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:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although pectenotoxin-2 (PTX-2) is known to modify the actin cytoskeleton, very little is known about its apoptosis mechanism. In this study, we investigated whether PTX-2 induces apoptotic effects through suppression of the NF-kappaB signaling pathway in several leukemia cell types. PTX-2 significantly induced growth inhibition and apoptosis in a dose-dependent manner. Treatment with PTX-2 also significantly increased caspase-3 activity and poly (ADP-ribose) polymerase (PARP) cleavage, however caspase-3 inhibitor z-DEVD-fmk significantly inhibited PTX-2-induced cell death. These data suggest that the activation of caspase-3 is associated with PTX-2-induced apoptosis. NF-kappaB has also been shown to inhibit apoptosis in response to chemotherapeutic agents. As examined by the DNA-binding of NF-kappaB activation, we found that PTX-2 suppressed constitutive NF-kappaB activation and determined by p65 and p50 nuclear translocation, and IkappaBalpha degradation through dephosphorylation of Akt. Attenuation of constitutive NF-kappaB activity by pretreatment with pyrrolidine dithiocarbamate (PDTC), an NF-kappaB nuclear translocation inhibitor, induced significantly apoptosis in the presence of PTX-2. In addition, treatment of PTX-2 down-regulated NF-kappaB-dependent gene expression, Cox-2, IAP-1, IAP-2 and XIAP, at the transcriptional and translational level. Taken together, these results suggest that anti-cancer activities induced by PTX-2 may be mediated in part through suppression of constitutive NF-kappaB activity.
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PMID:Pectenotoxin-2 abolishes constitutively activated NF-kappaB, leading to suppression of NF-kappaB related gene products and potentiation of apoptosis. 1860 10

XIAP (X chromosome-linked inhibitor of apoptosis) is a member of the anti-apoptotic IAP gene family and an inhibitor of caspase-3. We show here that loss of XIAP renders cells highly sensitive to oxidative stress. Stimulation of XIAP(-/-) MEF with hydrogen peroxide, or other agents that generate reactive oxygen species (ROS) results in increased apoptosis assessed by caspase-3 activity and PARP cleavage. Furthermore, we observed increased levels of ROS and diminished expression of antioxidative genes, e.g., SOD1, -2, NQO1, HO-1, and Txn2 in XIAP(-/-) cells. In addition, stimulation of XIAP(-/-) MEF with hydrogen peroxide resulted in enhanced phosphorylation of JNK. Our findings reveal that XIAP, in addition to its well described caspase-inhibitory function, prevents prolonged JNK activation and is critically involved in modulating ROS levels through regulation of antioxidative genes, thereby inhibiting ROS-induced apoptosis.
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PMID:XIAP regulates intracellular ROS by enhancing antioxidant gene expression. 1869 82

CDA-II (cell differentiation agent II) was a urinary preparation, isolated from healthy human urine. We determined the anticancer activity of CDA-II using human acute myeloid leukemia (AML) cell lines, K562, Kasumi-1 and KG-1. An in vitro cytotoxicity assay showed that CDA-II exhibited growth arrest in leukemic cells, while it did not induce cytotoxicity in normal peripheral blood mononuclear cells (PBMCs). In vivo studies using the Kasumi-1 xenografted SCID mouse model showed tumor inhibition rate were increased and the survival time were prolonged in a dose-dependent manner, without any significant toxicity on mice body. Depolarized mitochondrial membranes and the activation of caspase-3, 9 as well as PARP were found in leukemic cells treated with CDA-II for 6-24h. We further found NF-kappaB nuclear translocation were prevented by CDA-II treatment, which therefore inactivated NF-kappaB and down-regulated its target genes expression, including Bcl-2/Bax ratio, Mcl-1 and XIAP. The caspase-3 inhibitor Z-DEVD-FMK inhibited CDA-II-induced apoptosis and CDA-II combined with NF-kappaB inhibitor PDTC significantly increased the apoptotic rate of leukemic cells. We concluded that CDA-II potently induced caspase-dependent leukemia-specific apoptosis in leukemic cells mediated through inactivation of NF-kappaB, involving in Bcl-2 family and XIAP, which has no cytotoxicity on normal cells.
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PMID:CDA-II, a urinary preparation, induces growth arrest and apoptosis of human leukemia cells through inactivation of nuclear factor-kappaB in a caspase-dependent manner. 1876 Oct 50

