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

By using a mouse NIH3T3 derivate designed 7-4 harboring the inducible Ha-ras oncogene, we demonstrated the close relationship between Ha-ras expression level and sensitization of 5-flurouracil (5-FU)-treated cells. Further studies revealed that the cells susceptible to 5-FU treatment died of apoptosis, which was demonstrated by caspase-3 activation, loss of mitochondria membrane potential (MMP), and DNA fragmentation. The 7-4 cells coexpressing dominant negative Ras (Ras(Asn17)), dominant negative Raf-1 (Raf-1(CB4)), Bcl-2, or active form of phosphatidylinositol 3-kinase (PI3K) became resistant to 5-FU, and apoptosis was prevented. In contrast, the cells coexpressing dominant negative Rac 1 (Rac1(Asn17)) or dominant negative Rho A (RhoA(Asn19)) showed no change of sensitivity to 5-FU. These results indicate that Ras, Bcl-2, as well as Raf-1 and PI3K pathways play pivotal roles in 5-FU-induced apoptosis under Ha-ras-overexpressed condition. Aberrant levels of cyclin E and p21(Cip/WAF-1) expression as well as Cdc 2 phosphorylation at Tyrosine 15 suggest that perturbation of G1/S and G2/M transitions in cell cycle might be responsible for 5-FU triggered apoptosis. Sensitization of Ha-ras-related cells to 5-FU was also demonstrated in human bladder cancer cells. Through understanding the mechanism of 5-FU induced apoptosis in tumor cells, a new direction toward the treatment of Ha-ras oncogene-related cancers with 5-FU at more optimal dosages is possible and combinational therapy with other drugs that suppress PI3K and Bcl-2 activities can also be considered.
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PMID:Ha-ras overexpression mediated cell apoptosis in the presence of 5-fluorouracil. 1291 31

The embryonic chicken corneal epithelium is a unique tissue that has been used as an in vitro epithelial sheet organ culture model for over 30 years (Hay and Revel [1969] Fine structure of the developing Avian cornea. Basel, Switzerland: S. Karger A.G.). This tissue was used to establish that epithelial cells could produce extracellular matrix (ECM) proteins such as collagen and proteoglycans (Dodson and Hay [1971] Exp Cell Res 65:215-220; Meier and Hay [1973] Dev Biol 35:318-331; Linsenmayer et al. [1977] Proc Natl Acad Sci U S A 74:39-43; Hendrix et al. [1982] Invest Ophthalmol Vis Sci 22:359-375). This historic model was also used to establish that ECM proteins could stimulate actin reorganization and increase collagen synthesis (Sugrue and Hay [1981] J Cell Biol 91:45-54; Sugrue and Hay [1982] Dev Biol 92:97-106; Sugrue and Hay [1986] J Cell Biol 102:1907-1916). Our laboratory has used the model to establish the signal transduction pathways involved in ECM-stimulated actin reorganization (Svoboda et al. [1999] Anat Rec 254:348-359; Chu et al. [2000] Invest Ophthalmol Vis Sci 41:3374-3382; Reenstra et al. [2002] Invest Ophthalmol Vis Sci 43:3181-3189). The goal of the current study was to investigate the role of ECM in epithelial cell survival and the role of Rho-associated kinase (p160 ROCK, ROCK-1, ROCK-2, referred to as ROCK), in ECM and lysophosphatidic acid (LPA) -mediated actin reorganization. Whole sheets of avian embryonic corneal epithelium were cultured in the presence of the ROCK inhibitor, Y27632 at 0, 0.03, 0.3, 3, or 10 microM before stimulating the cells with either collagen (COL) or LPA. Apoptosis was assessed by Caspase-3 activity assays and visualized with annexin V binding. The ROCK inhibitor blocked actin cortical mat reformation and disrupted the basal cell lateral membranes in a dose-dependent manner and increased the apoptosis marker annexin V. In addition, an in vitro caspase-3 activity assay was used to determine that caspase-3 activity was higher in epithelia treated with 10 microM Y-27632 than in those isolated without the basal lamina or epithelia stimulated with fibronectin, COL, or LPA. In conclusion, ECM molecules decreased apoptosis markers and inhibiting the ROCK pathway blocked ECM stimulated actin cortical mat reformation and increased apoptosis in embryonic corneal epithelial cells.
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PMID:ROCK inhibitor (Y27632) increases apoptosis and disrupts the actin cortical mat in embryonic avian corneal epithelium. 1499 13

