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Sample records for breast overexpress p53

  1. Mutations in p53, p53 protein overexpression and breast cancer survival

    Czech Academy of Sciences Publication Activity Database

    Rössner ml., Pavel; Gammon, M. D.; Zhang, Y.J.; Terry, M. B.; Hibshoosh, H.; Memeo, L.; Mansukhani, M.; Long, CH.M.; Gabrowski, G.; Agrawal, M.; Kalra, T.S.; Teitelbaum, S. L.; Neugut, A. I.; Santella, R. M.

    2009-01-01

    Roč. 13, č. 9B (2009), s. 3847-3857 ISSN 1582-1838 Institutional research plan: CEZ:AV0Z50390512 Keywords : Breast cancer * p53 mutations * Survival Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 5.228, year: 2009

  2. Overexpression of p53 in Nigerian breast cancers and its ...

    African Journals Online (AJOL)

    This study sought to determine the expression of p53 protein as well as the relationship with oestrogen receptor (ER) and progesterone receptor (PR) proteins. Methodology: Formalin-fixed, paraffin-embedded tissue samples of diagnosed invasive breast cancer were obtained from the Department of Anatomic and ...

  3. Overexpressed ubiquitin ligase Cullin7 in breast cancer promotes cell proliferation and invasion via down-regulating p53

    International Nuclear Information System (INIS)

    Guo, Hongsheng; Wu, Fenping; Wang, Yan; Yan, Chong; Su, Wenmei

    2014-01-01

    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

  4. 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.

  5. 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

    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

  6. Estrogen receptor positive breast tumors resist chemotherapy by the overexpression of P53 in Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Fatma Ashour

    2018-06-01

    Full Text Available Background and Objectives: Breast cancer (BC is classified according to estrogen receptor (ER status into ER+ and ER− tumors. ER+ tumors have a worse response to chemotherapy compared to ER− tumors. BCL-2, TP53, BAX and NF-ΚB are involved in drug resistance in the ER+ tumors. Recently it was shown that Cancer Stem Cells (CSCs play an important role in drug resistance. In this study we tested the hypothesis that CSCs of the ER+ tumors resist drug through the overexpression of BCL-2, TP53, BAX and NF-ΚB. Methods: CSCs were isolated by anoikis resistance assay from MCF7 (ER+ and MDA-MB-231 (ER− cell lines. Isolated CSCs were treated with doxorubicin (DOX and the mRNA expression levels of BCL-2, TP53, BAX and NFKB were investigated by quantitative real time PCR (qPCR with and without treatment. Results: BCL-2, BAX and NF-ΚB showed decreased expression in MCF7 bulk cancer cells after DOX treatment whereas only BCL-2 and BAX showed decreased expression in MDA-MB-231 bulk cancer cells. Interestingly TP53 was the only gene showed a considerable increase in its expression in CSCs of the ER+ MCF7 cell line compared to bulk cancer cells. Moreover, TP53 was the only gene showing exceptionally higher level of expression in MCF7-CSCs compared to MDA-MB-231-CSCs. Conclusion: Our results suggest that CSCs in the ER+ cells escape the effect of DOX treatment by the elevation of p53 expression. Keywords: Breast cancer, Cancer Stem Cells, Drug resistance, Estrogen receptors

  7. Tobacco, alcohol, and p53 overexpression in early colorectal neoplasia

    International Nuclear Information System (INIS)

    Terry, Mary Beth; Neugut, Alfred I; Mansukhani, Mahesh; Waye, Jerome; Harpaz, Noam; Hibshoosh, Hanina

    2003-01-01

    The p53 tumor suppressor gene is commonly mutated in colorectal cancer. While the effect of p53 mutations on colorectal cancer prognosis has been heavily studied, less is known about how epidemiologic risk factors relate to p53 status, particularly in early colorectal neoplasia prior to clinically invasive colorectal cancer (including adenomas, carcinoma in situ (CIS), and intramucosal carcinoma). We examined p53 status, as measured by protein overexpression, in 157 cases with early colorectal neoplasia selected from three New York City colonoscopy clinics. After collecting paraffin-embedded tissue blocks, immunohistochemistry was performed using an anti-p53 monoclonal mouse IgG 2 a [BP53-12-1] antibody. We analyzed whether p53 status was different for risk factors for colorectal neoplasia relative to a polyp-free control group (n = 508). p53 overexpression was found in 10.3%, 21.7%, and 34.9%, of adenomatous polyps, CIS, and intramucosal cases, respectively. Over 90% of the tumors with p53 overexpression were located in the distal colon and rectum. Heavy cigarette smoking (30+ years) was associated with cases not overexpressing p53 (OR = 1.8, 95% CI = 1.1–2.9) but not with those cases overexpressing p53 (OR = 1.0, 95% CI = 0.4–2.6). Heavy beer consumption (8+ bottles per week) was associated with cases overexpressing p53 (OR = 4.0, 95% CI = 1.3–12.0) but not with cases without p53 overexpression (OR = 1.6, 95% CI = 0.7–3.7). Our findings that p53 overexpression in early colorectal neoplasia may be positively associated with alcohol intake and inversely associated with cigarette smoking are consistent with those of several studies of p53 expression and invasive cancer, and suggest that there may be relationships of smoking and alcohol with p53 early in the adenoma to carcinoma sequence

  8. P53 Gene Mutagenesis in Breast Cancer

    National Research Council Canada - National Science Library

    Sommer, Steve S

    2005-01-01

    .... The central hypothesis of this proposal is that variability in the patterns of p53 mutagensis in breast cancer reflects differences in exposures to different amounts and/or types of diverse environmental mutagens...

  9. Associations between Polycyclic Aromatic Hydrocarbon-Related Exposures and p53 Mutations in Breast Tumors

    Czech Academy of Sciences Publication Activity Database

    Mordukhovich, I.; Rössner ml., Pavel; Terry, M. B.; Santella, R.; Zhang, Y.J.; Hibshoosh, H.; Memeo, L.; Mansukhani, M.; Long, CH.M.; Garbowski, G.; Agrawal, M.; Gaudet, M. M.; Steck, S. E.; Sagiv, S. K.; Eng, S. M.; Teitelbaum, S. L.; Neugut, A. I.; Conway-Dorsey, K.; Gammon, M. D.

    2010-01-01

    Roč. 118, č. 4 (2010), s. 511-518 ISSN 0091-6765 Institutional research plan: CEZ:AV0Z50390512 Keywords : breast cancer * p53 mutation * p53 overexpression Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 6.087, year: 2010

  10. P53 overexpression and outcome of radiation therapy in head and neck cancers

    International Nuclear Information System (INIS)

    Kim, In Ah; Choi, Ihl Bhong; Kang, Ki Mun; Jang, Ji Young; Kim, Kyung Mi; Park, Kyung Shin; Kim, Young Shin; Kang, Chang Suk; Cho, Seung Ho; Kim, Hyung Tae

    1999-01-01

    Experimental studies have implicated the wild type p53 in cellular response to radiation. Whether altered p53 function can lead to changes in clinical radiocurability remains an area of ongoing study. This study was performed to investigate whether any correlation between change of p53 and outcome of curative radiation therapy in patients with head and neck cancers. Immunohistochemical analysis with a mouse monoclonal antibody (D0-7) specific for human p53 was used to detect to overexpression of protein in formalin fixed, paraffin-embedded tumor sample from 55 head and neck cancer patients treated with curative radiation therapy (median dose of 7020 cGy) from February 1988 to March 1996 at St. Mary's Hospital. Overexpression of p53 was correlated with locoregional control and survival using Kaplan-Meier method. A Cox regression multivariate analysis was performed that included all clinical variables and status of p53 expression. Thirty-seven (67.2%) patients showed overexpression of p53 by immunohistochemical staining in their tumor. One hundred percent of oral cavity, 76% of laryngeal, 66.7% of oropharyngeal, 66.7% of hypopharyngeal cancer showed p53 overexpression (p=0.05). The status of p53 had significant relationship with stage of disease (p=0.03) and history of smoking (p=0.001). The overexpression of p53 was not predictive of response rate to radiation therapy. The locoregional control was not significantly affected by p53 status. Overexpression of p53 didn't have any prognostic implication for disease free survival and overall survival. Primary site and stage of disease were significant prognostic factors for survival. The p53 overexpression as detected by immunohistochemical staining had significant correlation with stage, primary site of disease and smoking habit of patients. The p53 overexpression didn't have any predictive value for outcome of curative radiation therapy in a group of head and neck cancers

  11. P53 overexpression and outcome of radiation therapy in head and neck cancers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Ah; Choi, Ihl Bhong; Kang, Ki Mun; Jang, Ji Young; Kim, Kyung Mi; Park, Kyung Shin; Kim, Young Shin; Kang, Chang Suk; Cho, Seung Ho; Kim, Hyung Tae [College of Medicine, The Catholic Univ., Seoul (Korea, Republic of)

    1999-03-01

    Experimental studies have implicated the wild type p53 in cellular response to radiation. Whether altered p53 function can lead to changes in clinical radiocurability remains an area of ongoing study. This study was performed to investigate whether any correlation between change of p53 and outcome of curative radiation therapy in patients with head and neck cancers. Immunohistochemical analysis with a mouse monoclonal antibody (D0-7) specific for human p53 was used to detect to overexpression of protein in formalin fixed, paraffin-embedded tumor sample from 55 head and neck cancer patients treated with curative radiation therapy (median dose of 7020 cGy) from February 1988 to March 1996 at St. Mary's Hospital. Overexpression of p53 was correlated with locoregional control and survival using Kaplan-Meier method. A Cox regression multivariate analysis was performed that included all clinical variables and status of p53 expression. Thirty-seven (67.2%) patients showed overexpression of p53 by immunohistochemical staining in their tumor. One hundred percent of oral cavity, 76% of laryngeal, 66.7% of oropharyngeal, 66.7% of hypopharyngeal cancer showed p53 overexpression (p=0.05). The status of p53 had significant relationship with stage of disease (p=0.03) and history of smoking (p=0.001). The overexpression of p53 was not predictive of response rate to radiation therapy. The locoregional control was not significantly affected by p53 status. Overexpression of p53 didn't have any prognostic implication for disease free survival and overall survival. Primary site and stage of disease were significant prognostic factors for survival. The p53 overexpression as detected by immunohistochemical staining had significant correlation with stage, primary site of disease and smoking habit of patients. The p53 overexpression didn't have any predictive value for outcome of curative radiation therapy in a group of head and neck cancers.

  12. P53-miR-191-SOX4 regulatory loop affects apoptosis in breast cancer.

    Science.gov (United States)

    Sharma, Shivani; Nagpal, Neha; Ghosh, Prahlad C; Kulshreshtha, Ritu

    2017-08-01

    miRNAs have emerged as key participants of p53 signaling pathways because they regulate or are regulated by p53. Here, we provide the first study demonstrating direct regulation of an oncogenic miRNA, miR-191-5p, by p53 and existence of a regulatory feedback loop. Using a combination of qRT-PCR, promoter-luciferase, and chromatin-immunoprecipitation assays, we show that p53 brings about down-regulation of miR-191-5p in breast cancer. miR-191-5p overexpression brought about inhibition of apoptosis in breast cancer cell lines (MCF7 and ZR-75) as demonstrated by reduction in annexin-V stained cells and caspase 3/7 activity, whereas miR-191-5p down-regulation showed the opposite. We further unveiled that SOX4 was a direct target of miR-191-5p. SOX4 overexpression was shown to increase p53 protein levels in MCF7 cells. miR-191-5p overexpression brought about down-regulation of SOX4 and thus p53 levels, suggesting the existence of a regulatory feedback loop. Breast cancer treatment by doxorubicin, an anti-cancer drug, involves induction of apoptosis by p53; we thus wanted to check whether miR-191-5p affects doxorubicin sensitivity. Interestingly, Anti-miR-191 treatment significantly decreased the IC50 of the doxorubicin drug and thus sensitized breast cancer cells to doxorubicin treatment by promoting apoptosis. Overall, this work highlights the importance of the p53-miR-191- SOX4 axis in the regulation of apoptosis and drug resistance in breast cancer and offers a preclinical proof-of-concept for use of an Anti-miR-191 and doxorubicin combination as a rational approach to pursue for better breast cancer treatment. © 2017 Sharma et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  13. Overexpression of p53, MDM2 proteins in some atr radiation-induced skin ulcers

    International Nuclear Information System (INIS)

    Gu Qingyang; Gao Yabing; Wang Dewen; Cui Yufang; Zhao Po; Yang Zhixiang; Zhou Jie

    2000-01-01

    An animal model of radiation-induced skin ulcer was set up with 140 rats, which were locally irradiated with 35-55 Gy γ-rays. The pathological changes were observed for 1 year. Immunohistochemical studies were performed in 72 rat radiation skin ulcer specimens using anti-p53 and anti-MDM2 proteins polyclonal antibodies. The results showed that the positive rate for overexpression of p53 protein was 9.7%, and for that of MDM2 was 19.4%. The overexpression of p53 was mainly seen in the nuclei of activated squamous epithelial cells, and in fibroblasts, endotheliocytes in deeper part of the skin ulcers. The overexpression of MDM2 had the same localizations. It is suggested that the changes of p53 and MDM2, genes and proteins, may be related to the cancer transformation and poor healing of radiation-induced skin ulcers

  14. p53 Over-expression and p53 mutations in colon carcinomas: Relation to dietary risk factors

    NARCIS (Netherlands)

    Voskuil, D.W.; Kampman, E.; Kraats, A.A. van; Balder, H.F.; Muijen, G.N.P. van; Goldbohm, R.A.; Veer, P. van 't

    1999-01-01

    Epidemiological studies have suggested that dietary factors may differently affect p53-dependent and p53-independent pathways to colon cancer. Results of such studies may depend on the method used to assess p53 status. This case-control study of 185 colon-cancer cases and 259 controls examines this

  15. P53 autoantibodies in 1006 patients followed up for breast cancer

    International Nuclear Information System (INIS)

    Metcalfe, Su; Wheeler, Terence K; Picken, Sheila; Negus, Susanne; Jo Milner, A

    2000-01-01

    to p53 would reflect tumour behaviour. However, we found that the presence or absence of p53 autoantibodies was not predictive of presence or absence of recurrent disease. There was an equivalent incidence of active disease at the time of sampling in both the autoantibody-negative and autoantibody-positive groups, these being 25.2 and 28.7%, respectively. Thus, humoral immune activity against p53 appeared to be relatively restricted to a subgroup of patients in whom, once an autoantibody response had been generated, antibody was likely to persist regardless of tumour behaviour. Conversely, where no detectable p53 autoantibody was present at the time of primary diagnosis, these patients remained similarly negative for antibody, irrespective of subsequent disease activity (Table 3). In contrast to shed markers that correlate with tumour mass, such as CA15.3 for cancer of the breast, any tumour-related immune response will be subject to complex regulation. Autoantibody responses to p53 will require appropriate primary immunization; initial low-dose antigen exposure may induce immune tolerance and lack of response. Higher antigen doses may activate either antibody-mediated immunity, or cellular immunity. In breast cancer patients, our results suggest that, once an active humoral response against p53 is established, then this remains active. This persistent humoral reaction may be driven by persistent antigenic stimulation by p53 protein derived from overexpression of p53 at distant metastatic sites; alternatively, irradiated normal tissue may be a source of continued antigenic stimulation, because a long-term side effect of radiation therapy is an increased expression of p53 in normal breast tissue that persists for several years [12]. Since the great majority of our total patient cohort had received radiotherapy, humoral immunity to p53 associated with primary disease might persist, even in those patients who enter remission, due to tumour-independent antigenic

  16. Tumor suppressor p53 biology, its role in radioresponse and the analysis of p53 mutation/expression among Filipino breast cancers

    International Nuclear Information System (INIS)

    Deocaris, Custer C.

    2004-01-01

    Ionizing radiation remains one of the most effective tools for the treatment of breast cancer. It combines properties of a potent DNA-damaging agent and high degree of spatial specificity to the target tissue. Nonetheless, there remain considerable differences in the outcome for treatment of tumors of differing histological type treated by radiotherapy. The identification of predictive indicators of radiosensitivity is crucial for selecting patients suited for preoperative radiotherapy as well as those unwarranted for postoperative treatments. To improve prognostication, numerous genes involved in the breast carcinogenesis have been studied and thus far over the last decade several multi-center researches converge on the role of tumor suppressor p53 in tumor biology. The p53 gene is located on the short arm of chromosome 17 and encodes a 53-kd nuclear protein, p-53, also referred to as 'the guardian of the genome', it orchestrates multiple cellular processes such as cell growth control, DNA repair and programmed cell death. During radiotherapy, genotoxic damage induces p53 overexpression in order to control the rate of proliferating damaged cells, repair damage or induce the apoptotic pathway. Its molecular inactivation in a tumor cell, typically by a point mutation, leads to chemo/radio resistance due to the inability of the molecule to trigger p53-dependent programmed cell death

  17. 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.

  18. P53 overexpression in head and neck carcinoma and radiotherapy results

    International Nuclear Information System (INIS)

    Awwad, Saif; Jaros, Evelyn; Somes, James; Lunec, John

    1996-01-01

    Purpose: P53 gene mutations are the common genetic changes encountered in human cancers, and there is extensive evidence that the P53 status may determine tumor response to therapy. This study was carried out to investigate whether there is any correlation between accumulation (overexpression) of P53 protein and poor prognosis in patients with head and neck carcinomas treated with radical radiotherapy. Methods and Materials: Seventy-nine patients with head and neck carcinomas who were diagnosed and treated in 1989-90 with curative radiotherapy were studied retrospectively. Paraffin sections from archival material were studied using immunohistochemical staining (IHC) with mouse monoclonal antibodies (D0-7) to human P53 protein. Univariate and multivariate analysis of loco-regional tumor control and patient survival were performed on possible prognostic factors. Results: Forty-two (53%) patients showed positive IHC staining in their tumors. Fifty-three percent of the laryngeal, 64% of the oropharyngeal, and 43% of the oral cavity carcinomas showed P53 overexpression. All tumor specimens with vascular, lymphatic, and/or sarcolemmal invasion showed P53 overexpression. The proportion of tumor-stained nuclei was higher in the poorly differentiated than in the well and moderately differentiated tumors (p < 0.05), but there was no correlation with the patient overall or disease-free 5-year actuarial survival. There was no difference in the 5-year actuarial survival and disease-free survival between patients with P53 immunostaining in their tumors and those with no immunostaining (59% vs. 65% and 57% vs. 51%, respectively). The TNM tumor stage was the most significant prognostic factor with 5-year actuarial survival of 87% for early and 14% for late stages (p << 0.0001). There was a significant correlation between immunostaining and history of smoking (p = 0.02). Conclusion: The data demonstrate that the P53 accumulation as detected by immunohistochemical staining in a

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

    International Nuclear Information System (INIS)

    Tong, Qiang-Song; Zheng, Li-Duan; Wang, Liang; Liu, Jun; Qian, Wei

    2004-01-01

    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. 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. BAK gene transfer could result in significant BAK overexpression, decreased in vitro growth, cell cycle G 0 /G 1 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. 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

  1. Functional Significance of Mutant p53 in Breast Cancer

    National Research Council Canada - National Science Library

    O'Lear, Renee

    2001-01-01

    ... in those cells with irreparable damage. In human tumors, many hot-spot mutations are found within the DNA-binding domain of p53, rendering it incapable of sequence-specific transactivation of target genes such as p21, bax, and mdm2...

  2. Functional Significance of Mutant p53 in Breast Cancer

    National Research Council Canada - National Science Library

    O'Lear, Rene

    2002-01-01

    ... in those cells with irreparable damage. In human tumors, many hot-spot mutations are found within the DNA-binding domain of p53, rendering it incapable of sequence-specific transactivation of target genes such as p2l, bax, and mdm2...

  3. Pure versus combined Merkel cell carcinomas: immunohistochemical evaluation of cellular proteins (p53, Bcl-2, and c-kit) reveals significant overexpression of p53 in combined tumors.

    Science.gov (United States)

    Lai, Jonathan H; Fleming, Kirsten E; Ly, Thai Yen; Pasternak, Sylvia; Godlewski, Marek; Doucette, Steve; Walsh, Noreen M

    2015-09-01

    Merkel cell polyomavirus is of oncogenic significance in approximately 80% of Merkel cell carcinomas. Morphological subcategories of the tumor differ in regard to viral status, the rare combined type being uniformly virus negative and the predominant pure type being mainly virus positive. Indications that different biological subsets of the tumor exist led us to explore this diversity. In an Eastern Canadian cohort of cases (75 patients; mean age, 76 years [range, 43-91]; male/female ratio, 43:32; 51 [68%] pure and 24 [34%] combined tumors), we semiquantitatively compared the immunohistochemical expression of 3 cellular proteins (p53, Bcl-2, and c-kit) in pure versus combined groups. Viral status was known in a subset of cases. The significant overexpression of p53 in the combined group (mean [SD], 153.8 [117.8] versus 121.6 [77.9]; P = .01) and the increased epidermal expression of this protein (p53 patches) in the same group lend credence to a primary etiologic role for sun damage in these cases. Expression of Bcl-2 and c-kit did not differ significantly between the 2 morphological groups. A relative increase in c-kit expression was significantly associated with a virus-negative status (median [interquartile range], 100 [60-115] versus 70 [0-100]; P = .03). Emerging data reveal divergent biological pathways in Merkel cell carcinoma, each with a characteristic immunohistochemical profile. Virus-positive tumors (all pure) exhibit high retinoblastoma protein and low p53 expression, whereas virus-negative cases (few pure and all combined) show high p53 and relatively high c-kit expression. The potential biological implications of this dichotomy call for consistent stratification of these tumors in future studies. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Troester, Melissa A; Herschkowitz, Jason I; Oh, Daniel S; He, Xiaping; Hoadley, Katherine A; Barbier, Claire S; Perou, Charles M

    2006-01-01

    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). 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. 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. 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 lists. Our biologically-based refinements excluded genes

  5. Downregulated long non-coding RNA MEG3 in breast cancer regulates proliferation, migration and invasion by depending on p53’s transcriptional activity

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Lin [West Biostatistics and Cost-effectiveness Research Center, Medical Insurance Office, West China Hospital of Sichuan University, 610041, Sichuan (China); Li, Yu [Department of Anesthesiology, West China Hospital, Sichuan University, 610041, Sichuan (China); Yang, Bangxiang, E-mail: b19933009@qq.coom [Department of Pain Management, West China Hospital of Sichuan University, 610041, Sichuan (China)

    2016-09-09

    Long non-coding RNAs (lncRNAs) was found to play critical roles in tumorigenesis, hence, screen of tumor-related lncRNAs, identification of their biological roles is important for understanding the processes of tumorigenesis. In this study, we identified the expressing difference of several tumor-related lncRNAs in breast cancer samples and found that, MEG3, which is downregulated in non-small cell lung cancer (NSCLC) tumor tissues, is also downregulated in breast cancer samples compared with adjacent tissues. For figuring out the effect of MEG3 in breast cancer cells MCF7 and MB231, we overexpressed MEG3 in these cells, and found that it resulted the inhibition of proliferation, colony formation, migration and invasion capacities by enhancing p53’s transcriptional activity on its target genes, including p21, Maspin and KAI1. MEG3 presented similar effects in MB157, which is a p53-null breast cancer cell line, when functional p53 but not p53R273H mutant, which lacks transcriptional activity, was introduced. Surprisingly, overexpression of MEG3 activates p53’s transcriptional activity by decreasing MDM2’s transcription level, and thus stabilizes and accumulates P53. Taken together, our findings indicate that MEG3 is downregulated in breast cancer tissues and affects breast cancer cells’ malignant behaviors, which indicate MEG3 a potential therapeutic target for breast cancer. - Highlights: • MEG3 RNA is widely downregulated in breast tumor tissue. • MEG3 regulates P53 indirectly through transcriptional regulation of MDM2. • Under unstressed condition, MEG3-related P53 accumulation transcriptionally activates p53’s target genes. • MEG3 expression level tightly regulates proliferation, colony formation, migration and invasion in breast tumor cells.

  6. 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.

  7. 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.

  8. Overexpression of p53 activated by small activating RNA suppresses the growth of human prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Ge Q

    2016-01-01

    Full Text Available Qiangqiang Ge,1,* Chenghe Wang,2,* Yajun Ruan,1,* Zhong Chen,1 Jihong Liu,1 Zhangqun Ye1 1Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 2Department of Urology, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Previous research has reported that a particular double-stranded RNA, named dsP53-285, has the capacity to induce expression of the tumor suppressor gene TP53 in chimpanzee cells by targeting its promoter. Usually, it is the wild-type p53 protein, rather than mutants, which exhibits potent cancer-inhibiting effects. In addition, nonhuman primates, such as chimpanzees, share almost identical genome sequences with humans. This prompted us to speculate whether dsP53-285 can trigger wild-type p53 protein expression in human prostate cancer (PCa cells and consequently suppress cell growth. The human PCa cell lines LNCaP and DU145 were transfected with dsP53-285 for 72 hours. Compared with the dsControl and mock transfection groups, expression of both p53 messenger RNA and p53 protein was significantly enhanced after dsP53-285 transfection, and this enhancement was followed by upregulation of p21, which indirectly indicated that dsP53-285 induced wild-type p53 expression. Moreover, overexpression of wild-type p53 mediated by dsP53-285 downregulated the expression of Cyclin D1 and cyclin-dependent kinase 4/6, thereby inducing PCa cell cycle arrest in G0/G1 phase and then inhibiting cell proliferation and clonogenicity. More importantly, dsP53-285 suppressed PCa cells mainly by modulating wild-type p53 expression. In conclusion, our study provides evidence that dsP53-285 can significantly stimulate wild-type p53 expression in the human PCa cell lines LNCaP and DU145 and can exert potent antitumor effects. Keywords: p53, small activating RNA, prostate

  9. Prognosis for Survival of Young Women with Breast Cancer by Quantitative p53 Immunohistochemistry

    Science.gov (United States)

    Axelrod, David E.; Shah, Kinsuk; Yang, Qifeng; Haffty, Bruce G.

    2015-01-01

    p53 protein detected immunohistochemically has not been accepted as a biomarker for breast cancer patients because of disparate reports of the relationship between the amount of p53 protein detected and patient survival. The purpose of this study was to determine experimental conditions and methods of data analysis for which p53 stain intensity could be prognostic for survival of young breast cancer patients. A tissue microarray of specimens from 93 patients was stained with anti-p53 antibody, and stain intensity measured with a computer-aided image analysis system. A cut-point at one standard deviation below the mean of the distribution of p53 stain intensity separated patients into two groups with significantly different survival. These results were confirmed by Quantitative Nuclear Grade determined by DNA-specific Feulgen staining. P53 provided information beyond ER and PR status. Therefore, under the conditions reported here, p53 protein can be an effective prognostic factor for young breast cancer patients. PMID:26322145

  10. Overexpression of 15-lipoxygenase-1 induces growth arrest through phosphorylation of p53 in human colorectal cancer cells.

    Science.gov (United States)

    Kim, Jong-Sik; Baek, Seung Joon; Bottone, Frank G; Sali, Tina; Eling, Thomas E

    2005-09-01

    To investigate the function of 15-lipoxygenase-1 (15-LOX-1) in human colorectal cancer, we overexpressed 15-LOX-1 in HCT-116 human colorectal cancer cells. Clones expressing the highest levels of 15-LOX-1 displayed reduced viability compared with the HCT-116-Vector control cells. Further, by cell cycle gene array analyses, the cyclin-dependent kinase inhibitor p21WAF1/CIP1 and MDM2 genes were up-regulated in 15-LOX-1-overexpressing cells. The induction of p21(WAF1/CIP1) and MDM2 were linked to activation of p53 by 15-LOX-1, as there was a dramatic induction of phosphorylated p53 (Ser15) in 15-LOX-1-overesxpressing cells. However, the 15-LOX-1 metabolites 13(S)-hydroxyoctadecadienoic acid and 15(S)-hydroxyeicosatetraenoic acid failed to induce phosphorylation of p53 at Ser15, and the 15-LOX-1 inhibitor PD146176 did not inhibit the phosphorylation of p53 at Ser15 in 15-LOX-1-overexpressing cells. Nonetheless, the growth-inhibitory effects of 15-LOX-1 were p53 dependent, as 15-LOX-1 overexpression had no effect on cell growth in p53 (-/-) HCT-116 cells. Finally, treatment of HCT-116-15-LOX-1 cells with different kinase inhibitors suggested that the effects of 15-LOX-1 on p53 phosphorylation and activation were due to effects on DNA-dependent protein kinase. Collectively, these findings suggest a new mechanism to explain the biological activity of 15-LOX-1, where 15-LOX plays a stoichiometric role in activating a DNA-dependent protein kinase-dependent pathway that leads to p53-dependent growth arrest.

  11. Vaccination with p53-peptide-pulsed dendritic cells, of patients with advanced breast cancer: report from a phase I study

    DEFF Research Database (Denmark)

    Svane, Inge Marie; Pedersen, Anders E; Johnsen, Hans E

    2004-01-01

    the treatment. In conclusion, the strategy for p53-DC vaccination seems safe and without toxicity. Furthermore, indications of both immunologic and clinical effect were found in heavily pretreated patients with advanced breast cancer. An independent clinical effect of repeated administration of DCs and IL-2 can......Peptides derived from over-expressed p53 protein are presented by class I MHC molecules and may act as tumour-associated epitopes. Due to the diversity of p53 mutations, immunogenic peptides representing wild-type sequences are preferable as a basis for a broad-spectrum p53-targeting cancer vaccine......) loaded with a cocktail of three wild-type and three modified p53 peptides are being analysed in six HLA-A2+ patients with progressive advanced breast cancer. Vaccinations were well tolerated and no toxicity was observed. Disease stabilisation was seen in two of six patients, one patient had a transient...

  12. Immunohistochemical study of p53 overexpression in radiation-induced colon cancers

    International Nuclear Information System (INIS)

    Minami, Kazunori; Hayashi, Nobuyuki; Mokarim, A.; Matsuzaki, Sumihiro; Ito, Masahiro; Sekine, Ichiro.

    1998-01-01

    The expressions of p53 and proliferating cell nuclear antigen (PCNA) were studied immunohistochemically from paraffin sections of 7 cases (9 lesions) of radiation-induced colon cancer and 42 cases of spontaneous colon cancer. Age distribution of radiation-induced and spontaneous colon cancer were 68.1 years (range, 56 to 77 years) and 67.4 years (range, 31 to 85 years), respectively. Among the radiation-induced colon cancers, there were 3 lesions of mucinous carcinoma (33%), a much higher than found for spontaneous mucinous cancer. Immunohistochemically, p53 protein expression was detected in 7/9 (78%) of radiation-induced cancers and in 23/42 (55%) of spontaneous colon cancers. χ 2 analysis found no significant differences between radiation-induced and spontaneous colon cancers in age distribution or p53-positive staining for frequency, histopathology, or Dukes'' classification. In radiation colitis around the cancers including aberrant crypts, spotted p53 staining and abnormal and scattered PCNA-positive staining were observed. In histologically normal cells, p53 staining was almost absent and PCNA-positive staining was regularly observed in the lower half of the crypt. In radiation colitis including aberrant glands, cellular proliferation increased and spotted p53 expression was observed. This study suggests that radiation colitis and aberrant glands might possess malignant potential and deeply associate with carcinogenesis of radiation-induced colon cancer. (author)

  13. A combination of p53-activating APR-246 and phosphatidylserine-targeting antibody potently inhibits tumor development in hormone-dependent mutant p53-expressing breast cancer xenografts

    Directory of Open Access Journals (Sweden)

    Liang Y

    2018-03-01

    Full Text Available Yayun Liang,1 Benford Mafuvadze,1 Cynthia Besch-Williford,2 Salman M Hyder1 1Deparment of Biomedical Sciences and Dalton Cardiovascular Research Center, Columbia, MO, USA; 2IDEXX BioResearch, Columbia, MO, USA Background: Between 30 and 40% of human breast cancers express a defective tumor suppressor p53 gene. Wild-type p53 tumor suppressor protein promotes cell-cycle arrest and apoptosis and inhibits vascular endothelial growth factor–dependent angiogenesis, whereas mutant p53 protein (mtp53 lacks these functions, resulting in tumor cell survival and metastasis. Restoration of p53 function is therefore a promising drug-targeted strategy for combating mtp53-expressing breast cancer. Methods: In this study, we sought to determine whether administration of APR-246, a small-molecule drug that restores p53 function, in combination with 2aG4, an antibody that targets phosphatidylserine residues on tumor blood vessels and disrupts tumor vasculature, effectively inhibits advanced hormone-dependent breast cancer tumor growth. Results: APR-246 reduced cell viability in mtp53-expressing BT-474 and T47-D human breast cancer cells in vitro, and significantly induced apoptosis in a dose-dependent manner. However, APR-246 did not reduce cell viability in MCF-7 breast cancer cells, which express wild-type p53. We next examined APR-246’s anti-tumor effects in vivo using BT-474 and T47-D tumor xenografts established in female nude mice. Tumor-bearing mice were treated with APR-246 and/or 2aG4 and tumor volume followed over time. Tumor growth was more effectively suppressed by combination treatment than by either agent alone, and combination therapy completely eradicated some tumors. Immunohistochemistry analysis of tumor tissue sections demonstrated that combination therapy more effectively induced apoptosis and reduced cell proliferation in tumor xenografts than either agent alone. Importantly, combination therapy dramatically reduced the density of blood

  14. 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.

