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) could effectively block the entry of SARS-CoV-2 in hEPCs. The anti-infection effects of N-3 PUFAs were associated with the inactivation of NF-κB signaling pathway, a decreased expression of the entry receptor angiotensin-converting enzyme 2 (ACE2) and downstream transmembrane serine protease 2 in hEPCs upon the stimulation of TMAO. Treatment of DHA and EPA further effectively inhibited TMAO-mediated expression of IL-6 protein, probably through an inactivation of MAPK/p38/JNK signaling cascades and a downregulation of microRNA (miR)-221 in hEPCs. In conclusion, N-3 PUFAs such as DHA and EPA could effectively act as preventive agents to block the infection of SARS-CoV-2 and IL-6 cytokine production in hEPCs upon the stimulation of TMAO.

Effect of Polysaccharide Sulfate-Loaded Poly(lactic-co-glycolic acid) Nanoparticles on Coronary Microvascular Dysfunction of Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DCM) mainly results from development of coronary microcirculatory dysfunction (CMD). Polysaccharide sulfate (PSS), as one heparin drug, has a variety of biological activities. This study examined the efficacy of a new type of PSS-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (PSS-NPs) on DCM, in finding a theoretical basis for CMD treatment. After establishment of DCM model, the animals were administrated with PSS, PSS-NPs, normal saline or poly(ethylene glycol)1 (PEG1) through intraperitoneal injection. 8 weeks after injection of streptozotocin (STZ), heart function of rats was assessed by echocardiography. The rat tissues were collected and detected by histological analysis. Quantitative reverse transcription PCR (RT-qPCR) and Western blot analyses determined the levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and pro-inflammatory factors. PSS-NPs had a good protective effect on cardiac insufficiency in rats. Administration of PSS-NPs prolonged survival state, and enhanced cardiac function, thereby alleviating the symptoms, and inducing formation of micro vessels. Importantly, it improved the symptoms of DCM patients and their quality of life. Moreover, pro-inflammatory factor levels decreased upon the treatment, accompanied with inactivation of NF-κB signaling pathways, thereby improving DCM. This study demonstrated that the PSS-NPs significantly relieved DCM and restored cardiac function in rats through NF-κB signaling pathways, providing a theoretical basis for development of PSS-NPs, and new treatment ideas for CMD of DCM.

Potential effect of astragaloside IV on the lipopolysaccharide induced inflammation via the inactivation of NF-κB signaling pathway

Background: The host treats lipopolysaccharides (LPS) as a sign of microbial invasion by pathogenic Gram-negative bacteria. In lungs, LPS activates a cascade of inflammatory reactions leading to inflammation. Previous investigation suggests that astragaloside IV (AG) has an anti-inflammatory and antioxidant effect, but the potential mechanism of lung inflammation is still unknown. In this experimental study, we aimed to investigate the anti-inflammatory potential of AG against LPS-induced lung inflammation. Materials and Methods: In this study, we used Sprague Dawley rats for the experimental protocol. Animals were injected with LPS (10 mg/kg, b. w.) for the induction of lung inflammation and were subsequently administered with AG (1.25, 2.5, and 5 mg/kg). At the end of the experiment, acute phase response and lipid parameters were estimated. Pro-inflammatory cytokines and inflammatory mediators were also estimated. Furthermore, quantitative real-time polymerase chain reaction was used to estimate the inflammatory markers and expression of mRNA of apoptosis markers. Results: AG treatment significantly increased the survival rate as compared to LPS control. AG significantly (P < 0.001) altered the renal, hepatic, lipid, and antioxidant parameter at dose dependent manner. AG significantly (P < 0.001) decreased the level of malondialdehyde and reduced glutathione and increased he activity of superoxide dismutase. AG significantly (P < 0.001) decreased the level of nuclear factor kappa B (NF-κB). In addition, AG significantly (P < 0.001) down-regulated the expression of inflammatory cytokines such as interleukin (IL)-1, IL-6, IL-1 β, tumor necrosis factor-α, IL-18 and upregulated the expression of IL-4 and IL-10. Conclusion: In summary, these findings indicate that AG effectively suppressed the LPS-induced inflammation through inactivation of NF-κB signaling pathway.

Deletion of Golgi protein 73 delayed hepatocyte proliferation of mouse in the early stages of liver regeneration.

