Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.56 (caspase-3)
 35,750 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human gastric carcinoma cell line HSC-39 has been shown to undergo apoptotic cell death in response to treatment with transforming growth factor beta1 (TGF-beta1). To understand better the cell death mechanism in this TGF-beta1-mediated apoptosis, we investigated the effect of the expression of TGF-beta-stimulated clone 22 (TSC-22) on cell death events. TGF-beta1 induced TSC-22 gene expression in HSC-39 cells only when the cells had previously been adapted to the serum-free culture conditions required to undergo TGF-beta1-mediated apoptosis. HSC-39 cells transfected with a TSC-22 expression vector showed a significant decrease in cell viability compared with those transfected with a control vector. The cellular events characteristic of apoptosis, chromatin condensation and DNA fragmentation were observed only in cells transfected with a TSC-22 expression vector. On immunostaining of the transfected cells, almost every cell that expressed TSC-22 tagged with influenza virus haemagglutinin exhibited the morphology of an apoptotic cell. Partial protection from the cell death effect of TGF-beta1 on HSC-39 cells was observed when cells were treated with acetyl-L-aspartyl-L-glutamyl-L-valyl-L-aspart-1-al (Ac-DEVD-CHO, an inhibitor specific for CPP32-type protease). Protection against cell death by the transfection of a TSC-22 expression vector was also offered by Ac-DEVD-CHO addition. These results suggest that TSC-22 elicits the apoptotic cell death of human gastric carcinoma cells through the activation of CPP32-like protease and mediates the TGF-beta1 signalling pathway to apoptosis.
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PMID:Mechanism of apoptotic cell death of human gastric carcinoma cells mediated by transforming growth factor beta. 921 Apr

The inducible nitric oxide synthase (iNOS) gene is expressed by hepatocytes in a number of physiologic and pathophysiologic conditions affecting the liver including septic and hemorrhagic shock. The molecular regulation of iNOS expression is complex and occurs at multiple levels in the gene expression pathway. The cytokines TNF-alpha, IL-1beta, and INF-gamma synergistically activate iNOS expression in the liver, and the human iNOS gene was first cloned from cytokine-stimulated hepatocytes. iNOS expression requires the transcription factor NF-kappaB and is down-regulated by steroids, TGF-beta, the heat shock response, p53, and nitric oxide (NO) itself. In vivo, hepatic iNOS induction is differentially regulated from the typical acute-phase reactants and is not expressed as a mandatory component of the acute phase response. Thus, numerous mechanisms have evolved to regulate iNOS expression during hepatocellular injury. Studies of the effects of NO in the liver demonstrate that induced NO synthesis plays an important role in hepatocyte function and protects the liver during sepsis and ischemia reperfusion. Its cytoprotective role is best exemplified in a rodent model of endotoxemia. Here the addition of the nonspecific NOS inhibitors significantly increased hepatic damage. NO exerts a protective effect through its ability to prevent intravascular thrombosis by inhibiting platelet adhesion and neutralizing toxic oxygen radicals. NO also exerts a protective effects both in vivo and in vitro by blocking TNF-alpha-induced apoptosis and hepatotoxicity, in part by a thiol-dependent inhibition of caspase-3-like protease activity. These studies demonstrate the cytoprotective effects of NO in the liver and suggest hepatic iNOS expression functions as an adaptive response to minimize inflammatory injury. In addition, NO has anti-tumor effects as well as known mutagenic effects, is involved in the systemic vasodilatation of cirrhosis, and has potent antimicrobial properties.
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PMID:Inducible nitric oxide synthase in the liver: regulation and function. 972 29

Induction of apoptosis in Hep3B hepatoma cells by transforming growth factor beta 1 (TGF-beta 1) was accompanied by the activation of interleukin-1-beta-converting-enzyme-like proteases, which have recently been renamed as caspases. The caspase inhibitor ZVAD-FMK, which has a broader specificity for caspase family proteases, blocked TGF-beta 1-induced apoptosis in a concentration-dependent manner. The caspases in this apoptotic process were further characterized by using a more specific caspase inhibitor, DEVD-FMK, for CPP32-like (caspase-3-like) proteases. Our results demonstrated that CPP32-like proteases were activated during apoptosis triggered by TGF-beta 1. Enhancement of CPP32-like activity was clearly detected in TGF-beta 1-treated Hep3B cells. Furthermore, cleavage of poly(ADP-ribose) polymerase, an in vivo substrate for CPP32, in these cells was confirmed by immunoblotting. Thus, we suggest that CPP32-like proteases participate in apoptotic cell death induced by TGF-beta 1.
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PMID:Transforming growth factor beta 1 potently activates CPP32-like proteases in human hepatoma cells. 975 20