  15. p53 Loss Synergizes with Estrogen and Papillomaviral Oncogenes to Induce Cervical and Breast Cancers

    Science.gov (United States)

    Shai, Anny; Pitot, Henry C.; Lambert, Paul F.

    2010-01-01

    Whereas the tumor suppressor p53 gene is frequently mutated in most human cancers, this is not the case in human papillomavirus (HPV)-associated cancers, presumably because the viral E6 oncoprotein inactivates the p53 protein. The ability of E6 to transform cells in tissue culture and induce cancers in mice correlates in part with its ability to inactivate p53. In this study, we compared the expression of the HPV16 E6 oncogene to the conditional genetic disruption of p53 in the context of a mouse model for cervical cancer in which estrogen is a critical cofactor. Nearly all of the K14Crep53f/f mice treated with estrogen developed cervical cancer, a stark contrast to its complete absence in like-treated K14E6WTp53f/f mice, indicating that HPV16 E6 must only partially inactivate p53. p53-independent activities of E6 also contributed to carcinogenesis, but in the female reproductive tract, these activities were manifested only in the presence of the HPV16 E7 oncogene. Interestingly, treatment of K14Crep53f/f mice with estrogen also resulted in mammary tumors after only a short latency, many of which were positive for estrogen receptor α. The majority of these mammary tumors were of mixed cell types, suggestive of their originating from a multipotent progenitor. Furthermore, a subset of mammary tumors arising in the estrogen-treated, p53-deficient mammary glands exhibited evidence of an epithelial to mesenchymal transition. These data show the importance of the synergy between estrogen and p53 insufficiency in determining basic properties of carcinogenesis in hormone-responsive tissues, such as the breast and the reproductive tract. PMID:18413729

  16. Evaluation of HER2 and p53 expression in predicting response to docetaxel-based first-line chemotherapy in advanced breast cancer

    Directory of Open Access Journals (Sweden)

    Martini Leonardo

    2011-04-01

    Full Text Available Abstract Background The human epidermal growth factor receptor 2 (HER2 and p53 pathways may be involved in chemotherapy sensitivity and/or resistance. We explore the value of HER2 and p53 status to foretell docetaxel sensitivity in advanced breast cancer. Methods HER2 and p53 expression was analysed in 36 (median age 55 yrs; range 37-87 metastatic breast cancer patients receiving docetaxel-based first-line chemotherapy. HER2 was determined by immunohistochemistry (IHC and fluorescence in situ hybridization (FISH, p53 was tested by IHC. We correlate the expression of study parameters with pathologic parameters, RECIST response and survival. The standard cut-off value of 2 was used to determine HER2 overexpression while p53 mean expression level was used to divide low/high expressors tumors. Results Median time to progression and overall survival were 9 (range 2 - 54 and 20 (range 3 - 101 months. Overall response rate was 41.6%. Nine cases showed HER2 overexpression. HER2 was more frequently overexpressed in less differentiated (p = 0.05 and higher stage (p = 0.003 disease. Mean FISH-HER2 values were significantly higher in responder than in non-responder pts (8.53 ± 10.21 vs 2.50 ± 4.12, p = 0.027. Moreover, HER2 overexpression correlates with treatment response at cross-tabulation analysis (p = 0.046. p53 expression was only associated with higher stage disease (p = 0.02 but lack of any significant association with HER status or docetaxel response. No significant relation with survival was observed for any parameter. Conclusion Our data seem to indicate that FISH-determined HER2 status but not p53 is associated with docetaxel sensitivity in metastatic breast cancer.

  17. Cdk5 phosphorylates non-genotoxically overexpressed p53 following inhibition of PP2A to induce cell cycle arrest/apoptosis and inhibits tumor progression

    Directory of Open Access Journals (Sweden)

    Kumari Ratna

    2010-07-01

    Full Text Available Abstract Background p53 is the most studied tumor suppressor and its overexpression may or may not cause cell death depending upon the genetic background of the cells. p53 is degraded by human papillomavirus (HPV E6 protein in cervical carcinoma. Several stress activated kinases are known to phosphorylate p53 and, among them cyclin dependent kinase 5 (Cdk5 is one of the kinase studied in neuronal cell system. Recently, the involvement of Cdk5 in phosphorylating p53 has been shown in certain cancer types. Phosphorylation at specific serine residues in p53 is essential for it to cause cell growth inhibition. Activation of p53 under non stress conditions is poorly understood. Therefore, the activation of p53 and detection of upstream kinases that phosphorylate non-genotoxically overexpressed p53 will be of therapeutic importance for cancer treatment. Results To determine the non-genotoxic effect of p53; Tet-On system was utilized and p53 inducible HPV-positive HeLa cells were developed. p53 overexpression in HPV-positive cells did not induce cell cycle arrest or apoptosis. However, we demonstrate that overexpressed p53 can be activated to upregulate p21 and Bax which causes G2 arrest and apoptosis, by inhibiting protein phosphatase 2A. Additionally, we report that the upstream kinase cyclin dependent kinase 5 interacts with p53 to phosphorylate it at Serine20 and Serine46 residues thereby promoting its recruitment on p21 and bax promoters. Upregulation and translocation of Bax causes apoptosis through intrinsic mitochondrial pathway. Interestingly, overexpressed activated p53 specifically inhibits cell-growth and causes regression in vivo tumor growth as well. Conclusion Present study details the mechanism of activation of p53 and puts forth the possibility of p53 gene therapy to work in HPV positive cervical carcinoma.

  18. Knockout and transgenic mice of Trp53: what have we learned about p53 in breast cancer?

    International Nuclear Information System (INIS)

    Blackburn, Anneke C; Jerry, D Joseph

    2002-01-01

    The human p53 tumor suppressor gene TP53 is mutated at a high frequency in sporadic breast cancer, and Li-Fraumeni syndrome patients who carry germline mutations in one TP53 allele have a high incidence of breast cancer. In the 10 years since the first knockout of the mouse p53 tumor suppressor gene (designated Trp53) was published, much has been learned about the contribution of p53 to biology and tumor suppression in the breast through the use of p53 transgenic and knockout mice. The original mice deficient in p53 showed no mammary gland phenotype. However, studies using BALB/c-Trp53-deficient mice have demonstrated a delayed involution phenotype and a mammary tumor phenotype. Together with other studies of mutant p53 transgenes and p53 bitransgenics, a greater understanding has been gained of the role of p53 in involution, of the regulation of p53 activity by hormones, of the effect of mouse strain and modifier genes on tumor phenotype, and of the cooperation between p53 and other oncogenic pathways, chemical carcinogens and hormonal stimulation in mammary tumorigenesis. Both p53 transgenic and knockout mice are important in vivo tools for understanding breast cancer, and are yet to be exploited for developing therapeutic strategies in breast cancer

  19. Lunatic Fringe and p53 Cooperatively Suppress Mesenchymal Stem-Like Breast Cancer

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Chung

    2017-11-01

    Full Text Available Claudin-low breast cancer (CLBC is a poor prognosis molecular subtype showing stemness and mesenchymal features. We previously discovered that deletion of a Notch signaling modulator, Lunatic Fringe (Lfng, in the mouse mammary gland induced a subset of tumors resembling CLBC. Here we report that deletion of one copy of p53 on this background not only accelerated mammary tumor development but also led to a complete penetrance of the mesenchymal stem-like phenotype. All mammary tumors examined in the Lfng/p53 compound mutant mice displayed a mesenchymal/spindloid pathology. These tumors showed high level expressions of epithelial-to-mesenchymal transition (EMT markers including Vimentin, Twist, and PDGFRα, a gene known to be enriched in CLBC. Prior to tumor onset, Lfng/p53 mutant mammary glands exhibited increased levels of Vimentin and E-cadherin, but decreased expressions of cytokeratin 14 and cytokeratin 8, accompanied by elevated basal cell proliferation and an expanded mammary stem cell-enriched population. Lfng/p53 mutant glands displayed increased accumulation of Notch3 intracellular fragment, up-regulation of Hes5 and down-regulation of Hes1. Analysis in human breast cancer datasets found the lowest HES1 and second lowest LFNG expressions in CLBC among molecular subtypes, and low level of LFNG is associated with poor survival. Immunostaining of human breast cancer tissue array found correlation between survival and LFNG immunoreactivity. Finally, patients carrying TP53 mutations express lower LFNG than patients with wild type TP53. Taken together, these data revealed genetic interaction between Lfng and p53 in mammary tumorigenesis, established a new mouse model resembling CLBC, and may suggest targeting strategy for this disease.

  20. Profiling of oligosaccharides and p53 gene mutation in Filipino breast tumors

    International Nuclear Information System (INIS)

    Deocaris, Custer C.; De Vera, Azucena C.; Magno, Jose Donato A.; Cruz, Michael Joseph B.; Prodigalidad, Abelardo-Alan T.; Jacinto, Sonia D.

    2010-01-01

    Majority of patients are diagnosed with benign tumors, however, such benign tumors can progress to an invasive disease. Since carbohydrate-mediated cell-cell adhesion and proliferative potential play crucial roles in tumorigenesis and tumor aggressive behavior, we analyzed the qualitative changes in oligosaccharide expression and analyzed for presence of mutation in the tumor suppressor p53 gene, the most mutated gene in all human cancers. Forty-three (43) breast tumors were screened for p53 mutation in exons 2-11 using polymerase chain reaction (PCR)-amplification coupled to temporal temperature gradient electrophoresis (TTGE). Paraffin-embedded tissues were stained with biotinylated-glycoproteins containing the following sugar groups: mannose (Man), lactose (Lac), fucoidan (Fuc), N-acetyl-glucosamine (GlcNac), N-acetyl-b-galactosamine (GalNAc) and hyaluronic acid (Hya). Expression of carbohydrate receptors was significantly elevated (p=0.003) in malignant compared with benign tumors, particularly at receptors for GalNAc, lac and Fuc. No change in overall glycan signatures using our panel of neoglycoconjugates was noted when grouped according to p53 mutation status in both benign and malignant cases. Although the prognostic value of carbohydrate-receptors in breast cancer has not been validated to date, our results indicate that benign and malignant tumors can be defined by their affinities to our battery of neoglyconjugates. However, result from our reverse lectin histochemistry failed to correlated glycan signature with presence of p53 mutations. (author)

  1. Concurrent overexpression of serum p53 mutation related with Helicobacter pylori infection

    Directory of Open Access Journals (Sweden)

    Lorenzo-Peñuelas Antonio

    2010-06-01

    Full Text Available Abstract Background & Aims In the province of Cadiz (Spain, the adjusted mortality rate for gastric cancer in the coastal town of Barbate is 10/100.000 inhabitants, whereas in the inland town of Ubrique, the rate is twice as high. The rate of Helicobacter pylori (H. pylori infection (H. pylori antibodies in the normal population was 54% in Ubrique, but only 32% in Barbate. In the two decades since its original discovery, p53 has found a singularly prominent place in our understanding of human gastric cancer and H. pylori cause accumulation of reactive oxygen species in the mucosa compartment. This study was designed to compare serum levels of p53 in a population characterized by high mortality due to stomach cancer and a high prevalence of H. pylori infection and another population in which mortality from this cause and the prevalence of H. pylori infection are low. Materials and methods 319 subjects from the low mortality population and 308 from the high mortality population were studied, as were 71 patients with stomach cancer. We measured serum immunoglobulin G antibody to H. pylori and serum mutant p53 protein and ceruloplasmin. Results The difference between the two populations in the prevalence of H. pylori infection was significant (p Conclusions There is a significant association between infection with H. pylori, elevated titers of H. pylori antibodies, and positivity for serum mutant p53 protein. Such information can significantly increase our basic knowledge in molecular pathology of gastric cancer and protection against H. pylori infection.

  2. Sirt1 overexpression suppresses fluoride-induced p53 acetylation to alleviate fluoride toxicity in ameloblasts responsible for enamel formation.

    Science.gov (United States)

    Suzuki, Maiko; Ikeda, Atsushi; Bartlett, John D

    2018-03-01

    Low-dose fluoride is an effective caries prophylactic, but high-dose fluoride is an environmental health hazard that causes skeletal and dental fluorosis. Treatments to prevent fluorosis and the molecular pathways responsive to fluoride exposure remain to be elucidated. Previously we showed that fluoride activates SIRT1 as an adaptive response to protect cells. Here, we demonstrate that fluoride induced p53 acetylation (Ac-p53) [Lys379], which is a SIRT1 deacetylation target, in ameloblast-derived LS8 cells in vitro and in enamel organ in vivo. Here we assessed SIRT1 function on fluoride-induced Ac-p53 formation using CRISPR/Cas9-mediated Sirt1 knockout (LS8 Sirt/KO ) cells or CRISPR/dCas9/SAM-mediated Sirt1 overexpressing (LS8 Sirt1/over ) cells. NaF (5 mM) induced Ac-p53 formation and increased cell cycle arrest via Cdkn1a/p21 expression in Wild-type (WT) cells. However, fluoride-induced Ac-p53 was suppressed by the SIRT1 activator resveratrol (50 µM). Without fluoride, Ac-p53 persisted in LS8 Sirt/KO cells, whereas it decreased in LS8 Sirt1/over . Fluoride-induced Ac-p53 formation was also suppressed in LS8 Sirt1/over cells. Compared to WT cells, fluoride-induced Cdkn1a/p21 expression was elevated in LS8 Sirt/KO and these cells were more susceptible to fluoride-induced growth inhibition. In contrast, LS8 Sirt1/over cells were significantly more resistant. In addition, fluoride-induced cytochrome-c release and caspase-3 activation were suppressed in LS8 Sirt1/over cells. Fluoride induced expression of the DNA double strand break marker γH2AX in WT cells and this was augmented in LS8 Sirt1/KO cells, but was attenuated in LS8 Sirt1/over cells. Our results suggest that SIRT1 deacetylates Ac-p53 to mitigate fluoride-induced cell growth inhibition, mitochondrial damage, DNA damage and apoptosis. This is the first report implicating Ac-p53 in fluoride toxicity.

  3. Mutant p53 protein in serum could be used as a molecular marker in human breast cancer.

    Science.gov (United States)

    Balogh, G A; Mailo, D A; Corte, M M; Roncoroni, P; Nardi, H; Vincent, E; Martinez, D; Cafasso, M E; Frizza, A; Ponce, G; Vincent, E; Barutta, E; Lizarraga, P; Lizarraga, G; Monti, C; Paolillo, E; Vincent, R; Quatroquio, R; Grimi, C; Maturi, H; Aimale, M; Spinsanti, C; Montero, H; Santiago, J; Shulman, L; Rivadulla, M; Machiavelli, M; Salum, G; Cuevas, M A; Picolini, J; Gentili, A; Gentili, R; Mordoh, J

    2006-04-01

    p53 wild-type is a tumor suppressor gene involved in DNA gene transcription or DNA repair mechanisms. When damage to DNA is unrepairable, p53 induces programmed cell death (apoptosis). The mutant p53 gene is the most frequent molecular alteration in human cancer, including breast cancer. Here, we analyzed the genetic alterations in p53 oncogene expression in 55 patients with breast cancer at different stages and in 8 normal women. We measured by ELISA assay the serum levels of p53 mutant protein and p53 antibodies. Immunohistochemistry and RT-PCR using specific p53 primers as well as mutation detection by DNA sequencing were also evaluated in breast tumor tissue. Serological p53 antibody analysis detected 0/8 (0%), 0/4 (0%) and 9/55 (16.36%) positive cases in normal women, in patients with benign breast disease and in breast carcinoma, respectively. We found positive p53 mutant in the sera of 0/8 (0.0%) normal women, 0/4 (0%) with benign breast disease and 29/55 (52.72%) with breast carcinoma. Immunohistochemistry evaluation was positive in 29/55 (52.73%) with mammary carcinoma and 0/4 (0%) with benign breast disease. A very good correlation between p53 mutant protein detected in serum and p53 accumulation by immunohistochemistry (83.3% positive in both assays) was found in this study. These data suggest that detection of mutated p53 could be a useful serological marker for diagnostic purposes.

  4. Proteomics Characterization of the Molecular Mechanisms of Mutant P53 Reactivation with PRIMA-1 in Breast Cancer Cells

    National Research Council Canada - National Science Library

    Daoud, Sayed S

    2006-01-01

    The main purpose of the study is to identify novel protein-protein interactions in various locations of cells to establish the molecular mechanisms of mutant p53 reactivation with PRIMA-1 in breast cancer cells...

  5. No evidence for functional inactivation of wild-type p53 protein by MDM2 overexpression in gastric carcinogenesis

    NARCIS (Netherlands)

    Blok, P.; Craanen, M. E.; Dekker, W.; Offerhaus, G. J.; Tytgat, G. N.

    1998-01-01

    Inactivation of wild-type p53 during gastric carcinogenesis is usually caused by mutations within exons 5-8 of the p53 gene leading to mutated, usually immunohistochemically detectable p53 proteins. However, functional inactivation of wild-type p53, mimicking mutational inactivation, may also result

  6. Significant difference in p53 and p21 protein immunoreactivity in HPV 16 positive and HPV negative breast carcinomas

    International Nuclear Information System (INIS)

    Hennig, E.M.; Norwegian Radium Hospital, Oslo; Kvinnsland, S.; Holm, R.; Nesland, J.M.

    1999-01-01

    Human papillomavirus (HPV) 16 has previously been found in 19/41 breast carcinomas (46%) in women with a history of HPV 16 positive CIN III lesions. There was no significant difference in distribution of histological subtypes, mean or median tumour diameter or number of regional lymph node metastases in the HPV positive and HPV negative breast carcinoma groups. P53, p21 and c-erbB-2 proteins were analyzed by immunohistochemistry in the HPV 16 positive and HPV negative breast carcinomas. There was a significant difference in p53 and p21 protein immunoreactivity between HPV 16 positive and HPV negative breast carcinomas (p=0.0091 and p=0.0040), with a significant less detectable p53 and p21 protein immunoreactivity in the HPV 16 positive cases. There was also a significant difference in the coexpression of p53/p21 between the HPV 16 positive and HPV 16 negative breast carcinomas (p=0.002). No significant difference in immunostaining for c-erbB-2 protein in the two groups was found (p=0.15), or for the coexpression of p53/c-erbB-2 (p=0.19). The significantly lower expression of p53 and p21 proteins in HPV 16 positive than in HPV 16 negative breast carcinomas supports the hypothesis of inactivation and degradation of wild-type p53 proteins by HPV 16 E6 and that p53 mutation is not necessary for transformation in the HPV 16 positive cases. (orig.)

  7. Exposure to depleted uranium does not alter the co-expression of HER-2/neu and p53 in breast cancer patients

    Directory of Open Access Journals (Sweden)

    Al-Toriahi Kaswer M

    2011-03-01

    Full Text Available Abstract Background Amongst the extensive literature on immunohistochemical profile of breast cancer, very little is found on populations exposed to a potential risk factor such as depleted uranium. This study looked at the immunohistochemical expression of HER-2/neu (c-erbB2 and p53 in different histological types of breast cancer found in the middle Euphrates region of Iraq, where the population has been exposed to high levels of depleted uranium. Findings The present investigation was performed over a period starting from September 2008 to April 2009. Formalin-fixed, paraffin-embedded blocks from 70 patients with breast cancer (62 ductal and 8 lobular carcinoma were included in this study. A group of 25 patients with fibroadenoma was included as a comparative group, and 20 samples of normal breast tissue sections were used as controls. Labeled streptavidin-biotin (LSAB+ complex method was employed for immunohistochemical detection of HER-2/neu and p53. The detection rate of HER-2/neu and p53 immunohistochemical expression were 47.14% and 35.71% respectively in malignant tumors; expression was negative in the comparative and control groups (p HER-2/neu immunostaining was significantly associated with histological type, tumor size, nodal involvement, and recurrence of breast carcinoma (p p Both biomarkers were positively correlated with each other. Furthermore, all the cases that co-expressed both HER-2/neu and p53 showed the most unfavorable biopathological profile. Conclusion P53 and HER-2/neu over-expression play an important role in pathogenesis of breast carcinoma. The findings indicate that in regions exposed to high levels of depleted uranium, although p53 and HER-2/neu overexpression are both high, correlation of their expression with age, grade, tumor size, recurrence and lymph node involvement is similar to studies that have been conducted on populations not exposed to depleted uranium. HER-2/neu expression in breast cancer was higher

  8. Progress of the correlation study between mammographic appearances and expression of p53, Ki-67 in patients with breast cancer

    International Nuclear Information System (INIS)

    Liu Jie; Liu Peifang

    2013-01-01

    Breast cancer is one of the most common female malignant tumors. The occurrence and development of breast cancer are often accompanied by abnormal gene expression. It has been well accepted that p53, Ki -67 are the commonly used biological indicators for clinical endocrine therapy and prognosis prediction. The oncogene expression reflects the malignant biological behavior of breast cancer from different perspectives. Those aggressive behaviors cause a variety of changes in histopathology and thus in imaging. Therefore, the imaging features of breast cancer may indirectly demonstrate the status of p53, Ki-67. Until now, because of its facility, low cost and high accuracy, mammography is still the preferred method in breast cancer screening and diagnosis. The relationship of mammographic appearances and gene expression in patients with breast cancer has potential clinical value in preoperative evaluation and planning of non-surgical treatment for those who are not able to perform immunohistochemistry. (authors)

  9. Low-level overexpression of p53 promotes warfarin-induced calcification of porcine aortic valve interstitial cells by activating Slug gene transcription.

    Science.gov (United States)

    Gao, Li; Ji, Yue; Lu, Yan; Qiu, Ming; Shen, Yejiao; Wang, Yaqing; Kong, Xiangqing; Shao, Yongfeng; Sheng, Yanhui; Sun, Wei

    2018-03-09

    The most frequently used oral anti-coagulant warfarin has been implicated in inducing calcification of aortic valve interstitial cells (AVICs), whereas the mechanism is not fully understood. The low-level activation of p53 is found to be involved in osteogenic transdifferentiation and calcification of AVICs. Whether p53 participates in warfarin-induced AVIC calcification remains unknown. In this study, we investigated the role of low-level p53 overexpression in warfarin-induced porcine AVIC (pAVIC) calcification. Immunostaining, quantitative PCR, and Western blotting revealed that p53 was expressed in human and pAVICs and that p53 expression was slightly increased in calcific human aortic valves compared with non-calcific valves. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling staining indicated that apoptosis slightly increased in calcific aortic valves than in non-calcific valves. Warfarin treatment led to a low-level increase of p53 mRNA and protein in both pAVICs and mouse aortic valves. Low-level overexpression of p53 in pAVICs via an adenovirus vector did not affect pAVIC apoptosis but promoted warfarin-induced calcium deposition and expression of osteogenic markers. shRNA-mediated p53 knockdown attenuated the pAVIC calcium deposition and osteogenic marker expression. Moreover, ChIP and luciferase assays showed that p53 was recruited to the slug promoter and activated slug expression in calcific pAVICs. Of note, overexpression of Slug increased osteogenic marker Runx2 expression, but not pAVIC calcium deposition, and Slug knockdown attenuated pAVIC calcification and p53-mediated pAVIC calcium deposition and expression of osteogenic markers. In conclusion, we found that p53 plays an important role in warfarin induced pAVIC calcification, and increased slug transcription by p53 is required for p53-mediated pAVIC calcification. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Data on the putative role of p53 in breast cancer cell adhesion: Technical information for adhesion assay

    Directory of Open Access Journals (Sweden)

    Kallirroi Voudouri

    2016-12-01

    Full Text Available In this data article, the potential role of p53 tumor suppressor gene (p53 on the attachment ability of MCF-7 breast cancer cells was investigated. In our main article, “IGF-I/ EGF and E2 signaling crosstalk through IGF-IR conduit point affect breast cancer cell adhesion” (K. Voudouri, D. Nikitovic, A. Berdiaki, D. Kletsas, N.K. Karamanos, G.N. Tzanakakis, 2016 [1], we describe the key role of IGF-IR in breast cancer cell adhesion onto fibronectin (FN. p53 tumor suppressor gene is a principal regulator of cancer cell proliferation. Various data have demonstrated an association between p53 and IGF-IR actions on cell growth through its’ putative regulation of IGF-IR expression. According to our performed experiments, p53 does not modify IGF-IR expression and does not affect basal MCF-7 cells adhesion onto FN. Moreover, technical details about the performance of adhesion assay onto the FN substrate were provided.

  11. Mutational myriad of tumor suppressor p53 in Filipino breast cancer: results and perspectives in molecular pathology and epidemiology

    International Nuclear Information System (INIS)

    Deocaris, Custer C.

    2000-04-01

    The p53 tumor suppressor is by far the most widely mutated gene in human cancers. p53 encodes a 53-kDa phosphoprotein, transcription-activator whose targets include genes and gene products that orchestrate genomic stability, cellular response to DNA damage, cell cycle progression apoptosis and aging (senescence). Analysis of the p53 gene profile has previously resulted in identifying several cancer-causative factors in the human setting, as well as, in creating a unique molecular profile of a tumor useful in the design of tailored-therapies for individual cancer patients. Our results in screening for p53 abnormalities in 140 Filipino patients with primary breast lesions confined from 1997-1998 in 5 major hospitals in Manila reveal that p53 plays an important role in the development and progression of breast cancer in at least 48% of all cases. Two methods of p53 analysis are employed, enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction-temporal temperature gradient electrophoresis (PCR-TTGE). Inter-comparisons of method exhibit 63.3% concordance in 21 fresh breast carcinoma samples, with ELISA demonstrating 14% false-positives and 10% false-negatives. Only mutations in exon 7 (p=0.063) in the tumor samples how significant correlation with abnormal cellular elevation of p53. PCR-TTGE screening in a large series of 140 patients show that most genetic lesions are localized in exons 5 (41% of the total cases) and 6 (27% of the total cases). No mutations are, however, detected in the transactivation (exons 2-4) and oligomerization (exons 10-11) domains. Invasive carcinomas (stages II and III) are characterized with more frequent and diverse genetic alterations compared with benign tumors, most significantly at exon 5B (p=0.066) and at independently multiple sites (p=0.066). Earlier-onset cases (age of diagnosis < 50 yrs), known to be more clinico-pathologically aggressive, are diagnosed harboring more frequent p53 mutations centered at exon 7 (p=0

  12. Mutational myriad of tumor suppressor p53 in Filipino breast cancer: results and perspectives in molecular pathology and epidemiology

    Energy Technology Data Exchange (ETDEWEB)

    Deocaris, Custer C

    2000-04-01

    The p53 tumor suppressor is by far the most widely mutated gene in human cancers. p53 encodes a 53-kDa phosphoprotein, transcription-activator whose targets include genes and gene products that orchestrate genomic stability, cellular response to DNA damage, cell cycle progression apoptosis and aging (senescence). Analysis of the p53 gene profile has previously resulted in identifying several cancer-causative factors in the human setting, as well as, in creating a unique molecular profile of a tumor useful in the design of tailored-therapies for individual cancer patients. Our results in screening for p53 abnormalities in 140 Filipino patients with primary breast lesions confined from 1997-1998 in 5 major hospitals in Manila reveal that p53 plays an important role in the development and progression of breast cancer in at least 48% of all cases. Two methods of p53 analysis are employed, enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction-temporal temperature gradient electrophoresis (PCR-TTGE). Inter-comparisons of method exhibit 63.3% concordance in 21 fresh breast carcinoma samples, with ELISA demonstrating 14% false-positives and 10% false-negatives. Only mutations in exon 7 (p=0.063) in the tumor samples how significant correlation with abnormal cellular elevation of p53. PCR-TTGE screening in a large series of 140 patients show that most genetic lesions are localized in exons 5 (41% of the total cases) and 6 (27% of the total cases). No mutations are, however, detected in the transactivation (exons 2-4) and oligomerization (exons 10-11) domains. Invasive carcinomas (stages II and III) are characterized with more frequent and diverse genetic alterations compared with benign tumors, most significantly at exon 5B (p=0.066) and at independently multiple sites (p=0.066). Earlier-onset cases (age of diagnosis < 50 yrs), known to be more clinico-pathologically aggressive, are diagnosed harboring more frequent p53 mutations centered at exon 7 (p=0

  13. Overexpression of the p53 tumor suppressor gene product in primary lung adenocarcinomas is associated with cigarette smoking

    NARCIS (Netherlands)

    Westra, W. H.; Offerhaus, G. J.; Goodman, S. N.; Slebos, R. J.; Polak, M.; Baas, I. O.; Rodenhuis, S.; Hruban, R. H.

    1993-01-01

    Mutations in the p53 tumor suppressor gene are frequently observed in primary lung adenocarcinomas, suggesting that these mutations are critical events in the malignant transformation of airway cells. These mutations are often associated with stabilization of the p53 gene product, resulting in the

  14. Deregulation of p53 and RB Transcriptional Control Leads to Overexpression of DNA Methyltransferases in Lung Cancer

    Directory of Open Access Journals (Sweden)

    Yen-An Tang

    2014-06-01

    Conclusions: This study provides cell and clinical evidence that p53 and RB pathways transcriptionally repress DNMT expression. Normal expression of DNMT3A, RB and MDM2 proteins can be a biomarker for good prognosis in lung cancer.

  15. Germ line p53 mutations in a familial syndrome of breast cancer, sarcomas, and other neoplasms.

    Science.gov (United States)

    Malkin, D; Li, F P; Strong, L C; Fraumeni, J F; Nelson, C E; Kim, D H; Kassel, J; Gryka, M A; Bischoff, F Z; Tainsky, M A

    1990-11-30

    Familial cancer syndromes have helped to define the role of tumor suppressor genes in the development of cancer. The dominantly inherited Li-Fraumeni syndrome (LFS) is of particular interest because of the diversity of childhood and adult tumors that occur in affected individuals. The rarity and high mortality of LFS precluded formal linkage analysis. The alternative approach was to select the most plausible candidate gene. The tumor suppressor gene, p53, was studied because of previous indications that this gene is inactivated in the sporadic (nonfamilial) forms of most cancers that are associated with LFS. Germ line p53 mutations have been detected in all five LFS families analyzed. These mutations do not produce amounts of mutant p53 protein expected to exert a trans-dominant loss of function effect on wild-type p53 protein. The frequency of germ line p53 mutations can now be examined in additional families with LFS, and in other cancer patients and families with clinical features that might be attributed to the mutation.

  16. Nanotized PPARα Overexpression Targeted to Hypertrophied Myocardium Improves Cardiac Function by Attenuating the p53-GSK3β-Mediated Mitochondrial Death Pathway.

    Science.gov (United States)

    Rana, Santanu; Datta, Ritwik; Chaudhuri, Ratul Datta; Chatterjee, Emeli; Chawla-Sarkar, Mamta; Sarkar, Sagartirtha

    2018-05-09

    Metabolic remodeling of cardiac muscles during pathological hypertrophy is characterized by downregulation of fatty acid oxidation (FAO) regulator, peroxisome proliferator-activated receptor alpha (PPARα). Thereby, we hypothesized that a cardiac-specific induction of PPARα might restore the FAO-related protein expression and resultant energy deficit. In the present study, consequences of PPARα augmentation were evaluated for amelioration of chronic oxidative stress, myocyte apoptosis, and cardiac function during pathological cardiac hypertrophy. Nanotized PPARα overexpression targeted to myocardium was done by a stearic acid-modified carboxymethyl-chitosan (CMC) conjugated to a 20-mer myocyte-targeted peptide (CMCP). Overexpression of PPARα ameliorated pathological hypertrophy and improved cardiac function. Augmented PPARα in hypertrophied myocytes revealed downregulated p53 acetylation (lys 382), leading to reduced apoptosis. Such cells showed increased binding of PPARα with p53 that in turn reduced interaction of p53 with glycogen synthase kinase-3β (GSK3β), which upregulated inactive phospho-GSK3β (serine [Ser]9) expression within mitochondrial protein fraction. Altogether, the altered molecular milieu in PPARα-overexpressed hypertrophy groups restored mitochondrial structure and function both in vitro and in vivo. Cardiomyocyte-targeted overexpression of a protein of interest (PPARα) by nanotized plasmid has been described for the first time in this study. Our data provide a novel insight towards regression of pathological hypertrophy by ameliorating mitochondrial oxidative stress in targeted PPARα-overexpressed myocardium. PPARα-overexpression during pathological hypertrophy showed substantial betterment of mitochondrial structure and function, along with downregulated apoptosis. Myocardium-targeted overexpression of PPARα during pathological cardiac hypertrophy led to an overall improvement of cardiac energy deficit and subsequent cardiac

  17. P53 Mutation Analysis to Predict Tumor Response in Patients Undergoing Neoadjuvant Treatment for Locally Advanced Breast Cancer

    Science.gov (United States)

    2006-10-01

    then sequenced (for GeneChip- positiv SSCP (for GeneChip-negative). We have received a total of 43 core breast biopsy DNA samples from the UNC... quantitative luciferase reporter. Both reporters exploit a “rheostatable” promoter for p53 expression and utilize the “delitto perfetto” in vivo... quantitative luciferase-based assay is also being used to characterize the altered function sistent an tion T mutants in greater detail. Preliminary

  18. Determination of HER2 and p53 Mutations by Sequence Analysis Method and EGFR/Chromosome 7 Gene Status by Fluorescence in Situ Hybridization for the Predilection of Targeted Therapy Modalities in Immunohistochemically Triple Negative Breast Carcinomas in Turkish Population.

