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)

Resistance to chemotherapy commonly compromises the treatment of many advanced cancers. Evidence suggests a correlation between chemoresistance and more aggressive tumor growth, possibly through accumulation of additional genetic defects in drug-treated or resistant cells. To study this process in a human ovarian cancer model, we examined OVCAR-3 cells for acute sensitivity to cisplatin (cDDP) and subsequent emergence of drug-resistant clones following chronic cDDP exposure. Clonal cells (OVCAR-3/C-1) that displayed 20-fold reduced sensitivity to cisplatin but retained equivalent sensitivity to paclitaxel, as compared with the parental population, were isolated. The cDDP-resistant clone had growth kinetics similar to those of parental population, but when transplanted into the peritoneal cavity of nude mice, they acquired the ability to grow with the development of both ascites and solid tumor masses; such growth was not detectable after transplantation of the drug-sensitive parental cell line. C-1 cells had a p53 gene mutation (codon 266) that was not detected in the parental OVCAR-3 cell line, and infection of C-1 cells with p53-adenovirus (rAd-p53) caused greater apoptosis and gene transduction than that observed in the similarly infected parental population. rAd-p53 induced high levels of p21WAF1, p27Kip1, activated caspase 3 and apoptosis in C-1 cells, without causing major changes in bax or bcl-XL levels. Together, the results suggest that alterations in tumor growth and gene mutations characterize cDDP-resistance in OVCAR-3 cells, and viral replacement of one of these defective genes (p53) may provide an effective treatment for elimination of drug-resistant cells.
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PMID:Emergence of cisplatin-resistant cells from the OVCAR-3 ovarian carcinoma cell line with p53 mutations, altered tumorigenicity, and increased apoptotic sensitivity to p53 gene replacement. 1124 Jun 61

Cyclin D3 is the most widely expressed D-type cyclin and can be rate limiting for G1/S transition. To study the expression of cyclin D3 in non-Hodgkin lymphoma, samples from 198 previously untreated patients with lymphoma from a prospectively collected, population-based lymphoma registry were analyzed immunohistochemically for cyclin D3 expression. In 43 lymphomas (21.7%), cyclin D3 was overexpressed. T-cell lymphomas more frequently overexpressed cyclin D3 than B-cell lymphomas. Furthermore, cyclin D3-overexpressing indolent lymphomas were associated with higher proliferation rate, higher p21Waf1 expression, lower p27Kip1 expression, and altered p53. Cyclin D3 overexpression identified a subgroup of patients with indolent B-cell lymphoma with adverse clinical features: patients were older, more frequently had "B" symptoms and extranodal involvement, and were more frequently in the high-intermediate or high-risk International Prognostic Index groups. At univariate analysis of indolent lymphomas, cyclin D3 overexpression was associated significantly with poor overall survival and poor relapse-free survival. The statistical significance was retained on multivariate analysis of overall survival and relapse-free survival. Our results suggest that cyclin D3 is expressed differentially among lymphoma subtypes and that overexpression might identify a subpopulation of patients with indolent lymphoma with adverse clinical features and poor outcome.
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PMID:Cyclin D3 expression in non-Hodgkin lymphoma. Correlation with other cell cycle regulators and clinical features. 1124 97

The tumor suppressor PTEN is one of the most commonly inactivated genes in human cancer. Glioblastoma multiforme cells harboring mutant PTEN have abnormally high levels of 3' phosphoinositides and elevated protein kinase B activity. Expression of wild-type PTEN in glioma cells, containing endogenous mutant PTEN, reduces 3' phosphoinositides levels, inhibits PKB activity, and induces G1 cell cycle arrest. We investigated the mechanism of the PTEN-induced growth arrest in glioma cell lines. Expression of PTEN is associated with increased expression of p27Kip1, decreased expression of cyclins A and D3, inhibition of cdk2 activity, and dephosphorylation of pRb. Inactivation of p53, by the human papilloma virus E6 oncoprotein, does not prevent PTEN-induced G1 arrest, implying that p53 is not required for G1 arrest. In contrast, p27Kip1 antisense oligonucleotides abrogated the growth arrest induced by PTEN. Furthermore, blocking p27Kip1 expression prevented the PTEN-induced reduction of cyclin-dependent kinase 2 activity, indicating that p27Kip1 functions upstream of cyclin-dependent kinase 2 in the PTEN regulatory cascade. These results implicate p27Kip1 as a critical mediator of PTEN-induced G1 arrest.
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PMID:p27Kip1 is required for PTEN-induced G1 growth arrest. 1128 Jul 73

