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Aim. Kuseonwangdogo is a traditional Korean immunomodulatory polyherbal prescription. However, there are no systemic findings on its complex immunomodulatory effects on in vivo models. In this study, we observed the immunomodulatory effects of Kuseonwangdogo-based mixed herbal formula aqueous extracts (MHFe) on cyclophosphamide- (CPA-) induced immunosuppression mouse model. Methods. In total, 60 male 6-week-old ICR mice (10 mice/group) were selected based on body weight 24 h after the second CPA treatment and used in this experiment. Twelve hours after the end of the last (fourth) oral administration of MHFe, the animals were sacrificed. Results. Following CPA treatment, a noticeable decrease in the body, thymus, spleen, and submandibular lymph node (LN) weights; white blood cell, red blood cell, platelet number, hemoglobin, and hematocrit concentrations; serum interferon-γ levels; splenic tumor necrosis factor-α, interleukin- (IL-) 1β, and IL-10 content; and peritoneal and splenic natural killer cell activities was observed. Depletion of lymphoid cells in the thymic cortex, splenic white pulp, and submandibular LN-related atrophic changes were also observed. However, these CPA-induced myelosuppressive signs were markedly and dose-dependently inhibited by the oral administration of 125, 250, and 500 mg/kg MHFe. Conclusion. MHFe can be a promising, potent immunomodulatory therapeutic agent for various immune disorders. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by progressive joint erosion. Tumor necrosis factor (TNF) antagonists are the most widely used biological disease-modifying anti-rheumatic drug in RA. However, there continue to be one third of RA patients who have poor or no response to TNF antagonists. Following consideration of the uncertainty of therapeutic effects and the high price of TNF antagonists, it is worthy to predict the treatment responses before anti-TNF therapy. According to the comparisons between the responders and non-responders to TNF antagonists by omic technologies, such as genomics, transcriptomics, proteomics, and metabolomics, rheumatologists are eager to find significant biomarkers to predict the effect of TNF antagonists in order to optimize the personalized treatment in RA. [ABSTRACT FROM AUTHOR]

This study aims to investigate the incidence of hepatitis B virus (HBV) reactivation in inflammatory arthritis (IA) patients with HBV infection using anti-tumor necrosis factor (TNF) agents and evaluate the efficacy of antiviral therapy in reducing the risk of viral reactivation in chronic HBV infection. IA patients using anti-TNF agents from six centers were enrolled. Their HBV infection conditions and ALT and HBV-DNA levels were monitored periodically. Among the six chronic hepatitis B patients, HBV reactivation was found in two patients without antivirus prophylaxis and no viral replication was detected in the other four patients with antivirus prophylaxis. In the 31 inactive carriers, the increase of viral load was detected in 6 of 22 (27.3 %) patients without antiviral prophylaxis, and there was no viral reactivation in the other 9 patients with antiviral prophylaxis. HBV reactivation was not found in the 50 patients with resolved HBV infection. It is suggested that anti-TNF therapy might increase the risk of HBV reactivation in patients with chronic HBV infection, and antiviral prophylaxis could effectively decrease the risk. Anti-TNF agents seem to be safe in patients with resolved HBV infection. [ABSTRACT FROM AUTHOR]

