Role Of Tumor Necrosis Factor Research Articles

The Dual Role of Tumor Necrosis Factor (TNF) in Cancer Biology

Tumor necrosis factor (TNF) is a cytokine with well known anticancer properties and is being utilized as anticancer agent for the treatment of patients with locally advanced solid tumors. However, TNF role in cancer biology is debated. In fact, in spite of the wealth of evidence supporting its antitumor activity, the cascade of molecular events underlying TNF-mediated tumor regression observed in vivo is still incompletely elucidated. Furthermore, some preclinical findings suggest that TNF may even promote cancer development and progression. With this work we intend to summarize the molecular biology of TNF (with particular regard to its tumor-related activities) and review the experimental and clinical evidence currently available describing the complex and sometime apparently conflicting relationship between this cytokine, cancer biology and antitumor therapy. We also propose a model to explain the dual effect of TNF based on the exposure time and cytokine levels reached within the tumor microenvironment. Finally, we overview recent research findings that might lead to new ways for exploiting the anticancer potential of TNF in the clinical setting.

PKCζ decreases eNOS protein stability via inhibitory phosphorylation of ERK5

AbstractPKCζ has emerged as a pathologic mediator of endothelial cell dysfunction, based on its essential role in tumor necrosis factor α (TNFα)–mediated inflammation. In contrast, extracellular signal–regulated kinase 5 (ERK5) function is required for endothelial cell homeostasis as shown by activation of Krüppel-like factor 2 (KLF2), increased endothelial nitric-oxide synthase (eNOS) expression, and inhibition of apoptosis. We hypothesized that protein kinase C ζ (PKCζ) activation by TNFα would inhibit the ERK5/KLF2/eNOS pathway. TNFα inhibited the steady laminar flow–induced eNOS expression, and this effect was reversed by the dominant-negative form of PKCζ (Ad.DN-PKCζ). In addition, ERK5 function was inhibited by either TNFα or the transfection of the catalytic domain of PKCζ. This inhibition was reversed by PKCζ small interfering RNA. PKCζ was found to bind to ERK5 under basal conditions with coimmunoprecipitation and the mammalian 2-hybrid assay. Furthermore, PKCζ phosphorylates ERK5, and mutation analysis showed that the preferred site is S486. Most importantly, we found that the predominant effect of TNFα stimulation of PKCζ was to decrease eNOS protein stability that was recapitulated by transfecting Ad.ERK5S486A mutant. Finally, aortic en face analysis of ERK5/PKCζ activity showed high PKCζ and ERK5 staining in the athero-prone region. Taken together our results show that PKCζ binds and phosphorylates ERK5, thereby decreasing eNOS protein stability and contributing to early events of atherosclerosis.

Role of tumor necrosis factor α (TNFα) in the onset of fructose-induced nonalcoholic fatty liver disease in mice

Tumor necrosis factor α (TNFα) is known to be involved in dysregulation of hepatic lipid metabolism and insulin signaling. However, whether TNFα also plays a casual role in the onset of fructose-induced nonalcoholic fatty liver disease (NAFLD) has not yet been determined. Therefore, wild-type and TNFα receptor 1 (TNFR1)−/− mice were fed with either 30% fructose solution or plain tap water. Hepatic triglycerides, markers of inflammation and ATP concentration as well as plasma ALT levels were determined. Hepatic PAI-1, SREBP-1, FAS mRNA expression was assessed by real-time RT-PCR. Furthermore, lipid peroxidation and indices of insulin resistance were determined in liver tissue and plasma. In comparison to water controls, chronic intake of 30% fructose solution caused a significant ∼5-fold increase in triglyceride accumulation and neutrophil infiltration in livers of wild-type mice and a ∼8-fold increase in plasma ALT levels. In TNFR1−/− mice, hepatic steatosis was attenuated and neutrophil infiltration in the liver as well as plasma ALT levels was similar to water controls. The protective effect of the TNFR1 deletion against the onset of fructose-induced steatosis was associated with increased phospho AMPK and Akt levels, decreased SREBP-1 and FAS expression in the liver and decreased RBP4 plasma levels, whereas hepatic lipid peroxidation, iNOS protein and ATP levels were similar between wild-type and TNFR1−/− mice fed fructose. Taken together, these data suggest that TNFα plays a casual role in the onset of fructose-induced liver damage as well as insulin resistance in mice through signaling cascades downstream of TNFR1.

