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Sample records for activity p53 expression

  1. p53 increases caspase-6 expression and activation in muscle tissue expressing mutant huntingtin

    Ehrnhoefer, Dagmar E; Skotte, Niels H; Ladha, Safia;

    2014-01-01

    as in muscle tissues from two different HD mouse models. p53, a transcriptional activator of caspase-6, is upregulated in neuronal cells and tissues expressing mutant huntingtin. Activation of p53 leads to a dramatic increase in levels of caspase-6 mRNA, caspase-6 activity and cleavage of lamin A....... Using mouse embryonic fibroblasts (MEFs) from YAC128 mice, we show that this increase in caspase-6 activity can be mitigated by pifithrin-α (pifα), an inhibitor of p53 transcriptional activity, but not through the inhibition of p53's mitochondrial pro-apoptotic function. Remarkably, the p53-mediated...... increase in caspase-6 expression and activation is exacerbated in cells and tissues of both neuronal and peripheral origin expressing mutant huntingtin (Htt). These findings suggest that the presence of the mutant Htt protein enhances p53 activity and lowers the apoptotic threshold, which activates caspase...

  2. Regulation of Plasminogen Activator Inhibitor-1 Expression by Tumor Suppressor Protein p53*

    Shetty, Sreerama; Shetty, Praveenkumar; Idell, Steven; Velusamy, Thirunavukkarasu; Bhandary, Yashodhar P.; Shetty, Rashmi S.

    2008-01-01

    H1299 lung carcinoma cells lacking p53 (p53-/-) express minimal amounts of plasminogen activator inhibitor-1 (PAI-1) protein as well as mRNA. p53-/- cells express highly unstable PAI-1 mRNA. Transfection of p53 in p53-/- cells enhanced PAI-1 expression and stabilized PAI-1 mRNA. On the contrary, inhibition of p53 expression by RNA silencing in non-malignant human lung epithelial (Beas2B) cells decreased basal as well as urokinase-type plasminogen activator-induced PAI-...

  3. Genome-scale functional analysis of the human genes modulating p53 activity by regulating MDM2 expression in a p53-independent manner.

    Kim, Dong Min; Choi, Seung-Hyun; Yeom, Young Il; Min, Sang-Hyun; Kim, Il-Chul

    2016-09-16

    MDM2, a critical negative regulator of p53, is often overexpressed in leukemia, but few p53 mutations are found, suggesting that p53-independent MDM2 expression occurs due to alterations in MDM2 upstream regulators. In this study, a high MDM2 transcription level was observed (41.17%) regardless of p53 expression in patient with acute myeloid leukemia (AML). Therefore, we performed genome-scale functional screening of the human genes modulating MDM2 expression in a p53-independent manner. We searched co-expression profiles of genes showing a positive or negative pattern with MDM2 expression in a DNA microarray database, selected1089 links, and composed a screening library of 368 genes. Using MDM2 P1 and P2 promoter-reporter systems, we screened clones regulating MDM2 transcriptions in a p53-independent manner by overexpression. Nine clones from the screening library showed enhanced MDM2 promoter activity and MDM2 expression in p53-deficient HCT116 cells. Among them, six clones, including NTRK2, GNA15, SFRS2, EIF5A, ELAVL1, and YWHAB mediated MAPK signaling for expressing MDM2. These results indicate that p53-independent upregulation of MDM2 by increasing selected clones may lead to oncogenesis in AML and that MDM2-modulating genes are novel potential targets for AML treatment. PMID:27524244

  4. Biological activity and safety of adenoviral vector-expressed wild-type p53 after intratumoral injection in melanoma and breast cancer patients with p53-overexpressing tumors

    Dummer, R; Bergh, J; Karlsson, Y; Horovitz, JA; Mulder, NH; Huinin, DT; Burg, G; Hofbauer, G; Osanto, S

    2000-01-01

    p53 mutations are common genetic alterations in human cancer. Gene transfer of a wild-type (wt) p53 gene reverses the loss of normal p53 function in vitro and in vivo. A phase I dose escalation study of single intratumoral (i.t.) injection of a replication-defective adenoviral expression vector cont

  5. Regulation of Mutant p53 Protein Expression

    Vijayakumaran, Reshma; Tan, Kah Hin; Miranda, Panimaya Jeffreena; Haupt, Sue; Haupt, Ygal

    2015-01-01

    For several decades, p53 has been detected in cancer biopsies by virtue of its high protein expression level which is considered indicative of mutation. Surprisingly, however, mouse genetic studies revealed that mutant p53 is inherently labile, similar to its wild type (wt) counterpart. Consistently, in response to stress conditions, both wt and mutant p53 accumulate in cells. While wt p53 returns to basal level following recovery from stress, mutant p53 remains stable. In part, this can be e...

  6. Expression of Androgen Receptor Is Negatively Regulated By p53

    Fatouma Alimirah

    2007-12-01

    Full Text Available Increased expression of androgen receptor (AR in prostate cancer (PC is associated with transition to androgen independence. Because the progression of PC to advanced stages is often associated with the loss of p53 function, we tested whether the p53 could regulate the expression of AR gene. Here we report that p53 negatively regulates the expression of AR in prostate epithelial cells (PrECs. We found that in LNCaP human prostate cancer cells that express the wild-type p53 and AR and in human normal PrECs, the activation of p53 by genotoxic stress or by inhibition of p53 nuclear export downregulated the expression of AR. Furthermore, forced expression of p53 in LNCaP cells decreased the expression of AR. Conversely, knockdown of p53 expression in LNCaP cells increased the AR expression. Consistent with the negative regulation of AR expression by p53, the p53-null HCT116 cells expressed higher levels of AR compared with the isogenic HCT116 cells that express the wildtype p53. Moreover, we noted that in etoposide treated LNCaP cells p53 bound to the promoter region of the AR gene, which contains a potential p53 DNA-binding consensus sequence, in chromatin immunoprecipitation assays. Together, our observations provide support for the idea that the loss of p53 function in prostate cancer cells contributes to increased expression of AR.

  7. Influenza A Viruses Control Expression of Proviral Human p53 Isoforms p53β and Δ133p53α

    Terrier, Olivier; Marcel, Virginie; Cartet, Gaëlle; Lane, David P; Lina, Bruno; Rosa-Calatrava, Manuel; Bourdon, Jean-Christophe

    2012-01-01

    Previous studies have described the role of p53 isoforms, including p53β and Δ133p53α, in the modulation of the activity of full-length p53, which regulates cell fate. In the context of influenza virus infection, an interplay between influenza viruses and p53 has been described, with p53 being involved in the antiviral response. However, the role of physiological p53 isoforms has never been explored in this context. Here, we demonstrate that p53 isoforms play a role in influenza A virus infec...

  8. Acetylation Is Indispensable for p53 Activation

    Tang, Yi; Zhao, Wenhui; Chen, Yue; Zhao, Yingming; Gu, Wei

    2008-01-01

    The activation of the tumor suppressor p53 facilitates the cellular response to genotoxic stress; however, the p53 response can only be executed if its interaction with its inhibitor Mdm2 is abolished. There have been conflicting reports on the question of whether p53 posttranslational modifications, such as phosphorylation or acetylation, are essential or only play a subtle, fine-tuning role in the p53 response. Thus, it remains unclear whether p53 modification is absolutely required for its...

  9. p53 isoform Δ113p53 is a p53 target gene that antagonizes p53 apoptotic activity via BclxL activation in zebrafish

    Chen, Jun; Ng, Sok Meng; Chang, Changqing; Zhang, Zhenhai; Bourdon, Jean-Christophe; Lane, David P; Peng, Jinrong

    2009-01-01

    p53 is a well-known tumor suppressor and is also involved in processes of organismal aging and developmental control. A recent exciting development in the p53 field is the discovery of various p53 isoforms. One p53 isoform is human Δ133p53 and its zebrafish counterpart Δ113p53. These N-terminal-truncated p53 isoforms are initiated from an alternative p53 promoter, but their expression regulation and physiological significance at the organismal level are not well understood. We show here that ...

  10. Activation of tumor suppressor p53 gene expression by magnetic thymine-imprinted chitosan nanoparticles.

    Lee, Mei-Hwa; Thomas, James L; Chen, Jian-Zhou; Jan, Jeng-Shiung; Lin, Hung-Yin

    2016-02-01

    Chitosan is a natural biodegradable polysaccharide that has been used to enhance gene delivery, owing to the ease with which chitosan nanoparticles enter the nucleus of cells. To study the effects of nuclear delivery of telomeric gene sequences, which contain thymine, we formed magnetic thymine-imprinted chitosan nanoparticles (TIPs) by the precipitation of chitosan, mixed with thymine and magnetic nanoparticles (to aid in separations). The mean size of the TIPS was 116 ± 18 nm; the dissociation constant for thymine was 21.8 mg mL(-1). We then treated human hepatocellular carcinoma (HepG2) with TIPs nanoparticles bearing bound thymine or a bound telomeric DNA sequence. The expression of the tumor suppressor p53 gene increased when TIPs were applied and decreased when telomere-bound TIPs were applied. PMID:26693943

  11. Study of the expressions of p53 and bcl-2 genes, the telomerase activity and apoptosis in GIST patients

    Qiang Wang; You-Wei Kou

    2007-01-01

    AIM: To explore the relationship between clinicobiological behavior and the expression levels of telomerase activity,apoptosis, p53 gene and bcl-2 gene in gastrointestinal stromal tumors (GISTs).METHODS: The intensity of telomerase activity,apoptosis, p53 and bcl-2 expression in GISTs were detected by telomeric repeat amplification protocol, in situ end-labeling technique, and immunohistochemistry,respectively.RESULTS: The positive rates of telomerase activity of malignant GIST, potential malignant GIST and benign GIST were 85% (17/20), 22.8% (2/9) and 0 (0/9),respectively. The apoptosis indices of malignant GIST,potential malignant GIST, and benign GIST were 11.7 ± 5.4, 30.2 ± 5.6 and 45.2 ± 7.2, respectively. The intensity of telomerase activity and apoptosis were related to the biological characteristics of GISTs (85% vs 22.8%, 0, 0; P < 0.01 or 11.7±5.4 vs 30.2 ± 5.6, 45.2 ± 7.2, 72.1 ± 9.3; P < 0.05). The intensity of telomerase activity was negatively correlated with cellular apoptosis (22.9 ± 8.4 vs 9.5 ± 5.7, P < 0.01). The intensity of telomerase activity was positively correlated with p53,bcl-2 expression (40.0% vs 78.9%, 40.0% vs 84.2%;P < 0.05).CONCLUSION: The detection of telomerase activity,apoptosis and its control genes in GIST will be helpful for the discrimination of the malignant and benign GIST and evaluation of the prognosis.

  12. Abrogation of Gli3 expression suppresses the growth of colon cancer cells via activation of p53

    Kang, Han Na [Graduate School of Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Oh, Sang Cheul; Kim, Jun Suk [Division of Oncology/Hematology, Department of Internal Medicine, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of); Yoo, Young A., E-mail: ydanbi@korea.ac.kr [Brain Korea 21 Program for Biomedical Science, Korea University College of Medicine, Korea University, Seoul 136-705 (Korea, Republic of)

    2012-03-10

    p53, the major human tumor suppressor, appears to be related to sonic hedgehog (Shh)-Gli-mediated tumorigenesis. However, the role of p53 in tumor progression by the Shh-Gli signaling pathway is poorly understood. Herein we investigated the critical regulation of Gli3-p53 in tumorigenesis of colon cancer cells and the molecular mechanisms underlying these effects. RT-PCR analysis indicated that the mRNA level of Shh and Gli3 in colon tumor tissues was significantly higher than corresponding normal tissues (P < 0.001). The inhibition of Gli3 by treatment with Gli3 siRNA resulted in a clear decrease in cell proliferation and enhanced the level of expression of p53 proteins compared to treatment with control siRNA. The half-life of p53 was dramatically increased by treatment with Gli3 siRNA. In addition, treatment with MG132 blocked MDM2-mediated p53 ubiquitination and degradation, and led to accumulation of p53 in Gli3 siRNA-overexpressing cells. Importantly, ectopic expression of p53 siRNA reduced the ability of Gli3 siRNA to suppress proliferation of those cells compared with the cells treated with Gli3 siRNA alone. Moreover, Gli3 siRNA sensitized colon cancer cells to treatment with anti-cancer agents (5-FU and bevacizumab). Taken together, our studies demonstrate that loss of Gli3 signaling leads to disruption of the MDM2-p53 interaction and strongly potentiate p53-dependent cell growth inhibition in colon cancer cells, indicating a basis for the rational use of Gli3 antagonists as a novel treatment option for colon cancer.

  13. Abrogation of Gli3 expression suppresses the growth of colon cancer cells via activation of p53

    p53, the major human tumor suppressor, appears to be related to sonic hedgehog (Shh)–Gli-mediated tumorigenesis. However, the role of p53 in tumor progression by the Shh–Gli signaling pathway is poorly understood. Herein we investigated the critical regulation of Gli3–p53 in tumorigenesis of colon cancer cells and the molecular mechanisms underlying these effects. RT-PCR analysis indicated that the mRNA level of Shh and Gli3 in colon tumor tissues was significantly higher than corresponding normal tissues (P < 0.001). The inhibition of Gli3 by treatment with Gli3 siRNA resulted in a clear decrease in cell proliferation and enhanced the level of expression of p53 proteins compared to treatment with control siRNA. The half-life of p53 was dramatically increased by treatment with Gli3 siRNA. In addition, treatment with MG132 blocked MDM2-mediated p53 ubiquitination and degradation, and led to accumulation of p53 in Gli3 siRNA-overexpressing cells. Importantly, ectopic expression of p53 siRNA reduced the ability of Gli3 siRNA to suppress proliferation of those cells compared with the cells treated with Gli3 siRNA alone. Moreover, Gli3 siRNA sensitized colon cancer cells to treatment with anti-cancer agents (5-FU and bevacizumab). Taken together, our studies demonstrate that loss of Gli3 signaling leads to disruption of the MDM2–p53 interaction and strongly potentiate p53-dependent cell growth inhibition in colon cancer cells, indicating a basis for the rational use of Gli3 antagonists as a novel treatment option for colon cancer.

  14. Quercetin enhances the antitumor activity of trichostatin A through upregulation of p53 protein expression in vitro and in vivo.

    Shu-Ting Chan

    Full Text Available This study investigated the effects of quercetin on the anti-tumor effect of trichostatin A (TSA, a novel anticancer drug, in vitro and in vivo and the possible mechanisms of these effects in human lung cancer cells. We first showed that quercetin (5 µM significantly increased the growth arrest and apoptosis in A549 cells (expressing wild-type p53 induced by 25 ng/mL of (82.5 nM TSA at 48 h by about 25% and 101%, respectively. However, such enhancing effects of quercetin (5 µM were not significant in TSA-exposed H1299 cells (a p53 null mutant or were much lower than in A549 cells. In addition, quercetin significantly increased TSA-induced p53 expression in A549 cells. Transfection of p53 siRNA into A549 cells significantly but not completely diminished the enhancing effects of quercetin on TSA-induced apoptosis. Furthermore, we demonstrated that quercetin enhanced TSA-induced apoptosis through the mitochondrial pathway. Transfection of p53 siRNA abolished such enhancing effects of quercetin. However, quercetin increased the acetylation of histones H3 and H4 induced by TSA in A549 cells, even with p53 siRNA transfection as well as in H1299 cells. In a xenograft mouse model of lung cancer, quercetin enhanced the antitumor effect of TSA. Tumors from mice treated with TSA in combination with quercetin had higher p53 and apoptosis levels than did those from control and TSA-treated mice. These data indicate that regulation of the expression of p53 by quercetin plays an important role in enhancing TSA-induced apoptosis in A549 cells. However, p53-independent mechanisms may also contribute to the enhancing effect of quercetin.

  15. Quercetin enhances the antitumor activity of trichostatin A through upregulation of p53 protein expression in vitro and in vivo.

    Chan, Shu-Ting; Yang, Nae-Cherng; Huang, Chin-Shiu; Liao, Jiunn-Wang; Yeh, Shu-Lan

    2013-01-01

    This study investigated the effects of quercetin on the anti-tumor effect of trichostatin A (TSA), a novel anticancer drug, in vitro and in vivo and the possible mechanisms of these effects in human lung cancer cells. We first showed that quercetin (5 µM) significantly increased the growth arrest and apoptosis in A549 cells (expressing wild-type p53) induced by 25 ng/mL of (82.5 nM) TSA at 48 h by about 25% and 101%, respectively. However, such enhancing effects of quercetin (5 µM) were not significant in TSA-exposed H1299 cells (a p53 null mutant) or were much lower than in A549 cells. In addition, quercetin significantly increased TSA-induced p53 expression in A549 cells. Transfection of p53 siRNA into A549 cells significantly but not completely diminished the enhancing effects of quercetin on TSA-induced apoptosis. Furthermore, we demonstrated that quercetin enhanced TSA-induced apoptosis through the mitochondrial pathway. Transfection of p53 siRNA abolished such enhancing effects of quercetin. However, quercetin increased the acetylation of histones H3 and H4 induced by TSA in A549 cells, even with p53 siRNA transfection as well as in H1299 cells. In a xenograft mouse model of lung cancer, quercetin enhanced the antitumor effect of TSA. Tumors from mice treated with TSA in combination with quercetin had higher p53 and apoptosis levels than did those from control and TSA-treated mice. These data indicate that regulation of the expression of p53 by quercetin plays an important role in enhancing TSA-induced apoptosis in A549 cells. However, p53-independent mechanisms may also contribute to the enhancing effect of quercetin. PMID:23342112

  16. P53 family members modulate the expression of PRODH, but not PRODH2, via intronic p53 response elements.

    Ivan Raimondi

    Full Text Available The tumor suppressor p53 was previously shown to markedly up-regulate the expression of the PRODH gene, encoding the proline dehydrogenase (PRODH enzyme, which catalyzes the first step in proline degradation. Also PRODH2, which degrades 4-hydroxy-L-proline, a product of protein (e.g. collagen catabolism, was recently described as a p53 target. Here, we confirmed p53-dependent induction of endogenous PRODH in response to genotoxic damage in cell lines of different histological origin. We established that over-expression of TAp73β or TAp63β is sufficient to induce PRODH expression in p53-null cells and that PRODH expression parallels the modulation of endogenous p73 by genotoxic drugs in several cell lines. The p53, p63, and p73-dependent transcriptional activation was linked to specific intronic response elements (REs, among those predicted by bioinformatics tools and experimentally validated by a yeast-based transactivation assay. p53 occupancy measurements were validated in HCT116 and MCF7 human cell lines. Conversely, PRODH2 was not responsive to p63 nor p73 and, at best, could be considered a weak p53 target. In fact, minimal levels of PRODH2 transcript induction by genotoxic stress was observed exclusively in one of four p53 wild-type cell lines tested. Consistently, all predicted p53 REs in PRODH2 were poor matches to the p53 RE consensus and showed very weak responsiveness, only to p53, in the functional assay. Taken together, our results highlight that PRODH, but not PRODH2, expression is under the control of p53 family members, specifically p53 and p73. This supports a deeper link between proteins of the p53-family and metabolic pathways, as PRODH modulates the balance of proline and glutamate levels and those of their derivative alpha-keto-glutarate (α-KG under normal and pathological (tumor conditions.

  17. MEKK1/JNK signaling stabilizes and activates p53

    Fuchs, Serge Y.; Adler, Victor; Pincus, Matthew R.; Ronai, Ze’ev

    1998-01-01

    Activation of the tumor suppressor p53 by stress and damage stimuli often correlates with induction of stress kinases, Jun-NH2 kinase (JNK). As JNK association with p53 plays an important role in p53 stability, in the present study we have elucidated the relationship between the JNK-signaling pathway and p53 stability and activity. Expression of a constitutively active form of JNKK upstream kinase, mitogen-activated protein kinase kinase kinase (ΔMEKK1), increased the level of the exogenously...

  18. Mitochondrial dysfunction impairs tumor suppressor p53 expression/function.

    Compton, Shannon; Kim, Chul; Griner, Nicholas B; Potluri, Prasanth; Scheffler, Immo E; Sen, Sabyasachi; Jerry, D Joseph; Schneider, Sallie; Yadava, Nagendra

    2011-06-10

    Recently, mitochondria have been suggested to act in tumor suppression. However, the underlying mechanisms by which mitochondria suppress tumorigenesis are far from being clear. In this study, we have investigated the link between mitochondrial dysfunction and the tumor suppressor protein p53 using a set of respiration-deficient (Res(-)) mammalian cell mutants with impaired assembly of the oxidative phosphorylation machinery. Our data suggest that normal mitochondrial function is required for γ-irradiation (γIR)-induced cell death, which is mainly a p53-dependent process. The Res(-) cells are protected against γIR-induced cell death due to impaired p53 expression/function. We find that the loss of complex I biogenesis in the absence of the MWFE subunit reduces the steady-state level of the p53 protein, although there is no effect on the p53 protein level in the absence of the ESSS subunit that is also essential for complex I assembly. The p53 protein level was also reduced to undetectable levels in Res(-) cells with severely impaired mitochondrial protein synthesis. This suggests that p53 protein expression is differentially regulated depending upon the type of electron transport chain/respiratory chain deficiency. Moreover, irrespective of the differences in the p53 protein expression profile, γIR-induced p53 activity is compromised in all Res(-) cells. Using two different conditional systems for complex I assembly, we also show that the effect of mitochondrial dysfunction on p53 expression/function is a reversible phenomenon. We believe that these findings will have major implications in the understanding of cancer development and therapy. PMID:21502317

  19. p53 mutant breast cancer patients expressing p53γ have as good a prognosis as wild-type p53 breast cancer patients

    Bourdon, Jean-Christophe; Khoury, Marie,; Diot, Alexandra; Baker, Lee; Fernandes, Kenneth; Aoubala, Mustapha; Quinlan, Philip; Purdie, Colin; Jordan, Lee; Prats, Anne-Catherine; Lane, David; Thompson, Alastair

    2011-01-01

    International audience INTRODUCTION: Normal function of the p53 network is lost in most cancers, often through p53 mutation. The clinical impact of p53 mutations in breast cancer remains uncertain, especially where p53 isoforms may modify the effects of these p53 mutations. METHODS: Expression of p53β and p53γ isoforms, the isoforms identified in normal breast tissue, was detected by reverse transcription polymerase chain reaction from a cohort of 127 primary breast tumours. Expression of ...

  20. Resuscitation of wild-type p53 expression by disrupting ceramide glycosylation: a novel approach to target mutant p53 tumors

    Liu, Yong-Yu

    2011-01-01

    Mutant p53 is frequently detected in cancers lose of its ability in tumor suppression and gain of function in promoting tumor progression. Restoration of p53 functions by replacement of wild-type p53 and inhibition of its degradation or increment of its transcriptional activity has been applied in prevention and treatment of cancers. Recent evidence indicates that disrupting ceramide glycosylation can resuscitate wild-type p53 expression and p53-dependent apoptosis in mutant p53 tumors. Actin...

  1. Correlation of p53 gene mutation and expression of P53 protein in cholangiocarcinoma

    Xiao-Fang Liu; Hao Zhang; Shi-Guang Zhu; Xian-Ting Zhou; Hai-Long Su; Zheng Xu; Shao-Jun Li

    2006-01-01

    AIM: To characterize the tumor suppressor gene p53 mutations and study the correlation of p53 gene mutation and the expression of P53 protein in cholangiocarcinoma.METHODS: A total of 36 unselected, frozen samples of cholangiocarcinoma were collected. p53 gene status(exon 5-8) and P53 protein were examined by automated sequencing and immunohistochemical staining, combined with the clinical parameters of patients.RESULTS: p53 gene mutations were found in 22 of 36 (61.1%) patients. Nineteen of 36 (52.8%) patients were positive for P53 protein expression. There were significant differences in extent of differentiation and invasion between the positive and negative expression of P53 protein. However, there were no significant differences in pathologic parameters between the mutations and non-mutations.CONCLUSION: The alterations of the p53 gene evaluated by DNA sequence analysis is relatively accurate. Expression of P53 protein could not act as an independent index to estimate the prognosis of cholangiocarcinoma.

  2. Expression of p53 in endometrial polyps with special reference to the p53 signature.

    Sho, Tomoko; Hachisuga, Toru; Kawagoe, Toshinori; Urabe, Rie; Kurita, Tomoko; Kagami, Seiji; Shimajiri, Shohei; Fujino, Yoshihisa

    2016-07-01

    We herein examined the significance of the p53 expression in endometrial polyps (EMPs). A total of 133 EMPs, including 62 premenopausal and 71 postmenopausal women with EMP, were immunohistochemically studied for the expression of estrogen receptor (ER)-alpha, Ki-67 and p53. Apoptotic cells were identified using a TUNEL assay. A DNA sequence analysis of TP53 exons 5 to 9 was performed. Among the premenopausal EMPs, a multivariate analysis showed the labeling index (LI) for Ki-67 to correlate significantly with that for p53 (PEMPs, the LI for Ki-67 correlated significantly with that for apoptosis (PEMPs (mean age: 70.2 years). The median Ki-67 index for the p53S was 7%, with no significant difference from that of the glands of the postmenopausal EMPs without the p53S (P=0.058). The median apoptotic index for the p53S was 0%, which was significantly lower than that of the postmenopausal EMPs without the p53S (P=0.002). Two of four p53Ss showed TP53 mutations according to the DNA sequence analysis. The presence of the p53S is not rare in postmenopausal EMPs with an advanced age. Among postmenopausal EMPs, the LI of Ki-67 significantly correlates with that of apoptosis. However, such a positive correlation between the LI of Ki-67 and apoptosis is not observed in p53S. PMID:26727623

  3. Ets-2 and p53 mediate cAMP-induced MMP-2 expression, activity and trophoblast invasion

    Goldman Shlomit

    2009-11-01

    Full Text Available Abstract Background We have previously shown that Matrix metalloproteinase (MMP -2 is a key-enzyme in early trophoblast invasion and that Protein Kinase A (PKA increases MMP-2 expression and trophoblast invasion. The aim of this study was to examine MMP -2 regulation by PKA in invasive trophoblasts: JAR choriocarcinoma cell-line and 6-8 w first trimester trophoblasts. Methods The effect of Forskolin (PKA on MMP-2 expression was assessed by Northern Blot and RT-PCR. Possible transcription factors binding to consensus MMP-2 promoter sequences in response to Forskolin, were detected by EMSA binding assay and their expression assessed by western blot analysis. Antisense transfection of relevant transcription factors was performed and the inhibitory effect assessed on MMP-2 expression (RT-PCR, secretion (zymography and trophoblast invasiveness (transwell migration assay. Results We found that Forskolin increased MMP-2 mRNA in JAR cells within 24 hours, and induced binding to p53, Ets, C/EBP and AP-2. Transcription factors Ets-2, phospho- p53, C/EBP epsilon, C/EBP lambda and AP-2 alpha bound to their respective binding sequences in response to Forskolin and the expressions of these transcription factors were all elevated in Forskolin- treated cells. Inhibition of Ets-2 and p53 reduced MMP-2 expression, secretion and invasiveness of Forskolin treated cells. Conclusion MMP-2 is regulated by PKA through several binding sites and transcription factors including Ets-2, p53, C/EBP, C/EBP lambda and AP-2 alpha. Ets-2 and p53 mediate cAMP- induced trophoblast invasiveness, through regulation of MMP-2.

  4. Apoptosis and proliferative activity of non-Hodgkin's lymphoma: correlation with Bcl-2 and P53 protein expression

    Tumor growth in a given neoplasm is the net result of cell proliferation and cell loss, and apoptosis is the most significant component of continuous cell loss in most tumors. In this study, we examined non-Hodgkin's lymphoma (NHL, n = 67) immunohistochemically for the presence of Bcl-2 oncoprotein and P53 protein and compared apoptotic indices (Als) and Ki-67 proliferative indices (percentages of Ki-67 positive cells). 67 patients with NHL were evaluated: 3 low-grade and 64 intermediate-grade. The phenotype was determined in 65 cases: 47 (70%) were B cell type and 18 (27%) were T cell type. Als and Ki-67 proliferative indices were determined immunohistochemically and the overexpression of P53 and Bcl-2 protein were also evaluated. The overexpressions of Bcl-2 protein and P53 protein were found in 40% (26/65) and 31% (20/65). The Al ranged from 0% to 15% (mean 2.61, median 1.2). Cellular Bcl-2, which counteracts apoptosis, was significantly (ρ = 0.005) associated with Als. Ki-67 proliferative indices ranged from 1% to 91% (mean 55.4), and P53 was significantly (ρ 0.000) associated with Ki-67 proliferative indices. A positive correlation between Als and Ki-67 proliferative indices was revealed (ρ = 0.012) in Bcl-2 positive patients. In NHL, we observed a correlation between Als and Bcl-2 expression, between Ki-67 proliferative indices and P53 expression, and between Als and Ki-67 proliferative indices in Bcl-2 positive patients. Our results suggest that cell apoptosis may be inseparable from cell proliferation during tumor growth

  5. Restoring expression of wild-type p53 suppresses tumor growth but does not cause tumor regression in mice with a p53 missense mutation

    Wang, Yongxing; Suh, Young-Ah; Fuller, Maren Y.; Jackson, James G.; Xiong, Shunbin; Terzian, Tamara; Quintás-Cardama, Alfonso; Bankson, James A.; El-Naggar, Adel K; Lozano, Guillermina

    2011-01-01

    The transcription factor p53 is a tumor suppressor. As such, the P53 gene is frequently altered in human cancers. However, over 80% of the P53 mutations found in human cancers are missense mutations that lead to expression of mutant proteins that not only lack p53 transcriptional activity but exhibit new functions as well. Recent studies show that restoration of p53 expression leads to tumor regression in mice carrying p53 deletions. However, the therapeutic efficacy of restoring p53 expressi...

  6. p53 regulation and activity in mouse embryonic stem cells

    Solozobova, Valeriya

    2010-01-01

    P53 is a tumour development p53. The aim of this work was to study the regulation of p53 in embryonic stem cells and its activation in response to DNA damage. p53 was found that p53 becomes transcriptionally active in ES cells after DNA damage. Embryonic stem cells contain a relatively high amount of p53 protein and p53 RNA. After differentiation p53 level is rapidly downregulated. The high abundance of p53 in undifferentiated ES cells is a result of enhanced translation.

  7. Modulation of p53β and p53γ expression by regulating the alternative splicing of TP53 gene modifies cellular response.

    Marcel, V; Fernandes, K; Terrier, O; Lane, D P; Bourdon, J-C

    2014-09-01

    In addition to the tumor suppressor p53 protein, also termed p53α, the TP53 gene produces p53β and p53γ through alternative splicing of exons 9β and 9γ located within TP53 intron 9. Here we report that both TG003, a specific inhibitor of Cdc2-like kinases (Clk) that regulates the alternative splicing pre-mRNA pathway, and knockdown of SFRS1 increase expression of endogenous p53β and p53γ at mRNA and protein levels. Development of a TP53 intron 9 minigene shows that TG003 treatment and knockdown of SFRS1 promote inclusion of TP53 exons 9β/9γ. In a series of 85 primary breast tumors, a significant association was observed between expression of SFRS1 and α variant, supporting our experimental data. Using siRNA specifically targeting exons 9β/9γ, we demonstrate that cell growth can be driven by modulating p53β and p53γ expression in an opposite manner, depending on the cellular context. In MCF7 cells, p53β and p53γ promote apoptosis, thus inhibiting cell growth. By transient transfection, we show that p53β enhanced p53α transcriptional activity on the p21 and Bax promoters, while p53γ increased p53α transcriptional activity on the Bax promoter only. Moreover, p53β and p53γ co-immunoprecipitate with p53α only in the presence of p53-responsive promoter. Interestingly, although p53β and p53γ promote apoptosis in MCF7 cells, p53β and p53γ maintain cell growth in response to TG003 in a p53α-dependent manner. The dual activities of p53β and p53γ isoforms observed in non-treated and TG003-treated cells may result from the impact of TG003 on both expression and activities of p53 isoforms. Overall, our data suggest that p53β and p53γ regulate cellular response to modulation of alternative splicing pre-mRNA pathway by a small drug inhibitor. The development of novel drugs targeting alternative splicing process could be used as a novel therapeutic approach in human cancers. PMID:24926616

  8. p53-dependent activation of microRNA-34a in response to etoposide-induced DNA damage in osteosarcoma cell lines not impaired by dominant negative p53 expression.

    Chiara Novello

    Full Text Available Osteosarcoma (OS is the most common primary malignant bone tumor and prevalently occurs in the second decade of life. Etoposide, a chemotherapeutic agent used in combined treatments of recurrent human OS, belongs to the topoisomerase inhibitor family and causes DNA breakage. In this study we evaluated the cascade of events determined by etoposide-induced DNA damage in OS cell lines with different p53 status focusing on methylation status and expression of miR-34a that modulate tumor cell growth and cell cycle progression. Wild-type p53 U2-OS cells and U2-OS cells expressing dominant-negative form of p53 (U2- OS175 were more sensitive to etoposide than p53-deficient MG63 and Saos-2 cells, showing increased levels of unmethylated miR-34a, reduced expression of CDK4 and cell cycle arrest in G1 phase. In contrast, MG63 and Saos-2 cell lines presented aberrant methylation of miR-34a promoter gene with no miR-34a induction after etoposide treatment, underlining the close connection between p53 expression and miR-34a methylation status. Consistently, in p53siRNA transfected U2-OS cells we observed loss of miR-34a induction after etoposide exposure associated with a partial gain of gene methylation and cell cycle progress towards G2/M phase. Our results suggest that the open and unmethylated conformation of the miR-34a gene may be regulated by p53 able to bind the gene promoter. In conclusion, cell response to etoposide-induced DNA damage was not compromised in cells with dominant-negative p53 expression.

  9. Gene expression profiles resulting from stable loss of p53 mirrors its role in tissue differentiation.

    Oliver Couture

    Full Text Available The tumor suppressor gene p53 is involved in a variety of cellular activities such as cellular stress responses, cell cycle regulation and differentiation. In our previous studies we have shown p53's transcription activating role to be important in osteoblast differentiation. There is still a debate in the literature as to whether p53 inhibits or promotes differentiation. We have found p53 heterozygous mice to show a p53 dependency on some bone marker gene expression that is absent in knockout mice. Mice heterozygous for p53 also show a higher incidence of osteosarcomas than p53 knockout mice. This suggests that p53 is able to modify the environment within osteoblasts. In this study we compare changes in gene expression resulting after either a transient or stable reduction in p53. Accordingly we reduced p53 levels transiently and stably in C2C12 cells, which are capable of both myoblast and osteoblast differentiation, and compared the changes in gene expression of candidate genes regulated by the p53 pathway. Using a PCR array to assay for p53 target genes, we have found different expression profiles when comparing stable versus transient knockdown of p53. As expected, several genes with profound changes after transient p53 loss were related to apoptosis and cell cycle regulation. In contrast, stable p53 loss produced a greater change in MyoD and other transcription factors with tissue specific roles, suggesting that long term loss of p53 affects tissue homeostasis to a greater degree than changes resulting from acute loss of p53. These differences in gene expression were validated by measuring promoter activity of different pathway specific genes involved in differentiation. These studies suggest that an important role for p53 is context dependent, with a stable reduction in p53 expression affecting normal tissue physiology more than acute loss of p53.

  10. Quercetin Enhances the Antitumor Activity of Trichostatin A through Upregulation of p53 Protein Expression In Vitro and In Vivo

    Chan, Shu-Ting; Yang, Nae-Cherng; Huang, Chin-Shiu; Liao, Jiunn-Wang; Yeh, Shu-Lan

    2013-01-01

    This study investigated the effects of quercetin on the anti-tumor effect of trichostatin A (TSA), a novel anticancer drug, in vitro and in vivo and the possible mechanisms of these effects in human lung cancer cells. We first showed that quercetin (5 µM) significantly increased the growth arrest and apoptosis in A549 cells (expressing wild-type p53) induced by 25 ng/mL of (82.5 nM) TSA at 48 h by about 25% and 101%, respectively. However, such enhancing effects of quercetin (5 µM) were not s...

  11. L-GILZ binds p53 and MDM2 and suppresses tumor growth through p53 activation in human cancer cells

    Ayroldi, E; Petrillo, M G; Bastianelli, A; Marchetti, M C; Ronchetti, S; Nocentini, G; Ricciotti, L; Cannarile, L; Riccardi, C

    2014-01-01

    The transcription factor p53 regulates the expression of genes crucial for biological processes such as cell proliferation, metabolism, cell repair, senescence and apoptosis. Activation of p53 also suppresses neoplastic transformations, thereby inhibiting the growth of mutated and/or damaged cells. p53-binding proteins, such as mouse double minute 2 homolog (MDM2), inhibit p53 activation and thus regulate p53-mediated stress responses. Here, we found that long glucocorticoid-induced leucine z...

  12. Activation and activities of the p53 tumour suppressor protein

    Bálint, É; Vousden, K H

    2001-01-01

    The p53 tumour suppressor protein inhibits malignant progression by mediating cell cycle arrest, apoptosis or repair following cellular stress. One of the major regulators of p53 function is the MDM2 protein, and multiple forms of cellular stress activate p53 by inhibiting the MDM2-mediated degradation of p53. Mutations in p53, or disruption of the pathways that allow activation of p53, seem to be a general feature of all cancers. Here we review recent advances in our understanding of the pat...

  13. P53 FUSION PROTEIN EXPRESSION IN PROKARYOTE AND PREPARATION OF MONOCLONAL ANTIBODY TO P53

    Liu Caiyun; Shou Chengchao; Sun Sulian; ZhangLei; Zeng Li

    1998-01-01

    Objective: Conventional immunohistochemistry (IHC) is available to assess P53 mutations, and expensive imported anti-P53 monoclonal antibody has been used in China, it is necessary to study a new monoclonal antibody.Methods: The P53 DNA fragment enconding N-terminal 180 amiao acide was obtained by PCR and was cloned into PGEX-2T plasmid expressing glutathione S-transferase (GST). The P53-GST fusion protein expressed by JM109was used for immunizing BALB/C mice. We have raised one hybridoma strain secreting McAb to human P53(named M126). Results: The IHC analysis of 52paraffin-embedded sections from human breast cancer with M126 and PAB1801 (Zymed Co.) has showed that the positive immunoreactions were 25 cases (48%) and 22cases (42.3%) respectively. The staining of M126 was stronger and preferable to PAB1801. Conclusion: M126can be instead of PAB1801 for studying immunohistochemical analysis on P53 Protein.