Dynamics of alterations of cell surface topography during TNF-induced apoptosis of HeLa cells was examined by phase-contrast videomicroscopy and immunomorphological analysis. The final stage of apoptosis accompanied by cell rounding and general blebbing of the cell surface became after 4-6 h of incubation but much earlier, after 1.5-3 h, essentially flattened lamellipodia at the active edges transformed into the small blebs that were continuously extended and retracted during the next 1-2 h. This phenomenon was called "marginal blebbing". It took place before the cytochrome c release from mitochondria to cytosol. Marginal blebbing was inhibited by drugs that depolymerized actin microfilaments (cytochalasin, latrunculin) or decreased Rho-kinase-dependent contractility of actin-myosin cortex (H7, HA-1077, Y27632). A pancaspase inhibitor, zVAD-fmk, completely prevented marginal and general blebbing, and TNF-induced apoptosis. DEVD-fmk, a specific inhibitor of caspase-3, inhibited both marginal and general blebbing but not cell rounding and death. Thus, marginal blebbing is an early microfilament-dependent apoptotic event. It is suggested that it is initiated by minimal activation of caspase-3 and the following local Rho-kinase-dependent stimulation of actin-myosin cortex contractility. Localization of marginal blebs at the active edge may be associated with special organization of cortex in that zone.
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PMID:Marginal blebbing during the early stages of TNF-induced apoptosis indicates alteration in actomyosin contractility. 1522 24

Transforming growth factor-beta1 (TGF-beta1) is a cytokine critically involved in acute lung injury and endothelial cell (EC) barrier dysfunction. We have studied TGF-beta1-mediated signaling pathways and examined a role of microtubule (MT) dynamics in TGF-beta1-induced actin cytoskeletal remodeling and EC barrier dysfunction. TGF-beta1 (0.1-50 ng/ml) induced dose-dependent decrease in transendothelial electrical resistance (TER) in bovine pulmonary ECs, which was linked to increased actin stress fiber formation, myosin light chain (MLC) phosphorylation, EC retraction, and gap formation. Inhibitor of TGF-beta1 receptor kinase RI (5 microM) abolished TGF-beta1-induced TER decline, whereas inhibitor of caspase-3 zVAD (10 microM) was without effect. TGF-beta1-induced EC barrier dysfunction was linked to partial dissolution of peripheral MT meshwork and decreased levels of stable (acetylated) MT pool, whereas MT stabilization by taxol (5 microM) attenuated TGF-beta1-induced barrier dysfunction and actin remodeling. TGF-beta1 induced sustained activation of small GTPase Rho and its effector Rho-kinase; phosphorylation of myosin binding subunit of myosin specific phosphatase; MLC phosphorylation; EC contraction; and gap formation, which was abolished by inhibition of Rho and Rho-kinase, and by MT stabilization with taxol. Finally, elevation of intracellular cAMP induced by forskolin (50 microM) attenuated TGF-beta1-induced barrier dysfunction, MLC phosphorylation, and protected the MT peripheral network. These results suggest a novel role for MT dynamics in the TGF-beta1-mediated Rho regulation, EC barrier dysfunction, and actin remodeling.
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PMID:Involvement of microtubules and Rho pathway in TGF-beta1-induced lung vascular barrier dysfunction. 1582 24

The folate analogue BGC9331 is a new thymidylate synthase (TS) inhibitor showing a broad spectrum of cyto-toxic activity against several human solid tumors, including colorectal cancer. In this study, we investigated the anticancer activity of BGC9331 either alone or combined with 5-fluorouracil (5-FU), MTA (multi-target antifolate), oxali-platin and SN-38, the active metabolite of the topoisomerase I inhibitor CPT-11. The antiproliferative activity of each drug and BGC9331-based combinations was investigated in the HT-29 human colorectal cancer cell line and its HT-29/5-FU counterparts selected for resistance to 5-FU. BGC9331 combined with MTA or SN-38 induced synergistic responses in HT-29 cells. Treatment of HT-29 cells with either BGC9331 or SN-38 increased caspase-3 activity and the percentage of apoptotic cells from 3 to 13%. Both drugs also augmented the proteolytic cleavage of the Rho-kinase ROCK-1 that was attenuated by the caspase-3 pathway inhibitor z-DEVD-fmk. BGC9331 combined with SN-38 further increased the percentage of apoptotic cells to 25%, and inhibited cell cycle progression and cell proliferation by 65%. This was accompanied by proteolytic activation of ROCK-1, through both caspase-3-dependent and -independent mechanisms, as shown in caspase-3-deficient MCF-7 breast cancer cells. These encouraging results warrant further preclinical investigations and clinical trials on the use of BGC9331 combined with SN-38/CPT-11 in treatment of patients with advanced colorectal or gastric cancers.
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PMID:Increased anticancer activity of the thymidylate synthase inhibitor BGC9331 combined with the topoisomerase I inhibitor SN-38 in human colorectal and breast cancer cells: induction of apoptosis and ROCK cleavage through caspase-3-dependent and -independent mechanisms. 1601 Apr 39

