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

Crk II and Crk L have both cytosolic and nuclear functions. While Crk L is a bona fide nuclear signaling protein because of its ability to bind tyrosine-phosphorylated STAT5 and act as a transcriptional coactivator, the function of nuclear Crk II is less well understood. The present study was undertaken to investigate whether Crk II is in the nucleus, how Crk II translocates into the nucleus, whether it possesses a functional NES, and to determine if nuclear Crk II affects cell cycle checkpoints and promotes apoptosis. Toward this goal, we used several independent techniques to show that a significant percentage of the total endogenous Crk II partitions in the nucleus in mammalian cells, where it forms distinct complexes with DOCK180, Wee1, and Abl. We found no evidence that Crk II bound to Crm1 nor that the localization of GFP-Crk II was sensitive to LMB, an inhibitor of Crm1. To better define the significance of nuclear Crk II localization, we generated a GFP-Crk II protein (GFP-Crk-nuc) fused to three tandem nuclear localization signals derived from the SV40 large T-antigen. GFP-Crk-nuc exhibited exclusive nuclear localization, and in contrast to wild-type Crk, GFP-Crk-nuc expressing cells could not be propagated upon selection in G418-containing media, suggesting nuclear accumulation of Crk II caused either growth arrest or apoptosis. When transiently transfected cells were FACS sorted, GFP-expressing cells showed defective cell adhesion on tissue culture surfaces and showed an increased level of apoptosis assessed by pycnotic nuclei, annexin V staining, and PARP cleavage. Although we found that Crk II bound to the cell cycle protein Wee1, expression of GFP-Crk-nuc did not induce a G2/M cell cycle block or cause increased Cdc2 Tyr15 phosphorylation. Finally, upon UV stimulation, we found that endogenous Crk II translocated to the nucleus and potentiated the extent of UV-inducible apoptosis after 4 h. These data suggest that nuclear compartmentalization of Crk II antagonizes its cytoskeletal functions and assign a proapoptotic role to the nuclear pool of Crk II.
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PMID:Proapoptotic function of the nuclear Crk II adaptor protein. 1776 57

Undecylprodigiosin (UP) is a bacterial bioactive metabolite produced by Streptomyces and Serratia. In this study, we explored the anticancer effect of UP. Human breast carcinoma cell lines BT-20, MCF-7, MDA-MB-231 and T47D and one nonmalignant human breast epithelial cell line, MCF-10A, were tested in this study. We found that UP exerted a potent cytotoxicity against all breast carcinoma cell lines in a dose- and time-dependent manner. In contrast, UP showed limited toxicity to MCF-10A cells, indicating UP's cytotoxic effect is selective for malignant cells. UP's cytotoxic effect was due to apoptosis, as confirmed by positive TUNEL signals, annexin V-binding, caspase 9 activation and PARP cleavage. Notably, UP-induced apoptosis was blocked by the pan-caspase inhibitor z-VAD.fmk, further indicating the involvement of caspase activity. Moreover, UP caused a marked decrease of the levels of antiapoptotic BCL-X(L), Survivin and XIAP while enhancing the levels of proapoptotic BIK, BIM, MCL-1S and NOXA, consequently favoring induction of apoptosis. Additionally, we found that cells with functional p53 (MCF-7, T47D) or mutant p53 (BT-20, MDA-MB-231) were both susceptible to UP's cytotoxicity. Importantly, UP was able to induce apoptosis in MCF-7 cells with p53 knockdown by RNA interference, confirming the dispensability of p53 in UP-induced apoptosis. Overall, our results establish that UP induces p53-independent apoptosis in breast carcinoma cells with no marked toxicity to nonmalignant cells, raising the possibility of its use as a new chemotherapeutic drug for breast cancer irrespective of p53 status.
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PMID:Undecylprodigiosin selectively induces apoptosis in human breast carcinoma cells independent of p53. 1788 Oct 28