  14. Mutant p53: multiple mechanisms define biologic activity in cancer

    Michael Paul Kim

    2015-11-01

    Full Text Available The functional importance of p53 as a tumor suppressor gene is evident through its pervasiveness in cancer biology. The p53 gene is the most commonly altered gene in human cancer; however, not all genetic alterations are biologically equivalent. The majority of p53 alterations involve missense mutations that result in the production of mutant p53 proteins. Such mutant p53 proteins lack normal p53 function and may acquire novel functions, often with deleterious effects. Here, we review characterized mechanisms of mutant p53 gain of function in multiple model systems. In addition, we review mutant p53 addiction as emerging evidence suggests that tumors may depend on sustained mutant p53 activity for continued growth. We also discuss the role of p53 in stromal elements and their contribution to tumor initiation and progression. Lastly, current genetic mouse models of mutant p53 are reviewed and their limitations discussed.

  15. Acquisition of p53 mutations in response to the non-genotoxic p53 activator Nutlin-3

    Aziz, Moammir H.; Shen, Hong; Carl G Maki

    2011-01-01

    Wild-type p53 is a stress-responsive tumor suppressor and potent growth inhibitor. Genotoxic stresses (e.g. ionizing and UV radiation or chemotherapeutic drug treatment) can activate p53, but also induce mutations in the P53 gene and thus select for p53-mutated cells. Nutlin-3a (Nutlin) is pre-clinical drug that activates p53 in a non-genotoxic fashion. Nutlin occupies the p53-binding pocket of MDM2, activating p53 by blocking the p53-MDM2 interaction. Because Nutlin neither binds p53 directl...

  16. Knockdown of p53 suppresses Nanog expression in embryonic stem cells

    Highlights: •We investigate the role of p53 in ESCs in the absence of DNA damage. •p53 knockdown suppresses ESC proliferation. •p53 knockdown downregulates Nanog expression. •p53 is essential for mouse ESC self-renewal. -- Abstract: Mouse embryonic stem cells (ESCs) express high levels of cytoplasmic p53. Exposure of mouse ESCs to DNA damage leads to activation of p53, inducing Nanog suppression. In contrast to earlier studies, we recently reported that chemical inhibition of p53 suppresses ESC proliferation. Here, we confirm that p53 signaling is involved in the maintenance of mouse ESC self-renewal. RNA interference-mediated knockdown of p53 induced downregulation of p21 and defects in ESC proliferation. Furthermore, p53 knockdown resulted in a significant downregulation in Nanog expression at 24 and 48 h post-transfection. p53 knockdown also caused a reduction in Oct4 expression at 48 h post-transfection. Conversely, exposure of ESCs to DNA damage caused a higher reduction of Nanog expression in control siRNA-treated cells than in p53 siRNA-treated cells. These data show that in the absence of DNA damage, p53 is required for the maintenance of mouse ESC self-renewal by regulating Nanog expression

  17. Knockdown of p53 suppresses Nanog expression in embryonic stem cells

    Abdelalim, Essam Mohamed, E-mail: emohamed@qf.org.qa [Qatar Biomedical Research Institute, Qatar Foundation, Doha 5825 (Qatar); Molecular Neuroscience Research Center, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, Shiga 520-2192 (Japan); Department of Cytology and Histology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia (Egypt); Tooyama, Ikuo [Molecular Neuroscience Research Center, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, Shiga 520-2192 (Japan)

    2014-01-10

    Highlights: •We investigate the role of p53 in ESCs in the absence of DNA damage. •p53 knockdown suppresses ESC proliferation. •p53 knockdown downregulates Nanog expression. •p53 is essential for mouse ESC self-renewal. -- Abstract: Mouse embryonic stem cells (ESCs) express high levels of cytoplasmic p53. Exposure of mouse ESCs to DNA damage leads to activation of p53, inducing Nanog suppression. In contrast to earlier studies, we recently reported that chemical inhibition of p53 suppresses ESC proliferation. Here, we confirm that p53 signaling is involved in the maintenance of mouse ESC self-renewal. RNA interference-mediated knockdown of p53 induced downregulation of p21 and defects in ESC proliferation. Furthermore, p53 knockdown resulted in a significant downregulation in Nanog expression at 24 and 48 h post-transfection. p53 knockdown also caused a reduction in Oct4 expression at 48 h post-transfection. Conversely, exposure of ESCs to DNA damage caused a higher reduction of Nanog expression in control siRNA-treated cells than in p53 siRNA-treated cells. These data show that in the absence of DNA damage, p53 is required for the maintenance of mouse ESC self-renewal by regulating Nanog expression.

  18. Constitutive CCND1/CDK2 activity substitutes for p53 loss, or MYC or oncogenic RAS expression in the transformation of human mammary epithelial cells.

    Damian J Junk

    Full Text Available Cancer develops following the accumulation of genetic and epigenetic alterations that inactivate tumor suppressor genes and activate proto-oncogenes. Dysregulated cyclin-dependent kinase (CDK activity has oncogenic potential in breast cancer due to its ability to inactivate key tumor suppressor networks and drive aberrant proliferation. Accumulation or over-expression of cyclin D1 (CCND1 occurs in a majority of breast cancers and over-expression of CCND1 leads to accumulation of activated CCND1/CDK2 complexes in breast cancer cells. We describe here the role of constitutively active CCND1/CDK2 complexes in human mammary epithelial cell (HMEC transformation. A genetically-defined, stepwise HMEC transformation model was generated by inhibiting p16 and p53 with shRNA, and expressing exogenous MYC and mutant RAS. By replacing components of this model, we demonstrate that constitutive CCND1/CDK2 activity effectively confers anchorage independent growth by inhibiting p53 or replacing MYC or oncogenic RAS expression. These findings are consistent with several clinical observations of luminal breast cancer sub-types that show elevated CCND1 typically occurs in specimens that retain wild-type p53, do not amplify MYC, and contain no RAS mutations. Taken together, these data suggest that targeted inhibition of constitutive CCND1/CDK2 activity may enhance the effectiveness of current treatments for luminal breast cancer.

  19. Aging-Associated Truncated Form of p53 Interacts with Wild-Type p53 and Alters p53 Stability, Localization, and Activity

    Moore, Lynette; Lu, Xiongbin; Ghebranious, Nader; Tyner, Stuart; Donehower, Lawrence A.

    2007-01-01

    Evidence has accumulated that p53, a prototypical tumor suppressor, may also influence aspects of organismal aging. We have previously described a p53 mutant mouse model, the p53+/m mouse, which is cancer resistant yet exhibits reduced longevity and premature aging phenotypes. p53+/m mice express one full length p53 allele and one truncated p53 allele that is translated into a C-terminal fragment of p53 termed the M protein. The augmented cancer resistance and premature aging phenotypes in th...

  20. Urokinase Expression by Tumor Suppressor Protein p53: A Novel Role in mRNA Turnover

    Shetty, Praveenkumar; Velusamy, Thirunavukkarasu; Bhandary, Yashodhar P.; Shetty, Rashmi S.; Liu, Ming-Cheh; Shetty, Sreerama

    2008-01-01

    Lung carcinoma (H1299) cells deficient in p53 (p53−/−) express large amounts of urokinase-type plasminogen activator (uPA) protein and uPA mRNA, and exhibit slower degradation of uPA mRNA than that of p53-expressing nonmalignant Beas2B human airway epithelial cells. Expression of p53 protein in H1299 cells, upon transfection with p53 cDNA, suppressed basal as well as uPA-induced expression of uPA protein in both conditioned media and cell lysates, and decreased the level of steady-state uPA m...

  1. Δ122p53, a mouse model of Δ133p53α, enhances the tumor-suppressor activities of an attenuated p53 mutant

    Slatter, T L; Hung, N. Van; Bowie, S; Campbell, H.; Rubio, C; Speidel, D; Wilson, M.; Baird, M.; Royds, J. A.; Braithwaite, A W

    2015-01-01

    Growing evidence suggests the Δ133p53α isoform may function as an oncogene. It is overexpressed in many tumors, stimulates pathways involved in tumor progression, and inhibits some activities of wild-type p53, including transactivation and apoptosis. We hypothesized that Δ133p53α would have an even more profound effect on p53 variants with weaker tumor-suppressor capability. We tested this using a mouse model heterozygous for a Δ133p53α-like isoform (Δ122p53) and a p53 mutant with weak tumor-...

  2. Expression of TP53 Isoforms p53β or p53γ Enhances Chemosensitivity in TP53null Cell Lines

    Elisabeth Silden; Hjelle, Sigrun M; Line Wergeland; André Sulen; Vibeke Andresen; Jean-Christophe Bourdon; Micklem, David R; Emmet McCormack; Bjørn Tore Gjertsen

    2013-01-01

    The carboxy-terminal truncated p53 alternative spliced isoforms, p53β and p53γ, are expressed at disparate levels in cancer and are suggested to influence treatment response and therapy outcome. However, their functional role in cancer remains to be elucidated. We investigated their individual functionality in the p53(null) background of cell lines H1299 and SAOS-2 by stable retroviral transduction or transient transfection. Expression status of p53β and p53γ protein was found to correlate wi...

  3. Expression of TP53 Isoforms p53β or p53γ Enhances Chemosensitivity in TP53null Cell Lines

    Silden, Elisabeth; Hjelle, Sigrun M; Wergeland, Line; Sulen, André; Andresen, Vibeke; Bourdon, Jean-Christophe; Micklem, David R.; McCormack, Emmet; Gjertsen, Bjørn Tore

    2013-01-01

    The carboxy-terminal truncated p53 alternative spliced isoforms, p53β and p53γ, are expressed at disparate levels in cancer and are suggested to influence treatment response and therapy outcome. However, their functional role in cancer remains to be elucidated. We investigated their individual functionality in the p53null background of cell lines H1299 and SAOS-2 by stable retroviral transduction or transient transfection. Expression status of p53β and p53γ protein was found to correlate with...

  4. Analysis of p53 mutants for transcriptional activity.

    Raycroft, L.; Schmidt, J. R.; Yoas, K; Hao, M M; Lozano, G.

    1991-01-01

    The wild-type p53 protein functions to suppress transformation, but numerous mutant p53 proteins are transformation competent. To examine the role of p53 as a transcription factor, we made fusion proteins containing human or mouse p53 sequences fused to the DNA binding domain of a known transcription factor, GAL4. Human and mouse wild-type p53/GAL4 specifically transactivated expression of a chloramphenicol acetyltransferase reporter in HeLa, CHO, and NIH 3T3 cells. Several mutant p53 protein...

  5. Expression of TP53 isoforms p53β or p53γ enhances chemosensitivity in TP53(null cell lines.

    Elisabeth Silden

    Full Text Available The carboxy-terminal truncated p53 alternative spliced isoforms, p53β and p53γ, are expressed at disparate levels in cancer and are suggested to influence treatment response and therapy outcome. However, their functional role in cancer remains to be elucidated. We investigated their individual functionality in the p53(null background of cell lines H1299 and SAOS-2 by stable retroviral transduction or transient transfection. Expression status of p53β and p53γ protein was found to correlate with increased response to camptothecin and doxorubicin chemotherapy. Decreased DNA synthesis and clonogenicity in p53β and p53γ congenic H1299 was accompanied by increased p21((CIP1/WAF1, Bax and Mdm2 proteins. Chemotherapy induced p53 isoform degradation, most prominent for p53γ. The proteasome inhibitor bortezomib substantially increased basal p53γ protein level, while the level of p53β protein was unaffected. Treatment with dicoumarol, a putative blocker of the proteasome-related NAD(PH quinone oxidoreductase NQO1, effectively attenuated basal p53γ protein level in spite of bortezomib treatment. Although in vitro proliferation and clonogenicity assays indicated a weak suppressive effect by p53β and p53γ expression, studies of in vivo subcutaneous H1299 tumor growth demonstrated a significantly increased growth by expression of either p53 isoforms. This study suggests that p53β and p53γ share functionality in chemosensitizing and tumor growth enhancement but comprise distinct regulation at the protein level.

  6. Expression of TP53 isoforms p53β or p53γ enhances chemosensitivity in TP53(null) cell lines.

    Silden, Elisabeth; Hjelle, Sigrun M; Wergeland, Line; Sulen, André; Andresen, Vibeke; Bourdon, Jean-Christophe; Micklem, David R; McCormack, Emmet; Gjertsen, Bjørn Tore

    2013-01-01

    The carboxy-terminal truncated p53 alternative spliced isoforms, p53β and p53γ, are expressed at disparate levels in cancer and are suggested to influence treatment response and therapy outcome. However, their functional role in cancer remains to be elucidated. We investigated their individual functionality in the p53(null) background of cell lines H1299 and SAOS-2 by stable retroviral transduction or transient transfection. Expression status of p53β and p53γ protein was found to correlate with increased response to camptothecin and doxorubicin chemotherapy. Decreased DNA synthesis and clonogenicity in p53β and p53γ congenic H1299 was accompanied by increased p21((CIP1/WAF1)), Bax and Mdm2 proteins. Chemotherapy induced p53 isoform degradation, most prominent for p53γ. The proteasome inhibitor bortezomib substantially increased basal p53γ protein level, while the level of p53β protein was unaffected. Treatment with dicoumarol, a putative blocker of the proteasome-related NAD(P)H quinone oxidoreductase NQO1, effectively attenuated basal p53γ protein level in spite of bortezomib treatment. Although in vitro proliferation and clonogenicity assays indicated a weak suppressive effect by p53β and p53γ expression, studies of in vivo subcutaneous H1299 tumor growth demonstrated a significantly increased growth by expression of either p53 isoforms. This study suggests that p53β and p53γ share functionality in chemosensitizing and tumor growth enhancement but comprise distinct regulation at the protein level. PMID:23409163

  7. Human papillomavirus 18 E6 inhibits phosphorylation of p53 expressed in HeLa cells

    Ajay Amrendra K

    2012-01-01

    Full Text Available Abstract Background In HPV infected cells p53 function is abrogated by E6 and even ectopically expressed p53 is unable to perform tumor suppressor functions. In addition to facilitating its degradation, E6 may also inhibit p53 transactivity, though the mechanisms are still poorly understood. It has been reported that inhibition of p300, an acetyltransferase responsible for p53 acetylation is inactivated by E6. Activation of overexpressed p53 to cause cell growth inhibition is facilitated by its phosphorylation. Previously, we reported that non-genotoxically overexpressed p53 in HeLa cells needs to be phosphorylated to perform its cell growth inhibitory functions. Since over expressed p53 by itself was not activated, we hypothesized an inhibitory role for E6. Results Majority of reports proposes E6 mediated degradation of p53 as a possible reason for its inactivation. However, results presented here for the first time demonstrate that overexpressed p53 is not directly associated with E6 and therefore free, yet it is not functionally active in HPV positive cells. Also, the stability of overexpressed p53 does not seem to be an issue because inhibition of proteasomal degradation did not increase the half-life of overexpressed p53, which is more than endogenous p53. However, inhibition of proteasomal degradation prevents the degradation of endogenous p53. These findings suggest that overexpressed p53 and endogenous p53 are differentially subjected to proteasomal degradation and the reasons for this discrepancy remain unclear. Our studies demonstrate that p53 over expression has no effect on anchorage independent cell-growth and E6 nullifies its cell growth inhibitory effect. E6 overexpression abrogates OA induced p53 occupancy on the p21 promoter and cell death as well. E6 did not decrease p53 protein but phospho-p53 level was significantly reduced. Conclusion We report for the first time that E6 de-activates p53 by inhibiting its phosphorylation

  8. Immunohistochemical Estimates of Angiogenesis, Proliferative Activity, p53 Expression, and Multiple Drug Resistance Have No Prognostic Impact in Osteosarcoma: A Comparative Clinicopathological Investigation

    Sørensen, Flemming Brandt; Jensen, Kenneth; Vaeth, Michael;

    2008-01-01

    (P = .64) and p53 (P > .32), whereas the MIB-1 index was reduced in the post-chemotherapy specimens (P = .02). The overall, disease-specific survival was 47%, increasing to 54% in patients receiving pre-operative chemotherapy. Statistical analyses showed prognostic impact exclusively by patient age...... regarding angiogenesis (CD34), proliferative activity (MIB-1), and the expression of p53 and MDR (P-glycoprotein (Pgp); clones JSB-1, C494, and MRK16). Quantitative and semiquantitative scores of immunoreactive cells were analyzed statistically along with retrospectively obtained clinicopathologic variables....... Results. Chemotherapy reduced the rate of amputations (P = .00002). The Pgp was overexpressed (score >/=2) in 48% of the primary, diagnostic biopsies, and high Pgp correlated with high Pgp in postsurgical specimens (P = .003). In contrast, no such associations were disclosed for estimates of angiogenesis...

  9. p53 spreads out further:suppression of EMT and stemness by activating miR-200c expression

    J(o)rg Schubert; Thomas Brabletz

    2011-01-01

    @@ There is no need to emphasize the overwhelming importance of p53 for crucial cellular processes and of genetic alterations resulting from its loss of function or a dominant oncogenic mutant in many human cancer types.These functions are well described and include control of cell cycle progression, apoptosis, senescence, DNA-repair mechanisms and autophagy[1].

  10. High-level expression of wild-type p53 in melanoma cells is frequently associated with inactivity in p53 reporter gene assays.

    Roland Houben

    Full Text Available BACKGROUND: Inactivation of the p53 pathway that controls cell cycle progression, apoptosis and senescence, has been proposed to occur in virtually all human tumors and p53 is the protein most frequently mutated in human cancer. However, the mutational status of p53 in melanoma is still controversial; to clarify this notion we analysed the largest series of melanoma samples reported to date. METHODOLOGY/PRINCIPAL FINDINGS: Immunohistochemical analysis of more than 180 melanoma specimens demonstrated that high levels of p53 are expressed in the vast majority of cases. Subsequent sequencing of the p53 exons 5-8, however, revealed only in one case the presence of a mutation. Nevertheless, by means of two different p53 reporter constructs we demonstrate transcriptional inactivity of wild type p53 in 6 out of 10 melanoma cell lines; the 4 other p53 wild type melanoma cell lines exhibit p53 reporter gene activity, which can be blocked by shRNA knock down of p53. CONCLUSIONS/SIGNIFICANCE: In melanomas expressing high levels of wild type p53 this tumor suppressor is frequently inactivated at transcriptional level.

  11. Defective accumulation of p53 protein in x-irradiated human tumor cells with low proteasome activity

    Full text: We established p53-inducible clones, 99-p53 His, by transfecting an ecdyson-inducible vector containing the wild type p53 gene into p53-null H1299, a human non-small cell lung carcinoma cell line. In contrast to normal human diploid cells, in which p53 is accumulated after X-irradiation, the level of p53 protein did not change following 4 Gy of X-rays. We found that phosphorylation of p53 at Ser15 and Ser20 was induced similarly between 99-p53 His cells and normal human cells. However, p53 was more resistant to degradation in 99-p53 His cells, and its level did not change after treatment with cycloheximide, a protein synthesis inhibitor, while p53 protein in normal human cells was degraded rapidly. Furthermore, proteasome inhibitors, ALLN, MG115, and MG132 accumulated p53 protein significantly in normal human cells, but there was no accumulation of p53 protein in 99-p53 His cells. These results indicate that DNA damage signaling through ATM is functional in 99-p53 His cells, but they have defect in p53 degradation pathway. Thus, low proteasome activity in 99-p53 His cells could be a reason for the defective accumulation of p53 protein following X-irradiation. Present study shows that proteasome activity is an important determinant of p53 stability, when the wild-type p53 gene is expressed in p53-null cancer cells

  12. Genome wide expression profiling of p53 regulated miRNAs in neuroblastoma

    Rihani, Ali; Van Goethem, Alan; Ongenaert, Maté; De Brouwer, Sara; Volders, Pieter-Jan; Agarwal, Saurabh; De Preter, Katleen; Mestdagh, Pieter; Shohet, Jason; Speleman, Frank; Vandesompele, Jo; VAN MAERKEN, TOM

    2015-01-01

    Restoration of the antitumor activity of p53 could offer a promising approach for the treatment of neuroblastoma. MicroRNAs (miRNAs) are important mediators of p53 activity, but their role in the p53 response has not yet been comprehensively addressed in neuroblastoma. Therefore, we set out to characterize alterations in miRNA expression that are induced by p53 activation in neuroblastoma cells. Genome-wide miRNA expression analysis showed that miR-34a-5p, miR-182-5p, miR-203a, miR-222-3p, an...

  13. Human neuroblastoma cells with acquired resistance to the p53 activator RITA retain functional p53 and sensitivity to other p53 activating agents

    Michaelis, M.; Rothweiler, F.; Agha, B.; Barth, S.; Voges, Y.; Loeschmann, N.; von Deimling, A.; Breitling, R.; Doerr, H. Wilhelm; Roedel, F.; Speidel, D.; Cinatl, J.; Cinatl Jr., J.; Stephanou, A.

    2012-01-01

    Adaptation of wild-type p53 expressing UKF-NB-3 cancer cells to the murine double minute 2 inhibitor nutlin-3 causes de novo p53 mutations at high frequency (13/20) and multi-drug resistance. Here, we show that the same cells respond very differently when adapted to RITA, a drug that, like nutlin-3,

  14. EXPRESSION OF p16 AND p53 IN GASTRIC CARCINOMA

    2003-01-01

    Objective:To investigate the clinical significance of p53 and p16 expression in gastric carcinoma with special reference to the prognosis.Methods:One hundred and fifty-two patients with gastric carcinoma undergoing operation in our hospital between 1991 and 1998 were evaluated for expression of p53 and p16 in formalin-fixed and paraffin-embedded tumor tissue utilizing Avidin-Biotin immunohistochemistry techniques. Statistical correlations with stage, histological type, differentiation degree, location, size, and overall survival were done. The Cox proportional hazard model was also performed to evaluate which factors had an independent prognostic value.Results:In 152 cases of resected gastric cancer, 110 (72.4%) were p16 positive and 49 (32.2%) showed p53 overexpression. Differences were observed in the frequency of p16 positivity with respect to age, gender and tumor size. The frequency of p53 positivity cells in well-differentiated tumors was significantly higher than that in poorly differentiated tumors (41.9% vs. 25.6%; P= 0.034). In a multivariate analysis, tumor TNM stage, perioperation chemotherapy and the expression of p16 were independent prognostic factors in gastric cancer.Conclusions:The results of the current study suggest that expression of p16 may be a useful prognostic factor for patients with gastric carcinoma, but the expression of p53 as detected by immunohistochemistry were of no value in predicting the prognosis of patients with gastric carcinoma independently.

  15. Allele specific gain-of-function activity of p53 mutants in lung cancer cells

    Vaughan, Catherine A.; Frum, Rebecca; Pearsall, Isabella; Singh, Shilpa; Windle, Brad; Yeudall, Andrew; Deb, Swati P.; Deb, Sumitra

    2012-01-01

    p53 mutations are mostly single amino acid changes resulting in expression of a stable mutant protein with “gain of function” (GOF) activity having a dominant oncogenic role rather than simple loss of function of wild-type p53. Knock-down of mutant p53 in human lung cancer cell lines with different endogenous p53 mutants results in loss of GOF activity as shown by lowering of cell growth rate. Two lung cancer cell lines, ABC1 and H1437 carrying endogenous mutants p53–P278S and –R267P, both sh...

  16. p53 inactivation upregulates p73 expression through E2F-1 mediated transcription.

    Chaitali Tophkhane

    Full Text Available While p73 overexpression has been associated with increased apoptosis in cancer tissues, p73 overexpressing tumors appear to be of high grade malignancy. Why this putative tumor suppressor is overexpressed in cancer cells and what the function of overexpressed p73 is in breast cancers are critical questions to be addressed. By investigating the effect of p53 inactivation on p73 expression, we found that both protein and mRNA levels of TAp73 were increased in MCF-7/p53siRNA cells, MCF-7/p53mt135 cells and HCT-116/p53-/- cells, as compared to wild type control, suggesting that p53 inactivation by various forms upregulates p73. We showed that p53 knockdown induced p73 was mainly regulated at the transcriptional level. However, although p53 has a putative binding site in the TAp73 promoter, deletion of this binding site did not affect p53 knockdown mediated activation of TAp73 promoter. Chromatin immuno-precipitation (ChIP data demonstrated that loss of p53 results in enhanced occupancy of E2F-1 in the TAp73 promoter. The responsive sequence of p53 inactivation mediated p73 upregulation was mapped to the proximal promoter region of the TAp73 gene. To test the role of E2F-1 in p53 inactivation mediated regulation of p73 transcription, we found that p53 knockdown enhanced E2F-1 dependent p73 transcription, and mutations in E2F-1 binding sites in the TAp73 promoter abrogated p53 knockdown mediated activation of TAp73 promoter. Moreover, we demonstrated that p21 is a mediator of p53-E2F crosstalk in the regulation of p73 transcription. We concluded that p53 knockdown/inactivation may upregulate TAp73 expression through E2F-1 mediated transcriptional regulation. p53 inactivation mediated upregulation of p73 suggests an intrinsic rescuing mechanism in response to p53 mutation/inactivation. These findings support further analysis of the correlation between p53 status and p73 expression and its prognostic/predictive significance in human cancers.

  17. Using targeted transgenic reporter mice to study promoter-specific p53 transcriptional activity

    Goh, Amanda M.; Lim, Chin Yan; Chiam, Poh Cheang; Mann, Michael B.; Mann, Karen M.; Menendez, Sergio; Lane, David P.

    2012-01-01

    The p53 transcription factor modulates gene expression programs that induce cell cycle arrest, senescence, or apoptosis, thereby preventing tumorigenesis. However, the mechanisms by which these fates are selected are unclear. Our objective is to understand p53 target gene selection and, thus, enable its optimal manipulation for cancer therapy. We have generated targeted transgenic reporter mice in which EGFP expression is driven by p53 transcriptional activity at a response element from either the p21 or Puma promoter, which induces cell cycle arrest/senescence and apoptosis, respectively. We demonstrate that we could monitor p53 activity in vitro and in vivo and detect variations in p53 activity depending on the response element, tissue type, and stimulus, thereby validating our reporter system and illustrating its utility for preclinical drug studies. Our results also show that the sequence of the p53 response element itself is sufficient to strongly influence p53 target gene selection. Finally, we use our reporter system to provide evidence for p53 transcriptional activity during early embryogenesis, showing that p53 is active as early as embryonic day 3.5 and that p53 activity becomes restricted to embryonic tissue by embryonic day 6.5. The data from this study demonstrate that these reporter mice could serve as powerful tools to answer questions related to basic biology of the p53 pathway, as well as cancer therapy and drug discovery. PMID:22307631

  18. Expression of p53 protein in pituitary adenomas

    Oliveira M.C.

    2002-01-01

    Full Text Available Inactivating mutations of TP53, a tumor suppressor gene, are associated with abnormal cell proliferation. Although p53 expression is common in many human malignancies, p53 protein has seldom been evaluated in pituitary tumors. When detected, the percentage of p53-positive cells is low, and, in general, it is exclusive for invasive lesions. The aim of the present study was to use immunohistochemistry to determine the presence of p53 protein in pituitary adenomas from tumor samples of 163 surgeries performed in 148 patients (40% male, 60% female. In 35% of the cases the adenoma was nonfunctional, while in the others it was associated with PRL, GH and/or ACTH endocrine hypersecretion syndrome. Macroadenomas were observed in 83.2% of the cases with available neuroimage evaluation, of which 28% invaded the cavernous, sphenoid and/or ethmoidal sinus, bone, third ventricle or subfrontal lobe. p53 protein was detected in 2/148 patients (1.3%. Immunohistochemistry was positive for PRL and GH in these cases. Due to the high percentage of invasive pituitary adenomas found in our study, the low frequency of p53 detection suggests that it is inadequate as a routine marker for aggressiveness and as a predictive factor of tumor behavior.

  19. P53 Gene Mutation and Expression of MDM2, P53, P16 Protein and their Relationship in Human Glioma

    CUI Wen; WU Renliang; CAO Huiling; GAO Jifa; WANG Xu; REN Qiwei

    2005-01-01

    To investigate the effect of P53 protein accumulation and p53 gene mutation in the pathogenesis of glioma and to study the role of MDM2, P53 and P16 protein in glioma formation and progression and their relationship with each other, LSAB immunohistochemical staining method and non-isotopic PCR-SSCP techniques were used to detect the expression of MDM2, P53 and P16 pro tein and p53 gene mutation in 48 cases of gliomas. The results showed that the positive expression rate of MDM2, P53 and the negative rate of P16 was 22.9 %, 41.7 % and 60.4 %, respectively.The latter two in high grade (grade Ⅲ , Ⅳ) gliomas had a significantly higher rate than in the low grade (grade Ⅱ ) gliomas. Moreover, the co-expression of MDM2 and P53 protein was confirmed in only 1 of 48 cases. No significant difference was found in the rate of the expression of MDM2 between high grade and low grade gliomas (P>0.1) . PCR SSCP results showed that mutation of 5-8 exons of p53 gene was detected in 17 out of 48 cases (35.42 %) . Mutation was detected in 16of 20 cases of positive p53 expression, and another one was detected in 28 cases of negative expression cases. The correlation between p53 mutation and p53 immunopositivity was observed in 89.6% of the cases. P53 gene mutation and the level of MDM2, P53 and P16 protein were not related to age, gender of the patients, tumor location and size. It is concluded that the mutation of p53 and deletion of p16 might play important roles in the tumorigenesis of gliomas and it was significantly associated with the grade of tumor differentiation. P53 protein accumulation can indirectly reflect p53 mutation. MDM2 amplification and overexpression might be an early event in the growth of human gliomas.

  20. P53 suppresses expression of the 14-3-3gamma oncogene

    Qi Wenqing

    2011-08-01

    Full Text Available Abstract Background 14-3-3 proteins are a family of highly conserved proteins that are involved in a wide range of cellular processes. Recent evidence indicates that some of these proteins have oncogenic activity and that they may promote tumorigenesis. We previously showed that one of the 14-3-3 family members, 14-3-3gamma, is over expressed in human lung cancers and that it can induce transformation of rodent cells in vitro. Methods qRTPCR and Western blot analysis were performed to examine 14-3-3gamma expression in non-small cell lung cancers (NSCLC. Gene copy number was analyzed by qPCR. P53 mutations were detected by direct sequencing and also by western blot. CHIP and yeast one hybrid assays were used to detect p53 binding to 14-3-3gamma promoter. Results Quantitative rtPCR results showed that the expression level of 14-3-3gamma was elevated in the majority of NSCLC that we examined which was also consistent with protein expression. Further analysis of the expression pattern of 14-3-3gamma in lung tumors showed a correlation with p53 mutations suggesting that p53 might suppress 14-3-3 gamma expression. Analysis of the gamma promoter sequence revealed the presence of a p53 consensus binding motif and in vitro assays demonstrated that wild-type p53 bound to this motif when activated by ionizing radiation. Deletion of the p53 binding motif eliminated p53's ability to suppress 14-3-3gamma expression. Conclusion Increased expression of 14-3-3gamma in lung cancer coincides with loss of functional p53. Hence, we propose that 14-3-3gamma's oncogenic activities cooperate with loss of p53 to promote lung tumorigenesis.

  1. P53 suppresses expression of the 14-3-3gamma oncogene

    14-3-3 proteins are a family of highly conserved proteins that are involved in a wide range of cellular processes. Recent evidence indicates that some of these proteins have oncogenic activity and that they may promote tumorigenesis. We previously showed that one of the 14-3-3 family members, 14-3-3gamma, is over expressed in human lung cancers and that it can induce transformation of rodent cells in vitro. qRTPCR and Western blot analysis were performed to examine 14-3-3gamma expression in non-small cell lung cancers (NSCLC). Gene copy number was analyzed by qPCR. P53 mutations were detected by direct sequencing and also by western blot. CHIP and yeast one hybrid assays were used to detect p53 binding to 14-3-3gamma promoter. Quantitative rtPCR results showed that the expression level of 14-3-3gamma was elevated in the majority of NSCLC that we examined which was also consistent with protein expression. Further analysis of the expression pattern of 14-3-3gamma in lung tumors showed a correlation with p53 mutations suggesting that p53 might suppress 14-3-3 gamma expression. Analysis of the gamma promoter sequence revealed the presence of a p53 consensus binding motif and in vitro assays demonstrated that wild-type p53 bound to this motif when activated by ionizing radiation. Deletion of the p53 binding motif eliminated p53's ability to suppress 14-3-3gamma expression. Increased expression of 14-3-3gamma in lung cancer coincides with loss of functional p53. Hence, we propose that 14-3-3gamma's oncogenic activities cooperate with loss of p53 to promote lung tumorigenesis

  2. Malignant Trigeminal Nerve Sheath Tumor and Anaplastic Astrocytoma Collision Tumor with High Proliferative Activity and Tumor Suppressor P53 Expression

    Maher Kurdi

    2014-01-01

    Full Text Available Background. The synchronous development of two primary brain tumors of distinct cell of origin in close proximity or in contact with each other is extremely rare. We present the first case of collision tumor with two histological distinct tumors. Case Presentation. A 54-year-old woman presented with progressive atypical left facial pain and numbness for 8 months. MRI of the brain showed left middle cranial fossa heterogeneous mass extending into the infratemporal fossa. At surgery, a distinct but intermingled intra- and extradural tumor was demonstrated which was completely removed through left orbitozygomatic-temporal craniotomy. Histopathological examination showed that the tumor had two distinct components: malignant nerve sheath tumor of the trigeminal nerve and temporal lobe anaplastic astrocytoma. Proliferative activity and expressed tumor protein 53 (TP53 gene mutations were demonstrated in both tumors. Conclusions. We describe the first case of malignant trigeminal nerve sheath tumor (MTNST and anaplastic astrocytoma in collision and discuss the possible hypothesis of this rare occurrence. We propose that MTNST, with TP53 mutation, have participated in the formation of anaplastic astrocytoma, or vice versa.

  3. P53 and p73 differ in their ability to inhibit glucocorticoid receptor (GR transcriptional activity

    Nie Linghu

    2006-12-01

    Full Text Available Abstract Background p53 is a tumor suppressor and potent inhibitor of cell growth. P73 is highly similar to p53 at both the amino acid sequence and structural levels. Given their similarities, it is important to determine whether p53 and p73 function in similar or distinct pathways. There is abundant evidence for negative cross-talk between glucocorticoid receptor (GR and p53. Neither physical nor functional interactions between GR and p73 have been reported. In this study, we examined the ability of p53 and p73 to interact with and inhibit GR transcriptional activity. Results We show that both p53 and p73 can bind GR, and that p53 and p73-mediated transcriptional activity is inhibited by GR co-expression. Wild-type p53 efficiently inhibited GR transcriptional activity in cells expressing both proteins. Surprisingly, however, p73 was either unable to efficiently inhibit GR, or increased GR activity slightly. To examine the basis for this difference, a series of p53:p73 chimeric proteins were generated in which corresponding regions of either protein have been swapped. Replacing N- and C-terminal sequences in p53 with the corresponding sequences from p73 prevented it from inhibiting GR. In contrast, replacing p73 N- and C-terminal sequences with the corresponding sequences from p53 allowed it to efficiently inhibit GR. Differences in GR inhibition were not related to differences in transcriptional activity of the p53:p73 chimeras or their ability to bind GR. Conclusion Our results indicate that both N- and C-terminal regions of p53 and p73 contribute to their regulation of GR. The differential ability of p53 and p73 to inhibit GR is due, in part, to differences in their N-terminal and C-terminal sequences.

  4. Using targeted transgenic reporter mice to study promoter-specific p53 transcriptional activity

    Goh, Amanda M.; Lim, Chin Yan; Chiam, Poh Cheang; LI, LING; Mann, Michael B.; Mann, Karen M.; Menendez, Sergio; Lane, David P

    2012-01-01

    The p53 transcription factor modulates gene expression programs that induce cell cycle arrest, senescence, or apoptosis, thereby preventing tumorigenesis. However, the mechanisms by which these fates are selected are unclear. Our objective is to understand p53 target gene selection and, thus, enable its optimal manipulation for cancer therapy. We have generated targeted transgenic reporter mice in which EGFP expression is driven by p53 transcriptional activity at a response element from eithe...

  5. p53 facilitates pRb cleavage in IL-3-deprived cells: novel pro-apoptotic activity of p53.

    Gottlieb, E; Oren, M.

    1998-01-01

    In the interleukin-3 (IL-3)-dependent lymphoid cell line DA-1, functional p53 is required for efficient apoptosis in response to IL-3 withdrawal. Activation of p53 in these cells, by either DNA damage or p53 overexpression, results in a vital growth arrest in the presence of IL-3 and in accelerated apoptosis in its absence. Thus, IL-3 can control the choice between p53-dependent cell-cycle arrest and apoptosis. Here we report that the cross-talk between p53 and IL-3 involves joint control of ...

  6. Induction of wild-type p53 activity in human cancer cells by ribozymes that repair mutant p53 transcripts

    Watanabe, Takashi; Sullenger, Bruce A

    2000-01-01

    Several groups have attempted to develop gene therapy strategies to treat cancer via introduction of the wild-type (wt) p53 cDNA into cancer cells. Unfortunately, these approaches do not result in regulated expression of the p53 gene and do not reduce expression of the mutant p53 that is overexpressed in cancerous cells. These shortcomings may greatly limit the utility of this gene replacement approach. We describe an alternative strategy with trans-splicing ribozymes that can simultaneously ...

  7. The expression of p53 and hsp70 proteins after treatment with Annona muricata Linn leaf for activating apoptotic and lead to homeostasis program of Raji cells

    Okid Parama Astirin; Adi Prayitno; Anif Nur Artanti; Meutia Srikandi Fitria; Dyah Ayu Witianingsih; Dwimei Ayudewandari Pranatami; Suhartono Taat Putra

    2014-01-01

    Purpose: Organic extracts of plant Annonaceae enhances apoptosis in animal cells and get the drives to reach a new homeostasis. The incidence rate of nasopharyngeal cancer in Indonesia is quite high. Protein 53Kd (p53) play a role in apoptosis process, being heat shock protein 70 (hsp70) play a role in homeostasis. The aim of this research is to identify the apoptotic effects of Annona muricata Linn leaf toward Raji cells by observing the p53 and hsp70 expression.Methods: Apoptotic assay was ...

  8. Loss of p53-regulatory protein IFI16 induces NBS1 leading to activation of p53-mediated checkpoint by phosphorylation of p53 SER37.

