Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in a variety of human malignancies, including hepatocellular carcinoma (HCC), but so far it is unknown whether COX-2 contributes to the malignant growth and whether inhibition of COX-2 function modifies the malignant potential of liver tumors. COX-1 and COX-2 expression was determined in 4 liver tumor cell lines (Hep 3B, HuH-7, Hep G2, Sk-hep1) by Northern hybridization and Western immunoblot. The functional effects of the nonselective inhibitor sulindac sulfide and the COX-2 selective inhibitors SC-58635 and meloxicam were examined by 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide (MTT)-assays and BrdU uptake, morphology, and TUNEL analysis of apoptosis. Apoptosis regulating proteins were analyzed by Western immunoblot. COX-1 and COX-2 expression was demonstrable in all tested liver tumor cell lines. Sulindac sulfide (50 to 400 micromol/L), SC-58635 (6,25 to 400 micromol/L), and meloxicam (6.25 to 400 micromol/L) led to a significant time- and dose-dependent reduction of cell numbers of up to 80% (P <.05). At equimolar concentrations the effect was more pronounced when COX-2 was selectively blocked. COX-2 inhibition induced apoptosis and reduced tumor cell proliferation. Apoptosis after COX-2 inhibition with SC-58635 (50 micromol/L) was independent of BCL-2, BAX, and the phosphorylation status of AKT/PKB and BAD, but correlated with activation of caspase-9, caspase-3, and caspase-6. In conclusion, selective inhibition of COX-2 leads to a marked growth inhibition of human liver tumor cells, based on the induction of apoptosis and inhibition of proliferation and, thus, may offer therapeutic and preventive potential in human hepatocarcinogenesis.
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PMID:Proapoptotic and antiproliferative potential of selective cyclooxygenase-2 inhibitors in human liver tumor cells. 1229 35

Recently we demonstrated the induction of apoptosis by the addition of recombinant lipocalin-type prostaglandin D(2) synthase (L-PGDS) to the culture medium of LLC-PK(1) cells. Because protein kinase C (PKC) has been shown to be involved in the apoptotic process of various cell types, we examined the potential role of L-PGDS in phorbol 12-myristate 13-acetate (PMA)-induced apoptosis. We report here the enzymatic activation and phosphorylation of L-PGDS in response to phorbol ester in cell culture and the direct phosphorylation of recombinant L-PGDS by PKC in vitro. Treatment of cells with PMA or L-PGDS decreased phosphatidylinositol 3-kinase (PI3-K) activity and concomitantly inhibited protein kinase B (PKB/Akt) phosphorylation, which led to the hypophosphorylation and activation of Bad. In addition, hypophosphorylation of retinoblastoma protein was also observed in response to L-PGDS-induced apoptosis. Cellular depletion of L-PGDS levels by using an antisense RNA strategy prevented PI3-K inactivation by phorbol ester and inhibited caspase-3 activation and apoptosis. We conclude that phorbol ester-induced apoptosis is mediated by L-PGDS phosphorylation and activation by PKC and is accompanied by inhibition of the PI3-K/PKB anti-apoptotic signaling pathways.
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PMID:Elevated L-PGDS activity contributes to PMA-induced apoptosis concomitant with downregulation of PI3-K. 1238 64

Apo2 ligand (Apo2L/TRAIL) is a member of the tumor necrosis factor (TNF) cytokine family. Apo2L/TRAIL can selectively induce programmed cell death in transformed cells, although its wide tissue distribution suggests potential physiological roles. We have investigated the expression, in human osteoblast-like cells (NHBC), of Apo2L/TRAIL and the known Apo2L/TRAIL death receptors, DR4 and DR5, and the Apo2L/TRAIL decoy receptors, DcR-1, DcR-2, and osteoprotegerin (OPG). NHBC expressed abundant mRNA corresponding to each of these molecular species. Immunofluorescence staining demonstrated that Apo2L/TRAIL protein was abundant within the cytoplasm of NHBC and OPG was strongly expressed at the cell surface. DR5 and DcR-2 were present in the cell membrane and cytoplasm and DcR-1 was confined to the nucleus. DR4 staining was weak. Neither Apo2L/TRAIL alone, nor in combination with chemotherapeutic agents of clinical relevance to treatment of osteogenic sarcoma, induced cell death in NHBC, as assessed morphologically and by activation of caspase-3. In contrast, the human osteogenic sarcoma cell lines, BTK-143 and G-292, were sensitive to exogenous Apo2L/TRAIL alone, and to the combined effect of Apo2L/TRAIL/cisplatin and Apo2L/TRAIL/doxorubicin treatments, respectively. In NHBC, we observed strong associations between the levels of mRNA corresponding to the pro-apoptotic molecules, Apo2L/TRAIL, DR4, and DR5, and those corresponding to pro-survival molecules, DcR-1, DcR-2, OPG, and FLIP, suggesting that the balance between pro-survival and pro-apoptotic molecules is a mechanism by which NHBC can resist Apo2L/TRAIL-mediated apoptosis. In contrast, osteogenic sarcoma cells had low or absent levels of DcR-1 and DcR-2. These results provide a foundation to explore the role of Apo2L/TRAIL in osteoblast physiology. In addition, they predict that therapeutic use of recombinant Apo2L/TRAIL, in combination with chemotherapeutic agents to treat skeletal malignancies, would have limited toxic effects on normal osteoblastic cells.
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PMID:Human osteoblasts are resistant to Apo2L/TRAIL-mediated apoptosis. 1239 39

