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)

Deregulation of cyclin, cyclin-dependent kinases (CDKs) and their inhibitors could have a pivotal role in the development of diverse human cancers. We examined the genetic status and the expression of CDK inhibitors (p21, p27, p16 and p15), CDK2 and cyclins (A, D1 and E) in eight gastric carcinoma cell lines, in comparison with the status of p53 gene alterations. All the cell lines (except MKN-28) that contained a p53 gene abnormality expressed very low or undetectable levels of p21 mRNA, while the cell lines (MKN-45 and -74) with wild-type p53 gene expressed high levels of p21 mRNA. An inverse correlation was found between the level of p21 mRNA and the expression of mRNAs for CDK2 and G1 cyclins. MKN-28 was an exception; it contained mutated p53, and expressed mRNAs for p21, CDK2 and G1 cyclins at high levels. Only MKN-45 and -74, with wild-type p53, expressed considerable levels of p21 protein. Homozygous deletion of the p16 and p15 genes was detected in two (MKN-45 and HSC-39) of the eight gastric carcinoma cell lines, p16 protein was not expressed in three cell lines (MKN-28, MKN-74 and KATO-III), as well as MKN-45 and HSC-39. Rearrangement of the p15 gene was found in TMK-1. Rearrangement of the p27 gene was detected in MKN-45, although the expression of p27 protein was well preserved in all the gastric carcinoma cell lines. The expression of pRb was also preserved in all the cell lines except KATO-III. No obvious correlation was observed between the p53 gene status and the expression of p27 and p16. These findings suggest that abnormal regulation of CDK2/cyclins and CDK inhibitors might be involved in deregulated growth of gastric carcinomas.
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PMID:Genetic status and expression of the cyclin-dependent kinase inhibitors in human gastric carcinoma cell lines. 879 88

In yeast functional assay (YF assay), a newly developed screening system for p53 mutation, wild-type p53 gives white yeast colonies and transcriptionally inactive mutant p53 gives red colonies. In the present study, the author applied YF assay to the detection of p53 mutations in human oral squamous cell carcinoma (SCC). Total RNA was extracted from samples and YF assay was performed. Four SCC cell lines (SAS, HSC-2, HSC-3 and Ca9-22) known to have p53 mutations all gave 100% red colonies, whereas nine oral non-tumor tissues gave 2.9-10% (average 5.2 +/- 2.7%) red colonies. Furthermore, a rat hepatoma cell line, WHp53, which had been transfected with human wild-type p53 expression vector, presented 7.8% red colonies. Thus the functional assays of tissues or cells containing only wild-type p53 give 3-10% red colonies as a background. To assess the detectability of p53 mutations, YF assay was performed on mixtures of wild-type and mutant p53 PCR products at serial ratios. The result showed that the mutation was detectable if 6% population of transcriptionally inactive mutant p53 mRNA were present in the total p53 mRNA. Twenty-two clinical samples of human oral SCC were then tested by YF assay. Fourteen out of 22 cases gave more than 20% red colonies. In these 14 cases, clonal p53 mutations with deletion, nonsense mutation or missense mutation were identified. In a case which gave 17% red colonies, identical p53 mutation was found in 2 out of 6 independent red colonies. However, no identical mutations were found in the cases giving 13, 9 and 8% red colonies. Based on these results, the author proposes that 20% of red colonies is the minimal value for the diagnosis of p53 mutation in YF assay under PCR conditions using Pfu polymerase and hot start method.
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PMID:[Detectability and diagnostic criteria of p53 gene mutations in human oral squamous cell carcinoma using yeast functional assay]. 914 13