    Science.gov (United States)

    Pala, Emel Ebru; Bayol, Umit; Keskin, Elif Usturali; Ozguzer, Alp; Kucuk, Ulku; Ozer, Ozge; Koc, Altug

    2015-09-01

    Triple negative breast cancer (TNBC), an agressive subtype accounts nearly 15 % of all breast carcinomas. Conventional chemotherapy is the only treatment modality thus new, effective targeted therapy methods have been investigated. Epidermal growth factor receptor (EGFR) inhibitors give hope according to the recent studies results. Also therapeutic agents have been tried against aberrant p53 signal activity as TNBC show high p53 mutation rates. Our aim was to detect the incidence of mutations/amplifications identified in TNBC in our population. Here we used sequence analysis to detect HER2 (exon 18-23), p53 (exon 5-8) mutations; fluorescence in situ hybridization (FISH) method to analyse EGFR/chromosome 7 centromere gene status in 82 immunohistochemically TNBC. Basaloid phenotype was identified in 49 (59.8 %) patients. EGFR amplification was noted in 5 cases (6.1 %). All EGFR amplified cases showed EGFR overexpression by immunohistochemistry (IHC). p53 mutations were identified in 33 (40.2 %) cases. Almost 60 % of the basal like breast cancer cases showed p53 mutation. Only one case showed HER2 mutation (exon 20:g.36830_3). Our results showed that gene amplification is not the unique mechanism in EGFR overexpression. IHC might be used in the decision of anti-EGFR therapy in routine practice. p53 mutation rate was lower than the rates reported in the literature probably due to ethnic differences and low sensitivity of sanger sequences in general mutation screening. We also established the rarity of HER2 mutation in TNBC. In conclusion EGFR and p53 are the major targets in TNBC also for our population.

  19. Over-expression of p53 mutants in LNCaP cells alters tumor growth and angiogenesis in vivo

    International Nuclear Information System (INIS)

    Perryman, L.A.; Blair, J.M.; Kingsley, E.A.; Szymanska, B.; Ow, K.T.; Wen, V.W.; MacKenzie, K.L.; Vermeulen, P.B.; Jackson, P.; Russell, P.J.

    2006-01-01

    This study has investigated the impact of three specific dominant-negative p53 mutants (F134L, M237L, and R273H) on tumorigenesis by LNCaP prostate cancer cells. Mutant p53 proteins were associated with an increased subcutaneous 'take rate' in NOD-SCID mice, and increased production of PSA. Tumors expressing F134L and R273H grew slower than controls, and were associated with decreased necrosis and apoptosis, but not hypoxia. Interestingly, hypoxia levels were increased in tumors expressing M237L. There was less proliferation in F134L-bearing tumors compared to control, but this was not statistically significant. Angiogenesis was decreased in tumors expressing F134L and R273H compared with M237L, or controls. Conditioned medium from F134L tumors inhibited growth of normal human umbilical-vein endothelial cells but not telomerase-immortalized bone marrow endothelial cells. F134L tumor supernatants showed lower levels of VEGF and endostatin compared with supernatants from tumors expressing other mutants. Our results support the possibility that decreased angiogenesis might account for reduced growth rate of tumor cells expressing the F134L p53 mutation

  20. Integration of Genomic, Biologic, and Chemical Approaches to Target p53 Loss and Gain-of-Function in Triple Negative Breast Cancer

    Science.gov (United States)

    2016-09-01

    in this progress report: p53 triple-negative breast cancer subtypes gene expression somatic cell genetics CRISPR / Cas 3. ACCOMPLISHMENTS Major...report, we described the creation of an isogenic p53 mutant TNBC cell line panel using CRISPR / Cas -mediated genome editing8 and the resultant...LOF null state. To validate that mutant p53 is directly responsible for this altered transcription, we will use the same CRISPR -mediated genome

  1. Breastfeeding and Immunohistochemical Expression of ki-67, p53 and BCL2 in Infiltrating Lobular Breast Carcinoma.

    Directory of Open Access Journals (Sweden)

    Angel Gonzalez-Sistal

    Full Text Available Invasive lobular breast carcinoma is the second most common type of breast cancer after invasive ductal carcinoma. According to the American Cancer Society, more than 180,000 women in the United States find out they have invasive breast cancer each year. Personal history of breast cancer and certain changes in the breast are correlated with an increased breast cancer risk. The aim of this work was to analyze breastfeeding in patients with infiltrating lobular breast carcinoma, in relation with: 1 clinicopathological parameters, 2 hormonal receptors and 3 tissue-based tumor markers.The study included 80 women with ILC, 46 of which had breastfeed their children. Analyzed parameters were: age, tumor size, axillary lymph node (N, distant metastasis (M, histological grade (HG, estrogen receptor (ER, progesterone receptor (PR, androgen receptor (AR, Ki-67, p53 and BCL2.ILC of non-lactating women showed a larger (p = 0.009, lymph node involvement (p = 0.051 and distant metastasis (p = 0.060. They were also more proliferative tumors measured by Ki-67 (p = 0.053. Breastfeeding history did not influence the subsequent behavior of the tumor regardless of histological subtype.Lactation seems to influence the biological characteristics of ILC defining a subgroup with more tumor size, axillary lymph node involvement, distant metastasis and higher proliferation measured by ki-67 expression.

  2. Feasibility of Breast Conservation after Neoadjuvant Chemotherapy in 58 Patients with Locally Advanced Breast Cancer Using p53 and MDRI Genes as Predictors of Response

    International Nuclear Information System (INIS)

    Elsawy, W.H.; Abdel Kader, M.; Abdulla, M.H.

    2002-01-01

    The aim of this prospective trial was to evaluate the feasibility and outcome of breast conservation therapy for patients with locally advanced breast cancer after neoadjuvant chemotherapy. We studied also the value of p53 and MDR1 as predictors to neoadjuvant chemotherapy. Patients and methods: Bet ween August 1997 and May 2000, 58 patients with locally advanced breast carcinoma (stages IlIA and lllB) completed treatment consisting of 5 fluorouracil 600 mg/m 2 , epirubicin 60 mg/m 2 and cyclophosphamide 600 mg/m 2 (FEC) administered intravenously, at intervals of 3 weeks. The number of cycles of chemotherapy given depended on the clinical tumor response. Surgery (local excision if sufficiently down staged, or mastectomy if not, both with axillary dissection) was performed. Surgery was followed by radiation therapy and 4 more cycles of FEC chemotherapy as an adjuvant therapy. P53 and MDR1 were assessed in the initial tissue biopsy by means of reverse transcriptase-mediated polymerase chain reaction (RT-PCR). p53 and MDR1 findings were correlated with treatment response and linkage between p53 function and cellular response was assessed by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Results: The overall response (CR+PR) was 87.9%, with a clinical complete response rate of 29.3%. Six patients had a pathological complete response and 10 patients had only minimal residual disease. Median followup from the start of chemotherapy was 24 months (range 6 to 40). Twenty two patients (43%) underwent BCS with actuarial 3-year disease-free and overall survival of 58% and 75% respectively. Cosmetic results were good to excellent in 77.2% of the patients. Modified radical mastectomy was done in 29/51 (56.9%) patients with actuarial 3 year disease-free and overall survival of 60% and 78% respectively.In 13 out of 58 patients (22.4%), p53 mutations could be identified, including eight point mutations, three minor deletions and two complex deletions

  3. Characterization of Two Novel Oncogenic Pathways Collaborating With Loss of P53 or Activated Neu in Mouse Models of Breast Cancer

    National Research Council Canada - National Science Library

    Lu, Jianrong; Leder, Philip

    2005-01-01

    Cancer develops through accumulation of multiple genetic mutations. Loss of tumor suppressor gene p53 and activation of oncogene Neu/ErbB2 are among the most frequent genetic alterations in human breast cancer...

  4. In squamous cell carcinoma of the vulva, overexpression of p53 is a late event and neither p53 nor mdm2 expression is a useful marker to predict lymph node metastases

    NARCIS (Netherlands)

    Emanuels, AG; Koudstaal, J; Burger, MPM; Hollema, H

    To offer more tailored treatment to individual patients with squamous cell carcinoma of the vulval more accurate prediction of lymph node metastases is required. As p53 and mdm2 are genes known to be involved in the development of other tumours, we studied expression of p53 and mdm2 in

  5. Detection of ATM germline variants by the p53 mitotic centrosomal localization test in BRCA1/2-negative patients with early-onset breast cancer.

    Science.gov (United States)

    Prodosmo, Andrea; Buffone, Amelia; Mattioni, Manlio; Barnabei, Agnese; Persichetti, Agnese; De Leo, Aurora; Appetecchia, Marialuisa; Nicolussi, Arianna; Coppa, Anna; Sciacchitano, Salvatore; Giordano, Carolina; Pinnarò, Paola; Sanguineti, Giuseppe; Strigari, Lidia; Alessandrini, Gabriele; Facciolo, Francesco; Cosimelli, Maurizio; Grazi, Gian Luca; Corrado, Giacomo; Vizza, Enrico; Giannini, Giuseppe; Soddu, Silvia

    2016-09-06

    Variant ATM heterozygotes have an increased risk of developing cancer, cardiovascular diseases, and diabetes. Costs and time of sequencing and ATM variant complexity make large-scale, general population screenings not cost-effective yet. Recently, we developed a straightforward, rapid, and inexpensive test based on p53 mitotic centrosomal localization (p53-MCL) in peripheral blood mononuclear cells (PBMCs) that diagnoses mutant ATM zygosity and recognizes tumor-associated ATM polymorphisms. Fresh PBMCs from 496 cancer patients were analyzed by p53-MCL: 90 cases with familial BRCA1/2-positive and -negative breast and/or ovarian cancer, 337 with sporadic cancers (ovarian, lung, colon, and post-menopausal breast cancers), and 69 with breast/thyroid cancer. Variants were confirmed by ATM sequencing. A total of seven individuals with ATM variants were identified, 5/65 (7.7 %) in breast cancer cases of familial breast and/or ovarian cancer and 2/69 (2.9 %) in breast/thyroid cancer. No variant ATM carriers were found among the other cancer cases. Excluding a single case in which both BRCA1 and ATM were mutated, no p53-MCL alterations were observed in BRCA1/2-positive cases. These data validate p53-MCL as reliable and specific test for germline ATM variants, confirm ATM as breast cancer susceptibility gene, and highlight a possible association with breast/thyroid cancers.

  6. The role of the expression of bcl-2, p53 gene in tamoxifen-induced apoptosis of breast cancer cells and its relationship with hormone receptor status

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Woo Chul; Ham, Yong Ho [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1998-01-01

    To investigate the relationship of bcl-2, p53, ER and tamoxifen-induced apoptosis of breast cancer cells, MCF-7 (ER+/bcl-2+/p53-) and MB MDA 468 (ER-/bcl-2-/p53+) cell line were cultured in estrogen-free condition. E2(10`-`9M) and tamoxifen (10`-`5M) were added to the media. The changes of bcl-2 and mutant p53 protein were checked by Western blot and apoptosis were measured by flowcytometry. In MCF-7 cells, we found that treatment with tamoxifen resulted in a decrease in bcl-2 protein level, but produced no change in mutant p53. In MB MDA 468 cell however, there were no changes of bcl-2 and mutant p53 protein level when E2 or tamoxifen were added. Apoptotic cells increased with time-dependent pattern when tamoxifen was added to MCF-7 cells. According to these result, ER+/blc-2+/mutant p53- cells, when treated with tamoxifen, were converted into bcl-2/mutant p53- cells which were more prone to apoptosis than bcl-2-/mutant p53+ cells. The paradoxical correlation of bcl-2 and ER which had been observed in clinical studies might be explained with this results and bcl-2 protein seems to be one of important factors that can predict the effect of hormone therapy. (author). 26 refs., 5 figs

  7. The role of the expression of bcl-2, p53 gene in tamoxifen-induced apoptosis of breast cancer cells and its relationship with hormone receptor status

    International Nuclear Information System (INIS)

    Noh, Woo Chul; Ham, Yong Ho

    1998-01-01

    To investigate the relationship of bcl-2, p53, ER and tamoxifen-induced apoptosis of breast cancer cells, MCF-7 (ER+/bcl-2+/p53-) and MB MDA 468 (ER-/bcl-2-/p53+) cell line were cultured in estrogen-free condition. E2(10'-'9M) and tamoxifen (10'-'5M) were added to the media. The changes of bcl-2 and mutant p53 protein were checked by Western blot and apoptosis were measured by flowcytometry. In MCF-7 cells, we found that treatment with tamoxifen resulted in a decrease in bcl-2 protein level, but produced no change in mutant p53. In MB MDA 468 cell however, there were no changes of bcl-2 and mutant p53 protein level when E2 or tamoxifen were added. Apoptotic cells increased with time-dependent pattern when tamoxifen was added to MCF-7 cells. According to these result, ER+/blc-2+/mutant p53- cells, when treated with tamoxifen, were converted into bcl-2/mutant p53- cells which were more prone to apoptosis than bcl-2-/mutant p53+ cells. The paradoxical correlation of bcl-2 and ER which had been observed in clinical studies might be explained with this results and bcl-2 protein seems to be one of important factors that can predict the effect of hormone therapy. (author). 26 refs., 5 figs

  8. NUCKS overexpression in breast cancer

    Directory of Open Access Journals (Sweden)

    Kittas Christos

    2009-08-01

    Full Text Available Abstract Background NUCKS (Nuclear, Casein Kinase and Cyclin-dependent Kinase Substrate is a nuclear, DNA-binding and highly phosphorylated protein. A number of reports show that NUCKS is highly expressed on the level of mRNA in several human cancers, including breast cancer. In this work, NUCKS expression on both RNA and protein levels was studied in breast tissue biopsies consisted of invasive carcinomas, intraductal proliferative lesions, benign epithelial proliferations and fibroadenomas, as well as in primary cultures derived from the above biopsies. Specifically, in order to evaluate the level of NUCKS protein in correlation with the histopathological features of breast disease, immunohistochemistry was employed on paraffin sections of breast biopsies of the above types. In addition, NUCKS expression was studied by means of Reverse Transcription PCR (RT-PCR, real-time PCR (qRT-PCR and Western immunoblot analyses in the primary cell cultures developed from the same biopsies. Results The immunohistochemical Results showed intense NUCKS staining mostly in grade I and II breast carcinomas compared to normal tissues. Furthermore, NUCKS was moderate expressed in benign epithelial proliferations, such as adenosis and sclerosing adenosis, and highly expressed in intraductal lesions, specifically in ductal carcinomas in situ (DCIS. It is worth noting that all the fibroadenoma tissues examined were negative for NUCKS staining. RT-PCR and qRT-PCR showed an increase of NUCKS expression in cells derived from primary cultures of proliferative lesions and cancerous tissues compared to the ones derived from normal breast tissues and fibroadenomas. This increase was also confirmed by Western immunoblot analysis. Although NUCKS is a cell cycle related protein, its expression does not correlate with Ki67 expression, neither in tissue sections nor in primary cell cultures. Conclusion The results show overexpression of the NUCKS protein in a number of non

  9. MiR-192-Mediated Positive Feedback Loop Controls the Robustness of Stress-Induced p53 Oscillations in Breast Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Richard Moore

    2015-12-01

    Full Text Available The p53 tumor suppressor protein plays a critical role in cellular stress and cancer prevention. A number of post-transcriptional regulators, termed microRNAs, are closely connected with the p53-mediated cellular networks. While the molecular interactions among p53 and microRNAs have emerged, a systems-level understanding of the regulatory mechanism and the role of microRNAs-forming feedback loops with the p53 core remains elusive. Here we have identified from literature that there exist three classes of microRNA-mediated feedback loops revolving around p53, all with the nature of positive feedback coincidentally. To explore the relationship between the cellular performance of p53 with the microRNA feedback pathways, we developed a mathematical model of the core p53-MDM2 module coupled with three microRNA-mediated positive feedback loops involving miR-192, miR-34a, and miR-29a. Simulations and bifurcation analysis in relationship to extrinsic noise reproduce the oscillatory behavior of p53 under DNA damage in single cells, and notably show that specific microRNA abrogation can disrupt the wild-type cellular phenotype when the ubiquitous cell-to-cell variability is taken into account. To assess these in silico results we conducted microRNA-perturbation experiments in MCF7 breast cancer cells. Time-lapse microscopy of cell-population behavior in response to DNA double-strand breaks, together with image classification of single-cell phenotypes across a population, confirmed that the cellular p53 oscillations are compromised after miR-192 perturbations, matching well with the model predictions. Our study via modeling in combination with quantitative experiments provides new evidence on the role of microRNA-mediated positive feedback loops in conferring robustness to the system performance of stress-induced response of p53.

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

    International Nuclear Information System (INIS)

    Tsutsui, Shinichi; Yasuda, Kazuhiro; Suzuki, Kosuke; Takeuchi, Hideya; Nishizaki, Takashi; Higashi, Hidefumi; Era, Shoichi

    2006-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Nishizaki Takashi

    2006-07-01

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

  12. Mir-1307 regulates cisplatin resistance by targeting Mdm4 in breast cancer expressing wild type P53.

    Science.gov (United States)

    Wang, Xinyan; Zhu, Jianwei

    2018-04-26

    Many chemotherapy regimens are used to treat breast cancer; however, breast cancer cells often develop drug resistance that usually leads to relapse and poor prognosis. MicroRNAs (miRNAs) are short non-coding RNA molecules that post-transcriptionally regulate gene expression and play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. We investigated the roles of miRNAs in the development of drug resistance in human breast cancer cells. MiRNA expression was detected in human breast cancer cell lines MCF-7 and MDA-MB-468 via real time PCR; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide, cell viability, colony formation, and luciferase reporter gene assays; Western blot; and immunohistochemistry. MiR-1307 was downregulated while MDM4 was upregulated in MCF-7/cisplatin (CDDP) and MDA-MB-468/CDDP cells compared with parental MCF-7 and MDA-MB-468 cells. in vitro drug sensitivity assay demonstrated that overexpression of miR-1307 sensitized MCF-7/CDDP cells to CDDP. Luciferase activity assay with a reporter containing sequences from the 3' untranslated region of Mdm4 in MCF-7/CDDP cells suggested that Mdm4 was the direct target gene of miR-1307. Ectopic miR-1307 expression reduced the MDM4 protein level and sensitized MCF-7/CDDP cells to CDDP-induced apoptosis. Our findings suggest, for the first time, that miR-1307 could play a role in the development of CDDP resistance in breast cancer, at least in part by modulating apoptosis by targeting Mdm4. © 2018 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

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

    Science.gov (United States)

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

    2010-08-27

    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.

  14. 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.

  15. Skp2B overexpression alters a prohibitin-p53 axis and the transcription of PAPP-A, the protease of insulin-like growth factor binding protein 4.

    Directory of Open Access Journals (Sweden)

    Harish Chander

    Full Text Available We previously reported that the degradation of prohibitin by the SCF(Skp2B ubiquitin ligase results in a defect in the activity of p53. We also reported that MMTV-Skp2B transgenic mice develop mammary gland tumors that are characterized by an increased proteolytic cleavage of the insulin-like growth factor binding protein 4 (IGFBP-4, an inhibitor of IGF signaling. However, whether a link exists between a defect in p53 activity and proteolysis of IGFBP-4 was not established.We analyzed the levels of pregnancy-associated plasma protein A (PAPP-A, the protease of IGFBP-4, in MMTV-Skp2B transgenic mice and found that PAPP-A levels are elevated. Further, we found a p53 binding site in intron 1 of the PAPP-A gene and that both wild type and mutant p53 bind to this site. However, binding of wild type p53 results in the transcriptional repression of PAPP-A, while binding of mutant p53 results in the transcriptional activation of PAPP-A. Since MMTV-Skp2B mice express wild type p53 and yet show elevated levels of PAPP-A, at first, these observations appeared contradictory. However, further analysis revealed that the defect in p53 activity in Skp2B overexpressing cells does not only abolish the activity of wild type of p53 but actually mimics that of mutant p53. Our results suggest that in absence of prohibitin, the half-life of p53 is increased and like mutant p53, the conformation of p53 is denatured.These observations revealed a novel function of prohibitin as a chaperone of p53. Further, they suggest that binding of denatured p53 in intron 1 causes an enhancer effect and increases the transcription of PAPP-A. Therefore, these findings indicate that the defect in p53 function and the increased proteolysis of IGFBP-4, we had observed, represent two components of the same pathway, which contributes to the oncogenic function of Skp2B.

  16. p53 inactivation decreases dependence on estrogen/ERK signalling for proliferation but promotes EMT and susceptility to 3-bromopyruvate in ERα+ breast cancer MCF-7 cells.

    Science.gov (United States)

    Rieber, Manuel; Strasberg-Rieber, Mary

    2014-03-15

    Most breast cancers express the estrogen receptor alpha (ERα(+)), harbor wt TP53, depend on estrogen/ERK signalling for proliferation, and respond to anti-estrogens. However, concomittant activation of the epidermal growth factor receptor (EGFR)/MEK pathway promotes resistance by decreasing estrogen dependence. Previously, we showed that retroviral transduction of mutant p53 R175H into wt TP53 ERα(+) MCF-7 cells induces epidermal growth factor (EGF)-independent proliferation, activation of the EGF receptor (p-EGFR) and some characteristics of epithelial-mesenchymal transition (EMT). To investigate whether p53 inactivation augments ERα(+) cell proliferation in response to restrictive estradiol, chemical MEK inhibition or metabolic inhibitors. Introduction of mutant p53 R175H lowered expression of p53-dependent PUMA and p21WAF1, decreased E-cadherin and cytokeratin 18 associated with EMT, but increased the % of proliferating ERα(+)/Ki67 cells, diminishing estrogen dependence. These cells also exhibited higher proliferation in the presence of MEK-inhibitor UO126, reciprocally correlating with preferential susceptibility to the pyruvate analog 3-bromopyruvate (3-BrPA) without a comparable response to 2-deoxyglucose. p53 siRNA silencing by electroporation in wt TP53 MCF-7 cells also decreased estrogen dependence and response to MEK inhibition, while also conferring susceptibility to 3-BrPA. (a) ERα(+) breast cancer cells dysfunctional for TP53 which proliferate irrespective of low estrogen and chemical MEK inhibition are likely to increase metabolic consumption becoming increasingly susceptible to 3-BrPA; (b) targeting the pyruvate pathway may improve response to endocrine therapy in ERα(+) breast cancer with p53 dysfunction. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Impact of BCL2 and p53 on postmastectomy radiotherapy response in high-risk breast cancer. A subgroup analysis of DBCG82 b and c

    International Nuclear Information System (INIS)

    Kyndi, M.; Alsner, J.; Nielsen, H.M.; Overgaard, J.; Soerensen, F.B.; Knudsen, H.; Overgaard, M.

    2008-01-01

    Purpose. To examine p53 and BCL2 expression in high-risk breast cancer patients randomized to postmastectomy radiotherapy (PMRT). Patients and methods. The present analysis included 1 000 of 3 083 high-risk breast cancer patients randomly assigned to PMRT in the DBCG82 b and c studies. Tissue microarray sections were stained with immunohistochemistry for p53 and BCL2. Median potential follow-up was 17 years. Clinical endpoints were locoregional recurrence (LRR), distant metastases (DM), overall mortality, and overall survival (OS). Statistical analyses included Kappa statistics, χ2 or exact tests, Kaplan-Meier probability plots, Log-rank test, and Cox univariate and multivariate regression analyses. Results. p53 accumulation was not significantly associated with increased overall mortality, DM or LRR probability in univariate or multivariate Cox regression analyses. Kaplan-Meier probability plots showed reduced OS and improved DM and LRR probabilities after PMRT within subgroups of both p53 negative and p53 positive patients. Negative BCL2 expression was significantly associated with increased overall mortality, DM and LRR probability in multivariate Cox regression analyses. Kaplan-Meier probability plots showed a significantly improved overall survival after PMRT for the BCL2 positive subgroup, whereas practically no survival improvement was seen after PMRT for the BCL2 negative subgroup. In multivariate analysis of OS, however, no significant interaction was found between BCL2 and randomization status. Significant reductions in LRR probability after PMRT were recorded within both the BCL2 positive and BCL2 negative subgroups. Conclusion. p53 was not associated with survival after radiotherapy in high-risk breast cancer, but BCL2 might be

  18. Environmental Exposures, Genetic Polymorphisms and p53 Mutational Spectra in a Case-Control Study of Breast Cancer

    National Research Council Canada - National Science Library

    Shields, eter

    1999-01-01

    .... Other genetic analyses are completed for MEH3, MEH4, CYP2D6, GSTMl, GST-T and CYP1A1. We have been validating a p53 mutational spectra detection technology using the Affymetrix gene chip array...

  19. Survival of ovarian cancer patients overexpressing the tumour antigen p53 is diminished in case of MHC class I down-regulation

    NARCIS (Netherlands)

    Leffers, Ninke; Lambeck, Annechien J. A.; de Graeff, Pauline; Bijlsma, Astrid Y.; Daemen, Toos; van der Zee, Ate G. J.; Nijman, Hans W.

    Objectives. The adaptive immune system seems to play an essential role in the natural course of ovarian cancer. Aim of this study was to establish whether disease-specific survival for patients expressing the tumour antigen p53 is influenced by MHC class I expression or the presence of p53

  20. Genotyping of BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes in a male patient with secondary breast cancer

    International Nuclear Information System (INIS)

    Vodusek, Ana Lina; Novakovic, Srdjan; Stegel, Vida; Jereb, Berta

    2011-01-01

    Some tumour suppressor genes (BRCA2) and mismatch repair genes (MSH2, MLH1) are correlated with an increased risk for male breast cancer. Our patient developed secondary breast cancer after the treatment for Hodgkin’s disease in childhood. DNA was isolated from the patients’ blood and screened for mutations, polymorphisms and variants in BRCA1, BRCA2, p53, CDKN2A, MLH1 and MSH2 genes. We found no mutations but common polymorphisms, and three variants in mismatch repair genes. Nucleotide variants c.2006-6T>C and p.G322D in MSH2 might be correlated with male breast cancer

  1. Mortality risk of black women and white women with invasive breast cancer by hormone receptors, HER2, and p53 status

    International Nuclear Information System (INIS)

    Ma, Huiyan; Folger, Suzanne G; Simon, Michael S; Sullivan-Halley, Jane; Press, Michael F; Bernstein, Leslie; Lu, Yani; Malone, Kathleen E; Marchbanks, Polly A; Deapen, Dennis M; Spirtas, Robert; Burkman, Ronald T; Strom, Brian L; McDonald, Jill A

    2013-01-01

    Black women are more likely than white women to have an aggressive subtype of breast cancer that is associated with higher mortality and this may contribute to the observed black-white difference in mortality. However, few studies have investigated the black-white disparity in mortality risk stratified by breast cancer subtype, defined by estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status. Furthermore, it is not known whether additional consideration of p53 protein status influences black-white differences in mortality risk observed when considering subtypes defined by ER, PR and HER2 status. Four biomarkers were assessed by immunohistochemistry in paraffin-embedded breast tumor tissue from 1,204 (523 black, 681 white) women with invasive breast cancer, aged 35–64 years at diagnosis, who accrued a median of 10 years’ follow-up. Multivariable Cox proportional hazards regression models were fit to assess subtype-specific black-white differences in mortality risk. No black-white differences in mortality risk were observed for women with triple negative (ER-negative [ER-], PR-, and HER2-) subtype. However, older (50–64 years) black women had greater overall mortality risk than older white women if they had been diagnosed with luminal A (ER-positive [ER+] or PR+ plus HER2-) breast cancer (all-cause hazard ratio, HR, 1.88; 95% confidence interval, CI, 1.18 to 2.99; breast cancer-specific HR, 1.51; 95% CI, 0.83 to 2.74). This black-white difference among older women was further confined to those with luminal A/p53- tumors (all-cause HR, 2.22; 95% CI, 1.30 to 3.79; breast cancer-specific HR, 1.89; 95% CI, 0.93 to 3.86). Tests for homogeneity of race-specific HRs comparing luminal A to triple negative subtype and luminal A/p53- to luminal A/p53+ subtype did not achieve statistical significance, although statistical power was limited. Our findings suggest that the subtype-specific black-white difference in

  2. Characterization of Two Novel Oncogenic Pathways Collaborating With Loss of P53 or Activated Neu in Mouse Models of Breast Cancer

    National Research Council Canada - National Science Library

    Lu, Jianrong; Leder, Philip

    2005-01-01

    .... The viral integrations result in marked overexpression of a novel, naturally occurring Fbw4 short isoform, which is also spontaneously enriched in several mouse and human breast cancer cell lines...

  3. Impact of BCL2 and p53 on postmastectomy radiotherapy response in high-risk breast cancer. A subgroup analysis of DBCG82 b&c

    DEFF Research Database (Denmark)

    Kyndi, Marianne; Sørensen, Flemming Brandt; Knudsen, Helle

    2008-01-01

    -Meier probability plots showed a significantly improved overall survival after PMRT for the BCL2 positive subgroup, whereas practically no survival improvement was seen after PMRT for the BCL2 negative subgroup. In multivariate analysis of OS, however, no significant interaction was found between BCL2......PURPOSE: To examine p53 and BCL2 expression in high-risk breast cancer patients randomized to postmastectomy radiotherapy (PMRT). PATIENTS AND METHODS: The present analysis included 1 000 of 3 083 high-risk breast cancer patients randomly assigned to PMRT in the DBCG82 b&c studies. Tissue...... tests, Kaplan-Meier probability plots, Log-rank test, and Cox univariate and multivariate regression analyses. RESULTS: p53 accumulation was not significantly associated with increased overall mortality, DM or LRR probability in univariate or multivariate Cox regression analyses. Kaplan...

  4. Impact of BCL2 and p53 on postmastectomy radiotherapy response in high-risk breast cancer. A subgroup analysis of DBCG82 b

    DEFF Research Database (Denmark)

    Kyndi, M.; Sorensen, F.B.; Alsner, J.

    2008-01-01

    -Meier probability plots showed a significantly improved overall survival after PMRT for the BCL2 positive subgroup, whereas practically no survival improvement was seen after PMRT for the BCL2 negative subgroup. In multivariate analysis of OS, however, no significant interaction was found between BCL2......Purpose. To examine p53 and BCL2 expression in high-risk breast cancer patients randomized to postmastectomy radiotherapy (PMRT). Patients and methods. The present analysis included 1000 of 3 083 high-risk breast cancer patients randomly assigned to PMRT in the DBCG82 b&c studies. Tissue microarray......, Kaplan-Meier probability plots, Log-rank test, and Cox univariate and multivariate regression analyses. Results. p53 accumulation was not significantly associated with increased overall mortality, DM or LRR probability in univariate or multivariate Cox regression analyses. Kaplan-Meier probability plots...

  5. MEKK1 is a Novel Regulator of the Dmp1-Arf-p53 Pathway and Prognostic Indicator in Breast Cancer

    Science.gov (United States)

    2012-12-01

    hDMP1, INK4a/ARF, p53 or Hdm2 amplification. Kaplan -Meier analyses have been conducted to study the impact for the impact of loss or gain of each locus on...Palma P, Pellegrini S, Fina P et al. Mdm2 gene alterations and mdm2 protein expression in breast carcinomas. J Pathol 1995; 175: 31–38. 21 Turbin DA

  6. PEER REVIEW (Correlation between GATA-3, Ki67 and p53 expressions to Histopathology grading of Breast Cancer bin Makassar, Indonesia)

    OpenAIRE

    Islam, Andi Asadul

    2016-01-01

    - PEER REVIEW Judul karya Ilmiah (artikel): Correlation between GATA-3, Ki67 and p53 expressions to Histopathology grading of Breast Cancer bin Makassar, Indonesia : 9 Orang : Penulis Ketiga : a. Nama Jurnal : Cancer Research Journal b. Nomor ISSN : 2330-8192, E: 2330-8214 c. Volume,nomor, bulan, tahun : Volume 4, No. 3 Tahun 2016 d. Penerbit : Science PG e. DOI artikel (Jika ada) : 10.11648/j.crj .20160403.11 f. Alamat web Jurnal : www.sciencepublishingg...

  7. Role of P53 and BCL-2 in high-risk breast cancer patients treated with adjuvant anthracycline-based chemotherapy.

    Science.gov (United States)

    Mottolese, M; Benevolo, M; Del Monte, G; Buglioni, S; Papaldo, P; Nisticò, C; Di Filippo, F; Vasselli, S; Vici, P; Botti, C

    2000-12-01

    Adjuvant therapy has become an integral component of the managment of primary high-risk breast cancer patients. However, a considerable fraction of women receive no benefit from this treatment. This study investigates whether a number of biopathological factors can influence the outcome of patients submitted to adjuvant chemotherapy involving the use of high-dose epirubicin and cyclophosphamide. One hundred and fifty-seven primary breast cancer patients, considered at high risk according to the St. Gallen Meeting Consensus Conference, were evaluated immunohistochemically for estrogen, progesterone receptors, p53, bcl-2, HER-2/neu, and Ki-67, of which the results were correlated with patient outcome. Results obtained demonstrated that p53 is a significant predictor of disease-free survival (DFS P < 0.0001) and overall survival (OS P = 0.0002) both in ductal and lobular carcinomas, whereas bcl-2 expression seems to be of prognostic value only in lobular carcinomas (DFS P = 0.01; OS P = 0.02). This data indicates that in high-risk breast cancer patients the immunohistochemical evaluation of p53 and bcl-2 may be of clinical value in distinguishing different responses to adjuvant anthracycline-based chemotherapy.

