UNIPROT:P04637 - FACTA Search

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Query: UNIPROT:P04637 (p53)
77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A prostatic smooth muscle cell line (PSMC1) was established from the dorsolateral prostate of p53 null mice. The cell line is nontumorigenic when inoculated subcutaneously, under the renal capsule or intraprostatically in syngeneic mice. These cells express alpha-smooth muscle actin (alpha-SMA), indicating their smooth muscle origin, and TGF-beta significantly enhances expression of alpha-SMA. The cells express both androgen receptor (AR) mRNA and protein, and respond mitogenically to physiological concentrations of androgens. PSMC1 cells produce significant amounts of TGF-beta, which stimulates growth by an autocrine mechanism. Dihydrotestosterone (DHT) increases proliferation of PSMC1 cells by promoting TGF-beta secretion. Considering the significant inhibitory effect of TGF-beta on prostatic epithelial cells and its stimulatory effect on the PSMC1 cells, we postulate that TGF-beta produced by prostatic smooth muscle cells may have a paracrine effect on the prostatic epithelium. We also postulate that TGF-beta may be involved in the etiology of benign prostatic hyperplasia (BPH) by stimulating excessive stromal proliferation. Line PSMC1 is the first reported androgen-responsive murine smooth muscle cell line. It will be useful for in vivo and in vitro experiments to study the mechanisms of androgen action on prostatic stroma and for delineating the interactions that occur between prostatic smooth muscle and epithelium that may lead to prostatic diseases such as BPH.
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PMID:Transforming growth factor-beta is an autocrine mitogen for a novel androgen-responsive murine prostatic smooth muscle cell line, PSMC1. 1105 12

Androgen-independent prostate cancer cells are remarkably resistant to therapeutic agents that work by triggering apoptosis via the caspase cascade. The recent sequencing of the entire genome of one of the most radiation-resistant organisms known, Deinococcus radiodurans, yields some insight into how prostate cancer cells might mount such resistance to apoptosis. Rather than being attributable to any one mechanism, the extreme radiation resistance of D. radiodurans appears to reflect the expression of a large number of different systems capable of preventing, repairing, or tolerating DNA damage and a very high degree of redundancy in these systems. Many molecular alterations that may influence the threshold for apoptosis have already been described in advanced prostate cancer; changes in bcl-2, p53, and the androgen receptor have been the most extensively studied. Current information is consistent with the concept that individual prostate cancer cells express multiple antiapoptotic mechanisms. This conclusion implies that it will not be possible to enhance cellular sensitivity to therapeutics that activate apoptosis by disabling just one target in a pathway, because other proteins are likely to be available to assume its function. Likewise, even elimination of a whole pathway may have little effect on sensitivity because cellular viability is protected by so many different mechanisms. However, where molecular changes have a phenotypic consequence, they offer a window of opportunity for the development of novel therapeutic strategies. One such example is a recently identified small organic compound that can inhibit p53 function and thus protect normal tissues against radiation-induced apoptosis without impairing killing of p53-deficient tumor cells.
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PMID:Resistance to apoptosis in prostate cancer cells. 1106 78

Male breast cancer is uncommon; so far, only 10 cases with chromosome banding analysis have been published. We report the cytogenetic findings of two invasive breast cancers in two Caucasian men lacking a history of familial breast cancer and more than 70 years of age. Both had ductal carcinomas with lymphangiosis carcinomatosa and positive lymph nodes at diagnosis. Strong expression of estrogen receptor, weak expression of progesterone receptor, and lack of expression of androgen receptor by both tumors were demonstrated by immunohistochemistry, as well as lack of expression of p53 and C-ERB-B-2. The karyotypes were 45 approximately 46,XY,-Y[4],-7[2],+8[2],t(8;12)(q21;q24)[3], del(9)(q22)[3],del(11)(p11p14)[5],del(18)(q21)[7], t(19;20)(p10;q10)[8] [cp13] and 61 approximately 69,XXXY,-Y[3], del(2)(p21)[4],del(3)(p22q26)[3],-4,-4[5],+5,+5[5], dic(5;11)(p14;q23)[3],del(6)(q23)[4],del(8)(p21)[3],-9[4],-11[4],+ i(12)(p10)[4],-16[3],del(17)([13)[5],del(18)(q21)[4],+19[5], +20[4][cp7], respectively. Although the available data on male breast cancer are still very limited, our findings confirm that gain of an X chromosome, loss of the Y chromosome, gain of chromosome 5, and loss of material from chromosomes 17 and 18 are nonrandom aberrations in male breast cancer. Trisomy 8, characteristic of ductal carcinomas, was found in one case.
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PMID:Karyotypic findings in two cases of male breast cancer. 1106 6