Little information exists concerning the response of anaplastic thyroid carcinoma (ATC) cells to histone deacetylase inhibitors (HDAIs). In this study, the cellular response to the histone deacetylase inhibitors, sodium butyrate and trichostatin A, was analyzed in cell lines derived from primary anaplastic thyroid carcinomas. HDAIs repress the growth (proliferation) of ATC cell lines, independent of p53 status, through the induction of apoptosis and differential cell cycle arrest (arrested in G1 and G2/M). Apoptosis increases in response to drug treatment and is associated with the appearance of the cleaved form of the caspase substrate, poly-(ADP-ribose) polymerase (PARP). Cell cycle arrest is associated with the reduced expression of cyclins A and B, the increased expression of the cyclin-dependent kinase inhibitors, p21(Cip1/WAF1) and p27Kip1, the reduced phosphorylation of the retinoblastoma protein (pRb), and a reduction in cdk2 and cdk1-associated kinase activities. In ATC cells overexpressing cyclin E, drug treatment failed to replicate these events. These results suggest that growth inhibition of ATC cells by HDAIs is due to the promotion of apoptosis through the activation of the caspase cascade and the induction of cell cycle arrest via a reduction in cdk2- and cdk1-associated kinase activities.
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PMID:Histone deacetylase inhibitors promote apoptosis and differential cell cycle arrest in anaplastic thyroid cancer cells. 1134 29

Iron is essential for cellular proliferation in all organisms. When deprived of iron, the growth of cells is invariably inhibited. However, the mechanism involved remains largely unclear. In the present study, we have observed that subcytotoxic concentrations of desferroxamine mesylate (DFO), an iron chelator, specifically inhibited the transition from G1 to S-phase of Chang cells, a hepatocyte cell line. This was accompanied by the appearance of senescent biomarkers, such as enlarged and flattened cell morphology, senescence-associated beta-galactosidase activity and reduced expression of poly(ADP-ribose) polymerase. Concomitantly, p27Kip1 (where Kip is kinase-inhibitory protein) was induced markedly, whereas other negative cell-cycle regulators, such as p21Cip1 (where Cip is cyclin-dependent kinase-interacting protein), p15INK4B and p16INK4A (where INK is inhibitors of cyclin-dependent kinase 4), were not, implying its association in the G1 arrest. Furthermore, the induction of p27Kip1 was accompanied by an increased level of transforming growth factor beta1 (TGF-beta1) mRNA. When neutralized with an anti-(TGF-beta1) antibody, p27Kip1 induction was completely abolished, indicating that TGF-beta1 is the major inducer of p27Kip1. Finally, DFO-induced senescence-like arrest was found to be independent of p53, since cell-cycle arrest was still observed with two p53-negative cell lines, Huh7 and Hep3B cells. In conclusion, DFO induced senescence-like G1 arrest in hepatocyte cell lines and this was associated with the induction of p27Kip1 through TGF-beta1, but was independent of p53.
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PMID:Iron chelation-induced senescence-like growth arrest in hepatocyte cell lines: association of transforming growth factor beta1 (TGF-beta1)-mediated p27Kip1 expression. 1194 74