Fatty liver injury (or disease) is a common disease in farmed fish, but its pathogenic mechanism is not fully understood. Therefore the present study aims to investigate high-fat diet (HFD)-induced liver injury and explore the underlying mechanism in fish. The tilapia were fed on control diet and HFD for 90 days, and then the blood and liver tissues were collected to determine biochemical parameter, gene expression and protein level. The results showed that HFD feeding signally increased the levels of plasma aminotransferases and pro-inflammatory factors after 60 days. In liver and plasma, HFD feeding significantly suppressed antioxidant ability, but enhanced lipid peroxidation formation, protein oxidation and DNA damage after 60 or 90 days. Further, the Nrf2 pathway and antioxidative function-related genes were adversely changed in liver of HFD-fed tilapia after 60 and/or 90 days. Meanwhile, HFD treatment induced apoptosis via initiating mitochondrial pathway in liver after 90 days. Furthermore, after 90 days of feeding, the expression of genes or proteins related to JNK pathway and TLRs-Myd88-NF-κB pathway was clearly upregulated in HFD treatment. Similarly, the mRNA levels of inflammatory factors including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8 and IL-10 were also upregulated in liver of HFD-fed tilapia after 60 and/or 90 days. In conclusion, the current study suggested that HFD feeding impaired antioxidant defense system, induced apoptosis, enhanced inflammation and led to liver injury. The adverse influences of HFD in the liver might be due to the variation of Nrf2, JNK and TLRs-Myd88-NF-κB signaling pathways. • HFD feeding impairs Nrf2 pathway to weaken antioxidant defense system in liver of tilapia. • HFD feeding induces apoptosis via mitochondrial pathway. • HFD feeding activates JNK-NF-κB pathway and TLRs-MyD88-NF-κB pathway to mediate inflammatory response. [ABSTRACT FROM AUTHOR]

Administration of lipopolysaccharide (LPS) by various routes produces profound inflammatory pain hypersensitivity. However, the molecular events that induce this response remain largely uncharacterized. In the present study, we sought to elucidate the role of the Rho/Rho kinase (ROCK) pathway in the release of tumor necrosis factor-α (TNF-α) and interleukin 1β (IL-1β) following injection of LPS into the mouse paw, which is associated with nociceptive behavior. The spinal cord of LPS-treated mice showed increased active GTP-bound RhoA and upregulation of ROCK2 and c-fos compared to the normal saline group. Furthermore, the inflammation-related cytokines TNF-α and IL-1β were markedly increased in the spinal dorsal horn after intraplantar injection of LPS. However, the latter effects were prevented by prophylactic intrathecal administration of the Rho inhibitor (C3 exoenzyme) or the ROCK inhibitor (Y27632). Collectively, our results suggest that the Rho/ROCK signaling pathway plays a critical role in LPS-induced inflammatory pain and that this pathway is coincident with the release of the pro-nociceptive cytokines TNF-α and IL-1β, which produces hyperalgesia. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine that causes endothelial dysfunction. Endocytosis of TNF-α receptors (TNFR) precedes endosomal reactive oxygen species (ROS) production, which is required for NF-κB activation in vascular smooth muscle cells. It is unknown how endocytosis of TNFRs impacts signaling in endothelial cells. We hypothesized that TNF-α-induced endothelial dysfunction is induced by both endosomal and cell surface events, including NF-κB and mitogen-activated protein kinases (MAPKs) activation, and endocytosis of the TNFR modifies signaling. Mesenteric artery segments from C57BL/6 mice were treated with TNF-α (10 ng/ml) for 22 h in tissue culture, with or without signaling inhibitors (dynasore for endocytosis, SP600125 for JNK, SB203580 for p38, U0126 for ERK), and vascular function was assessed. Endothelium-dependent relaxation to acetylcholine (ACh) was impaired by TNF-α, and dynasore exacerbated this, whereas JNK or p38 inhibition prevented these effects. In cultured endothelial cells from murine mesenteric arteries, dynasore potentiated JNK and p38 but not ERK phosphorylation and promoted cell death. NF-κB activation by TNF-α was decreased by dynasore. JNK inhibition dramatically increased both the magnitude and duration of TNF-α-induced NF-κB activation and potentiated intercellular adhesion molecule-1 (ICAM-1) activation. Dynasore still inhibited NF-κB activation in the presence of SP600125. Thus TNF-α-induced endothelial dysfunction is both JNK and p38 dependent. Endocytosis modulates the balance of NF-κB and MAPK signaling, and inhibition of NF-κB activation by JNK limits this pro-proliferative signal, which may contribute to endothelial cell death in response to TNF-α. [ABSTRACT FROM AUTHOR]

