Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytotoxic effect of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is limited in some cancer cells, including A549 lung adenocarcinoma cells. However, treatment with TRAIL in combination with subtoxic concentrations of sulforaphane (SFN) sensitizes TRAIL-resistant A549 cells to TRAIL-mediated apoptosis. Combined treatment with SFN and TRAIL induced chromatin condensation, DNA fragmentation, annexin V staining and sub-G(1) phase DNA content. These indicators of apoptosis correlate with the induction of caspase-3 activity that results in the cleavage of poly(ADP-ribose) polymerase and the release of lactate dehydrogenase. Both the cytotoxic effect and apoptotic characteristics induced by combined treatment were significantly inhibited by z-DEVD-fmk, a caspase-3 inhibitor, demonstrating the important role of caspase-3 in the observed cytotoxic effect. Combined treatment also triggered the activation of p38 MAPK and JNK, and downregulation of ERK and Akt. Inhibitors of ERK (PD98059) or Akt (LY294002), but not p38 MAPK, resulted in significantly decreased cell viability. Although the activation of JNK was increased in response to combined treatment, inhibition of the JNK pathway significantly attenuated cell viability. These results indicate that caspase-3 is a key regulator of apoptosis in response to combined SFN and TRAIL in human lung adenocarcinoma A549 cells through downregulation of ERK and Akt.
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PMID:Sulforaphane sensitizes tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis through downregulation of ERK and Akt in lung adenocarcinoma A549 cells. 1718 64

Previous studies have shown that oridonin, a diterpenoid isolated from Rabdosia rubescens, was able to inhibit proliferation and induce apoptosis in several cell types. But the mechanisms remain poorly understood. In this study, we investigated the apoptosis-inducing effect and mechanisms of action of oridonin in human osteosarcoma cells. Our results demonstrated that oridonin induced concentration- and time-dependent suppression of proliferation and activation of apoptosis in U2OS, MG63 and SaOS-2 osteosarcoma cell lines. Oridonin induced the release of cytochrome c accompanied by activation of caspase-9, caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP). These events were all inhibited by z-VAD-fmk, a universal inhibitor of caspases. Oridonin treatment dephosphorylated constitutively active AKT, FOXO transcription factor, and glycogen synthase kinase 3 (GSK3). In addition, oridonin decreased the phosphorylation of ERK and increased the phosphorylation of p38 MAPK and JNK. Furthermore, oridonin treatment down-regulated the expression of the inhibitor of apoptosis protein(IAP) in osteosarcoma cells. All together, our results suggested that oridonin is able to inactivate Akt and ERK and activate p38 MAPK and JNK signalling pathways in osteosarcoma cells causing the suppression of proliferation and induction of mitochondria- and caspase-dependent apoptosis.
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PMID:Oridonin induced apoptosis through Akt and MAPKs signaling pathways in human osteosarcoma cells. 1721 75

p53 is activated genetically by a set of kinases that are components of the calcium calmodulin kinase superfamily, including CHK2, AMP kinase, and DAPK-1. In dissecting the mechanism of DAPK-1 control, a novel mutation (N1347S) was identified in the death domain of DAPK-1. The N1347S mutation prevented the death domain module binding stably to ERK in vitro and in vivo. Gel filtration demonstrated that the N1347S mutation disrupted the higher order oligomeric nature of the purified recombinant death domain miniprotein. Accordingly, the N1347S death domain module is defective in vivo in the formation of high molecular weight oligomeric intermediates after cross-linking with ethylene glycol bis(succinimidylsuccinate). Full-length DAPK-1 protein harboring a N1347S mutation in the death domain was also defective in binding to ERK in cells and was defective in formation of an ethylene glycol bis(succinimidylsuccinate)-cross-linked intermediate in vivo. Full-length DAPK-1 encoding the N1347S mutation was attenuated in tumor necrosis factor receptor-induced apoptosis. However, the N1347S mutation strikingly prevented ERK:DAPK-1-dependent apoptosis as defined by poly(ADP-ribose) polymerase cleavage, Annexin V staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling imaging. Significant penetrance of the N1347S allele was identified in normal genomic DNA indicating the mutation is germ line, not tumor derived. The frequency observed in genomic DNA was from 37 to 45% for homozygous wild-type, 41 to 47% for heterozygotes, and 12 to 15% for homozygous mutant. These data highlight a naturally occurring DAPK-1 mutation that alters the oligomeric structure of the death domain, de-stabilizes DAPK-1 binding to ERK, and prevents ERK:DAPK-1-dependent apoptosis.
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PMID:A germ line mutation in the death domain of DAPK-1 inactivates ERK-induced apoptosis. 1724 21

