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

---

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

To obtain insight into the identity of chemicals associated with the mutagenicity of United States National Institute of Standards and Technology (NIST) Standard Reference Materials SRM 1649 (urban dust) and SRM 1650 (diesel particulate), parallel mutagenicity tests and chemical analyses were performed on dichloromethane and sequential organic extracts of these samples. SRM 1649 and 1650 were sequentially extracted with five organic solvents of increasing polarity, in order to partition mutagenic components into discrete fractions. The solvents (with associated polarity index) were as follows: (1) hexane (0.0); (2) hexane:diethyl ether 9:1 (0.29); (3) hexane:diethyl ether 1:1 (1.45); (4) diethyl ether (2.9); (5) methanol (6.6). 0.9270 g of SRM 1649, and 0.0510 g of SRM 1650 were each extracted three times with 8 ml of each of the solvents, the three aliquots were pooled, and analysed for target organics or solvent-exchanged into DMSO for mutagenicity testing in Salmonella typhimurium strains TA98 and TA100. The dichloromethane extracts of SRM 1649 and SRM 1650 contained direct-acting mutagens in Salmonella strains TA98 and TA100; SRM 1650 was significantly more potent than SRM 1649 in either strain. Addition of S9 caused a large decrease in mutagenicity of each extract, although SRM 1650 remained more potent. An interesting pattern of mutagenicity was observed for the sequential extracts of SRM 1649 and SRM 1650: the mutagenic potency of SRM 1649 extracts increased with increasing polarity of the extraction solvent while the response of the SRM 1650 extracts was the opposite. This suggests that the direct-acting mutagens in SRM 1650 are unlike those in SRM 1649. The response, though diminished, was largely unchanged when S9 was included in the test mixture. Chemical analyses on the various extracts were performed using a Hewlett-Packard model 5890 gas chromatograph equipped with a model 5970B mass selective detector (GC-MSD), and a 0.3 microns film thickness cross-linked methyl silicone capillary column (HP 1909A-101). Selected ion monitoring (SIM) methods were used to analyze for 105 target compounds including PAHs and nitro-PAHs. Chemical analysis of the dichloromethane extracts of SRM 1649 and SRM 1650 identified three main classes of compounds: polyaromatic hydrocarbons (PAH), nitro-polyaromatic hydrocarbons (NO2-PAHs) and heterocyclics. The concentration of target compounds and the proportion of nitro-PAHs and heterocyclic compounds were considerably greater in SRM 1650 than in SRM 1649, consistent with the observed differences in their mutagenic potency. However, the different responses of the dichloromethane extracts in TA98 and TA100 suggest the presence of different (unidentified) compounds.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Mutagenicity and chemical analysis of sequential organic extracts of airborne particulates. 137 Jan

EMT-6 tumor cell killing by decays from 3H and 125I incorporated by adduct formation of radiolabeled sensitizers was studied in vitro. Hypoxic radiosensitizers become covalently bound to cellular molecules after metabolic reduction, and EMT-6 tumor cells can tolerate over 10(9) adducts/cell of misonidazole without loss of colony-forming ability. Cells were incubated under hypoxic conditions in the presence of [3H]misonidazole or [125I]iodoazomycinriboside for various times and the amounts of bound 3H and 125I were determined. Cells were stored as monolayers at 22 degrees C, in suspension culture at 4 degrees C, and frozen in complete medium plus 8% DMSO at -196 degrees C for various times to facilitate the accumulation of radioactive decays before plating in vitro for colony-forming assays at 37 degrees C. At 22 degrees C in monolayer culture, EMT-6 tumor cells tolerated 950 and 1720 decays/cell of 3H and 125I, respectively, without evidence of radiotoxicity. This number of decays/cell over the exposure times used represents 1.54 x 10(6) 3H/cell and 8.4 x 10(4) 125I/cell, respectively. Significant cell killing was detected after similar amounts of isotope decay when cells were held at 4 degrees C. When cells were frozen in the presence of 8% DMSO, they were more resistant to inactivation by isotope decays or by gamma rays than cells in liquid phase at 4 degrees C. These data suggest that selective hypoxic tumor cell suicide by 3H or 125I decays from bound sensitizer at 37 degrees C will be an inefficient process, at least for drugs with specific activities as tested. These data are consistent with data on cell inactivation by isotopes incorporated into cells by other procedures.
...
PMID:Killing of EMT-6 cells by decays from isotopes incorporated on sensitizer adducts. 143 7

