Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate the origin of DNA repair in rat pleural mesothelial cells (RPMC) exposed to asbestos fibers, poly(ADP-ribose) polymerase (PARP) activity was measured in the asbestos-treated cells. As bleomycin has been shown to activate poly(ADP-ribose) synthesis in several cell systems, the response to bleomycin with regard to PARP assay was first investigated. Bleomycin produced a dose-dependent increase of poly(ADP-ribose) synthesis in RPMC. Likewise both chrysotile and crocidolite fibers produced a concentration-dependent PARP activation indicating that the formation of DNA strand breaks is one type of damage produced by asbestos in RPMC. Enhancement of DNA repair, assessed by the measurement of [3H] methylthymidine incorporation in growth arrested cells, was not detectable in the presence of 3-methoxybenzamide (3-MBA), a PARP inhibitor, confirming a relation between PARP activation and DNA repair. The participation of DNA breakage in asbestos toxicity on RPMC was determined by the colorimetric 3-4(5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. There was no relationship between DNA breakage and cytotoxicity since the use of PARP inhibitors did not change cell viability. These results indicate that asbestos produce DNA damage that is repaired in RPMC.
 ...
PMID:Synthesis of poly(ADP-ribose) in asbestos treated rat pleural mesothelial cells in culture. 750 Sep 78

B-chronic lymphocytic leukaemia (B-CLL) is characterized by the accumulation of long-lived CD5+ B lymphocytes. The effect of mitoxantrone, a topoisomerase II inhibitor, on B-CLL cells was studied. Treatment of B-CLL cells for 48 h with mitoxantrone (0.5 microg/ml) induced a decrease in cell viability as determined by MTT assay. The IC50 calculated for the cells of three patients was 0.7 microg/ml for two of them and 1.4 microg/ml for the third. In all three patients the maximum effect was observed with 2 microg/ml. An additive cytotoxic effect was observed when mitoxantrone (0.5 microg/ml) was combined with fludarabine (5 microg/ml). Mitoxantrone induced DNA fragmentation and the proteolytic cleavage of poly(ADP-ribose) polymerase (PARP), a marker of the activation of caspases, in all the patients studied, demonstrating that the cytotoxic effect of mitoxantrone was due to induction of apoptosis. These results suggest that mitoxantrone, and possibly other topoisomerase II inhibitors, may be used in the chemotherapy of B-CLL, and that combination of mitoxantrone with fludarabine or other drugs could improve the effectiveness of the treatment.
 ...
PMID:Mitoxantrone, a topoisomerase II inhibitor, induces apoptosis of B-chronic lymphocytic leukaemia cells. 945 Aug 3

Streptozotocin (STZ) is believed to induce pancreatic beta cell death in mice by depleting the cell of NAD+NADH. The drug is known to cause a greater depletion of beta cell NAD+NADH in C57bl/6J mice than in Balb/c mice. To investigate the basis for this strain difference, we compared the effects of streptozotocin on poly(ADP-ribose)polymerase (PARP) activation - the major site of NAD consumption, and on mitochondrial activity - the major site of NAD production.%A significant strain difference was demonstrated in STZ-induced PARP activation (fmol NAD incorporated/min/microgram DNA+/-s.e.m.: Balb/c control 2.28+/-0.14, Balb STZ 3.11+/-0.25; C57bl/6J control 2.57+/-0.29, C57bl/6J STZ 4.17+/-0.24). In comparison, no strain difference could be demonstrated in hydrogen-peroxide-induced PARP activation. No strain differences could be detected in the activity of STZ-treated islet mitochondria as measured by determining ATP production (pmol/microgram protein/h+/-s. e.m.: Balb/c control 0.20+/-0.02, Balb/c STZ 0.15+/-0.02; C57bl/6J control 0.23+/- 0.03, C57bl/6J STZ 0.15+/-0.02) or by 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) dye reduction (change in optical density/mg protein+/-s.e.m.: Balb/c control 10.19+/-0.62, Balb/c STZ 6.01+/-1.17; C57bl/6J control 6. 15+/-0.98, C57bl/6J STZ 5.81+/-0.96).% The strain difference in STZ-induced NAD depletion appears to be due to a difference in NAD consumption and not a difference in a mitochondrial process involved in replacing decreasing NAD concentrations. It is unlikely that a strain difference in the enzymic activity of PARP is responsible for strain differences in the effects of STZ, as no strain differences in hydrogen-peroxide-induced PARP activation could be detected. Thus the greater PARP activation, NAD depletion and beta cell death observed in C57bl/6J islets may be due to greater levels of DNA damage or differences in the DNA excision repair processes.
 ...
PMID:Poly(ADP-ribose)polymerase activation determines strain sensitivity to streptozotocin-induced beta cell death in inbred mice. 992 81