Quinolone(s) (QNs) is widely used in infection therapy due to its good antimicrobial characteristics. However, QNs-induced arthropathy of immature animals has led to restrictions on the therapeutic use of these antimicrobial agents. The exact mechanism(s) of QNs-induced chondrotoxicity remain unknown. In the present study, we investigated the possible mechanism of ofloxacin (one typical QNs)-induced injuries of chondrocytes. Juvenile rabbit joint chondrocytes cultured in alginate microspheres were incubated with ofloxacin at concentrations of 0, 2, 5, 10, 20, and 40 microg/ml for up to 96 h. Concentration of 10 microg/ml ofloxacin induced apoptosis of chondrocyte with visible apoptotic signs, including degradation of poly(ADP-ribose) polymerase, caspase-3 activation, and DNA ladder formation. Furthermore, extracellular signal-regulated kinase 1/2 (phospho-ERK1/2) and growth factor receptor-bound protein 2 (Grb2) were significantly reduced, and similar changes were also observed in the beta(1)-integrin receptor as assessed by immunoblotting. However, the mRNA level of beta(1)-integrin obtained from reverse transcription-polymerase chain reaction remained unchanged. Results of beta(1)-integrin immunoprecipitation have also shown that beta(1)-integrin did not interact with activated intracellular signaling proteins. In addition, ofloxacin did not induce apoptosis and decrease beta(1)-integrin expression in chondrocytes supplemented with Mg(2+), and the ofloxacin-induced apoptosis was caspase-8-dependent, inhibition of which did not affect the expression mode of phospho-ERK1/2 and beta(1)-integrin. Our results demonstrate that ofloxacin affects beta(1)-integrin receptor functions and the ERK mitogen-activated protein kinase signaling pathway, causing caspase-8-dependent apoptosis after exposure of 48 h.
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PMID:Apoptosis in microencapsulated juvenile rabbit chondrocytes induced by ofloxacin: role played by beta(1)-integrin receptor. 1740 Aug 90

Homocysteine (HCY) is toxic on blood vessels, but a potential direct toxicity of HCY on the heart is unknown. We addressed this issue by exposing H9C2 cardiomyocytes to HCY (0.1-5 mM) for up to 6h. At these concentrations, HCY reduced cell viability, induced necrosis and apoptosis and triggered the cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP). This was associated with the intracellular generation of the potent oxidant peroxynitrite. Removing peroxynitrite by the decomposition catalyst FeTPPS considerably reduced LDH release, DNA fragmentation, cleavage of caspase-3 and PARP, and restored normal cell morphology. In additional experiments performed in primary rat ventricular cardiomyocytes, HCY (1 mM, 6h) activated the phosphorylation of the MAP kinases ERK and JNK, two essential stress signaling kinases regulating myocardial apoptosis, hypertrophy and remodeling. These results provide the first demonstration that HCY kills cardiomyocytes through the generation of peroxynitrite and can activate key signaling cascades in the myocardium.
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PMID:Homocysteine induces cell death in H9C2 cardiomyocytes through the generation of peroxynitrite. 1754 63

We conducted our study to assess the antiproliferative and proapoptotic potential of hecogenin and tigogenin, two saponins which are structurally similar to diosgenin. We particularly focused our attention on mitogen-activated protein kinase (MAPK) activation in relation to apoptosis but also with the COX-2 expression and activity. Rheumatoid arthritis (RA) synoviocytes were isolated from fresh synovial biopsies obtained from five RA patients undergoing hip arthroplasty. Measurement of cell proliferation was determined using the MTT assay. Apoptosis was evaluated by studying caspase-8, caspase-9 and caspase-3 activities but also by quantification of DNA fragmentation. Quantification of human phospho-MAPKs was realized by ELISA. COX-2 expression was demonstrated by Western blot analysis and COX-2 activity by assay of endogenous prostaglandin E2 (PGE2) production. Tigogenin was more effective than hecogenin in inducing apoptosis in human RA fibroblast-like synoviocytes (FLS) which was caspase dependent but poly(ADP-ribose) polymerase independent and characterized by DNA fragmentation. Our results demonstrated hecogenin- and tigogenin-induced apoptosis through activation of p38 without affecting the JNK and ERK pathways. Indeed, pretreatment with a p38 inhibitor decreased saponin-induced apoptosis with a significant decrease in DNA fragmentation. Furthermore, the rate of apoptosis induced by hecogenin or tigogenin was associated with overexpression of COX-2 correlated with overproduction of endogenous PGE2. These new results provide strong evidence that a family of structurally similar plant steroids is capable of inducing apoptosis in human RA FLS with different rates and different signalling pathways. This study also confirms the discussed appearance of the downregulation or upregulation of COX-2 in cell apoptosis as a function of cell type.
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PMID:Inhibition of human rheumatoid arthritis synovial cell survival by hecogenin and tigogenin is associated with increased apoptosis, p38 mitogen-activated protein kinase activity and upregulation of cyclooxygenase-2. 1778 75

