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)

Cells respond to DNA damage in a complex way and the fate of damaged cells depends on the balance between pro- and antiapoptotic signals. This is of crucial importance in cancer as genotoxic stress is implied both in oncogenesis and in classical tumor therapies. p53-induced protein with a death domain (PIDD), initially described as a p53-inducible gene, is one of the molecular switches able to activate a survival or apoptotic program. Two isoforms of PIDD, PIDD (isoform 1) and LRDD (isoform 2), have already been reported and we describe here a third isoform. These three isoforms are differentially expressed in tissues and cell lines. Genotoxic stress only affects PIDD isoform 3 mRNA levels, whereas isoforms 1 and 2 mRNA levels remain unchanged. All isoforms are capable of activating nuclear factor-kappaB in response to genotoxic stress, but only isoform 1 interacts with RIP-associated ICH-1/CED-3 homologous protein with a death domain and activates caspase-2. Isoform 2 counteracts the pro-apoptotic function of isoform 1, whereas isoform 3 enhances it. Thus, the differential splicing of PIDD mRNA leads to the formation of at least three proteins with antagonizing/agonizing functions, thereby regulating cell fate in response to DNA damage.
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PMID:p53-induced protein with a death domain (PIDD) isoforms differentially activate nuclear factor-kappaB and caspase-2 in response to genotoxic stress. 1763 55

When treated with some DNA-damaging agents, human tumor-derived H1299 cells expressing inducible versions of wild-type or mutant p53 with inactive transactivation domain I (p53(Q22/S23)) undergo apoptosis as evidenced by cytochrome c release, nuclear fragmentation, and sub-G1 DNA content. Apoptosis induced by p53(Q22/S23) is relatively slow, however, and key downstream effector caspases are not activated. Nevertheless, with either version of p53, caspase 2 activation is required for release of cytochrome c and cell death. Remarkably, although p53(Q22/S23) is known to be defective in transcriptional activation of numerous p53 target genes, it can induce expression of proapoptotic targets including PIDD and AIP1 at least to the same extent as wild-type p53. Furthermore, RNAi silencing of PIDD, previously shown to be required for caspase 2 activation, suppresses apoptosis by both wild-type p53 and p53(Q22/S23). Thus, the initial stage of DNA damage-facilitated, p53-mediated apoptosis occurs by a PIDD- and caspase 2-dependent mechanism, and p53's full transcriptional regulatory functions may be required only for events that are downstream of cytochrome c release.
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PMID:A role for caspase 2 and PIDD in the process of p53-mediated apoptosis. 1823 95

Upon treatment with some DNA damaging agents, human H1299 tumor-derived cells expressing inducible versions of wild-type or mutant p53 with inactive transactivation domain I (p53(Q22/S23)) undergo apoptosis. In cells expressing either version of p53, caspase 2 activation is required for release of cytochrome c and cell death. Furthermore, silencing of PIDD (a factor previously shown to be required for caspase 2 activation) by siRNA suppresses apoptosis by both wild-type p53 and p53(Q22/S23). Despite the finding that caspase 2 is essential for DNA damage-facilitated, p53-mediated apoptosis, induction of wild-type p53 (with or without DNA damage) resulted in a reduction of caspase 2 mRNA and protein levels. In this study we sought to provide a mechanism for the negative regulation of caspase 2 by p53 as well as provide insight as to why p53 may repress a key mediator of p53-dependent apoptosis. Mechanistically, we show that DNA binding and/or transactivation domains of p53 are crucial for mediating transrepression. Further, expression of p21 (in p53-null cells inducibly expressing p21) is sufficient to mediate repression of caspase 2. Deletion of p21 or E2F-1 not only abrogated repression of caspase 2, but also stimulated the expression of caspase 2 above basal levels, implicating the requirement for an intact p21/Rb/E2F pathway in the downregulation of caspase 2. As this p53/p21-dependent repression of caspase 2 can occur in the absence of DNA damage, caspase 2 repression does not simply seem to be a consequence of the apoptotic process. Downregulation of caspase 2 levels by p53 may help to determine cell fate by preventing cell death when unnecessary.
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PMID:Caspase 2 is both required for p53-mediated apoptosis and downregulated by p53 in a p21-dependent manner. 1841 48