Golgi protein 73 (GP73) is a transmembrane protein that can promote the proliferation of cancer cells. However, the roles of GP73 in the proliferation of non-malignant hepatocytes have rarely been investigated. The wild-type (GP73+/+ ) and GP73 gene knockout mice (GP73-/- ) were subject to 70% partial hepatectomy (PHx) to explore the involvement of GP73 in liver regeneration. After PHx, a significant increase of GP73 expression was observed in GP73+/+ mouse liver. Noticeably, promoted recovery of liver mass was observed in GP73-/- mouse at Day 1 after PHx, as showed by the liver/body weight ratio. RNA sequencing revealed that genes relevant to cell cycle and inflammation response in the residual liver tissues were severely suppressed with the deletion of GP73, particularly the inactivation of NF-κB signal pathway in early phase of liver regeneration. In line with this, we do see the downregulation of cell cycle-related protein including cyclin D1, p-cyclin D1, β-catenin, as well as interleukin 6, tumor necrosis factor-α, CCl2, and CXCl10. In contrast, activation of mTOR signaling pathway was documented, accompanied with the histological hypertrophy of hepatocytes in GP73-/- mouse. Golgi protein 73 deletion leads to delayed response of liver regeneration and inflammation in the early stages of liver regeneration after PHx.

Anti-inflammatory action of physalin A by blocking the activation of NF-κB signaling pathway

Ethnopharmacological relevancePhysalis Calyx seu Fructus is typically used to treat inflammatory diseases such as upper respiratory tract infection and acute tonsillitis in clinical practice of China. Physalin A, a main active ingredient of this traditional Chinese medicine (TCM), has been reported for its significant anti-tumor activity. However, most reports focused on the studies of its anti-tumor activity, the anti-inflammatory activity of physalin A and its molecular mechanism are still not elucidated clearly. Aim of the studyThe aim of the study was to investigate the anti-inflammatory activities both in vitro and in vivo and molecular mechanism of physalin A. Materials and methodsThe potential anti-inflammatory properties of physalin A were evaluated in vitro by lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells, and in vivo via two typical acute inflammation murine models. Some important inflammation-related molecules were analyzed by enzyme-linked immuno sorbent assay (ELISA) and Western blotting. ResultsThe results showed that physalin A inhibited carrageenan-induced paw edema of rats and capillary permeability of mice induced by acetic acid in vivo. Furthermore, physalin A also significantly reduced the release of inflammatory mediators nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor-α (TNF-α) induced by lipopolysaccharide (LPS) in RAW 264.7 in vitro. Further investigations indicated that physalin A can down-regulate the high expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner. Physalin A remarkably blocked the degradation of inhibitor of nuclear factor kappa B alpha (IκB-α) and the nuclear translocation of nuclear factor-κB (NF-κB) p65 induced by LPS in RAW 264.7 cells. However, physalin A did not significantly inhibit the phosphorylation of mitogen-activated protein kinases (MAPKs) family proteins c-Jun N-terminal kinase (JNK) or extracellular signal-regulated kinase (ERK) or p38. ConclusionsAll the results clearly illustrated that the anti-inflammatory action of physalin A is due to the inactivation of NF-κB signal pathway, but is irrelevant to the MAPKs pathway.

Anti-Inflammatory Effect of Simonsinol on Lipopolysaccharide Stimulated RAW264.7 Cells through Inactivation of NF-κB Signaling Pathway.

Simonsinol is a natural sesqui-neolignan firstly isolated from the bark of Illicium simonsii. In this study, the anti-inflammatory activity of simonsinol was investigated with a lipopolysaccharide (LPS)-stimulated murine macrophages RAW264.7 cells model. The results demonstrated that simonsinol could antagonize the effect of LPS on morphological changes of RAW264.7 cells, and decrease the production of nitric oxide (NO), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) in LPS-stimulated RAW264.7 cells, as determined by Griess assay and enzyme-linked immunosorbent assay (ELISA). Furthermore, simonsinol could downregulate transcription of inducible nitric oxide synthase (iNOS), TNF-α, and IL-6 as measured by reverse transcription polymerase chain reaction (RT-PCR), and inhibit phosphorylation of the alpha inhibitor of NF-κB (IκBα) as assayed by Western blot. In conclusion, these data demonstrate that simonsinol could inhibit inflammation response in LPS-stimulated RAW264.7 cells through the inactivation of the nuclear transcription factor kappa-B (NF-κB) signaling pathway.

