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 molecular biology underlying the development of highly malignant peripheral nerve sheath tumors (MPNSTs) remains mostly unknown. In the present study, the expression pattern of 10 selected cell cycle components is investigated in a series of 15 MPNSTs from patients with (n = 9) or without (n = 5) neurofibromatosis type 1 (NF1). Thirteen tumors did not express the cyclin-dependent kinase inhibitor, p16(INK4A), an observation that was related to homozygote gene deletions in three tumors, heterozygote deletions in five, and gross gene rearrangements in five. The absence of protein expression in the tumors with one seemingly intact allele was not caused by promoter hypermethylation of p16(INK4A) or p14(ARF). All tumor samples expressed normal sized RB1, cyclin D3, CDK2, CDK4, p21(CIP1), and p27(KlP1) proteins, and only a single tumor showed an aberrant protein band for one of these proteins, p21(CIP1). Cyclin D1 was absent in four tumors; all except one tumor showed expression of TP53 protein, and three of nine MPNSTs had expression of normal-sized MDM2. In conclusion, this study shows that the vast majority of MPNSTs had gross rearrangements of the p16(INK4A) gene, explaining the absence of the encoded protein in the same tumors. The level of expression was equally distributed between the familial (NF1) and sporadic cases, although it should be noted that the 2 cases with p16(INK4A) expression were sporadic. The data imply that the complete absence of p16(INK4A) is sufficient for activation of the cell cycle in most MPNSTs; thus, it is not necessary for tumor proliferation to further stimulate the cycle through alteration of other central components.
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PMID:Expression patterns of cell cycle components in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors. 1571 87

Familial breast cancers that are associated with BRCA1 or BRCA2 germline mutations differ in both their morphological and immunohistochemical characteristics. To further characterize the molecular difference between genotypes, the authors evaluated the expression of 37 immunohistochemical markers in a tissue microarray (TMA) containing cores from 20 BRCA1, 14 BRCA2, and 59 sporadic age-matched breast carcinomas. Markers analyzed included, amog others, common markers in breast cancer, such as hormone receptors, p53 and HER2, along with 15 molecules involved in cell cycle regulation, such as cyclins, cyclin dependent kinases (CDK) and CDK inhibitors (CDKI), apoptosis markers, such as BCL2 and active caspase 3, and two basal/myoepithelial markers (CK 5/6 and P-cadherin). In addition, we analyzed the amplification of CCND1, CCNE, HER2 and MYC by FISH. Unsupervised cluster data analysis of both hereditary and sporadic cases using the complete set of immunohistochemical markers demonstrated that most BRCA1-associated carcinomas grouped in a branch of ER-, HER2-negative tumors that expressed basal cell markers and/or p53 and had higher expression of activated caspase 3. The cell cycle proteins associated with these tumors were E2F6, cyclins A, B1 and E, SKP2 and Topo IIalpha. In contrast, most BRCA2-associated carcinomas grouped in a branch composed by ER/PR/BCL2-positive tumors with a higher expression of the cell cycle proteins cyclin D1, cyclin D3, p27, p16, p21, CDK4, CDK2 and CDK1. In conclusion, our study in hereditary breast cancer tumors analyzing 37 immunohistochemical markers, define the molecular differences between BRCA1 and BRCA2 tumors with respect to hormonal receptors, cell cycle, apoptosis and basal cell markers.
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PMID:Phenotypic characterization of BRCA1 and BRCA2 tumors based in a tissue microarray study with 37 immunohistochemical markers. 1577 May 21