We comparatively assessed 41 mucinous colorectal carcinomas (MUCs) and 620 non-MUC (well-, moderately, and poorly differentiated adenocarcinoma) cases for clinicopathologic findings; and 41 MUCs and 115 randomly selected non-MUCs also were studied for the following: (1) apoptotic activity and Ki-67 immunoreactivity; (2) immunohistochemical expression of p21(WAF1/CIP1), p27Kip1, p53, and bcl-2; and (3) c-Ki-ras mutations. The rates for lymph node involvement and peritoneal dissemination were higher in MUCs than in non-MUCs. Multivariate analysis showed MUCs to have a worse prognosis than well-differentiated adenocarcinomas. The Ki-67 labeling for MUCs was significantly lower than that for non-MUCs, whereas the apoptotic index was significantly higher than for the well-differentiated type. The labeling for p21(WAF1/CIP1) and p27Kip1 was lower in MUCs (2.7% and 35.3%, respectively) than in well-differentiated adenocarcinomas (4.2% and 48.6%, respectively). MUCs can be considered a different tumor from the well-differentiated type, with a poor prognosis owing to frequent lymph node metastasis and peritoneal dissemination, and characterized by high apoptotic and low proliferative activities associated with low p21(WAF1/CIP1) and p27Kip1 expression.
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PMID:High apoptotic activity and low epithelial cell proliferation with underexpression of p21(WAF1/CIP1) and p27Kip1 of mucinous carcinomas of the colorectum: comparison with well-differentiated type. 1204 42

We previously described a genetically unstable human fibroblast cell strain (GM2995), isolated from normal appearing skin of a xeroderma pigmentosum group C patient that repeatedly underwent changes characteristic of the transformed phenotype upon serial cultivation in vitro. In order to gain information concerning genetic changes associated with the transformation of this xeroderma pigmentosum group C cell strain, we examined the expression/function of several cell cycle regulators during its serial cultivation. A mutation in exon 8 of the P53 gene was associated with loss of function of the p53 protein and appeared at about the same time that transformation occurred. Abnormal P53 function was confirmed by the lack of upregulation of p53 as well as activation of its downstream effectors p21Waf1 and HDM2 in high passage cells exposed to either gamma irradiation or ultraviolet C irradiation. Consistent with deregulation in cell cycle control, persistent hyper-phosphorylation of the retinoblastoma protein and lack of a decrease in p34cdc2 were observed in irradiated cells. Furthermore, retinoblastoma protein remained hyperphosphorylated in control high passage confluent cultures that were serum starved for 72 h. Compared with low passage cells, the expression levels of the cyclin-dependent kinase inhibitor p27Kip1 were significantly reduced and the pattern of expression of the von Hippel-Lindau protein was aberrant. These data indicate that the process of cellular transformation of this xeroderma pigmentosum group C cell strain involves the progressive acquisition of mutations and abnormalities in the expression/function of several cell cycle regulators.
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PMID:Cell cycle deregulation and xeroderma pigmentosum group C cell transformation. 1248 38

The cyclin-dependent kinase inhibitors p27Kip1 and p21WAF1/Cip1 play important roles in cell-cycle regulation. Although alterations of these genes have been linked to tumorigenesis of several human carcinomas, their involvement in head and neck squamous tumorigenesis is rarely investigated. To determine the role of these genes in the evolution of squamous carcinoma of the head and neck we evaluated their protein expression by immunohistochemistry in non-dysplastic squamous epithelium, premalignant lesions and oral squamous carcinomas. The p53 gene and Ki-67 expressions were correlated with traditional clinicopathologic variables. Our study shows that in histologically non-dysplastic squamous epithelium, p27 expression was noted mainly in superficial differentiated cells, whereas p21, p53 and Ki-67 staining was observed in basal and suprabasal cells. In dysplasia, divergent expression between p27 and p21 was observed: p27 precipitously decreased and p21, p53, and Ki-67 increased with histologic progression. In squamous carcinomas, p27 was mainly expressed in well differentiated tumor cell nests, while the expressions of p21, p53, and Ki-67 were variable in the poorly differentiated tumor areas. A significant inverse relationship between p27 expression and those of p21, p53, and Ki-67 was observed, but no significant association between any of these markers and clinicopathologic factors was noted in this cohort. Our study indicates that: i) down-regulation of p27 and up-regulation of p21 are associated with early progression of HNSC, ii) p21 expression correlates positively with proliferation while p27 correlates positively with cell differentiation and iii) concurrent p27 and p21 expression analysis may allow for better assessment of HNSC progression.
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PMID:Differential expressions of cyclin-dependent kinase inhibitors (p27 and p21) and their relation to p53 and Ki-67 in oral squamous tumorigenesis. 1252 41