Both nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases mediate production of proinflammatory cytokines in many types of cells. c-Jun N-terminal kinases (JNK) is a key regulator of many cellular events including cell inflammation and/or programmed cell death (apoptosis). In addition to mediating immune and inflammatory responses, NF-κB transcription factors control cell survival. It is reported that activation of NF-κB antagonizes apoptosis or programmed cell death by numerous triggers. It has been reported that NF-κB activation results in rapid inactivation of JNK in tumor necrosis factor alpha (TNFα)-treated murine embryonic fibroblasts. It is not clear about the relationship of JNK and NF-κB in the microglial cells induced by TLR4 activity. In the present study, we investigated the relationship of JNK and NF-κB in the highly aggressively proliferating immortalized microglial cell line treated with KDO2 (a TLR4 agonist). KDO2 treatment significantly induced the phosphorylation of JNK and NF-κB, and released TNFα. Knockdown of TLR4 with TLR4 siRNA significantly reduced phosphorylation of JNK (pJNK), phosphorylation of NF-κB, and release of TNFα. Inhibition of JNK reduced the release of TNFα, but not phosphorylation of NF-κB. Unexpectedly, inhibition of NF-κB enhanced pJNK and the release of TNFα. These results showed that TNFα induced by KDO2 was JNK-dependent, and that NF-κB negatively modulated both pJNK and TNFα in the cultured microglial cell line. The current study may provide a new insight in the modulation of TNFα in the microglial cell line. [ABSTRACT FROM AUTHOR]

The zinc-finger protein A20 has crucial physiological functions as a dual inhibitor of nuclear factor-κB (NF-κB) activation and apoptosis in tumor necrosis factor (TNF) receptor 1 signaling pathway. Although the molecular basis for the anti-NF-κB function of A20 has been well elucidated, the anti-apoptotic function of A20 is largely unknown. Here, we report a novel mechanism underlying the anti-apoptotic function of A20: A20 blocks TNF-induced apoptosis through suppression of c-jun N-terminal kinase (JNK) by targeting apoptosis signal-regulating kinase1 (ASK1). First, the ectopic expression of A20 drastically inhibits TNF-induced JNK activation and apoptosis in multiple cell types including those deficient of NF-κB activation. Unexpectedly, the blunting effect of A20 on TNF-induced JNK activation is not mediated by affecting the TNFR1 signaling complex formation. Instead, A20 interacts with ASK1, an important MAPKK kinase in the JNK signaling cascade. More importantly, overexpression of wild-type A20, but not of mutant A20 (ZnF4; C624A, C627A), promotes degradation of the ASK1 through the ubiquitin-proteasome system. Taken together, the results from this study reveal a novel anti-apoptotic mechanism of A20 in TNF signaling pathway: A20 binds to ASK1 and mediates ASK1 degradation, leading to suppression of JNK activation and eventually blockage of apoptosis. [ABSTRACT FROM AUTHOR]

Liver diseases represent an important cause of morbidity and mortality in the world. Death of hepatocytes and other hepatic cell types is a characteristic feature of several forms of liver injury such as cholestasis, viral hepatitis, drug- or toxin-induced injury, and alcohol-induced liver damage. Moreover, irrespectively of the reason, liver injury seems to be facilitated by similar immune effector mechanisms common to these various liver diseases. Indeed, common immune effector mechanisms may explain the high prevalence of cirrhosis and cancer development in most forms of liver disease. Improved understanding of the immune cell-mediated mechanisms involved in hepatocyte cell death could be beneficial for the development of common therapeutic strategies against different forms of liver diseases. In this review, we will discuss novel findings on the role of different immune cells in liver disease and immune cell-induced death executioner mechanisms involved in hepatocyte cell death. [ABSTRACT FROM AUTHOR]

