WorldWideScience

Sample records for human cancers p53

  1. Urodele p53 tolerates amino acid changes found in p53 variants linked to human cancer

    Directory of Open Access Journals (Sweden)

    Villiard Éric

    2007-09-01

    Full Text Available Abstract Background Urodele amphibians like the axolotl are unique among vertebrates in their ability to regenerate and their resistance to develop cancers. It is unknown whether these traits are linked at the molecular level. Results Blocking p53 signaling in axolotls using the p53 inhibitor, pifithrin-α, inhibited limb regeneration and the expression of p53 target genes such as Mdm2 and Gadd45, suggesting a link between tumor suppression and regeneration. To understand this relationship we cloned the p53 gene from axolotl. When comparing its sequence with p53 from other organisms, and more specifically human we observed multiple amino acids changes found in human tumors. Phylogenetic analysis of p53 protein sequences from various species is in general agreement with standard vertebrate phylogeny; however, both mice-like rodents and teleost fishes are fast evolving. This leads to long branch attraction resulting in an artefactual basal emergence of these groups in the phylogenetic tree. It is tempting to assume a correlation between certain life style traits (e.g. lifespan and the evolutionary rate of the corresponding p53 sequences. Functional assays of the axolotl p53 in human or axolotl cells using p53 promoter reporters demonstrated a temperature sensitivity (ts, which was further confirmed by performing colony assays at 37°C. In addition, axolotl p53 was capable of efficient transactivation at the Hmd2 promoter but has moderate activity at the p21 promoter. Endogenous axolotl p53 was activated following UV irradiation (100 j/m2 or treatment with an alkylating agent as measured using serine 15 phosphorylation and the expression of the endogenous p53 target Gadd45. Conclusion Urodele p53 may play a role in regeneration and has evolved to contain multiple amino acid changes predicted to render the human protein defective in tumor suppression. Some of these mutations were probably selected to maintain p53 activity at low temperature. However

  2. Comparison of Nuclear Accumulation of p53 Protein with Mutations in the p53 Gene of Human Breast Cancer Tissues

    Institute of Scientific and Technical Information of China (English)

    王萱仪; 查小明; 武正炎; 范萍

    2001-01-01

    Objective The objective was to compare nuclear accumulation of p53 protein with mutations in the p53 gene on the tissues of human breast cancer. Methods Fifty-four invasive ductal carcinomas of breast were analyzed by the method of polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) silver stain and strep-avidin-biotin-peroxidase complex (SABC) immunohistochemistry. Results A statistically significant association between the presence of p53 gene mutation and nuclear accumulation of p53 protein was found (P<0.01). 22 tumors that demonstrated p53 gene mutations showed nuclear accumulation of p53 protein, while only 9 (28%) showed nuclear accumulation of p53 protein in 32 tumors without p53 gene mutations. Both p53 mutation protein and p53 gene mutations were prevalent in steroid and progesterone receptors negative tumors (P<0.05). A statistically significant association was found between the nuclear accumulation of p53 protein and lymph node invasion (P<0.05), and between p53 gene mutations and lymph node invasion (P<0.05). p53 abnormalities might be associated with an aggressive phenotype in breast cancer. Conclusion The immunohistochemical detection of nuclear p53 protein accumulation is highly associated with p53 gene mutations in breast cancer tissues, and that this method is useful for rapid screening of p53 abnormalities. However, in order to avoid false positive reaction, the p53 gene mutations should be determined in cases slightly positive for p53 nuclear protein.

  3. p53 Family: Role of Protein Isoforms in Human Cancer

    Directory of Open Access Journals (Sweden)

    Jinxiong Wei

    2012-01-01

    Full Text Available TP53, TP63, and TP73 genes comprise the p53 family. Each gene produces protein isoforms through multiple mechanisms including extensive alternative mRNA splicing. Accumulating evidence shows that these isoforms play a critical role in the regulation of many biological processes in normal cells. Their abnormal expression contributes to tumorigenesis and has a profound effect on tumor response to curative therapy. This paper is an overview of isoform diversity in the p53 family and its role in cancer.

  4. COX-2 and p53 in human sinonasal cancer

    DEFF Research Database (Denmark)

    Holmila, Reetta; Cyr, Diane; Luce, Danièle

    2008-01-01

    the exposures and p53 accumulation were found; however, the p53 accumulation pattern (p = 0.062 for wood dust exposure) resembled that of COX-2 expression. In summary, our findings show increased COX-2 expression in SNC adenocarcinoma with wood dust exposure, suggesting a role for inflammatory components......The causal role of wood-dust exposure in sinonasal cancer (SNC) has been established in epidemiological studies, but the mechanisms of SNC carcinogenesis are still largely unknown. Increased amounts of COX-2 are found in both premalignant and malignant tissues, and experimental evidence link COX-2......; 41 for p53). Occupational histories and smoking habits were available for majority of the cases. Most of the adenocarcinoma cases with exposure history data had been exposed to wood dust at work in the past (88%, 14/16). For smokers, 63% (12/19) presented with SSC, whereas 64% (7/11) of nonsmokers...

  5. p53 acetylation enhances Taxol-induced apoptosis in human cancer cells.

    Science.gov (United States)

    Kim, Jae Hyeong; Yoon, Eun-Kyung; Chung, Hye-Jin; Park, Seong-Yeol; Hong, Kyeong-Man; Lee, Chang-Hun; Lee, Yeon-Su; Choi, Kyungho; Yang, Young; Kim, Kyungtae; Kim, In-Hoo

    2013-01-01

    Microtubule inhibitors (MTIs) such as Taxol have been used for treating various malignant tumors. Although MTIs have been known to induce cell death through mitotic arrest, other mechanisms can operate in MTI-induced cell death. Especially, the role of p53 in this process has been controversial for a long time. Here we investigated the function of p53 in Taxol-induced apoptosis using p53 wild type and p53 null cancer cell lines. p53 was upregulated upon Taxol treatment in p53 wild type cells and deletion of p53 diminished Taxol-induced apoptosis. p53 target proteins including MDM2, p21, BAX, and β-isoform of PUMA were also upregulated by Taxol in p53 wild type cells. Conversely, when the wild type p53 was re-introduced into two different p53 null cancer cell lines, Taxol-induced apoptosis was enhanced. Among post-translational modifications that affect p53 stability and function, p53 acetylation, rather than phosphorylation, increased significantly in Taxol-treated cells. When acetylation was enhanced by anti-Sirt1 siRNA or an HDAC inhibitor, Taxol-induced apoptosis was enhanced, which was not observed in p53 null cells. When an acetylation-defective mutant of p53 was re-introduced to p53 null cells, apoptosis was partially reduced compared to the re-introduction of the wild type p53. Thus, p53 plays a pro-apoptotic role in Taxol-induced apoptosis and acetylation of p53 contributes to this pro-apoptotic function in response to Taxol in several human cancer cell lines, suggesting that enhancing acetylation of p53 could have potential implication for increasing the sensitivity of cancer cells to Taxol.

  6. The p53 pathway in breast cancer

    OpenAIRE

    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...

  7. GROWTH INHIBITION OF HUMAN LARYNGEAL CANCER CELL WITH THE ADENOVIRUS-MEDIATED p53 GENE

    Institute of Scientific and Technical Information of China (English)

    WANG Qi; HAN De-min; WANG Wen-ge; WU Zu-ze; ZHANG Wei

    1999-01-01

    Objective: In most laryngeal cancers, the function of p53 gene is down regulated. To explore the potential use of p53 in gene therapy of laryngeal cancer, by introducing wild-type p53 into laryngeal cancer cell line via a recombinant adenoviral vector, Ad5CMV-p53 and analyzing its effects on cell and tumor growth. Methods: A human laryngeal cancer cell line Hep-2 was used.Recombinant cytomegalovirus-promoted adenoviruses containing human wild-type p53 cDNA was transiently introduced into Hep-2 line. The growth suppression of the Hep-2 cells and established s.c. squamous carcinoma model was examined. The p53 protein expression was detected using immunohistochemical analysis. Results: The transduction efficiencies of Hep-2 cell line were 100% at a multiplicity of 100 or greater. The p53 protein expression peaked on day 2 after infection and lasted far 5 days. In vitro growth assays revealed cell death following Ad5CMV-p53 infected. In vivo studies, Ad5CMV-p53 inhibited the tumorigenicity of Hep-2 cell, and in nude mice with established s.c. squamous carcinoma nodules showed that tumor volumes were significantly reduced in mice that received peritumoral infiltration of Ad5CMV-p53. Conclusion: Adenovirus-mediated antitumor therapy carrying the p53 gene is an efficient method to inhibit laryngeal cancer growth. Transfection of laryngeal cancer cells with the wild-type p53 gene via Ad5CMV-p53 is a potential novel approach to the therapy of laryngeal cancer.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  9. Mutations of p53 gene exons 4-8 in human esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    Li-Ya Li; Jin-Tian Tang; Li-Qun Jia; Pei-Wen Li

    2005-01-01

    AIM: To characterize the tumor suppressor gene p53 mutations in exon 4, esophageal cancer and adjacent noncancerous tissues.METHODS: We performed p53 (exons 4-8) gene mutation analysis on 24 surgically resected human esophageal cancer specimens by PCR, single-strand conformation polymorphism, and DNA sequencing. RESULTS: p53 gene mutations were detected in 9 of 22 (40.9%) esophageal cancer specimens and 10 of 17 (58.8%) adjacent non-cancerous tissues. Eight of sixteen (50.0%) point mutations detected were G-A transitions and 9 of 18 (50.0%) p53 gene mutations occurred in exon 4 in esophageal cancer specimens. Only 1 of 11 mutations detected was G-A transition and 4 of 11 (36.4%) p53 gene mutations occurred in exon 4 in adjacent non-cancerous tissues.CONCLUSION: Mutation of p53 gene in exon 4 may play an important role in development of esophageal cancer. The observation of p53 gene mutation in adjacent noncancerous tissues suggests that p53 gene mutation may be an early event in esophageal carcinogenesis. Some clinical factors, including age, sex, pre-operation therapy and location of tumors, do not influence p53 gene mutation rates.

  10. p53 and its isoforms in cancer

    OpenAIRE

    2007-01-01

    p53, p63 and p73 are members of the p53 gene family involved in development, differentiation and response to cellular stress. p53 gene is a transcription factor essential for the prevention of cancer formation. The p53 pathway is ubiquitously lost in human cancer either by p53 gene mutation (60% of cancers) or by lost of cell signalling upstream and downstream of p53 in the remaining cancers expressing WTp53 gene. As p53 pathway inactivation is a common denominator to all cancers, the underst...

  11. p53 Response to Ultrasound: Preliminary Observations in MCF7 Human Breast Cancer Cells

    Science.gov (United States)

    Burns, Janis M.; Campbell, Paul A.

    2011-09-01

    Mutated p53 can be found in approximately half of all human cancers. Strategies which seek to restore, or at least exercise a level of external control over, p53 functionality are thus potentially useful as adjuncts to therapy. Here, we report our preliminary measurements in this area, and demonstrate that short-burst pulsed ultrasound can indeed affect p53 activity. Specifically, we have observed that expression of the p53 protein can be regulated in the period immediately following low intensity short pulse (millisecond) ultrasound exposure, and that altered activity levels return to basal levels over a 24 hour period post-insonation.

  12. Oncogenic intra-p53 family member interactions in human cancers

    Directory of Open Access Journals (Sweden)

    Maria eFerraiuolo

    2016-03-01

    Full Text Available The p53 gene family members p53, p73 and p63 display several isoforms derived from the presence of internal promoters and alternative splicing events. They are structural homologues but hold peculiar functional properties. p53, p73 and p63 are tumor suppressor genes that promote differentiation, senescence and apoptosis. p53, unlike p73 and p63, is frequently mutated in cancer often displaying oncogenic gain of function (GOF activities correlated with the induction of proliferation, invasion, chemoresistance and genomic instability in cancer cells. These oncogenic functions are promoted either by the aberrant transcriptional cooperation of mutant p53 (mutp53 with transcription cofactors (e.g., NF-Y, E2F1, Vitamin D Receptor (VDR, Ets-1, NF-kB and YAP or by the interaction with the p53 family members, p73 and p63, determining their functional inactivation. The instauration of these aberrant transcriptional networks leads to increased cell growth, low activation of DNA damage response pathways (DNA damage response (DDR, DNA double-strand breaks (DSBs response, enhanced invasion and high chemoresistance to different conventional chemotherapeutic treatments. Several studies have clearly shown that different cancers harboring mutant p53 proteins exhibit a poor prognosis when compared to those carrying wild type p53 (wt-p53 protein. The interference of mutantp53/p73 and/or mutantp53/p63 interactions, thereby restoring p53, p73 and p63 tumor suppression functions, could be among the potential therapeutic strategies for the treatment of mutant p53 human cancers.

  13. CCR5 Expression Influences the Progression of Human Breast Cancer in a p53-dependent Manner

    OpenAIRE

    2003-01-01

    Chemokines are implicated in tumor pathogenesis, although it is unclear whether they affect human cancer progression positively or negatively. We found that activation of the chemokine receptor CCR5 regulates p53 transcriptional activity in breast cancer cells through pertussis toxin–, JAK2-, and p38 mitogen–activated protein kinase–dependent mechanisms. CCR5 blockade significantly enhanced proliferation of xenografts from tumor cells bearing wild-type p53, but did not affect proliferation...

  14. Dual regulation of energy metabolism by p53 in human cervix and breast cancer cells.

    Science.gov (United States)

    Hernández-Reséndiz, Ileana; Román-Rosales, Alejandra; García-Villa, Enríque; López-Macay, Ambar; Pineda, Erika; Saavedra, Emma; Gallardo-Pérez, Juan Carlos; Alvarez-Ríos, Elizabeth; Gariglio, Patricio; Moreno-Sánchez, Rafael; Rodríguez-Enríquez, Sara

    2015-12-01

    The role of p53 as modulator of OxPhos and glycolysis was analyzed in HeLa-L (cells containing negligible p53 protein levels) and HeLa-H (p53-overexpressing) human cervix cancer cells under normoxia and hypoxia. In normoxia, functional p53, mitochondrial enzyme contents, mitochondrial electrical potential (ΔΨm) and OxPhos flux increased in HeLa-H vs. HeLa-L cells; whereas their glycolytic enzyme contents and glycolysis flux were unchanged. OxPhos provided more than 70% of the cellular ATP and proliferation was abolished by anti-mitochondrial drugs in HeLa-H cells. In hypoxia, both cell proliferations were suppressed, but HeLa-H cells exhibited a significant decrease in OxPhos protein contents, ΔΨm and OxPhos flux. Although glycolytic function was also diminished vs. HeLa-L cells in hypoxia, glycolysis provided more than 60% of cellular ATP in HeLa-H cells. The energy metabolism phenotype of HeLa-H cells was reverted to that of HeLa-L cells by incubating with pifithrin-α, a p53-inhibitor. In normoxia, the energy metabolism phenotype of breast cancer MCF-7 cells was similar to that of HeLa-H cells, whereas p53shRNAMCF-7 cells resembled the HeLa-L cell phenotype. In hypoxia, autophagy proteins and lysosomes contents increased 2-5 times in HeLa-H cells suggesting mitophagy activation. These results indicated that under normoxia p53 up-regulated OxPhos without affecting glycolysis, whereas under hypoxia, p53 down-regulated both OxPhos (severely) and glycolysis (weakly). These p53 effects appeared mediated by the formation of p53-HIF-1α complexes. Therefore, p53 exerts a dual and contrasting regulatory role on cancer energy metabolism, depending on the O₂level.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Effects of p53 gene on drug resistance in human lung cancer cell lines

    Directory of Open Access Journals (Sweden)

    Wentao YUE

    2008-04-01

    Full Text Available Background and Objective Drug resistance of lung cancer cells is one of main factors which affect the outcome of chemotherapy. It has been reported that abnormal p53 gene is well assosiated with chemotherapy resistance of tumor cells. The aim of this study is to evaluate the effects of p53 gene on drug resistance in human lung cancer celllines,so as to provide foundation of choosing individual chemotherapy drugs in clinical treatment. Methods The expression vectors which contain p53cDNA and p53 antisense cDNA respectively were constructed and were confirmed by sequencing. Transfected the 801D, a human lung cancer cell line with recombined plasmids by lipofectin mediating.Several kinds of monoclone cell lines,pEGFP-801D、pEGFP-sense p53-801D(including sense p53,pEGFP-p53(RS-801D)、pEGFP-antisense p53-801D(including antisense p53,pEGFP-p53(AS-801D), which contained p53 odifferent status were obtained. Green fluorescence was observed through fluorescence microscopy. The extraneous gene was detected by PCR. MTT assay was taken to determine the drug resistance of each cell line to chemotherapy agents. Cell cycle and apoptosis induced by antitumor drugs were examined by flow cytometer. Results Extraneous sense p53 andantisense p53 were proved to be linked to plasmid respectively by sequencing.Green fluorescence was found in transfectedcell lines. The IC50 of pEGFP-p53(AS-801D cell line(0.26±0.09 μg/mL) to Cisplatin(DDP) decreased markedly compared with 801D(0.55±0.19 μg/mL,P﹤0.05)and pEGFP-801D(0.77±0.13μg/mL,P﹤0.05). The IC50 value of pEGFP-p53(RS-801D to DDP is 0.43±0.25 μg/mL,which is significantly lower than that of pEGFP-801D(P =0.000)but higher than that of pEGFP-p53(AS-801D(P <0.05. pEGFP-p53(RS-801D cell line showed a notably smaller value of IC50(2.34±0.43 ng/mL to Paclitaxel(TAX) than 801D(8.40±1.50 ng/mL, P <0.05)did. The IC50 value of pEGFPp53(RS-801D is lower than that of p

  17. p53 modulates the AMPK inhibitor compound C induced apoptosis in human skin cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shi-Wei [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Wu, Chun-Ying [Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Wang, Yen-Ting [Department of Medical Research and Education, Cheng Hsin General Hospital, Taipei, Taiwan (China); Kao, Jun-Kai [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Department of Pediatrics, Children' s Hospital, Changhua Christian Hospital, Changhua, Taiwan (China); Lin, Chi-Chen; Chang, Chia-Che; Mu, Szu-Wei; Chen, Yu-Yu [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chiu, Husan-Wen [Institute of Biotechnology, National Cheng-Kung University, Tainan, Taiwan (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan (China); Chang, Chuan-Hsun [Department of Surgical Oncology, Cheng Hsin General Hospital, Taipei, Taiwan (China); Department of Nutrition Therapy, Cheng Hsin General Hospital, Taipei, Taiwan (China); School of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan (China); Liang, Shu-Mei [Institute of Biotechnology, National Cheng-Kung University, Tainan, Taiwan (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan (China); Chen, Yi-Ju [Department of Dermatology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Huang, Jau-Ling [Department of Bioscience Technology, Chang Jung Christian University, Tainan, Taiwan (China); Shieh, Jeng-Jer, E-mail: shiehjj@vghtc.gov.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2013-02-15

    Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status. - Highlights: ► Compound C caused more apoptosis in p53 wildtype than p53-mutant skin cancer cells. ► Compound C can upregulate p53 expression and induce p53 activation. ► Compound C induced p53 effects were dependent on ROS induced DNA damage pathway. ► p53-knockdown attenuated compound C-induced apoptosis but not autophagy. ► Compound C-induced apoptosis in skin cancer cells was dependent on p53 status.

  18. [Effect of recombinant human p53 adenovirus (Ad-p53) combined with EGFR inhibitor gefitinib on the sensitivity of breast cancer MDA-MB-468 cells].

    Science.gov (United States)

    Wang, Xinzhao; Guan, Xiyun; Wang, Leilei; Xie, Li; Liu, Qi; Yu, Zhiyong

    2014-12-01

    To observe the impact of concurrent administration of recombinant human p53 adenovirus (Ad-p53) with EGFR inhibitor gefitinib on breast cancer MDA-MB-468 cells. MDA-MB-468 cells were treated with Ad-p53 and/or gefitinib. The effect of Ad-p53 and gefitinib on the growth of MDA-MB-468 cells was evaluated by MTT assay. Cell apoptosis was detected by flow cytometry. Western blot analysis was used to detect the alteration of p53,EGFR, phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway and apoptosis-related proteins. Ad-p53 combined with gefitinib was used in vivo to explore their effect on tumor xenograft in nude mice. Immunohistochemistry was used to detect the p53 expression in vivo. The MTT assay showed a stronger inhibitory effect of gefitinib on MDA-MB-468 cells infected with Ad-p53 than on the control cells. Cell apoptosis assay revealed that the apoptosis rates of MDA-MB-468 cells in vehicle-treated group, Ad-p53 group, gefitinib group, and combination group were 8.5%, 17.4%, 20.5% and 32.6%, respectively. The apoptosis rate of MDA-MB-468 cells in the combination group was higher than that in other groups (P MB-468 cells to gefitinib through down-regulation of the PI3K/Akt pathway. The apoptotic activity induced by this combination treatment might be regulated through caspase cascade.

  19. BAK overexpression mediates p53-independent apoptosis inducing effects on human gastric cancer cells

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2004-07-01

    Full Text Available Abstract Background BAK (Bcl-2 homologous antagonist/killer is a novel pro-apoptotic gene of the Bcl-2 family. It has been reported that gastric tumors have reduced BAK levels when compared with the normal mucosa. Moreover, mutations of the BAK gene have been identified in human gastrointestinal cancers, suggesting that a perturbation of BAK-mediated apoptosis may contribute to the pathogenesis of gastric cancer. In this study, we explored the therapeutic effects of gene transfer mediated elevations in BAK expression on human gastric cancer cells in vitro. Methods Eukaryotic expression vector for the BAK gene was constructed and transferred into gastric cancer cell lines, MKN-45 (wild-type p53 and MKN-28 (mutant-type p53. RT-PCR and Western Blotting detected cellular BAK gene expression. Cell growth activities were detected by MTT colorimetry and flow cytometry, while apoptosis was assayed by electronic microscopy and TUNEL. Western Blotting and colorimetry investigated cellular caspase-3 activities. Results BAK gene transfer could result in significant BAK overexpression, decreased in vitro growth, cell cycle G0/G1 arrest, and induced apoptosis in gastric cancer cells. In transferred cells, inactive caspase-3 precursor was cleaved into the active subunits p20 and p17, during BAK overexpression-induced apoptosis. In addition, this process occurred equally well in p53 wild-type (MKN-45, or in p53 mutant-type (MKN-28 gastric cancer cells. Conclusions The data presented suggests that overexpression of the BAK gene can lead to apoptosis of gastric cancer cells in vitro, which does not appear to be dependent on p53 status. The action mechanism of BAK mediated apoptosis correlates with activation of caspase-3. This could be served as a potential strategy for further development of gastric cancer therapies.

  20. Retrotransposition-Competent Human LINE-1 Induces Apoptosis in Cancer Cells With Intact p53

    Directory of Open Access Journals (Sweden)

    Abdelali Haoudi

    2004-01-01

    Full Text Available Retrotransposition of human LINE-1 (L1 element, a major representative non-LTR retrotransposon in the human genome, is known to be a source of insertional mutagenesis. However, nothing is known about effects of L1 retrotransposition on cell growth and differentiation. To investigate the potential for such biological effects and the impact that human L1 retrotransposition has upon cancer cell growth, we examined a panel of human L1 transformed cell lines following a complete retrotransposition process. The results demonstrated that transposition of L1 leads to the activation of the p53-mediated apoptotic pathway in human cancer cells that possess a wild-type p53. In addition, we found that inactivation of p53 in cells, where L1 was undergoing retrotransposition, inhibited the induction of apoptosis. This suggests an association between active retrotransposition and a competent p53 response in which induction of apoptosis is a major outcome. These data are consistent with a model in which human retrotransposition is sensed by the cell as a “genetic damaging event” and that massive retrotransposition triggers signaling pathways resulting in apoptosis.

  1. Relation between p53 (exon 7) mutation and p53 overexpression in human cervical cancers%宫颈癌p53外显子7突变与p53蛋白高表达的关系

    Institute of Scientific and Technical Information of China (English)

    张娜; 李惠芳; 常艳丽; 梁莎

    2001-01-01

    目的探讨宫颈癌p53外显子7突变与p53蛋白高表达的关系。方法采用免疫组织化学、聚合酶链反应(PCR)、限制性酶解片段长度多态性(RFLP)分析等方法对49例宫颈癌组织石蜡包埋标本中p53外显子7的突变与p53蛋白表达进行了检测。结果 p53外显子7的突变率8.2%(4/49)显著低于p53蛋白阳性率49.0%(24/49)(χ2=18.05,P<0.001);p53外显子7突变不一定p53蛋白阳性。结论 p53外显子7突变可能是部分宫颈癌变的一个重要因素;大部分宫颈癌可能主要由于高危人乳头状瘤病毒(HPV)感染后,通过E6/p53蛋白复合物的形成使p53蛋白失活所致。%Objective To investigate the relation between p53 (exon 7) mutations and p53 overexpression in human cervical cancer.Methods p53 (exon 7) mutation and p53 overexpression were examined by immunohistochemistry,polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis in 49 cases of cervical cancers on their paraffin-embedded tissue specimens.Results There was significant difference between p53 (exon 7) mutation 4/49 (8.2%) and p53 overexpression 24/49 (49.0%) in cervical cancer (χ2=18.05,P<0.001);not all cases of p53 mutation had p53 protein positive.Conclusion The p53 (exon 7) mutation is an important factor in part of cervical cancers,but anomalous structure and inactivation of p53 proteins caused by E6/p53 protein complex formed in high risk HPV infection are the significant cause of the greater part of cervical cancers.

  2. Aciculatin induces p53-dependent apoptosis via MDM2 depletion in human cancer cells in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Chin-Yu Lai

    Full Text Available Aciculatin, a natural compound extracted from the medicinal herb Chrysopogon aciculatus, shows potent anti-cancer potency. This study is the first to prove that aciculatin induces cell death in human cancer cells and HCT116 mouse xenografts due to G1 arrest and subsequent apoptosis. The primary reason for cell cycle arrest and cell death was p53 accumulation followed by increased p21 level, dephosphorylation of Rb protein, PUMA expression, and induction of apoptotic signals such as cleavage of caspase-9, caspase-3, and PARP. We demonstrated that p53 allele-null (-/- (p53-KO HCT116 cells were more resistant to aciculatin than cells with wild-type p53 (+/+. The same result was achieved by knocking down p53 with siRNA in p53 wild-type cells, indicating that p53 plays a crucial role in aciculatin-induced apoptosis. Although DNA damage is the most common event leading to p53 activation, we found only weak evidence of DNA damage after aciculatin treatment. Interestingly, the aciculatin-induced downregulation of MDM2, an important negative regulator of p53, contributed to p53 accumulation. The anti-cancer activity and importance of p53 after aciculatin treatment were also confirmed in the HCT116 xenograft models. Collectively, these results indicate that aciculatin treatment induces cell cycle arrest and apoptosis via inhibition of MDM2 expression, thereby inducing p53 accumulation without significant DNA damage and genome toxicity.

  3. A synthetic interaction screen identifies factors selectively required for proliferation and TERT transcription in p53-deficient human cancer cells.

    Directory of Open Access Journals (Sweden)

    Li Xie

    Full Text Available Numerous genetic and epigenetic alterations render cancer cells selectively dependent on specific genes and regulatory pathways, and represent potential vulnerabilities that can be therapeutically exploited. Here we describe an RNA interference (RNAi-based synthetic interaction screen to identify genes preferentially required for proliferation of p53-deficient (p53- human cancer cells. We find that compared to p53-competent (p53+ human cancer cell lines, diverse p53- human cancer cell lines are preferentially sensitive to loss of the transcription factor ETV1 and the DNA damage kinase ATR. In p53- cells, RNAi-mediated knockdown of ETV1 or ATR results in decreased expression of the telomerase catalytic subunit TERT leading to growth arrest, which can be reversed by ectopic TERT expression. Chromatin immunoprecipitation analysis reveals that ETV1 binds to a region downstream of the TERT transcriptional start-site in p53- but not p53+ cells. We find that the role of ATR is to phosphorylate and thereby stabilize ETV1. Our collective results identify a regulatory pathway involving ETV1, ATR, and TERT that is preferentially important for proliferation of diverse p53- cancer cells.

  4. Restoration of tumor suppressor miR-34 inhibits human p53-mutant gastric cancer tumorspheres

    Directory of Open Access Journals (Sweden)

    DeSano Jeffrey

    2008-09-01

    Full Text Available Abstract Background MicroRNAs (miRNAs, some of which function as oncogenes or tumor suppressor genes, are involved in carcinogenesis via regulating cell proliferation and/or cell death. MicroRNA miR-34 was recently found to be a direct target of p53, functioning downstream of the p53 pathway as a tumor suppressor. miR-34 targets Notch, HMGA2, and Bcl-2, genes involved in the self-renewal and survival of cancer stem cells. The role of miR-34 in gastric cancer has not been reported previously. In this study, we examined the effects of miR-34 restoration on p53-mutant human gastric cancer cells and potential target gene expression. Methods Human gastric cancer cells were transfected with miR-34 mimics or infected with the lentiviral miR-34-MIF expression system, and validated by miR-34 reporter assay using Bcl-2 3'UTR reporter. Potential target gene expression was assessed by Western blot for proteins, and by quantitative real-time RT-PCR for mRNAs. The effects of miR-34 restoration were assessed by cell growth assay, cell cycle analysis, caspase-3 activation, and cytotoxicity assay, as well as by tumorsphere formation and growth. Results Human gastric cancer Kato III cells with miR-34 restoration reduced the expression of target genes Bcl-2, Notch, and HMGA2. Bcl-2 3'UTR reporter assay showed that the transfected miR-34s were functional and confirmed that Bcl-2 is a direct target of miR-34. Restoration of miR-34 chemosensitized Kato III cells with a high level of Bcl-2, but not MKN-45 cells with a low level of Bcl-2. miR-34 impaired cell growth, accumulated the cells in G1 phase, increased caspase-3 activation, and, more significantly, inhibited tumorsphere formation and growth. Conclusion Our results demonstrate that in p53-deficient human gastric cancer cells, restoration of functional miR-34 inhibits cell growth and induces chemosensitization and apoptosis, indicating that miR-34 may restore p53 function. Restoration of miR-34 inhibits

  5. Depression of p53-independent Akt survival signals in human oral cancer cells bearing mutated p53 gene after exposure to high-LET radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Yosuke [Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Takahashi, Akihisa [Advanced Scientific Research Leader Development Unit, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511 (Japan); Kajihara, Atsuhisa; Yamakawa, Nobuhiro; Imai, Yuichiro [Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ota, Ichiro; Okamoto, Noritomo [Department of Otorhinolaryngology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Mori, Eiichiro [Department of Radiation Oncology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Noda, Taichi [Department of Dermatology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Furusawa, Yoshiya [Heavy-ion Radiobiology Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kirita, Tadaaki [Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ohnishi, Takeo, E-mail: tohnishi@naramed-u.ac.jp [Department of Radiation Oncology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer High-LET radiation induces efficiently apoptosis regardless of p53 gene status. Black-Right-Pointing-Pointer We examined whether high-LET radiation depresses the Akt-survival signals. Black-Right-Pointing-Pointer High-LET radiation depresses of survival signals even in the mp53 cancer cells. Black-Right-Pointing-Pointer High-LET radiation activates Caspase-9 through depression of survival signals. Black-Right-Pointing-Pointer High-LET radiation suppresses cell growth through depression of survival signals. -- Abstract: Although mutations and deletions in the p53 tumor suppressor gene lead to resistance to low linear energy transfer (LET) radiation, high-LET radiation efficiently induces cell lethality and apoptosis regardless of the p53 gene status in cancer cells. Recently, it has been suggested that the induction of p53-independent apoptosis takes place through the activation of Caspase-9 which results in the cleavage of Caspase-3 and poly (ADP-ribose) polymerase (PARP). This study was designed to examine if high-LET radiation depresses serine/threonine protein kinase B (PKB, also known as Akt) and Akt-related proteins. Human gingival cancer cells (Ca9-22 cells) harboring a mutated p53 (mp53) gene were irradiated with 2 Gy of X-rays or Fe-ion beams. The cellular contents of Akt-related proteins participating in cell survival signaling were analyzed with Western Blotting 1, 2, 3 and 6 h after irradiation. Cell cycle distributions after irradiation were assayed with flow cytometric analysis. Akt-related protein levels decreased when cells were irradiated with high-LET radiation. High-LET radiation increased G{sub 2}/M phase arrests and suppressed the progression of the cell cycle much more efficiently when compared to low-LET radiation. These results suggest that high-LET radiation enhances apoptosis through the activation of Caspase-3 and Caspase-9, and suppresses cell growth by suppressing Akt-related signaling, even in mp

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

    Institute of Scientific and Technical Information of China (English)

    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.

  7. rAd-p53 enhances the sensitivity of human gastric cancer cells to chemotherapy

    Institute of Scientific and Technical Information of China (English)

    Guang-Xia Chen; Li-Hong Zheng; Shi-Yu Liu; Xiao-Hua He

    2011-01-01

    AIM:To investigate potential antitumor effects of rAd-p53 by determining if it enhanced sensitivity of gastric cancer cells to chemotherapy.METHODS:Three gastric cancer cell lines with distinct levels of differentiation were treated with various doses of rAd-p53 alone,oxaliplatin (OXA) alone,or a combination of both.Cell growth was assessed with an 3-(4,5)-dimethylthiahiazo (-z-yl)-3,5-diphenytetrazoli-umromide assay and the expression levels of p53,Bax and Bcl-2 were determined by immunohistochemistry.The presence of apoptosis and the expression of cas-pase-3 were determined using flow cytometry.RESULTS:Treatment with rAd-p53 or OXA alone inhibited gastric cancer cell growth in a time- and dose-dependent manner;moreover,significant synergistic effects were observed when these treatments were combined.Immunohistochemical analysis demonstrated that treatment with rAd-p53 alone,OXA alone or combined treatment led to decreased Bcl-2 expression and increased Bax expression in gastric cancer cells.Furthermore,flow cytometry showed that rAd-p53 alone,OXA alone or combination treatment induced apoptosis of gastric cancer cells,which was accompanied by increased expression of caspase-3.CONCLUSION:rAd-p53 enhances the sensitivity of gastric cancer cells to chemotherapy by promoting apoptosis.Thus,our results suggest that p53 gene therapy combined with chemotherapy represents a novel avenue for gastric cancer treatment.

  8. Increasing drug resistance in human lung cancer cells by mutant-type p53 gene mediated by retrovirus

    Institute of Scientific and Technical Information of China (English)

    高振强; 高志萍; 刘喜富; 张涛

    1997-01-01

    Human mutant-type (mt) p53 cDNA was synthesized and cloned from human lung cancer cell line GL containing mt-p53 gene by using polymerase chain reaction (PCR). It was confirmed that the mt-p53 cDNA con-tained the complete coding sequence of p53 gene but mutated at codon 245 (G→T) and resulted in glycine to cysteine by sequencing analysis. The retroviral vector pD53M of the mt-p53 was constructed and introduced into the drug-sen-sitive human lung cancer cells GAO in which p53 gene did not mutate. The transfected GAO cells strongly expressed mutant-type p53 protein by immunohistochemistry, showing that pD53M vector could steadily express in GAO cells. The drug resistance to several anticancer agents of GAO cells infected by pD53M increased in varying degrees, with the highest increase of 4-fold, in vitro and in vivo. By quantitative PCR and flow cytometry (FCM) analyses, the expression of MDR1 gene and the activity of P-glycoprotein (Pgp) did not increase, the expression of MRP gene and the activity of m

  9. The human TLR innate immune gene family is differentially influenced by DNA stress and p53 status in cancer cells.

    Science.gov (United States)

    Shatz, Maria; Menendez, Daniel; Resnick, Michael A

    2012-08-15

    The transcription factor p53 regulates genes associated with a wide range of functions, including the Toll-like receptor (TLR) set of innate immunity genes, suggesting that p53 also modulates the human immune response. The TLR family comprises membrane glycoproteins that recognize pathogen-associated molecular patterns (PAMP) and mediate innate immune responses, and TLR agonists are being used as adjuvants in cancer treatments. Here, we show that doxorubicin, 5-fluorouracil, and UV and ionizing radiation elicit changes in TLR expression that are cell line- and damage-specific. Specifically, treatment-induced expression changes led to increased downstream cytokine expression in response to ligand stimulation. The effect of DNA stressors on TLR expression was mainly mediated by p53, and several p53 cancer-associated mutants dramatically altered the pattern of TLR gene expression. In all cell lines tested, TLR3 induction was p53-dependent, whereas induction of TLR9, the most stress-responsive family member, was less dependent on status of p53. In addition, each of the 10 members of the innate immune TLR gene family tested was differentially inducible. Our findings therefore show that the matrix of p53 status, chromosome stress, and responsiveness of individual TLRs should be considered in TLR-based cancer therapies.

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

    Institute of Scientific and Technical Information of China (English)

    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

  11. Mouse p53-Deficient Cancer Models as Platforms for Obtaining Genomic Predictors of Human Cancer Clinical Outcomes

    Science.gov (United States)

    Dueñas, Marta; Santos, Mirentxu; Aranda, Juan F.; Bielza, Concha; Martínez-Cruz, Ana B.; Lorz, Corina; Taron, Miquel; Ciruelos, Eva M.; Rodríguez-Peralto, José L.; Martín, Miguel; Larrañaga, Pedro; Dahabreh, Jubrail; Stathopoulos, George P.; Rosell, Rafael; Paramio, Jesús M.; García-Escudero, Ramón

    2012-01-01

    Mutations in the TP53 gene are very common in human cancers, and are associated with poor clinical outcome. Transgenic mouse models lacking the Trp53 gene or that express mutant Trp53 transgenes produce tumours with malignant features in many organs. We previously showed the transcriptome of a p53-deficient mouse skin carcinoma model to be similar to those of human cancers with TP53 mutations and associated with poor clinical outcomes. This report shows that much of the 682-gene signature of this murine skin carcinoma transcriptome is also present in breast and lung cancer mouse models in which p53 is inhibited. Further, we report validated gene-expression-based tests for predicting the clinical outcome of human breast and lung adenocarcinoma. It was found that human patients with cancer could be stratified based on the similarity of their transcriptome with the mouse skin carcinoma 682-gene signature. The results also provide new targets for the treatment of p53-defective tumours. PMID:22880004

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Pleurotus ostreatus inhibits proliferation of human breast and colon cancer cells through p53-dependent as well as p53-independent pathway

    Science.gov (United States)

    JEDINAK, ANDREJ; SLIVA, DANIEL

    2009-01-01

    In spite of the global consumption of mushrooms, only two epidemiological studies demonstrated an inverse correlation between mushroom intake and the risk of cancer. Therefore, in the present study we evaluated whether extracts from edible mushrooms Agaricus bisporus (portabella), Flammulina velutipes (enoki), Lentinula edodes (shiitake) and Pleurotus ostreatus (oyster) affect the growth of breast and colon cancer cells. Here, we identified as the most potent, P. ostreatus (oyster mushroom) which suppressed proliferation of breast cancer (MCF-7, MDA-MB-231) and colon cancer (HT-29, HCT-116) cells, without affecting proliferation of epithelial mammary MCF-10A and normal colon FHC cells. Flow cytometry revealed that the inhibition of cell proliferation by P. ostreatus was associated with the cell cycle arrest at G0/G1 phase in MCF-7 and HT-29 cells. Moreover, P. ostreatus induced the expression of the tumor suppressor p53 and cyclin-dependent kinase inhibitor p21(CIP1/WAF1), whereas inhibited the phosphorylation of retinoblastoma Rb protein in MCF-7 cells. In addition, P. ostreatus also up-regulated expression of p21 and inhibited Rb phosphorylation in HT-29 cells, suggesting that that P. ostreatus suppresses the proliferation of breast and colon cancer cells via p53-dependent as well as p53-independent pathway. In conclusion, our results indicated that the edible oyster mushroom has potential therapeutic/preventive effects on breast and colon cancer. PMID:19020765

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Restoration of p53 Expression in Human Cancer Cell Lines Upregulates the Expression of Notch1: Implications for Cancer Cell Fate Determination after Genotoxic Stress1

    Science.gov (United States)

    Alimirah, Fatouma; Panchanathan, Ravichandran; Davis, Francesca J; Chen, Jianming; Choubey, Divaker

    2007-01-01

    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, p53-mediated 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 p53-mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress. PMID:17534448

  16. Array-based genome-wide RNAi screening to identify shRNAs that enhance p53-related apoptosis in human cancer cells.

    Science.gov (United States)

    Idogawa, Masashi; Ohashi, Tomoko; Sugisaka, Jun; Sasaki, Yasushi; Suzuki, Hiromu; Tokino, Takashi

    2014-09-15

    p53 transduction is a potentially effective cancer therapy but does not result in a good therapeutic response in all human cancers due to resistance to apoptosis. To discover factors that overcome resistance to p53-induced apoptosis, we attempted to identify RNAi sequences that enhance p53-induced apoptosis. We screened a genome-wide lentiviral shRNA library in liver cancer Huh-7 and pancreatic cancer Panc-1 cells, both of which resist p53-induced apoptosis. After the infection of adenovirus expressing p53 or LacZ as a control, shRNA-treated populations were analyzed by microarray. We identified shRNAs that were significantly decreased in p53-infected cells compared with control cells. Among these shRNAs, shRNA-58335 was markedly decreased in both cancer cell lines tested. shRNA-58335 enhanced p53-related apoptosis in vitro and augmented the inhibitory effect of adenoviral p53 transduction on tumor growth in vivo. Furthermore, the enhanced apoptotic response by shRNA-58335 was also confirmed by treatment with PRIMA-1, which reactivates mutant p53, instead of adenoviral p53 transduction. We found that shRNA-58335 evokes the apoptotic response following p53 transduction or functional restoration of p53 with a small molecule drug in cancer cells resistant to p53-induced apoptosis. The combination of p53 restoration and RNAi-based drugs is expected to be a promising novel cancer therapy.

  17. Combined therapy of p53-wt and drug in an orthotopic multidrug-resistant human lung cancer model

    Institute of Scientific and Technical Information of China (English)

    高振强; 高志萍; 张涛

    1997-01-01

    Balb/c nu/nu mice were inoculated intratracheally with multidrug-resistant human lung cancer cells GLK containing p53 mutation at codon 245 and treated with intratracheal instillation of p53-wt retroviral vector (pDOR53W) to increase cell chemosensitivity, and then with intraperitoneal injection of doxorubicin. 30 d after tumor cell inoculation, 75% of the control mice showed macroscopic tumors in the lung. Sole pDOR53W suppressed GLK tumor formation in 68 % of mice; sole doxorubicin 33. 3 % , but the combination of pDOR53W and doxorubicin 88.9%. The exogenous p53 sequence was detected and confirmed in the tumor that grew after treatment with pDOR53W retroviral vector by PCR and Southern blot hybridization with p53 cDNA. These results suggested that di-rect administration of a retroviral vector expressing p53-wt combined with treatment of anticancer agent was an effec-tive therapeutic method for multidrug-resistant human lung cancer.

  18. Pro- and anti-apoptotic effects of p53 in cisplatin-treated human testicular cancer are cell context-dependent

    NARCIS (Netherlands)

    di Pietro, Alessandra; Koster, Roelof; Boersma-van Eck, Wytske; Dam, Wendy A.; Mulder, Nanno H.; Gietema, Jourik A.; de Vries, Elisabeth G. E.; de Jong, Steven

    2012-01-01

    In murine testicular cancer (TC) cells wild-type p53 contributes to sensitivity to DNA-damaging drugs in a dose-dependent way. In human TC, however, the role of wild-type p53 functionality in chemotherapeutic response remains elusive. We analyzed functionality of wild-type p53 in cisplatin sensitivi

  19. RPR-115135, a farnesyltransferase inhibitor, increases 5-FU- cytotoxicity in ten human colon cancer cell lines: role of p53.

    Science.gov (United States)

    Russo, Patrizia; Malacarne, Davide; Falugi, Carla; Trombino, Sonya; O'Connor, Patrick M

    2002-07-20

    A new non peptidic farnesyltransferase inhibitor, RPR-115135, in combination with 5-FU was studied in 10 human colon cancer cell lines (HCT-116, RKO, DLD-1, Colo-320, LoVo, SW-620, HT-29, HCT-15, Colo-205 and KM-12) carrying several mutations but well characterized for p53 and Ras status. We found that there was a slight tendency (not statistically significant) for the p53 inactivated cells to be less sensitive to 5-FU after 6 days continuous treatment. Simultaneous administration of RPR-115135 and 5-FU, at subtoxic concentrations, resulted in a synergistic enhancement of 5-FU cytotoxicity in the p53 wildtype cells (HCT-116, RKO, DLD-1, Colo-320, LoVo). In the p53 mutated cells (SW-620, HT-29, HCT-15, Colo-205, KM-12) the effect was very complicated. In HCT-15 the combination resulted in antagonism, in KM-12 in antagonism or in synergy (at different concentrations) and in SW-620, HT-29 and Colo-205 cells in synergy but only when 5-FU was administered at high concentrations. Growth inhibition could be accounted for on the basis of a specific cell cycle arrest phenotype (G2-M arrest), as assayed by flow cytometry, only in the p53 functioning cell lines. The combination RPR-115135 + 5-FU increases apoptotic events only in these cell lines. In the mutated cell lines no major alterations on cell cycle arrest phenotype and no induction of apoptosis was observed. Although RPR-115135 can potentiate the effect of 5-FU in cells in which p53 function is disrupted, these data suggest strongly that RPR-115135 significantly enhances the efficacy of 5-FU only when p53 is functioning.

  20. P53 mutations and cancer: a tight linkage.

    Science.gov (United States)

    Perri, Francesco; Pisconti, Salvatore; Della Vittoria Scarpati, Giuseppina

    2016-12-01

    P53 is often mutated in solid tumors, in fact, somatic changes involving the gene encoding for p53 (TP53) have been discovered in more than 50% of human malignancies and several data confirmed that p53 mutations represent an early event in cancerogenesis. Main p53 functions consist in cell cycle arrest, DNA repair, senescence and apoptosis induction in response to mutagenic stimuli, and, to exert those functions, p53 acts as transcriptional factor. Recent data have highlighted another very important role of p53, consisting in regulate cell metabolism and cell response to oxidative stress. Majority of tumor suppressor genes, such as adenomatous polyposis coli (APC), retinoblastoma-associated protein (RB) and Von-Hippel-Lindau (VHL) are inactivated by deletion or early truncation mutations in tumors, resulting in the decreased or loss of expression of their proteins. Differently, most p53 mutations in human cancer are missense mutations, which result in the production of full-length mutant p53 proteins. It has been reported that mutant p53 proteins and wild type p53 proteins often regulate same cellular biological processes with opposite effects. So, mutant p53 has been reported to supply the cancer cells of glucose and nutrients, and, to avoid reactive oxygen species (ROS) mediated damage during oxidative stress. These last features are able to render tumor cells resistant to ionizing radiations and chemotherapy. A future therapeutic approach in tumors bearing p53 mutations may be to deplete cancer cells of their energy reserves and antioxidants.

  1. In vivo comparison of transduction efficiency with recombinant adenovirus-mediated p53 in a human colon cancer mouse model by different delivery routes%rAd/p53不同给药途径治疗人类结肠癌荷瘤鼠模型p53导入效率的在体评价

    Institute of Scientific and Technical Information of China (English)

    Qi Xie; Biling Liang; ling Zhang; Qihua Yang; Xiongfei Gu; Jing Xu; Mingwang Chen

    2008-01-01

    Objective: To evaluate transduction efficiency with recombinant adenovirus-mediated p53 (rAd/p53) therapy in a human colon cancer mouse model by intra-tumoral injection and intra-arterial delivery. Methods: The tumor pieces of human colon cancer SW480 were implanted in the livers of 45 nude mice. These mice were administrated with rAd/p53 by intratu-moral injection and intra-arterial delivery. After 24 h, 48 h and 72 h rAd/p53 administration, 5 mice each group were killed with over anesthesia and their livers were removed. P53 expression and apoptosis of tumor and liver were assessed. Results: P53 expression and apoptosis of intratumoral administration group was higher than tail vein group and control group. Apoptosis and p53 expression of livers in three groups had no significant difference. Conclusion: p53 gene transduction efficiency and anticancer effect of tAd/p53 is much better by intra-tumoral injection than intra-arterial delivery.

  2. p53 as a target for the treatment of cancer.

    Science.gov (United States)

    Duffy, Michael J; Synnott, Naoise C; McGowan, Patricia M; Crown, John; O'Connor, Darran; Gallagher, William M

    2014-12-01

    TP53 (p53) is the most frequently mutated gene in cancer, being altered in approximately 50% of human malignancies. In most, if not all, cancers lacking mutation, wild-type (WT) p53 is inactivated by interaction with cellular (MDM2/MDM4) or viral proteins, leading to its degradation. Because of its near universal alteration in cancer, p53 is an attractive target for the development of new targeted therapies for this disease. However, until recently, p53 was widely regarded as ‘‘undruggable’’. This situation has now changed, as several compounds have become available that can restore wild-type properties to mutant p53 (e.g., PRIMA-1 and PRIMA-1MET). Other compounds are available that prevent the binding of MDM2/MDM4 to WT p53, thereby blocking its degradation (e.g., nutlins). Anti-mutant p53 compounds are potentially most useful in cancers with a high prevalence of p53 mutations. These include difficult-totreat tumors such as high grade serous ovarian cancer, triple-negative breast cancer and squamous lung cancer. MDM2/4 antagonists, on the other hand, are likely to be efficacious in malignancies in which MDM2 or MDM4 is overexpressed such as sarcomas, neuroblastomas and specific childhood leukemias. Presently, early clinical trials are ongoing evaluating the anti-mutant p53 agent, PRIMA-1MET, and specific MDM2–p53 nutlin antagonists.

  3. Gene p53 mutations, protein p53, and anti-p53 antibodies as biomarkers of cancer process.

    Science.gov (United States)

    Lutz, Waldemar; Nowakowska-Swirta, Ewa

    2002-01-01

    The finding that gene mutations and changes in their expression form the basis of cancer processes, has prompted molecular epidemiologists to use biomarkers for detecting damaged genes or proteins synthesized under their control in easily available cellular material or systemic liquids. Mutations in the suppressor gen p53 are thought to be essential for cancer development. This gen is one of the most important regulators of transcription, cellular cycle, DNA repair and apoptosis detected till now. Inactivation of gene p53 leads to uncontrolled cell divisions, and further to transformation of normal cells into the carcinous ones. Observations that mutations in gene p53 appear under conditions of occupational and environmental exposures to chemical and physical carcinogens, such as vinyl chloride, radon, or aflatoxin B1, have proved to be of enormous importance for the occupational and environmental health. Changes in expression of gene p53, and also its mutations, cause variations of cellular protein p53 concentration. Higher cellular protein p53 levels are associated with increased protein transfer to the extracellular liquid and to blood. It has been observed that increased blood serum protein p53 concentrations may have a prognostic value in early diagnosis of lung cancer. The results of a number of studies confirm that accumulation of a mutated form of protein p53, and presumably also large quantities of wild forms of that protein in the cells, may be a factor that triggers the production of anti-p53 antibodies. Statistical analysis showed that anti-p53 antibodies can be regarded as a specific biomarker of cancer process. The prevalence of anti-p53 antibodies correlated with the degree of cancer malignancy. The increased incidence of anti-p53 antibodies was also associated with higher frequency of mutations in gene p53. There are some reports confirming that anti-p53 antibodies emerging in blood serum in the subclinical phase of cancer development may be

  4. Human Monocyte-derived Dendritic Cells Pulsed with Wild-field name="type" p53 Protein Efficiently Induce Cytotoxic T-lymphocytes against p53 overexpressing Human Cancer Cells

    OpenAIRE

    德永, 尚之

    2005-01-01

    PURPOSE: Dendritic cells are the most potent antigen-presenting cells for initiating cellular immune responses. Dendritic cells are attractive immunoregulatory cells for cancer immunotherapy, and their efficacy has been investigated in clinical trials. The tumor suppressor gene p53 is pivotal in the regulation of apoptosis, and p53-based immunization is an attractive approach to cancer immunotherapy because of the accumulation of p53 protein in malignant but not in normal cells. It has been s...

  5. EFFECTS OF p53 GENE THERAPY COMBINED WITH CYCLOOXYGENASE-2 INHIBITOR ON CYCLOOXYGENASE-2 GENE EXPRESSION AND GROWTH INHIBITION OF HUMAN LUNG CANCER CELLS

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-Xia; LU Bin-Bin; WANG Teng; YIN Yong-Mei; DE Wei; SHU Yong-Qian

    2007-01-01

    Background Gene therapy by adenovirus-mediated wild-type p53 gene transfer has been shown to inhibit lung cancer growth in vitro, in animal models, and in human clinical trials. The antitumor effect of selective cyclooxygenase (COX)-2 inhibitors has been demonstrated in preclinical studies. However, no information is available on the effects of p53 gene therapy combined with selective COX-2 inhibitor on COX-2 gene expression and growth inhibition of human lung cancer cells. Methods We evaluated the effects of recombinant adenovirus-p53 (Ad-p53) gene therapy combined with selective COX-2 inhibitor on the proliferation, apoptosis, cell cycle arrest of human lung adenocarcinoma A549 cell line, and the effects of tumor suppressor exogenous wild type p53 on COX-2 gene expression. Results Ad-p53 gene therapy combined with selective COX-2 inhibitor celecoxib shows significant synergistic inhibition effects on the growth of human lung adenocarcinoma A549 cell line. Exogenous p53 gene can suppress COX-2 gene expression. Conclusions Significant synergistic inhibition effects of A549 cell line by the combined Ad-p53 and selective COX-2 inhibitor celecoxib may be achieved by enhancement of growth inhibition, apoptosis induction and suppression of COX-2 gene expression. This study provides first evidence that the administration of p53 gene therapy in combination with COX-2 inhibitors might be a new clinical strategy for the treatment or prevention of NSCLC.

  6. Human papilloma virus DNA and p53 mutation analysis on bladder washes in relation to clinical outcome of bladder cancer.

    NARCIS (Netherlands)

    Moonen, P.M.J.; Bakkers, J.M.J.E.; Kiemeney, L.A.L.M.; Schalken, J.A.; Melchers, W.J.G.; Witjes, J.A.

    2007-01-01

    OBJECTIVES: High-risk human papilloma virus (HPV) types stimulate degradation and deactivation of protein associated with the p53 tumour suppressor gene via the ubiquitin-dependent pathway. For a long time, changes of the p53 tumour suppressor gene have been correlated with poor clinical outcome in

  7. A platform for interrogating cancer-associated p53 alleles.

    Science.gov (United States)

    D'Brot, A; Kurtz, P; Regan, E; Jakubowski, B; Abrams, J M

    2017-01-12

    p53 is the most frequently mutated gene in human cancer. Compelling evidence argues that full transformation involves loss of growth suppression encoded by wild-type p53 together with poorly understood oncogenic activity encoded by missense mutations. Furthermore, distinguishing disease alleles from natural polymorphisms is an important clinical challenge. To interrogate the genetic activity of human p53 variants, we leveraged the Drosophila model as an in vivo platform. We engineered strains that replace the fly p53 gene with human alleles, producing a collection of stocks that are, in effect, 'humanized' for p53 variants. Like the fly counterpart, human p53 transcriptionally activated a biosensor and induced apoptosis after DNA damage. However, all humanized strains representing common alleles found in cancer patients failed to complement in these assays. Surprisingly, stimulus-dependent activation of hp53 occurred without stabilization, demonstrating that these two processes can be uncoupled. Like its fly counterpart, hp53 formed prominent nuclear foci in germline cells but cancer-associated p53 variants did not. Moreover, these same mutant alleles disrupted hp53 foci and inhibited biosensor activity, suggesting that these properties are functionally linked. Together these findings establish a functional platform for interrogating human p53 alleles and suggest that simple phenotypes could be used to stratify disease variants.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. p53 amplifies Toll-like receptor 5 response in human primary and cancer cells through interaction with multiple signal transduction pathways.

    Science.gov (United States)

    Shatz, Maria; Shats, Igor; Menendez, Daniel; Resnick, Michael A

    2015-07-10

    The p53 tumor suppressor regulates transcription of genes associated with diverse cellular functions including apoptosis, growth arrest, DNA repair and differentiation. Recently, we established that p53 can modulate expression of Toll-like receptor (TLR) innate immunity genes but the degree of cross-talk between p53 and TLR pathways remained unclear. Here, using gene expression profiling we characterize the global effect of p53 on the TLR5-mediated transcription in MCF7 cells. We found that combined activation of p53 and TLR5 pathways synergistically increases expression of over 200 genes, mostly associated with immunity and inflammation. The synergy was observed in several human cancer cells and primary lymphocytes. The p53-dependent amplification of transcriptional response to TLR5 activation required expression of NFκB subunit p65 and was mediated by several molecular mechanisms including increased phosphorylation of p38 MAP kinase, PI3K and STAT3 signaling. Additionally, p53 induction increased cytokine expression in response to TNFα, another activator of NFκB and MAP kinase pathways, suggesting a broad interaction between p53 and these signaling pathways. The expression of many synergistically induced genes is elevated in breast cancer patients responsive to chemotherapy. We suggest that p53's capacity to enhance immune response could be exploited to increase antitumor immunity and to improve cancer treatment.

  10. p53 amplifies Toll-like receptor 5 response in human primary and cancer cells through interaction with multiple signal transduction pathways

    Science.gov (United States)

    Shatz, Maria; Shats, Igor; Menendez, Daniel; Resnick, Michael A.

    2015-01-01

    The p53 tumor suppressor regulates transcription of genes associated with diverse cellular functions including apoptosis, growth arrest, DNA repair and differentiation. Recently, we established that p53 can modulate expression of Toll-like receptor (TLR) innate immunity genes but the degree of cross-talk between p53 and TLR pathways remained unclear. Here, using gene expression profiling we characterize the global effect of p53 on the TLR5-mediated transcription in MCF7 cells. We found that combined activation of p53 and TLR5 pathways synergistically increases expression of over 200 genes, mostly associated with immunity and inflammation. The synergy was observed in several human cancer cells and primary lymphocytes. The p53-dependent amplification of transcriptional response to TLR5 activation required expression of NFκB subunit p65 and was mediated by several molecular mechanisms including increased phosphorylation of p38 MAP kinase, PI3K and STAT3 signaling. Additionally, p53 induction increased cytokine expression in response to TNFα, another activator of NFκB and MAP kinase pathways, suggesting a broad interaction between p53 and these signaling pathways. The expression of many synergistically induced genes is elevated in breast cancer patients responsive to chemotherapy. We suggest that p53's capacity to enhance immune response could be exploited to increase antitumor immunity and to improve cancer treatment. PMID:26220208

  11. Deficiency in p53 is required for doxorubicin induced transcriptional activation of NF-κB target genes in human breast cancer

    Science.gov (United States)

    Dalmases, Alba; González, Irene; Menendez, Silvia; Arpí, Oriol; Corominas, Josep Maria; Servitja, Sonia; Tusquets, Ignasi; Chamizo, Cristina; Rincón, Raúl; Espinosa, Lluis; Bigas, Anna; Eroles, Pilar; Furriol, Jessica; Lluch, Anna; Rovira, Ana; Albanell, Joan; Rojo, Federico

    2014-01-01

    NF-κB has been linked to doxorubicin resistance in breast cancer patients. NF-κB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined; however its functional relevance at transcriptional level on NF-κB -dependent genes and the biological consequences are unclear. We studied NF-κB -dependent gene expression induced by doxorubicin in breast cancer cells and fresh human cancer specimens with different genetic backgrounds focusing on their p53 status. NF-κB -dependent signature of doxorubicin was identified by gene expression microarrays in breast cancer cells treated with doxorubicin and the IKKβ-inhibitor MLN120B, and confirmed ex vivo in human cancer samples. The association with p53 was functionally validated. Finally, NF-κB activation and p53 status was determined in a cohort of breast cancer patients treated with adjuvant doxorubicin-based chemotherapy. Doxorubicin treatment in the p53-mutated MDA-MB-231 cells resulted in NF NF-κB driven-gene transcription signature. Modulation of genes related with invasion, metastasis and chemoresistance (ICAM-1, CXCL1, TNFAIP3, IL8) were confirmed in additional doxorubicin-treated cell lines and fresh primary human breast tumors. In both systems, p53-defcient background correlated with the activation of the NF-κB -dependent signature. Furthermore, restoration of p53WT in the mutant p53 MDA-MB-231 cells impaired NF-κB driven transcription induced by doxorubicin. Moreover, a p53 deficient background and nuclear NF-κB /p65 in breast cancer patients correlated with reduced disease free-survival. This study supports that p53 deficiency is necessary for a doxorubicin driven NF-κB -response that limits doxorubicin cytotoxicity in breast cancer and is linked to an aggressive clinical behavior. PMID:24344116

  12. Targeting cancer stem cells with p53 modulators

    Science.gov (United States)

    Hayashi, Ryo; Appella, Ettore; Kopelovich, Levy; DeLeo, Albert B.