We devised a short-term culture system allowing us to define novel characteristics of programmed cell death (PCD) of fetal oocytes and to underscore new aspects of this process. Mouse fetal oocytes cultured in conditions allowing meiotic progression underwent apoptotic degeneration as revealed by TUNEL staining, DNA ladder, Annexin V binding, PARP cleavage and, usually, caspase activation. TEM observations show, however, recurrent atypical apoptotic morphologies characterized by the absence of chromatin margination and nuclear fragmentation; oocytes with autophagic and necrotic features are also observed. Moreover, under the fluorescence microscope a subpopulation of TUNEL(+) oocytes appear morphologically healthy and do not show detectable caspase activity. Finally, caspase inhibitors are able to slow down, but not to abolish, oocyte cell death, whereas calpain inhibitor I significantly reduces the number of TUNEL(+) oocytes after 4 days of culture, and rapamycin (mTOR inhibitor) increases such numbers both at day 3 and 4. These observations together with results showing expression in cultured oocytes undergoing cell death of apoptosis inducing factor and Beclin 1, two important players of caspase independent and autophagic cell death, respectively, demonstrate that fetal oocytes possess and are able to activate several players of various forms of cell death. However, causal correlation among different cell death pathways in such oocytes remains to be determined and stimuli causing the activation of these pathways in vitro and in vivo also clarified.
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PMID:Cell death in fetal oocytes: many players for multiple pathways. 1809 6

The cell survival activity of human glioma cells is largely dependent on autocrine fibroblast growth factor (FGF) signaling. Caspases, a family of cysteine proteases, play an integral part in the execution phase of apoptosis. To better understand the mechanism of resistance to apoptosis in human glioma cells, we investigated the effect of a blockade of endogenous FGF signaling through the expression of the dominant negative type I FGF receptor (DNFGFR) in U251MG cells. The cells were infected with adenovirus vector expressing DNFGFR (AdDNFGFR) and apoptosis was semi-quantified by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method and flow cytometric annexin V assay. The activation of caspase-3, -8, and -9, the activation of Akt, a serine/threonine protein kinase, and the cleavage of poly(ADP-ribose) polymerase (PARP) were analyzed by immunoblotting. The infection with AdDNFGFR (multiplicity of infection of 200) induced marked apoptosis, along with a down-regulation of akt phosphorylation, and activation of caspase-9 and -3, but not -8. By contrast, LacZ virus (a control) had minimal effects. The level of the cleaved form of PARP was increased in a time-dependent fashion, and this increase was inhibited by adding Z-DEVD-FMK, a caspase-3 inhibitor, and Z-LEHD-FMK, a caspase-9 inhibitor. Moreover, ultraviolet exposure (100 J/m(2)) induced apoptosis and caspase-8, but not caspase-9, activation. Our data suggested that the induction of apoptosis through the inhibition of endogenous FGF signaling is caspase-9 pathway- dependent. The suppression of this or other specific anti-apoptotic pathways may lead to genetic or pharmacological manipulations that favorably modulate the malignant behavior of human gliomas.
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PMID:Caspase-9 pathway activation by inhibiting endogenous fibroblast growth factor signaling in human glioma cells. 1820 70

It is reported that diesel exhaust particles contain more 1-nitropyrene (1-NP) than benzo[a]pyrene (B[a]P), both of which are potent carcinogenic compounds. In this study, we show that 1-NP is more potent in reducing cell viability than B[a]P, pyrene, nitrobenzene, and nitromethane. Aldo-keto reductases (AKRs) are enzymes which metabolize polycyclic aromatic hydrocarbons into active metabolites that form PAH-DNA-adducts causing mutagenesis of DNA. We found that the AKR1C2 inhibitor, ursodeoxycholic acid (UA), inhibited 1-NP-induced, but not B[a]P-induced, phosphorylation of p53 and cleavage of poly (ADP-ribose) polymerase (PARP). 1-NP-induced apoptosis was also suppressed by UA, as detected by Hoechst 33342 staining, flow cytometric analysis of subG0/G1 phase and annexin V binding to phosphatidylserine. The AKR1C1 and 1C4 inhibitor, 1,10-phenanthroline (Phen), inhibited the toxic effects of both 1-NP and B[a]P. In contrast, the AKR7A1 and 7A5 inhibitors, succinate and citrate, did not influence the toxic effects of 1-NP or B[a]P. In addition, several metabolic and signaling pathways were analyzed, these were used to compare the results of the toxic effect of AKRs on 1-NP and B[a]P. Through the application of kinase inhibitors, results indicated that p38-MAPK, but not ERK1/2 or JNK, was essential for mediating both 1-NP's and B[a]P's induction of the phosphorylation of p53 and cleavage of PARP. Neither ellipticine, a CYP1A1 inhibitor, nor 2,6-diisopropylphenol, a CYP1A2 and 2B1 inhibitor, blocked the toxic effects of 1-NP and B[a]P, which indicates that neither CYP1A1, 1A2, nor 2B1 is essential for the transformation of 1-NP and B[a], into toxic metabolites. AKR1C2 was constitutively expressed in HepG2 cells and was not regulated by 1-NP or B[a]P. In conclusion, this is the first report on AKRs' actions toward nitro-PAH in cells. The metabolic and signaling pathways for the toxic effects of both 1-NP and B[a]P are similar except that AKR1C2 plays differential role between them. The results provide valuable information for further investigations on AKRs.
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PMID:Aldo-keto reductase 1C2 is essential for 1-nitropyrene's but not for benzo[a]pyrene's induction of p53 phosphorylation and apoptosis. 1820