  8. Regulation of p53 tetramerization and nuclear export by ARC.

    Science.gov (United States)

    Foo, Roger S-Y; Nam, Young-Jae; Ostreicher, Marc Jason; Metzl, Mark D; Whelan, Russell S; Peng, Chang-Fu; Ashton, Anthony W; Fu, Weimin; Mani, Kartik; Chin, Suet-Feung; Provenzano, Elena; Ellis, Ian; Figg, Nichola; Pinder, Sarah; Bennett, Martin R; Caldas, Carlos; Kitsis, Richard N

    2007-12-26

    Inactivation of the transcription factor p53 is central to carcinogenesis. Yet only approximately one-half of cancers have p53 loss-of-function mutations. Here, we demonstrate a mechanism for p53 inactivation by apoptosis repressor with caspase recruitment domain (ARC), a protein induced in multiple cancer cells. The direct binding in the nucleus of ARC to the p53 tetramerization domain inhibits p53 tetramerization. This exposes a nuclear export signal in p53, triggering Crm1-dependent relocation of p53 to the cytoplasm. Knockdown of endogenous ARC in breast cancer cells results in spontaneous tetramerization of endogenous p53, accumulation of p53 in the nucleus, and activation of endogenous p53 target genes. In primary human breast cancers with nuclear ARC, p53 is almost always WT. Conversely, nearly all breast cancers with mutant p53 lack nuclear ARC. We conclude that nuclear ARC is induced in cancer cells and negatively regulates p53.

  9. The ubiquitin peptidase UCHL1 induces G0/G1 cell cycle arrest and apoptosis through stabilizing p53 and is frequently silenced in breast cancer.

    Directory of Open Access Journals (Sweden)

    Tingxiu Xiang

    Full Text Available Breast cancer (BrCa is a complex disease driven by aberrant gene alterations and environmental factors. Recent studies reveal that abnormal epigenetic gene regulation also plays an important role in its pathogenesis. Ubiquitin carboxyl- terminal esterase L1 (UCHL1 is a tumor suppressor silenced by promoter methylation in multiple cancers, but its role and alterations in breast tumorigenesis remain unclear.We found that UCHL1 was frequently downregulated or silenced in breast cancer cell lines and tumor tissues, but readily expressed in normal breast tissues and mammary epithelial cells. Promoter methylation of UCHL1 was detected in 9 of 10 breast cancer cell lines (90% and 53 of 66 (80% primary tumors, but rarely in normal breast tissues, which was statistically correlated with advanced clinical stage and progesterone receptor status. Pharmacologic demethylation reactivated UCHL1 expression along with concomitant promoter demethylation. Ectopic expression of UCHL1 significantly suppressed the colony formation and proliferation of breast tumor cells, through inducing G0/G1 cell cycle arrest and apoptosis. Subcellular localization study showed that UCHL1 increased cytoplasmic abundance of p53. We further found that UCHL1 induced p53 accumulation and reduced MDM2 protein level, and subsequently upregulated the expression of p21, as well as cleavage of caspase3 and PARP, but not in catalytic mutant UCHL1 C90S-expressed cells.UCHL1 exerts its tumor suppressive functions by inducing G0/G1cell cycle arrest and apoptosis in breast tumorigenesis, requiring its deubiquitinase activity. Its frequent silencing by promoter CpG methylation may serve as a potential tumor marker for breast cancer.

  10. Modulation of Cyclins, p53 and Mitogen-Activated Protein Kinases Signaling in Breast Cancer Cell Lines by 4-(3,4,5-Trimethoxyphenoxybenzoic Acid

    Directory of Open Access Journals (Sweden)

    Kuan-Han Lee

    2014-01-01

    Full Text Available Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxybenzoic acid (TMPBA and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC50 values of 5.9 and 7.9 µM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4',6-diamidino-2-phenylindole (DAPI nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP kinases, 5' adenosine monophosphate-activated protein kinase (AMPK, and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy.

  11. 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

  12. The Fanconi anemia pathway sensitizes to DNA alkylating agents by inducing JNK-p53-dependent mitochondrial apoptosis in breast cancer cells.

    Science.gov (United States)

    Zhao, Lin; Li, Yanlin; He, Miao; Song, Zhiguo; Lin, Shu; Yu, Zhaojin; Bai, Xuefeng; Wang, Enhua; Wei, Minjie

    2014-07-01

    The Fanconi anemia/BRCA (FA/BRCA) DNA damage repair pathway plays a pivotal role in the cellular response to DNA alkylating agents and greatly influences drug response in cancer treatment. However, the molecular mechanisms underlying the FA/BRCA pathway reversed resistance have received limited attention. In the present study, we investigated the effect of Fanconi anemia complementation group F protein (FANCF), a critical factor of the FA/BRCA pathway, on cancer cell apoptosis induced by DNA alkylating agents such as mitomycin c (MMC). We found that FANCF shRNA potentiated MMC-induced cytotoxicity and apoptosis in MCF-7 and MDA-MB-231 breast cancer cells. At a mechanistic level, FANCF shRNA downregulated the anti-apoptotic protein Bcl-2 and upregulated the pro-apoptotic protein Bax, accompanied by release of cyt-c and smac into the cytosol in MMC-treated cells. Furthermore, activation of caspase-3 and -9, other than caspase-8, cleavage of poly(ADP ribose) polymerase (PARP), and a decrease of mitochondrial membrane potential (MMP) indicated that involvement of the mitochondrial apoptotic pathway in FANCF silencing of MMC-treated breast cancer cells. A decrease in IAP family proteins XIAP and survivin were also observed following FANCF silencing in MMC-treated breast cancer cells. Notably, FANCF shRNA was able to increase p53 levels through activation of the JNK pathway in MMC-treated breast cancer cells. Furthermore, p53 inhibition using pifithrin-α abolished the induction of caspase-3 and PARP by FANCF shRNA and MMC, indicating that MMC-induced apoptosis is substantially enhanced by FANCF shRNA via p53-dependent mechanisms. To our knowledge, we provide new evidence for the potential application of FANCF as a chemosensitizer in breast cancer therapy.

  13. Low p53 Binding Protein 1 (53BP1) Expression Is Associated With Increased Local Recurrence in Breast Cancer Patients Treated With Breast-Conserving Surgery and Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Neboori, Hanmanth J.R. [Department of Radiation Oncology, Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Haffty, Bruce G., E-mail: hafftybg@umdnj.edu [Department of Radiation Oncology, The Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Wu Hao [Department of Radiation Oncology, Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Yang Qifeng [Department of Breast Surgery, Qilu Hospital, Shandong University, Ji' nan (China); Aly, Amal [Division of Medical Oncology, The Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Goyal, Sharad; Schiff, Devora [Department of Radiation Oncology, Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Moran, Meena S. [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT (United States); Golhar, Ryan [Department of Radiation Oncology, Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); Chen Chunxia; Moore, Dirk [Department of Biostatistics, The Cancer Institute of New Jersey and University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, NJ (United States); and others

    2012-08-01

    Purpose: To investigate whether the expression of p53 binding protein 1 (53BP1) has prognostic significance in a cohort of early-stage breast cancer patients treated with breast-conserving surgery and radiotherapy (BCS+RT). Methods and Materials: A tissue microarray of early-stage breast cancer treated with BCS+RT from a cohort of 514 women was assayed for 53BP1, estrogen receptor, progesterone receptor, and HER2 expression by immunohistochemistry. Through log-rank tests and univariate and multivariate models, the staining profile of each tumor was correlated with clinical endpoints, including ipsilateral breast recurrence-free survival (IBRFS), distant metastasis-free survival (DMFS), cause-specific survival (CSS), recurrence-free survival (RFS), and overall survival (OS). Results: Of the 477 (93%) evaluable tumors, 63 (13%) were scored as low. Low expression of 53BP1 was associated with worse outcomes for all endpoints studied, including 10-year IBRFS (76.8% vs. 90.5%; P=.01), OS (66.4% vs. 81.7%; P=.02), CSS (66.0% vs. 87.4%; P<.01), DMFS (55.9% vs. 87.0%; P<.01), and RFS (45.2% vs. 80.6%; P<.01). Multivariate analysis incorporating various clinico-pathologic markers and 53BP1 expression found that 53BP1 expression was again an independent predictor of all endpoints (IBRFS: P=.0254; OS: P=.0094; CSS: P=.0033; DMFS: P=.0006; RFS: P=.0002). Low 53BP1 expression was also found to correlate with triple-negative (TN) phenotype (P<.01). Furthermore, in subset analysis of all TN breast cancer, negative 53BP1 expression trended for lower IBRFS (72.3% vs. 93.9%; P=.0361) and was significant for worse DMFS (48.2% vs. 86.8%; P=.0035) and RFS (37.8% vs. 83.7%; P=.0014). Conclusion: Our data indicate that low 53BP1 expression is an independent prognostic indicator for local relapse among other endpoints in early-stage breast cancer and TN breast cancer patients treated with BCS+RT. These results should be verified in larger cohorts of patients to validate their clinical

  14. Low p53 Binding Protein 1 (53BP1) Expression Is Associated With Increased Local Recurrence in Breast Cancer Patients Treated With Breast-Conserving Surgery and Radiotherapy

    International Nuclear Information System (INIS)

    Neboori, Hanmanth J.R.; Haffty, Bruce G.; Wu Hao; Yang Qifeng; Aly, Amal; Goyal, Sharad; Schiff, Devora; Moran, Meena S.; Golhar, Ryan; Chen Chunxia; Moore, Dirk

    2012-01-01

    Purpose: To investigate whether the expression of p53 binding protein 1 (53BP1) has prognostic significance in a cohort of early-stage breast cancer patients treated with breast-conserving surgery and radiotherapy (BCS+RT). Methods and Materials: A tissue microarray of early-stage breast cancer treated with BCS+RT from a cohort of 514 women was assayed for 53BP1, estrogen receptor, progesterone receptor, and HER2 expression by immunohistochemistry. Through log–rank tests and univariate and multivariate models, the staining profile of each tumor was correlated with clinical endpoints, including ipsilateral breast recurrence–free survival (IBRFS), distant metastasis–free survival (DMFS), cause-specific survival (CSS), recurrence-free survival (RFS), and overall survival (OS). Results: Of the 477 (93%) evaluable tumors, 63 (13%) were scored as low. Low expression of 53BP1 was associated with worse outcomes for all endpoints studied, including 10-year IBRFS (76.8% vs. 90.5%; P=.01), OS (66.4% vs. 81.7%; P=.02), CSS (66.0% vs. 87.4%; P<.01), DMFS (55.9% vs. 87.0%; P<.01), and RFS (45.2% vs. 80.6%; P<.01). Multivariate analysis incorporating various clinico-pathologic markers and 53BP1 expression found that 53BP1 expression was again an independent predictor of all endpoints (IBRFS: P=.0254; OS: P=.0094; CSS: P=.0033; DMFS: P=.0006; RFS: P=.0002). Low 53BP1 expression was also found to correlate with triple-negative (TN) phenotype (P<.01). Furthermore, in subset analysis of all TN breast cancer, negative 53BP1 expression trended for lower IBRFS (72.3% vs. 93.9%; P=.0361) and was significant for worse DMFS (48.2% vs. 86.8%; P=.0035) and RFS (37.8% vs. 83.7%; P=.0014). Conclusion: Our data indicate that low 53BP1 expression is an independent prognostic indicator for local relapse among other endpoints in early-stage breast cancer and TN breast cancer patients treated with BCS+RT. These results should be verified in larger cohorts of patients to validate their

  15. Presença da Proteína p53 como Prognóstico de Recidiva/Progressão de Neoplasia Intra-epitelial Vulvar III p53 Protein Overexpression as a Prognostic Marker for Vulvar Intraepithelial Neoplasia III Recurrence/Progression

    Directory of Open Access Journals (Sweden)

    Isabel Cristina Chulvis do Val Guimarães

    2002-01-01

    Full Text Available Objetivo: avaliar o valor da presença da proteína p53 nos casos de recidiva/progressão da neoplasia intra-epitelial vulvar (VIN III. Métodos: foram selecionadas 20 pacientes com VIN III indiferenciada, seguidas semestralmente por período de até quatro anos, divididas em dois grupos: quatorze sem e seis com recidiva/progressão da lesão. Os casos de recidiva/progressão foram distribuídos da seguinte forma: em três pacientes a recidiva ocorreu uma única vez, em duas, houve dupla recorrência e apenas uma evoluiu para carcinoma escamoso. Em ambos os grupos foram avaliados o sítio vulvar acometido e a presença da proteína p53 com análise do padrão de marcação imunohistoquímica. Estudo semelhante foi realizado nos casos de recidiva/progressão além da análise do intervalo de tempo para o surgimento de recidiva/progressão. Resultados: observou-se recidiva da VIN III em 25% dos casos e, em 5%, progressão para carcinoma. O tempo médio de recidiva foi de 24,5 meses. A localização multifocal da lesão primária foi a mais freqüente (50% em ambos os grupos. Na maioria dos casos (87,5%, a recidiva/progressão ocorreu na mesma localização da lesão vulvar primária. A presença da proteína p53 mostrou-se positiva em 50% das lesões primárias de VIN III e em 75% dos casos de recidiva/progressão. Conclusões: a presença da proteína p53 parece desempenhar papel importante na gênese e na predição do curso clínico das VIN III. As recidivas/progressão das VIN III tendem a ocorrer na mesma área da doença inicial, sugerindo a presença de campo molecular alterado.Purpose: to evaluate p53 overexpression value in vulvar intraepithelial neoplasia (VIN III recurrence/progression. Methods: twenty patients with undifferentiated VIN III were selected and followed up every six months for four years and divided into two groups: fourteen without and six with recurrence/progression lesion. The recurrence/progression cases were

  16. Efficacy and Molecular Mechanisms of Differentiated Response to the Aurora and Angiogenic Kinase Inhibitor ENMD-2076 in Preclinical Models of p53-Mutated Triple-Negative Breast Cancer

    Directory of Open Access Journals (Sweden)

    Anastasia A. Ionkina

    2017-05-01

    Full Text Available PurposeTriple-negative breast cancer (TNBC is a subtype associated with poor prognosis and for which there are limited therapeutic options. The purpose of this study was to evaluate the efficacy of ENMD-2076 in p53-mutated TNBC patient-derived xenograft (PDX models and describe patterns of terminal cell fate in models demonstrating sensitivity, intrinsic resistance, and acquired resistance to ENMD-2076.Experimental designp53-mutated, TNBC PDX models were treated with ENMD-2076 and evaluated for mechanisms of sensitivity or resistance to treatment. Correlative tissue testing was performed on tumor tissue to assess for markers of proliferation, apoptosis, senescence, and pathways of resistance after treatment and at the time of acquired resistance.ResultsSensitivity to ENMD-2076 200 mg/kg daily was associated with induction of apoptosis while models exhibiting intrinsic or acquired resistance to treatment presented with a senescent phenotype. Response to ENMD-2076 was accompanied by an increase in p53 and p73 levels, even within the background of mutant p53. Treatment with ENMD-2076 resulted in a decrease in pAurA and an increase in pHH3. We observed a TNBC subtype switch from the luminal androgen receptor to the basal-like subtype at acquired resistance.ConclusionENMD-2076 has antitumor activity in preclinical models of p53-mutated TNBC. Increased levels of p53 and p73 correlated with sensitivity whereas senescence was associated with resistance to ENMD-2076. The novel finding of a TNBC subtype switch at time of acquired resistance may provide mechanistic insights into the biologic effects of selective pressure of anticancer treatments on TNBC. ENMD-2076 is currently being evaluated in a Phase 2 clinical trial in patients with metastatic, previously treated TNBC where these biologic correlates can be further explored.

  17. Molecular markers for diagnostic cytology of neoplasms in the head region of the pancreas: mutation of K-ras and overexpression of the p53 protein product

    NARCIS (Netherlands)

    van Es, J. M.; Polak, M. M.; van den Berg, F. M.; Ramsoekh, T. B.; Craanen, M. E.; Hruban, R. H.; Offerhaus, G. J.

    1995-01-01

    To determine the potential efficiency of molecular markers specific for neoplastic change--mutations of the K-ras oncogene and the p53 tumour suppressor gene--in diagnosing pancreatic carcinoma. Archival cytology samples obtained from 17 patients with established pancreatic carcinoma were assayed

  18. Hormonal control of p53 and chemoprevention

    International Nuclear Information System (INIS)

    Jerry, D Joseph; Minter, Lisa M; Becker, Klaus A; Blackburn, Anneke C

    2002-01-01

    Improvements in the detection and treatment of breast cancer have dramatically altered its clinical course and outcome. However, prevention of breast cancer remains an elusive goal. Parity, age of menarche, and age at menopause are major risk factors drawing attention to the important role of the endocrine system in determining the risk of breast cancer, while heritable breast cancer susceptibility syndromes have implicated tumor suppressor genes as important targets. Recent work demonstrating hormonal modulation of the p53 tumor suppressor pathway draws together these established determinants of risk to provide a model of developmental susceptibility to breast cancer. In this model, the mammary epithelium is rendered susceptible due to impaired p53 activity during specific periods of mammary gland development, but specific endocrine stimuli serve to activate p53 function and to mitigate this risk. The results focus attention on p53 as a molecular target for therapies to reduce the risk of breast cancer

  19. Roles of p53 and caspases in induction of apoptosis in MCF- 7 breast cancer cells treated with a methanolic extract of Nigella sativa seeds.

    Science.gov (United States)

    Alhazmi, Mohammed I; Hasan, Tarique N; Shafi, Gowhar; Al-Assaf, Abdullah H; Alfawaz, Mohammed A; Alshatwi, Ali A

    2014-01-01

    Nigella Sativa (NS) is an herb from the Ranunculaceae family that exhibits numerous medicinal properties and has been used as important constituent of many complementary and alternative medicines (CAMs). The ability of NS to kill cancer cells such as PC3, HeLa and hepatoma cells is well established. However, our understanding of the mode of death caused by NS remains nebulous. The objective of this study was to gain further insight into the mode and mechanism of death caused by NS in breast cancer MCF-7 cells. Human breast cancer cells (MCF-7) were treated with a methanolic extract of NS, and a dose- and time-dependent study was performed. The IC50 was calculated using a Cell Titer Blue® viability assay assay, and evidence for DNA fragmentation was obtained by fluorescence microscopy TUNEL assay. Gene expression was also profiled for a number of apoptosis-related genes (Caspase-3, -8, -9 and p53 genes) through qPCR. The IC50 of MCF-7 cells was 62.8 μL/mL. When MCF-7 cells were exposed to 50 μL/mL and 100 μL/mL NS for 24 h, 48 h and 72 h, microscopic examination (TUNEL assay) revealed a dose- and time-dependent increase in apoptosis. Similarly, the expression of the Caspase-3, -8, -9 and p53 genes increased significantly according to the dose and time. NS induced apoptosis in MCF-7 cells through both the p53 and caspase pathways. NS could potentially represent an alternative source of medicine for breast cancer therapy.

  20. Automated Quantitative Analysis of p53, Cyclin D1, Ki67 and pERK Expression in Breast Carcinoma Does Not Differ from Expert Pathologist Scoring and Correlates with Clinico-Pathological Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Cass, Jamaica D. [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Varma, Sonal [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Day, Andrew G. [Kingston General Hospital, Kingston K7L 2V7 (Canada); Sangrar, Waheed [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Rajput, Ashish B. [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Raptis, Leda H.; Squire, Jeremy [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Madarnas, Yolanda [Department of Oncology, Queen’s University, Kingston K7L 3N6 (Canada); SenGupta, Sandip K. [Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada); Elliott, Bruce E., E-mail: elliottb@queensu.ca [Division of Cancer Biology and Genetics, Cancer Research Institute, Queen’s University, Kingston K7L 3N6 (Canada); Department of Pathology and Molecular Medicine, Queen’s University, Kingston K7L 3N6 (Canada)

    2012-07-18

    There is critical need for improved biomarker assessment platforms which integrate traditional pathological parameters (TNM stage, grade and ER/PR/HER2 status) with molecular profiling, to better define prognostic subgroups or systemic treatment response. One roadblock is the lack of semi-quantitative methods which reliably measure biomarker expression. Our study assesses reliability of automated immunohistochemistry (IHC) scoring compared to manual scoring of five selected biomarkers in a tissue microarray (TMA) of 63 human breast cancer cases, and correlates these markers with clinico-pathological data. TMA slides were scanned into an Ariol Imaging System, and histologic (H) scores (% positive tumor area x staining intensity 0–3) were calculated using trained algorithms. H scores for all five biomarkers concurred with pathologists’ scores, based on Pearson correlation coefficients (0.80–0.90) for continuous data and Kappa statistics (0.55–0.92) for positive vs. negative stain. Using continuous data, significant association of pERK expression with absence of LVI (p = 0.005) and lymph node negativity (p = 0.002) was observed. p53 over-expression, characteristic of dysfunctional p53 in cancer, and Ki67 were associated with high grade (p = 0.032 and 0.0007, respectively). Cyclin D1 correlated inversely with ER/PR/HER2-ve (triple negative) tumors (p = 0.0002). Thus automated quantitation of immunostaining concurs with pathologists’ scoring, and provides meaningful associations with clinico-pathological data.

  1. Automated Quantitative Analysis of p53, Cyclin D1, Ki67 and pERK Expression in Breast Carcinoma Does Not Differ from Expert Pathologist Scoring and Correlates with Clinico-Pathological Characteristics

    International Nuclear Information System (INIS)

    Cass, Jamaica D.; Varma, Sonal; Day, Andrew G.; Sangrar, Waheed; Rajput, Ashish B.; Raptis, Leda H.; Squire, Jeremy; Madarnas, Yolanda; SenGupta, Sandip K.; Elliott, Bruce E.

    2012-01-01

    There is critical need for improved biomarker assessment platforms which integrate traditional pathological parameters (TNM stage, grade and ER/PR/HER2 status) with molecular profiling, to better define prognostic subgroups or systemic treatment response. One roadblock is the lack of semi-quantitative methods which reliably measure biomarker expression. Our study assesses reliability of automated immunohistochemistry (IHC) scoring compared to manual scoring of five selected biomarkers in a tissue microarray (TMA) of 63 human breast cancer cases, and correlates these markers with clinico-pathological data. TMA slides were scanned into an Ariol Imaging System, and histologic (H) scores (% positive tumor area x staining intensity 0–3) were calculated using trained algorithms. H scores for all five biomarkers concurred with pathologists’ scores, based on Pearson correlation coefficients (0.80–0.90) for continuous data and Kappa statistics (0.55–0.92) for positive vs. negative stain. Using continuous data, significant association of pERK expression with absence of LVI (p = 0.005) and lymph node negativity (p = 0.002) was observed. p53 over-expression, characteristic of dysfunctional p53 in cancer, and Ki67 were associated with high grade (p = 0.032 and 0.0007, respectively). Cyclin D1 correlated inversely with ER/PR/HER2-ve (triple negative) tumors (p = 0.0002). Thus automated quantitation of immunostaining concurs with pathologists’ scoring, and provides meaningful associations with clinico-pathological data

  2. p53 Represses the Oncogenic Sno-MiR-28 Derived from a SnoRNA.

    Directory of Open Access Journals (Sweden)

    Feng Yu

    Full Text Available p53 is a master tumour repressor that participates in vast regulatory networks, including feedback loops involving microRNAs (miRNAs that regulate p53 and that themselves are direct p53 transcriptional targets. We show here that a group of polycistronic miRNA-like non-coding RNAs derived from small nucleolar RNAs (sno-miRNAs are transcriptionally repressed by p53 through their host gene, SNHG1. The most abundant of these, sno-miR-28, directly targets the p53-stabilizing gene, TAF9B. Collectively, p53, SNHG1, sno-miR-28 and TAF9B form a regulatory loop which affects p53 stability and downstream p53-regulated pathways. In addition, SNHG1, SNORD28 and sno-miR-28 are all significantly upregulated in breast tumours and the overexpression of sno-miR-28 promotes breast epithelial cell proliferation. This research has broadened our knowledge of the crosstalk between small non-coding RNA pathways and roles of sno-miRNAs in p53 regulation.

  3. iASPP is over-expressed in human non-small cell lung cancer and regulates the proliferation of lung cancer cells through a p53 associated pathway

    International Nuclear Information System (INIS)

    Chen, Jinfeng; Xie, Fei; Zhang, Lijian; Jiang, Wen G

    2010-01-01

    iASPP is a key inhibitor of tumour suppressor p53 and is found to be up-regulated in certain malignant conditions. The present study investigated the expression of iASPP in clinical lung cancer, a leading cancer type in the world, and the biological impact of this molecule on lung cancer cells. iASPP protein levels in lung cancer tissues were evaluated using an immunohistochemical method. In vitro, iASPP gene expression was suppressed with a lentvirus-mediated shRNA method and the biological impact after knocking down iASSP on lung cancer cell lines was investigated in connection with the p53 expression status. We showed here that the expression of iASPP was significantly higher in lung cancer tissues compared with the adjacent normal tissues. iASPP shRNA treatment resulted in a down-regulation of iASPP in lung cancer cells. There was a subsequent reduction of cell proliferation of the two lung tumour cell lines A459 and 95D both of which had wild-type p53 expression. In contrast, reduction of iASPP in H1229 cells, a cell with little p53 expression, had no impact on its growth rate. iASPP regulates the proliferation and motility of lung cancer cells. This effect is intimately associated with the p53 pathway. Together with the pattern of the over-expression in clinical lung cancers, it is concluded that iASPP plays an pivotal role in the progression of lung cancer and is a potential target for lung cancer therapy

  4. Translational Control Protein 80 Stimulates IRES-Mediated Translation of p53 mRNA in Response to DNA Damage

    Directory of Open Access Journals (Sweden)

    Marie-Jo Halaby

    2015-01-01

    Full Text Available Synthesis of the p53 tumor suppressor increases following DNA damage. This increase and subsequent activation of p53 are essential for the protection of normal cells against tumorigenesis. We previously discovered an internal ribosome entry site (IRES that is located at the 5′-untranslated region (UTR of p53 mRNA and found that the IRES activity increases following DNA damage. However, the mechanism underlying IRES-mediated p53 translation in response to DNA damage is still poorly understood. In this study, we discovered that translational control protein 80 (TCP80 has increased binding to the p53 mRNA in vivo following DNA damage. Overexpression of TCP80 also leads to increased p53 IRES activity in response to DNA damage. TCP80 has increased association with RNA helicase A (RHA following DNA damage and overexpression of TCP80, along with RHA, leads to enhanced expression of p53. Moreover, we found that MCF-7 breast cancer cells with decreased expression of TCP80 and RHA exhibit defective p53 induction following DNA damage and diminished expression of its downstream target PUMA, a proapoptotic protein. Taken together, our discovery of the function of TCP80 and RHA in regulating p53 IRES and p53 induction following DNA damage provides a better understanding of the mechanisms that regulate IRES-mediated p53 translation in response to genotoxic stress.

  5. Cytotoxicity and Proapoptotic Effects of Allium atroviolaceum Flower Extract by Modulating Cell Cycle Arrest and Caspase-Dependent and p53-Independent Pathway in Breast Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Somayeh Khazaei

    2017-01-01

    Full Text Available Breast cancer is the second leading cause of cancer death among women and despite significant advances in therapy, it remains a critical health problem worldwide. Allium atroviolaceum is an herbaceous plant, with limited information about the therapeutic capability. We aimed to study the anticancer effect of flower extract and the mechanisms of action in MCF-7 and MDA-MB-231. The extract inhibits the proliferation of the cells in a time- and dose-dependent manner. The underlying mechanism involved the stimulation of S and G2/M phase arrest in MCF-7 and S phase arrest in MDA-MB-231 associated with decreased level of Cdk1, in a p53-independent pathway. Furthermore, the extract induces apoptosis in both cell lines, as indicated by the percentage of sub-G0 population, the morphological changes observed by phase contrast and fluorescent microscopy, and increase in Annexin-V-positive cells. The apoptosis induction was related to downregulation of Bcl-2 and also likely to be caspase-dependent. Moreover, the combination of the extract and tamoxifen exhibits synergistic effect, suggesting that it can complement current chemotherapy. LC-MS analysis displayed 17 major compounds in the extract which might be responsible for the observed effects. Overall, this study demonstrates the potential applications of Allium atroviolaceum extract as an anticancer drug for breast cancer treatment.

  6. N-methylpurine DNA glycosylase inhibits p53-mediated cell cycle arrest and coordinates with p53 to determine sensitivity to alkylating agents.

    Science.gov (United States)

    Song, Shanshan; Xing, Guichun; Yuan, Lin; Wang, Jian; Wang, Shan; Yin, Yuxin; Tian, Chunyan; He, Fuchu; Zhang, Lingqiang

    2012-08-01

    Alkylating agents induce genome-wide base damage, which is repaired mainly by N-methylpurine DNA glycosylase (MPG). An elevated expression of MPG in certain types of tumor cells confers higher sensitivity to alkylation agents because MPG-induced apurinic/apyrimidic (AP) sites trigger more strand breaks. However, the determinant of drug sensitivity or insensitivity still remains unclear. Here, we report that the p53 status coordinates with MPG to play a pivotal role in such process. MPG expression is positive in breast, lung and colon cancers (38.7%, 43.4% and 25.3%, respectively) but negative in all adjacent normal tissues. MPG directly binds to the tumor suppressor p53 and represses p53 activity in unstressed cells. The overexpression of MPG reduced, whereas depletion of MPG increased, the expression levels of pro-arrest gene downstream of p53 including p21, 14-3-3σ and Gadd45 but not proapoptotic ones. The N-terminal region of MPG was specifically required for the interaction with the DNA binding domain of p53. Upon DNA alkylation stress, in p53 wild-type tumor cells, p53 dissociated from MPG and induced cell growth arrest. Then, AP sites were repaired efficiently, which led to insensitivity to alkylating agents. By contrast, in p53-mutated cells, the AP sites were repaired with low efficacy. To our knowledge, this is the first direct evidence to show that a DNA repair enzyme functions as a selective regulator of p53, and these findings provide new insights into the functional linkage between MPG and p53 in cancer therapy.

  7. Polycomb Group Protein PHF1 Regulates p53-dependent Cell Growth Arrest and Apoptosis*

    Science.gov (United States)

    Yang, Yang; Wang, Chenji; Zhang, Pingzhao; Gao, Kun; Wang, Dejie; Yu, Hongxiu; Zhang, Ting; Jiang, Sirui; Hexige, Saiyin; Hong, Zehui; Yasui, Akira; Liu, Jun O.; Huang, Haojie; Yu, Long

    2013-01-01

    Polycomb group protein PHF1 is well known as a component of a novel EED-EZH2·Polycomb repressive complex 2 complex and plays important roles in H3K27 methylation and Hox gene silencing. PHF1 is also involved in the response to DNA double-strand breaks in human cells, promotes nonhomologous end-joining processes through interaction with Ku70/Ku80. Here, we identified another function of PHF1 as a potential p53 pathway activator in a pathway screen using luminescence reporter assay. Subsequent studies showed PHF1 directly interacts with p53 proteins both in vivo and in vitro and co-localized in nucleus. PHF1 binds to the C-terminal regulatory domain of p53. Overexpression of PHF1 elevated p53 protein level and prolonged its turnover. Knockdown of PHF1 reduced p53 protein level and its target gene expression both in normal state and DNA damage response. Mechanically, PHF1 protects p53 proteins from MDM2-mediated ubiquitination and degradation. Furthermore, we showed that PHF1 regulates cell growth arrest and etoposide-induced apoptosis in a p53-dependent manner. Finally, PHF1 expression was significantly down-regulated in human breast cancer samples. Taken together, we establish PHF1 as a novel positive regulator of the p53 pathway. These data shed light on the potential roles of PHF1 in tumorigenesis and/or tumor progression. PMID:23150668

  8. OTUD5 regulates p53 stability by deubiquitinating p53.

    Directory of Open Access Journals (Sweden)

    Judong Luo

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

  9. Changes in the ER, PgR, HER2, p53 and Ki-67 biological markers between primary and recurrent breast cancer: discordance rates and prognosis

    Directory of Open Access Journals (Sweden)

    Tashima Rumiko

    2011-10-01

    Full Text Available Abstract Background In breast cancer, ER/PgR, HER2, and Ki-67 are important biological markers for predicting prognosis and making effective treatment decisions. In addition, changes in markers due to relapse are also clinically experienced; however, the frequency and clinical significance are still not fully understood. Thus, changes in markers and their correlations with prognosis were investigated. Patients and Methods Out of the patients with relapse from 1997 to March 2011, there were 97 consecutive patients from whom the lesion was resected and evaluated by immunostaining. The biopsy sites were chest wall, lymph node, ipsilateral breast tumor recurrence, lungs, bones, ovaries and brain. The markers sought were ER, PgR, HER2, p53 and Ki-67. Results The hormone receptor positive rate from the primary tumor to recurrence decreased from 63.9% to 57.7% and from 56.7% to 43.3% for ER and PgR, respectively. Changes in the positive/negative evaluation were seen at the rate of 10.3% and 25.8% for ER and PgR, respectively. The Ki-67 index increased significantly from a mean of 29.1% at primary tumor to 36.3% at relapse. When divided into 2 groups ( Conclusion Estrogen receptor and PgR decreased while Ki-67 increased due to relapse; however, the rate of change was high for PgR and Ki-67. Change in the subtypes was seen in 25%. In addition, PgR at relapse and Ki-67 at primary tumor were significant factors for post-relapse prognosis while PgR becoming negative was a poor prognostic factor. These findings are important for making effective treatment decisions.

