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)

DNA-PK (DNA-dependent protein kinase) is a double-strand break sensor involved in DNA repair and signal transduction. In the present study, we constructed site-directed cross-linking probes to explore the range of DNA discontinuities that are recognized by DNA-PK(CS) (DNA-PK catalytic subunit). A comparison between different substrate architectures showed that DNA-PK(CS) associates preferentially with the crossover region of synthetic Holliday junctions. This interaction with four-way junctions was preserved when biotin-streptavidin complexes were assembled at the termini to exclude the binding of Ku proteins. The association of DNA-PK(CS) with Holliday junctions was salt-labile even in the presence of Ku proteins, but this interaction could be stabilized when the DNA probes were incubated with the endogenous enzyme in nuclear extracts of human cells. Cross-linking of the endogenous enzyme in cellular extracts also demonstrated that DNA-PK(CS) binds to DNA ends and four-way junctions with similar affinities in the context of a nuclear protein environment. Kinase assays using p53 proteins as a substrate showed that, in association with four-way structures, DNA-PK(CS) adopts an active conformation different from that in the complex with linear DNA. Our results are consistent with a structure-specific, but Ku- and DNA end-independent, recruitment of DNA-PK(CS) to Holliday junction intermediates. This observation suggests an unexpected functional link between the two main pathways that are responsible for the repair of DNA double-strand breaks in mammalian cells.
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PMID:Binding of the DNA-dependent protein kinase catalytic subunit to Holliday junctions. 1503 58

Gene-environment interactions are implicated in congenital human disorders. Accordingly, there is a pressing need to develop animal models of human disease, which are the product of defined gene-environment interactions. Previously, our laboratory demonstrated that gestational salt stress of bradykinin B(2) receptor (B(2)R)-null mice induces renal dysgenesis and early death of the offspring. In contrast, salt-stressed B(2)R +/+ or +/- littermates have normal development. The present study investigates the mechanisms underlying the susceptibility of B(2)R-null mice to renal dysgenesis. Proteomic and conventional Western blot screens identified E-cadherin among the differentially repressed proteins in B(2)R-/- kidneys, whereas the checkpoint kinase Chk1 and its substrate P-Ser(20) p53 were induced. We tested the hypothesis that p53 mediates repression of E-cadherin gene expression and is causally linked to the renal dysgenesis. Genetic crosses between B(2)R -/- and p53+/- mice revealed that germline reduction of p53 gene dosage rescues B(2)R-/- mice from renal dysgenesis and restores kidney E-cadherin gene expression. Furthermore, gamma-irradiation induces repression of E-cadherin gene expression in p53+/+ but not -/- cells. In transient transfection assays, p53 repressed human E-cadherin promoter-driven reporter activity, whereas a mutant p53, which cannot bind DNA, did not. Functional promoter analysis indicated the presence of a p53-responsive element in exon 1, which partially mediates p53-induced repression. Chromatin immunoprecipitation assays revealed that p53 inhibits histone acetylation of the E-cadherin promoter. Treatment with a histone deacetylase inhibitor reversed both p53-mediated promoter repression and deacetylation. In conclusion, this study demonstrates that gene-environment interactions cooperate to induce congenital defects through p53 activation.
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PMID:A novel pathological role of p53 in kidney development revealed by gene-environment interactions. 1538 1

Protein B23/nucleophosmin is a multifunctional protein that plays roles in ribosome biogenesis, control of centrosome duplication, and regulation of p53 expression. A yeast two-hybrid screen was performed in a search for interaction partners of B23. The complementary DNA for a highly acidic protein, nucleoplasmin 3 (NPM3), was found in multiple positive clones. Protein NPM3 and its interaction with B23 were further characterized. Endogenous B23 was able to be co-immunoprecipitated with NPM3, and this complex was resistant to ribonuclease treatment and high concentrations of salt. The N-terminal 35-90 amino acids of B23 were found to be required for their interaction. Separate co-immunoprecipitation studies of B23 and NPM3 suggested the existence of two different complexes, one containing B23 and 28 S ribosomal RNA (rRNA) and another composed of B23, NPM3, and other proteins, but no RNA. NPM3 was localized in the nucleolus, and its nucleolar localization depended on active rRNA transcription. In the cells overexpressing NPM3, there were decreased rates of pre-rRNA synthesis and processing. Overexpression of a mutant of NPM3 that did not interact with B23 did not alter pre-rRNA synthesis and processing, suggesting that the interaction of NPM3 with B23 plays a role in the ribosome biogenesis.
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PMID:Protein NPM3 interacts with the multifunctional nucleolar protein B23/nucleophosmin and inhibits ribosome biogenesis. 1559 47