Benzene toxicity has long been thought to be due to its metabolites including reactive oxygen species (ROS). However, the major toxicological effect of benzene in wild-type mice carrying normal alleles of the p53 gene appears to be the significant perturbation of cell cycle regulation, possibly via an indirect signaling pathway. Other prominent genotoxic cellular damage can occur in the absence of cell cycle arrest in p53 gene deficiency. The suppression of cell cycle is clearly detected using a tool for stem-cell-specific cell cycle observation by the BU-UV method. Cells (including hemopoietic progenitor cells) in S-phase are labeled in vivo with bromodeoxyuridine (BrdU) and then exposed to near-ultraviolet (UV) light to kill cells that incorporated BrdU. The target fraction, the S-phase, is then evaluated on the basis of decreased numbers of hemopoietic colonies formed in assays such as for granulomacrophage colony-forming units (CFU-GM). Benzene toxicity was found to be more prominent in the primitive stem-cell compartment, as first suggested more than 20 years ago. Interestingly, when one examines the stem-cell-specific steady-state gene expression profiling, several key genes associated with benzene exposure are specifically identified, including CYP2E1. Benzene toxicity was found to be mediated by aryl hydrocarbon receptor (AhR) at an expression level; thus, the effect of benzene can be detected in nature at lower levels in the stem-cell compartment than expected. Alterations in gene expression profiles compared with those in steady-state gene expression profiles in the stem-cell compartment may elucidate the mechanism underlying benzene toxicity. Functional gene expressions after benzene exposure are not always detected, because their phenotypic expressions are often masked by the balance of expression of genes participating in various pathways of homeostasis, for example, p53. Thus, the actual expressions of the above-mentioned cell cycle-related genes may not be clearly detected. However, when one examines the genes after benzene exposure without p53 gene participation (i.e., p53 was knocked out), various cell cycle-related genes expressed during and after benzene exposure are identified, such as cyclin B1, cyclin D3 and growth hormone in the bone marrow. Since age-related impairments of p53 gene function in somatic cells are known, the possible alteration of those genes would be based not only on a theoretical model, but possible risks posed on the elderly should also be taken into consideration.
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PMID:p53-dependent gene profiling for reactive oxygen species after benzene inhalation: special reference to genes associated with cell cycle regulation. 1593 13

Cyclin D3 deregulation has recently been reported in bladder cancer but its prognostic significance remains uncertain. A cohort of 159 patients with stage Ta or T1 primary bladder tumours was investigated to determine the significance of cyclin D3 expression in association with other G1-S phase regulators of the cell cycle (p53, p21Waf1, p27kip1, cyclin D1), including tumour proliferation (ki67-MIB1); its association with conventional clinicopathological parameters; and the relationship between cyclin D3 and loss of heterozygosity (LOH) at the 9p21 (p16INK4a locus) chromosome region. The end point of the study was progression-free survival. Cyclin D3, other G1-S phase regulators, and tumour proliferation were investigated by immunohistochemistry and measured by the grid-counting method. To validate the immunohistochemical expression, cyclin D3 was additionally assessed by western blotting in selected cases. LOH at the 9p21 chromosome region (marker D9S171) was assessed in 125 cases using an AB Prism 310 genetic analyser and a set of microsatellite fluorescence-labelled primers. Cyclin D3 overexpression was related to larger tumour size (>5 cm; p < 0.0001) and high tumour proliferation (>10%; p = 0.025). Mean cyclin D3 expression increased with 2004 WHO grading categories in stage Ta (p = 0.035, ANOVA) and stage T1 (p = 0.047, t test) tumours. Cyclin D3 was not related to other clinicopathological parameters, G1-S phase modulators, or 9p21 LOH. Cox's multivariate analysis selected cyclin D3 as an independent predictor of progression-free survival (p = 0.0012, relative risk (RR) = 5.2366) together with tumour size (p = 0.0115, RR = 4.4442) and cyclin D1 (p = 0.0065, RR = 3.3023). Cyclin D3 expression had the highest risk ratio. Our results suggest that expression of cyclin D3 is relevant to the progression-free survival of patients with Ta/T1 bladder carcinomas.
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PMID:Cyclin D3 expression in primary Ta/T1 bladder cancer. 1648 99