    2016-01-01

    Cancer stem cells (CSC) typically over-express aldehyde dehydrogenase (ALDH). Thus, ALDHbright tumor cells represent targets for developing novel cancer prevention/treatment interventions. Loss of p53 function is a common genetic event during cancer development wherein small molecular weight compounds (SMWC) that restore p53 function and reverse tumor growth have been identified. Here, we focused on two widely studied p53 SMWC, CP-31398 and PRIMA-1, to target ALDHbright CSC in human breast, endometrial and pancreas carcinoma cell lines expressing mutant or wild type (WT) p53. CP-31398 and PRIMA-1 significantly reduced CSC content and sphere formation by these cell lines in vitro. In addition, these agents were more effective in vitro against CSC compared to cisplatin and gemcitabine, two often-used chemotherapeutic agents. We also tested a combinatorial treatment in methylcholantrene (MCA)-treated mice consisting of p53 SMWC and p53-based vaccines. Yet using survival end-point analysis, no increased efficacy in the presence of either p53 SMWC alone or with vaccine compared to vaccine alone was observed. These results may be due, in part, to the presence of immune cells, such as activated lymphocytes expressing WT p53 at levels comparable to some tumor cells, wherein further increase of p53 expression by p53 SMWC may alter survival of these immune cells and negatively impact an effective immune response. Continuous exposure of mice to MCA may have also interfered with the action of these p53 SMWC, including potential direct interaction with MCA. Nonetheless, the effect of p53 SMWC on CSC and cancer treatment remains of great interest. PMID:27074569

  13. Expression and clinical significance of EZH2 and p53 protein in human prostate cancer%EZH2和p53蛋白在前列腺癌中的表达及其临床意义

    Institute of Scientific and Technical Information of China (English)

    李江; 邱雁; 邱梁

    2011-01-01

    Objective To explore the expression of EZH2 and p53 protein in primary prostate cancer (Pca) and its clinical significance.Methods High-throughput tissue microarray technique and immunohistochemistry was used to detect the expression of EZH2 and p53 protein in 48 human prostate cancer specimens without a history of chemo-radiation therapy and 15 cases of benign prostate hyperplasic (BPH) tissues. The pathological characteristics and the relationship of the expression of EZH2 and p53 protein in primary prostate cancer was analyzed. Results Immunohistochemical results showed that the positive rates of EZH2 and p53 protein in prostate cancer were 87.50 % (42/48) and 33.33 % (16/48), respectively, which were significantly higher than that in BPH tissues[13.33 % (2/15) and 0 (0/15)](x2=26.429, x2=5.058,P <0.05). The expression of EZH2 and p53 protein was significantly related to Gleason score, TNM stage (P <0.05), but not to age and serum prostate-specific antigen (PSA) level (P >0.05). The positive expression in patients with Gleason>6 was higher than that with Gleason≤6 (P <0.05). The positive expression in patients with T3-T4 stage was higher than that with T1-T2 stage (P <0.05). Spearman rank correlation showed a significantly positive correlation between EZH2 and p53 protein (r=0.294, P <0.05). Conclusion EZH2 and p53 protein may participate in the pathogenesis of prostate cancer. The overexpression of EZH2 and p53 protein could become an index for the evaluation of the level of malignancy and progression of prostate cancer.Furthermore, combining detection of EZH2 and p53 protein may provide a new theoretical basis for the treatment of prostate cancer.%目的 探讨EZH2和p53蛋白在前列腺癌组织中的表达及其临床意义。方法通过组织芯片技术,应用EnVision免疫组织化学法检测48例术前无放化疗史的前列腺癌标本和15例良性前列腺增生组织中EZH2、p53蛋白的表达情况,并分析EZH2和p53

  14. Cyclooxygenase-2 suppresses hypoxia-induced apoptosis via a combination of direct and indirect inhibition of p53 activity in a human prostate cancer cell line.

    Science.gov (United States)

    Liu, Xin-Hua; Kirschenbaum, Alexander; Yu, Kang; Yao, Shen; Levine, Alice C

    2005-02-04

    Although p53-inactivating mutations have been described in the majority of human cancers, their role in prostate cancer is controversial as mutations are uncommon, particularly in early lesions. p53 is activated by hypoxia and other stressors and is primarily regulated by the Mdm2 protein. Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the conversion of arachidonic acid to prostaglandins and other eicosanoids, is also induced by hypoxia. COX-2 and resultant prostaglandins increase tumor cell proliferation, resistance to apoptosis, and angiogenesis. Previous reports indicate a complex, reciprocal relationship between p53 and COX-2. To elucidate the effects of COX-2 on p53 in response to hypoxia, we transfected the COX-2 gene into the p53-positive, COX-2-negative MDA-PCa-2b human prostate cancer cell line. The expression of functional p53 and Mdm2 was compared in COX-2+ versus COX-2- cells under normoxic and hypoxic conditions. Our results demonstrated that hypoxia increases both COX-2 protein levels and p53 transcriptional activity in these cells. Forced expression of COX-2 increased tumor cell viability and decreased apoptosis in response to hypoxia. COX-2+ cells had increased Mdm2 phosphorylation in either normoxic or hypoxic conditions. Overexpression of COX-2 abrogated hypoxia-induced p53 phosphorylation and promoted the binding of p53 to Mdm2 protein in hypoxic cells. In addition, COX-2-expressing cells exhibited decreased hypoxia-induced nuclear accumulation of p53 protein. Finally, forced expression of COX-2 suppressed both basal and hypoxia-induced p53 transcriptional activity, and this effect was mimicked by the addition of PGE2 to wild-type cells. These results demonstrated a role for COX-2 in the suppression of hypoxia-induced p53 activity via both direct effects and indirect modulation of Mdm2 activity. These data imply that COX-2-positive prostate cancer cells can have impaired p53 function even in the presence of wild-type p53 and that p53

  15. Translational approaches targeting the p53 pathway for anti-cancer therapy

    OpenAIRE

    2012-01-01

    The p53 tumour suppressor blocks cancer development by triggering apoptosis or cellular senescence in response to oncogenic stress or DNA damage. Consequently, the p53 signalling pathway is virtually always inactivated in human cancer cells. This unifying feature has commenced tremendous efforts to develop p53-based anti-cancer therapies. Different strategies exist that are adapted to the mechanisms of p53 inactivation. In p53-mutated tumours, delivery of wild-type p53 by adenovirus-based gen...

  16. Adenovirus-mediated Transfer of p53 and p16 Inhibiting Proliferating Activity of Human Bladder Cancer Cell EJ in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    朱朝辉; 邢诗安; 林晨; 曾甫清; 鲁功成; 付明; 张雪艳; 梁萧; 吴旻

    2002-01-01

    Summary: To evaluate the effects of adenovirus (Ad)-mediated transfer of p53 and p16 on humanbladder cancer cells EJ, EJ were transfected with Ad-p53 and Ad-p16. Cell growth, morphologi-cal change, cell cycle, apoptosis were measured using MTT assay, flow gytometry, cloning forma-tion, immunocytochemical assays. Ad-p16 or Ad-p53 alone could inhibit the proliferating activityof EJ cells in vitro. Ad-p53 could induce apoptosis of partial EJ cells. G1 arrest was observed 72 hafter infection with Ad-p16, but apoptosis was not obvious. The transfer of Ad-p16 and Ad-p53could significantly inhibit the growth of EJ cells, decrease the cloning formation rate and induceapoptosis of large number of EJ cells. The occurrence time of subcutaneous tumor was delayed andthe tumor volume in 4 weeks was diminished by using Ad-p53 combined with Ad-p16 and the dif-ference was significant compared with using Ad-p53 or Ad-p16 alone. It was suggested that thetransfer of wild-type p53 and p16 could significantly inhibit the growth of human bladder cancer invitro and in vivo.

  17. Regulation of Drug Sensitivity by Functional Status of p53 in Human Prostate Cancer

    Science.gov (United States)

    2005-01-01

    containing 5% C0 2/95% air. Cell lines were free of Mycoplasnma Received 6/24/02; accepted 4/2/03. and fungi and were discarded after 3 months; new cell...cells expressing the prostate cancer cells. J. Clin. Investig., 105: 1261-1267, 2000. multidrug resistance-associated protein MRP. Anticancer Drugs, 8... Anticancer Drugs, 8: 125-140, 1997. stimulates sulfated estrogen transport by multidrug resistance protein 1. J. Biol. 25. Hipfner, D. R., Deeley, R. G. and

  18. Alterations of EGFR, p53 and PTEN that mimic changes found in basal-like breast cancer promote transformation of human mammary epithelial cells.

    Science.gov (United States)

    Pires, Maira M; Hopkins, Benjamin D; Saal, Lao H; Parsons, Ramon E

    2013-03-01

    Breast cancer can be classified into different molecular subtypes with varying clinical and pathological characteristics. The basal-like breast cancer subtype represents one of the most aggressive and lethal types of breast cancer, and due to poor mechanistic understanding, it lacks targeted therapy. Many basal-like breast cancer patient samples display alterations of established drivers of cancer development, including elevated expression of EGFR, p53 inactivating mutations and loss of expression of the tumor suppressor PTEN; however, their contribution to human basal-like breast cancer pathogenesis remains ill-defined. Using non-transformed human mammary epithelial cells, we set out to determine whether altering EGFR, p53 and PTEN in different combinations could contribute to basal-like breast cancer progression through transformation of cells. Altering PTEN in combination with either p53 or EGFR in contrast to any of the single alterations caused increased growth of transformed colonies in soft agar. Concomitantly modifying all three genes led to the highest rate of cellular proliferation and the greatest degree of anchorage-independent colony formation. Results from our effort to engineer a model of BBC expressing alterations of EGFR, p53 and PTEN suggest that these changes are cooperative and likely play a causal role in basal-like breast cancer pathogenesis. Consideration should be given to targeting EGFR and restoring p53 and PTEN signaling simultaneously as a strategy for treatment of this subtype of breast cancer.

  19. The collective nuclear migration of p53 and phosphorylated S473 of Akt during ellipticine-mediated apoptosis in human lung epithelial cancer cells.

    Science.gov (United States)

    Wang, Jing-Ping; Yu, Ya-Chu; Chen, Shih-Ping; Liang, Huan-Chang; Lin, Chia-Wei; Fang, Kang

    2015-09-01

    Topoisomerase II inhibitor ellipticine effectively suppressed the growth of human non-small-cell-lung-cancer (NSCLC) epithelial cells. Previously, we reported the drug activity was consummated through parallel nucleus migration of p53 and Akt in A549 cells. While inducing cell death, the drug activity was proved related to autophagy through phosphorylated Akt at S473. In addition, ellipticine induced cytotoxicity in p53-null H1299 cells with stable expression of ectopic p53. In this work, we further demonstrated that dominant-negative Akt (S473A) or p53 shRNA inhibited ellipticine-mediated translocalization of p53 and Akt and attenuated apoptotic cell death in A549 cells. The presence of p53 predates ellipticine-mediated apoptotic cell death, assists in nucleus translocation of phosphorylated Akt and activation of autophagy pathway. Growth inhibition through collaborating p53 and phosphorylated Akt(473) in lung epithelial cancer cells provided a new perspective of the topoisomerase inhibitor as an effective cancer therapy agent.

  20. Early apoptosis and cell death induced by ATX-S10Na ( Ⅱ)-mediated photodynamic therapy are Bax- and p53-dependent in human colon cancer cells

    Institute of Scientific and Technical Information of China (English)

    Makoto Mitsunaga; Akihito Tsubota; Kohichi Nariai; Yoshihisa Namiki; Makoto Sumi; Tetsuya Yoshikawa; Kiyotaka Fujise

    2007-01-01

    AIM: To investigate the roles of Bax and p53 proteins in photosensitivity of human colon cancer cells by using lysosome-localizing photosensitizer, ATX-S10Na (Ⅱ).METHODS: HCT116 human colon cancer cells and Bax-null or p53-null isogenic derivatives were irradiated with a diode laser. Early apoptosis and cell death in response to photodynamic therapy were determined by MTT assays, annexin V assays, transmission electron microscopy assays, caspase assays and western blotting.RESULTS: Induction of early apoptosis and cell death was Bax- and p53-dependent. Bax and p53 were required for caspase-dependent apoptosis. The levels of anti-apoptotic Bcl-2 family proteins, Bcl-2 and Bcl-XL,were decreased in Bax- and p53-independent manner.CONCLUSION: Our results indicate that early apoptosis and cell death of human colon cancer cells induced by photodynamic therapy with lysosome-localizingphotosensitizer ATX-S10Na (Ⅱ) are mediated by p53-Bax network and Iow levels of Bcl-2 and Bcl-XL proteins.Our results might help in formulating new therapeutic approaches in photedynamic therapy.

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

    OpenAIRE

    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 p5...

  2. The p53 Isoform Δ133p53β Promotes Cancer Stem Cell Potential

    Directory of Open Access Journals (Sweden)

    Nikola Arsic

    2015-04-01

    Full Text Available Cancer stem cells (CSC are responsible for cancer chemoresistance and metastasis formation. Here we report that Δ133p53β, a TP53 splice variant, enhanced cancer cell stemness in MCF-7 breast cancer cells, while its depletion reduced it. Δ133p53β stimulated the expression of the key pluripotency factors SOX2, OCT3/4, and NANOG. Similarly, in highly metastatic breast cancer cells, aggressiveness was coupled with enhanced CSC potential and Δ133p53β expression. Like in MCF-7 cells, SOX2, OCT3/4, and NANOG expression were positively regulated by Δ133p53β in these cells. Finally, treatment of MCF-7 cells with etoposide, a cytotoxic anti-cancer drug, increased CSC formation and SOX2, OCT3/4, and NANOG expression via Δ133p53, thus potentially increasing the risk of cancer recurrence. Our findings show that Δ133p53β supports CSC potential. Moreover, they indicate that the TP53 gene, which is considered a major tumor suppressor gene, also acts as an oncogene via the Δ133p53β isoform.

  3. Anticancer effect of xanthohumol induces growth inhibition and apoptosis of human liver cancer through NF-κB/p53-apoptosis signaling pathway

    OpenAIRE

    ZHAO, XIANGQIAN; Jiang, Kai; Liang, Bin; Huang, Xiaoqiang

    2015-01-01

    Xanthohumol may prevent and cure diabetes and atherosis, have oxidation resistance and antiviral function as well as anticancer effect preventing cancer cell metastasis. We investigate whether the anticancer effect of xanthohumol induces growth inhibition and apoptosis of human liver cancer through NF-κB/p53-apoptosis signaling pathway. Human liver cancer HepG2 cell were treated with 10, 20, 30 and 40 µM xanthohumol for 48 h. The present study showed that the anticancer effect of xanthohumol ...

  4. Prostaglandin E2 inhibits p53 in human breast adipose stromal cells: a novel mechanism for the regulation of aromatase in obesity and breast cancer.

    Science.gov (United States)

    Wang, Xuyi; Docanto, Maria M; Sasano, Hironobu; Lo, Camden; Simpson, Evan R; Brown, Kristy A

    2015-02-15

    Obesity is a risk factor for postmenopausal breast cancer and the majority of these cancers are estrogen dependent. Aromatase converts androgens into estrogens and its increased expression in breast adipose stromal cells (ASC) is a major driver of estrogen receptor-positive breast cancer. In particular, obesity-associated and tumor-derived factors, such as prostaglandin E2 (PGE2), have been shown to drive the expression of aromatase by stimulating the activity of the proximal promoter II (PII). The tumor-suppressor p53 is a key regulator of cell-cycle arrest and apoptosis and is frequently mutated in breast cancer. Mutations in p53 are rare in tumor-associated ASCs. Therefore, it was hypothesized that p53 is regulated by PGE2 and involved in the PGE2-mediated regulation of aromatase. Results demonstrate that PGE2 causes a significant decrease in p53 transcript and nuclear protein expression, as well as phosphorylation at Ser15 in primary human breast ASCs. Stabilization of p53 with RITA leads to a significant decrease in the PGE2-stimulated aromatase mRNA expression and activity, and PII activity. Interaction of p53 with PII was demonstrated and this interaction is decreased in the presence of PGE2. Moreover, mutation of the identified p53 response element leads to an increase in the basal activity of the promoter. Immunofluorescence on clinical samples demonstrates that p53 is decreased in tumor-associated ASCs compared with ASCs from normal breast tissue, and that there is a positive association between perinuclear (inactive) p53 and aromatase expression in these cells. Furthermore, aromatase expression is increased in breast ASCs from Li-Fraumeni patients (germline TP53 mutations) compared with non-Li-Fraumeni breast tissue. Overall, our results demonstrate that p53 is a negative regulator of aromatase in the breast and its inhibition by PGE2 provides a novel mechanism for aromatase regulation in obesity and breast cancer. ©2015 American Association for Cancer

  5. p53 protein aggregation promotes platinum resistance in ovarian cancer.

    Science.gov (United States)

    Yang-Hartwich, Y; Soteras, M G; Lin, Z P; Holmberg, J; Sumi, N; Craveiro, V; Liang, M; Romanoff, E; Bingham, J; Garofalo, F; Alvero, A; Mor, G

    2015-07-01

    High-grade serous ovarian carcinoma (HGSOC), the most lethal gynecological cancer, often leads to chemoresistant diseases. The p53 protein is a key transcriptional factor regulating cellular homeostasis. A majority of HGSOCs have inactive p53 because of genetic mutations. However, genetic mutation is not the only cause of p53 inactivation. The aggregation of p53 protein has been discovered in different types of cancers and may be responsible for impairing the normal transcriptional activation and pro-apoptotic functions of p53. We demonstrated that in a unique population of HGSOC cancer cells with cancer stem cell properties, p53 protein aggregation is associated with p53 inactivation and platinum resistance. When these cancer stem cells differentiated into their chemosensitive progeny, they lost tumor-initiating capacity and p53 aggregates. In addition to the association of p53 aggregation and chemoresistance in HGSOC cells, we further demonstrated that the overexpression of a p53-positive regulator, p14ARF, inhibited MDM2-mediated p53 degradation and led to the imbalance of p53 turnover that promoted the formation of p53 aggregates. With in vitro and in vivo models, we demonstrated that the inhibition of p14ARF could suppress p53 aggregation and sensitize cancer cells to platinum treatment. Moreover, by two-dimensional gel electrophoresis and mass spectrometry we discovered that the aggregated p53 may function uniquely by interacting with proteins that are critical for cancer cell survival and tumor progression. Our findings help us understand the poor chemoresponse of a subset of HGSOC patients and suggest p53 aggregation as a new marker for chemoresistance. Our findings also suggest that inhibiting p53 aggregation can reactivate p53 pro-apoptotic function. Therefore, p53 aggregation is a potential therapeutic target for reversing chemoresistance. This is paramount for improving ovarian cancer patients' responses to chemotherapy, and thus increasing their

  6. Anticancer effect of xanthohumol induces growth inhibition and apoptosis of human liver cancer through NF-κB/p53-apoptosis signaling pathway.

    Science.gov (United States)

    Zhao, Xiangqian; Jiang, Kai; Liang, Bin; Huang, Xiaoqiang

    2016-02-01

    Xanthohumol may prevent and cure diabetes and atherosis, have oxidation resistance and antiviral function as well as anticancer effect preventing cancer cell metastasis. We investigate whether the anticancer effect of xanthohumol induces growth inhibition and apoptosis of human liver cancer through NF-κB/p53-apoptosis signaling pathway. Human liver cancer HepG2 cell were treated with 10, 20, 30 and 40 µM xanthohumol for 48 h. The present study showed that the anticancer effect of xanthohumol was effective in inhibiting proliferation and inducing apoptosis of human liver cancer HepG2 cells. Furthermore, the caspase-3 activity of human liver cancer HepG2 cells was increased by xanthohumol. In addition, 48-h treatment with xanthohumol suppressed NF-κB expression and promoted p53, cleaved PARP, AIF and cytochrome c expression and downregulated XIAP and Bcl-2/Bax expression in human liver cancer HepG2 cells. Therefore, the anticancer effect of xanthohumol induces growth inhibition and apoptosis of human liver cancer through the NF-κB/p53-apoptosis signaling pathway.

  7. CQ synergistically sensitizes human colorectal cancer cells to SN-38/CPT-11 through lysosomal and mitochondrial apoptotic pathway via p53-ROS cross-talk.

    Science.gov (United States)

    Chen, Pinjia; Luo, Xiaoyong; Nie, Peipei; Wu, Baoyan; Xu, Wei; Shi, Xinpeng; Chang, Haocai; Li, Bing; Yu, Xiurong; Zou, Zhengzhi

    2017-03-01

    Autophagy plays a key role in supporting cell survival against chemotherapy-induced apoptosis. In this study, we found the chemotherapy agent SN-38 induced autophagy in colorectal cancer (CRC) cells. However, inhibition of autophagy using a small molecular inhibitor 3-methyladenine (3-MA) and ATG5 siRNA did not increase SN-38-induced cytotoxicity in CRC cells. Notably, another autophagy inhibitor chloroquine (CQ) synergistically enhanced the anti-tumor activity of SN-38 in CRC cells with wild type (WT) p53. Subsequently, we identified a potential mechanism of this cooperative interaction by showing that CQ and SN-38 acted together to trigger reactive oxygen species (ROS) burst, upregulate p53 expression, elicit the loss of lysosomal membrane potential (LMP) and mitochondrial membrane potential (∆ψm). In addition, ROS induced by CQ plus SN-38 upregulated p53 levels by activating p38, conversely, p53 stimulated ROS. These results suggested that ROS and p53 reciprocally promoted each other's production and cooperated to induce CRC cell death. Moreover, we showed induction of ROS and p53 by the two agents provoked the loss of LMP and ∆ψm. Altogether, all results suggested that CQ synergistically sensitized human CRC cells with WT p53 to SN-38 through lysosomal and mitochondrial apoptotic pathway via p53-ROS cross-talk. Lastly, we showed that CQ could enhance CRC cells response to CPT-11 (a prodrug of SN-38) in xenograft models. Thus the combined treatment might represent an attractive therapeutic strategy for the treatment of CRC.

  8. p53-dependent and p53-independent anticancer activity of a new indole derivative in human osteosarcoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Cappadone, C., E-mail: concettina.cappadone@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); Stefanelli, C. [Department for Life Quality Studies, University of Bologna, Rimini Campus, Rimini (Italy); Malucelli, E. [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); Zini, M. [Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna (Italy); Onofrillo, C. [Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna (Italy); Locatelli, A.; Rambaldi, M.; Sargenti, A. [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); Merolle, L. [ELETTRA–Sincrotrone Trieste S.C.p.A., Trieste (Italy); Farruggia, G. [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); National Institute of Biostructures and Biosystems, Roma (Italy); Graziadio, A. [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); Montanaro, L. [Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna (Italy); Iotti, S. [Department of Pharmacy and Biotechnology, University of Bologna, Bologna (Italy); National Institute of Biostructures and Biosystems, Roma (Italy)

    2015-11-13

    Osteosarcoma (OS) is the most common primary malignant tumor of bone, occurring most frequently in children and adolescents. The mechanism of formation and development of OS have been studied for a long time. Tumor suppressor pathway governed by p53 gene are known to be involved in the pathogenesis of osteosarcoma. Moreover, loss of wild-type p53 activity is thought to be a major predictor of failure to respond to chemotherapy in various human cancers. In previous studies, we described the activity of a new indole derivative, NSC743420, belonging to the tubulin inhibitors family, capable to induce apoptosis and arrest of the cell cycle in the G2/M phase of various cancer cell lines. However, this molecule has never been tested on OS cell line. Here we address the activity of NSC743420 by examine whether differences in the p53 status could influence its effects on cell proliferation and death of OS cells. In particular, we compared the effect of the tested molecule on p53-wild type and p53-silenced U2OS cells, and on SaOS2 cell line, which is null for p53. Our results demonstrated that NSC743420 reduces OS cell proliferation by p53-dependent and p53-independent mechanisms. In particular, the molecule induces proliferative arrest that culminate to apoptosis in SaOS2 p53-null cells, while it brings a cytostatic and differentiating effect in U2OS cells, characterized by the cell cycle arrest in G0/G1 phase and increased alkaline phosphatase activity. - Highlights: • The indole derivative NSC743420 induces antitumor effects on osteosarcoma cells. • p53 status could drive the activity of antitumor agents on osteosarcoma cells. • NSC743420 induces cytostatic and differentiating effects on U2OS cells. • NSC743420 causes apoptosis on p53-null SaOS2 cells.

  9. Targeted Knockdown of the Kinetochore Protein D40/Knl-1 Inhibits Human Cancer in a p53 Status-Independent Manner.

    Science.gov (United States)

    Urata, Yuri N; Takeshita, Fumitaka; Tanaka, Hiroki; Ochiya, Takahiro; Takimoto, Masato

    2015-09-08

    The D40 gene encodes a kinetochore protein that plays an essential role in kinetochore formation during mitosis. Short inhibitory RNA against D40, D40 siRNA, has been shown to deplete the D40 protein in the human cancer cell line HeLa, which harbors wild-type p53, and this activity was followed by the significant inhibition of cell growth and induction of apoptotic cell death. The p53-null cancer cell line, PC-3M-luc, is also sensitive to the significant growth inhibition and cell death induced by D40 siRNA. The growth of PC-3M-luc tumors transplanted into nude mice was inhibited by the systemic administration of D40 siRNA and the atelocollagen complex. Furthermore, D40 siRNA significantly inhibited growth and induced apoptotic cell death in a cell line with a gain-of-function (GOF) mutation in p53, MDA-MB231-luc, and also inhibited the growth of tumors transplanted into mice when administered as a D40 siRNA/atelocollagen complex. These results indicated that D40 siRNA induced apoptotic cell death in human cancer cell lines, and inhibited their growth in vitro and in vivo regardless of p53 status. Therefore, D40 siRNA is a potential candidate anti-cancer reagent.

  10. Identification of epigallocatechin-3-gallate in green tea polyphenols as a potent inducer of p53-dependent apoptosis in the human lung cancer cell line A549.

    Science.gov (United States)

    Yamauchi, Rieko; Sasaki, Kaori; Yoshida, Kenichi

    2009-08-01

    The effects of green tea polyphenols on cultured cancer cells have been well characterized, especially the effects of epigallocatechin-3-gallate (EGCg), since EGCg suppresses oncogenic signaling pathways and induces cell cycle arrest or apoptosis by regulating cell cycle-associated proteins. In the present study, we attempted to identify signaling pathways or target molecules regulated by each of or a mixture of green tea polyphenols, including epicatechin (EC), epicatechin-3-gallate (ECg), epigallocatechin (EGC), and EGCg, in the human lung cancer cell line A549. ECg, EGC, and a catechin mixture, in addition to EGCg, significantly decreased cell viability. In contrast, caspase 3/7 activity, an apoptosis indicator, was specifically induced by EGCg. By conducting a series of luciferase-based reporter assays, we revealed that the catechin mixture only up-regulates the p53 reporter. EGCg was a more potent inducer of p53-dependent transcription, and this induction was further supported by the induced level of p53 protein. RNA interference (RNAi)-mediated p53 knockdown completely abolished EGCg-induced apoptosis. Finally, a proteome and western blot analysis using approximately 70 different antibodies failed to detect up-regulated proteins in catechin mixture-treated A549 cells. Taken together, these results indicate that EGCg, among several green tea polyphenols, is a potent apoptosis inducer that functions exclusively through a p53-dependent pathway in A549 cells.

  11. p53 dependent apoptosis and cell cycle delay induced by heteroleptic complexes in human cervical cancer cells.

    Science.gov (United States)

    Sharma, Gunjan; Rana, Nishant Kumar; Singh, Priya; Dubey, Pradeep; Pandey, Daya Shankar; Koch, Biplob

    2017-04-01

    We previously reported synthesis of novel arene ruthenium (Ru) complexes and evaluated their antitumor activity in murine lymphoma (DL) cells. In this present study we further investigated the mechanism of action of two ruthenium complexes [complex 1 (η6-arene)RuCl(2-pcdpm)] and complex 2 (η6-arene)RuCl(4-mtdpm)] in cervical cancer cell line (HeLa). Our studies demonstrate that anticancer property of these two complexes was due to induction of apoptosis through p53 mediated pathway as well as arrest of cells in G2/M phase of cell cycle. It is worth to note that the complexes did not cause any substantial cytotoxic effect on normal cells. Further in comprehensive studies, apoptosis inducing property of both complexes were established in accordance with array of morphological changes ranging from membrane blebbing to formation of apoptotic bodies and followed by DNA fragmentation assay. Furthermore, Flow cytometry by Annexin V/PI staining delineate that complex 1 and 2 have strident impact to induce apoptosis in HeLa cells. The complex 1 and 2 treated cells show increased level of intracellular ROS generation which was preceded by p53 activation. Apoptosis induced by 1 and 2 was preceded by mitochondrial aggregations which were monitored by mitotracker. In addition flow cytometry analysis showed that both complexes also effectively arrest cells at G2/M phase of cell cycle. Western blot, RT-PCR as well as Real Time analysis were used to further confirm that the complexes induced apoptosis in p53 dependent pathway. Thus, our promising results can contribute to the rational design of novel potential anticancer agents. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Cell death by the quinoxaline dioxide DCQ in human colon cancer cells is enhanced under hypoxia and is independent of p53 and p21

    Directory of Open Access Journals (Sweden)

    Haddadin Makhluf J

    2010-11-01

    Full Text Available Abstract Introduction We have shown that the radio sensitizer DCQ enhances sensitivity of HCT116 human colon cancer cells to hypoxia. However, it is not known whether the p53 or p21 genes influence cellular response to DCQ. In this study, we used HCT116 that are either wildtype for p53 and p21, null for p53 or null for p21 to understand the role of these genes in DCQ toxicity. Methods HCT116 cells were exposed to DCQ and incubated under normoxia or hypoxia and the viability, colony forming ability, DNA damage and apoptotic responses of these cells was determined, in addition to the modulation of HIF-1α and of p53, p21, caspase-2, and of the ataxia telangiectasia mutated (ATM target PIDD-C. Results DCQ decreased colony forming ability and viability of all HCT116 cells to a greater extent under hypoxia than normoxia and the p21-/-cell line was most sensitive. Cells had different HIF-1α responses to hypoxia and/or drug treatment. In p53+/+, DCQ significantly inhibited the hypoxia-induced increases in HIF-1α protein, in contrast to the absence of a significant HIF-1α increase or modulation by DCQ in p21-/- cells. In p53-/- cells, 10 μM DCQ significantly reduced HIF-1α expression, especially under hypoxia, despite the constitutive expression of this protein in control cells. Higher DCQ doses induced PreG1-phase increase and apoptosis, however, lower doses caused mitotic catastrophe. In p53+/+ cells, apoptosis correlated with the increased expression of the pro-apoptotic caspase-2 and inhibition of the pro-survival protein PIDD-C. Exposure of p53+/+ cells to DCQ induced single strand breaks and triggered the activation of the nuclear kinase ATM by phosphorylation at Ser-1981 in all cell cycle phases. On the other hand, no drug toxicity to normal FHs74 Int human intestinal cell line was observed. Conclusions Collectively, our findings indicate that DCQ reduces the colony survival of HCT116 and induces apoptosis even in cells that are null for p53

  13. The anti-cancer activities of Vernonia amygdalina extract in human breast cancer cell lines are mediated through caspase-dependent and p53-independent pathways.

    Directory of Open Access Journals (Sweden)

    Fang Cheng Wong

    Full Text Available Breast cancer is currently the leading cause of cancer-related deaths among women globally. Notably, medicinal plant extracts may be a potential source for treatments of breast cancer. Vernonia amygdalina (VA is a woody shrub reported to have not only diverse therapeutic effects but also anti-cancer properties. However, current research about the mechanisms of the anti-cancer potential of VA has been limited. This study aimed to investigate the mechanisms of action of VA that underlie its anti-cancer effects in human breast cancer cell lines (MCF-7 and MDA-MB-231 cells. Results from MTT assay revealed that VA inhibits the proliferation of MCF-7 and MDA-MB-231, in a time- and dose-dependent manner. The underlying mechanism of this growth inhibition involved the stimulation of cell-type specific G1/S phase cell cycle arrest in only MCF-7 cells, and not in MDA-MB-231 cells. While the growth arrest was associated with increased levels of p53 and p21, and a concomitant decrease in the levels of cyclin D1 and cyclin E, it was shown that VA causes cell cycle arrest through a p53-independent pathway as tested by the wild type p53 inhibitor, pifithrin-α. Furthermore, this study revealed that VA induces apoptosis in the two cell lines, as indicated by the increase in Annexin V-positive cells and sub-G1 population, and that this VA-induced apoptosis occurred through both extrinsic and intrinsic apoptotic pathways. The apoptosis in MCF-7 cells was also likely to be caspase-dependent and not p53 transcriptional-dependent. Given that approximately 70% of diagnosed breast cancers express ER-α, a crucial finding was that VA inhibits the expression of ER-α and its downstream player, Akt, highlighting the potential clinical significance of VA. Moreover, VA exhibits synergism when combined with doxorubicin, suggesting that it can complement current chemotherapy. Overall, this study demonstrates the potential applications of VA as an anti-cancer drug for breast

  14. Protein degradation rate is the dominant mechanism accounting for the differences in protein abundance of basal p53 in a human breast and colorectal cancer cell line.

    Science.gov (United States)

    Lakatos, Eszter; Salehi-Reyhani, Ali; Barclay, Michael; Stumpf, Michael P H; Klug, David R

    2017-01-01

    We determine p53 protein abundances and cell to cell variation in two human cancer cell lines with single cell resolution, and show that the fractional width of the distributions is the same in both cases despite a large difference in average protein copy number. We developed a computational framework to identify dominant mechanisms controlling the variation of protein abundance in a simple model of gene expression from the summary statistics of single cell steady state protein expression distributions. Our results, based on single cell data analysed in a Bayesian framework, lends strong support to a model in which variation in the basal p53 protein abundance may be best explained by variations in the rate of p53 protein degradation. This is supported by measurements of the relative average levels of mRNA which are very similar despite large variation in the level of protein.

  15. Prosurvival long noncoding RNA PINCR regulates a subset of p53 targets in human colorectal cancer cells by binding to Matrin 3

    Science.gov (United States)

    Chaudhary, Ritu; Gryder, Berkley; Woods, Wendy S; Subramanian, Murugan; Jones, Matthew F; Li, Xiao Ling; Jenkins, Lisa M; Shabalina, Svetlana A; Mo, Min; Dasso, Mary; Yang, Yuan; Wakefield, Lalage M; Zhu, Yuelin; Frier, Susan M; Moriarity, Branden S; Prasanth, Kannanganattu V; Perez-Pinera, Pablo; Lal, Ashish

    2017-01-01

    Thousands of long noncoding RNAs (lncRNAs) have been discovered, yet the function of the vast majority remains unclear. Here, we show that a p53-regulated lncRNA which we named PINCR (p53-induced noncoding RNA), is induced ~100-fold after DNA damage and exerts a prosurvival function in human colorectal cancer cells (CRC) in vitro and tumor growth in vivo. Targeted deletion of PINCR in CRC cells significantly impaired G1 arrest and induced hypersensitivity to chemotherapeutic drugs. PINCR regulates the induction of a subset of p53 targets involved in G1 arrest and apoptosis, including BTG2, RRM2B and GPX1. Using a novel RNA pulldown approach that utilized endogenous S1-tagged PINCR, we show that PINCR associates with the enhancer region of these genes by binding to RNA-binding protein Matrin 3 that, in turn, associates with p53. Our findings uncover a critical prosurvival function of a p53/PINCR/Matrin 3 axis in response to DNA damage in CRC cells. DOI: http://dx.doi.org/10.7554/eLife.23244.001 PMID:28580901

  16. P53 MUTATIONS IN HUMAN LUNG-TUMORS

    NARCIS (Netherlands)

    MILLER, CW; ASLO, A; KOK, K; YOKOTA, J; BUYS, CHCM; TERADA, M; KOEFFLER, HP; Simon, K.

    1992-01-01

    Mutation of one p53 allele and loss of the normal p53 allele [loss of heterozygosity (LOH)] occur in many tumors including lung cancers. These alterations apparently contribute to development of cancer by interfering with the tumor suppressor activity of p53. We directly sequenced amplified DNA in t

  17. The novel anthraquinone derivative IMP1338 induces death of human cancer cells by p53-independent S and G2/M cell cycle arrest.

    Science.gov (United States)

    Choi, Hyun Kyung; Ryu, Hwani; Son, A-Rang; Seo, Bitna; Hwang, Sang-Gu; Song, Jie-Young; Ahn, Jiyeon

    2016-04-01

    To identify novel small molecules that induce selective cancer cell death, we screened a chemical library containing 1040 compounds in HT29 colon cancer and CCD18-Co normal colon cells, using a phenotypic cell-based viability assay system with the Cell Counting Kit-8 (CCK-8). We discovered a novel anthraquinone derivative, N-(4-[{(9,10-dioxo-9,10-dihydro-1-anthracenyl)sulfonyl}amino]phenyl)-N-methylacetamide (IMP1338), which was cytotoxic against the human colon cancer cells tested. The MTT cell viability assay showed that treatment with IMP1338 selectively inhibited HCT116, HCT116 p53(-/-), HT29, and A549 cancer cell proliferation compared to that of Beas2B normal epithelial cells. To elucidate the cellular mechanism underlying the cytotoxicity of IMP1338, we examined the effect of IMP1338 on the cell cycle distribution and death of cancer cells. IMP1338 treatment significantly arrested the cell cycle at S and G2/M phases by DNA damage and led to apoptotic cell death, which was determined using FACS analysis with Annexin V/PI double staining. Furthermore, IMP1338 increased caspase-3 cleavage in wild-type p53, p53 knockout HCT116, and HT29 cells as determined using immunoblotting. In addition, IMP1338 markedly induced the phosphorylation of histone H2AX and Chk1 in both cell lines while the combination of 5-fluorouracil (5-FU) and radiation inhibited the viability of HCT116, HCT116 p53(-/-), and HT29 cells compared to 5-FU or radiation alone. Our findings indicated that IMP1338 induced p53-independent cell death through S and G2/M phase arrest as well as DNA damage. These results provide a basis for future investigations assessing the promising anticancer properties of IMP1338.

  18. Mimulone-induced autophagy through p53-mediated AMPK/mTOR pathway increases caspase-mediated apoptotic cell death in A549 human lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Hyun-Kyu An

    Full Text Available Anticancer properties and mechanisms of mimulone (MML, C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3 puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA, pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy.

  19. Mimulone-Induced Autophagy through p53-Mediated AMPK/mTOR Pathway Increases Caspase-Mediated Apoptotic Cell Death in A549 Human Lung Cancer Cells

    Science.gov (United States)

    Lee, Ji-Won; Park, Mi-Hyun; Moon, Hyung-In; Park, Shin-Ji; Baik, Ji-Sue; Kim, Cheorl-Ho; Lee, Young-Choon

    2014-01-01

    Anticancer properties and mechanisms of mimulone (MML), C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3) puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC) staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA), pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ) suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α) and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy. PMID:25490748

  20. 人乳腺癌组织中p53基因单核苷酸多态性位点变异的研究%p53 gene mutation in human breast cancer tissues

    Institute of Scientific and Technical Information of China (English)

    王平; 任玮; 张玉和; 赵亮; 张玉宝

    2010-01-01

    目的 观察乳腺癌患者p53基因的单核苷酸多态性位点(SNPs)变异,探讨p53基因在乳腺癌癌基因学中的意义.方法 选取p53基因位于外显子及内含子的共3对引物,利用SSCP(单链多肽构象)分析方法对30例乳腺癌样品进行分析及DNA测序.结果 在检测的30例乳腺癌组织样品中,p53基因在第一内含子和第七内含子中共有4个碱基替换被检测出,其中3个为Hapmap(Hapolotype Map Project,国际单倍型图谱计划)中已公布的SNP位点,另外1个从未被确认.在p53第7内含子位置处发现一高突变率(20%)的G→A(rs12947788)类型基因替换,在其上游20个碱基位置处存在另一已知高突变率的SNP位点A→C(rs12951053),此两者联合出现,在所检测的30例乳腺癌组织样本中共发现6例,占所检测标本的20%.结论 p53基因的SNPs分析对乳腺癌的早期发现、治疗和预后有一定意义.%Objective To investigate the possible implication of the substitution at single Nucleotide Polymorphisms (SNPs) sites in p53 genes in the carcinogenesis of breast cancer. Methods The SNPs in p53 gene regions from 30 patients with breast cancer were analyzed by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and subsequent DNA sequencing. Results The totally 4 nucleotide substittution sites at the regions of intron 1 and intron 7 of p53 detected were found in 30 cases of breat cancer, which involved 3 published SNPs sites and 1 uncharacterized site. Among these substitutions, a G →A (rs12947788) mutation which occurred at the intron 7 was coupled with the cystidine nucleotide at a SNPs site A→C (rs12951053) of 20th nucleotide at its upstream, which occupied 20% of the breast cancer patients, implicaing the significance of the coupling of these two sites in the carcinogenesis of the breast cancer. Conclusion The DNA substitution analysis at the SNPs sites of p53 may serve as a helpful tool for the early diagnosis of breast

  1. A novel alkaloid, evodiamine causes nuclear localization of cytochrome-c and induces apoptosis independent of p53 in human lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Vijay [School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat (India); Agarwal, Rajesh [Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver, Aurora, CO (United States); Singh, Rana P., E-mail: ranaps@hotmail.com [School of Life Sciences, Central University of Gujarat, Gandhinagar, Gujarat (India); Cancer Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi (India)

    2016-09-02

    Lung cancer is the most frequently diagnosed malignancy that contributes to high proportion of deaths globally among patients who die due to cancer. Chemotherapy remains the common mode of treatment for lung cancer patients though with limited success. We assessed the biological effects and associated molecular changes of evodiamine, a plant alkaloid, on human lung cancer A549 and H1299 cells along with other epithelial cancer and normal lung SAEC cells. Our data showed that 20–40 μM evodiamine treatment for 24–48 h strongly (up to 73%, P < 0.001) reduced the growth and survival of these cancer cells. However, it also moderately inhibited growth and survival of SAEC cells. A strong inhibition (P < 0.001) was observed on clonogenicity of A549 cells. Further, evodiamine increased (4-fold) mitochondrial membrane depolarization with 6-fold increase in apoptosis and a slight increase in Bax/Bcl-2 ratio. It increased the cytochrome-c release from mitochondria into the cytosol as well as nucleus. Cytosolic cytochrome-c activated cascade of caspase-9 and caspase-3 intrinsic pathway, however, DR5 and caspase-8 extrinsic pathway was also activated which could be due to nuclear cytochrome-c. Pan-caspase inhibitor (z-VAD.fmk) partially reversed evodiamine induced apoptosis. An increase in p53 as well as its serine 15 phosphorylation was also observed. Pifithrin-α, a p53 inhibitor, slightly inhibited growth of A549 cells and under p53 inhibitory condition evodiamine-induced apoptosis could not be reversed. Together these findings suggest that evodiamine is a strong inducer of apoptosis in lung epithelial cancer cells independent of their p53 status and that could involve both intrinsic as well as extrinsic pathway of apoptosis. Thus evodiamine could be a potential anticancer agent against lung cancer. - Highlights: • Evodiamine, a novel plant alkaloid, relatively selectively inhibited growth and survival of human lung cancer cells. • Increased cancer cell

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

    NARCIS (Netherlands)

    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

  3. 转染 p53基因对肺腺癌细胞株裸鼠 移植瘤生长的影响%Study on the Role of p53 Gene Transfer on Human Glandular Lung Cancer Cell Growth in Nude Mice

    Institute of Scientific and Technical Information of China (English)

    李萍; 王北宁; 丁振若

    2001-01-01

    Objective: This study was designed to explore the significance and the role of wild-type p53 (wt-p53) gene and mutant p53 gene(mt-p53) transfer on human glandular lung cancer cell growth in nude mice. Methods: wt-p53 gene and mt-p53 gene were transfected and lipofectin-mediated into the human glandular lung cancer cell line GLC-82. And the growth of gene-transfected cell lines were observed in vitro and in vivo. Results: The colony number in the colong-forming experiment and the volume and weight in nude mice were greater in the mf-p53 tranfecting cells group than in the control group. The tumor resulting from the cells transfected with the wt-p53 gene grew more slowly and was smaller than that from control GLC-82 cells. In contrast, the tumor from the cells transfected with the mt-p53 gene grew faster than that produced by cells transfeted with the wt-p53 gene and that produced by control GLC-82 cells. Conclusion: The wild-type p53 gene could inhibit the glandular lung cancer cell growth in nude mice and the mutant p53 gene could enhance the glandular lung cancer cell growth in nude mice.%目的:探讨转染野生型 p53( wt-p53)和突变型 p53( mt-p53)基因对人肺腺癌细胞株 GLC-82裸鼠移植瘤生长的影响。方法:采用脂质体介导法,分别将 wt-p53和 mt-p53基因导入人肺腺癌细胞株 GLC-82,在裸鼠体内、体外实验中检测转导细胞的生长状况和裸鼠致瘤性。结果:转染 mt-p53 基因的细胞株 G418筛选的细胞集落数、 3H-TDR掺入实验、软琼脂平皿细胞集落数,以及裸鼠瘤组织重量和体积均高于对照组( P<0.01),而转染 wt p53基因的细胞株均显著低于对照组( P< 0.01),表明导入 wt p53基因的细胞株瘤细胞生长速度明显低于对照组细胞株和导入 mt p53基因的细胞株,即导入 mt p53基因的细胞株瘤细胞生长速度最快,而导入 wt p53基因的细胞株瘤细胞

  4. Illuminating p53 function in cancer with genetically engineered mouse models

    OpenAIRE

    2014-01-01

    The key role of the p53 protein in tumor suppression is highlighted by its frequent mutation in human cancers and by the completely penetrant cancer predisposition of p53 null mice. Beyond providing definitive evidence for the critical function of p53 in tumor suppression, genetically engineered mouse models have offered numerous additional insights into p53 function. p53 knock-in mice expressing tumor-derived p53 mutants have revealed that these mutants display gain-of-function activities th...

  5. Ligand dependent restoration of human TLR3 signaling and death in p53 mutant cells.

    Science.gov (United States)

    Menendez, Daniel; Lowe, Julie M; Snipe, Joyce; Resnick, Michael A

    2016-09-20

    Diversity within the p53 transcriptional network can arise from a matrix of changes that include target response element sequences and p53 expression level variations. We previously found that wild type p53 (WT p53) can regulate expression of most innate immune-related Toll-like-receptor genes (TLRs) in human cells, thereby affecting immune responses. Since many tumor-associated p53 mutants exhibit change-of-spectrum transactivation from various p53 targets, we examined the ability of twenty-five p53 mutants to activate endogenous expression of the TLR gene family in p53 null human cancer cell lines following transfection with p53 mutant expression vectors. While many mutants retained the ability to drive TLR expression at WT levels, others exhibited null, limited, or change-of-spectrum transactivation of TLR genes. Using TLR3 signaling as a model, we show that some cancer-associated p53 mutants amplify cytokine, chemokine and apoptotic responses after stimulation by the cognate ligand poly(I:C). Furthermore, restoration of WT p53 activity for loss-of-function p53 mutants by the p53 reactivating drug RITA restored p53 regulation of TLR3 gene expression and enhanced DNA damage-induced apoptosis via TLR3 signaling. Overall, our findings have many implications for understanding the impact of WT and mutant p53 in immunological responses and cancer therapy.

  6. Adenovirus-mediated p53 and ING4 gene co-transfer elicits synergistic antitumor effects through enhancement of p53 acetylation in breast cancer.

    Science.gov (United States)

    Wu, Jie; Zhu, Yanbo; Xu, Chun; Xu, Hong; Zhou, Xiumin; Yang, Jicheng; Xie, Yufeng; Tao, Min

    2016-01-01

    Multigene-based combination therapy may be an effective practice in cancer gene therapy. Substantial studies have demonstrated that tumor suppressor p53 acetylation is indispensable for p53 activation. Inhibitor of growth 4 (ING4), as a novel tumor suppressor, is capable of remarkably enhancing p53 acetylation and its transcriptional activity. Hence, we assumed that combined treatment of p53 and ING4 double tumor suppressors would exhibit enhanced antitumor effects. The combined therapeutic efficacy of p53 and ING4 for human cancers has not been previously reported. We thus generated multiple promoter expression cassette-based recombinant adenovirus-co-expressing ING4 and p53 double tumor suppressor genes (AdVING4/p53), evaluated the combined effects of AdVING4/p53 on breast cancer using the MDA-MB-231 (mutant p53) human breast cancer cell line, and also elucidated its underlying molecular mechanisms. We demonstrated that AdVING4/p53-mediated p53 and ING4 co-expression induced synergistic growth inhibition and apoptosis as well as enhanced effects on upregulation of acetylated p53, P21, Bax, PUMA, Noxa, cleaved caspase-9, cleaved caspase-3 and cleaved PARP, and downregulation of Bcl-2, CD31 and microvessel density (MVD) in MDA-MB-231 breast cancer in vitro and/or in vivo subcutaneous (s.c.) xenografted tumors. The synergistic antitumor activity elicited by AdVING4/p53 was closely associated with the enhanced activation of the intrinsic apoptotic pathway and synergistic inhibition of tumor angiogenesis, very possibly via ING4-mediated enhancement of p53 acetylation and activity. Thus, our results indicate that cancer gene therapy combining two or more tumor suppressors such as p53 and ING4 may constitute a novel and effective therapeutic modality for human breast cancer and other cancers.

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

    Directory of Open Access Journals (Sweden)

    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

  8. IκB kinase Mediating the Downregulation of p53 and p21 by Lipopolysaccharide in Human Papillomavirus 16+ Cervical Cancer Cells

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hui Tan; Yu Zhang; Yan Tian; Wei Tan; Ying-Hua Li

    2016-01-01

    Background:Cervical cancer is the second most common cancer of woman in the world,and human papillomavirus (HPV) infection plays an important role in the development of most of the cases.IκB kinase β (IKKβ) is a kinase-mediating nuclear factor kappa B (NF-κB) activation by phosphorylating the inhibitor ofNF-κB (IκB) and is related by some diseases caused by virus infection.However,there is little known about the correlation between IKKβ and HPV infection in cervical cancer.This study aimed to investigate the expression of IKKβ protein in cervical cancer tissues and effects of inflammation on HPV positive or negative cervical cancer cells through detecting the expression of IKKβ,IKBα,p53,and p21 proteins after treated with lipopolysaccharide (LPS) to mimic bacterial infection.We also examined the effects of LPS on cervical cancer cells after blocking IKKβ with pharmacological inhibitor.Methods:Thirty-six matched specimens of cervical cancer and adjacent normal tissues were collected and analyzed in the study.The expression of IKKβ in the tissue specimens was determined by immunohistochemical staining.In addition,Western blot was used to detect the expression level changes ofIKKβ,IκBα,p53,and p21 after LPS stimulated in the HPV16+ (SiHa) and HPV16-(C33A) cervical cancer cell lines.Furthermore,the effects of IKKβ inhibitor SC-514 on LPS-induced expression change of these proteins were investigated.Results:The expression of IKKβ was higher in cervical cancer than adjacent normal tissues,and there was no significant difference between tumor differentiation,size,and invasive depth with IKKβ expression.The LPS,which increased the expression level of IKKβ protein but decreased in the IκBα,p53 and p21 proteins,was illustrated in HPV16+ (SiHa) but not in HPV16-(C33A) cells.Moreover,IKKβ inhibitor SC-514 totally reversed the upregulation of IKKβ and downregulation of p53 and p21 by LPS in SiHa cells.Conclusions:IKKβ may mediate the downregulation of p

  9. Small-Molecule NSC59984 Restores p53 Pathway Signaling and Antitumor Effects against Colorectal Cancer via p73 Activation and Degradation of Mutant p53.

    Science.gov (United States)

    Zhang, Shengliang; Zhou, Lanlan; Hong, Bo; van den Heuvel, A Pieter J; Prabhu, Varun V; Warfel, Noel A; Kline, Christina Leah B; Dicker, David T; Kopelovich, Levy; El-Deiry, Wafik S

    2015-09-15

    The tumor-suppressor p53 prevents cancer development via initiating cell-cycle arrest, cell death, repair, or antiangiogenesis processes. Over 50% of human cancers harbor cancer-causing mutant p53. p53 mutations not only abrogate its tumor-suppressor function, but also endow mutant p53 with a gain of function (GOF), creating a proto-oncogene that contributes to tumorigenesis, tumor progression, and chemo- or radiotherapy resistance. Thus, targeting mutant p53 to restore a wild-type p53 signaling pathway provides an attractive strategy for cancer therapy. We demonstrate that small-molecule NSC59984 not only restores wild-type p53 signaling, but also depletes mutant p53 GOF. NSC59984 induces mutant p53 protein degradation via MDM2 and the ubiquitin-proteasome pathway. NSC59984 restores wild-type p53 signaling via p73 activation, specifically in mutant p53-expressing colorectal cancer cells. At therapeutic doses, NSC59984 induces p73-dependent cell death in cancer cells with minimal genotoxicity and without evident toxicity toward normal cells. NSC59984 synergizes with CPT11 to induce cell death in mutant p53-expressing colorectal cancer cells and inhibits mutant p53-associated colon tumor xenograft growth in a p73-dependent manner in vivo. We hypothesize that specific targeting of mutant p53 may be essential for anticancer strategies that involve the stimulation of p73 in order to efficiently restore tumor suppression. Taken together, our data identify NSC59984 as a promising lead compound for anticancer therapy that acts by targeting GOF-mutant p53 and stimulates p73 to restore the p53 pathway signaling.

  10. Benzyl Isothiocyanate potentiates p53 signaling and antitumor effects against breast cancer through activation of p53-LKB1 and p73-LKB1 axes

    Science.gov (United States)

    Xie, Bei; Nagalingam, Arumugam; Kuppusamy, Panjamurthy; Muniraj, Nethaji; Langford, Peter; Győrffy, Balázs; Saxena, Neeraj K.; Sharma, Dipali

    2017-01-01

    Functional reactivation of p53 pathway, although arduous, can potentially provide a broad-based strategy for cancer therapy owing to frequent p53 inactivation in human cancer. Using a phosphoprotein-screening array, we found that Benzyl Isothiocynate, (BITC) increases p53 phosphorylation in breast cancer cells and reveal an important role of ERK and PRAS40/MDM2 in BITC-mediated p53 activation. We show that BITC rescues and activates p53-signaling network and inhibits growth of p53-mutant cells. Mechanistically, BITC induces p73 expression in p53-mutant cells, disrupts the interaction of p73 and mutant-p53, thereby releasing p73 from sequestration and allowing it to be transcriptionally active. Furthermore, BITC-induced p53 and p73 axes converge on tumor-suppressor LKB1 which is transcriptionally upregulated by p53 and p73 in p53-wild-type and p53-mutant cells respectively; and in a feed-forward mechanism, LKB1 tethers with p53 and p73 to get recruited to p53-responsive promoters. Analyses of BITC-treated xenografts using LKB1-null cells corroborate in vitro mechanistic findings and establish LKB1 as the key node whereby BITC potentiates as well as rescues p53-pathway in p53-wild-type as well as p53-mutant cells. These data provide first in vitro and in vivo evidence of the integral role of previously unrecognized crosstalk between BITC, p53/LKB1 and p73/LKB1 axes in breast tumor growth-inhibition. PMID:28071670

  11. P53 tumor suppression network in cancer epigenetics.

    Science.gov (United States)

    Mishra, Alok; Brat, Daniel J; Verma, Mukesh

    2015-01-01

    The tumor suppressor p53 is one of the most complex and widely studied genes in cancer biology. In spite of the vast on literature the transcriptional regulation of p53, aspects of its especially epigenetic regulation are not completely understood. This chapter presents a concise overview of p53-related epigenetic events involved in oncogenesis and tumor suppression. We limit the scope to epigenetic modifications of the p53 promoter per se as well as its well-established downstream targets. The indirect role of p53 affecting the epigenetic machinery of cancer cells via specific proteins and transcription factors is discussed. Current concepts of p53-related cancer epigenetics offer myriad avenues for cancer therapies. Challenges in the field are also discussed.

  12. Characterization of human papillomavirus infection, P53 and Ki-67 expression in cervix cancer of Mozambican women.

    Science.gov (United States)

    Carrilho, Carla; Gouveia, Patricia; Cantel, Martha; Alberto, Matos; Buane, Landim; David, Leonor

    2003-01-01

    In this study, we aimed at evaluating the distribution of HPV types and the expression of P53 and Ki-67 in cervix carcinomas of Mozambican women. Fourty-seven invasive carcinomas, 10 CIN III, and 10 normal cervix were studied. P53 and Ki-67 expression was examined immunohistochemically. HPV infection and HPV types were detected by PCR (GP5+/bio-GP6+) and enzyme-immunoassay, respectively. Expression of P53 and Ki-67 and detection of HPV were as follows: normal cervix--0%, 10%, and 0%, respectively; CIN III--10%, 0%, and 100%, respectively; invasive carcinomas--50%, 55.5%, and 70%, respectively. HPV 16 was identified in 54% of invasive carcinomas, HPV 31, 33, 35, and 45 in 23%, "unidentified" HPV in 19%, and HPV 18 in 4% of invasive carcinomas. No significant associations were observed between P53 expression, Ki-67 expression, and HPV infection. In conclusion, we observed a high frequency of HPV infection in CIN III lesions and invasive carcinomas from Mozambican women, with HPV 16 representing the most frequent viral type. HPV status was not related to P53 and Ki-67 expression. Both P53 and Ki-67 are associated with invasive cervix carcinomas, mainly of the squamous keratinizing histotype.

  13. P53-mediated cell cycle arrest and apoptosis through a caspase-3-independent, but caspase-9-dependent pathway in oridonin-treated MCF-7 human breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Qiao CUI; Jing-hua YU; Jin-nan WU; Shin-ichi TASHIRO; Satoshi ONODERA; Mutsuhiko MINAMI; Takashi IKEJIMA

    2007-01-01

    Aim: To study the caspase-3-independent mechanisms in oridonin-induced MCF-7 human breast cancer cell apoptosis in vitro. Methods: The viability of oridonin-treated MCF-7 cells was measured by MTT (thiazole blue) assay. Apoptotic cells with condensed nuclei were visualized by phase contrast microscopy. Nucleoso-mal DNA fragmentation was assayed by agarose gel electrophoresis. The apoptotic ratio was determined by lactate dehydrogenase assay. Cell cycle alternation and mitochondrial membrane potential were measured by flow cytometric analysis. Bax, Bcl-2, caspase-3, caspase-9, heat shock protein (Hsp)90, p53, p-p53, p21, Poly (ADP-ribose) polymerase (PARP), and the inhibitor of caspase-activated Dnase (ICAD) protein expressions were detected by Western blot analysis. Results: Oridonin inhibited cell growth in a time- and dose-dependent manner. Cell cycle was altered through the upregulation of p53 and p21 protein expressions. Pan-caspase inhibitor Z-VAD-fmk and calpain inhibitor Ⅱ both decreased cell death ratio. Nucleosomal DNA fragmentation and the downregulation of △ψmit were detected in oridonin-induced MCF-7 cell apoptosis, which was involved in a postmitochondrial caspase-9-dependent pathway. Decreased Bcl-2 and Hsp90 expression levels and increased Bax and p21 expression levels were positively correlated with elevated levels of phosphorylated p53 phosphorylation. Moreover, PARP was partially cleaved by calpain rather than by capase-3. Conclusion: DNA damage provoked alternations in the mitochondrial and caspase-9 pathways as well as p53-mediated cell cycle arrest, but was not related to caspase-3 activity in oridonin-induced MCF-7 cells.

  14. Modulation of Janus kinase 2 by p53 in ovarian cancer cells.

    Science.gov (United States)

    Reid, Thomas; Jin, Xiaohong; Song, Hui; Tang, Huai-Jing; Reynolds, R Kevin; Lin, Jiayuh

    2004-08-20

    The constitutive activation of the Janus kinase 2 (JAK2) and mutation of the p53 tumor suppressor are both detected in human cancer. We examined the potential regulation of JAK2 phosphorylation by wild-type (wt) p53 in human ovarian cancer cell lines, Caov-3 and MDAH2774, which harbor mutant form of p53 tumor suppressor gene and high levels of phosphorylated JAK2. The wt p53 gene was re-introduced into the cells using an adenovirus vector. In addition to wt p53, mutant p53 22/23, mutant p53-175, and NCV (negative control virus) were introduced into the cells in the control groups. Expression of wt p53, but not that of p53-175 mutant, diminished JAK2 tyrosine phosphorylation in MDAH2774 and Caov-3 cell lines. Expression of wt p53 or p53 22/23 mutant did not cause a reduction in the phosphorylation of unrelated protein kinases, ERK1 and ERK2 (ERK1/2). The inhibition of JAK2 tyrosine phosphorylation can be reversed by tyrosine phosphatase inhibitor, sodium orthovanadate. Protein tyrosine phosphatase 1-B levels increased with introduction of wt p53 and may be involved in the dephosphorylation of JAK2. These findings present a possible p53-dependent cellular process of modulating JAK2 tyrosine phosphorylation in ovarian cancer cell lines.

  15. Combined treatment with vitamin C and sulindac synergistically induces p53- and ROS-dependent apoptosis in human colon cancer cells.

    Science.gov (United States)

    Gong, Eun-Yeung; Shin, Yu Jin; Hwang, Ih-Yeon; Kim, Jeong Hee; Kim, Seung-Mi; Moon, Jai-Hee; Shin, Jae-Sik; Lee, Dae-Hee; Hur, Dae Young; Jin, Dong-Hoon; Hong, Seung-Woo; Lee, Won Keun; Lee, Wang-Jae

    2016-09-06

    Sulindac has anti-neoplastic properties against colorectal cancers; however, its use as a chemopreventive agent has been limited due to toxicity and efficacy concerns. Combinatorial treatment of colorectal cancers has been attempted to maximize anti-cancer efficacy with minimal side effects by administrating NSAIDs in combination with other inhibitory compounds or drugs such as l-ascorbic acid (vitamin C), which is known to exhibit cytotoxicity towards various cancer cells at high concentrations. In this study, we evaluated a combinatorial strategy utilizing sulindac and vitamin C. The death of HCT116 cells upon combination therapy occurred via a p53-mediated mechanism. The combination therapeutic resistance developed in isogenic p53 null HCT116 cells and siRNA-mediated p53 knockdown HCT116 cells, but the exogenous expression of p53 in p53 null isogenic cells resulted in the induction of cell death. In addition, we investigated an increased level of intracellular ROS (reactive oxygen species), which was preceded by p53 activation. The expression level of PUMA (p53-upregulated modulator of apoptosis), but not Bim, was significantly increased in HCT116 cells in response to the combination treatment. Taken together, our results demonstrate that combination therapy with sulindac and vitamin C could be a novel anti-cancer therapeutic strategy for p53 wild type colon cancers.

  16. Identification of p53 and Its Isoforms in Human Breast Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Zorka Milićević

    2014-01-01

    Full Text Available In breast carcinoma, disruption of the p53 pathway is one of the most common genetic alterations. The observation that the p53 can express multiple protein isoforms adds a novel level of complexity to the outcome of p53 mutations. p53 expression was analysed by Western immunoblotting and immunohistochemistry using monoclonal antibodies DO-7, Pab240, and polyclonal antiserum CM-1. The more frequently p53-positive nuclear staining has been found in the invasive breast tumors. One of the most intriguing findings is that mutant p53 appears as discrete dot-shaped regions within the nucleus of breast cancer cells. In many malignant cells, the nucleolar sequestration of p53 is evident. These observations support the view that the nucleolus is involved directly in the mediation of p53 function or indirectly by the control of the localization of p53 interplayers. p53 expressed in the nuclear fraction of breast cancer cells revealed a wide spectrum of isoforms. p53 isoforms ΔNp53 (47 kDa and Δ133p53β (35 kDa, known as dominant-negative repressors of p53 function, were detected as the most predominant variants in nuclei of invasive breast carcinoma cells. The isoforms expressed also varied between individual tumors, indicating potential roles of these p53 variants in human breast cancer.

