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 availability of antibodies which recognise p53 protein in paraffin-embedded tissue has created the opportunity to use immunohistochemistry to study the expression of p53 in a wide variety of clinical material. In this paper we have investigated the relationship between the type of fixative and the pattern of p53 staining in mammary carcinoma. Optimal results were obtained from breast tissue fixed in phenol formol saline, methacarn or cold formol saline with positive staining for stabilised p53 protein occurring in 69/95 (73%) cases studied. Care must be taken in the interpretation of these results since positive staining for p53 protein is not always indicative of mutation of the p53 gene. Furthermore, a range of staining patterns is seen in mammary carcinomas, making interpretation difficult. Assessment of staining needs to be standardised in order that different studies can be compared. However, in breast carcinoma, p53 immunohistochemistry appears to give information relating to tumour grade and, independently, to prognosis.
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PMID:Problems with p53 immunohistochemical staining: the effect of fixation and variation in the methods of evaluation. 750 24

DNA from archival Papanicolaou stained smears was successfully amplified using the polymerase chain reaction (PCR) to see if it could be used for retrospective genome studies such as detection of the presence of human papilloma virus (HPV) and changes in p53 gene expression. DNA was isolated and purified by treatment with proteinase K, phenol/chloroform, and isoamyl alcohol. Segments of the human beta actin and TGF beta 1 gene were amplified by PCR. Of all stains used in the preparation of Papanicolaou smears, only eosin was detectable as a greenish band in ethidium bromide treated DNA gels under ultraviolet illumination.
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PMID:PCR amplification of DNA from stained cytological smears. 768 6

DNA was extracted from unstained 5-microns sections of neutral buffered 10% formalin-fixed paraffin-embedded tissue by proteinase K digestion without detergents followed by boiling, proteinase K digestion with ionic detergents with and without phenol chloroform extraction and ethanol precipitation, sonication with proteinase K followed by boiling, or boiling alone. Serial 1:10 dilutions of the extracted DNA were subject to polymerase chain reaction (PCR) amplification of a 255-bp portion of the p53 gene. Digestion with proteinase K without ionic detergents followed by boiling (without phenol chloroform extraction) gave the best yield, enabling visualization of ethidium bromide-stained PCR product from a DNA dilution corresponding to 0.1 mm2 of tissue containing of the order of 10(3) nuclear profiles. Proteinase K digestion with detergents followed by phenol-chloroform extraction was no more effective than simple boiling. Although the success of PCR from preserved tissue will vary with the fixative and size of the amplified fragment, DNA extracted with this optimized method can be used for identification of viruses, loss of heterozygosity, and immunoglobulin gene rearrangements in paraffin-embedded tissue without radioisotopes.
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PMID:Comparison of methods for extracting DNA from formalin-fixed paraffin sections for nonisotopic PCR. 886 37

A characteristic shared by a diverse group of myelotoxic compounds and leukaemogens is the ability to act synergistically with granulocyte-macrophage colony stimulating factor (GM-CSF) in increasing clonogenic response. Pretreatment of murine or human bone marrow cells with the benzene metabolite, hydroquinone, but not phenol, catechol or trans, trans-muconaldehyde, results in a selective enhancement of GM-CSF but not an interleukin-3 (IL-3)-mediated clonogenic response. Clonal enhancement is preserved and magnified in enriched populations of CD34+ cells (> 95% purity), suggesting an intrinsic effect on haematopoietic progenitor cell (HPC) recruitment rather than a secondary effect involving accessory cytokines. Clonogenic enhancement of murine HPCs is not accompanied by alterations in GM-CSF receptor expression or ligand affinity and appears to be mediated via a p53-independent mechanism. These observations suggest that hydroquinone treatment alters recruitment and differentiation in a primitive subpopulation of CD34+ cells and are consistent with a role for altered stem cell differentiation in the development of chemically induced myelodysplasias.
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PMID:The effects of benzene and other leukaemogenic agents on haematopoietic stem and progenitor cell differentiation. 898 53