Activation of c-jun N-terminal kinase (JNK) through c-kit-mediated phosphatidylinositol 3 (PI3) and Src kinase pathways plays an important role in cell proliferation and survival in mast cells. Gain-of-function mutations in c-kit are found in several human neoplasms. Constitutive activation of c-kit has been observed in human mastocytosis and gastrointestinal stromal tumor. In the present study, we demonstrate that an anthrapyrazole SP600125, a reversible ATP-competitive inhibitor of JNK inhibits proliferation of human HMC-1 showed constitutive activation of JNK/c-Jun, and the inhibitory effect of SP600125 on cell proliferation was associated with cell cycle arrest at the G1 phase and apoptosis accompanied by the cleavage of caspase-3 and PARP. Caspase-3 inhibitor Z-DEVD-FMK almost completely inhibited SP600125-induced apoptosis of HMC-1 cells. In contrast, caspase-9 inhibitor Z-LEHD-FMK failed to block SP600125-induced apoptosis. Following Sp600125 treatment, down-regulation of cyclin D3 protein expression, but not p53 was also observed. Thus, JNK/c-Jun is essential for proliferation and survival of HMC-1 cells. The results obtained from the present study suggest the possibility that JNK/c-Jun may be a therapeutic target in diseases associated with mutations in the catalytic domain of c-kit.
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PMID:Growth suppression of human mast cells expressing constitutively active c-kit receptors by JNK inhibitor SP600125. 1692 20

SARS-CoV 3a is a structural protein, mainly localizing to Golgi apparatus and co-localizing with SARS-CoV M in co-transfected cells. Here we observed that transient expression of 3a inhibited cell growth and prevented 5-bromodeoxyuridine incorporation, suggesting that 3a deregulated cell cycle progression. Cell cycle analysis demonstrated that 3a expression was associated with blockage of cell cycle progression at G1 phase in HEK 293, COS-7, and Vero cells 24-60 h after transfection. Mutation analysis of 3a revealed that C-terminal region (176 aa approximately 274 aa), including a potential calcium ATPase motif, was essential for induction of cell cycle arrest. Topological analysis showed that 3a predominantly located in Golgi apparatus, with its N-terminus residing in the lumen (Nlum) and C-terminus in the cytosol (Ccyt). Analyzing the cellular proteins involving in regulation of cell cycle progression, we demonstrated that 3a expression was correlated with a significant reduction of cyclin D3 level and phosphorylation of retinoblastoma (Rb) protein at Ser-795 and Ser-809/811, not with the expression of cyclin D1, D2, cdk4, and cdk6 in 293 cells. Increases in p53 phosphorylation on Ser-15 were observed in both SARS-CoV M and 3a transfected cells, suggesting that it might not correlate with the 3a-induced G0/G1 phase arrest. The reduction of cyclin D3 level and phosphorylation of Rb were further confirmed in SARS-CoV infected Vero cells. These results indicate that SARS-CoV 3a protein, through limiting the expression of cyclin D3, may inhibit Rb phosphorylation, which in turn leads to a block in the G1 phase of the cell cycle and an inhibition of cell proliferation.
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PMID:G1 phase cell cycle arrest induced by SARS-CoV 3a protein via the cyclin D3/pRb pathway. 1741 32

Down-regulation of p53 expression has been found in a broad range of human cancers and cell proliferation disorders, indicating that p53 plays a key role in cell cycle regulation and tumor suppression. In our current study, we transfected human embryonic lung fibroblast (HELF) cells with pcDNA3-wild-type p53 (pcDNA3-wtp53) plasmid, or pcDNA3-H179Y-mutated p53 (pcDNA3-mtp53) plasmid that mimics the mutation found in some human lung tumors, and further studied the role of p53 in the regulation of cell proliferation. Over expression of wild-type p53 caused cell cycle arrest at G1 phase with reduced cell size, decreased expression of cyclin D3, cyclin E, Cdk2 and Cdk4, and increased expression of p21. In contrast, over expression of H179Y-mutant p53 promoted G1 to S phase transition with enlarged cell size and increased cyclin A1 and Cdk4 expression in HELF cells. These results indicate that mutation at the p53 H179Y residue up-regulates cyclin A1 and Cdk4 expression, and promotes HELF cell proliferation.
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PMID:The over-expression of p53 H179Y residue mutation causes the increase of cyclin A1 and Cdk4 expression in HELF cells. 1753 Jan 87

