Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The luteal phase in the normal human menstrual cycle is known to be about 14 days. The physiological mechanisms that regulate the corpus luteum remain to be clarified, although apoptosis is reported to be involved. This study was undertaken to investigate the regulation of luteal function by gonadotropins, cytokines, and PGs, concentrating attention on the incidence of apoptosis and its molecular mechanisms in cultured human luteinized granulosa cells collected at oocyte pick-up from patients undergoing in vitro fertilization and embryo transfer. Clusters of granulosa cells were pipetted in 0.1% hyaluronidase in phosphate-buffered saline. After cell separation by centrifugation using Ficoll-Paque, 1 x 104 viable cells/mL in RPMI 1640 medium with 10% FCS were used for experimentation. Substances added were FSH (100 ng/mL), hCG (100 ng/mL), LH (100 ng/mL), interleukin-1beta (IL-1beta; 10 ng/mL), transforming growth factor-beta1 (TGFbeta1; 10 ng/mL), macrophage colony-stimulating factor (MCSF; 10 ng/mL), tumor necrosis factor-alpha (TNFalpha; 10 ng/mL), and PGF2alpha (10 ng/mL). After 24-h culture at 37 C under 5% CO2 and air, cells were fixed with 4% neutral buffered formalin and stained with Hoechst 33258. Apoptotic bodies were counted under a fluorescence microscope, and immunostaining was performed using anti-Fas, Fas ligand, Bcl-2, Bax, and p53 antibodies. Incidences of apoptotic bodies in the group without substance addition were 0.7 +/- 0.2% (0 h), 5.9 +/-0.6% (24 h), and 7.9 +/- 1.2% (48 h); spontaneous increase was significant at the latter time points. Defining the incidence at 24 h as 100%, values after treatment were: FSH, 57%; LH, 84%; hCG, 44%; IL-1beta, 76%; TGFbeta1, 52%; M-CSF, 50%; TNFalpha, 177%; and PGF2alpha, 147%. Significant suppression was observed with FSH, hCG, TGFbeta1, and M-CSF (P < 0.01). On the other hand, significant induction occurred with TNFalpha and PGF2alpha (P < 0.01). On immunostaining, the incidence of stained cells with anti-Fas, Fas ligand, Bax, and p53 antibody was increased after 24-h incubation without addition. This was reduced by hCG, TGFbeta1, and M-CSF. No stained cells were observed with anti-Bcl-2 antibody before or after incubation. In conclusion, our results suggest that both gonadotropins (FSH and hCG) and cytokines (TGFbeta1 and M-CSF) may be involved in the support of luteal function via suppression of apoptosis, and that TNFalpha and PGF2alpha may contribute to ovarian dysfunction and/or luteal regression via its induction in human luteinized granulosa cells. Our results also suggest that Fas, Fas ligand, p53, and Bax may play roles in this apoptosis controlled by hCG, TGFbeta1, and M-CSF.
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PMID:Gonadotropins and cytokines affect luteal function through control of apoptosis in human luteinized granulosa cells. 1077 Feb 7

KILLER/DR5, a tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor gene, has been shown to be induced by DNA damaging agents and radiation in a p53-dependent manner. Although TRAIL is a potential therapeutic agent for cancer, the induction mechanism of its receptors is poorly understood. Here we show the identification of three p53 DNA-binding sites in the KILLER/DR5 genomic locus located upstream (BS1; -0.82 Kb) of the ATG site, within Intron 1 (BS2; +0.25 Kb downstream of the ATG) and within Intron 2 (BS3; +1.25 Kb downstream of the ATG). A modified p53-binding and immunoselection protocol using a wild-type p53-expressing adenovirus vector (Ad-p53) was used to identify the binding sites and to show that each binding site can bind specifically to wild-type p53 protein (wt-p53). A reporter assay revealed that only BS2 could enhance luciferase expression driven by a basal promoter. We constructed a reporter plasmid carrying the genomic regulatory region of KILLER/DR5 including the three p53 DNA-binding sites but no additional basal promoter. The genomic fragment showed basal transcriptional activity which was induced by wt-p53 but not by mutant p53, and human papilloma virus E6 inhibited the p53-dependent activation. Mutation of BS2 abrogated not only the binding activity of wt-p53 but also the induction of the KILLER/DR5 genomic promoter-reporter gene, indicating that BS2 is responsible for the p53-dependent transactivation of KILLER/ DR5. In p53-wild-type but not -mutant or -null cell lines, doxorubicin treatment stabilized p53 protein, and increased specific binding to BS2 as revealed by EMSA, and upregulated the KILLER/DR5 promoter-luciferase reporter gene. These results suggest that the transactivation of KILLER/DR5 is directly regulated by exogenous or endogenous wt-p53 and establishes KILLER/DR5 as a p53 target gene that can signal apoptotic death.
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PMID:Wild-type p53 transactivates the KILLER/DR5 gene through an intronic sequence-specific DNA-binding site. 1077 7