MiR-29a inhibits invasion and metastasis of cervical cancer via modulating methylation of tumor suppressor SOCS1.

Aims: To investigate roles of miR-29a-DNMT1-SOCS1 axis in cervical cancer invasion and migration. Materials & methods: The methylation level of SOCS1 was determined by methylation specific PCR. The cell apoptosis, proliferation, migration and invasion were examined by Annexin-V/PI staining, MTT and colony formation assays, plus scratch and transwell assays respectively. The expressions of epithelial-mesenchymal transition and NF-κB related proteins were determined by western blotting. Results: MiR-29a was downregulated, accompanied with DNMT1 upregulation and SOCS1 downregulation in cervical cancer tissues. MiR-29a suppressed DNMT1, inhibited SOCS1 promoter methylation and upregulated its expression. Moreover, miR-29a promoted cell apoptosis, suppressed proliferation, inhibited migration and invasion via inactivation of NF-κB signaling pathway in cervical cancer cells. Conclusion:MiR-29a-DNMT1-SOCS1 axis plays an important role on invasion and metastasis in cervical cancer via NF-κB signaling pathway.

Trimetazidine Attenuates Exhaustive Exercise-Induced Myocardial Injury in Rats via Regulation of the Nrf2/NF-κB Signaling Pathway.

Exhausted exercise has been reported to cause the damage of myocardial structure and function in terms of cardiomyocyte apoptosis, oxidative stress, and energy metabolism disturbance. Trimetazidine (TMZ), as an anti-ischemic agent, has been approved to be effective in promoting myocardial energy metabolism, anti-inflammatory, and anti-oxidation. However, few studies examined the effects of TMZ on myocardial injury induced by exhausted exercise. To investigate whether TMZ could ameliorate the exhaustive exercise-induced myocardial injury and explore the underlying mechanisms, here the rat model of exhaustive exercise was induced by prolonged swimming exercise and TMZ was administrated to rats before exhaustive exercise. According to the results, we demonstrated that exhaustive exercise led to cardiomyocyte damage in rats as evidenced by elevations in cTnI and NT-proBNP levels, and decrease in CX43 expression, which was attenuated by TMZ treatment. Moreover, the administration of TMZ was found to restrain exhaustive exercise-induced oxidative stress damage by increasing GSH level, SOD and GSH-Px activities, and decreasing MDA level. Additionally, TMZ ameliorated myocardial injury by inhibiting apoptosis via reducing Bax/Bcl-2 ratio and down-regulating cleaved caspase-3, cleaved PARP, and cytochrome c levels in the myocardium of rats. Furthermore, we found that TMZ suppressed oxidative stress and cardiomyocyte apoptosis via activation of Nrf2/HO-1 and inactivation of NF-κB signaling pathways. Therefore, our study suggested that TMZ provided cardioprotection in rats after exhaustive exercise, indicating TMZ might served as a potential therapeutic drug for exhaustive exercise-induced myocardial injury.

Enhanced chemosensitivity of cholangiocarcinoma cell line QBC939 to gemcitabine induced by curcumin

Objective To investigate the effect of curcumin in enhancing chemosensitivity of cholangiocarcinoma cell line QBC939 to gemcitabine and its mechanism. Methods QBC939 cells were divided into control group, 5 μmol/L curcumin group, 0.625 μg/ml gemcitabine group and 5 μmol/L curcumin combined 0.625 μg/ml gemcitabine group. Methyl thiazol tetrazolium (MTT) assay was used to detect the proliferation inhibition effect, flow cytometry was used to detected the change of cell cycle and apoptosis rate. Expressions of nuclear factor-κB (NF-κB), Cyclin B1 and inhibitor of apoptosis proteins (IAP)-1 in different groups were detected by Western blotting. Results Compared with control group, curcumin group and gemcitabine group, the inhibitory rates of cells in curcumin combined gemcitabine group at 12, 24, 48 and 72 h were (10.00±0.02)%, (23.10±0.03)%, (33.23±0.01)%, (48.30±0.05)% respectively, which were significantly higher than those of control group and single medicaments treatment group (P=0.001, 0.000, 0.000, 0.000); besides, curcumin combined with gemcitabine blocked (28.75±3.23)% human cholangiocarcinoma cell line QBC939 in G2/M phase, which was significantly higher than those of curcumin group and gemcitabine group [(14.49±2.20)%, (11.82±2.10)%; P=0.000], the apoptosis rate in combined group was (13.64±3.40)%, significantly higher than those of control group, curcumin group and gemcitabine group [(4.53±0.56)%, (6.47±0.98)%, (9.87±1.12)%; P=0.000]; moreover, the relative expression levels of NF-κB and its downstream moleculor Cyclin B1 and IAP-1 proteins in curcumin combined with gemcitabine group were 0.300±0.001, 0.407±0.036, 0.475±0.032 respectively, significantly lower than those of control group, curcumin group and gemcitabine group (P=0.000, 0.001, 0.003). Conclusion Curcumin can enhance the sensitivity of human cholangiocarcinoma cell line QBC939 to gemcitabine through the inactivation of NF-κB signaling pathway. Key words: Cholangiocarcinoma cell; Curcumin; Gemcitabine; Cholangiocarcinoma cell line QBC939; Nuclear factor-κB