Type I Pityriasis Rubra Pilaris: Upregulation of Tumor Necrosis Factor α and Response to Adalimumab Therapy

pityriasis rubra pilaris (PRP) has unknown etiology and is often refractory to conventional therapies. to document a PRP patient's response to adalimumab therapy and to highlight the potential role of tumor necrosis factor (TNF) in the development of PRP skin lesions. a patient received adalimumab therapy at standard dosing intervals. In addition, the messenger ribonucleic acid (mRNA) of TNF in the lesional and perilesional normal skin was quantified in two patients with PRP. the patient responded to adalimumab therapy and achieved clinical remission by 4 months. There was a significant elevation of TNF mRNA in the lesional skin of PRP. TNF upregulation is detected in PRP lesional skin, consistent with the observed clinical efficacy of TNF blockade for the treatment of PRP.

Tumour necrosis factor-α affects blood-brain barrier permeability and tight junction-associated occludin in acute liver failure

Cerebral oedema leading to cerebral herniation is a major cause of death during acute liver failure (ALF), but the underlying mechanism is not clear. We investigated the role of tumour necrosis factor (TNF)-alpha in changing the permeability of the blood-brain barrier (BBB) during ALF. ALF animal models were generated by administering D-galactosamine (GalN) and lipopolysaccharide, or GalN and TNF-alpha. ALF induction was blocked by first administering anti-TNF-alpha-IgG or anti-TNF-alpha-R1. We investigated the BBB permeability with Evans blue staining, and the structure with electron microscopy. BBB permeability increased in ALF mice and correlated with elevated serum TNF-alpha levels. No vascular endothelial cell (EC) apoptosis was detected, but electron microscopy of cells from human and mouse ALF tissues revealed tight junction (TJ) disruptions and EC shrinkage, as well as increased vesicles and vacuoles. In addition, the expression of the TJ-associated protein occludin was significantly decreased in both ALF mice and patients, although the expression of occludin mRNA did not change. Changes in BBB permeability, brain tissue ultrastructure and occludin expression in ALF-induced mice could be prevented by prophylaxis treatment with either antibody to TNF-alpha-IgG or antibody to TNF-alpha-R1. Our results suggest that TNF-alpha plays a critical role in the development of brain oedema in ALF, and that both vasogenic and cytotoxic mechanisms may be involved. Increased BBB permeability may be because of the disruption of TJs, and loss of the TJ-associated protein occludin.

TNFα is a key mediator of the pronociceptive effects of mucosal supernatant from human ulcerative colitis on colonic DRG neurons

ObjectivesAbdominal pain is a serious cause of morbidity in patients with inflammatory bowel disease. To better understand the mechanisms and potentially identify new targets for treatment, the effects of inflammatory...

Investigation of the role of tumour necrosis factor-α, interleukin-1β, interleukin-10, nitric oxide and rheumatoid factor-immunoglobulin M in a rat model of arthritis

Collagen-induced arthritis (CIA) in rats is a widely used preclinical animal model of rheumatoid arthritis (RA). However, CIA development in Sprague-Dawley (SD) rats is less severe in terms of inflammatory response compared with other strains. Therefore, a modified CIA model called MCIA, using N-acetylmuramyl dipeptide (MDP), has been developed in the less sensitive SD rat strains. This work was conducted to better understand the immunopathological role and contributions of the pro-inflammatory T-helper type 1 (Th-1) cytokines and inflammatory mediators, interleukin-1 (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO); the anti-inflammatory T-helper type 2 (Th-2) cytokine, IL-10 and autoantibodies such as rheumatoid factor (RF)-immunoglobulin M (IgM) in this newly developed RA model. TNF-alpha, NO and RF-IgM levels were significantly increased, while IL-1beta levels were not affected in this MCIA rat model. The levels of IL-10 were lower than the baseline when compared with controls. (1) the immunological features represented in the MCIA rat model favour the Th-1 cytokine profile over Th-2 and (2) RF-IgM can be used as a diagnostic test in preclinical RA models.