In this study, we investigated the involvement of caspases in TGFbeta-induced apoptosis in human B cells. Our results show that TGFbeta-mediated nuclear fragmentation, observed in the Epstein-Barr virus-negative Burkitt's Lymphoma cell line BL41, was abolished in the presence of the tripeptide caspase inhibitor zVAD-fmk or the specific caspase-3 inhibitor DEVD-fmk. Other apoptotic manifestations such as cell shrinkage, surface phosphatidylserine expression and chromatin condensation were strongly inhibited by zVAD-fmk but only partially by DEVD-fmk. This suggests that other caspases in addition to caspase-3 control these apoptotis-associated features. Specific activation of caspase-3 during TGFbeta-induced apoptosis was demonstrated by the DEVD-fmk-sensitive expression of the active p17 subunit of caspase-3 and by in vivo cleavage of PARP. In addition, TGFbeta treatment of BL41 promoted the expression of both dephosphorylated and truncated forms of the retinoblastoma protein. Inhibition of caspase-3 activity abolished both nuclear fragmentation and expression of the truncated retinoblastoma protein, without modifying the G1 cell cycle arrest induced by TGFbeta. Our data thus demonstrate that TGFbeta-induced apoptosis of lymphoma B lymphocytes is dependent on caspase activation and involves caspase-dependent cleavage of the retinoblastoma protein.
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PMID:Role of caspases and possible involvement of retinoblastoma protein during TGFbeta-mediated apoptosis of human B lymphocytes. 1037 29

During inflammatory reactions in the central nervous system (CNS), resident macrophages, the microglia, are exposed to Th1 cell-derived cytokines and pro-apoptotic Fas ligand (FasL). Despite the presence of TNF-alpha and IFN-gamma, both being capable of sensitizing microglia to FasL, apoptosis of microglia is not a hallmark of inflammatory diseases of the CNS. In the present study, TGF-beta is found to counteract the effect of TNF-alpha and IFN-gamma to sensitize microglia to FasL-mediated apoptosis. Resistance to Fas-mediated apoptosis by TGF-beta does not correlate with a down-regulation of Fas expression. As a key inhibitor of Fas-mediated apoptosis, we found expression of the cellular FLICE-inhibitory protein (c-FLIP) to be induced by TGF-beta in resting as well as in activated microglia. Induction of FLIP was found to depend on a mitogen-activated protein kinase kinase (MKK)-dependent pathway as shown by the use of the specific MKK-inhibitor PD98059. The presence of FLIP strongly interfered with FasL-induced activation of caspase-8 and caspase-3 preventing subsequent cell death. The presented data provide the first evidence for a TGF-beta-mediated FLIP in macrophage-like cells and suggest a mode of action for the anti-apoptotic role of TGF-beta in the CNS.
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PMID:TGF-beta induces the expression of the FLICE-inhibitory protein and inhibits Fas-mediated apoptosis of microglia. 1116 11

Although TGF-beta1, a growth inhibitor, is known to also induce apoptosis, the molecular mechanism of this apoptosis is largely undefined. Here, we identify the mechanism of TGF-beta1-induced apoptosis in SNU-16 human gastric cancer cells. Cell cycle and TUNEL analysis showed that, upon TGF-beta1 treatment, cells were initially arrested at the G1 phase and then driven into apoptosis. Of note, caspase-3 was activated in accordance with TGF-beta1-induced G1 arrest. Activated caspase-3 is targeted to cleave p21(cip1), p27(kip1), and Rb, which play important roles in TGF-beta-induced G1 arrest, into inactive fragments. Subsequently, Cdk2 was aberrantly activated due to the cleavage of p21 and p27. We found that the inhibition of Cdk2 activity efficiently blocks TGF-beta1-induced apoptosis, whereas it did not prevent caspase-3 activation or the subsequent cleavage of target proteins. In contrast, the suppression of caspase-3 activity inhibited the cleavage of target proteins, the activation of Cdk2, and the induction of apoptosis. Taken together, our results suggest that activation of caspase-3 by TGF-beta1 may initiate the conversion from G1 cell cycle arrest to apoptosis via the cleavage of p21, p27 and Rb, which in turn causes Cdk2 activation and, most significantly, Cdk2 activation as a downstream effector of caspase is a critical step for the execution of TGF-beta1-induced apoptosis.
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PMID:Caspase-mediated Cdk2 activation is a critical step to execute transforming growth factor-beta1-induced apoptosis in human gastric cancer cells. 1131 70

The mechanism by which transforming growth factor-beta1 (TGF-beta1) induces apoptosis of prostate epithelial cells was studied in the NRP-154 rat prostate epithelial cell line. TGF-beta 1 down-regulates expression of Bcl-xL and poly(ADP-ribosyl)polymerase (PARP), promotes cytochrome c release, up-regulates expression of latent caspase-3, and activates caspases 3 and 9. We tested the role of Bcl-xL in this cascade by stably overexpressing Bcl-xL to prevent loss by TGF-beta 1. Clones overexpressing Bcl-xL are resistant to TGF-beta 1 with respect to induction of apoptosis, cytochrome c release, activation of caspases 9 and 3, and cleavage of PARP; yet they remain sensitive to TGF-beta 1 by cell cycle arrest, induction of both fibronectin and latent caspase-3 expression, and loss of PARP expression. We show that Bcl-xL associates with Apaf-1 in NRP-154 cells; but this association does not inhibit the activation of caspases 9 and 3 by cytochrome c. Together, our data suggest that TGF-beta1 induces apoptosis through loss of Bcl-xL, leading to cytochrome c release and the subsequent activation of caspases 9 and 3. Moreover, our data demonstrate that the antiapoptotic effect of Bcl-xL occurs by inhibition of mitochondrial cytochrome c release and not through antagonizing Apaf-1-dependent processing of caspases 9 and 3.
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PMID:Bcl-xL blocks transforming growth factor-beta 1-induced apoptosis by inhibiting cytochrome c release and not by directly antagonizing Apaf-1-dependent caspase activation in prostate epithelial cells. 1132 89