    Tawara, Hideyuki; Fujiuchi, Nobuko; Sironi, Juan; Martin, Sarah; Aglipay, Jason; Ouchi, Mutsuko; Taga, Makoto; Chen, Phang-Lang; Ouchi, Toru

    2008-01-01

    Our previous results that IFI16 is involved in p53 transcription activity under conditions of ionizing radiation (IR), and that the protein is frequently lost in human breast cancer cell lines and breast adenocarcinoma tissues suggesting that IFI16 plays a crucial role in controlling cell growth. Here, we show that loss of IFI16 by RNA interference in cell culture causes elevated phosphorylation of p53 Ser37 and accumulated NBS1 (nibrin) and p21WAF1, leading to growth retardation. Consistent with these observations, doxycyclin-induced NBS1 caused accumulation of p21WAF1 and increased phosphorylation of p53 Ser37, leading to cell cycle arrest in G1 phase. Wortmannin treatment was found to decrease p53 Ser37 phosphorylation in NBS-induced cells. These results suggest that loss of IFI16 activates p53 checkpoint through NBS1-DNA-PKcs pathway. PMID:17981542

  9. Immunohistochemical expression of protein p53 in neoplasms of the mammary gland in bitches.

    Rodo, A; Malicka, E

    2008-01-01

    The aim of the study was to investigate the presence of protein p53 in correlation with other tumor traits: histological type, tumor grade and proliferative activity. Material for the investigation comprised mammary gland tumours collected from dogs, the patients of veterinary clinics, during surgical procedures, and archival samples. Alltogether 21 adenomas, 31 complex carcinomas, 35 simple carcinomas and 12 solid carcinomas were qualified for further investigation. No protein p53 expression was found in adenomas. Cancers show positive reaction in 32.5%. The highest percent of p53 positive neoplasms was observed in solid carcinomas and neoplasms with the highest degree of histological malignancy. The smallest number showing this expression was observed in adenomas and the highest was characteristic for solid carcinomas. Considering the tumour grading, it was found that an increase in neoplasm malignancy was positively correlated with the number of the cells showing the expression of protein p53. The differences were statistically significant. Statistically significant positive correlations were observed between the proliferative activity and protein p53 expression. Higher accumulation of protein p53 in more malignant neoplasms suggests that mutations of protein p53 can be responsible for higher proliferation in neoplasms with advanced progression of malignancy. PMID:18683536

  10. Analysis of p53 and miRNA expressions after irradiation in glioblastoma cell lines

    Glioblastoma is a malignant brain tumor which is difficult to completely cure by surgical treatment and consequently in attempt for cure it is treated with a combination of radiotherapy and chemotherapy following surgery. Unfortunately however, these procedures are not curative for this type of tumor due to the development of resistance to anticancer drugs and radiation during treatment. P53 is a radiation-resistant factor. It plays an important role in apoptosis regulation. When cells are irradiated DNA is injured; P53 is then activated and it regulates the transcription of the target genes related to apoptosis. However, the p53 gene is defective or mutated in 50% of glioblastoma cases, thereby impairing the transcription activation capability, and thus the P53 apoptosis induction pathway does not function and apoptosis is not induced. Accordingly, the cells are less radiosensitive and show marked resistance to radiation. Apoptosis induction is an important cancer-suppressive function and it determines the sensitivity to treatments, such as chemotherapy and radiotherapy. miRNA which regulates this gene transcription has recently been reported. miRNAs are small RNAs comprised of 21-23 base-pairs. They bind to several proteins to form complexes, and bind to the N-terminal of the target mRNA for the post-transcriptional inhibition of gene expression. In this study, we analyzed the protein expression of P53, Bcl-2, Bax, and Caspase9 and miRNA expression-regulating genes involved in the P53 apoptosis pathway using a P53 mutant, T98G glioblastoma cells, and P53 wild-type A172 glioblastoma cells. Regarding miRNA, the involvement of P53-regulating mi-125b, mi-34a, mi-504, mi-380-5P, mi-885-5P, mi-145, Bax-regulating mi-21, mi-222, and mi-34a, and mi-21-regulating Bcl-2 and Caspase9 was suggested. In particular, P53 and mi-34a expressions in P53 wild-type A172 cells and Bcl-2 and mi-21 expressions in the P53 mutant type were closely involved in the P53 apoptosis induction

  11. The Proteasome Activator PA28γ, a Negative Regulator of p53, Is Transcriptionally Up-Regulated by p53

    Zhen-Xing Wan

    2014-02-01

    Full Text Available PA28γ (also called REGγ, 11Sγ or PSME3 negatively regulates p53 activity by promoting its nuclear export and/or degradation. Here, using the RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE method, we identified the transcription start site of the PA28γ gene. Assessment with the luciferase assay demonstrated that the sequence −193 to +16 is the basal promoter. Three p53 binding sites were found within the PA28γ promoter utilizing a bioinformatics approach and were confirmed by chromatin immunoprecipitation and biotinylated DNA affinity precipitation experiments. The p53 protein promotes PA28γ transcription, and p53-stimulated transcription of PA28γ can be inhibited by PA28γ itself. Our results suggest that PA28γ and p53 form a negative feedback loop, which maintains the balance of p53 and PA28γ in cells.

  12. MYC activates stem-like cell potential in hepatocarcinoma by a p53-dependent mechanism

    Akita, Hirofumi; Marquardt, Jens U; Durkin, Marian E;

    2014-01-01

    biology of hepatic cancer stem cells (CSCs) are undefined. Here, distinct levels of c-MYC over-expression were established by using two dose-dependent tetracycline inducible systems in 4 hepatoma cell lines with different p53 mutational status. The CSCs were evaluated using side-population approach as......-MYC induced a pro-apoptotic program and loss of CSC potential both in vitro and in vivo. Mechanistically, c-MYC induced self-renewal capacity of liver cancer cells was exerted in a p53 dependent manner. Low c-MYC activation increased spheroid formation in p53-deficient tumor cells, whereas p53-dependent...

  13. Xenogeneic human p53 DNA vaccination by electroporation breaks immune tolerance to control murine tumors expressing mouse p53.

    Ruey-Shyang Soong

    Full Text Available The pivotal role of p53 as a tumor suppressor protein is illustrated by the fact that this protein is found mutated in more than 50% of human cancers. In most cases, mutations in p53 greatly increase the otherwise short half-life of this protein in normal tissue and cause it to accumulate in the cytoplasm of tumors. The overexpression of mutated p53 in tumor cells makes p53 a potentially desirable target for the development of cancer immunotherapy. However, p53 protein represents an endogenous tumor-associated antigen (TAA. Immunization against a self-antigen is challenging because an antigen-specific immune response likely generates only low affinity antigen-specific CD8(+ T-cells. This represents a bottleneck of tumor immunotherapy when targeting endogenous TAAs expressed by tumors. The objective of the current study is to develop a safe cancer immunotherapy using a naked DNA vaccine. The vaccine employs a xenogeneic p53 gene to break immune tolerance resulting in a potent therapeutic antitumor effect against tumors expressing mutated p53. Our study assessed the therapeutic antitumor effect after immunization with DNA encoding human p53 (hp53 or mouse p53 (mp53. Mice immunized with xenogeneic full length hp53 DNA plasmid intramuscularly followed by electroporation were protected against challenge with murine colon cancer MC38 while those immunized with mp53 DNA were not. In a therapeutic model, established MC38 tumors were also well controlled by treatment with hp53 DNA therapy in tumor bearing mice compared to mp53 DNA. Mice vaccinated with hp53 DNA plasmid also exhibited an increase in mp53-specific CD8(+ T-cell precursors compared to vaccination with mp53 DNA. Antibody depletion experiments also demonstrated that CD8(+ T-cells play crucial roles in the antitumor effects. This study showed intramuscular vaccination with xenogeneic p53 DNA vaccine followed by electroporation is capable of inducing potent antitumor effects against tumors

  14. AAVPG: A vigilant vector where transgene expression is induced by p53

    Using p53 to drive transgene expression from viral vectors may provide on demand expression in response to physiologic stress, such as hypoxia or DNA damage. Here we introduce AAVPG, an adeno-associated viral (AAV) vector where a p53-responsive promoter, termed PG, is used to control transgene expression. In vitro assays show that expression from the AAVPG-luc vector was induced specifically in the presence of functional p53 (1038±202 fold increase, p<0.001). The AAVPG-luc vector was an effective biosensor of p53 activation in response to hypoxia (4.48±0.6 fold increase in the presence of 250 µM CoCl2, p<0.001) and biomechanical stress (2.53±0.4 fold increase with stretching, p<0.05). In vivo, the vigilant nature of the AAVPG-luc vector was revealed after treatment of tumor-bearing mice with doxorubicin (pre-treatment, 3.4×105±0.43×105 photons/s; post-treatment, 6.6×105±2.1×105 photons/s, p<0.05). These results indicate that the AAVPG vector is an interesting option for detecting p53 activity both in vitro and in vivo. - Highlights: • AAV vector where transgene expression is controlled by the tumor suppressor p53. • The new vector, AAVPG, shown to function as a biosensor of p53 activity, in vitro and in vivo. • The p53 activity monitored by the AAVPG vector is relevant to cancer and other diseases. • AAVPG reporter gene expression was activated upon DNA damage, hypoxia and mechanical stress

  15. AAVPG: A vigilant vector where transgene expression is induced by p53

    Bajgelman, Marcio C.; Medrano, Ruan F.V.; Carvalho, Anna Carolina P.V.; Strauss, Bryan E., E-mail: bstrauss@usp.br

    2013-12-15

    Using p53 to drive transgene expression from viral vectors may provide on demand expression in response to physiologic stress, such as hypoxia or DNA damage. Here we introduce AAVPG, an adeno-associated viral (AAV) vector where a p53-responsive promoter, termed PG, is used to control transgene expression. In vitro assays show that expression from the AAVPG-luc vector was induced specifically in the presence of functional p53 (1038±202 fold increase, p<0.001). The AAVPG-luc vector was an effective biosensor of p53 activation in response to hypoxia (4.48±0.6 fold increase in the presence of 250 µM CoCl{sub 2}, p<0.001) and biomechanical stress (2.53±0.4 fold increase with stretching, p<0.05). In vivo, the vigilant nature of the AAVPG-luc vector was revealed after treatment of tumor-bearing mice with doxorubicin (pre-treatment, 3.4×10{sup 5}±0.43×10{sup 5} photons/s; post-treatment, 6.6×10{sup 5}±2.1×10{sup 5} photons/s, p<0.05). These results indicate that the AAVPG vector is an interesting option for detecting p53 activity both in vitro and in vivo. - Highlights: • AAV vector where transgene expression is controlled by the tumor suppressor p53. • The new vector, AAVPG, shown to function as a biosensor of p53 activity, in vitro and in vivo. • The p53 activity monitored by the AAVPG vector is relevant to cancer and other diseases. • AAVPG reporter gene expression was activated upon DNA damage, hypoxia and mechanical stress.

  16. Driving p53 Response to Bax Activation Greatly Enhances Sensitivity to Taxol by Inducing Massive Apoptosis

    Paola De Feudis

    2000-05-01

    Full Text Available The proapoptotic gene bax is one of the downstream effectors of p53. The p53 binding site in the bax promoter is less responsive to p53 than the one in the growth arrest mediating gene p21. We introduced the bax gene under the control of 13 copies of a strong p53 responsive element into two ovarian cancer cell lines. The clones expressing bax under the control of p53 obtained from the wild-type (wt p53-expressing cell line A2780 were much more sensitive (500- to 1000-fold to the anticancer agent taxol than the parent cell line, with a higher percentage of cells undergoing apoptosis after drug treatment that was clearly p53-dependent and bax-mediated. Xenografts established in nude mice from one selected clone (A2780/C3 were more responsive to taxol than the parental line and the apoptotic response of A2780/C3 tumors was also increased after treatment. Introduction of the same plasmid into the p53 null SKOV3 cell line did not alter the sensitivity to taxol or the induction of apoptosis. In conclusion, driving the p53 response (after taxol treatment by activating the bax gene rather than the p21 gene results in induction of massive apoptosis, in vitro and in vivo, and greatly enhances sensitivity to the drug.

  17. Gene Expression Profiling Identifies Important Genes Affected by R2 Compound Disrupting FAK and P53 Complex

    Focal Adhesion Kinase (FAK) is a non-receptor kinase that plays an important role in many cellular processes: adhesion, proliferation, invasion, angiogenesis, metastasis and survival. Recently, we have shown that Roslin 2 or R2 (1-benzyl-15,3,5,7-tetraazatricyclo[3.3.1.1~3,7~]decane) compound disrupts FAK and p53 proteins, activates p53 transcriptional activity, and blocks tumor growth. In this report we performed a microarray gene expression analysis of R2-treated HCT116 p53+/+ and p53−/− cells and detected 1484 genes that were significantly up- or down-regulated (p < 0.05) in HCT116 p53+/+ cells but not in p53−/− cells. Among up-regulated genes in HCT p53+/+ cells we detected critical p53 targets: Mdm-2, Noxa-1, and RIP1. Among down-regulated genes, Met, PLK2, KIF14, BIRC2 and other genes were identified. In addition, a combination of R2 compound with M13 compound that disrupts FAK and Mmd-2 complex or R2 and Nutlin-1 that disrupts Mdm-2 and p53 decreased clonogenicity of HCT116 p53+/+ colon cancer cells more significantly than each agent alone in a p53-dependent manner. Thus, the report detects gene expression profile in response to R2 treatment and demonstrates that the combination of drugs targeting FAK, Mdm-2, and p53 can be a novel therapy approach

  18. Analysis of p53 expression and proliferative assessment using PCNA in localized prostate carcinoma

    Leite K.R.M.

    1999-01-01

    Full Text Available The surgical specimens from 51 men submitted to radical prostatectomy for localized prostate cancer were examined by immunohistochemistry using proliferation cell nuclear antigen (PCNA monoclonal antibody to evaluate the proliferative index (PI. The relationship between PI, biological variables and p53 protein expression was evaluated by immunohistochemistry. PI was low in invasive localized prostate carcinoma (mean, 12.4% and the incidence of PCNA-positive cells was significantly higher in tumors with p53 expression (P = 0.0226. There was no statistical difference in PCNA values when biological parameters such as Gleason score, tumor volume, extraprostatic involvement, seminal vesicle infiltration or lymph node metastasis were considered. We conclude that proliferative activity is usually low in prostate carcinoma but is correlated with p53 immune staining, indicating that p53 is important in cell cycle control in this neoplasm.

  19. Dual Roles of MDM2 in the Regulation of p53: Ubiquitination Dependent and Ubiquitination Independent Mechanisms of MDM2 Repression of p53 Activity

    Shi, Dingding; Gu, Wei

    2012-01-01

    MDM2 oncogenic protein is the principal cellular antagonist of the p53 tumor suppresser gene. p53 activity needs exquisite control to elicit appropriate responses to differential cellular stress conditions. p53 becomes stabilized and active upon various types of stresses. However, too much p53 is not beneficial to cells and causes lethality. At the steady state, p53 activity needs to be leashed for cell survival. Early studies suggested that the MDM2 oncoprotein negatively regulates p53 activ...

  20. FATS is a transcriptional target of p53 and associated with antitumor activity

    Zhang Xifeng

    2010-09-01

    Full Text Available Abstract Frequent mutations of p53 in human cancers exemplify its crucial role as a tumor suppressor transcription factor, and p21, a transcriptional target of p53, plays a central role in surveillance of cell-cycle checkpoints. Our previous study has shown that FATS stabilize p21 to preserve genome integrity. In this study we identified a novel transcript variant of FATS (GenBank: GQ499374 through screening a cDNA library from mouse testis, which uncovered the promoter region of mouse FATS. Mouse FATS was highly expressed in testis. The p53-responsive elements existed in proximal region of both mouse and human FATS promoters. Functional study indicated that the transcription of FATS gene was activated by p53, whereas such effect was abolished by site-directed mutagenesis in the p53-RE of FATS promoter. Furthermore, the expression of FATS increased upon DNA damage in a p53-dependent manner. FATS expression was silent or downregulated in human cancers, and overexpression of FATS suppressed tumorigenicity in vivo independently of p53. Our results reveal FATS as a p53-regulated gene to monitor genomic stability.

  1. P53 activation, a key event of the cellular response to gamma irradiation

    The tumor suppressor gene p53 encodes a protein whose major function is to protect organisms from proliferation of potentially tumorigenic cells. In normal conditions (unstressed cells), the p53 protein is inert and maintained at low level through its association with the Mdm2 oncogene, causing its translocation from the nucleus into the cytoplasm and its degradation through ubiquitin/proteasome pathway. In response to damaged DNA or to a variety of stresses, p53 accumulates in the nucleus and is activated as a transcriptional trans-activator. Posttranslational modifications of p53 including multi-site phosphorylation and acetylation are the major mechanism of p53 regulation. After exposure to ionising radiation, p53 activation implicates ATM, ATR, Chk2 and Chk1 kinases that phosphorylate the N-terminal domain on Ser15 (ATM and/or ATR), and Ser20 (Chk2 and/or Chk1), causing the dissociation of the p53/Mdm2 complex and thereby the stabilisation of p53. The process initiated by γ-irradiation exposure involves also increased interaction of the p53 N-terminal domain with CBP/p300 and P/CAF leading to acetylation of the distant C-terminal domain at Lys 320, 373 and 382. In addition, the ATM-mediated dephosphorylation of Ser376 creates a fixation site for 14-3-3 protein. Taken together, phosphorylation, acetylation and association with co factors induce the stimulation of p53 transcriptional activity resulting in the expression of a set of genes involved, notably, in cell cycle arrest and apoptosis. This stress-induced p53 pathways lead to one of two outcomes: growth arrest or apoptosis and consequently protects the organism from the genotoxic effects of ionising radiation. (author)

  2. The CXXC finger 5 protein is required for DNA damage-induced p53 activation

    2009-01-01

    The tumor suppressor p53 is a critical component of the DNA damage response pathway that induces a set of genes responsible for cell cycle arrest,senescence,apoptosis,and DNA repair.The ataxia te-langiectasia mutated protein kinase(ATM) responds to DNA-damage stimuli and signals p53 stabiliza-tion and activation,thereby facilitating transactivation of p53 inducible genes and maintainence of genome integrity.In this study,we identified a CXXC zinc finger domain containing protein termed CF5 as a critical component in the DNA damage signaling pathway.CF5 induces p53 transcriptional activity and apoptosis in cells expressing wild type p53 but not in p53-deficient cells.Knockdown of CF5 in-hibits DNA damage-induced p53 activation as well as cell cycle arrest.Furthermore,CF5 physically interacts with ATM and is required for DNA damage-induced ATM phosphorylation but not its recruitment to chromatin.These findings suggest that CF5 plays a crucial role in ATM-p53 signaling in response to DNA damage.

  3. Genome wide expression profiling of p53 regulated miRNAs in neuroblastoma.

    Rihani, Ali; Van Goethem, Alan; Ongenaert, Maté; De Brouwer, Sara; Volders, Pieter-Jan; Agarwal, Saurabh; De Preter, Katleen; Mestdagh, Pieter; Shohet, Jason; Speleman, Frank; Vandesompele, Jo; Van Maerken, Tom

    2015-01-01

    Restoration of the antitumor activity of p53 could offer a promising approach for the treatment of neuroblastoma. MicroRNAs (miRNAs) are important mediators of p53 activity, but their role in the p53 response has not yet been comprehensively addressed in neuroblastoma. Therefore, we set out to characterize alterations in miRNA expression that are induced by p53 activation in neuroblastoma cells. Genome-wide miRNA expression analysis showed that miR-34a-5p, miR-182-5p, miR-203a, miR-222-3p, and miR-432-5p are upregulated following nutlin-3 treatment in a p53 dependent manner. The function of miR-182-5p, miR-203a, miR-222-3p, and miR-432-5p was analyzed by ectopic overexpression of miRNA mimics. We observed that these p53-regulated miRNAs inhibit the proliferation of neuroblastoma cells to varying degrees, with the most profound growth inhibition recorded for miR-182-5p. Overexpression of miR-182-5p promoted apoptosis in some neuroblastoma cell lines and induced neuronal differentiation of NGP cells. Using Chromatin Immunoprecipitation-qPCR (ChIP-qPCR), we did not observe direct binding of p53 to MIR182, MIR203, MIR222, and MIR432 in neuroblastoma cells. Taken together, our findings yield new insights in the network of p53-regulated miRNAs in neuroblastoma. PMID:25762502

  4. Activation of p53 with Ilimaquinone and Ethylsmenoquinone, Marine Sponge Metabolites, Induces Apoptosis and Autophagy in Colon Cancer Cells

    Hyun-Young Lee; Kyu Jin Chung; In Hyun Hwang; Jungsuk Gwak; Seoyoung Park; Bong Gun Ju; Eunju Yun; Dong-Eun Kim; Young-Hwa Chung; MinKyun Na; Gyu-Yong Song; Sangtaek Oh

    2015-01-01

    The tumor suppressor, p53, plays an essential role in the cellular response to stress through regulating the expression of genes involved in cell cycle arrest, apoptosis and autophagy. Here, we used a cell-based reporter system for the detection of p53 response transcription to identify the marine sponge metabolites, ilimaquinone and ethylsmenoquinone, as activators of the p53 pathway. We demonstrated that ilimaquinone and ethylsmenoquinone efficiently stabilize the p53 protein through promot...

  5. Effect of p53 genotype on gene expression profiles in murine liver

    The tumor suppressor protein p53 is a key regulatory element in the cell and is regarded as the 'guardian of the genome'. Much of the present knowledge of p53 function has come from studies of transgenic mice in which the p53 gene has undergone a targeted deletion. In order to provide additional insight into the impact on the cellular regulatory networks associated with the loss of this gene, microarray technology was utilized to assess gene expression in tissues from both the p53-/- and p53+/- mice. Six male mice from each genotype (p53+/+, p53+/-, and p53-/-) were humanely killed and the tissues processed for microarray analysis. The initial studies have been performed in the liver for which the Dunnett test revealed 1406 genes to be differentially expressed between p53+/+ and p53+/- or between p53+/+ and p53-/- at the level of p ≤ 0.05. Both genes with increased expression and decreased expression were identified in p53+/- and in p53-/- mice. Most notable in the gene list derived from the p53+/- mice was the significant reduction in p53 mRNA. In the p53-/- mice, not only was there reduced expression of the p53 genes on the array, but genes associated with DNA repair, apoptosis, and cell proliferation were differentially expressed, as expected. However, altered expression was noted for many genes in the Cdc42-GTPase pathways that influence cell proliferation. This may indicate that alternate pathways are brought into play in the unperturbed liver when loss or reduction in p53 levels occurs

  6. Mutant p53: Multiple Mechanisms Define Biologic Activity in Cancer

    Kim, Michael Paul; Zhang, Yun; Lozano, Guillermina

    2015-01-01

    The functional importance of p53 as a tumor suppressor gene is evident through its pervasiveness in cancer biology. The p53 gene is the most commonly altered gene in human cancer; however, not all genetic alterations are biologically equivalent. The majority of alterations involve p53 missense mutations that result in the production of mutant p53 proteins. Such mutant p53 proteins lack normal p53 function and may concomitantly gain novel functions, often with deleterious effects. Here, we rev...

  7. p53 increases MHC class I expression by upregulating the endoplasmic reticulum aminopeptidase ERAP1

    Wang, Bei; Niu, Dandan; Lai, Liyun; Ren, Ee Chee

    2013-01-01

    The p53 tumour suppressor has an important role in cancer cells. Here we show that p53 regulates expression of major histocompatibility complex I on the cell surface. We show that the tumour cell line HCT116, which lacks p53 exhibits significantly lower major histocompatibility complex I expression than its wild-type counterpart. Using a combination of chromatin immunoprecipitation sequencing and gene expression analysis, we demonstrate that p53 upregulates expression of endoplasmic reticulum...

  8. Molecular mechanisms of growth suppression by pharmacologically activated p53

    Hedström, Elisabeth

    2009-01-01

    The tumor suppressor p53 is a transcription factor that is crucial for protecting cells from cancer development. The importance of p53 tumor suppression function is highlighted by the fact that the p53 pathway is inactivated in most, if not all cancers. Mutation of the p53 gene occurs in about 50% of all tumors, whereas in the tumors which retain wild-type p53, the function of p53 is abolished due to deregulation of the p53 pathway. Due to the potency of p53 in suppressing t...

  9. Pla2g16 phospholipase mediates gain-of-function activities of mutant p53.

    Xiong, Shunbin; Tu, Huolin; Kollareddy, Madhusudhan; Pant, Vinod; Li, Qin; Zhang, Yun; Jackson, James G; Suh, Young-Ah; Elizondo-Fraire, Ana C; Yang, Peirong; Chau, Gilda; Tashakori, Mehrnoosh; Wasylishen, Amanda R; Ju, Zhenlin; Solomon, Hilla; Rotter, Varda; Liu, Bin; El-Naggar, Adel K; Donehower, Lawrence A; Martinez, Luis Alfonso; Lozano, Guillermina

    2014-07-29

    p53(R172H/+) mice inherit a p53 mutation found in Li-Fraumeni syndrome and develop metastatic tumors at much higher frequency than p53(+/-) mice. To explore the mutant p53 metastatic phenotype, we used expression arrays to compare primary osteosarcomas from p53(R172H/+) mice with metastasis to osteosarcomas from p53(+/-) mice lacking metastasis. For this study, 213 genes were differentially expressed with a P value ETS2 suppressed mutant p53 induction of Pla2g16. Thus, our study identifies a phospholipase as a transcriptional target of mutant p53 that is required for metastasis. PMID:25024203

  10. Insights into p53 transcriptional function via genome-wide chromatin occupancy and gene expression analysis

    F Nikulenkov; Spinnler, C; Li, H.; Tonelli, C; Shi, Y; Turunen, M.; Kivioja, T; Ignatiev, I.; Kel, A; Taipale, J; Selivanova, G

    2012-01-01

    The tumor-suppressor p53 can induce various biological responses. Yet, it is not clear whether it is p53 in vivo promoter selectivity that triggers different transcription programs leading to different outcomes. Our analysis of genome-wide chromatin occupancy by p53 using chromatin immunoprecipitation (ChIP)-seq revealed ‘p53 default program', that is, the pattern of major p53-bound sites that is similar upon p53 activation by nutlin3a, reactivation of p53 and induction of tumor cell apoptosi...

  11. Modulation of p53β and p53γ expression by regulating the alternative splicing of TP53 gene modifies cellular response

    Marcel, V; Fernandes, K; Terrier, O; LANE, D. P.; Bourdon, J-C

    2014-01-01

    In addition to the tumor suppressor p53 protein, also termed p53α, the TP53 gene produces p53β and p53γ through alternative splicing of exons 9β and 9γ located within TP53 intron 9. Here we report that both TG003, a specific inhibitor of Cdc2-like kinases (Clk) that regulates the alternative splicing pre-mRNA pathway, and knockdown of SFRS1 increase expression of endogenous p53β and p53γ at mRNA and protein levels. Development of a TP53 intron 9 minigene shows that TG003 treatment and knockdo...

  12. Transcriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB

    Benoit, Valérie; Moraes, E.; Dar, N A; Taranchon, E.; Bours, Vincent; Hautefeuille, A.; Taniere, P; Chariot, Alain; Scoazec, J Y; Gallo, C. V. D.; Merville, Marie-Paule; Hainaut, Pierre

    2006-01-01

    Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by inducing the binding of nuclear factor-kappaB (NF-kappaB) to its response element in the COX-2 promoter. Inhibition of NF-kappaB prevented p53 induction of Cox-2 expression. Cooperation between p53 and NF-kappaB was required for activation of COX-2 promoter in response to daunomycin, a DNA-dama...

  13. Methylation of WTH3, a possible drug resistant gene, inhibits p53 regulated expression

    Previous results showed that over-expression of the WTH3 gene in MDR cells reduced MDR1 gene expression and converted their resistance to sensitivity to various anticancer drugs. In addition, the WTH3 gene promoter was hypermethylated in the MCF7/AdrR cell line and primary drug resistant breast cancer epithelial cells. WTH3 was also found to be directly targeted and up regulated by the p53 gene. Furthermore, over expression of the WTH3 gene promoted the apoptotic phenotype in various host cells. To further confirm WTH3's drug resistant related characteristics, we recently employed the small hairpin RNA (shRNA) strategy to knockdown its expression in HEK293 cells. In addition, since the WTH3 promoter's p53-binding site was located in a CpG island that was targeted by methylation, we were interested in testing the possible effect this epigenetic modification had on the p53 transcription factor relative to WTH3 expression. To do so, the in vitro methylation method was utilized to examine the p53 transgene's influence on either the methylated or non-methylated WTH3 promoter. The results generated from the gene knockdown strategy showed that reduction of WTH3 expression increased MDR1 expression and elevated resistance to Doxorubicin as compared to the original control cells. Data produced from the methylation studies demonstrated that DNA methylation adversely affected the positive impact of p53 on WTH3 promoter activity. Taken together, our studies provided further evidence that WTH3 played an important role in MDR development and revealed one of its transcription regulatory mechanisms, DNA methylation, which antagonized p53's positive impact on WTH3 expression

  14. Expression of p53 and CD44 in Canine Breast Tumor

    LIU Yun; CUI Wen; CHENG Xi; FENG Xinchang

    2008-01-01

    The p53 and CD44 expression of 10 cases in canine breast tumor were examined utilizing immunohistochemical assay with rabbit anti-mouse polyclonal antibodies against p53 or CD44,respectively.The p53 expression was significantly higher in malignant than in benign breast tumor.The expression of CD44 was not significantly different in malignant breast cancer and benign breast tumor.This suggests that p53 can be used as an indicator for animal prognosis.

  15. Restoration of p53 Expression in Human Cancer Cell Lines Upregulates the Expression of Notch1: Implications for Cancer Cell Fate Determination after Genotoxic Stress

    Fatouma Alimirah

    2007-05-01

    Full Text Available Following genotoxic stress, transcriptional activation of target genes by p53 tumor suppressor is critical in cell fate determination. Here we report that the restoration of p53 function in human cancer cell lines that are deficient in p53 function upregulated the expression of Notch1. Interestingly, the expression of wild-type p53 in human prostate and breast cancer cell lines correlated well with increased expression of Notch1. Furthermore, knockdown of p53 expression in cancer cells that express wild-type p53 resulted in reduced expression of Notch1. Importantly, genotoxic stress to cancer cells that resulted in activation of p53 also upregulated the expression of Notch1. Moreover, p53mediated induction of Notch1 expression was associated with stimulation of the activity of Notch-responsive reporters. Notably, p53 differentially regulated the expression of Notch family members: expression of Notch2 and Notch4 was not induced by p53. Significantly, treatment of cells with gamma secretase inhibitor, an inhibitor of Notch signaling, increased susceptibility to apoptosis in response to genotoxic stress. Together, our observations suggest that p53mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress.

  16. Prima-1 induces apoptosis in bladder cancer cell lines by activating p53

    Camila B. Piantino

    2013-01-01

    Full Text Available OBJECTIVES: Bladder cancer represents 3% of all carcinomas in the Brazilian population and ranks second in incidence among urological tumors, after prostate cancer. The loss of p53 function is the main genetic alteration related to the development of high-grade muscle-invasive disease. Prima-1 is a small molecule that restores tumor suppressor function to mutant p53 and induces cancer cell death in various cancer types. Our aim was to investigate the ability of Prima-1 to induce apoptosis after DNA damage in bladder cancer cell lines. METHOD: The therapeutic effect of Prima-1 was studied in two bladder cancer cell lines: T24, which is characterized by a p53 mutation, and RT4, which is the wild-type for the p53 gene. Morphological features of apoptosis induced by p53, including mitochondrial membrane potential changes and the expression of thirteen genes involved in apoptosis, were assessed by microscopic observation and quantitative real-time PCR (qRT-PCR. RESULTS: Prima-1 was able to reactivate p53 function in the T24 (p53 mt bladder cancer cell line and promote apoptosis via the induction of Bax and Puma expression, activation of the caspase cascade and disruption of the mitochondrial membrane in a BAK-independent manner. CONCLUSION: Prima-1 is able to restore the transcriptional activity of p53. Experimental studies in vivo may be conducted to test this molecule as a new therapeutic agent for urothelial carcinomas of the bladder, which characteristically harbor p53 mutations.

  17. p53-independent activation of the hdm2-P2 promoter through multiple transcription factor response elements results in elevated hdm2 expression in estrogen receptor alpha-positive breast cancer cells.

    Phelps, Monika; Darley, Matthew; Primrose, John N; Blaydes, Jeremy P

    2003-05-15

    The negative-regulatory feedback loop between p53 and hdm2 forms part of a finely balanced regulatory network of proteins that controls cell cycle progression and commitment to apoptosis. Expression of hdm2, and its mouse orthologue mdm2, is known to be induced by p53, but recent evidence has demonstrated mdm2 expression can also be regulated via p53-independent pathways. However the p53 independent mechanisms that control transcription of the human hdm2 gene have not been studied. Differential levels of hdm2 mRNA and protein expression have been reported in several types of human malignancy, including breast cancers in which hdm2 expression correlates with positive estrogen receptor alpha (ERalpha) status. Experimental models have demonstrated that hdm2 overexpression can promote breast cancer development. Here, we show that the elevated level of hdm2 protein in ERalpha(+ve) breast cancer cell lines such as MCF-7 and T47D is because of transcription from the p53-inducible P2 promoter of hdm2. The P2 promoter is inactive in ERalpha(-ve) cell lines such as SKBr3. Hdm2-P2 promoter activity in T47D cells is independent of p53, as well as of known regulators of the mouse mdm2-P2 promoter, including ERalpha and ras-raf-mitogen-activated protein/extracellular signal-regulated kinase (MEK) mitogen-activated protein kinase (MAPK) signaling. We show that hdm2-P2 activity in T47D cells is dependent on the integrity of both an evolutionarily conserved composite binding site for AP1 and ETS family transcription factors (AP1-ETS) and a nonconserved upstream (nnGGGGC)(5) repeat sequence. Lack of hdm2-P2 activity in ERalpha(-ve) cells is shown to be a consequence of reduced transcriptional activation through the AP1-ETS element. Overexpression of ETS2 in SKBr3 cells reconstitutes AP1-ETS element-dependent hdm2-P2 promoter activity, resulting in increased levels of hdm2 protein in the cells. Our findings support the hypothesis that the elevated levels of hdm2 expression reported

  18. Wild-type and mutant p53 mediate cisplatin resistance through interaction and inhibition of active caspase-9.

    Chee, Jacqueline L Y; Saidin, Suzan; Lane, David P; Leong, Sai Mun; Noll, Jacqueline E; Neilsen, Paul M; Phua, Yi Ting; Gabra, Hani; Lim, Tit Meng

    2013-01-15

    The p53 gene has been implicated in many cancers due to its frequent mutations as well as mutations in other genes whose proteins directly affect p53's functions. In addition, high expression of p53 [wild-type (WT) or mutant] has been found in the cytoplasm of many tumor cells, and studies have associated these observations with more aggressive tumors and poor prognosis. Cytoplasmic mis-localization of p53 subsequently reduced its transcriptional activity and this loss-of-function (LOF) was used to explain the lack of response to chemotherapeutic agents. However, this hypothesis seemed inadequate in explaining the apparent selection for tumor cells with high levels of p53 protein, a phenomenon that suggests a gain-of-function (GOF) of these mis-localized p53 proteins. In this study, we explored whether the direct involvement of p53 in the apoptotic response is via regulation of the caspase pathway in the cytoplasm. We demonstrate that p53, when present at high levels in the cytoplasm, has an inhibitory effect on caspase-9. Concurrently, knockdown of endogenous p53 caused an increase in the activity of caspase-9. p53 was found to interact with the p35 fragment of caspase-9, and this interaction inhibits the caspase-9 activity. In a p53-null background, the high-level expression of both exogenous WT and mutant p53 increased the resistance of these cells to cisplatin, and the data showed a correlation between high p53 expression and caspase-9 inhibition. These results suggest the inhibition of caspase-9 as a potential mechanism in evading apoptosis in tumors with high-level p53 expression that is cytoplasmically localized. PMID:23255126

  19. P-Glycoprotein/MDR1 regulates pokemon gene transcription through p53 expression in human breast cancer cells.

    He, Shengnan; Liu, Feng; Xie, Zhenhua; Zu, Xuyu; Xu, Wei; Jiang, Yuyang

    2010-01-01

    P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of p53 as seen by use of p53 siRNA transfected MCF-7 cells or p53 mutated MDA-MB-231 cells. Moreover, p53 was detected to bind with Pgp in vivo using immunoprecipitation assay. Taken together, we conclude that Pgp can regulate the expression of pokemon through the presence of p53, suggesting that Pgp is a potent regulator and may offer an effective novel target for cancer therapy. PMID:20957096

  20. P-Glycoprotein/MDR1 Regulates Pokemon Gene Transcription Through p53 Expression in Human Breast Cancer Cells

    Wei Xu

    2010-08-01

    Full Text Available P-glycoprotein (Pgp, encoded by the multidrug resistance 1 (MDR1 gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of p53 as seen by use of p53 siRNA transfected MCF-7 cells or p53 mutated MDA-MB-231 cells. Moreover, p53 was detected to bind with Pgp in vivo using immunoprecipitation assay. Taken together, we conclude that Pgp can regulate the expression of pokemon through the presence of p53, suggesting that Pgp is a potent regulator and may offer an effective novel target for cancer therapy.