The present study was undertaken to find potent molecules against the toxicity of nitrogen mustard mechlorethamine (HN2) on respiratory epithelial cells, using a human bronchial epithelial cell line (16HBE14o-) as an in vitro model. The compounds examined included inhibitors of poly(ADP-ribose) polymerase (PARP), sulfhydryl-group donors as nucleophiles, and iron chelators and inhibitors of lipid peroxidation as antioxidants. Their effectiveness was determined upon observance of metabolic dysfunction induced by HN2 following a 4-h exposure, using (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction and ATP-level assays as indicators. Moreover, the fluorescent probe, monobromobimane (mBBr), and 2',7'-dichlorofluorescin-diacetate (H2DCF-DA) were used to assess intracellular sulfhydryl and peroxide level modifications by flow cytometry, respectively, following a 3-h exposure. At last, cell death was assessed by flow cytometry using the propidium iodide (PI)-dye-exclusion assay following 24-h exposure. PARP inhibitors (niacinamide, 3-aminobenzamide, 6(5H)-phenanthridinone), and two sulfhydryl-group donors (N-acetylcysteine, WR-1065) were found to be effective in preventing HN2-induced metabolic dysfunction when added in immediate or delayed treatment with HN2. Only N-acetylcysteine, however, was found to prevent cell death induced by HN2, though it must be present at the time of the HN2 challenge. Flow cytometric measurements of intracellular sulfhydryl levels strongly suggested that N-acetylcysteine and WR-1065 are preventive in alkylation of cellular compounds, mainly by direct extracellular interaction with HN2. PARP inhibitors prevent secondary deleterious effects induced by HN2, considering metabolism dysfunction as the endpoint. Elsewhere, the oxidative stress appears to be a side effect in HN2 toxicity only upon considering the inefficiency of several antioxidants.
 ...
PMID:Protection from cytotoxic effects induced by the nitrogen mustard mechlorethamine on human bronchial epithelial cells in vitro. 1074 48

Prodigiosin is a red pigment produced by various bacteria including Serratia marcescens. Colorectal cancer is one of the most frequent malignancies and one of the most frequent causes of cancer death in the Western world. Its treatment is far from satisfactory and the challenge to oncologists is to find novel chemical entities with less toxicity and greater effectiveness than those used in current chemotherapy. Here we characterize the apoptotic action of prodigiosin in colon cancer cells. DLD-1 and SW-620 human colon adenocarcinoma cells, NRK and Swiss-3T3 nonmalignant cells were assayed by the MTT assay, fragmentation pattern of DNA, Hoechst 33342 staining and study of PARP cleavage by Western blot, in order to characterize the prodigiosin-induced apoptosis. Prodigiosin was purified and its structure was confirmed. Metastatic SW-620 cells were more sensitive to prodigiosin (IC50: 275 nM) than DLD-1. We did not observe a significant decrease in the viability of NRK cells. We confirmed that prodigiosin induces apoptosis in both cancer cell lines by the characteristic DNA laddering pattern and condensed nuclei or apoptotic bodies identified by fluorescence microscopy. These results indicate that prodigiosin induces apoptosis in colon cancer cells.
 ...
PMID:Prodigiosin-induced apoptosis in human colon cancer cells. 1138 4