  17. FAT10 level in human gastric cancer and its relation with mutant p53 level, lymph node metastasis and TNM staging

    Institute of Scientific and Technical Information of China (English)

    Feng Ji; Xi Jin; Chun-Hua Jiao; Qin-Wei Xu; Zi-Wei Wang; Yue-Liang Chen

    2009-01-01

    AIM: To investigate the role of FAT10 and mutant p53 in the pathogenesis, severity and prognosis of gastric cancer. METHODS: FAT10, mutant p53 mRNA and protein levels were measured by reverse transcription (RT)-PCR and immunohistochemistry in gastric cancer tissue ( n = 62), tumor-adjacent tissue ( n = 62) and normal gastric tissue ( n = 62). Relation of FAT10 and mutant p53 expression with clinicopathological features and clinical outcomes of gastric cancer patients were analyzed. RESULTS: The FAT10, mutant p53 mRNA and protein levels were significantly higher in gastric cancer than in its adjacent and normal tissue. The FAT10 and mutant p53 levels in gastric cancer tissue were significantly correlated with lymph node metastasis and tumor, nodes, metastasis (TNM) staging. Moreover, the high FAT10 level was associated with the overall survival rate of patients. Multivariate Cox-proportional hazards model analysis showed that mRNA and protein levels of FAT10 and mutant p53, lymph node metastasis, distant metastasis and TNM stage were the independent prognostic factors for gastric cancer. CONCLUSION: FAT10 may be involved in gastric carcinogenesis, and is a potential marker for the prognosis of gastric cancer patients. FAT10 and mutant p53 may play a common role in the carcinogenesis of gastric cancer.

  18. Mutant p53 accumulation in human breast cancer is not an intrinsic property or dependent on structural or functional disruption but is regulated by exogenous stress and receptor status.

    Science.gov (United States)

    Bouchalova, Pavla; Nenutil, Rudolf; Muller, Petr; Hrstka, Roman; Appleyard, M Virginia; Murray, Karen; Jordan, Lee B; Purdie, Colin A; Quinlan, Philip; Thompson, Alastair M; Vojtesek, Borivoj; Coates, Philip J

    2014-07-01

    Many human cancers contain missense TP53 mutations that result in p53 protein accumulation. Although generally considered as a single class of mutations that abrogate wild-type function, individual TP53 mutations may have specific properties and prognostic effects. Tumours that contain missense TP53 mutations show variable p53 stabilization patterns, which may reflect the specific mutation and/or aspects of tumour biology. We used immunohistochemistry on cell lines and human breast cancers with known TP53 missense mutations and assessed the effects of each mutation with four structure-function prediction methods. Cell lines with missense TP53 mutations show variable percentages of cells with p53 stabilization under normal growth conditions, ranging from approximately 50% to almost 100%. Stabilization is not related to structural or functional disruption, but agents that stabilize wild-type p53 increase the percentages of cells showing missense mutant p53 accumulation in cell lines with heterogeneous stabilization. The same heterogeneity of p53 stabilization occurs in primary breast cancers, independent of the effect of the mutation on structural properties or functional disruption. Heterogeneous accumulation is more common in steroid receptor-positive or HER2-positive breast cancers and cell lines than in triple-negative samples. Immunohistochemcal staining patterns associate with Mdm2 levels, proliferation, grade and overall survival, whilst the type of mutation reflects downstream target activity. Inhibiting Mdm2 activity increases the extent of p53 stabilization in some, but not all, breast cancer cell lines. The data indicate that missense mutant p53 stabilization is a complex and variable process in human breast cancers that associates with disease characteristics but is unrelated to structural or functional properties. That agents which stabilize wild-type p53 also stabilize mutant p53 has implications for patients with heterogeneous mutant p53 accumulation

  19. Constitutively activated ERK sensitizes cancer cells to doxorubicin: Involvement of p53-EGFR-ERK pathway

    Indian Academy of Sciences (India)

    RATNA KUMARI; SURBHI CHOUHAN; SNAHLATA SINGH; RISHI RAJ CHHIPA; AMRENDRA KUMAR AJAY; MANOJ KUMAR BHAT

    2017-03-01

    The tumour suppressor gene p53 is mutated in approximately 50% of the human cancers. p53 is involved in genotoxicstress-induced cellular responses. The role of EGFR and ERK in DNA-damage-induced apoptosis is well known. Weinvestigated the involvement of activation of ERK signalling as a consequence of non-functional p53, in sensitivity ofcells to doxorubicin. We performed cell survival assays in cancer cell lines with varying p53 status: MCF-7 (wild-typep53, WTp53), MDA MB-468 (mutant p53, MUTp53), H1299 (absence of p53, NULLp53) and an isogenic cell lineMCF-7As (WTp53 abrogated). Our results indicate that enhanced chemosensitivity of cells lacking wild-type p53function is because of elevated levels of EGFR which activates ERK. Additionally, we noted that independent of p53status, pERK contributes to doxorubicin-induced cell death.

  20. Translational regulation of human p53 gene expression.

    OpenAIRE

    Fu, L.; Minden, M D; Benchimol, S

    1996-01-01

    In blast cells obtained from patients with acute myelogenous leukemia, p53 mRNA was present in all the samples examined while the expression of p53 protein was variable from patient to patient. Mutations in the p53 gene are infrequent in this disease and, hence, variable protein expression in the majority of the samples cannot be accounted for by mutation. In this study, we examined the regulation of p53 gene expression in human leukemic blasts and characterized the p53 transcripts in these c...

  1. Quercetin induces p53-independent apoptosis in human prostate cancer cells by modulating Bcl-2-related proteins: a possible mediation by IGFBP-3.

    Science.gov (United States)

    Vijayababu, Marati R; Kanagaraj, P; Arunkumar, A; Ilangovan, R; Dharmarajan, A; Arunakaran, J

    2006-01-01

    Quercetin, a flavonoid found in onion, grapes, green vegetables, etc., has been shown to possess potent antiproliferative effects against various malignant cells. We report insulin-like growth factor-binding protein-3 (IGFBP-3) as an effector of quercetin-induced apoptosis in human prostate cancer cell lines in a p53-independent manner. We evaluated the production of IGFBP-3 in quercetin-treated cells. Apoptosis was studied in quercetin-treated cells to study the IGFBP-3-mediated role with flow cytometry and DNA fragmentation. Protein expressions of Bcl-2, Bcl-x(L), and Bax were studied by Western blot. Increased production of IGFBP-3 was associated with the increased ratio of proapoptotic to antiapoptotic members of the Bcl-2 family. In quercetin-treated PC-3 cells, an increase in Bax protein expression and a decrease in Bcl-x(L) protein and Bcl-2 protein were observed. As PC-3 is a p53-negative cell line, these modulations of proapoptotic proteins and induction of apoptosis were independent of p53. The level of IGFBP-3 on the response of PC-3 cells to quercetin was examined. There was a twofold increase in IGFBP-3 level in conditioned media of 100 microM quercetin-treated cells. Quercetin also brought a peak at sub-G1 in PC-3 cells. Thus, increased level of IGFBP-3 was associated with increased proapoptotic proteins and apoptosis in response to quercetin, suggesting it may be a p53-independent effector of apoptosis in prostate cancer cells via its modulation of the Bax/Bcl-2 protein ratio.

  2. Human papillomavirus and p53 expression in cancer of unknown primary in the head and neck region in relation to clinical outcome.

    Science.gov (United States)

    Sivars, Lars; Näsman, Anders; Tertipis, Nikolaos; Vlastos, Andrea; Ramqvist, Torbjörn; Dalianis, Tina; Munck-Wikland, Eva; Nordemar, Sushma

    2014-04-01

    Patients with cancer of unknown primary (CUP) in the head neck region are generally treated with neck dissection followed by radiotherapy at times combined with chemotherapy, a treatment associated with considerable side effects. Some of these tumors may originate as human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OSCC), with better clinical outcome than head neck squamous cell cancer (HNSCC) in general, and could potentially do well with less treatment. Here, we therefore investigated whether HPV status and p53-expression correlated to clinical outcome in patients with CUP in the head neck region. Fifty metastases were analyzed for presence of HPV DNA, and expression of p16(INK4A) and p53 and the data were correlated to clinical outcome. Patients with HPV DNA-positive (HPVDNA+) metastases had significantly better 5-year overall survival (OS) compared to those with HPVDNA- metastases (80.0% vs. 36.7%, respectively; P = 0.004), with a similar tendency for disease-free survival (DFS). These survival rates showed excellent concordance with those of HPVDNA+ and HPVDNA- OSCC in Sweden during the same time period, strengthening the hypothesis that HPVDNA+ head and neck CUP may originate from HPVDNA+ OSCC. In addition, having absent/intermediary-low as compared to high expression of p53 correlated to a better prognosis with a 69% as compared to 14% 5-year OS, respectively (P p53 expression are valuable prognostic factors in patients with CUP in the head and neck region and should be further explored for clinical use.

  3. Nuclear inclusion bodies of mutant and wild-type p53 in cancer: a hallmark of p53 inactivation and proteostasis remodeling by p53 aggregation.

    Science.gov (United States)

    De Smet, Frederik; Saiz Rubio, Mirian; Hompes, Daphne; Naus, Evelyne; De Baets, Greet; Langenberg, Tobias; Hipp, Mark S; Houben, Bert; Claes, Filip; Charbonneau, Sarah; Blanco, Javier Delgado; Plaisance, Stephane; Ramkissoon, Shakti; Ramkissoon, Lori; Simons, Colinda; van den Brandt, Piet; Weijenberg, Matty; Van England, Manon; Lambrechts, Sandrina; Amant, Frederic; D'Hoore, André; Ligon, Keith L; Sagaert, Xavier; Schymkowitz, Joost; Rousseau, Frederic

    2016-12-30

    Although p53 protein aggregates have been observed in cancer cell lines and tumour tissue, their impact in cancer remains largely unknown. Here, we extensively screened for p53 aggregation phenotypes in tumour biopsies and identified nuclear inclusion bodies (nIBs) of transcriptionally inactive mutant or wild-type p53 as the most frequent aggregation-like phenotype across six different cancer types. p53-positive nIBs co-stained with nuclear aggregation markers and shared molecular hallmarks of nIBs commonly found in neurodegenerative disorders. In cell culture, tumour-associated stress was a strong inducer of p53 aggregation and nuclear inclusion body formation. This was most prominent for mutant p53, but could also be observed in wild-type p53 cell lines for which nIB formation correlated to the loss of p53s transcriptional activity. Importantly, protein aggregation also fueled the dysregulation of the proteostasis network in the tumour cell by inducing a hyper-activated, oncogenic heat-shock response to which tumours are commonly addicted, and by overloading the proteasomal degradation system, an observation that was most pronounced for structurally destabilized mutant p53. Patients exhibiting tumours with p53-positive nIBs suffered from a poor clinical outcome similar to loss-of-p53-expression, and tumour biopsies displayed a differential proteostatic expression profile associated to p53-nIBs. p53-positive nIBs therefore highlight a malignant state of the tumour that results from the interplay between (i) the functional inactivation of p53 through mutation and/or aggregation and (ii) microenvironmental stress, a combination that catalyses proteostatic dysregulation. This study highlights several unexpected clinical, biological and therapeutically unexplored parallels between cancer and neurodegeneration.

  4. Evidence for selection against human lung cancers bearing p53 missense mutations which occur within the HLA A*0201 peptide consensus motif.

    Science.gov (United States)

    Wiedenfeld, E A; Fernandez-Viña, M; Berzofsky, J A; Carbone, D P

    1994-03-01

    Short peptide fragments of intracellular proteins that fit a defined sequence motif bind to the most common human major histocompatibility complex class I molecule, HLA A*0201, and mediate killing by cytotoxic T-cells [D.F. Hunt et al., Science (Washington DC), 255: 1261-1263, 1992; K. Falk et al., Nature (Lond.), 351: 290-296, 1991]. The existence of such a motif allows prediction of whether novel peptides derived from mutant oncoporteins might be presented on the surface of cancer cells bearing that HLA allele. Clinical cancer might develop only when these mutations occur outside a major histocompatibility complex binding motif or in those cells that acquire defects in antigen presentation. Here, we find that missense mutations of p53 from a variety of tumors fall within the HLA A*0201 motif less often than would be expected if the location of mutations and motifs were independent. When we analyzed the HLA subtype of lung cancer cell lines with known p53 missense mutations, we found that all of the mutant oncopeptides predicted to be presentable by HLA A*0201 came from tumors that either did not carry the A*0201 allele or had lost that allele in the process of tumorigenesis. Presentation of mutant oncogene peptides on class I major histocompatibility complex might thus represent a physiologically significant selection pressure in the development of human cancer.

  5. Modulation of cell death in human colorectal and breast cancer cells through a manganese chelate by involving GSH with intracellular p53 status.

    Science.gov (United States)

    Banerjee, Kaushik; Das, Satyajit; Majumder, Saikat; Majumdar, Subrata; Biswas, Jaydip; Choudhuri, Soumitra Kumar

    2017-03-01

    Chemotherapy is central to current treatment modality especially for advanced and metastatic colorectal and breast cancers. Targeting the key molecular events of the neoplastic cells may open a possibility to treat cancer. Although some improvements in understanding of colorectal and breast cancer treatment have been recorded, the involvement of glutathione (GSH) and dependency of p53 status on the modulation of GSH-mediated treatment efficacy have been largely overlooked. Herein, we tried to decipher the underlying mechanism of the action of Mn-N-(2-hydroxyacetophenone) glycinate (MnNG) against differential p53 status bearing Hct116, MCF-7, and MDA-MB-468 cells on the backdrop of intracellular GSH level and reveal the role of p53 status in modulating GSH-dependant abrogation of MnNG-induced apoptosis in these cancer cells. Present study discloses that MnNG targets specifically wild-type-p53 expressing Hct116 and MCF-7 cells by significantly depleting both cytosolic, mitochondrial GSH, and modulating nuclear GSH through Glutathione reductase and Glutamate-cysteine ligase depletion that may in turn induce p53-mediated intrinsic apoptosis in them. Thus GSH addition abrogates p53-mediated apoptosis in wild-type-p53 expressing cells. GSH addition also overrides MnNG-induced modulation of phase II detoxifying parameters in them. However, GSH addition partially replenishes the down-regulated or modulated GSH pool in cytosol, mitochondria, and nucleus, and relatively abrogates MnNG-induced intrinsic apoptosis in p53-mutated MDA-MB-468 cells. On the contrary, although MnNG induces significant cell death in p53-null Hct116 cells, GSH addition fails to negate MnNG-induced cell death. Thus p53 status with intracellular GSH is critical for the modulation of MnNG-induced apoptosis.

  6. Adenovirus-based p53 gene therapy in ovarian cancer.

    Science.gov (United States)

    Santoso, J T; Tang, D C; Lane, S B; Hung, J; Reed, D J; Muller, C Y; Carbone, D P; Lucci, J A; Miller, D S; Mathis, J M

    1995-11-01

    Mutations of the p53 tumor suppressor gene are the most common molecular genetic abnormality to be described in ovarian cancer. To determine the feasibility of mutant p53 as a molecular target for gene therapy in ovarian cancer, we constructed an adenovirus vector containing the wild-type p53 gene. The ability of this adenovirus construct (Ad-CMV-p53) to express p53 protein was examined by Western blot analysis in the H358 lung cancer cell line, which has a homozygous deletion of the p53 gene. The ability of the adenovirus vector system to infect ovarian cancer cells was tested using an adenovirus containing the beta-galactosidase reporter gene under the control of the CMV promoter (Ad-CMV-beta gal). The ovarian cancer cell line 2774, which contains an Arg273His p53 mutation, was infected with Ad-CMV-beta gal, and the infected cells were assayed for beta-galactosidase activity after 24 hr. To test the ability of wild-type p53 to inhibit cell growth, the 2774 cell line was infected with Ad-CMV-p53 or Ad-CMV-beta gal, and the effect of these agents on the growth of 2774 cells was determined using an in vitro growth inhibition assay. Western blot analysis of lysates from H358 cells infected with Ad-CMV-p53 showed expression of wild-type p53 protein. When 2774 cells were infected with Ad-CMV-beta gal at a multiplicity of infection (m.o.i.) of 10 PFU/cell, > 90% of cells showed beta-galactosidase activity, demonstrating that these cells are capable of efficient infection by the adenovirus vector. Growth of 2774 cells infected with Ad-CMV-p53 was inhibited by > 90% compared to noninfected cells. The ability of the adenovirus vector to mediate high-level expression of infected genes and the inhibitory effect of Ad-CMV-p53 on the 2774 cell line suggests that the Ad-CMV-p53 could be further developed into a therapeutic agent for ovarian cancer.

  7. Reactivating mutant p53 using small molecules as zinc metallochaperones: awakening a sleeping giant in cancer.

    Science.gov (United States)

    Blanden, Adam R; Yu, Xin; Loh, Stewart N; Levine, Arnold J; Carpizo, Darren R

    2015-11-01

    Tumor protein p53 (TP53) is the most commonly mutated gene in human cancer. The majority of mutations are missense, and generate a defective protein that is druggable. Yet, for decades, the small-molecule restoration of wild-type (WT) p53 function in mutant p53 tumors (so-called p53 mutant 'reactivation') has been elusive to researchers. The p53 protein requires the binding of a single zinc ion for proper folding, and impairing zinc binding is a major mechanism for loss of function in missense mutant p53. Here, we describe recent work defining a new class of drugs termed zinc metallochaperones that restore WT p53 structure and function by restoring Zn(2+) to Zn(2+)-deficient mutant p53.

  8. Effects of Selenium Dioxide on Apoptosis, Bcl-2 and P53 Expression, Intracellular Reactive Oxygen Species and Calcium Level in Three Human Lung Cancer Cell Lines

    Institute of Scientific and Technical Information of China (English)

    WEIYaming; YUHaijian; ZHAOXiyan; BAIHai

    2004-01-01

    To evaluate the anti-tumor effects of SeO2 and its mechanisms on three human lung cancer cell lines. Methods: Three lung cancer cells A549, GLC-82 and PG were treated with 3-30 μmol/L SeO2. Flow cytometry was used to detect apoptosis, and analyze the changes of expression of p53 and Bcl-2, as well as ROS and Ca2+ level within cells. Results:SeO2 markedly inhibited cell proliferation and viability, and prompted apoptosis after 48 h treatment. SeO2 at 10 μmol/L induced 47.8% apoptosis in A549 cells, 40.8% in GLC-82 cells, 18.2% in PG cells. SeO2 at 30 μmol/L induced 37.8% apoposis in PG cells,but did not increase apoptotic raes in other two cells. SeO2 could down-regulate the mean fluorescent intensity of Bcl-2 from 65.8 to 9.6 in A549, but not in GLC-82 and in PG, cells, up-regulate wild type p53 level in all three cells. SeO2 decreased the ROS and Ca2+ level markedly within three tested cells. Conclusion: SeO2 showed anti-tumor effect via apoptosis pathway in three lung cancer cell lines. The decrease of ROS and Ca2+ level within cells as well as regulation of Bcl-2 and p53 expression may play important roles in above apoptotic procedure.

  9. The effect of adenovirus expressing wild-type p53 on 5-fiuorouracil chemosensitivity is related to p53 status in pancreatic cancer cell lines

    Institute of Scientific and Technical Information of China (English)

    Sven Eisold; Michael Linnebacher; Eduard Ryschich; Dalibor Antolovic; Ulf Hinz; Ernst Klar; Jan Schmidt

    2004-01-01

    AIM: There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU).Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status.METHODS: Human pancreatic cancer cell lines Capan-1p53mut,Capan-2p53wt, FAMPACp53mut, PANC1p53mut, and rat pancreatic cancer cell lines ASp53wt and DSL6Ap53null were used for in vitro studies. Following infection with different ratios of Adp53-particles (MOI) in combination with 5-FU, proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining). In addition, DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivo studies.Tumor size, apoptosis (TUNEL) and survival were determined.RESULTS: Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53. In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU. Both in vitro and in vivo analyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU.CONCLUSION: Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function. These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.

  10. The importance of p53 pathway genetics in inherited and somatic cancer genomes.

    Science.gov (United States)

    Stracquadanio, Giovanni; Wang, Xuting; Wallace, Marsha D; Grawenda, Anna M; Zhang, Ping; Hewitt, Juliet; Zeron-Medina, Jorge; Castro-Giner, Francesc; Tomlinson, Ian P; Goding, Colin R; Cygan, Kamil J; Fairbrother, William G; Thomas, Laurent F; Sætrom, Pål; Gemignani, Federica; Landi, Stefano; Schuster-Böckler, Benjamin; Bell, Douglas A; Bond, Gareth L

    2016-04-01

    Decades of research have shown that mutations in the p53 stress response pathway affect the incidence of diverse cancers more than mutations in other pathways. However, most evidence is limited to somatic mutations and rare inherited mutations. Using newly abundant genomic data, we demonstrate that commonly inherited genetic variants in the p53 pathway also affect the incidence of a broad range of cancers more than variants in other pathways. The cancer-associated single nucleotide polymorphisms (SNPs) of the p53 pathway have strikingly similar genetic characteristics to well-studied p53 pathway cancer-causing somatic mutations. Our results enable insights into p53-mediated tumour suppression in humans and into p53 pathway-based cancer surveillance and treatment strategies.

  11. Downregulation of wild-type p53 protein by HER-2/neu mediated PI3K pathway activation in human breast cancer cells:its effect on cell proliferation and implication for therapy

    Institute of Scientific and Technical Information of China (English)

    Li ZHENG; Jia Qiang REN; Hua LI; Zhao Lu KONG; Hong Guang ZHU

    2004-01-01

    Overexpression and activation of HER-2/neu (also known as c-erbB-2), a proto-oncogene, was found in about 30%of human breast cancers, promoting cancer growth and making cancer cells resistant to chemo- and radio-therapy.Wild-type p53 is crucial in regulating cell growth and apoptosis and is found to be mutated or deleted in 60-70% of human cancers. And some cancers with a wild-type p53 do not have normal p53 function, suggesting that it is implicated in a complex process regulated by many factors. In the present study, we showed that the overexpression of HER-2/neu could decrease the amount of wild-type p53 protein via activating PI3K pathway, as well as inducing MDM2 nuclear translocation in MCF7 human breast cancer ceils. Blockage of PI3K pathway with its specific inhibitor LY294002 caused G1-S phase arrest, decreased cell growth rate and increased chemo- and radio-therapeutic sensitivity in MCF7 cells expressing wild-type p53. However, it did not increase the sensitivity to adriamycin in MDA-MB-453 breast cancer cells containing mutant p53. Our study indicates that blocking PI3K pathway activation mediated by HER-2/neu overexpression may be useful in the treatment of breast tumors with HER-2/neu overexpression and wild-type p53.

  12. Cochinchina momordica seed extract induces apoptosis and cell cycle arrest in human gastric cancer cells via PARP and p53 signal pathways.

    Science.gov (United States)

    Liu, Hong-Rui; Meng, Lin-Yi; Lin, Zhi-Yan; Shen, Yang; Yu, Yun-Qiu; Zhu, Yi-Zhun

    2012-01-01

    Cochinchina momordica seed is the dried ripe seed of Momordica cochinchinensis (Lour.) Spreng, which is a kind of fruit and consumed for dietary as well as medicinal uses. In this study, using the human SGC7901 and MKN-28 gastric cancer cell lines, we explored the anticancer activity of the extract from cochinchina momordica seed (ECMS). ECMS inhibited significantly the survival rates of SGC7901 and MKN-28 cells in concentration- and time-dependent manners by MTT assay. The typical apoptotic morphological changes were observed by Hoechst 33258 dye assay after SGC7901 and MKN-28 cells were treated with ECMS for 48 h. Flow cytometry analysis revealed that ECMS-treatment blocked the cells at the S phase of cell cycle. Furthermore, the protein expression levels of poly (ADP-ribose) polymerase (PARP) and Bcl-2 were downregulated notably by ECMS-treatment, whereas those of Fas/Fas-associated death domain, p53, and Bax were upregulated in SGC7901 cells. ECMS dramatically enhanced the enzymatic activities of caspase-3 and caspase-9 whilst slightly increased caspase-8 activity. Taken together, this study demonstrated that ECMS exerted cytotoxic activities via PARP and p53 signal pathways in the human gastric cancer cells.

  13. Low-dose irradiation promotes proliferation of the human breast cancer MDA-MB-231 cells through accumulation of mutant P53.

    Science.gov (United States)

    Li, Si-Jie; Liang, Xin-Yue; Li, Hai-Jun; Li, Wei; Zhou, Lei; Chen, Hua-Qiu; Ye, Song-Gen; Yu, De-Hai; Cui, Jiu-Wei

    2017-01-01

    Low-dose irradiation (LDIR) has been proven to have differential biological effects on normal mammalian somatic cells and cancer cells. Our previous study showed that p53 gene status is a critical factor regulating the effect of LDIR on cancer cells. We investigated the effect of LDIR on the breast cancer cell line MDA-MB-231 that harbors a mutant p53 gene, and the normal breast fibroblast cell line Hs 578Bst. In the present study, we showed that 150 mGy LDIR pormoted growth of MDA-MB-231 cells but not Hs 578Bst cells. Through cell cycle analyses, we found that LDIR accelerated cell cycle into S phase in MDA-MB-231 cells, but did not affect the cell cycle of Hs 578Bst cells. Using western blotting, we demonstrated that the expression of CDK4, CDK6 and cyclin D1 was upregulated in MDA-MB-231 cells after LDIR. Although LDIR increased ataxia-telangiectasia mutated (ATM) level in both MDA-MB-231 cells and Hs 578Bst cells and activated ATM/p53/p21 pathway, only the mutant type of p53 (mtp53) protein in MDA-MB-231 cells was shown to be accumulated after LDIR. Using ATM inhibitor or lentivirus-mediated small interfering RNA (siRNA) to block the ATM/p53/p21 pathway in MDA-MB-231 cells, the LDIR-induced cell proliferation was abolished. When we introduced wild-type p53 (wtp53) protein into MDA-MB-231 cells, the LDIR-induced cell proliferation was also abolished. These findings suggest that normal p53 function is crucial in ATM/p53/p21 pathway activated by LDIR. The p53 status is the most probable reason leading to differential LDIR biological activities between breast tumor cells and normal breast cells.

  14. Anticancer Effects of a New SIRT Inhibitor, MHY2256, against Human Breast Cancer MCF-7 Cells via Regulation of MDM2-p53 Binding.

    Science.gov (United States)

    Park, Eun Young; Woo, Youngwoo; Kim, Seong Jin; Kim, Do Hyun; Lee, Eui Kyung; De, Umasankar; Kim, Kyeong Seok; Lee, Jaewon; Jung, Jee H; Ha, Ki-Tae; Choi, Wahn Soo; Kim, In Su; Lee, Byung Mu; Yoon, Sungpil; Moon, Hyung Ryong; Kim, Hyung Sik

    2016-01-01

    The sirtuins (SIRTs), a family of NAD(+)-dependent class III histone deacetylase, are involved in various biological processes including cell survival, division, senescence, and metabolism via activation of the stress-response pathway. Recently, inhibition of SIRTs has been considered a promising anticancer strategy, but their precise mechanisms of action are not well understood. In particular, the relevance of p53 to SIRT-induced effects has not been fully elucidated. We investigated the anticancer effects of a novel SIRT inhibitor, MHY2256, and its efficacy was compared to that of salermide in MCF-7 (wild-type p53) and SKOV-3 (null-type p53) cells. Cell viability, SIRT1 enzyme activity, cell cycle regulation, apoptosis, and autophagic cell death were measured. We compared sensitivity to cytotoxicity in MCF-7 and SKOV-3 cells. MHY2256 significantly decreased the viability of MCF-7 (IC50, 4.8 μM) and SKOV-3 (IC50, 5.6 μM) cells after a 48 h treatment period. MHY2256 showed potent inhibition (IC50, 0.27 mM) against SIRT1 enzyme activity compared with nicotinamide (IC50, >1 mM). Moreover, expression of SIRT (1, 2, or 3) protein levels was significantly reduced by MHY2256 treatment in both MCF-7 and SKOV-3 cells. Flow cytometry analysis revealed that MHY2256 significantly induced cell cycle arrest in the G1 phase, leading to an effective increase in apoptotic cell death in MCF-7 and SKOV-3 cells. A significant increase in acetylated p53, a target protein of SIRT, was observed in MCF-7 cells after MHY2256 treatment. MHY2256 up-regulated LC3-II and induced autophagic cell death in MCF-7 cells. Furthermore, MHY2256 markedly inhibited tumor growth in a tumor xenograft model of MCF-7 cells. These results suggest that a new SIRT inhibitor, MHY2256, has anticancer activity through p53 acetylation in MCF-7 human breast cancer cells.

  15. Wildtype p53-specific antibody and T-cell responses in cancer patients

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Stryhn, Anette; Justesen, Sune

    2011-01-01

    Mutation in the p53 gene based on single amino acid substitutions is a frequent event in human cancer. Accumulated mutant p53 protein is released to antigen presenting cells of the immune system and anti-p53 immune responses even against wt p53 is induced and observed in a number of human cancer...... patients. Detection of antibodies against wt p53 protein has been used as a diagnostic and prognostic marker and discovery of new T-cell epitopes has enabled design of cancer vaccination protocols with promising results. Here, we identified wt p53-specific antibodies in various cancer patients......(264-272) in breast cancer patients and against HLA-A*01:01 binding peptide wt p53(226-234) and HLA-B*07:02 binding peptide wt p53(74-82) in renal cell cancer and breast cancer patients, respectively. Finally, we analyzed antibody and T-cell responses against wt p53 15-mer peptides in patients with metastatic renal...

  16. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Sridhar

    2010-05-01

    Full Text Available Abstract Background Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene, a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. Methods We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Results Resveratrol (100-150 μM exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. Conclusions For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and

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

    NARCIS (Netherlands)

    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,

  18. NF-rBp50、p53、Bcl-2在宫颈癌组织中的表达及其与人乳头瘤病毒感染的关系%Expressions of NF-κBp50, p53 and Bcl-2 in cervical cancer and their relationship with human papillomavirus infection*

    Institute of Scientific and Technical Information of China (English)

    张婵; 陈向敏; 夏克栋

    2006-01-01

    Objective: To explore the relationship between expressions of NF-κBp50, p53 and Bcl-2 in tissue of cervical cancer and human papillomavirus (HPV) infection. Methods: The expressions of NF-κBp50, p53 and Bcl-2 were detected using immuohistochemical staining in 46 specimens of cervical cancer and 26 specimens of normal cervical tissue. The infection of HPV DNA were determined by PCR. Results: The expressions of NF-κBp50, p53 and Bcl-2 in tissue of cervical cancer were significantly higher than that in normal cervical tissue (P<0.01), and the expressions of NF-κBp50 and p53 or Bcl-2 were closely related (P<0.05). The expression of NF-κBp50 in HPV DNA positive group was significantly higher than that in HPV negative group (P<0.05), but there were no significantly differences in the expressions of p53 and Bcl-2 between HPV DNA positive group and HPV negative group (P>0.05). Conclusion: The expressions of NF-κBp50, p53 and Bcl-2 were significantly correlated with cervical carcinogenesis. NF-κBp50 may be activated by HPV infection.

  19. p53 mediates the suppression of cancer cell invasion by inducing LIMA1/EPLIN.

    Science.gov (United States)

    Ohashi, Tomoko; Idogawa, Masashi; Sasaki, Yasushi; Tokino, Takashi

    2017-04-01

    The tumor suppressor gene p53 is frequently mutated in human cancer. p53 executes various functions, such as apoptosis induction and cell cycle arrest, by modulating transcriptional regulation. In this study, LIM domain and Actin-binding protein 1 (LIMA1) was identified as a target of the p53 family using a cDNA microarray. We also evaluated genome-wide occupancy of the p53 protein by performing chromatin immunoprecipitation-sequencing (ChIP-seq) and identified two p53 response elements in the LIMA1 gene. LIMA1 protein levels were increased by treatment with nutlin-3a, a small molecule that activates endogenous p53. In addition, LIMA1 expression was significantly downregulated in cancers compared with normal tissues. Knockdown of LIMA1 significantly enhanced cancer cell invasion and partially inhibited p53-induced suppression of cell invasion. Furthermore, low expression of LIMA1 in cancer patients correlated with decreased survival and poor prognosis. Thus, p53-induced LIMA1 inhibits cell invasion, and the downregulation of LIMA1 caused by p53 mutation results in decreased survival in cancer patients. Collectively, this study reveals the molecular mechanism of LIMA1 downregulation in various cancers and suggests that LIMA1 may be a novel prognostic predictor and a therapeutic target for cancer.

  20. Epicatechin gallate induces cell death via p53 activation and stimulation of p38 and JNK in human colon cancer SW480 cells.

    Science.gov (United States)

    Cordero-Herrera, Isabel; Martín, María Angeles; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2013-01-01

    The tea flavonoid epicatechin gallate (ECG) exhibits a wide range of biological activities. In this study, the in vitro anticancer effects of ECG on SW480 colon cancer cell line was investigated by analyzing the cell cycle, apoptosis, key proteins involved in cellular survival/proliferation, namely AKT/phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinases (MAPKs), and the role of p53 in these processes. ECG induced cell cycle arrest at the G0/G1-S phase border associated with the stimulation of p21, p-p53, and p53 and the suppression of cyclins D1 and B1. Exposure of SW480 cells to ECG also led to apoptosis as determined by time-dependent changes in caspase-3 activity, MAPKs [extracellular regulated kinase (ERK), p38, and c-jun amino-terminal kinase (JNK)], p21 and p53 activation, and AKT inhibition. The presence of pifithrin, an inhibitor of p53 function, blocked ECG-induced apoptosis as was manifested by restored cell viability and caspase-3 activity to control values and reestablished the balance among Bcl-2 anti- and proapoptotic protein levels. Interestingly, ECG also inhibited p53 protein and RNA degradation, contributing to the stabilization of p53. In addition, JNK and p38 have been identified as necessary for ECG-induced apoptosis, upon activation by p53. The results suggest that the activation of the p53-p38/JNK cascade is required for ECG-induced cell death in SW480 cells.

  1. Molecular Mechanisms of p53 Deregulation in Cancer: An Overview in Multiple Myeloma.

    Science.gov (United States)

    Herrero, Ana B; Rojas, Elizabeta A; Misiewicz-Krzeminska, Irena; Krzeminski, Patryk; Gutiérrez, Norma C

    2016-11-30

    The p53 pathway is inactivated in the majority of human cancers. Although this perturbation frequently occurs through the mutation or deletion of p53 itself, there are other mechanisms that can attenuate the pathway and contribute to tumorigenesis. For example, overexpression of important p53 negative regulators, such as murine double minute 2 (MDM2) or murine double minute 4 (MDM4), epigenetic deregulation, or even alterations in TP53 mRNA splicing. In this work, we will review the different mechanisms of p53 pathway inhibition in cancer with special focus on multiple myeloma (MM), the second most common hematological malignancy, with low incidence of p53 mutations/deletions but growing evidence of indirect p53 pathway deregulation. Translational implications for MM and cancer prognosis and treatment are also reviewed.

  2. Uncovering the role of p53 splice variants in human malignancy: a clinical perspective

    Directory of Open Access Journals (Sweden)

    Surget S

    2013-12-01

    Full Text Available Sylvanie Surget,1,2 Marie P Khoury,1,2 Jean-Christophe Bourdon1,21Dundee Cancer Centre, 2Jacqui Wood Cancer Centre, Ninewells Hospital, University of Dundee, Dundee, UKAbstract: Thirty-five years of research on p53 gave rise to more than 68,000 articles and reviews, but did not allow the uncovering of all the mysteries that this major tumor suppressor holds. How p53 handles the different signals to decide the appropriate cell fate in response to a stress and its implication in tumorigenesis and cancer progression remains unclear. Nevertheless, the uncovering of p53 isoforms has opened new perspectives in the cancer research field. Indeed, the human TP53 gene encodes not only one but at least twelve p53 protein isoforms, which are produced in normal tissues through alternative initiation of translation, usage of alternative promoters, and alternative splicing. In recent years, it became obvious that the different p53 isoforms play an important role in regulating cell fate in response to different stresses in normal cells by differentially regulating gene expression. In cancer cells, abnormal expression of p53 isoforms contributes actively to cancer formation and progression, regardless of TP53 mutation status. They can also be associated with response to treatment, depending on the cell context. The determination of p53 isoform expression and p53 mutation status helps to define different subtypes within a particular cancer type, which would have different responses to treatment. Thus, the understanding of the regulation of p53 isoform expression and their biological activities in relation to the cellular context would constitute an important step toward the improvement of the diagnostic, prognostic, and predictive values of p53 in cancer treatment. This review aims to summarize the involvement of p53 isoforms in cancer and to highlight novel potential therapeutic targets.Keywords: p53, isoforms, p63, p73, alternative splicing, cancer

  3. Aspirin acetylates wild type and mutant p53 in colon cancer cells: identification of aspirin acetylated sites on recombinant p53.

    Science.gov (United States)

    Ai, Guoqiang; Dachineni, Rakesh; Kumar, D Ramesh; Marimuthu, Srinivasan; Alfonso, Lloyd F; Bhat, G Jayarama

    2016-05-01

    Aspirin's ability to inhibit cell proliferation and induce apoptosis in cancer cell lines is considered to be an important mechanism for its anti-cancer effects. We previously demonstrated that aspirin acetylated the tumor suppressor protein p53 at lysine 382 in MDA-MB-231 human breast cancer cells. Here, we extended these observations to human colon cancer cells, HCT 116 harboring wild type p53, and HT-29 containing mutant p53. We demonstrate that aspirin induced acetylation of p53 in both cell lines in a concentration-dependent manner. Aspirin-acetylated p53 was localized to the nucleus. In both cell lines, aspirin induced p21(CIP1). Aspirin also acetylated recombinant p53 (rp53) in vitro suggesting that it occurs through a non-enzymatic chemical reaction. Mass spectrometry analysis and immunoblotting identified 10 acetylated lysines on rp53, and molecular modeling showed that all lysines targeted by aspirin are surface exposed. Five of these lysines are localized to the DNA-binding domain, four to the nuclear localization signal domain, and one to the C-terminal regulatory domain. Our results suggest that aspirin's anti-cancer effect may involve acetylation and activation of wild type and mutant p53 and induction of target gene expression. This is the first report attempting to characterize p53 acetylation sites targeted by aspirin.

  4. p53 gene mutations in human esophageal cancer and human esophageal tissues treated with AMN%p53基因在人食管诱发癌中的突变

    Institute of Scientific and Technical Information of China (English)

    李利亚; 唐劲天; 刘轩; 贾倞; 周东辉; 李佩文

    2004-01-01

    目的:了解抑癌基因p53在人食管癌及其癌旁组织中的突变和致癌作用.方法:采用PCR-SSCP和DNA序列分析等方法对24例人食管鳞状细胞癌术后标本和21例移植到重度完全性免疫缺陷(severe combined immunodeficient,SCID)小鼠并用或不用N-戊基-N-甲基亚硝基胺(N-amyl-N-methylnitrosamine,AMN)处理的人食管正常组织标本,进行了p53基因外显子4~8的突变研究分析.结果:在食管癌组织及癌旁组织均检测出p53基因突变,其中食管癌组织标本中有18个突变,癌旁组织标本中有10个(10/17,58.8%)突变,主要的突变为G -A转换.在14例用AMN处理的人食管正常组织标本中出现6个(42.9%)突变;其中密码子283的突变为G-A转换.在人食管癌及其癌旁组织中p53基因的突变概率差异无统计学意义.结论:环境因素或内源性AMN可能是河南林县食管癌高发的主要原因之一.

  5. MicroRNA-34a induces a senescence-like change via the down-regulation of SIRT1 and up-regulation of p53 protein in human esophageal squamous cancer cells with a wild-type p53 gene background.

    Science.gov (United States)

    Ye, Zhimin; Fang, Jun; Dai, Shujun; Wang, Yuezhen; Fu, Zhenfu; Feng, Wei; Wei, Qichun; Huang, Pintong

    2016-01-28

    MiR-34a has been reported as a non-coding RNA universally expressed in normal old cells and a probable suppressor of diverse cancer cells; however, this miRNA's expression and anti-tumor mechanism in esophageal squamous cancer cells (ESCC) remains unclear. We explored these questions in three human ESCC lines, KYSE-450, KYSE-410, and ECa-109, with wild-type p53 and mutant p53 backgrounds. Through a specific stem-loop RT primer for miR-34a, we examined the relevant expression level of miR-34a in these three cell lines using real-time reverse transcription PCR (qRT-PCR). We found that the expression level of miR-34a induced by the DNA damage agent adrmycin (ADR) was both p53- and time-dependent. Following incubation with miR-34a, cellular growth inhibition was exhibited differently in the three cell lines harbored with different p53 backgrounds. Furthermore, the MTT assay demonstrated an miR-34a-related cytotoxic effect in cell growth. Senescence-associated β-galactosidase (SA-β-Gal) staining was used to examine senescence-like phenotypes induced by miR-34a. Mechanistic investigation suggested that the down-regulation of Sirtuin1 (SIRT1) and up-regulation of p53/p21 contributed to the anti-tumor mechanism of miR-34a in wild-type p53 ECa-109 cells, while neither of the apoptosis-related proteins PARP and caspase-3 caused significant changes. In summary, our findings indicated that the intrinsic expression of miR-34a was relatively low and was expressed differently among different p53 backgrounds and ADR treatment times. The anti-tumor effect of miR-34a was primarily dependent on the regulation of SIRT1 and p53/p21 protein, not apoptosis-associated proteins.

  6. p53 and survival in early onset breast cancer

    DEFF Research Database (Denmark)

    Gentile, M; Bergman Jungeström, M; Olsen, K E;

    1999-01-01

    The p53 protein has proven to be central in tumorigenesis by its cell cycle regulatory properties and both gene mutations and protein accumulation have been associated with poor prognosis in breast cancer. The present study was undertaken to investigate the prognostic significance of gene mutations......, p53 protein accumulation and of loss of heterozygosity (LOH) at the TP53 locus in young (age breast cancer patients. In total, gene mutations were found in 21 of the 123 patients (17%), LOH in 20 of the 47 informative cases (43%) and protein accumulation in 47 of the 102 available cases...... in this as well as other studies, p53 protein accumulation is frequently found in young breast cancer patients, but this protein overexpression appears to be of minor significance for survival. Nevertheless, the present report also suggests that specific mutations contribute substantially to tumour aggressiveness....

  7. Modeling the Etiology of p53-mutated Cancer Cells.

    Science.gov (United States)

    Perez, Ricardo E; Shen, Hong; Duan, Lei; Kim, Reuben H; Kim, Terresa; Park, No-Hee; Maki, Carl G

    2016-05-06

    p53 gene mutations are among the most common alterations in cancer. In most cases, missense mutations in one TP53 allele are followed by loss-of-heterozygosity (LOH), so tumors express only mutant p53. TP53 mutations and LOH have been linked, in many cases, with poor therapy response and worse outcome. Despite this, remarkably little is known about how TP53 point mutations are acquired, how LOH occurs, or the cells involved. Nutlin-3a occupies the p53-binding site in MDM2 and blocks p53-MDM2 interaction, resulting in the stabilization and activation of p53 and subsequent growth arrest or apoptosis. We leveraged the powerful growth inhibitory activity of Nutlin-3a to select p53-mutated cells and examined how TP53 mutations arise and how the remaining wild-type allele is lost or inactivated. Mismatch repair (MMR)-deficient colorectal cancer cells formed heterozygote (p53 wild-type/mutant) colonies when cultured in low doses of Nutlin-3a, whereas MMR-corrected counterparts did not. Placing these heterozygotes in higher Nutlin-3a doses selected clones in which the remaining wild-type TP53 was silenced. Our data suggest silencing occurred through a novel mechanism that does not involve DNA methylation, histone methylation, or histone deacetylation. These data indicate MMR deficiency in colorectal cancer can give rise to initiating TP53 mutations and that TP53 silencing occurs via a copy-neutral mechanism. Moreover, the data highlight the use of MDM2 antagonists as tools to study mechanisms of TP53 mutation acquisition and wild-type allele loss or silencing in cells with defined genetic backgrounds.

  8. The role of p53 and pRB in apoptosis and cancer

    DEFF Research Database (Denmark)

    Hickman, Emma S; Moroni, M Cristina; Helin, Kristian

    2002-01-01

    Loss of function of both the p53 pathway and the retinoblastoma protein (pRB) pathway plays a significant role in the development of most human cancers. Loss of pRB results in deregulated cell proliferation and apoptosis, whereas loss of p53 desensitizes cells to checkpoint signals, including...

  9. The expanding regulatory universe of p53 in gastrointestinal cancer.

    Science.gov (United States)

    Fesler, Andrew; Zhang, Ning; Ju, Jingfang

    2016-01-01

    Tumor suppresser gene TP53 is one of the most frequently deleted or mutated genes in gastrointestinal cancers. As a transcription factor, p53 regulates a number of important protein coding genes to control cell cycle, cell death, DNA damage/repair, stemness, differentiation and other key cellular functions. In addition, p53 is also able to activate the expression of a number of small non-coding microRNAs (miRNAs) through direct binding to the promoter region of these miRNAs.  Many miRNAs have been identified to be potential tumor suppressors by regulating key effecter target mRNAs. Our understanding of the regulatory network of p53 has recently expanded to include long non-coding RNAs (lncRNAs). Like miRNA, lncRNAs have been found to play important roles in cancer biology.  With our increased understanding of the important functions of these non-coding RNAs and their relationship with p53, we are gaining exciting new insights into the biology and function of cells in response to various growth environment changes. In this review we summarize the current understanding of the ever expanding involvement of non-coding RNAs in the p53 regulatory network and its implications for our understanding of gastrointestinal cancer.

  10. Autophagy induced by p53-reactivating molecules protects pancreatic cancer cells from apoptosis.

    Science.gov (United States)

    Fiorini, Claudia; Menegazzi, Marta; Padroni, Chiara; Dando, Ilaria; Dalla Pozza, Elisa; Gregorelli, Alex; Costanzo, Chiara; Palmieri, Marta; Donadelli, Massimo

    2013-03-01

    TP53 mutations compromising p53 transcriptional function occur in more than 50 % of human cancers, including pancreatic adenocarcinoma, and render cancer cells more resistant to conventional therapy. In the last few years, many efforts have been addressed to identify p53-reactivating molecules able to restore the wild-type transcriptionally competent conformation of the mutated proteins. Here, we show that two of these compounds, CP-31398 and RITA, induce cell growth inhibition, apoptosis, and autophagy by activating p53/DNA binding and p53 phosphorylation (Ser15), without affecting the total p53 amount. These effects occur in both wild-type and mutant p53 pancreatic adenocarcinoma cell lines, whereas they are much less pronounced in normal human primary fibroblasts. Furthermore, CP-31398 and RITA regulate the axis SESN1-2/AMPK/mTOR by inducing AMPK phosphorylation on Thr172, which has a crucial role in the autophagic response. The protective role of autophagy in cell growth inhibition by CP-31398 and RITA is supported by the finding that the AMPK inhibitor compound C or the autophagy inhibitors chloroquine or 3-methyladenine sensitize both pancreatic adenocarcinoma cell lines to the apoptotic response induced by p53-reactivating molecules. Our results demonstrate for the first time a survival role for autophagy induced by p53-reactivating molecules, supporting the development of an anti-cancer therapy based on autophagy inhibition associated to p53 activation.

  11. Expression of P53 and C -myc Protein in Human Testicular Cancer%P53、C-myc蛋白在睾丸肿瘤中的表达及意义

    Institute of Scientific and Technical Information of China (English)

    吴先旺; 董青

    2005-01-01

    目的:探讨P53、C-myc蛋白在睾丸肿瘤中的表达及其临床价值.方法:应用免疫组化技术法检测47例睾丸肿瘤P53、C-myc蛋白阳性表达水平.结果:发现P53、C-myc蛋白表达阳性率分别为44.7%(21/47)和51.1%(24/47),其阳性率与肿瘤临床分期呈显著正相关(P<0.05),P53蛋白阳性表达与C-myc蛋白阳性表达呈高度正相关(P<0.05).结论:联合检测P53、C-myc蛋白有助于判断睾丸肿瘤的恶性程度及患者的预后.

  12. Role of the lncRNA-p53 regulatory network in cancer.

    Science.gov (United States)

    Zhang, Ali; Xu, Min; Mo, Yin-Yuan

    2014-06-01

    Advances in functional genomics have led to discovery of a large group of previous uncharacterized long non-coding RNAs (lncRNAs). Emerging evidence indicates that lncRNAs may serve as master gene regulators through various mechanisms. Dysregulation of lncRNAs is often associated with a variety of human diseases including cancer. Of significant interest, recent studies suggest that lncRNAs participate in the p53 tumor suppressor regulatory network. In this review, we discuss how lncRNAs serve as p53 regulators or p53 effectors. Further characterization of these p53-associated lncRNAs in cancer will provide a better understanding of lncRNA-mediated gene regulation in the p53 pathway. As a result, lncRNAs may prove to be valuable biomarkers for cancer diagnosis or potential targets for cancer therapy.

  13. PHF2 histone demethylase acts as a tumor suppressor in association with p53 in cancer.

    Science.gov (United States)

    Lee, K-H; Park, J-W; Sung, H-S; Choi, Y-J; Kim, W H; Lee, H S; Chung, H-J; Shin, H-W; Cho, C-H; Kim, T-Y; Li, S-H; Youn, H-D; Kim, S J; Chun, Y-S

    2015-05-28

    Plant homeodomain finger 2 (PHF2) has a role in epigenetic regulation of gene expression by demethylating H3K9-Me2. Several genome-wide studies have demonstrated that the chromosomal region including the PHF2 gene is often deleted in some cancers including colorectal cancer, and this finding encouraged us to investigate the tumor suppressive role of PHF2. As p53 is a critical tumor suppressor in colon cancer, we tested the possibility that PHF2 is an epigenetic regulator of p53. PHF2 was associated with p53, and thereby, promoted p53-driven gene expression in cancer cells under genotoxic stress. PHF2 converted the chromatin that is favorable for transcription by demethylating the repressive H3K9-Me2 mark. In an HCT116 xenograft model, PHF2 was found to be required for the anticancer effects of oxaliplatin and doxorubicin. In PHF2-deficient xenografts, p53 expression was profoundly induced by both drugs, but its downstream product p21 was not, suggesting that p53 cannot be activated in the absence of PHF2. To find clinical evidence about the role of PHF2, we analyzed the expressions of PHF2, p53 and p21 in human colon cancer tissues and adjacent normal tissues from patients. PHF2 was downregulated in cancer tissues and PHF2 correlated with p21 in cancers expressing functional p53. Colon and stomach cancer tissue arrays showed a positive correlation between PHF2 and p21 expressions. Informatics analyses using the Oncomine database also supported our notion that PHF2 is downregulated in colon and stomach cancers. On the basis of these findings, we propose that PHF2 acts as a tumor suppressor in association with p53 in cancer development and ensures p53-mediated cell death in response to chemotherapy.

  14. Alterations in tumour suppressor gene p53 in human gliomas from Indian patients

    Indian Academy of Sciences (India)

    Pornima Phatak; S Kalai Selvi; T Divya; A S Hegde; Sridevi Hegde; Kumaravel Somasundaram

    2002-12-01

    Alterations in the tumour suppressor p53 gene are among the most common defects seen in a variety of human cancers. In order to study the significance of the p53 gene in the genesis and development of human glioma from Indian patients, we checked 44 untreated primary gliomas for mutations in exons 5–9 of the p53 gene by PCR-SSCP and DNA sequencing. Sequencing analysis revealed six missense mutations. The incidence of p53 mutations was 13.6% (6 of 44). All the six mutations were found to be located in the central core domain of p53, which carries the sequence-specific DNA-binding domain. These results suggest a rather low incidence but a definite involvement of p53 mutations in the gliomas of Indian patients.

  15. Platinum-(Ⅳ)-derivative satraplatin induced G2/M cell cycle perturbation via p53-p21waf1/cip1-independent pathway in human colorectal cancer cells

    Institute of Scientific and Technical Information of China (English)

    Murugan KALIMUTHO; Antonella MINUTOLO; Sandro GRELLI; Giorgio FEDERICI; Sergio BERNARDINI

    2011-01-01

    Aim:Platinum-(Ⅳ)-derivative satraplatin represents a new generation of orally available anti-cancer drugs that are under development for the treatment of several cancers.Understanding the mechanisms of cell cycle modulation and apoptosis is necessary to define the mode of action of satraplatin.In this study,we investigate the ability of satraplatin to induce cell cycle perturbation,clonogenicity loss and apoptosis in colorectal cancer (CRC) cells.Methods:CRC cells were treated with satraplatin,and the effects of satraplatin on apoptosis and the cell cycle were evaluated by flow cytometry.Western blot analysis was used to investigate the effects of satraplatin on cell cycle and apoptosis-related proteins.RTqPCR was used to evaluate p53-related mRNA modulation.Results:Satraplatin induced an accumulation of CRC cells predominantly in the G2/M phase.Increased p53 protein expression was observed in the p53 wild-type HCT116 and LoVo cells together with p21waf1/cip1 protein up-regulation.However,p21waf1/cip1 protein accumulation was not observed in the p53 mutant HCT15,HT29,and WiDr cells,even when p53 protein expression was compromised,suggesting that the cell cycle perturbation is p53-p21waf1/cip1 independent.Following a candidate approach,we found an elevated expression of 14-3-3o protein levels in CRC cells,which was independent of the status of p53,further supporting the role of satraplatin in the perturbation of the G2/M cell cycle phase.Moreover,satraplatin treatment induced apoptosis along with Bcl-2 protein down-regulation and abrogated the clonogenic formation of CRC cells in vitro.Conclusion:Collectively,our data suggest that satraplatin induces apoptosis in CRC cells,which is preceded by cell cycle arrest at G2/M due to the effect of 14-3-3σ and in a p53-p21waf1/cip1-independent manner.Taken together,these findings highlight the potential use of satraplatin for CRC treatment.

  16. Convolvulus galaticus, Crocus antalyensis, and Lilium candidum extracts show their antitumor activity through induction of p53-mediated apoptosis on human breast cancer cell line MCF-7 cells.

    Science.gov (United States)

    Tokgun, Onur; Akca, Hakan; Mammadov, Ramazan; Aykurt, Candan; Deniz, Gökhan

    2012-11-01

    Conventional and newly emerging treatment procedures such as chemotherapy, catalytic therapy, photodynamic therapy, and radiotherapy have not succeeded in reversing the outcome of cancer diseases to any drastic extent, which has led researchers to investigate alternative treatment options. The extensive repertoire of traditional medicinal knowledge systems from various parts of the world are being re-investigated for their healing properties. It has been reported that several members of the Convolvulaceae, Iridaceae, and Liliaceae families have antitumor activity against some tumor cell lines. Here we first report that Convolvulus galaticus, Crocus antalyensis, and Lilium candidum species have cytotoxic activity on human breast cancer cell line MCF-7 cells. Plant samples were collected and identified, and their cytotoxic effects on the MCF-7 cell line were examined at different concentrations of methanol extracts. We found that all three plants have cytotoxic effects on MCF-7 cells but that C. galaticus has the strongest cytotoxic effect even in the lowest extract concentration tested (0.32 μg/mL). Our results indicate that these plant extracts have cytotoxic effects on human breast carcinoma cell line MCF-7 cells and that this cytotoxic effect comes from p53-mediated stimulation of apoptosis.

  17. Gain-of-function p53 mutants co-opt chromatin pathways to drive cancer growth.

    Science.gov (United States)

    Zhu, Jiajun; Sammons, Morgan A; Donahue, Greg; Dou, Zhixun; Vedadi, Masoud; Getlik, Matthäus; Barsyte-Lovejoy, Dalia; Al-awar, Rima; Katona, Bryson W; Shilatifard, Ali; Huang, Jing; Hua, Xianxin; Arrowsmith, Cheryl H; Berger, Shelley L

    2015-09-10

    TP53 (which encodes p53 protein) is the most frequently mutated gene among all human cancers. Prevalent p53 missense mutations abrogate its tumour suppressive function and lead to a 'gain-of-function' (GOF) that promotes cancer. Here we show that p53 GOF mutants bind to and upregulate chromatin regulatory genes, including the methyltransferases MLL1 (also known as KMT2A), MLL2 (also known as KMT2D), and acetyltransferase MOZ (also known as KAT6A or MYST3), resulting in genome-wide increases of histone methylation and acetylation. Analysis of The Cancer Genome Atlas shows specific upregulation of MLL1, MLL2, and MOZ in p53 GOF patient-derived tumours, but not in wild-type p53 or p53 null tumours. Cancer cell proliferation is markedly lowered by genetic knockdown of MLL1 or by pharmacological inhibition of the MLL1 methyltransferase complex. Our study reveals a novel chromatin mechanism underlying the progression of tumours with GOF p53, and suggests new possibilities for designing combinatorial chromatin-based therapies for treating individual cancers driven by prevalent GOF p53 mutations.

  18. Prognostic Value of p53 Expression Intensity in Urothelial Cancers.

    Science.gov (United States)

    Qamar, Samina; Inam, Qazi Adil; Ashraf, Sobia; Khan, M Safdar; Khokhar, M Abbas; Awan, Nukhbatullah

    2017-04-01

    To determine association of immunohistochemical expression intensity of p53 with grade and stage of urothelial cancers. Descriptive cross-sectional analytical study. Pathology Department, King Edward Medical University, Lahore, from January to December 2016. Data of transurethral resection/radical cystesctomy urinary bladder biopsies was collected. Clinical, radiological and cystoscopic findings of patients were noted from patients' charts in the Urology Ward. Biopsies were graded histologically according to WHO 2004 grading system. TNM system was used for pathological staging. On selected slides, immunoshistochemistry for p53 was applied. Nuclear immunoreactivity was considered positive if present in >10% of tumor cells and negative if <10% of tumor cells. Intensity was considered weak (less than 15% cells) and strong (more than 15% cells). Data was analyzed by SPSS version 21. Linear-by-linear association was calculated between p53 expression and stage of urothelial tumors, Chi-Square test was used to see association between grade and intensity of p53. Qualitative variables, like grade and stage of carcinoma along with p53 expression, were calculated in terms of frequencies and percentages. P ≤ 0.05 was taken as significant. Out of the 70 patients, 61 (87%) were males and 9 (13%) females. Out of 25 low grade lesions, 4 (16%) cases were p53 positive; and out of 45 high grade lesions, 41 (91%) cases were p53 positive. There was 33% (2/6 cases) positivity in Tis, 55% (16/29 cases) in T1, 72% in T2 (21/29), and 100% in T3a (5/5 cases) and T3b (1/1 case). Strong intensity of p53 staining was noted to be 5.4% (n=25) of low grade and 94.6% (n=45) of high grade tumors. p53 expression was greater and more frequently strong in higher grade and stage of urothelial carcinoma. It can be used as a prognostic marker in predicting higher grade and stage of bladder cancer.

  19. 重组人腺病毒p53对裸鼠人胃癌细胞移植瘤的抑制效果及不良反应%The curative effects and side effects of recombinant human adenovirus p53 on transplanted gastric cancer cells in nude mice

    Institute of Scientific and Technical Information of China (English)

    谢忆山; 伍龙; 刘少平; 彭春伟; 李雁

    2013-01-01

    目的 探讨重组人腺病毒p53(rAd-p53)对胃癌细胞裸鼠移植瘤的抗肿瘤效应及相关不良反应.方法 将胃癌细胞SGC-7901注射于裸鼠皮下制成动物模型,分别用rAd-p53和盐酸表阿霉素(EPI)进行治疗.rAd-p53治疗组剂量为10μl浓度1012vp/ml,EPI治疗组剂量为1.25mg/kg,各组每3周给药7次,以生理盐水为对照组.结果 与对照组比较,rAd-p53治疗组和EPI治疗组肿瘤抑制率分别为80%和60%,差异有统计学意义(P<0.01);rAd-p53和EPI治疗组之间比较差异无统计学意义(P>0.05).没有实验动物死亡,rAd-p53治疗组2只裸鼠出现肝脏不良反应,EPI治疗组1只裸鼠心脏不良反应,上述反应均有病理学观察证实.结论 裸鼠体内实验证实rAd-p53对胃癌细胞具有抗肿瘤效应,但应注意其肝脏不良反应.%Objective To investigate the inhibitory and side effects of recombinant Adenoviruswtp53 (tAd-p53) SGC-7901 on gastric cancer cells in vivo.Methods SGC-7901 cells were subcutaneously injected into the nude mice to establish xenograph models,which were treated with Gendicine,a recombinant human Ad-p53 injection (rAd-p53),and epirubicin hydrochloride (EPI),a cytotoxic chemotherapy agent.Results As compared with the blank control,treatment with rAd-p53 at the dose of 10 μl of 1012 vp/ml and EPI at the dose of 1.25 mg/kg,7 times every 3 weeks,resulted in 80% and 60% of tumor growth inhibition,respectively.The difference in rAd-p53 and EPI therapy group was not statistically significant.No animal death was observed,although 2 nude mice in rAd-p53 group developed liver toxicity and 1 nude mouse in EPI group developed cardiac toxicity,and the results were validated histopathologically.Conclusion The rAd-p53 has tumor inhibitory effect on gastric cancer cells,but the liver toxicity should be considered seriously.

  20. Small-molecule MDM2 antagonists reveal aberrant p53 signaling in cancer: implications for therapy.

    Science.gov (United States)

    Tovar, Christian; Rosinski, James; Filipovic, Zoran; Higgins, Brian; Kolinsky, Kenneth; Hilton, Holly; Zhao, Xiaolan; Vu, Binh T; Qing, Weiguo; Packman, Kathryn; Myklebost, Ola; Heimbrook, David C; Vassilev, Lyubomir T

    2006-02-07

    The p53 tumor suppressor retains its wild-type conformation and transcriptional activity in half of all human tumors, and its activation may offer a therapeutic benefit. However, p53 function could be compromised by defective signaling in the p53 pathway. Using a small-molecule MDM2 antagonist, nutlin-3, to probe downstream p53 signaling we find that the cell-cycle arrest function of the p53 pathway is preserved in multiple tumor-derived cell lines expressing wild-type p53, but many have a reduced ability to undergo p53-dependent apoptosis. Gene array analysis revealed attenuated expression of multiple apoptosis-related genes. Cancer cells with mdm2 gene amplification were most sensitive to nutlin-3 in vitro and in vivo, suggesting that MDM2 overexpression may be the only abnormality in the p53 pathway of these cells. Nutlin-3 also showed good efficacy against tumors with normal MDM2 expression, suggesting that many of the patients with wild-type p53 tumors may benefit from antagonists of the p53-MDM2 interaction.

  1. p53 orchestrates between normal differentiation and cancer.

    Science.gov (United States)

    Rivlin, Noa; Koifman, Gabriela; Rotter, Varda

    2015-06-01

    During recent years, it is becoming more and more evident that there is a tight connection between abnormal differentiation processes and cancer. While cancer and stem cells are very different, especially in terms of maintaining genomic integrity, these cell types also share many similar properties. In this review, we aim to provide an over-view of the roles of the key tumor suppressor, p53, in regulating normal differentiation and function of both stem cells and adult cells. When these functions are disrupted, undifferentiated cells may become transformed. Understanding the function of p53 in stem cells and its role in maintaining the balance between differentiation and malignant transformation can help shed light on cancer initiation and propagation, and hopefully also on cancer prevention and therapy.