  1. In vitro and in vivo cytotoxic effects of PRIMA-1 on hepatocellular carcinoma cells expressing mutant p53ser249.

    Shi, Hong; Lambert, Jeremy M R; Hautefeuille, Agnes; Bykov, Vladimir J N; Wiman, Klas G; Hainaut, Pierre; Caron de Fromentel, Claude

    2008-07-01

    Hepatocellular carcinoma (HCC) is highly lethal due to limited curative options. In high-incidence regions, such as parts of Africa and Southeastern Asia, >50% of cases carry an AGG to AGT mutation at codon 249 of the TP53 gene, considered as a 'signature' of mutagenesis by aflatoxins. The protein product, p53ser249, may represent a therapeutic target for HCC. The small molecule p53 reactivation and induction of massive apoptosis (PRIMA)-1 has been shown to induce apoptosis in tumour cells by reactivating the transactivation capacity of some p53 mutants. In this study, we have investigated the cytotoxic effects of PRIMA-1 on HCC cells expressing p53ser249. In p53-null Hep3B cells, over-expression of p53ser249 or p53gln248 by stable transfection increased the cytotoxicity of PRIMA-1 at 50 muM. Furthermore, PRIMA-1 treatment delayed the growth of p53ser249-expressing Hep3B cells xenografted in severe combined immunodeficiency mice. However, PRIMA-1 did not restore wild-type DNA binding and transactivation activities to p53ser249 or to p53gln248 in Hep3B cells. Moreover, in PLC/PRF/5, a HCC cell line constitutively expressing p53ser249, small interfering RNA (siRNA) silencing of the mutant increased the cytotoxic effect of PRIMA-1. These apparently contradictory effects can be reconciled by proposing that p53ser249 exerts a gain-of-function effect, which favours the survival of HCC cells. Thus, both inhibition of this effect by PRIMA-1 and removal of the mutant by siRNA can lead to the decrease of survival capacity of HCC cells. PMID:18048389

  2. p53 expression in biopsies from children with Langerhans cell histiocytosis

    Bank, Micha I; Lundegaard, Pia Rengtved; Carstensen, Henrik;

    2002-01-01

    single-system lesions only without relapse, whereas others develop fatal multiorgan disease. The expression of p53 tumor suppressor gene product detected immunohistochemically can be used as a guideline to alterations in DNA repair control and apoptosis. The authors have chosen to analyze p53 expression...... diagnosis of LCH based on CD1a positivity. The slides were stained with p53 antibody and semiquantitatively evaluated using a grading system from 1 to 5 as an estimate for 0% to 20%, 20% to 40%, 40% to 60%, 60% to 80%, and 80% to 100% p53-positive for pathologic Langerhans cells (pLC), respectively. RESULTS......: The p53 protein was expressed in various degrees in pLC in all lesions. The degree of p53 expression could not be correlated to either clinical manifestation or outcome. CONCLUSIONS: An increased expression of p53 in pLC indicates an altered DNA repair control with or without abnormal control of...

  3. Clinical Significance of Mutant P53 Protein Expression in Lung Adenocarcinoma

    Chun’an BIAN; Li, Zhongyou; Youtao XU; Wang, Jie; Xu, Lin; Shen, Hongbing

    2015-01-01

    Background and objective P53 is a tumor protein that acts as a tumor suppressor. The mutation of P53 may cause loss of tumor suppressor functions and gain of functions favoring cellular proliferation and apoptosis inhibition. The clinical implications of the tumor protein P53 gene (TP53) mutation in lung adenocarcinoma are indefinite. The aim of this study is to explore the clinical significance of the mutant P53 protein expression in lung adenocarcinoma tissues. Methods The clinicopathologic...

  4. Regulation of p53 Localization and Activity by Ubc13▿ †

    Laine, Aaron; Topisirovic, Ivan; Zhai, Dayong; John C Reed; Borden, Katherine L. B.; Ronai, Ze'ev

    2006-01-01

    The abundance and activity of p53 are regulated largely by ubiquitin ligases. Here we demonstrate a previously undisclosed regulation of p53 localization and activity by Ubc13, an E2 ubiquitin-conjugating enzyme. While increasing p53 stability, Ubc13 decreases p53 transcriptional activity and increases its localization to the cytoplasm, changes that require its ubiquitin-conjugating activity. Ubc13 elicits K63-dependent ubiquitination of p53, which attenuates Hdm2-induced polyubiquitination o...

  5. CP-31398, a putative p53-stabilizing molecule tested in mammalian cells and in yeast for its effects on p53 transcriptional activity

    Barberis Alcide

    2004-11-01

    Full Text Available Abstract Background CP-31398 is a small molecule that has been reported to stabilize the DNA-binding core domain of the human tumor suppressor protein p53 in vitro. The compound was also reported to function as a potential anti-cancer drug by rescuing the DNA-binding activity and, consequently, the transcription activation function of mutant p53 protein in mammalian tissue culture cells and in mice. Results We performed a series of gene expression experiments to test the activity of CP-31398 in yeast and in human cell cultures. With these cell-based assays, we were unable to detect any specific stimulation of mutant p53 activity by this compound. Concentrations of CP-31398 that were reported to be active in the published work were highly toxic to the human H1299 lung carcinoma and Saos-2 cell lines in our experiments. Conclusion In our experiments, the small molecule CP-31398 was unable to reactivate mutant p53 protein. The results of our in vivo experiments are in agreement with the recently published biochemical analysis of CP-31398 showing that this molecule does not bind p53 as previously claimed, but intercalates into DNA.

  6. Retardation of cell growth by avian reovirus p17 through the activation of p53 pathway

    The second open reading frame of avian reovirus S1 gene segment encodes a 17 kDa non-structural protein, named p17. The biological role of p17 is fully unknown so far. Using trypan blue dye exclusion and MTT assay, we demonstrated that the ectopic expression of p17 results in the reduction of viable cell number and cell proliferation rate of Vero, BHK, 293, and HeLa cells. Measurement of LDH activity and DNA fragmentation analysis revealed that p17 expression did not cause cell death or apoptosis. These data indicated that the p17 possessed the growth retardation function. Semi-quantitative RT-PCR and Western blotting revealed that p17-expressing cells induced the expression of CDK inhibitor p21cip1/waf1 in a time- and dose-dependent manner, but the transcripts of CDK inhibitor p15INK4b, p16INK4a, or p27kip were not altered. In the presence of p17, the p53 protein level and p53-driven reporter activity were elevated significantly. Dominant negative p53 alleviated the p21 accumulation, p53 activation, and growth inhibition effect induced by p17. Taken together, these studies revealed a possible intrinsic function of p17 in growth regulation through the activation of p53 and p21cip1/waf1

  7. Association of p53 protein expression with clinical outcome in advanced supraglottic cancer

    To determine the incidence and prognostic effect of p53 expression in patients with advanced supraglottic cancer. Twenty-one cases of total 48 advanced supraglottic cancer patients who received postoperative adjuvant radiation therapy were evaluated by immunohistochemical staining employing p53 monoclonal antibody. Three out of six stage III patients and four out of fifteen stage IV patients showed p53 expression without statistically significant difference (p=0.608). Five year survival rates are 93% in p53 negative, 86% in p53 positive patients and there was no significant difference(p=0.776). p53 expression does not show statistically significant correlation with primary tumor status(p=0.877), lymph node status(p=0.874) and age(p=0.64). There was no statistically significant correlation between traditionally known risk factors and p53 expression

  8. Cancer cell sensitivity to bortezomib is associated with survivin expression and p53 status but not cancer cell types

    Chanan-Khan Asher A

    2010-01-01

    Full Text Available Abstract Background Survivin is known playing a role in drug resistance. However, its role in bortezomib-mediated inhibition of growth and induction of apoptosis is unclear. There are conflicting reports for the effect of bortezomib on survivin expression, which lacks of a plausible explanation. Methods: In this study, we tested cancer cells with both p53 wild type and mutant/null background for the relationship of bortezomib resistance with survivin expression and p53 status using MTT assay, flow cytometry, DNA fragmentation, caspase activation, western blots and RNAi technology. Results We found that cancer cells with wild type p53 show a low level expression of survivin and are sensitive to treatment with bortezomib, while cancer cells with a mutant or null p53 show a high level expression of survivin and are resistant to bortezomib-mediated apoptosis induction. However, silencing of survivin expression utilizing survivin mRNA-specific siRNA/shRNA in p53 mutant or null cells sensitized cancer cells to bortezomib mediated apoptosis induction, suggesting a role for survivin in bortezomib resistance. We further noted that modulation of survivin expression by bortezomib is dependent on p53 status but independent of cancer cell types. In cancer cells with mutated p53 or p53 null, bortezomib appears to induce survivin expression, while in cancer cells with wild type p53, bortezomib downregulates or shows no significant effect on survivin expression, which is dependent on the drug concentration, cell line and exposure time. Conclusions Our findings, for the first time, unify the current inconsistent findings for bortezomib treatment and survivin expression, and linked the effect of bortezomib on survivin expression, apoptosis induction and bortezomib resistance in the relationship with p53 status, which is independent of cancer cell types. Further mechanistic studies along with this line may impact the optimal clinical application of bortezomib in

  9. Gene Expression Profiling Identifies Important Genes Affected by R2 Compound Disrupting FAK and P53 Complex

    Golubovskaya, Vita M., E-mail: Vita.Golubovskaya@roswellpark.org; Ho, Baotran [Department of Surgical Oncology, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Conroy, Jeffrey [Genomics Shared Resource, Center for Personalized Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Liu, Song; Wang, Dan [Bioinformatics Core Facility, Biostatistics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Cance, William G. [Department of Surgical Oncology, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States)

    2014-01-21

    Focal Adhesion Kinase (FAK) is a non-receptor kinase that plays an important role in many cellular processes: adhesion, proliferation, invasion, angiogenesis, metastasis and survival. Recently, we have shown that Roslin 2 or R2 (1-benzyl-15,3,5,7-tetraazatricyclo[3.3.1.1~3,7~]decane) compound disrupts FAK and p53 proteins, activates p53 transcriptional activity, and blocks tumor growth. In this report we performed a microarray gene expression analysis of R2-treated HCT116 p53{sup +/+} and p53{sup −/−} cells and detected 1484 genes that were significantly up- or down-regulated (p < 0.05) in HCT116 p53{sup +/+} cells but not in p53{sup −/−} cells. Among up-regulated genes in HCT p53{sup +/+} cells we detected critical p53 targets: Mdm-2, Noxa-1, and RIP1. Among down-regulated genes, Met, PLK2, KIF14, BIRC2 and other genes were identified. In addition, a combination of R2 compound with M13 compound that disrupts FAK and Mmd-2 complex or R2 and Nutlin-1 that disrupts Mdm-2 and p53 decreased clonogenicity of HCT116 p53{sup +/+} colon cancer cells more significantly than each agent alone in a p53-dependent manner. Thus, the report detects gene expression profile in response to R2 treatment and demonstrates that the combination of drugs targeting FAK, Mdm-2, and p53 can be a novel therapy approach.

  10. Teroxirone inhibited growth of human non-small cell lung cancer cells by activating p53

    In this work, we demonstrated that the growth of human non-small-cell-lung-cancer cells H460 and A549 cells can be inhibited by low concentrations of an epoxide derivative, teroxirone, in both in vitro and in vivo models. The cytotoxicity was mediated by apoptotic cell death through DNA damage. The onset of ultimate apoptosis is dependent on the status of p53. Teroxirone caused transient elevation of p53 that activates downstream p21 and procaspase-3 cleavage. The presence of caspase-3 inhibitor reverted apoptotic phenotype. Furthermore, we showed the cytotoxicity of teroxirone in H1299 cells with stable ectopic expression of p53, but not those of mutant p53. A siRNA-mediated knockdown of p53 expression attenuated drug sensitivity. The in vivo experiments demonstrated that teroxirone suppressed growth of xenograft tumors in nude mice. Being a potential therapeutic agent by restraining cell growth through apoptotic death at low concentrations, teroxirone provides a feasible perspective in reversing tumorigenic phenotype of human lung cancer cells. - Highlights: • Teroxirone repressed tumor cell growth in nude mice of human lung cancer cells. • The apoptotic cell death reverted by caspase-3 inhibitor is related to p53 status. • Teroxirone provides a good candidate for lung cancer treatment

  11. Teroxirone inhibited growth of human non-small cell lung cancer cells by activating p53

    Wang, Jing-Ping; Lin, Kai-Han; Liu, Chun-Yen; Yu, Ya-Chu; Wu, Pei-Tsun [Department of Life Science, National Taiwan Normal University, Taipei, Taiwan (China); Chiu, Chien-Chih [Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Su, Chun-Li [Department of Human Development and Family Studies, National Taiwan Normal University, Taipei, Taiwan (China); Chen, Kwun-Min [Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan (China); Fang, Kang, E-mail: kangfang@ntnu.edu.tw [Department of Life Science, National Taiwan Normal University, Taipei, Taiwan (China)

    2013-11-15

    In this work, we demonstrated that the growth of human non-small-cell-lung-cancer cells H460 and A549 cells can be inhibited by low concentrations of an epoxide derivative, teroxirone, in both in vitro and in vivo models. The cytotoxicity was mediated by apoptotic cell death through DNA damage. The onset of ultimate apoptosis is dependent on the status of p53. Teroxirone caused transient elevation of p53 that activates downstream p21 and procaspase-3 cleavage. The presence of caspase-3 inhibitor reverted apoptotic phenotype. Furthermore, we showed the cytotoxicity of teroxirone in H1299 cells with stable ectopic expression of p53, but not those of mutant p53. A siRNA-mediated knockdown of p53 expression attenuated drug sensitivity. The in vivo experiments demonstrated that teroxirone suppressed growth of xenograft tumors in nude mice. Being a potential therapeutic agent by restraining cell growth through apoptotic death at low concentrations, teroxirone provides a feasible perspective in reversing tumorigenic phenotype of human lung cancer cells. - Highlights: • Teroxirone repressed tumor cell growth in nude mice of human lung cancer cells. • The apoptotic cell death reverted by caspase-3 inhibitor is related to p53 status. • Teroxirone provides a good candidate for lung cancer treatment.

  12. P53 and Beta-Catenin Activity during Estrogen treatment of Osteoblasts

    Kolman Kevin

    2005-07-01

    Full Text Available Abstract Background This study was undertaken to examine the relationship between the tumor suppressor gene p53 and the nuclear signaling protein beta-catenin during bone differentiation. Cross talk between p53 and beta-catenin pathways has been demonstrated and is important during tumorigenesis and DNA damage, where deregulation of beta catenin activates p53. In this study, we used estrogen treatment of osteoblasts as a paradigm to study the relationship between the two proteins during osteoblast differentiation. Results We exposed osteoblast-like ROS17/2.8 cells to 17-beta estradiol (E2, in a short term assay, and studied the cellular distribution and expression of beta-catenin. We found beta-catenin to be up regulated several fold following E2 treatment. Levels of p53 and its functional activity mirrored the quantitative changes seen in beta-catenin. Alkaline phosphatase, an early marker of osteoblast differentiation, was increased in a manner similar to beta-catenin and p53. In order to determine if there was a direct relationship between alkaline phosphatase expression and beta-catenin, we used two different approaches. In the first approach, treatment with LiCl, which is known to activate beta-catenin, caused a several fold increase in alkaline phosphatase activity. In the second approach, transient transfection of wild type beta-catenin into osteoblasts increased alkaline phosphatase activity two fold over basal levels, showing that beta catenin expression can directly affect alkaline phosphatase expression. However increase in beta catenin activity was not associated with an increase in its signaling activity through TCF/LEF mediated transcription. Immunofluorescence analyses of p53 and beta-catenin localization showed that E2 first caused an increase in cytosolic beta-catenin followed by the accumulation of beta-catenin in the nucleus. Nuclear p53 localization was detected in several cells. Expression of p53 was accompanied by

  13. GFP tracking transcriptional activity endogenous p53: vector construction and application in genotoxicity detection

    ZENG Wei-sen; LUO Chen; XIE Wei-bing; CHEN Han-yuan

    2001-01-01

    To establish a sensitive.and specific system for genotoxicity detection in vivo. Methods: Endogenous p53 tracer vector p53RE was constructed by using green fluorescent protein (GFP) as a reporter to trace p53 transcriptional activity under the control of base SV40 early promoter. The tracer cells 3T3-REG were established by transfecting NIH3T3 cells with tracer vector and treated with ultraviolet, H202 and adriamycin to induce DNA damage and the subsequent endogenous p53 expression. The GFP expression and its green fluorescence in the tracer cells were observed and measured with fluorescent microscope and FACS. Results: The GFP expression increased rapidly after various treatment and reached the maximum 1 h later, and decreased gradually afterwards. FACS analysis showed that GFP expression in 3T3-REG tracer cells was consistent with the concentration of H202, while that in 3T3-SVG cells, which were transfected with control vector pSV-GFP, hardly increased in response to the treatment. Conclusion: GFP tracing p53 transcriptional activity is a sensitive and specific method for genotoxicity detection.

  14. Transcriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB.

    Benoit, V; de Moraes, E; Dar, N A; Taranchon, E; Bours, V; Hautefeuille, A; Tanière, P; Chariot, A; Scoazec, J-Y; de Moura Gallo, C V; Merville, M-P; Hainaut, P

    2006-09-21

    Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by inducing the binding of nuclear factor-kappaB (NF-kappaB) to its response element in the COX-2 promoter. Inhibition of NF-kappaB prevented p53 induction of Cox-2 expression. Cooperation between p53 and NF-kappaB was required for activation of COX-2 promoter in response to daunomycin, a DNA-damaging agent. Pharmacological inhibition of Cox-2 enhanced apoptosis in response to daunomycin, in particular in cells containing active p53. In esophageal cancer, there was a correlation between Cox-2 expression and wild-type TP53 in Barrett's esophagus (BE) and in adenocarcinoma, but not in squamous cell carcinoma (P<0.01). These results suggest that p53 and NF-kappaB cooperate in upregulating Cox-2 expression, promoting cell survival in inflammatory precursor lesions such as BE. PMID:16682957

  15. The role of p53 in radiation activated recombination in human teratocarcinoma cells

    Purpose/Objective: We have previously demonstrated that ionizing radiation can activate a DNA recombination pathway in mammalian cells. In this project, we investigated the role of p53 in radiation activated recombination in ovarian tumor cell lines, and also the effect of p53 status on radiation sensitivity in this cell system. Materials and Methods: PA-1 teratocarcinoma cells, which express wild type p53, were transfected with an HPV16 E6 expression vector (PA-1/E6) which promotes p53 degradation, or transfected with a similar vector coding only for the neomycin phosphotransferase gene (PA-1/Neo). Approximately 3 weeks after this transfection, surviving cells were pooled and expanded. Nuclear extracts were made from each cell line three hours after cells were irradiated with doses ranging from 0 Gy to 10 Gy. Briefly, cells were lysed in sucrose buffer, and the nuclei and cytoplasm separated by centrifugation. Nuclei were lysed in low salt buffer followed by high salt buffer and centrifugation (as described by Johnson et al., Biotechniques 19:193-5, 1995). The ability of these nuclear extracts to rejoin or recombine EcoRI linearized pSV2neo was then determined. The effect of irradiation and P53 on stable transfection determined by assessing transfection of a Hygromycin marker vector (pSV2HPH). Radiation sensitivity was also determined. Results: Nuclear extracts from unirradiated cells had demonstrated end joining activity. PA-1/Neo had little end joining activity as measured by dimerization of linearized pSV2neo. Recutting of these dimers with EcoRI almost completely removed the dimer. PA-1/E6 demonstrated significantly more dimer formation (∼10 fold more) than PA-1/Neo. These dimers could only be reduced to ∼50% of PA-1/E6 control by redigestion with EcoRI. Nuclear extracts generated 3 hours after irradiation also had end joining activity. After 10Gy, PA-1/Neo demonstrated markedly elevated end joining activity to the level seen in unirradiated PA-1/E6. This

  16. Expression and significance of VEGF and p53 in degenerate intervertebral disc tissue

    Xiao-Yu Lu; Xiao-Hong Ding; Li-Jun Zhong; Hong Xia; Xiao-Dong Chen; Hai Huang

    2013-01-01

    Objective: To investigate the mechanism of expression and significance of vascular endothelial growth factor (VEGF) and p53 in degenerate intervertebral disc tissue. Methods: Pathological sections collected from 156 patients with lumbar disc herniation after surgery were tested by immunohistochemistry method, for evaluation of the expression of VEGF and p53 in degenerate intervertebral disc tissue. Results: 98 cases (62.8%) with vascular infiltration phenomenon are found, and positive rates of VEGF and p53 in degenerate intervertebral disc tissue are 73.42%(116/156) and 58.97% (92/156); co-expression rate is 53.2%(83/156); the expression rates of VEFG and p53 are significantly higher in the tissue with blood vessel infiltration than in the tissue without infiltration; there is a close relationship of VEGF with p53. Conclusions: VEGF and p53 gene synergetic express in degenerate intervertebral disc tissue, working together in neovascularization and infiltration, and accelerating intervertebral disc tissue degeneration.

  17. Wild-type p53 and p73 negatively regulate expression of proliferation related genes.

    Scian, M J; Carchman, E H; Mohanraj, L; Stagliano, K E R; Anderson, M A E; Deb, D; Crane, B M; Kiyono, T; Windle, B; Deb, S P; Deb, S

    2008-04-17

    When normal cells come under stress, the wild-type (WT) p53 level increases resulting in the regulation of gene expression responsible for growth arrest or apoptosis. Here we show that elevated levels of WT p53 or its homologue, p73, inhibit expression of a number of cell cycle regulatory and growth promoting genes. Our analysis also identified a group of genes whose expression is differentially regulated by WT p53 and p73. We have infected p53-null H1299 human lung carcinoma cells with recombinant adenoviruses expressing WT p53, p73 or beta-galactosidase, and have undertaken microarray hybridization analyses to identify genes whose expression profile is altered by p53 or p73. Quantitative real-time PCR verified the repression of E2F-5, centromere protein A and E, minichromosome maintenance proteins (MCM)-2, -3, -5, -6 and -7 and human CDC25B after p53 expression. 5-Fluorouracil treatment of colon carcinoma HCT116 cells expressing WT p53 results in a reduction of the cyclin B2 protein level suggesting that DNA damage may indeed cause repression of these genes. Transient transcriptional assays verified that WT p53 repressed promoters of a number of these genes. Interestingly, a gain-of-function p53 mutant instead upregulated a number of these promoters in transient transfection. Using promoter deletion mutants of MCM-7 we have found that WT p53-mediated repression needs a minimal promoter that contains a single E2F site and surrounding sequences. However, a single E2F site cannot be significantly repressed by WT p53. Many of the genes identified are also repressed by p21. Thus, our work shows that WT p53 and p73 repress a number of growth-related genes and that in many instances this repression may be through the induction of p21. PMID:17982488

  18. Activation of p53 pathway by Nutlin-3a inhibits the expression of the therapeutic target alpha 5 integrin in colon cancer cells

    Janoušková, Hana; Ray, A.M.; Noulet, F.; Lelong-Rebel, I.; Choulier, L.; Schaffner, F.; Lehmann, M.; Martin, S.; Teisinger, Jan; Dontenwill, M.

    2013-01-01

    Roč. 336, č. 2 (2013), s. 307-318. ISSN 0304-3835 Institutional support: RVO:67985823 Keywords : colon cancer * integrin alpha 5 beta 1 * p53 * Nutlin-3a Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.016, year: 2013

  19. Clinicopathological significance of p53 and mdm2 protein expression in human pancreatic cancer

    Ming Dong; Gang Ma; Wei Tu; Ke-Jian Guo; Yu-Lin Tian; Yu-Ting Dong

    2005-01-01

    AIM: To study the clinicopathological significance of p53 and mdm2 protein expression in human pancreatic cancer. METHODS: To investigate the expression of p53 and mdm2 in pancreatic cancer by immunohistochemistry, and the relationships between the p53 and mdm2 protein expression and clinicopathological parameters in pancreatic cancer.RESULTS: The positive expression of p53 protein was found in 40 of 59 patients (67.8%) and that of mdm2 protein in 17 of 59 patients (28.8%). No obvious relationships were found between p53 as well as mdm2 expression and sex, tumor site, TNM staging and histological differentiation. p53 expression was increased in patients younger than 65 years old, while mdm2 had no relationship with age. The survival time of the patients with the positive expression of p53 and mdm2 proteins was obviously shorter than the other groups. CONCLUSION: Both p53 and mdm2 presented relatively high expression in human pancreatic cancer. The overexpression of p53 and mdm2 might reflect the malignant proliferation of pancreatic cancer and their co-expression might be helpful to evaluate the prognosis of the patients with pancreatic cancer.

  20. Expression of the p48 xeroderma pigmentosum gene is p53-dependent and is involved in global genomic repair

    Hwang, Byung Joon; Ford, James M; Hanawalt, Philip C.; Chu, Gilbert

    1999-01-01

    In human cells, efficient global genomic repair of DNA damage induced by ultraviolet radiation requires the p53 tumor suppressor, but the mechanism has been unclear. The p48 gene is required for expression of an ultraviolet radiation-damaged DNA binding activity and is disrupted by mutations in the subset of xeroderma pigmentosum group E cells that lack this activity. Here, we show that p48 mRNA levels strongly depend on basal p53 expression and increase further after DNA damage in a p53-depe...

  1. Changes in protein expression in p53 deleted spontaneous thymic lymphomas

    Honoré, Bent; Vorum, Henrik; Pedersen, Anders Elm;

    2004-01-01

    By the use of high-resolution two-dimensional gel electrophoresis and computerized image analysis we investigated and compared the expression of cellular proteins from p53 positive (+/+) mouse thymocytes, p53-/- thymocytes before neoplastic transformation, and from cell lines derived from two...... spontaneous p53-/- thymic lymphomas, SM5 and SM7. A total of around 1500 proteins were detected on individual gels. Only changes in protein expression by a factor of 2 or more were considered. In the thymic lymphoma cells 3-5% of the proteins were found to be differentially regulated when compared with the...... protein expression in p53+/+ and p53-/- thymocytes. Only a minority (13 proteins) of the quantitatively changed proteins were common for the two thymic lymphoma cell lines, suggesting that the p53 deficiency mainly results in genetic dysfunctions which are individual for a given tumor. Two of the detected...

  2. Abrogation of the Transactivation Activity of p53 by BCCIP Down-regulation*

    Meng, Xiangbing; Yue, Jingyin; Liu, Zhihe; Shen, Zhiyuan

    2006-01-01

    The tumor suppression function of p53 is mostly conferred by its transactivation activity, which is inactivated by p53 mutations in ~50% of human cancers. In cancers harboring wild type p53, the p53 transactivation activity may be compromised by other mechanisms. Identifying the mechanisms by which wild type p53 transactivation activity can be abrogated may provide insights into the molecular etiology of cancers harboring wild type p53. In this report, we show that BCCIP, a BRCA2 and CDKN1A-i...

  3. Inhibition of p53 transcriptional activity by human cytomegalovirus UL44.

    Kwon, Yejin; Kim, Mi-Na; Young Choi, Eun; Heon Kim, Jung; Hwang, Eung-Soo; Cha, Chang-Yong

    2012-05-01

    Human cytomegalovirus (HCMV) stimulates cellular synthesis of DNA and proteins and induces transition of the cell cycle from G(1) to S and G(2) /M phase, in spite of increased amounts of p53 in the infected cells. The immediate early protein IE2-86  kDa (IE86) tethers a transcriptional repression domain to p53; however, its repression of p53 function is not enough to abrogate the G(1) checkpoint function of p53. Other HCMV proteins that suppress the activity of p53 were investigated in this study. Of the HCMV proteins that bind to p53 when assessed by immunoprecipitation and immunoblot analysis, HCMV UL44 was chosen as a candidate protein. It was found that reporter gene containing p53 consensus sequence was activated by transfection with wild type p53, but when plasmids of p53 with IE86 or UL44 were co-transfected, p53 transcriptional activity was decreased to 3-7% of the p53 control in a dose-dependent manner. When the deletion mutant of UL44 was co-transected with p53, the carboxyl one-third portion of UL44 had little effect on inhibition of p53 transcriptional activity. The amount of mRNA p21 was measured in H1299 by real time PCR after transfection of the combination of p53 and UL44 vectors and it was found that p21 transcription by p53 was inhibited dose-dependently by UL44. Increased G0/G1 and decreased S phases in p53 wild type-transfected H1299 cells were recovered to the level of p53 mutant type-transfected ones by the additional transfection of UL44 in a dose-dependent manner. In conclusion, the transcriptional activity of p53 is suppressed by UL44 as well as by IE86. PMID:22376288

  4. THE EXPRESSION OF P53 PROTEIN AND P21WAFl/cipl/sdil IN GASTRIC CARCINOMA

    2001-01-01

    Objective To study the relation along p53, p21 protein, p21 gene and their clinical significances in 40 gastric comparing with normal gastric tissues.Methods In this study, the p53 and p21 protein were investigated in 40 gastric carcinomas using IHC(Immunohistochemistry). At the same time, the possible presence of p21 gene mutation was also analyzed by silver staining PCR-SSCP method.Results The abnormal expression of p53 and p21 protein occurs only in gastric carcinoma; The expression of p53 protein and p21 is not related to the clinico pathological features. There was relationship between the expression of p53 protein and p21 protein. In 40 cases of gastric carcinoma, single strand conformational polymorphism of PCR product for p21 gene in tumor tissue shows no altered band or mobility shifting.Conclusion The abnormal expression of p53 and p21 protein occurs only in gastric carcinoma and is not related to the clinicopathological features. The expression of p21 protein is related to that of p53 protein. The mutation of p21 gene was not found in all of 40 tumor specimens. This suggests that p21 alteration in gastric carcinoma is caused through the inactivation of p53 protein rather than through intragenic mutation of the p21 gene itself.Using drugs which can stimulate p21 gene is a new method to cure gastric cancer with mutation-p53 protein.

  5. p53 family members regulate the expression of the apolipoprotein D gene.

    Sasaki, Yasushi; Negishi, Hideaki; Koyama, Ryota; Anbo, Naoki; Ohori, Kanae; Idogawa, Masashi; Mita, Hiroaki; Toyota, Minoru; Imai, Kohzoh; Shinomura, Yasuhisa; Tokino, Takashi

    2009-01-01

    p73 and p63 are members of the p53 gene family that play an important role in development and homeostasis, mainly by regulating transcription of a variety of genes. We report here that apolipoprotein D (apoD), a member of the lipocalin superfamily of lipid transport proteins, is a direct transcriptional target of the p53 family member genes. We found that the expression of apoD was specifically up-regulated by either TAp73 or TAp63 but not significantly by p53. In addition, apoD transcription is activated in response to cisplatin in a manner dependent on endogenous p73. By using small interference RNA designed to target p73, we demonstrated that silencing endogenous p73 abolishes induction of apoD transcription following cisplatin treatment. We also identified a p73/p63-binding site in the promoter of the apoD gene that is responsive to the p53 family members. The ectopic expression of TAp73 as well as the addition of recombinant human apoD to culture medium induced the osteoblastic differentiation of the human osteosarcoma cell line Saos-2, as assessed by alkaline phosphatase activity. Importantly, apoD knockdown abrogated p73-mediated alkaline phosphatase induction. Moreover, TAp73-mediated apoD expression was able to induce morphological differentiation, as well as expression of neuronal markers, in the human neuroblastoma cell line SH-SY5Y. These results suggest that apoD induction may mediate the activity of p73 in normal development. PMID:19001418

  6. p53-mediated activation of the mitochondrial protease HtrA2/Omi prevents cell invasion.

    Yamauchi, Shota; Hou, Yan Yan; Guo, Alvin Kunyao; Hirata, Hiroaki; Nakajima, Wataru; Yip, Ai Kia; Yu, Cheng-han; Harada, Ichiro; Chiam, Keng-Hwee; Sawada, Yasuhiro; Tanaka, Nobuyuki; Kawauchi, Keiko

    2014-03-31

    Oncogenic Ras induces cell transformation and promotes an invasive phenotype. The tumor suppressor p53 has a suppressive role in Ras-driven invasion. However, its mechanism remains poorly understood. Here we show that p53 induces activation of the mitochondrial protease high-temperature requirement A2 (HtrA2; also known as Omi) and prevents Ras-driven invasion by modulating the actin cytoskeleton. Oncogenic Ras increases accumulation of p53 in the cytoplasm, which promotes the translocation of p38 mitogen-activated protein kinase (MAPK) into mitochondria and induces phosphorylation of HtrA2/Omi. Concurrently, oncogenic Ras also induces mitochondrial fragmentation, irrespective of p53 expression, causing the release of HtrA2/Omi from mitochondria into the cytosol. Phosphorylated HtrA2/Omi therefore cleaves β-actin and decreases the amount of filamentous actin (F-actin) in the cytosol. This ultimately down-regulates p130 Crk-associated substrate (p130Cas)-mediated lamellipodia formation, countering the invasive phenotype initiated by oncogenic Ras. Our novel findings provide insights into the mechanism by which p53 prevents the malignant progression of transformed cells. PMID:24662565

  7. Correlation and Expression of COX-2 and P53 Protein in Basal Cell Carcinoma of Eyelid

    Zhixiong CHEN; Jiong YANG; Qiong HUANG

    2009-01-01

    .01). Spearman rank correlation analysis demonstrated a positive correlation between the expression of COX-2 and p53 (r=0.113, P=0.421). It was concluded that COX-2 can increase the expression of p53 protein, therefore suppressing apop-tosis.

  8. OTUD5 regulates p53 stability by deubiquitinating p53.

    Judong Luo

    Full Text Available BACKGROUND: The p53 tumour suppressor protein is a transcription factor that prevents oncogenic progression by activating the expression of apoptosis and cell-cycle arrest genes in stressed cells. The stability of p53 is tightly regulated by ubiquitin-dependent degradation, driven mainly by its negative regulators ubiquitin ligase MDM2. PRINCIPAL FINDINGS: In this study, we have identified OTUD5 as a DUB that interacts with and deubiquitinates p53. OTUD5 forms a direct complex with p53 and controls level of ubiquitination. The function of OTUD5 is required to allow the rapid activation of p53-dependent transcription and a p53-dependent apoptosis in response to DNA damage stress. CONCLUSIONS: As a novel deubiquitinating enzyme for p53, OTUD5 is required for the stabilization and the activation of a p53 response.

  9. Gene expression of P53 and adipoq as diagnostic markers for colorectal cancer

    Nadhum Jalal Ismaiel; Rozhgar Abdullah Mohammed; Hazha Jamal Hidayat

    2016-01-01

    Purpose: Colorectal cancer is the most frequent cause of death and had high mortality rate in Western world. It is from complex, variable and patient- specific interaction between genetic, epigenetic and environmental factors. In the present study, we aimed to investigate the contribution of gene expression of the P53 and Adipoq, both genes to the risk of colorectal cancer. P53 gene is a tumor suppressor gene, encoded protein of P53 is a transcription factor and its pivotal role in maintaini...

  10. Residues in the alternative reading frame tumor suppressor that influence its stability and p53-independent activities

    The Alternative Reading Frame (ARF) protein suppresses tumorigenesis through p53-dependent and p53-independent pathways. Most of ARF's anti-proliferative activity is conferred by sequences in its first exon. Previous work showed specific amino acid changes occurred in that region during primate evolution, so we programmed those changes into human p14ARF to assay their functional impact. Two human p14ARF residues (Ala14 and Thr31) were found to destabilize the protein while two others (Val24 and Ala41) promoted more efficient p53 stabilization and activation. Despite those effects, all modified p14ARF forms displayed robust p53-dependent anti-proliferative activity demonstrating there are no significant biological differences in p53-mediated growth suppression associated with simian versus human p14ARF residues. In contrast, p53-independent p14ARF function was considerably altered by several residue changes. Val24 was required for p53-independent growth suppression whereas multiple residues (Val24, Thr31, Ala41 and His60) enabled p14ARF to block or reverse the inherent chromosomal instability of p53-null MEFs. Together, these data pinpoint specific residues outside of established p14ARF functional domains that influence its expression and signaling activities. Most intriguingly, this work reveals a novel and direct role for p14ARF in the p53-independent maintenance of genomic stability.

  11. The p53 pathway in breast cancer

    Gasco, Milena; Shami, Shukri; Crook, Tim

    2002-01-01

    p53 mutation remains the most common genetic change identified in human neoplasia. In breast cancer, p53 mutation is associated with more aggressive disease and worse overall survival. The frequency of mutation in p53 is, however, lower in breast cancer than in other solid tumours. Changes, both genetic and epigenetic, have been identified in regulators of p53 activity and in some downstream transcriptional targets of p53 in breast cancers that express wild-type p53. Molecular pathological an...

  12. Gene expression profiling analysis reveals arsenic-induced cell cycle arrest and apoptosis in p53-proficient and p53-deficient cells through differential gene pathways

    Arsenic (As) is a well-known environmental toxicant and carcinogen as well as an effective chemotherapeutic agent. The underlying mechanism of this dual capability, however, is not fully understood. Tumor suppressor gene p53, a pivotal cell cycle checkpoint signaling protein, has been hypothesized to play a possible role in mediating As-induced toxicity and therapeutic efficiency. In this study, we found that arsenite (As3+) induced apoptosis and cell cycle arrest in a dose-dependent manner in both p53+/+ and p53-/- mouse embryonic fibroblasts (MEFs). There was, however, a distinction between genotypes in the apoptotic response, with a more prominent induction of caspase-3 in the p53-/- cells than in the p53+/+ cells. To examine this difference further, a systems-based genomic analysis was conducted comparing the critical molecular mechanisms between the p53 genotypes in response to As3+. A significant alteration in the Nrf2-mediated oxidative stress response pathway was found in both genotypes. In p53+/+ MEFs, As3+ induced p53-dependent gene expression alterations in DNA damage and cell cycle regulation genes. However, in the p53-/- MEFs, As3+ induced a significant up-regulation of pro-apoptotic genes (Noxa) and down-regulation of genes in immune modulation. Our findings demonstrate that As-induced cell death occurs through a p53-independent pathway in p53 deficient cells while apoptosis induction occurs through p53-dependent pathway in normal tissue. This difference in the mechanism of apoptotic responses between the genotypes provides important information regarding the apparent dichotomy of arsenic's dual mechanisms, and potentially leads to further advancement of its utility as a chemotherapeutic agent

  13. Cadmium Impairs p53 Activity in HepG2 Cells.

    Urani, C; Melchioretto, P; Fabbri, M; Bowe, G; Maserati, E; Gribaldo, L

    2014-01-01

    Cadmium and cadmium compounds are contaminants of the environment, food, and drinking water and are important constituents of cigarette smoke. Cd exposure has also been associated with airborne particulate CdO and with Cd-containing quantum dots in medical therapy. Adverse cadmium effects reported in the literature have stimulated during recent years an ongoing discussion to better elucidate cadmium outcomes at cell and molecular level. The present work is designed to gain an insight into the mechanism of p53 impairment at gene and protein level to understand Cd-induced resistance to apoptosis. We used a hepatoma cell line (HepG2) derived from liver, known to be metal responsive. At genotoxic cadmium concentrations no cell cycle arrest was observed. The p53 at gene and protein level was not regulated. Fluorescence images showed that p53 was correctly translocated into the nucleus but that the p21(Cip1/WAF-1), a downstream protein of p53 network involved in cell cycle regulation, was not activated at the highest cadmium concentrations used. The miRNAs analysis revealed an upregulation of mir-372, an miRNA able to affect p21(Cip1/WAF-1) expression and promote cell cycle progression and proliferation. The role of metallothioneins and possible conformational changes of p53 are discussed. PMID:25101185

  14. p53 isoforms change p53 paradigm

    Bourdon, JC

    2014-01-01

    Although p53 defines cellular responses to cancer treatment it is not clear how p53 can be used to control cell fate outcome. Data demonstrate that so-called p53 does not exist as a single protein, but is in fact a group of p53 protein isoforms whose expression can be manipulated to control the cellular response to treatment.

