Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular signaling pathways that are involved in protection of vascular smooth muscle cells (VSMC) from apoptosis remain poorly understood. This study examines the effect of activators of cAMP/cGMP signaling on apoptosis in non-transfected VSMC and in VSMC transfected with c-myc (VSMC-MYC) or with its functional analogue, E1A-adenoviral protein (VSMC-E1A). Serum-deprived VSMC-E1A exhibited the highest apoptosis measured as the content of chromatin and low molecular weight DNA fragments, phosphatidylserine content in the outer surface of plasma membrane and caspase-3 activity (ten-, five-, four- and tenfold increase after 6 h of serum withdrawal, respectively). In VSMC-E1A, the addition of an activator of adenylate cyclase, forskolin, abolished chromatin cleavage, DNA laddering, caspase-3 activation and the appearance of morphologically-defined apoptotic cells triggered by 6 h of serum deprivation. In non-transfected VSMC and in VSMC-MYC, 6 h serum deprivation led to approximately six- and threefold activation of chromatin cleavage, respectively, that was also blocked by forskolin. In VSMC-E1A, inhibition of apoptosis was observed with other activators of cAMP signaling (cholera toxin, isoproterenol, adenosine, 8-Br-cAMP), whereas 6 h incubation with modulators of cGMP signaling (8-Br-cGMP, nitroprusside, atrial natriuretic peptide, L-NAME) did not affect the development of apoptotic machinery. The antiapoptotic effect of forskolin was abolished in 24 h of serum deprivation that was accompanied by normalization of intracellular cAMP content and protein kinase A (PKA) activity. Protection of VSMC-E1A from apoptosis by forskolin was blunted by PKA inhibitors (H-89 and KT5720), whereas transfection of cells with PKA catalytic subunit attenuated apoptosis triggered by serum withdrawal. The protection of VSMC-E1A by forskolin from apoptosis was insensitive to modulators of cytoskeleton assembly (cytochalasin B, colchicine). Neither acute (30 min) nor chronic (24 h) exposure of VSMC to forskolin modified basal and serum-induced phosphorylation of the MAP kinase ERK1/2. Thus, our results show that activation of cAMP signaling delays the development of apoptosis in serum-deprived VSMC at a site upstream of caspase-3 via activation of PKA and independently of cAMP-induced reorganization of the cytoskeleton network and the ERK1/2-terminated MAPK signaling cascade.
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PMID:Activation of cAMP signaling transiently inhibits apoptosis in vascular smooth muscle cells in a site upstream of caspase-3. 1045 77

Rod photoreceptors are highly compartmentalized sensory neurons that maintain strict ultrastructural and molecular polarity. Structural subdivisions include the outer segment, inner segment, cell body, and synaptic terminal. The visual pigment rhodopsin is found predominantly in membranes of the rod cell outer segment but becomes mislocalized, appearing throughout the plasma membrane of the cell in many retinal diseases and injuries. Currently, there is no known link between rhodopsin redistribution and rod cell death. We propose that activation of mislocalized rhodopsin kills rod cells by stimulating normally inaccessible signaling pathways. This hypothesis was tested in primary retinal cell cultures, which contain photoreceptors. In rod photoreceptors, opsin immunofluorescence occurred throughout the rod cell plasma membrane. Activation of this mislocalized opsin by photostimulation after formation of isorhodopsin or by incubation with beta-ionone (opsin agonist) killed 19-30% of rod cells. Rod cell death was apoptotic, as indicated by marked chromatin condensation and the requirement for caspase-3 activation. Rod cell death could be induced by forskolin (adenylate cyclase agonist), and conversely, beta-ionone-induced cell death could be blocked by cotreatment with SQ22536 (an adenylate cyclase inhibitor). Pertussis toxin (a G protein inhibitor) also blocked beta-ionone-induced cell death. The data support a mechanism by which activation of mislocalized opsin initiates apoptotic rod cell death through G protein stimulation of adenylate cyclase.
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PMID:Activation of mislocalized opsin kills rod cells: a novel mechanism for rod cell death in retinal disease. 1194 54