This study, using tissue microarrays, aimed at the immunomorphologic profiling of nonsmall cell lung cancer (NSCLC) cases to reveal clinically relevant disease groups and biomarkers associated with patients' survival and tumor progression including brain metastatic potential. Donor tissue blocks were form 59 patients, including 33 primary tumors without distant metastasis and 26 brain metastatic primary tumors as well as the brain metastases. Sections were immunostained for 29 markers targeting molecules of cell adhesion, cell growth, cell cycle, and apoptosis regulation. beta-Catenin expression was the only independent prognostic marker associated with better outcome. Elevated expression of collagen XVII, CD44v6, and caspase-9, and the reduced production of beta-catenin and cellular apoptosis susceptibility protein were significantly associated with the metastatic potential of primary NSCLC. Expression of positive cell cycle regulators cyclin D1 and cyclin D3 was also increased in metastatic primary tumors. Metastatic tumor progression into the brain was accompanied by prominent p16, syndecan-1, p53 (DO7), and caspase-3 protein levels. Hierarchical clustering of complex immunoprofiles based on the differentially expressed markers grouped NSCLCs of the poorest outcome with high correlation including 2/3 of brain metastases of mixed histology. The brain metastatic potential of NSCLCs may be linked to the elevated levels of cyclinD1, cyclinD3, p16, p53, caspase-3, caspase-9, CD44v6, and collagen XVII and the down-regulation of beta-catenin and cellular apoptosis susceptibility protein. Unsupervised immunoprofiles based on differentially expressed biomarkers may help selecting lung cancers with aggressive behavior.
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PMID:Immunophenotypic profiling of nonsmall cell lung cancer progression using the tissue microarray approach. 1753 3

The marine natural chamigrane-type sesquiterpenoid, dactylone, is closely related to secondary metabolites of some edible species of red algae. In the present study, the effect of dactylone was tested on the mouse skin epidermal JB6 P+ Cl41 cell line and its stable transfectants as well as on several human tumor cell lines, including lung (H460), colon (HCT-116), and skin melanomas (SK-MEL-5 and SK-MEL-28). This natural product was effective at nontoxic doses as a cancer-preventive agent, which exerted its actions, at least in part, through the inhibition of cyclin D3 and Cdk4 expression and retinoblastoma tumor suppressor protein (Rb) phosphorylation. The inhibition of these cell cycle components was followed by cell cycle arrest at the G1-S transition with subsequent p53-independent apoptosis. Therefore, these data showed that application of dactylone and related compounds may lead to decreased malignant cell transformation and/or decreased tumor cell proliferation.
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PMID:Dactylone inhibits epidermal growth factor-induced transformation and phenotype expression of human cancer cells and induces G1-S arrest and apoptosis. 1757 61

Abnormal expression of cell cycle regulators may contribute to malignant transformation. However, the clinical significance of the expression of cyclin D3 in ovarian cancer remains undefined. We therefore conducted a retrospective investigation to address the role of this cell-cycle protein in this tumor. In our study, paraffin-embedded tissue from 109 nonbenign epithelial ovarian tumors, including 17 tumors of low malignant potential and 92 primary adenocarcinomas, was stained immunohistochemically for cyclin D3. Most of the cases had previously been stained for pRb, p21Cip1, p27Kip1, p53, and Ki-67 antigen. Expression of cyclin D3 was correlated with clinicopathologic features, the expression of other cell cycle regulators, and postoperative survival of patients. Cyclin D3 levels were significantly higher in tumors of low malignant potential than in adenocarcinomas (P = 0.0002). In the latter group, cyclin D3 expression decreased with increasing grade (P = 0.0004) and advancing stage (P = 0.0315). Cyclin D3 expression positively correlated with pRb, p21Cip1, and p27Kip1 levels (P = 0.0021; P = 0.0036; P < 0.0001, respectively) and negatively with p53 and Ki-67 (P = 0.0003; P < 0.0001). Absent cyclin D3 expression was an important indicator of poor survival in univariate analysis in the entire cohort (P > 0.00010) and in the platinum-treated patients (P = 0.001) and in multivariate analysis (P = 0.044). Our results demonstrate that absent or decreased cyclin D3 expression is adversely related to several clinicopathologic indicators of aggressiveness in ovarian adenocarcinomas and is combined with a better prognosis, suggesting that cyclin D3 may have a biological role distinct from that of other G1 cyclins which is possibly regulated through interaction with other cell cycle genes.
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PMID:Expression and prognostic significance of cyclin D3 in ovarian adenocarcinomas. 1788 91


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