PO-91 Leptin upregulates human breast cancer cell line MCF7 expression of tissue factor: a possible role of tumor necrosis factor

PO-91 Leptin upregulates human breast cancer cell line MCF7 expression of tissue factor: a possible role of tumor necrosis factor

Blocking TRAIL-DR5 signaling with soluble DR5 reduces delayed neuronal damage after transient global cerebral ischemia

Mechanisms underlying delayed selective neuronal death after global cerebral ischemia remain to be clarified. Here, we report a critical role for tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in the pathogenesis of cerebral ischemia. C57BL/6j mice were subjected to transient global brain ischemia. RT-PCR and immunohistochemistry showed that the expression of TRAIL and DR5 was upregulated following transient ischemia–reperfusion. Dual immunofluorescence analysis indicated that TRAIL expression was significantly more pronounced in astrocytes and activated microglia/macrophages, whereas DR5 expression was more pronounced in neurons, which had a good correlation with the distribution of apoptotic cells. Treatment with soluble DR5 reduced ischemic cell death after transient global ischemia through blocking the interaction of endogenous TRAIL with DR5. These results indicate that TRAIL plays a deleterious role in the pathogenesis of delayed neuronal damage after global cerebral ischemia and inhibition of TRAIL function in the brain may represent a novel neuroprotective strategy to treat ischemic stroke.

Differential Role of Tumor Necrosis Factor (TNF)-α Receptors in the Development of Choroidal Neovascularization

Tumor necrosis factor alpha (TNF)-alpha contributes to inflammation-associated angiogenesis. This study investigates the role of TNF-alpha receptors 1a and 1b in the development of choroidal neovascularization (CNV). CNV was induced in Tnfrsf1a(-/-) and Tnfrsf1b(-/-) mice with C57Bl6/J background and their wild-type (WT) (C57Bl/6J) controls by laser damage to the Bruch's membrane. TNF-alpha expression in RPE/choroid was determined by Western blot analysis. Pathologic angiogenesis was estimated qualitatively and quantitatively by fluorescein angiography and histology on choroidal flat mounts and paraffin cross-sections. Inflammatory cell invasion was investigated by clodronic acid depletion of circulating macrophages and immunochemistry, and the apoptotic activity was investigated by TUNEL assay and by caspase-3 and caspase-8 expression. Receptor 1b-specific Bmx/Etk kinase was detected by immunochemistry. TNF-alpha levels were elevated after laser treatment. Severe CNV lesions and increased macrophage invasion were observed in Tnfrsf1a(-/-) compared with WT and Tnfrsf1b(-/-) mice. Increased immunoreactivity for Bmx/Etk kinase corresponded to the severity of CNV formation. Reduced pathologic angiogenesis and macrophage invasion in Tnfrsf1b(-/-) mice (vs. WT and Tnfrsf1a(-/-)) was accompanied by enhanced endothelial cell apoptosis and by caspase-3 and caspase-8 activation. Receptor 1b promotes the recruitment of inflammatory cells to the site of injury and exacerbated pathologic angiogenesis probably by way of the Bmx/Etk-kinase-dependent pathway in the absence of receptor 1a. On the other hand, receptor 1a-dependent apoptosis in the absence of receptor 1b leads to reduced inflammatory response and CNV lesions after laser treatment. This demonstrates the potential for specific targeting of TNF-alpha receptors for future therapies of inflammation-associated choroidal neovascularization.

Aspects of TNF inhibitor therapy in rheumatoid arthritis

Treatment outcomes in rheumatoid arthritis (RA) have improved considerably with the use of biological therapies. Since the discovery of the role of tumor necrosis factor (TNF) alpha in the pathogenesis of the disease, three TNF inhibitors, infliximab, etanercept and adalimumab, have become widely used for the treatment of RA. More recently, two newer TNF inhibitors-certolizumab pegol and golimumab-have become available, increasing the armamentarium of therapy. With improved therapies, treatment strategies have also changed, with the aims now being to achieve and maintain remission. This article addresses some of these aspects of treating RA, reviewing the studies on these two newer TNF inhibitors, certolizumab pegol and golimumab, and those addressing the induction of remission or low disease activity with TNF inhibitors and maintenance with less intensive treatment.

Analysis of TNFR2-mediated functions on osteoclast precursor cells

The role of tumour necrosis factor (TNF) in the induction and maintenance of human rheumatoid arthritis is well established. However, the role of its two receptors, especially of TNFR2, is...