  10. Phospho-aspirin (MDC-22) inhibits breast cancer in preclinical animal models: an effect mediated by EGFR inhibition, p53 acetylation and oxidative stress

    International Nuclear Information System (INIS)

    Huang, Liqun; Wong, Chi C; Mackenzie, Gerardo G; Sun, Yu; Cheng, Ka Wing; Vrankova, Kvetoslava; Alston, Ninche; Ouyang, Nengtai; Rigas, Basil

    2014-01-01

    The anticancer properties of aspirin are restricted by its gastrointestinal toxicity and its limited efficacy. Therefore, we synthesized phospho-aspirin (PA-2; MDC-22), a novel derivative of aspirin, and evaluated its chemotherapeutic and chemopreventive efficacy in preclinical models of triple negative breast cancer (TNBC). Efficacy of PA-2 was evaluated in human breast cancer cells in vitro, and in orthotopic and subcutaneous TNBC xenografts in nude mice. Mechanistic studies were also carried out to elucidate the mechanism of action of PA-2. PA-2 inhibited the growth of TNBC cells in vitro more potently than aspirin. Treatment of established subcutaneous TNBC xenografts (MDA-MB-231 and BT-20) with PA-2 induced a strong growth inhibitory effect, resulting in tumor stasis (79% and 90% inhibition, respectively). PA-2, but not aspirin, significantly prevented the development of orthotopic MDA-MB-231 xenografts (62% inhibition). Mechanistically, PA-2: 1) inhibited the activation of epidermal growth factor receptor (EGFR) and suppressed its downstream signaling cascades, including PI3K/AKT/mTOR and STAT3; 2) induced acetylation of p53 at multiple lysine residues and enhanced its DNA binding activity, leading to cell cycle arrest; and 3) induced oxidative stress by suppressing the thioredoxin system, consequently inhibiting the activation of the redox sensitive transcription factor NF-κB. These molecular alterations were observed in vitro and in vivo, demonstrating their relevance to the anticancer effect of PA-2. Our findings demonstrate that PA-2 possesses potent chemotherapeutic efficacy against TNBC, and is also effective in its chemoprevention, warranting further evaluation as an anticancer agent

  11. Inhibition of p53 acetylation by INHAT subunit SET/TAF-Iβ represses p53 activity.

    Science.gov (United States)

    Kim, Ji-Young; Lee, Kyu-Sun; Seol, Jin-Ee; Yu, Kweon; Chakravarti, Debabrata; Seo, Sang-Beom

    2012-01-01

    The tumor suppressor p53 responds to a wide variety of cellular stress signals. Among potential regulatory pathways, post-translational modifications such as acetylation by CBP/p300 and PCAF have been suggested for modulation of p53 activity. However, exactly how p53 acetylation is modulated remains poorly understood. Here, we found that SET/TAF-Iβ inhibited p300- and PCAF-mediated p53 acetylation in an INHAT (inhibitor of histone acetyltransferase) domain-dependent manner. SET/TAF-Iβ interacted with p53 and repressed transcription of p53 target genes. Consequently, SET/TAF-Iβ blocked both p53-mediated cell cycle arrest and apoptosis in response to cellular stress. Using different apoptosis analyses, including FACS, TUNEL and BrdU incorporation assays, we also found that SET/TAF-Iβ induced cellular proliferation via inhibition of p53 acetylation. Furthermore, we observed that apoptotic Drosophila eye phenotype induced by either dp53 overexpression or UV irradiation was rescued by expression of dSet. Inhibition of dp53 acetylation by dSet was observed in both cases. Our findings provide new insights into the regulation of stress-induced p53 activation by HAT-inhibiting histone chaperone SET/TAF-Iβ.

  12. Brca1/p53 deficient mouse breast tumor hemodynamics during hyperoxic respiratory challenge monitored by a novel wide-field functional imaging (WiFI) system

    Science.gov (United States)

    Moy, Austin; Kim, Jae G.; Lee, Eva Y. H. P.; Tromberg, Bruce; Cerussi, Albert; Choi, Bernard

    2009-02-01

    Current imaging modalities allow precise visualization of tumors but do not enable quantitative characterization of the tumor metabolic state. Such quantitative information would enhance our understanding of tumor progression and response to treatment, and to our overall understanding of tumor biology. To address this problem, we have developed a wide-field functional imaging (WiFI) instrument which combines two optical imaging modalities, spatially modulated imaging (MI) and laser speckle imaging (LSI). Our current WiFI imaging protocol consists of multispectral imaging in the near infrared (650-980 nm) spectrum, over a wide (7 cm × 5 cm) field of view. Using MI, the spatially-resolved reflectance of sinusoidal patterns projected onto the tissue is assessed, and optical properties of the tissue are estimated using a Monte Carlo model. From the spatial maps of local absorption and reduced scattering coefficients, tissue composition information is extracted in the form of oxy-, deoxy-, and total hemoglobin concentrations, and percentage of lipid and water. Using LSI, the reflectance of a 785 nm laser speckle pattern on the tissue is acquired and analyzed to compute maps of blood perfusion in the tissue. Tissue metabolism state is estimated from the values of blood perfusion, volume and oxygenation state. We currently are employing the WiFI instrument to study tumor development in a BRCA1/p53 deficient mice breast tumor model. The animals are monitored with WiFI during hyperoxic respiratory challenge. At present, four tumors have been measured with WiFI, and preliminary data suggest that tumor metabolic changes during hyperoxic respiratory challenge can be determined.

  13. S100A4 interacts with p53 in the nucleus and promotes p53 degradation.

    Science.gov (United States)

    Orre, L M; Panizza, E; Kaminskyy, V O; Vernet, E; Gräslund, T; Zhivotovsky, B; Lehtiö, J

    2013-12-05

    S100A4 is a small calcium-binding protein that is commonly overexpressed in a range of different tumor types, and it is widely accepted that S100A4 has an important role in the process of cancer metastasis. In vitro binding assays has shown that S100A4 interacts with the tumor suppressor protein p53, indicating that S100A4 may have additional roles in tumor development. In the present study, we show that endogenous S100A4 and p53 interact in complex samples, and that the interaction increases after inhibition of MDM2-dependent p53 degradation using Nutlin-3A. Further, using proximity ligation assay, we show that the interaction takes place in the cell nucleus. S100A4 knockdown experiments in two p53 wild-type cell lines, A549 and HeLa, resulted in stabilization of p53 protein, indicating that S100A4 is promoting p53 degradation. Finally, we demonstrate that S100A4 knockdown leads to p53-dependent cell cycle arrest and increased cisplatin-induced apoptosis. Thus, our data add a new layer to the oncogenic properties of S100A4 through its inhibition of p53-dependent processes.

  14. Overexpression of BLCAP induces S phase arrest and apoptosis independent of p53 and NF-kappa B in human tongue carcinoma - BLCAP overexpression induces S phase arrest and apoptosis

    NARCIS (Netherlands)

    Yao, Jun; Duan, Li; Fan, Mingwen; Yuan, Jianhuan; Wu, Xinxing

    Bladder cancer-associated protein gene (BLCAP) is a novel candidate tumor suppressor gene identified from the human bladder carcinoma. Our previous studies have shown that BLCAP overexpression could inhibit cell growth by inducing apoptosis in HeLa cells [Zuo Z, Zhao M, Liu J, Gao G, Wu X: Tumor

  15. 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.

    Directory of Open Access Journals (Sweden)

    Eszter Lakatos

    Full Text Available 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.

  16. 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.

  17. Chemical Variations on the p53 Reactivation Theme

    Directory of Open Access Journals (Sweden)

    Carlos J. A. Ribeiro

    2016-05-01

    Full Text Available Among the tumor suppressor genes, p53 is one of the most studied. It is widely regarded as the “guardian of the genome”, playing a major role in carcinogenesis. In fact, direct inactivation of the TP53 gene occurs in more than 50% of malignancies, and in tumors that retain wild-type p53 status, its function is usually inactivated by overexpression of negative regulators (e.g., MDM2 and MDMX. Hence, restoring p53 function in cancer cells represents a valuable anticancer approach. In this review, we will present an updated overview of the most relevant small molecules developed to restore p53 function in cancer cells through inhibition of the p53-MDMs interaction, or direct targeting of wild-type p53 or mutated p53. In addition, optimization approaches used for the development of small molecules that have entered clinical trials will be presented.

  18. Screening of medicinal plant phytochemicals as natural antagonists of p53-MDM2 interaction to reactivate p53 functioning.

    Science.gov (United States)

    Riaz, Muhammad; Ashfaq, Usman A; Qasim, Muhammad; Yasmeen, Erum; Ul Qamar, Muhammad T; Anwar, Farooq

    2017-10-01

    In most types of cancer, overexpression of murine double minute 2 (MDM2) often leads to inactivation of p53. The crystal structure of MDM2, with a 109-residue amino-terminal domain, reveals that MDM2 has a core hydrophobic region to which p53 binds as an amphipathic α helix. The interface depends on the steric complementarity between MDM2 and the hydrophobic region of p53. Especially, on p53's triad, amino acids Phe19, Trp23 and Leu26 bind to the MDM2 core. Results from studies suggest that the structural motif of both p53 and MDM2 can be attributed to similarities in the amphipathic α helix. Thus, in the current investigation it is hypothesized that the similarity in the structural motif might be the cause of p53 inactivation by MDM2. Hence, molecular docking and phytochemical screening approaches are appraised to inhibit the hydrophobic cleft of MDM2 and to stop p53-MDM2 interaction, resulting in reactivation of p53 activity. For this purpose, a library of 2295 phytochemicals were screened against p53-MDM2 to find potential candidates. Of these, four phytochemicals including epigallocatechin gallate, alvaradoin M, alvaradoin E and nordihydroguaiaretic acid were found to be potential inhibitors of p53-MDM2 interaction. The screened phytochemicals, derived from natural extracts, may have negligible side effects and can be explored as potent antagonists of p53-MDM2 interactions, resulting in reactivation of the normal transcription of p53.

  19. TGFbeta1 (Leu10Pro), p53 (Arg72Pro) can predict for increased risk for breast cancer in south Indian women and TGFbeta1 Pro (Leu10Pro) allele predicts response to neo-adjuvant chemo-radiotherapy.

    Science.gov (United States)

    Rajkumar, Thangarajan; Samson, Mani; Rama, Ranganathan; Sridevi, Veluswami; Mahji, Urmila; Swaminathan, Rajaraman; Nancy, Nirmala K

    2008-11-01

    The breast cancer incidence has been increasing in the south Indian women. A case (n=250)-control (n=500) study was undertaken to investigate the role of Single Nucleotide Polymorphisms (SNP's) in GSTM1 (Present/Null); GSTP1 (Ile105Val), p53 (Arg72Pro), TGFbeta1 (Leu10Pro), c-erbB2 (Ile655Val), and GSTT1 (Null/Present) in breast cancer. In addition, the value of the SNP's in predicting primary tumor's pathologic response following neo-adjuvant chemo-radiotherapy was assessed. Genotyping was done using PCR (GSTM1, GSTT1), Taqman Allelic discrimination assay (GSTP1, c-erbB2) and PCR-CTPP (p53 and TGFbeta1). None of the gene SNP's studied were associated with a statistically significant increased risk for the breast cancer. However, combined analysis of the SNP's showed that p53 (Arg/Arg and Arg/Pro) with TGFbeta1 (Pro/Pro and Leu/Pro) were associated with greater than 2 fold increased risk for breast cancer in Univariate (P=0.01) and Multivariate (P=0.003) analysis. There was no statistically significant association for the GST family members with the breast cancer risk. TGFbeta1 (Pro/Pro) allele was found to predict complete pathologic response in the primary tumour following neo-adjuvant chemo-radiotherapy (OR=6.53 and 10.53 in Univariate and Multivariate analysis respectively) (P=0.004) and was independent of stage. This study suggests that SNP's can help predict breast cancer risk in south Indian women and that TGFbeta1 (Pro/Pro) allele is associated with a better pCR in the primary tumour.

  20. Interactions between Exosomes from Breast Cancer Cells and Primary Mammary Epithelial Cells Leads to Generation of Reactive Oxygen Species Which Induce DNA Damage Response, Stabilization of p53 and Autophagy in Epithelial Cells

    Science.gov (United States)

    Dutta, Sujoy; Warshall, Case; Bandyopadhyay, Chirosree; Dutta, Dipanjan; Chandran, Bala

    2014-01-01

    Exosomes are nanovesicles originating from multivesicular bodies and are released by all cell types. They contain proteins, lipids, microRNAs, mRNAs and DNA fragments, which act as mediators of intercellular communications by inducing phenotypic changes in recipient cells. Tumor-derived exosomes have been shown to play critical roles in different stages of tumor development and metastasis of almost all types of cancer. One of the ways by which exosomes affect tumorigenesis is to manipulate the tumor microenvironments to create tumor permissive “niches”. Whether breast cancer cell secreted exosomes manipulate epithelial cells of the mammary duct to facilitate tumor development is not known. To address whether and how breast cancer cell secreted exosomes manipulate ductal epithelial cells we studied the interactions between exosomes isolated from conditioned media of 3 different breast cancer cell lines (MDA-MB-231, T47DA18 and MCF7), representing three different types of breast carcinomas, and normal human primary mammary epithelial cells (HMECs). Our studies show that exosomes released by breast cancer cell lines are taken up by HMECs, resulting in the induction of reactive oxygen species (ROS) and autophagy. Inhibition of ROS by N-acetyl-L-cysteine (NAC) led to abrogation of autophagy. HMEC-exosome interactions also induced the phosphorylation of ATM, H2AX and Chk1 indicating the induction of DNA damage repair (DDR) responses. Under these conditions, phosphorylation of p53 at serine 15 was also observed. Both DDR responses and phosphorylation of p53 induced by HMEC-exosome interactions were also inhibited by NAC. Furthermore, exosome induced autophagic HMECs were found to release breast cancer cell growth promoting factors. Taken together, our results suggest novel mechanisms by which breast cancer cell secreted exosomes manipulate HMECs to create a tumor permissive microenvironment. PMID:24831807

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

    Directory of Open Access Journals (Sweden)

    Ivan Raimondi

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

  2. The p53-MDM2 network: from oscillations to apoptosis

    Indian Academy of Sciences (India)

    PRAKASH KUMAR

    Apoptosis; cancer; cell cycle; MDM2 overexpression; tumour suppressor .... model of the p53-MDM2 negative feedback loop included an .... MDM2 overexpression, when subjected to nutlin-3 treatment. Some aspects of the model are similar to those ... A family of proteases termed caspases .... Implications for therapy; Proc.

  3. Ziyuglycoside I Inhibits the Proliferation of MDA-MB-231 Breast Carcinoma Cells through Inducing p53-Mediated G2/M Cell Cycle Arrest and Intrinsic/Extrinsic Apoptosis.

    Science.gov (United States)

    Zhu, Xue; Wang, Ke; Zhang, Kai; Zhang, Ting; Yin, Yongxiang; Xu, Fei

    2016-11-22

    Due to the aggressive clinical behavior, poor outcome, and lack of effective specific targeted therapies, triple-negative breast cancer (TNBC) has currently been recognized as one of the most malignant types of tumors. In the present study, we investigated the cytotoxic effect of ziyuglycoside I, one of the major components extracted from Chinese anti-tumor herbal Radix Sanguisorbae , on the TNBC cell line MDA-MB-231. The underlying molecular mechanism of the cytotoxic effect ziyuglycoside I on MDA-MB-231 cells was investigated with cell viability assay, flow cytometric analysis and Western blot. Compared to normal mammary gland Hs 578Bst cells, treatment of ziyuglycoside I resulted in a significant growth inhibitory effect on MDA-MB-231 cells. Ziyuglycoside I induced the G2/M phase arrest and apoptosis of MDA-MB-231 cells in a dose-dependent manner. These effects were found to be partially mediated through the up-regulation of p53 and p21 WAF1 , elevated Bax/Bcl-2 ratio, and the activation of both intrinsic (mitochondrial-initiated) and extrinsic (Fas/FasL-initiated) apoptotic pathways. Furthermore, the p53 specific siRNA attenuated these effects. Our study suggested that ziyuglycoside I-triggered MDA-MB-231 cell cycle arrest and apoptosis were probably mediated by p53. This suggests that ziyuglycoside I might be a potential drug candidate for treating TNBC.

  4. TRIM65 negatively regulates p53 through ubiquitination

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yang [Department of Respiration, The First Hospital of Jilin University, Changchun 130021 (China); Ma, Chengyuan [Department of Neurosurgery, The First Hospital of Jilin University, Changchun 130021 (China); Zhou, Tong [Department of Endocrinology, The First Hospital of Jilin University, Changchun 130021 (China); Liu, Ying [Department of Respiration, The First Hospital of Jilin University, Changchun 130021 (China); Sun, Luyao [Department of Infectious Diseases, The First Hospital of Jilin University, Changchun 130021 (China); Yu, Zhenxiang, E-mail: zhenxiangyu2015@gmail.com [Department of Respiration, The First Hospital of Jilin University, Changchun 130021 (China)

    2016-04-22

    Tripartite-motif protein family member 65 (TRIM65) is an important protein involved in white matter lesion. However, the role of TRIM65 in human cancer remains less understood. Through the Cancer Genome Atlas (TCGA) gene alteration database, we found that TRIM65 is upregulated in a significant portion of non-small cell lung carcinoma (NSCLC) patients. Our cell growth assay revealed that TRIM65 overexpression promotes cell proliferation, while knockdown of TRIM65 displays opposite effect. Mechanistically, TRIM65 binds to p53, one of the most critical tumor suppressors, and serves as an E3 ligase toward p53. Consequently, TRIM65 inactivates p53 through facilitating p53 poly-ubiquitination and proteasome-mediated degradation. Notably, chemotherapeutic reagent cisplatin induction of p53 is markedly attenuated in response to ectopic expression of TRIM65. Cell growth inhibition by TRIM65 knockdown is more significant in p53 positive H460 than p53 negative H1299 cells, and knockdown of p53 in H460 cells also shows compromised cell growth inhibition by TRIM65 knockdown, indicating that p53 is required, at least in part, for TRIM65 function. Our findings demonstrate TRIM65 as a potential oncogenic protein, highly likely through p53 inactivation, and provide insight into development of novel approaches targeting TRIM65 for NSCLC treatment, and also overcoming chemotherapy resistance. - Highlights: • TRIM65 expression is elevated in NSCLC. • TRIM65 inactivates p53 through mediating p53 ubiquitination and degradation. • TRIM65 attenuates the response of NSCLC cells to cisplatin.

  5. Analysis of p53- immunoreactivity in astrocytic brain tumors

    Directory of Open Access Journals (Sweden)

    Shinkarenko T.V.

    2016-12-01

    Full Text Available P53 is an antioncogene with the frequently occured mutations in human tumor cells, leading to corresponding protein overexpression which can be detected by immunohistochemistry. Researches dedicated to the investigation of possibilities of using this technique gave controversial results. The authors investigated features of p53 protein expression in astrocytic brain tumors with different degrees of malignancy. Analyzed the relationship of the expression level of p53 by tumor cells with clinical parameters and Ki-67 proliferation index (PI as well. Tissues were collected from 52 cases with diagnosed astrocytic brain tumors. The sections were immunohistochemically stained with p53 and Ki-67. For each marker, 1000 tumor cells were counted and the ratio of positive tumor cells was calculated using software package ImageJ 1,47v. In normal brain tissue p53- expression was not identified. p53-immunoreactive tumor cells were detected in 25% (1/4 pilocytic astrocytomas, 33.3% (2/6 of diffuse astrocytomas, 53.8% (7/13 anaplastic astrocytomas, 58.6% (17/29 glioblastomas. A high proportion of p53-immunoreactive cells (> 30% was observed only in glioblastomas. The level of p53-imunoreactivity was not related to the age, gender and Grade WHO (p> 0,05. Spearman correlation coefficient between the relative quantity of ki-67- and p53-immunoreactive nuclei showed weak direct correlation (0.023, but the one was not statistically significant (p> 0,05. The level of p53-imunoreactivity is not dependent from age and sex of patients, Grade (WHO and proliferative activity (p>0,05 but the high level of p53-immunoreactive cells (>30% is found in glioblastoma specimens only, that may be due to the accumulation of mutations in DNA of tumor cells. There is insignificant weak relationship between relative quantities of ki-67- and p53-immunoreactive tumor cells (p>0,05.

  6. Indicadores de Prognóstico em Câncer de Mama com Axila Negativa: Receptor de Estrógeno e Expressão de P53 e de c-erbB-2 Prognostic Indicators In Lymph Node-Negative Breast Cancer: Estrogen Receptor and P53 and c-erbB-2 Protein Expression

    Directory of Open Access Journals (Sweden)

    Adriana Harter Teixeira Bolaséll

    2000-08-01

    dos linfonodos axilares tem pior prognóstico, em relação ao intervalo livre de doença, quando apresentam associação de tumor pouco diferenciado com RE negativo, p53 positivo e c-erbB-2 positivo.Purpose: to evaluate the prognostic value of estrogen receptor and p53 and c-erbB-2 proteins in lymph node-negative breast cancer. Methods: an immunohistochemical study was made in paraffin-embedded tissues from the file of the Instituto de Pesquisas Cito-Oncológicas of the Fundação Faculdade Federal de Ciências Médicas de Porto Alegre of fifty cases of postmenopausal women, who were treated at the Irmandade da Santa Casa de Misericórdia de Porto Alegre and at the Santa Rita Hospital from 1990 to 1994. For statistical analysis c² with Yates correction, as well as exact Fisher tests were used and Kaplan Meier curves compared with log-rank test. The mean follow-up of the patients was 3.6 years (3.1-4.5. Of the 50 cases, 14 showed recurrence during the period of follow-up. Results: the mean age was 61 years (46-78. Modified radical mastectomy was performed in 35 patients (70% and 15 (30% were submitted to lumpectomy/axillary dissection and postoperative radiation therapy. Fifty percent of the patients who showed recurrence did it in the first three years after the diagnosis. The mean size of the tumor was 2.8 cm (1.98-3.13 and the most frequent histological type was invasive ductal carcinoma of no special type (92%, according to the Bloom and Richardson graduation, 3 being stage I (6.6%, 35 stage II (76% and 8 stage III (17.4%. In the tumors with recurrence, there was no grade I, 9 stage II (25.7% and 3 stage III (37.5%. In relation to the prognosis, the disease-free interval was less when there was association of a poorly differentiated tumor with negative estrogen receptor (p = 0.006, positive p53 (p = 0.006 and positive c-erbB-2 (p = 0.001. Conclusion: postmenopausal women with lymph node-negative breast cancer showed worse prognosis in relation to disease

  7. INGN 201: Ad-p53, Ad5CMV-p53, Adenoviral p53, INGN 101, p53 gene therapy--Introgen, RPR/INGN 201.

    Science.gov (United States)

    2003-01-01

    undergoing phase I trials for the potential treatment of lung, breast, ovarian, bladder, liver and brain cancers. Introgen and Aventis Pharma had signed a Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute (NCI). NCI will sponsor clinical trials to evaluate and develop RPR/INGN 201 as a potential anticancer agent for these cancer indications. The trials conducted under a NCI-sponsored IND will evaluate RPR/INGN 201 alone and in combination with other anticancer agents. This agreement was originally signed by Rhône-Poulenc Rorer's Gencell. Introgen has completed three phase I clinical trials with INGN 201 in patients with bronchioalveolar cell lung carcinoma, ovarian cancer and recurrent glioblastomas, respectively. Intratumoural injection of RPR/INGN 201 in patients with recurrent glioblastomas was well tolerated and resulted in expression of the p53 protein. Direct administration of RPR/INGN 201 to the lower airways of patients with bronchioalveolar cell lung carcinoma resulted in symptomatic improvement and improved lung function in some patients. In February 2003, Introgen announced that the US Patent and Trademark Office has issued to The Board of Regents of The University of Texas System, patent No. 6,511,847 entitled "Recombinant p53 Adenovirus Methods and Compositions". Introgen Therapeutics is the exclusive licensee of this patent. The patent covers any adenoviral DNA molecules that encode the p53 gene positioned under the control of a promoter. Such a DNA molecule forms the genetic core of Introgen's ADVEXIN cancer therapy. Introgen's ADVEXIN therapy is now covered by up to ten separate US patents relevant to the product including compositions, therapeutic methods of administering the product in virtually any form, alone and in conjunction with the most widely used chemotherapeutic and radiation treatments, as well as its production. Introgen has a number of US patents that relate to the clinical use of ADVEXIN in cancer as

  8. The Transcriptional Landscape of p53 Signalling Pathway

    Directory of Open Access Journals (Sweden)

    Chizu Tanikawa

    2017-06-01

    Full Text Available Although recent cancer genomics studies have identified a large number of genes that were mutated in human cancers, p53 remains as the most frequently mutated gene. To further elucidate the p53-signalling network, we performed transcriptome analysis on 24 tissues in p53+/+ or p53−/− mice after whole-body X-ray irradiation. Here we found transactivation of a total of 3551 genes in one or more of the 24 tissues only in p53+/+ mice, while 2576 genes were downregulated. p53 mRNA expression level in each tissue was significantly associated with the number of genes upregulated by irradiation. Annotation using TCGA (The Cancer Genome Atlas database revealed that p53 negatively regulated mRNA expression of several cancer therapeutic targets or pathways such as BTK, SYK, and CTLA4 in breast cancer tissues. In addition, stomach exhibited the induction of Krt6, Krt16, and Krt17 as well as loricrin, an epidermal differentiation marker, after the X-ray irradiation only in p53+/+ mice, implying a mechanism to protect damaged tissues by rapid induction of differentiation. Our comprehensive transcriptome analysis elucidated tissue specific roles of p53 and its signalling networks in DNA-damage response that will enhance our understanding of cancer biology.

  9. Induction of PTEN-p53 crosstalk in mammary epithelial cells: A novel mechanism of breast cancer prevention by the dietary factor genistein

    Science.gov (United States)

    Consumption of soy foods either at an early age or for lifetime has been associated with reduced risk for developing breast cancer in humans and in animal models. However, this association continues to be controversial, and the precise mechanisms for protection remain elusive. Among the soy products...

  10. Expression of p53 and p21 in primary glioblastomas

    International Nuclear Information System (INIS)

    Gross, M.W.; Nashwan, K.; Engenhart-Cabillic, R.; Kraus, A.; Mennel, H.D.; Schlegel, J.

    2005-01-01

    Background and purpose: primary glioblastomas (GBMs) are highly radioresistant, and in contrast to secondary GBMs, they bear wild-type (wt) p53 protein, which is stabilized in a proportion of these tumors. Therefore, it was investigated in vivo whether p53 expression has prognostic value in patients undergoing radiochemotherapy. Additionally, the authors tried to identify, in vitro, subgroups of primary GBM with different susceptibilities to irradiation, on the basis of their p53 and p21 responses to ionizing radiation. Material and methods: tumor tissue samples from 31 patients suffering from primary GBM undergoing a combined radiochemotherapy with topotecan were investigated. The percentage of cells expressing p53 protein was determined immunohistochemically. Additionally, primary cultures from eleven primary GBMs were established and investigated. p53 and p21 expressions were evaluated before irradiation with 10 Gy and at 2 and 8 h after irradiation. p53 protein expression was measured by western analysis and p21 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). Results: the percentage of p53-positive cells within the tumor specimens obtained from the 31 patients ranged from 0% to 28%, the median value being 4.3%. No significant correlation with disease-free survival or overall survival was found. In vitro, p53 protein was detected in seven of eleven cultures from primary GBM. After irradiation a decrease in p53 protein expression was seen in six of the seven p53-positive cultures. Half of the cultures (two of four) without basal p53 expression showed an increase in p53 expression after irradiation. Basal overexpression of p21 was detected in six of the eleven cultures; in four out of six irradiation led to a decrease in p21 expression. In all cell lines (five of eleven) initially showing absent p21 expression, irradiation induced p21 expression. Despite these responses, G1 arrest was not detectable in any of the GBM cultures

  11. A surrogate p53 reporter in Drosophila reveals the interaction of eIF4E and p53

    International Nuclear Information System (INIS)

    Corujo, G.; Campagno, R.; Rivera Pomar, R.; Ferrero, P.; Lu, W.J.

    2011-01-01

    eIF4E promotes translation upon binding the mRNA 5'cap and it is required for cell proliferation. p53 is a proapoptotic protein which is activated in response to DNA damage. There is evidence that suggests that eIF4E and p53 are connected in a mechanism that regulates their function. We propose a model for that such a mechanism to explain the equilibrium between apoptosis and cell proliferation. Our data shows a correlation between the overexpression of eIF4E and the suppression of apoptosis triggered by the overexpression of p53 in Drosophila imaginal discs. We also studied a reporter transgene which expresses GFP in response to p53 activation by gamma radiation. We could confirm that this p53 surrogate works in imaginal discs as well as in embryos. This provided us a tool to quantify the effect on the GFP signal by overexpression of eIF4E to confirm how these two proteins could interact in vivo. Our results suggest that p53 and eIF4E are indeed in an equilibrium that decides if a cell shall proliferate or die. (authors)

  12. FGFR3 and P53 characterize alternative genetic pathways in the pathogenesis of urothelial cell carcinoma

    NARCIS (Netherlands)

    B.W. van Rhijn (Bas); Th.H. van der Kwast (Theo); A.N. Vis (André); W.J. Kirkels (Wim); E.R. Boeve; A.C. Jobsis; E.C. Zwarthoff (Ellen)

    2004-01-01

    textabstractFibroblast growth factor receptor 3 (FGFR3) and P53 mutations are frequently observed in bladder cancer. We here describe the distribution of FGFR3 mutations and P53 overexpression in 260 primary urothelial cell carcinomas. FGFR3 mutations were observed in 59% and P53

  13. A comparison of the effects of tributyltin chloride and triphenyltin chloride on cell proliferation, proapoptotic p53, Bax, and antiapoptotic Bcl-2 protein levels in human breast cancer MCF-7 cell line.

    Science.gov (United States)

    Fickova, Maria; Macho, Ladislav; Brtko, Julius

    2015-06-01

    In recent years it was disclosed, that numerous organotin(IV) derivatives have remarkable cytotoxicity against several types of cancer cells. The property to inhibit cell growth makes these compounds promising for antitumor therapy, as the clinical effectiveness of cisplatin is limited by drug resistance and significant side effects. Tributyltin and triphenyltin are known as endocrine disruptors. Moreover, the compounds exert their toxicity in mammals predominantly through nuclear receptor signaling. Here we present the effects of tributyltin chloride (TBT-Cl) and triphenyltin chloride (TPT-Cl) on cell proliferation, expression of proapoptotic p53, Bax, and antiapoptotic Bcl-2 proteins in human breast cancer MCF-7 cell line. Dose and time dependent (24, 48 and 72 h) cell expositions have demonstrated TBT-Cl as more effective in inhibiting MCF-7 cell proliferation than TPT-Cl. Short time treatment with TBT-Cl displayed marked stimulation of p53 protein expression when compared to TPT-Cl. Both organotin compounds displayed similar mild enhancement of Bax protein expression. The 24h exposition of TPT-Cl induced substantial diminution of Bcl-2 protein expression in comparison with both, untreated cells and TBT-Cl treated cells. Our observations indicate that TBT-Cl and TPT-Cl have different antiproliferative potency and distinct impact on expression of apoptosis marker proteins. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

    Tian, Kegui; Wang, Yuezeng; Huang, Yu; Sun, Boqiao; Li, Yuxin; Xu, Haopeng

    2008-01-01

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

  15. 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

    Full Text Available Sangiliyandi Gurunathan, Jung Hyun Park, Jae Woong Han, Jin-Hoi KimDepartment of Animal Biotechnology, Konkuk University, Seoul, Republic of KoreaBackground: Recently, the use of nanotechnology has been expanding very rapidly in diverse areas of research, such as consumer products, energy, materials, and medicine. This is especially true in the area of nanomedicine, due to physicochemical properties, such as mechanical, chemical, magnetic, optical, and electrical properties, compared with bulk materials. The first goal of this study was to produce silver nanoparticles (AgNPs using two different biological resources as reducing agents, Bacillus tequilensis and Calocybe indica. The second goal was to investigate the apoptotic potential of the as-prepared AgNPs in breast cancer cells. The final goal was to investigate the role of p53 in the cellular response elicited by AgNPs.Methods: The synthesis and characterization of AgNPs were assessed by various analytical techniques, including ultraviolet-visible (UV-vis spectroscopy, X-ray diffraction (XRD, Fourier transform infrared (FTIR spectroscopy, dynamic light scattering (DLS, and transmission electron microscopy (TEM. The apoptotic efficiency of AgNPs was confirmed using a series of assays, including cell viability, leakage of lactate dehydrogenase (LDH, production of reactive oxygen species (ROS, DNA fragmentation, mitochondrial membrane potential, and Western blot.Results: The absorption spectrum of the yellow AgNPs showed the presence of nanoparticles. XRD and FTIR spectroscopy results confirmed the crystal structure and biomolecules involved in the synthesis of AgNPs. The AgNPs derived from bacteria and fungi showed distinguishable shapes, with an average size of 20 nm. Cell viability assays suggested a dose-dependent toxic effect of AgNPs, which was confirmed by leakage of LDH, activation of ROS, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL-positive cells in MDA

  16. p53 Acetylation: Regulation and Consequences

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Sara M. [Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Medical Scientist Training Program, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Quelle, Dawn E., E-mail: dawn-quelle@uiowa.edu [Department of Pharmacology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Medical Scientist Training Program, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States); Department of Pathology, The University of Iowa Carver College of Medicine, Iowa City, IA 52242 (United States)

    2014-12-23

    Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity, selection of growth inhibitory vs. apoptotic gene targets, and biological outcomes in response to diverse cellular insults. Yet recent in vivo evidence from mouse models questions the importance of p53 acetylation (at least at certain sites) as well as canonical p53 functions (cell cycle arrest, senescence and apoptosis) to tumor suppression. This review discusses the cumulative findings regarding p53 acetylation, with a focus on the acetyltransferases that modify p53 and the mechanisms regulating their activity. We also evaluate what is known regarding the influence of other post-translational modifications of p53 on its acetylation, and conclude with the current outlook on how p53 acetylation affects tumor suppression. Due to redundancies in p53 control and growing understanding that individual modifications largely fine-tune p53 activity rather than switch it on or off, many questions still remain about the physiological importance of p53 acetylation to its role in preventing cancer.

