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)

Size separation after UV-endonuclease digestion of DNA from UV-irradiated human cells using denaturing conditions fractionates the genome based on cyclobutane pyrimidine dimer content. We have examined the largest molecules available (50-80 kb; about 5% of the DNA) after fractionation and those of average size (5-15 kb) for content of some specific genes. We find that the largest molecules are not a representative sampling of the genome. Three contiguous genes located in a G+C-rich isochore (tyrosine hydroxylase, insulin, insulin-like growth factor II) have concentrations two to three times greater in the largest molecules. This shows that this genomic region has fewer pyrimidine dimers than most other genomic regions. In contrast, the beta-actin genomic region, which has a similar G+C content, has an equal concentration in both fractions as do the p53 and beta-globin genomic regions, which are A+T-rich. These data show that DNA damage in the form of cyclobutane pyrimidine dimers occurs with different probabilities in specific isochores. Part of the reason may be the relative G+C content, but other factors must play a significant role. We also report that the transcriptionally inactive insulin region is repaired at the genome-overall rate in normal cells and is not repaired in xeroderma pigmentosum complementation group C cells.
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PMID:Identification of a large genomic region in UV-irradiated human cells which has fewer cyclobutane pyrimidine dimers than most genomic regions. 748 Jan 36

We have examined MPTP toxicity to dopamine neurons of mice homozygous for a transgenic knockout of the p53 growth control gene (p53-/-). MPTP at a total dose of 96 mg/kg administered in four doses over two days produced a non-homogeneous loss of striatal dopamine transport sites and quantitatively reduced 3H-mazindol binding to similar degrees in p53-/- and wild type controls 2 and 3 weeks after starting MPTP. Nigral DA neurons stained immunohistochemically for tyrosine hydroxylase were counted using both manual and automated methods and found to be reduced 29-34% in wild type controls but were not reduced in p53-/-. Mean DA neuronal surface areas were reduced 63-68% by MPTP in controls and 35-50% in p53-/-. We conclude that p53 protein appears necessary for complete expression of MPTP neurotoxicity to dopamine neurons. Our findings suggest that the p53 gene and other growth control genes may regulate dopamine neuronal death in PD.
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PMID:Dopamine neurons from transgenic mice with a knockout of the p53 gene resist MPTP neurotoxicity. 891 Sep 1

Although there is no definitive evidence of the association of human cytomegalovirus (HCMV) infection with human cancers, the oncogenic potential of HCMV has been well established by in vitro studies demonstrating the ability of UV-irradiated or infectious virus to transform a variety of cells. After prolonged passaging the transformed cell type was maintained while HCMV DNA sequences were no more detectable. Three morphological transforming regions (mtr) of HCMV have been identified. The effects of HCMV on cellular functions which may be associated with the malignant phenotype include the expression of oncogenes and transcriptional activation of growth factors and interleukin synthesis. In infected cells, HCMV induces cytoskeletal alterations and changes in expression of cell surface receptors for extracellular matrix proteins which could result in increased motility and dissemination of cancer cells. Several human neuroblastoma cell lines undergo maturation in different neural crest derived cell types upon treatment with oncogenic potential agents, i.e. retinoic acid. The persistent HCMV infection of neuroblastoma cells (> 1 year) is accompanied by the increased expression of oncoproteins (i.e. N-myc) and decreased expression of tyrosine hydroxylase and dopamine-beta-hydroxylase. The activation of the cellular metabolism is due to HCMV binding to cellular receptors (prior to virus gene expression) and to the activity of HCMV immediate early (IE) gene products. IE proteins act directly as transcriptional activators or their activity is mediated by a variety of cellular transcription factors. HCMV infection may result in activation of promoters of cellular genes coding for cytokines, replication enzymes, proto-oncogenes and viral promoters. Recently it has been demonstrated that HCMV IE proteins block apoptosis probably by suppressing the ability of the antioncogene p53 to activate a reporter gene. The interactions of HCMV with tumor suppressor proteins such as p53 or retinoblastoma (pRb) susceptibility protein are reminiscent of those mediated by the oncoproteins of DNA tumor viruses. The acquisition of a fully malignant phenotype by normal cells is thought to require several mutations in a number of cellular genes. In this connection, HCMV may play the role of a nonobligate either direct or indirect cofactor for tumor genesis, e.g. by blocking apoptosis, which may be an essential requirement for tumor progression. Due to the stimulation of growth factors and/or inhibition of antioncogenes by its gene products, HCMV may modulate the malignant potential for tumor cells.
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PMID:Modulatory effects of human cytomegalovirus infection on malignant properties of cancer cells. 907 67