The hepatic stellate cell (HSC), the pericyte of the liver sinusoids belongs to the mesenchymal cells of the liver. Damaging noxae induce a transformation from the quiescent (vitamin A-storing cell) to the activated (connective tissue-producing cell) state. The balance between proapoptotic and surviving factors decides about the fate of the activated HSC. Interferon-alpha (IFN-alpha) has been shown to elicit antiproliferative and/or antifibrogenic effects in various cell types of mesenchymal origin. We therefore investigated the effect of IFN-alpha on primary cultured rat HSC in their quiescent (day 2) and activated state (day 7). IFN-alpha significantly inhibited spontaneous apoptosis in activated HSC in vitro and simultaneously inhibited cell cycle progression by inducing a G1 arrest. The effect of IFN-a is not accompanied by a modulation of CD95, CD95L, p53, p21(WAF1), p27, bcl-2, bcl-xL, bax, NFkappaB, or IkappaB gene expression. Surprisingly, the IFN-alpha effect could be abolished completely by blocking JAK2 activity or JAK2 translation. The downregulating effect of IFN-alpha on the activity of caspase-8 and caspase-3 could also be neutralized using tyrphostin AG490 or JAK-2 antisense. Taken together IFN-alpha inhibits apoptosis of activated HSC by activation of JAK2 which inhibits the caspase-8 apoptosis pathway.
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PMID:Antiapoptotic effect of interferon-alpha on hepatic stellate cells (HSC): a novel pathway of IFN-alpha signal transduction via Janus kinase 2 (JAK2) and caspase-8. 1260 46

We have investigated the mechanism of IL-7-mediated inhibition of dexamethasone-induced apoptosis in T cells. Broad-spectrum caspase inhibitors block dexamethasone-triggered nuclear fragmentation, but not the loss of mitochondrial transmembrane potential or membrane integrity in CD3(+) mature T cells isolated from adult mouse spleens. IL-7 blocked dexamethasone-induced apoptosis and the processing of caspase-3 and caspase-7. IL-7 also blocked dexamethasone-triggered dephosphorylation of the serine-threonine kinase Akt/PKB and its target, the Ser(136) residue in Bad. The loss of anti-apoptotic proteins Bcl-x(L) and inhibitor of apoptosis protein-2 (IAP-2) was also blocked by IL-7. The protective effect was attenuated by pharmacological inhibitors of phosphatidylinositol-3 kinase (PI3K) with one exception: inhibition of PI3K did not abrogate Bcl-x(L) expression in the presence of IL-7. The anti-apoptotic role of Akt suggested by these experiments was tested by overexpression of constitutively active Akt, which blocked dexamethasone-induced apoptosis and elevated IAP-2 but not Bcl-x(L) levels in a mature T cell line. Thus, IL-7 regulates IAP-2 expression and inhibits dexamethasone-induced apoptosis by activating Akt via PI3K-dependent signaling, but regulates Bcl-x(L)expression via a PI3K-independent pathway in mature T cells.
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PMID:IL-7 inhibits dexamethasone-induced apoptosis via Akt/PKB in mature, peripheral T cells. 1267 57

K562 cells express the fusion protein BCR-ABL and have been shown to be relatively more resistant to apoptosis induction by chemotherapeutic agents. We show that Actinomycin D (Act D) induces time- and dose-dependent apoptosis in K562 cells. Act D causes early activation of caspase-3 followed by inhibition of the expression of the anti-apoptotic proteins BCR-ABL and Bcl-xl. Act D-induced apoptosis is associated with cytoplasmic translocation and cleavage of the multifunctional nuclear protein RNA helicase A (RHA). RHA has roles in transcription and RNA metabolism and has been shown to be cleaved during Fas mediated apoptosis. These results suggest that Act D causes caspase-3 activation and apoptosis in BCR-ABL positive K562 cells and that RHA cytoplasmic translocation and cleavage occur in chemotherapy-induced apoptosis.
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PMID:The actinomycin D-induced apoptosis in BCR-ABL-positive K562 cells is associated with cytoplasmic translocation and cleavage of RNA helicase A. 1268 Feb 54