By studying the hibernation in ground squirrels, a protein factor termed hibernation induction trigger (HIT) was found to induce hibernation in summer-active ground squirrels. Further purification of HIT yielded an 88-kD peptide that is enriched in winter hibernator. Partial sequence of the 88-kD protein indicates that it may be related to the inhibitor of metalloproteinase. Delta opioid [D-Ala(2),D-Leu(5)]enkephalin (DADLE) also induced hibernation. HIT and DADLE were found to prolong survival of peripheral organs preserved en bloc or as a single preparation. These organs include the lung, the heart, liver and kidney. DADLE also promotes survival of neurons in the central nervous system. Methamphetamine (METH) is known to cause destruction of dopaminergic (DA) terminals in the brain. DADLE blocked and reversed the DA terminal damage induced by METH. DADLE acted against this effect of METH at least in part by attenuating the mRNA expressions of a tumor necrosis factor p53 and an immediate early gene c-fos. DADLE also blocked the neuronal damage induced by ischemia-reperfusion following a transient middle cerebral artery occlusion. In PC12 cells, DADLE blocked the cell death caused by serum deprivation in a naltrexone-sensitive manner. Thus, DADLE, and by extension the endogenous delta opioid peptides and delta opioid receptors, may play an important role in organ and neuronal survival. Here, critical developments concerning these fascinating cell protective properties of DADLE are reviewed.
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PMID:Delta opioid peptide[D- Ala(2),D-Leu(5)]enkephalin promotes cell survival. 1081 Feb 37

This article reviews advances in the study of the molecular mechanisms for ultraviolet (UV)-induced keratinocyte apoptosis, with particular reference to the cytokines tumor necrosis factor-alpha (TNF-alpha) and Fas ligand (FasL). TNF-alpha and FasL induce their respective receptors and then activate caspase enzymes that are critically involved in the apoptotic process. This activation is further amplified by intracellular mitochondria-associated mechanisms. Using gene-targeted knockout mice lacking either the TNF-Rp55 or the TNF-Rp75, we have shown that TNF-alpha plays an important role in UV-induced keratinocyte apoptosis via TNF-Rp55. TNF-Rp55 shares homology with Fas and contains an intracellular death domain. UV seems to directly stimulate cross-linking of Fas, resulting in the engagement of the death machinery. Fas-associated death domain protein (FADD) acts as an adapter protein in both the TNF-Rp55 and Fas death-inducing cascades and is responsible for downstream signal transduction by recruiting caspases. Moreover, signaling of p53 contributes to the induction of apoptosis by regulating Bcl-2 family expression and increasing surface Fas expression. In addition to induction mechanisms of apoptosis, there are numerous inhibitory molecules that play a role in restricting the apoptotic pathway. Thus, the ultimate determination of whether or not a cell undergoes apoptosis after UV radiation is based on the balance between agonist and antagonist pathways.
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PMID:Molecular mechanism of ultraviolet-induced keratinocyte apoptosis. 1084 Oct 72