  15. Effect of Boschniakia rossica on expression of GST-P, p53 and p21(ras)proteins in early stage of chemical hepatocarcinogenesis and its anti-inflammatory activities in rats.

    Yin, Zong-Zhu; Jin, Hai-Ling; Yin, Xue-Zhe; Li, Tian-Zhu; Quan, Ji-Shu; Jin, Zeng-Nan

    2000-12-01

    AIM:To investigate the effect of Boschniakia rossica (BR) extract on expression of GST-P, p53 and p21(ras) proteins in early stage of chemical hepatocarcinogenesis in rats and its anti-inflammatory activities.METHODS:The expression of tumor marker-placental form glutathione S-transferase (GST-P), p53 and p21(ras) proteins were investigated by immunohisto-chemical techniques and ABC method. Anti-inflammatory activities of BR were studied by xylene and croton oil-induced mouse ear edema, carrageenin, histamine and hot scald-induced rat pow edema, adjuvant-induced rat arthritis and cotton pellet induced mouse granuloma formation methods.RESULTS:The 500mg/kg of BR-H2O extract frac-tionated from BR-Methanol extract had inhibitory effect on the formation of DEN-induced GST-P-positive foci in rat liver (GST-P staining was 78% positive in DEN+AAF group vs 20% positive in DEN+AAF+BR group, P<0.05) and the expression of mutant p53 and p21(ras) protein was lower than that of hepatic preneoplastic lesions (33% and 22% positive respectively in DEN+AAF group vs negative in DEN+AAF+BR group). Both CH(2)Cl(2) and H(2)O extracts from BR had anti-inflamatory effect in xylene and crotonoil induced mouse ear edema (inhibitory rates were 26%-29% and 35%-59%, respectively). BR H(2)O extract exhibited inhibitory effect in carrageenin, histamine and hot scald-induced hind paw edema and adjuvant-induced arthritis in rats and cotton pellet-induced granuloma formation in mice.CONCLUSION:BR extract exhibited inhibitory effect on formation of preneoplastic hepatic foci in early stage of rat chemical hepato-carcinogenesis.Both CH(2)Cl(2) and H(2)O extracts from BR exerted anti-inflammatory effect in rats and mice. PMID:11819701

  16. Mdm2 is a novel activator of ApoCIII promoter which is antagonized by p53 and SHP inhibition

    Highlights: ► Mdm2 enhances HNF4α activation of the ApoCIII promoter via interaction with HNF4α. ► p53 antagonizes the effect of Mdm2 activation of the ApoCIII promoter. ► SHP strengthens p53 inhibition but abolishes Mdm2 activation of the ApoCIII promoter. ► Mdm2 alters the enrichment of HNF4α, p53 and SHP to the ApoCIII promoter. -- Abstract: We examined the effect of Mdm2 on regulation of the ApoCIII promoter and its cross-talk with p53 and nuclear receptor SHP. Overexpression of Mdm2 markedly enhanced ApoCIII promoter activity by HNF4α. A direct association of Mdm2 protein with the HNF4α protein was observed by co-immunoprecipitation. Ectopic expression of p53 decreased HNF4α activation of the ApoCIII promoter and antagonized the effect of Mdm2. Co-expression of SHP further strengthened p53 inhibition and abolished Mdm2 activation of the ApoCIII promoter. Mdm2 inhibited p53-mediated enrichment of HNF4α to the ApoCIII promoter while simultaneously reducing p53 binding and increasing recruitment of SHP to the ApoCIII promoter. The results from this study implicate a potentially important function of Mdm2 in regulation of lipoprotein metabolism.

  17. Tumor suppressor p53 protein expression: prognostic significance in patients with low-risk myelodysplastic syndrome

    Fernando Barroso Duarte

    2014-06-01

    Full Text Available BACKGROUND: At the time of diagnosis, more than 50% of patients with myelodysplastic syndrome have a normal karyotype and are classified as having a favorable prognosis. However, these patients often show very variable clinical outcomes. Furthermore, current diagnostic tools lack the ability to look at genetic factors beyond karyotyping in order to determine the cause of this variability.OBJECTIVE: To evaluate the impact of p53 protein expression at diagnosis in patients with low-risk myelodysplastic syndrome.METHODS: This study enrolled 38 patients diagnosed with low-risk myelodysplastic syndrome. Clinical data were collected by reviewing medical records, and immunohistochemical p53 staining was performed on bone marrow biopsies.RESULTS: Of the 38 participants, 13 (34.21% showed p53 expression in their bone marrow. At diagnosis, this group of patients also presented clinical features characteristic of a poor prognosis more often than patients who did not express p53. Furthermore, patients expressing p53 had a shorter median survival time compared to those without p53 expression.CONCLUSION: This study shows that the expression of p53 at diagnosis is a useful indicator of distinct clinical characteristics and laboratory profiles found in low-risk myelodysplastic syndrome patients. These data indicate that the immunohistochemical analysis of p53 may be a prognostic tool for myelodysplastic syndrome and should be used as an auxiliary test to help determine the best therapeutic choice.

  18. p53 expression in synovial sarcoma and its association with prognostic factors

    Muhammad I. Ilmiawan

    2012-11-01

    Full Text Available Background: Synovial sarcoma is an aggressive tumor and has two common histological subtype, biphasic and monophasic. It has SYT-SSX gene fusion that decreases expression of p53 tumor suppressor. The prognosis is associated with mitosis and tumor diameter. Therefore this study conducted to know the pattern of p53 expresion and its association with mitosis, histological subtype, and other prognosis factors.Methods: Twenty synovial sarcoma cases consisted of 4 monophasic and 16 biphasic cases from Cipto Mangunkusumo Hospital – Faculty of Medicine, Universitas Indonesia (CMHospital-FMUI 2005-2011 were analyzed for association of p53 expression and mitosis as prognostic factor. Haematoxylin-eosin slides were used to count mitosis. Paraffin block materials were used to analyze p53 expression by immunohistochemistry and to detect SYT gene translocation by FISH (Fluorescein in situ Hybridization.Results: The Fisher’s exact test showed that positive p53 expression was associated with tumor diameter <5 cm although it was not associated with mitosis. The histological subtype has no association with p53 expression and mitosis. Unfortunately, only 7/19 cases were positive for FISH-SYT gene translocation.Conclusion: In synovial sarcoma, p53 expression is associated with tumor diameter. (Med J Indones. 2012;21:196-202Keywords: Mitosis, p53, synovial sarcoma, SYT-SSX fusion gene

  19. Prognostic significance of bcl-2 and p53 expression in colorectal carcinoma

    ZHAO Dan-ping; DING Xiao-wen; PENG Jia-ping; ZHENG Yi-xiong; ZHANG Su-zhan

    2005-01-01

    Objective: This study was designed to detect the expression ofbcl-2 and p53 proteins in colorectal carcinomas and to determine their association with the patient survival and stage of the diseases. Methods: Immunohistochemistry method was used to detect the expression ofbcl-2 and p53 proteins in 93 cases of colorectal carcinoma. The stain results were obtained by analyzing the clinic-pathological characteristics of patients. Results: Fifty-seven percent (53/93) of the colorectal carcinomas were bcl-2 protein positive. The positive rate of bcl-2 protein in lymph node involvement cases was lower (15/37) than the cases without node involvement (38/58, P<0.01). The positive rate of p53 protein was 43% (40/93) in colon-rectum carcinomas. No significant correlation was observed between p53 protein expression and clinic-pathological manifestations (P>0.05) but the survival was significantly worse (P=0.0001) in the p53 protein positive cases. Neither bcl-2 nor p53 alone was correlated with stage of the disease. When combined bcl-2/p53 status was analyzed, a group with bcl-2(+) and p53(-) had the best prognosis. This group was significantly associated with earlier Dukes' stages (P=0.1763). In multivariate Cox regression analysis, lymph node involvement and p53 protein expression were two independent factors correlated with survival time. Conclusion: The expression of bcl-2 and p53 represent biological characteristics of colorectal carcinomas. Assessment of both bcl-2 and p53 status may be valuable in predicting the prognosis of patients.

  20. Expression of nitric oxide synthase in human gastric carcinoma and its relation to p53, PCNA

    Yong-Zhong Wang; You-Qing Cao; Jian-Nong Wu; Miao Chen; Xiao-Ying Cha

    2005-01-01

    AIM: To investigate the expression of NOS in gastric carcinoma, and to explore the relationship between the expression of nitric oxide synthases (NOS) and p53, PCNA,pathological features and clinical staging of gastric cancer.METHODS: The activity of NOS protein was investigated in 85 samples of human gastric carcinoma and 25 samples of normal gastric mucosal tissue by biochemical assay. We then examined the expression of NOS, p53, PCNA in 85 samples of human gastric cancer was examined by immunohistochemistry, and NOS mRNA expression in 85 gastric cancer tissue specimens by in situ hybridization.RESULTS: Biochemical assay showed that the activity of NOS was significantly higher in gastric carcinoma than in normal gastric mucosal tissues (t = 0.4161, P<0.01).Immunohistochemistry revealed that endothelial nitric oxide synthase (eNOS) expressed in all samples of normal gastric mucosa, but only 6 cases of 85 gastric cancer specimens showed weak positive immunohistochemical reactions to eNOS (20%). Inducible nitric oxide synthase (iNOS) was expressed strongly in human gastric carcinoma (81.2%). In situ hybridization analysis showed that iNOS mRNA expression was significantly stronger than eNOS mRNA expression in gastric cancer tissue (x2 = 10.23, P<0.01). The expression of iNOS in gastric cancer was associated with differentiation, clinical stages or lymph node metastases (r= 0.3426, P<0.05). However,iNOS expression did not correlate with histological classifications and morphological types. The expression of iNOS was significantly correlated with p53 or PCNA expression (r = 0.3612, P<0.05). The expression of neuronal nitric oxide synthase (nNOS) was not examined by immunohistochemistry and in situ hybridization in gastric cancer specimens and normal gastric mucosa.CONCLUSION: In human gastric cancer, there is an enhanced expression of iNOS, but not of eNOS. NOS promotes the proliferation of tumor cells and plays an important role in gastric cancer spread

  1. Attenuation of p53 expression and Bax down-regulation during phorbol ester mediated inhibition of apoptosis

    Meßmer, Udo K; Brüne, Bernhard

    1997-01-01

    Nitric oxide (NO) caused apoptotic cell death in murine RAW 264.7 macrophages. Associated with apoptotic morphology we observed p53 up-regulation and increased Bax expression. 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C (PKC) activator potently blocked NO-induced apoptosis. To gain insights into the mechanisms involved we investigated the effect of TPA on apoptotic conveying proteins such as p53 and Bax.TPA (100 nM) attentuated p53 up-regulation elicited by the NO-releasing...

  2. TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

    Ding, Li [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); College of Life Sciences, Hainan Normal University, Haikou, Hainan 571158 (China); Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China); Tong, Dewen, E-mail: dwtong@nwsuaf.edu.cn [College of Veterinary Medicine, Northwest A and F University, Yangling, Shaanxi 712100 (China)

    2014-03-07

    Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence.

  3. Nuclear accumulation and activation of p53 in embryonic stem cells after DNA damage

    Rolletschek Alexandra; Solozobova Valeriya; Blattner Christine

    2009-01-01

    Abstract Background P53 is a key tumor suppressor protein. In response to DNA damage, p53 accumulates to high levels in differentiated cells and activates target genes that initiate cell cycle arrest and apoptosis. Since stem cells provide the proliferative cell pool within organisms, an efficient DNA damage response is crucial. Results In proliferating embryonic stem cells, p53 is localized predominantly in the cytoplasm. DNA damage-induced nuclear accumulation of p53 in embryonic stem cells...

  4. SCH529074, a Small Molecule Activator of Mutant p53, Which Binds p53 DNA Binding Domain (DBD), Restores Growth-suppressive Function to Mutant p53 and Interrupts HDM2-mediated Ubiquitination of Wild Type p53

    Demma, Mark; Maxwell, Eugene; Ramos, Robert; Liang, Lianzhu; Li, Cheng; Hesk, David; Rossman, Randall; Mallams, Alan; Doll, Ronald; Liu, Ming; Seidel-Dugan, Cynthia; Bishop, W. Robert; Dasmahapatra, Bimalendu

    2010-01-01

    Abrogation of p53 function occurs in almost all human cancers, with more than 50% of cancers harboring inactivating mutations in p53 itself. Mutation of p53 is indicative of highly aggressive cancers and poor prognosis. The vast majority of mutations in p53 occur in its core DNA binding domain (DBD) and result in inactivation of p53 by reducing its thermodynamic stability at physiological temperature. Here, we report a small molecule, SCH529074, that binds specifically to the p53 DBD in a sat...

  5. p53 and Rb1 protein expression: are they prognostically useful in colorectal cancer?

    Poller, D. N.; Baxter, K J; Shepherd, N A

    1997-01-01

    The expression of the p53 and Rb1 proteins was examined in an unselected consecutive series of 250 primary operable colorectal carcinomas with a mean follow-up of 4.3 years (range 43-77 months). The overall cancer-specific mortality was 34.8%, with 87 cancer deaths and 35 deaths as the result of other causes. Expression of p53 protein was identified in 152 of 250 (60.8%) cases, with expression of Rb1 protein in 207 of 250 (82.8%) cases. There was no association of p53 or Rb protein expression...

  6. Magnetite nanoparticles inhibit tumor growth and upregulate the expression of p53/p16 in Ehrlich solid carcinoma bearing mice.

    Heba Bassiony

    Full Text Available BACKGROUND: Magnetite nanoparticles (MNPs have been widely used as contrast agents and have promising approaches in cancer treatment. In the present study we used Ehrlich solid carcinoma (ESC bearing mice as a model to investigate MNPs antitumor activity, their effect on expression of p53 and p16 genes as an indicator for apoptotic induction in tumor tissues. METHOD: MNPs coated with ascorbic acid (size: 25.0±5.0 nm were synthesized by co-precipitation method and characterized. Ehrlich mice model were treated with MNPs using 60 mg/Kg day by day for 14 injections; intratumorally (IT or intraperitoneally (IP. Tumor size, pathological changes and iron content in tumor and normal muscle tissues were assessed. We also assessed changes in expression levels of p53 and p16 genes in addition to p53 protein level by immunohistochemistry. RESULTS: Our results revealed that tumor growth was significantly reduced by IT and IP MNPs injection compared to untreated tumor. A significant increase in p53 and p16 mRNA expression was detected in Ehrlich solid tumors of IT and IP treated groups compared to untreated Ehrlich solid tumor. This increase was accompanied with increase in p53 protein expression. It is worth mentioning that no significant difference in expression of p53 and p16 could be detected between IT ESC and control group. CONCLUSION: MNPs might be more effective in breast cancer treatment if injected intratumorally to be directed to the tumor tissues.

  7. The novel fusion proteins, GnRH-p53 and GnRHIII-p53, expression and their anti-tumor effect.

    Peiyuan Jia

    Full Text Available p53, one of the most well studied tumor suppressor factor, is responsible to a variety of damage owing to the induction of apoptosis and cell cycle arrest in the tumor cells. More than 50% of human tumors contain mutation or deletion of p53. Gonadotrophin-releasing hormone (GnRH, as the ligand of Gonadotrophin-releasing hormone receptor (GnRH-R, was used to deliver p53 into tumor cells. The p53 fusion proteins GnRH-p53 and GnRH iii-p53 were expressed and their targeted anti-tumor effects were determined. GnRH mediates its fusion proteins transformation into cancer cells. The intracellular delivery of p53 fusion proteins exerted the inhibition of the growth of H1299 cells in vitro and the reduction of tumor volume in vivo. Their anti-tumor effect was functioned by the apoptosis and cell cycle arrest induced by p53. Hence, the fusion protein could be a novel protein drug for anti-tumor therapy.

  8. Wild-type p53 gene expression sensitizes radioresistant esophageal cancer cell lines

    Objective: To define the radiosensitizing effect of wild-type p3 (Wt-p53) on human radioresistant esophageal cancer cell lines and the application of p53 gene therapy combined with radiotherapy. Methods: The human esophageal cancer cell lines TE-13 and its radioresistant variant TE-13R50 derived from repeated irradiation were initially transfected with Ad5CMV-p53, a recombined adenovirus vector containing human Wt-p53 cDNA and cytomegalovirus (CMV) promoter. The impact of Ad5CMV-p53 expression on radiation sensitivity was observed and analyzed both after transfected cell lines (in vitro) and their transplanted tumors (in vivo) had been irradiated. Results: Significant difference in radiosensitivity between the TE-13 (D0= 1.38 Gy) and TE-13R50 (D0 = 2.48 Gy) cell lines was confirmed. When Ad5CMV-p53 had been transfected and expressed in there cells, their sensitivity to irradiation was enhanced obviously, with declined D0 values of 0.97 Gy and 1.14 Gy, respectively. On the other hand, the growth rate of transplanted tumors in nude mice was more suppressed by combined radiation and injection of Ad5CMV-p53, as compared with irradiation alone, especially for TE-13R50. Conclusion: The potentiation of adenovirus-mediated wt-p53 gene expression has a significant impact on improving the radiosensitivity of esophageal cancer cell lines

  9. Epstein-Barr virus nuclear antigen 3C targets p53 and modulates its transcriptional and apoptotic activities

    The p53 tumor suppressor gene is one of the most commonly mutated genes in human cancers and the corresponding encoded protein induces apoptosis or cell-cycle arrest at the G1/S checkpoint in response to DNA damage. To date, previous studies have shown that antigens encoded by human tumor viruses such as SV40 large T antigen, adenovirus E1A and HPV E6 interact with p53 and disrupt its functional activity. In a similar fashion, we now show that EBNA3C, one of the EBV latent antigens essential for the B-cell immortalization in vitro, interacts directly with p53. Additionally, we mapped the interaction of EBNA3C with p53 to the C-terminal DNA-binding and the tetramerization domain of p53, and the region of EBNA3C responsible for binding to p53 was mapped to the N-terminal domain of EBNA3C (residues 130-190), previously shown to interact with a number of important cell-cycle components, specifically SCFSkp2, cyclin A, and cMyc. Furthermore, we demonstrate that EBNA3C substantially represses the transcriptional activity of p53 in luciferase based reporter assays, and rescues apoptosis induced by ectopic p53 expression in SAOS-2 (p53-/-) cells. Interestingly, we also show that the DNA-binding ability of p53 is diminished in the presence of EBNA3C. Thus, the interaction between the p53 and EBNA3C provides new insights into the mechanism(s) by which the EBNA3C oncoprotein can alter cellular gene expression in EBV associated human cancers.

  10. Preliminary study of p53 and c-erbB-2 expression in gallbladder cancer in Indian patients

    Singh Usha

    2006-05-01

    Full Text Available Abstract Background The inactivation of the tumour suppressor gene and activation of the proto-oncogene are the key steps in the development of the human cancer. The p53 and c-erbB-2 are the best examples of it. In the present study, our aim was to determine the role of these genes in the carcinogenesis of gallbladder by immunohistochemistry. Methods In all 78 consecutive patients of gall bladder diseases were studied for p53 and c-erbB-2 expression immunohistochemically and their expression was correlated with the age, grades and stages of the disease and presence of stone. An informed consent was obtained in each case. Chi square and z test were applied to see the association of p53 and c-erbB-2 over expression with other clinicopathological factors. Results Eight (20% patients of gall bladder cancer were positive for p53 expression and 10 (25% patients for c-erbB-2. The p53 positivity increased with increasing grade while cerbB-2 positivity decreased with increasing grade of gall bladder cancer. Mean age in cerbB-2 positive cases were lesser as compared to negative cases while p53 did not show such association with age. Conclusion Only one case of gall bladder cancer co-expressed the p53 and c-erbB-2, thereby suggesting that p53 and c-erbB-2 may have independent role in carcinogenesis of gall bladder cancer. c-erbB-2 over expression in adenoma and younger age group indicates its role as an early event in carcinogenesis of gallbladder. However study of larger sample is required to further validate the results.

  11. EXPRESSION OF P53 PROTEIN AND PROLIFERATING CELL NUCLEAR ANTIGEN IN HUMAN GESTATION TROPHOBLASTIC DISEASE

    黄铁军; 王志忠; 方光光; 刘志恒

    2004-01-01

    Objective: To study the relationship between p53 protein, proliferating cell nuclear antigen (PCNA) expression and benign or malignant gestational trophoblastic disease (MGTD). Methods: The histotomic sections of 48 patients with gestational trophoblastic disease and 24 patients of normal chorionic villi were stained using immunohistochemistry. The monoclonal antibodies were used to determine p53 protein and PCNA. Results: The frequency of p53 and PCNA positive expression were significantly different among the chorionic villi of normal pregnancy, hydratidiform mole (HM) and MGTD. But neither p53 nor PCNA has any relation with the clinical staging or metastasis of MGTD. Conclusion: Both P53 and PCNA are valuable in diagnosis of human gestational trophoblastic disease.

  12. Nuclear accumulation and activation of p53 in embryonic stem cells after DNA damage

    Rolletschek Alexandra

    2009-06-01

    Full Text Available Abstract Background P53 is a key tumor suppressor protein. In response to DNA damage, p53 accumulates to high levels in differentiated cells and activates target genes that initiate cell cycle arrest and apoptosis. Since stem cells provide the proliferative cell pool within organisms, an efficient DNA damage response is crucial. Results In proliferating embryonic stem cells, p53 is localized predominantly in the cytoplasm. DNA damage-induced nuclear accumulation of p53 in embryonic stem cells activates transcription of the target genes mdm2, p21, puma and noxa. We observed bi-phasic kinetics for nuclear accumulation of p53 after ionizing radiation. During the first wave of nuclear accumulation, p53 levels were increased and the p53 target genes mdm2, p21 and puma were transcribed. Transcription of noxa correlated with the second wave of nuclear accumulation. Transcriptional activation of p53 target genes resulted in an increased amount of proteins with the exception of p21. While p21 transcripts were efficiently translated in 3T3 cells, we failed to see an increase in p21 protein levels after IR in embryonal stem cells. Conclusion In embryonic stem cells where (anti-proliferative p53 activity is not necessary, or even unfavorable, p53 is retained in the cytoplasm and prevented from activating its target genes. However, if its activity is beneficial or required, p53 is allowed to accumulate in the nucleus and activates its target genes, even in embryonic stem cells.

  13. Frequency of p53 Gene Mutation and Protein Expression in Oral Squamous Cell Carcinoma

    Objective: To determine the frequency of p53 gene mutation and protein expression in Oral Squamous Cell Carcinoma (OSCC) and to establish correlation between the two. Study Design: Analytical study. Place and Duration of Study: Histopathology Department and Molecular Biology Laboratory, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from May 2010 to May 2011. Methodology: Thirty diagnosed cases of OSCC were selected by consecutive sampling. Seventeen were retrieved from the record files of the AFIP, and 13 fresh/frozen sections were selected from patients reporting to the Oral Surgery Department, Armed Forces Institute of Dentistry (AFID). Gene p53 mutation was analyzed in all the cases using PCRSSCP analysis. DNA was extracted from the formalin-fixed and paraffin-embedded tissue sections and fresh/frozen sections. DNA thus extracted was amplified by polymerase chain reaction. The amplified products were denatured and finally analyzed by gel electrophoresis. Gene mutation was detected as electrophoretic mobility shift. The immunohistochemical marker p53 was applied to the same 30 cases and overexpression of protein p53 was recorded. Results: Immunohistochemical expression of marker p53 was positive in 67% (95% Confidence Interval (CI) 48.7 - 80.9) of the cases. Mutations of the p53 gene were detected in 23% (95% CI 11.5 - 41.2) of the OSCC. No statistically significant correlation was found between p53 gene mutation and protein p53 expression (rs = - 0.057, p = 0.765). Conclusion: A substantial number of patients have p53 gene mutation (23%) and protein p53 expression (67%) in oral squamous cell carcinoma (OSCC). (author)

  14. Radioresistance of human glioma spheroids and expression of HSP70, p53 and EGFr

    Radiation therapy is routinely prescribed for high-grade malignant gliomas. However, the efficacy of this therapeutic modality is often limited by the occurrence of radioresistance, reflected as a diminished susceptibility of the irradiated cells to undergo cell death. Thus, cells have evolved an elegant system in response to ionizing radiation induced DNA damage, where p53, Hsp70 and/or EGFr may play an important role in the process. In the present study, we investigated whether the content of p53, Hsp70 and EGFr are associated to glioblastoma (GBM) cell radioresistance. Spheroids from U-87MG and MO59J cell lines as well as spheroids derived from primary culture of tumor tissue of one GBM patient (UGBM1) were irradiated (5, 10 and 20 Gy), their relative radioresistance were established and the p53, Hsp70 and EGFr contents were immunohistochemically determined. Moreover, we investigated whether EGFr-phospho-Akt and EGFr-MEK-ERK pathways can induce GBM radioresistance using inhibitors of activation of ERK (PD098059) and Akt (wortmannin). At 5 Gy irradiation UGBM1 and U-87MG spheroids showed growth inhibition whereas the MO59J spheroid was relatively radioresistant. Overall, no significant changes in p53 and Hsp70 expression were found following 5 Gy irradiation treatment in all spheroids studied. The only difference observed in Hsp70 content was the periphery distribution in MO59J spheroids. However, 5 Gy treatment induced a significant increase on the EGFr levels in MO59J spheroids. Furthermore, treatment with inhibitors of activation of ERK (PD098059) and Akt (wortmannin) leads to radiosensitization of MO59J spheroids. These results indicate that the PI3K-Akt and MEK-ERK pathways triggered by EGFr confer GBM radioresistance

  15. Expression and Prognostic Significance of p53 in Glioma Patients: A Meta-analysis.

    Jin, Yueling; Xiao, Weizhong; Song, Tingting; Feng, Guangjia; Dai, Zhensheng

    2016-07-01

    Glioma is a brain tumor deriving from the neoplastic glial cells or neuroglia. Due to its resistance to anticancer drugs and different disease progress of individuals, patients with high-grade glioma are difficult to completely cure, leading to a poor prognosis and low overall survival. Therefore, there is an urgent need to look for prognostic and diagnostic indicators that can predict glioma grades. P53 is one of the widely studied biomarkers in human glioma. The purpose of this study was to comprehensively evaluate the significance of p53 expression in glioma grades and overall survival. We searched commonly used electronic databases to retrieve related articles of p53 expression in glioma. Overall, a total of 21 studies including 1322 glioma patients were finally screened out. We observed that the frequency of p53 immuno-positivity was higher in high-grade patients than that in low-grade category (63.8 vs. 41.6 %), and our statistic analysis indicated that p53 expression was associated with pathological grade of glioma (OR 2.93, 95 % CI 1.87-4.60, P < 0.00001). This significant correction was also found in 1-, 3- and 5-year overall survival. However, no positive relationship was found between age, sex, tumor size and p53 expression in patients with glioma. In conclusion, our results suggested that p53 immunohistochemical expression might have an effective usefulness in predicting the prognosis in patients with glioma. PMID:27038932

  16. Adenoviral-mediated p53 transgene expression sensitizes both wild-type and null p53 prostate cancer cells in vitro to radiation

    Purpose/Objective: The effect of adenoviral-mediated p53 transgene expression on the radiation response of two human prostate cancer cell lines, the p53wild-type LNCaP and p53null PC3 lines, was examined. The objective was to determine if this vector sensitizes cells to radiation independently of their p53 status. Methods and Materials: A recombinant adenovirus-5 vector (RPR/INGN 201, Introgen Therapeutics, Houston, TX) containing a CMV promoter and wild-type p53-cDNA (Ad5-p53) was used to facilitate p53 transgene expression. A multiplicity of infection (MOI) of 10-40 viral particles per cell was used, based on Ad5/CMV/lacz infection and staining for the β-galactosidase reporter gene product. Clonogenic assays were performed to evaluate the degree of sensitization to radiation of viral-transduced cells compared with irradiated nontransduced controls. The relative efficacy of these treatments to induce apoptotic cell death was determined using the TUNEL assay. Results: The delivery of Ad5-p53 (10 MOI) reduced control plating efficiency from 36.5% to 0.86% in the LNCaP cell line and from 75.1% to 4.1% in the PC3 cell line. After correcting for the effect of Ad5-p53 on plating efficiency, the surviving fraction after 2 Gy (SF2) of gamma-irradiation was reduced over 2.5-fold, from 0.187 to 0.072, with transgene p53 expression in the LNCaP cell line. Surviving fraction after 4 Gy (SF4) was reduced over 4.5-fold, from 0.014 to 0.003, after Ad5-p53 treatment. In the PC3 cell line, Ad5-p53 (40 MOI) reduced SF2 over 1.9-fold from 0.708 to 0.367, and SF4 over 6-fold from 0.335 to 0.056. In both the LNCaP and PC3 cell lines, the combination of Ad5-p53 plus radiation (2 Gy) resulted in supra-additive apoptosis (∼20% for LNCaP and ∼15% for PC3 at 50 MOI), above that seen from the addition of the controls; control vector Ad5-pA plus RT (0.15% for LNCaP and 1.44% for PC3), Ad5-p53 alone (28.6% for LNCaP and 21.7% for PC3), RT alone (0% for LNCaP and 0.23% for PC3), or Ad5-p

  17. Anal cancer in Chinese: human papillomavirus infection and altered expression of p53

    1998-01-01

    AIM To detect the presence of HPV DNA and study the alteration of p53 expression in anal cancers in Chinese.METHODS HPV DNA was amplified by PCR. The amplified HPV DNA was classified by DBH. HPV antigen and p53 expression were respectively detected by immunohistochemistry.RESULTS HPV DNA was amplified only in one case of squamous cell carcinoma of the 72 Chinese anal cancers and further classified as HPV type 16. Others were all HPV negative. HPV antigen and p53 expression were also detected in this case. Positive stainings with anti-p53 antibody were seen in 61.2% anal cancers. There were no statistically significant differences between anal squamous cell carcinomas and adenocarcinomas and between anal adenocarcinomas and rectal adenocarcinomas. p53 protein expression was observed in the basal cells of squamous epithelium of condyloma acuminatum and morphologically normal squamous epithelium in 2 cases invaded by anal adenocarcinoma.CONCLUSION HPV infection was not associated with these cases of anal cancer. p53 alteration was a common event. Positive p53 immunostaining can not be regarded as a marker for differentiating benign from malignant lesions.

  18. [p53 activation by PI-3K family kinases after DNA double-strand breaks].

    Pernin, D; Uhrhammer, N; Verrelle, P; Bignon, Y J; Bay, J O

    2000-09-01

    p53 plays a central role in the cellular response to DNA double-strand breaks (DSBs), and to DNA damage in general. The protein kinases ATM, ATR and DNA-PK detect DSBs and transmit this information to p53 by phosphorylation. This phosphorylation dissociates p53 from its negative regulator, mdm2. p53 then undergoes further modification and activates transcription of the genes responsible for cell cycle arrest. In certain circumstances, p53 also activates transcription of the genes responsible for apoptosis. The dysfunction of this cascade of events is oncogenic, with P53 itself being the most commonly mutated gene in malignant cells, although mutations in both the DNA damage sensors and cell cycle checkpoint and apoptosis effectors are frequent. A more complete understanding of p53 and the proteins it interacts with may allow the development of new cancer treatments. PMID:11038413

  19. Expression of COX-2, iNOS, p53 and Ki-67 in gastric mucosa-associated lymphoid tissue lymphoma

    Hong-Ling Li; Bing-Zhong Sun; Fu-Cheng Ma

    2004-01-01

    AIM:To assess the expression of cyclooxygenase-2 (COX-2),nitric oxide synthase (iNOS), p53 and Ki-67 in gastric mucosaassociated lymphoid tissue (MALT) lymphoma and clarify the relationship between COX-2 expression and iNOS or p53 expression in these patients.METHODS: The expressions of COX-2, iNOS, p53 and Ki-67 were detected in 32 gastric MALT lymphoma specimens and 10 adjacent mucosal specimens by immunohistochemical Envision method.RESULTS: COX-2 and iNOS expressions were significantly higher in gastric MALT lymphoma tissues than those in adjacent normal tissues. The expression of COX-2 was observed in 22 of 32 cases of MALT lymphoma tissues(68.8%). A positive cytoplasmic immunoreactivity for iNOS was detected in 17 of 31 cases (53.1%). COX-2 expression in gastric MALT lymphoma tissues was positively correlated with iNOS expression (r=0.448, P=0.010) and cell proliferative activity analyzed by Ki-67 labeling index (r=0.410, P=0.020).The expression of COX-2 protein did not correlate with age,sex, stage of disease, lymph node metastasis or differentiation.The accumulation of p53 nuclear phosphoprotein was detected in 19(59.4%) of tumors. p53 protein was expressed in 11 of 23 assessed LG tumors and in 8 of 9 assessed HG tumors.The difference of p53 positivity was found statistically significant between LG and HG cases (P=0.0302). The p53 accumulation correlated with advanced clinical stage (stage Ⅲ+Ⅳ vs stage Ⅰ+Ⅱ, P=-0.017). There was a significant positive correlation between COX-2 expression and p53 accumulation status (r=0.403, P=0.022). The mean PI of Ki-67 in each grade group were 36.0±7.73% in HG and 27.4±9.21% in LG. High-proliferation rate correlated with HG tumors (r=0.419, P=0.017). The correlation coefficient showed a significant positive correlation between PI and COX-2 expression in MALT lymphoma patients (r=0.410,P=0.020).CONCLUSION: COX-2 expresses in the majority of gastric MALT lymphoma tissues and correlates with cellular

  20. Discovery of new low-molecular-weight p53-Mdmx disruptors and their anti-cancer activities.

    Uesato, Shinichi; Matsuura, Yoshihiro; Matsue, Saki; Sumiyoshi, Takaaki; Hirata, Yoshiyuki; Takemoto, Suzuho; Kawaratani, Yasuyuki; Yamai, Yusuke; Ishida, Kyoji; Sasaki, Tsutomu; Enari, Masato

    2016-04-15

    Although several p53-Mdm2-binding disruptors have been identified to date, few studies have been published on p53-Mdmx-interaction inhibitors. In the present study, we demonstrated that o-aminothiophenol derivatives with molecular weights of 200-300 selectively inhibited the p53-Mdmx interaction. S-2-Isobutyramidophenyl 2-methylpropanethioate (K-178) (1c) activated p53, up-regulated the expression of its downstream genes such as p21 and Mdm2, and preferentially inhibited the growth of cancer cells with wild-type p53 over those with mutant p53. Furthermore, we found that the S-isobutyryl-deprotected forms 1b and 3b of 1c and S-2-benzamidophenyl 2-methylpropanethioate (K-181) (3c) preferentially inhibited the p53-Mdmx interaction over the p53-Mdm2 interaction, respectively, by using a Flag-p53 and glutathione S-transferase (GST)-fused protein complex (Mdm2, Mdmx, DAPK1, or PPID). In addition, the interaction of p53 with Mdmx was lost by replacing a sulfur atom with an oxygen atom in 1b and 1c. These results suggest that sulfides such as 1b, 3b, 4b, and 5b interfere with the binding of p53-Mdmx, resulting in the dissociation of the two proteins. Furthermore, the results of oral administration experiments using xenografts in nude mice indicated that 1c reduced the volume of tumor masses to 49.0% and 36.6% that of the control at 100mg/kg and 150mg/kg, respectively, in 40days. PMID:27010502

  1. Rewiring drug-activated p53-regulatory network from suppressing to promoting tumorigenesis

    Wei Song; Jiguang Wang; Ying Yang; Naihe Jing; Xiangsun Zhang; Luonan Chen; Jiarui Wu

    2012-01-01

    Many of oncogenes and tumor suppressor genes have been found to exert variable and even opposing roles in different kinds of tumors or at different stages of cancer development.Here we showed that tumorigenic potential of mouse embryonic carcinoma P19 cells cultured in adherent plates (attached-P19-cells) was suppressed by a chemotherapeutic agent,5-aza-2'-deoxycytidine (ZdCyd),whereas the higher pro-tumorigenicity of P19 cells growing in suspension (detached-P19-cells) was generated by the ZdCyd treatment.Surprisingly,p53 activity was highly up-regulated by ZdCyd in both growing conditions.By our developed computational approaches,we revealed that there was a significant enrichment of apoptotic pathways in the ZdCyd-induced p53-dominant gene-regulatory network in attached P19 cells,whereas the pro-survival genes were significantly enriched in the ZdCyd-induced p53 network in detached P19 cells.The protein-protein interaction network of the ZdCyd-treated detached P19 cells was significantly different from that of ZdCyd-treated attached P19 cells.On the other hand,inhibition of pS3 expression by siRNA suppressed the ZdCyd-induced tumorigenesis of detached P19 cells,suggesting that the ZdCyd-activated p53 plays oncogenic function in detached P19 cells.Taken together,these results indicate a context-dependent role for the ZdCyd-activated p53-dominant network in tumorigenesis.

  2. Prognostic Value of p53 and bcl-2 Expression in Patients Treated with Breast Conservative Therapy

    Kim, Kyubo; Chie, Eui Kyu; Han, Wonshik; Noh, Dong-Young; Park, In Ae; Oh, Do-Youn; Im, Seock-Ah; Kim, Tae-You; Bang, Yung-Jue; Sung W Ha

    2010-01-01

    Prognostic value of p53 and bcl-2 expression on treatment outcome in breast cancer patients has been extensively evaluated, but the results were inconclusive. We evaluated the prognostic significance of these molecular markers in patients treated with breast conserving surgery and radiotherapy. One hundred patients whose immunostaining of p53 and bcl-2 expression was available among 125 patients who underwent radiotherapy after breast conserving surgery and axillary lymph node dissection were...

  3. Regulation of Nucleotide Metabolism by Mutant p53 Contributes to its Gain-of-Function Activities

    Kollareddy, Madhusudhan; Dimitrova, Elizabeth; Vallabhaneni, Krishna C.; Chan, Adriano; Le, Thuc; Chauhan, Krishna M.; Zunamys I. Carrero; Ramakrishnan, Gopalakrishnan; Watabe, Kounosuke; Haupt, Ygal; Haupt, Sue; Pochampally, Radhika; Boss, Gerard R.; Romero, Damian G.; Radu, Caius G.

    2015-01-01

    SUMMARY Mutant p53 (mtp53) is an oncogene that drives cancer cell proliferation. Here we report that mtp53 associates with the promoters of numerous nucleotide metabolism genes (NMG). Mtp53 knockdown reduces NMG expression and substantially depletes nucleotide pools, which attenuates GTP dependent protein (GTPase) activity and cell invasion. Addition of exogenous guanosine or GTP restores the invasiveness of mtp53 knockdown cells, suggesting that mtp53 promotes invasion by increasing GTP. Add...