  2. Gene expression patterns associated with p53 status in breast cancer

    Directory of Open Access Journals (Sweden)

    He Xiaping

    2006-12-01

    Full Text Available Abstract Background Breast cancer subtypes identified in genomic studies have different underlying genetic defects. Mutations in the tumor suppressor p53 occur more frequently in estrogen receptor (ER negative, basal-like and HER2-amplified tumors than in luminal, ER positive tumors. Thus, because p53 mutation status is tightly linked to other characteristics of prognostic importance, it is difficult to identify p53's independent prognostic effects. The relation between p53 status and subtype can be better studied by combining data from primary tumors with data from isogenic cell line pairs (with and without p53 function. Methods The p53-dependent gene expression signatures of four cell lines (MCF-7, ZR-75-1, and two immortalized human mammary epithelial cell lines were identified by comparing p53-RNAi transduced cell lines to their parent cell lines. Cell lines were treated with vehicle only or doxorubicin to identify p53 responses in both non-induced and induced states. The cell line signatures were compared with p53-mutation associated genes in breast tumors. Results Each cell line displayed distinct patterns of p53-dependent gene expression, but cell type specific (basal vs. luminal commonalities were evident. Further, a common gene expression signature associated with p53 loss across all four cell lines was identified. This signature showed overlap with the signature of p53 loss/mutation status in primary breast tumors. Moreover, the common cell-line tumor signature excluded genes that were breast cancer subtype-associated, but not downstream of p53. To validate the biological relevance of the common signature, we demonstrated that this gene set predicted relapse-free, disease-specific, and overall survival in independent test data. Conclusion In the presence of breast cancer heterogeneity, experimental and biologically-based methods for assessing gene expression in relation to p53 status provide prognostic and biologically-relevant gene

  3. cDNA sequencing improves the detection of P53 missense mutations in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Jesionek-Kupnicka Dorota

    2009-08-01

    Full Text Available Abstract Background Recently published data showed discrepancies beteween P53 cDNA and DNA sequencing in glioblastomas. We hypothesised that similar discrepancies may be observed in other human cancers. Methods To this end, we analyzed 23 colorectal cancers for P53 mutations and gene expression using both DNA and cDNA sequencing, real-time PCR and immunohistochemistry. Results We found P53 gene mutations in 16 cases (15 missense and 1 nonsense. Two of the 15 cases with missense mutations showed alterations based only on cDNA, and not DNA sequencing. Moreover, in 6 of the 15 cases with a cDNA mutation those mutations were difficult to detect in the DNA sequencing, so the results of DNA analysis alone could be misinterpreted if the cDNA sequencing results had not also been available. In all those 15 cases, we observed a higher ratio of the mutated to the wild type template by cDNA analysis, but not by the DNA analysis. Interestingly, a similar overexpression of P53 mRNA was present in samples with and without P53 mutations. Conclusion In terms of colorectal cancer, those discrepancies might be explained under three conditions: 1, overexpression of mutated P53 mRNA in cancer cells as compared with normal cells; 2, a higher content of cells without P53 mutation (normal cells and cells showing K-RAS and/or APC but not P53 mutation in samples presenting P53 mutation; 3, heterozygous or hemizygous mutations of P53 gene. Additionally, for heterozygous mutations unknown mechanism(s causing selective overproduction of mutated allele should also be considered. Our data offer new clues for studying discrepancy in P53 cDNA and DNA sequencing analysis.

  4. Expression of survivin and p53 modulates honokiol-induced apoptosis in colorectal cancer cells.

    Science.gov (United States)

    Lai, Ying-Jiun; Lin, Chien-I; Wang, Chia-Lin; Chao, Jui-I

    2014-11-01

    Honokiol is a small biphenolic compound, which exerts antitumor activities; however, the precise mechanism of honokiol-induced apoptosis in the human colorectal cancer cells remains unclear. Here, we show that survivin and p53 display the opposite role on the regulation of honokiol-induced apoptosis in the human colorectal cancer cells. Honokiol induced the cell death and apoptosis in various colorectal cancer cell lines. Moreover, honokiol elicited the extrinsic death receptor pathway of DR5 and caspase 8 and the intrinsic pathway of caspase 9. The common intrinsic and extrinsic downstream targets of activated caspase 3 and PARP protein cleavage were induced by honokiol. Interestingly, honokiol reduced anti-apoptotic survivin protein and gene expression. Transfection with a green fluorescent protein (GFP)-survivin-expressed vector increased the colorectal cancer cell viability and resisted the honokiol-induced apoptosis. Meantime, honokiol increased total p53 and the phosphorylated p53 proteins at Ser15 and Ser46. The p53-wild type colorectal cancer cells were exhibited greater cytotoxicity, apoptosis and survivin reduction than the p53-null cancer cells after treatment with honokiol. Together, these findings demonstrate that the existence of survivin and p53 can modulate the honokiol-induced apoptosis in the human colorectal cancer cells.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  6. Association of p53 codon 72 polymorphism with liver metastases of colorectal cancers positive for p53 overexpression

    Institute of Scientific and Technical Information of China (English)

    Zhong-zheng ZHU; Bing LIU; Ai-zhong WANG; Hang-ruo JIA; Xia-xiang JIN; Xiang-lei HE; Li-fang HOU; Guan-shan ZHU

    2008-01-01

    Objective: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. Methods: The p53 R72P genotype was identified by polymerase chain reaction-restriction fi'agment length poly-morphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectai cancer. Results: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence inter-val)=1.05~4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02~11.72) and a 1.05-fold (95% CI=0.36~3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. Conclusion: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression.

  7. Adiposity is associated with p53 gene mutations in breast cancer.

    Science.gov (United States)

    Ochs-Balcom, Heather M; Marian, Catalin; Nie, Jing; Brasky, Theodore M; Goerlitz, David S; Trevisan, Maurizio; Edge, Stephen B; Winston, Janet; Berry, Deborah L; Kallakury, Bhaskar V; Freudenheim, Jo L; Shields, Peter G

    2015-10-01

    Mutations in the p53 gene are among the most frequent genetic events in human cancer and may be triggered by environmental and occupational exposures. We examined the association of clinical and pathological characteristics of breast tumors and breast cancer risk factors according to the prevalence and type of p53 mutations. Using tumor blocks from incident cases from a case-control study in western New York, we screened for p53 mutations in exons 2-11 using the Affymetrix p53 Gene Chip array and analyzed case-case comparisons using logistic regression. The p53 mutation frequency among cases was 28.1 %; 95 % were point mutations (13 % of which were silent) and the remainder were single base pair deletions. Sixty seven percent of all point mutations were transitions; 24 % of them are G:C>A:T at CpG sites. Positive p53 mutation status was associated with poorer differentiation (OR, 95 % CI 2.29, 1.21-4.32), higher nuclear grade (OR, 95 % CI 1.99, 1.22-3.25), and increased Ki-67 status (OR, 95 % CI 1.81, 1.10-2.98). Cases with P53 mutations were more likely to have a combined ER-positive and PR-negative status (OR, 95 % CI 1.65, 1.01-2.71), and a combined ER-negative and PR-negative status (OR, 95 % CI 2.18, 1.47-3.23). Body mass index >30 kg/m(2), waist circumference >79 cm, and waist-to-hip ratio >0.86 were also associated with p53 status; obese breast cancer cases are more likely to have p53 mutations (OR, 95 % CI 1.78, 1.19-2.68). We confirmed that p53 mutations are associated with less favorable tumor characteristics and identified an association of p53 mutation status and adiposity.

  8. Stathmin regulates mutant p53 stability and transcriptional activity in ovarian cancer.

    Science.gov (United States)

    Sonego, Maura; Schiappacassi, Monica; Lovisa, Sara; Dall'Acqua, Alessandra; Bagnoli, Marina; Lovat, Francesca; Libra, Massimo; D'Andrea, Sara; Canzonieri, Vincenzo; Militello, Loredana; Napoli, Marco; Giorda, Giorgio; Pivetta, Barbara; Mezzanzanica, Delia; Barbareschi, Mattia; Valeri, Barbara; Canevari, Silvana; Colombatti, Alfonso; Belletti, Barbara; Del Sal, Giannino; Baldassarre, Gustavo

    2013-05-01

    Stathmin is a p53-target gene, frequently overexpressed in late stages of human cancer progression. Type II High Grade Epithelial Ovarian Carcinomas (HG-EOC) represents the only clear exception to this observation. Here, we show that stathmin expression is necessary for the survival of HG-EOC cells carrying a p53 mutant (p53(MUT) ) gene. At molecular level, stathmin favours the binding and the phosphorylation of p53(MUT) by DNA-PKCS , eventually modulating p53(MUT) stability and transcriptional activity. Inhibition of stathmin or DNA-PKCS impaired p53(MUT) -dependent transcription of several M phase regulators, resulting in M phase failure and EOC cell death, both in vitro and in vivo. In primary human EOC a strong correlation exists between stathmin, DNA-PKCS , p53(MUT) overexpression and its transcriptional targets, further strengthening the relevance of the new pathway here described. Overall our data support the hypothesis that the expression of stathmin and p53 could be useful for the identification of high risk patients that will benefit from a therapy specifically acting on mitotic cancer cells.

  9. The presence of the intron 3 16 bp duplication polymorphism of p53 (rs17878362) in breast cancer is associated with a low Δ40p53:p53 ratio and better outcome.

    Science.gov (United States)

    Morten, Brianna C; Wong-Brown, Michelle W; Scott, Rodney J; Avery-Kiejda, Kelly A

    2016-01-01

    Breast cancer is the most common female cancer, but it has relatively low rates of p53 mutations, suggesting other mechanisms are responsible for p53 inactivation. We have shown that the p53 isoform, Δ40p53, is highly expressed in breast cancer, where it may contribute to p53 inactivation. Δ40p53 can be produced by alternative splicing of p53 in intron 2 and this is regulated by the formation of G-quadruplex structures in p53 intron 3, from which the nucleotides forming these structures overlap with a common polymorphism, rs17878362. rs17878362 alters p53 splicing to decrease fully spliced p53 messenger RNA (mRNA) in vitro following ionizing radiation and this in turn alters Δ40p53:p53. Hence, the presence of rs17878362 may be important in regulating Δ40p53:p53 in breast cancer. This study aimed to determine if rs17878362 was associated with altered Δ40p53 and p53 expression and outcome in breast cancer. We sequenced p53 in breast tumours from 139 patients and compared this with Δ40p53 and p53 mRNA expression. We found that the ratio of Δ40p53:p53 was significantly lower in tumours homozygous for the polymorphic A2 allele compared with those who were wild-type (A1/A1). Furthermore, there was a lower proportion of breast cancers carrying the A2 allele from patients who subsequently developed metastasis compared with those that did not. Finally, we show that patients whose tumours carried the polymorphic A2 allele had significantly better disease-free survival. These results show that rs17878362 is associated with a low Δ40p53:p53 ratio in breast cancer and that this is associated with better outcome.

  10. Interaction of Werner and Bloom syndrome genes with p53 in familial breast cancer.

    Science.gov (United States)

    Wirtenberger, Michael; Frank, Bernd; Hemminki, Kari; Klaes, Rüdiger; Schmutzler, Rita K; Wappenschmidt, Barbara; Meindl, Alfons; Kiechle, Marion; Arnold, Norbert; Weber, Bernhard H F; Niederacher, Dieter; Bartram, Claus R; Burwinkel, Barbara

    2006-08-01

    Mutations of the human RecQ helicase genes WRN and BLM lead to rare autosomal recessive disorders, Werner and Bloom syndromes, which are associated with premature ageing and cancer predisposition. We tested the hypothesis whether three polymorphic, non-conservative amino acid exchanges in WRN and BLM act as low-penetrance familial breast cancer risk factors. Moreover, we examined the putative impact of p53 MspI 1798G>A, which is completely linked to p53PIN3, a 16 bp insertion/duplication that has been associated with reduced p53 expression, on familial breast cancer risk. Genotyping analyses, performed on 816 BRCA1/2 mutation-negative German familial breast cancer patients and 1012 German controls, revealed a significant association of the WRN Cys1367Arg polymorphism with familial breast cancer (OR = 1.28, 95% CI 1.06-1.54) and high-risk familial breast cancer (OR = 1.32, 95% CI 1.06-1.65). The analysis of p53 MspI 1798G>A, which is completely linked to p53PIN3, showed a significantly increased familial breast cancer risk for carriers of the 16 bp insertion/duplication, following a recessive mode (OR = 2.15, 95% CI = 1.12-4.11). WRN Cys1367Arg, located in the C-terminus, the binding site of p53, is predicted to be damaging. The joint effect of WRN Cys1367Arg and p53 MspI resulted in an increased breast cancer risk compared to the single polymorphisms (OR = 3.39, 95% CI 1.19-9.71). In conclusion, our study indicates the importance of inherited variants in the WRN and p53 genes for familial breast cancer susceptibility.

  11. Preferential Formation of Benzo[a]pyrene Adducts at Lung Cancer Mutational Hotspots in P53

    Science.gov (United States)

    Denissenko, Mikhail F.; Pao, Annie; Tang, Moon-Shong; Pfeifer, Gerd P.

    1996-10-01

    Cigarette smoke carcinogens such as benzo[a]pyrene are implicated in the development of lung cancer. The distribution of benzo[a]pyrene diol epoxide (BPDE) adducts along exons of the P53 gene in BPDE-treated HeLa cells and bronchial epithelial cells was mapped at nucleotide resolution. Strong and selective adduct formation occurred at guanine positions in codons 157, 248, and 273. These same positions are the major mutational hotspots in human lung cancers. Thus, targeted adduct formation rather than phenotypic selection appears to shape the P53 mutational spectrum in lung cancer. These results provide a direct etiological link between a defined chemical carcinogen and human cancer.

  12. [Structural organization of the human p53 gene. I. Molecular cloning of the human p53 gene].

    Science.gov (United States)

    Bukhman, V L; Ninkina, N N; Chumakov, P M; Khilenkova, M A; Samarina, O P

    1987-09-01

    Human p53 gene was cloned from the normal human placenta DNA and DNA from the strain of human kidney carcinoma transplanted into nude mice. Representative gene library from tumor strain of human kidney carcinoma and library of 15 kb EcoRI fragments of DNA from normal human placenta were constructed. Maniatis gene library was also used. Five clones were isolated from kidney carcinoma library; they covered 27 kb and included full-length p53 gene of 19.5 kb and flanking sequences. From normal placenta libraries three overlapped clones were obtained. Restriction map of cloned sequences was constructed and polarity of the p53 gene determined. The first intron of the gene is large (10.4 kb); polymorphic BglII site was observed in this intron, which allows to discriminate between allelic genes. One of these (BglII-) is ten times more abundant that the other (BglII+). Both allelic genes are able to synthesize the 2.8 kb p53 gene.

  13. Human Immunodeficiency Virus Type 1 Nef Binds to Tumor Suppressor p53 and Protects Cells against p53-Mediated Apoptosis

    OpenAIRE

    2002-01-01

    The nef gene product of human immunodeficiency virus type 1 (HIV-1) is important for the induction of AIDS, and key to its function is its ability to manipulate T-cell function by targeting cellular signal transduction proteins. We reported that Nef coprecipitates a multiprotein complex from cells which contains tumor suppressor protein p53. We now show that Nef interacts directly with p53. Binding assays showed that an N-terminal, 57-residue fragment of Nef (Nef 1-57) contains the p53-bindin...

  14. ATF3 activates Stat3 phosphorylation through inhibition of p53 expression in skin cancer cells.

    Science.gov (United States)

    Hao, Zhen-Feng; Ao, Jun-Hong; Zhang, Jie; Su, You-Ming; Yang, Rong-Ya

    2013-01-01

    ATF3, a member of the ATF/CREB family of transcription factors, has been found to be selectively induced by calcineurin/NFAT inhibition and to enhance keratinocyte tumor formation, although the precise role of ATF3 in human skin cancer and possible mechanisms remain unknown. In this study, clinical analysis of 30 skin cancer patients and 30 normal donors revealed that ATF3 was accumulated in skin cancer tissues. Functional assays demonstrated that ATF3 significantly promoted skin cancer cell proliferation. Mechanically, ATF3 activated Stat3 phosphorylation in skin cancer cell through regulation of p53 expression. Moreover, the promotion effect of ATF3 on skin cancer cell proliferation was dependent on the p53-Stat3 signaling cascade. Together, the results indicate that ATF3 might promote skin cancer cell proliferation and enhance skin keratinocyte tumor development through inhibiting p53 expression and then activating Stat3 phosphorylation.

  15. The role of p53 and pRB in apoptosis and cancer

    DEFF Research Database (Denmark)

    Hickman, Emma S; Moroni, M Cristina; Helin, Kristian

    2002-01-01

    Loss of function of both the p53 pathway and the retinoblastoma protein (pRB) pathway plays a significant role in the development of most human cancers. Loss of pRB results in deregulated cell proliferation and apoptosis, whereas loss of p53 desensitizes cells to checkpoint signals, including...... apoptosis. In the past two years, mouse genetics and gene expression profiling have led to major advances in our understanding of how the pRB and p53 pathways regulate apoptosis and thus the development of tumours....

  16. New Insights into p53 Signaling and Cancer Cell Response to DNA Damage: Implications for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Razmik Mirzayans

    2012-01-01

    Full Text Available Activation of the p53 signaling pathway by DNA-damaging agents was originally proposed to result either in cell cycle checkpoint activation to promote survival or in apoptotic cell death. This model provided the impetus for numerous studies focusing on the development of p53-based cancer therapies. According to recent evidence, however, most p53 wild-type human cell types respond to ionizing radiation by undergoing stress-induced premature senescence (SIPS and not apoptosis. SIPS is a sustained growth-arrested state in which cells remain viable and secrete factors that may promote cancer growth and progression. The p21WAF1 (hereafter p21 protein has emerged as a key player in the p53 pathway. In addition to its well-studied role in cell cycle checkpoints, p21 regulates p53 and its upstream kinase (ATM, controls gene expression, suppresses apoptosis, and induces SIPS. Herein, we review these and related findings with human solid tumor-derived cell lines, report new data demonstrating dynamic behaviors of p53 and p21 in the DNA damage response, and examine the gain-of-function properties of cancer-associated p53 mutations. We point out obstacles in cancer-therapeutic strategies that are aimed at reactivating the wild-type p53 function and highlight some alternative approaches that target the apoptotic threshold in cancer cells with differing p53 status.

  17. The state of the p53 and retinoblastoma genes in human cervical carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Scheffner, M.; Muenger, K.; Byrne, J.C.; Howley, P.M. (National Cancer Inst., Bethesda, MD (United States))

    1991-07-01

    Human cervical carcinoma cell lines that were either positive or negative for human papillomavirus (HPV) DNA sequences were analyzed for evidence of mutation of the p53 and retinoblastoma genes. Each of five HPV-positive cervical cancer cell lines expressed normal pRB and low levels of wild-type p53 proteins, which are presumed to be altered in function as a consequence of association with HPV E7 and E6 oncoproteins, respectively. In contrast, mutations were identified in the p53 and RB genes expressed in the C-33A and HT-3 cervical cancer cell lines, which lack HPV DNA sequences. Mutations in the p53 genes mapped to codon 273 and codon 245 in the C33-A and HT-3 cell lines, respectively, located in the highly conserved regions of p53, where mutations appear in a variety of human cancers. Mutations in RB occurred at splice junctions, resulting in in-frame deletions, affecting exons 13 and 20 in the HT-3 and C-33A cell lines, respectively. These mutations resulted in aberrant proteins that were not phosphorylated and were unable to complex with the adenovirus E1A oncoprotein. These results support the hypothesis that the inactivation of the normal functions of the tumor-suppressor proteins pRB and p53 are important steps in human cervical carcinogenesis, either by mutation or from complex formation with the HPV E6 and E7 oncoproteins.

  18. Morphological Heterogeneity of p53 Positive and p53 Negative Nuclei in Breast Cancers Stratified by Clinicopathological Variables

    Directory of Open Access Journals (Sweden)

    Katrin Friedrich

    1997-01-01

    Full Text Available The study was aimed to detect differences in nuclear morphology between nuclear populations as well as between tumours with different p53 expression in breast cancers with different clinicopathological features, which also reflect the stage of tumour progression. The p53 immunohistochemistry was performed on paraffin sections from 88 tumour samples. After the cells had been localised by means of an image cytometry workstation and their immunostaining had been categorised visually, the sections were destained and stained by the Feulgen protocol. The nuclei were relocated and measured cytometrically by the workstation.

  19. Propofol induces proliferation partially via downregulation of p53 protein and promotes migration via activation of the Nrf2 pathway in human breast cancer cell line MDA-MB-231.

    Science.gov (United States)

    Meng, Chao; Song, Linlin; Wang, Juan; Li, Di; Liu, Yanhong; Cui, Xiaoguang

    2017-02-01

    Antioxidants induce the proliferation of cancers by decreasing the expression of p53. Propofol, one of the most extensively used intravenous anesthetics, provides its antioxidative activity via activation of the nuclear factor E2-related factor-2 (Nrf2) pathway, but the mechanisms involved in the effects remain unknown. Thus, we aimed to investigate the function of p53 and Nrf2 in the human breast cancer cell line MDA-MB-231 following treatment with propofol. The cells were treated with propofol (2, 5 and 10 µg/ml) for 1, 4 and 12 h, and MTT assay was used to evaluate cell proliferation, and a wound healing assay was used to evaluate cell migration. Cell apoptosis, caspase-3 activity, and western blot analysis for p53 and Nrf2 protein were also assessed. Finally, PIK-75, a potent Nrf2 inhibitor, was used to confirm the effects of Nrf2 after treatment with propofol. Treatment of MDA-MB‑231 cells with propofol resulted in increased proliferation and migration in a dose- and time-dependent manner. After treatment with propofol for 12 h, the Nrf2 protein expression was increased, while the percentage of apoptotic cells, caspase-3 activity, and expression of p53 were significantly decreased. Additionally, treatment with the Nrf2 inhibitor increased the percentage of apoptotic cells, inhibited the migration almost completely, and decreased the degree of proliferation, while the expression of p53 was not affected. In conclusion, propofol increased the proliferation of human breast cancer MDA-MB‑231 cells, which was at least partially associated with the inhibition of the expression of p53, and induced cell migration, which was involved in the activation of the Nrf2 pathway.

  20. p53 is required for metformin-induced growth inhibition, senescence and apoptosis in breast cancer cells.

    Science.gov (United States)

    Li, Puyu; Zhao, Ming; Parris, Amanda B; Feng, Xiaoshan; Yang, Xiaohe

    2015-09-04

    The p53 tumor repressor gene is commonly mutated in human cancers. The tumor inhibitory effect of metformin on p53-mutated breast cancer cells remains unclear. Data from the present study demonstrated that p53 knockdown or mutation has a negative effect on metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. We also found that p53 reactivating agent nutlin-3α and CP/31398 promoted metformin-induced growth inhibition, senescence and apoptosis in MCF-7 (wt p53) and MDA-MB-231 (mt p53) cells, respectively. Treatment of MCF-7 cells with metformin or phenformin induced increase in p53 protein levels and the transcription of its downstream target genes, Bax and p21, in a dose-dependent manner. Moreover, we demonstrated that AMPK-mTOR signaling played a role in metformin-induced p53 up-regulation. The present study showed that p53 is required for metformin or phenformin-induced growth inhibition, senescence and apoptosis in breast cancer cells. The combination of metformin with p53 reactivating agents, like nutlin-3α and CP/31398, is a promising strategy for improving metformin-mediated anti-cancer therapy, especially for tumors with p53 mutations.

  1. Wnt-responsive cancer stem cells are located close to distorted blood vessels and not in hypoxic regions in a p53-null mouse model of human breast cancer.

    Science.gov (United States)

    Vadakkan, Tegy J; Landua, John D; Bu, Wen; Wei, Wei; Li, Fuhai; Wong, Stephen T C; Dickinson, Mary E; Rosen, Jeffrey M; Lewis, Michael T; Zhang, Mei

    2014-07-01

    Cancer stem cells (CSCs, or tumor-initiating cells) may be responsible for tumor formation in many types of cancer, including breast cancer. Using high-resolution imaging techniques, we analyzed the relationship between a Wnt-responsive, CSC-enriched population and the tumor vasculature using p53-null mouse mammary tumors transduced with a lentiviral Wnt signaling reporter. Consistent with their localization in the normal mammary gland, Wnt-responsive cells in tumors were enriched in the basal/myoepithelial population and generally located in close proximity to blood vessels. The Wnt-responsive CSCs did not colocalize with the hypoxia-inducible factor 1α-positive cells in these p53-null basal-like tumors. Average vessel diameter and vessel tortuosity were increased in p53-null mouse tumors, as well as in a human tumor xenograft as compared with the normal mammary gland. The combined strategy of monitoring the fluorescently labeled CSCs and vasculature using high-resolution imaging techniques provides a unique opportunity to study the CSC and its surrounding vasculature.

  2. Radiosensitivity in lung cancer with focus on p53

    CERN Document Server

    Bergqvist, M

    2002-01-01

    In Sweden approximately 2800 new lung cancer patients are diagnosed every year. Radiotherapy is used with curative intention in certain groups of patients. The aim of this thesis is to study the basis of differences in radioresistance and the possibility to predict response to radiotherapy. In the first study we investigated, using the comet assay, four lung cancer cell lines with different sensitivity towards radiation. A clear dose-response relationship for radiation-induced DNA single strand and double strand breaks were found. All cell lines showed a remarkably efficient repair of both the DNA single strand and double strand breaks one hour after irradiation. However, further studies in one radioresistant and one radiosensitive cell line demonstrated that repair during the first 15 min had the best accordance with radiosensitivity measured as surviving fraction. In the second and third study, sequencing studies of the p53 gene were performed on cell lines as well as on tumour material. Cell lines that wer...

  3. Mutual interactions between P53 and growth factors in cancer

    NARCIS (Netherlands)

    Asschert, JGW; Vellenga, E; De Jong, S; De Vries, EGE

    1998-01-01

    The function of p53 armour suppressor protein is determined by various intrinsic properties of the protein. The effect of p53 DNA-binding, and platein-protein interactions are determined by the conformation of the protein. Thus p53 fulfils its role in cell cycle control and the onset of apoptotic ce

  4. Bioinformatics Study of Cancer-Related Mutations within p53 Phosphorylation Site Motifs

    Directory of Open Access Journals (Sweden)

    Xiaona Ji

    2014-07-01

    Full Text Available p53 protein has about thirty phosphorylation sites located at the N- and C-termini and in the core domain. The phosphorylation sites are relatively less mutated than other residues in p53. To understand why and how p53 phosphorylation sites are rarely mutated in human cancer, using a bioinformatics approaches, we examined the phosphorylation site and its nearby flanking residues, focusing on the consensus phosphorylation motif pattern, amino-acid correlations within the phosphorylation motifs, the propensity of structural disorder of the phosphorylation motifs, and cancer mutations observed within the phosphorylation motifs. Many p53 phosphorylation sites are targets for several kinases. The phosphorylation sites match 17 consensus sequence motifs out of the 29 classified. In addition to proline, which is common in kinase specificity-determining sites, we found high propensity of acidic residues to be adjacent to phosphorylation sites. Analysis of human cancer mutations in the phosphorylation motifs revealed that motifs with adjacent acidic residues generally have fewer mutations, in contrast to phosphorylation sites near proline residues. p53 phosphorylation motifs are mostly disordered. However, human cancer mutations within phosphorylation motifs tend to decrease the disorder propensity. Our results suggest that combination of acidic residues Asp and Glu with phosphorylation sites provide charge redundancy which may safe guard against loss-of-function mutations, and that the natively disordered nature of p53 phosphorylation motifs may help reduce mutational damage. Our results further suggest that engineering acidic amino acids adjacent to potential phosphorylation sites could be a p53 gene therapy strategy.

  5. Mutant p53-associated myosin-X upregulation promotes breast cancer invasion and metastasis.

    Science.gov (United States)

    Arjonen, Antti; Kaukonen, Riina; Mattila, Elina; Rouhi, Pegah; Högnäs, Gunilla; Sihto, Harri; Miller, Bryan W; Morton, Jennifer P; Bucher, Elmar; Taimen, Pekka; Virtakoivu, Reetta; Cao, Yihai; Sansom, Owen J; Joensuu, Heikki; Ivaska, Johanna

    2014-03-01

    Mutations of the tumor suppressor TP53 are present in many forms of human cancer and are associated with increased tumor cell invasion and metastasis. Several mechanisms have been identified for promoting dissemination of cancer cells with TP53 mutations, including increased targeting of integrins to the plasma membrane. Here, we demonstrate a role for the filopodia-inducing motor protein Myosin-X (Myo10) in mutant p53-driven cancer invasion. Analysis of gene expression profiles from 2 breast cancer data sets revealed that MYO10 was highly expressed in aggressive cancer subtypes. Myo10 was required for breast cancer cell invasion and dissemination in multiple cancer cell lines and murine models of cancer metastasis. Evaluation of a Myo10 mutant without the integrin-binding domain revealed that the ability of Myo10 to transport β₁ integrins to the filopodia tip is required for invasion. Introduction of mutant p53 promoted Myo10 expression in cancer cells and pancreatic ductal adenocarcinoma in mice, whereas suppression of endogenous mutant p53 attenuated Myo10 levels and cell invasion. In clinical breast carcinomas, Myo10 was predominantly expressed at the invasive edges and correlated with the presence of TP53 mutations and poor prognosis. These data indicate that Myo10 upregulation in mutant p53-driven cancers is necessary for invasion and that plasma-membrane protrusions, such as filopodia, may serve as specialized metastatic engines.

  6. CD8 T-cell responses against cyclin B1 in breast cancer patients with tumors overexpressing p53

    DEFF Research Database (Denmark)

    Sørensen, Rikke Baek; Andersen, Rikke Sick; Svane, Inge Marie;

    2009-01-01

    CD8 T-cell response against at least one of the peptides; strongest reactivity was detected against the CB9L2 peptide. Because the level of cyclin B1 has been shown to be influenced by the level of p53, which in turn is elevated in cancer cells because of point mutation, we analyzed the level of p53....... CONCLUSIONS: Our data support the notion of cyclin B1 as a prominent target for immunologic recognition in cancer patients harboring p53-mutated cancer cells. Because mutation of p53 is one of the most frequent genetic alterations in human cancers, this suggests that immunotherapy based on targeting of cyclin...... protein in biopsies from the patients by immune histochemistry. Combined data showed that anti-cyclin B1 reactivity was predominantly detected in patients with tumors characterized by elevated expression of p53. Interestingly, no reactivity was detected against six peptides derived from the p53 protein...

  7. Genome-wide analysis of the human p53 transcriptional network unveils a lncRNA tumour suppressor signature.

    Science.gov (United States)

    Sánchez, Yolanda; Segura, Victor; Marín-Béjar, Oskar; Athie, Alejandro; Marchese, Francesco P; González, Jovanna; Bujanda, Luis; Guo, Shuling; Matheu, Ander; Huarte, Maite

    2014-12-19

    Despite the inarguable relevance of p53 in cancer, genome-wide studies relating endogenous p53 activity to the expression of lncRNAs in human cells are still missing. Here, by integrating RNA-seq with p53 ChIP-seq analyses of a human cancer cell line under DNA damage, we define a high-confidence set of 18 lncRNAs that are p53 transcriptional targets. We demonstrate that two of the p53-regulated lncRNAs are required for the efficient binding of p53 to some of its target genes, modulating the p53 transcriptional network and contributing to apoptosis induction by DNA damage. We also show that the expression of p53-lncRNAs is lowered in colorectal cancer samples, constituting a tumour suppressor signature with high diagnostic power. Thus, p53-regulated lncRNAs establish a positive regulatory feedback loop that enhances p53 tumour suppressor activity. Furthermore, the signature defined by p53-regulated lncRNAs supports their potential use in the clinic as biomarkers and therapeutic targets.

  8. Notch-1 gene silencing promotes phosphorylations of JNK1 and p53 in human breast cancer MCF-7 cells%沉默Notch1基因促进人乳腺癌MCF-7细胞JNK1和p53磷酸化

    Institute of Scientific and Technical Information of China (English)

    袁磊; 陈旭东; 范文娟; 杨旭光; 王建国

    2013-01-01

    目的:探究沉默Notch1基因对人乳腺癌MCF-7细胞JNK1和p53磷酸化的影响.方法:选取人乳腺癌MCF-7细胞作为研究对象,构建shRNA-Notch1真核表达质粒用于转染MCF-7细胞使Notch1基因沉默.采用Western blotting方法检测MCF-7细胞Notch1、Hes-1、PUMA和NOXA蛋白的表达,JNK1和p53蛋白磷酸化水平以及caspase-3活化水平的改变.应用流式细胞术检测细胞凋亡和线粒体膜电位的变化.结果:人乳腺癌MCF-7细胞Notch1基因被沉默后,Notch1和Hes-1蛋白表达量明显减少(P<0.01),细胞凋亡率显著升高(P<0.01),JNK1和p53的磷酸化水平明显高于对照组(P<0.01),PUMA和NOXA表达量显著升高(P<0.05),cleaved caspase-3蛋白明显多于对照组(P<0.01),线粒体膜电位明显下降(P<0.05).结论:沉默Notch1基因可能通过激活JNK1信号通路活化p53,促进PUMA和NOXA蛋白表达,进而通过线粒体途径导致人乳腺癌MCF-7细胞凋亡.%AIM:To investigate the effect of Notch1 gene silencing on phosphorylations of JNK1 and p53 in human breast cancer MCF-7 cells.METHODS:shRNA-Notch1 eukaryotic expression plasmid was constructed and transfected into MCF-7 cells.The expression of Notch1 and Hes-1 was observed by Western blotting after transfction.Apoptosis and mitochondrial membrane potential were detected by flow cytometry.Western blotting was also used to determine the protein levels of p-JNK1,p-p53,PUMA,NOXA and cleaved caspase-3 after Notch1 silencing was performed in MCF-7 cells.RESULTS:Silencing of Notch1 significantly reduced the expression of Notch1 and Hes-1 in MCF-7 cells (P <0.01).In shNotch1 group,the number of apoptotic cells was much higher (P < 0.01) and mitochondrial membrane potential was much lower (P < 0.05) than those in shControl group.The protein levels of p-JNK1,p-p53,PUMA,NOXA and cleaved caspase-3 increased obviously after silencing of Notch1 was performed in MCF-7 cells (P < 0.05).CONCLUSION:Notch1 silencing induces apoptosis of

  9. Mutations in the p53 gene occur in diverse human tumour types.

    Science.gov (United States)

    Nigro, J M; Baker, S J; Preisinger, A C; Jessup, J M; Hostetter, R; Cleary, K; Bigner, S H; Davidson, N; Baylin, S; Devilee, P

    1989-12-01

    The p53 gene has been a constant source of fascination since its discovery nearly a decade ago. Originally considered to be an oncogene, several convergent lines of research have indicated that the wild-type gene product actually functions as a tumour suppressor gene. For example, expression of the neoplastic phenotype is inhibited, rather than promoted, when rat cells are transfected with the murine wild-type p53 gene together with mutant p53 genes and/or other oncogenes. Moreover, in human tumours, the short arm of chromosome 17 is often deleted. In colorectal cancers, the smallest common region of deletion is centred at 17p13.1; this region harbours the p53 gene, and in two tumours examined in detail, the remaining (non-deleted) p53 alleles were found to contain mutations. This result was provocative because allelic deletion coupled with mutation of the remaining allele is a theoretical hallmark of tumour-suppressor genes. In the present report, we have attempted to determine the generality of this observation; that is, whether tumours with allelic deletions of chromosome 17p contain mutant p53 genes in the allele that is retained. Our results suggest that (1) most tumours with such allelic deletions contain p53 point mutations resulting in amino-acid substitutions, (2) such mutations are not confined to tumours with allelic deletion, but also occur in at least some tumours that have retained both parental 17p alleles, and (3) p53 gene mutations are clustered in four 'hot-spots' which exactly coincide with the four most highly conserved regions of the gene. These results suggest that p53 mutations play a role in the development of many common human malignancies.

  10. Induction of p53-Specific Immunity by a p53 Synthetic Long Peptide Vaccine in Patients Treated for Metastatic Colorectal Cancer

    NARCIS (Netherlands)

    Speetjens, Frank M.; Kuppen, PeterJ. K.; Welters, Marij. J. P.; Essahsah, Farah; van den Brink, Anne Marie E. G. Voet; Lantrua, M. Graziella Kallenberg; Valentijn, A. Rob P. M.; Oostendorp, Jaap; Fathers, Lorraine M.; Nijman, Hans W.; Drijfhout, Jan W.; van de Velde, Cornelis J. H.; Melief, Cornelis J. M.; van der Burg, Sjoerd H.

    2009-01-01

    Purpose: The tumor-associated self-antigen p53 is commonly overexpressed in cancer, including colorectal cancer, and can serve as a target for immunotherapy. The safety and immunogenicity of a p53 synthetic long peptide (p53-SLP) vaccine were investigated in patients treated for metastatic colorecta

  11. Aberrant splicing of the DMP1-ARF-MDM2-p53 pathway in cancer.

    Science.gov (United States)

    Inoue, Kazushi; Fry, Elizabeth A

    2016-07-01

    Alternative splicing (AS) of mRNA precursors is a ubiquitous mechanism for generating numerous transcripts with different activities from one genomic locus in mammalian cells. The gene products from a single locus can thus have similar, dominant-negative or even opposing functions. Aberrant AS has been found in cancer to express proteins that promote cell growth, local invasion and metastasis. This review will focus on the aberrant splicing of tumor suppressor/oncogenes that belong to the DMP1-ARF-MDM2-p53 pathway. Our recent study shows that the DMP1 locus generates both tumor-suppressive DMP1α (p53-dependent) and oncogenic DMP1β (p53-independent) splice variants, and the DMP1β/α ratio increases with neoplastic transformation of breast epithelial cells. This process is associated with high DMP1β protein expression and shorter survival of breast cancer (BC) patients. Accumulating pieces of evidence show that ARF is frequently inactivated by aberrant splicing in human cancers, demonstrating its involvement in human malignancies. Splice variants from the MDM2 locus promote cell growth in culture and accelerate tumorigenesis in vivo. Human cancers expressing these splice variants are associated with advanced stage/metastasis, and thus have negative clinical impacts. Although they lack most of the p53-binding domain, their activities are mostly dependent on p53 since they bind to wild-type MDM2. The p53 locus produces splice isoforms that have either favorable (β/γ at the C-terminus) or negative impact (Δ40, Δ133 at the N-terminus) on patients' survival. As the oncogenic AS products from these loci are expressed only in cancer cells, they may eventually become targets for molecular therapies.

  12. Tumor suppressor p53 and its gain-of-function mutants in cancer

    OpenAIRE

    2013-01-01

    Tumor suppressor p53 plays a pivotal role in tumor suppression. p53 is the most frequently mutated gene in cancer. As a transcription factor, p53 mainly exerts its role in tumor suppression through transcriptional regulation of its downstream target genes. Thus, p53 and its target genes form a complex p53 signaling pathway to regulate a wide variety of biological processes to prevent tumorigenesis. Recent studies have revealed that in addition to apoptosis, cell cycle arrest and senescence, p...

  13. The Rho GTPase RhoE is a p53-regulated candidate tumor suppressor in cancer cells.

    Science.gov (United States)

    Zhu, Yajie; Zhou, Jitao; Xia, Hongwei; Chen, Xiangzheng; Qiu, Meng; Huang, Juan; Liu, Surui; Tang, Qiulin; Lang, Nan; Liu, Zhen; Liu, Ming; Zheng, Yi; Bi, Feng

    2014-03-01

    Previous studies have shown that RhoE, an atypical member of the Rho GTPase family, may play an opposite role to RhoA in regulating cell proliferation and invasion. To explore the relationship between RhoE and the malignant phenotypes of human cancer, we have determined the expression patterns of RhoE in varying grade of human cancer tissues and tested the effects of RhoE expression in several RhoE underexpressing cancer cell lines. Systemic immunocytochemistry analyses of gastric, colorectal, lung and breast carcinomas, respectively, showed that RhoE protein expression was significantly decreased in most cancer cases compared with that of adjacent normal tissues. Enhanced RhoE expression could markedly inhibit proliferation, migration and invasion and induce apoptosis of the cancer cells which have relatively low levels of endogenous RhoE expression. Wild-type p53 (wt-p53) could strongly increase RhoE expression in p53-transfected cells. Furthermore, the luciferase assays indicated that wt-p53 significantly enhanced the activities of RhoE promoter compared with mutant p53 (mt-p53) in PC3 cells (p53 null). Collectively, data are presented showing that RhoE may participate in human cancer progression and act as a candidate target of p53, and these findings also strongly suggest that RhoE may be a new candidate tumor suppressor and could serve as a potential target in the gene therapy of cancer.

  14. Distinct pattern of p53 mutations in bladder cancer

    DEFF Research Database (Denmark)

    Spruck, C H; Rideout, W M; Olumi, A F

    1993-01-01

    A distinct mutational spectrum for the p53 tumor suppressor gene in bladder carcinomas was established in patients with known exposures to cigarette smoke. Single-strand conformational polymorphism analysis of exons 5 through 8 of the p53 gene showed inactivating mutations in 16 of 40 (40%) bladder...

  15. p53 Superfamily proteins in marine bivalve cancer and stress biology.

    Science.gov (United States)

    Walker, Charles W; Van Beneden, Rebecca J; Muttray, Annette F; Böttger, S Anne; Kelley, Melissa L; Tucker, Abraham E; Thomas, W Kelley

    2011-01-01

    The human p53 tumour suppressor protein is inactivated in many cancers and is also a major player in apoptotic responses to cellular stress. The p53 protein and the two other members of this protein family (p63, p73) are encoded by distinct genes and their functions have been extensively documented for humans and some other vertebrates. The structure and relative expression levels for members of the p53 superfamily have also been reported for most major invertebrate taxa. The functions of homologous proteins have been investigated for only a few invertebrates (specifically, p53 in flies, nematodes and recently a sea anemone). These studies of classical model organisms all suggest that the gene family originally evolved to mediate apoptosis of damaged germ cells or to protect germ cells from genotoxic stress. Here, we have correlated data from a number of molluscan and other invertebrate sequencing projects to provide a framework for understanding p53 signalling pathways in marine bivalve cancer and stress biology. These data suggest that (a) the two identified p53 and p63/73-like proteins in soft shell clam (Mya arenaria), blue mussel (Mytilus edulis) and Northern European squid (Loligo forbesi) have identical core sequences and may be splice variants of a single gene, while some molluscs and most other invertebrates have two or more distinct genes expressing different p53 family members; (b) transcriptional activation domains (TADs) in bivalve p53 and p63/73-like protein sequences are 67-69% conserved with human p53, while those in ecdysozoan, cnidarian, placozoan and choanozoan eukaryotes are ≤33% conserved; (c) the Mdm2 binding site in the transcriptional activation domain is 100% conserved in all sequenced bivalve p53 proteins (e.g. Mya, Mytilus, Crassostrea and Spisula) but is not present in other non-deuterostome invertebrates; (d) an Mdm2 homologue has been cloned for Mytilus trossulus; (e) homologues for both human p53 upstream regulatory and

  16. Effect of Regulating Pokemon-p14ARF-p53 Pathway on Proliferation and Apoptosis of Human Colon Cancer Cells%调控Pokemon-p14ARF-p53通路对人结肠癌细胞增殖和凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    朱迎春; 徐凌; 王锋; 郭传勇; 柏乃运; 陈岳祥

    2013-01-01

    背景:研究发现转录抑制因子Pokemon是一种关键性致癌因子,在多种人类恶性肿瘤中表达异常上调,在体内、外实验中均能促进细胞的肿瘤性转化.Pokemon对抑癌基因ARF具有特异性转录抑制作用.目的:应用RNA干扰技术抑制人结肠癌细胞株HT-29的Pokemon表达,观察其表达抑制对肿瘤细胞增殖和凋亡的影响并探讨其可能的分子机制.方法:根据Pokemon cDNA序列设计干扰序列,构建重组干扰质粒,经脂质体介导转染入HT-29细胞.以real time RT-PCR和蛋白质印迹法检测Pokemon、p14ARF、p53表达,流式细胞术检测细胞周期和细胞凋亡.结果:Pokemon siRNA能有效抑制HT-29细胞中的Pokemon mRNA和蛋白表达,mRNA相对表达量为0.29 ±0.04,同时p14ARF、p53 mRNA和蛋白表达明显上调,mRNA相对表达量分别为3.03 ±0.49和2.80±0.25.与转染无效序列siRNA的HT-29细胞相比,Pokemon表达抑制的HT-29细胞G0/G1期细胞比例增加(43.6%±2.3%对34.7%±1.9%,P <0.05),细胞凋亡增多(10.7%±1.9%对2.7%±0.4%,P<0.05).结论:人结肠癌细胞中的Pokemon表达与p14ARF、p53表达之间存在负相关关系,抑制Pokemon可通过上调p14ARF-p53信号通路阻滞肿瘤细胞的细胞周期进程,并诱导细胞凋亡.调控Pokemon-p14ARF-p53信号通路有望作为结肠癌的治疗靶点.%Transcriptional repressor Pokemon was identified as a critical factor in oncogenesis. It is aberrantly overexpressed in many human cancers, and leads to overt oncogenic transformation in both in vitro and in vivo models. Pokemon can specifically repress the transcription of tumor suppressor gene ARF. Aims: To investigate the effect of inhibiting Pokemon by RNA interfering technique on proliferation and apoptosis of human colon cancer cell line HT-29 and its possible molecular mechanism. Methods: Interference sequence was designed according to the cDNA sequence of Pokemon for constructing the recombinant interference plasmid. HT

  17. REDOX IMAGING OF THE p53-DEPENDENT MITOCHONDRIAL REDOX STATE IN COLON CANCER EX VIVO

    Directory of Open Access Journals (Sweden)

    HE N. XU

    2013-07-01

    Full Text Available The mitochondrial redox state and its heterogeneity of colon cancer at tissue level have not been previously reported. Nor has how p53 regulates mitochondrial respiration been measured at (deep tissue level, presumably due to the unavailability of the technology that has sufficient spatial resolution and tissue penetration depth. Our prior work demonstrated that the mitochondrial redox state and its intratumor heterogeneity is associated with cancer aggressiveness in human melanoma and breast cancer in mouse models, with the more metastatic tumors exhibiting localized regions of more oxidized redox state. Using the Chance redox scanner with an in-plane spatial resolution of 200 μm, we imaged the mitochondrial redox state of the wild-type p53 colon tumors (HCT116 p53 wt and the p53-deleted colon tumors (HCT116 p53-/- by collecting the fluorescence signals of nicotinamide adenine dinucleotide (NADH and oxidized flavoproteins [Fp, including flavin adenine dinucleotide (FAD] from the mouse xenografts snap-frozen at low temperature. Our results show that: (1 both tumor lines have significant degree of intratumor heterogeneity of the redox state, typically exhibiting a distinct bi-modal distribution that either correlates with the spatial core–rim pattern or the "hot/cold" oxidation-reduction patches; (2 the p53-/- group is significantly more heterogeneous in the mitochondrial redox state and has a more oxidized tumor core compared to the p53 wt group when the tumor sizes of the two groups are matched; (3 the tumor size dependence of the redox indices (such as Fp and Fp redox ratio is significant in the p53-/- group with the larger ones being more oxidized and more heterogeneous in their redox state, particularly more oxidized in the tumor central regions; (4 the H&E staining images of tumor sections grossly correlate with the redox images. The present work is the first to reveal at the submillimeter scale the intratumor heterogeneity pattern of

  18. ErbB2 inhibition by lapatinib promotes degradation of mutant p53 protein in cancer cells.

    Science.gov (United States)

    Li, Dun; Marchenko, Natalia D

    2017-01-24

    Mutations in the p53 tumor suppressor gene are the most prevalent genetic events in human Her2-positive breast cancer and are associated with poor prognosis and survival. Human clinical data and our in vitro and in vivo studies strongly suggest potent oncogenic cooperation between mutant p53 and Her2 (ErbB2). Yet, the translational significance of mutant p53 in Her2 positive breast cancer, especially with respect to Her2-targeted therapies, has not been evaluated. Our previous work identified novel oncogenic activity of mutant p53 whereby mutp53 amplifies ErbB2 signaling via the mutp53-HSF1-ErbB2 feed-forward loop. Here we report that pharmacological interception of this circuit by ErbB2 inhibitor lapatinib downregulates mutant p53 in vitro and in vivo. We found that ErbB2 inhibition by lapatinib inhibits transcription factor HSF1, and its target Hsp90, followed by mutant p53 degradation in MDM2 dependent manner. Thus, our data suggest that mutant p53 sensitizes cancer cells to lapatinib via two complementary mechanisms: mutant p53 mediated amplification of ErbB2 signaling, and simultaneous annihilation of both potent oncogenic drivers, ErbB2 and mutant p53. Hence, our study could provide valuable information for the optimization of therapeutic protocols to achieve superior clinical effects in the treatment of Her2 positive breast cancer.

  19. Analysis of p53 and vascular endothelial growth factor expression in human gallbladder carcinoma for the determination of tumor vascularity

    Institute of Scientific and Technical Information of China (English)

    Yu Tian; Ren-Yu Ding; Ying-Hui Zhi; Ren-Xuan Guo; Shuo-Dong Wu

    2006-01-01

    AIM: To examine the expression of p53 and vascular endothelial growth factor (VEGF) as well as microvessel count (MVC) and to investigate the role of VEGF as an angiogenic marker and the possible role of p53 in the regulation of angiogenesis in human gallbladder carcinoma.METHODS: Surgically resected specimens of 49 gallbladder carcinomas were studied by immunohistochemical staining for p53 protein, VEGF, and factor Ⅷ-related antigen. VEGF expression and mutant p53 expression were then correlated with Nevin stage,differentiation grade, MVC, and lymph node metastasis.RESULTS: Positive p53 protein and VEGF expressions were found in 61.2% and 63.3% of tumors, respectively.p53 and VEGF staining status was identical in 55.1%of tumors. The Nevin staging of p53- or VEGF-positive tumors was significantly later than that of negative tumors. The MVC in p53- or VEGF-positive tumors was significantly higher than that in negative tumors,and MVC in both p53- and VEGF-negative tumors was significantly lower than that in the other subgroups.CONCLUSION: Our findings suggest that p53-VEGF pathway can regulate tumor angiogenesis in human gallbladder carcinoma. Combined analysis of p53 and VEGF expression might be useful for predicting the tumor vascularity of gallbladder cancer.

  20. Modeling Human Epithelial Ovarian Cancer in Mice by Alteration of Expression of the BRCA1 and/or p53 Genes

    Science.gov (United States)

    2008-02-01

    including high level chromosome damage, variable chromosome counts, rearrangements and multiclonal populations ( dicentrics , translocations...sarcoma arising in the p53LoxP/LoxP group, while not normal, generally had patterns of whole chromosome gains and losses consistent with aneuploidy and...many fewer regions of interstitial chromosomal gains/losses detected by aCGH as compared to tumors isolated from Brca1LoxP/LoxP;p53LoxP/LoxP mice

  1. Pleckstrin homology domain-containing protein PHLDB3 supports cancer growth via a negative feedback loop involving p53

    Science.gov (United States)

    Chao, Tengfei; Zhou, Xiang; Cao, Bo; Liao, Peng; Liu, Hongbing; Chen, Yun; Park, Hee-Won; Zeng, Shelya X.; Lu, Hua

    2016-01-01

    The tumour suppressor p53 transactivates the expression of its target genes to exert its functions. Here, we identify a pleckstrin homology domain-containing protein (PHLDB3)-encoding gene as a p53 target. PHLDB3 overexpression increases proliferation and restrains apoptosis of wild-type p53-harboring cancer cells by reducing p53 protein levels. PHLDB3 binds to MDM2 (mouse double minute 2 homolog) and facilitates MDM2-mediated ubiquitination and degradation of p53. Knockdown of PHLDB3 more efficiently inhibits the growth of mouse xenograft tumours derived from human colon cancer HCT116 cells that contain wild type p53 compared with p53-deficient HCT116 cells, and also sensitizes tumour cells to doxorubicin and 5-Fluorouracil. Analysis of cancer genomic databases reveals that PHLDB3 is amplified and/or highly expressed in numerous human cancers. Altogether, these results demonstrate that PHLDB3 promotes tumour growth by inactivating p53 in a negative feedback fashion and suggest PHLDB3 as a potential therapeutic target in various human cancers. PMID:28008906

  2. Significance of Ebp1 and p53 protein expression in cervical cancer.

    Science.gov (United States)

    Liu, L; Li, X D; Chen, H Y; Cui, J S; Xu, D Y

    2015-10-02

    In this study, the ErbB3-binding protein (Ebp1) and p53 protein expression in cervical cancer tissues, and its significance in the prognosis of the disease was investigated. Ebp1 and p53 protein expression was detected by immunohistochemical analysis in cervical cancer tissues (N = 60) and normal tissues adjacent to the cancer tissues (N = 60). The rates of positive Ebp1 and p53 protein expression were 35.0 and 60.0%, respectively. Ebp1 and p53 were overexpressed in cervical cancer tissues, compared to normal tissues (P p53 protein expression was not correlated with age, tumor size, or family tumor history (P > 0.05). However, high levels of expression of Ebp1 and p53 were positively correlated with the TNM stage and lymphatic metastasis in cervical cancer patients (P p53 expression levels in cervical cancer patients could support the effective prediction of metastatic potential and patient prognosis.

  3. Loss of LSD1 (lysine-specific demethylase 1) suppresses growth and alters gene expression of human colon cancer cells in a p53- and DNMT1(DNA methyltransferase 1)-independent manner.

    Science.gov (United States)

    Jin, Lihua; Hanigan, Christin L; Wu, Yu; Wang, Wei; Park, Ben Ho; Woster, Patrick M; Casero, Robert A

    2013-01-15

    Epigenetic silencing of gene expression is important in cancer. Aberrant DNA CpG island hypermethylation and histone modifications are involved in the aberrant silencing of tumour-suppressor genes. LSD1 (lysine-specific demethylase 1) is a H3K4 (histone H3 Lys4) demethylase associated with gene repression and is overexpressed in multiple cancer types. LSD1 has also been implicated in targeting p53 and DNMT1 (DNA methyltransferase 1), with data suggesting that the demethylating activity of LSD1 on these proteins is necessary for their stabilization. To examine the role of LSD1 we generated LSD1 heterozygous (LSD1+/-) and homozygous (LSD1-/-) knockouts in the human colorectal cancer cell line HCT116. The deletion of LSD1 led to a reduced cell proliferation both in vitro and in vivo. Surprisingly, the knockout of LSD1 in HCT116 cells did not result in global increases in its histone substrate H3K4me2 (dimethyl-H3K4) or changes in the stability or function of p53 or DNMT1. However, there was a significant difference in gene expression between cells containing LSD1 and those null for LSD1. The results of the present study suggested that LSD1 is critical in the regulation of cell proliferation, but also indicated that LSD1 is not an absolute requirement for the stabilization of either p53 or DNMT1.

  4. Activations of Both Extrinsic and Intrinsic Pathways in HCT 116 Human Colorectal Cancer Cells Contribute to Apoptosis through p53-Mediated ATM/Fas Signaling by Emilia sonchifolia Extract, a Folklore Medicinal Plant.

    Science.gov (United States)

    Lan, Yu-Hsuan; Chiang, Jo-Hua; Huang, Wen-Wen; Lu, Chi-Cheng; Chung, Jing-Gung; Wu, Tian-Shung; Jhan, Jia-Hua; Lin, Kuei-Li; Pai, Shu-Jen; Chiu, Yu-Jen; Tsuzuki, Minoru; Yang, Jai-Sing

    2012-01-01

    Emilia sonchifolia (L.) DC (Compositae), an herbaceous plant found in Taiwan and India, is used as folk medicine. The clinical applications include inflammation, rheumatism, cough, cuts fever, dysentery, analgesic, and antibacteria. The activities of Emilia sonchifolia extract (ESE) on colorectal cancer cell death have not been fully investigated. The purpose of this study explored the induction of apoptosis and its molecular mechanisms in ESE-treated HCT 116 human colorectal cancer cells in vitro. The methanolic ESE was characterized, and γ-humulene was formed as the major constituent (63.86%). ESE induced cell growth inhibition in a concentration- and time-dependent response by MTT assay. Apoptotic cells (DNA fragmentation, an apoptotic catachrestic) were found after ESE treatment by TUNEL assay and DNA gel electrophoresis. Alternatively, ESE stimulated the activities of caspase-3, -8, and -9 and their specific caspase inhibitors protected against ESE-induced cytotoxicity. ESE promoted the mitochondria-dependent and death-receptor-associated protein levels. Also, ESE increased ROS production and upregulated the levels of ATM, p53, and Fas in HCT 116 cells. Strikingly, p53 siRNA reversed ESE-reduced viability involved in p53-mediated ATM/Fas signaling in HCT 116 cells. In summary, our result is the first report suggesting that ESE may be potentially efficacious in the treatment of colorectal cancer.

  5. The p53 pathway in hematopoiesis: lessons from mouse models, implications for humans

    OpenAIRE

    Pant, Vinod; Quintás-Cardama, Alfonso; Lozano, Guillermina

    2012-01-01

    Aberrations in the p53 tumor suppressor pathway are associated with hematologic malignancies. p53-dependent cell cycle control, senescence, and apoptosis functions are actively involved in maintaining hematopoietic homeostasis under normal and stress conditions. Whereas loss of p53 function promotes leukemia and lymphoma development in humans and mice, increased p53 activity inhibits hematopoietic stem cell function and results in myelodysplasia. Thus, exquisite regulation of p53 activity is ...

  6. RAS AND p53 EXPRESSION IN HUMAN THYROID CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To investigate the possible interaction between the ras and p53 genes over-expression in thyroid carcinoma, and whether there is a correlation between the ras and p53 over-expression and clinicopathological criteria. Methods: Eighty patients with thyroid lesions were examined for expression of ras and p53 genes by the labeled streptavidin biotin peroxidase (LSAB) method. Of these patients, 54 were diagnosed (average age: 39.9± 15.9 years) with malignant lesions. Of those included in the study, 31 has papillary carcinoma, 13 had follicular carcinoma, 7 had medullary carcinoma, 3 had undifferentiated carcinoma and 19 were stratified to stage I, 28 to stage II, 2 to stage III and 5 to stage IV according to TNM staging system. Twenty-six benign nodular thyroid disorders were studied as control. Results: Positive immunostain results for ras and p53 genes were statistically significant between thyroid carcinomas and benign disorders (90.7% vs 23%, 55.5% vs 30.7%, P<0.05). Both p53 and ras overexpressions coexisted in 30 thyroid carcinomas, and of these, 3 died and 5 had recurrences within 4 years. Conclusions: Activation of ras gene and inactivation of p53 gene were cooperatively associated in thyroid tumorigenesis. The concurrent overexpressions of ras and p53 could result in a poor prognosis.

  7. Expression of p53 family genes in urinary bladder cancer: correlation with disease aggressiveness and recurrence.

    Science.gov (United States)

    Papadogianni, Danae; Soulitzis, Nikolaos; Delakas, Demetrios; Spandidos, Demetrios A

    2014-03-01

    p53 is a tumour suppressor gene with an established role in the majority of human neoplasias. Its homologues-p63 and p73-cannot be classified as tumour suppressors, since they encode isoforms with oncogenic properties as well. p63 plays a crucial role in epithelial cell differentiation and p73 is essential for neuronal cell development. The p63 and p73 expressions have been investigated in a variety of human tumours including bladder carcinomas; yet, this is the first study to simultaneously analyse the transcriptional levels of all p53 family members in bladder cancer. Using quantitative real-time polymerase chain reaction, we measured the mRNA expression of p53, p63 and p73 in 30 bladder tumours, each paired with adjacent normal tissue. All three studied genes were up-regulated in malignant specimens, p53 by 1.9-fold, p63 by threefold and p73 by twofold, respectively. Further analysis suggested that p63 and p73 act independently of p53 in the malignant bladder epithelium. Statistical analysis revealed that p63 overexpression was more frequent in recurrent bladder tumours (p = 0.045) and in older patients (p = 0.022). Papillary tumours also exhibited abnormal p63 expression (p = 0.026). Finally, p73 was up-regulated in Grade III one-site tumours (p = 0.040). Our results indicate that all p53 family members are abnormally expressed in bladder cancer but do not act synergistically. High levels of p63 correlate with non-muscle invasive tumours with frequent relapses, whereas p73 overexpression is associated with a more aggressive tumour phenotype.