Recent reports implicate poly(ADP-ribose) polymerase-1 (PARP-1) in the activation of nuclear factor kappaB (NF-kappaB). We investigated the role of PARP-1 in the NF-kappaB signalling cascade induced by ionizing radiation (IR). AG14361, a potent PARP-1 inhibitor, was used in two breast cancer cell lines expressing different levels of constitutively activated NF-kappaB, as well as mouse embryonic fibroblasts (MEFs) proficient or deficient for PARP-1 or NF-kappaB p65. In the breast cancer cell lines, AG14361 had no effect on IR-induced degradation of IkappaBalpha or nuclear translocation of p50 or p65. However, AG14361 inhibited IR-induced NF-kappaB-dependent transcription of a luciferase reporter gene. Similarly, in PARP-1(-/-) MEFs, IR-induced nuclear translocation of p50 and p65 was normal, but kappaB binding and transcriptional activation did not occur. AG14361 sensitized both breast cancer cell lines to IR-induced cell killing, inhibited IR-induced XIAP expression and increased caspase-3 activity. However, AG14361 failed to increase IR-induced caspase activity when p65 was knocked down by siRNA. Consistent with this, AG14361 sensitized p65(+/+) but not p65(-/-) MEFs to IR. We conclude that PARP-1 activity is essential in the upstream regulation of IR-induced NF-kappaB activation. These data indicate that potentiation of IR-induced cytotoxicity by AG14361 is mediated solely by inhibition of NF-kappaB activation.
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PMID:Ionizing radiation-induced NF-kappaB activation requires PARP-1 function to confer radioresistance. 1906 Sep 26

Although isothiocyanates have been shown to inhibit carcinogen-induced tumorigenesis, no studies have been made to determine their therapeutic potential for the treatment of breast cancer. In the present study, we evaluated the apoptotic activities of phenethyl isothiocyanate (PEITC) in human breast cancer MCF-7 cells. Exposure to PEITC potently reduced cell viability. In addition, DNA fragments and TUNEL positive nuclei were detected in PEITC-treated cells. Furthermore, PEITC induced apoptosis via activation of caspases 7 and 9 and the cleavage of PARP, and these effects were reversed by treatment with the caspase inhibitor, Z-VAD-fmk. PEITC also caused a decrease in the levels of Bcl-2 with a concomitant increase in Bax levels, which resulted in the release of cytochrome c. XIAP suppression and Smac translocation also contributed to the PEITC-induced apoptosis. However, PEITC did not increase the expressions of p53 and p21. Taken together, the results of this study demonstrate that PEITC significantly induces apoptosis via a mitochondrial pathway. Specifically, PEITC induced a change in the Bax/Bcl-2 ratios, XIAP levels and Smac translocation that was conjunction with the release of cytochrome c and following caspase activation. Therefore, PEITC has the potential for use as a therapeutic agent for the treatment of breast cancer.
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PMID:Phenethyl isothiocyanate induced apoptosis via down regulation of Bcl-2/XIAP and triggering of the mitochondrial pathway in MCF-7 cells. 1909 31

Traumatic, infectious, metabolic, and chemical noxa to the nervous system are the etiology of a crippling disease generally termed neuropathy. Motor disorders, altered sensibility, and pain are the pathognomonic traits. Cellular alterations induced by this chronic pathology include mitochondrial dysfunctions that lead to the activation of the apoptotic cascade. Energy imbalance can compromise the maintenance of mitochondrial membrane potential, furthering the release of cytochrome C and the subsequent cleavage and activation of caspases. Chronic constriction injury (CCI) of the rat sciatic nerve is a neuropathy model able to induce a strong mitochondrial impairment with a consequent apoptotic induction. In this model, the acetylcholinesterase inhibitor physostigmine is administered at 0.125 mg/kg i.p. (twice per day) starting from the operation and for 15 days after. The cholinergic activation reduces cytosolic levels of cytochrome C, suggesting an improved stability of the mitochondrial membrane, and the expression level of the active caspase 3 fragments (19, 16 kDa) is reduced significantly with respect to saline treatment. Accordingly, physostigmine impairs caspase 3 protease activity. In fact, the target of the activated caspase 3, the 89-kDa PARP fragment, is significantly less expressed in the ligated nerve of physostigmine-treated rats, reaching levels that are comparable to those in the contralateral unligated nerve. Finally, this natural acetylcholinesterase inhibitor reduces DNA fragmentation both in the proximal and in the distal parts of the nerve. This protection correlates with the induction of XIAP. Therefore, apoptosis, central to tissue degeneration, is prevented by repeated physostigmine treatment of CCI animals.
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PMID:Neuropathy-induced apoptosis: protective effect of physostigmine. 1917 Jan 87

Pituitary adenomas, which account for 15-20% of intracranial tumors, are associated with significant morbidity and mortality, due in part, to hormone hypersecretion and mass effects following increased proliferation. Radiotherapy and surgery remain frontline treatment options; however, adverse side effects and surgical limitations to treat invasive tumors necessitate the need for novel therapeutic targets. This study tested the efficacy of the histone deacetylase inhibitor (HDACi), suberoylanilide hydroxamic acid (SAHA) in GH3, and MMQ pituitary adenoma cells. Clinically achievable concentrations of SAHA (500 nM-4 microM) induced growth arrest and increased cell death in GH3 pituitary adenoma cells. Further investigation into the mechanism of cell death revealed an increase in PARP cleavage and procaspase-3 activation, consistent with apoptotic cell death. SAHA also attenuated the expression of anti-apoptotic IAP (XIAP, survivin) and Bcl-2 family proteins (Bcl-2, Bcl-xL), but did not alter Bax expression. Together, these findings support a possible utility for SAHA alone or in combination with radiation for the treatment of pituitary adenoma.
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PMID:Suberoylanilide hydroxamic acid (SAHA) induces growth arrest and apoptosis in pituitary adenoma cells. 1929 26

Cardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. CTX III-induced apoptosis in human breast MCF-7 cancer cells was confirmed by sub-G1 formation, phosphatidylserine (PS) externalization, and poly (ADP-ribose) polymerase (PARP) cleavage with an IC50 of 2 microg/ml at 48 h. Effects of CTX III on proliferation and apoptosis correlated with upregulation of Bax, and downregulation of Bcl-XL, Bcl-2, and XIAP, with no appreciable alteration on the protein levels of Bid, Bim, and survivin. CTX III treatment also caused release of mitochondrial cytochrome c to the cytosol, which led to subsequent activation of capase-9. Moreover, CTX III inhibited the nuclear factor-kappaB (NF-kappaB) activation through inhibition of IkappaB kinase (IkappaK) activity. Overall, our results indicate that CTX III downregulates NF-kappaB in MCF-7 cells, leading to the suppression of proliferation and induction of apoptosis. These findings suggest the molecular basis for CTX III-induced apoptotic death of MCF-7 cells.
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PMID:Effects of cardiotoxin III on NF-kappaB function, proliferation, and apoptosis in human breast MCF-7 cancer cells. 1940 76

Physalis peruviana L. (PP) is a popular folk medicine used for treating cancer, leukemia, hepatitis, rheumatism and other diseases. In this study, our objectives were to examine the total flavonoid and phenol content of different PP extracts (aqueous: HWEPP; ethanolic: EEPP; supercritical carbon dioxide: SCEPP-0, SCEPP-4 and SCEPP-5) and their antiproliferative effects in human lung cancer H661 cells. Among all the extracts tested, results showed that SCEPP-5 possessed the highest total flavonoid (226.19 +/- 4.15 mg/g) and phenol (100.82 +/- 6.25 mg/g) contents. SCEPP-5 also demonstrated the most potent inhibitory effect on H661 cell proliferation. Using DNA ladder and flow cytometry analysis, SCEPP-5 effectively induced H661 cell apoptosis as demonstrated by the accumulation of Sub-G1 peak and fragmentation of DNA. SCEPP-5 not only induced cell cycle arrest at S phase, it also up-regulated the expression of pro-apoptotic protein (Bax) and down-regulated the inhibitor of apoptosis protein (IAP). Furthermore, the apoptotic induction in H661 cells was found to associate with an elevated p53 protein expression, cytochrome c release, caspase-3 activation and PARP cleavage. Taken together, these results conclude that SCEPP-5 induced cell cycle arrest at S phase, and its apoptotic induction could be mediated through the p53-dependent pathway and modification of Bax and XIAP proteins expression. The results have also provided important pharmacological backgrounds for the potential use of PP supercritical fluid extract as products for cancer prevention.
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PMID:Supercritical carbon dioxide extract of Physalis peruviana induced cell cycle arrest and apoptosis in human lung cancer H661 cells. 1942 86

Cisplatin is a first-line chemotherapeutic agent and a powerful component of standard treatment regimens for several human malignancies including bladder cancer. DNA-Pt adducts produced by cisplatin are mainly responsible for cellular toxicity and induction of apoptosis. Identification of the mechanisms that control sensitivity to cisplatin is central to improving its therapeutic index and to successfully encountering the acquired resistance frequently emerging during therapy. In the present study, using MTT-based assays, Western blotting and semi-quantitative RT-PCR, we examined the apoptosis-related cellular responses to cisplatin exposure in two human urinary bladder cancer cell lines characterized by different malignancy grade and p53 genetic status. Both RT4 (grade I; wild-type p53) and T24 (grade III; mutant p53) cell types proved to be vulnerable to cisplatin apoptotic activity, albeit in a grade-dependent and drug dose-specific manner, as demonstrated by the proteolytic processing profiles of Caspase-8, Caspase-9, Caspase-3, and the Caspase repertoire characteristic substrates PARP and Lamin A/C, as well. The differential resistance of RT4 and T24 cells to cisplatin-induced apoptosis was associated with an RT4-specific phosphorylation (Ser15; Ser392) pattern of p53, together with structural amputations of the Akt and XIAP anti-apoptotic regulators. Furthermore, cisplatin administration resulted in a Granzyme B-mediated proteolytic cleavage of Hsp90 molecular chaperone, exclusively occurring in RT4 cells. To generate functional networks, expression analysis of a number of genes, including Bik, Bim, Bcl-2, FAP-1, Fas, FasL, TRAIL, Puma, Caspase-10, ATP7A, ATP7B and MRP1, was performed, strongly supporting the role of p53-dependent and p53-independent transcriptional responses in cisplatin-induced apoptosis of bladder cancer cells.
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PMID:Human bladder cancer cells undergo cisplatin-induced apoptosis that is associated with p53-dependent and p53-independent responses. 1957 56


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