Interferons (IFNs) are pleiotropic cytokines responsible for inducing innate and adaptive immunities against a wide range of viruses and other microbial pathogens. In addition, IFNs also exert antitumor activities due to their antiproliferative, immunomodulatory, proapoptotic functions. In the last decades, the successful clinical application of IFNs for treatment of cancer, particularly leukemia, has improved the quality and longevity of life for many patients. The induction of tumor cell apoptosis by IFNs is believed to contribute, at least in part, to the beneficial effects. IFN subtypes, such as IFN-alpha, IFN-beta, and IFN-gamma, induce apoptosis through cell type-specific signaling pathways, and several putative IFN-stimulated genes (ISGs) with proapoptotic functions have been identified. Here, we analyzed the ability of IFN-alpha, IFN-beta, or IFN-gamma to induce apoptosis in several malignant hematologic cell lines. We found that treatment with IFN-gamma, but not IFN-alpha, or IFN-beta, specifically induces HL-60 leukemia cells to undergo apoptosis. Roughly 30% of HL-60 cells treated for 48 h with IFN-gamma, but not IFN-gamma, or IFN-beta, underwent apoptosis as monitored by annexin V labeling to determine changes in phosphatidylserine (PS) asymmetry and TUNEL assay to detect DNA fragmentation. Consistent with these results, treatment with IFN-gamma, but not IFN-alpha or IFN-beta, induced the release of cytochrome c, activation of caspase-3, and cleavage of poly (ADP-ribose) polymerase (PARP), a well-characterized caspase-3 substrate. Further investigation into the potential mechanism responsible for mitochondrial disruption revealed that treatment with IFN-gamma caused decreased levels of Bcl-2 and increased levels of Bak. This study thus provides the basis for additional research to uncover the molecular mechanism by which IFN-gamma regulates the expression of Bcl-2 family members in various cell types.
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PMID:IFN-gamma induces apoptosis in HL-60 cells through decreased Bcl-2 and increased Bak expression. 1827 2

Platycodin D (PD), a major constituent of triterpene saponins in Platycodon grandiflorum, has also become an interesting candidate for cancer chemotherapy; however, little is known about apoptotic mechanisms on cancer cells. We herein investigated the mechanisms that are related to PD-induced antiproliferation and cell death in human leukemia cells (U937, THP-1 and K562 cells). Cell growth was assessed with proliferation assays, cell counting, flow cytometry, phase contrast microscopy and Western blot assay. Microtubule (MT) formation was measured with immunofluorescent staining and in vitro tubulin polymerization assay. Apoptotic effect was analyzed by assessing increase in annexin V-staining and caspase-3 activity. Treatment of synchronized leukemia cells with varying concentrations of PD resulted in significant mitotic arrest and endoreduplication (END) via downregulation of Cdc2/cyclin B1 and upregulation of wee1 expression, and elevated the Cdk2 protein via downregulation of p21 within 48 hr. We also researched PD's induction of polyploidy through the MT polymerization. Immunofluorescent microscopy and Western blot analysis revealed that PD significantly caused MT polymerization in leukemia cells. We also found that very high concentrations of PD (>200 microM) were required to directly induce MT polymerization in vitro. Finally, PD exposure induced apoptosis in U937 cells through caspase-3-dependent PARP and lamin A cleavage. We conclude that the primary antileukemia activity of PD is induction of endoreduplication and mitotic arrest, as a consequence of suppressing spindle MT dynamics and in promoting apoptosis in human leukemia cells.
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PMID:Platycodin D induces mitotic arrest in vitro, leading to endoreduplication, inhibition of proliferation and apoptosis in leukemia cells. 1835 45