  4. Modulation of p53 activity by IκBα: Evidence suggesting a common phylogeny between NF-κB and p53 transcription factors

    Gelfand Erwin W

    2005-06-01

    Full Text Available Abstract Background In this work we present evidence that the p53 tumor suppressor protein and NF-κB transcription factors could be related through common descent from a family of ancestral transcription factors regulating cellular proliferation and apoptosis. P53 is a homotetrameric transcription factor known to interact with the ankyrin protein 53BP2 (a fragment of the ASPP2 protein. NF-κB is also regulated by ankyrin proteins, the prototype of which is the IκB family. The DNA binding sequences of the two transcription factors are similar, sharing 8 out of 10 nucleotides. Interactions between the two proteins, both direct and indirect, have been noted previously and the two proteins play central roles in the control of proliferation and apoptosis. Results Using previously published structure data, we noted a significant degree of structural alignment between p53 and NF-κB p65. We also determined that IκBα and p53 bind in vitro through a specific interaction in part involving the DNA binding region of p53, or a region proximal to it, and the amino terminus of IκBα independently or cooperatively with the ankyrin 3 domain of IκBα In cotransfection experiments, κBα could significantly inhibit the transcriptional activity of p53. Inhibition of p53-mediated transcription was increased by deletion of the ankyrin 2, 4, or 5 domains of IκBα Co-precipitation experiments using the stably transfected ankyrin 5 deletion mutant of κBα and endogenous wild-type p53 further support the hypothesis that p53 and IκBα can physically interact in vivo. Conclusion The aggregate results obtained using bacterially produced IκBα and p53 as well as reticulocyte lysate produced proteins suggest a correlation between in vitro co-precipitation in at least one of the systems and in vivo p53 inhibitory activity. These observations argue for a mechanism involving direct binding of IκBα to p53 in the inhibition of p53 transcriptional activity, analogous to

  5. EXPRESSION OF FRAGILE HISTIDINE TRIAD AND P53 IN NON-SMALL CELL LUNG CANCER

    HOU Xing-hua; ZHANG Dao-rong

    2006-01-01

    Objective: To investigate the expression of fragile histidine triad (FHIT) and p53 protein in non-small cell lung cancer (NSCLC) and explore the relationship between their expressions and the clinicopathological features. Methods: FHIT protein and p53 protein were detected by immunohistochemistry in 76 cases of NSCLCs and matched normal lung tissues. Results:Fifty-one cases (67.1%) showed negative expression of FHIT (apparent reduction or loss) and thirty-seven cases (48.7%)showed p53 positive expression (overexpression). The difference was significant (P=0.04). However, there was no significant difference in FHIT expression between the p53-positive group and the p53-negative group (64.9% versus 69.2%, P=0.686).The negative rate of FHIT protein expression was higher in squamous cell carcinoma than in adenocarcinoma, in moderately and poorly differentiated carcinoma than in well-differentiated carcinoma, and in cases with smoking history than in cases without smoking history (P<0.05). There was no relationship between FHIT expression and clinical stage or lymph node metastasis. The negative FHIT expression was not an independent predictor of overall survival (P=0.338). Conclusion: The frequency of negative expression of FHIT protein is higher than that of positive expression of p53 in NSCLCs. The negative expression of FHIT is independent of the expression of p53. The change of expression of FHIT may play a role in the smoking related lung tumorigenesis while it may have no relationship with the progress of NSCLC or prognosis of the patients.

  6. The expression of GST isoenzymes and p53 in non-small cell lung cancer.

    MĂźzeyyen Ozhavzali

    2010-06-01

    Full Text Available This study investigated the immunohistochemical staining characteristics of glutathione-S-transferase alpha, pi, mu, theta and p53 in non-small cell lung carcinoma and normal lung tissue from 50 patients. The relationships between expressions of the Glutathione-S-transferase isoenzymes and some clinicopathological features were also examined. Expression of glutathione-S-transferase pi, mu, alpha, theta and p53 was assessed by immunohistochemistry for primary lung carcinomas of 50 patients from the Sanitarium Education and Research Hospital, Ankara lung cancer collection. The relationships between expression of the glutathione-S-transferase isoenzymes, p53 in normal and tumor tissue by Student T test and the clinicopathological data were also examined by Spearman Rank tests. When the normal and tumor tissue of these cases were compared according to their staining intensity and percentage of positive staining, glutathione-S-transferase alpha, pi, mu, theta expressions in tumor cells was significantly higher than normal cells (p<0.05. There was no significant difference in the expression of p53 between normal and tumor cells (p>0.05. When the immunohistochemical results of glutathione-S-transferase isoenzymes and p53 were correlated with the clinical parameters, there were no significant associations between glutathione-S-transferases and p53 expressions and tumor stage, tumor grade and smoking status (p>0.05.

  7. Correlation Between Akt and p53 Protein Expression and Chemoradiotherapy Response in Cervical Cancer Patients

    IIN KURNIA

    2014-12-01

    Full Text Available Akt is a protein that is associated with cell proliferation and is expressed at high levels in cancer cells. Some research indicates it may play a role in increasing the resistance of cancer cells to chemotherapy treatment. P53 is a tumor suppressor protein that influences the cell cycle and apoptosis. The purpose of this study was to examine the relationship between the expression of Akt and p53 in cancerous tissue before chemoradiation treatment, and the clinical response to treatment of cervical cancer patients. Twenty microscopic tissue samples were taken from cervical cancer biopsies obtained from patients before cancer treatment. The tissue samples were stained with p53 and Akt antibodies via immunohistochemistry technique, to measure expression of both proteins. After completion of chemoradiotherapy, patients’ clinical response to treatment was determined using the pelvic control method. Our results revealed no correlation between expression of Akt and p53 index (P = 0.74 as well as between p53 Index and chemoradiotherapy clinical response (P=0.29. There was significant correlation between expression of Akt and cervical cancer chemoradiotherapy response (P = 0.03. There was no correlation found between p53 index and chemoradiotherapy clinical response (P = 0.29. High expression of Akt may related with high cell proliferation and resistance to chemoradiotherapy.

  8. Expressions of Maspin, P53 and Skp2 in Colorectal Tumors and Their Clinicopathological Significance

    Jiang-tao Ni; Yong-fen Yi; Hai-peng Shi

    2009-01-01

    Objective: To investigate the role of maspin, p53 and Skp2 expressions in the progression of colorectal tumors, and their clinicopathological significance.Methods: The expressions of maspin, p53 and Skp2 in colorectal adenocarcinoma (n=50), adenoma (n=20) and normal tissue (n=20) were detected by immunohistochemistry and compared with the clinicopathological tumor parameters. The relationship among maspin, p53 and Skp2 expression was also analyzed in colorectal tumors. The reverse transcriptase PCR was carried out to detect the level of maspin mRNA from 31 colorectal adenocarcinoma and 10 normal control tissues.Results: Of 50 cases of colorectal adenocarcinoma, the positive expression rates for maspin, p53 and Skp2 in colorectal adenocarcinoma were 62% (31 of 50 cases), 50% (25 of 50 cases), 48%( 24 of 50 cases), respectively; The positive expression rates for maspin, p53 and Skp2 in adenoma were 90%, 5%, 5%, respectively; The positive expression rates for maspin, p53 and Skp2 in normal control were 95%, 5%, 5%, respectively. Maspin expression was much lower in colorectal adenocarcinoma than in adenoma and normal tissues (both P<0.05). Maspin expression showed a negative association with lymphatic metastasis and higher Dukes' stage (both P<0.05). Expression of maspin protein was negatively correlated with p53 expression (r =-0.536,P<0.01, in adenocarcinoma; r=-0.668,P<0.01,in adenoma). However, there was no significant correlation between expression of p53 and Skp2 (r=0.000, P>0.05, in adenocarcinoma; r=-0.053,P>0.05, in adenoma).Conclusion: Maspin might play an important role in tumorigenesis and progression (especially in lymph node metastasis) of colorectal adenocarcinoma. Maspin expression was inversely correlated with mutant p53 expression in colorectal tumors, which suggested that maspin expression was regulated by the p53 pathway. Skp2 might serve as an independent factor which participated in multistage process of colorectal carcinogenesis.

  9. The expression and significance of hTERT and P53 in thyroid carcinoma

    2010-01-01

    Objective To determine the expression of human telomerase reverse transcriptase (hTERT) and P53 in thyroid carcinoma and its relationship with development and prognosis of the carcinoma. Methods Totally 90 cases of thyroid specimens (60 thyroid carcinomas,10 thyroid adenomas,10 goitres and 10 normal thyroid tissues) were studied by SP immunohistochemical method. Results Positive immunoreactivity of hTERT and P53 was higher in thyroid carcinoma (P<0.05). The positive rates of hTERT and P53 were higher in und...

  10. High-level expression of human tumour suppressor P53 in the methylotrophic yeast: Pichia pastoris.

    Abdelmoula-Souissi, Salma; Rekik, Leila; Gargouri, Ali; Mokdad-Gargouri, Raja

    2007-08-01

    The human tumour suppressor P53 is a key protein involved in tumour suppression. P53 acts as a "guardian of genome" by regulating many target genes involved in cell cycle regulation, DNA repair and apoptosis. We report the P53 expression by the methylotrophic yeast Pichia pastoris using the methanol inducible AOX1 promoter. We have produced the rP53 in intracellular form as well as secreted using the Saccharomyces cerevisiae alpha-mating factor prepro-leader sequence in two genetic contexts of Pichia, Mut(s) and Mut(+). The intracellular P53 was successfully produced by Mut(s) (KM71) as well as Mut(+) (X33) strains, however, the secreted form was mainly observed in the Mut(s) strain, despite a higher number of p53 copies integrated in the Mut(+) strain. Interestingly, in Mut(s) phenotype, the medium pH influences markedly the rP53 production since it was higher at pH 7 than 6. PMID:17482479

  11. Loss of Maspin Expression in Bladder Cancer: Its Relationship with p53 and Clinico pathological Parameters

    Maspin (mammary serine protease inhibitor) is a member of the serpin super family of protease inhibitors and is known to have tumor-suppressor function in breast and prostate cancers, acting at the level of tumor invasion and metastasis. However, there have been no published data regarding the role of Maspin in squamous cell carcinoma (SCC) and transitional cell carcinoma (TCC) of urinary bladder. Patients and Methods: We have evaluated the immunohistochemical expression of Maspin and p53 in a series of 134 bladder cancer patients (56 SCC and 78 TCC) and the interrelationship between Clinico pathological features and Maspin and p53 expression. Results: There was positive Maspin expression in 53.7% in all cases. In TCC, expression was found in 48/78 cases (61.5%). High Maspin expression was found in low grade (p<0.001) and advanced stage (p=0.02). In SCC, expression was found in 24/56 (42.8%). There was a statistically significant association between lost Maspin expression and grading (p=0.001). No correlation was found between Maspin expression and other Clinico pathological parameters including gender, clinical stage and Bilharzial infestation. These results indicated that Maspin expression might predict a better prognosis for bladder carcinoma. Also Maspin probably could play a role in tumor progression. p53 was positive in 70 cases (52.2%) of all patients evaluated. In TCC, it was positive in 36/78 cases (46.1%) and correlated with high grade (p=0.01) and advanced stage (p=0.01). In SCC, it was positive in 34/56 cases (60.7%). There was a statistically significant association between p53 expression and high grade (p=0.01) and advanced stage (p=0.01). There was an inverse correlation between the Maspin and p53 expression in TCC and SCC of bladder cancer. We found no significant association between both Maspin and p53 expression and bilharziasis in TCC and SCC; this indicated that Maspin and p53 expression could be prognostic factors in both bilharzial and non

  12. Promoter methylation of IGFBP-3 and p53 expression in ovarian endometrioid carcinoma

    Huang Su-Cheng; Yang Hui-Wen; Chan Michael WY; Lin Ching-Wei; Torng Pao-Ling; Lin Chin-Tarng

    2009-01-01

    Abstract Background Insulin-like growth factor binding protein (IGFBP-3) is an antiproliferative, pro-apoptotic and invasion suppressor protein which is transcriptionally regulated by p53. Promoter methylation has been linked to gene silencing and cancer progression. We studied the correlation between IGFBP-3 and p53 expression as well as IGFBP-3 promoter methylation in ovarian endometrioid carcinoma (OEC) by immunohistochemical staining and quantitative methylation-specific PCR (qMSP). Addit...

  13. Exercise Activates p53 and Negatively Regulates IGF-1 Pathway in Epidermis within a Skin Cancer Model

    Yu, Miao; King, Brenee; Ewert, Emily; Su, Xiaoyu; Mardiyati, Nur; Zhao, Zhihui; Wang, Weiqun

    2016-01-01

    Exercise has been previously reported to lower cancer risk through reducing circulating IGF-1 and IGF-1-dependent signaling in a mouse skin cancer model. This study aims to investigate the underlying mechanisms by which exercise may down-regulate the IGF-1 pathway via p53 and p53-related regulators in the skin epidermis. Female SENCAR mice were pair-fed an AIN-93 diet with or without 10-week treadmill exercise at 20 m/min, 60 min/day and 5 days/week. Animals were topically treated with TPA 2 hours before sacrifice and the target proteins in the epidermis were analyzed by both immunohistochemistry and Western blot. Under TPA or vehicle treatment, MDM2 expression was significantly reduced in exercised mice when compared with sedentary control. Meanwhile, p53 was significantly elevated. In addition, p53-transcriptioned proteins, i.e., p21, IGFBP-3, and PTEN, increased in response to exercise. There was a synergy effect between exercise and TPA on the decreased MDM2 and increased p53, but not p53-transcripted proteins. Taken together, exercise appeared to activate p53, resulting in enhanced expression of p21, IGFBP-3, and PTEN that might induce a negative regulation of IGF-1 pathway and thus contribute to the observed cancer prevention by exercise in this skin cancer model. PMID:27509024

  14. p53 Nuclear Accumulation and Bcl-2 Expression in Contiguous Adenomatous Components of Colorectal Adenocarcinomas Predict Aggressive Tumor Behavior

    Shanmugam, Chandrakumar; Katkoori, Venkat R.; Jhala, Nirag C.; Grizzle, William E.; Gene P Siegal; Manne, Upender

    2008-01-01

    For subsets of colorectal adenocarcinoma (CRC) patients, nuclear accumulation of p53 (p53nac) and Bcl-2 expression are prognostic indicators. To understand their role in the progression of CRC we evaluated 90 CRCs and their contiguous adenomatous components (CAdCs) for immunohistochemical expression of these markers. In general, p53nac and Bcl-2 expression was significantly increased when comparing normal colonic epithelia to CAdCs and CRCs. Thirteen (14%) CAdCs that demonstrated p53nac conti...

  15. Telomerase in relation to expression of p53, c-Myc and estrogen receptor in ovarian tumours

    Wisman, GBA; Hollema, H; Helder, MN; Knol, AJ; Van Der Meer, GT; Krans, M; De Jong, S; De Vries, EGE; Van Der Zee, AGJ

    2003-01-01

    Telomerase activity and its subunits (hTERC, hTERT mRNA) were evaluated in ovarian tumours in relation to the expression of p53, c-Myc and estrogen receptor (ER). Furthermore, relations between telomerase activity, hTERC and hTERT with known clinicopathologic prognostic factors and survival in patie

  16. The expression of p53 protein in patients with multiple myeloma

    Marković Olivera

    2007-01-01

    Full Text Available Introduction: Although mutations of p53 are one of the most often acquired genetic changes in malignant tumors, these mutations are rare events in patients with newly diagnosed multiple myeloma (MM. Moreover, there are a few literature data about clinical significance of p53 overexpression in multiple myeloma. Objective The aim of our study was to evaluate the clinical significance of p53 immunoexpression in multiple myeloma. Method A total of 58 patients with newly diagnosed MM (26 females and 32 males, mean age 62 years were enrolled in the study. The diagnosis of MM was made according to criteria of Chronic Leukemia-Myeloma Task Force. Clinical staging was done according to Durie and Salmon classification (4 patients had disease stage I, 15 patients stage II and 39 patients stage III. The histological grade and histological stage were determined according to predominant plasma cell morphology and volume of myeloma infiltration, respectively. Standard immunohistochemical analysis with p53 antibody in B5-fixed and paraffin- embedded bone marrow specimens was used to evaluate the expression of p53 in myeloma cells. The specimens were considered positive when ≥5% of plasma cells exhibited clear nuclear positivity. Results Out of 58 patients, p53 expression was detected in 9 (15.52%. No significant correlation was found between p53 expression and clinical stage (I+II vs. III, Я2-microglobulin level (≤6 mg/L vs. >6mg/L, histological grade (I vs. II+III, histological stage (<20% vs. 21-50% vs. >50% and the extent of osteolytic lesions (≤3 vs. >3 lesions. Median survival of patients with p53 immunoreactivity in =>5% of plasma cells was 10 months, whilst median survival of patients with p53 immunoreactivity in <5% of plasma cells was 36 months. However, such difference was not significant (p=0.2. Conclusion The frequency of p53 immunoexpression in our group of newly diagnosed MM was relatively low. Although p53 immunoexpression was not

  17. p53-mediated activation of the mitochondrial protease HtrA2/Omi prevents cell invasion

    Yamauchi, Shota; Hou, Yan Yan; Guo, Alvin Kunyao; Hirata, Hiroaki; Nakajima, Wataru; Yip, Ai Kia; Yu, Cheng-Han; Harada, Ichiro; Chiam, Keng-Hwee; Sawada, Yasuhiro; Tanaka, Nobuyuki; Kawauchi, Keiko

    2014-01-01

    Oncogenic Ras induces cell transformation and promotes an invasive phenotype. The tumor suppressor p53 has a suppressive role in Rasdriven invasion. However, its mechanism remains poorly understood. Here we show that p53 induces activation of the mitochondrial protease high-temperature requirement A2 (HtrA2; also known as Omi) and prevents Ras-driven invasion by modulating the actin cytoskeleton. Oncogenic Ras increases accumulation of p53 in the cytoplasm, which promotes the translocation of...

  18. New insights into the anticancer activity of carnosol: p53 reactivation in the U87MG human glioblastoma cell line.

    Giacomelli, Chiara; Natali, Letizia; Trincavelli, Maria Letizia; Daniele, Simona; Bertoli, Alessandra; Flamini, Guido; Braca, Alessandra; Martini, Claudia

    2016-05-01

    Glioblastoma multiforme (GBM) is an aggressive brain tumour with high resistance to radio- and chemotherapy. As such, increasing attention has focused on developing new therapeutic strategies to improve treatment responses. Recently, attention has been shifted to natural compounds that are able to halt tumour development. Among them, carnosol (CAR), a phenolic diterpene present in rosemary, has become a promising molecule that is able to prevent certain types of solid cancer. However, no data are available on the effects of CAR in GBM. Here, CAR activity decreased the proliferation of different human glioblastoma cell lines, particularly cells that express wild type p53. The p53 pathway is involved in the control of apoptosis and is often impaired in GBM. Notably, CAR, through the dissociation of p53 from its endogenous inhibitor MDM2, was able to increase the intracellular p53 levels in GBM cells. Accordingly, functional reactivation of p53 was demonstrated by the stimulation of p53 target genes' transcription, the induction of apoptosis and cell cycle blockade. Most importantly, CAR produced synergistic effects with temozolomide (TMZ) and reduced the restoration of the tumour cells' proliferation after drug removal. Thus, for the first time, these data highlighted the potential use of the diterpene in the sensitization of GBM cells to chemotherapy through a direct re-activation of p53 pathway. Furthermore, progress has been made in delineating the biochemical mechanisms underlying the pro-apoptotic effects of this molecule. PMID:26939786

  19. Ensemble-based computational approach discriminates functional activity of p53 cancer and rescue mutants.

    Özlem Demir

    2011-10-01

    Full Text Available The tumor suppressor protein p53 can lose its function upon single-point missense mutations in the core DNA-binding domain ("cancer mutants". Activity can be restored by second-site suppressor mutations ("rescue mutants". This paper relates the functional activity of p53 cancer and rescue mutants to their overall molecular dynamics (MD, without focusing on local structural details. A novel global measure of protein flexibility for the p53 core DNA-binding domain, the number of clusters at a certain RMSD cutoff, was computed by clustering over 0.7 µs of explicitly solvated all-atom MD simulations. For wild-type p53 and a sample of p53 cancer or rescue mutants, the number of clusters was a good predictor of in vivo p53 functional activity in cell-based assays. This number-of-clusters (NOC metric was strongly correlated (r(2 = 0.77 with reported values of experimentally measured ΔΔG protein thermodynamic stability. Interpreting the number of clusters as a measure of protein flexibility: (i p53 cancer mutants were more flexible than wild-type protein, (ii second-site rescue mutations decreased the flexibility of cancer mutants, and (iii negative controls of non-rescue second-site mutants did not. This new method reflects the overall stability of the p53 core domain and can discriminate which second-site mutations restore activity to p53 cancer mutants.

  20. Modulation of p53 expression using antisense oligonucleotides complementary to the 5'-terminal region of p53 mRNA in vitro and in the living cells.

    Agnieszka Gorska

    Full Text Available The p53 protein is a key player in cell response to stress events and cancer prevention. However, up-regulation of p53 that occurs during radiotherapy of some tumours results in radio-resistance of targeted cells. Recently, antisense oligonucleotides have been used to reduce the p53 level in tumour cells which facilitates their radiation-induced apoptosis. Here we describe the rational design of antisense oligomers directed against the 5'-terminal region of p53 mRNA aimed to inhibit the synthesis of p53 protein and its ΔNp53 isoform. A comprehensive analysis of the sites accessible to oligomer hybridization in this mRNA region was performed. Subsequently, translation efficiency from the initiation codons for both proteins in the presence of selected oligomers was determined in rabbit reticulocyte lysate and in MCF-7 cells. The antisense oligomers with 2'-OMe and LNA modifications were used to study the mechanism of their impact on translation. It turned out that the remaining RNase H activity of the lysate contributed to modulation of protein synthesis efficiency which was observed in the presence of antisense oligomers. A possibility of changing the ratio of the newly synthetized p53 and ΔNp53 in a controlled manner was revealed which is potentially very attractive considering the relationship between the functioning of these two proteins. Selected antisense oligonucleotides which were designed based on accessibility mapping of the 5'-terminal region of p53 mRNA were able to significantly reduce the level of p53 protein in MCF-7 cells. One of these oligomers might be used in the future as a support treatment in anticancer therapy.

  1. Mad2 and p53 expression profiles in colorectal cancer and its clinical significance

    Gang-Qiang Li; Hao Li; Hong-Fu Zhang

    2003-01-01

    AIM: To investigate the expression of tumor suppressor gene p53 and spindle checkpoint gene Mad2, and to demonstrate their expression difference in colorectal cancer and normal mucosa and to evaluate its clinical significance.METHODS: Westemn blot and immunohistochemistry methods were used to analyze the expression of Mad2 in colorectal cancer and its corresponding normal mucosa. The expression of p53 was detected by immunohistochemistry method in colorectal cancer and its corresponding normal mucosa.RESULTS: Mad2 was significantly overexpressed in colorectal cancer compared with corresponding normal mucosa (P<0.001), and it was not related to the differentiation of adenocarcinoma and other dinical factors (P>0.05).The ratio of Mad2 protein in cancer tissue (C) to that in its normal mucosa tissue (N) was higher than 2, which was more frequently observed in patients with lymph gland metastasis (P<0.05). p53 protein expression was not observed in normal mucosa. The rate of p53 positive expression in adenocarcinomas was 52.6%. There was a significant difference between adenocarcinomas and normal mucosa(P<0.001), which was not related to the differentiation degree of adenocarcinoma and other clinical factors (P>0.05).CONCLUSION: Defect of spindle checkpoint gene Mad2and mutation of p53 gene are involved mainly in colorectal carcinogenesis and C/N>2 is associated with prognosis of colorectal cancer.

  2. Acetylation of p53 at Lysine 373/382 by the Histone Deacetylase Inhibitor Depsipeptide Induces Expression of p21Waf1/Cip1

    Zhao, Ying; Lu, Shaoli; Wu, Lipeng; Chai, Guolin; Wang, Haiying; Chen, Yingqi; Sun, Jia; Yu, Yu; Zhou, Wen; Zheng, Quanhui; Wu, Mian; Otterson, Gregory A.; Zhu, Wei-Guo

    2006-01-01

    Generally, histone deacetylase (HDAC) inhibitor-induced p21Waf1/Cip1 expression is thought to be p53 independent. Here we found that an inhibitor of HDAC, depsipeptide (FR901228), but not trichostatin A (TSA), induces p21Waf1/Cip1 expression through both p53 and Sp1/Sp3 pathways in A549 cells (which retain wild-type p53). This is demonstrated by measuring relative luciferase activities of p21 promoter constructs with p53 or Sp1 binding site mutagenesis and was further confirmed by transfectio...

  3. ATM and p53 regulate FOXM1 expression via E2F in breast cancer epirubicin treatment and resistance

    Millour, Julie; de Olano, Natalia; Horimoto, Yoshiya; Monteiro, Lara J.; Langer, Julia K.; Aligue, Rosa; Hajji, Nabil; Lam, Eric W.-F.

    2011-01-01

    In this report we investigated the role and regulation of FOXM1 in breast cancer and epirubicin resistance. We generated epirubicin resistant MCF-7 breast carcinoma (MCF-7-EPIR) cells and found FOXM1 protein levels to be higher in MCF-7-EPIR compared to MCF-7 cells, and that FOXM1 expression is down-regulated by epirubicin in MCF-7 but not in MCF-7-EPIR cells. We also established that there is a loss of p53 function in MCF-7-EPIR cells and that epirubicin represses FOXM1 expression at transcription and gene promoter levels through activation of p53 and repression of E2F activity in MCF-7 cells. Using p53-/- MEFs, we showed that p53 is important for epirubicin sensitivity. Moreover, transient promoter transfection assays demonstrated that epirubicin and its cellular effectors p53 and E2F1 modulate FOXM1 transcription through an E2F-binding site located within the proximal promoter region. Chromatin immunoprecipitation analysis also revealed that epirubicin treatment increases pRB and decreases E2F1 recruitment to the FOXM1 promoter region containing the E2F-site. We also found Ataxia-telangiectasia mutated (ATM) protein and mRNA to be overexpressed in the resistant MCF-7-EPIR cells compared to MCF-7 cells and that epirubicin can activate ATM to promote E2F activity and FOXM1 expression. Furthermore, inhibition of ATM in U2OS cells with caffeine or depletion of ATM in MCF-7-EPIR with siRNAs can re-sensitise these resistant cells to epirubicin, resulting in down-regulation of E2F1 and FOXM1 expression and cell death. In summary, our data show that ATM and p53 coordinately regulate FOXM1 via E2F to modulate epirubicin response and resistance in breast cancer. PMID:21518729

  4. Expression of Fbxo7 in haematopoietic progenitor cells cooperates with p53 loss to promote lymphomagenesis.

    Mikhail Lomonosov

    Full Text Available Fbxo7 is an unusual F box protein that augments D-type cyclin complex formation with Cdk6, but not Cdk4 or Cdk2, and its over-expression has been demonstrated to transform immortalised fibroblasts in a Cdk6-dependent manner. Here we present new evidence in vitro and in vivo on the oncogenic potential of this regulatory protein in primary haematopoietic stem and progenitor cells (HSPCs. Increasing Fbxo7 expression in HSPCs suppressed their colony forming ability in vitro, specifically decreasing CD11b (Mac1 expression, and these effects were dependent on an intact p53 pathway. Furthermore, increased Fbxo7 levels enhanced the proliferative capacity of p53 null HSPCs when they were grown in reduced concentrations of stem cell factor. Finally, irradiated mice reconstituted with p53 null, but not wild-type, HSPCs expressing Fbxo7 showed a statistically significant increase in the incidence of T cell lymphoma in vivo. These data argue that Fbxo7 negatively regulates the proliferation and differentiation of HSPCs in a p53-dependent manner, and that in the absence of p53, Fbxo7 expression can promote T cell lymphomagenesis.

  5. Updates on p53: modulation of p53 degradation as a therapeutic approach

    Dey, A; Verma, C S; LANE, D. P.

    2008-01-01

    The p53 pathway is aberrant in most human tumours with over 50% expressing mutant p53 proteins. The pathway is critically controlled by protein degradation. Here, we discuss the latest developments in the search for small molecules that can modulate p53 pathway protein stability and restore p53 activity for cancer therapy.

  6. A naturally occurring 4-bp deletion in the intron 4 of p53 creates a spectrum of novel p53 isoforms with anti-apoptosis function

    Hui SHI; Tao, Ting; Huang, Delai; Ou, Zhao; Chen, Jun; Peng, Jinrong

    2014-01-01

    p53 functions as a tumor suppressor by transcriptionally regulating the expression of genes involved in controlling cell proliferation or apoptosis. p53 and its isoform Δ133p53/Δ113p53 form a negative regulation loop in that p53 activates the expression of Δ133p53/Δ113p53 while Δ133p53/Δ113p53 specifically antagonizes p53 apoptotic activity. This pathway is especially important to safeguard the process of embryogenesis because sudden activation of p53 by DNA damage signals or developmental st...

  7. Pharmacological activation of wild-type p53 in the therapy of leukemia.

    Kojima, Kensuke; Ishizawa, Jo; Andreeff, Michael

    2016-09-01

    The tumor suppressor p53 is inactivated by mutations in the majority of human solid tumors. Conversely, p53 mutations are rare in leukemias and are only observed in a small fraction of the patient population, predominately in patients with complex karyotype acute myeloid leukemia or hypodiploid acute lymphoblastic leukemia. However, the loss of p53 function in leukemic cells is often caused by abnormalities in p53-regulatory proteins, including overexpression of MDM2/MDMX, deletion of CDKN2A/ARF, and alterations in ATM. For example, MDM2 inhibits p53-mediated transcription, promotes its nuclear export, and induces proteasome-dependent degradation. The MDM2 homolog MDMX is another direct regulator of p53 that inhibits p53-mediated transcription. Several small-molecule inhibitors and stapled peptides targeting MDM2 and MDMX have been developed and have recently entered clinical trials. The clinical trial results of the first clinically used MDM2 inhibitor, RG7112, illustrated promising p53 activation and apoptosis induction in leukemia cells as proof of concept. Side effects of RG7112 were most prominent in suppression of thrombopoiesis and gastrointestinal symptoms in leukemia patients. Predictive biomarkers for response to MDM2 inhibitors have been proposed, but they require further validation both in vitro and in vivo so that the accumulated knowledge concerning pathological p53 dysregulation in leukemia and novel molecular-targeted strategies to overcome this dysregulation can be translated safely and efficiently into novel clinical therapeutics. PMID:27327543

  8. hSSB1 regulates both the stability and the transcriptional activity of p53

    Shuangbing Xu; Yuanzhong Wu; Qiong Chen; Jingying Cao; Kaishun Hu; Jianjun Tang; Yi Sang

    2013-01-01

    The tumor suppressor p53 is essential for several cellular processes that are involved in the response to diverse genotoxic stress,including cell cycle arrest,DNA repair,apoptosis and senescence.Studies of the regulation of p53 have mostly focused on its stability and transactivation; however,new regulatory molecules for p53 have also been frequently identified.Here,we report that human ssDNA binding protein SSB1 (hSSB1),a novel DNA damageassociated protein,can interact with p53 and protect p53 from ubiquitin-mediated degradation.Furthermore,hSSB1 also associates with the acetyltransferase p300 and is required for efficient transcriptional activation of the p53 target gene p21 by affecting the acetylation of p53 at lysine382.Functionally,the hSSB1 knockdown-induced abrogation of the G2/M checkpoint is partially dependent on p53 or p300.Collectively,our results indicate that hSSB1 may regulate DNA damage checkpoints by positively modulating p53 and its downstream target p21.

  9. Expression and significance of p53 and mdm2 in patients with leukoplakia cancer

    Juan-Juan Cui; Xiao-Lan Han; Wei-Min Wang

    2013-01-01

    Objective:To study the relationship of the expressions of p53 and mdm2 in leukoplakia cancer. Methods:RT-PCR was used to detect the mRNA of p53, mdm2 in patients with leukoplakia cancer.The frequencies of p53, mdm2 in peripheral blood were detected by flow cytometric analysis.Results:The expression of p53mRNA in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were7.7%,27.3%,33.3%,56.8%, respectively. The frequencies of p53 in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were(0.3±0.1)%,(1.6±0.9)%,(1.9±1.1)%,(3.4±1.8)%.The expression of mdm2 mRNA in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were0.0%,6.8%,11.1%,37.8%, respectively.The frequencies ofmdm2 in normal oral mucosa, simple oral leukoplakia, no-simple oral leukoplakia and leukoplakia cancer were(0.1±0.1)%,(0.8±0.6)%,(1.2±0.8)%,(1.2±0.8)%.There was a positively correlation between p53 mRNA and mdm2 mRNA.Conclusions:The positive rate of p53 and mdm2 cells in the peripheral blood increases in patients with leukoplakia cancer tissue and has positive correlation with the severity of leukoplakia cancer.

  10. Bcl-2 protein expression is associated with p27 and p53 protein expressions and MIB-1 counts in breast cancer

    Nishizaki Takashi

    2006-07-01

    Full Text Available Abstract Background Recent experimental studies have shown that Bcl-2, which has been established as a key player in the control of apoptosis, plays a role in regulating the cell cycle and proliferation. The aim of this study was to investigate the relationship between Bcl-2 and p27 protein expression, p53 protein expression and the proliferation activity as defined by the MIB-1 counts. The prognostic implication of Bcl-2 protein expression in relation to p27 and p53 protein expressions and MIB-1 counts for breast cancer was also evaluated. Methods The immunohistochemical expression of Bcl-2 protein was evaluated in a series of 249 invasive ductal carcinomas of the breast, in which p27 and p53 protein expressions and MIB-1 counts had been determined previously. Results The Bcl-2 protein expression was found to be decreased in 105 (42% cases. A decreased Bcl-2 protein expression was significantly correlated with a nuclear grade of III, a negative estrogen receptor, a decreased p27 protein expression, a positive p53 protein expression, positive MIB-1 counts and a positive HER2 protein expression. The incidence of a nuclear grade of III and positive MIB-1 counts increased as the number of abnormal findings of Bcl-2, p27 and p53 protein expressions increased. A univariate analysis indicated a decreased Bcl-2 protein expression to be significantly (p = 0.0089 associated with a worse disease free survival (DFS, while a multivariate analysis indicated the lymph node status and MIB-1 counts to be independently significant prognostic factors for the DFS. Conclusion The Bcl-2 protein expression has a close correlation with p27 and p53 protein expressions and the proliferation activity determined by MIB-1 counts in invasive ductal carcinoma of the breast. The prognostic value of Bcl-2 as well as p27 and p53 protein expressions was dependent on the proliferation activity in breast cancer.

  11. Human T-cell leukemia virus type-1-encoded protein HBZ represses p53 function by inhibiting the acetyltransferase activity of p300/CBP and HBO1

    Hoang, Kimson; Ankney, John A.; Nguyen, Stephanie T.; Rushing, Amanda W.; Polakowski, Nicholas; Miotto, Benoit; Lemasson, Isabelle

    2016-01-01

    Adult T-cell leukemia (ATL) is an often fatal malignancy caused by infection with the complex retrovirus, human T-cell Leukemia Virus, type 1 (HTLV-1). In ATL patient samples, the tumor suppressor, p53, is infrequently mutated; however, it has been shown to be inactivated by the viral protein, Tax. Here, we show that another HTLV-1 protein, HBZ, represses p53 activity. In HCT116 p53+/+ cells treated with the DNA-damaging agent, etoposide, HBZ reduced p53-mediated activation of p21/CDKN1A and GADD45A expression, which was associated with a delay in G2 phase-arrest. These effects were attributed to direct inhibition of the histone acetyltransferase (HAT) activity of p300/CBP by HBZ, causing a reduction in p53 acetylation, which has be linked to decreased p53 activity. In addition, HBZ bound to, and inhibited the HAT activity of HBO1. Although HBO1 did not acetylate p53, it acted as a coactivator for p53 at the p21/CDKN1A promoter. Therefore, through interactions with two separate HAT proteins, HBZ impairs the ability of p53 to activate transcription. This mechanism may explain how p53 activity is restricted in ATL cells that do not express Tax due to modifications of the HTLV-1 provirus, which accounts for a majority of patient samples. PMID:26625199

  12. Comparative analysis of P16 and P53 expression in uterine malignant mixed mullerian tumors.

    Buza, Natalia; Tavassoli, Fattaneh A

    2009-11-01

    Recent studies have shown that, in addition to cervical carcinomas, a substantial proportion of endometrial adenocarcinomas are also immunoreactive with p16. The expression of p16 in uterine malignant mixed mullerian tumors (MMMTs), in contrast, has not yet been analyzed in a large series. To our knowledge, we present the first study assessing p16 expression in both components of MMMTs. We performed p16 and p53 immunostains on 30 cases of uterine MMMTs. Both the epithelial and mesenchymal components were subclassified; p16 and p53 immunoreactions were assessed using a semiquantitative scoring system. p16 overexpression was noted in the carcinomatous component in 96.7% (29/30), and in the sarcomatous component in 86.7% (26/30) of cases. In comparison, p53 immunoreactivity was present in the carcinomatous component in 76.7% (23/30), and in the sarcomatous component in 83.3% (25/30) of cases. p16 immunoreactivity was more intense and diffuse than p53 in 40% of type I, 30% of type II carcinomas, and 27% of sarcomatous components. There was no significant difference in p16 or p53 immunoreactivity between the homologous and heterologous sarcomas. The concordance rates for p16 and p53 immunoreactivity between the 2 components were 83% and 90%, respectively. We conclude that p16 immunostain is positive in the vast majority of uterine MMMTs with no significant difference in staining between the 2 components. Compared with p53, p16 immunoreactivity is significantly more intense and diffuse in both components. Our findings indicate that alterations in the p16-Rb pathway play an important role in the pathogenesis of uterine MMMTs. PMID:19851197

  13.  Immunohistochemical Expression of ki-67 and p53 in Colorectal Adenomas: A Clinicopathological Study

    Hussam Hasson Ali

    2011-07-01

    Full Text Available  Objectives: To evaluate the significance of P53 and Ki-67 expression as immunohistochemical markers in early detection of premalignant changes in different types of colorectal adenomas. Also, to correlate immunohistochemical expression of the two markers with different clinicopathological parameters including; age, and sex of the patient, type, site, size and grade of dysplasia of colorectal adenomas.Methods: Forty-seven polypectomy specimens of colorectal adenomas were retrieved from the archival materials of the Gastrointestinal and Hepatic Diseases Teaching Hospital in Baghdad from 2009 - 2010. Four µm section specimens were stained by immunohistochemical technique with Ki-67 and P53 tumor markers. P-values <0.05 were considered statistically significant.Results: Immunohistochemical expressions of Ki-67 and P53 had a significant correlation with the size and grade of dysplasia in colorectal adenomas. However, there was no significant correlation among the immunohistochemical expression of Ki-67 and P53 with the age and gender of the patient, and the type and site of colorectal adenomas. There was no significant correlation between Ki-67 and P53 expressions in colorectal adenomas. Villous adenomas of colorectum showed a significant correlation with the grade of dysplasia, while there was no significant correlation between size and site of colorectal adenoma with the grade of dysplasia.Conclusion: High grade dysplasia with significant positive immunohistochemical markers of Ki-67 and P53 could be valuable parameters for selecting from the total colorectal adenoma population, those most deserving of close surveillance in follow-up cancer prevention programs. It is closely linked with increasing age particularly in patients with a large size adenoma of villous component in their histology.