Loss of virulence in NAD(P)H cytochrome b5 oxidoreductase deficient Leishmania major

Leishmania promastigotes have the ability to synthesize essential polyunsaturated fatty acids de novo and can grow in lipid free media. Recently, we have shown that NAD(P)H cytochrome b5 oxidoreductase (Ncb5or) enzyme in Leishmania acts as the redox partner for Δ12 fatty acid desaturase, which catalyses the conversion of oleate to linoleate. So far, the exact role of Leishmania derived linoleate synthesis is still incomplete in the literature. The viability assay by flow cytometry as well as microscopic studies suggests that linoleate is an absolute requirement for Leishmania promastigote survival in delipidated media. Western blot analysis suggested that infection with log phase linoleate deficient mutant (KO) results in increased level of NF-κBp65, IκB and IKKβ phosphorylation in RAW264.7 cells. Similarly, the log phase KO infected RAW264.7 cells show dramatic increment of COX-2 expression and TNF-α secretion, compared to control or Ncb5or complement (CM) cell lines. The activation of inflammatory signaling pathways by KO mutant is significantly reduced when the RAW264.7 cells are pre-treated with BSA bound linoleate. Together, these findings confirmed that the leishmanial linoleate inhibits both COX-2 and TNF-α expression in macrophage via the inactivation of NF-κB signaling pathway. The stationary phase of KO promastigotes shows avirulence after infection in macrophages as well as inoculation into BALB/c mice; whereas CM cell lines show virulence. Collectively, these data provide strong evidence that de novo linoleate synthesis in Leishmania is an essential for parasite survival at extracellular promastigote stage as well as intracellular amastigote stage.

Ligustrazine protects chondrocyte against IL-1β induced injury by regulation of SOX9/NF-κB signaling pathway.

Ligustrazine is extracted from rhizoma ligustici wallichii, is known for its vasodilatory properties in the traditional Chinese herbal medicine. The study aimed to determine the effect and the underlying mechanism of ligustrazine on interleukin-1β (IL-1β)-induced injury in osteoarthritis (OA). Human articular cartilages and joint effusion were obtained from patients with OA, and the chondrocytes were isolated and treated with IL-1β. The different inflammatory cytokines were analyzed by ELISA. Cell viability, apoptosis, and apoptosis-related factors were examined by MTT, flow cytometry, and Western blot. Then, the expressions of COL2A1 and ACAN, and the concentrations of sGAG and MMP-13 were measured. The level of SOD and MDA and ROS production were then analyzed. Furthermore, the protein levels of SOX9 and NF-κB pathway were detected by Western blot. Ligustrazine significantly suppressed inflammatory reaction in joint effusion of OA patients. Moreover, ligustrazine attenuated IL-1β-induced chondrocytes injury and matrx degradation in chondrocytes. Ligustrazine promoted oxidative stress response by increasing SOD level, decreasing MDA level, and inhibiting ROS production in IL-1β-induced chondrocytes. Besides, ligustrazine increased SOX9 expression, and SOX9 silencing reversed the effect of ligustrazine on matrx degradation in IL-1β-injured chondrocytes. Furthermore, ligustrazine blocked NF-κB pathway in IL-1β-induced chondrocytes, and PTDC (NF-κB inhibitor) enhanced the effect of ligustrazine on viability, apoptosis, SOX9 expression, and ROS production in IL-1β-induced chondrocytes. These results indicated that ligustrazine protected chondrocytes against IL-1β-induced injury possibly by regulation of SOX9 and inactivation of NF-κB signaling pathway. It could act as a therapeutic agent for the treatment of OA.