Aluminum (Al) overload in dialysis patients and experimental animals is associated with the development of anemia. However, the precise mechanisms of erythrocyte Al uptake and toxicity are poorly understood. Al accumulation, hemoglobin (Hb) synthesis and cell growth were evaluated in dimethylsulfoxide (DMSO)-induced Friend erythroleukemia cells (FEC), a model system for erythroid differentiation. FEC were grown in media containing either Al citrate, transferrin-aluminum (Tf-Al), Tf or no additions. Al accumulation occurring only in cells grown in Tf-Al containing media was detected at 24 hours and increased linearly up to 96 hours after induction. By 96 hours, 200 +/- 36 micrograms Al/liter lysed cells were detected in Tf-Al grown cells versus 5 +/- 1 micrograms Al/liter lysed cells in cells grown in Al citrate (P less than 0.001). Tf-Al inhibited Hb synthesis at 72 hours after induction. At 96 hours 50 +/- 15% cells were benzidine positive when grown in Tf-Al compared to 76 +/- 15% in Al citrate (P less than 0.001). FEC grown in increasing concentrations of Tf-Al (100 to 500 micrograms/ml) showed inhibition of Hb synthesis at lower concentrations of Tf-Al at 100 micrograms/ml than for cell growth at 300 micrograms/ml. Higher concentrations of Tf-Al (greater than 300 micrograms/ml) did not further inhibit Hb synthesis or cell growth. Iron (Fe) and Tf uptake were increased in Al loaded FEC compared to control cells. The increased Tf uptake was probably the result of increased Tf receptor expression on FES since Tf cell cycling time was unchanged. These data indicate that Al utilizes the Tf uptake pathway for entry into erythrocyte precursors. Al is toxic at sites distal to Fe uptake, possibly at the heme and/or globin synthetic pathways, resulting in decreased Hb synthesis and cell growth.
...
PMID:Aluminum inhibits hemoglobin synthesis but enhances iron uptake in Friend erythroleukemia cells. 230 57

We used specific antisera and immunohistochemical methods to investigate the subcellular localization and expression of Bcr, Abl, and Bcr-Abl proteins in leukemic cell lines and in fresh human leukemic and normal samples at various stages of myeloid differentiation. Earlier studies of the subcellular localization of transfected murine type IV c-Abl protein in fibroblasts have shown that this molecule resides largely in the nucleus, whereas transforming deletion variants are localized exclusively in the cytoplasm. Here, we demonstrate that the murine type IV c-Abl protein is also found in the nucleus when overexpressed in a mouse hematopoietic cell line. However, in both normal and leukemic human hematopoietic cells, c-Abl is discerned predominantly in the cytoplasm, with nuclear staining present, albeit at a lower level. In contrast, normal endogenous Bcr protein, as well as the aberrant p210BCR-ABL and p190BCR-ABL proteins consistently localize to the cytoplasm in both cell lines and fresh cells. The results with p210BCR-ABL were confirmed in a unique Ph1-positive chronic myelogenous leukemia (CML) cell line, KBM5, which lacks the normal chromosome 9 and hence the normal c-Abl product. Because the p210BCR-ABL protein appears cytoplasmic in both chronic phase and blast crisis CML cells, as does the p190BCR-ABL in Ph1-positive acute leukemia, a change in subcellular location of Bcr-Abl proteins between cytoplasm and nucleus cannot explain the different spectrum of leukemias associated with p210 and p190, nor the transition from the chronic to the acute leukemia phenotype seen in CML. Further analysis of fresh CML and normal hematopoietic bone marrow cells reveals that p210BCR-ABL, as well as the normal Bcr and Abl proteins, are expressed primarily in the early stages of myeloid maturation, and that levels of expression are reduced significantly as the cells mature to polymorphonuclear leukocytes. Similarly, a decrease in Bcr and Abl levels occurs in HL-60 cells induced by DMSO to undergo granulocytic differentiation. The action of p210BCR-ABL and its normal counterparts may, therefore, take place during the earlier stages of myeloid development.
...
PMID:Subcellular localization of Bcr, Abl, and Bcr-Abl proteins in normal and leukemic cells and correlation of expression with myeloid differentiation. 840 45