  14. Distribution of p53 expression in tissue from 774 Danish ovarian tumour patients and its prognostic significance in ovarian carcinomas

    Hogdall, E.V.S.; Christensen, L.; Frederiksen, K.;

    2008-01-01

    The clinical roles played by normal and altered p53 in cancer are under intensive investigation, but larger studies describing the pattern as well as the prognostic value are still needed. The aim of this study was, using tissue array (TA), to examine the overexpression of p53 protein in 774...... epithelial ovarian tumour tissues from Danish women and to evaluate whether p53 tissue expression levels correlate with clinicopathological parameters and prognosis. The distribution of p53 expression levels at different stages of disease, in different histological subtypes, and the prognostic value of p53...... tissue expression were examined. Overall, p53 was expressed in 24/189 (13%) low malignant potential ovarian tumours (LMP) and in 278/585 (48%) ovarian cancers (OC). No significant difference in frequency of p53 tissue expression in LMP tissue was noted with increasing tumour stage (p=0.98). By contrast...

  15. Clofarabine Has Apoptotic Effect on T47D Breast Cancer Cell Line via P53R2 Gene Expression

    Mohammad Rahmati-Yamchi; Nosratollah Zarghami; Hojjatollah Nozad Charoudeh; Yasin Ahmadi; Behzad Baradaran; Mohammad Khalaj-Kondori; Morteza Milani; Abolfazl Akbarzadeh; Maghsud Shaker; Mohammad Pourhassan-Moghaddam

    2015-01-01

    Purpose: Clofarabine, a purine nucleoside analogue and inhibitor of Ribonucleotide Reductase (RR), is used for treatment of leukemia. Clofarabine-induced defect in DNA replication, induces p53 and subsequently P53R2 genes as subunit of RR. clofarabine deregulated P53R2 gene expression leading to the elevated levels of P53R2 which impose resistance to DNA damaging drugs. In this study the apoptotic and cytotoxic effects of clofarabine has been investigated on breast cancer ce...

  16. The Prognostic Impact of p53 Expression on Sporadic Colorectal Cancer Is Dependent on p21 Status

    The prognostic value of p53 and p21 expression in colorectal cancer is still under debate. We hypothesize that the prognostic impact of p53 expression is dependent on p21 status. The expression of p53 and p21 was immunohistochemically investigated in a prospective cohort of 116 patients with UICC stage II and III sporadic colorectal cancer. The results were correlated with overall and recurrence-free survival. The mean observation period was 51.8 ± 2.5 months. Expression of p53 was observed in 72 tumors (63%). Overall survival was significantly better in patients with p53-positive carcinomas than in those without p53 expression (p = 0.048). No differences were found in recurrence-free survival (p = 0.161). The p53+/p21− combination was seen in 68% (n = 49), the p53+/p21+ combination in 32% (n = 23). Patients with p53+/p21− carcinomas had significantly better overall and recurrence-free survival than those with p53+/p21+ (p < 0.0001 resp. p = 0.003). Our data suggest that the prognostic impact of p53 expression on sporadic colorectal cancer is dependent on p21 status

  17. Activation of endogenous p53 by combined p19Arf gene transfer and nutlin-3 drug treatment modalities in the murine cell lines B16 and C6

    Reactivation of p53 by either gene transfer or pharmacologic approaches may compensate for loss of p19Arf or excess mdm2 expression, common events in melanoma and glioma. In our previous work, we constructed the pCLPG retroviral vector where transgene expression is controlled by p53 through a p53-responsive promoter. The use of this vector to introduce p19Arf into tumor cells that harbor p53wt should yield viral expression of p19Arf which, in turn, would activate the endogenous p53 and result in enhanced vector expression and tumor suppression. Since nutlin-3 can activate p53 by blocking its interaction with mdm2, we explored the possibility that the combination of p19Arf gene transfer and nutlin-3 drug treatment may provide an additive benefit in stimulating p53 function. B16 (mouse melanoma) and C6 (rat glioma) cell lines, which harbor p53wt, were transduced with pCLPGp19 and these were additionally treated with nutlin-3 or the DNA damaging agent, doxorubicin. Viral expression was confirmed by Western, Northern and immunofluorescence assays. p53 function was assessed by reporter gene activity provided by a p53-responsive construct. Alterations in proliferation and viability were measured by colony formation, growth curve, cell cycle and MTT assays. In an animal model, B16 cells were treated with the pCLPGp19 virus and/or drugs before subcutaneous injection in C57BL/6 mice, observation of tumor progression and histopathologic analyses. Here we show that the functional activation of endogenous p53wt in B16 was particularly challenging, but accomplished when combined gene transfer and drug treatments were applied, resulting in increased transactivation by p53, marked cell cycle alteration and reduced viability in culture. In an animal model, B16 cells treated with both p19Arf and nutlin-3 yielded increased necrosis and decreased BrdU marking. In comparison, C6 cells were quite susceptible to either treatment, yet p53 was further activated by the combination of p19

  18. Immunohistochemical detection of p53 and MDM2 expressions in liposarcoma with World health organization classification

    A Arici

    2013-01-01

    Full Text Available Background: Liposarcomas are among the most common soft tissue sarcomas in adulthood. Aim: The purpose of the study is to perform a histopathologic typing according to World Health Organization (WHO classification of cases diagnosed with liposarcoma and to examine the difference of p53 and MDM2 expressions. Materials and Methods: The haematoxylin-eosin stained sections of 48 subjects enrolled in the study have been evaluated on the basis of the WHO classification for liposarcoma and sections stained using p53 and MDM2. Statistical Analysis Used: Chi-Square test was applied. Results: 20 subjects were diagnosed with well-differentiated liposarcoma (WLS, 16 myxoid liposarcoma (ML, 7 pleomorphic liposarcoma (PL, and 5 de-differentiated liposarcoma (DLS. The number of cases stained positive with MDM2 and p53 were positive correlated in all subjects (P = 0.02. p53 and MDM2 positivity increased in high grade tumors (P = 0.01. Conclusion: p53 and MDM2 immuno-reactivity was found to be potentially useful in liposarcoma diagnosis but a definitive implication would be rather unhealthy due to the small number of cases in our study.

  19. dNTP Supply Gene Expression Patterns after P53 Loss

    Radivoyevitch, Tomas, E-mail: txr24@case.edu [Departments of Epidemiology and Biostatistics, General Medical Sciences (Oncology), and Pathology, Case Western Reserve School of Medicine, Cleveland, OH 44106 (United States); Saunthararajah, Yogen [Department of Translational Hematology & Oncology Research, Taussig Cancer Institute, Cleveland Clinic, 9500 Euclid Ave. R40, Cleveland, OH 44195 (United States); Pink, John [Departments of Epidemiology and Biostatistics, General Medical Sciences (Oncology), and Pathology, Case Western Reserve School of Medicine, Cleveland, OH 44106 (United States); Ferris, Gina [Department of Radiation Oncology, University Hospitals Case Medical Center and Case Western Reserve School of Medicine, Cleveland, OH 44106 (United States); Lent, Ian; Jackson, Mark; Junk, Damian [Departments of Epidemiology and Biostatistics, General Medical Sciences (Oncology), and Pathology, Case Western Reserve School of Medicine, Cleveland, OH 44106 (United States); Kunos, Charles A. [Department of Radiation Oncology, University Hospitals Case Medical Center and Case Western Reserve School of Medicine, Cleveland, OH 44106 (United States)

    2012-11-20

    Loss of the transcription factor p53 implies mRNA losses of target genes such as the p53R2 subunit of human ribonucleotide reductase (RNR). We hypothesized that other genes in the dNTP supply system would compensate for such p53R2 losses and looked for this in our own data and in data of the Gene Expression Omnibus (GEO). We found that the de novo dNTP supply system compensates for p53R2 losses with increases in RNR subunit R1, R2, or both. We also found compensatory increases in cytosolic deoxycytidine kinase (dCK) and thymidine kinase 1 (TK1) and in mitochondrial deoxyguanosine kinase (dGK), all of the salvage dNTP supply system; in contrast, the remaining mitochondrial salvage enzyme thymidine kinase 2 (TK2) decreased with p53 loss. Thus, TK2 may be more dedicated to meeting mitochondrial dNTP demands than dGK which may be more obligated to assist cytosolic dNTP supply in meeting nuclear DNA dNTP demands.

  20. dNTP Supply Gene Expression Patterns after P53 Loss

    Loss of the transcription factor p53 implies mRNA losses of target genes such as the p53R2 subunit of human ribonucleotide reductase (RNR). We hypothesized that other genes in the dNTP supply system would compensate for such p53R2 losses and looked for this in our own data and in data of the Gene Expression Omnibus (GEO). We found that the de novo dNTP supply system compensates for p53R2 losses with increases in RNR subunit R1, R2, or both. We also found compensatory increases in cytosolic deoxycytidine kinase (dCK) and thymidine kinase 1 (TK1) and in mitochondrial deoxyguanosine kinase (dGK), all of the salvage dNTP supply system; in contrast, the remaining mitochondrial salvage enzyme thymidine kinase 2 (TK2) decreased with p53 loss. Thus, TK2 may be more dedicated to meeting mitochondrial dNTP demands than dGK which may be more obligated to assist cytosolic dNTP supply in meeting nuclear DNA dNTP demands

  1. Expression of the class II tumor suppressor gene RIG1 is directly regulated by p53 tumor suppressor in cancer cell lines.

    Hsu, Tzu-Hui; Chu, Chin-Chen; Jiang, Shun-Yuan; Hung, May-Whey; Ni, Wen-Chieh; Lin, Huai-En; Chang, Tsu-Chung

    2012-05-01

    Recent studies indicated that the RIG1 (RARRES3/TIG3) plays an important role in cell proliferation, differentiation, and apoptosis. However, the regulatory mechanism of RIG1 gene expression has not been clearly elucidated. In this study, we identified a functional p53 response element (p53RE) in the RIG1 gene promoter. Transfection studies revealed that the RIG1 promoter activity was greatly enhanced by wild type but not mutated p53 protein. Sequence specific mutation of the p53RE abolished p53-mediated transactivation. Specific binding of p53 protein to the rig-p53RE was demonstrated using electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay. Further studies confirmed that the expression of RIG1 mRNA and protein is enhanced through increased p53 protein in HepG2 or in H24-H1299 cells. In conclusion, our results indicated that RIG1 gene is a downstream target of p53 in cancer cell lines. PMID:22616991

  2. Inverse relationship between TCTP/RhoA and p53/ /cyclin A/actin expression in ovarian cancer cells Inverse relationship between TCTP/RhoA and p53/ /cyclin A/actin expression in ovarian cancer cells

    Malgorzata Kloc

    2012-10-01

    Full Text Available The translationally controlled tumor protein (TCTP plays a role in cell growth, cell cycle and cancer
    progression. TCTP controls negatively the stability of the p53 tumor suppressor protein and interacts with the
    cellular cytoskeleton. The deregulation of the actin and cytokeratin cytoskeleton is responsible for the increased
    migratory activity of tumor cells and is linked with poor patient outcome. Recent studies indicate that cyclin A,
    a key regulator of cell cycle, controls actin organization and negatively regulates cell motility via regulation of RhoA
    expression. We studied the organization of actin and cytokeratin cytoskeleton and the expression of TCTP, p53,
    cyclin A, RhoA and actin in HIO180 non-transformed ovarian epithelial cells, and OVCAR3 and SKOV3 (expressing
    low level of inducible p53 ovarian epithelial cancer cells with different metastatic potential. Immunostaining
    and ultrastructural analyses illustrated a dramatic difference in the organization of the cytokeratin and actin
    filaments in non-transformed versus cancer cell lines. We also determined that there is an inverse relationship between
    the level of TCTP/RhoA and actin/p53/cyclin A expression in ovarian cancer cell lines. This previously unidentified
    negative relationship between TCTP/RhoA and actin/p53/cyclin A may suggest that this interaction is linked
    with the high aggressiveness of ovarian cancers.The translationally controlled tumor protein (TCTP plays a role in cell growth, cell cycle and cancer
    progression. TCTP controls negatively the stability of the p53 tumor suppressor protein and interacts with the
    cellular cytoskeleton. The deregulation of the actin and cytokeratin cytoskeleton is responsible for the increased
    migratory activity of tumor cells and is linked with poor patient outcome. Recent studies indicate that cyclin A,
    a key regulator of cell cycle, controls actin organization

  3. Expression of P53(v) protein of peripheral blood in patients with tumor and its relation with age

    To study the expression of P53(v) protein of peripheral blood monocytes in cancer patients and its relation with age, P53(v) proteins were determined in 88 cancer patients and 88 normals by flow cytometry. The levels of P53(v) were (7.76 +- 7.13)% in cancer group and (0.66 +- 0.5)% in normal group. Mean value of P53(v) in the cancers was higher than that in the controls (P<0.01). The expression of P53(v) of peripheral blood raised with age. Conclusion: P53(v) proteins can be detected in peripheral blood monocytes. The detection of P53 expression in human peripheral blood monocytes can be used to screen high risk population with tumor

  4. Pumilio 1 suppresses multiple activators of p53 to safeguard spermatogenesis.

    Chen, Dong; Zheng, Wei; Lin, Aiping; Uyhazi, Katherine; Zhao, Hongyu; Lin, Haifan

    2012-03-01

    During spermatogenesis, germ cells initially expand exponentially through mitoses. A majority of these cells are then eliminated through p53-mediated apoptosis to maintain germline homeostasis. However, the activity of p53 must be precisely modulated, especially suppressed in postmitotic spermatogenic cells, to guarantee robustness of spermatogenesis. Currently, how the suppression is achieved is not understood. Here, we show that Pumilio 1, a posttranscriptional regulator, binds to mRNAs representing 1,527 genes, with significant enrichment for mRNAs involved in pathways regulating p53, cell cycle, and MAPK signaling. In particular, eight mRNAs encoding activators of p53 are repressed by Pumilio 1. Deleting Pumilio 1 results in strong activation of p53 and apoptosis mostly in spermatocytes, which disrupts sperm production and fertility. Removing p53 reduces apoptosis and rescues testicular hypotrophy in Pumilio 1 null mice. These results indicate that key components of the p53 pathway are coordinately regulated by Pumilio 1 at the posttranscriptional level, which may exemplify an RNA operon. PMID:22342750

  5. Evaluation of Proliferative Index (Ki 67 and Suppressor Gene (P53 Expression in Colon Polyps

    Mürüvvet Akçay Çelik

    2015-11-01

    Full Text Available Objective: The aim of this study is to evaluate the presence of Ki 67 proliferation zone of active areas and p53 mutation in colorectal polyps and to compare the results between the polyp types. Methods: Our study included 142 colon polyps. Studies based on the presence of dysplastic areas and dysmorphism in the polyp types that were considered to be non–neoplastic showed that a different pathway may have a role in malignant transformation. The cases were reclassified according to WHO 2010 classification. The tissue sections were stained by immunohistochemistry for Ki 67 and p53 Results: In our study Ki 67 staining was seen 74.5% in the lower zone of the crypt with HP. Ki 67 staining was seen in both the lower zone (40.9% and the upper zone (56.1% of the crypt with AP. In almost all cases, low rate of the p53 staining was observed in the ½ lower zone of crypts. The rate of p53 staining in the upper ½ zone of the crypts was 50% in AP cases. The staining ratio was low in HP and SSA/P Conclusion: The evaluation of polyp histopathology and Ki 67, p53, and molecular genetic with serologic characteristics of patients are required in parallel reviews.

  6. DNA PLOIDY, EXPRESSION OF p53 PROTEIN AND METASTATIC BEHAVIOUR OF GASTRIC CARCINOMA

    辛彦; 赵凤凯; 吴东瑛; 王艳萍; 徐蕾; BurnneCurran; MaryLeader; KristinHenry

    1996-01-01

    DNA ploidy of 57 gastric carcinomas with metastases (12 liver,1 adrenal,4 ovary and 48 lymph node)were measured by flow cytometry.DNA anueploidy was significantly related to liver metastases;9 out of 12 gastric carcinomas with liver metastases were anueploid (75%) as compared to 13 out of 45 (28.8%) of cases without liver metastases(P<0.01);the one gastric carcinoma with adrenal merastasis was also anueploid.DNA ploidy was not related to ovarian or lymph node metastases.Anothber interesting finding was that all of 3 gastric carcinomas with liver metastases but no p53 protein expression were anueploid. The expression of p53 protein was not related to ovarian metastases. The results suggested thatan anueplold DNA pattern and the expression of p53 protein are both objective markers valuable in predict-ing high risk potential of metastases to the liver, and that the combined detection of these markers can bea most useful method in the follow-op of patients with gastric carcinoma in detecting those at high risk ofdeveAoping metastases following surgical resection. Also the poorer prognosis of patients with gastric carci-noma showing an anueploid DNA pattern may be related to the development of distant organ metastasesthrough the blood vascular system. Furthermore, the clone of gastric carcinoma cells which accumulate p53protein or show an anueplold DNA pattern may have a ca.sative role in the development of liver (~adrenal) metastases.

  7. Structural basis of how stress-induced MDMX phosphorylation activates p53.

    Chen, X; Gohain, N; Zhan, C; Lu, W-Y; Pazgier, M; Lu, W

    2016-04-14

    The tumor-suppressor protein p53 is tightly controlled in normal cells by its two negative regulators--the E3 ubiquitin ligase MDM2 and its homolog MDMX. Under stressed conditions such as DNA damage, p53 escapes MDM2- and MDMX-mediated functional inhibition and degradation, acting to prevent damaged cells from proliferating through induction of cell cycle arrest, DNA repair, senescence or apoptosis. Ample evidence suggests that stress signals induce phosphorylation of MDM2 and MDMX, leading to p53 activation. However, the structural basis of stress-induced p53 activation remains poorly understood because of the paucity of technical means to produce site-specifically phosphorylated MDM2 and MDMX proteins for biochemical and biophysical studies. Herein, we report total chemical synthesis, via native chemical ligation, and functional characterization of (24-108)MDMX and its Tyr99-phosphorylated analog with respect to their ability to interact with a panel of p53-derived peptide ligands and PMI, a p53-mimicking but more potent peptide antagonist of MDMX, using FP and surface plasmon resonance techniques. Phosphorylation of MDMX at Tyr99 weakens peptide binding by approximately two orders of magnitude. Comparative X-ray crystallographic analyses of MDMX and of pTyr99 MDMX in complex with PMI as well as modeling studies reveal that the phosphate group of pTyr99 imposes extensive steric clashes with the C-terminus of PMI or p53 peptide and induces a significant lateral shift of the peptide ligand, contributing to the dramatic decrease in the binding affinity of MDMX for p53. Because DNA damage activates c-Abl tyrosine kinase that phosphorylates MDMX at Tyr99, our findings afford a rare glimpse at the structural level of how stress-induced MDMX phosphorylation dislodges p53 from the inhibitory complex and activates it in response to DNA damage. PMID:26148237

  8. Study of p53 protein expression levels from irradiated peripheral blood lymphocytes for biodosimetry

    Cavalcanti, M.B.; Fernandes, T.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Amaral, A. [Universite Paris XII (UPXII) (France); Melo, J.A. [Centro de Radioterapia de Pernambuco (CERAPE), PE (Brazil); Neves, M.A.B.; Machado, C.G.F, E-mail: maribrayner@yahoo.com.br [Fundacao de Hematologia e Hemoterapia de Pernambuco, PE (Brazil)

    2005-07-01

    Biodosimetry can be defined as the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. Scoring of unstable chromosomal aberrations and micronuclei, from in vitro irradiated peripheral blood lymphocytes, is commonly used for biodosimetry based on cytogenetic analysis. However, this method of analysis is time-consuming, which may represent a pitfall when fast investigation of a possible exposure to ionizing radiation (IR) is needed. The interaction of IR with the living cell can cause injuries in the DNA molecules. However, normal cells possess mechanisms of repair that are capable to correct those damages. During the repair process of the DNA various proteins are expressed. Among these proteins, p53 plays an important role. This protein is a transcription factor that helps in the maintenance of the genomic integrity. p53 protein is found into the cytoplasm in reduced concentrations and has a short average life. However, expression of p53 protein can be induced by DNA harmful radioinduced, which increases the concentration and the average life of this protein, making possible its detection. Thus, the correlation between the increasing of p53 expression and the irradiation may constitute a fast and reliable method of individual monitoring in cases of accidental or suspected exposures to IR. In this context, the objective of this research was to evaluate the p53 protein expression levels from lymphocytes of the human peripheral blood after in vitro irradiation. For this, samples of peripheral blood from healthy individuals were irradiated with known doses. Lymphocytes were separated on ficoll gradient by centrifugation and re-suspended at 1x 10{sub 6}/mL in RPMI medium enriched with fetal calf serum. Hence, lymphocytes were incubated in 5% CO{sub 2} at 37 deg C prior to the methodology of flow cytometry, using intranuclear antigens for the quantification of p53. In this report, the methodology performed and the results

  9. Prognostic role of p53 protein expression in epidermoid carcinoma of the anal canal

    Purpose: To assess the prognostic significance of p53 protein expression in patients with primary epidermoid carcinoma of the anal canal managed by radiation therapy (XRT), 5-fluorouracil (5-FU), and mitomycin C (MMC). Methods and Materials: From January 1991 to December 1993, 58 consecutive patients with primary epidermoid carcinoma of the anal canal were treated in a prospectively designed protocol of XRT (24 Gy/12--3((1)/(2)) wk split--28 Gy/14) and concurrent 5-FU (1000 mg/m2/day 1-4) and MMC (10 mg/m2 day 1) of each cycle of XRT. Paraffin-embedded tumor samples were unavailable in 9 patients, leaving 49 patients in the study. Expression of p53 protein was studied using immunohistochemistry and quantified as percent tumor nuclei showing positive staining. Actuarial survival and disease-free survival (DFS) rates were estimated by the Kaplan-Meier method, and compared using the log-rank test. A Cox proportional hazard model was used for the multivariable analysis. Results: There were 6 T1, 26 T2, 7 T3, and 10 T4 lesions. Primary tumor sizes ranged from 1-15 cm with a median of 4 cm. There were 6 patients with nodal metastases. Median follow-up was 4.5 years. Positive nuclear immunostaining for p53 was observed in 40 of 49 patients. The median percent positive staining was 5%, with 13, 9, and 18 patients showing staining in <5%, 5 to <10%, and 10-50% of tumor nuclei respectively. There was no correlation of percent p53 staining with gender, age, tumor stage, size, or histology. Local, regional, and distant failures were observed in 12, 2, and 2 patients respectively. The 5-yr survival and DFS were 84% and 64% respectively. In univariate analysis, the only prognostic variable for survival was gender. For DFS, advanced T category and large tumor size were predictive of poor DFS. In multivariate analysis, poor DFS was associated with high T category (p = 0.0008), basaloid histology (p = 0.001), male gender (p = 0.002), and increasing percent of p53 protein expression

  10. Topical formulation engendered alteration in p53 and cyclobutane pyrimidine dimer expression in chronic photodamaged patients.

    Spencer, James M; Morgan, Michael B; Trapp, Kara M; Moon, Summer D

    2013-03-01

    While the clinical attributes of photoaging are well characterized in the literature, the pathogenic mechanisms that underlie these changes are incompletely elucidated. At the molecular level, p53 tumor-suppressor gene product mediated excision repair of ultraviolet (UV)-induced DNA damage is a critical effector in xeroderma pigmentosum (XP) and potentially in conventional photoaging. We examined p53 activity and measured UV-induced DNA damage via cyclobutane pyrimidine dimers (CPDs) quantitatively in 20 volunteers before and after an 8-week, open-label prospective topical application of a proprietary DNA recovery serum (Celfix). There was a statistically significant decrease in immunohistochemically determined p53 and CPD levels. While these data are preliminary, the findings lend support to the theoretical possibility of a topical agent reversing the effects of photodamage at the molecular level and, potentially, an ameliorative outcome clinically. PMID:23545918

  11. Frequency of Ki-67 (MIB-1 and P53 expressions among patients with prostate cancer

    Seyed Hamid Madani

    2011-01-01

    Full Text Available Context: Prostate cancer is the most common malignant tumor in men. Tumor grade is one of the most important prognostic factors of prostate cancer. P53 and Ki-67 expressions have also been considered to be prognostic factors. Aims: This study was performed to investigate the frequency of these proteins expression and compare the obtained results with Gleason′s grading. Settings and Design: In this cross-sectional study, 49 paraffin blocks of prostate cancers were assessed. Tumor grade was determined according to the Gleason′s criteria. Materials and Methods: Ki-67 and P53 expressions were determined by immunohistochemical staining. Statistical Analysis: The obtained results were analyzed and evaluated using Spearman′s statistical test (SPSS version 15. Results: Three out of 49 (6.1% cases were well differentiated, 21 (43% moderately differentiated and 25 (51% were poorly differentiated. P53 was negative in all well-differentiated cases. Ki-67 was negative in 14 cases (28% including all well-differentiated tumors. Among moderately and poorly differentiated tumors Ki-67 was negative in eight (38% and three (12% of cases, respectively. A statistically significant relation was observed between the increased Ki-67 labeling index (LI and increased Gleason′s grade. Conversely, no statistically significant relation was found between P53 expression and increased Gleason′s grade. Conclusions: According to the findings of this study, it seems that Ki-67 can be used as a prognostic factor for prostate cancer. On the other hand, the probable relation between P-53 and prostate cancer prognosis requires further studies.

  12. Stapled peptides with improved potency and specificity that activate p53.

    Brown, Christopher J; Quah, Soo T; Jong, Janice; Goh, Amanda M; Chiam, Poh C; Khoo, Kian H; Choong, Meng L; Lee, May A; Yurlova, Larisa; Zolghadr, Kourosh; Joseph, Thomas L; Verma, Chandra S; Lane, David P

    2013-03-15

    By using a phage display derived peptide as an initial template, compounds have been developed that are highly specific against Mdm2/Mdm4. These compounds exhibit greater potency in p53 activation and protein-protein interaction assays than a compound derived from the p53 wild-type sequence. Unlike Nutlin, a small molecule inhibitor of Mdm2/Mdm4, the phage derived compounds can arrest cells resistant to p53 induced apoptosis over a wide concentration range without cellular toxicity, suggesting they are highly suitable for cyclotherapy. PMID:23214419

  13. Effects of Δ40p53, an isoform of p53 lacking the N-terminus, on transactivation capacity of the tumor suppressor protein p53

    The p53 protein is expressed as multiple isoforms that differ in their N- and C-terminus due to alternative splicing, promoter or codon initiation usage. Δ40p53 lacks the first 39 residues containing the main transcriptional activation domain, resulting from initiation of translation at AUG +40 in fully spliced p53 mRNA or in a specific variant mRNA retaining intron 2. Overexpression of Δ40p53 antagonizes wild-type p53 in vitro. However, animal models of Δ40p53 in mouse or Zebrafish have shown complex phenotypes suggestive of p53-dependent growth suppressive effects. We have co-transfected expression vectors for p53 and Δ40p53 in p53-null cell lines Saos-2 and H1299 to show that Δ40p53 forms mixed oligomers with p53 that bind to DNA and modulate the transcription of a generic p53-dependent reporter gene. In H1299 cells, co-expression of the two proteins induced a decrease in transcription with amplitude that depended upon the predicted composition of the hetero-tetramer. In Saos-2, a paradoxical effect was observed, with a small increase in activity for hetero-tetramers predicted to contain 1 or 2 monomers of Δ40p53 and a decrease at higher Δ40p53/p53 ratios. In this cell line, co-transfection of Δ40p53 prevented Hdm2-mediated degradation of p53. Δ40p53 modulates transcriptional activity by interfering with the binding of Hdm2 to hetero-tetramers containing both Δ40p53 and p53. These results provide a basis for growth suppressive effects in animal models co-expressing roughly similar levels of p53 and Δ40p53

  14. Contribution to the investigation of the p53 in vivo and in vitro trans-activation activity

    Among the body's defence mechanisms, the programmed cellular death or apoptosis is an important safeguard way which allows the body to get rid of the injured cells before they acquire steady genetic modifications leading to an anarchistic multiplication. As p53 tumor suppressor gene plays a predominant role within this process, this research report first presents the p53 protein, its structure, its activities as a transcription factor, its modifications and the implications on its functional activities, its biological activities, and describes the p53 intracellular rate regulation and the use of this protein in radiology, particularly in 'in vivo' investigations on irradiated mice. It also presents the p53 family. Then, the author reports experimental investigations on possible other genes which could be trans-activated by p53. A gene is identified as a new target gene. She also demonstrates a new p53 activation path induced by another member of the p53 family, the p73 alpha protein

  15. On Diagnostic Value of Serum P53 Antibody Level and P53 Expression in Patients with Lung Cancer%肺癌患者血清P53抗体及肺癌组织P53表达对肺癌诊断价值的研究

    吴翠翠; 修冬莹; 张雪琦

    2014-01-01

    目的:探讨肺癌患者血清P53抗体水平及肺癌组织P53表达对肺癌诊断的价值.方法采用ELISA法检测肺癌患者血清P53抗体水平,并采用免疫组化法检测肺癌组织P53表达情况.结果肺癌患者血清P53抗体(17.84±8.73)ng/L水平比正常对照组(5.43±1.90)ng/L显著升高(P<0.001),肺癌患者血清P53抗体水平与肿瘤大小、淋巴转移、远端转移、TNM分期有关.肺癌患者癌组织P53表达的阳性率为61.5%(168/273),肺癌患者癌组织P53阳性表达率与肿瘤大小、淋巴转移、远端转移、TNM分期、分化程度、病理类型有关.结论血清P53抗体水平与癌组织中的表达有着良好的平行关系,测定血清P53抗体水平或检查肺癌患者癌组织P53的表达可对肺癌的诊断、分期、治疗和预后提供重要依据.%Objective To investigate the diagnostic value of P53 antibody level and P53 expression in patients with lung cancer. Methods The level of serum P53 antibody and the expression of P53 in lung cancer tissue were detected by enzyme-linked immunosorbent assay ( ELISA) and immunology chemistry,respectively. Results The level of P53 antibody (17. 84±8. 73)ng/L was significantly higher in serum from lung cancer patients than that in serum from normal control group(5. 43±1. 90)ng/L(P<0. 001),and was related to the tumor size,lymph node metastasis,distal metastasis and TNM staging. The positive rate of P53 expression was 61. 5%(168/273) in lung cancer tissue, and was related to the size of tumor, lymph node metastasis, distal metastasis, TNM stages, differentiation and pathologic type. Conclusion The level of serum P53 antibody was paralleled to its expression in cancer tissues. The detection of serum P53 antibody level or the tissue expression of P53 in lung cancer tissue can provide an important evidence for the diagnosis,staging,treatment and prognosis of lung cancer.

  16. p53 expression in human rectal tissue after radiotherapy: upregulation in normal mucosa versus functional loss in rectal carcinomas

    Purpose: In vitro, ionizing radiation of epithelial cells leads to upregulation of wild-type p53 and subsequent induction of p21waf1. The effect of radiotherapy (RT) on the expression of these proteins in patients is unknown. We assessed the influence of RT on the expression of p53 and p21waf1 in normal mucosa and rectal carcinomas in vivo. Methods: Tumor and normal tissue samples were derived from rectal cancer patients randomized in a clinical trial in which the value of preoperative RT was evaluated. p53 and p21waf1 expression was determined in 51 irradiated and 52 nonirradiated patients using immunohistochemistry. Results: In normal mucosa, both p53 and p21waf1 were strongly upregulated after RT compared with the expression in unirradiated normal tissue (p waf1 was found in the irradiated vs. nonirradiated group. In the few rectal tumors with wild-type p53, induction of p53 after RT did not necessarily lead to upregulation of p21waf1. Conclusion: These findings demonstrate that in normal mucosa, a functional p53-p21waf1 pathway is present, whereas in tumor cells it is defective in almost all cases because of either p53 mutation or down- or upstream disruption in tumors with wild-type p53. Therefore, we believe that the role of p53 expression as a single prognostic marker in rectal cancer needs reconsideration

  17. 14-3-3 Sigma And p53 Expression in Gastric Cancer and Its Clinical Applications

    Gilbert Mühlmann

    2010-01-01

    Full Text Available 14-3-3 sigma (σ induces G2 arrest enabling the repair of damaged DNA. The function of 14-3-3 σ is frequently lost in tumor cells, indicating a potential tumor suppressor function. The purpose of this study was to evaluate the prognostic value of 14-3-3 σ expression in human gastric cancer. 14-3-3 σ expression was analyzed by immunohistochemistry in 157 tumor samples of patients, who underwent resection for gastric cancer. Since 14-3-3 σ is involved in the p53 network, p53 expression was detected in parallel and correlated with 14-3-3 σ. 14-3-3 σ was found to be overexpressed in 75 (47.8% of 157 cases, the overexpression rate of p53 protein was 27.4%. 14-3-3 σ overexpression was statistically significantly associated with pT-stage (p=0.041 pN-stage (p=0.015 and UICC-stage (p=0.019 and showed a borderline significance with Lauren classification (p=0.057. Univariate survival calculations revealed a coexistent 14-3-3 σ and p53 overexpression as a significant predictor of disease-free survival. Multivariate analysis did not unfold 14-3-3 as an independent prognostic factor for disease-free survival and overall survival. Concomitant 14-3-3 σ and p53 overexpression in tumor cells of patients with gastric cancer identifies a population of patients with relatively unfavorable prognosis.

  18. Proteasome inhibition mediates p53 reactivation and anti-cancer activity of 6-Gingerol in cervical cancer cells

    Rastogi, Namrata; Duggal, Shivali; Singh, Shailendra Kumar; Porwal, Konica; Srivastava, Vikas Kumar; Maurya, Rakesh; Bhatt, Madan L.B.; Mishra, Durga Prasad

    2015-01-01

    Human papilloma virus (HPV) expressing E6 and E7 oncoproteins, is known to inactivate the tumor suppressor p53 through proteasomal degradation in cervical cancers. Therefore, use of small molecules for inhibition of proteasome function and induction of p53 reactivation is a promising strategy for induction of apoptosis in cervical cancer cells. The polyphenolic alkanone, 6-Gingerol (6G), present in the pungent extracts of ginger (Zingiber officinale Roscoe) has shown potent anti-tumorigenic and pro-apoptotic activities against a variety of cancers. In this study we explored the molecular mechanism of action of 6G in human cervical cancer cells in vitro and in vivo. 6G potently inhibited proliferation of the HPV positive cervical cancer cells. 6G was found to: (i) inhibit the chymotrypsin activity of proteasomes, (ii) induce reactivation of p53, (iii) increase levels of p21, (iv) induce DNA damage and G2/M cell cycle arrest, (v) alter expression levels of p53-associated apoptotic markers like, cleaved caspase-3 and PARP, and (vi) potentiate the cytotoxicity of cisplatin. 6G treatment induced significant reduction of tumor volume, tumor weight, proteasome inhibition and p53 accumulation in HeLa xenograft tumor cells in vivo. The 6G treatment was devoid of toxic effects as it did not affect body weights, hematological and osteogenic parameters. Taken together, our data underscores the therapeutic and chemosensitizing effects of 6G in the management and treatment of cervical cancer. PMID:26621832

  19. HCV NS5A abrogates p53 protein function by interfering with p53-DNA binding

    Guo-Zhong Gong; Yong-Fang Jiang; Yan He; Li-Ying Lai; Ying-Hua Zhu; Xian-Shi Su

    2004-01-01

    AIM: To evaluate the inhibition effect of HCV NS5A on p53 transactivation on p21 promoter and explore its possible mechanism for influencing p53 function.METHODS: p53 function of transactivation on p21 promoter was studied with a luciferase reporter system in which the luciferase gene is driven by p21 promoter, and the p53-DNA binding ability was observed with the use of electrophoretic mobility-shift assay (EMSA). Lipofectin mediated p53 or HCV NS5A expression vectors were used to transfect hepatoma cell lines to observe whether HCV NS5A could abrogate the binding ability of p53 to its specific DNA sequence and p53 transactivation on p21 promoter.Western blot experiment was used for detection of HCV NS5A and p53 proteins expression.RESULTS: Relative luciferase activity driven by p21 promoter increased significantly in the presence of endogenous p53 protein. Compared to the control group, exogenous p53 protein also stimulated p21 promoter driven luciferase gene expression in a dose-dependent way. HCV NS5A protein gradually inhibited both endogenous and exogenous p53 transactivation on p21 promoter with increase of the dose of HCV NS5A expression plasmid. By the experiment of EMSA, we could find p53 binding to its specific DNA sequence and, when co-transfected with increased dose of HCV NS5A expression vector, the p53 binding affinity to its DNA gradually decreased and finally disappeared. Between the Huh 7 cells transfected with p53 expression vector alone or co-transfected with HCV NS5A expression vector, there was no difference in the p53 protein expression.CONCLUSION: HCV NS5A inhibits p53 transactivation on p21 promoter through abrogating p53 binding affinity to its specific DNA sequence. It does not affect p53 protein expression.