Halofuginone attenuates intervertebral discs degeneration by suppressing collagen I production and inactivating TGFβ and NF-кB pathway

Most low back pain is caused by intervertebral discs (IVD) degeneration, a disease that prevalence is increasing with age. Halofuginone, an analog of ferbrifugine isolated from plant Dichroa febrifuga, has drawn much attention in recent years for the wide range of bioactivities in malaria, cancer, fibrotic and autoimmune diseases. In this study, we evaluated the benefit effects of halofuginone in IVD degeneration treatment in a validated rabbit puncture model. Halofuginone treatment could attenuate disc degeneration by suppressing the decrease of discs height and nucleus pulposus signal strength. Besides, halofuginone treatment could suppress mRNA and protein expression of collagen I in nucleus pulposus. This might possibly due to the inactivation of transform growth factor-β (TGFβ) signal pathway by down-regulating p-Samd3 and up-regulating inhibitory Smad7. Then, we evaluated the effects of halofuginone treatment on nuclear factor of kappa B (NF-κB) signal pathway and its downstream pro-inflammatory cytokines. The level of p-p65 and p-IκBα was down-regulated in halofuginone treated group, indicating the inactivation of NF-κB signal pathway. The mRNA expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and interleukin 8 (IL-8) was decreased in nucleus pulposus too, indicating the down-regulation of pro-inflammatory cytokines. In conclusion, halofuginone treatment could attenuate IVD degeneration and this was possibly due to suppressing of collagen I production and inactivation of TGFβ and NF-κB signal pathway in nucleus pulposus of degenerated discs. These results suggest that halofuginone has the potential for IVD degeneration treatment, but more research is needed to validate this.

MiR-143 suppresses the osteogenic differentiation of dental pulp stem cells by inactivation of NF-κB signaling pathway via targeting TNF-α

BackgroundDental pulp stem cells (DPSCs) are multipotent and play an important role in repairing damaged and/or defective dentinogenesis/osteogenesis. Recent studies have documented the implication of miR-143 in osteogenic differentiation of DPSCs. Nevertheless, the detailed mechanisms of miR-143 involved in the osteogenic differentiation of DPSCs remain to be further elaborated. MethodsIsolated DPSCs were incubated with osteogenic differentiation medium to induce osteogenic differentiation. qRT-PCR and western blot were performed to determine the expressions of miR-143 and tumor necrosis factor α (TNF-α). Luciferase reporter assay was used to confirm whether TNF-α was a target of miR-143. Osteogenic differentiation of DPSCs was evaluated by alkaline phosphatase (ALP) activity assay, ALP staining, and western blot analyses of osteogenic-markers including bone morphogenetic protein 2 (BMP2), ALP, runt-related transcription factor 2 (RUNX2) and collagen type I (COLI). ResultsmiR-143 was downregulated and TNF-α was upregulated during osteogenic differentiation of DPSCs. miR-143 posttranscriptionally regulated TNF-α expression in DPSCs by binding to its 3′UTR. miR-143 overexpression suppressed osteogenic differentiation of DPSCs, as demonstrated by the decrease of ALP activity, ALP positive cell ratio, as well as BMP2, ALP, RUNX2, and COLI expressions. Moreover, miR-143 reversed TNF-α-induced osteogenic differentiation of DPSCs. Finally, the osteogenic differentiation of DPSCs induced by miR-143 inhibitor was attenuated following inactivation of nuclear factor kappa B (NF-κB) signaling pathway. ConclusionmiR-143 suppressed the osteogenic differentiation of DPSCs by blockade of NF-κB signaling pathway via targeting TNF-α.

Paclitaxel alleviated liver injury of septic mice by alleviating inflammatory response via microRNA-27a/TAB3/NF-κB signaling pathway