Recent reports indicate that cAMP-elevating agents can protect against cell death induced by many stimuli, including tumour necrosis factor-alpha (TNF-alpha). We investigated the ability of cAMP-elevating agents to modulate TNF-alpha-mediated cytotoxicity in L929 cells. Using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) reduction assay and a DNA fragmentation assay as indicators of cell survival, we have shown that forskolin confers partial protection against TNF-alpha-mediated cytotoxicity and inhibits TNF-alpha-induced internucleosomal DNA fragmentation in L929 cells. The protection conferred by forskolin is cAMP-independent since 1,9-dideoxyforskolin (an adenylate cyclase-inactive analog) also protected against TNF-alpha, while both dibutyryl-cAMP and the cAMP-phosphodiesterase inhibitor theophylline were not protective. This is the first example (that we know of) of cAMP-independent cytoprotection by forskolin. We conclude that forskolin acts in a cAMP-independent manner, potentially at a site upstream of caspase-3 activation, to protect against TNF-alpha-mediated cytotoxicity in L929 cells, and that cAMP elevation, in general, does not confer protection against TNF-alpha-induced death in L929 cells. In addition, we observed that Cyclosporin A, a mitochondrial permeability transition (MPT) inhibitor, protected L929 cells against TNF-alpha, underlining the importance of mitochondria in the cytotoxic process induced by TNF-alpha in L929 cells.
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PMID:The adenylate cyclase activator forskolin partially protects L929 cells against tumour necrosis factor-alpha-mediated cytotoxicity via a cAMP-independent mechanism. 1239 72

Prostanoids can suppress vascular smooth muscle cell (VSMC) proliferation, but the mechanism through which this is mediated has not been identified. In this study, we show rat aortic VSMCs to express the EP1, EP2, EP3, EP4, and IP receptors. The EP4 receptor-specific agonist, 11-deoxy-PGE1, induced a time-dependent phosphorylation of protein kinase C and extracellular signal-regulated kinase (ERK) 1/2 in serum-depleted (0.1%) VSMCs, whereas the EP2 receptor agonist, butaprost, was without effect. PGI2 or iloprost at the IP receptor inhibited basal ERK phosphorylation with IC50 values of 10 nmol/L. Iloprost also attenuated the sustained activation of ERK induced by endothelin-1 or basic fibroblast growth factor (bFGF). Endothelin-1 or bFGF significantly increased the number of VSMCs counted 24 hours later compared with basal, and both responses were blocked by the MEK inhibitor, U0126, or iloprost. Under basal conditions, U0126 or iloprost reduced the number of viable cells and increased caspase-3 activity, which could be reversed by coapplication with endothelin-1, bFGF, or the adenylate cyclase inhibitor, SQ22536. Endothelin-1, bFGF, or SQ22536 prevented the depression to below basal levels of ERK phosphorylation induced by iloprost. Forskolin activated caspase-3 and attenuated basal ERK phosphorylation, which were prevented by SQ22536, endothelin-1, or bFGF. These data suggest that iloprost induces apoptosis via a cAMP-mediated suppression of ERK activity. In turn, this apoptotic response can be blocked by a mitogenic stimulus that re-establishes ERK activity back to basal levels, but at the expense of any concomitant proliferative activity. However, ERK stimulation by a selective EP4 receptor agonist, suggests that prostanoids may have diverse and complex roles in VSMC physiology.
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PMID:Prostacyclin induces apoptosis of vascular smooth muscle cells by a cAMP-mediated inhibition of extracellular signal-regulated kinase activity and can counteract the mitogenic activity of endothelin-1 or basic fibroblast growth factor. 1496 6

1. The clinical use of doxorubicin is limited by the development of severe cardiomyopathies linked, at least in part, to an abnormal increase in the rate of apoptotic cell death. Because cell shrinkage is considered to be a crucial step at the onset of apoptosis, the aim of the present study was to investigate whether a brief hypo-osmotic stress, which leads to an increase in cell volume, could interfere with the induction of apoptosis by doxorubicin in adult cardiomyocytes. 2. Cell volume expansion results in intracellular accumulation of cAMP, so we secondarily tested whether the protective effect of hypo-osmotic stress could be related to the cAMP pathway. Accordingly, apoptosis was induced by doxorubicin (1 micromol/L) in cardiomyocytes freshly isolated from New Zealand adult rabbit hearts. 3. Exposure to doxorubicin in an iso-osmotic medium (290 mOsmol/kg H2O) induced a rapid decrease in cell volume, as well as increases in annexin V labelling and caspase-3 activity, two biological markers of apoptosis. These effects of doxorubicin were abolished by 15 min pretreatment with hypo-osmotic stress at 220 mOsmol/kgH2O (HS 220). 4. This cytoprotective effect of HS 220 was still observed when doxorubicin was added to the medium 60 min later, but it was abolished when the pretreatment by HS 220 was associated with the protein kinase A inhibitor KT 5720 (200 nmol/L). 5. Conversely, 15 min pretreatment with either the cAMP analogue 8-bromo-cAMP (0.5 mmol/L) or the adenylate cyclase activator forskolin (10 micromol/L) inhibited apoptosis induced by doxorubicin. 6. In conclusion, these results demonstrate that: (i) apoptosis induced by doxorubicin can be counteracted by a hypo-osmotic stress in adult cardiomyocytes; and (ii) activation of the protein kinase A-dependent pathway plays a major role in the mechanism leading to the cytoprotective effect induced by a hypo-osmotic stress.
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PMID:Hypo-osmotic stress inhibits doxorubicin-induced apoptosis via a protein kinase A-dependent mechanism in cardiomyocytes. 1523 31