Five lines (MKN-28, MKN-45, MKN-74, KATO-III, and HSC-39) of human gastric carcinoma cells were treated with 1 microgram/ml cisplatin for 12, 24, 36, 48, and 72 h. Apoptotic indices (percentages of apoptotic cells) were analyzed at each time point. After incubation with cisplatin, apoptotic cells were detected more frequently among MKN-45 and MKN-74 cells with a wild-type gene for p53 and without expression of the bcl-2 protein than among HSC-39, MKN-28, and KATO-III cells with a mutation or complete deletion of the gene for p53 and with overexpression of the bcl-2 protein. The levels of p53 protein increased after treatment with cisplatin in MKN-74 cells. However, levels of bcl-2 protein were reduced in KATO-III after treatment with cisplatin. Thus, p53 status and the expression of bcl-2 by tumor cells might be good indicators of sensitivity to chemotherapy for patients with gastric cancer.
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PMID:Changes in levels of expression of p53 and the product of the bcl-2 in lines of gastric cancer cells during cisplatin-induced apoptosis. 932 93

Retinoic acid (RA) has been shown to be effective in suppressing premalignant lesions and preventing second primary malignancies in patients cured of squamous cell carcinoma of the head and neck. However, the precise mechanisms of these effects are still uncertain. In the present study, we examined the effect of 9-cis-RA on the growth of six oral cancer cell lines (HSC-2, HSC-3, HSC-4, Ca9-22, Ho-1-N-1 and Ho-1-u-1). In addition, the relationship among growth and differentiation of tumor cells, RA responsiveness and the expression of nuclear retinoic acid receptors were also investigated. Among the six cell lines examined, five (HSC-2, HSC-3, HSC-4, Ca9-22 and Ho-1-u-1) displayed growth inhibition after treatment with 1x10(-6) M 9-cis-RA, while Ho-1-N-1 cells were resistant to 9-cis-RA. The expression level of RARbeta in 9-cis-RA resistant Ho-1-N-1 cells was very low in comparison with the sensitive cell lines. On the other hand, all of the six the cell lines expressed RARalpha, RARgamma, and RXRalpha at various levels. 9-cis-RA induced accumulation of cell population in G1 phase in HSC-3 cells on the 6th day of the treatment, followed by a marked reduction in the levels of hyperphosphorylated pRB, whereas p53 level was not altered. Interestingly, 9-cis-RA induced transiently the expression of p21(Waf1/Cip1), p27(Kip1), p300, CBP, BAX, Bak and bcl-2 proteins, respectively. This effect was associated with reduction of cyclin D1, cdk4 and CDK-activating kinase (cyclin H and cdk7) protein in HSC-3 cells. These results suggest that the growth inhibitory effect of 9-cis-RA on oral squamous cell carcinoma may depend on the expression levels of RARs, especially RARbeta proteins and RXRalpha proteins, and that 9-cis-RA may provide a powerful therapeutic agent for head and neck cancers.
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PMID:Effect of 9-cis-retinoic acid on oral squamous cell carcinoma cell lines. 1073 15

We have investigated the CDDP sensitivities of two tongue cancer cell lines with differing p53 genetic status, one with wild-type p53 (SAS) and the other with mutant-type p53 (HSC-4). SAS was about 2 times more sensitive at the D10 dose and demonstrated increased p53 and Bax protein levels at 10 h after CDDP treatment on Western blot analysis. On the other hand, overexpression of p53 in HSC-4 was observed without CDDP treatment and no elevation of Bax could be detected. Apoptosis was observed after CDDP treatment in SAS but not in HSC-4 by Hoechst 33342-staining and electrophoresis methods. These findings indicate that p53 plays an important role in apoptosis as a positive regulator of Bax expression. It is suggested that p53 status may have predictive potential with regard to response to CDDP therapy.
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PMID:CDDP induces p53-dependent apoptosis in tongue cancer cells. 1093 92