p73, the p53 homologue, exists as a transactivation-domain-proficient TAp73 or deficient deltaN(DN)p73 form. Expectedly, the oncogenic DNp73 that is capable of inactivating both TAp73 and p53 function, is over-expressed in cancers. However, the role of TAp73, which exhibits tumour-suppressive properties in gain or loss of function models, in human cancers where it is hyper-expressed is unclear. We demonstrate here that both TAp73 and DNp73 are able to specifically transactivate the expression of the anti-apoptotic member of the caspase family, caspase-2(S). Neither p53 nor TAp63 has this property, and only the p73beta form, but not the p73alpha form, has this competency. Caspase-2 promoter analysis revealed that a non-canonical, 18 bp GC-rich Sp-1-binding site-containing region is essential for p73beta-mediated activation. However, mutating the Sp-1-binding site or silencing Sp-1 expression did not affect p73beta's transactivation ability. In vitro DNA binding and in vivo chromatin immunoprecipitation assays indicated that p73beta is capable of directly binding to this region, and consistently, DNA binding p73 mutant was unable to transactivate caspase-2(S). Finally, DNp73beta over-expression in neuroblastoma cells led to resistance to cell death, and concomitantly to elevated levels of caspase-2(S.) Silencing p73 expression in these cells led to reduction of caspase-2(S) expression and increased cell death. Together, the data identifies caspase-2(S) as a novel transcriptional target common to both TAp73 and DNp73, and raises the possibility that TAp73 may be over-expressed in cancers to promote survival.
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PMID:TAp73beta and DNp73beta activate the expression of the pro-survival caspase-2S. 1861 50

Caspase-2 is unique among all the mammalian caspases in that it is the only caspase that is present constitutively in the cell nucleus, in addition to other cellular compartments. However, the functional significance of this nuclear localization is unknown. Here we show that DNA damage induced by gamma-radiation triggers the phosphorylation of nuclear caspase-2 at the S122 site within its prodomain, leading to its cleavage and activation. This phosphorylation is carried out by the nuclear serine/threonine protein kinase DNA-PKcs and promoted by the p53-inducible death-domain-containing protein PIDD within a large nuclear protein complex consisting of DNA-PKcs, PIDD, and caspase-2, which we have named the DNA-PKcs-PIDDosome. This phosphorylation and the catalytic activity of caspase-2 are involved in the maintenance of a G2/M DNA damage checkpoint and DNA repair mediated by the nonhomologous end-joining (NHEJ) pathway. The DNA-PKcs-PIDDosome thus represents a protein complex that impacts mammalian G2/M DNA damage checkpoint and NHEJ.
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PMID:DNA-PKcs-PIDDosome: a nuclear caspase-2-activating complex with role in G2/M checkpoint maintenance. 2145 74

MCP-1 (monocyte chemotactic protein-1) plays a critical role in the development of heart failure that is known to involve apoptosis. How MCP-1 contributes to cell death involved in the development of heart disease is not understood. In the present study we show that MCP-1 causes death in cardiac myoblasts, H9c2 cells, by inducing oxidative stress which causes ER stress leading to autophagy via a novel zinc-finger protein, MCPIP (MCP-1-induced protein). MCPIP expression caused cell death, and knockdown of MCPIP attenuated MCP-1-induced cell death. It caused induction of iNOS (inducible NO synthase), translocation of the NADPH oxidase subunit phox47 from the cytoplasm to the membrane, production of ROS (reactive oxygen species), and induction of ER (endoplasmic reticulum) stress markers HSP40 (heat-shock protein 40), PDI (protein disulfide-isomerase), GRP78 (guanine-nucleotide-releasing protein 78) and IRE1alpha (inositol-requiring enzyme 1alpha). It also caused autophagy, as indicated by beclin-1 induction, cleavage of LC3 (microtubule-associated protein 1 light chain 3) and autophagolysosome formation, and apoptosis, as indicated by caspase 3 activation and TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling) assay. Inhibitors of oxidative stress, including CeO2 nanoparticles, inhibited ROS formation, ER stress, autophagy and cell death. Specific inhibitors of ER stress inhibited autophagy and cell death as did knockdown of the ER stress signalling protein IRE1. Knockdown of beclin-1 and autophagy inhibitors prevented cell death. This cell death involved caspase 2 and caspase 12, as specific inhibitors of these caspases prevented MCPIP-induced cell death. Microarray analysis showed that MCPIP expression caused induction of a variety of genes known to be involved in cell death. MCPIP caused activation of JNK (c-Jun N-terminal kinase) and p38 and induction of p53 and PUMA (p53 up-regulated modulator of apoptosis). Taken together, these results suggest that MCPIP induces ROS/RNS (reactive nitrogen species) production that causes ER stress which leads to autophagy and apoptosis through caspase 2/12 and IRE1alpha-JNK/p38-p53-PUMA pathway. These results provide the first molecular insights into the mechanism by which elevated MCP-1 levels associated with chronic inflammation may contribute to the development of heart failure.
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PMID:MCP-1 causes cardiomyoblast death via autophagy resulting from ER stress caused by oxidative stress generated by inducing a novel zinc-finger protein, MCPIP. 1992 54