  20. Apoptosis, proliferation and p53 gene expression of H. pylori associated gastric epithelial lesions

    Zhong Zhang1; Yuan Yuan; Hua Gao; Ming Dong; Lan Wang; Yue-Hua Gong

    2001-01-01

    AIM: To study the relationship between Helicobacter pylori (H. Pylori) and gastric carcinoma and its possible pathogenesis by H. Pylori. METHODS: DNEL technique and immunohistochemical technique were used to study the state of apoptosis,proliferation and p53 gene expression. A total of 100 gastric mucosal biopsy specimens, including 20 normal mucosa, 30H. Pylori-negative and 30 H. Pylorf-positive gastric precancerous lesions along with 20 gastric carcinomas were studied. RESULTS: There were several apoptotic cells in the superficial epithelium and a few proliferative cells within the neck of gastric glands, and no p53 protein expression in normal mucosa. In gastric carcinoma, there were few apoptotic cells, while there were a large number of proliferative cells, and expression of p53 protein significantly was increased. In the phase of metaplasia, the apoptotic index (Al, 4.36% ± 1.95%), proliferative index (PI, 19.11% ± 6.79%) and positivity of p53 expression (46.7%) in H. Pylori-positive group were higher than those in normal mucosa (P< 0.01). Al in H. Pylori-positive group was higher than that in H. Pylori-negative group (3.81% ±1.76%), PI in H. Pylori-positive group was higher than that in H. Pylori-negative group (12.25% ±5.63%, P<0.01 ). In the phase of dysplasia, Al (2.31% ± 1.10%) in H. Pylori-positive group was lower (3.05% ± 1.29%) than that in H. Pylori-negative group, but PI (33.89% ± 11.65%)wassignificantly higher(22.09± 8018%, P< 0.01). In phases of metaplasia, dysplasia and gastric cancer in the H. Pylori-positive group, Als had an evidently graduall decreasing trend (P < 0.01 ), while Pis had an evidently gradual increasing trend (P< 0.05 or P< 0.01), and there was also a trend of gradual increase in the expression of p53 gene. CONCLUSION: In the course of the formation of gastric carcinoma, proliferation of gastric mucosa can be greatly increased by H. Pylori, and H. Pylori can induce apoptosis in the phase of metaplasia but in the phase of

  1. Toxicity of depleted uranium complexes is independent of p53 activity

    Heintze, Ellie; Aguilera, Camille; Davis, Malia; Fricker, Avery; Li, Qiang; Martinez, Jesse; Matthew J. Gage

    2010-01-01

    The p53 tumor suppressor protein is one of the key checkpoints in cellular response to a variety of stress mechanisms, including exposure to various toxic metal complexes. Previous studies have demonstrated that arsenic and chromium complexes are able to activate p53, but there is a dearth of data investigating whether uranium complexes exhibit similar effects. The use of depleted uranium (DU) has increased in recent years, raising concern about DU’s potential carcinogenic effects. Previous s...

  2. Pumilio 1 Suppresses Multiple Activators of p53 to Safeguard Spermatogenesis

    Chen, Dong; Zheng, Wei; Lin, Aiping; Uyhazi, Katherine; Zhao, Hongyu; Lin, Haifan

    2012-01-01

    During spermatogenesis, germ cells initially expand exponentially through mitoses. A majority of these cells are then eliminated through p53-mediated apoptosis to maintain germline homeostasis [1–4]. However, the activity of p53 must be precisely modulated, especially suppressed in postmitotic spermatogenic cells, to guarantee robustness of spermatogenesis. Currently, how the suppression is achieved is not understood. Here, we show that Pumilio 1, a posttranscriptional regulator, binds to mRN...

  3. RNF2/Ring1b negatively regulates p53 expression in selective cancer cell types to promote tumor development

    Su, Wen-Jing; Fang, Jun-shun; Cheng, Feng; Liu, Chao; Zhou, Fang; Zhang, Jian

    2013-01-01

    Large numbers of studies have focused on the posttranslational regulation of p53 activity. One of the best-known negative regulators for p53 is MDM2, an E3 ubiquitin ligase that promotes p53 degradation through proteasome degradation pathways. Additional E3 ligases have also been reported to negatively regulate p53. However, whether these E3 ligases have distinct/overlapping roles in the regulation of p53 is largely unknown. In this study, we identify RNF2 (ring finger protein 2) as an E3 lig...

  4. Expression screening using a Medaka cDNA library identifies evolutionarily conserved regulators of the p53/Mdm2 pathway

    P. Zhang; Kratz, A.S.; M. Salama; Elabd, S.; Heinrich, T; Wittbrodt, J.; Blattner, C.; G Davidson

    2015-01-01

    Background The p53 tumor suppressor protein is mainly regulated by alterations in the half-life of the protein, resulting in significant differences in p53 protein levels in cells. The major regulator of this process is Mdm2, which ubiquitinates p53 and targets it for proteasomal degradation. This process can be enhanced or reduced by proteins that associate with p53 or Mdm2 and several proteins have been identified with such an activity. Furthermore, additional ubiquitin ligases for p53 have...

  5. Isoformes du domaine N-terminal du suppresseur de tumeur p53 : sur l'activité transcriptionnelle de p53 et expression dans les mélanomes cutanés

    Hafsi, Hind

    2012-01-01

    The p53 tumour suppressor protein has a highly complex pattern of regulation at transcriptional and posttranslationallevels. The discovery of p53 isoforms has added another layer of complexity to the mechanisms thatregulate p53 functions. Indeed, p53 is expressed as 12 isoforms that differ in their N- and C-terminus due toalternative splicing, promoter or codon initiation usage. So far, there is limited understanding of the patterns ofexpression and of the functions of each of these isoforms....

  6. Prognostic Significance and Gene Expression Profiles of p53 Mutations in Microsatellite-Stable Stage III Colorectal Adenocarcinomas

    Katkoori, Venkat R.; Shanmugam, Chandrakumar; Jia, Xu; Vitta, Swaroop P.; Sthanam, Meenakshi; Callens, Tom; Messiaen, Ludwine; Chen, Dongquan; Zhang, Bin; Bumpers, Harvey L.; Samuel, Temesgen; Manne, Upender

    2012-01-01

    Although the prognostic value of p53 abnormalities in Stage III microsatellite stable (MSS) colorectal cancers (CRCs) is known, the gene expression profiles specific to the p53 status in the MSS background are not known. Therefore, the current investigation has focused on identification and validation of the gene expression profiles associated with p53 mutant phenotypes in MSS Stage III CRCs. Genomic DNA extracted from 135 formalin-fixed paraffin-embedded tissues, was analyzed for microsatell...

  7. The expression of p16, p53 induced by metallic biliary stent in canine

    Objective: To explore the value of the metallic biliary stents in inducing the expression of anti-oncogenes. Methods: The biliary stents were implanted in the inferior segments of CBD after a percutaneous transhepatic puncture at cholecyst in 24 dogs. After a generally observing time of half a year, the median abdominal incisions were made on the dogs under general anesthesia and the bile duct wall covered by the stents (group I) and uncovered (group II) were cut respectively. The expression of p16, p53, p15, Bcl-2 and K-ras in bile duct wall were detected by RT-PCR, and the positive rates of these gene expression were calculated. The differences between the two groups were analyzed by chi-square test for the statistics. Results: The animal models were successfully set in 20 of 24 dogs. The positive rates of p16, p53 gene expression were 80% (16/20), 45% (9/20) in the bile duct wall covered by the stents and 15% (3/20), 0% in the bile duct wall uncovered respectively, there were significant differences between the two groups (χ2=16.94, 9.17, P0.05). Conclusion: The enhancement of p16, p53 gene expression have some correlations with the implantation of metallic biliary stents. The biliary stenting is strongly recommended for the patients with malignant obstructive jaundice when no contraindications exist. (authors)

  8. Chitosan Nanoparticles-Mediated Wild-Type p53 Gene Delivery for Cancer Gene Therapy: Improvement in Pharmaceutical & Biological Properties (Enhance in Loading, Release, Expression and Stability of P53 Plasmid and Induction of Apoptosis in Carcinoma Cell Line

    Mehrdad Hamidi

    2008-05-01

    Full Text Available Efficient non-viral vectors for gene delivery based on chitosan polymer is dependent on a variety of factors, e.g. loading and lelease capacity, stability in biological system and complex size. This system may have low loading, release and stability capacity. Biodegradable and biocompatible nanoparticles formulated using a chitosan polymer has the potential for sustained and controlled gene delivery. Our hypothesis is that nanoparticles-mediated wild-type p53 gene delivery would result in sustained gene expression, and hence better efficacy with a therapeutic gene. In this study, we have determined the pharmaceutical and biological characterization of Chitosan nanoparticles containing wild-type p53. Nanoparticles containing plasmid were formulated using a microemulsion reverse micellar and ionic gelation techniques. In conclusion, chitosan nanoparticles- p53 complex gene delivery results in sustained and better antiproliferative activity, which could be therapeutically beneficial in cancer treatment.

  9. EXPRESSIONS OF P53, PROLIFERATING CELL NUCLEAR ANITIGEN, BCL-2 PROTEIN AND THEIR SIGNIFICANCE IN SALIVARY ADENOID CYSTIC CARCINOMA

    2000-01-01

    Objective To study the effects of P53, PCNA, Bcl-2 protein and their relationship in salivary adenoid cystic carcinoma(SACC). Methods These proteins were examined by immunohistochemistry. Results Overexpressions of P53 and PCNA were revealed in ACC samples, they were higher than those in (polymorphous adenomas) PA, but expression of Bcl-2 protein was not different between ACC and PA. In 3 subtypes of ACC, expressions of 3 proteins were different. Conclusion Mutations of P53, Bcl-2 may be involed in the occurrence of SACC, expression of PCNA and mutation of P53 may coexist in the development of the SACC.

  10. Survivin inhibits anti-growth effect of p53 activated by aurora B

    Genomic instability and apoptosis evasion are hallmarks of cancer, but the molecular mechanisms governing these processes remain elusive. Here, we found that survivin, a member of the apoptosis-inhibiting gene family, and aurora B kinase, a chromosomal passenger protein, were co-overexpressed in the various glioblastoma cell lines and tumors. Notably, exogenous introduction of the aurora B in human BJ cells was shown to decrease cell growth and increase the senescence-associated β-galactosidase activity by activation of p53 tumor suppressor. However, aurora B overexpression failed to inhibit cell proliferation in BJ and U87MG cells transduced with dominant-negative p53 as well as in p53-/- mouse astrocytes. Aurora B was shown to increase centrosome amplification in the p53-/- astrocytes. Survivin was shown to induce anchorage-independent growth and inhibit anti-proliferation and drug-sensitive apoptosis caused by aurora B. Overexpression of both survivin and aurora B further accelerated the proliferation of BJ cells. Taken together, the present study indicates that survivin should accelerate tumorigenesis by inhibiting the anti-proliferative effect of p53 tumor suppressor that is activated by aurora B in normal and glioblastoma cells containing intact p53

  11. Perturbation of Ribosome Biogenesis Drives Cells into Senescence through 5S RNP-Mediated p53 Activation

    Kazuho Nishimura

    2015-03-01

    Full Text Available The 5S ribonucleoprotein particle (RNP complex, consisting of RPL11, RPL5, and 5S rRNA, is implicated in p53 regulation under ribotoxic stress. Here, we show that the 5S RNP contributes to p53 activation and promotes cellular senescence in response to oncogenic or replicative stress. Oncogenic stress accelerates rRNA transcription and replicative stress delays rRNA processing, resulting in RPL11 and RPL5 accumulation in the ribosome-free fraction, where they bind MDM2. Experimental upregulation of rRNA transcription or downregulation of rRNA processing, mimicking the nucleolus under oncogenic or replicative stress, respectively, also induces RPL11-mediated p53 activation and cellular senescence. We demonstrate that exogenous expression of certain rRNA-processing factors rescues the processing defect, attenuates p53 accumulation, and increases replicative lifespan. To summarize, the nucleolar-5S RNP-p53 pathway functions as a senescence inducer in response to oncogenic and replicative stresses.

  12. Down-expression of tumor protein p53-induced nuclear protein 1 in human gastric cancer

    Pei-Hong Jiang; Yoshiharu Motoo; Stéphane Garcia; Juan Lucio Iovanna; Marie-Josèphe Pébusque; Norio Sawabu

    2006-01-01

    AIM: Overexpression of tumor protein p53-induced nuclear protein 1 (TP53INP1) induces G1 cell cycle arrest and increases p53-mediated apoptosis. To clarify the clinical importance of TP53INP1, we analyzed TP53INP1and p53 expression in gastric cancer.METHODS: TP53INP1 and p53 expression were examined using immunohistochemistry in 142 cases of gastric cancer. The apoptosis of gastric cancer cells was analyzed using the TUNEL method. The relationship between the expression of TP53INP1 and clinicopathological factors was statistically analyzed.RESULTS: TP53INP1 was expressed in 98% (139/142cases) of non-cancerous gastric tissues and was downexpressed in 64% (91/142 cases) of gastric cancer lesions from the same patients. TP53INP1 expression was significantly decreased (43.9%) in poorly differentiated adenocarcinoma compared with well or moderately differentiated adenocarcinoma (81.6%).Cancers invading the submucosa or deeper showed lower positively (59.1%) compared with mucosal cancers (85.2%). Decrease or loss of TP53INP1 expression was significantly correlated with lymphatic invasion (54.3%vs 82.0% without lymphatic invasion) and node-positive patients (31.3% vs 68.3% in node-negative patients).P53 was expressed in 68 (47.9%) patients of gastric cancer, whereas it was absent in normal gastric tissues.A significant association was also observed between TP53INP1 status and the level of apoptosis in tumor cells: the apoptotic index in TP53INP1-positive tissues was significantly higher than that in TP53INP1-negative portions. Finally, when survival data were analyzed,loss of TP53INP1 expression had a significant effect in predicting a poor prognosis (P= 0.0006).CONCLUSION: TP53INP1-positive rate decreases with the progression of gastric cancer. TP53INP1 protein negativity is significantly associated with aggressive pathological phenotypes of gastric cancer. TP53INP1is related to the apoptosis of gastric cancer cells. The decreased expression of the TP53INP1 protein may

  13. Expression de P53 dans les tumeurs à cellules géantes osseuses

    Trottet, Cécile

    2001-01-01

    Le gène de la p53 est considéré comme un gène suppresseur de tumeur. Nous avons étudié son expression dans les tumeurs à cellules géantes osseuses (TCG) pour rechercher s'il pouvait être considéré comme un marqueur prédictif de l'évolution dans les TCG. La protéine p53 a été étudiée dans 33 cas de tumeurs à cellules géantes osseuses par immunohistochimie pour analyser son expression et par Single Strand Conformation Polymorphism (SSCP) pour rechercher la présence de mutations dans les tumeurs...

  14. Expression de P53 dans les tumeurs à cellules géantes osseuses

    Trottet, Cécile; Borisch, Bettina; Bonjour, Jean-Philippe

    2005-01-01

    Le gène de la p53 est considéré comme un gène suppresseur de tumeur. Nous avons étudié son expression dans les tumeurs à cellules géantes osseuses (TCG) pour rechercher s'il pouvait être considéré comme un marqueur prédictif de l'évolution dans les TCG. La protéine p53 a été étudiée dans 33 cas de tumeurs à cellules géantes osseuses par immunohistochimie pour analyser son expression et par Single Strand Conformation Polymorphism (SSCP) pour rechercher la présence de mutations dans les tumeurs...

  15. p53 activation by Ni(II) is a HIF-1α independent response causing caspases 9/3-mediated apoptosis in human lung cells

    Wong, Victor C.; Morse, Jessica L.; Zhitkovich, Anatoly, E-mail: anatoly_zhitkovich@brown.edu

    2013-06-15

    Hypoxia mimic nickel(II) is a human respiratory carcinogen with a suspected epigenetic mode of action. We examined whether Ni(II) elicits a toxicologically significant activation of the tumor suppressor p53, which is typically associated with genotoxic responses. We found that treatments of H460 human lung epithelial cells with NiCl{sub 2} caused activating phosphorylation at p53-Ser15, accumulation of p53 protein and depletion of its inhibitor MDM4 (HDMX). Confirming the activation of p53, its knockdown suppressed the ability of Ni(II) to upregulate MDM2 and p21 (CDKN1A). Unlike DNA damage, induction of GADD45A by Ni(II) was p53-independent. Ni(II) also increased p53-Ser15 phosphorylation and p21 expression in normal human lung fibroblasts. Although Ni(II)-induced stabilization of HIF-1α occurred earlier, it had no effect on p53 accumulation and Ser15 phosphorylation. Ni(II)-treated H460 cells showed no evidence of necrosis and their apoptosis and clonogenic death were suppressed by p53 knockdown. The apoptotic role of p53 involved a transcription-dependent program triggering the initiator caspase 9 and its downstream executioner caspase 3. Two most prominently upregulated proapoptotic genes by Ni(II) were PUMA and NOXA but only PUMA induction required p53. Knockdown of p53 also led to derepression of antiapoptotic MCL1 in Ni(II)-treated cells. Overall, our results indicate that p53 plays a major role in apoptotic death of human lung cells by Ni(II). Chronic exposure to Ni(II) may promote selection of resistant cells with inactivated p53, providing an explanation for the origin of p53 mutations by this epigenetic carcinogen. - Highlights: • Ni(II) is a strong activator of the transcription factor p53. • Apoptosis is a principal form of death by Ni(II) in human lung epithelial cells. • Ni(II)-activated p53 triggers caspases 9/3-mediated apoptotic program. • NOXA and PUMA are two main proapoptotic genes induced by Ni(II). • HIF-1α and p53 are independent

  16. p53 activation by Ni(II) is a HIF-1α independent response causing caspases 9/3-mediated apoptosis in human lung cells

    Hypoxia mimic nickel(II) is a human respiratory carcinogen with a suspected epigenetic mode of action. We examined whether Ni(II) elicits a toxicologically significant activation of the tumor suppressor p53, which is typically associated with genotoxic responses. We found that treatments of H460 human lung epithelial cells with NiCl2 caused activating phosphorylation at p53-Ser15, accumulation of p53 protein and depletion of its inhibitor MDM4 (HDMX). Confirming the activation of p53, its knockdown suppressed the ability of Ni(II) to upregulate MDM2 and p21 (CDKN1A). Unlike DNA damage, induction of GADD45A by Ni(II) was p53-independent. Ni(II) also increased p53-Ser15 phosphorylation and p21 expression in normal human lung fibroblasts. Although Ni(II)-induced stabilization of HIF-1α occurred earlier, it had no effect on p53 accumulation and Ser15 phosphorylation. Ni(II)-treated H460 cells showed no evidence of necrosis and their apoptosis and clonogenic death were suppressed by p53 knockdown. The apoptotic role of p53 involved a transcription-dependent program triggering the initiator caspase 9 and its downstream executioner caspase 3. Two most prominently upregulated proapoptotic genes by Ni(II) were PUMA and NOXA but only PUMA induction required p53. Knockdown of p53 also led to derepression of antiapoptotic MCL1 in Ni(II)-treated cells. Overall, our results indicate that p53 plays a major role in apoptotic death of human lung cells by Ni(II). Chronic exposure to Ni(II) may promote selection of resistant cells with inactivated p53, providing an explanation for the origin of p53 mutations by this epigenetic carcinogen. - Highlights: • Ni(II) is a strong activator of the transcription factor p53. • Apoptosis is a principal form of death by Ni(II) in human lung epithelial cells. • Ni(II)-activated p53 triggers caspases 9/3-mediated apoptotic program. • NOXA and PUMA are two main proapoptotic genes induced by Ni(II). • HIF-1α and p53 are independent

  17. Immunohistochemical Assessment of O6-Methylguanine-DNA Methyltransferase (MGMT) and Its Relationship with p53 Expression in Endometrial Cancers

    Lee, Kyung Eun

    2013-01-01

    O6-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein, the loss of MGMT expression was commonly known due to hypermethylation of CpG islands in its promoter region. Overexpression of p53 protein may be associated with downregulated MGMT expression in brain tumors. The aims of this study were to investigate the role of MGMT expression loss and its correlation with p53 overexpression in endometrial cancers. MGMT and p53 expression was examined in formalin-fixed, paraffin-embedded tissues from 36 endometrial cancer cases using immnunohistochemical staining. The loss of MGMT expression was detected in 11 (30.6%) out of the 36 endometrial cancers and p53 immunoreactivity was detected in 23 (63.9%) out of the 36 endometrial cancers. Ten (90.9%) of the 11 cases with negative MGMT immunoreactivity showed positive p53 expression, so the loss of MGMT expression was significantly associated with the p53 overexpression (P=0.03). These findings suggest that the loss of MGMT expression may be one of factors capable of p53 overexpression in endometrial cancer. Further studies are needed to define the relation between MGMT and p53 for examining the mechanisms of tissue-specific MGMT expression. PMID:25337565

  18. Transcriptional Activation by Wild-Type But Not Transforming Mutants of the p53 Anti-Oncogene

    Raycroft, Loretta; Wu, Hongyun; Lozano, Guillermina

    1990-01-01

    The protein encoded by the wild-type p53 proto-oncogene has been shown to suppress transformation, whereas certain mutations that alter p53 become transformation competent. Fusion proteins between p53 and the GAL4 DNA binding domain were made to anchor p53 to a DNA target sequence and to allow measurement of transcriptional activation of a reporter plasmid. The wild-type p53 stimulated transcription in this assay, but two transforming mutations in p53 were unable to act as transcriptional act...

  19. The Expression of p53 and Cox-2 in Basal Cell Carcinoma, Squamous Cell Carcinoma and Actinic Keratosis Cases

    Ülker KARAGECE YALÇIN

    2012-05-01

    Full Text Available Objective: The aim of this study was to investigate p53 and COX-2 expressions in basal cell carcinoma, squamous cell carcinoma and actinic keratoses, and to determine a possible relationship.Material and Method: 50 basal cell carcinoma, 45 squamous cell carcinoma and 45 actinic keratosis cases were evaluated. The type of tumor in basal cell carcinoma and tumor differentiation in squamous cell carcinoma were noted and the paraffin block that best represented the tumor was chosen. Immunostaining by p53 and COX-2 was performed on sections of the paraffin blocks.Results: p53 expression was observed in 98% of basal cell carcinoma, 88.9% of squamous cell carcinoma and all actinic keratosis cases. p53 expression was also noted in non-dysplastic appearing epithelium in actinic keratosis cases. COX-2 expression was seen in 90, 100 and 88.9% of the basal cell carcinoma, squamous cell carcinoma and actinic keratosis groups, respectively. Skin appendages, inflammatory cells and vascular structures were also stained by COX-2 besides tumor tissue. COX-2 expression increased by the p53 expression increase in basal cell carcinoma and squamous cell carcinoma. p53 and COX-2 expressions were not related in terms of tumor type in the BCC and were not related in terms of differentiation in SCC.Conclusion: The existence of p53 expression in actinic keratosis cases has supported the idea that p53 plays a role in the early steps of carcinogenesis in skin cancers. The fact that the expression of COX-2 increases in line with the increase of p53 expression in basal cell carcinoma and squamous cell carcinoma cases indicates that COX-2 expression may be affected by p53

  20. Potential role and chronology of abnormal expression of the Deleted in Colon Cancer (DCC) and the p53 proteins in the development of gastric cancer

    Loss of activity of tumor suppressor genes is considered a fundamental step in a genetic model of carcinogenesis. Altered expression of the p53 and the Deleted in Colon Cancer (DCC) proteins has been described in gastric cancer and this event may have a role in the development of the disease. According to this hypothesis, we investigated the p53 and the DCC proteins expression in different stages of gastric carcinomas. An immunohistochemical analysis for detection of p53 and DCC proteins expression was performed in tumor tissue samples of patients with UICC stage I and II gastric cancer. For the purpose of the analysis, the staining results were related to the pathologic data and compared between stage categories. Ninety-four cases of gastric cancer were analyzed. Disease stage categories were pT1N0 in 23 cases, pT2N0 in 20 cases, pT3N0 in 20 cases and pT1-3 with nodal involvment in 31 cases. Stage pT1-2N0 tumors maintained a positive DCC expression while it was abolished in pT3N0 tumors (p <.001). A significant higher proportion of patients with N2 nodal involvement showed DCC negative tumors. In muscular-invading tumors (pT2-3N0) the majority of cases showed p53 overexpression, whereas a significantly higher proportion of cases confined into the mucosa (pT1N0) showed p53 negative tumors. Also, a higher frequency of p53 overexpression was detected in cases with N1 and N2 metastatic lymphnodal involvement. Altered expression of both DCC and p53 proteins is detectable in gastric carcinomas. It seems that loss of wild-type p53 gene function and consequent p53 overexpression may be involved in early stages of tumor progression while DCC abnormalities are a late event

  1. TP53 Codon 72 Polymorphism and P53 Protein Expression in Colorectal Cancer Specimens in Isfahan

    Mehdi Nikbahkt Dastjerdi

    2011-02-01

    Full Text Available The TP53 tumor suppressor gene plays important roles in genomic stability. A common polymorphism at codon 72 of TP53 gene has been associated with increased risk for many human cancers. The p53 protein is expressed in colorectal cancer, but the reported prevalence of its expression varies widely. In the present study, the p53 protein expression in different genotypes of its codon 72 , was investigated. We undertook a case-control study on 250 controls and 250 paraffin block specimens of sporadic colorectal adenocarcinomas from the city of Isfahan. PCR amplification of TP53 codon 72 polymorphism: TP53 codon 72 genotypes were detected by PCR using specific primer pairs for amplifying the proline or the arginine Alleles. The PCR reaction was done separately for each of the two polymorphic variants. The amplified products were subjected to electrophoresis on 1% agarose gel in 1× TBE buffer and visualized on a transilluminator using ethidium bromide. Immunohistochemical Staining: We evaluated the expression patterns of p53 protein, as potential prognostic marker in colorectal cancer specimens by immunohistochemical staining. Statistical analyses: The χ2-test was used to assess the significance of any difference in the prevalence of TP53 codon 72 polymorphism between colorectal cancer patients and controls. The odds ratio and 95% CI (confidence intervals was used as a measure of the strength of the association. Statistical significance level was set to P≤0.05. In control samples, the genotype distribution for TP53 polymorphism showed 30.4%, 45.2% and 24.4% for the arginine/arginine, arginine/proline and proline/proline genotypes, respectively. Allelic frequencies corresponded to 0.663 for the arginine allele and 0.338 for the proline allele. In the cancer group 38.8% of the cases were arginine/arginine, 40.4% were arginine/proline and 20.8% were proline/proline. The corresponding frequencies were 0.590 for the arginine allele and 0.410 for the

  2. p53在乳腺癌中的表达意义及5-氮杂脱氧胞苷对 p53的调控作用%Expression of p53 in breast cancer and regulatory effects of 5-aza-2′-deoxycytidine on p53

    赖静; 管晓翔; 顾军; 许晶; 吴波; 张文文; 聂伟伟; 宋伟; 汪泽兴; 黄桂春

    2014-01-01

    目的: p53基因作为重要的抑癌基因,具有抑制肿瘤细胞增长、阻滞细胞周期及促进凋亡的作用,然而其在乳腺癌发生发展中的机制还有待进一步研究。文中研究p53在乳腺癌中的表达及其与临床病理参数的关系,进一步研究5-氮杂脱氧胞苷(5-aza-2′-deoxycytidine )在乳腺癌细胞中对p53表达调控的影响。方法采用免疫组化法检测组织芯片中80例乳腺癌组织及其癌旁正常组织中p53蛋白的表达情况,进一步用半定量RT-PCR及Western blot 法检测乳腺癌细胞中p53的表达及5-氮杂脱氧胞苷对p53表达的影响。结果①p53在乳腺癌组织中的阳性表达率为41.25%,明显高于正常乳腺组织(22.5%),差异有统计学意义(P<0.01)。②p53的表达与乳腺癌病理分级、乳腺癌患者的年龄、临床分期及淋巴结转移差异无统计学意义( P>0.05)。③在乳腺癌细胞MCF-7中,p53 mRNA及蛋白表达均呈低表达状态;在5-氮杂脱氧胞苷作用后,其表达均上调。结论 p53在乳腺癌组织中高表达,可能在乳腺癌的发生发展中起重要的作用。5-氮杂脱氧胞苷可诱导p53高表达,使其发挥抑癌基因作用,从而为治疗p53低表达乳腺癌药物的研发提供依据。%Objective Tumor suppressor gene p53 can inhibit tumor cell growth, arrest cell cycle, and promote apoptosis.Howev-er, the effects of p53 on the pathogenesis of breast cancer have not been fully elucidated.The aim of this study was to explore the expression of p53 protein and the correlation with clinical pathologic features in breast cancer.Furthermore, the regulatory effects of 5-aza-2′-deoxycyti-dine on p53 in breast cancer cell line were also studied. Methods The expression of p53 protein in 80 cases of breast cancer and normal and adjacent tissue were determined by the immunohistochemical staining .The expressions of p53 mRNA and p53 protein in breast cancer

  3. Expression of p53 in the Tumor and Oral Epithelium in Patients with Cancer of Mouth and Pharynx

    Santos, Fabiane Dittrich

    2011-01-01

    Full Text Available Introduction: Expressive percent of patients with oral and oral pharynx carcinomas presents with overexpression of protein p53 induced by tobacco, alcohol and radiotherapy. Objective: To describe the p53 expression in areas of the normal mucosa adjacent to the tumor and in mouth and pharynx carcinomas. Method: Prospective study with clinical follow-up of one year of 24 patients with oral and oral pharynx spinocellular carcinoma. We performed biopsies in the neoplasm and areas of the normal mucosa adjacent to the tumor, before and 9 months following radiotherapy and an immunohistochemical study of p53 expression. Results: Before radiotherapy, there was a change to the p53 expression in 20 out of the 24 biopsies made in the neoplasm and in 14 in those of normal mucosa adjacent to the tumor. Eleven patients died 1 year before clinical follow-up. From the 2 initial patients with increase of p53 after radiotherapy it remained increased in 7 in the neoplasm region and in 6 in the normal mucosa regions. We noticed association of p53 with smoking and tumor stage (p < 5%, but not with the degree of cellular differentiation and alcoholism. Conclusion: The increase to the p53 expression was viewed both in the neoplasm region and in the normal mucosa in most patients with oral and oral pharynx carcinoma before and after radiotherapy. There was a statistically significant correlation of the p53 expression with smoking and neoplasm stage.

  4. Correlation of p53 over-expression and alteration in p53 gene detected by polymerase chain reaction-single strand conformation polymorphism in adenocarcinoma of gastric cancer patients from India

    Sajjad Karim; Arif Ali

    2009-01-01

    AIM: To study the alterations in p53 gene among Indian gastric cancer patients and to correlate them with the various clinicopathological parameters.METHODS: A total of 103 gastric cancer patients were included in this study. The p53 alterations were studied by both immunohistochemical method as well as polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) analysis. We only studied four (exon 5, 6, 7, and 8) of the 11 p53 exons. The alterations in p53 were also correlated with respect to various clinicopathological parameters.RESULTS: Among 103 cases, p53 over-expression and alteration were detected in 37 (35.92%) and 19 (18.44%) cases, respectively. Most of the p53 alterations were found at exon 5 (31.54%), followed by exon 6 (26.31%), exon 7 (21.04%) and exon 8 (21.04%). A significant correlation of p53 overexpression was found with p53 alteration ( P = 0.000).Concordance between p53 alteration (as detected by SSCP) and over-expression [as detected by immunohistochemistry (IHC)] was found in 75% cases.We found that IHC-positive/SSCP-negative cases accounted for 21% of cases and IHC-negative/SSCPpositive cases accounted for remaining 4% cases.CONCLUSION: Our results show that p53 gene mutations are significantly correlated with p53 protein over-expression, with 75% concordance in overexpression and alteration in the p53 gene, but 25% disconcordance also cautions against the assumption that p53 over-expression is always associated with a gene mutation. There may be other mechanisms responsible for stabilization and accumulation of p53 protein with no evidence of gene mutation that reflect an accumulation of a non-mutated protein, or a false negative SSCP result.

  5. Expression of p53, Bax and Bcl-2 proteins in hepatocytes in non-alcoholic fatty liver disease

    Anatol Panasiuk; Janusz Dzieciol; Bozena Panasiuk; Danuta Prokopowicz

    2006-01-01

    AIM: To analyze the protein expression essential for apoptosis in liver steatosis.METHODS: The expression of proapoptotic proteinsp53, Bax, and antiapoptotic Bcl-2 in hepatocytes with steatosis (SH) and without steatosis (NSH) was evaluated in 84 patients at various stages of non-alcoholic fatty liver disease (NAFLD).RESULTS: Immunohistochemical staining of liver tissue showed the activation of p53 protein in SH and NSH with increased liver steatosis, diminished Bcl-2 and slightly decreased Bax protein. Positive correlation was found between the stage of liver steatosis with p53 expression in SH (r = 0.54, P < 0.01) and NSH (r = 0.49,P < 0.01).The antiapoptotic protein Bcl-2 was diminished together with the advancement of liver steatosis, especially in non-steatosed hepatocytes (r =0.43, P < 001).CONCLUSION: Apoptosis is one of the most important mechanisms leading to hepatocyte elimination in NAFLD. The intensification of inflammation in NAFLD induces proapoptotic protein p53 with the inhibition of antiapoptotic Bcl-2.

  6. p53 protein expression in corneal squamous cell carcinomas of dogs

    Lucas Bahdour Cossi

    2015-06-01

    Full Text Available Ocular tumors play an increasing concern in veterinary ophthalmology. Corneal squamous cell carcinoma is unfrequent in dogs, and by this way it has little studies. Studies that investigated the carcinogenesis mechanisms wich could help to the development of ocular squamous cell carcinoma (SCC in dog are rare. The aim of this work was to identify by immunohistochemical techniques, the p53 protein expression in the spontaneous dog corneal SCC. For this work, were used five cases of corneal SCC and one case of actinic keratitis. The sections were obtained from paraffin-wax blocks and submitted to histopathological and immunohistochemical analysis. All the six samples showed immunolabeling to cytokeratin and p53 protein. These results support the conclusions that the immunoreactivity of p53 protein by immunohistochemistry is present in canine corneal SCC suppporting its role in carcinogenesis of this tumor, but not provides prognostic indicators in cases of SCC corneal in dog; and can be a association of exposure to solar radiation with the possible mutation of the TP53 gene.

  7. Over-expression of tumour suppressor gene p53 in laryngeal squamous cell carcinomas and its prognostic significance.

    Salam, M A; Crocker, J; Morris, A

    1995-02-01

    p53 is a nuclear phosphoprotein which acts as a tumour suppressor factor, regulating cell growth and division. Mutations in the p53 gene appear to be the most common genetic alterations in human cancer. The aim of this study was to investigate p53 expression in laryngeal squamous cell carcinomas and to assess its role as a marker of prognostic significance. Using immunohistochemical staining techniques, a series of laryngeal carcinomas (n = 87) were examined for expression of the mutant form of p53 phosphoprotein using the monoclonal antibody PAB 1801. p53 over-expression was noted in 50 biopsies of laryngeal carcinomas (57.5%) but not in any of the non-neoplastic laryngeal mucosa which were used as the control. There was no statistical correlation between p53 immunoreactivity and the clinicopathological parameters of the cancers including: site of tumour, TNM staging, differentiation grading and tumour recurrence. These findings indicate that p53 expression is strongly associated with carcinoma cells and not with normal cells in the larynx. However, p53 expression is probably unrelated to the biological aggressiveness of these tumours. PMID:7788934

  8. Wild-type alternatively spliced p53: binding to DNA and interaction with the major p53 protein in vitro and in cells.

    Wu, Y.; Liu, Y; Lee, L.(Department of Physics, Yale University, New Haven, CT, USA); Miner, Z; Kulesz-Martin, M

    1994-01-01

    A p53 variant protein (p53as) generated from alternatively spliced p53 RNA is expressed in normal and malignant mouse cells and tissues, and p53as antigen activity is preferentially associated with the G2 phase of the cell cycle, suggesting that p53as and p53 protein may have distinct properties. Using p53as and p53 proteins translated in vitro, we now provide evidence that p53as protein has efficient sequence-specific DNA-binding ability. DNA binding by p53 protein is inefficient in comparis...

  9. Amplification of Mdmx (or Mdm4) directly contributes to tumor formation by inhibiting p53 tumor suppressor activity

    Danovi, Davide; Meulmeester, Erik; Pasini, Diego;

    2004-01-01

    ). Furthermore, the human Mdmx ortholog, Hdmx, was found to be overexpressed in a significant percentage of various human tumors and amplified in 5% of primary breast tumors, all of which retained wild-type p53. Hdmx was also amplified and highly expressed in MCF-7, a breast cancer cell line harboring wild......-type p53, and interfering RNA-mediated reduction of Hdmx markedly inhibited the growth potential of these cells in a p53-dependent manner. Together, these results make Hdmx a new putative drug target for cancer therapy.......Human tumors are believed to harbor a disabled p53 tumor suppressor pathway, either through direct mutation of the p53 gene or through aberrant expression of proteins acting in the p53 pathway, such as p14(ARF) or Mdm2. A role for Mdmx (or Mdm4) as a key negative regulator of p53 function in vivo...

  10. 贲门癌端粒酶活性表达及与p53基因突变关系的研究%Relationship of telomerase activity and p53 gene mutation in cardiac cancer

    Jingruo li; Mengquan li; Jiangtao Li; Juntao Bao; Yunhang Zhang

    2007-01-01

    Objective: To study the relationship of the telomerase activity and the p53 gene mutation in cardiac cancer.Methods: Telomerase activity and the p53 gene mutation were detected in 46 case of cardiac cancer, peri-cancerous and 30 case of normal mucosa by TRAP-ELISA and PCR-SSCP. Results: The rate of expression of telomerase activity in cardiac cancer, peri-cancerous and normal mucosa were 82.61% (38/46), 43.48% (20/46) and 13.33% (4/30) respectively. The rate of Exon5→8 of p53 gene mutation were 39.13% (18/46), 4.35% (2/46) and 0.00% respectively. There was significant differ ence between group cancer and without cancer (P < 0.01). Mean of (A) value of telomerase is 1.89 ± 0.41 in cancer group and were 1.49 ± 0.43, 0.54 ± 0.45 respectively in peri-canvcerous and normal mucosa, there were significant differences in cancer group and group of without cancer (P < 0.05). The rate of p53 gene mutations in group of expression of telomerase activity was 44.74% (17/38), and 12.50% (1/8) in without expression of telomerase activity. There were significant differences between the two groups. Conclusion: The rate of expression of telomerase activity and mean of (A) value of telomerase in cardiac cancer were obviously higher than without cancer, which indicating telomerase activity was closely related with the occurrence of cardiac cancer. P53 gene mutation in cardiac cancer were higher than the tissue of without cancer, and the rate of p53 gene mutation in telomerase activity were obviously higher than the group of without cancer. This shows the p53 gene mutation can loss of function of suppressing cancer and prompt telomerase activity and cause the cardiac cancer.