Treatment of pancreatic acinar cells by hydrogen sulphide has been shown to induce apoptosis. However, a potential role of mitogen-activated protein kinases (MAPKs) in this apoptotic pathway remains unknown. The present study examined the role of MAPKs in H(2)S-induced apoptosis in mouse pancreatic acinar cells. Pancreatic acinar cells were treated with 10 microM NaHS (a donor of H(2)S) for 3 hrs. For the evaluation of the role of MAPKs, PD98059, SP600125 and SB203580 were used as MAPKs inhibitors for ERK1/2, JNK1/2 and p38 MAPK, respectively. We observed activation of ERK1/2, JNK1/2 and p38 when pancreatic acini were exposed to H(2)S. Moreover, H(2)S-induced ERK1/2, JNK1/2 and p38 activation were blocked by pre-treatment with their corresponding inhibitor in a dose-dependent manner. H(2)S-induced apoptosis led to an increase in caspase 3 activity and this activity was attenuated when caspase 3 inhibitor were used. Also, the cleavage of caspase 3 correlated with that of poly-(ADP-ribose)-polymerase (PARP) cleavage. H(2)S treatment induced the release of cytochrome c, smac from mitochondria into the cytoplasm, translocation of Bax into mitochondria and decreased the protein level of Bcl-2. Inhibition of ERK1/2 using PD98059 caused further enhancement of apoptosis as evidenced by annexin V staining, while SP600125 and SB203580 abrogated H(2)S-induced apoptosis. Taken together, the data suggest that activation of ERKs promotes cell survival, whereas activation of JNKs and p38 MAP kinase leads to H(2)S-induced apoptosis.
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PMID:H2S-induced pancreatic acinar cell apoptosis is mediated via JNK and p38 MAP kinase. 1837 39

Combined treatment with quercetin and TRAIL induced cytotoxicity and enhanced annexin V staining and poly (ADP-ribose) polymerase (PARP) cleavage in human prostate cancer cell lines DU-145 and PC-3. These indicators of apoptosis resulted from the activation of caspase-8, -9, and -3. Although the expression levels of FLIPs, cIAP1, cIAP2, and the Bcl-2 family were not changed in quercetin-treated cells, significant downregulation of survivin occurred. Knockdown survivin by siRNA significantly increased TRAIL-induced apoptosis. We hypothesized that quercetin-induced activation of MAPK (ERK, p38, JNK) is responsible for downregulation of survivin gene expression. To test this hypothesis, we selectively inhibited MAPK during treatment with quercetin. Our data demonstrated that inhibitor of ERK (PD98059), but not p38 MAPK (SB203580) or JNK (SP600125), significantly maintained the intracellular level of survivin during treatment with quercetin. Interestingly, PD98059 also prevented quercetin-induced deacetylation of histone H3. Data from survivin promoter activity assay suggest that the Sp1 transcription factor binds to the survivin promoter region and quercetin inhibits its binding activity through deacetylation of histone H3. Quercetin-induced activation of the ERK-MSK1 signal transduction pathway may be responsible for deacetylation of histone H3. Taken together, our findings suggest that quercetin enhances TRAIL induced apoptosis by inhibition of survivin expression, through ERK-MSK1-mediated deacetylation of H3.
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PMID:Quercetin augments TRAIL-induced apoptotic death: involvement of the ERK signal transduction pathway. 1837 72

The cell proliferation of p53-deficient Jurkat T cells is controlled after prolonged exposure to human lactoferrin (Lf). However, the molecular mechanism by which Lf influences these cellular responses remains unclear. In this study, we demonstrate that Lf-induced apoptosis in Jurkat T cells occurs in a dose- and time-dependent manner via the regulation of c-Jun N-terminal kinase (JNK) activity. Jurkat cells exposed to Lf for 1 day, especially at concentrations in excess of 500 microg/ml, showed typical apoptosis, as indicated by decreased cell viability and increased Annexin V binding. Our results also showed that Lf induced the activation of caspase 9 and caspase 3 activation, as demonstrated by our detection of cleaved caspases and PARP. Lf-induced apoptosis did not influence Bcl-2 expression via an ERK1/2 phosphorylation pathway, but was rather associated with the level of Bcl-2 phosphorylation. The treatment of cells with the specific JNK inhibitor SP600125, but not the p38 MAPK inhibitor SB203580, revealed that the JNK-Bcl-2 signaling cascade is required for Lf-induced apoptosis. When JNK activation was abolished by SP600125, no Bcl-2 phosphorylation was detected, and the Lf-treated Jurkat cells did not undergo cell death. These findings indicate that Lf functions as a biological mediator of apoptosis in the human leukemia Jurkat T-cell line, via the JNK-associated Bcl-2 signaling pathway.
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PMID:Requirement of the JNK-associated Bcl-2 pathway for human lactoferrin-induced apoptosis in the Jurkat leukemia T cell line. 1853 98


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