TRAIL, Tumor necrosis factor-related apoptosis-inducing ligand), a member of the TNF family, is known to be cytotoxic for a high proportion of tumor cell lines. However, successful application of TRAIL in tumor therapy may depend on finding other agents that can potentiate its antitumor effects. The present study showed that the cytostatic/cytotoxic TRAIL activity against U937 cells could be significantly augmented by proteasome inhibitor PSI, as revealed by MTT assay. Increased cytostatic/cytotoxic effect on U937 cells by TRAIL/PSI combined treatment was caused by apoptosis, as shown by an increased PARP cleavage rate. TRAIL/PSI did not affect the level of mRNA expression for TRAIL receptors (DR4, DR5, DcR1) and other apoptosis signal transduction molecules (TRADD, caspase-8).
 ...
PMID:Augmented pro-apoptotic effects of TRAIL and proteasome inhibitor in human promonocytic leukemic U937 cells. 1139 70

Seven structurally related flavonoids including luteolin, nobiletin, wogonin, baicalein, apigenin, myricetin and fisetin were used to study their biological activities on the human leukemia cell line, HL-60. On MTT assay, wogonin, baicalein, apigenin, myricetin and fisetin showed obvious cytotoxic effects on HL-60 cells, with wogonin and fisetin being the most-potent apoptotic inducers among them. The cytotoxic effects of wogonin and fisetin were accompanied by the dose- and time-dependent appearance of characteristics of apoptosis including DNA fragmentation, apoptotic bodies and the sub-G1 ratio. Treatment with an apoptosis-inducing concentration of wogonin or fisetin causes rapid and transient induction of caspase 3/CPP32 activity, but not caspase 1 activity. Further, cleavage of poly(ADP-ribose) polymerase (PARP) and decrease of pro-caspase 3 protein were detected in wogonin- and fisetin-treated HL-60 cells. An increase in the pro-apoptotic protein, bax, and a decrease in the anti-apoptotic protein, Mcl-1, were detected in fisetin- and wogonin-treated HL-60 cells. However, Bcl-2, Bcl-XL, and Bad all remained unchanged in wogonin- and fisetin-treated HL-60 cells. In vitro chromatin digestion revealed that endonuclease activity was profoundly enhanced in wogonin- and fisetin-treated HL-60 cells, and the addition of ethylenediaminetetraacetic acid (EDTA) or ethyleneglycoltetraacetic acid (EGTA) into the reaction blocked endonuclease activation and at an optimum pH of 7.5. The caspase 3 inhibitor, Ac-DEVD-CHO, but not the caspase 1 inhibitor, Ac-YVAD-CHO, attenuated wogonin- and fisetin-induced DNA ladders, PARP cleavage, and endonuclease activation. Pretreatment of HL-60 cells with N-acetyl-cysteine or catalase efficiently inhibited H(2)O(2) (200 microM)-induced apoptosis, but showed no inhibitory effect on wogonin- and fisetin-induced DNA ladders, caspase 3 activation, or bax protein induction. Decrease in endogenous ROS production was detected in wogonin- and fisetin-treated HL-60 cells by DCHF-DA assay. In conclusion, our experiments indicate that a decrease in intracellular peroxide level was involved in wogonin- and fisetin-induced apoptosis; activation of caspase 3 and endonuclease, induction of bax protein and suppression of Mcl-1 protein were detected in the process.
 ...
PMID:Wogonin and fisetin induce apoptosis in human promyeloleukemic cells, accompanied by a decrease of reactive oxygen species, and activation of caspase 3 and Ca(2+)-dependent endonuclease. 1184 97

Neuroblastomas are the most common extracranial solid tumors of childhood. These tumors are associated with an overall poor prognosis, particularly for advanced stage disease. The benzoquinone ansamycin antibiotic, geldanamycin (GA), exhibits potent antitumor activity in certain cancer cell lines by destabilizing important signal transduction proteins (e.g., Raf-1 and Akt). The purpose of our study was to determine whether GA can alter the expression of Raf-1 and Akt, which have been shown to be critical for neuronal cell survival, and induce apoptosis of neuroblastoma cells. Human neuroblastoma cells (SH-SY5Y, SK-N-SH and LAN-1) were treated with GA for a variable period of time. Cell viability was assessed with MTT assays. Apoptosis was assessed with DNA fragmentation ELISA, TUNEL-flow cytometric assay, Western blot and caspase activities. We found that GA decreases cell viability and induces apoptosis in the SH-SY5Y human neuroblastoma cell line. These effects were mediated through activation of caspase-9 and -3, mitochondrial release of cytochrome c and subsequent PARP cleavage. GA-induced apoptosis was associated with a reduction in the level and activity of Raf-1 and Akt. The importance of these proteins was further demonstrated by induction of apoptosis in SH-SY5Y cells by a combination of U0126 (MEK1/2 inhibitor) and LY294002 (an inhibitor of PI3K). Similar to SH-SY5Y cells, other human neuroblastoma cells (SK-N-SH and LAN-1) were sensitive to the effects of GA-induced apoptosis. Taken together, our findings suggest that GA may be a novel therapeutic agent, which may be effective in the treatment of neuroblastomas.
 ...
PMID:Geldanamycin decreases Raf-1 and Akt levels and induces apoptosis in neuroblastomas. 1247 18