Early production of tumor necrosis factor-α by Gr-1+cells and its role in the host defense to pneumococcal infection in lungs

In this study, we elucidated the role of tumor necrosis factor (TNF)-alpha in the host defense to pulmonary infection with Streptococcus pneumoniae and defined the cellular source of this cytokine at an early stage of infection. Administration of anti-TNF-alpha monoclonal antibody (mAb) resulted in the reduced accumulation of neutrophils in bronchoalveolar lavage fluids (BALFs) and severe exacerbation of this infection. In a flow cytometric analysis, the intracellular expression of TNF-alpha was detected in Gr-1(bright+) and Gr-1(dull+) cells during the time intervals postinfection, and F4/80(+) cells expressed intracellular TNF-alpha before Gr-1(dull+) cells appeared. The Gr-1(bright+) and Gr-1(dull+) cells sorted from BALF cells at 24 h were identified as neutrophils and macrophage-like cells, respectively, and the Gr-1(dull+) cells expressing CD11c, partially CD11b and a marginal level of F4/80 secreted TNF-alpha in in vitro cultures. Finally, deletion of Gr-1(+) cells by administration of the specific mAb significantly reduced the concentrations of this cytokine in BALF at 6 and 12 h postinfection, but not the expression of TNF-alpha in F4/80(+) cells. Thus, these results demonstrated that neutrophils, F4/80(+) macrophages and Gr-1(dull+) CD11c(+) macrophage-like cells played an important role in the production of TNF-alpha in lungs at an early stage of infection with S. pneumoniae.

Role of tumor necrosis factor-.ALPHA. in acute hepatitis B virus infection

Tumor necrosis factor (TNF)-α is one of the most important factors in HBV infection and HBV infection-related diseases. Although TNF-α is critical and beneficial in HBV clearance, the liver injury is progressed by the up-regulation of TNF-α production. Taken together, TNF-α contribute to the cure and increase of severity in acute hepatitis caused by HBV. It is very important to understand the role of TNF-α, which has two-wedge sword in HBV infection, and the mechanism of TNF-α production. This review briefly overviews up to date about the role of TNF-α in HBV-induced liver injury and HBV clearance, including our results achieved recently.

Effect of etanercept in polymyalgia rheumatica: a randomized controlled trial

IntroductionTo elucidate in polymyalgia rheumatica (PMR) the role of tumor necrosis factor (TNF) α and the therapeutic potential of blockade with soluble TNF-α receptor, we carried out the first randomized controlled trial with etanercept in PMR.MethodsTwenty newly diagnosed, glucocorticoid (GC) naïve patients with PMR and 20 matched non-PMR control subjects completed the trial. Subjects were randomized in a 1:1 ratio to monotherapy with etanercept (25 mg s.c. biweekly) or placebo (saline) for 14 days. Study outcomes were assessed at baseline and after 14 days. The primary outcome was the change in PMR activity score (PMR-AS). Secondary outcomes were: changes in erythrocyte sedimentation rate (ESR) and plasma levels of TNF-α and interleukin (IL) 6; patients' functional status (health assessment questionnaire) and cumulative tramadol intake during the trial.ResultsAt baseline, plasma TNF-α was higher in patients than in controls (P < 0.05). The concentration always increased with etanercept treatment (P < 0.05). In patients, etanercept decreased PMR-AS by 24% (P = 0.011), reflecting significant improvements in shoulder mobility, physician's global assessment and C-reactive protein, and insignificant (P > 0.05) improvements in duration of morning stiffness and patient's assessment of pain. In parallel, ESR and IL-6 were reduced (P < 0.05). Placebo treatment did not change PMR-AS, ESR and IL-6 (P > 0.05). Functional status did not change and tramadol intake did not differ between patient groups. In controls, no changes occurred in both groups.ConclusionsEtanercept monotherapy ameliorates disease activity in GC naïve patients with PMR. However, the effect is modest, indicating a minor role of TNF-α in PMR.Trial registrationClinicalTrials.gov (NCT00524381).

P3.050 Role of tumor necrosis factor in the progressive phase of dopaminergic neuron death in a rat model of Parkinson's disease

P3.050 Role of tumor necrosis factor in the progressive phase of dopaminergic neuron death in a rat model of Parkinson's disease

Cytokines as Targets for Anti‐inflammatory Agents

Well over a decade ago a central role of tumor necrosis factor (TNF) was first described in patients with rheumatoid arthritis (RA) when remarkable clinical benefit was demonstrated in patients with refractory disease were treated with using either a monoclonal antibody or a soluble receptor fusion protein. There are now five anti-TNF agents approved by regulatory agencies for treating RA. Identifying which RA patients will have a meaningful clinical response (improvement in outcomes measures such as ACR 20, DAS score, remission, etc.) when used as monotherapy, or in combination with other immunosuppressive agents remains a major research effort. Also, attention has focused on the potential adverse events that can be seen with these therapies; an increase in opportunistic infections being the most clearly linked adverse event. These anti-TNF therapies have revolutionized the clinicians' ability to make a significant impact in RA, a disease that has significant excess morbidity and mortality.