We recently reported a beta-peptide foldamer, beta53-1, that folds into a 14-helix in aqueous solution, binds the oncoprotein hDM2 with submicromolar affinity, and potently inhibits the interaction of hDM2 with a peptide derived from the activation domain of p53 (p53AD). Here, we present the solution structure of beta53-1 in methanol. Details of the structure illustrate fundamental and novel elements of beta-peptide folding and recognition. These elements include the detailed arrangement of a complex, 14-helix-stabilizing salt bridge on one helical face, and a unique "wedge into cleft" packing interaction along a second. The structure also reveals how a subtle distortion in the beta53-1 14-helix geometry alters the presentation of its recognition epitope, rendering it particularly well suited for alpha-helix mimicry. The solution structure of beta53-1 demonstrates that well folded beta-peptide oligomers can effectively present an extended, highly variable surface that could be used as a general platform for targeting critical protein-protein interfaces.
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PMID:Solution structure of a beta-peptide ligand for hDM2. 1578 63

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 3-AP, 667-coumate, 9-aminocamptothecin; Ad5CMV-p53, AES-14, alefacept, anecortave acetate, APC-8024, APD-356, asoprisnil; Bevacizumab, bimakalim, bimatoprost, BLP-25, BR-1; Caspofungin acetate, cetuximab, cypher; Darbepoetin alfa, dexanabinol, dextromethorphan/quinidine sulfate, DNA.HIVA; Efaproxiral sodium, ertapenem sodium; Frovatriptan; HuMax-EGFr, HYB-2055, gamma-hydroxybutyrate sodium, Id-KLH vaccine, imatinib mesylate; Lapatinib, lonafarnib, Motexafin lutetium, MVA.HIVA, mycophenolic acid sodium salt; Nesiritide, NS-2330; Olmesartan medoxomil; Peginterferon alfa-2a, peginterferon alfa-2b, peginterferon alfa-2b/ribavirin, pemetrexed disodium, perifosine, pimecrolimus, pregabalin; QbG-10; Ralfinamide, rasburicase, rFGF-2, Ro-31-7453; Sitaxsentan sodium, sorafenib; Tadalafil, TC-1734, telmisartan/hydrochlorothiazide, tenofovir disoproxil fumarate, thymus nuclear protein, tipifarnib; Vandetanib, vibriolysin, vildagliptin, voriconazole.
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PMID:Gateways to clinical trials. 1583 66

Methylselenol has been implicated as an active metabolite for the anticancer effect of selenium in part through the induction of cancer cell apoptosis. Since inactivation of the AKT/protein kinase B negative regulator gene PTEN (phosphatase and tensin homologue deleted on chromosome 10) is common in prostate cancer (PCa), we compared PTEN wild-type DU145 PCa cells (low basal AKT activity) with PTEN-mutant LNCaP PCa cells (high basal AKT activity) for their apoptosis responses to the methylselenol precursor methylseleninic acid (MSeA) and sodium selenite, an inorganic salt. Our results show that LNCaP cells withstood approximately 4 times higher doses of MSeA than DU145 cells, although they were slightly more sensitive than the latter to selenite-induced apoptosis. Treatment by MSeA modestly attenuated AKT phosphorylation and increased phospho-ERK1/2 in LNCaP cells. Selenite treatment increased the phosphorylation of p53 Ser15 and both kinases, but the selenite-induced apoptosis was not influenced by chemical inhibitors of either kinase. In contrast, PI3K/AKT inhibitors greatly sensitized LNCaP cells to apoptosis induced by MSeA, accompanied by increased mitochondrial release of cytochrome c and multiple caspase activation without changing p53 Ser15 phosphorylation. The apoptosis was further accentuated by extracellular signal regulated kinases 1 and 2 (ERK1/2) inhibition without further increase in cytochrome c release. The general caspase inhibitor z-VAD-fmk completely blocked MSeA-induced apoptosis when both kinases were inhibited, whereas a caspase-8 inhibitor exerted a greater protection than did a caspase-9 inhibitor. Transfection of DU145 cells with a constitutively active AKT increased their resistance to MSeA-induced apoptosis. In summary, AKT played an important role in regulating apoptosis sensitivity of LNCaP and DU145 cells to MSeA. An MSeA-induced activation of ERK1/2 in LNCaP cells also contributed to resistance to apoptosis. However, these kinases did not significantly regulate caspase-mediated apoptosis induced by selenite in LNCaP cells. These findings support the differential involvement of these protein kinase pathways in regulating apoptosis induction by different forms of selenium.
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PMID:PKB/AKT and ERK regulation of caspase-mediated apoptosis by methylseleninic acid in LNCaP prostate cancer cells. 1584 51