p53-knockout mice provide a useful model to test the role of p53 in the neurotoxic effects of drugs in vivo. To test the involvement of p53 in methamphetamine (METH)-induced toxicity, wild-type mice, as well as heterozygous and homozygous p53-knockout male mice, were administered four injections of three different doses (2.5, 5.0, and 10.0 mg/kg) of the drug given at 2-h intervals within the space of 1 day. METH caused a marked dose-dependent loss of dopamine transporters in both the striatum and the nucleus accumbens of wild-type mice killed 2 weeks after drug administration. However, this METH-induced decrease in dopamine transporters was attenuated in both homozygous and heterozygous p53-knockout mice, with homozygous animals showing significantly greater protection. The possibility for p53 involvement in METH-induced toxicity was also supported by the observation that METH caused marked increases in p53-like immunoreactivity in the striata of wild-type mice and very little change in heterozygous p53-knockout mice, whereas no p53-like immunostaining was detected in the homozygous p53-knockout mice. Further support for p53 involvement was provided by the fact that METH treatment caused significant decreases in dopamine transporter mRNA and the number of tyrosine hydroxylase-positive cells in the substantia nigra pars compacta and the ventral tegmental area of wild-type but not homozygous p53-knockout mice killed 2 weeks after cessation of METH administration. These results provide concordant evidence for a role of the tumor suppressor, p53, in the long-term deleterious effects of a drug acting on brain dopamine systems.
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PMID:p53-knockout mice are protected against the long-term effects of methamphetamine on dopaminergic terminals and cell bodies. 923 39

Oncocytic neoplasms of the adrenal gland are rare. We describe the clinicopathologic and immunohistochemical findings of seven oncocytic adrenocortical neoplasms, five oncocytomas, and two oncocytic neoplasms of uncertain malignant potential. Three tumors were studied using electron microscopy. These neoplasms occurred in five women and two men (median age, 55 years) with no clinical evidence that the neoplasms were functional. The size of the neoplasms varied from 5.0 cm to 13.5 cm. Histologically, each neoplasm was composed exclusively of oncocytes. The oncocytomas had very low or absent mitotic activity and no evidence of necrosis. The two oncocytic neoplasms of uncertain malignant potential had increased mitotic activity and necrosis but no evidence of invasion or metastases. Nuclear atypia, either focal or generalized, was found in all neoplasms. Immunohistochemical studies performed using fixed, paraffin-embedded sections showed strong reactivity with the mitochondrial antibody mES-13 in all neoplasms. Four of five oncocytomas and one oncocytic neoplasm of uncertain malignant potential expressed keratin, predominantly keratin 18, as shown using the CAM 5.2 and AE3 antibodies. Two neuroendocrine-associated markers, neuron specific enolase and synaptophysin, were positive in seven and five neoplasms, respectively. However, all neoplasms were negative for the other neuroendocrine markers tested, including chromogranin A, tyrosine hydroxylase, and dopamine beta-hydroxylase, as well as for epithelial membrane antigen, S100, and p53. Using the MIB-1 (Ki-67) antibody, proliferative activity was increased in both oncocytic neoplasms of uncertain malignant potential. All six patients with available clinical follow-up data are alive without evidence disease, although the follow-up interval is relatively short (< 2 years) for the two patients with oncocytic neoplasms of uncertain malignant potential. We conclude that oncocytic adrenocortical neoplasms are nonfunctional tumors that can become large before they are detected by radiologic studies. The majority of neoplasms are benign and should not be misdiagnosed as carcinoma.
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PMID:Oncocytic adrenocortical neoplasms: a report of seven cases and review of the literature. 959 31