Excessive inflammatory response and apoptosis play an important role in the sepsis-induced liver injury. Paclitaxel, a diterpene alkaloid of Taxus brevifolia, is widely used as an anti-tumor drug and shows protective effects on acute lung and kidney injury. However, whether it has a protective effect against sepsis-induced liver injury has not been reported. The objective of this study was to investigate the protective effects of paclitaxel in septic liver injury in mice and associated molecular mechanisms. Our results showed that paclitaxel treatment improved LPS-induced liver injury, as evidenced by the reduced aminotransferase activity, histological scores and apoptosis in the liver tissues. This was accompanied by the alleviating of inflammation and oxidative stress, such as decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and malondialdehyde (MDA) and increased levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) in serum and liver tissues. Subsequent microarray and qRT-PCR analysis further showed that miR-27a was significantly decreased in mice with sepsis, which was recovered by paclitaxel pretreatment. Antagomir-miR-27a suppressed the therapeutic effects of paclitaxel in mice liver injury model via promoting inflammatory response. Of note, TAB3, which participated in the activation of the NF-κB signaling pathway, was identified as a direct target of miR-27 by luciferase reporter gene assays. Then, we revealed a reverse relationship between miR-27a expression levels and TAB3 mRNA levels in liver tissues from septic mice. Furthermore, paclitaxel treatment significantly decreased the expression of NF-κB p65, but increased inhibitor of nuclear factor-κB-α (IκBα) protein levels in septic mice, suggesting the inactivation of NF-κB signaling pathway. Notably, the inhibitory effects of paclitaxel on NF-κB signaling pathway were reversed by antagomir-miR-27a. Our data indicated that paclitaxel significantly attenuated septic induced liver injury through reducing inflammatory response via miR-27a/TAB3/NF-κB signaling pathway.

Morin, a Bioflavonoid Suppresses Monosodium Urate Crystal-Induced Inflammatory Immune Response in RAW 264.7 Macrophages through the Inhibition of Inflammatory Mediators, Intracellular ROS Levels and NF-κB Activation.

Our previous studies had reported that morin, a bioflavanoid exhibited potent anti-inflammatory effect against adjuvant-induced arthritic rats. In this current study, we investigated the anti-inflammatory mechanism of morin against monosodium urate crystal (MSU)-induced inflammation in RAW 264.7 macrophage cells, an in vitro model for acute gouty arthritis. For comparison purpose, colchicine was used as a reference drug. We have observed that morin (100–300 μM) treatment significantly suppressed the levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1 and VEGF), inflammatory mediators (NO and PEG2), and lysosomal enzymes (acid phosphatase, β-galactosidase, N-acetyl glucosamindase and cathepsin D) in MSU-crystals stimulated macrophage cells. The mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and MCP-1), inflammatory enzymes (iNOS and COX-2), and NF-κBp65 was found downregulated in MSU crystal stimulated macrophage cells by morin treatment, however, the mRNA expression of hypoxanthine phospho ribosyl transferse (HPRT) was found to be increased. The flow cytometry analysis revealed that morin treatment decreased intracellular reactive oxygen species levels in MSU crystal stimulated macrophage cells. The western blot analysis clearly showed that morin mainly exerts its anti-inflammatory effects by inhibiting the MSU crystal-induced COX-2 and TNF-α protein expression through the inactivation of NF-κB signaling pathway in RAW 264.7 macrophage cells similar to that of BAY 11–7082 (IκB kinase inhibitor). Our results collectively suggest that morin can be a potential therapeutic agent for inflammatory disorders like acute gouty arthritis.

Cadherin-17 induces tumorigenesis and lymphatic metastasis in gastric cancer through activation of NFκB signaling pathway

Cadherin-17 (CDH17), as a structurally unique member of the cadherin superfamily, has been identified to predict a poor prognosis for gastric cancer (GC). Our previous study demonstrated the positive correlation between CDH17 and lymph node micrometastasis in GC. We sought to further identify the role of CDH17 in the tumorigenesis and lymphatic metastasis of GC. Hence, we inhibited the CDH17 expression in MKN-45 gastric cancer cells by using RNA interference. Consequently, the malignant potency of cancer cells was evaluated, and the change in NFκB signaling pathway was also probed. Tumor growth and lymphatic metastasis model were conducted in nude mice to confirm the hypothesis. Downregulation of CDH17 not only suppressed the proliferation, adherence and invasion potency of MKN-45 cells, but also induced cell cycle arrest. Meanwhile, the NFκB signaling pathway was inactivated as well, with the reductions of downstream proteins including VEGF-C and MMP-9. Moreover, silencing CDH17 inhibited tumor growth in vivo significantly, and there was no lymph node metastasis detected in the mice without CDH17 expression, as opposed to the positive nodes found in controls. CDH17 is a novel oncogene in gastric cancer cells, which is associated with lymphatic metastasis and proliferation strongly. The inactivation of NFκB signaling pathway might be involved in targeting CDH17 in GC. On the whole, CDH17 is proposed to serve as a biomarker and attractive therapeutic target in GC.