A human-human oligodendroglial cell line MO3.13 was chosen in this study to model the loss of oligodendrocytes that occurs during episodes of multiple sclerosis. The influence of mercuric chloride (HgCl(2)) upon cell viability specifically the mode of cell death, whether by an active apoptotic mechanism or passive necrosis was determined by morphological and biochemical analysis. Mitochondrial dehydrogenase activity MTT assay showed that HgCl(2) had toxic effects on MO3.13 cells at levels of (5-25 microM) with approximately 50% cell death observed at 58 microM. Death of cells was dependent on both time and concentrations of HgCl(2). Differentiated MO3.13 cells exposed to low concentrations (25 microM) of HgCl(2) exhibited features of apoptotic cell death, including cell shrinkage and chromatin condensation. High doses of HgCl(2) (>100 microM) induced death with characteristics of necrosis. Biochemical analysis showed that HgCl(2) activated the caspase family of proteases. This was measured directly by cleavage of fluorescent substrates and by immunoblotting assay of caspase substrate proteins; alpha-fodrin, lamin B and poly (ADP-ribose) polymerase (PARP). These results indicate that HgCl(2) is toxic at low concentrations for oligodendroglial cells and that the MO3.13 cell line dies in an apoptotic manner when exposed to low concentrations of HgCl(2). However, blood mercury concentrations in vivo in a normal population with amalgam restorations are lower by a factor of some 500 times than those causing toxicity in vitro suggesting a good safety margin in respect of environmental uptake.
 ...
PMID:Mercuric chloride: toxicity and apoptosis in a human oligodendroglial cell line MO3.13. 1250 20

Oligodendrocyte loss is a characteristic feature of several CNS disorders, including multiple sclerosis (MS) and spinal cord injury. However, the mechanisms responsible for oligodendrocyte destruction remain undefined. As recent studies have implicated peroxynitrite in the pathogenesis of both spinal cord injury and MS, we have examined whether peroxynitrite may mediate at least some of the oligodendrocyte damage and demyelination observed in these conditions. Primary rat oligodendrocytes were exposed to authentic peroxynitrite in vitro and assessed for cytotoxicity. Mitochondrial function, measured by the reduction of MTT to formazan, and mitochondrial membrane potential were used as indicators of cell viability. Cell death was quantitated by measuring either the release of lactate dehydrogenase from, or the uptake of propidium iodide into, damaged and dying cells. Peroxynitrite dose-dependently reduced the viability of primary oligodendrocytes and induced cell death. Furthermore, peroxynitrite significantly increased DNA strand breakage and the activity of poly(ADP-ribose) polymerase (PARP) in oligodendrocyte cultures. To identify whether PARP activation plays a role in peroxynitrite-induced oligodendrocyte toxicity, we examined the effects of the PARP inhibitors 3-aminobenzamide (3AB) and 5-iodo-6-amino-1,2-benzopyrone (INH(2)BP) on mitochondrial function and cell death in oligodendrocytes. The presence of 3AB and INH(2)BP did not protect oligodendrocytes from peroxynitrite-induced cytotoxicity. However, both compounds significantly reduced PARP activity in these cells. Primary oligodendrocytes generated from PARP-deficient mice were also highly susceptible to peroxynitrite-induced cell death. Therefore, our results show that peroxynitrite exerts cytotoxic effects on oligodendrocytes in vitro independently of PARP activation.
 ...
PMID:Peroxynitrite-induced oligodendrocyte toxicity is not dependent on poly(ADP-ribose) polymerase activation. 1250 1


1 2 3 4 5 6 7 8 9 10 Next >>