We describe in molecular detail how disruption of an intermonomer salt bridge (Arg337-Asp352) leads to partial destabilization of the p53 tetramerization domain and a dramatically increased propensity to form amyloid fibrils. At pH 4.0 and 37 degrees C, a p53 tetramerization domain mutant (p53tet-R337H), associated with adrenocortical carcinoma in children, readily formed amyloid fibrils, while the wild-type (p53tet-wt) did not. We characterized these proteins by equilibrium denaturation, 13C(alpha) secondary chemical shifts, (1H)-15N heteronuclear NOEs, and H/D exchange. Although p53tet-R337H was thermodynamically less stable, NMR data indicated that the two proteins had similar secondary structure and molecular dynamics. NMR derived pK(a) values indicated that at low pH the R337H mutation partially disrupted an intermonomer salt bridge. Backbone H/D exchange results showed that for at least a small population of p53tet-R337H molecules disruption of this salt bridge resulted in partial destabilization of the protein. It is proposed that this decrease in p53tet-R337H stability resulted in an increased propensity to form amyloid fibrils.
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PMID:Disruption of an intermonomer salt bridge in the p53 tetramerization domain results in an increased propensity to form amyloid fibrils. 1626 Jul 57

Nearly all cervical cancers are associated with the high-risk subtypes of human papillomavirus (HPV) expressing the E6 and E7 oncoproteins. The E6 and E7 oncoproteins reduce cellular levels of the p53 and the retinoblastoma (pRb) tumor suppressors, respectively, and represent an important component of the malignant phenotype. Several groups have shown that treatment with cidofovir suppresses levels of E6 and E7, restoring cellular p53 and pRb levels, in turn slowing cell replication and increasing the susceptibility of the cancer cells to radiation and apoptosis. Recently, our group synthesized alkoxyalkyl esters of cidofovir, which were found to be >100 times more active than unmodified cidofovir in vitro against various double-stranded DNA viruses, including cytomegalovirus, herpes simplex virus, adenoviruses, cowpox, vaccinia, and variola viruses. We compared the activity of octadecyloxyethyl-cidofovir (ODE-CDV) and oleyloxyethyl-cidofovir (OLE-CDV) with that of unmodified cidofovir against both HPV-negative and HPV-positive cervical cancer cells. We compared the antiproliferation activity in CaSki, HeLa, and Me-180 cells, prototypical HPV-positive cell lines bearing the HPV-16, HPV-18, and HPV-68 high-risk subtypes, with the activity in C33A cells, a cervical cancer cell line lacking HPV, and in nonmalignant primary human foreskin fibroblast cells. OLE-CDV and ODE-CDV were several logs more potent than cidofovir in CaSki, Me-180, HeLa, and C33A cervical cancer cells as determined by 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt proliferation assay. Cell cycle analysis indicates that the cidofovir analogues interfere with passage of dividing cells through the S phase. ODE-CDV and OLE-CDV were 500 to 17,000 times more active than cidofovir in inhibiting the growth of cervical cancer cells. ODE-CDV and OLE-CDV showed selectivity for cervical cancer cells versus nonmalignant human foreskin fibroblast cells and warrant further investigation as potential therapies for cervical cancer.
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PMID:Enhanced antiproliferative effects of alkoxyalkyl esters of cidofovir in human cervical cancer cells in vitro. 1643 74