  8. Hypermethylation of the 5′ CpG island of the p14ARF flanking exon 1β in human colorectal cancer displaying a restricted pattern of p53 overexpression concomitant with increased MDM2 expression

    Directory of Open Access Journals (Sweden)

    Nyiraneza Christine

    2012-06-01

    Full Text Available Abstract Background It has been suggested that inactivation of p14ARF, a tumor suppressor central to regulating p53 protein stability through interaction with the MDM2 oncoprotein, abrogates p53 activity in human tumors retaining the wild-type TP53 gene. Differences in expression of tumor suppressor genes are frequently associated with cancer. We previously reported on a pattern of restricted p53 immunohistochemical overexpression significantly associated with microsatellite instability (MSI, low TP53 mutation frequency, and MDM2 overexpression in colorectal cancers (CRCs. In this study, we investigated whether p14ARF alterations could be a mechanism for disabling the p53 pathway in this subgroup of CRCs. Results Detailed maps of the alterations in the p14ARF gene were determined in a cohort of 98 CRCs to detect both nucleotide and copy-number changes. Methylation-specific PCR combined with bisulfite sequencing was used to evaluate the prevalence and distribution of p14ARF methylation. p14ARF alterations were then correlated with MSI status, TP53 mutations, and immunohistochemical expression of p53 and MDM2. The frequency of p14ARF mutations was extremely low (1/98; 1%, whereas coexistence of methylated and unmethylated alleles in both tumors and normal colon mucosa was common (91/98; 93%. Only seven of ninety-eight tumors (7% had a distinct pattern of methylation compared with normal colon mucosa. Evaluation of the prevalence and distribution of p14ARF promoter methylation in a region containing 27 CpG sites in 35 patients showed a range of methylated CpG sites in tumors (0 to 25 (95% CI 1 to 13 versus 0 to 17 (95% CI 0 to 2 in adjacent colon mucosa (P = 0.004. Hypermethylation of the p14ARF promoter was significantly correlated with the restricted p53 overexpression pattern (P = 0.03, and MDM2 overexpression (P = 0.02, independently of MSI phenotype. Although no significant correlation between p14ARF methylation and TP53 mutational

  9. 低频超声联合微泡促进脂质体介导的人前列腺癌细胞野生型 P53基因转染的实验研究%Low frequency ultrasound combined with microbubbles to promote the transfection of wild-type P53 gene in human prostate cancer cells mediated by liposome

    Institute of Scientific and Technical Information of China (English)

    白文坤; 张蔚; 胡兵

    2015-01-01

    目的:研究低频超声联合微泡在促进脂质体介导的人前列腺癌细胞野生型 P53基因转染中的作用。方法选用频率为21 kHz,功率为46 mW/cm2的低频超声,占空比2∶8(开2 s,停8 s),辐照人前列腺癌 PC-3细胞5 min。PC-3细胞制成细胞悬液,调整细胞浓度为1×105个/ml,细胞分为8组:对照组、单独微泡组、单独超声组、超声联合微泡组、单独脂质体组、脂质体联合微泡组、脂质体联合超声组、脂质体联合超声及微泡组。每微泡组加入常规配置的声诺维200μl,每组均加入野生型 P53质粒,质粒与脂质体比为1∶2。辐照后继续培养24 h,荧光定量及 western-blot 检测基因转染效率,CCK-8检测细胞 OD值,计算细胞存活率,流式细胞仪检测细胞凋亡。结果转染后脂质体联合超声及微泡组较单独脂质体组及对照组能够明显提高人野生型 P53基因及蛋白的表达,差异均有统计学意义(P <0.001)。转染后脂质体联合超声及微泡组较单独脂质体组及对照组明显提高人前列腺癌 PC-3细胞凋亡率,差异均有统计学意义(P <0.001),并且转染后脂质体联合超声、微泡组较单独脂质体组及对照组细胞存活明显受抑制,差异均有统计学意义(P <0.001)。结论低频低能量超声联合微泡能够促进脂质体介导的人野生型 P53基因的转染。%Objective To study low frequency ultrasound combined with microbubbles to promote the transfection of P53 gene in human prostate cancer cells mediated by liposome.Methods Ultrasound equipment was used with a frequency of 21 kHz and intensity was 46 mW/cm2 and the working time was controlled at 20% (i.e.,2 s “on”time and 8 s “off”time)lasting 5 minutes.The human prostate cancer cell line PC-3 suspension was prepared,the cell concentration was adjusted to 1 × 10 5 cell/ ml,and cells were divided into 8 groups:control group,single microbubbles group,single ultrasound group

  10. Ling Zhi-8 mediates p53-dependent growth arrest of lung cancer cells proliferation via the ribosomal protein S7-MDM2-p53 pathway.

    Science.gov (United States)

    Wu, Chien-Ting; Lin, Tung-Yi; Hsu, Hsien-Yeh; Sheu, Fuu; Ho, Chau-Mei; Chen, Edmund I-T

    2011-12-01

    Ling Zhi-8 (LZ-8), an immunomodulatory protein, is derived from and has been cloned from the medicinal mushroom Ganoderma lucidum (Reishi or Ling Zhi); this protein exhibits immunomodulating and antitumor properties. We investigated the effects of recombinant LZ-8 protein (rLZ-8) on the proliferation of A549 human lung cancer cells. Here, we showed that rLZ-8 inhibits cell growth and that this is correlated with increased G(1) arrest. The treatment of A549 cells with rLZ-8 activated p53 and p21 expression, and both the G(1) arrest and the antigrowth effect were found to be p53 dependent. It was further demonstrated that rLZ-8 inhibited tumor growth in mice transplanted with Lewis lung carcinoma cells. Interestingly, rLZ-8 treatment was found to lead to nucleolar stress (or ribosomal stress) as evidenced by inhibition of precursor ribosomal RNA synthesis and reduced polysome formation in A549 cells. These changes resulted in an increasing binding of ribosomal protein S7 to MDM2 and a decreased interaction between MDM2 and p53. Taking these results together, we have identified a novel rLZ-8 antitumor function that positively modulates p53 via ribosomal stress and inhibits lung cancer cell growth in vitro and in vivo. Our current results suggest that rLZ-8 may have potential as a therapeutic intervention for the treatment of cancers that contain wild-type p53 and high expression of MDM2.

  11. Overexpression of p53 mRNA in colorectal cancer and its relationship to p53 gene mutation.

    OpenAIRE

    el-Mahdani, N.; Vaillant, J. C.; Guiguet, M; PRÉVOT, S.; Bertrand, V.; Bernard, C.; Parc, R.; Béréziat, G.; Hermelin, B

    1997-01-01

    We analysed the frequency of p53 mRNA overexpression in a series of 109 primary colorectal carcinomas and its association with p53 gene mutation, which has been correlated with short survival. Sixty-nine of the 109 cases (63%) demonstrated p53 mRNA overexpression, without any correlation with stage or site of disease. Comparison with p53 gene mutation indicated that, besides cases in which p53 gene mutation and p53 mRNA overexpression were either both present (40 cases) or both absent (36 cas...

  12. p53R2 overexpression in cervical cancer promotes AKT signaling and EMT, and is correlated with tumor progression, metastasis and poor prognosis.

    Science.gov (United States)

    Jiang, Chao; Xu, Rui; Li, Xiao-Xing; Wang, Yan-Yan; Liang, Wen-Qian; Zeng, Ju-Deng; Zhang, Shan-Shan; Xu, Xiao-Yi; Yang, Yang; Zhang, Mei-Yin; Wang, Hui-Yun; Zheng, X F Steven

    2017-08-25

    p53R2 is a p53-inducible ribonucleotide reductase subunit involved in deoxyribonucleotide biosynthesis and DNA repair. Although p53R2 has been linked to human cancer, its role in cervical cancer remains unknown. In this study, we investigated the expression and clinical significance of p53R2 in early-stage cervical cancer. p53R2 expression is significantly upregulated at both mRNA and protein levels in cervical cancer cells and tissues, compared with that in matched normal cervical cells and tissues, respectively. p53R2 overexpression is associated with increased risk of pelvic lymph node metastasis (PLNM, p = 0.001) and cancer relapse (p = 0.009). Patients with high p53R2 expression have a shorter overall survival (OS) and disease-free survival (DFS). p53R2 is an independent factor for predicting OS and DFS of cervical cancer patients. We further show that p53R2 is important for oncogenic growth, migration and invasion in cervical cancer cells. Mechanistically, p53R2 promotes Akt signaling and epithelial-mesenchymal transition (EMT). In conclusion, our study demonstrates for the first time that p53R2 protein is overexpressed in early-stage cervical cancer and unravels some unconventional oncogenic functions of p53R2. p53R2 may be a useful prognostic biomarker and therapeutic target for cervical cancer.

  13. Treating cancer when pRb and p53 cannot be reactivated.

    Science.gov (United States)

    Zhu, Liang

    2015-01-01

    Activation of oncoproteins and inactivation of tumor suppressors induces tumorigenesis. When these events happen upstream of pRb and p53, cancer therapies may initially succeed and then fail when pRb and p53 are activated and then re-inactivated. Therapies might succeed if they remain effective when pRb and p53 are genetically inactivated.

  14. Long Noncoding RNA PURPL Suppresses Basal p53 Levels and Promotes Tumorigenicity in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Xiao Ling Li

    2017-09-01

    Full Text Available Basal p53 levels are tightly suppressed under normal conditions. Disrupting this regulation results in elevated p53 levels to induce cell cycle arrest, apoptosis, and tumor suppression. Here, we report the suppression of basal p53 levels by a nuclear, p53-regulated long noncoding RNA that we termed PURPL (p53 upregulated regulator of p53 levels. Targeted depletion of PURPL in colorectal cancer cells results in elevated basal p53 levels and induces growth defects in cell culture and in mouse xenografts. PURPL associates with MYBBP1A, a protein that binds to and stabilizes p53, and inhibits the formation of the p53-MYBBP1A complex. In the absence of PURPL, MYBBP1A interacts with and stabilizes p53. Silencing MYBBP1A significantly rescues basal p53 levels and proliferation in PURPL-deficient cells, suggesting that MYBBP1A mediates the effect of PURPL in regulating p53. These results reveal a p53-PURPL auto-regulatory feedback loop and demonstrate a role for PURPL in maintaining basal p53 levels.

  15. Discrimination of p53 immunohistochemistry-positive tumors by its staining pattern in gastric cancer

    OpenAIRE

    2014-01-01

    Immunohistochemistry staining of p53 is a cheap and simple method to detect aberrant function of p53. However, there are some discrepancies between the result of immunohistochemistry staining and mutation analysis. This study attempted to find a new definition of p53 staining by its staining pattern. Immunohistochemistry staining of p53 and TP53 gene mutation analysis were performed in 148 gastric cancer patients. Also SNP-CGH array analysis was conducted to four cases. Positive staining of p...

  16. p53 Mutations and Protein Overexpression in Primary Colorectal Cancer and its Liver Metastasis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To compare p53 status in primary and hepatic metastatic colorectal cancer in 34 patients. Methods: p53 gene status (exons 5- 9) was examined by PCR, denaturing gradient gel electrophoresis (DGGE) and automated sequencing. P53 protein was detected by immunohistochemistry using monoclonal antibody DO-7. Results: p53 mutations were found in exons 5 through 9 in 21 of 34 patients (61.8%). Among them, 5 patients had mutation in liver metastasis but not in their primary tumors while in the other patients the same mutations were found in both primary and metastatic colorectal cancers. In no patients was p53 mutation exclusively found in the primary colorectal tumors. Moreover, additional mutation was detected in the metastatic lesions in two cases. Of the 37 mutations within the exons examined, 73% was missense mutation and 16% was nonsense mutation. There were 4 microinsertions. P53 protein was overexpressed in both primary and metastatic colorectal cancers with p53 gene mutations. The presence of p53 mutation significantly correlated with p53 protein accumulation (r=0.96, p< 0.001). However, in 4 patients with p53 nonsense mutation, immunohistochemical staining was negative. In three patients who showed no p53 mutation of the primary tumor, p53 protein was consistently overexpressed. Conclusion: In colorectal cancers, p53 gene mutation usually appears first in the primary tumor and maintains as such but is more prominent when metastasized to the liver. However, p53 gene mutation may occur only after being metastasized.Although p53 gene mutation and p53 protein overexpression correlate with each other, either parameter examined alone may lead to false positive or negative results.

  17. JNK2 downregulation promotes tumorigenesis and chemoresistance by decreasing p53 stability in bladder cancer

    Science.gov (United States)

    Zhao, Yu; Qian, Chenchen; Wang, Liguo; Qi, Jun

    2016-01-01

    Bladder cancer is one of the most common malignancies of the urinary system, and the 5-year survival rate remains low. A comprehensive understanding of the carcinogenesis and progression of bladder cancer is urgently needed to advance treatment. c-Jun N-terminal kinase-2 (JNK2) exhibits both tumor promoter and tumor suppressor actions, depending on tumor type. Here, we analyzed the JNK2 function in bladder cancer. Using gene expression microarrays, we demonstrated that JNK2 mRNA is downregulated in an orthotopic rat model of bladder cancer. JNK2 protein levels were lower in rat and human bladder cancer tissues than in normal tissues, and the levels correlated with those of p53. Moreover, JNK2 phosphorylated p53 at Thr-81, thus protecting p53 from MDM2-induced proteasome degradation. Decreased expression of JNK2 in T24 cells conferred resistance to cell death induced by mitomycin C. Furthermore, lower JNK2 expression was associated with poorer overall survival among patients who underwent radical cystectomy. These results indicate that JNK2 acts as a tumor suppressor in bladder cancer, and that decreased JNK2 expression promotes bladder cancer tumorigenesis. PMID:27147566

  18. Clinical implications of cytosine deletion of exon 5 of P53 gene in non small cell lung cancer patients

    Directory of Open Access Journals (Sweden)

    Rashid Mir

    2016-01-01

    Full Text Available Aim: Lung cancer is considered to be the most common cancer in the world. In humans, about 50% or more cancers have a mutated tumor suppressor p53 gene thereby resulting in accumulation of p53 protein and losing its function to activate the target genes that regulate the cell cycle and apoptosis. Extensive research conducted in murine cancer models with activated p53, loss of p53, or p53 missense mutations have facilitated researchers to understand the role of this key protein. Our study was aimed to evaluate the frequency of cytosine deletion in nonsmall cell lung cancer (NSCLC patients. Methods: One hundred NSCLC patients were genotyped for P53 (exon5, codon168 cytosine deletion leading to loss of its function and activate the target genes by allele-specific polymerase chain reaction. The P53 cytosine deletion was correlated with all the clinicopathological parameters of the patients. Results and Analysis: 59% cases were carrying P53 cytosine deletion. Similarly, the significantly higher incidence of cytosine deletion was reported in current smokers (75% in comparison to exsmoker and nonsmoker. Significantly higher frequency of cytosine deletion was reported in adenocarcinoma (68.08% than squamous cell carcinoma (52.83%. Also, a significant difference was reported between p53 cytosine deletion and metastasis (64.28%. Further, the majority of the cases assessed for response carrying P53 cytosine deletion were found to show faster disease progression. Conclusion: The data suggests that there is a significant association of the P53 exon 5 deletion of cytosine in codon 168 with metastasis and staging of the disease.

  19. The herbal medicine Melissa officinalis extract effects on gene expression of p53, Bcl-2, Her2, VEGF-A and hTERT in human lung, breast and prostate cancer cell lines.

    Science.gov (United States)

    Jahanban-Esfahlan, Rana; Seidi, Khaled; Monfaredan, Amir; Shafie-Irannejad, Vahid; Abbasi, Mehran Mesgari; Karimian, Ansar; Yousefi, Bahman

    2017-05-20

    Earlier, we verified that Melissa officinalis extract (MOE) elicits potent antiproliferative effects on different human cancer cells. To gain insights into the molecular mechanisms accounting for the cytotoxic effects of MOE, we assessed the expression patterns of several prominent molecules with therapeutic potential in cancer by Quantitative PCR (Q-PCR). A549, MCF-7 and PC3 cancer cells were grown in complete RPMI 1640 and seeded in 24 well micro plates. After incubation for 72h, 100μg/ml of MOE was added and the cells were further incubated for 72h. Afterwards, the cells were subjected to RNA extraction for the means of Q-PCR. Our results indicated that in PC3 cancer cells, MOE resulted in a significant downregulation of VEGF-A (0.0004 fold), Bcl-2 (0.001 fold), Her2 (0.02 fold), and hTERT (0.023 fold) compared to the untreated control. In addition, VEGF-A and hTERT mRNA were significantly downregulated in MCF-7 and A549 cancer cells, as well. Notably, high anti-angiogenic activity was closely associated with a high anti-telomerase activity of MOE in studying cancer cells. The decrease in VEGF-A expression was significantly superior than that of hTERT downregulation, as PC3 cancer cells with the highest hTERT down regulation (0.023) presented the highest anti VEGF activity (0.0004 fold), whereas MCF-7 cells with the lowest hTERT inhibition (0.213) showed the lowest VEGF inhibition(0.0435) among the three studied cancer cells. We noticed that the modulation of VEGF-A and hTERT gene expression can be considered as a common target, accounting for the therapeutic potential of MOE on human breast, lung and prostate cancer cells. Altogether, it is suggested that the potent antiproliferative activity of the hydroalcoholic extract of Melissa officinalis is somehow explainable by its high potency to inhibit expression of the prominent oncogenes Bcl2, Her2, VEGF-A and hTERT in prostate cancer. In tumors with functional p53, including MCF-7 and A549 cancer cells, the role

  20. Super p53 for Treatment of Ovarian Cancer

    Science.gov (United States)

    2016-07-01

    Headquarters Services , Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202...therapy, carboplatin, paclitaxel, polymeric drug delivery , polymer-adenovirus hybrid 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...modified p53, tumor suppressor, high grade serous carcinoma, combination therapy, carboplatin, paclitaxel, polymeric drug delivery , polymer

  1. Expression and significance of P53 protein and MDM-2 protein in human gliomas

    Institute of Scientific and Technical Information of China (English)

    WANG An-liu; LIU Zhao-xia; LI Guang; ZHANG Li-wei

    2011-01-01

    Background P53 is one of the most studied tumor suppressors in the cancer research, and over 50% of human tumors carry P53 mutations. MDM-2 is amplified and/or overexpressed in a variety of human tumors of diverse tissue origin. The aim of this study was to examine the expression of P53 protein and MDM-2 protein in gliomas, and to investigate the relationship between the expression of the two proteins and the histopathological grades of glioma. The relationship between MDM-2 protein expression and P53 protein expression was also analyzed.Methods The expression of P53 protein and MDM-2 protein was immunohistochemically detected using monoclonal antibodies in 242 paraffin embedded tissues, including 30 normal brain tissues from patients with craniocerebral injury and 212 tissues from patients with primary glioma (grade Ⅰ-Ⅱ group: 5 cases of grade Ⅰ, 119 cases of grade Ⅱ; and grade Ⅲ-Ⅳ group: 53 cases of grade Ⅲ, and 35 cases of grade Ⅳ).Results The P53 positive rate was significantly higher in the glioma groups than in the control group (P <0.0001). The P53 positive rate was significantly higher in glioma tissues of grade Ⅲ-V than in glioma tissues of grade Ⅰ-Ⅱ group (P=0.001). The MDM-2 positive rate was significantly higher in glioma groups than in the control group (P <0.0001).There was no significant difference in the MDM-2 positive rate between the two glioma groups (P=0.936). The expression of P53 protein was not related to expression of MDM-2 protein (P=0.069)Conclusions Overexpression of P53 protein might be related to the occurrence and progression of glioma.Overexpression of MDM-2 protein may play an important role in glioma tumorigenesis, but may not be involved in glioma progression. The overexpression of MDM-2 protein was an early event in malignant transformation of glioma. MDM-2 may be a key player in glioma in its own right.

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

    Science.gov (United States)

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

    2015-12-22

    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.

  3. Synthetic Bichalcone TSWU-BR23 Induces Apoptosis of Human Colon Cancer HT-29 Cells by p53-Mediated Mitochondrial Oligomerization of BAX/BAK and Lipid Raft Localization of CD95/FADD.

    Science.gov (United States)

    Lin, Meng-Liang; Chen, Shih-Shun; Wu, Tian-Shung

    2015-10-01

    A synthetic bichalcone analog, (E)-1-(3-((4-(4-acetylphenyl)piperazin-1-yl)methyl)-4-hydroxy-5-methoxyphenyl)-3-(pyridin-3-yl)prop-2-en-1-one (TSWU-BR23), has been shown to induce apoptosis in human colon cancer HT-29 cells involving the induction of CD95 and FAS-associated protein death domain (FADD), but its precise mechanism of action has not been fully elucidated. Using cell-surface biotinylation and sucrose density-gradient-based membrane flotation techniques, we showed that the disruption of TSWU-BR23-induced lipid raft localization of CD95/FADD by cholesterol-depleting agent (methyl-β-cyclodextrin) was reversed by cholesterol replenishment. Blockade of p53 expression by short-hairpin RNA (shRNA) suppressed oligomeric Bcl-2-associated x protein (BAX)/Bcl-2 antagonist killer 1 (BAK)-mediated mitochondrial apoptosis but did not inhibit lipid raft localization of CD95/FADD and pro-caspase-8 cleavage induced by TSWU-BR23. Co-expression of p53 shRNA and dominant-negative mutant of FADD completely inhibited TSWU-BR32-induced mitochondrial apoptotic cell death. Collectively, these data demonstrate that TSWU-BR23 leads to HT-29 cell apoptosis by inducing p53-mediated mitochondrial oligomerization of BAX/BAK and the localization of CD95/FADD with lipid rafts at the cell surface.

  4. 14-3-3 Sigma And p53 Expression in Gastric Cancer and Its Clinical Applications

    Directory of Open Access Journals (Sweden)

    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.

  5. Co-mutation of p53, K-ras genes and accumulation of p53 protein and its correlation to clinicopathological features in rectal cancer

    Institute of Scientific and Technical Information of China (English)

    Zhi-Zhong Pan; De-Sen Wan; Gong Chen; Li-Ren Li; Zhen-Hai Lu; Bi-Jun Huang

    2004-01-01

    AIM: To determine the accuracy of p53 gene mutations predicted by overexpression of p53 protein immunohistochemically,and to investigate the co-mutation of p53 and K-rasgenes in rectal cancer and its effect on promoting malignant biologic behaviors of tumors.METHODS: Ninety-seven specimens of rectal cancer were surgically resected in our hospital from August 1996 to October 1997. The hot mutation areas of p53 gene (in exons 5-8) and K-ras gene (in codon 5/12 and 13) were detected with polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), and overexpression of p53 protein was detected with immunohistochemistry (IHC) in the 97 specimens of rectal cancer. Correlation between gene mutations and tumor clinicopathologic factors was studied, and survival analysis was penfomed as well.RESULTS: There were 36 cases of p53 gene mutations in 61 p53 protein positive cases, and 21 cases of p53 gene non-mutation in 36 p53 protein negative cases respectively.The coincidence rate of p53 gene mutation by IHC method with PCR-SSCP method was 58.8% (57/97). The mutation rate of p53 gene was 52.6% (51/97), while K-ras gene mutation was observed in codons 12 and 13 in 61 cases with a mutation rate of 62.9% (61/97). Single gene mutation of p53 or K-raswas found in 32 cases. Both p53 and K-ras gene mutation were found in 48 cases. Statistical analysis showed that p53 and K-rasgene mutations were not related to the clinicopathologic factors, including tumor size, gross tumor type, histological classification, differentiation, invasion to intestinal veins, lymphatics and nerves, invasive depth to wall, lymph node metastasis, and Dukes' stages (P>0.05).The survival in patients with no gene mutation, single gene mutation and both gene mutations were similar (P>0.05).CONCLUSION: IHC has a certain false positive and false negative rate in detecting p53 gene mutations. Malignant biological behaviours of rectal cancer are not enhanced by p53 and K-rasgene mutations. Co

  6. Distinct Rayleigh scattering from hot spot mutant p53 proteins reveals cancer cells.

    Science.gov (United States)

    Jun, Ho Joon; Nguyen, Anh H; Kim, Yeul Hong; Park, Kyong Hwa; Kim, Doyoun; Kim, Kyeong Kyu; Sim, Sang Jun

    2014-07-23

    The scattering of light redirects and resonances when an electromagnetic wave interacts with electrons orbits in the hot spot core protein and oscillated electron of the gold nanoparticles (AuNP). This report demonstrates convincingly that resonant Rayleigh scattering generated from hot spot mutant p53 proteins is correspondence to cancer cells. Hot spot mutants have unique local electron density changes that affect specificity of DNA binding affinity compared with wild types. Rayleigh scattering changes introduced by hot-spot mutations were monitored by localized surface plasmon resonance (LSPR) shift changes. The LSPR λmax shift for hot-spot mutants ranged from 1.7 to 4.2 nm for mouse samples and from 0.64 nm to 2.66 nm for human samples, compared to 9.6 nm and 15 nm for wild type and mouse and human proteins, respectively with a detection sensitivity of p53 concentration at 17.9 nM. It is interesting that hot-spot mutants, which affect only interaction with DNA, launches affinitive changes as considerable as wild types. These changes propose that hot-spot mutants p53 proteins can be easily detected by local electron density alterations that disturbs the specificity of DNA binding of p53 core domain on the surface of the DNA probed-nanoplasmonic sensor.

  7. Effects of prostaglandin E2 on p53 mRNA transcription and p53 mutagenesis during T-cell-independent human B-cell clonal expansion

    Science.gov (United States)

    Haque, Shabirul; Yan, Xiao Jie; Rosen, Lisa; McCormick, Steven; Chiorazzi, Nicholas; Mongini, Patricia K. A.

    2014-01-01

    Within T-cell-dependent germinal centers, p53 gene transcription is repressed by Bcl-6 and is thus less vulnerable to mutation. Malignant lymphomas within inflamed extranodal sites exhibit a relatively high incidence of p53 mutations. The latter might originate from normal B-cell clones manifesting activation-induced cytosine deaminase (AID) and up-regulated p53 following T-cell-independent (TI) stimulation. We here examine p53 gene transcription in such TI clones, with a focus on modulatory effects of prostaglandin E2 (PGE2), and evaluate progeny for p53 mutations. Resting IgM+IgD+CD27− B cells from human tonsils were labeled with CFSE and stimulated in vitro with complement-coated antigen surrogate, IL-4, and BAFF ± exogenous PGE2 (50 nM) or an analog specific for the EP2 PGE2 receptor. We use flow cytometry to measure p53 and AID protein within variably divided blasts, qRT-PCR of p53 mRNA from cultures with or without actinomycin D to monitor mRNA transcription/stability, and single-cell p53 RT-PCR/sequencing to assess progeny for p53 mutations. We report that EP2 signaling triggers increased p53 gene transcriptional activity in AID+ cycling blasts (P<0.01). Progeny exhibit p53 mutations at a frequency (8.5×10−4) greater than the baseline error rate (<0.8×10−4). We conclude that, devoid of the repressive influences of Bcl-6, dividing B lymphoblasts in inflamed tissues should display heightened p53 transcription and increased risk of p53 mutagenesis.—Haque, S., Yan, X. J., Rosen, L., McCormick, S., Chiorazzi, N., Mongini, P. K. A. Effects of prostaglandin E2 on p53 mRNA transcription and p53 mutagenesis during T-cell-independent human B-cell clonal expansion. PMID:24145719

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. The effect of recombinant adenovirus p53 transfection on proliferation and apoptosis of gastric cancer cells with different types of p53%重组人p53腺病毒感染对携带不同p53状态胃癌细胞增殖和凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    刘明月; 王晚萍; 周云

    2012-01-01

    目的 研究重组人p53腺病毒感染不同p53状态胃癌细胞对其p53蛋白表达、生长抑制率、细胞周期与凋亡率的影响.方法 不同浓度重组人p53腺病毒感染3种不同p53状态胃癌细胞,即含野生型p53基因的细胞(wild-type)、含突变型p53基因的细胞(mutant-type)、含空载质粒即p53基因缺失的细胞(vector-cell).48 h后,用Western blotting法检测p53蛋白在3种胃癌细胞中的表达;用MTT法测定重组人p53腺病毒感染3种胃癌细胞的生长抑制率,用流式细胞仪检测细胞周期分布和凋亡率.结果rAd-p53感染3种胃癌细胞48 h后p53蛋白表达阳性,对照组p53基因缺失的胃癌细胞无表达,对照组含野生型p53基因的细胞和含突变型p53基因的细胞弱表达.rAd-p53对3种胃癌细胞的生长抑制效应在一定的浓度范围内呈剂量依赖性,而与细胞内在的p53状态无关.含野生型p53基因的细胞、含突变型p53基因的细胞和p53基因缺失的细胞感染rAd-p53后诱导G2/M期阻滞与细胞凋亡率分别增加2.5、3.6、3.2倍.结论 腺病毒介导p53基因感染3种不同p53状态胃癌细胞改变细胞内在的p53状态,p53蛋白表达、生长抑制率、细胞周期分布、凋亡率均与细胞内在的p53状态无关.%Objective To Study the effect of recombinant adenovirus p53 transfection on protein expression, growth inhibition rate,cell cycles and apotosis rate cells with different types of p53. Methods the recombinant adenovivus p53 in different and apotosis concentrations were infected. BGC-823 with three different p53 status; BGC-823 cells with wild-type p53 gene, BGC-823 cells with mutant type p53 gene and BGC-823 cells with p53 gene deletion were transfect-ed with recombinant human p53 adenovirus. After 48 h, the expression of p53 protein in three gastric cancer cell lines was detected by Western blotting method; cell proliferation was determined by MTT, cell-cycle distributions and apoptosis rates were detected

  10. p53 inhibits autophagy by interacting with the human ortholog of yeast Atg17, RB1CC1/FIP200.

    Science.gov (United States)

    Morselli, Eugenia; Shen, Shensi; Ruckenstuhl, Christoph; Bauer, Maria Anna; Mariño, Guillermo; Galluzzi, Lorenzo; Criollo, Alfredo; Michaud, Mickael; Maiuri, Maria Chiara; Chano, Tokuhiro; Madeo, Frank; Kroemer, Guido

    2011-08-15

    The tumor suppressor protein p53 tonically suppresses autophagy when it is present in the cytoplasm. This effect is phylogenetically conserved from mammals to nematodes, and human p53 can inhibit autophagy in yeast, as we show here. Bioinformatic investigations of the p53 interactome in relationship to the autophagy-relevant protein network underscored the possible relevance of a direct molecular interaction between p53 and the mammalian ortholog of the essential yeast autophagy protein Atg17, namely RB1-inducible coiled-coil protein 1 (RB1CC1), also called FAK family kinase-interacting protein of 200 KDa (FIP200). Mutational analyses revealed that a single point mutation in p53 (K382R) abolished its capacity to inhibit autophagy upon transfection into p53-deficient human colon cancer or yeast cells. In conditions in which wild-type p53 co-immunoprecipitated with RB1CC1/FIP200, p53 (K382R) failed to do so, underscoring the importance of the physical interaction between these proteins for the control of autophagy. In conclusion, p53 regulates autophagy through a direct molecular interaction with RB1CC1/FIP200, a protein that is essential for the very apical step of autophagy initiation.

  11. A p53-independent apoptotic mechanism of adenoviral mutant E1A was involved in its selective antitumor activity for human cancer

    Science.gov (United States)

    Fang, Lin; Cheng, Qian; Zhao, Jingjing; Ge, Yan; Zhu, Qi; Zhao, Min; Zhang, Jie; Zhang, Qi; Li, Liantao; Liu, Junjie; Zheng, Junnian

    2016-01-01

    The conserved regions (CR) of adenoviral E1A had been shown to be necessary for disruption of pRb-E2F transcription factor complexes and induction of the S phase. Here we constructed a mutant adenoviral E1A with Rb-binding ability absent (E1A 30-60aa and 120-127aa deletion, mE1A) and investigated its antitumor capacities in vitro and in vivo. The mE1A suppressed the viability of tumor cells as efficiently as the wild type E1A, and there was no cytotoxic effect on normal cells. Although the mE1A arrested tumor cell cycle with the same manner as E1A, the former played a different role on cell cycle regulation compared with E1A in normal cells, which might contribute to its selective antitumor activity. E1A and mE1A had accumulated inactive p53, decreased the expression of mdm2, Cdkn1a (also named p21), increased p21's nuclear distribution and induced tumor cell apoptosis in a p53-indenpent manner. Further, E1A or mE1A significantly suppressed tumor growth in subcutaneous hepatocellular carcinoma xenograft models. Especially, tumor-bearing mice treated with mE1A had higher survival rate than those treated with E1A. Our data demonstrated that mutant adenoviral E1A significantly induced tumor cell apoptosis in a p53-indenpednt manner and had selective tumor suppressing ability. The observations of adenoviral E1A mutant had provided a novel mechanism for E1A's complex activities during infection. PMID:27340782

  12. p53/miR-34a通路介导羽扇豆醇的抑制人膀胱癌T24细胞增殖作用%Anti-proliferative Effect of Lupeol on Human Bladder Cancer T24 Cell Line via p53/miR-34 a Signaling

    Institute of Scientific and Technical Information of China (English)

    郭敏; 刘佩; 郑国华; 邱振鹏

    2016-01-01

    Objective:To study the anti-proliferative effect of lupeol on human bladder cancer T24 cell line and the regulating mechanism for p53/miR-34a signaling. Methods:CCK-8 assay was performed to evaluate the effects of lupeol at different concentra-tions on cell viability in 24 h and 48 h. Caspase inhibitors were used to identify the subtypes of Caspase during lupeol induced cell death. The effects of lupeol on the expression of total p53 protein and miR-34a were evaluated by western blot and real-time PCR, re-spectively. The effects of lupeol on downstream targets of miR-34a were quantified by real-time PCR. Results:Lupeol could inhibit the proliferation of T24 cells in a dose-dependent manner. The IC50 of lupeol was (77. 23 ± 6. 78) μmol·L-1 in 24 h. Compared with the control group, lupeol could elevate the expressions of p53 and miR-34a (P<0. 01). Moreover, the mRNA expression of miR-34a tar-gets, Bcl-2, CD44 and c-Myc were significantly down-regulated after the treatment with lupeol (P<0. 01). Conclusion:Lupeol can inhibit T24 cell proliferation, which is related with the regulating effects on p53/miR-34a signaling.%目的::探讨羽扇豆醇对人膀胱癌T24细胞增殖的影响及对p53/miR-34a通路调控机制。方法:运用CCK-8法检测不同浓度羽扇豆醇(5~120μmol·L-1)分别作用24 h和48 h对T24细胞增殖的影响;运用CCK-8法结合Caspase抑制药确证参与羽扇豆醇诱导细胞死亡的Caspase亚型;分别运用荧光定量PCR(qPCR)和蛋白免疫印记评价羽扇豆醇对miR-34a及p53蛋白表达的影响;运用qPCR评价羽扇豆醇对miR-34a下游靶基因Bcl-2、CD44、c-Myc的mRNA表达的影响。结果: T24细胞经羽扇豆醇处理后,其细胞增殖受到明显抑制,且呈一定的剂量依赖性;药物作用24 h和48 h时羽扇豆醇的半抑制浓度(IC50)分别为(77.23±6.78),(64.58±4.23)μmol·L-1。与对照组相比,羽扇豆醇能够使T24细胞中p53蛋白表达

  13. The tumor suppressor p53 regulates autophagosomal and lysosomal biogenesis in lung cancer cells by targeting transcription factor EB.

    Science.gov (United States)

    Zhang, Zengli; Wang, Hongfeng; Ding, Qifeng; Xing, Yufei; Xu, Delai; Xu, Zhonghua; Zhou, Tong; Qian, Bin; Ji, Chenghong; Pan, Xue; Zhong, Anyuan; Ying, Zheng; Zhou, Caicun; Shi, Minhua

    2017-03-10

    The cellular protein degradation system, such as proteasomal or autophagy-lysosomal system plays an important role in the pathogenesis of a variety of human diseases including cancer. Transcription factor EB (TFEB) is a master transcriptional factor in the regulation of autophagy-lysosome pathway (ALP), and it has multiple biological functions including protein degradation, cell homeostasis and cell survival. In the present study we show that the tumor suppressor p53 can regulate TFEB nuclear translocation and activity in lung cancer cells. We found p53 deletion or chemical inhibition of p53 using pifithrin-α could promote the translocation of TFEB from cytoplasm to the nucleus, thus increased the TFEB-mediated lysosomal and autophagosomal biogenesis in lung cancer cells. Moreover, re-expression of p53 could decrease the expression levels of TFEB-targeting genes involved in ALP, and knockdown of TFEB could abolish the effect of p53 on the regulation of ALP gene expression. Taken together, our data indicate that p53 affects ALP through regulating TFEB nuclear translocation in lung cancer cells. Importantly, our study reveals a critical link between two keys factors in tumourigenesis and autophagy, and suggests a potential important role of p53-TFEB signaling axis in lung cancer.

  14. p53 isoforms change p53 paradigm

    OpenAIRE

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

    Directory of Open Access Journals (Sweden)

    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.

  16. The prognostic value of p53 positive in colorectal cancer: A retrospective cohort study.

    Science.gov (United States)

    Wang, Peng; Liang, Jianwei; Wang, Zheng; Hou, Huirong; Shi, Lei; Zhou, Zhixiang

    2017-05-01

    This retrospective cohort study aimed to discuss the prognostic value of p53 positive in colorectal cancer. A total of 124 consecutive patients diagnosed with colorectal cancer were evaluated at the National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College from 1 January 2009 to 31 December 2010. The expression of p53 in colorectal cancer was examined by immunohistochemistry. Based on the expression levels of p53, the 124 patients were divided into a p53 positive group and a p53 negative group. In this study, 72 patients were in the p53 positive group and 52 in the p53 negative group. The two groups were well balanced in gender, age, body mass index, American Society of Anesthesiologists scores, and number of lymph nodes harvested. p53 positive was associated with carcinoembryonic antigen ≥5 ng/mL ( p = 0.036), gross type ( p = 0.037), degree of tumor differentiation ( p = 0.026), pathological tumor stage ( p = 0.019), pathological node stage ( p = 0.004), pathological tumor-node-metastasis stage ( p = 0.017), nerve invasion ( p = 0.008), and vessel invasion ( p = 0.018). Tumor site, tumor size, and pathological pattern were not significantly different between these two groups. Disease-free survival and overall survival in the p53 positive group were significantly shorter than the p53 negative group ( p = 0.021 and 0.025, respectively). Colorectal cancer patients with p53 positive tended to be related to a higher degree of malignancy, advanced tumor-node-metastasis stage, and shorter disease-free survival and overall survival. p53 positive was independently an unfavorable prognostic marker for colorectal cancer patients.

  17. The flavonoid quercetin induces cell cycle arrest and mitochondria-mediated apoptosis in human cervical cancer (HeLa) cells through p53 induction and NF-κB inhibition.

    Science.gov (United States)

    Vidya Priyadarsini, R; Senthil Murugan, R; Maitreyi, S; Ramalingam, K; Karunagaran, D; Nagini, S

    2010-12-15

    With increasing use of plant-derived cancer chemotherapeutic agents, exploring the antiproliferative effects of phytochemicals has gained increasing momentum for anticancer drug design. The dietary phytochemical quercetin, modulates several signal transduction pathways associated with cell proliferation and apoptosis. The present study was undertaken to examine the effect of quercetin on cell viability, and to determine the molecular mechanism of quercetin-induced cell death by investigating the expression of Bcl-2 family proteins (Bcl-2, Bcl-xL, Mcl1, Bax, Bad, p-Bad), cytochrome C, Apaf-1, caspases, and survivin as well as the cell cycle regulatory proteins (p53, p21, cyclin D1), and NF-κB family members (p50, p65, IκB, p-IκB-α, IKKβ and ubiquitin ligase) in human cervical cancer (HeLa) cells. The results demonstrate that quercetin suppressed the viability of HeLa cells in a dose-dependent manner by inducing G2/M phase cell cycle arrest and mitochondrial apoptosis through a p53-dependent mechanism. This involved characteristic changes in nuclear morphology, phosphatidylserine externalization, mitochondrial membrane depolarization, modulation of cell cycle regulatory proteins and NF-κB family members, upregulation of proapoptotic Bcl-2 family proteins, cytochrome C, Apaf-1 and caspases, and downregulation of antiapoptotic Bcl-2 proteins and survivin. Quercetin that exerts opposing effects on different signaling networks to inhibit cancer progression is a classic candidate for anticancer drug design. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. A genome-wide siRNA screen for regulators of tumor suppressor p53 activity in human non-small lung cancer cells identifies components of the RNA splicing machinery as targets for anticancer treatment.

    Science.gov (United States)

    Siebring-van Olst, Ellen; Blijlevens, Maxime; de Menezes, Renee X; van der Meulen-Muileman, Ida H; Smit, Egbert F; van Beusechem, Victor W

    2017-03-13

    Reinstating wild-type tumor suppressor p53 activity could be a valuable option for the treatment of cancer. To contribute to development of new treatment options for non-small cell lung cancer (NSCLC), we performed genome-wide siRNA screens for determinants of p53 activity in NSCLC cells. We identified many genes not previously known to be involved in regulating p53 activity. Silencing p53 pathway inhibitor genes was associated with loss of cell viability. The largest functional gene cluster influencing p53 activity was mRNA splicing. Prominent p53 activation was observed upon silencing of specific spliceosome components, rather than by general inhibition of the spliceosome. Ten genes were validated as inhibitors of p53 activity in multiple NSCLC cell lines: genes encoding the Ras-pathway activator SOS1, the zinc finger protein TSHZ3, the mitochondrial membrane protein COX16 and the spliceosome components SNRPD3, SF3A3, SF3B1, SF3B6, XAB2, CWC22 and HNRNPL. Silencing these genes generally increased p53 levels, with distinct effects on CDKN1A expression, induction of cell cycle arrest and cell death. Silencing spliceosome components was associated with alternative splicing of MDM4 mRNA, which could contribute to activation of p53. In addition, silencing splice factors was particularly effective in killing NSCLC cells, albeit in a p53-independent manner. Interestingly, silencing SNRPD3 and SF3A3 exerted much stronger cytotoxicity to NSCLC cells than to lung fibroblasts, suggesting that these genes could represent useful therapeutic targets. This article is protected by copyright. All rights reserved.

  19. [Polymorphism in codon 72 of the p53 gene and cervico-uterine cancer risk in Mexico].

    Science.gov (United States)

    Suárez-Rincón, Angel Emillo; Morán-Moguel, María Cristina; Montoya-Fuentes, Héctor; Gallegos-Arreola, Martha Patricia; Sánchez-Corona, José

    2002-07-01

    A polymorphism at codon 72 in the p53 gen has been reported as a potential risk factor to cervical cancer (CC) because human papillomavirus (HPV) is more effective at degrading p53 Arg-72 than p53 Pro-72, making individuals homozygous for p53 Arg-72 seven times more likely to develop HPV-associated CC. As In Mexico the CC is a health public problem, we designed this study to determinate whether the p53 codon 72 polymorphism represent a risk factor to CC in our population. A case-controls study was performed. DNA was obtained from paraffin-embedded cervical fixed tissue samples. Analysis of the p53 genotype at position 72 was performed by polymerase chain reaction using specific primers and Accll digestion. Among cases with CC the proportions of the p53 genotypes at codon 72 were 0.05 to proline homozygous, 0.5 to heterozygous, and 0.45 to arginine-homozygous. In controls the proportions were 0.08, 0.62, and 0.31. X2 test showed no significant difference In the proportions. We conclude than In our population, as other worldwide countries, the homozygous for arginine at codon 72 of the p53 gene is not a risk factor to cervical cancer.

  20. Induction of antiproliferative effect by diosgenin through activation of p53,release of apoptosis-inducing factor (AIF) and modulation of caspase-3 activity in different human cancer cells

    Institute of Scientific and Technical Information of China (English)

    Cecile CORBIERE; Bertrand LIAGRE; Faraj TERRO; Jean-Louis BENEYTOUT

    2004-01-01

    Previously, we demonstrated that a plant steroid, diosgenin, altered cell cycle distribution and induced apoptosis in the human osteosarcoma 1547 cell line. The objective of this study was to investigate if the antiproliferative effect of diosgenin was similar for different human cancer cell lines such as laryngocarcinoma HEp-2 and melanoma M4Beu cells. Moreover, this work essentially focused on the mitochondrial pathway. We found that diosgenin had an important and similar antiproliferative effect on different types of cancer cells. In addition, our new results show that diosgenininduced apoptosis is caspase-3 dependent with a fall of mitochondrial membrane potential, nuclear localization of AIF and poly (ADP-ribose) polymerase cleavage. Diosgenin treatment also induces p53 activation and cell cycle arrest in the different cell lines studied.

  1. Overexpression of p53 Gene in Esophageal and Cervical Cancer and the Relationship with Radiotherapy Effects

    Institute of Scientific and Technical Information of China (English)

    张晓智; 王晓丽; 李旭

    2003-01-01

    Objective:To investigate the relationship between p53 protein overexpression in esophageal and cervical squamous cell cancer and their clinical radiosensitivity. Methods: The immuno-histochemical assays were done for 52 cases with esophageal and cervical squamous cell cancer. The relationship between the assay results and short-term radiotherapy was investigated. Results: p53 overer-pression was 52.38% and 35. 48% respectively, in esophageal cancer and cervical cancer;p53 over-expression in high differentiated squamous cell cancer was knver than these in moderate and poor differentiated cases(P0. 05). In the cases of cervical cancer, p53 overexpression had the less short-term effect(P0. 05).Conclusion:This study suggests that p53 gene has the certain relationship with tumor radiosensitivity.

  2. Regulation of the p53 response and its relationship to cancer.

    Science.gov (United States)

    Meek, David W

    2015-08-01

    p53 has been studied intensively as a major tumour suppressor that detects oncogenic events in cancer cells and eliminates them through senescence (a permanent non-proliferative state) or apoptosis. Consistent with this role, p53 activity is compromised in a high proportion of all cancer types, either through mutation of the TP53 gene (encoding p53) or changes in the status of p53 modulators. p53 has additional roles, which may overlap with its tumour-suppressive capacity, in processes including the DNA damage response, metabolism, aging, stem cell differentiation and fertility. Moreover, many mutant p53 proteins, termed 'gain-of-function' (GOF), acquire new activities that help drive cancer aggression. p53 is regulated mainly through protein turnover and operates within a negative-feedback loop with its transcriptional target, MDM2 (murine double minute 2), an E3 ubiquitin ligase which mediates the ubiquitylation and proteasomal degradation of p53. Induction of p53 is achieved largely through uncoupling the p53-MDM2 interaction, leading to elevated p53 levels. Various stress stimuli acting on p53 (such as hyperproliferation and DNA damage) use different, but overlapping, mechanisms to achieve this. Additionally, p53 activity is regulated through critical context-specific or fine-tuning events, mediated primarily through post-translational mechanisms, particularly multi-site phosphorylation and acetylation. In the present review, I broadly examine these events, highlighting their regulatory contributions, their ability to integrate signals from cellular events towards providing most appropriate response to stress conditions and their importance for tumour suppression. These are fascinating aspects of molecular oncology that hold the key to understanding the molecular pathology of cancer and the routes by which it may be tackled therapeutically.

  3. p53 binds human telomeric G-quadruplex in vitro.

    Science.gov (United States)

    Adámik, Matej; Kejnovská, Iva; Bažantová, Pavla; Petr, Marek; Renčiuk, Daniel; Vorlíčková, Michaela; Brázdová, Marie

    2016-01-01

    The tumor suppressor protein p53 is a key factor in genome stability and one of the most studied of DNA binding proteins. This is the first study on the interaction of wild-type p53 with guanine quadruplexes formed by the human telomere sequence. Using electromobility shift assay and ELISA, we show that p53 binding to telomeric G-quadruplexes increases with the number of telomeric repeats. Further, p53 strongly favors G-quadruplexes folded in potassium over those formed in sodium, thus indicating the telomeric G-quadruplex conformational selectivity of p53. The presence of the quadruplex-stabilizing ligand, N-methyl mesoporphyrin IX (NMM), increases p53 recognition of G-quadruplexes in potassium. Using deletion mutants and selective p53 core domain oxidation, both p53 DNA binding domains are shown to be crucial for telomeric G-quadruplex recognition.

  4. Aromatase, cyclooxygenase 2, HER-2/neu, and p53 as prognostic factors in endometrioid endometrial cancer

    NARCIS (Netherlands)

    Jongen, Vincent H. W. M.; Briet, Justine M.; de Jong, Renske A.; Joppe, Erna; ten Hoor, Klaske A.; Boezen, H. M.; Evans, Dean B.; Hollema, Harry; van der Zee, Ate G. J.; Nijman, Hans W.

    2009-01-01

    The prognostic value of aromatase, cyclooxygenase 2 (COX-2), HER-2/neu, and p53 expression was determined in endometrioid endometrial cancer. Tissue microarrays were constructed comprising samples from 315 endometrioid endometrial cancer patients. Expression of aromatase, COX-2, HER-2/neu, and p53 w

  5. Zn(II)-curc targets p53 in thyroid cancer cells.

    Science.gov (United States)

    Garufi, Alessia; D'Orazi, Valerio; Crispini, Alessandra; D'Orazi, Gabriella

    2015-10-01

    TP53 mutation is a common event in many cancers, including thyroid carcinoma. Defective p53 activity promotes cancer resistance to therapies and a more malignant phenotype, acquiring oncogenic functions. Rescuing the function of mutant p53 (mutp53) protein is an attractive anticancer therapeutic strategy. Zn(II)-curc is a novel small molecule that has been shown to target mutp53 protein in several cancer cells, but its effect in thyroid cancer cells remains unclear. Here, we investigated whether Zn(II)-curc could affect p53 in thyroid cancer cells with both p53 mutation (R273H) and wild-type p53. Zn(II)-curc induced mutp53H273 downregulation and reactivation of wild-type functions, such as binding to canonical target promoters and target gene transactivation. This latter effect was similar to that induced by PRIMA-1. In addition, Zn(II)-curc triggered p53 target gene expression in wild-type p53-carrying cells. In combination treatments, Zn(II)-curc enhanced the antitumor activity of chemotherapeutic drugs, in both mutant and wild-type-carrying cancer cells. Taken together, our data indicate that Zn(II)-curc promotes the reactivation of p53 in thyroid cancer cells, providing in vitro evidence for a potential therapeutic approach in thyroid cancers.

  6. Antigen-specific immunotherapy in ovarian cancer and p53 as tumor antigen

    NARCIS (Netherlands)

    Vermeij, Renee; Leffers, Ninke; Melief, Cornelis J.; Daemen, Toos; Nijman, Hans W.

    2012-01-01

    This review discusses the results of different immunization strategies, identifies possible drawbacks in study design and provides potential solutions for augmentation of clinical efficacy. A potential target for cancer immunotherapy is p53, as approximately 50% of ovarian cancer cells carry p53 mut

  7. The impact of p53 in predicting clinical outcome of breast cancer patients with visceral metastasis

    OpenAIRE

    Yang, P.; Du, C.W.; Kwan, M; Liang, S. X.; Zhang, G.J.

    2013-01-01

    In the study, we analyzed role of p53 in predicting outcome in visceral metastasis breast cancer (VMBC) patients. 97 consecutive VMBC patients were studied. P53 positivity rate was 29.9%. In the p53-negative group, median disease free survival (DFS), and time from primary breast cancer diagnosis to death (OS1), time from metastases to death (OS2) were 25, 42.5, and 13.5 months, respectively. In the p53-positive group, they were 10, 22, and 8 months, respectively. Statistically significant dif...

  8. CRIF1 enhances p53 activity via the chromatin remodeler SNF5 in the HCT116 colon cancer cell lines.

    Science.gov (United States)

    Yan, Hai-Xia; Zhang, Yan-Jun; Zhang, Yuan; Ren, Xue; Shen, Yu-Fei; Cheng, Mo-Bin; Zhang, Ye

    2017-02-21

    CR6-interacting factor 1 (CRIF1) is ubiquitously expressed in human tissues. CRIF1 was first identified as a Gadd45γ (also known as CR6)-interacting protein, and it was also identified in a human colon cancer cell line stably transformed with p53. These results suggested that CRIF1 functions in the nucleus with p53 and Gadd45 family proteins in the suppression of cell growth and tumor development. Here, we found that CRIF1 could be recruited to a specific region in the promoter of the p53 gene, eliciting an increase in the mRNA and protein levels of p53 as well as p53 functional target genes. These functions required CRIF1 to interact with SNF5. CRIF1 was further recruited to the upstream promoter region of the p53 gene to suppress cell cycle progression in HCT116 cells. To our knowledge, this is the first evidence indicating that SNF5 is indispensable for CRIF1-enhanced p53 activity and its function in the suppression of cell cycle arrest in human cancer cells.

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

    Directory of Open Access Journals (Sweden)

    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

  10. Knockdown of CDK2AP1 in primary human fibroblasts induces p53 dependent senescence.

    Directory of Open Access Journals (Sweden)

    Khaled N Alsayegh

    Full Text Available Cyclin Dependent Kinase-2 Associated Protein-1 (CDK2AP1 is known to be a tumor suppressor that plays a role in cell cycle regulation by sequestering monomeric CDK2, and targeting it for proteolysis. A reduction of CDK2AP1 expression is considered to be a negative prognostic indicator in patients with oral squamous cell carcinoma and also associated with increased invasion in human gastric cancer tissue. CDK2AP1 overexpression was shown to inhibit growth, reduce invasion and increase apoptosis in prostate cancer cell lines. In this study, we investigated the effect of CDK2AP1 downregulation in primary human dermal fibroblasts. Using a short-hairpin RNA to reduce its expression, we found that knockdown of CDK2AP1 in primary human fibroblasts resulted in reduced proliferation and in the induction of senescence associated beta-galactosidase activity. CDK2AP1 knockdown also resulted in a significant reduction in the percentage of cells in the S phase and an accumulation of cells in the G1 phase of the cell cycle. Immunocytochemical analysis also revealed that the CDK2AP1 knockdown significantly increased the percentage of cells that exhibited γ-H2AX foci, which could indicate presence of DNA damage. CDK2AP1 knockdown also resulted in increased mRNA levels of p53, p21, BAX and PUMA and p53 protein levels. In primary human fibroblasts in which p53 and CDK2AP1 were simultaneously downregulated, there was: (a no increase in senescence associated beta-galactosidase activity, (b decrease in the number of cells in the G1-phase and increase in number of cells in the S-phase of the cell cycle, and (c decrease in the mRNA levels of p21, BAX and PUMA when compared with CDK2AP1 knockdown only fibroblasts. Taken together, this suggests that the observed phenotype is p53 dependent. We also observed a prominent increase in the levels of ARF protein in the CDK2AP1 knockdown cells, which suggests a possible role of ARF in p53 stabilization following CDK2AP1

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

    Institute of Scientific and Technical Information of China (English)

    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

  12. Cooperativity of Rb, Brca1, and p53 in malignant breast cancer evolution.

    Directory of Open Access Journals (Sweden)

    Prashant Kumar

    Full Text Available Breast cancers that are "triple-negative" for the clinical markers ESR1, PGR, and HER2 typically belong to the Basal-like molecular subtype. Defective Rb, p53, and Brca1 pathways are each associated with triple-negative and Basal-like subtypes. Our mouse genetic studies demonstrate that the combined inactivation of Rb and p53 pathways is sufficient to suppress the physiological cell death of mammary involution. Furthermore, concomitant inactivation of all three pathways in mammary epithelium has an additive effect on tumor latency and predisposes highly penetrant, metastatic adenocarcinomas. The tumors are poorly differentiated and have histologic features that are common among human Brca1-mutated tumors, including heterogeneous morphology, metaplasia, and necrosis. Gene expression analyses demonstrate that the tumors share attributes of both Basal-like and Claudin-low signatures, two molecular subtypes encompassed by the broader, triple-negative class defined by clinical markers.

  13. Human papillomavirus and p53 protein immunoreactivity in condylomata acuminatum and squamous cell carcinoma of penis

    Institute of Scientific and Technical Information of China (English)

    Xin-Hua ZHANG; Gui-Qin SUN; Yu YANG; Tai-He ZHANG

    2001-01-01

    To determine the immunoreactive pattem of human papillomavirus (HPV) antigen and p53 protein in condylomata acuminatum (CA) and squamous cell carcinoma (SCC) of penis. Methods: Immunohistochemistry for HPV and p53 were performed in 40 specimens of formalin fixed, paraffin embedded tissues using a polyclonal (rabbit) antibody against HPV and a monoclonal (mouse) antibody against human p53 protein. Twenty one cases of CA and nineteen cases of SCC were examined. Results: HPV antigen was detected in all 21 CA and 2 penile SCC. p53 protein overexpression was observed in 12 of 19 (63%) SCC in which 6 cases were strong positive. Five of 21 CA (24%)showed low-grade p53 protein overexpression. Conclusion: CA is related to HPV infection and some cases show p53 protein low-grade overexpression. In contrast, p53 protein overexpression is common in penile SCC, which is seldom related to HPV infection.

  14. p53 deficiency induces cancer stem cell pool expansion in a mouse model of triple-negative breast tumors.

    Science.gov (United States)

    Chiche, A; Moumen, M; Romagnoli, M; Petit, V; Lasla, H; Jézéquel, P; de la Grange, P; Jonkers, J; Deugnier, M-A; Glukhova, M A; Faraldo, M M

    2016-10-24

    Triple-negative breast cancer is a heterogeneous disease characterized by the expression of basal cell markers, no estrogen or progesterone receptor expression and a lack of HER2 overexpression. Triple-negative tumors often display activated Wnt/β-catenin signaling and most have impaired p53 function. We studied the interplay between p53 loss and Wnt/β-catenin signaling in stem cell function and tumorigenesis, by deleting p53 from the mammary epithelium of K5ΔNβcat mice displaying a constitutive activation of Wnt/β-catenin signaling in basal cells. K5ΔNβcat transgenic mice present amplification of the basal stem cell pool and develop triple-negative mammary carcinomas. The loss of p53 in K5ΔNβcat mice led to an early expansion of mammary stem/progenitor cells and accelerated the formation of triple-negative tumors. In particular, p53-deficient tumors expressed high levels of integrins and extracellular matrix components and were enriched in cancer stem cells. They also overexpressed the tyrosine kinase receptor Met, a feature characteristic of human triple-negative breast tumors. The inhibition of Met kinase activity impaired tumorsphere formation, demonstrating the requirement of Met signaling for cancer stem cell growth in this model. Human basal-like breast cancers with predicted mutated p53 status had higher levels of MET expression than tumors with wild-type p53. These results connect p53 loss and β-catenin activation to stem cell regulation and tumorigenesis in triple-negative cancer and highlight the role of Met signaling in maintaining cancer stem cell properties, revealing new cues for targeted therapies.Oncogene advance online publication, 24 October 2016; doi:10.1038/onc.2016.396.

  15. Class I histone deacetylases regulate p53/NF-κB crosstalk in cancer cells.

    Science.gov (United States)

    Schäfer, Claudia; Göder, Anja; Beyer, Mandy; Kiweler, Nicole; Mahendrarajah, Nisintha; Rauch, Anke; Nikolova, Teodora; Stojanovic, Natasa; Wieczorek, Martin; Reich, Thomas R; Tomicic, Maja T; Linnebacher, Michael; Sonnemann, Jürgen; Dietrich, Sascha; Sellmer, Andreas; Mahboobi, Siavosh; Heinzel, Thorsten; Schneider, Günter; Krämer, Oliver H

    2017-01-01

    The transcription factors NF-κB and p53 as well as their crosstalk determine the fate of tumor cells upon therapeutic interventions. Replicative stress and cytokines promote signaling cascades that lead to the co-regulation of p53 and NF-κB. Consequently, nuclear p53/NF-κB signaling complexes activate NF-κB-dependent survival genes. The 18 histone deacetylases (HDACs) are epigenetic modulators that fall into four classes (I-IV). Inhibitors of histone deacetylases (HDACi) become increasingly appreciated as anti-cancer agents. Based on their effects on p53 and NF-κB, we addressed whether clinically relevant HDACi affect the NF-κB/p53 crosstalk. The chemotherapeutics hydroxyurea, etoposide, and fludarabine halt cell cycle progression, induce DNA damage, and lead to DNA fragmentation. These agents co-induce p53 and NF-κB-dependent gene expression in cell lines from breast and colon cancer and in primary chronic lymphatic leukemia (CLL) cells. Using specific HDACi, we find that the class I subgroup of HDACs, but not the class IIb deacetylase HDAC6, are required for the hydroxyurea-induced crosstalk between p53 and NF-κB. HDACi decrease the basal and stress-induced expression of p53 and block NF-κB-regulated gene expression. We further show that class I HDACi induce senescence in pancreatic cancer cells with mutant p53.

  16. PRIMA-1Met suppresses colorectal cancer independent of p53 by targeting MEK.

    Science.gov (United States)

    Lu, Tao; Zou, Yanmei; Xu, Guogang; Potter, Jane A; Taylor, Garry L; Duan, Qiuhong; Yang, Qin; Xiong, Huihua; Qiu, Hong; Ye, Dawei; Zhang, Peng; Yu, Shiying; Yuan, Xianglin; Zhu, Feng; Wang, Yihua; Xiong, Hua

    2016-12-13

    PRIMA-1Met is the methylated PRIMA-1 (p53 reactivation and induction of massive apoptosis) and could restore tumor suppressor function of mutant p53 and induce p53 dependent apoptosis in cancer cells harboring mutant p53. However, p53 independent activity of PRIMA-1Met remains elusive. Here we reported that PRIMA-1Met attenuated colorectal cancer cell growth irrespective of p53 status. Kinase profiling revealed that mitogen-activated or extracellular signal-related protein kinase (MEK) might be a potential target of PRIMA-1Met. Pull-down binding and ATP competitive assay showed that PRIMA-1Met directly bound MEK in vitro and in cells. Furthermore, the direct binding sites of PRIMA-1Met were explored by using a computational docking model. Treatment of colorectal cancer cells with PRIMA-1Met inhibited p53-independent phosphorylation of MEK, which in turn impaired anchorage-independent cell growth in vitro. Moreover, PRIMA-1Met suppressed colorectal cancer growth in xenograft mouse model by inhibiting MEK1 activity.Taken together, our findings demonstrate a novel p53-independent activity of PRIMA-1Met to inhibit MEK and suppress colorectal cancer growth.

  17. A RUNX2-Mediated Epigenetic Regulation of the Survival of p53 Defective Cancer Cells.

    Science.gov (United States)

    Shin, Min Hwa; He, Yunlong; Marrogi, Eryney; Piperdi, Sajida; Ren, Ling; Khanna, Chand; Gorlick, Richard; Liu, Chengyu; Huang, Jing

    2016-02-01

    The inactivation of p53 creates a major challenge for inducing apoptosis in cancer cells. An attractive strategy is to identify and subsequently target the survival signals in p53 defective cancer cells. Here we uncover a RUNX2-mediated survival signal in p53 defective cancer cells. The inhibition of this signal induces apoptosis in cancer cells but not non-transformed cells. Using the CRISPR technology, we demonstrate that p53 loss enhances the apoptosis caused by RUNX2 knockdown. Mechanistically, RUNX2 provides the survival signal partially through inducing MYC transcription. Cancer cells have high levels of activating histone marks on the MYC locus and concomitant high MYC expression. RUNX2 knockdown decreases the levels of these histone modifications and the recruitment of the Menin/MLL1 (mixed lineage leukemia 1) complex to the MYC locus. Two inhibitors of the Menin/MLL1 complex induce apoptosis in p53 defective cancer cells. Together, we identify a RUNX2-mediated epigenetic mechanism of the survival of p53 defective cancer cells and provide a proof-of-principle that the inhibition of this epigenetic axis is a promising strategy to kill p53 defective cancer cells.

  18. A RUNX2-Mediated Epigenetic Regulation of the Survival of p53 Defective Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Min Hwa Shin

    2016-02-01

    Full Text Available The inactivation of p53 creates a major challenge for inducing apoptosis in cancer cells. An attractive strategy is to identify and subsequently target the survival signals in p53 defective cancer cells. Here we uncover a RUNX2-mediated survival signal in p53 defective cancer cells. The inhibition of this signal induces apoptosis in cancer cells but not non-transformed cells. Using the CRISPR technology, we demonstrate that p53 loss enhances the apoptosis caused by RUNX2 knockdown. Mechanistically, RUNX2 provides the survival signal partially through inducing MYC transcription. Cancer cells have high levels of activating histone marks on the MYC locus and concomitant high MYC expression. RUNX2 knockdown decreases the levels of these histone modifications and the recruitment of the Menin/MLL1 (mixed lineage leukemia 1 complex to the MYC locus. Two inhibitors of the Menin/MLL1 complex induce apoptosis in p53 defective cancer cells. Together, we identify a RUNX2-mediated epigenetic mechanism of the survival of p53 defective cancer cells and provide a proof-of-principle that the inhibition of this epigenetic axis is a promising strategy to kill p53 defective cancer cells.