The clinicopathological features of 56 patients with mucinous cystic tumors (MCTs) of the pancreas were studied. Particular attention was paid to the prognosis of MCTs and the relationship to their ovarian, hepatic, and retroperitoneal counterparts. To distinguish MCTs from pancreatic intraductal papillary-mucinous tumors, MCTs were defined as tumors lacking communication with the duct system and containing mucin-producing epithelium, usually supported by ovarian-like stroma. All 56 tumors occurred in women (mean age 48.2 years) and were preferentially (93%) located in the body and tail of the pancreas. In accordance with the WHO classification, MCTs were divided into adenomas (n = 22), borderline tumors (n= 12), and noninvasive and invasive carcinomas (n = 22). Survival analysis revealed the extent of invasion to be the most significant prognostic factor (p<0.0001). Malignancy correlated with multilocularity and presence of papillary projections or mural nodules, loss of ovarian-like stroma, and p53 immunoreactivity. Stromal luteinization with expression of tyrosine hydroxylase, calretinin, or alpha inhibin was found in 66% of the cases. We conclude that the biologic behavior of MCTs is predictable on the basis of the extent of invasion. The similarities (i.e. gender, morphology, stromal luteinization) between pancreatic MCT and its ovarian, hepatobiliary, and retroperitoneal counterparts suggest a common pathway for their development.
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PMID:Mucinous cystic tumors of the pancreas: clinicopathological features, prognosis, and relationship to other mucinous cystic tumors. 1019 70

Apoptosis is a prerequisite to model the developing nervous system. However, an increased rate of cell death in the adult nervous system underlies neurodegenerative disease and is a hallmark of multiple sclerosis (MS) Alzheimer's- (AD), Parkinson- (PD), or Huntington's disease (HD). Cell surface receptors (e.g., CD95/APO-1/Fas; TNF receptor) and their ligands (CD95-L; TNF) as well as evolutionarily conserved mechanisms involving proteases, mitochondrial factors (e.g. , Bcl-2-related proteins, reactive oxygen species, mitochondrial membrane potential, opening of the permeability transition pore) or p53 participate in the modulation and execution of cell death. Effectors comprise oxidative stress, inflammatory processes, calcium toxicity and survival factor deficiency. Therapeutic agents are being developed to interfere with these events, thus conferring the potential to be neuroprotective. In this context, drugs with anti-oxidative properties, e.g., flupirtine, N-acetylcysteine, idebenone, melatonin, but also novel dopamine agonists (ropinirole and pramipexole) have been shown to protect neuronal cells from apoptosis and thus have been suggested for treating neurodegenerative disorders like AD or PD. Other agents like non-steroidal anti-inflammatory drugs (NSAIDs) partly inhibit cyclooxygenase (COX) expression, as well as having a positive influence on the clinical expression of AD. Distinct cytokines, growth factors and related drug candidates, e.g., nerve growth factor (NGF), or members of the transforming growth factor-beta (TGF-beta ) superfamily, like growth and differentiation factor 5 (GDF-5), are shown to protect tyrosine hydroxylase or dopaminergic neurones from apoptosis. Furthermore, peptidergic cerebrolysin has been found to support the survival of neurones in vitro and in vivo. Treatment with protease inhibitors are suggested as potential targets to prevent DNA fragmentation in dopaminergic neurones of PD patients. Finally, CRIB (cellular replacement by immunoisolatory biocapsule) is an auspicious gene therapeutical approach for human NGF secretion, which has been shown to protect cholinergic neurones from cell death when implanted in the brain. This review summarises and evaluates novel aspects of anti-apoptotic concepts and pharmacological intervention including gene therapeutical approaches currently being proposed or utilised to treat neurodegenerative diseases.
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PMID:Apoptosis modulators in the therapy of neurodegenerative diseases. 1106 Jul 7