Apoptosis of pancreatic beta cells is implicated in the onset of type 1 and type 2 diabetes. Consequently, strategies aimed at increasing the resistance of beta cells toward apoptosis could be beneficial in the treatment of diabetes. RasGAP, a regulator of Ras and Rho GTPases, is an atypical caspase substrate, since it inhibits, rather than favors, apoptosis when it is partially cleaved by caspase-3 at position 455. The antiapoptotic signal generated by the partial processing of RasGAP is mediated by the N-terminal fragment (fragment N) in a Ras-phosphatidylinositol 3-kinase-Akt-dependent, but NF-kappaB-independent, manner. Further cleavage of fragment N at position 157 abrogates its antiapoptotic properties. Here we demonstrate that an uncleavable form of fragment N activates Akt, represses NF-kappaB activity, and protects the conditionally immortalized pancreatic insulinoma betaTC-tet cell line against various insults, including exposure to genotoxins, trophic support withdrawal, and incubation with inflammatory cytokines. Fragment N also induced Akt activity and protection against cytokine-induced apoptosis in primary pancreatic islet cells. Fragment N did not alter insulin cell content and insulin secretion in response to glucose. These data indicate that fragment N protects beta cells without affecting their function. The pathways regulated by fragment N are therefore promising targets for antidiabetogenic therapy.
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PMID:Expression of an uncleavable N-terminal RasGAP fragment in insulin-secreting cells increases their resistance toward apoptotic stimuli without affecting their glucose-induced insulin secretion. 1604 10

Human plasma membrane-associated sialidase (NEU3), specifically hydrolyzing gangliosides, plays crucial roles in the regulation of cell surface functions. Here we demonstrate that NEU3 mRNA level are increased in renal cell carcinomas (RCCs) compared with adjacent non-tumor tissues, significantly correlating with elevation of interleukin-6 (IL-6), a pleiotropic cytokine that has been implicated in immune responses and pathogenesis of several cancers, including RCCs. In human RCC ACHN cells, IL-6 treatment enhanced NEU3 promoter luciferase activity 2.5-fold and the endogenous sialidase activity significantly. NEU3 transfection or IL-6 treatment resulted in both suppression of apoptosis and promotion of cell motility, and the combination had synergistic effects. NEU3 scarcely affected MAPK- or IL-6-induced STAT3 activation but promoted the phosphatidylinositol 3-kinase (PI3K)/Akt cascade in both IL-6-dependent and -independent ways. Consistent with these data, NEU3 markedly inhibited staurosporine-induced caspase-3 activity and enhanced IL-6-dependent inhibition, which was abolished by LY294002, a PI3K inhibitor. Furthermore, IL-6 promoted Rho activation, and the effect was potentiated by NEU3, leading to increased cell motility that was again affected by LY294002. NEU3 silencing by siRNA resulted in the opposite: decreased Akt phosphorylation and inhibition of Rho activation. Glycolipid analysis showed a decrease in ganglioside GM3 and increase in lactosylceramide after NEU3 transfection, with these lipids apparently affecting cell apoptosis and motility. The results indicate that NEU3 activated by IL-6 exerts IL-6-mediated signaling, largely via the PI3K/Akt cascade, in a positive feedback manner and contributes to expression of a malignant phenotype in RCCs. NEU3 thus may be a useful target for RCC diagnosis and therapy.
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PMID:Plasma membrane-associated sialidase is up-regulated in renal cell carcinoma and promotes interleukin-6-induced apoptosis suppression and cell motility. 1642 83