The deleterious effects of lipopolysaccharide (LPS) during endotoxic shock are associated with the secretion of tumor necrosis factor (TNF) and the production of nitric oxide (NO), both predominantly released by tissue macrophages. We analyzed the mechanism by which LPS induces apoptosis in bone marrow-derived macrophages (BMDM). LPS-induced apoptosis reached a plateau at about 6 hours of stimulation, whereas the production of NO by the inducible NO-synthase (iNOS) required between 12 and 24 hours. Furthermore, LPS-induced early apoptosis was only moderately reduced in the presence of an inhibitor of iNOS or when using macrophages from iNOS -/-mice. In contrast, early apoptosis was paralleled by the rapid secretion of TNF and was almost absent in macrophages from mice deficient for one (p55) or both (p55 and p75) TNF-receptors. During the late phase of apoptosis (12-24 hours) NO significantly contributed to the death of macrophages even in the absence of TNF-receptor signaling. NO-mediated cell death, but not apoptosis induced by TNF, correlated with the induction of p53 and Bax genes. Thus, LPS-induced apoptosis results from 2 independent mechanisms: first and predominantly, through the autocrine secretion of TNF-alpha (early apoptotic events), and second, through the production of NO (late phase of apoptosis). (Blood. 2000;95:3823-3831)
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PMID:LPS induces apoptosis in macrophages mostly through the autocrine production of TNF-alpha. 1084 16

Mycobacterium tuberculosis-induced macrophage apoptosis can be inhibited by mannosylated lipoarabinomannan (ManLAM), although it induces tumor necrosis factor (TNF)-alpha and NO production, which participate in apoptosis induction. ManLAM also modulates Ca(+2)-dependent intracellular events, and Ca(+2) participates in apoptosis in different systems. Ca(+2) was assessed for involvement in M. tuberculosis-induced macrophage apoptosis and for modulation by ManLAM. The role of Ca(+2) was supported by the blockade of apoptosis by cAMP inhibitors and the Ca(+2) chelator, BAPTA/AM. These agents also inhibited caspase-1 activation and cAMP-responsive element-binding protein translocation without affecting TNF-alpha production. Infection of macrophages with M. tuberculosis induced an influx of Ca(+2) that was prevented by ManLAM. Similarly, M. tuberculosis infection-altered mitochondrial permeability transition was prevented by ManLAM and BAPTA/AM. Finally, ManLAM and BAPTA/AM reversed the effects of M. tuberculosis on p53 and Bcl-2 expression. ManLAM counteracts the alterations of calcium-dependent intracellular events that occur during M. tuberculosis-induced macrophage apoptosis.
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PMID:Mannosylated lipoarabinomannan antagonizes Mycobacterium tuberculosis-induced macrophage apoptosis by altering Ca+2-dependent cell signaling. 1088 3

LIGHT is a member of the tumor necrosis factor superfamily and is the ligand for LT-betaR, HVEM, and decoy receptor 3. LIGHT has a cytotoxic effect, which is further enhanced by the presence of interferon-gamma (IFN-gamma). Although LIGHT/IFN-gamma can activate caspase activity, neither benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone nor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone can completely inhibit LIGHT/IFN-gamma-mediated apoptosis. Moreover, overexpression of Bcl-2 further enhances LIGHT/IFN-gamma-mediated apoptosis. It appears that LIGHT and IFN-gamma act synergistically to activate caspase-3, with the resultant cleavage of Bcl-2, removal of the BH4 domain, leading to conversion of Bcl-2 from an antiapoptotic to a proapoptotic form in p53-deficient hepatocellular carcinoma Hep3BT2 cells. Thus, LIGHT seems to be able to override the protective effect of Bcl-2 and induce cell death. Although benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone and benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone can prevent the cleavage of Bcl-2 by LIGHT/IFN-gamma, they only partially inhibit apoptosis in Hep3BT2 cells that are overexpressing Bcl-2. In contrast, both LIGHT/IFN-gamma-mediated apoptosis and Bcl-2 cleavage are inhibited by free radical scavengers, indicating that free radicals may play an essential role in LIGHT/IFN-gamma-mediated apoptosis at a step upstream of caspase-3 activation. These results suggest that LIGHT signaling may diverge into multiple, separate processes.
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PMID:Overexpression of bcl-2 enhances LIGHT- and interferon-gamma -mediated apoptosis in Hep3BT2 cells. 1099 81