HCT116 (p21(-/-)) human colon carcinoma cells treated with mithramycin SK (MSK), a novel analog of the antitumor antibiotic mithramycin A (MTA), were transiently arrested in G2/M, with some cells entering a faulty mitotic cycle without cytokinesis that resulted in G1-like cell arrest, which consisted of post-mitotic aneuploid G1 cells. Some of these cells synthesized DNA and elicited an apoptotic response. The absence of p21(WAF1) made HCT116 cells more sensitive to MSK than to the related MTA. MSK also showed higher antiproliferative activity than MTA on HCT116 cells with different genetic backgrounds, including those lacking the p53 gene. Apoptosis in MSK-treated p21(-/-) cells involved caspase 2 rather than caspase 3. Untreated HCT116 (p21(-/-)) cells presented a little caspase 3 activity, which increased slightly after treatment with MSK. The apoptotic response in p21(-/-) cells comprised caspase 2 acting as an executor caspase together with a loss of mitochondrial membrane potential that may be initiated by caspase 2. In contrast, caspase 3 was activated in wild-type HCT116 after treatment with MSK.
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PMID:Cellular response and activation of apoptosis by mithramycin SK in p21(WAF1)-deficient HCT116 human colon carcinoma cells. 1996 19

Many studies have shown that DNA mismatch repair (MMR) has a role beyond that of repair in response to several types of DNA damage, including ultraviolet radiation (UV). We have demonstrated previously that the MMR-dependent component of UVB-induced apoptosis is integral to the suppression of UVB-induced tumorigenesis. Here we demonstrate that Msh6-dependent UVB-induced apoptotic pathway is both activated via the mitochondria and p53-independent. In addition, we have shown for the first time that caspase 2, an initiator caspase, localizes to the centrosomes in mitotic primary mouse embryonic fibroblasts, irrespective of MMR status and UVB treatment.
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PMID:Defining the DNA mismatch repair-dependent apoptotic pathway in primary cells: evidence for p53-independence and involvement of centrosomal caspase 2. 2002 6

Caspase-2, the most conserved member of the caspase family, has long been recognized as an important protein in the regulation of apoptosis. However, due to a lack of phenotype in caspase-2 knock-out mice, its precise role has been questioned. Recently, several publications have described new mechanisms regulating caspase-2 activation, including its role within an activating complex named the PIDDosome, linking caspase-2 function to p53. Consistent with this, evidence is accumulating for potential roles of caspase-2 in non-apoptotic processes, including cell cycle regulation and DNA repair. In addition, a tumor-suppressor function has been suggested for caspase-2. Here we discuss how different PIDDosome complexes could be involved in mechanisms regulating the switch between the various functions of caspase-2.
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PMID:The unpredictable caspase-2: what can it do? 2006 Nov 49

The oligonucleotide Dz13 is a DNA enzyme (deoxyribozyme) that cleaves c-Jun mRNA. It has efficacious effects against tumors directly, is active against tumor-induced angiogenesis, inhibits neointima formation after arterial injury, and controls inflammatory responses. The off-target effects of Dz13 may in fact be driving some of these potentially therapeutic effects, though no mechanisms have been clearly defined in target cells. To this end, we here show that when a panel of human tumor cells that naturally propagate in bone are challenged with Dz13, the tumor suppressor E2F1 is upregulated regardless of cellular p53 status. The piddosomal components, p53-induced protein with a death domain and caspase-2, were translocated to the nucleus when deoxyribozymes were incubated with cells, but RIP associated Ich-1/CED homologous protein with death domain levels increased throughout the cell with either Dz13 or its scrambled control oligonucleotide. In response to Dz13-mediated cytotoxicity, cells upregulated levels of ERK, Akt, and p38. Summarily, these results suggest a cytotoxic stress (resembling DNA damage) response of tumor cells to Dz13, which induces apoptosis via the activation of inhibitor of caspase-activated deoxyribonuclease and protein kinase C delta. In vivo, in tumor-in-bone orthotopic and clinically relevant models for prostate and breast cancer metastasis, and a novel spontaneously metastasizing model for osteosarcoma (OS), Dz13 decreased growth in bone, and also metastasis for OS. This new model for OS was assessed to be clinically relevant in its expression of typical bone markers, osteopontin and osteocalcin. These results provide an off-target mechanism for Dz13 function, but this may be useful therapeutically against tumors.
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PMID:Dz13 induces a cytotoxic stress response with upregulation of E2F1 in tumor cells metastasizing to or from bone. 2040 96


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