MCF-7 human breast carcinoma cultures grown in the presence of 17-beta estradiol form solid, multicellular nodules, a process that reflects changes in cell-substrate adhesions and loss of growth inhibition. We examined the effects of estradiol on the status of tyrosine phosphorylation in focal adhesion kinase (FAK) and the association of FAK with paxillin using immunoprecipitations and then probing western blots for FAK, phosphotyrosine, and paxillin. Culture of MCF-7 cells for seven days in the presence of 1 nM E2 resulted in decreased tyrosine phosphorylation of FAK compared to controls. The estradiol-induced effect was blocked by 100 nM of the estrogen receptor antagonist 4-hydroxytamoxifen, indicating dephosphorylation of FAK is an estrogen receptor-mediated event. FAK immunoprecipitated from either estradiol or DMSO-treated cells phosphorylated the exogenous substrate poly(Glu,Tyr), suggesting that the potential kinase activity of FAK was not changed by estradiol. Estradiol treatment also resulted in a reduced association between FAK and paxillin. The decreased phosphorylation levels and reduced association between FAK and paxillin may be important steps leading to the loss of stable focal contacts and loss of growth inhibition during MCF-7 nodulation.
...
PMID:Decreased tyrosine phosphorylation of focal adhesion kinase after estradiol treatment of MCF-7 human breast carcinoma cells. 987 83

The roles of the protein tyrosine kinases Pyk2 (also called RAFTK or CAK beta) and Syk in the process of functional activation of human myeloid cells were examined. During granulocytic differentiation of HL-60 cells with dimethyl sulfoxide (DMSO), the amounts of Pyk2 and beta2 integrin increased, whereas the amount of Syk was abundant before differentiation and did not change during differentiation. When the granulocytic cells were stimulated with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), tyrosine phosphorylation of Pyk2 occurred promptly and subsequent association of Pyk2 with beta2 integrin was detected. In contrast, Syk was not tyrosine phosphorylated by fMLP stimulation but constitutively associated with beta2 integrin. Stimulation with fMLP also caused the alteration of beta2 integrin to an activated form, a finding that was confirmed by the observation of fMLP-induced cell attachment on fibrinogen-coated dishes and inhibition of this attachment by pretreatment with anti-beta2 integrin antibody. Cell attachment to fibrinogen caused the enhanced tyrosine phosphorylation of Pyk2 and the initial tyrosine phosphorylation of Syk, which was also inhibited by pretreatment with anti-beta2 integrin antibody. In vitro kinase assays revealed that Pyk2 and Syk represented kinase activities to induce tyrosine phosphorylation of several molecules in the anti-beta2 integrin immunoprecipitates of the attached cells. These results showed that Pyk2 is involved in the functional activation of granulocytic cells in 2 signaling pathways: an fMLP receptor-mediated "inside-out" signaling pathway that might cause beta2 integrin activation and a subsequent beta2 integrin-mediated "outside-in" signaling pathway. Syk was activated in relation to cell attachment to fibrinogen as a result of "outside-in" signaling, although it was already associated with beta2 integrin before fMLP stimulation. (Blood. 2000;96:1733-1739)
...
PMID:Pyk2 and Syk participate in functional activation of granulocytic HL-60 cells in a different manner. 1096 71