When administrated by isolated limb perfusion, tumor necrosis factor α (TNFα) is an efficient antitumor agent that improves drug penetration and destroys angiogenic vessels. Moreover, the pronounced potentiation of TNFα-induced apoptosis by NF-κB inhibitors suggest that these compounds could enhance TNFα antitumor efficacy through direct induction of tumor cell apoptosis. Therefore, attempts at amplifying signaling pathways that mediate TNFα antitumor effects could help to design combination therapies improving its efficiency. We report that nanomolar concentrations of all-trans retinoic acid (ATRA) amplify TNFα-induced apoptosis in APL cells expressing a specific repressor of NF-κB activation. This effect is abolished by the pan-caspase inhibitor, Z-VAD-fmk and by caspase-8 and -9 inhibitors. Cell death is accompanied by a drop of mitochondrial potential and by poly (ADP-ribose) polymerase (PARP) activation. Using specific PARP-1 inhibitors and siRNAs, we show that PARP-1 is essential for the synergistic apoptotic effect and c-Jun N-terminal kinase 1 (JNK1) activation triggered by the ATRA/TNFα combination. JNK1 siRNAs reduce ATRA/TNFα-induced apoptosis, mitochondrial release of cytochrome c and caspase-9 activation. Altogether, these results identify a novel mechanism of PARP-1-induced apoptosis, in which JNK1 provides a link between PARP-1 activation and mitochondrial pathway of caspase-9 activation. This study also suggests that inclusion of nanomolar doses of ATRA could be clinically beneficial in amplifying TNFα-induced antitumor signals.Oncogene (2008) 27, 3361–3370; doi:10.1038/sj.onc.1210997; published online 17 December 2007 [ABSTRACT FROM AUTHOR]

Background: We have previously shown that c-FLIPL is a more potent inhibitor than c-FLIPS of Fas ligand-induced apoptosis and that c-FLIPL physically binds to Daxx, an alternative Fas-signaling adaptor. Here we examined whether c-FLIPS effectively inhibits TNFR1-mediated apoptosis and triggers JNK activation through its interaction with TRAF2. Results: Some cancer cell lines, such as DU145, AGS, and PC3, have higher levels of c-FLIPS than other cell lines, such as SNU-719 and T24. The expression of c-FLIPS correlated with the susceptibility to TNFR1-mediated apoptosis. In contrast to DU145 and PC3, which are resistant to TNFR1-mediated apoptosis, T24 and SNU719 were sensitive to TNF-α treatment. To address the role of c-FLIPS in TNFR1-mediated apoptosis, we examined the molecular interaction between c-FLIPS and TRAF2. As expected, western blot analysis revealed that TRAF2 antibody immunoprecipitated a greater amount of c-FLIPS than c-FLIPL. Also, we measured the involvement of c-FLIPS in TNF-α-induced JNK activation and apoptosis by comparing these in TNF-α-resistant and TNF-α-sensitive cell lines. Treatment with TNF-α increased the phosphorylated JNK level in SNU719 and T24 cells, whereas DU145 and AGS cells were resistant to TNF-α-mediated apoptosis. Conclusion: We now report that the short form of c-FLIPS is a more efficient inhibitor of TNF-receptor 1-mediated apoptosis signaling than the long form of the protein. [ABSTRACT FROM AUTHOR]