We previously showed (Gastroenterology 123: 206-216, 2002) that lysophosphatidic acid (LPA) protects and rescues rat intestinal epithelial cells (IEC-6) from apoptosis. Here, we provide evidence for the LPA-elicited inhibition of the mitochondrial apoptotic pathway leading to attenuation of caspase-3 activation. Pretreatment of IEC-6 cells with LPA inhibited campothecin-induced caspase-9 and caspase-3 activation and DNA fragmentation. A caspase-9 inhibitor peptide mimicked the LPA-elicited antiapoptotic activity. LPA elicited ERK1/ERK2 and PKB/Akt phosphorylation. The LPA-elicited antiapoptotic activity and inhibition of caspase-9 activity were abrogated by pertussis toxin, PD 98059, wortmannin, and LY 294002. LPA reduced cytochrome c release from mitochondria and prevented activation of caspase-9. LPA prevented translocation of Bax from cytosol to mitochondria and increased the expression of the antiapoptotic Bcl-2 mRNA and protein. LPA had no effect on Bcl-xl, Bad, and Bak mRNA or protein expression. These data indicate that LPA protects IEC-6 cells from camptothecin-induced apoptosis through G(i)-coupled inhibition of caspase-3 activation mediated by the attenuation of caspase-9 activation due to diminished cytochrome c release, involving upregulation of Bcl-2 protein expression and prevention of Bax translocation.
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PMID:LPA protects intestinal epithelial cells from apoptosis by inhibiting the mitochondrial pathway. 1268 13

Despite increasing evidence on the formation of 1H NMR-detectable mobile lipid (ML) domains in cells induced to programmed cell death by continuous exposure to anticancer drugs, the time course of ML generation during the apoptotic cascade has not yet been fully elucidated. The present study shows that ML formation occurs at two different stages of apoptosis induced in human erythroleukemia K562 cells by a brief (3 hr) exposure to paclitaxel (Taxol), an antitumour drug with a stabilising effect on microtubules, or to paclitaxel plus tyrphostin AG957, a selective inhibitor of the p210(BCR-ABL) tyrosine kinase activity. A first wave of ML generation was in fact detected in paclitaxel-treated cells at the onset of the effector phase (8-24hr after exposure to the drug), plateaued at 24-48 hr and was eventually followed by further ML accumulation during the degradative phase (48-72 hr). Addition of AG957 to paclitaxel shifted to the 3-8 hr interval in both the early ML production and the onset of apoptotic events, such as chromatin condensation, phosphatidylserine externalization, cytochrome c release and caspase-3 activation. A significant loss of mitochondrial membrane potential was almost concomitant with the second wave of ML accumulation, associated in both cell systems with the phase of terminal cell degeneration, likely connected to non-regulated degradation of cell lipid components.
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PMID:Two-step formation of 1H NMR visible mobile lipids during apoptosis of paclitaxel-treated K562 cells. 1269 68

Cathepsin G is a neutrophil-derived serine protease that contributes to tissue damage at sites of inflammation. The actions of cathepsin G are reported to be mediated by protease-activated receptor (PAR)-4 (a thrombin receptor) in human platelets. This study provides the first evidence that cathepsin G promotes inositol 1,4,5-trisphosphate accumulation, activates ERK, p38 MAPK, and AKT, and decreases contractile function in cardiomyocytes. Because some cathepsin G responses mimic cardiomyocyte activation by thrombin, a role for PARs was considered. Cathepsin G markedly activates phospholipase C and p38 MAPK in cardiomyocytes from PAR-1-/- mice, but it fails to activate phospholipase C, ERK, p38 MAPK, or AKT in PAR-1- or PAR-4-expressing PAR-1-/- fibroblasts (which display robust responses to thrombin). These results argue that PAR-1 does not mediate the actions of cathepsin G in cardiomyocytes, and neither PAR-1 nor PAR-4 mediates the actions of cathepsin G in fibroblasts. Of note, prolonged incubation of cardiomyocytes with cathepsin G results in the activation of caspase-3, cleavage of FAK and AKT, sarcomeric disassembly, cell rounding, cell detachment from underlying matrix, and morphologic features of apoptosis. Inhibition of Src family kinases or caspases (with PP1 or benzyloxycarbonyl-VAD-fluoromethyl ketone, respectively) delays FAK and AKT cleavage and cardiomyocyte detachment from substrate. Collectively, these studies describe novel cardiac actions of cathepsin G that do not require PARs and are predicted to assume functional importance at sites of interstitial inflammation in the heart.
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PMID:Neutrophil cathepsin G promotes detachment-induced cardiomyocyte apoptosis via a protease-activated receptor-independent mechanism. 1270 81

Using differential display, we isolated DDC-4, a secreted frizzled-related protein (sFRP), which is induced in the physiological apoptosis of hormonally regulated, reproductive tissues such as mammary gland, prostate, corpus luteum and uterus. The role of this gene in apoptosis was studied in animals overexpressing ectopic DDC-4/sFRP-4. Transgenic mice bearing the DDC-4/sFRP-4 cDNA under the control of the MMTV-LTR promoter showed lactational insufficiency and many apoptotic cells in the alveoli between day 19 of pregnancy and day 4 of lactation as demonstrated by TUNEL reaction and the presence of activated caspase-3. We performed a PKB/Akt kinase assay and studied several of its substrates using phosphorylation-specific antibodies to show reduced phosphorylation in PKB/Akt itself, as well as in glycogen synthetase kinase-3beta (GSK-3beta), BAD, and Forkhead. Taken together, our results show a role for DDC-4/sFRP-4 in abrogating an epithelial cell survival pathway at the onset of mammary gland involution.
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PMID:Role of DDC-4/sFRP-4, a secreted frizzled-related protein, at the onset of apoptosis in mammary involution. 1272 51


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