Due to its critical involvement in cell cycle control and apoptotic signaling, the transcription factor p53 has become the most important tumor suppressor currently under investigation. TP53 is the most frequently mutated gene in human cancers and is thought to play a crucial role in malignant transformation. Therefore, p53 appears to be an appealing target for gene therapy. Adenoviral-based p53 gene transfection is now being introduced in large clinical trials. Viral cell entry was found to be the rate-limiting step of gene delivery and thus of therapeutic efficiency. Attachment of adenoviruses to the target cell surface is mediated through the coxsackie-adenovirus receptor, and internalization is achieved via interactions with integrins of the alpha v beta(3) and alpha v beta(5) class. The assumption that the restitution of the p53-dependent apoptotic pathway results in a higher responsiveness of solid tumors to cytostatic agents remains a major matter of debate. Combinations of p53-based gene therapy with other components involved in apoptosis, such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/APO2L, or agents neutralizing tumor-promoting antiapoptotic signals, such as humanized anti-growth factor antibodies, should further improve the effectiveness of cancer treatment in the future.
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PMID:New insights into p53 regulation and gene therapy for cancer. 1100 53

Apoptosis of arterial cells induced by oxidized low density lipoproteins (OxLDL) is thought to contribute to the progression of atherosclerosis. However, most data on apoptotic effects and mechanisms of OxLDL were obtained with extensively oxidized LDL unlikely to occur in early stages of atherosclerotic lesions. We now demonstrate that mildly oxidized LDL generated by incubation with oxygen radical-producing xanthine/xanthine oxidase (X/XO) induces apoptosis in primary cultures of human coronary endothelial and SMC, as determined by TUNEL technique, DNA laddering, and FACS analysis. Apoptosis was markedly reduced when X/XO-LDL was generated in the presence of different oxygen radical scavengers. Apoptotic signals were mediated by intramembrane domains of both Fas and tumor necrosis factor (TNF) receptors I and II. Blocking of Fas ligand (FasL) reduced apoptosis by 50% and simultaneous blocking of FasL and TNF receptors by 70%. Activation of apoptotic receptors was accompanied by an increase of proapoptotic and a decrease in antiapoptotic proteins of the Bcl-2 family and resulted in marked activation of class I and II caspases. Mildly oxidized LDL also activated MAP and Jun kinases and increased p53 and other transcription factors (ATF-2, ELK-1, CREB, AP-1). Inhibitors of Map and Jun kinase significantly reduced apoptosis. Our results provide the first evidence that OxLDL-induced apoptosis involves TNF receptors and Jun activation. More important, they demonstrate that even mildly oxidized LDL formed in atherosclerotic lesions may activate a broad cascade of oxygen radical-sensitive signaling pathways affecting apoptosis and other processes influencing the evolution of plaques. Thus, we suggest that extensive oxidative modifications of LDL are not necessary to influence signal transduction and transcription in vivo.
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PMID:Mildly oxidized low density lipoprotein activates multiple apoptotic signaling pathways in human coronary cells. 1102 84

Triptolide (PG490), a diterpene triepoxide, is a potent immunosuppressive agent extracted from the Chinese herb Tripterygium wilfordii. We have previously shown that triptolide blocks NF-kappaB activation and sensitizes tumor necrosis factor (TNF-alpha)-resistant tumor cell lines to TNF-alpha-induced apoptosis. We show here that triptolide enhances chemotherapy-induced apoptosis. In triptolide-treated cells, the expression of p53 increased but the transcriptional function of p53 was inhibited, and we observed a down-regulation of p21(waf1/cip1), a p53-responsive gene. The increase in levels of the p53 protein was mediated by enhanced translation of the p53 protein. Additionally, triptolide induced accumulation of cells in S phase and blocked doxorubicin-mediated accumulation of cells in G(2)/M and doxorubicin-mediated induction of p21. Our data suggest that triptolide, by blocking p21-mediated growth arrest, enhances apoptosis in tumor cells.
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PMID:Triptolide and chemotherapy cooperate in tumor cell apoptosis. A role for the p53 pathway. 1105 49


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