Somatostatin is a multifunctional hormone that modulates cell proliferation, differentiation and apoptosis. Mechanisms for somatostatin-induced apoptosis are at present mostly unsolved. Therefore, we investigated whether somatostatin receptor subtype 2 (sst2) induces apoptosis in the nontransformed murine fibroblastic NIH3T3 cells. Somatostatin receptor subtype 2 expression induced an executioner caspase-mediated apoptosis through a tyrosine phosphatase SHP-1 (Src homology domain phosphatase-1)-dependent stimulation of nuclear factor kappa B (NF-κB) activity and subsequent inhibition of the mitogen-activated protein kinase JNK. Tumor necrosis factor α (TNFα) stimulated both NF-κB and c-Jun NH2-terminal kinase (JNK) activities, which had opposite action on cell survival. Importantly, sst2 sensitized NIH3T3 cells to TNFα-induced apoptosis by (1) upregulating TNFα receptor protein expression, and sensitizing to TNFα-induced caspase-8 activation; (2) enhancing TNFα-mediated activation of NF-κB, resulting in JNK inhibition and subsequent executioner caspase activation and cell death. We have here unraveled a novel signaling mechanism for a G protein-coupled receptor, which directly triggers apoptosis and crosstalks with a death receptor to enhance death ligand-induced apoptosis.Cell Death and Differentiation (2007) 14, 197–208. doi:10.1038/sj.cdd.4401939; published online 28 April 2006 [ABSTRACT FROM AUTHOR]

Inhibition of NF-κB activation increases susceptibility to tumor necrosis factor (TNF)α-induced cell death, concurrent with caspases and prolonged c-Jun N-terminal kinase (JNK) activation, and reactive oxygen species (ROS) accumulation. However, the detailed mechanisms are unclear. Here we show that cellular FLICE-inhibitory protein (c-FLIP) is rapidly lost in NF-κB activation-deficient, but not wild-type fibroblasts upon TNFα stimulation, indicating that NF-κB normally maintains the cellular levels of c-FLIP. The ectopic expression of the long form of c-FLIP (c-FLIPL) inhibits TNFα-induced prolonged JNK activation and ROS accumulation in NF-κB activation-deficient fibroblasts. Conversely, TNFα induces prolonged JNK activation and ROS accumulation in c-Flip−/− fibroblasts. Moreover, c-FLIPL directly interacts with a JNK activator, MAP kinase kinase (MKK)7, in a TNFα-dependent manner and inhibits the interactions of MKK7 with MAP/ERK kinase kinase 1, apoptosis-signal-regulating kinase 1, and TGFβ-activated kinase 1. This stimuli-dependent interaction of c-FLIPL with MKK7 might selectively suppress the prolonged phase of JNK activation. Taken that ROS promote JNK activation and activation of the JNK pathway may promote ROS accumulation, c-FLIPL might block this positive feedback loop, thereby suppressing ROS accumulation. [ABSTRACT FROM AUTHOR]

TNF-α activates several intracellular pathways to regulate inflammation, cell death, and proliferation. In the liver, TNF-a is not only a mediator of hepatotoxicity but also contributes to the restoration of functional liver mass by driving hepatocyte proliferation and liver regeneration. This review summarizes recent advances in TNF-α signaling mechanisms that demonstrate how the IKK, ROS, and JNK pathways interact with each other to regulate hepatocyte apoptosis and proliferation. Activation of these pathways is causatively linked to liver injury induced by concanavalin A, TNF-α, and ischemia-reperfusion and to liver regeneration and hepatocarcinogenesis. In light of recent findings, pharmacological inhibitors of JNK and IKK and antioxidants may be promising new tools for the treatment of hepatitis, ischemia-reperfusion injury, and hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor-a(TNFa) activates both cell death and cell survival pathways, which render most cancer cells resistant to its cytotoxicity. In this study, we found that pretreatment with luteolin, a plant flavonoid, greatly sensitized TNFa-induced apoptotic cell death in a number of human cancer cell lines; including colorectal cancer COLO205, HCT116 cells and cervical cancer HeLa cells. In the search of the molecular mechanisms responsible for the sensitization effect of luteolin, we discovered that luteolin inhibited TNFa-induced activation of nuclear transcription factor-kappa B (NF-?B), the main survival factor in TNFasignaling. As a result, luteolin suppressed the expression of NF-?B-targeted antiapoptotic genes, including A20 and cellular inhibitor of apoptosis protein-1 (c-IAP1). The role of A20 and c-IAP1 was further confirmed by ectopic expression of these two genes, which significantly protected cell death induced by luteolin followed by TNFa. In addition, inhibition of NF-?B by luteolin led to augmentation and prolongation of c-Jun N-terminal kinase (JNK) activation induced by TNFa. Suppression of JNK activation, either by a synthetic JNK inhibitor (SP600125) or by overexpression of the dominant negative forms of JNK kinase 1 (JNKK1) and JNK kinase 2 (JNKK2), conferred significant protection against apoptotic cell death induced by luteolin and TNFa, suggesting that NF-?B and JNK are closely associated with the sensitization effect of luteolin. Data from this study reveal a novel function of luteolin and enhance the value of luteolin as an anticancer agent.Oncogene (2004) 23, 7712-7721. doi:10.1038/sj.onc.1208046 Published online 30 August 2004 [ABSTRACT FROM AUTHOR]