We report a protocol which can analyze DNA by the dideoxy method. First, we prepared DNA from paraffin specimen of colon cancer and normal tissue by the method using proteinase and phenol. Polymerase chain reaction (PCR) was performed as follows. The primers used were oligonucleotides corresponding to the sequence of exon 5 on p53. An initial denaturing step was carried out at 94 degrees C for 2 min. Products were amplified for 40 cycles at 94 degrees C for 1 min, 60 degrees C for 1 min, and 72 degrees C for 1 min. Specific PCR products derived from p53 gene were purified. Protocol for the PCR-sequencing reaction: The reaction mixture was divided into four 4 microliters fraction. Each fraction was mixed with 2 microliters of NTP solution including non-RI dideoxynucleotides (TOYOBO). PCR was carried out as follows: an initial denaturing step at 94 degrees C for 1 min, then 30 cycles at 94 degrees C for 1 min, 60 degrees C for 1 min, and 72 degrees C for 1 min. Prior to loading in a denaturing 8% polyacrylamide-6M Urea gel, the samples were heated to 94 degrees C for 2 min then quickly chilled in ice-water. Electrophoresis was carried out at 1000V for 3hr and transcribed to a nylon membrane. The ladders of DNA were obtained by Non-RI Detection Kit (TOYOBO). We determined the sequence of 167 nucleotides. Results indicated that the point mutations in DNA could be easily detected.
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PMID:[Detection of nucleotide mutation by direct sequencing method using non-radio isotopic marker]. 925 14

We have investigated the influence of three structurally different but functionally related compounds [1, 10 ortho-phenanthroline (phenanthroline), Rifampicin and aurin tricarboxylic acid (ATA)] on the rate and the extent of proliferation of progesterone-responsive T47D human breast cancer cells. These compounds have previously been used in this laboratory and have been shown to modulate properties of nucleic acid binding proteins. Because p53 and the progesterone receptor (PR) are both DNA binding proteins that appear to regulate proliferation of breast cells, alterations in T47D cell p53 and PR levels were examined to determine their relevance in cell proliferation. T47D cells were grown in the absence of phenol red and in the presence of 5% fetal calf serum with or without charcoal stripping in the presence of the inhibitors. The rate of proliferation of cells grown in Rifampicin containing medium exhibited nearly 70% inhibition. Phenanthroline, a known metal chelator, was an effective inhibitor of proliferation at 3 mM reducing the cell number by more than 75%. ATA (0.24-2.4 micrograms/ml) inhibited the growth of the cells by nearly 50%. Analysis of the mechanism of action of these compounds revealed that treatment with these compounds caused specific changes in the molecular composition of T47D cell PR. Whereas ATA caused increased stability of PR isoforms, Rifampicin induced a upshift in the mobility of PR in SDS gels-a phenomenon associated with hyperphosphorylation of steroid receptors (SRs). Phenanthroline treatment (> 2 mM) caused a complete down-regulation of PR and the tumor suppressor protein, p53. The downregulation of p53 paralleled the changes in the molecular composition of PR. We propose that the inhibition of T47D cell proliferation by phenanthroline, Rifampicin and ATA results from a number of cellular changes that include regulation of p53 and PR.
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PMID:Inhibition of proliferation of T47D human breast cancer cells: alterations in progesterone receptor and p53 tumor suppressor protein. 935 37

Meat cooked at high temperatures contains mutagens and carcinogens known as heterocyclic amines (HCA). Cooking temperature and time determine the amount of HCA produced. The present study examined the DNA of liver, colon, and stomach from rats fed a high level of HCA for 27 weeks. Male Sprague-Dawley rats were fed a high-fat AIN-76A-based diet containing 60% by weight cooked beef containing a high level of HCA, especially 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP, 72 ng/g cooked beef), the most abundant HCA in cooked meat products. At the end of 27 weeks the rats were terminated, and small portions of liver, colon, and stomach were quick-frozen in liquid nitrogen. The DNA was isolated from the thawed tissue by phenol-chloroform extraction, and the genomic DNA was analyzed for the presence of PhIP adducts by 32P-postla-beling analysis. The DNA was also used in polymerase chain reactions to amplify the rat p53 and Apc genes, then direct dye-terminator DNA sequencing was carried out. Results showed no PhIP adducts in any tissue. In addition, no signature p53 or Apc gene mutations were seen in colon or stomach DNA. These results indicate that the high level of HCA present in a diet of well-cooked meat does not cause 1) persistent PhIP adducts similar to those produced by feeding pure PhIP at high doses or 2) p53 and Apc gene mutations in nontumor tissue.
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PMID:Absence of PhIP adducts, p53 and Apc mutations, in rats fed a cooked beef diet containing a high level of heterocyclic amines. 963 95