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) act as neurotransmitters in numerous biological responses. We previously reported that the replacement of Lys by Arg, and Met by Leu in VIP (IK312532; [Arg15, 20, 21, Leu17]-VIP) resulted in a significant improvement in metabolic stability and biological activity. In the present study, we investigated the effect of VIP and its related peptides including long-acting VIP derivative (IK312532) and PACAP27 on the cytotoxicity of cigarette smoke extract (CSE), a causative factor of chronic obstructive pulmonary disease (COPD), in rat alveolar L2 cells. RT-PCR displayed the dominant expression of mRNA for the VIP-specific VPAC2 receptor in L2 cells, and VIP and the related peptides showed the specific binding activity and potent stimulation of adenylate cyclase. CSE at a concentration of 0.1% or higher induced significant apoptotic death of L2 cells. Interestingly, the addition of neuropeptides at a concentration of 10(-11) M or higher in L2 cells with CSE (0.25%) resulted in significant attenuation of cell death with the deactivation of CSE-evoked caspase-3 activity. IK312532 was much stable against the enzymatic digestion compared to VIP, and the protective effect of IK312532 was 1.6-fold higher than that of VIP. Taken together with our previous report showing that IK312532 has long-acting relaxant activity in the lung, IK312532 may be a potential candidate for drug treatment of asthma and COPD.
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PMID:Long-acting analogue of vasoactive intestinal peptide, [R15, 20, 21, L17]-VIP-GRR (IK312532), protects rat alveolar L2 cells from the cytotoxicity of cigarette smoke. 1551 12

Adenylate cyclase toxin (CyaA) of Bordetella pertussis belongs to the repeat in toxin family of pore-forming toxins, which require posttranslational acylation to lyse eukaryotic cells. CyaA modulates dendritic cell (DC) and macrophage function upon stimulation with LPS. In this study, we examined the roles of acylation and enzymatic activity in the immunomodulatory and lytic effects of CyaA. The adenylate cyclase activity of CyaA was necessary for its modulatory effects on murine innate immune cells. In contrast, acylation was not essential for the immunomodulatory function of CyaA, but was required for maximal caspase-3 activation and cytotoxic activity. The wild-type acylated toxin (A-CyaA) and nonacylated CyaA (NA-CyaA), but not CyaA with an inactive adenylate cyclase domain (iAC-CyaA), enhanced TLR-ligand-induced IL-10 and inhibited IL-12, TNF-alpha, and CCL3 production by macrophages and DC. In addition, both A-CyaA and NA-CyaA, but not iAC-CyaA, enhanced surface expression of CD80 and decreased CpG-stimulated CD40 and ICAM-1 expression on immature DC. Furthermore, both A-CyaA and NA-CyaA promoted the induction of murine IgG1 Abs, Th2, and regulatory T cells against coadministered Ags in vivo, whereas iAC-CyaA had more limited adjuvant activity. In contrast, A-CyaA and iAC-CyaA induced caspase-3 activation and cell death in macrophages, but these effects were considerably reduced or absent with NA-CyaA. Our findings demonstrate that the enzymatic activity plays a critical role in the immunomodulatory effects of CyaA, whereas acylation facilitates the induction of apoptosis and cell lysis, and as such, NA-CyaA has considerable potential as a nontoxic therapeutic molecule with potent anti-inflammatory properties.
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PMID:Bordetella pertussis adenylate cyclase toxin modulates innate and adaptive immune responses: distinct roles for acylation and enzymatic activity in immunomodulation and cell death. 1600 68