Severe pulmonary hypertension (SPH) is characterized by precapillary arteriolar lumen obliteration, dramatic right ventricular hypertrophy, and pericardial effusion. Our recently published rat model of SPH recapitulates major components of the human disease. We used this model to develop new treatment strategies for SPH. SPH in rats was induced using VEGF receptor blockade in combination with chronic hypoxia. A large variety of drugs used in this study, including anticancer drugs (cyclophosphamide and paclitaxel), the angiotensin-converting enzyme inhibitor lisinopril, the antiangiogenic agent thalidomide, and the peroxisome proliferator-actived receptor-gamma agonist PGJ2, failed to decrease mean pulmonary artery pressure (PAP) or right ventricular hypertrophy. In contrast, treatment of rats with established SPH with simvastatin markedly reduced mean PAP and right ventricular hypertrophy, and this reduction was associated with caspase-3 activation and pulmonary microvascular endothelial cell apoptosis. Simvastatin partially restored caveolin-1, caveolin-2, and phospho-caveolin expression in vessel walls. In rat primary pulmonary microvascular endothelial cells, simvastatin induced caspase 3 activation and Rac 1 expression while suppressing Rho A and attenuated levels of Akt and ERK phosphorylation. We conclude that simvastatin is effective in inducing apoptosis in hyperproliferative pulmonary vascular lesions and could be considered as a potential drug for treatment of human SPH.
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PMID:Simvastatin causes endothelial cell apoptosis and attenuates severe pulmonary hypertension. 1669 53

Activation of Akt/protein kinase B has been recently reported to play an important role in ischemic tolerance. We here demonstrate that the decreased protein expression and phosphorylation of phosphatase and tensin homolog deleted from chromosome 10 (PTEN) underlie the increased Akt-Ser-473 phosphorylation in the hippocampal CA1 subfield in ischemic preconditioning (IPC). Co-immunoprecipitation analysis reveals that Akt physically interacts with Rac1, a small Rho family GTPase required for mixed lineage kinase 3 (MLK3) autophosphorylation, and both this interaction and Rac1-Ser-71 phosphorylation induced by Akt are promoted in preconditioned rats. In addition, we show that Akt activation results in the disassembly of the plenty of SH3s (POSH)-MLK3-Rac1 signaling complex and down-regulation of the activation of MLK3/c-Jun N-terminal kinase (JNK) pathway. Akt activation results in decreased serine phosphorylation of 14-3-3, a cytoplasmic anchor of Bax, and prevents ischemia-induced mitochondrial translocation of Bax, release of cytochrome c, and activation of caspase-3. The expression of Fas ligand is also decreased in the CA1 region. Akt activation protects against apoptotic neuronal death as shown in TUNEL staining following IPC. Intracerebral infusion of LY294002 before IPC reverses the increase in Akt phosphorylation and the decrease in JNK signaling activation, as well as the neuroprotective action of IPC. Our results suggest that activation of pro-apoptotic MLK3/JNK3 cascade can be suppressed through activating anti-apoptotic phosphoinositide 3-kinase/Akt pathway induced by a sublethal ischemic insult, which provides a functional link between Akt and the JNK family of stress-activated kinases in ischemic tolerance.
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PMID:Ischemic preconditioning negatively regulates plenty of SH3s-mixed lineage kinase 3-Rac1 complex and c-Jun N-terminal kinase 3 signaling via activation of Akt. 1697 99

Rho-associated coiled-coil protein kinase 1 (ROCK-1) is a direct cleavage substrate of activated caspase-3, which is associated with heart failure. In the course of human heart failure, we found marked cleavage of ROCK-1 resulting in a 130-kDa subspecies, which was absent in normal hearts and in an equivalent cohort of patients with left ventricular assist devices. Murine cardiomyocytes treated with doxorubicin led to enhanced ROCK-1 cleavage and apoptosis, all of which was blocked by a caspase-3 inhibitor. In addition, a bitransgenic mouse model of severe cardiomyopathy, which overexpresses Gq protein and hematopoietic progenitor kinase-/germinal center kinase-like kinase, revealed the robust accumulation of the 130-kDa ROCK-1 cleaved fragment. This constitutively active ROCK-1 subspecies, when expressed in cardiomyocytes, led to caspase-3 activation, indicating a positive feed-forward regulatory loop. ROCK-1-dependent caspase-3 activation was coupled with the activation of PTEN and the subsequent inhibition of protein kinase B (Akt) activity, all of which was attenuated by siRNA directed against ROCK-1 expression. Similarly, ROCK-1-null mice (Rock-1(-/-)) showed a marked reduction in myocyte apoptosis associated with pressure overload. These data suggest an obligatory role for ROCK-1 cleavage in promoting apoptotic signals in myocardial hypertrophy and/or failure.
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PMID:Activation of Rho-associated coiled-coil protein kinase 1 (ROCK-1) by caspase-3 cleavage plays an essential role in cardiac myocyte apoptosis. 1698 89


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