Abstract 1932: Bortezomib sensitizes malignant human glioma cells to histone deacetylase inhibitors depends on reactive oxygen species production, mitochondrial dysfunction, Noxa upregulation and Mcl-1 cleavage

Abstract Glioblastomas are invasive tumors with poor prognosis despite current therapies. Unfortunately, individual targeted therapies have failed to offer long-term survival benefit. Histone deacetylase inhibitors (HDACIs) represent a class of agents that can modulate gene expression to reduce tumor growth. Suberoylanalide hydroxamic acid (SAHA, vorinostat) and LBH-589 are inhibitors of several members of the HDAC family, and we and others have noted some antiglioma activity, although insufficient to warrant use as single-agent therapy. Proteasome inhibitors represent a promising class of anticancer agents, already in clinical use, as bortezomib (PS-341/Velcade) has been approved for the treatment of multiple myeloma with inactivation of NF-κB signaling pathway. We have recently demonstrated that bortezomib exhibited potent anti-glioma activity and dramatically sensitized highly resistant glioma cells to TRAIL cytotoxicity, suggesting that proteasomal inhibition may be a promising combination strategy for glioma therapeutics. In this study, we examined whether bortezomib could enhance response to HDAC inhibition in glioma cells. These studies showed that bortezomib enhanced vorinostat and LBH-589-induced apoptosis in malignant glioma cells. Although vorinostat or LBH-589 treatment alone did not induce apoptosis in glioma cells, efficacy was enhanced by addition of bortezomib, which promoted activation of proapoptotic mitochondrial injury, generation of ROS, and inhibition of the prosurvival NF-κB signaling pathway. Our results also revealed that cotreatment with bortezomib and vorinostat enhanced apoptosis by increasing Mcl-1, Noxa cleavage and other pro-apoptotic protein expression. The significantly enhanced antitumor activity that results from the combination of bortezomib and HDACIs offers promise as a novel treatment for glioma patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1932. doi:10.1158/1538-7445.AM2011-1932

Molecular Evidence for Increased Antitumor Activity of Gemcitabine by Genistein In vitro and In vivo Using an Orthotopic Model of Pancreatic Cancer

Soy isoflavone genistein exhibits growth inhibitory activity against human pancreatic cancer cell lines. We previously reported the potential of genistein to augment chemotherapeutic response of pancreatic cancer cells in vitro. In the present study, we investigated whether genistein pretreatment could be used as a novel strategy for gemcitabine-induced killing in vitro and enhanced antitumor activity in vivo using an orthotopic tumor model. We conducted our studies using paired isogenic human pancreatic cancer cell line with differences in metastatic behavior (COLO 357 and L3.6pl). In vitro studies were done to measure growth inhibition and degree of apoptotic cell death induced by either genistein alone, gemcitabine alone, or genistein followed by gemcitabine. Our results show that pretreatment of cells with genistein for 24 hours followed by gemcitabine resulted in 60% to 80% growth inhibition compared with 25% to 30% when gemcitabine was used alone. The overall growth inhibition was directly correlated with apoptotic cell death irrespective of the metastatic potential of cells. Several genes that are known to inhibit apoptosis and contribute to chemoresistance such as nuclear factor-kappaB (NF-kappaB) and Akt were assessed to investigate the basis for the observed chemosensitizing effects of genistein. Genistein potentiated the gemcitabine-induced killing by down-regulation of NF-kappaB and Akt. In contrast, Akt and NF-kappaB were found to be up-regulated when pancreatic cancer cells were exposed to gemcitabine alone, suggesting the potential mechanism of acquired chemoresistance. In addition to in vitro results, we show here for the first time, that genistein in combination with gemcitabine is much more effective as an antitumor agent compared with either agent alone in our orthotopic tumor model. But most importantly, our data also showed that a specific target, such as NF-kappaB, was inactivated in genistein-treated animal tumors and that gemcitabine-induced activation of NF-kappaB was completely inhibited in animal tumors treated with genistein and gemcitabine. These results provide strong molecular in vivo evidence in support of our hypothesis that inactivation of NF-kappaB signaling pathway by genistein could also abrogate gemcitabine-induced activation of NF-kappaB resulting in the chemosensitization of pancreatic tumors to gemcitabine, which is likely to be an important and novel strategy for the treatment of pancreatic cancer.