Extracellular adenosine reduced viability of RCR-1 rat astrocytoma cells in a dose (0.3-10mM)- and treatment time (24-72h)-dependent manner. In the apoptosis assay using propidium iodide (PI) and annexin V, treatment with adenosine (1mM) for 72h increased the population of PI-negative/annexin V-positive cells, that is related to early apoptosis, and that of PI-positive/annexin V-positive cells, that is related to late apoptosis/secondary necrosis. In addition, nuclei of cells treated with adenosine (1mM) for 72h were reactive to an antibody against single-stranded DNA. Adenosine activated caspase-3, -8 and -9, but mitochondrial membrane potentials were not affected. Adenosine-induced RCR-1 cell death was significantly inhibited by 8-CPT, an antagonist of A(1) adenosine receptors, and forskolin, an adenylate cyclase activator. SQ22536, an adenylate cyclase inhibitor, alternatively, exhibited an effect similar to adenosine. CHA, an agonist of A(1) adenosine receptors, activated caspase-3 and -9, but not caspase-8. Adenosine-induced cytotoxicity of RCR-1 cells was also significantly inhibited by dipyridamole, an inhibitor of adenosine transporter, and AMDA, an inhibitor of adenosine kinase. AICAR, an activator of AMP-activated protein kinase (AMPK), reduced RCR-1 cell viability, but synergistic effect was not obtained with co-treatment with adenosine and AICAR. AICAR activated caspase-3 and -9, but not caspase-8. An additive inhibition was found in the co-presence of 8-CPT and dipyridamole. Extracellular adenosine, thus, appears to activate caspase-9 followed by the effector caspase, caspase-3, at least via two independent pathways linked to A(1) adenosine receptor-mediated adenylate cyclase inhibition and adenosine uptake into cells/conversion to AMP/activation of AMPK, possibly regardless of mitochondrial damage, thereby leading to RCR-1 cell death, dominantly by apoptosis. Moreover, caspase-8 activation could again contribute to adenosine-induced cytotoxicity, although the underlying mechanism is currently unknown. Collectively, the results of the present study may represent a new pathway for caspase activation relevant to diverse adenosine signals in cell death.
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PMID:A(1) adenosine receptor signal and AMPK involving caspase-9/-3 activation are responsible for adenosine-induced RCR-1 astrocytoma cell death. 1646 85

The present study examined the possibility to enhance lung cancer cell cytotoxicity and apoptosis of the anticancer drug cisplatin by exposure with adenylate cyclase (AC) toxin from Bordetella pertussis. A malignant mesothelioma cell line (P31) and a small-cell lung cancer cell line (U1690) were exposed to increasing concentrations of cisplatin and AC toxin, alone or in combination. Cytotoxicity was determined by a fluorescein-based assay and apoptosis by flow cytometry quantification of annexin V binding. Caspase-3, -8, and -9 activities were measured by enzyme activity assays. The cytotoxicity of AC toxin was time and dose dependent with an LD50 value at 72 h of 3 and 7 mg/L for P31 cells and U1690 cells, respectively. Cisplatin showed a similar time- and dose-dependent cytotoxicity, which was increased in the presence of a low toxic concentration (1 mg/L) of AC toxin. Furthermore, cisplatin caused a dose-dependent increase of annexin V binding cells of both cell lines after 24-h incubation, which was also enhanced in combination with AC toxin. AC toxin (1 mg/L) increased cisplatin-induced caspase-3, -8, and -9 activities in U1690 cells. Only minor increases of caspase-8 and -9 were noted for P31 cells. The present results, together with the knowledge that bacterial toxins decrease side effects of traditional cancer treatment, suggest a possibility to use them to enhance the therapeutic effect of cancer chemotherapy with reduced clinical adverse effects.
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PMID:Adenylate cyclase toxin from Bordetella pertussis enhances cisplatin-induced apoptosis to lung cancer cells in vitro. 1655 48

In earlier studies from this laboratory, Xanthomonas campestris pv. glycines was found to exhibit a nutrition stress-related postexponential rapid cell death (RCD). The RCD was exhibited in protein-rich media but not in starch or other minimal media. This RCD in X. campestris pv. glycines was found to display features similar to those of the programmed cell death (PCD) of eukaryotes. Results of the present study showed that the observed RCD in this organism is both positively and negatively regulated by small molecules. The amino acids glycine and l-alanine as well as the D isomers of valine, methionine, and threonine were found to induce the synthesis of an active caspase-3-like protein that was associated with the onset of RCD. Addition of pyruvate and citrate to the culture medium induced both the synthesis of active caspase-3-like protein and RCD. Higher levels of intracellular accumulation of pyruvate and citrate were also observed under conditions favoring RCD. On the other hand, dextrin and maltose, the hydrolytic products of starch, inhibited the synthesis of the caspase-3-like protein. Addition of glucose and cyclic AMP (cAMP) to the RCD-favoring medium prevented RCD. Glucose, cAMP, caffeine (a known inhibitor of a phosphodiesterase that breaks down cAMP), and forskolin (from the herb Coleus forskholii, known to activate the enzyme adenylate cyclase that forms cAMP) inhibited the caspase enzyme activity in vivo and consequently the RCD process. The addition of glucose and other inhibitors of RCD enhanced intracellular cAMP accumulation. This is the first report demonstrating the involvement of small molecules in the regulation of nutrition stress-related stationary-phase rapid cell death in X. campestris pv. glycines, which is programmed.
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PMID:Molecules involved in the modulation of rapid cell death in Xanthomonas. 1685 30


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