We previously showed that matrix metalloproteinase (MMP)-9 inhibition using an adenovirus-mediated delivery of MMP-9 small interfering RNA (Ad-MMP-9), caused senescence in medulloblastoma cells. Regardless of whether or not Ad-MMP-9 would induce apoptosis, the possible signaling mechanism is still obscure. In this report, we demonstrate that Ad-MMP-9 induced apoptosis in DAOY cells as determined by propidium iodide and terminal deoxynucleotidyltransferase-mediated nick end labeling staining. Ad-MMP-9 infection induced the release of cytochrome c, activation of caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase. Ad-MMP-9 infection stimulated ERK, and electrophoretic mobility shift assay indicated an increase in NF-kappaB activation. ERK inhibition, using a kinase-dead mutant for ERK, ameliorated NF-kappaB activation and caspase-mediated apoptosis in Ad-MMP-9-infected cells. beta1-Integrin expression in Ad-MMP-9-infected cells also increased, and this increase was reversed by the reintroduction of MMP-9. We found that the addition of beta1 blocking antibodies inhibited Ad-MMP-9-induced ERK activation. Taken together, our results indicate that MMP-9 inhibition induces apoptosis due to altered beta1-integrin expression in medulloblastoma. In addition, ERK activation plays an active role in this process and functions upstream of NF-kappaB activation to initiate the apoptotic signal.
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PMID:Blockade of tumor growth due to matrix metalloproteinase-9 inhibition is mediated by sequential activation of beta1-integrin, ERK, and NF-kappaB. 3315 22

Smilax glabra Roxb. (SGR) is the root of a traditional Chinese herb, referred to as tu fu ling in Chinese medicine. It is an inexpensive traditional Chinese medicine commonly used for the treatment of liver diseases, and a few studies have indicated that SGR has anti-hepatocarcinogenic and anti-cancer growth activities. In the current study, raw SGR plant was extracted with Accelerate Solvent Extractor, and the molecular mechanism by which S. glabra Roxb. extract (SGRE) has an anti-proliferative effect on the human hepatoma cell lines, HepG2 and Hep3B, was determined. We showed that SGRE inhibited HepG2 and Hep3B cell growth by causing cell-cycle arrest at either S phase or S/G2 transition and induced apoptosis, as evidenced by a DNA fragmentation assay. SGRE-induced apoptosis by alternation of mitochondrial transmembrane depolarization, release of mitochondrial cytochrome c, activation of caspase-3, and cleavage of poly(ADP-ribose) polymerase. The SGRE-mediated mitochondria-caspase dependent apoptotic pathway also involved activation of p38, JNK, and ERK mitogen-activated protein kinase signaling. Isometric compounds of astilbin (flavonoids) and smilagenin (saponin) have been identified as the main chemical constituents in SGRE by HPLC-MS/MS. These results have identified, for the first time, the biological activity of SGRE in HepG2 and Hep3B cells and should lead to further development of SGR for liver disease therapy.
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PMID:Anti-proliferative and pro-apoptotic effect of Smilax glabra Roxb. extract on hepatoma cell lines. 1799 28

Six genes confer a high risk for developing breast cancer (BRCA1/2, TP53, PTEN, STK11, CDH1). Both BRCA1 and BRCA2 have DNA repair functions, and BRCA1/2 deficient tumors are now being targeted by poly(ADP-ribose) polymerase inhibitors. Other genes conferring an increased risk for breast cancer include ATM, CHEK2, PALB2, BRIP1 and genome-wide association studies have identified lower penetrance alleles including FGFR2, a minor allele of which is associated with breast cancer. We review recent findings related to the function of some of these genes, and discuss how they can be targeted by various drugs. Gaining deeper insights in breast cancer susceptibility will improve our ability to identify those families at increased risk and permit the development of new and more specific therapeutic approaches.
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PMID:Hereditary breast cancer: new genetic developments, new therapeutic avenues. 1857 92

The majority of patients with HER2-overexpressing metastatic breast cancer who initially respond to the HER2-targeted antibody trastuzumab show disease progression within 1 year. The identification of novel agents that effectively inhibit survival of cancer cells that have progressed on trastuzumab is critical for improving outcome for this patient population. In the current study, we show that the phenolic compound nordihydroguaiaretic acid (NDGA) promoted cell death of trastuzumab-naive and trastuzumab-refractory HER2-overexpressing breast cancer cells. NDGA induced DNA fragmentation, cleavage of poly(ADP-ribose) polymerase and caspase-3, and inhibition of colony formation. In addition, NDGA inhibited insulin-like growth factor-I and HER2 signaling in trastuzumab-refractory cells, with reduced downstream phosphatidylinositol-3 kinase/Akt signaling. Importantly, combination treatment with NDGA and trastuzumab suppressed proliferation and survival of trastuzumab-refractory cells to a greater degree than either agent alone, suggesting that NDGA increases the sensitivity of refractory cells to trastuzumab. Derivatives of NDGA are currently in clinical trial for other solid tumors. Our data strongly support further study of NDGA as a potential therapeutic against breast cancers that have progressed on trastuzumab.
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PMID:Nordihydroguaiaretic acid, a cytotoxic insulin-like growth factor-I receptor/HER2 inhibitor in trastuzumab-resistant breast cancer. 1864


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