This review provides an overview of the literature on aspects of reproductive endocrinology wherein Asian men may differ from Caucasian, notably, prostatic neoplasm and the sensivity to pharmacological regimens of male contraception. Both genetic and environmental factors, such as nutrition, might be relevant. Asian men residing in Asia seem to be relatively protected from clinical prostatic neoplasm while the prevalence of preclinical prostatic neoplasm is not different. Migration to an area with a higher prevalence reduces this difference but does not undo it. With regard to prostatic neoplasm the following factors have been considered as relevant in Asian men: 1) a reduction in 5 alpha-reductase level, 2) decreased levels of androgenic ketosteroid precursors of 5 alpha-reduced androgen metabolites, 3) the decreased presence of a P53 mutation, 4) a higher CAG-repeat length of the androgen receptor, 5) a possible higher level of physical activity, 6) differences in sexual activity. Furthermore, Asian men respond to a higher degree with azoospermia in response to contraceptive steroids. Possible explanations offered for the more pronounced response to contraceptive steroids are: 1) differences in testicular structure and decreased spermatogenic potential, 2) an earlier and more marked suppression in LH secretion by exogenous androgens. The differences may be due to genetical and/or environmental factors influencing the peripheral testosterone metabolism. Dietary factors such as the higher intake of phytoestrogens in Asians might exert effects on 5 alpha-reductase activity and/or on sex hormone binding globulin (SHBG) levels, thus having an impact on the biological efficacy of circulating androgens.
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PMID:Differences in reproductive endocrinology between Asian men and Caucasian men--a literature review. 1122 31

Apocrine ductal carcinoma in situ (ADCIS) has been called a special type of ductal carcinoma in situ (DCIS) because the histologic grading is considered difficult using the classification schemes that have been proposed for common DCIS. However, ADCIS encompasses a spectrum of lesions with different morphologic aspects ranging from minimally atypical to overtly malignant. To define a classification scheme for ADCIS, 35 cases (22 pure and 13 associated with invasive carcinoma) were selected on the basis of conventional morphology on hematoxylin and eosin (H&E)-stained sections. Each case was assigned to 1 of 3 histologic grades (low, intermediate, and high) based on nuclear morphology and the presence of necrosis. In addition, the expression of hormone receptors p53, bcl-2, c-erbB-2, and Ki-67 was evaluated by immunohistochemistry, and the DNA ploidy was determined by image cytometry. Fifteen cases were classified as high histologic grade, 10 as low histologic grade, and the other 10 as intermediate grade. All but 4 cases, irrespective of grade, had the same hormonal immunophenotype: androgen receptor positivity (97.1%) and estrogen receptor and progesterone receptor negativity (94.3% and 97.1% respectively). Twenty-one cases (61.8%) showed p53 expression, and 47.1% of the cases were positive for c-erbB-2. The median positivity for Ki-67 was 5.2%. ADCIS has a unique morphologic and hormonal profile, distinct from common DCIS, deserving a specific classification. The proposed classification scheme allows for categorization of ADCIS according to the most important morphologic features already seen in common DCIS, ie, nuclear grade and necrosis. The expression of biologic markers other than hormonal receptors and bcl2 in ADCIS seems in general to be similar to that in common DCIS. Ki-67 and c-erbB-2 are expressed more frequently in intermediate and high histologic grade ADCIS.
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PMID:Apocrine ductal carcinoma in situ of the breast: histologic classification and expression of biologic markers. 1138 66

PC SPES (BotanicLab, Brea, California) an herbal supplement for patients with prostate cancer, is composed of 7 highly concentrated Chinese herbs and 1 US herb. It was developed in seeking positive attributes of Chinese and Western medicine for cancer treatment. Chemical standardization of this composition showed that baicalin is the most abundant active compound. Several reports on phase 2 clinical studies of PC SPES suggest that it is a well-tolerated active treatment for androgen-independent prostate cancer. In this report, data obtained from various laboratory experiments will be presented to elucidate the in vitro mechanism. Profound biologic effects of PC SPES on prostate cancer cells were observed on both androgen-dependent (LNCap) and androgen-independent (DU-145) cell lines. These effects include the following: (1) induction of cell apoptosis and cell cycle modulation; (2) inhibition of cell proliferation; (3) downregulation of bcl-2, bcl-6, proliferating cell nuclear antigen, and prostate-specific antigen proteins; (4) downregulation of androgen receptor (AR); and (5) upregulation of p53, bax, and p21 proteins. Concurrent animal studies using 2 different models, Copenhagen rats and nude mice, confirmed a dose-dependent suppressive effect of PC SPES on tumor volumes and tumor progression. Our results show that the cytotoxic and cytostatic properties of PC SPES are not entirely dependent on the presence of AR. The antitumor mechanism of PC SPES is complex. It involves multiple metabolic pathways, such that the whole extract acts on redundant mechanisms, which otherwise will permit cell survival if a single-target agent is used.
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PMID:In vitro mechanism of PC SPES. 1150 43