Molecular characterization of eight gastric cancer cell lines established in Japan are summarized according to the genetic and epigenetic alterations and growth factor status. TMK-1 poorly differentiated adenocarcinoma cell line harbors mutant p53 tumor suppressor gene and rearrangement of p15MTS2. MKN-1 adenosquamous carcinoma line with mutant p53 reveals silencing of E-cadherin by promoter CpG hypermethylation. MKN-7 well-differentiated adenocarcinoma cell line has amplification of c-erbB2 oncogene and cyclin E gene. MKN-28 well-differentiated adenocarcinoma cell line reveals mutations in p53 and APC tumor suppressor genes and silencing of CD44. The MKN-45 poorly differentiated adenocarcinoma cell line with wild-type p53 is characterized by homozygous deletion of p16CDKN2/MTS1/INK4A and p15MTS2, amplification of c-met oncogene and promoter mutation of E-cadherin. MKN-74 derived from moderately differentiated tubular adenocarcinoma has wild-type p53. KATO-III signet ring cell carcinoma line has genomic deletion of p53, amplification of K-sam and c-met oncogene and mutation of E-cadherin. HSC-39 signet ring cell carcinoma cell line harboring p53 missense mutation has homozygous deletion of p16CDKN2/MTS1/INK4A and p15MTS2, amplifications of c-myc, c-met, K-sam and CD44 gene and mutation in beta-catenin gene.
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PMID:Molecular characteristics of eight gastric cancer cell lines established in Japan. 1110 48

The extent of lymph node metastasis is a major determinant in the prognosis of oral squamous cell carcinoma (OSCC). We present here a new OSCC cell line, MSCC-1, established from a lymph node metastasis of a patient with OSCC of gingiva. First, we examined the expression of p27, p53 and Ki-67 in non-neoplastic mucosa, primary and metastatic cancer lesions by immunohistochemistry. Metastatic cancer cells in the lymph node showed the reduced expression of p27 in comparison with cancer cells in the primary lesion. Cancer celLs both in the primary and metastatic lesions showed overexpression of p53 and Ki-67. Overexpression of p53 and reduced expression of p27 in MSCC-1 cells were also determined by western blot analysis. To characterize MSCC-1 cells, furthermore, we examined the invasive activity and cell proliferation of MSCC-1, comparing with those of other OSCC cell lines, HSC-2 and HSC-3 cells. The invasive capacity of MSCC-1 cells was significant higher than HSC-2 and HSC-3 cells, but cell growth of MSCC-1 cells was slower than HSC-2 and HSC-3 cells. Moreover, we examined the p27 degradation activity by in vitro degradation assay. Interestingly, MSCC-1 cells have the strongest p27 degradation activity among the OSCC cell lines examined. In the present study, we newly established MSCC-1 cells with strong invasiveness and p27 degradation activity from a metastatic lesion. These findings suggest that high activity of p27 degradation may concern with invasiveness of OSCC cells and that MSCC-1 cells can be a useful cell model for studying the detailed mechanism of p27 degradation, invasion and metastasis of OSCC.
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PMID:Establishment of an oral squamous cell carcinoma cell line with high invasive and p27 degradation activities from a lymph node metastasis. 1274 77

Two controversial issues regarding p53 are whether it is involved in apoptosis induction of tumor cells by a histone deacetylase (HDAC) inhibitor and, given that p53 is indeed involved, which genes of acetylated p53 targets are responsible for giving rise to apoptotic death. We, in the present study, first confirmed that some substantial extent of apoptotic cell death was seen when p53-deficient cells (KATO-III) were transfected with wild-type p53 and treated with sodium butyrate (SB) or trichostatin A. By Western blotting, using specific antibodies, we then demonstrated that residues 320, 373, and 382 lysines of p53 were acetylated in KATO-III cells transfected with wild-type p53 (KATO-III/p53) treated with a HDAC inhibitor. However, as revealed by terminal deoxynucleotidyl transferase-mediated nick end labeling staining, only those KATO-III cells transfected with K320R p53 or K373R p53 became insensitive to the HDAC inhibitor, suggesting that these two residues of p53 may be essential for HDAC inhibitor-induced apoptosis, whereas others such as K382R p53 may not. Furthermore, reverse transcription-PCR demonstrated that among various p53-related proapoptotic genes, expression of PIG3 and NOXA were clearly enhanced by SB treatment in KATO-III/p53 cells but not in KATO-III/K320R or KATO-III/K373R cells. Finally, we revealed that apoptosis could be evoked by SB even in cells where p53 mutations occur at residues other than 320 lysine or 373 lysine (TMK-1 and HSC-39 cells) and that this apoptosis was significantly, although not totally, suppressed by the anti-p53 antisense. It was, therefore, concluded that acetylation of the p53 molecule at residues 320 and 373, giving rise to up-regulation of PIG3 and NOXA, is one of the mechanisms for induction of apoptosis by HDAC inhibitors in cancer cells.
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PMID:Induction of PIG3 and NOXA through acetylation of p53 at 320 and 373 lysine residues as a mechanism for apoptotic cell death by histone deacetylase inhibitors. 1469 12