  19. Apigenin causes G(2)/M arrest associated with the modulation of p21(Cip1) and Cdc2 and activates p53-dependent apoptosis pathway in human breast cancer SK-BR-3 cells.

    Science.gov (United States)

    Choi, Eun Jeong; Kim, Gun-Hee

    2009-04-01

    We studied the effects of apigenin on the cell cycle distribution and apoptosis of human breast cancer cells and explored the mechanisms underlying these effects. We first investigated the antiproliferative effects in SK-BR-3 cells exposed to between 1 and 100 microM apigenin for 24, 48 and 72 h. Apigenin significantly inhibited cell proliferation at concentrations over 50 microM, regardless of exposure time (P<.05), and resulted in significant cell cycle arrest in the G(2)/M phase after 48 h of treatment at high concentrations (50 and 100 microM; P<.05). To investigate the regulatory proteins of cell cycle arrest affected by apigenin, we treated cells with 50 and 100 microM apigenin for 72 h. Apigenin caused a slight decrease in cyclin D and cyclin E expression, with no change in CDK2 and CDK4. In addition, the apigenin-induced accumulation of the cell population in the G(2)/M phase resulted in a decrease in CDK1 together with cyclin A and cyclin B. In an additional study, apigenin also increased the accumulation of p53 and further enhanced the level of p21(Cip1), with no change in p27(Kip1). The expression of Bax and cytochrome c of p53 downstream target was increased markedly at high concentration treatment over 50 microM apigenin. Based on our findings, the mechanism by which apigenin causes cell cycle arrest via the regulation of CDK1 and p21(Cip1) and induction of apoptosis seems to be involved in the p53-dependent pathway.

  20. Pre-irradiation with low-dose 12C6+beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were signifi-cantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30%-60%, 20%-130% and 30%-70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

  1. Pre-irradiation with low-dose 12C6+ beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

    Science.gov (United States)

    Liu, Bing; Zhang, Hong; Li, Wenjian; Li, Qiang; Zhou, Guangming; Xie, Yi; Hao, Jifang; Min, Fengling; Zhou, Qingming; Duan, Xin

    2007-04-01

    The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOI of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30% 60%, 20% 130% and 30% 70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

  2. Pre-irradiation with low-dose 12C6+ beam significantly enhances the efficacy of AdCMV-p53 gene therapy in human non-small lung cancer

    Institute of Scientific and Technical Information of China (English)

    LIU Bing; DUAN Xin; ZHANG Hong; LI WenJian; LI Qiang; ZHOU GuangMing; XIE Yi; HAO JiFang; MIN FengLing; ZHOU QingMing

    2007-01-01

    The combination of ionizing radiation and gene therapy has been investigated. However, there are very few reports about the combination of heavy-ion irradiation and gene therapy. To determine if the pre-exposure to low-dose heavy ion beam enhances the suppression of AdCMV-p53 on non-small lung cancer (NSLC), the cells pre-irradiated or non-irradiated were infected with 20, 40 MOl of AdCMV-p53. Survival fraction and the relative biology effect (RBE) were determined by clonogenic assay. The results showed that the proportions of p53 positive cells in 12C6+ beam induced AdCMV-p53 infected cells were more than 90%, which were significantly more than those in γ-ray induced AdCMV-p53 infected cells. The pre-exposure to low-dose 12C6+ beam significantly prevented the G0/G1 arrest and activated G2/M checkpoints. The pre-exposure to 12C6+ beam significantly improved cell to apoptosis. RBEs for the 12C6+ + AdCMV-p53 infection groups were 30%-60%, 20% -130% and 30%-70% more than those for the 12C6+-irradiated only, AdCMV-p53 infected only, and γ-irradiation induced AdCMVp53 infected groups, respectively. The data suggested that the pre-exposure to low-dose 12C6+ beam significantly promotes exogenous p53 expression in NSLC, and the suppression of AdCMV-p53 gene therapy on NSLC.

  3. Increased Arf/p53 activity in stem cells, aging and cancer.

    Science.gov (United States)

    Carrasco-Garcia, Estefania; Moreno, Manuel; Moreno-Cugnon, Leire; Matheu, Ander

    2017-04-01

    Arf/p53 pathway protects the cells against DNA damage induced by acute stress. This characteristic is the responsible for its tumor suppressor activity. Moreover, it regulates the chronic type of stress associated with aging. This is the basis of its anti-aging activity. Indeed, increased gene dosage of Arf/p53 displays elongated longevity and delayed aging. At a cellular level, it has been recently shown that increased dosage of Arf/p53 delays age-associated stem cell exhaustion and the subsequent decline in tissue homeostasis and regeneration. However, p53 can also promote aging if constitutively activated. In this context, p53 reduces tissue regeneration, which correlates with premature exhaustion of stem cells. We discuss here the current evidence linking the Arf/p53 pathway to the processes of aging and cancer through stem cell regulation. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  4. p53 Expression in Oral cancer: A study of 50 cases

    Directory of Open Access Journals (Sweden)

    S Ghanghoria

    2015-03-01

    Full Text Available Background: Oral cancer is the sixth most common cancer in the world. P53 mutations are associated with the development of oral squamous cell carcinomas. This study is to determine the presence of p53 oncogene expression in cases of oral malignant, premalignant and benign lesions and to show association of p53 oncogene and lymph node enlargement in malignant lesion.Materials and Methods: Four to five micron-thick sections of formalin fixed, paraffin embedded biopsy material from various intra-oral sites of 50 patients were collected, in the series of 50 cases, 35 oral squamous cell carcinoma, 10 dysplastic lesions and 05 hyperplastic lesions were assessed for p53 expression. The tissue sections were immunohistochemically analyzed for the expression of p53 gene.Results: Out of 50; 22/35 (63% cases of squamous cell carcinoma, 02/10 (20% cases of dysplasia (20%, were positive for p53. Five hyperplastic lesions were negative for p53. The P53 protein was not identified in benign lesion.Conclusion: Results indicate that p53 over-expression is seen in oral squamous cell carcinomas. It is a significant marker of carcinogenesis and can be considered as an important marker for clinical evaluation, diagnosis as well as prognosis of disease.Journal of Pathology of Nepal (2015 Vol. 5, 747-751

  5. Prognostic value of p53 for high risk superficial bladder cancer with long-term followup.

    NARCIS (Netherlands)

    Moonen, P.M.J.; Balken-Ory, B. van; Kiemeney, L.A.L.M.; Schalken, J.A.; Witjes, J.A.

    2007-01-01

    PURPOSE: The risk of muscle invasive disease in a high risk patient with superficial bladder cancer is up to 50%. Identifying patients at risk for progression remains an unsolved problem. A suggested prognosticator is mutations in the p53 tumor suppressor gene. We determined the value of p53 mutatio

  6. Analysis of a p53 Mutation Associated with Cancer Susceptibility for Biochemistry and Genetic Laboratory Courses

    Science.gov (United States)

    Soto-Cruz, Isabel; Legorreta-Herrera, Martha

    2009-01-01

    We have devised and implemented a module for an upper division undergraduate laboratory based on the amplification and analysis of a p53 polymorphism associated with cancer susceptibility. First, students collected a drop of peripheral blood cells using a sterile sting and then used FTA cards to extract the genomic DNA. The p53 region is then PCR…

  7. Analysis of a p53 Mutation Associated with Cancer Susceptibility for Biochemistry and Genetic Laboratory Courses

    Science.gov (United States)

    Soto-Cruz, Isabel; Legorreta-Herrera, Martha

    2009-01-01

    We have devised and implemented a module for an upper division undergraduate laboratory based on the amplification and analysis of a p53 polymorphism associated with cancer susceptibility. First, students collected a drop of peripheral blood cells using a sterile sting and then used FTA cards to extract the genomic DNA. The p53 region is then PCR…

  8. Immunohistochemical study of p53, pRb, p16 in esophageal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zo, Jae Ill; Zo, Kyung Ja; Park, Jong Ho; Kim, Mi Hee [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1998-01-01

    To confirm the expression of molecular genetic alterations of p53, pRb, p16 in esophageal cancer and to investigate the expression of p53, pRb, p16 in esophageal cancer according to the pathologic steps of carcinogenesis, immuno-histochemistry was performed in 15 resected esophageal cancer specimens with multiple separated lesions after pathologic mapping. The accumulation of mutant p53 was observed in 60 % of dysplasia and 47 % of invasive cancer, while pRb was not detected in 91 % of dysplasia and 72.7 % of invasive cancer. But p16 was not observed in 0 % in dysplasia and 7 % of invasive cancer. But p16 was not observed in 0 % in dysplasia and 28.6 % in invasive cancer. There was no simultaneous negative pRb and p16 expression. There was no relations between p53 and p16, pRb. As a results, the expression of p53, pRb, p16 was co-related well with molecular genetic changes and inactivation of p53, pRb, p16 was co-related well with molecular genetic changes and inactivation of p53 and pRb was common and early event in esophageal carcinogenesis in Korea, but inactivation of p16 was a infrequent change. (author). 17 refs., 2 tabs., 7 figs

  9. Deficiency in p53 is required for doxorubicin induced transcriptional activation of NF-small ka, CyrillicB target genes in human breast cancer

    NARCIS (Netherlands)

    Dalmases, A.; Gonzalez, I.; Menendez, S.; Arpi, O.; Corominas, J.; Servitja, S.; Tusquets, I.; Chamizo, C.; Rincon, R.; Espinosa, L.; Bigas, A.; Eroles, P.; Furriol, J.; Lluch, A.; Rovira, A.; Albanell, J.; Rojo, F.

    2014-01-01

    NF-small ka, CyrillicB has been linked to doxorubicin resistance in breast cancer patients. NF-small ka, CyrillicB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined; however its functional relevance at transcriptional level on NF-small ka

  10. Deficiency in p53 is required for doxorubicin induced transcriptional activation of NF-small ka, CyrillicB target genes in human breast cancer

    NARCIS (Netherlands)

    Dalmases, A.; Gonzalez, I.; Menendez, S.; Arpi, O.; Corominas, J.; Servitja, S.; Tusquets, I.; Chamizo, C.; Rincon, R.; Espinosa, L.; Bigas, A.; Eroles, P.; Furriol, J.; Lluch, A.; Rovira, A.; Albanell, J.; Rojo, F.

    2014-01-01

    NF-small ka, CyrillicB has been linked to doxorubicin resistance in breast cancer patients. NF-small ka, CyrillicB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined; however its functional relevance at transcriptional level on NF-small

  11. Clinical significance of different types of p53 gene alteration in surgically treated prostate cancer.

    Science.gov (United States)

    Kluth, Martina; Harasimowicz, Silvia; Burkhardt, Lia; Grupp, Katharina; Krohn, Antje; Prien, Kristina; Gjoni, Jovisa; Haß, Thomas; Galal, Rami; Graefen, Markus; Haese, Alexander; Simon, Ronald; Hühne-Simon, Julia; Koop, Christina; Korbel, Jan; Weischenfeld, Joachim; Huland, Hartwig; Sauter, Guido; Quaas, Alexander; Wilczak, Waldemar; Tsourlakis, Maria-Christina; Minner, Sarah; Schlomm, Thorsten

    2014-09-15

    Despite a multitude of p53 immunohistochemistry (IHC) studies, data on the combined effect of nuclear p53 protein accumulation and TP53 genomic inactivation are lacking for prostate cancer. A tissue microarray including 11,152 prostate cancer samples was analyzed by p53 IHC and fluorescence in situ hybridization. Nuclear p53 accumulation was found in 10.1% of patients including 1.4% with high-level and 8.7% with low-level immunostaining. TP53 sequencing revealed that 17 of 22 (77%) cases with high-level p53 immunostaining, but only 3% (1 of 31) low-level p53 cases carried putative dominant-negative mutations. TP53 deletions occurred in 14.8% of cancers. Both deletions and protein accumulation were linked to unfavorable tumor phenotype and prostate specific antigen (PSA) recurrence (pp53 positivity (8.7%) had identical risks of PSA recurrence, which were markedly higher than in cancers without p53 alterations (pp53 deletion and low-level p53 positivity (1.5%) had a worse prognosis than patients with only one of these alterations (pp53 immunostaining or homozygous inactivation through deletion of one allele and disrupting translocation involving the second allele had the worst outcome, independent from clinical and pathological parameters. These data demonstrate a differential clinical impact of various TP53 alterations in prostate cancer. Strong p53 immunostaining-most likely accompanying dominant negative or oncogenic p53 mutation-has independent prognostic relevance and may thus represent a clinical useful molecular feature of prostate cancer.

  12. Human T-cell leukemia virus I tax protein sensitizes p53-mutant cells to DNA damage.

    Science.gov (United States)

    Mihaylova, Valia T; Green, Allison M; Khurgel, Moshe; Semmes, Oliver J; Kupfer, Gary M

    2008-06-15

    Mutations in p53 are a common cause of resistance of cancers to standard chemotherapy and, thus, treatment failure. Reports have shown that Tax, a human T-cell leukemia virus type I encoded protein that has been associated with genomic instability and perturbation of transcription and cell cycle, sensitizes HeLa cells to UV treatment. The extent to which Tax can sensitize cells and the mechanism by which it exerts its effect are unknown. In this study, we show that Tax sensitizes p53-mutant cells to a broad range of DNA-damaging agents, including mitomycin C, a bifunctional alkylator, etoposide, a topoisomerase II drug, and UV light, but not ionizing radiation, a double-strand break agent, or vinblastine, a tubulin poison. Tax caused hypersensitivity in all p53-deleted cell lines and several, but not all, mutant-expressed p53-containing cell lines, while unexpectedly being protective in p53 wild-type (wt) cells. The effect observed in p53-deleted lines could be reversed for this by transfection of wt p53. We also show that Tax activates a p53-independent proapoptotic program through decreased expression of the retinoblastoma protein and subsequent increased E2F1 expression. The expression of several proapoptotic proteins was also induced by Tax, including Puma and Noxa, culminating in a substantial increase in Bax dimerization. Our results show that Tax can sensitize p53-mutant cells to DNA damage while protecting p53 wt cells, a side benefit that might result in reduced toxicity in normal cells. Such studies hold the promise of a novel adjunctive therapy that could make cancer chemotherapy more effective.

  13. Gain-of-function of mutant p53: mutant p53 enhances cancer progression by inhibiting KLF17 expression in invasive breast carcinoma cells.

    Science.gov (United States)

    Ali, Amjad; Shah, Abdus Saboor; Ahmad, Ayaz

    2014-11-01

    Kruppel-like-factor 17 (KLF17) is a negative regulator of metastasis and epithelial-mesenchymal-transition (EMT). However, its expression is downregulated in metastatic breast cancer that contains p53 mutations. Here, we show that mutant-p53 plays a key role to suppress KLF17 and thereby enhances cancer progression, which defines novel gain-of-function (GOF) of mutant-p53. Mutant-p53 interacts with KLF17 and antagonizes KLF17 mediated EMT genes transcription. Depletion of KLF17 promotes cell viability, decreases apoptosis and induces drug resistance in metastatic breast cancer cells. KLF17 suppresses cell migration and invasion by decreasing CD44, PAI-1 and Cyclin-D1 expressions. Taken together, our results show that KLF17 is important for the suppression of metastasis and could be a potential therapeutic target during chemotherapy.

  14. Transcriptome profiling identifies genes and pathways deregulated upon floxuridine treatment in colorectal cancer cells harboring GOF mutant p53

    Directory of Open Access Journals (Sweden)

    Arindam Datta

    2016-06-01

    Full Text Available Mutation in TP53 is a common genetic alteration in human cancers. Certain tumor associated p53 missense mutants acquire gain-of-function (GOF properties and confer oncogenic phenotypes including enhanced chemoresistance. The colorectal cancers (CRC harboring mutant p53 are generally aggressive in nature and difficult to treat. To identify a potential gene expression signature of GOF mutant p53-driven acquired chemoresistance in CRC, we performed transcriptome profiling of floxuridine (FUdR treated SW480 cells expressing mutant p53R273H (GEO#: GSE77533. We obtained several genes differentially regulated between FUdR treated and untreated cells. Further, functional characterization and pathway analysis revealed significant enrichment of crucial biological processes and pathways upon FUdR treatment in SW480 cells. Our data suggest that in response to chemotherapeutics treatment, cancer cells with GOF mutant p53 can modulate key cellular pathways to withstand the cytotoxic effect of the drugs. The genes and pathways identified in the present study can be further validated and targeted for better chemotherapy response in colorectal cancer patients harboring mutant p53.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. P53 and Ki-67 as prognostic markers in triple-negative breast cancer patients

    Science.gov (United States)

    Pan, Yunbao; Yuan, Yufen; Liu, Guoshi; Wei, Yongchang

    2017-01-01

    Triple-negative breast cancer (TNBC) is an aggressive subgroup of breast cancer lack of effective target therapy. This study was to investigate the prognostic role of p53 and Ki-67 in 156 cases of TNBC patients. Logistic regression analysis was used to examine the association between clinical parameters and recurrence. Univariate and multivariate analyses were used to examine the association between clinical characteristics and disease-free survival (DFS) or overall survival (OS). Survival analyses using the Kaplan-Meier method were performed to examine the association between p53/Ki-67 and DFS and OS. Our data showed that p53 was positive in 71.3% and the Ki-67 high index was in 82.8% of TNBC. Elevated p53 and Ki-67 were associated with histological grade. The tumor size, lymph node involvement, and p53 expression are associated with risk of recurrence. Tumor size, lymph node involvement, family history, Ki-67 and p53 are independent variables associated with either DFS or OS. TNBC patients with positive p53 or Ki-67 high index or family history of cancer have a significant association with worse prognosis. This study suggests that p53, Ki-67 and family history are useful prognostic markers in TNBC. PMID:28235003

  17. HER-2 positive and p53 negative breast cancers are associated with poor prognosis.

    LENUS (Irish Health Repository)

    2011-06-01

    p53 and HER-2 coexpression in breast cancer has been controversial. These markers were tested using immunohistochemistry and HercepTest. HER-2 expression is related to reduced breast cancer survival (p = .02) . p53 expression relates to HER-2 expression (p = .029). Coexpression between p53 and HER-2 has no relation to prognosis. On univariate and multivariate analysis, combination of HER-2 positive and p53 negative expression was associated with a poor prognosis (p = .018 and p = .027, respectively), while the combination of HER-2 negative and p53 positive expression was associated with a favorable prognosis (p = .022 and p = .010, respectively). Therefore the expression of these markers should be considered collectively.

  18. HER-2 positive and p53 negative breast cancers are associated with poor prognosis.

    LENUS (Irish Health Repository)

    2012-02-01

    p53 and HER-2 coexpression in breast cancer has been controversial. These markers were tested using immunohistochemistry and HercepTest. HER-2 expression is related to reduced breast cancer survival (p = .02) . p53 expression relates to HER-2 expression (p = .029). Coexpression between p53 and HER-2 has no relation to prognosis. On univariate and multivariate analysis, combination of HER-2 positive and p53 negative expression was associated with a poor prognosis (p = .018 and p = .027, respectively), while the combination of HER-2 negative and p53 positive expression was associated with a favorable prognosis (p = .022 and p = .010, respectively). Therefore the expression of these markers should be considered collectively.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. DETECTION OF p53 GENE MUTATION IN PLASMA OF PATIENTS WITH GASTRIC CANCER

    Institute of Scientific and Technical Information of China (English)

    苏鹏程; 李子禹; 张连海; 万文徽; 任晖; 张桂国; 王怡; 邓国仁; 季加孚

    2004-01-01

    Objective: To investigated p53 gene mutation in plasma of gastric cancer patients. Methods: DNA extracted from plasma and matched tumor and tumor-adjacent non-cancerous tissues of 96 gastric cancer patients, and DNA from 20 healthy volunteers were studied. Exon 5, 6, 7, and 8 of p53 were amplified by Polymerase Chain Reaction (PCR). The mutation status was analyzed by denaturing high-performance liquid chromatography (DHPLC), followed by direct sequencing of cases with aberrant chromatographic patterns. Results: Heterozygous mutations of p53 gene were detected in 19.9% (19/96) of primary tumor tissues and 5.2% (5/96) of corresponding plasma. All p53 gene mutations detected in plasma DNA consisted with mutations in the matched primary tumor samples. Neither the tumor-adjacent gastric mucosa tissues nor control plasma from healthy volunteers showed p53 gene mutation. No correlation was found between p53 mutation status and clinicopathological features of gastric cancer patients. Conclusion: p53 gene mutation in plasma can be detected in tissues and plasma of gastric cancer patients, which could be applied in screening and surveillance of this disease.

  1. DETECTION OF p53 GENE MUTATION OF BRONCHOSCOPIC SAMPLIES IN THE PATIENTS SUSPECTED TO LUNG CANCER

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To determine the feasibility of detecting p53 gene mutations for early diagnosis of lung cancer using the samples from bronchoscopic examination. Methods: Point mutations of the exon 5-8 of p53 gene were detected in 85 bronchoscopic samples of 35 patients suspected to be lung cancer using silver staining PCR-SSCP. Results: p53 gene mutations were founded in 10 of 35 patients(28.6%). The incidence of p53 gene mutations (14.9%) was obviously higher than the cytological positive incidence(2.9%) in samples of sputum, bronchoalveolar lavage and brush, especially for the sputum(27.7%). In the bronchoscopic biopsy specimens, the incidence of p53 gene mutations (12.5%) was lower than that of pathologic positive result (50.0%). However, in view of all the bronchoscopic samples, there was no statistically difference between cytopathologic positive results (11.8%) and the incidence of p53 gene mutations (14.1%). Although the p53 mutations were most common in the samples from the patients bronchoscopically manifested as neoplasm compared with other manifestations, there was no statistical difference. It is valuable to notice that 3 patients with p53 gene mutation merely presented as bronchial inflammation in bronchoscope. Conclusion: Results indicated that the value of detecting p53 gene mutation for the diagnosis of lung cancer using the bronchoscopic samples was more superior to cytological examination and detection of p53 gene mutations in post-bronchoscopic sputum was easy and effective, may be used as a valuable method for early diagnosis of lung cancer.

  2. DN-R175H p53 mutation is more effective than p53 interference in inducing epithelial disorganization and activation of proliferation signals in human carcinoma cells: role of E-cadherin.

    Science.gov (United States)

    Rieber, Manuel; Strasberg Rieber, Mary

    2009-10-01

    One of the hallmarks of carcinomas is epithelial disorganization, linked to overexpression of matrix metalloproteases (MMP) like MMP-9, loss of intercellular E-cadherin and activation of epidermal growth receptor (EGFR/erbB1). Since the p53 tumor suppressor pathway is inactivated in most human cancers due to gene mutations or defective wt p53 signaling, we now investigated in human wt p53 breast carcinoma MCF-7 cells, whether single treatment with the p53 transactivation pharmacological inhibitor pifithrin-alpha, transient p53 siRNA interference or stable insertion of a dominant-negative (DN) R175H p53 mutant increase: (i) EGFR/erbB1 activation, (ii) MMP-9 expression and (iii) loss of surface E-cadherin. Transient abrogation of wt p53 function increased phosphorylation of EGFR/erbB1 and MMP-9 expression. However, all these effects were much more pronounced in cells stably transduced with the dominant negative-Arg-175His mutant p53 (DN-R175H mutant p53), which also showed loss of epithelial cytoarchitecture and extensive E-cadherin downregulation. Collectively, these results support the notion that the DN-R175H mutant p53 exerts a gain of oncogenic function by promoting disruption of E-cadherin intercellular contacts and activation of proliferation signals. Our data suggests that epithelial shape and growth control are unequally affected depending on how wt p53 function is impaired and whether partial or full tumor suppressor activity is lost.

  3. Apigenin-induced prostate cancer cell death is initiated by reactive oxygen species and p53 activation.

    Science.gov (United States)

    Shukla, Sanjeev; Gupta, Sanjay

    2008-05-15

    Apigenin, a plant flavone, potentially activates wild-type p53 and induces apoptosis in cancer cells. We conducted detailed studies to understand its mechanism of action. Exposure of human prostate cancer 22Rv1 cells, harboring wild-type p53, to growth-suppressive concentrations (10-80 microM) of apigenin resulted in the stabilization of p53 by phosphorylation on critical serine sites, p14ARF-mediated downregulation of MDM2 protein, inhibition of NF-kappaB/p65 transcriptional activity, and induction of p21/WAF-1 in a dose- and time-dependent manner. Apigenin at these doses resulted in ROS generation, which was accompanied by rapid glutathione depletion, disruption of mitochondrial membrane potential, cytosolic release of cytochrome c, and apoptosis. Interestingly, we observed accumulation of a p53 fraction to the mitochondria, which was rapid and occurred between 1 and 3 h after apigenin treatment. All these effects were significantly blocked by pretreatment of cells with the antioxidant N-acetylcysteine, p53 inhibitor pifithrin-alpha, and enzyme catalase. Apigenin-mediated p53 activation and apoptosis were further attenuated by p53 antisense oligonucleotide treatment. Exposure of cells to apigenin led to a decrease in the levels of Bcl-XL and Bcl-2 and increase in Bax, triggering caspase activation. Treatment with the caspase inhibitors Z-VAD-FMK and DEVD-CHO partially rescued these cells from apigenin-induced apoptosis. In vivo, apigenin administration demonstrated p53-mediated induction of apoptosis in 22Rv1 tumors. These results indicate that apigenin-induced apoptosis in 22Rv1 cells is initiated by a ROS-dependent disruption of the mitochondrial membrane potential through transcriptional-dependent and -independent p53 pathways.

  4. High Resolution Melting Analysis for Detecting p53 Gene Mutations in Patients with Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Zhihong CHEN

    2011-10-01

    Full Text Available Background and objective It has been proven that p53 gene was related to many human cancers. The mutations in p53 gene play an important role in carcinogensis and mostly happened in exon 5-8. The aim of this study is to establish a high resolution melting (HRM assay to detect p53 mutations from patients with non-small cell lung cancer (NSCLC, to investigate the characteristics of p53 gene mutations, and to analyze the relationship between p53 mutations and evolution regularity of pathogenesis. Methods p53 mutations in exon 5-8 were detected by HRM assay on DNA insolated from 264 NSCLC samples derived from tumor tissues and 54 control samples from pericancerous pulmonary tissues. The mutation samples by the HRM assay were confirmed by sequencing technique. Samples which were positive by HRM but wild type by sequencing were further confirmed by sub-clone and sequencing. Results No mutation was found in 54 pericancerous pulmonary samples by HRM assay. 104 of the 264 tumor tissues demonstrated mutation curves by HRM assay, 102 samples were confirmed by sequencing, including 95 point mutations and 7 frame shift mutations by insertion or deletion. The mutation rate of p53 gene was 39.4%. The mutation rate from exon 5-8 were 11.7%, 8%, 12.5% and 10.6%, respectively and there was no statistically significant difference between them (P=0.35. p53 mutations were significantly more frequent in males than that in females, but not related to the other clinicopathologic characteristics. Conclusion The results indicate that HRM is a sensitive in-tube methodology to detect for mutations in clinical samples. The results suggest that the arising p53 mutations in NSCLC may be due to spontaneous error in DNA synthesis and repair.

  5. Pharmacological reactivation of p53 as a strategy to treat cancer.

    Science.gov (United States)

    Zawacka-Pankau, J; Selivanova, G

    2015-02-01

    It has been confirmed through studies using the technique of unbiased sequencing that the TP53 tumour suppressor is the most frequently inactivated gene in cancer. This finding, together with results from earlier studies, provides compelling evidence for the idea that p53 ablation is required for the development and maintenance of tumours. Genetic reconstitution of the function of p53 leads to the suppression of established tumours as shown in mouse models. This strongly supports the notion that p53 reactivation by small molecules could provide an efficient strategy to treat cancer. In this review, we summarize recent advances in the development of small molecules that restore the function of mutant p53 by different mechanisms, including stabilization of its folding by Apr-246, which is currently being tested in a Phase II clinical trial. We discuss several classes of compounds that reactivate wild-type p53, such as Mdm2 inhibitors, which are currently undergoing clinical testing, MdmX inhibitors and molecules targeting factors upstream of Mdm2/X or p53 itself. Finally, we consider the clinical applications of compounds targeting p53 and the p53 pathway.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Homozygous mdm2 SNP309 cancer cells with compromised transcriptional elongation at p53 target genes are sensitive to induction of p53-independent cell death.

    Science.gov (United States)

    Rosso, Melissa; Polotskaia, Alla; Bargonetti, Jill

    2015-10-27

    A single nucleotide polymorphism (T to G) in the mdm2 P2 promoter, mdm2 SNP309, leads to MDM2 overexpression promoting chemotherapy resistant cancers. Two mdm2 G/G SNP309 cancer cell lines, MANCA and A875, have compromised wild-type p53 that co-localizes with MDM2 on chromatin. We hypothesized that MDM2 in these cells inhibited transcription initiation at the p53 target genes p21 and puma. Surprisingly, following etoposide treatment transcription initiation occurred at the compromised target genes in MANCA and A875 cells similar to the T/T ML-1 cell line. In all cell lines tested there was equally robust recruitment of total and initiated RNA polymerase II (Pol II). We found that knockdown of MDM2 in G/G cells moderately increased expression of subsets of p53 target genes without increasing p53 stability. Importantly, etoposide and actinomycin D treatments increased histone H3K36 trimethylation in T/T, but not G/G cells, suggesting a G/G correlated inhibition of transcription elongation. We therefore tested a chemotherapeutic agent (8-amino-adenosine) that induces p53-independent cell death for higher clinically relevant cytotoxicity. We demonstrated that T/T and G/G mdm2 SNP309 cells were equally sensitive to 8-amino-adenosine induced cell death. In conclusion for cancer cells overexpressing MDM2, targeting MDM2 may be less effective than inducing p53-independent cell death.

  8. Novel Roles for P53 in the Genesis and Targeting of Tetraploid Cancer Cells

    OpenAIRE

    Batzaya Davaadelger; Hong Shen; Maki, Carl G.

    2014-01-01

    Tetraploid (4N) cells are considered important in cancer because they can display increased tumorigenicity, resistance to conventional therapies, and are believed to be precursors to whole chromosome aneuploidy. It is therefore important to determine how tetraploid cancer cells arise, and how to target them. P53 is a tumor suppressor protein and key regulator of tetraploidy. As part of the "tetraploidy checkpoint", p53 inhibits tetraploid cell proliferation by promoting a G1-arrest in incipie...

  9. Revisiting p53 for cancer-specific chemo- and radiotherapy: ten years after.

    Science.gov (United States)

    Beckta, Jason M; Ahmad, Syed Farhan; Yang, Hu; Valerie, Kristoffer

    2014-01-01

    Despite intense studies, highly effective therapeutic strategies against cancer have not yet been fully exploited, because few true cancer-specific targets have been identified. Most modalities, perhaps with the exception of radiation therapy, target proliferating cells, which are also abundant in normal tissues. Thus, most current cancer treatments have significant side effects. More than 10 years ago, the tumor suppressor p53 was first explored as a cancer-specific target. At the time, the approach was to introduce a normal p53 gene into mutant p53 (mp53) tumor cells to induce cell cycle arrest and apoptosis. However, this strategy did not hold up and mostly failed in subsequent clinical studies. Recent research developments have now returned p53 to the limelight. Several studies have reported that mutant or null p53 tumor cells undergo apoptosis more easily than genetically matched, normal p53 counterparts when inhibiting a specific stress kinase in combination with standard chemotherapy or when exposed to an ataxia-telangiectasia mutated (ATM) kinase inhibitor and radiation, thus achieving true cancer specificity in animal tumor models. This short review highlights several of these recent studies, discusses possible mechanism(s) for mp53-mediated "synthetic lethality," and the implications for cancer therapy.

  10. Fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of LncRNA MEG3

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Duanmin [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Su, Cunjin [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Jiang, Min [Department of Breast Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shen, Yating [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shi, Aiming; Zhao, Fenglun [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Chen, Ruidong [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Shen, Zhu [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Bao, Junjie, E-mail: baojjsdfey@sina.com [Department of Pharmacy, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China); Tang, Wen, E-mail: sztangwen@163.com [Department of Gastroenterology, The Second Affiliated Hospital of Soochow University, Suzhou 215004 (China)

    2016-03-04

    There is still no suitable drug for pancreatic cancer treatment, which is one of the most aggressive human tumors. Maternally expressed gene 3 (MEG3), a LncRNA, has been suggested as a tumor suppressor in a range of human tumors. Studies found fenofibrate exerted anti-tumor roles in various human cancer cell lines. However, its role in pancreatic cancer remains unknown. The present study aimed to explore the impacts of fenofibrate on pancreatic cancer cell lines, and to investigate MEG3 role in its anti-tumor mechanisms. We used MTT assay to determine cells proliferation, genome-wide LncRNA microarray analysis to identify differently expressed LncRNAs, siRNA or pCDNA-MEG3 transfection to interfere or upregulate MEG3 expression, western blot to detect protein levels, real-time PCR to determine MEG3 level. Fenofibrate significantly inhibited proliferation of pancreatic cancer cells, increased MEG3 expression and p53 levels. Moreover, knockdown of MEG3 attenuated cytotoxicity induced by fenofibrate. Furthermore, overexpression of MEG3 induced cells death and increased p53 expression. Our results indicated fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of MEG3. - Highlights: • We found that fenofibrate suppressed proliferation of pancreatic cancer cells. • We found fenofibrate increased LncRNA-MEG3 expression and p53 level in PANC-1 cells. • Inhibition of MEG3 expression attenuated anti-tumor effects of fenofibrate.

  11. P53 mutations in colorectal cancer - molecular pathogenesis and pharmacological reactivation.

    Science.gov (United States)

    Li, Xiao-Lan; Zhou, Jianbiao; Chen, Zhi-Rong; Chng, Wee-Joo

    2015-01-07

    Colorectal cancer (CRC) is one of the most common malignancies with high prevalence and low 5-year survival. CRC is a heterogeneous disease with a complex, genetic and biochemical background. It is now generally accepted that a few important intracellular signaling pathways, including Wnt/β-catenin signaling, Ras signaling, and p53 signaling are frequently dysregulated in CRC. Patients with mutant p53 gene are often resistant to current therapies, conferring poor prognosis. Tumor suppressor p53 protein is a transcription factor inducing cell cycle arrest, senescence, and apoptosis under cellular stress. Emerging evidence from laboratories and clinical trials shows that some small molecule inhibitors exert anti-cancer effect via reactivation and restoration of p53 function. In this review, we summarize the p53 function and characterize its mutations in CRC. The involvement of p53 mutations in pathogenesis of CRC and their clinical impacts will be highlighted. Moreover, we also describe the current achievements of using p53 modulators to reactivate this pathway in CRC, which may have great potential as novel anti-cancer therapy.

  12. Comparative assessment of the apoptotic potential of silver nanoparticles synthesized by Bacillus tequilensis and Calocybe indica in MDA-MB-231 human breast cancer cells: targeting p53 for anticancer therapy

    Directory of Open Access Journals (Sweden)

    Gurunathan S

    2015-06-01

    -MB-231 breast cancer cells. Western blot analyses revealed that AgNPs induce cellular apoptosis via activation of p53, p-Erk1/2, and caspase-3 signaling, and downregulation of Bcl-2. Cells pretreated with pifithrin-alpha were protected from p53-mediated AgNPs-induced toxicity.Conclusion: We have demonstrated a simple approach for the synthesis of AgNPs using the novel strains B. tequilensis and C. indica, as well as their mechanism of cell death in a p53-dependent manner in MDA-MB-231 human breast cancer cells. The present findings could provide insight for the future development of a suitable anticancer drug, which may lead to the development of novel nanotherapeutic molecules for the treatment of cancers.Keywords: apoptosis, UV-vis spectroscopy, X-ray diffraction, ROS generation

  13. Novel roles for p53 in the genesis and targeting of tetraploid cancer cells.

    Science.gov (United States)

    Davaadelger, Batzaya; Shen, Hong; Maki, Carl G

    2014-01-01

    Tetraploid (4N) cells are considered important in cancer because they can display increased tumorigenicity, resistance to conventional therapies, and are believed to be precursors to whole chromosome aneuploidy. It is therefore important to determine how tetraploid cancer cells arise, and how to target them. P53 is a tumor suppressor protein and key regulator of tetraploidy. As part of the "tetraploidy checkpoint", p53 inhibits tetraploid cell proliferation by promoting a G1-arrest in incipient tetraploid cells (referred to as a tetraploid G1 arrest). Nutlin-3a is a preclinical drug that stabilizes p53 by blocking the interaction between p53 and MDM2. In the current study, Nutlin-3a promoted a p53-dependent tetraploid G1 arrest in two diploid clones of the HCT116 colon cancer cell line. Both clones underwent endoreduplication after Nutlin removal, giving rise to stable tetraploid clones that showed increased resistance to ionizing radiation (IR) and cisplatin (CP)-induced apoptosis compared to their diploid precursors. These findings demonstrate that transient p53 activation by Nutlin can promote tetraploid cell formation from diploid precursors, and the resulting tetraploid cells are therapy (IR/CP) resistant. Importantly, the tetraploid clones selected after Nutlin treatment expressed approximately twice as much P53 and MDM2 mRNA as diploid precursors, expressed approximately twice as many p53-MDM2 protein complexes (by co-immunoprecipitation), and were more susceptible to p53-dependent apoptosis and growth arrest induced by Nutlin. Based on these findings, we propose that p53 plays novel roles in both the formation and targeting of tetraploid cells. Specifically, we propose that 1) transient p53 activation can promote a tetraploid-G1 arrest and, as a result, may inadvertently promote formation of therapy-resistant tetraploid cells, and 2) therapy-resistant tetraploid cells, by virtue of having higher P53 gene copy number and expressing twice as many p53-MDM2

  14. Inactivation of p53 in Human Keratinocytes Leads to Squamous Differentiation and Shedding via Replication Stress and Mitotic Slippage.

    Science.gov (United States)

    Freije, Ana; Molinuevo, Rut; Ceballos, Laura; Cagigas, Marta; Alonso-Lecue, Pilar; Rodriguez, René; Menendez, Pablo; Aberdam, Daniel; De Diego, Ernesto; Gandarillas, Alberto

    2014-11-20

    Tumor suppressor p53 is a major cellular guardian of genome integrity, and its inactivation is the most frequent genetic alteration in cancer, rising up to 80% in squamous cell carcinoma (SCC). By adapting the small hairpin RNA (shRNA) technology, we inactivated endogenous p53 in primary epithelial cells from the epidermis of human skin. We show that either loss of endogenous p53 or overexpression of a temperature-sensitive dominant-negative conformation triggers a self-protective differentiation response, resulting in cell stratification and expulsion. These effects follow DNA damage and exit from mitosis without cell division. p53 preserves the proliferative potential of the stem cell compartment and limits the power of proto-oncogene MYC to drive cell cycle stress and differentiation. The results provide insight into the role of p53 in self-renewal homeostasis and help explain why p53 mutations do not initiate skin cancer but increase the likelihood that cancer cells will appear.

  15. Inactivation of p53 in Human Keratinocytes Leads to Squamous Differentiation and Shedding via Replication Stress and Mitotic Slippage

    Directory of Open Access Journals (Sweden)

    Ana Freije

    2014-11-01

    Full Text Available Tumor suppressor p53 is a major cellular guardian of genome integrity, and its inactivation is the most frequent genetic alteration in cancer, rising up to 80% in squamous cell carcinoma (SCC. By adapting the small hairpin RNA (shRNA technology, we inactivated endogenous p53 in primary epithelial cells from the epidermis of human skin. We show that either loss of endogenous p53 or overexpression of a temperature-sensitive dominant-negative conformation triggers a self-protective differentiation response, resulting in cell stratification and expulsion. These effects follow DNA damage and exit from mitosis without cell division. p53 preserves the proliferative potential of the stem cell compartment and limits the power of proto-oncogene MYC to drive cell cycle stress and differentiation. The results provide insight into the role of p53 in self-renewal homeostasis and help explain why p53 mutations do not initiate skin cancer but increase the likelihood that cancer cells will appear.

  16. [Expression of protein p53 in workers occupationally exposed to benzidine and bladder cancer patients.].

    Science.gov (United States)

    Shen, Chun-lin; Xiang, Cui-qin; Zhang, Yun-ying; Qin, Yi-qiu; Liu, Cha-qin; Chen, Ji-gang; Zhang, Sheng-nian

    2005-02-01

    To study expression of mutant p53 protein in workers occupationally exposed to benzidine and bladder cancer patients. Mutant p53 protein in serum from the workers occupationally exposed to benzidine and bladder cancer patients were determined with Immuno-PCR, while exfoliated urothelial cells in the urine samples were classified with Papanicolau grading. Positive rate of mutant p53 protein increased with the exposed intensity index in workers occupationally exposed to benzidine. The positive rate of mutant p53 protein in bladder cancer patients (83.3%) was significantly higher than that in the group 1 of exposed intensity index. The average scanning integrals of PCR amplified band in the group of bladder cancer patients and group 2 of exposed intensity index were both higher than that in the group 1 significantly. Workers in the groups of different exposed intensity indices were further stratified according to Papanicolau grades. In the group 2 of exposed intensity index, the average scanning integrals of PCR amplified band in the stratum of Papanicolau grade II and III were significantly higher than that in the strata of Papanicolau grade I. And in the group 3 of exposed intensity index, the positive rate of mutant p53 protein in the strata of Papanicolau grade III was higher than that in the strata of Papanicolau grade I significantly. The increase of exposed intensity may not only result in the positive rate of mutant p53 protein, but also the quantity of mutant p53 protein in serum within the low range of benzidine exposure. Once the exposed intensity was beyond that spectrum, the positive rate of mutant p53 protein in serum and the average scanning integrals of PCR amplified band were no longer enhanced with the increase of exposed intensity. There was tight correlation between Papanicolau grade of exfoliated urothelial cells and the positive rate or the quantity of mutant p53 protein for the higher benzidine exposure intensity.

  17. Mutant p53 drives cancer by subverting multiple tumour suppression pathways

    Directory of Open Access Journals (Sweden)

    Sue eHaupt

    2016-01-01

    Full Text Available The tumour suppressor p53 normally acts as a brake to halt damaged cells from perpetrating their genetic errors into future generations. If p53 is disrupted by mutation, it may not only lose these corrective powers, but counter-productively acquire new capacities that drive cancer. A newly emerging manner in which mutant p53 executes its cancer promoting functions is by harnessing key proteins (including many transcription factors, which normally partner with its wild type, tumour-inhibiting counterpart. In association with the subverted activities of these protein partners, mutant p53 is empowered to act across multiple fundamental cellular pathways (regulating cell division and metabolism and corrupt them to become cancer promoting.

  18. Transcriptional repression in normal human keratinocytes by wild-type and mutant p53.

    Science.gov (United States)

    Alvarez-Salas, L M; Velazquez, A; Lopez-Bayghen, E; Woodworth, C D; Garrido, E; Gariglio, P; DiPaolo, J A

    1995-05-01

    Wild-type p53 is a nuclear phosphoprotein that inhibits cell proliferation and represses transcriptionally most TATA box-containing promoters in transformed or tumor-derived cell lines. This study demonstrates that p53 alters transcription of the long control region (LCR) of human papillomavirus type 18 (HPV-18). Wild-type and mutant p53 143Val to Ala repressed the HPV-18 LCR promoter in normal human keratinocytes, the natural host cell for HPV infections. Repression by wild-type p53 was also observed in C-33A cells and in an HPV-16-immortalized cell line with an inducible wild-type p53. However, when C-33A cells were cotransfected with the HPV-18 LCR and mutant 143Val to Ala, repression did not occur. Mutant p53 135Cys to Ser did not induce repression in either normal human keratinocytes or in the C-33A line; although like 143Val to Ala, it is thought to affect the DNA binding activity of the wild-type protein. The ability of mutant p53 143Val to Ala to inactivate the HPV early promoter in normal cells (by approximately 60% reduction) suggests that this mutant may be able to associate with wild-type p53 and interact with TATA box-binding proteins. Therefore, these results demonstrate that the transcriptional activities of p53 mutants may be dependent upon the cell type assayed and the form of its endogenous p53. Furthermore, normal human keratinocytes represent an alternative model for determining the activities of p53 mutants.

  19. p53 family members - important messengers in cell death signaling in photodynamic therapy of cancer?

    Science.gov (United States)

    Acedo, Pilar; Zawacka-Pankau, Joanna

    2015-08-01

    TP53 is one of the genes most frequently inactivated in cancers. Mutations in TP53 gene are linked to worse prognosis and shorter overall survival of cancer patients. TP53 encodes a critical tumor suppressor, which dictates cell fate decisions upon stress stimuli. As a sensor of cellular stress, p53 is a relevant messenger of cell death signaling in ROS-driven photodynamic therapy (PDT) of cancer. The significant role of p53 in response to PDT has been reported for several clinically approved photosensitizers. Multiple reports described that wild-type p53 contributes to cell killing upon photodynamic therapy with clinically approved photosensitizers but the mechanism is still not fully understood. This work outlines the diverse functions of p53 family members in cancer cells' susceptibility and resistance to PDT. In summary p53 and p53 family members are emerging as important mediators of cell death signaling in photodynamic therapy of cancer, however the mechanism of cell death provoked during PDT might differ depending on the tissue type and the photosensitizer applied.

  20. SIRT1 inhibition restores apoptotic sensitivity in p53-mutated human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Herbert, Katharine J.; Cook, Anthony L., E-mail: Anthony.Cook@utas.edu.au; Snow, Elizabeth T., E-mail: elizabeth.snow@utas.edu.au

    2014-06-15

    Mutations to the p53 gene are common in UV-exposed keratinocytes and contribute to apoptotic resistance in skin cancer. P53-dependent activity is modulated, in part, by a complex, self-limiting feedback loop imposed by miR-34a-mediated regulation of the lysine deacetylase, SIRT1. Expression of numerous microRNAs is dysregulated in squamous and basal cell carcinomas; however the contribution of specific microRNAs to the pathogenesis of skin cancer remains untested. Through use of RNAi, miRNA target site blocking oligonucleotides and small molecule inhibitors, this study explored the influence of p53 mutational status, SIRT1 activity and miR-34a levels on apoptotic sensitivity in primary (NHEK) and p53-mutated (HaCaT) keratinocyte cell lines. SIRT1 and p53 are overexpressed in p53-mutated keratinocytes, whilst miR-34a levels are 90% less in HaCaT cells. HaCaTs have impaired responses to p53/SIRT1/miR-34a axis manipulation which enhanced survival during exposure to the chemotherapeutic agent, camptothecin. Inhibition of SIRT1 activity in this cell line increased p53 acetylation and doubled camptothecin-induced cell death. Our results demonstrate that p53 mutations increase apoptotic resistance in keratinocytes by interfering with miR-34a-mediated regulation of SIRT1 expression. Thus, SIRT1 inhibitors may have a therapeutic potential for overcoming apoptotic resistance during skin cancer treatment. - Highlights: • Impaired microRNA biogenesis promotes apoptotic resistance in HaCaT keratinocytes. • TP53 mutations suppress miR-34a-mediated regulation of SIRT1 expression. • SIRT1 inhibition increases p53 acetylation in HaCaTs, restoring apoptosis.

  1. Regulation of Human p53 Activity and Cell Localization by Alternative Splicing

    OpenAIRE

    2004-01-01

    The development of cancer is a multistep process involving mutations in proto-oncogenes, tumor suppressor genes, and other genes which control cell proliferation, telomere stability, angiogenesis, and other complex traits. Despite this complexity, the cellular pathways controlled by the p53 tumor suppressor protein are compromised in most, if not all, cancers. In normal cells, p53 controls cell proliferation, senescence, and/or mediates apoptosis in response to stress, cell damage, or ectopic...

  2. p53-mediated autophagic regulation: A prospective strategy for cancer therapy.

    Science.gov (United States)

    Tang, Juanjuan; Di, Jiehui; Cao, Huan; Bai, Jin; Zheng, Junnian

    2015-07-28

    Autophagy is a major catabolic process that degrades and recycles cytosolic components in autophagosomes, which fuse with lysosomes. This process enables starving cells to sustain their energy requirements and metabolic states, thus facilitating their survival, especially in cancer pathogenesis. The regulation of autophagy is quite intricate. It involves a series of signaling cascades including p53, known as the best-characterized tumor suppressor protein. Recent reports have indicated that p53 plays dual roles in regulating autophagy depending on its subcellular localization. Nuclear p53 facilitates autophagy by transactivating its target genes, whereas cytoplasmic p53 mainly inhibits autophagy through extranuclear, transcription-independent mechanisms. The relationship between autophagy and neoplasia is complicated. It may be intrinsically associated with the functional status of p53, but this is not clearly elucidated. This review focuses on the role of p53 as a master regulator of autophagy. We conclude that the contextual role of autophagy in cancer, which could be switched by p53 status, is expected to be developed into a new anticancer therapeutic approach.

  3. Clonal dynamics following p53 loss of heterozygosity in Kras-driven cancers

    Science.gov (United States)

    Muzumdar, Mandar Deepak; Dorans, Kimberly Judith; Chung, Katherine Minjee; Robbins, Rebecca; Tammela, Tuomas; Gocheva, Vasilena; Li, Carman Man-Chung; Jacks, Tyler

    2016-01-01

    Although it has become increasingly clear that cancers display extensive cellular heterogeneity, the spatial growth dynamics of genetically distinct clones within developing solid tumours remain poorly understood. Here we leverage mosaic analysis with double markers (MADM) to trace subclonal populations retaining or lacking p53 within oncogenic Kras-initiated lung and pancreatic tumours. In both models, p53 constrains progression to advanced adenocarcinomas. Comparison of lineage-related p53 knockout and wild-type clones reveals a minor role of p53 in suppressing cell expansion in lung adenomas. In contrast, p53 loss promotes both the initiation and expansion of low-grade pancreatic intraepithelial neoplasia (PanINs), likely through differential expression of the p53 regulator p19ARF. Strikingly, lineage-related cells are often dispersed in lung adenomas and PanINs, contrasting with more contiguous growth of advanced subclones. Together, these results support cancer type-specific suppressive roles of p53 in early tumour progression and offer insights into clonal growth patterns during tumour development. PMID:27585860

  4. The Prognostic Value of UHRF-1 and p53 in Gastric Cancer

    Science.gov (United States)

    Babacan, Nalan A.; Eğilmez, Hatice Reyhan; Yücel, Birsen; Parlak, Ilknur; Şeker, Mehmet Metin; Kaçan, Turgut; Bahçeci, Aykut; Cihan, Sener; Akinci, Bülent; Eriten, Berna; Kılıçkap, Saadettin

    2016-01-01

    Background/Aims: This study aimed to examine whether UHRF-1 and p53 overexpression is a prognostic marker for gastric cancer. Patients and Methods: Sixty-four patients with gastric cancer (study group) and 23 patients with gastritis (control group) were evaluated. Immunohistochemistry was used to examine expression of UHRF-1 and p53 in gastric cancers and a control group diagnosed with gastritis. Results: The median age was 63 years (18-83 years) in the study group. UHRF-1 was positive in 15 (23%) patients with gastric cancer and five (21.7%) patients with gastritis (P = 0.559). UHRF1 expression level in gastric cancer is more powerful than in gastritis (P = 0.046). Thirty-seven (61%) patients with gastric cancer and only one patient with gastritis were p53 positive (P < 0.001). After a median follow-up of 12 months (1–110), the 2-year overall survival rates were 55% and 30% in negative and positive p53, respectively (P = 0.084). Also, the 2-year overall survival rates were 45% and 53% in negative and positive UHRF-1, respectively (P = 0.132). Conclusion: According to this study, UHRF-1and p53 were not prognostic factors for gastric cancer, whereas they may have a diagnostic value for differantiating between gastric cancer and gastritis. PMID:26831603

  5. The prognostic value of UHRF-1 and p53 in gastric cancer

    Directory of Open Access Journals (Sweden)

    Nalan A Babacan

    2016-01-01

    Full Text Available Background/Aims: This study aimed to examine whether UHRF-1 and p53 overexpression is a prognostic marker for gastric cancer. Patients and Methods: Sixty-four patients with gastric cancer (study group and 23 patients with gastritis (control group were evaluated. Immunohistochemistry was used to examine expression of UHRF-1 and p53 in gastric cancers and a control group diagnosed with gastritis. Results: The median age was 63 years (18-83 years in the study group. UHRF-1 was positive in 15 (23% patients with gastric cancer and fi ve (21.7% patients with gastritis (P = 0.559. UHRF1 expression level in gastric cancer is more powerful than in gastritis (P = 0.046. Thirty-seven (61% patients with gastric cancer and only one patient with gastritis were p53 positive (P < 0.001. After a median follow-up of 12 months (1-110, the 2-year overall survival rates were 55% and 30% in negative and positive p53, respectively (P = 0.084. Also, the 2-year overall survival rates were 45% and 53% in negative and positive UHRF-1, respectively (P = 0.132. Conclusion: According to this study, UHRF-1and p53 were not prognostic factors for gastric cancer, whereas they may have a diagnostic value for differantiating between gastric cancer and gastritis.

  6. HOP expression is regulated by p53 and RAS and characteristic of a cancer gene signature.

    Science.gov (United States)

    Mattison, Stacey A; Blatch, Gregory L; Edkins, Adrienne L

    2017-03-01

    The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.

  7. Mutant p53 and mTOR/PKM2 regulation in cancer cells.

    Science.gov (United States)

    Dando, Ilaria; Cordani, Marco; Donadelli, Massimo

    2016-09-01

    Mutations of TP53 gene are the most common feature in aggressive malignant cells. In addition to the loss of the tumor suppressive role of wild-type p53, hotspot mutant p53 isoforms display oncogenic proprieties notoriously referred as gain of functions (GOFs) which result in chemoresistance to therapies, genomic instability, aberrant deregulation of cell cycle progression, invasiveness and enhanced metastatic potential, and finally, in patient poor survival rate. The identification of novel functional oncogenic pathways regulated by mutant p53 represent and intriguing topic for emerging therapies against a broad spectrum of cancer types bearing mutant TP53 gene. Mammalian target of rapamycin (mTOR), as well as pyruvate kinase isoform M2 (PKM2) are master regulators of cancer growth, metabolism, and cell proliferation. Herein, we report that GOF mutant R175H and R273H p53 proteins trigger PKM2 phosphorylation on Tyr 105 through the involvement of mTOR signaling. Our data, together with the newly discovered connection between mutant p53 and mTOR stimulation, raise important implications for the potential therapeutic use of synthetic drugs inhibiting mTOR/PKM2 axis in cancer cells bearing mutant TP53 gene. We further hypothesize that mTOR/PKM2 pathway stimulation serves to sustain the oncogenic activity of mutant p53 through both the enhancement of chemoresistance and of aerobic glycolysis of cancer cells. © 2016 IUBMB Life, 68(9):722-726, 2016.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  9. The incidence of p53 mutations increases with progression of head and neck cancer.

    Science.gov (United States)

    Boyle, J O; Hakim, J; Koch, W; van der Riet, P; Hruban, R H; Roa, R A; Correo, R; Eby, Y J; Ruppert, J M; Sidransky, D

    1993-10-01

    To establish a genetic model of the progression of head and neck squamous carcinoma we have defined the incidence and timing of p53 mutations in this type of cancer. We sequenced the conserved regions of the p53 gene in 102 head and neck squamous carcinoma lesions. These included 65 primary invasive carcinomas and 37 noninvasive archival specimens consisting of 13 severe dysplasias and 24 carcinoma in situ lesions. The incidence of p53 mutations in noninvasive lesions was 19% (7/37) and increased to 43% (28/65) in invasive carcinomas. These data suggest that p53 mutations can precede invasion in primary head and neck cancer. Furthermore, the spectrum of codon hotspots is similar to that seen in squamous carcinoma of the lung and 64% of mutations are at G nucleotides, implicating carcinogens from tobacco smoke in the etiology of head and neck squamous carcinoma.

  10. Analytical Validation of AmpliChip p53 Research Test for Archival Human Ovarian FFPE Sections.

    Science.gov (United States)

    Marton, Matthew J; McNamara, Andrew R; Nikoloff, D Michele; Nakao, Aki; Cheng, Jonathan

    2015-01-01

    The p53 tumor suppressor gene (TP53) is reported to be mutated in nearly half of all tumors and plays a central role in genome integrity. Detection of mutations in p53 can be accomplished by many assays, including the AmpliChip p53 Research Test. The AmpliChip p53 Research Test has been successfully used to determine p53 status in hematologic malignancies and fresh frozen solid tissues but there are few reports of using the assay with formalin fixed, paraffin-embedded (FFPE) tissue. The objective of this study was to describe analytical performance characterization of the AmpliChip p53 Research Test to detect p53 mutations in genomic DNA isolated from archival FFPE human ovarian tumor tissues. Method correlation with sequencing showed 96% mutation-wise agreement and 99% chip-wise agreement. We furthermore observed 100% agreement (113/113) of the most prevalent TP53 mutations. Workflow reproducibility was 96.8% across 8 samples, with 2 operators, 2 reagent lots and 2 instruments. Section-to-section reproducibility was 100% for each sample across a 60 μm region of the FFPE block from ovarian tumors. These data indicate that the AmpliChip p53 Research Test is an accurate and reproducible method for detecting mutations in TP53 from archival FFPE human ovarian specimens.

  11. Analytical Validation of AmpliChip p53 Research Test for Archival Human Ovarian FFPE Sections.

    Directory of Open Access Journals (Sweden)

    Matthew J Marton

    Full Text Available The p53 tumor suppressor gene (TP53 is reported to be mutated in nearly half of all tumors and plays a central role in genome integrity. Detection of mutations in p53 can be accomplished by many assays, including the AmpliChip p53 Research Test. The AmpliChip p53 Research Test has been successfully used to determine p53 status in hematologic malignancies and fresh frozen solid tissues but there are few reports of using the assay with formalin fixed, paraffin-embedded (FFPE tissue. The objective of this study was to describe analytical performance characterization of the AmpliChip p53 Research Test to detect p53 mutations in genomic DNA isolated from archival FFPE human ovarian tumor tissues. Method correlation with sequencing showed 96% mutation-wise agreement and 99% chip-wise agreement. We furthermore observed 100% agreement (113/113 of the most prevalent TP53 mutations. Workflow reproducibility was 96.8% across 8 samples, with 2 operators, 2 reagent lots and 2 instruments. Section-to-section reproducibility was 100% for each sample across a 60 μm region of the FFPE block from ovarian tumors. These data indicate that the AmpliChip p53 Research Test is an accurate and reproducible method for detecting mutations in TP53 from archival FFPE human ovarian specimens.

  12. Quantitative evaluation of p53 as a new indicator of DNA damage in human spermatozoa

    Directory of Open Access Journals (Sweden)

    Salvatore Raimondo

    2014-01-01

    The aim of this study was to assess if a p53 ELISA assay could be a new indicator of DNA damage in human spermatozoa. Materials and Methods: 103 human semen samples were evaluated using both Acridine Orange test and p53 ELISA and results were compared. Results: A clear correlation between the values measured by two methods was obtained. Conclusions: If this hypothesis will be confirmed by further studies, the p53 ELISA assay could become a new and more precise indicator of DNA damage in human spermatozoa.

  13. Correlation of survivin, p53 and Ki-67 in laryngeal cancer Hep-2 cell proliferation and invasion.

    Science.gov (United States)

    Pei, Shi-Geng; Wang, Ju-Xiang; Wang, Xue-Ling; Zhang, Qing-Jun; Zhang, Hong

    2015-08-01

    To investigate the mechanism of survivin, p53 and Ki-67 on Hep-2 human laryngeal cancer endothelial cell proliferation and invasion. Laryngeal squamous cell carcinoma and paracancerous normal tissues were collected, total RNA was extracted from tissues, survivin, p53 and Ki-67 gene mRNA expression levels in laryngeal cancer and the adjacent tissues were detected by Real-time PCR. Human laryngeal cancer Hep-2 epithelial cells were selected, survivin gene was overexpressed, and cell proliferation was detected by MTT. p53 and Ki-67 gene expression changes in overexpressed survivin gene were detected by Western blot. Changes in Hep-2 cell invasive ability were studied when survivin was overexpressed as detected by Transwell invasion assay. In the adjacent tissues, survivin, p53 and Ki-67 gene relative expression levels were 1.72 ± 0.9, 13.7 ± 5.7 and 5.7 ± 1.3, respectively; while in cancer tissues, gene relative expression levels were 53.7 ± 8.3, 66.7 ± 5.2 and 61.0 ± 3.1, respectively, which was significantly increased. As detected by MTT, relative cell survival rate within 12 h of survivin overexpression were: load control group (88.5 ± 1.6)%; overexpressed group (90.3 ± 1.9)%. Transwell invasion assay results indicated that overexpressed survivin could significantly increase the relative survival rate of cells. Expressions of p53, Ki67 and survivin are increased in cancer; and there is a positive correlation between survivin, p53 and Ki67 expressions in laryngeal carcinoma. Copyright © 2015 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

  14. Combining intracellular antibodies to restore function of mutated p53 in cancer.

    Science.gov (United States)

    Chan, Grace; Jordaan, Gwen; Nishimura, Robert N; Weisbart, Richard H

    2016-01-01

    TP53 is a tumor suppressor gene that is mutated in 50% of cancers, and its function is tightly regulated by the E3 ligase, Mdm2. Both p53 and Mdm2 are localized in the cell nucleus, a site that is impervious to therapeutic regulation by most antibodies. We identified a cell-penetrating lupus monoclonal anti-DNA antibody, mAb 3E10, that targets the nucleus, and we engineered mAb 3E10 to function as an intranuclear transport system to deliver therapeutic antibodies into the nucleus as bispecific single chain Fv (scFv) fragments. Bispecific scFvs composed of 3E10 include PAb421 (3E10-PAb421) that binds p53 and restores the function of mutated p53, and 3G5 (3E10-3G5) that binds Mdm2 and prevents destruction of p53 by Mdm2. We documented the therapeutic efficacy of these bispecific scFvs separately in previous studies. In this study, we show that combination therapy with 3E10-PAb421 and 3E10-3G5 augments growth inhibition of cells with p53 mutations compared to the effect of either antibody alone. By contrast, no enhanced response was observed in cells with wild-type p53 or in cells homozygous null for p53.