Cytokines and clustered cardiovascular risk factors in children

The aim was to evaluate the possible role of tumor necrosis factor α (TNF- α), interleukin-6 (IL-6), C-reactive protein (CRP), low fitness, and fatness in the early development of clustering of cardiovascular disease (CVD) risk factors and insulin resistance. Subjects for this cross-sectional study were obtained from 18 schools near Copenhagen, Denmark. Two hundred ten 9-year-old children were selected for cytokine analysis from 434 third-grade children with complete CVD risk profiles. The subgroup was selected according to the CVD risk factor profile (upper and lower quartile of a composite CVD risk score). All the CVD risk factors and CRP differed between the high- and low-risk groups; but plasma glucose, TNF- α, and IL-6 had small and inconsistent differences. Strong associations were found between CVD risk scores and fitness (VO 2peak) or fatness. No associations were found between CVD risk scores and TNF- α and IL-6. C-reactive protein was associated with fitness, fatness, and CVD risk score. This study does not support an association between plasma IL-6 or TNF- α and low insulin sensitivity or clustering of CVD risk factors in a young cohort. Inflammation was more pronounced in fat and unfit children based on the association with CRP levels. The association between fitness and fatness variables, insulin resistance, and clustered risk could be caused by other mechanisms related to these exposures. The role of IL-6 remains unclear.

Independent and Additive Interactive Effects Among Tumor Necrosis Factor-α Polymorphisms, Substance Use Habits, and Chronic Hepatitis B and Hepatitis C Virus Infection on Risk for Hepatocellular Carcinoma

We conducted a case-control study to assess the roles of tumor necrosis factor (TNF)-alpha polymorphisms, substance use habits, and chronic hepatitis B virus (HBV)/hepatitis C virus (HCV) infection on the risk for hepatocellular carcinoma (HCC). We enrolled 200 pairs of sex- and age-matched patients with HCC and unrelated healthy controls. TNF-alpha polymorphisms were detected with polymerase chain reaction and direct sequencing. Serum hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCV) were detected. We used a structured questionnaire to obtain information about substance use habits.Multivariate analysis indicated that TNF308.2 allele (odds ratio [OR], 3.23; p = 0.011), habitual betel quid chewing (OR, 3.70; p = 0.011), HBsAg (OR, 23.62; p = 0.0001), and anti-HCV (OR, 38.73; p = 0.0001) were independent risk factors for HCC. Having at least 2 substance use habits was associated with risk for HCC. The more substance use habits, the higher the OR for HCC (p(for trend) = 0.0001). There were additive interactions among TNF308.2 allele, substance use habits, and chronic HBV/HCV infection. Multivariate analysis indicated that TNF308.2 allele (p = 0.001), cigarette smoking (p = 0.0001), and alcohol drinking (p = 0.0001) were independent risk factors for habitual betel quid chewing. Moreover, patients harboring the TNF308.2 allele and/or those with habits of substance use had low serum albumin concentration and platelet count (each p = 0.0001). In conclusion, there are independent and additive interactive effects among the TNF308.2 allele, substance use habits, and chronic HBV/HCV infection on the risk for HCC. Substance use habits or carrying the TNF308.2 allele correlates with disease severity and hepatic fibrosis, which may contribute to higher risks for HCC.

British Association of Dermatologists’ guidelines for biologic interventions for psoriasis 2009

St John’s Institute of Dermatology, King’s College London and Guy’s and St Thomas’ NHS Foundation Trust, London SE1 9RT U.K. *Department of Dermatology, Royal Gwent Hospital, Newport NP20 2UB, U.K. Department of Dermatology, Western Infirmary, Glasgow G11 6NT, U.K. The Dermatology Centre, Salford Royal Hospital, University of Manchester, Manchester Academic Health Science Centre, Manchester M6 8HD, U.K. §Psoriasis and Psoriatic Arthritis Alliance, PO Box 111, St Albans AL2 3JQ, U.K. –Department of Dermatology, Cardiff University, School of Medicine, Heath Park, Cardiff CF14 4XN, U.K. **Royal National Hospital for Rheumatic Diseases, Bath BA1 1RL, U.K. Department of Dermatology, Belfast City Hospital, Belfast BT9 7AB, U.K. Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K. §§Department of Dermatology, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB9 2ZB, U.K.