The tumor suppressor gene p53 encodes a nuclear phosphoprotein which is critical for cell cycle control and prevention of uncontrolled cell proliferation that can lead to cancer. Previous studies have shown that cells respond to DNA damage by increasing their levels of p53, which then acts to prevent replication of damaged DNA. This study examined the effects on p53 protein levels of several different categories of chemical carcinogens. N-Methyl-N'-nitro-nitrosoguanidine and N-ethyl-N-nitrosourea, two direct-acting genotoxic (DNA-reactive) carcinogens, caused p53 induction as early as 2 h following treatment, with peak increases within 4-12 h. Aflatoxin B1 and 2-acetylaminofluorene, indirect-acting genotoxic carcinogens, caused a later induction of p53, with the peak increase appearing between 16 and 24 h following treatment. These observations demonstrate a correlation between p53 induction pattern and DNA damaging mechanism of genotoxins. Phenol, diethylstilbestrol and ethylacrylate also induced increases in cellular p53. The half-life of p53 protein was increased in cells treated with genotoxic agents. On the other hand, the epigenetic (non-DNA-reactive) carcinogens azathioprine and saccharin, as well as two substances generally considered to be non-carcinogens, dimethylsulfoxide and benzethonium chloride, had no effect on p53 protein levels of treated cells. Measurement of the cytotoxic effects of each of these chemicals led to the conclusion that p53 protein induction is not a general, non-specific consequence of the cytotoxic effect of these genotoxins. These results suggest that measurement of p53 protein induction may be an effective tool to identify environmental genotoxins.
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PMID:A new approach to identifying genotoxic carcinogens: p53 induction as an indicator of genotoxic damage. 993 68

The aim of this study was to evaluate the concordance between the presence of p53 mutations in breast carcinomas expressing the protein by immunohistochemistry. A series of 60 breast carcinomas was evaluated by immunohistochemistry using monoclonal antibodies against p53 protein (DO 7 and PAb 1801). Twenty cases classified as being positive for p53 according to the current approach (if 5% or more of neoplastic cells contained reaction product in the nucleus) were used for molecular studies. These cases were re-assessed semi-quantitatively using a scoring system based on intensity and percentage of stained cells. DNA was phenol-chloroform extracted from microdissected normal and tumour cells obtained from formalin-fixed, paraffin-embedded tissue sections. Mutations in the p53 gene were analysed by SSCP (single strand conformational polymorphism) with primers covering exons 2-3 to 11. Ten out of the 20 p53-positive cases presented mutations detected by SSCP analysis. Mutations have been found in several exons ranging from exon 4 to exon 10. We observed a positive relationship between the presence of mutations and immunohistochemical evaluation of p53 protein expression using a semiquantitative scoring system. All cases with more than 2/3 stained tumour cells and strong intensity of staining exhibited p53 mutations. At variance, no p53 mutations were found in cases with less than 1/3 stained tumour cells and moderate intensity of staining. Therefore, only the identification of positivity for p53 detected by immunohistochemistry did not always reflect the detection of p53 mutations in breast cancer, however the use of a semi-quantitative approach seems to be useful as an indicator of the presence of mutation.
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PMID:P53 in breast carcinomas: association between presence of mutation and immunohistochemical expression using a semiquantitative approach. 989 46

The human breast epithelial cell line, MCF-10A, derived from tissue from a woman undergoing a cutaneous mastectomy for fibrocystic breast disease, is negative for estrogen receptor expression, has undergone minimal genetic changes, retains many of the characteristics of normal breast epithelium and fails to exhibit growth in nude mice. When transfected with a functional copy of the estrogen receptor, both ER and MDM2 expression are negatively regulated by the presence of increasing concentrations of estradiol, as previously reported. We obtained the MCF-10A cell line from the American Type Culture Collection and confirmed that it was negative for ER expression. After approximately 20 passages under differing growth conditions, one subline was determined to be positive for ER expression. Growth of this ER-positive subline in phenol red-free media supplemented with charcoal-dextran stripped serum in the presence of nanomolar concentrations of estradiol failed to modulate ER and MDM2 expression, and induced expression of both pS2 and cathepsin D. Simultaneously with these observations, we observed that this subline, unlike the parent MCF-10A line, overexpressed P53 protein with a nuclear localization. Intermediate levels of the P53-inducible protein p21 WAF1/Cip1 were also detected in the ER-positive subline whereas levels of this protein in the parent subline were barely detectable, as measured by immunohistochemical methods. We conclude from these studies that ER expression and P53 alteration may constitute early steps in progression of malignant potential for breast cancer development.
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PMID:Spontaneous conversion to estrogen receptor expression by the human breast epithelial cell line, MCF-10A. 1020 82


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