  15. The p53-reactivating small molecule RITA induces senescence in head and neck cancer cells.

    Directory of Open Access Journals (Sweden)

    Hui-Ching Chuang

    Full Text Available TP53 is the most commonly mutated gene in head and neck cancer (HNSCC, with mutations being associated with resistance to conventional therapy. Restoring normal p53 function has previously been investigated via the use of RITA (reactivation of p53 and induction of tumor cell apoptosis, a small molecule that induces a conformational change in p53, leading to activation of its downstream targets. In the current study we found that RITA indeed exerts significant effects in HNSCC cells. However, in this model, we found that a significant outcome of RITA treatment was accelerated senescence. RITA-induced senescence in a variety of p53 backgrounds, including p53 null cells. Also, inhibition of p53 expression did not appear to significantly inhibit RITA-induced senescence. Thus, this phenomenon appears to be partially p53-independent. Additionally, RITA-induced senescence appears to be partially mediated by activation of the DNA damage response and SIRT1 (Silent information regulator T1 inhibition, with a synergistic effect seen by combining either ionizing radiation or SIRT1 inhibition with RITA treatment. These data point toward a novel mechanism of RITA function as well as hint to its possible therapeutic benefit in HNSCC.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  17. P53 GENE MUTATIONS IN NON-SMALL CELL LUNG CANCER DETECTED BY POLYMERASE CHAIN REACTION SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    赵永良; 吴德昌; 项晓琼; 张宝仁; 周乃康; 胡迎春

    1999-01-01

    Mutations of the p53 tumor suppressor gone are the most frequent genetic akerations detected in human lung cancer. To assess the pathogenic significance of p53 gone alterations in Chlnege non-small cell lung cancer (NSCLC), 74 paired samples of primary lung cancer and normal lung tissue far away from the cancer were analyzed for mutations of the p53 gene(exons 5-8) using exon-specific PCR, single-gtrand conformation polymorphimax (PCR-SSCP). p53 mutations were observed in 55.4% (41/74) of the samples.No linkaiges were detected between the incidence of p53 mutations and histological type, lymph node metastasis, age or sex. Significant association between p53 mutations and degree of differentiation in edenotmremmnas, not in squamous cell carcinomas, was observed, The frequency of p53 mutations in(65. 3%) was higher than in nonsmokers (33. 3%) and reached stafisrical significance. We also found p53 mutations in 6/7 samples which had tissue invasion and distant metastasis. These results suggest that smcking could be an important factor in lung carcinogenesis, p53 mutation is a worse prognosis indicator in ade and nocarcinomas and related to high aggressive behavior of human lung cancer.

  18. P53 GENE MUTATIONS IN NON-SMALL CELL LUNG CANCER DETECTED BY POLYMERASE CHAIN REACTION SINGLE-STRAND CONFORMATION POLYMORPHISM ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    @@ Mutations of the p53 tumor suppressor gene are the most frequent genetic alterations detected in human lung cancer. To assess the pathogenic significance of p53 gene alterations in Chinese non-small cell lung cancer(NSCLC),74 paired samples of primary lung cancer and normal lung tissue far away from the cancer were analyzed for mutations of the p53 gene(exons 5-8) using exon-specific PCR, single-strand conformation polymorphism (PCR-SSCP). p53 mutations were observed in 55.4%(41/74) of the samples. No linkages were detected between the incidence of p53 mutations and histological type, lymph node metastasis,age or sex. Significant association between p53 mutations and degree of differentiation in adenocarcinomas, not in squamous cell carcinomas, was observed. The frequency of p53 mutations in smokers(65.3%) was higher than in nonsmokers(33.3%) and reached statistical significance.We also found p53 mutations in 6/7 samples which had tissue invasion and distant metastasis.These results suggest that smoking could be an important factor in lung carcinogenesis,p53 mutation is a worse prognosis indicator in adenocarcinomas and related to high aggressive behavior of human lung cancer.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  20. Divergent evolution of human p53 binding sites: cell cycle versus apoptosis.

    Directory of Open Access Journals (Sweden)

    Monica M Horvath

    2007-07-01

    Full Text Available The p53 tumor suppressor is a sequence-specific pleiotropic transcription factor that coordinates cellular responses to DNA damage and stress, initiating cell-cycle arrest or triggering apoptosis. Although the human p53 binding site sequence (or response element [RE] is well characterized, some genes have consensus-poor REs that are nevertheless both necessary and sufficient for transactivation by p53. Identification of new functional gene regulatory elements under these conditions is problematic, and evolutionary conservation is often employed. We evaluated the comparative genomics approach for assessing evolutionary conservation of putative binding sites by examining conservation of 83 experimentally validated human p53 REs against mouse, rat, rabbit, and dog genomes and detected pronounced conservation differences among p53 REs and p53-regulated pathways. Bona fide NRF2 (nuclear factor [erythroid-derived 2]-like 2 nuclear factor and NFkappaB (nuclear factor of kappa light chain gene enhancer in B cells binding sites, which direct oxidative stress and innate immunity responses, were used as controls, and both exhibited high interspecific conservation. Surprisingly, the average p53 RE was not significantly more conserved than background genomic sequence, and p53 REs in apoptosis genes as a group showed very little conservation. The common bioinformatics practice of filtering RE predictions by 80% rodent sequence identity would not only give a false positive rate of approximately 19%, but miss up to 57% of true p53 REs. Examination of interspecific DNA base substitutions as a function of position in the p53 consensus sequence reveals an unexpected excess of diversity in apoptosis-regulating REs versus cell-cycle controlling REs (rodent comparisons: p < 1.0 e-12. While some p53 REs show relatively high levels of conservation, REs in many genes such as BAX, FAS, PCNA, CASP6, SIVA1, and P53AIP1 show little if any homology to rodent sequences. This

  1. MDM4 is a rational target for treating breast cancers with mutant p53.

    Science.gov (United States)

    Miranda, Panimaya Jeffreena; Buckley, Daniel; Raghu, Dinesh; Pang, Jia-Min B; Takano, Elena A; Vijayakumaran, Reshma; Teunisse, Amina Fas; Posner, Atara; Procter, Tahlia; Herold, Marco J; Gamell, Cristina; Marine, Jean-Christophe; Fox, Stephen B; Jochemsen, Aart; Haupt, Sue; Haupt, Ygal

    2017-04-01

    Mutation of the key tumour suppressor p53 defines a transition in the progression towards aggressive and metastatic breast cancer (BC) with the poorest outcome. Specifically, the p53 mutation frequency exceeds 50% in triple-negative BC. Key regulators of mutant p53 that facilitate its oncogenic functions are potential therapeutic targets. We report here that the MDM4 protein is frequently abundant in the context of mutant p53 in basal-like BC samples. Importantly, we show that MDM4 plays a critical role in the proliferation of these BC cells. We demonstrate that conditional knockdown (KD) of MDM4 provokes growth inhibition across a range of BC subtypes with mutant p53, including luminal, Her2(+) and triple-negative BCs. In vivo, MDM4 was shown to be crucial for the establishment and progression of tumours. This growth inhibition was mediated, at least in part, by the cell cycle inhibitor p27. Depletion of p27 together with MDM4 KD led to recovery of the proliferative capacity of cells that were growth-inhibited by MDM4 KD alone. Consistently, we identified low levels of p27 expression in basal-like tumours corresponding to high levels of MDM4 and p53. This predicts a signature for a subset of tumours that may be amenable to therapies targeted towards MDM4 and mutant p53. The therapeutic potential of MDM4 as a target in BC with mutant p53 was shown in vitro by use of a small-molecule inhibitor. Overall, our study supports MDM4 as a novel therapeutic target for BC expressing mutant p53. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  2. Household income is associated with the p53 mutation frequency in human breast tumors.

    Directory of Open Access Journals (Sweden)

    Adrienne M Starks

    Full Text Available BACKGROUND: A study from Scotland reported that the p53 mutation frequency in breast tumors is associated with socio-economic deprivation. METHODS: We analyzed the association of the tumor p53 mutational status with tumor characteristics, education, and self-reported annual household income (HI among 173 breast cancer patients from the greater Baltimore area, United States. RESULTS: p53 mutational frequency was significantly associated with HI. Patients with < $15,000 HI had the highest p53 mutation frequency (21%, followed by the income group between $15,000 and $60,000 (18%, while those above $60,000 HI had the fewest mutations (5%. When dichotomized at $60,000, 26 out of 135 patients in the low income category had acquired a p53 mutation, while only 2 out of 38 with a high income carried a mutation (P < 0.05. In the adjusted logistic regression analysis with 3 income categories (trend test, the association between HI and p53 mutational status was independent of tumor characteristics, age, race/ethnicity, tobacco smoking and body mass. Further analyses revealed that HI may impact the p53 mutational frequency preferentially in patients who develop an estrogen receptor (ER-negative disease. Within this group, 42% of the low income patients (< $15,000 HI carried a mutation, followed by the middle income group (21%, while those above $60,000 HI did not carry mutations (Ptrend < 0.05. CONCLUSIONS: HI is associated with the p53 mutational frequency in patients who develop an ER-negative disease. Furthermore, high income patients may acquire fewer p53 mutations than other patients, suggesting that lifetime exposures associated with socio-economic status may impact breast cancer biology.

  3. Clinical utility of anti-p53 auto-antibody: systematic review and focus on colorectal cancer.

    Science.gov (United States)

    Suppiah, Aravind; Greenman, John

    2013-08-07

    Mutation of the p53 gene is a key event in the carcinogenesis of many different types of tumours. These can occur throughout the length of the p53 gene. Anti-p53 auto-antibodies are commonly produced in response to these p53 mutations. This review firstly describes the various mechanisms of p53 dysfunction and their association with subsequent carcinogenesis. Following this, the mechanisms of induction of anti-p53 auto-antibody production are shown, with various hypotheses for the discrepancies between the presence of p53 mutation and the presence/absence of anti-p53 auto-antibodies. A systematic review was performed with a descriptive summary of key findings of each anti-p53 auto-antibody study in all cancers published in the last 30 years. Using this, the cumulative frequency of anti-p53 auto-antibody in each cancer type is calculated and then compared with the incidence of p53 mutation in each cancer to provide the largest sample calculation and correlation between mutation and anti-p53 auto-antibody published to date. Finally, the review focuses on the data of anti-p53 auto-antibody in colorectal cancer studies, and discusses future strategies including the potentially promising role using anti-p53 auto-antibody presence in screening and surveillance.

  4. Influence of zinc deficiency on AKT-MDM2-P53 signaling axes in normal and malignant human prostate cells

    Science.gov (United States)

    With prostate being the highest zinc-accumulating tissue before the onset of cancer, the effects of physiologic levels of zinc on Akt-Mdm2-p53 and Akt-p21 signaling axes in human normal prostate epithelial cells (PrEC) and malignant prostate LNCaP cells were examined. Cells were cultured for 6 d in...

  5. The early response of p53-dependent proteins during radiotherapy in human rectal carcinoma and in adjacent normal tissue

    NARCIS (Netherlands)

    Stift, A; Prager, G; Selzer, E; Widder, J; Kandioler, D; Friedl, J; Teleky, B; Herbst, F; Wrba, F; Bergmann, M

    2003-01-01

    The aim of this study was to investigate the activation of the p53 pathway and the induction of apoptosis during preoperative radiotherapy in normal human rectal tissue and in rectal carcinoma. Twelve patients with rectal cancer of the lower third were enrolled in this study. Tumor specimens and adj

  6. The Toll-like receptor gene family is integrated into human DNA damage and p53 networks.

    Directory of Open Access Journals (Sweden)

    Daniel Menendez

    2011-03-01

    Full Text Available In recent years the functions that the p53 tumor suppressor plays in human biology have been greatly extended beyond "guardian of the genome." Our studies of promoter response element sequences targeted by the p53 master regulatory transcription factor suggest a general role for this DNA damage and stress-responsive regulator in the control of human Toll-like receptor (TLR gene expression. The TLR gene family mediates innate immunity to a wide variety of pathogenic threats through recognition of conserved pathogen-associated molecular motifs. Using primary human immune cells, we have examined expression of the entire TLR gene family following exposure to anti-cancer agents that induce the p53 network. Expression of all TLR genes, TLR1 to TLR10, in blood lymphocytes and alveolar macrophages from healthy volunteers can be induced by DNA metabolic stressors. However, there is considerable inter-individual variability. Most of the TLR genes respond to p53 via canonical as well as noncanonical promoter binding sites. Importantly, the integration of the TLR gene family into the p53 network is unique to primates, a recurrent theme raised for other gene families in our previous studies. Furthermore, a polymorphism in a TLR8 response element provides the first human example of a p53 target sequence specifically responsible for endogenous gene induction. These findings-demonstrating that the human innate immune system, including downstream induction of cytokines, can be modulated by DNA metabolic stress-have many implications for health and disease, as well as for understanding the evolution of damage and p53 responsive networks.

  7. The Toll-like receptor gene family is integrated into human DNA damage and p53 networks.

    Directory of Open Access Journals (Sweden)

    Daniel Menendez

    2011-03-01

    Full Text Available In recent years the functions that the p53 tumor suppressor plays in human biology have been greatly extended beyond "guardian of the genome." Our studies of promoter response element sequences targeted by the p53 master regulatory transcription factor suggest a general role for this DNA damage and stress-responsive regulator in the control of human Toll-like receptor (TLR gene expression. The TLR gene family mediates innate immunity to a wide variety of pathogenic threats through recognition of conserved pathogen-associated molecular motifs. Using primary human immune cells, we have examined expression of the entire TLR gene family following exposure to anti-cancer agents that induce the p53 network. Expression of all TLR genes, TLR1 to TLR10, in blood lymphocytes and alveolar macrophages from healthy volunteers can be induced by DNA metabolic stressors. However, there is considerable inter-individual variability. Most of the TLR genes respond to p53 via canonical as well as noncanonical promoter binding sites. Importantly, the integration of the TLR gene family into the p53 network is unique to primates, a recurrent theme raised for other gene families in our previous studies. Furthermore, a polymorphism in a TLR8 response element provides the first human example of a p53 target sequence specifically responsible for endogenous gene induction. These findings-demonstrating that the human innate immune system, including downstream induction of cytokines, can be modulated by DNA metabolic stress-have many implications for health and disease, as well as for understanding the evolution of damage and p53 responsive networks.

  8. Berberine induces p53-dependent cell cycle arrest and apoptosis of human osteosarcoma cells by inflicting DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zhaojian; Liu Qiao; Xu Bing; Wu Jingjing [Key Laboratory of Experimental Teratology of Ministry of Education and Institute of Molecular Medicine and Genetics, Shandong University School of Medicine, Jinan, Shandong 250012 (China); Guo Chun; Zhu Faliang [Institute of Immunology, Shandong University School of Medicine, Jinan, Shandong 250012 (China); Yang Qiaozi [Department of Genetics, Rutgers University, Piscataway, NJ 08854 (United States); Gao Guimin [Key Laboratory of Experimental Teratology of Ministry of Education and Institute of Molecular Medicine and Genetics, Shandong University School of Medicine, Jinan, Shandong 250012 (China); Gong Yaoqin [Key Laboratory of Experimental Teratology of Ministry of Education and Institute of Molecular Medicine and Genetics, Shandong University School of Medicine, Jinan, Shandong 250012 (China)], E-mail: yxg8@sdu.edu.cn; Shao Changshun [Key Laboratory of Experimental Teratology of Ministry of Education and Institute of Molecular Medicine and Genetics, Shandong University School of Medicine, Jinan, Shandong 250012 (China); Department of Genetics, Rutgers University, Piscataway, NJ 08854 (United States)], E-mail: shao@biology.rutgers.edu

    2009-03-09

    Alkaloid berberine is widely used for the treatment of diarrhea and other diseases. Many laboratory studies showed that it exhibits anti-proliferative activity against a wide spectrum of cancer cells in culture. In this report we studied the mechanisms underlying the inhibitory effects of berberine on human osteosarcoma cells and on normal osteoblasts. The inhibition was largely attributed to cell cycle arrest at G1 and G2/M, and to a less extent, to apoptosis. The G1 arrest was dependent on p53, as G1 arrest was abolished in p53-deficient osteosarcoma cells. The induction of G1 arrest and apoptosis was accompanied by a p53-dependent up-regulation of p21 and pro-apoptotic genes. However, the G2/M arrest could be induced by berberine regardless of the status of p53. Interestingly, DNA double-strand breaks, as measured by the phosphorylation of H2AX, were remarkably accumulated in berberine-treated cells in a dose-dependent manner. Thus, one major mechanism by which berberine exerts its growth-inhibitory effect is to inflict genomic lesions on cells, which in turn trigger the activation of p53 and the p53-dependent cellular responses including cell cycle arrest and apoptosis.

  9. Effects of Selenium Dioxide on Apoptosis, Bcl-2 and P53 Expression, Intracellular Reactive Oxygen Species and Calcium Level in Three Human Lung Cancer Cell Lines%SeO2诱导肺癌细胞凋亡中Bcl-2和P53表达及细胞内活性氧和Ca2+水平影响的研究

    Institute of Scientific and Technical Information of China (English)

    魏亚明; WEI Yaming; 于海建; YU Haijian; 赵熙妍; ZHAO Xiyan; BAI Hai

    2004-01-01

    Objective: To evaluate the anti-tumor effects of SeO2 and its mechanisms on three human lung cancer cell lines. Methods: Three lung cancer cells A549, GLC-82 and PG were treated with 3-30μmol/L SeO2. Flow cytometry was used to detect apoptosis, and analyze the changes of expression of p53 and Bcl-2, as well as ROS and Ca2+ level within cells. Results.SeO2 markedly inhibited cell proliferation and viability, and prompted apoptosis after 48 h treatment. SeO2 at 10 μmol/L induced 47.8% apoptosis in A549 cells, 40.8% in GLC-82 cells, 18.2% in PG cells. SeO2 at 30μmol/L induced 37.8% apoposis in PG cells,but did not increase apoptotic raes in other two cells. SeO2 could down-regulate the mean fluorescent intensity of Bcl-2 from 65.8 to 9.6 in A549, but not in GLC-82 and in PG cells, up-regulate wild type p53 level in all three cells. SeO2 decreased the ROS and Ca2+ level markedly within three tested cells.Conclusion: SeO2 showed anti-tumor effect via apoptosis pathway in three lung cancer cell lines. The decrease of ROS and Ca2+ level within cells as well as regulation of Bcl-2 and p53 expression may play important roles in above apoptotic procedure.

  10. Oral bacteria in pancreatic cancer: mutagenesis of the p53 tumour suppressor gene.

    Science.gov (United States)

    Öğrendik, Mesut

    2015-01-01

    Carcinoma of exocrine pancreas is the fourth leading cause of cancer deaths, worldwide. The prevalence of this disease is very high in patients with chronic pancreatitis. Orodigestive cancers are frequently seen in patients with periodontitis. These findings suggest that this type of cancer may have some bacterial origins. This study hypothesizes that the peptidyl arginine deaminase (PAD) enzymes found in oral bacteria may be responsible for the p53 point mutations that occur in patients with pancreatic cancer. Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola possess the PAD enzyme, and p53 arginine mutations have been detected in patients with pancreatic cancer. Moreover, the Pro allele p53Arg72-Pro is a risk factor for the development of this cancer. Anti-P. gingivalis antibody titers have been found to be higher in patients with pancreatic cancer as compared to healthy controls. The hypothesis in question can be tested if the DNA of P. gingivalis or the antibodies against P. gingivalis can be detected in patients with the p53 arginine mutation.If this hypothesis is true, it could reveal the real cause of pancreatic cancer, which is a fatal disease. Further studies are necessary in order to confirm this hypothesis.

  11. P53 alters the cytotoxicity and genotoxicity for oxidized graphene in human B-lymphoblastoid cells

    Science.gov (United States)

    Petibone, Dayton Matthew

    Widespread use of oxidized graphene nanomaterials in industry, medicine, and consumer products raises concern about potential adverse impacts on human health. The p53 tumor suppressor protein is crucial to maintaining cellular and genetic stability to prevent carcinogenesis. Here, we show that oxygen functionalized graphene (f-G) absorption and p53 functional status correlate with cytotoxicity and genotoxicity in human B-lymphoblastoid cells. Trends in f-G absorption by were dose-dependent. Cells with functional p53 exposed to f-G arrested in G0/G1 phase of the cell cycle, suppressed f-G induced reactive oxygen species (ROS), and had elevated apoptosis. While compared to p53 competent cells, the p53 deficient cells exposed to f-G accumulated in S-phase of the cell cycle, had elevated ROS levels, and evaded apoptosis. The f-G genotoxicity was evident as increased loss-of-heterozygosity mutants independent of p53 status, and structural chromosome damage in p53 deficient cells. These findings have broad implications for the safety and efficacy of oxidized graphene nanomaterials in industrial, consumer products and biomedical applications.

  12. 热休克蛋白HSP70和抑癌基因P53、PCNA在人类喉癌及癌旁组织中的表达及意义%Expression and significance of HSP70,P53 and PCNA in human,s larynx cancer

    Institute of Scientific and Technical Information of China (English)

    姚俊; 王军; 阮晓文; 罗国庆; 崔德威; 张钦明

    2003-01-01

    目的探讨热休克蛋白(heat shock Proteins,HSP)HSP70、抑癌基因突变蛋白(P53)、增殖细胞核抗原(PCNA)在人类喉癌及癌旁组织中的表达及意义.方法采用免疫组化S-P法检测HSP70蛋白、P53和PCNA在人类喉癌及癌旁组织中的表达情况,并应用统计学方法结合临床和随访资料对它们的相关性进行分析.结果HSP70、P53、PCNA的表达可能与喉癌的发生发展有关,并对喉癌的预后起指导意义.

  13. [Risk factors for cervico-uterine cancer associated to HPV: p53 codon 72 polymorphism in women attending hospital care].

    Science.gov (United States)

    Sifuentes Alvarez, A; Reyes Romero, Miguel

    2003-01-01

    In codon 72 of the p53 antioncogene there are two alleles, arginine and proline; the arg/arg genotype has recently been identified as a risk factor for developing of cervicouterine cancer (CuCa) associated to human papillomavirus (HVP) infection. The aim of this work was to determine in a sample of women the frequency of proline-arginine alleles and genotypes of p53 codon 72. The study was conducted in a sample of inpatient women at the hospital. p53 codon 72 alleles were determined in genomic ADN by amplification of specific sequences by chi 2 test. From 102 analyzed samples, p53-arginine allele corresponded to 67.64% and p53-proline allele corresponded to 32.36%; 47 women (46.10%) were arg/arg homocygotes, 11 women (10.77%) were pro/pro homocygotes, 44 women (43.13%) were arg/pro heterocigotes; the genotype distribution was within the Hardy-Weinberg equilibrium. The detection of a high percentage of arginine homocygotes suggests that this genotype, considered as a risk factor for cancer associated to oncogenic HPV, has a high prevalence in the north of Mexico. The determination of this kind of polymorphisms is important as preventive action with regard to identification of risk factors for CaCu associated to HPV infection.

  14. Optimized polymerase chain reaction-based single-strand conformation polymorphism analysis of p53 gene applied to Bulgarian patients with invasive breast cancer.

    Science.gov (United States)

    Krasteva, M E; Garanina, Z; Georgieva, E I

    2003-11-01

    During the last few decades a substantial amount of evidence has accumulated proving that the abrogation of the normal p53 pathway is a critical step in the initiation and progression of tumors. Decoding the genetic mechanisms involved in carcinogenesis requires screening for consistent genetic tumor alterations, including those concerning the p53 gene. Thus, practical, efficient, and inexpensive techniques for accurate determination of p53 mutational status are needed. Polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis is considered to be a useful tool to investigate the role of the p53 gene in the development and progression of human cancers. The sensitivity of the method can be increased considerably by varying the experimental conditions. Here we demonstrate a scheme of PCR-SSCP optimization for detection of p53 gene mutations of patients with various cancers. Optimal conditions for PCRSSCP of p53 exons 4-9 are reported. Such PCR-SSCP optimization could allow an increase in the sensitivity and reproducibility of the technique and facilitates screening of large series of patients to assess the clinical significance of p53 mutations in human cancers. Using the optimized PCR-SSCP analysis we screened Bulgarian patients with invasive breast cancer for p53 gene mutations and registered a 33.33% frequency of mutations. To date, there are no data concerning the p53 status of Bulgarian breast cancer patients. Screening for p53 gene mutations enables an accurate and routine determination of the p53 status of patients with cancer and may be applied in clinical oncology to cancer diagnosis, prediction of prognosis and response to treatment.

  15. Role of p53 and CDKN2A Inactivation in Human Squamous Cell Carcinomas

    Directory of Open Access Journals (Sweden)

    Alessia Pacifico

    2007-01-01

    Several studies have shown that human SCCs harbour unique mutations in the p53 gene as well as inactivation of the CDKN2A gene. While mutations in the p53 gene are induced by UV radiation and represent tumor initiating events, the majority of alterations detected in the CDKN2A gene do not appear to be UV-dependent. In conclusion, in addition to p53 mutations, silencing of the CDKN2A gene might play a significant role in SCC development.

  16. Altered-function p53 missense mutations identified in breast cancers can have subtle effects on transactivation

    Science.gov (United States)

    Jordan, Jennifer J.; Inga, Alberto; Conway, Kathleen; Edmiston, Sharon; Carey, Lisa A.; Wu, Lin; Resnick, Michael A.

    2010-01-01

    Mutations of the sequence-specific master regulator p53 that alter transactivation function from promoter response elements (REs) could result in changes in the strength of gene activation or spectra of genes regulated. Such mutations in this tumor suppressor might lead to dramatic phenotypic changes and diversification of cell responses to stress. We have determined “functional fingerprints” of sporadic breast cancer-related p53 mutants many of which are also associated with familial cancer proneness such as the Li-Fraumeni Syndrome and germline BRCA1/2 mutant-associated cancers. The ability of p53, wild type and mutants, to transactivate from 11 human target REs has been assessed at variable expression levels using a cellular, isogenomic yeast model system that allows for the rapid analysis of p53 function using a qualitative and a quantitative reporter. Among 50 missense mutants, 29 were classified as loss-of-function. The remaining 21 retained transactivation towards at least one RE. At high levels of galactose induced p53 expression, 12/21 mutants that retain transactivation appeared similar to WT. When the level of galactose was reduced, transactivation defects could be revealed suggesting that some breast cancer related mutants can have subtle changes in transcription. These findings have been compared with clinical data from an ongoing neoadjuvant chemotherapy treatment trial for locally advanced breast tumors. The functional and nonfunctional missense mutations may distinguish tumors in terms of demographics, appearance and relapse, implying that heterogeneity in the functionality of specific p53 mutations could impact clinical behavior and outcome. PMID:20407015

  17. FBXW7-mutated colorectal cancer cells exhibit aberrant expression of phosphorylated-p53 at Serine-15

    Science.gov (United States)

    Normatova, Makhliyo; Babaei-Jadidi, Roya; Tomlinson, Ian; Nateri, Abdolrahman S.

    2015-01-01

    FBXW7 mutations occur in a variety of human cancers including colorectal cancer (CRC). Elucidating its mechanism of action has become crucial for cancer therapy; however, it is also complicated by the fact that FBXW7 can influence many pathways due to its role as an E3-ubiquitin ligase in proteasome degradation. FBXW7 and TP53 are tumour suppressors intensively implicated in colorectal carcinogenesis. Deletion mutations in these two genes in animal models mark the progression from adenoma to carcinoma. Although still largely unknown, the last defense mechanism against CRC at the molecular level could be through a synergistic effect of the two genes. The underlying mechanism requires further investigation. In our laboratory, we have used a phospho-kinase profiler array to illustrate a potential molecular link between FBXW7 and p53 in CRC cells. In vitro and in vivo assessments demonstrated aberrant induction of phosphorylated p53 at Serine 15 [phospho-p53(Ser15)] in human FBXW7-deficient CRC cells as compared to their FBXW7-wild-type counterparts. FBXW7 loss in HCT116 cells promoted resistance to oxaliplatin. Immunoblotting data further confirmed that reduction of phospho-p53(Ser15) may contribute to the decreased efficacy of therapy in FBXW7-mutated CRC cells. The findings may suggest the applicability of phospho-p53(Ser15) as an indicative marker of FBXW7-mutations. Phospho-p53(Ser15) regulation by FBXW7 E3-ligase activity could provide important clues for understanding FBXW7 behavior in tumour progression and grounds for its clinical applicability thereafter. PMID:25860929

  18. Suberoyl bis-hydroxamic acid induces p53-dependent apoptosis of MCF-7 breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Zhi-gang ZHUANG; Fei FEI; Ying CHEN; Wei JIN

    2008-01-01

    Aim: To study the effects of suberoyl bis-hydroxamic acid (SBHA), an inhibitor of histone deacetylases, on the apoptosis of MCF-7 breast cancer cells. Meth-ods: Apoptosis in MCF-7 cells induced by SBHA was demonstrated by flow cytometric analysis, morphological observation, and DNA ladder. Mitochondrial membrane potential (△ψm) was measured using the fluorescent probe JC-1. The expressions of p53, p21, Bax, and PUMA were determined using RT-PCR or Western blotting analysis after the MCF-7 cells were treated with SBHA or p53 siRNA. Results: SBHA induced apoptosis in MCF-7 cells. The expressions of p53, p21, Bax, and PUMA were induced, and △ψm collapsed after treatment with SBHA. p53 siRNA abrogated the SBHA-induced apoptosis and the expressions of p53, p21, Bax, and PUMA. Conclusion: The activation of the p53 pathway is involved in SBHA-induced apoptosis in MCF-7 cells.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Impact of Alu repeats on the evolution of human p53 binding sites

    Directory of Open Access Journals (Sweden)

    Sirotin Michael V

    2011-01-01

    Full Text Available Abstract Background The p53 tumor suppressor protein is involved in a complicated regulatory network, mediating expression of ~1000 human genes. Recent studies have shown that many p53 in vivo binding sites (BSs reside in transposable repeats. The relationship between these BSs and functional p53 response elements (REs remains unknown, however. We sought to understand whether the p53 REs also reside in transposable elements and particularly in the most-abundant Alu repeats. Results We have analyzed ~160 functional p53 REs identified so far and found that 24 of them occur in repeats. More than half of these repeat-associated REs reside in Alu elements. In addition, using a position weight matrix approach, we found ~400,000 potential p53 BSs in Alu elements genome-wide. Importantly, these putative BSs are located in the same regions of Alu repeats as the functional p53 REs - namely, in the vicinity of Boxes A/A' and B of the internal RNA polymerase III promoter. Earlier nucleosome-mapping experiments showed that the Boxes A/A' and B have a different chromatin environment, which is critical for the binding of p53 to DNA. Here, we compare the Alu-residing p53 sites with the corresponding Alu consensus sequences and conclude that the p53 sites likely evolved through two different mechanisms - the sites overlapping with the Boxes A/A' were generated by CG → TG mutations; the other sites apparently pre-existed in the progenitors of several Alu subfamilies, such as AluJo and AluSq. The binding affinity of p53 to the Alu-residing sites generally correlates with the age of Alu subfamilies, so that the strongest sites are embedded in the 'relatively young' Alu repeats. Conclusions The primate-specific Alu repeats play an important role in shaping the p53 regulatory network in the context of chromatin. One of the selective factors responsible for the frequent occurrence of Alu repeats in introns may be related to the p53-mediated regulation of Alu

  1. Mutant p53 confers chemoresistance in non-small cell lung cancer by upregulating Nrf2.

    Science.gov (United States)

    Tung, Min-Che; Lin, Po-Lin; Wang, Yao-Chen; He, Tsung-Ying; Lee, Ming-Ching; Yeh, Sauh D; Chen, Chih-Yi; Lee, Huei

    2015-12-08

    Nrf2 is a key transcription factor for genes coding for antioxidants, detoxification enzymes, and multiple drug resistance and it also confers resistance to anticancer drugs. Here, we hypothesized that mutant p53 could upregulate Nrf2 expression at the transcriptional level, thereby conferring cisplatin resistance in non-small cell lung cancer (NSCLC). Luciferase reporter assays and real-time PCR analysis indicated that the Nrf2 promoter activity and its mRNA levels were markedly suppressed by wild-type p53, but not by mutant p53. Chromatin immunoprecipitation (ChIP) further confirmed that wild-type p53 binds at the p53 putative binding site to block Sp1 binding to the Nrf2 promoter and consequently to suppress the Nrf2 promoter activity. The MTT assay indicated that an increase in Nrf2 expression by mutant p53 is responsible for cisplatin resistance. Among the Nrf2 downstream genes, Bcl-2 and Bcl-xL contribute more strongly to Nrf2-mediated cisplatin resistance when compared with heme oxygenase 1 (HO-1). Cox regression analysis showed that patients with high-Nrf2, high-Bcl-2, high-Bcl-xL mRNA tumors were more commonly occurred unfavorable response to cisplatin-based chemotherapy than their counterparts. The prognostic significance of Nrf2 mRNA levels on OS and RFS was also observed in patients who have received cisplatin-based chemotherapy, particularly in p53-mutant patients. Collectively, mutant p53 may confer cisplatin resistance via upregulation of Nrf2 expression, and Nrf2 mRNA level may predict chemotherapeutic response and outcomes in NSCLC.

  2. Aurora-A induces cell survival and chemoresistance by activation of Akt through a p53-dependent manner in ovarian cancer cells.

    Science.gov (United States)

    Yang, Hua; He, Lili; Kruk, Patricia; Nicosia, Santo V; Cheng, Jin Q

    2006-11-15

    Aurora-A is frequently altered in epithelial malignancies. Overexpressing Aurora-A induces centrosome amplification and G2/M cell cycle progression. We have previously shown elevated level of Aurora-A in ovarian cancer and activation of telomerase by Aurora-A in human mammary and ovarian epithelia. Here we report that Aurora-A protects ovarian cancer cells from apoptosis induced by chemotherapeutic agent and activates Akt pathway in a p53-dependent manner. Ectopic expression of Aurora-A renders cells resistant to cisplatin (CDDP), etoposide and paclitaxel-induced apoptosis and stimulates Akt1 and Akt2 activity in wild-type p53 but not p53-null ovarian cancer cells. Aurora-A inhibits cytochrome C release and Bax conformational change induced by CDDP. Knockdown of Aurora-A by RNAi sensitizes cells to CDDP-induced apoptosis and decreases phospho-Akt level in wild-type p53 cells. Reintroduction of p53 decreases Akt1 and Akt2 activation and restores CDDP sensitivity in p53-null but not p53-null-Aurora-A cells. Inhibition of Akt by small molecule inhibitor, API-2, overcomes the effects of Aurora-A-on cell survival and Bax mitochondrial translocation. Taken collectively, these data indicate that Aurora-A activates Akt and induces chemoresistance in a p53-dependent manner and that inhibition of Akt may be an effective means of overcoming Aurora-A-associated chemoresistance in ovarian cancer cells expressing wild-type p53.

  3. A Novel PTEN/Mutant p53/c-Myc/Bcl-XL Axis Mediates Context-Dependent Oncogenic Effects of PTEN with Implications for Cancer Prognosis and Therapy

    Directory of Open Access Journals (Sweden)

    Xiaoping Huang

    2013-08-01

    Full Text Available Phosphatase and tensin homolog located on chromosome 10 (PTEN is one of the most frequently mutated tumor suppressors in human cancer including in glioblastoma. Here, we show that PTEN exerts unconventional oncogenic effects in glioblastoma through a novel PTEN/mutant p53/c-Myc/Bcl-XL molecular and functional axis. Using a wide array of molecular, genetic, and functional approaches, we demonstrate that PTEN enhances a transcriptional complex containing gain-of-function mutant p53, CBP, and NFY in human glioblastoma cells and tumor tissues. The mutant p53/CBP/NFY complex transcriptionally activates the oncogenes c-Myc and Bcl-XL, leading to increased cell proliferation, survival, invasion, and clonogenicity. Disruption of the mutant p53/c-Myc/Bcl-XL axis or mutant p53/CBP/NFY complex reverses the transcriptional and oncogenic effects of PTEN and unmasks its tumor-suppressive function. Consistent with these data, we find that PTEN expression is associated with worse patient survival than PTEN loss in tumors harboring mutant p53 and that a small molecule modulator of p53 exerts greater antitumor effects in PTEN-expressing cancer cells. Altogether, our study describes a new signaling pathway that mediates context-dependent oncogenic/tumor-suppressive role of PTEN. The data also indicate that the combined mutational status of PTEN and p53 influences cancer prognosis and anticancer therapies that target PTEN and p53.

  4. Preclinical evaluation of 4-methylthiobutyl isothiocyanate on liver cancer and cancer stem cells with different p53 status.

    Directory of Open Access Journals (Sweden)

    Evelyn Lamy

    Full Text Available Isothiocyanates from plants of the order Brassicales are considered promising cancer chemotherapeutic phytochemicals. However, their selective cytotoxicity on liver cancer has been barely researched. Therefore, in the present study, we systematically studied the chemotherapeutic potency of 4-methylthiobutyl isothiocyanate (MTBITC. Selective toxicity was investigated by comparing its effect on liver cancer cells and their chemoresistant subpopulations to normal primary hepatocytes and liver tissue slices. Additionally, in a first assessment, the in vivo tolerability of MTBITC was investigated in mice. Growth arrest at G2/M and apoptosis induction was evident in all in vitro cancer models treated with MTBITC, including populations with cancer initiating characteristics. This was found independent from TP53; however cell death was delayed in p53 compromised cells as compared to wt-p53 cells which was probably due to differential BH3 only gene regulation i. e. Noxa and its antagonist A1. In normal hepatocytes, no apoptosis or necrosis could be detected after repeated administration of up to 50 µM MTBITC. In mice, orally applied MTBITC was well tolerated over 18 days of treatment for up to 50 mg/kg/day, the highest dose tested. In conclusion, we could show here that the killing effect of MTBITC has a definite selectivity for cancer cells over normal liver cells and its cytotoxicity even applies for chemoresistant cancer initiating cells. Our study could serve for a better understanding of the chemotherapeutic properties of isothiocyanates on human liver-derived cancer cells.

  5. Lack of correlation between p53 codon 72 polymorphism and anal cancer risk

    Institute of Scientific and Technical Information of China (English)

    Simone S Contu; Grasiela Agnes; Andrea P Damin; Paulo C Contu; Mário A Rosito; Claudio O Alexandre; Daniel C Damin

    2009-01-01

    AIM: To investigate the potential role of p53 codon 72 polymorphism as a risk factor for development of anal cancer.METHODS: Thirty-two patients with invasive anal carcinoma and 103 healthy blood donors were included in the study. p53 codon 72 polymorphism was analyzed in blood samples through polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing.RESULTS: The relative frequency of each allele was 0.60 for Arg and 0.40 for Pro in patients with anal cancer,and 0.61 for Arg and 0.39 for Pro in normal controls.No significant differences in distribution of the codon 72 genotypes between patients and controls were found.CONCLUSION: These results do not support a role for the p53 codon 72 polymorphism in anal carcinogenesis.

  6. Fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of LncRNA MEG3.

    Science.gov (United States)

    Hu, Duanmin; Su, Cunjin; Jiang, Min; Shen, Yating; Shi, Aiming; Zhao, Fenglun; Chen, Ruidong; Shen, Zhu; Bao, Junjie; Tang, Wen

    2016-03-04

    There is still no suitable drug for pancreatic cancer treatment, which is one of the most aggressive human tumors. Maternally expressed gene 3 (MEG3), a LncRNA, has been suggested as a tumor suppressor in a range of human tumors. Studies found fenofibrate exerted anti-tumor roles in various human cancer cell lines. However, its role in pancreatic cancer remains unknown. The present study aimed to explore the impacts of fenofibrate on pancreatic cancer cell lines, and to investigate MEG3 role in its anti-tumor mechanisms. We used MTT assay to determine cells proliferation, genome-wide LncRNA microarray analysis to identify differently expressed LncRNAs, siRNA or pCDNA-MEG3 transfection to interfere or upregulate MEG3 expression, western blot to detect protein levels, real-time PCR to determine MEG3 level. Fenofibrate significantly inhibited proliferation of pancreatic cancer cells, increased MEG3 expression and p53 levels. Moreover, knockdown of MEG3 attenuated cytotoxicity induced by fenofibrate. Furthermore, overexpression of MEG3 induced cells death and increased p53 expression. Our results indicated fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of MEG3.

  7. Correlation of survivin, p53 and Ki-67 in laryngeal cancer Hep-2 cell proliferation and invasion

    Institute of Scientific and Technical Information of China (English)

    Shi-Geng Pei; Ju-Xiang Wang; Xue-Ling Wang; Qing-Jun Zhang; Hong Zhang

    2015-01-01

    Objective:To investigate the mechanism of survivin, p53 and Ki-67 on Hep-2 human laryngeal cancer endothelial cell proliferation and invasion.Methods:Laryngeal squamous cell carcinoma and paracancerous normal tissues were collected, total RNA was extracted from tissues,survivin,p53and Ki-67gene mRNA expression levels in laryngeal cancer and the adjacent tissues were detected by Real-time PCR. Human laryngeal cancer Hep-2 epithelial cells were selected,survivin gene was overexpressed, and cell proliferation was detected by MTT.p53 andKi-67gene expression changes in overexpressedsurvivin gene were detected by Western blot. Changes in Hep-2 cell invasive ability were studied whensurvivin was overexpressed as detected by Transwell invasion assay.Results: In the adjacent tissues, survivin,p53andKi-67 gene relative expression levels were 1.72 ± 0.9, 13.7 ± 5.7 and 5.7 ± 1.3, respectively; while in cancer tissues, gene relative expression levels were 53.7 ± 8.3, 66.7 ± 5.2 and 61.0 ± 3.1, respectively, which was significantly increased. As detected by MTT, relative cell survival rate within 12 h ofsurvivinoverexpression were: load control group, (88.5±1.6)%; overexpressed group, (90.3±1.9)%. Transwell invasion assay results indicated that overexpressedsurvivincould significantly increase the relative survival rate of cells. Conclusions:Expressions ofp53,Ki67 and survivin are increased in cancer; and there is a positive correlation betweensurvivin, p53andKi67 expressions in laryngeal carcinoma.

  8. p53 mutations in leukemia and myelodysplastic syndrome after ovarian cancer.

    Science.gov (United States)

    Leonard, Debra G B; Travis, Lois B; Addya, Kathakali; Dores, Graca M; Holowaty, Eric J; Bergfeldt, Kjell; Malkin, David; Kohler, Betsy A; Lynch, Charles F; Wiklund, Tom; Stovall, Marilyn; Hall, Per; Pukkala, Eero; Slater, Diana J; Felix, Carolyn A

    2002-05-01

    Although p53 mutations occur in alkylating agent-related leukemias, their frequency and spectrum in leukemias after ovarian cancer have not been addressed. The purpose of this study was to examine p53 mutations in leukemias after ovarian cancer, for which treatment with platinum analogues was widely used. Adequate leukemic or dysplastic cells were available in 17 of 82 cases of leukemia or myelodysplastic syndrome that occurred in a multicenter, population-based cohort of 23,170 women with ovarian cancer. Eleven of the 17 received platinum compounds and other alkylating agents with or without DNA topoisomerase II inhibitors and/or radiation. Six received other alkylating agents, in one case, with radiation. Genomic DNA was extracted and p53 exons 5, 6, 7, and 8 were amplified by PCR. Mutations and loss of heterozygosity were analyzed on the WAVE instrument (Transgenomic) followed by selected analysis by sequencing. Eleven p53 mutations involving all four exons studied and one polymorphism were identified. Genomic DNA analyses were consistent with loss of heterozygosity for four of the mutations. The 11 mutations occurred in 9 cases, such that 6 of 11 leukemias after platinum-based regimens (55%) and 3 of 6 leukemias after other treatments (50%) contained p53 mutations. Two leukemias that occurred after treatment with platinum analogues contained two mutations. Among eight mutations in leukemias after treatment with platinum analogues, there were four G-to-A transitions and one G-to-C transversion. p53 mutations are common in leukemia and myelodysplastic syndrome after multiagent therapy for ovarian cancer. The propensity for G-to-A transitions may reflect specific DNA damage in leukemias after treatment with platinum analogues.

  9. The Double Role of p53 in Cancer and Autoimmunity and Its Potential as Therapeutic Target.

    Science.gov (United States)

    Fierabracci, Alessandra; Pellegrino, Marsha

    2016-11-25

    p53 is a sequence-specific short-lived transcription factor expressed at low concentrations in various tissues while it is upregulated in damaged, tumoral or inflamed tissue. In normally proliferating cells, p53 protein levels and function are tightly controlled by main regulators, i.e., MDM2 (mouse double minute 2) and MDM4 proteins. p53 plays an important role due to its ability to mediate tumor suppression. In addition to its importance as a tumor suppressor, p53 coordinates diverse cellular responses to stress and damage and plays an emerging role in various physiological processes, including fertility, cell metabolism, mitochondrial respiration, autophagy, cell adhesion, stem cell maintenance and development. Interestingly, it has been recently implicated in the suppression of autoimmune and inflammatory diseases in both mice and humans. In this review based on current knowledge on the functional properties of p53 and its regulatory pathways, we discuss the potential utility of p53 reactivation from a therapeutic perspective in oncology and chronic inflammatory disorders leading to autoimmunity.

  10. Genus beta human papillomavirus E6 proteins vary in their effects on the transactivation of p53 target genes.

    Science.gov (United States)

    White, Elizabeth A; Walther, Johanna; Javanbakht, Hassan; Howley, Peter M

    2014-08-01

    The genus beta human papillomaviruses (beta HPVs) cause cutaneous lesions and are thought to be involved in the initiation of some nonmelanoma skin cancers (NMSCs), particularly in patients with the genetic disorder epidermodysplasia verruciformis (EV). We have previously reported that at least two of the genus beta HPV E6 proteins bind to and/or increase the steady-state levels of p53 in squamous epithelial cells. This is in contrast to a well-characterized ability of the E6 proteins of cancer-associated HPVs of genus alpha HPV, which inactivate p53 by targeting its ubiquitin-mediated proteolysis. In this study, we have investigated the ability of genus beta E6 proteins from eight different HPV types to block the transactivation of p53 target genes following DNA damage. We find that the E6 proteins from diverse beta HPV species and types vary in their capacity to block the induction of MDM2, p21, and proapoptotic genes after genotoxic stress. We conclude that some genus beta HPV E6 proteins inhibit at least some p53 target genes, although perhaps not by the same mechanism or to the same degree as the high-risk genus alpha HPV E6 proteins. This study addresses the ability of various human papillomavirus E6 proteins to block the activation of p53-responsive cellular genes following DNA damage in human keratinocytes, the normal host cell for HPVs. The E6 proteins encoded by the high-risk, cancer-associated HPV types of genus alpha HPV have a well-established activity to target p53 degradation and thereby inhibit the response to DNA damage. In this study, we have investigated the ability of genus beta HPV E6 proteins from eight different HPV types to block the ability of p53 to transactivate downstream genes following DNA damage. We find that some, but not all, genus beta HPV E6 proteins can block the transactivation of some p53 target genes. This differential response to DNA damage furthers the understanding of cutaneous HPV biology and may help to explain the

  11. Involvement of hGLD-2 in cytoplasmic polyadenylation of human p53 mRNA

    DEFF Research Database (Denmark)

    Glahder, Jacob-Andreas Harald; Norrild, Bodil

    2011-01-01

    Cytoplasmic polyadenylation is a post-transcriptional mechanism regulating mRNA stability and translation. The human p53 3'-untranslated region (3'-UTR) contains two regions similar to cytoplasmic polyadenylation elements (CPEs) just upstream of the poly(A) hexanucleotide. Evaluation of the p53 CPE...... cytoplasmic poly(A) polymerase] is overexpressed instead. The stability of a luciferase mRNA containing the p53 3'-UTR downstream, is decreased when hCPEB1 is overexpressed as seen by qPCR. Expression of hGLD-2 restores the mRNA stability. This is due to elongation of the poly(A) tail as seen by a PCR......-based poly(A) test and in vitro poly(A) assay. Taken together, our results suggest that hCPEB1 and hGLD-2 are antagonizing factors regulating p53 mRNA stability....

  12. Long-term clinical and immunological effects of p53-SLP (R) vaccine in patients with ovarian cancer

    NARCIS (Netherlands)

    Leffers, Ninke; Vermeij, Renee; Hoogeboom, Baukje-Nynke; Schulze, Ute R.; Wolf, Rinze; Hamming, Ineke E.; van der Zee, Ate G.; Melief, Kees J.; van der Burg, Sjoerd H.; Daemen, Toos; Nijman, Hans W.

    2012-01-01

    Vaccine-induced p53-specific immune responses were previously reported to be associated with improved response to secondary chemotherapy in patients with small cell lung cancer. We investigated long-term clinical and immunological effects of the p53-synthetic long peptide (p53-SLP (R)) vaccine in pa

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

    Institute of Scientific and Technical Information of China (English)

    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.

  14. Potential diagnostic value of serum p53 antibody for detecting esophageal cancer: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    Full Text Available BACKGROUND: Mutant p53 protein overexpression has been reported to induce serum antibodies against p53. Various studies assessing the diagnostic value of serum p53 antibody in patients with esophageal cancer remain controversial. This study aims to comprehensively and quantitatively summarize the potential diagnostic value of serum p53 antibody in esophageal cancer. METHODS: We systematically searched PubMed and Embase until 31st May 2012, without language restriction. Studies were assessed for quality using QUADAS (quality assessment of studies of diagnostic accuracy. Positive likelihood ratio (PLR and negative likelihood ratio (NLR were pooled separately and compared with overall accuracy measures diagnostic odds ratio (DOR and symmetric summary receiver operating characteristic (sROC. The PLR and NLR and their 95% confidence interval (CI were calculated using a fixed effects model according to the Mantel-Haensed method and random effects model based on the work of Der Simonian and laird, respectively. RESULTS: Fifteen studies (cases = 1079, controls = 2260 met the inclusion criteria for the meta-analysis. Approximately 53.33% (8/15 of the included studies were of high quality (QUADAS score≥8, which were retrospective case-control studies. The summary estimates for quantitative analysis of serum p53 antibody in the diagnosis of esophageal cancer were PLR 6.95 (95% CI: 4.77-9.51, NLR 0.75 (95%CI: 0.72-0.78 and DOR 9.65 (95%CI: 7.04-13.22. However, we found significant heterogeneity between NLRs. CONCLUSIONS: The current evidence suggests serum p53 antibody has a potential diagnostic value for esophageal cancer. However, its discrimination power is not perfect because of low sensitivity. IMPACT: These results suggest that s-p53-antibody may be useful for monitoring residual tumor cells and for aiding in the selection of candidates for less invasive treatment procedures because of the high specificity of s-p53-antibody. Further studies

  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

    Institute of Scientific and Technical Information of China (English)

    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. LY294002 induces p53-dependent apoptosis of SGC7901 gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Chun-gen XING; Bao-song ZHU; Hui-hui LIU; Fang LIN; Hui-hua YAO; Zhong-qin LIANG; Zheng-hong QIN

    2008-01-01

    Aim:To study the effects of LY294002, an inhibitor of class Ⅰ phosphatidylinositol 3-kinase (PI3K), on proliferation and apoptosis of SGC7901 gastric cancer cells. Methods:The MTT assay was used to determine the cytotoxic effects of LY294002. Cell cycle distribution was analyzed using flow cytometry and apoptosis was assessed using flow cytometry analysis after staining DNA with propidium iodide. Mitochondrial membrane potential was measured using the fluorescent probe JC-1. Expression of p53 and PUMA was determined using real-time RT-PCR and West-ern blotting analysis. Results:The viability of SGC7901 cells was significantly reduced by LY294002 treatment. Expression of p53 and PUMA was induced, and mitochondrial membrane potential collapsed after treatment with LY294002. LY294002 induced apoptotic cell death. Conclusion:Activation of the p53 path-way is involved in LY294002-induced SGC7901 cell death.

  17. Chk1 inhibition activates p53 through p38 MAPK in tetraploid cancer cells.

    Science.gov (United States)

    Vitale, Ilio; Senovilla, Laura; Galluzzi, Lorenzo; Criollo, Alfredo; Vivet, Sonia; Castedo, Maria; Kroemer, Guido

    2008-07-01

    We have previously shown that tetraploid cancer cells succumb through a p53-dependent apoptotic pathway when checkpoint kinase 1 (Chk1) is depleted by small interfering RNAs (siRNAs) or inhibited with 7-hydroxystaurosporine (UCN-01). Here, we demonstrate that Chk1 inhibition results in the activating phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Depletion of p38 MAPK by transfection with a siRNA targeting the alpha isoform of p38 MAPK (p38alpha MAPK) abolishes the phosphorylation of p53 on serines 15 and 46 that is induced by Chk1 knockdown. The siRNA-mediated downregulation and pharmacological inhibition of p38alpha MAPK (with SB 203580) also reduces cell death induced by Chk1 knockdown or UCN-01. These results underscore the role of p38 MAPK as a pro-apoptotic kinase in the p53-dependant pathway for the therapeutic elimination of polyploidy cells.

  18. Cytoplasmic sequestration of the tumor suppressor p53 by a heat shock protein 70 family member, mortalin, in human colorectal adenocarcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Gestl, Erin E., E-mail: egestl@wcupa.edu [Department of Biology, West Chester University, 750 S Church Street, West Chester, PA 19383 (United States); Anne Boettger, S., E-mail: aboettger@wcupa.edu [Department of Biology, West Chester University, 750 S Church Street, West Chester, PA 19383 (United States)

    2012-06-29

    gene expression levels compared to cell lines without p53 sequestration. Our data reveal the characteristic cytoplasmic sequestration of p53 by the heat shock protein mortalin in human colorectal adenocarcinoma cell lines, as is the case for other cancers, such as glioblastomas and hepatocellular carcinomas.

  19. p53 represses human papillomavirus type 16 DNA replication via the viral E2 protein

    Directory of Open Access Journals (Sweden)

    Morgan Iain M

    2008-01-01

    Full Text Available Abstract Background Human papillomavirus (HPV DNA replication can be inhibited by the cellular tumour suppressor protein p53. However, the mechanism through which p53 inhibits viral replication and the role that this might play in the HPV life cycle are not known. The papillomavirus E2 protein is required for efficient HPV DNA replication and also regulates viral gene expression. E2 represses transcription of the HPV E6 and E7 oncogenes and can thereby modulate indirectly host cell proliferation and survival. In addition, the E2 protein from HPV 16 has been shown to bind p53 and to be capable of inducing apoptosis independently of E6 and E7. Results Here we use a panel of E2 mutants to confirm that mutations which block the induction of apoptosis via this E6/E7-independent pathway, have little or no effect on the induction of apoptosis by the E6/E7-dependent pathway. Although these mutations in E2 do not affect the ability of the protein to mediate HPV DNA replication, they do abrogate the repressive effects of p53 on the transcriptional activity of E2 and prevent the inhibition of E2-dependent HPV DNA replication by p53. Conclusion These data suggest that p53 down-regulates HPV 16 DNA replication via the E2 protein.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Natural Products Induce a G Protein-Mediated Calcium Pathway Activating p53 in Cancer Cells

    Science.gov (United States)

    van Ginkel, Paul R.; Yan, Michael B.; Bhattacharya, Saswati; Polans, Arthur S.; Kenealey, Jason D.

    2015-01-01

    Paclitaxel, etoposide, vincristine and doxorubicin are examples of natural products being used as chemotherapeutics but with adverse side effects that limit their therapeutic window. Natural products derived from plants and having low toxicity, such as quercetin, resveratrol, epigallocatechin gallate and piceatannol, have been shown to inhibit tumor cell growth both in vitro and in pre-clinical models of cancer, but their mechanisms of action have not been fully elucidated, thus restricting their use as prototypes for developing synthetic analogs with improved anti-cancer properties. We and others have demonstrated that one of the earliest and consistent events upon exposure of tumor cells to these less toxic natural products is a rise in cytoplasmic calcium, activating several pro-apoptotic pathways. We describe here a G protein/inositol 1,4,5-trisphosphate pathway (InsP3) in MDA-MB-231 human breast cancer cells that mediates between these less toxic natural products and the release of calcium from the endoplasmic reticulum. Further, we demonstrate that this elevation of intracellular calcium modulates p53 activity and the subsequent transcription of several pro-apoptotic genes encoding PIG8, CD95, PIDD, TP53INP, RRM2B, Noxa, p21 and PUMA. We conclude from our findings that less toxic natural products likely bind to a G protein coupled receptor that activates a G protein-mediated and calcium-dependent pathway resulting selectively in tumor cell death. PMID:26341291

  2. Natural products induce a G protein-mediated calcium pathway activating p53 in cancer cells.

    Science.gov (United States)

    van Ginkel, Paul R; Yan, Michael B; Bhattacharya, Saswati; Polans, Arthur S; Kenealey, Jason D

    2015-11-01

    Paclitaxel, etoposide, vincristine and doxorubicin are examples of natural products being used as chemotherapeutics but with adverse side effects that limit their therapeutic window. Natural products derived from plants and having low toxicity, such as quercetin, resveratrol, epigallocatechin gallate and piceatannol, have been shown to inhibit tumor cell growth both in vitro and in pre-clinical models of cancer, but their mechanisms of action have not been fully elucidated, thus restricting their use as prototypes for developing synthetic analogs with improved anti-cancer properties. We and others have demonstrated that one of the earliest and consistent events upon exposure of tumor cells to these less toxic natural products is a rise in cytoplasmic calcium, activating several pro-apoptotic pathways. We describe here a G protein/inositol 1,4,5-trisphosphate pathway (InsP3) in MDA-MB-231 human breast cancer cells that mediates between these less toxic natural products and the release of calcium from the endoplasmic reticulum. Further, we demonstrate that this elevation of intracellular calcium modulates p53 activity and the subsequent transcription of several pro-apoptotic genes encoding PIG8, CD95, PIDD, TP53INP, RRM2B, Noxa, p21 and PUMA. We conclude from our findings that less toxic natural products likely bind to a G protein coupled receptor that activates a G protein-mediated and calcium-dependent pathway resulting selectively in tumor cell death.

  3. Status quo of p53 in the treatment of tumors.

    Science.gov (United States)

    Guan, Yong-Song; He, Qing; Zou, Qing

    2016-10-01

    The p53 gene is pivotal for oncogenesis in a combination of mutations in oncogenes and antioncogenes. The ubiquitous loss of the p53 pathway in human cancers has generated considerable interest in developing p53-targeted cancer therapies, but current ideas and approaches targeting p53 are conflicting. Current researches focus on cancer-selective drugs with therapeutic strategies that both activate and inhibit p53. As p53 is ubiquitously lost in human cancers, the strategy of exogenous p53 addition is reasonable. However, p53 acts not equally in all cell types; thus, individualized p53 therapy is the direction of future research. To clarify the controversies on p53 for improvement of future antitumor studies, the review focuses on the available technological protocols, including their advantages and limitations in terms of future therapeutic use of p53 in the management of tumors.

  4. M-ds-P21 induces cell apoptosis in bladder cancer T24 cells through P53 independent pathway.

    Science.gov (United States)

    Wang, Haifeng; Liu, Wujiang; Jin, Jie; Zhou, Liqun; Liang, Lili; Guo, Yinglu

    2013-01-01

    To investigate the effect of M-ds-P21 on the apoptosis of bladder cancer T24 cells and its potential mechanism. Effect of M-ds-P21 on T24 cells were assessed by cell morphology and Western blot. Apoptosis was quantified by Annexin-V flow-cytometry analysis. To uncover the role of P53 in M-ds-P21-mediated apoptosis of T24 cells, we knocked down P53 before treating cells with M-ds-P21, and then assayed P21 and apoptosis-related protein by Western blot. To uncover the mechanism by which M-ds-P21 played stronger effect than ds-P21, we performed confocal microscope analyses. Both M-ds-P21 and ds-P21 treatment changed the cell morphology, leading to cell apoptosis after 3 days. Apoptosis induced by M-ds-P21 and ds-P21 treatment is not P53-dependent but caspase-dependent. Compared with ds-P21, M-ds-P21 significantly increased the bioavailability of ds-RNA in T24 cells. M-ds-P21 treatment induces more apoptotic population than ds-P21 does. The mechanism for stronger effect of M-ds-P21 is partly due to the enhanced bioavailability of ds-RNA in human bladder cancer T24 cells, and not P53-dependent but caspase-dependent.

  5. Secondary breast cancer in patients presenting with osteosarcoma: possible involvement of germline p53 mutations.

    Science.gov (United States)

    Russo, C L; McIntyre, J; Goorin, A M; Link, M P; Gebhardt, M C; Friend, S H

    1994-01-01

    Second malignancies following treatment for osteosarcoma are unusual. Breast cancer occurring in patients with osteosarcoma has been reported following therapeutic chest irradiation. We now report three cases of breast cancer occurring in young women who were successfully treated for osteosarcoma. These women had not received therapeutic chest irradiation and in two of the three women there was no family history of breast cancer. Peripheral blood was available for study from one case. Of import, this case demonstrated a germline mutation in exon 7 of the tumor suppressor gene, p53. The mutation was detected by constant denaturing gradient gel electrophoresis and confirmed by DNA sequencing. In this particular patient, inactivation of the p53 gene may be involved in the development of both the first and second malignancy.

  6. An Efficient Light-Inducible P53 Expression System for Inhibiting Proliferation of Bladder Cancer Cell

    Science.gov (United States)

    Lin, Fan; Dong, Liang; Wang, Weiming; Liu, Yuchen; Huang, Weiren; Cai, Zhiming

    2016-01-01

    Optogenetic gene expression systems enable spatial-temporal modulation of gene transcription and cell behavior. Although applications in biomedicine are emerging, the utility of optogenetic gene switches remains elusive in cancer research due to the relative low gene activation efficiency. Here, we present an optimized CRISPR-Cas9-based light-inducible gene expression device that controls gene transcription in a dose-dependent manner. To prove the potential utility of this device, P53 was tested as a functional target in the bladder cancer cell models. It was illustrated that the light-induced P53 inhibited proliferation of 5637 and UMUC-3 cell effectively. The “light-on” gene expression system may demonstrate a novel therapeutic strategy for bladder cancer intervention. PMID:27766041

  7. Quiescence does not affect p53 and stress response by irradiation in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Jiawen [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Itahana, Koji, E-mail: koji.itahana@duke-nus.edu.sg [Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School (Singapore); Baskar, Rajamanickam, E-mail: r.baskar@nccs.com.sg [Molecular Radiobiology Laboratory, Division of Cellular and Molecular Research (Singapore); Department of Radiation Oncology, National Cancer Centre (Singapore)

    2015-02-27

    Cells in many organs exist in both proliferating and quiescent states. Proliferating cells are more radio-sensitive, DNA damage pathways including p53 pathway are activated to undergo either G{sub 1}/S or G{sub 2}/M arrest to avoid entering S and M phase with DNA damage. On the other hand, quiescent cells are already arrested in G{sub 0}, therefore there may be fundamental difference of irradiation response between proliferating and quiescent cells, and this difference may affect their radiosensitivity. To understand these differences, proliferating and quiescent human normal lung fibroblasts were exposed to 0.10–1 Gy of γ-radiation. The response of key proteins involved in the cell cycle, cell death, and metabolism as well as histone H2AX phosphorylation were examined. Interestingly, p53 and p53 phosphorylation (Ser-15), as well as the cyclin-dependent kinase inhibitors p21 and p27, were induced similarly in both proliferating and quiescent cells after irradiation. Furthermore, the p53 protein half-life, and expression of cyclin A, cyclin E, proliferating cell nuclear antigen (PCNA), Bax, or cytochrome c expression as well as histone H2AX phosphorylation were comparable after irradiation in both phases of cells. The effect of radioprotection by a glycogen synthase kinase 3β inhibitor on p53 pathway was also similar between proliferating and quiescent cells. Our results showed that quiescence does not affect irradiation response of key proteins involved in stress and DNA damage at least in normal fibroblasts, providing a better understanding of the radiation response in quiescent cells, which is crucial for tissue repair and regeneration. - Highlights: • p53 response by irradiation was similar between proliferating and quiescent cells. • Quiescent cells showed similar profiles of cell cycle proteins after irradiation. • Radioprotection of GSK-3β inhibitor caused similar effects between these cells. • Quiescence did not affect p53 response despite its

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

    Energy Technology Data Exchange (ETDEWEB)

    Kruschewski, Martin, E-mail: martin.kruschewski@charite.de; Mueller, Kathrin; Lipka, Sybille [Department of Surgery, Campus Benjamin Franklin, Charité-University Medicine Berlin, Hindenburgdamm 30, 12200 Berlin (Germany); Budczies, Jan; Noske, Aurelia [Institute of Pathology, Campus Mitte, Charité-University Medicine Berlin, Charitéplatz 1, 10117 Berlin (Germany); Buhr, Heinz Johannes [Department of Surgery, Campus Benjamin Franklin, Charité-University Medicine Berlin, Hindenburgdamm 30, 12200 Berlin (Germany); Elezkurtaj, Sefer [Institute of Pathology, Campus Mitte, Charité-University Medicine Berlin, Charitéplatz 1, 10117 Berlin (Germany)

    2011-03-11

    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.