In response to gestational high salt intake, BdkrB2-/- embryos acquire an aberrant renal phenotype mimicking renal dysplasia in humans. Genetic analysis identified p53 as a mediator of the renal dysplasia in salt-stressed BdkrB2-/- mice, acting partly via repression of terminal epithelial differentiation genes. The present study tested the hypothesis that inactivation of BdkrB2 predisposes the salt-stressed embryo to p53-mediated metanephric apoptosis. Newborn BdkrB2-/- pups exhibited hyperphosphorylation of metanephric p53 on serine 20 (mouse serine 23), a modification known to increase p53 stability and apoptotic activity. As a result, there was widespread, ectopic expression of p53 in the BdkrB2-/- kidney. However, no differences were found in the apoptosis index or gene expression in BdkrB2-/- and +/+ kidneys, indicating that p53 stabilization as a result of BdkrB2 inactivation is not sufficient to induce metanephric apoptosis. On gestational salt stress, fulminant metanephric apoptosis and enhanced Bax gene expression occurred in BdkrB2-/- but not their +/- or +/+ littermates. Germline deletion of p53 from BdkrB2-/- mice prevented Bax activation and normalized the apoptosis index. Rescue of metanephric apoptosis in BdkrB2-/- mice was similarly achieved by Bax gene deletion. Aberrant apoptosis in salt-stressed BdkrB2-/- mice was triggered on embryonic day E15.5 and involved both ureteric bud (UB) and metanephric mesenchyme-derived nephron elements. Cultured E12.5 salt-stressed BdkrB2-/- metanephroi manifested stunted UB branching compared with +/- and +/+ littermates; the abnormal UB branching was corrected by p53 deletion. Our results suggest a model whereby a seemingly silent genetic mutation of BdkrB2 predisposes mice to renal dysplasia by creating a "preapoptotic" state through p53 activation.
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PMID:Susceptibility to metanephric apoptosis in bradykinin B2 receptor null mice via the p53-Bax pathway. 1657 98

Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 131-I-chlorotoxin; Ad5CMV-p53, adalimumab, albumin interferon alfa, alemtuzumab, aliskiren fumarate, aminolevulinic acid methyl ester, anakinra, AR-C126532, atomoxetine hydrochloride; Bevacizumab, bosentan, botulinum toxin type B, brimonidine tartrate/timolol maleate; Calcipotriol/betamethasone dipropionate, cangrelor tetrasodium, cetuximab, ciclesonide, cinacalcet hydrochloride, collagen-PVP, Cypher; Darbepoetin alfa, darusentan, dasatinib, denosumab, desloratadine, dexosome vaccine (lung cancer), dexrazoxane, dextromethorphan/quinidine sulfate, duloxetine hydrochloride; ED-71, eel calcitonin, efalizumab, entecavir, etoricoxib; Falciparum merozoite protein-1/AS02A, fenretinide, fondaparinux sodium; gamma-Hydroxybutyrate sodium, gefitinib, ghrelin (human); hLM609; Icatibant acetate, imatinib mesylate, ipsapirone, irofulven; LBH-589, LE-AON, levocetirizine, LY-450139; Malaria vaccine, mapatumumab, motexafin gadolinium, muraglitazar, mycophenolic acid sodium salt; nab-paclitaxel, nelarabine; O6-Benzylguanine, olmesartan medoxomil, orbofiban acetate; Panitumumab, peginterferon alfa-2a, peginterferon alfa-2b, pemetrexed disodium, peptide YY3-36, pleconaril, prasterone, pregabalin; Ranolazine, rebimastat, recombinant malaria vaccine, rosuvastatin calcium; SQN-400; Taxus, tegaserod maleate, tenofovir disoproxil fumarate, teriparatide, troxacitabine; Valganciclovir hydrochloride, Val-Tyr sardine peptidase, VNP-40101M, vorinostat.
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PMID:Gateways to clinical trials. 1684 50


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