C-cell hyperplasias are normally multifocal in multiple endocrine neoplasia type 2A. We compared clonality, microsatellite pattern of tumor suppressor genes, and cellular kinetics of C-cell hyperplasia foci in each thyroid lobe. We selected 11 females from multiple endocrine neoplasia type 2A kindred treated with thyroidectomy due to hypercalcitoninemia. C-cell hyperplasia foci were microdissected for DNA extraction to analyze the methylation pattern of androgen receptor alleles and microsatellite regions (TP53, RB1, WT1, and NF1). Consecutive sections were selected for MIB-1, pRB1, p53, Mdm-2, and p21WAF1 immunostaining, DNA content analysis, and in situ end labeling. Appropriate tissue controls were run. Only two patients had medullary thyroid carcinoma foci. Nine informative C-cell hyperplasia patients showed germline point mutation in RET, eight of them with the same androgen receptor allele preferentially methylated in both lobes. C-cell hyperplasia foci showed heterogeneous DNA deletions revealed by loss of heterozygosity of TP53 (12 of 20), RB1 (6 of 14), and WT1 (4 of 20) and hypodiploid G0/G1 cells (14 of 20), low cellular turnover (MIB-1 index 4.5%, in situ end labeling index 0.03%), and significantly high nuclear area to DNA index ratio. MEN 2A (germline point mutation in RET codon 634) C-cell hyperplasias are monoclonal and genetically heterogeneous and show down-regulated apoptosis, findings consistent with an intraepithelial neoplasia. Concordant X-chromosome inactivation and interstitial gene deletions suggest clone expansions of precursors occurring at a point in embryonic development before divergence of each thyroid lobe and may represent a paradigm for other germline mutations.
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PMID:Germline RET 634 mutation positive MEN 2A-related C-cell hyperplasias have genetic features consistent with intraepithelial neoplasia. 1150 37

Prostate-specific antigen (PSA) is highly overexpressed in prostate cancer. One important regulator of PSA expression is the androgen receptor (AR), the nuclear receptor that mediates the biological actions of androgens. AR is able to up-regulate PSA expression by directly binding and activating the promoter of this gene. We provide evidence here that that this AR activity is repressed by the tumor suppressor protein p53. p53 appears to exert its inhibition of human AR (hAR) by disrupting its amino- to carboxyl-terminal (N-to-C) interaction, which is thought to be responsible for the homodimerization of this receptor. Consistent with this, p53 is also able to block hAR DNA binding in vitro. Our previous data have shown that c-Jun can mediate hAR transactivation, and this appears to result from a positive effect on hAR N-to-C interaction and DNA binding. Interestingly, c-Jun is able to relieve the negative effects of p53 on hAR transactivation, N-to-C interaction, and DNA binding, demonstrating antagonistic activities of these two proteins. Importantly, a p53 mutation found in metastatic prostate cancer severely disrupts the p53 negative activity on hAR, suggesting that the inability of p53 mutants to down-regulate hAR is, in part, responsible for the metastatic phenotype.
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PMID:p53 represses androgen-induced transactivation of prostate-specific antigen by disrupting hAR amino- to carboxyl-terminal interaction. 1150 17

Salivary duct carcinoma (SDC) is a rare high-grade aggressive neoplasm that manifests close histologic features with invasive ductal carcinoma of the breast (IDC). In contrast to SDC, extensive molecular studies have been performed on IDC and led to the identification of certain biological markers. To investigate the underlying molecular and biologic characteristics of SDC, we performed molecular analyses using microsatellite markers on chromosomal arms 6q, 16q, 17p, and 17q, DNA flow cytometry and immunohistochemical staining for androgen receptor (AR) and p53 expression on 28 examples of these tumors in comparison to 24 IDC cases. Our results show that generally similar allelic alterations, elevated p53 and androgen receptor expressions, and high frequency of DNA aneuploidy are manifested in both SDCs and IDCs. Differences at certain markers on 6q, 17p and 17q chromosomal loci, however, were observed between the two entities. Certain loci on 6q were more frequently altered in SDC than IDC which loci on chromosomes 17p and q arms were more seen in IDCs than SDCs. The majority of SDCs had high AR expression while most of IDCs were AR negative. Our study indicates that: i) SDC may share some genetic alterations with IDC, ii) high AR expression in SDC may play a role in tumor progression, and iii) p53 overexpression and DNA aneuploidy in both entities reflect their aggressive behavior.
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PMID:Molecular and biomarker analyses of salivary duct carcinomas: comparison with mammary duct carcinoma. 1156 68

The study of the prognostic criteria of hormone-resistant prostatic cancer (PC) by specifying expression of androgen receptor protein as well as Bcl-2 and p53 proteins, apoptosis regulators, has demonstrated that tumor cells of hormone-sensitive and hormone-resistant PC forms have different variants of immunophenotype. Hormone-resistance is typical for tumors from urothelial, basal and neuroendocrine PC cells, glandular epithelium cells which lost androgen receptors (AR) and tumors consisting of cells which retain AR but simultaneously express Bcl-2 and/or p53 genes. The discovery of androgen-resistant cancer from glandular epithelium which has immunophenotype characteristics of a hormone-dependent tumor indicates the existence of other mechanisms of protection against apoptosis. The development of hormone-resistant cancer 2.5-3 years after hormonal therapy is associated with changes in immunophenotype of tumor cells. They become Bcl-2- and/or p53-positive while part of them lose AR. Thus, immunophenotype of tumor cells may serve a prognostic marker of hormonal resistance of the tumor and dictate the treatment policy.
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PMID:[Hormone-resistant epithelial cancer of the prostate]. 1156 31

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