Most of the morphologic changes that are observed in apoptotic cells are caused by a set of cysteine proteases (caspases) that are activated during this process. In previous works from our group we found that treatment of rat fetal hepatocytes with transforming growth factor beta1 (TGF-beta1) is followed by apoptotic cell death. TGF-beta1 mediates radical oxygen species (ROS) production that precedes bcl-xL down-regulation, loss of mitochondrial transmembrane potential, release of cytochrome c, and activation of caspase-3 (Herrera et al., FASEB J 2001;15:741-751). In this work, we have analyzed how TGF-beta1 activates the caspase cascade and whether or not caspase activation precedes the oxidative stress induced by this factor. Our results show that TGF-beta1 activates at least caspase-3, -8, and -9 in rat fetal hepatocytes, which are not required for ROS production, glutathione depletion, bcl-xL down-regulation, and initial cytochrome c release. However, caspase activation mediates cleavage of Bid and Bcl-xL that could originate an amplification loop on the mitochondrial events. An interesting result is that transmembrane potential disruption occurs later than the initial cytochrome c release and is mostly blocked by the pan-caspase inhibitor Z-VAD.fmk, indicating that the decrease in mitochondrial transmembrane potential (Delta(Psi)m) may be a consequence of caspase activity rather than the mechanism by which TGF-beta induces cytochrome c efflux. Finally, although Z-VAD.fmk completely blocks nucleosomal DNA fragmentation, it only delays cell death, which suggests that activation of the apoptotic program by TGF-beta in fetal hepatocytes inevitably leads to death, with or without caspases.
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PMID:Activation of caspases occurs downstream from radical oxygen species production, Bcl-xL down-regulation, and early cytochrome C release in apoptosis induced by transforming growth factor beta in rat fetal hepatocytes. 1152 41

Primary and secondary forms of focal segmental glomerulosclerosis (FSGS) are characterized by depletion of podocytes and constitute a central manifestation of chronic progressive glomerular diseases. Here we report that podocytes undergo apoptosis at early stages in the course of progressive glomerulosclerosis in TGF-beta1 transgenic mice. Apoptosis is associated with progressive depletion of podocytes and precedes mesangial expansion. Smad7 protein expression is strongly induced specifically in damaged podocytes of transgenic mice and in cultured murine podocytes treated with TGF-beta. TGF-beta1 and Smad7 each induce apoptosis in podocytes, and their coexpression has an additive effect. Activation of p38 MAP kinase and caspase-3 is required for TGF-beta-mediated apoptosis, but not for apoptosis induced by Smad7. Unlike TGF-beta, Smad7 inhibits nuclear translocation and transcriptional activity of the cell survival factor NF-kappaB. Our results suggest a novel functional role for Smad7 as amplifier of TGF-beta-induced apoptosis in podocytes and a new pathomechanism for podocyte depletion in progressive glomerulosclerosis.
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PMID:Apoptosis in podocytes induced by TGF-beta and Smad7. 1156 Sep 50

The 2 most common forms of X-linked adreno-leukodystrophy (ALD) are the juvenile or childhood cerebral form with inflammatory demyelination and the adult adrenomyeloneuropathy (AMN) involving spinal cord tracts without significant inflammation. Modifier genes or environmental factors may contribute to the phenotypic variability. We performed immunohistochemical, an in situ polymerase chain reaction, and TUNEL analyses to identify several viruses, lymphocyte subpopulations, apoptotic cells, and effector molecules, focusing on morphologically normal white matter, dysmyelinative and acute demyelinative lesions. No distinguishing viral antigens were detected. Most lymphocytes were CD8 cytotoxic T cells (CTLs) with the alpha/beta TCR, and they infiltrated morphologically unaffected white matter. Only a few oligodendrocytes were immunoreactive for caspase-3. MHC class II- and TGF-beta-positive microglia were present. CD44, which can mediate MHC-unrestricted target cell death, was seen on many lymphocytes and white matter elements. CD1 molecules, which play major roles in MHC-unrestricted lipid antigen presentation, were noted. Our data indicate that unconventional CD8 CTLs are operative in the early stages of dysmyelination/demyelination and that cytolysis of oligodendrocytes, rather than apoptosis, appears to be the major mode of oligodendrocytic death. The presentation of lipid antigens may be a key pathogenetic element in ALD and AMN-ALD.
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PMID:Potential environmental and host participants in the early white matter lesion of adreno-leukodystrophy: morphologic evidence for CD8 cytotoxic T cells, cytolysis of oligodendrocytes, and CD1-mediated lipid antigen presentation. 1158 21


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