Recent studies strongly suggest an active involvement of the c-Jun N-terminal kinase (JNK) signaling pathway in tumor necrosis factor (TNF)-induced apoptosis. The direct evidence for the role of JNK and its isoforms has been missing and the mechanism of how JNK actually could facilitate this process has remained unclear. In this study, we show that Jnk2-/- primary mouse embryonic fibroblasts (pMEFs) exhibit resistance towards TNF-induced apoptosis as compared to corresponding wild-type and Jnk1-/- pMEFs. JNK2-deficient pMEFs could be resensitized to TNF via retroviral transduction of any of the four different JNK2 splicing variants. Jnk2-/- pMEFs displayed deficient and delayed effector caspase activation as well as impaired cytosolic cystein cathepsin activity: processes that both were needed for efficient TNF-induced apoptosis in pMEFs. Our work demonstrates that JNK has a central role in the promotion of TNF-induced apoptosis in pMEFs, and that the JNK2 isoform can regulate both mitochondrial and lysosomal death pathways in these cells.Cell Death and Differentiation (2004) 11, 301-313. doi:10.1038/sj.cdd.4401353 Published online 12 December 2003 [ABSTRACT FROM AUTHOR]

In catabolic conditions, such as cancer cachexia, a balance favouring a cytokine environment culminates in muscle destruction. Utilising an in vitro model to mimic muscle wasting, we elucidate here the multifaceted roles that one such cytokine, TNF-α, invokes in the degeneration process. Treatment of C2 skeletal myoblasts with TNF-α not only suppresses morphological and biochemical differentiation, but following an initial wave of proliferation, and of survival (24 h), induces apoptosis. Investigating the mechanisms underlying these diverse actions of TNF-α, we demonstrate that cell replication is dependent on rapid and sustained activation of MAP kinase. Map kinase is not, however, central to the death process, which is associated with a progressive rise in caspase-8 activity, and is accompanied by sustained activation of JNK1 and transient activation of JNK2. Caspase inhibition caused a dose responsive reduction in cell death, while inhibition of the JNKs caused a significant increase in apoptosis. We further report that PI3 kinase is not involved in conferring early protection against TNF-α-induced death. By contrast, inhibition of NF-κB in the presence of TNF-α culminates in increased cell cycle progression, decreased gadd45β expression and significant and precociously increased cell death, when compared with TNF-α alone. Our results begin to characterise the mechanisms underlying the acute mitogenic and anti-apoptotic roles of TNF-α, which appear to be defined by a balance between MAP kinase, Jun kinase (JNK), NF-κB and gadd45β. They establish that inhibition of any one of these molecules, as may occur following caspase activation, could eliminate vital stem cells required for skeletal muscle regeneration during chronic catabolic conditions. J. Cell. Physiol. 198: 237–247, 2004© 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