  17. p53 Acetylation: Regulation and Consequences

    International Nuclear Information System (INIS)

    Reed, Sara M.; Quelle, Dawn E.

    2014-01-01

    Post-translational modifications of p53 are critical in modulating its tumor suppressive functions. Ubiquitylation, for example, plays a major role in dictating p53 stability, subcellular localization and transcriptional vs. non-transcriptional activities. Less is known about p53 acetylation. It has been shown to govern p53 transcriptional activity, selection of growth inhibitory vs. apoptotic gene targets, and biological outcomes in response to diverse cellular insults. Yet recent in vivo evidence from mouse models questions the importance of p53 acetylation (at least at certain sites) as well as canonical p53 functions (cell cycle arrest, senescence and apoptosis) to tumor suppression. This review discusses the cumulative findings regarding p53 acetylation, with a focus on the acetyltransferases that modify p53 and the mechanisms regulating their activity. We also evaluate what is known regarding the influence of other post-translational modifications of p53 on its acetylation, and conclude with the current outlook on how p53 acetylation affects tumor suppression. Due to redundancies in p53 control and growing understanding that individual modifications largely fine-tune p53 activity rather than switch it on or off, many questions still remain about the physiological importance of p53 acetylation to its role in preventing cancer

  18. DRAGO (KIAA0247), a new DNA damage-responsive, p53-inducible gene that cooperates with p53 as oncosuppressor. [Corrected].

    Science.gov (United States)

    Polato, Federica; Rusconi, Paolo; Zangrossi, Stefano; Morelli, Federica; Boeri, Mattia; Musi, Alberto; Marchini, Sergio; Castiglioni, Vittoria; Scanziani, Eugenio; Torri, Valter; Broggini, Massimo

    2014-04-01

    p53 influences genomic stability, apoptosis, autophagy, response to stress, and DNA damage. New p53-target genes could elucidate mechanisms through which p53 controls cell integrity and response to damage. DRAGO (drug-activated gene overexpressed, KIAA0247) was characterized by bioinformatics methods as well as by real-time polymerase chain reaction, chromatin immunoprecipitation and luciferase assays, time-lapse microscopy, and cell viability assays. Transgenic mice (94 p53(-/-) and 107 p53(+/-) mice on a C57BL/6J background) were used to assess DRAGO activity in vivo. Survival analyses were performed using Kaplan-Meier curves and the Mantel-Haenszel test. All statistical tests were two-sided. We identified DRAGO as a new p53-responsive gene induced upon treatment with DNA-damaging agents. DRAGO is highly conserved, and its ectopic overexpression resulted in growth suppression and cell death. DRAGO(-/-) mice are viable without macroscopic alterations. However, in p53(-/-) or p53(+/-) mice, the deletion of both DRAGO alleles statistically significantly accelerated tumor development and shortened lifespan compared with p53(-/-) or p53(+/-) mice bearing wild-type DRAGO alleles (p53(-/-), DRAGO(-/-) mice: hazard ratio [HR] = 3.25, 95% confidence interval [CI] = 1.7 to 6.1, P < .001; p53(+/-), DRAGO(-/-) mice: HR = 2.35, 95% CI = 1.3 to 4.0, P < .001; both groups compared with DRAGO(+/+) counterparts). DRAGO mRNA levels were statistically significantly reduced in advanced-stage, compared with early-stage, ovarian tumors, but no mutations were found in several human tumors. We show that DRAGO expression is regulated both at transcriptional-through p53 (and p73) and methylation-dependent control-and post-transcriptional levels by miRNAs. DRAGO represents a new p53-dependent gene highly regulated in human cells and whose expression cooperates with p53 in tumor suppressor functions.

  19. p53 mutations promote proteasomal activity.

    Science.gov (United States)

    Oren, Moshe; Kotler, Eran

    2016-07-27

    p53 mutations occur very frequently in human cancer. Besides abrogating the tumour suppressive functions of wild-type p53, many of those mutations also acquire oncogenic gain-of-function activities. Augmentation of proteasome activity is now reported as a common gain-of-function mechanism shared by different p53 mutants, which promotes cancer resistance to proteasome inhibitors.

  20. A Unique Mdm2-Binding Mode of the 3-Pyrrolin-2-one- and 2-Furanone-Based Antagonists of the p53-Mdm2 Interaction

    NARCIS (Netherlands)

    Surmiak, Ewa; Twarda-Clapa, Aleksandra; Zak, Krzysztof M.; Musielak, Bogdan; Tomala, Marcin D.; Kubica, Katarzyna; Grudnik, Przemyslaw; Madej, Mariusz; Jablonski, Mateusz; Potempa, Jan; Kalinowska-Tluscik, Justyna; Dömling, Alexander; Dubin, Grzegorz; Holak, Tad A.

    2016-01-01

    The p53 pathway is inactivated in almost all types of cancer by mutations in the p53 encoding gene or overexpression of the p53 negative regulators, Mdm2 and/or Mdmx. Restoration of the p53 function by inhibition of the p53-Mdm2/Mdmx interaction opens up a prospect for a nongenotoxic anticancer

  1. PTEN expression as a predictor for the response to trastuzumab-based therapy in Her-2 overexpressing metastatic breast cancer.

    Directory of Open Access Journals (Sweden)

    Daphne Gschwantler-Kaulich

    Full Text Available Even though trastuzumab is an effective therapy in early stage Her-2+ breast cancer, 40-50% of advanced Her-2+ breast cancer patients develop trastuzumab resistance. A potential resistance mechanism is aberrant downstream signal transmission due to loss of phosphatase and tensin homologue (PTEN. This study investigated the relationship between the expression of PTEN and trastuzumab response in Her-2 overexpressing metastatic breast cancer patients.Between 2000 and 2007, 164 patients with Her-2+ metastatic breast cancer received trastuzumab-based therapy in our institution. We analyzed PTEN status by immunohistochemistry of 115 available tumor tissues and analyzed associations with other histopathological parameters, response rate, progression free survival (PFS and overall survival (OS with a median follow-up of 60 months.Eighty patients were PTEN positive (69.6% and 35 patients PTEN negative (30.4%. We found a significant association of the expression of PTEN and p53 (p = 0.041, while there was no association with grading, hormone receptor status, IGFR or MIB. We found significantly more cases with progressive disease under trastuzumab-based therapy in patients with PTEN positive breast cancers (p = 0.018, while there was no significant correlation with PFS or OS.In Her-2-positive metastatic breast cancers, PTEN positivity was significantly associated with progressive disease, but not with PFS or OS.

  2. BRCA1-IRIS Overexpression Promotes Formation of Aggressive Breast Cancers

    Science.gov (United States)

    Shimizu, Yoshiko; Luk, Hugh; Horio, David; Miron, Penelope; Griswold, Michael; Iglehart, Dirk; Hernandez, Brenda; Killeen, Jeffrey; ElShamy, Wael M.

    2012-01-01

    Introduction Women with HER2+ or triple negative/basal-like (TN/BL) breast cancers succumb to their cancer rapidly due, in part to acquired Herceptin resistance and lack of TN/BL-targeted therapies. BRCA1-IRIS is a recently discovered, 1399 residue, BRCA1 locus alternative product, which while sharing 1365 residues with the full-length product of this tumor suppressor gene, BRCA1/p220, it has oncoprotein-like properties. Here, we examine whether BRCA1-IRIS is a valuable treatment target for HER2+ and/or TN/BL tumors. Methodology/Principal Findings Immunohistochemical staining of large cohort of human breast tumor samples using new monoclonal anti-BRCA1-IRIS antibody, followed by correlation of BRCA1-IRIS expression with that of AKT1, AKT2, p-AKT, survivin and BRCA1/p220, tumor status and age at diagnosis. Generation of subcutaneous tumors in SCID mice using human mammary epithelial (HME) cells overexpressing TERT/LT/BRCA1-IRIS, followed by comparing AKT, survivin, and BRCA1/p220 expression, tumor status and aggressiveness in these tumors to that in tumors developed using TERT/LT/RasV12-overexpressing HME cells. Induction of primary and invasive rat mammary tumors using the carcinogen N-methyl-N-nitrosourea (NMU), followed by analysis of rat BRCA1-IRIS and ERα mRNA levels in these tumors. High BRCA1-IRIS expression was detected in the majority of human breast tumors analyzed, which was positively correlated with that of AKT1-, AKT2-, p-AKT-, survivin, but negatively with BRCA1/p220 expression. BRCA1-IRIS-positivity induced high-grade, early onset and metastatic HER2+ or TN/BL tumors. TERT/LT/BRCA1-IRIS overexpressing HME cells formed invasive subcutaneous tumors that express high AKT1, AKT2, p-AKT and vimentin, but no CK19, p63 or BRCA1/p220. NMU-induced primary and invasive rat breast cancers expressed high levels of rat BRCA1-IRIS mRNA but low levels of rat ERα mRNA. Conclusion/Significance BRCA1-IRIS overexpression triggers aggressive breast tumor formation

  3. Biologic effect of exogenous wild p53 combined with irradiation on human melanoma cell lines with different p53 status

    International Nuclear Information System (INIS)

    Min Fengling; Zhang Hong; Li Wenjian; Liu Bing; Zhou Qingming; Duan Xin; Gao Qingxiang

    2007-01-01

    Objective: To investigate the effect of low dose irradiation on gene transfer efficiency and the effect of adenoviral-mediated exogenous P53 overexpression on apoptosis and radiosensitivity of radioresistant human melanoma cell lines A375(wild type p53)and WM983a(mutant type p53). Methods: Control vector, a replication deficient recombinant adenoviral vector containing a CMV promoter and green fluorescent protein (AdCMV-GFP), was used to transfect A375 cells and WM983a cells preirradiated with or without 1 Gy X-ray. The transduction efficiency of GFP gene was determined with fluorescence microscope directly. These two types of cells irradiated by 1 Gy X-ray were transfected with a replication deficient recombinant adenoviral vector carrying human wild p53 (AdCMV-p53), and mRNA level was detected by RT-PCR. The cell cycle delay and the expression of exogenous P53 were detected using flow cytometry (FCM) at different times after transfection. Tunel technique was used to detect cell apoptosis. The radiosensivity of A375 and WM983a cells after p53 transduction was analyzed by colony formation. Results: It is found that 1 Gy irradiation increased the gene transfection efficiency of A375 and WM983a cells. The expression of exogenous P53 was found to range from 60% to 80% among transfected cells during the first three days after transduction and then declined continuously down to the control level on day 10. G 1 cell cycle arrest was also observed after p53 gene transduction. WM983a cells transfected with p53 showed higher sensitivity to X-ray-induced cell killing than A375 cells. Conclusions: It is indicated that low dose of ionizing radiation can improve gene transfection efficiency of A375 and WM983a cells mediated by adenovirus vector. Althrough the overexpresion of exogenous p53 may not inhibit cell growth and induce apoptosis of melanoma cell line A375 and WM983a irt vitro, the two cell lines are much more sensitive to cell death induced by irradiation. It is

  4. HER-2, p53, p21 and hormonal receptors proteins expression as predictive factors of response and prognosis in locally advanced breast cancer treated with neoadjuvant docetaxel plus epirubicin combination

    International Nuclear Information System (INIS)

    Tiezzi, Daniel G; Andrade, Jurandyr M; Ribeiro-Silva, Alfredo; Zola, Fábio E; Marana, Heitor RC; Tiezzi, Marcelo G

    2007-01-01

    Neoadjuvant chemotherapy has been considered the standard care in locally advanced breast cancer. However, about 20% of the patients do not benefit from this clinical treatment and, predictive factors of response were not defined yet. This study was designed to evaluate the importance of biological markers to predict response and prognosis in stage II and III breast cancer patients treated with taxane and anthracycline combination as neoadjuvant setting. Sixty patients received preoperative docetaxel (75 mg/m 2 ) in combination with epirubicin (50 mg/m 2 ) in i.v. infusion in D1 every 3 weeks after incisional biopsy. They received adjuvant chemotherapy with CMF or FEC, attaining axillary status following definitive breast surgery. Clinical and pathologic response rates were measured after preoperative therapy. We evaluated the response rate to neoadjuvant chemotherapy and the prognostic significance of clinicopathological and immunohistochemical parameters (ER, PR, p51, p21 and HER-2 protein expression). The median patient age was 50.5 years with a median follow up time 48 months after the time of diagnosis. Preoperative treatment achieved clinical response in 76.6% of patients and complete pathologic response in 5%. The clinical, pathological and immunohistochemical parameters were not able to predict response to therapy and, only HER2 protein overexpression was associated with a decrease in disease free and overall survival (P = 0.0007 and P = 0.003) as shown by multivariate analysis. Immunohistochemical phenotypes were not able to predict response to neoadjuvant chemotherapy. Clinical response is inversely correlated with a risk of death in patients submitted to neoadjuvant chemotherapy and HER2 overexpression is the major prognostic factor in stage II and III breast cancer patients treated with a neoadjuvant docetaxel and epirubicin combination

  5. The antagonism between MCT-1 and p53 affects the tumorigenic outcomes

    Directory of Open Access Journals (Sweden)

    Lin Tai-Du

    2010-12-01

    Full Text Available Abstract Background MCT-1 oncoprotein accelerates p53 protein degradation via a proteosome pathway. Synergistic promotion of the xenograft tumorigenicity has been demonstrated in circumstance of p53 loss alongside MCT-1 overexpression. However, the molecular regulation between MCT-1 and p53 in tumor development remains ambiguous. We speculate that MCT-1 may counteract p53 through the diverse mechanisms that determine the tumorigenic outcomes. Results MCT-1 has now identified as a novel target gene of p53 transcriptional regulation. MCT-1 promoter region contains the response elements reactive with wild-type p53 but not mutant p53. Functional p53 suppresses MCT-1 promoter activity and MCT-1 mRNA stability. In a negative feedback regulation, constitutively expressed MCT-1 decreases p53 promoter function and p53 mRNA stability. The apoptotic events are also significantly prevented by oncogenic MCT-1 in a p53-dependent or a p53-independent fashion, according to the genotoxic mechanism. Moreover, oncogenic MCT-1 promotes the tumorigenicity in mice xenografts of p53-null and p53-positive lung cancer cells. In support of the tumor growth are irrepressible by p53 reactivation in vivo, the inhibitors of p53 (MDM2, Pirh2, and Cop1 are constantly stimulated by MCT-1 oncoprotein. Conclusions The oppositions between MCT-1 and p53 are firstly confirmed at multistage processes that include transcription control, mRNA metabolism, and protein expression. MCT-1 oncogenicity can overcome p53 function that persistently advances the tumor development.

  6. Regulation of autophagy by cytoplasmic p53.

    Science.gov (United States)

    Tasdemir, Ezgi; Maiuri, M Chiara; Galluzzi, Lorenzo; Vitale, Ilio; Djavaheri-Mergny, Mojgan; D'Amelio, Marcello; Criollo, Alfredo; Morselli, Eugenia; Zhu, Changlian; Harper, Francis; Nannmark, Ulf; Samara, Chrysanthi; Pinton, Paolo; Vicencio, José Miguel; Carnuccio, Rosa; Moll, Ute M; Madeo, Frank; Paterlini-Brechot, Patrizia; Rizzuto, Rosario; Szabadkai, Gyorgy; Pierron, Gérard; Blomgren, Klas; Tavernarakis, Nektarios; Codogno, Patrice; Cecconi, Francesco; Kroemer, Guido

    2008-06-01

    Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53(-/-) cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.

  7. Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

    OpenAIRE

    Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

    1992-01-01

    Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-...

  8. The expanding universe of p53 targets.

    Science.gov (United States)

    Menendez, Daniel; Inga, Alberto; Resnick, Michael A

    2009-10-01

    The p53 tumour suppressor is modified through mutation or changes in expression in most cancers, leading to the altered regulation of hundreds of genes that are directly influenced by this sequence-specific transcription factor. Central to the p53 master regulatory network are the target response element (RE) sequences. The extent of p53 transactivation and transcriptional repression is influenced by many factors, including p53 levels, cofactors and the specific RE sequences, all of which contribute to the role that p53 has in the aetiology of cancer. This Review describes the identification and functionality of REs and highlights the inclusion of non-canonical REs that expand the universe of genes and regulation mechanisms in the p53 tumour suppressor network.

  9. 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.

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

    International Nuclear Information System (INIS)

    Huang, Shi-Wei; Wu, Chun-Ying; Wang, Yen-Ting; Kao, Jun-Kai; Lin, Chi-Chen; Chang, Chia-Che; Mu, Szu-Wei; Chen, Yu-Yu; Chiu, Husan-Wen; Chang, Chuan-Hsun; Liang, Shu-Mei; Chen, Yi-Ju; Huang, Jau-Ling; Shieh, Jeng-Jer

    2013-01-01

    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

  11. Assessment of the potential diagnostic value of serum p53 antibody for cancer: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    Full Text Available BACKGROUND: Mutant p53 protein over-expression has been reported to induce serum antibodies against p53. We assessed the diagnostic precision of serum p53 (s-p53 antibodies for diagnosis of cancer patients and compared the positive rates of the s-p53 antibody in different types of cancers. METHODS: We systematically searched PubMed and Embase, through May 31, 2012. Studies were assessed for quality using QUADAS (quality assessment of studies of diagnostic accuracy. The positive likelihood ratio (PLR and negative likelihood ratio (NLR were pooled separately and compared with overall accuracy measures using diagnostic odds ratios (DORs and Area under the curve(AUC. Meta regression and subgroup analyses were done, and heterogeneity and publication bias were assessed. RESULTS: Of 1089 studies initially identified, 100 eligible studies with 23 different types of tumor met the inclusion criteria for the meta-analysis (cases = 15953, controls = 8694. However, we could conduct independent meta analysis on only 13 of 36 types of tumors. Approximately 56% (56/100 of the included studies were of high quality (QUADAS score≥8. The summary estimates for quantitative analysis of serum p53 antibody in the diagnosis of cancers were: PLR 5.75 (95% CI: 4.60-7.19, NLR 0.81 (95%CI: 0.79-0.83 and DOR 7.56 (95% CI: 6.02-9.50. However, for the 13 types of cancers on which meta-analysis was conducted, the ranges for PLR (2.33-11.05, NLR (0.74-0.97, DOR (2.86-13.80, AUC(0.29-0.81, and positive rate (4.47%-28.36% indicated significant heterogeneity. We found that breast, colorectal, esophageal, gastric, hepatic, lymphoma, lung and ovarian cancer had relatively reasonable diagnostic accuracy. The remaining results of the five types of cancers suggested that s-p53 antibody had limited value. CONCLUSIONS: The current evidence suggests that s-p53 antibody has potential diagnostic value for cancer, especially for breast, colorectal, esophageal, gastric, hepatic

  12. Both p53-PUMA/NOXA-Bax-mitochondrion and p53-p21cip1 pathways are involved in the CDglyTK-mediated tumor cell suppression

    International Nuclear Information System (INIS)

    Yu, Zhendong; Wang, Hao; Zhang, Libin; Tang, Aifa; Zhai, Qinna; Wen, Jianxiang; Yao, Li; Li, Pengfei

    2009-01-01

    CDglyTK fusion suicide gene has been well characterized to effectively kill tumor cells. However, the exact mechanism and downstream target genes are not fully understood. In our study, we found that CDglyTK/prodrug treatment works more efficiently in p53 wild-type (HONE1) cells than in p53 mutant (CNE1) cells. We then used adenovirus-mediated gene delivery system to either knockdown or overexpress p53 and its target genes in these cells. Consistent results showed that both p53-PUMA/NOXA/Bcl2-Bax and p53-p21 pathways contribute to the CDglyTK induced tumor cell suppression. Our work for the first time addressed the role of p53 related genes in the CDglyTK/prodrug system.

  13. Both p53-PUMA/NOXA-Bax-mitochondrion and p53-p21cip1 pathways are involved in the CDglyTK-mediated tumor cell suppression

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhendong, E-mail: zdyu@hotmail.com [Department of Clinical laboratory, Peking University Shenzhen Hospital, Guangdong (China); Wang, Hao [Department of pathology, The Chinese University of Hong Kong, Hong Kong (China); Zhang, Libin; Tang, Aifa; Zhai, Qinna; Wen, Jianxiang; Yao, Li [Department of Clinical laboratory, Peking University Shenzhen Hospital, Guangdong (China); Li, Pengfei, E-mail: lipengfei@cuhk.edu.hk [Department of pathology, The Chinese University of Hong Kong, Hong Kong (China)

    2009-09-04

    CDglyTK fusion suicide gene has been well characterized to effectively kill tumor cells. However, the exact mechanism and downstream target genes are not fully understood. In our study, we found that CDglyTK/prodrug treatment works more efficiently in p53 wild-type (HONE1) cells than in p53 mutant (CNE1) cells. We then used adenovirus-mediated gene delivery system to either knockdown or overexpress p53 and its target genes in these cells. Consistent results showed that both p53-PUMA/NOXA/Bcl2-Bax and p53-p21 pathways contribute to the CDglyTK induced tumor cell suppression. Our work for the first time addressed the role of p53 related genes in the CDglyTK/prodrug system.

  14. The p53-dependent radioadaptive response

    Science.gov (United States)

    Ohnishi, Takeo

    We already reported that conditioning exposures at low doses, or at low dose-rates, lowered radiation-induced p53-dependent apoptosis in cultured cells in vitro and in the spleens of mice in vivo. In this study, the aim was to characterize the p53-dependent radioadaptive response at the molecular level. We used wild-type (wt) p53 and mutated (m) p53 containing cells derived from the human lung cancer H1299 cell line, which is p53-null. Cellular radiation sensitivities were determined with a colony-forming assay. The accumulation of p53, Hdm2, and iNOS was analyzed with Western blotting. The quantification of chromosomal aberrations was estimated by scoring dicentrics per cell. In wtp53 cells, it was demonstrated that the lack of p53 accumulation was coupled with the activation of Hdm2 after low dose irradiation (0.02 Gy). Although NO radicals were only minimally induced in wtp53 cells irradiated with a challenging irradiation (6 Gy) alone, NO radicals were seen to increase about 2-4 fold after challenging irradiation following a priming irradiation (0.02 Gy). Under similar irradiation conditions with a priming and challenging irradiation in wtp53 cells, induction of radioresistance and a depression of chromosomal aberrations were observed only in the absence of Pifithrin-α (a p53 inhibitor), RITA or Nutlin-3 (p53-Hdm2 interaction inhibitors), aminoguanidine (an iNOS inhibitor) and c-PTIO (an NO radical scavenger). On the other hand, in p53 dysfunctional cells, a radioadaptive response was not observed in the presence or absence of those inhibitors. Moreover, radioresistance developed when wtp53 cells were treated with ISDN (an NO generating agent) alone. These findings suggest that NO radicals are an initiator of the radioadaptive response acting through the activation of Hdm2 and the depression of p53 accumulations.

  15. Expression of p53 in oligodendrogliomas

    NARCIS (Netherlands)

    J.M. Kros (Johan); J.J.C.J. Godschalk (J. J C J); K.K. Krishnadath (Kausilia); C.G. van Eden (C.)

    1993-01-01

    textabstractThe expression of the nuclear protein p53 in oligodendrogliomas was investigated by immunohistochemistry, using a monoclonal anti-p53 antibody (DO-7) on formalin-fixed, paraffin-embedded material in 84 histologically verified cases, and compared with the histopathological grade and

  16. Expression of p53 in oligodendrogliomas

    NARCIS (Netherlands)

    Kros, J. M.; Godschalk, J. J.; Krishnadath, K. K.; van Eden, C. G.

    1993-01-01

    The expression of the nuclear protein p53 in oligodendrogliomas was investigated by immunohistochemistry, using a monoclonal anti-p53 antibody (DO-7) on formalin-fixed, paraffin-embedded material in 84 histologically verified cases, and compared with the histopathological grade and survival.

  17. Evaluation of Single Nucleotide Polymorphisms (SNPs) in the p53 Binding Protein 1 (TP53BP1) Gene in Breast Cancer Patients Treated With Breast-Conserving Surgery and Whole-Breast Irradiation (BCS + RT)

    International Nuclear Information System (INIS)

    Haffty, Bruce G.; Goyal, Sharad; Kulkarni, Diptee; Green, Camille; Vazquez, Alexi; Schiff, Devora; Moran, Meena S.; Yang Qifeng; Ganesan, Shridar; Hirsfield, Kim M.

    2011-01-01

    Purpose: TP53BP1 is a key component of radiation-induced deoxyribonucleic acid damage repair. The purpose of this study was to evaluate the significance of a known common single nucleotide polymorphism in this gene (rs560191) in patients treated with breast-conserving surgery and whole-breast irradiation (BCS + RT). Methods and Materials: The population consisted of 176 premenopausal women treated with BCS + RT (median follow-up, 12 years). Genomic deoxyribonucleic acid was processed by use of TaqMan assays. Each allele for rs560191 was either C or G, so each patient was therefore classified as CC, CG, or GG. Patients were grouped as GG if they were homozygous for the variant G allele or CC-CG if they carried at least one copy of the common C allele (CC or CG). Results: Of the 176 women, 124 (71%) were CC-CG and 52 (29%) were GG. The mean age was 44 years for GG vs. 38 years for CC-CG (p < 0.001). GG was more common in African-American women than white women (69% vs. 13%, p < 0.001) and more commonly estrogen receptor negative (70% vs. 49%, p = 0.02). There were no significant correlations of rs560191 with other critical variables. Despite the fact that GG patients were older, the 10-year rate of local relapses was higher (22% for GG vs. 12% for CC-CG, p = 0.04). Conclusions: This novel avenue of investigation of polymorphisms in radiation repair/response genes in patients treated with BCS + RT suggests a correlation to local relapse. Additional evaluation is needed to assess the biological and functional significance of these single nucleotide polymorphisms, and larger confirmatory validation studies will be required to determine the clinical implications.

  18. Microbial Regulation of p53 Tumor Suppressor.

    Directory of Open Access Journals (Sweden)

    Alexander I Zaika

    2015-09-01

    Full Text Available p53 tumor suppressor has been identified as a protein interacting with the large T antigen produced by simian vacuolating virus 40 (SV40. Subsequent research on p53 inhibition by SV40 and other tumor viruses has not only helped to gain a better understanding of viral biology, but also shaped our knowledge of human tumorigenesis. Recent studies have found, however, that inhibition of p53 is not strictly in the realm of viruses. Some bacterial pathogens also actively inhibit p53 protein and induce its degradation, resulting in alteration of cellular stress responses. This phenomenon was initially characterized in gastric epithelial cells infected with Helicobacter pylori, a bacterial pathogen that commonly infects the human stomach and is strongly linked to gastric cancer. Besides H. pylori, a number of other bacterial species were recently discovered to inhibit p53. These findings provide novel insights into host-bacteria interactions and tumorigenesis associated with bacterial infections.

  19. miR-34 and p53: New Insights into a Complex Functional Relationship.

    Directory of Open Access Journals (Sweden)

    Francisco Navarro

    Full Text Available miR-34, a tumor suppressor miRNA family transcriptionally activated by p53, is considered a critical mediator of p53 function. However, knockout of the mouse miR-34 family has little or no effect on the p53 response. The relative contribution of different miR-34 family members to p53 function or how much p53 relies on miR-34 in human cells is unclear. Here we show that miR-34a has a complex effect on the p53 response in human cells. In HCT116 cells miR-34a overexpression enhances p53 transcriptional activity, but the closely related family members, miR-34b and miR-34c, even when over-expressed, have little effect. Both TP53 itself and MDM4, a strong p53 transactivation inhibitor, are direct targets of miR-34a. The genes regulated by miR-34a also include four other post-translational inhibitors of p53. miR-34a overexpression leads to variable effects on p53 levels in p53-sufficient human cancer cell lines. In HCT116, miR-34a overexpression increases p53 protein levels and stability. About a quarter of all mRNAs that participate in the human p53 network bind to biotinylated miR-34a, suggesting that many are direct miR-34a targets. However, only about a fifth of the mRNAs that bind to miR-34a also bind to miR-34b or miR-34c. Two human cell lines knocked out for miR-34a have unimpaired p53-mediated responses to genotoxic stress, like mouse cells. The complex positive and negative effects of miR-34 on the p53 network suggest that rather than simply promoting the p53 response, miR-34a might act at a systems level to stabilize the robustness of the p53 response to genotoxic stress.

  20. p53 in differentiation of thyroid cancer

    International Nuclear Information System (INIS)

    Seyama, Toshio; Ito, Takashi; Akiyama, Mitoshi; Hayashi, Yuzo; Dohi, Kiyohiko.

    1993-01-01

    P53 is a tumor suppressor gene with such a recessive nature and is inactivated in many carcinomas. DNA was extracted from 10 primary papillary adenocarcinomas and eight undifferentiated carcinomas of the thyroid, using three 5 μm sliced paraffin segments, and then amplified by PCR. The products were analyzed for mutations in the p53 gene exons 5 to 8 by the direct sequencing method and for allelic deletion by the RFLP method. In five human thyroid carcinomas, DNA was extracted from each tissue and analyzed. Mutations in the p53 gene exons 5 to 8 and p53 gene deletions were not detected in the 10 papillary adenocarcinomas, mutations were detected in seven of eight cases and allelic deletions was detected in three of the five cases examined. In each of the five cases which had both differentiated and undifferentiated tissues in the same tumor, p53 gene mutations were not detected in the differentiated tissues while mutations and gene deletions were detected in the undifferentiated sections. The p53 gene was analyzed using paraffin-embedded tissues by the combined use of the direct sequencing and PCR methods and by the RFLP method. It was found that the progression of human thyroid carcinoma is closely related to the p53 genetic changes. Furthermore, the analysis of differentiated and undifferentiated tissues in the same tumor showed that human undifferentiated thyroid carcinomas develop from differentiated carcinomas. (J.P.N.)

  1. Overexpression of prostate tumor overexpressed 1 correlates with tumor progression and predicts poor prognosis in breast cancer

    International Nuclear Information System (INIS)

    Lei, Fangyong; Zhang, Longjuan; Li, Xinghua; Lin, Xi; Wu, Shu; Li, Fengyan; Liu, Junling

    2014-01-01

    Prostate tumor overexpressed 1 (PTOV1) was demonstrated to play an important role in cancer progression and was correlated with unfavorable clinical outcome. However, the clinical role of PTOV1 in cancer remains largely unknown. This study aimed to investigate the expression and clinicopathological significance of PTOV1 in breast cancer. The mRNA and protein expression levels of PTOV1 were analyzed in 12 breast cancer cell lines and eight paired breast cancer tumors by semi-quantitative real time-PCR and western blotting, respectively. Immunohistochemistry was performed to assess PTOV1 protein expression in 169 paraffin-embedded, archived breast cancer samples. Survival analysis and Cox regression analysis were performed to investigate the clinicopathological significance of PTOV1 expression. Our data revealed that PTOV1 was frequently overexpressed in breast cancer cell lines compared to normal human breast epithelial cells and in primary breast cancer samples compared to adjacent noncancerous breast tissues, at both the mRNA and protein levels. Moreover, high expression of PTOV1 in breast cancer is strongly associated with clinicopathological characteristics and estrogen receptor expression status (P = 0.003). Breast cancer patients with higher PTOV1 expression had substantially shorter survival times than patients with lower PTOV1 expression (P < 0.001). Univariate and multivariate analysis revealed that PTOV1 might be an independent prognostic factor for breast cancer patients (P = 0.005). Our study showed that PTOV1 is upregulated in breast cancer cell lines and clinical samples, and its expression was positively associated with progression and aggressiveness of breast cancer, suggesting that PTOV1 could serve as an independent prognostic marker

  2. p53 functions as a cell cycle control protein in osteosarcomas.

    OpenAIRE

    Diller, L; Kassel, J; Nelson, C E; Gryka, M A; Litwak, G; Gebhardt, M; Bressac, B; Ozturk, M; Baker, S J; Vogelstein, B

    1990-01-01

    Mutations in the p53 gene have been associated with a wide range of human tumors, including osteosarcomas. Although it has been shown that wild-type p53 can block the ability of E1a and ras to cotransform primary rodent cells, it is poorly understood why inactivation of the p53 gene is important for tumor formation. We show that overexpression of the gene encoding wild-type p53 blocks the growth of osteosarcoma cells. The growth arrest was determined to be due to an inability of the transfect...

  3. Inability of p53-reactivating compounds Nutlin-3 and RITA to overcome p53 resistance in tumor cells deficient in p53Ser46 phosphorylation.