The delta opioid peptide [D-Ala2, D-Leu5]enkephalin (DADLE) has been reported to block the neurotoxicity induced by multiple administrations of a moderate dose of methamphetamine (METH). We examined in this study if DADLE might block the neurotoxicity caused by a single high dose of METH in CD-1 mice. The levels of dopamine transporter (DAT), tyrosine hydroxylase (TH), major biogenic amines including DA, 5-hydroxytryptamine (5-HT), and their metabolites were examined. In addition, since the tumor suppressor p53 has been implicated in the neurotoxicity of METH, this study also examined the levels of p53 mRNA and protein affected by METH and DADLE. METH (25 mg/kg, i.p.) caused significant losses of DAT, TH, DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-HT in the striatum within 72 h. The administration of a single dose of DADLE (20 mg/kg, i.p., 30 min before METH) caused a complete blockade of all losses induced by METH except for that of the DA content (a approximately 50% blockade). DADLE did not affect the changes of rectal temperature induced by the administration of the high dose of METH. METH increased p53 mRNA in the striatum and the hippocampus of CD-1 mouse. DADLE abolished the p53 mRNA increase caused by METH. METH tended to increase the p53 protein level at earlier time points. However, METH significantly decreased the p53 protein level by about 30% at the 72-h time point. DADLE blocked both the increase of p53 mRNA and the decrease of p53 protein caused by METH. These results demonstrate a neuroprotective effect of DADLE against the neuronal damage and the alteration of p53 gene expression caused by a single high dose of METH. The results also indicate an apparent discordance between the protein level of p53 and the neurotoxicity caused by a high dose of METH. Synapse 39:305-312, 2001. Published 2001 Wiley-Liss, Inc.
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PMID:Delta opioid peptide [D-Ala2, D-Leu5]enkephalin causes a near complete blockade of the neuronal damage caused by a single high dose of methamphetamine: examining the role of p53. 1116 80

One week after intranigral injection of thrombin resulted in a dose-dependent loss of dopaminergic neurons (20-78%) in the rat substantia nigra (SN), as evidenced by tyrosine hydroxylase (TH) immunohistochemistry. This cell death was accompanied by localization of terminal deoxynucleotidyl transferase-mediated fluorecein UTP nick end labeling (TUNEL) staining within dopaminergic neurons, activation of caspase-3 and attenuation of dopaminergic neuronal cell death in the SN by the caspase inhibitor (zVAD-fmk), indicative of apoptosis. Furthermore, Western blot analyses and double-immunofluorescent staining showed activation of c-Jun N-terminal kinase (JNK) and p53, and a localization of p53 in the dopaminergic neurons in the SN after thrombin, respectively. Intriguingly, Western blot analyses demonstrated significant down-regulation of Bcl-2 protein, but no alteration in Bax protein expression in the SN after thrombin. Consistent with in vivo data, degeneration of dopaminergic neurons and colocalization of TUNEL and TH were observed in mesencephalic cultures, following treatment with thrombin. Cell death was almost completely abolished by the thrombin-specific inhibitor, hirudin. Thrombin receptor-activating peptides (TRAP-6 and-14) did not mimic the effects of thrombin, even at much higher (1,000 to 2,000-fold) concentrations, although expression of protease-activated receptor-1 (PAR-1) mRNA was detected using RT-PCR. Morphological evidence and molecular events in vivo and in vitro collectively suggest that thrombin induces apoptosis in dopaminergic neurons via non-PAR-1 receptors.
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PMID:Thrombin induces nigral dopaminergic neurodegeneration in vivo by altering expression of death-related proteins. 1457 41

Genetic engineering of neurotransmitter metabolic routes is important for the development of neurotransmitter-producing cells for the ex vivo gene therapy of many CNS diseases. Human neural stem cells (hNSCs) are excellent candidates to serve this role, but, for the case of Parkinson's disease, the cells do not normally express the rate-limiting dopamine (DA) synthesis enzyme tyrosine hydroxylase (TH), and are not equipped with the detoxifying mechanisms needed to prevent the neurotoxicity associated with the DA phenotype. In this study we have examined the capacity of hNSCs for ectopic expression of human TH. High-level TH expression (from viral promoters) leads to growth arrest and hNSC death (associated with an increase in p53 expression and nuclear fragmentation), which can be counteracted by treatment with a pan-caspase inhibitor. As a consequence, stable TH-expressing hNSC sublines could not be derived using viral promoters. In contrast, moderate TH expression (from a human housekeeping promoter, polyubiquitin gene), allows for stable TH+ subclone derivation, seemingly originating from low-expressing cells. Our results are thus compatible with the view that stable TH-expressing hNSC lines can be generated if TH expression levels are kept at a moderate level, and that the goal normally set of aiming at high-level TH expression may need to be reconsidered. These results may be relevant for the generation of TH/DA-producing human neural cells for in vitro and neurotransplantation research in Parkinson's disease.
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PMID:Low-level tyrosine hydroxylase (TH) expression allows for the generation of stable TH+ cell lines of human neural stem cells. 1496 74


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