Resistance to anoikis, or apoptosis triggered by detachment from the extracellular matrix (ECM), lengthens the survival of malignant cells, facilitating reattachment and colonization of secondary sites. To examine the molecular mechanisms underlying resistance to anoikis in human oral squamous cell carcinoma (SCC) cells, we cultured human squamous carcinoma (HSC-3) cells in suspension on plates coated with poly-2-hydroxyethyl methacrylate, which blocks access to the ECM. Cells in suspension that formed multicellular aggregates had significantly lower levels of apoptosis than single cells. Aggregates, but not single cells, had high levels of fibronectin. Preincubation with a cyclic arginine-glycine-aspartic acid peptide or fibronectin-blocking antibody significantly increased anoikis. Single cells had markedly lower expression of the integrin alpha(v) receptor than aggregates. Blocking alpha(v) function with a blocking antibody or by transfection with an antisense oligonucleotide increased apoptosis and inhibited aggregation. In single cells but not aggregates, phosphorylation of the integrin-associated focal adhesion kinase (FAK) at tyrosine 397 was reduced, and p53 levels were increased. Apoptosis was increased by blocking FAK with an antisense oligonucleotide and reduced by blocking p53. These findings show that SCC cells escape suspension-induced anoikis by forming multicellular aggregates that avail themselves of fibronectin survival signals mediated by integrin alpha(v). Single cells in suspension that do not form aggregates undergo anoikis because of decreased FAK phosphorylation and increased p53 levels. Thus, SCC cells appear to use neighboring cells and the ECM molecule FN to promote the metastatic phenotype.
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PMID:Squamous cell carcinoma cell aggregates escape suspension-induced, p53-mediated anoikis: fibronectin and integrin alphav mediate survival signals through focal adhesion kinase. 1533 8

The p53R2 gene encodes the ribonucleotide reductase (RR) small subunit 2 homologue, and is induced by several stress signals activating p53, such as DNA-damaging agents. The p53R2 gene product causes an increase in the deoxynucleotide triphosphate (dNTP) pool in the nucleus, which facilitates DNA repair and synthesis. We hypothesized that p53R2 would be a good molecular target for cancer gene therapy. In this study, three human oral cancer cell lines (SAS, HSC-4 and Ca9-22), a human breast cancer cell line MCF-7, and a normal human fibroblast cell line NHDF were tested. We silenced the expression of p53R2 with the highly specific post-transcriptional suppression of RNA interference (RNAi). We investigated p53R2 expression with the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The sensitivity to anticancer agents was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of p53R2 showed no association with the mutational status of p53. The cancer cell lines with higher p53R2 expression were more resistant to 5-FU. RNAi-mediated p53R2 reduction selectivity inhibited growth and enhanced chemosensitivity in cancer cell lines but not in normal fibroblasts. These results suggest that basal transcription of p53R2 could be associated with the sensitivity to anticancer agents. Moreover, we assessed the possibility that p53R2 would be a good molecular target, and report that RNAi targeting of p53R2 could be useful for oral cancer gene therapy.
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PMID:Silencing of the p53R2 gene by RNA interference inhibits growth and enhances 5-fluorouracil sensitivity of oral cancer cells. 1589 Feb 38


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