    Science.gov (United States)

    Ma, Teng; Yamada, Shumpei; Ichwan, Solachuddin J A; Iseki, Sachiko; Ohtani, Kiyoshi; Otsu, Megumi; Ikeda, Masa-Aki

    2012-01-20

    The p53 tumor suppressor protein plays key roles in protecting cells from tumorigenesis. Phosphorylation of p53 at Ser46 (p53Ser46) is considered to be a crucial modification regulating p53-mediated apoptosis. Because the activity of p53 is impaired in most human cancers, restoration of wild-type p53 (wt-p53) function by its gene transfer or by p53-reactivating small molecules has been extensively investigated. The p53-reactivating compounds Nutlin-3 and RITA activate p53 in the absence of genotoxic stress by antagonizing the action of its negative regulator Mdm2. Although controversial, Nutlin-3 was shown to induce p53-mediated apoptosis in a manner independent of p53 phosphorylation. Recently, RITA was shown to induce apoptosis by promoting p53Ser46 phosphorylation. Here we examined whether Nutlin-3 or RITA can overcome resistance to p53-mediated apoptosis in p53-resistant tumor cell lines lacking the ability to phosphorylate p53Ser46. We show that Nutlin-3 did not rescue the apoptotic defect of a Ser46 phosphorylation-defective p53 mutant in p53-sensitive tumor cells, and that RITA neither restored p53Ser46 phosphorylation nor induced apoptosis in p53Ser46 phosphorylation-deficient cells retaining wt-p53. Furthermore, treatment with Nutlin-3 or RITA together with adenoviral p53 gene transfer also failed to induce apoptosis in p53Ser46 phosphorylation-deficient cells either expressing or lacking wt-p53. These results indicate that neither Nutlin-3 nor RITA in able to induce p53-mediated apoptosis in the absence of p53Ser46 phosphorylation. Thus, the dysregulation of this phosphorylation in tumor cells may be a critical factor that limits the efficacy of these p53-based cancer therapies. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Glycerol restores the p53 function in human lingual cancer cells bearing mutant p53

    International Nuclear Information System (INIS)

    Ota, Ichiro; Yane, Katsunari; Yuki, Kazue; Kanata, Hirokazu; Hosoi, Hiroshi; Miyahara, Hiroshi

    2001-01-01

    Mutations in p53, tumor suppressor gene, have recently been shown to have an impact on the clinical course of several human tumors, including head and neck cancers. The genetic status of the p53 gene has been focused on as the most important candidate among various cancer-related genes for prognosis-predictive assays of cancer therapy. We examined the restoration of radiation- or cisplatin (CDDP)-induced p53-dependent apoptosis in human lingual cancer cells. The results suggest that glycerol is effective in inducing a conformational change of p53 and restoring normal function of mutant p53, leading to enhanced radiosensitivity or chemosensitivity through the induction of apoptosis. We have also represented the same results in vivo as in vitro. Thus, this novel tool for enhancement of radiosensitivity or chemosensitivity in cancer cells bearing m p53 may be applicable for p53-targeted cancer therapy. (author)

  5. Pigmentation, Melanocyte Colonization, and p53 Status in Basal Cell Carcinoma

    International Nuclear Information System (INIS)

    Frey, L. M.; Houben, R.; Brocker, E. B.

    2011-01-01

    Basal cell carcinoma (BCC) is the most common neoplasm in the Caucasian population. Only a fraction of BCC exhibits pigmentation. Lack of melanocyte colonization has been suggested to be due to p53-inactivating mutations in the BCC cells interfering with the p53-proopiomelanocortin pathway and the production of alpha melanocyte-stimulating hormone in the tumor. To evaluate this, we determined tumor pigmentation as well as expression of melan-A and of p53 in 49 BCC tissues by means of immunohistochemistry. As expected, we observed a positive relation between tumor pigmentation and melan-A positive intra-tumoral melanocytes. Melanocyte colonization and, to a lesser extent, p53 overexpression showed intraindividual heterogeneity in larger tumors. p53 overexpression, which is indicative of p53 mutations, was not correlated to melanocyte colonization of BCC. Sequencing of exon 5-8 of the p53 gene in selected BCC cases revealed that colonization by melanocytes and BCC pigmentation is neither ablated by p53 mutations nor generally present in BCCs with wild-type p53.

  6. p53-Induced Apoptosis Occurs in the Absence of p14ARF in Malignant Pleural Mesothelioma

    Directory of Open Access Journals (Sweden)

    Sally Hopkins-Donaldson

    2006-07-01

    Full Text Available Malignant pleural mesotheliomas (MPMs are usually wild type for the p53 gene but contain homozygous deletions in the INK4A locus that encodes p14ARF, an inhibitor of p53-MDM2 interaction. Previous findings suggest that lack of p14ARF expression and the presence of SV40 large T antigen (L-Tag result in p53 inactivation in MPM. We did not detect SV40 L-Tag mRNA in either MPM cell lines or primary cultures, treatment of p14ARF-deficient cells with cisplatin (CDDP increased both total and phosphorylated p53 and enhanced p53 DNA-binding activity. On incubation with CDDP, levels of positively regulated p53 transcriptional targets p21WAF, PIG3, MDM2, Bax, PUMA increased in p14ARF-deficient cells, whereas negatively regulated survivin decreased. Significantly, p53-induced apoptosis was activated by CDDP in p14ARF-deficient cells, treatment with p53-specific siRNA rendered them more CDDP-resistant. p53 was also activated by: 1 inhibition of MDM2 (using nutlin-3; 2 transient overexpression of p14ARF; and 3 targeting of survivin using antisense oligonucleotides. However, it is noteworthy that only survivin downregulation sensitized cells to CDDP-induced apoptosis. These results suggest that p53 is functional in the absence of p14ARF in MPM and that targeting of the downstream apoptosis inhibitor survivin can sensitize to CDDP-induced apoptosis.

  7. P53- and mevalonate pathway–driven malignancies require Arf6 for metastasis and drug resistance

    Science.gov (United States)

    Hashimoto, Ari; Oikawa, Tsukasa; Hashimoto, Shigeru; Sugino, Hirokazu; Yoshikawa, Ayumu; Otsuka, Yutaro; Handa, Haruka; Onodera, Yasuhito; Nam, Jin-Min; Oneyama, Chitose; Okada, Masato; Fukuda, Mitsunori

    2016-01-01

    Drug resistance, metastasis, and a mesenchymal transcriptional program are central features of aggressive breast tumors. The GTPase Arf6, often overexpressed in tumors, is critical to promote epithelial–mesenchymal transition and invasiveness. The metabolic mevalonate pathway (MVP) is associated with tumor invasiveness and known to prenylate proteins, but which prenylated proteins are critical for MVP-driven cancers is unknown. We show here that MVP requires the Arf6-dependent mesenchymal program. The MVP enzyme geranylgeranyl transferase II (GGT-II) and its substrate Rab11b are critical for Arf6 trafficking to the plasma membrane, where it is activated by receptor tyrosine kinases. Consistently, mutant p53, which is known to support tumorigenesis via MVP, promotes Arf6 activation via GGT-II and Rab11b. Inhibition of MVP and GGT-II blocked invasion and metastasis and reduced cancer cell resistance against chemotherapy agents, but only in cells overexpressing Arf6 and components of the mesenchymal program. Overexpression of Arf6 and mesenchymal proteins as well as enhanced MVP activity correlated with poor patient survival. These results provide insights into the molecular basis of MVP-driven malignancy. PMID:27044891

  8. 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

  9. Mutant, wild type, or overall p53 expression: freedom from clinical progression in tumours of astrocytic lineage.

    Science.gov (United States)

    Pardo, F S; Hsu, D W; Zeheb, R; Efird, J T; Okunieff, P G; Malkin, D M

    2004-11-01

    Abnormalities of the p53 tumor-suppressor gene are found in a significant proportion of astrocytic brain tumours. We studied tumour specimens from 74 patients evaluated over 20 years at the Massachusetts General Hospital, where clinical outcome could be determined and sufficient pathologic material was available for immunostaining. p53 expression studies employed an affinity-purified p53 monoclonal antibody, whose specificity was verified in absorption studies and, in a minority of cases, a second antibody recognising a different epitope of p53. Significant overexpression of p53 protein was found in 48% of the 74 tumours included in this series and high levels of expression were associated with higher mortality from astrocytic tumours (Pexpression of p53 plays an important role in the pathobiology of these tumours. In a subset of 36 cases, coding regions of the p53 gene were completely sequenced via SSCP and direct DNA sequencing, revealing that overexpression of p53 protein is not always associated with point mutations in conserved exons of the p53 gene. Finally, we confirmed p53 protein expression in early-passage human glioma cell lines of known p53 mutational status and immunostaining scores. Although grade continues to be the strongest prognostic variable, the use of p53 staining as a prognostic indicator, in contrast to mutational DNA analyses, may be a useful adjunct in identifying patients at higher risk of treatment failure.

  10. Regulation of Metabolic Activity by p53

    Directory of Open Access Journals (Sweden)

    Jessica Flöter

    2017-05-01

    Full Text Available Metabolic reprogramming in cancer cells is controlled by the activation of multiple oncogenic signalling pathways in order to promote macromolecule biosynthesis during rapid proliferation. Cancer cells also need to adapt their metabolism to survive and multiply under the metabolically compromised conditions provided by the tumour microenvironment. The tumour suppressor p53 interacts with the metabolic network at multiple nodes, mostly to reduce anabolic metabolism and promote preservation of cellular energy under conditions of nutrient restriction. Inactivation of this tumour suppressor by deletion or mutation is a frequent event in human cancer. While loss of p53 function lifts an important barrier to cancer development by deleting cell cycle and apoptosis checkpoints, it also removes a crucial regulatory mechanism and can render cancer cells highly sensitive to metabolic perturbation. In this review, we will summarise the major concepts of metabolic regulation by p53 and explore how this knowledge can be used to selectively target p53 deficient cancer cells in the context of the tumour microenvironment.

  11. 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

    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...

  12. Overexpression of a novel cell cycle regulator ecdysoneless in breast cancer: a marker of poor prognosis in HER2/neu-overexpressing breast cancer patients.

    Science.gov (United States)

    Zhao, Xiangshan; Mirza, Sameer; Alshareeda, Alaa; Zhang, Ying; Gurumurthy, Channabasavaiah Basavaraju; Bele, Aditya; Kim, Jun Hyun; Mohibi, Shakur; Goswami, Monica; Lele, Subodh M; West, William; Qiu, Fang; Ellis, Ian O; Rakha, Emad A; Green, Andrew R; Band, Hamid; Band, Vimla

    2012-07-01

    Uncontrolled proliferation is one of the hallmarks of breast cancer. We have previously identified the human Ecd protein (human ortholog of Drosophila Ecdysoneless, hereafter called Ecd) as a novel promoter of mammalian cell cycle progression, a function related to its ability to remove the repressive effects of Rb-family tumor suppressors on E2F transcription factors. Given the frequent dysregulation of cell cycle regulatory components in human cancer, we used immunohistochemistry of paraffin-embedded tissues to examine Ecd expression in normal breast tissue versus tissues representing increasing breast cancer progression. Initial studies of a smaller cohort without outcomes information showed that Ecd expression was barely detectable in normal breast tissue and in hyperplasia of breast, but high levels of Ecd were detected in benign breast hyperplasia, ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDCs) of the breast. In this cohort of 104 IDC patients, Ecd expression levels showed a positive correlation with higher grade (P=0.04). Further analyses of Ecd expression using a larger, independent cohort (954) confirmed these results, with a strong positive correlation of elevated Ecd expression with higher histological grade (P=0.013), mitotic index (P=0.032), and Nottingham Prognostic Index score (P=0.014). Ecd expression was positively associated with HER2/neu (P=0.002) overexpression, a known marker of poor prognosis in breast cancer. Significantly, increased Ecd expression showed a strong positive association with shorter breast cancer specific survival (BCSS) (P=0.008) and disease-free survival (DFS) (P=0.003) in HER2/neu overexpressing patients. Taken together, our results reveal Ecd as a novel marker for breast cancer progression and show that levels of Ecd expression predict poorer survival in Her2/neu overexpressing breast cancer patients.

  13. E2F-1-Induced p53-independent apoptosis in transgenic mice

    DEFF Research Database (Denmark)

    Holmberg, Christian Henrik; Helin, K.; Sehested, M.

    1998-01-01

    The E2F transcription factors are key targets for the retinoblastoma protein, pRB. By inactivation of E2Fs, pRB prevents progression to the S phase. To test proliferative functions of E2F, we generated transgenic mice expressing human E2F-1 and/or human DP-1. When the hydroxymethyl glutaryl...... involving increased apoptosis in the germinal epithelium. This effect was potentiated by simultaneous overexpression of DP-1. Testicular atrophy as a result of overexpression of E2F-1 and DP-1 is independent of functional p53, since p53-nullizygous transgenic mice overexpressing E2F-1 and DP-1 also suffered...

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

    International Nuclear Information System (INIS)

    Szybka, Malgorzata; Kordek, Radzislaw; Zakrzewska, Magdalena; Rieske, Piotr; Pasz-Walczak, Grazyna; Kulczycka-Wojdala, Dominika; Zawlik, Izabela; Stawski, Robert; Jesionek-Kupnicka, Dorota; Liberski, Pawel P

    2009-01-01

    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. 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. 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. 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

  15. p53 expression and mutation analysis of odontogenic cysts with and without dysplasia.

    Science.gov (United States)

    Cox, Darren P

    2012-01-01

    Overexpression of p53 protein is well described in odontogenic cystic lesions (OCLs), including those with epithelial dysplasia; however, most p53 antibodies stain both wild-type and mutated p53 protein and may not reflect genotype. Direct sequencing of the p53 gene has not identified mutations in OCLs with dysplasia. The purpose of this study was to determine the molecular basis of p53 expression in several types of OCLs with and without dysplasia. The study material comprised 13 OCLs: odontogenic keratocyst (n = 5), orthokeratinized odontogenic cyst (n = 5), dentigerous cyst (n = 2), lateral periodontal cyst (n = 1), and unspecified developmental odontogenic cyst (UDOC) (n = 1). Five of these had features of mild or moderate epithelial dysplasia. One intraosseous squamous cell carcinoma (SCC) that was believed to have arisen from an antecedent dysplastic orthokeratinized OC was also included. Immunohistochemistry was performed using the DO7 monoclonal antibody that recognizes wild-type and mutated p53. DNA was extracted from microdissected tissue for all samples and exons 4 to 8 of the p53 gene direct sequenced. In 4 of 5 OCLs with dysplasia there was strong nuclear staining of basal and suprabasal cells. In all cases without dysplasia, nuclear expression in basal cells was either negative or weak and was absent in suprabasal cell nuclei. A mutation in exon 6 of the p53 gene (E224D) was identified in both the dysplastic orthokeratinized OC and the subsequent intraosseous SCC. OCLs with features of dysplasia show increased expression of p53 protein that does not reflect p53 mutational status. One dysplastic OC shared the same p53 mutation with a subsequent intraosseous SCC, indicating that p53 mutation may be associated with malignant transformation in this case. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. ZNF307, a novel zinc finger gene suppresses p53 and p21 pathway

    International Nuclear Information System (INIS)

    Li Jing; Wang Yuequn; Fan Xiongwei; Mo Xiaoyang; Wang Zequn; Li Yongqing; Yin Zhaochu; Deng Yun; Luo Na; Zhu Chuanbing; Liu Mingyao; Ma Qian; Ocorr, Karen; Yuan Wuzhou; Wu Xiushan

    2007-01-01

    We have cloned a novel KRAB-related zinc finger gene, ZNF307, encoding a protein of 545 aa. ZNF307 is conserved across species in evolution and is differentially expressed in human adult and fetal tissues. The fusion protein of EGFP-ZNF307 localizes in the nucleus. Transcriptional activity assays show ZNF307 suppresses transcriptional activity of L8G5-luciferase. Overexpressing ZNF307 in different cell lines also inhibits the transcriptional activities of p53 and p21. Moreover, ZNF307 works by reducing the p53 protein level and p53 protein reduction is achieved by increasing transcription of MDM2 and EP300. ZNF307 might suppress p53-p21 pathway through activating MDM2 and EP300 expression and inducing p53 degradation

  17. p53 functions as a cell cycle control protein in osteosarcomas.

    Science.gov (United States)

    Diller, L; Kassel, J; Nelson, C E; Gryka, M A; Litwak, G; Gebhardt, M; Bressac, B; Ozturk, M; Baker, S J; Vogelstein, B

    1990-11-01

    Mutations in the p53 gene have been associated with a wide range of human tumors, including osteosarcomas. Although it has been shown that wild-type p53 can block the ability of E1a and ras to cotransform primary rodent cells, it is poorly understood why inactivation of the p53 gene is important for tumor formation. We show that overexpression of the gene encoding wild-type p53 blocks the growth of osteosarcoma cells. The growth arrest was determined to be due to an inability of the transfected cells to progress into S phase. This suggests that the role of the p53 gene as an antioncogene may be in controlling the cell cycle in a fashion analogous to the check-point control genes in Saccharomyces cerevisiae.

  18. p53 functions as a cell cycle control protein in osteosarcomas.

    Science.gov (United States)

    Diller, L; Kassel, J; Nelson, C E; Gryka, M A; Litwak, G; Gebhardt, M; Bressac, B; Ozturk, M; Baker, S J; Vogelstein, B

    1990-01-01

    Mutations in the p53 gene have been associated with a wide range of human tumors, including osteosarcomas. Although it has been shown that wild-type p53 can block the ability of E1a and ras to cotransform primary rodent cells, it is poorly understood why inactivation of the p53 gene is important for tumor formation. We show that overexpression of the gene encoding wild-type p53 blocks the growth of osteosarcoma cells. The growth arrest was determined to be due to an inability of the transfected cells to progress into S phase. This suggests that the role of the p53 gene as an antioncogene may be in controlling the cell cycle in a fashion analogous to the check-point control genes in Saccharomyces cerevisiae. Images PMID:2233717

  19. Cytotoxic T-lymphocyte clones, established by stimulation with the HLA-A2 binding p5365-73 wild type peptide loaded on dendritic cells In vitro, specifically recognize and lyse HLA-A2 tumour cells overexpressing the p53 protein

    DEFF Research Database (Denmark)

    Barfoed, Annette Malene; Petersen, T R; Kirkin, A F

    2000-01-01

    of recognizing p53 derived wild type (self) peptides. Furthermore, the capacity of R9V specific T cell clones to exert HLA restricted cytotoxicity, argues that the R9V peptide is naturally presented on certain cancer cells. This supports the view that p53 derived wild type peptides might serve as candidate......Mutations in the tumour suppressor gene p53 are among the most frequent genetic alterations in human malignancies, often associated with an accumulation of the p53 protein in the cytoplasm. We have generated a number of cytotoxic T lymphocyte (CTL) clones that specifically recognize the HLA-A*0201...

  20. High frequency of HIF-1 alpha overexpression in BRCA1 related breast cancer

    NARCIS (Netherlands)

    van der Groep, Petra; Bouter, Alwin; Menko, Fred H.; van der Wall, Elsken; van Diest, Paul J.

    2008-01-01

    Hypoxia is a hallmark of cancer. Hypoxia inducible factor-1 alpha (HIF-1 alpha) is the key regulator of the hypoxia response. HIF-1 alpha is overexpressed during sporadic breast carcinogenesis and correlated with poor prognosis. Little is known on the role of HIF-1 alpha in hereditary breast

  1. p53 Aggregates penetrate cells and induce the co-aggregation of intracellular p53.

    Directory of Open Access Journals (Sweden)

    Karolyn J Forget

    Full Text Available Prion diseases are unique pathologies in which the infectious particles are prions, a protein aggregate. The prion protein has many particular features, such as spontaneous aggregation, conformation transmission to other native PrP proteins and transmission from an individual to another. Protein aggregation is now frequently associated to many human diseases, for example Alzheimer's disease, Parkinson's disease or type 2 diabetes. A few proteins associated to these conformational diseases are part of a new category of proteins, called prionoids: proteins that share some, but not all, of the characteristics associated with prions. The p53 protein, a transcription factor that plays a major role in cancer, has recently been suggested to be a possible prionoid. The protein has been shown to accumulate in multiple cancer cell types, and its aggregation has also been reproduced in vitro by many independent groups. These observations suggest a role for p53 aggregates in cancer development. This study aims to test the «prion-like» features of p53. Our results show in vitro aggregation of the full length and N-terminally truncated protein (p53C, and penetration of these aggregates into cells. According to our findings, the aggregates enter cells using macropinocytosis, a non-specific pathway of entry. Lastly, we also show that once internalized by the cell, p53C aggregates can co-aggregate with endogenous p53 protein. Together, these findings suggest prion-like characteristics for p53 protein, based on the fact that p53 can spontaneously aggregate, these aggregates can penetrate cells and co-aggregate with cellular p53.

  2. p53 inactivation in chewing tobacco-induced oral cancers and leukoplakias from India.

    Science.gov (United States)

    Saranath, D; Tandle, A T; Teni, T R; Dedhia, P M; Borges, A M; Parikh, D; Sanghavi, V; Mehta, A R

    1999-05-01

    The inactivation of p53 tumour suppressor gene vis-á-vis point mutation, overexpression and degradation due to Human Papilloma virus (HPV) 16/18 infection, was examined in chewing tobacco-associated oral cancers and oral leukoplakias from India. The analysis of mutations was assessed by polymerase chain reaction (PCR) with single strand conformation polymorphism (PCR-SSCP) of exons 5-9 on DNA from 83 oral cancer cases, and the mutations confirmed by direct nucleotide sequencing of the PCR products. p53 protein expression was evaluated by immunohistochemical analysis on paraffin-embedded sections of 62 representative oral cancer biopsies and 22 leukoplakias, using p53-specific monoclonal antibody DO-7. The presence of HPV16/18 was detected in the 83 oral cancer cases by PCR analysis using HPV L1 consensus sequences, followed by Southern hybridization with type-specific oligonucleotide probes. Forty-six per cent (38/83) of oral cancer tumours showed p53 alterations, with 17% (14/83) showing point mutations, 37% (23/62) with overexpression and 25% (21/83) with presence of HPV16 wherein the E6 HPV16 protein degrades p53. HPV18 was not detected in any of the samples. Ninety-two per cent concordance was observed between missense point mutations and overexpression of p53 protein. A significant correlation was not observed between p53 alterations in oral cancer and clinico-pathological profile of the patients. Twenty-seven per cent (6/22) of oral leukoplakias showed p53 overexpression. The overall p53 alterations in oral cancer tissues and oral lesions are comparable to data from the oral cancers reported in the Western countries with smoking and alcohol-associated oral cancers, and suggest a critical role for p53 gene in a significant proportion of oral cancers from India. The overexpression of p53 protein in leukoplakias may serve as a valuable biomarker for identifying individuals at high risk of transformation to malignant phenotype.

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

    International Nuclear Information System (INIS)

    Jung, Ji-Eun; Kim, Tae-Kyung; Lee, Joong-Seob; Oh, Se-Yeong; Kwak, Sungwook; Jin, Xun; Sohn, Jin-Young; Song, Min-Keun; Sohn, Young-Woo; Lee, Soo-Yeon; Pian, Xumin; Lee, Jang-Bo; Chung, Yong Gu; Choi, Young Ki; You, Seungkwon; Kim, Hyunggee

    2005-01-01

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

  4. Distinct HIC1-SIRT1-p53 Loop Deregulation in Lung Squamous Carcinoma and Adenocarcinoma Patients

    Directory of Open Access Journals (Sweden)

    Ruo-Chia Tseng

    2009-08-01

    Full Text Available A HIC1-SIRT1-p53 circular loop in which hypermethylation in cancer 1 (HIC1 represses the transcription of SIRT1 that deacetylates and inactivates p53 thus leading to HIC1 inactivation has been identified in cell and animal models. However, the alteration and prognostic effects of HIC1-SIRT1-p53 circular loop have never been demonstrated in human cancer patients. We examine the HIC1-SIRT1-p53 alterations in 118 lung cancer patients to define their etiological roles in tumorigenesis. We found that patients with lung squamous cell carcinoma with low p53 acetylation and SIRT1 expression mostly showed low HIC1 expression, confirming deregulation of HIC1-SIRT1-p53 circular loop in the clinical model. Interestingly, the expression of deleted in breast cancer 1 (DBC1, which blocks the interaction between SIRT1 deacetylase and p53, led to acetylated p53 in patients with lung adenocarcinoma. However, epigenetic alteration of HIC1 promoter by posttranslational modifications of histones and promoter hypermethylation favoring the compacted chromatin production attenuated the transcriptional induction by acetylated p53. Importantly, lung cancer patients with altered HIC1-SIRT1-p53 circular regulation showed poor prognosis. Our data show the first valid clinical evidence of the deregulation of HIC1-SIRT1-p53 loop in lung tumorigenesis and prognosis. Distinct status of p53 acetylation/deacetylation and HIC1 alteration mechanism result from different SIRT1-DBC1 control and epigenetic alteration in lung squamous cell carcinoma and lung adenocarcinoma.

  5. Hypoxia-induced p53 modulates both apoptosis and radiosensitivity via AKT

    Science.gov (United States)

    Leszczynska, Katarzyna B.; Foskolou, Iosifina P.; Abraham, Aswin G.; Anbalagan, Selvakumar; Tellier, Céline; Haider, Syed; Span, Paul N.; O’Neill, Eric E.; Buffa, Francesca M.; Hammond, Ester M.

    2015-01-01

    Restoration of hypoxia-induced apoptosis in tumors harboring p53 mutations has been proposed as a potential therapeutic strategy; however, the transcriptional targets that mediate hypoxia-induced p53-dependent apoptosis remain elusive. Here, we demonstrated that hypoxia-induced p53-dependent apoptosis is reliant on the DNA-binding and transactivation domains of p53 but not on the acetylation sites K120 and K164, which, in contrast, are essential for DNA damage–induced, p53-dependent apoptosis. Evaluation of hypoxia-induced transcripts in multiple cell lines identified a group of genes that are hypoxia-inducible proapoptotic targets of p53, including inositol polyphosphate-5-phosphatase (INPP5D), pleckstrin domain–containing A3 (PHLDA3), sulfatase 2 (SULF2), B cell translocation gene 2 (BTG2), cytoplasmic FMR1-interacting protein 2 (CYFIP2), and KN motif and ankyrin repeat domains 3 (KANK3). These targets were also regulated by p53 in human cancers, including breast, brain, colorectal, kidney, bladder, and melanoma cancers. Downregulation of these hypoxia-inducible targets associated with poor prognosis, suggesting that hypoxia-induced apoptosis contributes to p53-mediated tumor suppression and treatment response. Induction of p53 targets, PHLDA3, and a specific INPP5D transcript mediated apoptosis in response to hypoxia through AKT inhibition. Moreover, pharmacological inhibition of AKT led to apoptosis in the hypoxic regions of p53-deficient tumors and consequently increased radiosensitivity. Together, these results identify mediators of hypoxia-induced p53-dependent apoptosis and suggest AKT inhibition may improve radiotherapy response in p53-deficient tumors. PMID:25961455

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

    Directory of Open Access Journals (Sweden)

    Zhang Xifeng

    2010-09-01

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

  7. Mutant p53 interactions with supercoiled DNA

    Czech Academy of Sciences Publication Activity Database

    Brázdová, Marie; Němcová, Kateřina; Činčárová, Lenka; Šebest, Peter; Pivoňková, Hana; Brázda, Václav; Fojta, Miroslav; Paleček, Emil

    2007-01-01

    Roč. 24, č. 6 (2007), s. 639-640 ISSN 0739-1102. [Alban 2007: The 15th Conversation . 19.06.2007-23.06.2007, Albany] R&D Projects: GA MŠk(CZ) 1K04119; GA ČR(CZ) GP204/06/P369; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : mutant p53 * supercoiled DNA * cancer Subject RIV: BO - Biophysics

  8. Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

    Science.gov (United States)

    Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

    1992-07-15

    Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-line mutant proteins observed in patients with Li-Fraumeni syndrome, second primary neoplasms, or familial breast cancer to block the growth of malignant cells and compared the structural properties of the mutant proteins to that of the wild-type protein. Six of seven missense mutations disrupted the growth inhibitory properties and structure of the wild-type protein. One germ-line mutation retained the features of the wild-type p53. Genetic analysis of the breast cancer family in which this mutation was observed indicated that this germ-line mutation was not associated with the development of cancer. These results demonstrate that germ-line p53 mutations observed in patients with Li-Fraumeni syndrome and with second malignancies have inactivated the p53 tumor suppressor gene. The inability of the germ-line p53 mutants to block the growth of malignant cells can explain why patients with these germ-line mutations have an increased risk for cancer. The observation of a functionally silent germ-line mutation indicates that, before associating a germ-line tumor suppressor gene mutation with cancer risk, it is prudent to consider its functional significance.

  9. Germ-line mutations of the p53 tumor suppressor gene in patients with high risk for cancer inactivate the p53 protein.

    Science.gov (United States)

    Frebourg, T; Kassel, J; Lam, K T; Gryka, M A; Barbier, N; Andersen, T I; Børresen, A L; Friend, S H

    1992-01-01

    Germ-line mutations in the p53 tumor suppressor gene have been observed in patients with Li-Fraumeni syndrome, brain tumors, second malignancies, and breast cancers. It is unclear whether all of these mutations have inactivated p53 and thereby provide an increased risk for cancer. Therefore, it is necessary to establish the biological significance of these germ-line mutations by the functional and structural analysis of the resulting mutant p53 proteins. We analyzed the ability of seven germ-line mutant proteins observed in patients with Li-Fraumeni syndrome, second primary neoplasms, or familial breast cancer to block the growth of malignant cells and compared the structural properties of the mutant proteins to that of the wild-type protein. Six of seven missense mutations disrupted the growth inhibitory properties and structure of the wild-type protein. One germ-line mutation retained the features of the wild-type p53. Genetic analysis of the breast cancer family in which this mutation was observed indicated that this germ-line mutation was not associated with the development of cancer. These results demonstrate that germ-line p53 mutations observed in patients with Li-Fraumeni syndrome and with second malignancies have inactivated the p53 tumor suppressor gene. The inability of the germ-line p53 mutants to block the growth of malignant cells can explain why patients with these germ-line mutations have an increased risk for cancer. The observation of a functionally silent germ-line mutation indicates that, before associating a germ-line tumor suppressor gene mutation with cancer risk, it is prudent to consider its functional significance. Images PMID:1631137

  10. Overexpression of Oct4 suppresses the metastatic potential of breast cancer cells via Rnd1 downregulation.

    Science.gov (United States)

    Shen, Long; Qin, Kunhua; Wang, Dekun; Zhang, Yan; Bai, Nan; Yang, Shengyong; Luo, Yunping; Xiang, Rong; Tan, Xiaoyue

    2014-11-01

    Although Oct4 is known as a critical transcription factor involved in maintaining "stemness", its role in tumor metastasis is still controversial. Herein, we overexpressed and silenced Oct4 expression in two breast cancer cell lines, MDA-MB-231 and 4T1, separately. Our data showed that ectopic overexpression of Oct4 suppressed cell migration and invasion in vitro and the formation of metastatic lung nodules in vivo. Conversely, Oct4 downregulation increased the metastatic potential of breast cancer cells both in vitro and in vivo. Furthermore, we identified Rnd1 as the downstream target of Oct4 by ribonucleic acid sequencing (RNA-seq) analysis, which was significantly downregulated upon Oct4 overexpression. Chromatin immunoprecipitation assays revealed the binding of Oct4 to the promoter region of Rnd1 by ectopic overexpression of Oct4. Dual luciferase assays indicated that Oct4 overexpression suppressed transcriptional activity of the Rnd1 promoter. Moreover, overexpression of Rnd1 partially rescued the inhibitory effects of Oct4 on the migration and invasion of breast cancer cells. Overexpression of Rnd1 counteracted the influence of Oct4 on the formation of cell adhesion and lamellipodia, which implied a potential underlying mechanism involving Rnd1. In addition, we also found that overexpression of Oct4 led to an elevation of E-cadherin expression, even in 4T1 cells that possess a relatively high basal level of E-cadherin. Rnd1 overexpression impaired the promoting effects of Oct4 on E-cadherin expression in MDA-MB-231 cells. These results suggest that Oct4 affects the metastatic potential of breast cancer cells through Rnd1-mediated effects that influence cell motility and E-cadherin expression. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Ara, N.; Atique, M.; Ahmed, S.; Bukhari, S. G. A.