Molecular markers predicting response to preoperative chemotherapy would be of major clinical relevance in breast cancer. Therefore, we studied the relationship between the expression of cell cycle regulatory proteins and clinical outcome in breast cancer patients receiving preoperative chemotherapy. Expression of p2lWaf1, p27KiP1, p53, cyclin D3 and Ki-67 was determined in breast carcinomas by means of immunohistochemistry both prior and after preoperative chemotherapy. Expression data were compared with both clinical parameters and response to preoperative chemotherapy with either cyclophosphamide/methotrexate/5-fluorouracil (CMF, n = 29) or epirubicin/docetaxel (ED, n = 36). In paired samples before and after preoperative chemotherapy, the percentage of p21Waf1, p27Kip1, p53 and cyclin D3 positive nuclei of tumor cells in postchemotherapy specimens was significantly higher than the percentage in prechemotherapy samples but no change in Ki-67 expression was observed. High Ki-67 expression (p = 0.02), negative estrogen receptor status (p = 0.01) and negative progesterone receptor status (p = 0.04) were associated with complete pathologic response to chemotherapy, whereas the other markers did not predict response. In conclusion, expression levels of p21Waf1, p27Kip1, p53 and cyclin D3 significantly increased after preoperative chemotherapy in breast carcinomas but only high Ki-67 expression, negative estrogen receptor status and negative progesterone receptor status were associated with complete pathologic response to preoperative chemotherapy.
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PMID:Expression of cell cycle regulatory proteins in breast carcinomas before and after preoperative chemotherapy. 1261 62

We investigated 31 cases of pleomorphic carcinomas of the lung, with a double component of neoplastic epithelial cells and of spindle and/or giant cells. To correlate the morphologic diversity of these two cell components with their immunophenotype, we evaluated the expression of several gene products involved in cell differentiation (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, vimentin, S-100 protein, smooth muscle actin, desmin), cell cycle control and apoptosis (p53, p21Waf1, p27Kip1, FHIT), tumor growth (proliferative fraction, assessed by Ki-67 antigen, and microvascular density, assessed by CD34 immunostaining), and tumor cell motility (fascin). We found the epithelial component to be significantly more immunoreactive for cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, cell cycle inhibitors p21Waf1, p27Kip1 and tumor suppressor gene FHIT, whereas the sarcomatoid component, independent of tumor stage and size, was more immunoreactive for vimentin, fascin, and microvascular density. Accordingly, we suggest a model of tumorigenesis whereby the mesenchymal phenotype of pleomorphic cells is likely induced by the selective activation and segregation of several molecules involved in cell differentiation, cell cycle control, and tumor cell growth and motility. Whether pleomorphic carcinomas of the lung are tumors with a dismal prognosis still remains an unsettled issue. In our series, however, stage I pleomorphic carcinomas have the same clinical behavior as ordinary non-small cell lung cancer, and only a high proliferative index (Ki-67 labeling index >35%) is associated with a worse prognosis in these tumors.
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PMID:Pleomorphic carcinomas of the lung show a selective distribution of gene products involved in cell differentiation, cell cycle control, tumor growth, and tumor cell motility: a clinicopathologic and immunohistochemical study of 31 cases. 1296 Aug 4


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