Epidemiological studies demonstrate an association between increased human morbidity and mortality with exposure to air pollution particulate matter. We hypothesized that such effects may be associated with the ability of the particles to mediate generation of reactive oxygen species (ROS), either directly, via interaction with ambient oxygen or indirectly through initiation of an oxidative burst in phagocytes. To test this hypothesis, we determined 8-oxo-dG formation as a measure of direct generation of ROS, in response to particulate exposures to 2'-deoxyguanosine (dG), free and in calf thymus DNA in aerated solutions as the target molecule and cell culture, to assess the relationship between induction of oxidative damage, particulate metal content and metal bioreactivity. The HPLC-ECD technique was employed for separation and quantification of 8-oxo-dG, the most widely recognized marker of DNA oxidation. Particles used in this study include: Arizona desert dust (AZDD), coal fly ash (CFA and ECFA), oil fly ash (OFA and ROFA), and ambient air [SRM 1649 and Dusseldorf (DUSS), Germany]. The major difference between these particles is the concentration of water-soluble metals. The fly ash particulates OFA and ROFA showed a significant dose-dependent increase in dG hydroxylation to 8-oxo-dG formation over the control dG (p < 0.05), with yields 0.03 and 1.25% at the highest particulate concentration (1 mg/mL). Metal ion chelators and DMSO, a hydroxyl radical scavenger, inhibited this hydroxylation. In contrast, desert dust, coal fly ash and urban air particles induced 8-oxo-dG with yields ranging from 0.003 to 0.006%, respectively, with levels unaffected by pretreatment of the particles with metal ion chelators or addition of DMSO to the incubation mixture. When calf thymus DNA was used as a substrate, all the particles induced 8-oxo-dG in a pattern similar to that observed for dG hydroxylation, but with relatively less yield. Treatment of the particles with metal ion chelator before reacting with DNA or addition of catalase in the incubation mixture, suppressed 8-oxo-dG formation significantly (p < 0.05) in oil-derived fly ash particles only. To determine whether the oxidative responses of these particulates as shown in cell-free systems were consistent with responses using a more biologically relevant environment, human airway epithelial cells were treated with the particulates and induction of 8-oxo-dG was determined. All particles induced 8-oxo-dG in the DNA of cells above culture control, except CFA. Cells exposed to 10-400 mg/mL of ROFA for 2 h induced a dose-dependent increase in 8-oxo-dG formation. Treatment of ROFA with metal ion chelator attenuated these effects. Overall, damage enhancement by particulates in dG, calf thymus, and cellular DNA as determined by 8-oxo-dG formation under aerobic conditions is consistent with the concentration of water-soluble, not the total metal content of the particle.
...
PMID:Air pollution particles mediated oxidative DNA base damage in a cell free system and in human airway epithelial cells in relation to particulate metal content and bioreactivity. 1145 35

Exposure to particulate matter (PM) is associated with several health effects including lung cancer. However, the mechanisms of particle-induced carcinogenesis are not fully understood. The main aim of this study was to investigate the genotoxicity of PM in relation to particle-cell interactions and to study the effect of removal of DNA-damaging substances by extraction of PM with different solvents. Genotoxicity was analyzed by means of the comet assay after exposure of cultured human fibroblasts to urban dust particles (SRM 1649). It was found that PM induced DNA damage in a dose-dependent manner and that cells interacting with PM suffered more DNA single-strand breaks relative to other cells. The genotoxicity of PM was significantly reduced after extraction with dichloromethane (DCM), dimethyl sulfoxide (DMSO) and water, but not with acetone and hexane. However, the insoluble particle core still induced DNA single-strand breaks. The extracts were further investigated in cell-free systems. Analysis of aromatic DNA adducts with 32P-HPLC showed that the DMSO and DCM extracts contained most of the DNA-reactive polyaromatic compounds (PACs). Further, the formation of 8-oxo-2'-deoxyguanosine (8-oxodG) upon incubation of the extracts with 2'-deoxyguanosine (dG) showed that the water extract contained most of the oxidizing substances. Thus, the genotoxicity of PM was caused both by adduct-forming PACs and oxidizing substances as well as the insoluble particle-core. This study showed that all these factors together contribute to explaining the mechanisms of PM genotoxicity.
...
PMID:Genotoxicity of airborne particulate matter: the role of cell-particle interaction and of substances with adduct-forming and oxidizing capacity. 1557 34