  9. p53 codon 72 polymorphism and liver cancer susceptibility: A meta-analysis of epidemiologic studies

    Institute of Scientific and Technical Information of China (English)

    Xi Chen; Fei Liu; Bo Li; Yong-Gang Wei; Lv-Nan Yan; Tian-Fu Wen

    2011-01-01

    AIM: To evaluate the association between p53 codon 72 polymorphism and liver cancer risk by means of meta-analysis.METHODS: Two investigators independently searched the Medline, Embase and Chinese Biomedicine databas-es. Summary odds ratios and 95% CI for p53 codon 72 polymorphism and liver cancer were calculated in .xed-effects model (Mantel-Haenszel method) and random-effects model (DerSimonian and Laird method) when appropriate.RESULTS: This meta-analysis included 1115 liver can-cer cases and 1778 controls. The combined results based on all studies showed that there was a statisti-cally signi.cant link between Pro/Pro genotype and liver cancer, but not between Arg/Arg or Pro/Arg genotype and liver cancer. When stratifying for race, similar re-sults were obtained, i.e. patients with liver cancer had a signi.cantly higher frequency of Pro/Pro genotype than non-cancer patients among Asians. After stratifying the various studies by control source, gender, family history of liver cancer and chronic hepatitis virus infection, we found that (1) patients among hospital-based studies had a significantly higher frequency of Pro/Pro and a signi.cantly lower frequency of Arg/Arg genotype than individuals without cancer; (2) female patients with liver cancer had a significantly lower frequency of Arg/Arg and a higher frequency of Pro/Arg+Pro/Pro genotypes than female individuals without cancer; (3) subgroup analyses for family history of liver cancer did not re-veal any signi.cant association between p53 codon 72 polymorphism and liver cancer development; and (4) patients with negative hepatitis virus infection had a sig-ni.cantly higher frequency of Pro/Pro and a signi.cantly lower frequency of Arg/Arg genotype than individuals without cancer.CONCLUSION: This meta-analysis suggests that the p53 codon 72 polymorphism may be associated with liver cancer among Asians.

  10. MicroRNA Control of p53.

    Science.gov (United States)

    Liu, Juan; Zhang, Cen; Zhao, Yuhan; Feng, Zhaohui

    2017-01-01

    Tumor suppressor p53 plays a central role in tumor suppression. As a transcription factor, p53 mainly exerts its tumor suppressive function through transcriptional regulation of many target genes. To maintain the proper function of p53, p53 protein level and activity are exquisitely controlled by a group of positive and negative regulators in cells. Thus, p53, its regulators, and regulated genes form a complicated p53 signaling network. microRNAs (miRNAs) are a group of endogenous small non-coding RNA molecules. miRNAs play an important role in regulation of gene expression by blocking translational protein synthesis and/or degrading target mRNAs. Recent studies have demonstrated that p53 and its network are regulated by miRNAs at multiple levels. Some miRNAs regulate the level and function of p53 through directly targeting p53, whereas some other miRNAs target regulators of p53, such as MDM2 and MDM4, to indirectly regulate the activity and function of p53. On the other hand, p53 also regulates the transcriptional expression and the biogenesis of a group of miRNAs, which contributes to the tumor suppressive function of p53. p53 is the most frequently mutated gene in human cancer. Many tumor-associated mutant p53, which have "gain-of-function" activities in tumorigenesis independently of wild type p53, can regulate the expression of different miRNAs and modulate the biogenesis of specific miRNAs to promote tumorigenesis. These findings have demonstrated that miRNAs are important regulators and mediators of p53 and its signaling pathway, which highlights a pivotal role of miRNAs in the p53 network and cancer. J. Cell. Biochem. 118: 7-14, 2017. © 2016 Wiley Periodicals, Inc.

  11. Stathmin/oncoprotein 18, a microtubule regulatory protein, is required for survival of both normal and cancer cell lines lacking the tumor suppressor, p53.

    Science.gov (United States)

    Carney, Bruce K; Cassimeris, Lynne

    2010-05-01

    Stathmin, a microtubule regulatory protein, is overexpressed in many cancers and required for survival of several cancer lines. In a study of breast cancer cell lines(1) proposed that stathmin is required for survival of cells lacking p53, but this hypothesis was not tested directly. Here we tested their hypothesis by examining cell survival in cells depleted of stathmin, p53 or both proteins. Comparing HCT116 colon cancer cell lines differing in TP53 genotype, stathmin depletion resulted in significant death only in cells lacking p53. As a second experimental system, we compared the effects of stathmin depletion from HeLa cells, which normally lack detectable levels of p53 due to expression of the HPV E6 protein. Stathmin depletion caused a large percentage of HeLa cells to die. Restoring p53, by depletion of HPV E6, rescued HeLa cells from stathmin-depletion induced death. Cleaved PARP was detected in HCT116(p53-/-) cells depleted of stathmin and cell death in stathmin-depleted HeLa cells was blocked by the caspase inhibitor Z-VAD-FMK, consistent with apoptotic death. The stathmin-dependent survival of cells lacking p53 was not confined to cancerous cells because both proteins were required for survival of normal human fibroblasts. In HCT116 and HeLa cells, depletion of both stathmin and p53 leads to a cell cycle delay through G(2). Our results demonstrate that stathmin is required for cell survival in cells lacking p53, suggesting that stathmin depletion could be used therapeutically to induce apoptosis in tumors without functional p53.

  12. P53 in human melanoma fails to regulate target genes associated with apoptosis and the cell cycle and may contribute to proliferation

    Directory of Open Access Journals (Sweden)

    Rizos Helen

    2011-05-01

    Full Text Available Abstract Background Metastatic melanoma represents a major clinical problem. Its incidence continues to rise in western countries and there are currently no curative treatments. While mutation of the P53 tumour suppressor gene is a common feature of many types of cancer, mutational inactivation of P53 in melanoma is uncommon; however, its function often appears abnormal. Methods In this study whole genome bead arrays were used to examine the transcript expression of P53 target genes in extracts from 82 melanoma metastases and 6 melanoma cell lines, to provide a global assessment of aberrant P53 function. The expression of these genes was also examined in extracts derived from diploid human melanocytes and fibroblasts. Results The results indicated that P53 target transcripts involved in apoptosis were under-expressed in melanoma metastases and melanoma cell lines, while those involved in the cell cycle were over-expressed in melanoma cell lines. There was little difference in the transcript expression of P53 target genes between cell lines with null/mutant P53 compared to those with wild-type P53, suggesting that altered expression in melanoma was not related to P53 status. Similarly, down-regulation of P53 by short-hairpin RNA (shRNA had limited effect on P53 target gene expression in melanoma cells, whereas there were a large number of P53 target genes whose mRNA expression was significantly altered by P53 inhibition in melanocytes. Analysis of whole genome gene expression profiles indicated that the ability of P53 to regulate genes involved in the cell cycle was significantly reduced in melanoma cells. Moreover, inhibition of P53 in melanocytes induced changes in gene expression profiles that were characteristic of melanoma cells and resulted in increased proliferation. Conversely, knockdown of P53 in melanoma cells resulted in decreased proliferation. Conclusions These results indicate that P53 target genes involved in apoptosis and cell

  13. Abnormal mitosis triggers p53-dependent cell cycle arrest in human tetraploid cells.

    Science.gov (United States)

    Kuffer, Christian; Kuznetsova, Anastasia Yurievna; Storchová, Zuzana

    2013-08-01

    Erroneously arising tetraploid mammalian cells are chromosomally instable and may facilitate cell transformation. An increasing body of evidence shows that the propagation of mammalian tetraploid cells is limited by a p53-dependent arrest. The trigger of this arrest has not been identified so far. Here we show by live cell imaging of tetraploid cells generated by an induced cytokinesis failure that most tetraploids arrest and die in a p53-dependent manner after the first tetraploid mitosis. Furthermore, we found that the main trigger is a mitotic defect, in particular, chromosome missegregation during bipolar mitosis or spindle multipolarity. Both a transient multipolar spindle followed by efficient clustering in anaphase as well as a multipolar spindle followed by multipolar mitosis inhibited subsequent proliferation to a similar degree. We found that the tetraploid cells did not accumulate double-strand breaks that could cause the cell cycle arrest after tetraploid mitosis. In contrast, tetraploid cells showed increased levels of oxidative DNA damage coinciding with the p53 activation. To further elucidate the pathways involved in the proliferation control of tetraploid cells, we knocked down specific kinases that had been previously linked to the cell cycle arrest and p53 phosphorylation. Our results suggest that the checkpoint kinase ATM phosphorylates p53 in tetraploid cells after abnormal mitosis and thus contributes to proliferation control of human aberrantly arising tetraploids.

  14. P53 codon 72 polymorphism and ovarian cancer risk: a meta-analysis

    Institute of Scientific and Technical Information of China (English)

    Zhizhong Zhang; Cuangbo Fu; Meilin Wang; Na Tong; Shizhi Wang; Zhengdong Zhang

    2008-01-01

    Objective: p53 is a tumor suppressor gene and is involved in the etiology of ovarian cancer. Studies investigating the associations between the p53 codon 72 polymorphism and ovarian cancer risk showed conflicting results. We performed this meta-analysis from eligible studies to evaluate this purported relationship. Methods: This meta-analysis was performed from 9 case-control studies, including 825 ovarian cases and 1073 controls. The fixed and random effect models were used to estimate the odds ratios(ORs) for various contrasts of this polymorphism. Results: The combined results based on all studies showed that a significantly decreased risk was associated with the variant Pro/Pro genotype, compared with Arg/Pro+Arg/Arg genotypes(OR, 0.70; 95%CI, 0.51-0.95). When stratifying the studies by ethnicity, we found that individuals with the variant genotype Pro/Pro had a significantly decreased risk of ovarian cancer compared with Arg/Arg genotype(OR, 0.43; 95%CI, 0.20-0.89) and Arg/Pro+Arg/Arg genotypes(OR, 0.61; 95%CI, 0.37-0.99) among Africans. Conclusion: This meta-analysis suggests that the p53 codon 72 polymorphism may contribute to genetic susceptibility to ovarian cancer. More studies based on larger sample size should be performed to confirm the findings.

  15. Overexpressed ubiquitin ligase Cullin7 in breast cancer promotes cell proliferation and invasion via down-regulating p53

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Hongsheng [Department of Histology and Embryology, Guangdong Medical College, Dongguan 523808, Guangdong (China); Wu, Fenping [The 7th People’s Hospital of Chengdu, Chengdu 610041, Sichuan (China); Wang, Yan [The Second School of Clinical Medicine, Guangdong Medical College, Dongguan 523808, Guangdong (China); Yan, Chong [School of Pharmacy, Guangdong Medical College, Dongguan 523808, Guangdong (China); Su, Wenmei, E-mail: wenmeisutg@126.com [Oncology of Affiliated Hospital Guangdong Medical College, Zhanjiang 524000, Guangdong (China)

    2014-08-08

    Highlights: • Cullin7 is overexpressed in human breast cancer samples. • Cullin7 stimulated proliferation and invasion of breast cancer cells. • Inhibition of p53 contributes to Cullin7-induced proliferation and invasion. - Abstract: Ubiquitin ligase Cullin7 has been identified as an oncogene in some malignant diseases such as choriocarcinoma and neuroblastoma. However, the role of Cullin7 in breast cancer carcinogenesis remains unclear. In this study, we compared Cullin7 protein levels in breast cancer tissues with normal breast tissues and identified significantly higher expression of Cullin7 protein in breast cancer specimens. By overexpressing Cullin7 in breast cancer cells HCC1937, we found that Cullin7 could promote cell growth and invasion in vitro. In contrast, the cell growth and invasion was inhibited by silencing Cullin7 in breast cancer cell BT474. Moreover, we demonstrated that Cullin7 promoted breast cancer cell proliferation and invasion via down-regulating p53 expression. Thus, our study provided evidence that Cullin7 functions as a novel oncogene in breast cancer and may be a potential therapeutic target for breast cancer management.

  16. Transient p53 suppression increases reprogramming of human fibroblasts without affecting apoptosis and DNA damage

    DEFF Research Database (Denmark)

    Rasmussen, Mikkel Aabech; Holst, Bjørn; Tümer, Zeynep;

    2014-01-01

    The discovery of human-induced pluripotent stem cells (iPSCs) has sparked great interest in the potential treatment of patients with their own in vitro differentiated cells. Recently, knockout of the Tumor Protein 53 (p53) gene was reported to facilitate reprogramming but unfortunately also led...... and DNA damage. Stable iPSC lines generated with or without p53 suppression showed comparable expression of pluripotency markers and methylation patterns, displayed normal karyotypes, contained between 0 and 5 genomic copy number variations and produced functional neurons in vitro. In conclusion...

  17. Clinical utility of recombinant adenoviral human p53 gene therapy: current perspectives

    Directory of Open Access Journals (Sweden)

    Chen GX

    2014-10-01

    Full Text Available Guang-xia Chen,1,* Shu Zhang,2–4,* Xiao-hua He,1 Shi-yu Liu,1 Chao Ma,2–4 Xiao-Ping Zou2–4 1Department of Gastroenterology, First People’s Hospital of Xuzhou, Xuzhou, Jiangsu Province, People’s Republic of China; 2Department of Gastroenterology, Drum Tower Hospital, 3Medical School of Nanjing University, 4Jiangsu Clinical Medical Center of Digestive Disease, Nanjing, People’s Republic of China *These authors have contributed equally to the paperAbstract: Gene therapy has promised to be a highly effective antitumor treatment by introducing a tumor suppressor gene or the abrogation of an oncogene. Among the potential therapeutic transgenes, the tumor suppressor gene p53 serves as an attractive target. Restoration of wild-type p53 function in tumors can be achieved by introduction of an intact complementary deoxyribonucleic acid copy of the p53 gene using a suitable viral vector, in most cases an adenoviral vector (Adp53. Preclinical in vitro and in vivo studies have shown that Adp53 triggers a dramatic tumor regression response in various cancers. These viruses are engineered to lack certain early proteins and are thus replication defective, including Gendicine, SCH-58500, and Advexin. Several types of tumor-specific p53-expressing conditionally replicating adenovirus vectors (known as replication-competent CRAdp53 vectors have been developed, such as ONYX 015, AdDelta24-p53, SG600-p53, OBP-702, and H101. Various clinical trials have been conducted to investigate the safety and efficiency of these adenoviral vectors. In this review we will talk about the biological mechanisms, clinical utility, and therapeutic potentials of the replication-deficient Adp53-based and replication-competent CRAdp53-based gene therapy.Keywords: adenovirus, Adp53, CRAdp53

  18. Zinc Deficiency Induces Apoptosis via Mitochondrial p53- and Caspase-Dependent Pathways in Human Neuronal Precursor Cells

    Science.gov (United States)

    Seth, Rohit; Corniola, Rikki S.; Gower-Winter, Shannon D.; Morgan, Thomas J., Jr.; Bishop, Brian; Levenson, Cathy W.

    2015-01-01

    Previous studies have shown that zinc deficiency leads to apoptosis of neuronal precursor cells in vivo and in vitro. In addition to the role of p53 as a nuclear transcription factor in zinc deficient cultured human neuronal precursors (NT-2), we have now identified the translocation of phosphorylated p53 to the mitochondria and p53-dependent…

  19. Three-year monitoring of serum p53 antibody during chemotherapy and surgery for stage IV rectal cancer.

    Science.gov (United States)

    Suzuki, Takayuki; Shimada, Hideaki; Ushigome, Mitsunori; Koike, Junichi; Funahashi, Kimihiko; Nemoto, Tetsuo; Kaneko, Hironori

    2016-04-01

    The overexpression of mutant p53 stimulates serum p53 antibody production in patients with colorectal carcinoma even in superficial tumors. Although the short-term perioperative monitoring of serum p53 antibody titers is reported to be useful in predicting tumor recurrence and patient survival in colorectal carcinoma, the clinical utility of the long-term monitoring of serum p53 antibody titers in patients with colorectal cancer remains unknown. Here, we report the 3-year monitoring of serum p53 antibody titers in a 60-year-old man with rectal cancer, clinical stage IV (T2N2M1b, lung and liver metastases), who was treated with chemotherapy and surgery. Screening tests for CEA (29.4 ng/ml), CA19-9 (41.1 U/ml), and serum p53 antibody (2170 U/ml) were positive before treatment. After chemotherapy with mFOLFOX6 + bevacizumab (B-mab), CEA and CA19-9 decreased to the normal range. However, serum p53 antibody titer remained positive (283 U/ml). After low anterior resection, the serum p53 antibody titer still remained positive (63.4 U/ml). Serum p53 antibody titer significantly changed and was associated with treatment response and tumor recurrence. In the last 6 months of the patient's life, serum p53 antibody titer gradually decreased, which possibly reflects the modification of the patient's immune response to p53 antigens.

  20. Regulation of p53 expression and apoptosis by vault RNA2-1-5p in cervical cancer cells.

    Science.gov (United States)

    Kong, Lu; Hao, Qi; Wang, Ying; Zhou, Ping; Zou, Binbin; Zhang, Yu-xiang

    2015-09-29

    nc886 or VRNA2-1 has recently been identified as a noncoding RNA instead of a vault RNA or a pre-microRNA. Several studies have reported that pre-miR-886 plays a tumor-suppressive role in a wide range of cancer cells through its activity as a cellular protein kinase RNA-activated (PKR) ligand and repressor. However, by sequencing stem-PCR products, we found that a microRNA originating from this precursor, vault RNA2-1-5p (VTRNA2-1-5p), occurs in cervical cancer cells. The expression levels of the predicted targets of VTRNA2-1-5p are negatively correlated with VTRNA2-1-5p levels by quantitative reversion transcription PCR (qRT-PCR). Previous results have shown that VTRNA2-1-5p is overexpressed in human cervical squamous cell carcinomas (CSCCs) compared with adjacent healthy tissues. Inhibition of VTRNA2-1-5p increases Bax protein expression and apoptotic cell death in cervical cancer cells. Our findings suggest that VTRNA2-1-5p has oncogenic activity related to the progression of cervical cancer. Here, we report that VTRNA2-1-5p directly targeted p53 expression and functioned as an oncomir in cervical cancer. VTRNA2-1-5p inhibition decreased cervical cancer cell invasion, proliferation, and tumorigenicity while increasing apoptosis and p53 expression. Interestingly, VTRNA2-1-5p inhibition also increased cisplatin-induced apoptosis of HeLa and SiHa cells. In human clinical cervical cancer specimens, low p53 expression and high VTRNA2-1-5p expression were positively associated.In addition, VTRNA2-1-5p was found to directly target the 5' and 3' untranslated regions (UTRs) of p53. We propose that VTRNA2-1-5p is a direct regulator of p53 and suggest that it plays an essential role in the apoptosis and proliferation of cervical cancer cells.

  1. The common germline Arg72Pro polymorphism of p53 and increased longevity in humans

    DEFF Research Database (Denmark)

    Bojesen, S.E.; Nordestgaard, Børge

    2008-01-01

    substitution in the p53 protein has important influence on cell death via increased apoptosis. Thus, the increased longevity may be due to a generally increased robustness after a diagnosis of any life-threatening disease. In contrast to widespread skepticism on the importance of SNPs in humans, this gain...

  2. HER-2,P53 and Hormonal Receptors Protein Expression as Predictive Factors in Breast Cancer Prognosis

    Institute of Scientific and Technical Information of China (English)

    seyed Mohanmmad Rabiee Hashemi; Somayeh Rabiee Hashemi

    2008-01-01

    Breast cancer is a heterogeneous disease with vari-able biological and clinical characteristics. We conducted a study to evaluate P53,HER-2/neu and hormonal receptor expression as predictors of prognosis in breast cancer. METHODS In a prospective study, we recruited 81 consecutive patients with primary operable breast cancer who were treated with mastectomy followed by locoregional radiotherapy or che-motherapy and studied the presence of P53,HER-2/neu and hormonal receptors(ER/PR) expression in tumor tissues by im-munohistochemical staining. Associations between these markers expression and clinical outcomes, including local and regional recurrence and metastasis were evaluated. Statistical analysis was performed with the SPSS software. RESUITS The mean time of follow-up was (47.3±4.6)months. Expression of P53, HER-2/neu, Estrogen receptors and progester-one receptors were observed in 31.1%, 38.5%, 31.8%and 51.7%ofthe patients, respectively. P53,HER-2/neu and Negative ER status were potent predictors of local-regional recurrence(P=0.034,0.038,0.044,respectively).Also HER-2/neu,Negative ER and Negative PR status were strong predictors of metastasis(P=0.001,0.042,0.054,respectively).CONCLUSION OP53 and HER-2/neu expression and also steroid receptors status(ER/PR status)have an important role in predict-ing the outcome of breast cancer and thus may be of value in se-lecting suitable therapeutic strategy and determining prognosis in these patients.

  3. The epidemiology of Her-2/ neu and P53 in breast cancer

    Directory of Open Access Journals (Sweden)

    Bernstein Jonine L.

    1999-01-01

    Full Text Available Breast cancer is an etiologically heterogeneous disease with marked geographical variations. Joint consideration of the relationship between specific molecular alterations and known or suspected epidemiologic risk factors for this disease should help distinguish subgroups of women that are at elevated risk of developing breast cancer. In this article, we present a comprehensive literature review of the etiologic and prognostic roles of Her-2/neu and P53 among women. In addition, we discuss the advantages and limitations of using biomarkers in epidemiological studies. We conclude that more research is needed to understand the complex relationships between genetic alterations and etiologic risk factors for breast cancer.

  4. p14ARF upregulation of p53 and enhanced effects of 5-fluorouracil in pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    张群华; 倪泉兴; 甘军; 沈兆忠; 罗建民; 金忱; 张妞; 张延龄

    2003-01-01

    Objective To investigate the synergistic antitumor effects of combined use of p14ARF gene and 5-fluorouracil (5-Fu) in pancreatic cancer.Methods A human pancreatic cancer cell line PC-3 was transfected with lipofectin-mediated recombinant p14ARF gene, and was then administered with 5-Fu. Cell growth, morphological changes, cell cycle, apoptosis, and molecular changes were measured using the MTT assay, flow cytometry, RT-PCR, Western blotting, and immunocytochemical assays.Results After transfection of p14ARF, cell growth was obviously inhibited, resulting in an accumulation of cells in the G1 phase. The proportion of cells in the G1 phase was significantly increased from 58.51% to 75.92 %, and in the S and G2/M phases decreased significantly from 20.05% to 12.60%, and from 21.44% to 11.48 %, respectively, as compared with those of the control groups. PC-3/p14ARF cells that underwent 5-Fu treatment had significantly greater G2/M phase accumulation, from 11.48% to 53.47 %. The apoptopic index was increased in PC-3/p14ARF cells from 3.64% to 19.62%. The MTT assay showed p14ARF-expressing cells were significantly more sensitive to 5-Fu (0.01-10 mg/L) than those devoid of p14ARF expression (P<0.01). Western blotting showed p14ARF upregulates p53 expression. Conclusion Combined use of p14ARF gene and 5-Fu acts synergistically to inhibit pancreatic cancer cell proliferation, suggesting a new anticancer strategy.

  5. p53 controls colorectal cancer cell invasion by inhibiting the NF-κB-mediated activation of Fascin.

    Science.gov (United States)

    Sui, Xinbing; Zhu, Jing; Tang, Haimei; Wang, Chan; Zhou, Jichun; Han, Weidong; Wang, Xian; Fang, Yong; Xu, Yinghua; Li, Da; Chen, Rui; Ma, Junhong; Jing, Zhao; Gu, Xidong; Pan, Hongming; He, Chao

    2015-09-08

    p53 mutation is known to contribute to cancer progression. Fascin is an actin-bundling protein and has been recently identified to promote cancer cell migration and invasion through its role in formation of cellular protrusions such as filopodia and invadopodia. However, the relationship between p53 and Fascin is not understood. Here, we have found a new link between them. In colorectal adenocarcinomas, p53 mutation correlated with high NF-κB, Fascin and low E-cadherin expression. Moreover, this expression profile was shown to contribute to poor overall survival in patients with colorectal cancer. Wild-type p53 could inhibit NF-κB activity that repressed the expression of Fascin and cancer cell invasiveness. In contrast, in p53-deficient primary cultured cells, NF-κB activity was enhanced and then activation of NF-κB increased the expression of Fascin. In further analysis, we showed that NF-κB was a key determinant for p53 deletion-stimulated Fascin expression. Inhibition of NF-κB/p65 expression by pharmacological compound or p65 siRNA suppressed Fascin activity in p53-deficient cells. Moreover, restoration of p53 expression decreased the activation of Fascin through suppression of the NF-κB pathway. Taken together, these data suggest that a negative-feedback loop exists, whereby p53 can suppress colorectal cancer cell invasion by inhibiting the NF-κB-mediated activation of Fascin.

  6. Identification, validation, and targeting of the mutant p53-PARP-MCM chromatin axis in triple negative breast cancer.

    Science.gov (United States)

    Qiu, Wei-Gang; Polotskaia, Alla; Xiao, Gu; Di, Lia; Zhao, Yuhan; Hu, Wenwei; Philip, John; Hendrickson, Ronald C; Bargonetti, Jill

    2017-01-01

    Over 80% of triple negative breast cancers express mutant p53. Mutant p53 often gains oncogenic function suggesting that triple negative breast cancers may be driven by p53 protein type. To determine the chromatin targets of this gain-of-function mutant p53 we used inducible knockdown of endogenous gain-of-function mtp53 in MDA-MB-468 cells in conjunction with stable isotope labeling with amino acids in cell culture and subcellular fractionation. We sequenced over 70,000 total peptides for each corresponding reciprocal data set and were able to identify 3010 unique cytoplasmic fraction proteins and 3403 unique chromatin fraction proteins. The present proteomics experiment corroborated our previous experiment-based results that poly ADP-ribose polymerase has a positive association with mutant p53 on the chromatin. Here, for the first time we report that the heterohexomeric minichromosome maintenance complex that participates in DNA replication initiation ranked as a high mutant p53-chromatin associated pathway. Enrichment analysis identified the minichromosome maintenance members 2-7. To validate this mutant p53- poly ADP-ribose polymerase-minichromosome maintenance functional axis, we experimentally depleted R273H mutant p53 and found a large reduction of the amount of minichromosome maintenance complex proteins on the chromatin. Furthermore a mutant p53-minichromosome maintenance 2 direct interaction was detected. Overexpressed mutant p53, but not wild type p53, showed a protein-protein interaction with minichromosome maintenance 2 and minichromosome maintenance 4. To target the mutant p53- poly ADP-ribose polymerase-minichromosome maintenance axis we treated cells with the poly ADP-ribose polymerase inhibitor talazoparib and the alkylating agent temozolomide and detected synergistic activation of apoptosis only in the presence of mutant p53. Furthermore when minichromosome maintenance 2-7 activity was inhibited the synergistic activation of apoptosis was blocked

  7. Drug-dependent functionalization of wild-type and mutant p53 in cisplatin-resistant human ovarian tumor cells.

    Science.gov (United States)

    Bhatt, Michelle; Ivan, Cristina; Xie, Xiaolei; Siddik, Zahid H

    2016-12-26

    Cisplatin (cis-Pt) resistance in tumor cells from p53 dysfunction is a significant clinical problem. Although mutation can inhibit p53 function, >60% of p53 mutants retain normal function according to literature reports. Therefore, we examined the status of p53 in cisplatin-resistant ovarian tumor models and its functional response to cis-Pt and the mechanistically-distinct non-cross-resistant oxaliplatin (oxali-Pt). Relative to sensitive A2780 cells harboring wild-type p53, the 2780CP/Cl-16, OVCAR-10, Hey and OVCA-433 cell lines were 10- to 30-fold resistant to cis-Pt, but was substantially circumvented by oxali-Pt. Mutant p53 in 2780CP/Cl-16 (p53V172F) and OVCAR-10 (p53V172F and p53G266R) cells, predicted as non-functional in p53 database, displayed attenuated response to cis-Pt, as did the polymorphic p53P72R (functionally equivalent to wild-type p53) in HEY and OVCA-433 cell lines. However, p53 was robustly activated by oxali-Pt in all cell lines, with resultant drug potency confirmed as p53-dependent by p53 knockout using CRISPR/Cas9 system. This p53 activation by oxali-Pt was associated with phosphorylation at Ser20 by MEK1/2 based on inhibitor and kinase studies. Cis-Pt, however, failed to phosphorylate Ser20 due to downregulated Chk2, and its clinical impact validated by reduced overall survival of ovarian cancer patients according to TCGA database. In conclusion, cis-Pt resistance occurs in both wild-type and mutant p53 ovarian cancer cells, but is associated with loss of Ser20 phosphorylation. However, these mutant p53, like polymorphic p53, are functional and activated by oxali-Pt-induced Ser20 phosphorylation. Thus, the potential exists for repurposing oxali-Pt or similar drugs against refractory cancers harboring wild-type or specific mutant p53.

  8. Study of p53 expression and post-transcriptional modifications after GSM-900 radiofrequency exposure of human amniotic cells.

    Science.gov (United States)

    Bourthoumieu, Sylvie; Magnaudeix, Amandine; Terro, Faraj; Leveque, Philippe; Collin, Alice; Yardin, Catherine

    2013-01-01

    The potential effects of radiofrequency (RF) exposure on the genetic material of cells are very important to determine since genome instability of somatic cells may be linked to cancer development. In response to genetic damage, the p53 protein is activated and can induce cell cycle arrest allowing more time for DNA repair or elimination of damaged cells through apoptosis. The objective of this study was to investigate whether the exposure to RF electromagnetic fields, similar to those emitted by mobile phones of the second generation standard, Global System for Mobile Communications (GSM), may induce expression of the p53 protein and its activation by post-translational modifications in cultured human cells. The potential induction of p53 expression and activation by GSM-900 was investigated after in vitro exposure of human amniotic cells for 24 h to average specific absorption rates (SARs) of 0.25, 1, 2, and 4 W/kg in the temperature range of 36.3-39.7 °C. The exposures were carried out using a wire-patch cell (WPC) under strictly controlled conditions of temperature. Expression and activation of p53 by phosphorylation at serine 15 and 37 were studied using Western blot assay immediately after three independent exposures of cell cultures provided from three different donors. Bleomycin-exposed cells were used as a positive control. According to our results, no significant changes in the expression and activation of the p53 protein by phosphorylation at serine 15 and 37 were found following exposure to GSM-900 for 24 h at average SARs up to 4 W/kg in human embryonic cells.

  9. Quercetin Potentiates Doxorubicin Mediated Antitumor Effects against Liver Cancer through p53/Bcl-xl

    Science.gov (United States)

    Wang, Guanyu; Sharma, Sherven; Dong, Qinghua

    2012-01-01

    Background The dose-dependent toxicities of doxorubicin (DOX) limit its clinical applications, particularly in drug-resistant cancers, such as liver cancer. In this study, we investigated the role of quercetin on the antitumor effects of DOX on liver cancer cells and its ability to provide protection against DOX-mediated liver damage in mice. Methodology and Results The MTT and Annexin V/PI staining assay demonstrated that quercetin selectively sensitized DOX-induced cytotoxicity against liver cancer cells while protecting normal liver cells. The increase in DOX-mediated apoptosis in hepatoma cells by quercetin was p53-dependent and occurred by downregulating Bcl-xl expression. Z-VAD-fmk (caspase inhibitor), pifithrin-α (p53 inhibitor), or overexpressed Bcl-xl decreased the effects of quercetin on DOX-mediated apoptosis. The combined treatment of quercetin and DOX significantly reduced the growth of liver cancer xenografts in mice. Moreover, quercetin decreased the serum levels of alanine aminotransferase and aspartate aminotransferase that were increased in DOX-treated mice. Quercetin also reversed the DOX-induced pathological changes in mice livers. Conclusion and Significance These results indicate that quercetin potentiated the antitumor effects of DOX on liver cancer cells while protecting normal liver cells. Therefore, the development of quercetin may be beneficial in a combined treatment with DOX for increased therapeutic efficacy against liver cancer. PMID:23240061

  10. Expanding the prion concept to cancer biology: dominant-negative effect of aggregates of mutant p53 tumour suppressor

    OpenAIRE

    2013-01-01

    p53 is a key protein that participates in cell-cycle control, and its malfunction can lead to cancer. This tumour suppressor protein has three main domains; the N-terminal transactivation domain, the CTD (C-terminal domain) and the core domain (p53C) that constitutes the sequence-specific DBD (DNA-binding region). Most p53 mutations related to cancer development are found in the DBD. Aggregation of p53 into amyloid oligomers and fibrils has been shown. Moreover, amyloid aggregates of both the...

  11. Inhibition of Thr-55 phosphorylation restores p53 nuclear localization and sensitizes cancer cells to DNA damage.

    Science.gov (United States)

    Cai, Xin; Liu, Xuan

    2008-11-04

    The p53 tumor suppressor induces cell growth arrest and apoptosis in response to DNA damage. Because these functions are achieved largely by the transcriptional properties of p53, nuclear localization of the protein is essential. Indeed, the tumors with aberrant cytoplasmic localization of wild-type p53 often exhibit an impaired response to DNA damage. In this study, we report that Thr-55 phosphorylation induces the association of p53 with the nuclear export factor CRM1, leading to p53 nuclear export. We further show that MDM2 also promotes the CRM1-p53 association and Thr-55 phosphorylation is required for this process. Interestingly, inhibition of Thr-55 phosphorylation by a dietary flavonoid, apigenin, specifically blocks the CRM1-p53 association, restores p53 nuclear localization, and sensitizes tumor cells with cytoplasm localized wild-type p53 to DNA damage. These data provide insights into the regulation of p53 nuclear localization by post-translational modification and suggest an avenue for targeted therapy for cancers caused by aberrant cytoplasm localization of wild-type p53.

  12. Immunohistochemical detection of mutant p53 protein in small-cell lung cancer: relationship to treatment outcome.

    Science.gov (United States)

    Gemba, K; Ueoka, H; Kiura, K; Tabata, M; Harada, M

    2000-07-01

    We investigated the expression of mutant p53 proteins in small-cell lung cancer (SCLC) immunohistochemically, by identification of stabilized mutant p53 proteins with a much longer half-life than the wild-type protein. Of 103 tumor specimens obtained by transbronchial tumor biopsy for histologic diagnosis, 52 (50%) showed positive staining for p53 protein with a p53 monoclonal antibody, DO-1. Positive staining for p53 protein was not correlated with age, sex, performance status, lifetime cigarette consumption, serum concentration of neuron-specific enolase and extent of disease. Complete response rates in patients with a mutant p53 protein-positive tumor were significantly lower than those in p53-negative patients (25% versus 59%; P=0.0005, by chi-square test). Similarly, survival periods in patients with a mutant p53 protein-positive tumor were significantly shorter than those in mutant p53-protein-negative patients (10.8 months versus 20.6 months; P=0.0001, by generalized Wilcoxon test). Multivariate analysis using Cox's proportional hazards model revealed that the presence of mutant p53 protein is an independent factor associated with differences in overall survival (hazards ratio=2.72; 95% confidence interval, 1.71-4.34; P=0.0001). These observations suggest that the expression of mutant p53 proteins in SCLC may be an important factor predicting poor prognosis.

  13. Transient p53 Suppression Increases Reprogramming of Human Fibroblasts without Affecting Apoptosis and DNA Damage

    Directory of Open Access Journals (Sweden)

    Mikkel A. Rasmussen

    2014-09-01

    Full Text Available The discovery of human-induced pluripotent stem cells (iPSCs has sparked great interest in the potential treatment of patients with their own in vitro differentiated cells. Recently, knockout of the Tumor Protein 53 (p53 gene was reported to facilitate reprogramming but unfortunately also led to genomic instability. Here, we report that transient suppression of p53 during nonintegrative reprogramming of human fibroblasts leads to a significant increase in expression of pluripotency markers and overall number of iPSC colonies, due to downstream suppression of p21, without affecting apoptosis and DNA damage. Stable iPSC lines generated with or without p53 suppression showed comparable expression of pluripotency markers and methylation patterns, displayed normal karyotypes, contained between 0 and 5 genomic copy number variations and produced functional neurons in vitro. In conclusion, transient p53 suppression increases reprogramming efficiency without affecting genomic stability, rendering the method suitable for in vitro mechanistic studies with the possibility for future clinical translation.

  14. Anti-cancer activity of trans-chalcone in osteosarcoma: Involvement of Sp1 and p53.

    Science.gov (United States)

    Silva, Gabriel; Marins, Mozart; Fachin, Ana Lúcia; Lee, Seong-Ho; Baek, Seung Joon

    2016-10-01

    Osteosarcoma is the most common bone cancer. Although the emergence of multidrug therapies has improved available treatments for osteosarcoma, approximately 30% of patients will still develop metastasis. Currently, much anticancer therapy uses drugs that affect oncogenes/tumor suppressor genes, such as p53 (up-regulation) and Sp1 (down-regulation). Chalcones are secondary metabolites of plants and have been demonstrated to induce apoptosis in human cancer cells. Building on this knowledge, we evaluated the ability of trans-chalcone to reduce viability, to induce apoptosis, and to alter gene expression of p53 and Sp1 in human osteosarcoma cell lines. We found that treatment of trans-chalcone inhibited growth of osteosarcoma cells in a dose- and time-dependent manner, with significant inhibition at 10 μM after 48 h; apoptosis was also induced in a dose-dependent manner, with 1.9- and 3.6-fold induction at 10 μM and 50 μM, respectively, compared to non-treated cells. Further experiments suggest that trans-chalcone affected Sp1 down-regulation at the transcriptional level, whereas trans-chalcone up-regulated p53 expression at the post-translational level. trans-chalcone and its derivatives could be important in the development of future clinical trials in osteosarcoma. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. Immunologic aspect of ovarian cancer and p53 as tumor antigen

    Directory of Open Access Journals (Sweden)

    van der Burg SH

    2005-09-01

    Full Text Available Abstract Ovarian cancer represents the fifth leading cause of death from all cancers for women. During the last decades overall survival has improved due to the use of new chemotherapy schedules. Still, the majority of patients die of this disease. Research reveals that ovarian cancer patients exhibit significant immune responses against their tumor. In this review the knowledge obtained thus far on the interaction of ovarian cancer tumor cells and the immune system is discussed. Furthermore the role of p53 as tumor antigen and its potential role as target antigen in ovarian cancer is summarized. Based on the increased knowledge on the role of the immune system in ovarian cancer major improvements are to be expected of immunotherapy based treatment of this disease.

  16. Anti-cancer efficacy of SREBP inhibitor, alone or in combination with docetaxel, in prostate cancer harboring p53 mutations.

    Science.gov (United States)

    Li, Xiangyan; Wu, Jason Boyang; Chung, Leland W K; Huang, Wen-Chin

    2015-12-01

    Mutant p53 proteins (mutant p53s) have oncogenic gain-of-function properties correlated with tumor grade, castration resistance, and prostate cancer (PCa) tumor recurrence. Docetaxel is a standard first-line treatment for metastatic castration-resistant PCa (mCRPC) after the failure of hormone therapy. However, most mCRPC patients who receive docetaxel experience only transient benefits and rapidly develop incurable drug resistance, which is closely correlated with the p53 mutation status. Mutant p53s were recently reported to regulate the metabolic pathways via sterol regulatory element-binding proteins (SREBPs). Therefore, targeting the SREBP metabolic pathways with docetaxel as a combination therapy may offer a potential strategy to improve anti-tumor efficacy and delay cellular drug resistance in mCRPC harboring mutant p53s. Our previous data showed that fatostatin, a new SREBP inhibitor, inhibited cell proliferation and induced apoptosis in androgen receptor (AR)-positive PCa cell lines and xenograft mouse models. In this study, we demonstrated that mutant p53s activate the SREBP-mediated metabolic pathways in metastatic AR-negative PCa cells carrying mutant p53s. By blocking the SREBP pathways, fatostatin inhibited cell growth and induced apoptosis in metastatic AR-negative PCa cells harboring mutant p53s. Furthermore, the combination of fatostatin and docetaxel resulted in greater proliferation inhibition and apoptosis induction compared with single agent treatment in PCa cells in vitro and in vivo, especially those with mutant p53s. These data suggest for the first time that fatostatin alone or in combination with docetaxel could be exploited as a novel and promising therapy for metastatic PCa harboring p53 mutations.

  17. The oncoprotein HBXIP modulates the feedback loop of MDM2/p53 to enhance the growth of breast cancer.

    Science.gov (United States)

    Li, Hang; Liu, Qian; Wang, Zhen; Fang, Runping; Shen, Yu; Cai, Xiaoli; Gao, Yuen; Li, Yinghui; Zhang, Xiaodong; Ye, Lihong

    2015-09-11

    MDM2 and p53 form a negative feedback loop, in which p53 as a transcription factor positively regulates MDM2 and MDM2 negatively regulates tumor suppressor p53 through promoting its degradation. However, the mechanism of the feedback loop is poorly understood in cancers. We had reported previously that the oncoprotein hepatitis B X-interacting protein (HBXIP) is a key oncoprotein in the development of cancer. Thus, we supposed that HBXIP might be involved in the event. Here, we observed that the expression levels of HBXIP were positively correlated to those of MDM2 in clinical breast cancer tissues. Interestingly, HBXIP was able to up-regulate MDM2 at the levels of mRNA and protein in MCF-7 breast cancer cells. Mechanically, HBXIP increased the promoter activities of MDM2 through directly binding to p53 in the P2 promoter of MDM2. Strikingly, we identified that the acetyltransferase p300 was recruited by HBXIP to p53 in the promoter of MDM2. Moreover, we validated that HBXIP enhanced the p53 degradation mediated by MDM2. Functionally, the knockdown of HBXIP or/and p300 inhibited the proliferation of breast cancer cells in vitro, and the depletion of MDM2 or overexpression of p53 significantly blocked the HBXIP-promoted growth of breast cancer in vitro and in vivo. Thus, we concluded that highly expressed HBXIP accelerates the MDM2-mediated degradation of p53 in breast cancer through modulating the feedback loop of MDM2/p53, resulting in the fast growth of breast cancer cells. Our findings provide new insights into the mechanism of the acceleration of the MDM2/p53 feedback loop in the development of cancer.

  18. The Clinical Significance of Cathepsin D and p53 Expression in Locally Advanced Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jun-Sang; Lee, Sheng-Jin; Kim, Jin-Man; Cho, Moon-June [Chungnam National University, Daejeon (Korea, Republic of)

    2008-03-15

    Cathepsin D (CD) is a lysosomal acid proteinase that is related to malignant progression, invasion, and a poor prognosis in several tumors. The aim of this study was to evaluate the prognostic clinical significance of CD and p53 expression in pretreatment biopsy specimens from patients with locally advanced rectal cancer who were treated with preoperative chemoradiation. Eighty-nine patients with locally advanced rectal cancer (cT3/T4 or N+) were included in this study. Preoperative chemoradiation consisted of a dose of 50.4 Gy of pelvic radiation and two concurrent cycles of administration of 5-fluorouracil and leucovorin. Surgery was performed six weeks after chemoradiation. CD and p53 expression in pretreatment formalin-fixed paraffin-embedded tumor biopsy specimens were assessed by immunohistochemical staining using a CD and p53 monoclonal antibodies. The threshold value for a positive stain in tumor tissue and stromal cells was 1+ intensity in 10% of the tumors or stromal cells, respectively. Positive CD expression was found in 57 (64%) of the tumors and 32 (35%) of the stromal cell specimens. There was no association with CD expression of the tumor or stromal cells and patient characteristics. There was a correlation between tumor CD expression with stromal cell CD expression (p=0.01). Overexpression of p53 was not a significant prognostic factor. The 5-year overall survival (OS) and disease-free survival (DFS) rates were not different between tumor CD-negative and positive patient biopsy samples (69% vs. 65%, 60% vs. 61%, respectively). The 5-year OS rates in the tumor-negative/stromal cell-negative, tumor-negative/stromal cell-positive, tumor-positive/stromal cell-negative and tumor-positive/ stromal cell-positive biopsy samples were 75%, 28%, 62%, and 73%, respectively. Stromal cell staining only without positive tumor staining demonstrated the worst overall survival prognosis for patients (p=0.013). Overexpression of p53 in rectal biopsy tissue was not

  19. Evodiamine selectively targets cancer stem-like cells through the p53-p21-Rb pathway

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seula [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Woo, Jong Kyu [College of Pharmacy, Gachon University, Incheon (Korea, Republic of); Jung, Yuchae; Jeong, Dawoon; Kang, Minsook; Yoo, Young-Ji; Lee, Hani [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Oh, Seung Hyun [College of Pharmacy, Gachon University, Incheon (Korea, Republic of); Ryu, Jae-Ha [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of); Kim, Woo-Young, E-mail: wykim@sookmyung.ac.kr [The Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul (Korea, Republic of)

    2016-01-22

    In spite of the recent improvements, the resistance to chemotherapy/radiotherapy followed by relapse is the main hurdle for the successful treatment of breast cancer, a leading cause of death in women. A small population of breast cancer cells that have stem-like characteristics (cancer stem-like cells; CSLC) may contribute to this resistance and relapse. Here, we report on a component of a traditional Chinese medicine, evodiamine, which selectively targets CSLC of breast cancer cell lines MCF7 and MDAMB 231 at a concentration that does show a little or no cytotoxic effect on bulk cancer cells. While evodiamine caused the accumulation of bulk cancer cells at the G2/M phase, it did not hold CSLC in a specific cell cycle phase but instead, selectively killed CSLC. This was not due to the culture of CSLC in suspension or without FBS. A proteomic analysis and western blotting revealed that evodiamine changed the expression of cell cycle regulating molecules more efficiently in CSLC cells than in bulk cancer cells. Surprisingly, evodiamine selectively activated p53 and p21 and decreased inactive Rb, the master molecules in G1/S checkpoint. These data collectively suggest a novel mechanism involving CSLC-specific targeting by evodiamine and its possible use to the therapy of breast cancer. - Highlights: • Evodiamine selectively kills breast cancer stem like cells at G1 phase. • Evodiamine utilizes different mechanism of cell cycle modulation in CSLC and in bulk cancer cells. • Evodiamine activate the p53, p21 and Rb pathway.

  20. Bisindole-PBD regulates breast cancer cell proliferation via SIRT-p53 axis.

    Science.gov (United States)

    Sarma, Pranjal; Bag, Indira; Ramaiah, M Janaki; Kamal, Ahmed; Bhadra, Utpal; Pal Bhadra, Manika

    2015-01-01

    In a previous study we reported the role of potent bisindole-PBD conjugate as an inclusion in the arsenal of breast cancer therapeutics. In breast cancer cell proliferation, PI3K/AKT/mTOR pathway plays a crucial role by prosurvival mechanism that inhibits programmed cell death. Here, 2 breast cancer cells lines, MCF-7 and MDA-MB-231 were treated with Vorinostat (suberoylanilide hydroxamic acid / SAHA) and bisindole-PBD (5b). We have investigated the effect on PI3K/AKT/mTOR pathway and SIRT expression including epigenetic regulation. There was consistent decrease in the level of PI3K, AKT, mTOR proteins upon treatment of 5b in both MCF-7 and MDA-MB-231 cell lines compared to untreated controls. Treatment with caspase inhibitor (Q-VD-OPH) confirmed that the effect of 5b on PI3K signaling was ahead of apoptosis. Real time PCR and western blot analysis showed profound reduction in the mRNA and protein levels of SIRT1 and SIRT2. Molecular docking studies also supported the interaction of 5b with various amino acids of SIRT2 proteins. Treatment with 5b caused epigenetic changes that include increase of acetylated forms of p53, increase of histone acetylation at p21 promoter as well as decrease in methylation state of p21 gene. Compound 5b thus acts as SIRT inhibitor and cause p53 activation via inhibition of growth factor signaling and activation of p53 dependent apoptotic signaling. This present study focuses bisindole-PBD on epigenetic alteration putting 5b as a promising therapeutic tool in the realm of breast cancer research.

  1. Combining p53 stabilizers with metformin induces synergistic apoptosis through regulation of energy metabolism in castration-resistant prostate cancer.

    Science.gov (United States)

    Chen, Long; Ahmad, Nihal; Liu, Xiaoqi

    2016-01-01

    Since altered energy metabolism is a hallmark of cancer, many drugs targeting metabolic pathways are in active clinical trials. The tumor suppressor p53 is often inactivated in cancer, either through downregulation of protein or loss-of-function mutations. As such, stabilization of p53 is considered as one promising approach to treat those cancers carrying wild type (WT) p53. Herein, SIRT1 inhibitor Tenovin-1 and polo-like kinase 1 (Plk1) inhibitor BI2536 were used to stabilize p53. We found that both Tennovin-1 and BI2536 increased the anti-neoplastic activity of metformin, an inhibitor of oxidative phosphorylation, in a p53 dependent manner. Since p53 has also been shown to regulate metabolic pathways, we further analyzed glycolysis and oxidative phosphorylation upon drug treatments. We showed that both Tennovin-1 and BI2536 rescued metformin-induced glycolysis and that both Tennovin-1 and BI2536 potentiated metformin-associated inhibition of oxidative phosphorylation. Of significance, castration-resistant prostate cancer (CRPC) C4-2 cells show a much more robust response to the combination treatment than the parental androgen-dependent prostate cancer LNCaP cells, indicating that targeting energy metabolism with metformin plus p53 stabilizers might be a valid approach to treat CRPC carrying WT p53.

  2. Immunohistochemical Assessment of O(6)-Methylguanine-DNA Methyltransferase (MGMT) and Its Relationship with p53 Expression in Endometrial Cancers.

    Science.gov (United States)

    Lee, Kyung Eun

    2013-12-01

    O(6)-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.

  3. Mutations of the p53 gene in human functional adrenal neoplasms

    Energy Technology Data Exchange (ETDEWEB)

    Shiu-Ru Lin; Yau-Jiunn Lee; Juei-Hsiung Tsai [Kaohsiung Medical College, Taiwan (China)

    1994-02-01

    To clarify gene alterations in functional human adrenal tumors, the authors performed molecular analysis for p53 abnormalities in 23 cases with adrenal neoplasms. The immunohistochemical study with anti-p53 monoclonal antibody pAb1801 demonstrated that 10 of 23 (43.5%) cases overexpressed p53 protein in the tumor cells. Using a polymerase chain reaction-single strand conformation polymorphism study, 5 of 6 (83.3%) pheochromocytoma tissues (1 malignant and 5 benign) and 11 of 15 (73.3%) adrenocortical adenomas (2 with Cushing`s syndrome and 13 with primary aldosteronism, all benign) showed an apparent electrophoretic mobility shift between the tumor and its paired adjacent normal adrenal tissue. Such differences were detected in exon 4 (12 cases), exon 5 (2 cases), and exon 7 (3 cases). The types of these mutations in exon 4 were a substitution from threonine (ACC) to isoleucine (ATC) at codon 102 in 5 cases, from glutamine (CAG) to histidine (CAC) at codon 104 in 1 case, from glycine (GGG) to alanine (CGG) at codon 117 in 1 case, from glutamate (GAG) to glutamine (CAG) at codon 68 in 1 case, and single base changes resulting in a premature stop codon at codon 100 in 2 cases. A 2-basepair deletion at codon 175 in exon 5 resulting in a frame shift was identified in 1 case. A single point mutation was identified, resulting in the substitution of glutamine (CAG) for arginine (CGG) at codon 248 of exon 7 in 1 case. A single basepair deletion at codon 249 resulted in a frame shift in 2 cases. There was 1 case with malignant pheochromocytoma that combined a single point mutation in exon 4 and a single base deletion in exon 7. Only 2 of 23 cases showed a loss of a normal allele encoding in the p53 gene. Northern blot analysis with 1.8-kilobase p53 cDNA revealed that p53 mRNA was overexpressed in 6 cases. The results indicate that high frequencies of p53 gene mutation, especially in exon 4, exist in functional adrenal tumors. 39 refs., 6 figs., 4 tabs.

  4. p53和基质金属蛋白酶-2在胃癌组织中的表达及意义%Expressions of p53 and matrix metalloproteinase-2 in gastric cancer tissue

    Institute of Scientific and Technical Information of China (English)

    罗浩; 李力; 潘晟

    2014-01-01

    目的 通过量子点(QDs)即新型半导体免疫荧光标记试剂结合组织芯片技术检测p53及基质金属蛋白酶-2(MMP-2)蛋白在人胃癌组织中的表达,并与免疫酶组织化学法比较,探讨免疫荧光组织化学试剂量子点技术的有效性和实用性.方法 采用半导体免疫荧光标记试剂-量子点结合组织芯片技术(QDs-IHC)观察人胃癌组织芯片中p53及MMP-2蛋白的表达,并且检测p53及MMP-2蛋白在胃癌组织中的共表达,并与常规免疫酶法的结果比较.结果 新型QDs-IHC和常规的免疫组织化学(IHC)法检测分析显示:p53(胃癌组p53蛋白两种方法的阳性检测率分别为72.86%和65.71%)及MMP-2蛋白(胃癌组:MMP-2蛋白两种方法检测的阳性率为87.14%和82.86%)表达在对照组和胃癌组之间比较,差异有统计学意义(P<0.05).p53及MMP-2蛋白表达之间呈显著正相关(r =0.533,P<0.01).QDs-IHC检测2种蛋白表达的阳性率均高于IHC所检测的结果,但差异无统计学意义(P>0.05).结论 新型QDs-IHC和常规IHC两种方法可检测到p53及MMP-2蛋白在胃癌组织中的表达,QDs-IHC技术检测其灵敏度比IHC高,图片显色背景比IHC干净.p53及MMP-2在胃癌患者的癌组织中共同表达.%Objective In this experiment we used quantum dots (QDs) by new type of semiconductor immunofluorescence labeling reagents combined with tissue chip technology to detect p53 and matrix metalloproteinase (MMP)-2 protein expression in gastric cancer tissue of the situation,and compared with the immune enzyme network stations,the immunofluorescence histochemical reagent validity and practicability of the quantum dots.Immunofluorescence histochemical.Methods Quantum dots immunohistochemistry (QDs-IHC) and p53 in human gastric cancer tissue microarray technology analysis and the expression of MMP-2 protein,and also tested the p53 and MMP-2 protein expression in the tissue of gastric cancer were,and compared with the conventional

  5. 胆囊癌及胆囊腺瘤中p53蛋白异常表达的研究%On the Overexpression of Gall Biadder Cancer and p53 Protein Adenoma

    Institute of Scientific and Technical Information of China (English)

    梁喜林; 尹继云; 赵红

    2003-01-01

    Objective To inviestigate the expression of gall bladder cancer and its relationship with canceration.Methods Immunohistochemistry techniques are used to detect the expression of p53 protein in 36 cases of gall bladder cancer and 23 adenoma.Results p53 protein were founded positive in 19 cases (52.78%)of gall blodder cancer,in 5 cases (21.74%)of adenoma.Conclusion There is close relationship between the over expression and the canceration of gall bladder.p53 gene mutation and over expression are in the early stage of gall bladder cancer,and play an important role in the canceration of adenoma.

  6. Mutant p53 promotes ovarian cancer cell adhesion to mesothelial cells via integrin β4 and Akt signals.

    Science.gov (United States)

    Lee, Jong-Gyu; Ahn, Ji-Hye; Jin Kim, Tae; Ho Lee, Jae; Choi, Jung-Hye

    2015-07-30

    Missense mutations in the TP53 gene resulting in the accumulation of mutant proteins are extremely common in advanced ovarian cancer, which is characterised by peritoneal metastasis. Attachment of cancer cells to the peritoneal mesothelium is regarded as an initial, key step for the metastatic spread of ovarian cancer. In the present study, we investigated the possible role of a p53 mutant in the mesothelial adhesion of ovarian cancer cells. We found that OVCAR-3 cells with the R248 TP53 mutation (p53(R248)) were more adhesive to mesothelial Met5A cells than were A2780 cells expressing wild-type p53. In addition, ectopic expression of p53(R248) in p53-null SKOV-3 cells significantly increased adhesion to Met5A cells. Knockdown of mutant p53 significantly compromised p53(R248)-induced cell adhesion to Met5A cells. Microarray analysis revealed that several adhesion-related genes, including integrin β4, were markedly up-regulated, and certain signalling pathways, including PI3K/Akt, were activated in p53(R248) transfectants of SKOV-3 cells. Inhibition of integrin β4 and Akt signalling using blocking antibody and the inhibitor LY294002, respectively, significantly attenuated p53(R248)-mediated ovarian cancer-mesothelial adhesion. These data suggest that the p53(R248) mutant endows ovarian cancer cells with increased adhesiveness and that integrin β4 and Akt signalling are associated with the mutation-enhanced ovarian cancer-mesothelial cell adhesion.

  7. Restoring apoptosis as a strategy for cancer gene therapy: focus on p53 and mda-7.

    Science.gov (United States)

    Lebedeva, Irina V; Su, Zhao Zhong; Sarkar, Devanand; Fisher, Paul B

    2003-04-01

    Understanding the molecular and genetic determinants of cancer will provide unique opportunities for developing rational and effective therapies. Malignant cells are frequently resistant to chemotherapy and radiation induced programmed cell death (apoptosis). This resistance can occur by mutations in the tumor suppressor gene p53. Strategies designed to replace this defective tumor suppressor protein, as well as forced expression of a novel cancer specific apoptosis inducing gene, melanoma differentiation associated gene-7 (mda-7), offer promise for restoring apoptosis in tumor cells. Conditional-replicating viruses that selectively induce cytolysis in tumor cells provides an additional means of targeting cancer cells for destruction. Although these approaches represent works in progress, future refinements will in all likelihood result in the next generation of cancer therapies.

  8. LC-MS/MS-based targeted proteomics quantitatively detects the interaction between p53 and MDM2 in breast cancer.

    Science.gov (United States)

    Zhang, Wen; Zhong, Ting; Chen, Yun

    2017-01-30

    In breast cancer, p53 could be functionally compromised by interaction with several proteins. Among those proteins, MDM2 serves as a pivotal negative regulator and counteracts p53 activation. Thus, the ability to quantitatively and accurately monitor the changes in level of p53-MDM2 interaction with disease state can enable an improved understanding of this protein-protein interaction (PPI), provide a better insight into cancer development and allow the emergence of advanced treatments. However, rare studies have evaluated the quantitative extent of PPI including p53-MDM2 interaction so far. In this study, a LC-MS/MS-based targeted proteomics assay was developed and coupled with co-immunoprecipitation (Co-IP) for the quantification of p53-MDM2 complex. A p53 antibody with the epitope residing at 156-214 residues achieved the greatest IP efficiency. 321KPLDGEYFTLQIR333 (p53) and 327ENWLPEDK334 (MDM2) were selected as surrogate peptides in the targeted analysis. Stable isotope-labeled synthetic peptides were used as internal standards. An LOQ (limit of quantification) of 2ng/mL was obtained. Then, the assay was applied to quantitatively detect total p53, total MDM2 and p53-MDM2 in breast cells and tissue samples. Western blotting was performed for a comparison. Finally, a quantitative time-course analysis in MCF-7 cells with the treatment of nutlin-3 as a PPI inhibitor was also monitored.

  9. A Cohort Study of p53 Mutations and Protein Accumulation in Benign Breast Tissue and Subsequent Breast Cancer Risk.

    Science.gov (United States)

    Kabat, Geoffrey C; Kandel, Rita A; Glass, Andrew G; Jones, Joan G; Olson, Neal; Duggan, Catherine; Ginsberg, Mindy; Negassa, Abdissa; Rohan, Thomas E

    2011-01-01

    Mutations in the p53 tumor suppressor gene and accumulation of its protein in breast tissue are thought to play a role in breast carcinogenesis. However, few studies have prospectively investigated the association of p53 immunopositivity and/or p53 alterations in women with benign breast disease in relation to the subsequent risk of invasive breast cancer. We carried out a case-control study nested within a large cohort of women biopsied for benign breast disease in order to address this question. After exclusions, 491 breast cancer cases and 471 controls were available for analysis. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). Neither p53 immunopositivity nor genetic alterations in p53 (either missense mutations or polymorphisms) was associated with altered risk of subsequent breast cancer. However, the combination of both p53 immunopositivity and any p53 nucleotide change was associated with an approximate 5-fold nonsignificant increase in risk (adjusted OR 4.79, 95% CI 0.28-82.31) but the confidence intervals were extremely wide. Our findings raise the possibility that the combination of p53 protein accumulation and the presence of genetic alterations may identify a group at increased risk of breast cancer.

  10. A Cohort Study of p53 Mutations and Protein Accumulation in Benign Breast Tissue and Subsequent Breast Cancer Risk

    Directory of Open Access Journals (Sweden)

    Geoffrey C. Kabat

    2011-01-01

    Full Text Available Mutations in the p53 tumor suppressor gene and accumulation of its protein in breast tissue are thought to play a role in breast carcinogenesis. However, few studies have prospectively investigated the association of p53 immunopositivity and/or p53 alterations in women with benign breast disease in relation to the subsequent risk of invasive breast cancer. We carried out a case-control study nested within a large cohort of women biopsied for benign breast disease in order to address this question. After exclusions, 491 breast cancer cases and 471 con