During their lifetime, cells encounter many life or death situations that challenge their very own existence. Their survival depends on the interplay within a complex yet precisely orchestrated network of proteins. The Rel/NF-?B signaling pathway and the transcription factors that it activates have emerged as critical regulators of the apoptotic response. These proteins are best known for the key roles that they play in normal immune and inflammatory responses, but they are also implicated in the control of cell proliferation, differentiation, apoptosis and oncogenesis. In recent years, there has been remarkable progress in understanding the pathways that activate the Rel/NF-?B factors and their role in the cell's decision to either fight or surrender to apoptotic challenge. Whereas NF-?B is most commonly involved in suppressing apoptosis by transactivating the expression of antiapoptotic genes, it can promote programmed cell death in response to certain death-inducing signals and in certain cell types. This review surveys our current understanding of the role of NF-?B in the apoptotic response and focuses on many developments since this topic was last reviewed in Oncogene 4 years ago. These recent findings shed new light on the activity of NF-?B as a critical regulator of apoptosis in the immune, hepatic, epidermal and nervous systems, on the mechanisms through which it operates and on its role in tissue development, homoeostasis and cancer.Oncogene (2003) 22, 8961-8982. doi:10.1038/sj.onc.1207230 [ABSTRACT FROM AUTHOR]

In addition to its primary role as growth factor, human growth hormone (hGH) can also participate in cell survival, as already documented by its protective effect on human monocytes or human promyelocytic leukaemia U937 cells exposed to a Fas-mediated cell death signal. However, despite similarities in the molecular events following Fas and TNF-alpha receptor engagement, we report that U937 cells, genetically engineered to constitutively produce hGH, were made more sensitive to TNF-alpha-induced apoptosis than parental cells. This was due to overproduction of the antioxidant glutathione, which decreased the nuclear factor (NF)-kappaB activity known to control the expression of survival genes. These findings were confirmed in vivo, in nude mice bearing U937 tumours coinjected with recombinant hGH and the NF-kappaB -inducing anticancer drug daunorubicin, to avoid the in vivo toxicity of TNF-alpha. This study therefore highlights one of the various properties of hGH that may have potential clinical implications. [ABSTRACT FROM AUTHOR]

Ras signaling involves the activation of several downstream pathways that exhibit isoform specificity. In this study, the basal and tumor necrosis factor α (TNFα)-induced activation of NF-κB has been examined in cells overexpressing H-Ras, K-Ras or N-Ras. Cells expressing H-Ras exhibited a basal κB activity that correlated with sustained IκB kinase activation and lower steady-state levels of IκBα in the cytosol. Upon activation with TNFα, the cells expressing the distinct Ras isoforms behaved similarly in terms of binding of nuclear proteins to a κB sequence and induction of a κB-dependent reporter gene. The basal activation of NF-κB in cells expressing H-Ras impaired staurosporine-induced apoptosis in these cells, through a mechanism that was NF-κB-dependent and inhibitable in the presence of z-VAD. Moreover, titration of caspase activation in response to staurosporine showed a significant resistance in cells expressing H-Ras when compared with the void vector or the N-Ras counterparts. These results indicate that the distinct Ras proteins have specific effects on the NF-κB pathway and that this action contributes to protect cells against apoptosis.Oncogene (2003) 22, 477–483. doi:10.1038/sj.onc.1206179 [ABSTRACT FROM AUTHOR]

Examines the role of c-Jun N-terminal protein kinase (JNK) signaling pathway activation in apoptosis. Promotion of tumor necrosis factor-alpha-induced apoptosis; Initiation of optotic process; Nature of death stimulus.

Discusses a study which assessed the role of Glycogen Synthase Kinase-3 in the regulation of Tumor Necrosis Factor-α-induced Necrosis Factor-κ Β activation in hepatocytes. Background on hepatocyte isolation and culture; Detection of apoptosis; Information on immunofluorescent staining.

Examines the survival and cell death signaling by tumor necrosis factor (TNF)-alpha and the role of caspases in turning off nuclear factor-kappaB survival signal. Role of DAP kinase in TNF-induced apoptosis; Molecular basis of the effect of age on TNF-alpha-induced apoptosis in human T cells.