We have previously demonstrated that constant 20 mmHg extracellular pressure increases serum-opsonized latex bead phagocytosis by phorbol 12-myristate 13-acetate (PMA)- differentiated THP-1 macrophages in part by inhibiting focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK). Because p38 MAPK is activated by physical forces in other cells, we hypothesized that modulation of p38 MAPK might also contribute to the stimulation of macrophage phagocytosis by pressure. We studied phagocytosis in PMA-differentiated THP-1 macrophages, primary human monocytes, and human monocyte-derived macrophages (MDM). p38 MAPK activation was inhibited using SB-203580 or by p38 MAPKalpha small interfering RNA (siRNA). Pressure increased phagocytosis in primary monocytes and MDM as in THP-1 cells. Increased extracellular pressure for 30 min increased phosphorylated p38 MAPK by 46.4 +/- 20.5% in DMSO-treated THP-1 macrophages and by 20.9 +/- 9% in primary monocytes (P < 0.05 each). SB-203580 (20 microM) reduced basal p38 MAPK phosphorylation by 34.7 +/- 2.1% in THP-1 macrophages and prevented pressure activation of p38. p38 MAPKalpha siRNA reduced total p38 MAPK protein by 50-60%. Neither SB-203580 in THP-1 cells and peripheral monocytes nor p38 MAPK siRNA in THP-1 cells affected basal phagocytosis, but each abolished pressure-stimulated phagocytosis. SB-203580 did not affect basal or pressure-reduced FAK activation in THP-1 macrophages, but significantly attenuated the reduction in ERK phosphorylation associated with pressure. p38 MAPKalpha siRNA reduced total FAK protein by 40-50%, and total ERK by 10-15%, but increased phosphorylated ERK 1.4 +/- 0.1-fold. p38 MAPKalpha siRNA transfection did not affect the inhibition of FAK-Y397 phosphorylation by pressure but prevented inhibition of ERK phosphorylation. Changes in extracellular pressure during infection or inflammation regulate macrophage phagocytosis by a FAK-dependent inverse effect on p38 MAPKalpha that might subsequently downregulate ERK.
...
PMID:Activation of p38 MAPKalpha by extracellular pressure mediates the stimulation of macrophage phagocytosis by pressure. 1562 2

The main goal of this study was to develop a dispersed polymeric drug delivery system for verteporfin, suitable for intravenous administration and capable of improving its phototherapeutic index and minimizing the side effects. To achieve this objective, two types of verteporfin-loaded nanoparticles (167 and 370 nm in diameter) based on poly(D,L-lactide-co-glycolide) were prepared using the salting-out technique and were first tested on EMT-6 mammary tumor cells in comparison with an aqueous solution (DMSO/PBS). It was observed that small nanoparticles exhibited greater photocytotoxicity compared to large nanoparticles or DMSO/PBS, and the photocytotoxic efficiency was graded as small nanoparticles>DMSO/PBS>large nanoparticles. Furthermore, verteporfin, entrapped into small nanoparticles transferred to serum proteins more rapidly than when dissolved in DMSO/PBS. Drug clearance, measured by skin phototoxicity investigated in mice exposed to simulated sunlight 15 to 150 min after the injection of small nanoparticles was modest at early light exposure times with the small nanoparticles and diminished rapidly with later exposure times. Tumor bioassay results indicated that verteporfin incorporated into small nanoparticles effectively controlled tumor growth for 20 days in mice with early light irradiation times following drug administration.
...
PMID:In vitro and in vivo activities of verteporfin-loaded nanoparticles. 1571 May 2


1 2 3 4 Next >>

---