    2014-01-01

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

  12. Vav3 oncogene activates estrogen receptor and its overexpression may be involved in human breast cancer

    International Nuclear Information System (INIS)

    Lee, Kiwon; Liu, Yin; Mo, Jun Qin; Zhang, Jinsong; Dong, Zhongyun; Lu, Shan

    2008-01-01

    Our previous study revealed that Vav3 oncogene is overexpressed in human prostate cancer, activates androgen receptor, and stimulates growth in prostate cancer cells. The current study is to determine a potential role of Vav3 oncogene in human breast cancer and impact on estrogen receptor a (ERα)-mediated signaling axis. Immunohistochemistry analysis was performed in 43 breast cancer specimens and western blot analysis was used for human breast cancer cell lines to determine the expression level of Vav3 protein. The impact of Vav3 on breast cancer cell growth was determined by siRNA knockdown of Vav3 expression. The role of Vav3 in ERα activation was examined in luciferase reporter assays. Deletion mutation analysis of Vav3 protein was performed to localize the functional domain involved in ERα activation. Finally, the interaction of Vav3 and ERα was assessed by GST pull-down analysis. We found that Vav3 was overexpressed in 81% of human breast cancer specimens, particularly in poorly differentiated lesions. Vav3 activated ERα partially via PI3K-Akt signaling and stimulated growth of breast cancer cells. Vav3 also potentiated EGF activity for cell growth and ERα activation in breast cancer cells. More interestingly, we found that Vav3 complexed with ERα. Consistent with its function for AR, the DH domain of Vav3 was essential for ERα activation. Vav3 oncogene is overexpressed in human breast cancer. Vav3 complexes with ERα and enhances ERα activity. These findings suggest that Vav3 overexpression may aberrantly enhance ERα-mediated signaling axis and play a role in breast cancer development and/or progression

  13. The miR-1000-p53 pathway regulates apoptosis and virus infection in shrimp.

    Science.gov (United States)

    Gong, Yi; Ju, Chenyu; Zhang, Xiaobo

    2015-10-01

    The p53 protein plays an important role in apoptosis which is involved in the immunity of animals. However, effects of the miRNA-mediated regulation of p53 expression on apoptosis and virus infection are not extensively investigated. To address this issue, the miRNA-mediated p53-dependent apoptotic pathway was explored in this study. The results indicated that p53 could regulate the apoptotic activity of Marsupenaeus japonicas shrimp and influence the infection of white spot syndrome virus (WSSV). The further data presented that miR-1000 could target the 3'-untranslated region (3'UTR) of p53 gene. The results of in vivo experiments showed that the miR-1000 overexpression led to significant decreases of shrimp apoptotic activity and the capacity of WSSV infection, while the miR-1000 silencing resulted in significant increases of apoptotic activity and virus infection, indicating that miR-1000 took great effects on apoptosis and virus infection by targeting p53. Therefore, our study revealed a novel mechanism that the miR-1000-p53 pathway regulated apoptosis and virus infection in shrimp. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Molecular Dynamic Simulation Insights into the Normal State and Restoration of p53 Function

    Directory of Open Access Journals (Sweden)

    Jianzhong Chen

    2012-08-01

    Full Text Available As a tumor suppressor protein, p53 plays a crucial role in the cell cycle and in cancer prevention. Almost 50 percent of all human malignant tumors are closely related to a deletion or mutation in p53. The activity of p53 is inhibited by over-active celluar antagonists, especially by the over-expression of the negative regulators MDM2 and MDMX. Protein-protein interactions, or post-translational modifications of the C-terminal negative regulatory domain of p53, also regulate its tumor suppressor activity. Restoration of p53 function through peptide and small molecular inhibitors has become a promising strategy for novel anti-cancer drug design and development. Molecular dynamics simulations have been extensively applied to investigate the conformation changes of p53 induced by protein-protein interactions and protein-ligand interactions, including peptide and small molecular inhibitors. This review focuses on the latest MD simulation research, to provide an overview of the current understanding of interactions between p53 and its partners at an atomic level.

  15. ARF and ATM/ATR cooperate in p53-mediated apoptosis upon oncogenic stress

    International Nuclear Information System (INIS)

    Pauklin, Siim; Kristjuhan, Arnold; Maimets, Toivo; Jaks, Viljar

    2005-01-01

    Induction of apoptosis is pivotal for eliminating cells with damaged DNA or deregulated proliferation. We show that tumor suppressor ARF and ATM/ATR kinase pathways cooperate in the induction of apoptosis in response to elevated expression of c-myc, β-catenin or human papilloma virus E7 oncogenes. Overexpression of oncogenes leads to the formation of phosphorylated H2AX foci, induction of Rad51 protein levels and ATM/ATR-dependent phosphorylation of p53. Inhibition of ATM/ATR kinases abolishes both induction of Rad51 and phosphorylation of p53, and remarkably reduces the level of apoptosis induced by co-expression of oncogenes and ARF. However, the induction of apoptosis is downregulated in p53-/- cells and does not depend on activities of ATM/ATR kinases, indicating that efficient induction of apoptosis by oncogene activation depends on coordinated action of ARF and ATM/ATR pathways in the regulation of p53

  16. Tumour suppressor protein p53 regulates the stress activated bilirubin oxidase cytochrome P450 2A6

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Hao, E-mail: hao.hu1@uqconnect.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Yu, Ting, E-mail: t.yu2@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Arpiainen, Satu, E-mail: Satu.Juhila@orion.fi [Institute of Biomedicine, Department of Pharmacology and Toxicology and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu (Finland); Lang, Matti A., E-mail: m.lang@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Hakkola, Jukka, E-mail: Jukka.hakkola@oulu.fi [Institute of Biomedicine, Department of Pharmacology and Toxicology and Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu (Finland); Abu-Bakar, A' edah, E-mail: a.abubakar@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia)

    2015-11-15

    Human cytochrome P450 (CYP) 2A6 enzyme has been proposed to play a role in cellular defence against chemical-induced oxidative stress. The encoding gene is regulated by various stress activated transcription factors. This paper demonstrates that p53 is a novel transcriptional regulator of the gene. Sequence analysis of the CYP2A6 promoter revealed six putative p53 binding sites in a 3 kb proximate promoter region. The site closest to transcription start site (TSS) is highly homologous with the p53 consensus sequence. Transfection with various stepwise deletions of CYP2A6-5′-Luc constructs – down to − 160 bp from the TSS – showed p53 responsiveness in p53 overexpressed C3A cells. However, a further deletion from − 160 to − 74 bp, including the putative p53 binding site, totally abolished the p53 responsiveness. Electrophoretic mobility shift assay with a probe containing the putative binding site showed specific binding of p53. A point mutation at the binding site abolished both the binding and responsiveness of the recombinant gene to p53. Up-regulation of the endogenous p53 with benzo[α]pyrene – a well-known p53 activator – increased the expression of the p53 responsive positive control and the CYP2A6-5′-Luc construct containing the intact p53 binding site but not the mutated CYP2A6-5′-Luc construct. Finally, inducibility of the native CYP2A6 gene by benzo[α]pyrene was demonstrated by dose-dependent increases in CYP2A6 mRNA and protein levels along with increased p53 levels in the nucleus. Collectively, the results indicate that p53 protein is a regulator of the CYP2A6 gene in C3A cells and further support the putative cytoprotective role of CYP2A6. - Highlights: • CYP2A6 is an immediate target gene of p53. • Six putative p53REs located on 3 kb proximate CYP2A6 promoter region. • The region − 160 bp from TSS is highly homologous with the p53 consensus sequence. • P53 specifically bind to the p53RE on the − 160 bp region. • HNF4

  17. Critical role of c-Jun overexpression in liver metastasis of human breast cancer xenograft model

    International Nuclear Information System (INIS)

    Zhang, Yan; Hu, Meiru; Shen, Beifen; Guo, Ning; Pu, Xiaoyun; Shi, Ming; Chen, Liyong; Song, Yuhua; Qian, Lu; Yuan, Guogang; Zhang, Hao; Yu, Ming

    2007-01-01

    c-Jun/AP-1 has been linked to invasive properties of aggressive breast cancer. Recently, it has been reported that overexpression of c-Jun in breast cancer cell line MCF-7 resulted in increased AP-1 activity, motility and invasiveness of the cells in vitro and tumor formation in nude mice. However, the role of c-Jun in metastasis of human breast cancer in vivo is currently unknown. To further investigate the direct involvement of c-Jun in tumorigenesis and metastasis, in the present study, the effects of c-Jun overexpression were studied in both in vitro and in nude mice. Ectopic overexpression of c-Jun promoted the growth of MCF-7 cells and resulted in a significant increase in the percentage of cells in S phase and increased motility and invasiveness. Introduction of c-Jun gene alone into weakly invasive MCF-7 cells resulted in the transfected cells capable of metastasizing to the nude mouse liver following tail vein injection. The present study confirms that overexpression of c-Jun contributes to a more invasive phenotype in MCF-7 cells. It indicates an interesting relationship between c-Jun expression and increased property of adhesion, migration and in vivo liver metastasis of MCF-7/c-Jun cells. The results provide further evidence that c-Jun is involved in the metastasis of breast cancer. The finding also opens an opportunity for development of anti-c-Jun strategies in breast cancer therapy

  18. Nuclear inclusion bodies of mutant and wild-type p53 in cancer: a hallmark of p53 inactivation and proteostasis remodelling 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; Delgado Blanco, Javier; 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

    2017-05-01

    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 nIB formation. This was most prominent for mutant p53, but could also be observed in wild-type p53 cell lines, for which nIB formation correlated with the loss of p53's transcriptional activity. Importantly, protein aggregation also fuelled the dysregulation of the proteostasis network in the tumour cell by inducing a hyperactivated, 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 showing tumours with p53-positive nIBs suffered from a poor clinical outcome, similar to those with loss of p53 expression, and tumour biopsies showed a differential proteostatic expression profile associated with p53-positive nIBs. p53-positive nIBs therefore highlight a malignant state of the tumour that results from the interplay between (1) the functional inactivation of p53 through mutation and/or aggregation, and (2) microenvironmental stress, a combination that catalyses proteostatic dysregulation. This study highlights several unexpected clinical, biological and therapeutically unexplored parallels between cancer and neurodegeneration. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2016 Pathological Society of Great

  19. Expression of Androgen Receptor Is Negatively Regulated By p53

    Directory of Open Access Journals (Sweden)

    Fatouma Alimirah

    2007-12-01

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

  20. Expression of p53, Bcl-2, VEGF, Ki67 and PCNA and prognostic significance in hepatocellular carcinoma.

    Science.gov (United States)

    Stroescu, Cezar; Dragnea, Adrian; Ivanov, Bogdan; Pechianu, Catalin; Herlea, Vlad; Sgarbura, Olivia; Popescu, Andra; Popescu, Irinel

    2008-12-01

    Hepatocellular carcinoma is one of the most common malignant tumors that carry a poor prognosis. To improve the long-term outlook for HCC, an accurate prognosis is important. To study the immunohistochemical expressions of p53, Ki67, Bcl-2, VEGF and PCNA and their potential role as prognostic factors in patients with radical resection of hepatocellular carcinoma. Forty-seven formalin-fixed paraffin-embedded tumor samples from patients with HCC receiving liver resection were investigated immunohistochemically for the expression of cellular proliferation markers PCNA, Ki67, p53, Bcl-2 and VEGF and their correlation with tumor characteristics and survival time after resection. p53 was expressed in a higher percentage (85.7 vs. 42.1%) in undifferentiated histological tumor grades (Edmondson Steiner G3/G4 vs. G1/G2). Patients with p53 accumulating tumors showed a worse survival than patients with p53 non-accumulating tumors (median 9.5 vs. 16.5 months). Over-expression of VEGF was found in 38.3% of all HCCs. VEGF expression was significantly correlated with p53 expression and recurrence rates. The results showed that the labeling index of PCNA and expression of p53 are correlated. The high labeling index of PCNA or over-expression of p53 resulted in high risk of tumor recurrence, more aggressive growth and poor survival. High labeling index of PCNA, p53 nuclear accumulation and VEGF high expression are associated with poor survival in patients with HCC.

  1. Wild type p53 transcriptionally represses the SALL2 transcription factor under genotoxic stress.

    Directory of Open Access Journals (Sweden)

    Carlos Farkas

    Full Text Available SALL2- a member of the Spalt gene family- is a poorly characterized transcription factor found deregulated in various cancers, which suggests it plays a role in the disease. We previously identified SALL2 as a novel interacting protein of neurotrophin receptors and showed that it plays a role in neuronal function, which does not necessarily explain why or how SALL2 is deregulated in cancer. Previous evidences indicate that SALL2 gene is regulated by the WT1 and AP4 transcription factors. Here, we identified SALL2 as a novel downstream target of the p53 tumor suppressor protein. Bioinformatic analysis of the SALL2 gene revealed several putative p53 half sites along the promoter region. Either overexpression of wild-type p53 or induction of the endogenous p53 by the genotoxic agent doxorubicin repressed SALL2 promoter activity in various cell lines. However R175H, R249S, and R248W p53 mutants, frequently found in the tumors of cancer patients, were unable to repress SALL2 promoter activity, suggesting that p53 specific binding to DNA is important for the regulation of SALL2. Electrophoretic mobility shift assay demonstrated binding of p53 to one of the identified p53 half sites in the Sall2 promoter, and chromatin immunoprecipitation analysis confirmed in vivo interaction of p53 with the promoter region of Sall2 containing this half site. Importantly, by using a p53ER (TAM knockin model expressing a variant of p53 that is completely dependent on 4-hydroxy-tamoxifen for its activity, we show that p53 activation diminished SALL2 RNA and protein levels during genotoxic cellular stress in primary mouse embryo fibroblasts (MEFs and radiosensitive tissues in vivo. Thus, our finding indicates that p53 represses SALL2 expression in a context-specific manner, adding knowledge to the understanding of SALL2 gene regulation, and to a potential mechanism for its deregulation in cancer.

  2. Imiquimod activates p53-dependent apoptosis in a human basal cell carcinoma cell line.

    Science.gov (United States)

    Huang, Shi-Wei; Chang, Shu-Hao; Mu, Szu-Wei; Jiang, Hsin-Yi; Wang, Sin-Ting; Kao, Jun-Kai; Huang, Jau-Ling; Wu, Chun-Ying; Chen, Yi-Ju; Shieh, Jeng-Jer

    2016-03-01

    The tumor suppressor p53 controls DNA repair, cell cycle, apoptosis, autophagy and numerous other cellular processes. Imiquimod (IMQ), a synthetic toll-like receptor (TLR) 7 ligand for the treatment of superficial basal cell carcinoma (BCC), eliminates cancer cells by activating cell-mediated immunity and directly inducing apoptosis and autophagy in cancer cells. To evaluate the role of p53 in IMQ-induced cell death in skin cancer cells. The expression, phosphorylation and subcellular localization of p53 were detected by real-time PCR, luciferase reporter assay, cycloheximide chase analysis, immunoblotting and immunocytochemistry. Using BCC/KMC1 cell line as a model, the upstream signaling of p53 activation was dissected by over-expression of TLR7/8, the addition of ROS scavenger, ATM/ATR inhibitors and pan-caspase inhibitor. The role of p53 in IMQ-induced apoptosis and autophagy was assessed by genetically silencing p53 and evaluated by a DNA content assay, immunoblotting, LC3 puncta detection and acridine orange staining. IMQ induced p53 mRNA expression and protein accumulation, increased Ser15 phosphorylation, promoted nuclear translocation and up-regulated its target genes in skin cancer cells in a TLR7/8-independent manner. In BCC/KMC1 cells, the induction of p53 by IMQ was achieved through increased ROS production to stimulate the ATM/ATR-Chk1/Chk2 axis but was not mediated by inducing DNA damage. The pharmacological inhibition of ATM/ATR significantly suppressed IMQ-induced p53 activation and apoptosis. Silencing of p53 significantly decreased the IMQ-induced caspase cascade activation and apoptosis but enhanced autophagy. Mutant p53 skin cancer cell lines were more resistant to IMQ-induced apoptosis than wildtype p53 skin cancer cell lines. IMQ induced ROS production to stimulate ATM/ATR pathways and contributed to p53-dependent apoptosis in a skin basal cell carcinoma cell line BCC/KMC1. Copyright © 2015 Japanese Society for Investigative Dermatology

  3. SV40 large T-p53 complex: evidence for the presence of two immunologically distinct forms of p53

    International Nuclear Information System (INIS)

    Milner, J.; Gamble, J.

    1985-01-01

    The transforming protein of SV40 is the large T antigen. Large T binds a cellular protein, p53, which is potentially oncogenic by virtue of its functional involvement in the control of cell proliferation. This raises the possibility that p53 may mediate, in part, the transforming function of SV40 large T. Two immunologically distinct forms of p53 have been identified in normal cells: the forms are cell-cycle dependent, one being restricted to nondividing cells (p53-Go) and the second to dividing cells (p53-G divided by). The authors have now dissociated and probed the multimeric complex of SV40 large T-p53 for the presence of immunologically distinct forms of p53. Here they present evidence for the presence of p53-Go and p53-G divided by complexed with SV40 large T

  4. Overexpressed Genes/ESTs and Characterization of Distinct Amplicons on 17823 in Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Ayse E. Erson

    2001-01-01

    Full Text Available 17823 is a frequent site of gene amplification in breast cancer. Several lines of evidence suggest the presence of multiple amplicons on 17823. To characterize distinct amplicons on 17823 and localize putative oncogenes, we screened genes and expressed sequence tags (ESTs in existing physical and radiation hybrid maps for amplification and overexpression in breast cancer cell lines by semiquantitative duplex PCR, semiquantitative duplex RT-PCR, Southern blot, Northern blot analyses. We identified two distinct amplicons on 17823, one including TBX2 and another proximal region including RPS6KB1 (PS6K and MUL. In addition to these previously reported overexpressed genes, we also identified amplification and overexpression of additional uncharacterized genes and ESTs, some of which suggest potential oncogenic activity. In conclusion, we have further defined two distinct regions of gene amplification and overexpression on 17823 with identification of new potential oncogene candidates. Based on the amplification and overexpression patterns of known and as of yet unrecognized genes on 17823, it is likely that some of these genes mapping to the discrete amplicons function as oncogenes and contribute to tumor progression in breast cancer cells.

  5. Functional promoter upstream p53 regulatory sequence of IGFBP3 that is silenced by tumor specific methylation

    International Nuclear Information System (INIS)

    Hanafusa, Tadashi; Shinji, Toshiyuki; Shiraha, Hidenori; Nouso, Kazuhiro; Iwasaki, Yoshiaki; Yumoto, Eichiro; Ono, Toshiro; Koide, Norio

    2005-01-01

    Insulin-like growth factor binding protein (IGFBP)-3 functions as a carrier of insulin-like growth factors (IGFs) in circulation and a mediator of the growth suppression signal in cells. There are two reported p53 regulatory regions in the IGFBP3 gene; one upstream of the promoter and one intronic. We previously reported a hot spot of promoter hypermethylation of IGFBP-3 in human hepatocellular carcinomas and derivative cell lines. As the hot spot locates at the putative upstream p53 consensus sequences, these p53 consensus sequences are really functional is a question to be answered. In this study, we examined the p53 consensus sequences upstream of the IGFBP-3 promoter for the p53 induced expression of IGFBP-3. Deletion, mutagenesis, and methylation constructs of IGFBP-3 promoter were assessed in the human hepatoblastoma cell line HepG2 for promoter activity. Deletions and mutations of these sequences completely abolished the expression of IGFBP-3 in the presence of p53 overexpression. In vitro methylation of these p53 consensus sequences also suppressed IGFBP-3 expression. In contrast, the expression of IGFBP-3 was not affected in the absence of p53 overexpression. Further, we observed by electrophoresis mobility shift assay that p53 binding to the promoter region was diminished when methylated. From these observations, we conclude that four out of eleven p53 consensus sequences upstream of the IGFBP-3 promoter are essential for the p53 induced expression of IGFBP-3, and hypermethylation of these sequences selectively suppresses p53 induced IGFBP-3 expression in HepG2 cells

  6. A novel radiation-induced p53 mutation is not implicated in radiation resistance via a dominant-negative effect.

    Directory of Open Access Journals (Sweden)

    Yunguang Sun

    Full Text Available Understanding the mutations that confer radiation resistance is crucial to developing mechanisms to subvert this resistance. Here we describe the creation of a radiation resistant cell line and characterization of a novel p53 mutation. Treatment with 20 Gy radiation was used to induce mutations in the H460 lung cancer cell line; radiation resistance was confirmed by clonogenic assay. Limited sequencing was performed on the resistant cells created and compared to the parent cell line, leading to the identification of a novel mutation (del at the end of the DNA binding domain of p53. Levels of p53, phospho-p53, p21, total caspase 3 and cleaved caspase 3 in radiation resistant cells and the radiation susceptible (parent line were compared, all of which were found to be similar. These patterns held true after analysis of p53 overexpression in H460 cells; however, H1299 cells transfected with mutant p53 did not express p21, whereas those given WT p53 produced a significant amount, as expected. A luciferase assay demonstrated the inability of mutant p53 to bind its consensus elements. An MTS assay using H460 and H1299 cells transfected with WT or mutant p53 showed that the novel mutation did not improve cell survival. In summary, functional characterization of a radiation-induced p53 mutation in the H460 lung cancer cell line does not implicate it in the development of radiation resistance.

  7. Mutant p53 protein localized in the cytoplasm inhibits autophagy.

    Science.gov (United States)

    Morselli, Eugenia; Tasdemir, Ezgi; Maiuri, Maria Chiara; Galluzzi, Lorenzo; Kepp, Oliver; Criollo, Alfredo; Vicencio, José Miguel; Soussi, Thierry; Kroemer, Guido

    2008-10-01

    The knockout, knockdown or chemical inhibition of p53 stimulates autophagy. Moreover, autophagy-inducing stimuli such as nutrient depletion, rapamycin or lithium cause the depletion of cytoplasmic p53, which in turn is required for the induction of autophagy. Here, we show that retransfection of p53(-/-) HCT 116 colon carcinoma cells with wild type p53 decreases autophagy down to baseline levels. Surprisingly, one third among a panel of 22 cancer-associated p53 single amino acid mutants also inhibited autophagy when transfected into p53(-/-) cells. Those variants of p53 that preferentially localize to the cytoplasm effectively repressed autophagy, whereas p53 mutants that display a prominently nuclear distribution failed to inhibit autophagy. The investigation of a series of deletion mutants revealed that removal of the DNA-binding domain from p53 fails to interfere with its role in the regulation of autophagy. Altogether, these results identify the cytoplasmic localization of p53 as the most important feature for p53-mediated autophagy inhibition. Moreover, the structural requirements for the two biological activities of extranuclear p53, namely induction of apoptosis and inhibition of autophagy, are manifestly different.

  8. p53 specific (auto)immunity in mice

    NARCIS (Netherlands)

    Lauwen, Marjolein Monique

    2008-01-01

    Self-tolerance to p53 is a major potential limitation for the activation of the endogenous T-cell repertoire. So far, p53 specific CD8+ and CD4+ T-cell immunity has been described in cancer patients and healthy individuals. However, the restrictions of tolerance on the recruitment of p53 specific T

  9. Restriction of human herpesvirus 6B replication by p53

    DEFF Research Database (Denmark)

    Øster, Bodil; Kofod-Olsen, Emil; Bundgaard, Bettina

    2008-01-01

    Human herpesvirus 6B (HHV-6B) induces significant accumulation of p53 in both the nucleus and cytoplasm during infection. Activation of p53 by DNA damage is known to induce either growth arrest or apoptosis; nevertheless, HHV-6B-infected cells are arrested in their cell cycle independently of p53...

  10. 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

  11. A Dual Role of P53 in Regulating Colistin-Induced Autophagy in PC-12 Cells

    Directory of Open Access Journals (Sweden)

    Ziyin Lu

    2017-10-01

    Full Text Available This study aimed to investigate the mechanism of p53 in regulating colistin-induced autophagy in PC-12 cells. Importantly, cells were treated with 125 μg/ml colistin for 12 and 24 h after transfection with p53 siRNA or recombinant plasmid. The hallmarks of autophagy and apoptosis were examined by real-time PCR and western blot, fluorescence/immunofluorescence microscopy, and electron microscopy. The results showed that silencing of p53 leads to down-regulation of Atg5 and beclin1 for 12 h while up-regulation at 24 h and up-regulation of p62 noted. The ratio of LC3-II/I and autophagic vacuoles were significantly increased at 24 h, but autophagy flux was blocked. The cleavage of caspase3 and PARP (poly ADP-ribose polymerase were enhanced, while PC-12-sip53 cells exposed to 3-MA showed down-regulation of apoptosis. By contrast, the expression of autophagy-related genes and protein reduced in p53 overexpressing cells following a time dependent manner. Meanwhile, there was an increase in the expression of activated caspase3 and PARP, condensed and fragmented nuclei were evident. Conclusively, the data supported that silencing of p53 promotes impaired autophagy, which acts as a pro-apoptotic induction factor in PC-12 cells treated with colistin for 24 h, and overexpression of p53 inhibits autophagy and accelerates apoptosis. Hence, it has been suggested that p53 could not act as a neuro-protective target in colistin-induced neurotoxicity.

  12. The prognostic significance of accumulation of p53 protein in stage III non-small cell lung cancer treated by radiotherapy

    International Nuclear Information System (INIS)

    Langendijk, J.A.; Thunnissen, F.B.J.M.; Lamers, R.J.S.; Jong, J.M.A. de; Velde, G.P.M. ten; Wouters, E.F.M.

    1995-01-01

    In the present study the prognostic significance of accumulation of nuclear p53 protein on survival and freedom from local progression was investigated. Formalin-fixed, paraffin-embedded sections obtained by bronchoscopy or mediastinoscopy were used to examine the expression of nuclear p53 protein using immunohistochemistry. In 37 cases (57%), overexpression of the p53 protein was detected. No relation was found between p53 expression and other pretreatment variables. Response to radiotherapy was found in 11 p53-negative cases (65%) versus 10 p53-positive cases (42%). Freedom from local progression was significantly better in the p53-negative cases as compared with the p53-positive cases. The p53-negative cases who responded to radiotherapy showed an excellent freedom from local progression rate after 2 years of 100%, whereas all p53-positive cases without response to radiotherapy showed local progression within 24 months. Overall survival between p53-negative and -positive cases did not differ, however the disease-specific survival was found to be worse in the p53-positive cases as compared to the negative cases (median survival 8.4 vs. 14.4 months (P < 0.05)). No correlation was found between p53 expression and the frequency of distant metastases. In conclusion, the results of this study suggest that p53 protein expression may be of prognostic value on freedom from local progression in non-small cell lung carcinoma

  13. Targeting GPR110 in HER2-Overexpressing Breast Cancers

    Science.gov (United States)

    2015-10-01

    34assay"using"the"transwell" inserts"with" (A)"or"without" (B)"matrigel" for"SKBR3" cells "transfected"with"nonAtarge1ng"( NT1 )"orŗ"independent"GPR110"siRNAs...HER2 drug resistant cells and in tumorigenic population using a broad panel of cell line models. We have successfully generated inducible lentiviral...plasmids with GPR110 cDNA and cell lines that inducibly overexpress GPR110. Generation of cell lines with lentiviral plasmids containing GPR110

  14. 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......-like elements was performed by luciferase reporter assays, qPCR, and poly(A) assays. Herein, we report the down regulation of a luciferase reporter fused to the p53 3'-UTR, when human CPE-binding protein 1 (hCPEB1) is overexpressed. This inhibition is partially rescued when hCPEB1fused to hGLD-2 [a human...... 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...

  15. Cyclophilin B induces chemoresistance by degrading wild type p53 via interaction with MDM2 in colorectal cancer.

    Science.gov (United States)

    Choi, Tae Gyu; Nguyen, Minh Nam; Kim, Jieun; Jo, Yong Hwa; Jang, Miran; Nguyen, Ngoc Ngo Yen; Yun, Hyeong Rok; Choe, Wonchae; Kang, Insug; Ha, Joohun; Tang, Dean G; Kim, Sung Soo

    2018-06-06

    Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Chemoresistance is a major problem for effective therapy in CRC. Here, we investigated the mechanism by which peptidylprolyl isomerase B (PPIB; cyclophilin B, CypB) regulates chemoresistance in CRC. We found that CypB is a novel wild type p53 (p53WT)-inducible gene but a negative regulator of p53WT in response to oxaliplatin treatment. Overexpression of CypB shortens the half-life of p53WT and inhibits oxaliplatin-induced apoptosis in CRC cells, whereas knockdown of CypB lengthens the half-life of p53WT and stimulates p53WT dependent apoptosis. CypB interacts directly with MDM2, and enhances MDM2-dependent p53WT ubiquitination and degradation. Furthermore, we firmly validated using bioinformatics analyses that overexpression of CypB is associated with poor prognosis in CRC progression and chemoresistance. Hence, we suggest a novel mechanism of chemoresistance caused by overexpressed CypB, which may help to develop new anti-cancer drugs. We also propose that CypB may be utilized as a predictive biomarker in CRC patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  16. 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.

    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,

  17. Immunohistochemical analysis of P53 protein in odontogenic cysts

    Science.gov (United States)

    Gaballah, Essam Taher M.A.; Tawfik, Mohamed A.

    2010-01-01

    The p53 is a well-known tumor suppressor gene, the mutations of which are closely related to the decreased differentiation of cells. Findings of studies on immunohistochemical P53 expression in odontogenic cysts are controversial. The present study was carried-out to investigate the immunohistochemical expression of P53 protein in odontogenic cysts. Thirty paraffin blocks of diagnosed odontogenic cysts were processed to determine the immunohistochemical expression of P53 protein. Nine of the 11 odontogenic keratocysts (81.8%) expressed P53, one of three dentigerous cyst cases expressed P53, while none of the 16 radicular cysts expressed P53 protein. The findings of the present work supported the reclassification of OKC as keratocystic odontogenic tumor. PMID:23960493

  18. Bcl-2 overexpression prevents 99mTc-MIBI uptake in breast cancer cell lines

    International Nuclear Information System (INIS)

    Aloj, Luigi; Zannetti, Antonella; Caraco, Corradina; Del Vecchio, Silvana; Salvatore, Marco

    2004-01-01

    We have previously shown a correlation between the absence of technetium-99m methoxyisobutylisonitrile ( 99m Tc-MIBI) uptake and overexpression of the anti-apoptotic protein Bcl-2 in human breast carcinoma. To establish a direct cause-effect relationship between Bcl-2 overexpression and reduced 99m Tc-MIBI uptake, MCF-7 and T47D breast cancer cell lines were stably transfected with the human Bcl-2 gene to increase intracellular protein levels and tested for 99m Tc-MIBI uptake. All clones overexpressing Bcl-2 showed a dramatic reduction of 99m Tc-MIBI uptake as compared with mock transfected control cells. Tracer uptake was promptly and partially restored by induction of apoptosis with staurosporine treatment. After 4.5 h of staurosporine treatment, a tenfold increase in 99m Tc-MIBI uptake was observed in treated as compared with untreated Bcl-2 overexpressing cells. Our findings provide a rational basis for the development of an in vivo test to detect Bcl-2 overexpression in human tumours. (orig.)

  19. Effects of clusterin over-expression on metastatic progression and therapy in breast cancer

    International Nuclear Information System (INIS)

    Flanagan, Louise; Whyte, Lorna; Chatterjee, Namita; Tenniswood, Martin

    2010-01-01

    Clusterin is a secreted glycoprotein that is upregulated in a variety of cell lines in response to stress, and enhances cell survival. A second nuclear isoform of clusterin that is associated with cell death has also been identified. The aim of this study was to determine the role(s) of the secretory isoform in breast tumor progression and metastasis. To investigate the role of secretory clusterin in the biology of breast cancer tumor growth and resistance to therapy we have engineered an MCF-7 cell line (MCF-7CLU) that over-expresses clusterin. We have measured the in vitro effects of clusterin over-expression on cell cycle, cell death, and sensitivity to TNFalpha and tamoxifen. Using an orthotopic model of breast cancer, we have also determined the effects of over-expression of clusterin on tumor growth and metastatic progression. In vitro, over-expression of secretory clusterin alters the cell cycle kinetics and decreases the rate of cell death, resulting in the enhancement of cell growth. Over-expression of secretory clusterin also blocks the TNFalpha-mediated induction of p21 and abrogates the cleavage of Bax to t-Bax, rendering the MCF-7CLU cells significantly more resistant to the cytokine than the parental cells. Orthotopic primary tumors derived from MCF-7CLU cells grow significantly more rapidly than tumors derived from parental MCF-7 cells and, unlike the parental cells, metastasize frequently to the lungs. These data suggest that secretory clusterin, which is frequently up-regulated in breast cancers by common therapies, including anti-estrogens, may play a significant role in tumor growth, metastatic progression and subsequent drug resistance in surviving cells

  20. Effects of clusterin over-expression on metastatic progression and therapy in breast cancer

    Directory of Open Access Journals (Sweden)

    Chatterjee Namita

    2010-03-01

    Full Text Available Abstract Background Clusterin is a secreted glycoprotein that is upregulated in a variety of cell lines in response to stress, and enhances cell survival. A second nuclear isoform of clusterin that is associated with cell death has also been identified. The aim of this study was to determine the role(s of the secretory isoform in breast tumor progression and metastasis. Methods To investigate the role of secretory clusterin in the biology of breast cancer tumor growth and resistance to therapy we have engineered an MCF-7 cell line (MCF-7CLU that over-expresses clusterin. We have measured the in vitro effects of clusterin over-expression on cell cycle, cell death, and sensitivity to TNFalpha and tamoxifen. Using an orthotopic model of breast cancer, we have also determined the effects of over-expression of clusterin on tumor growth and metastatic progression. Results In vitro, over-expression of secretory clusterin alters the cell cycle kinetics and decreases the rate of cell death, resulting in the enhancement of cell growth. Over-expression of secretory clusterin also blocks the TNFalpha-mediated induction of p21 and abrogates the cleavage of Bax to t-Bax, rendering the MCF-7CLU cells significantly more resistant to the cytokine than the parental cells. Orthotopic primary tumors derived from MCF-7CLU cells grow significantly more rapidly than tumors derived from parental MCF-7 cells and, unlike the parental cells, metastasize frequently to the lungs. Conclusions These data suggest that secretory clusterin, which is frequently up-regulated in breast cancers by common therapies, including anti-estrogens, may play a significant role in tumor growth, metastatic progression and subsequent drug resistance in surviving cells.

  1. The p53 codon 72 polymorphism and association to prostate cancer ...

    African Journals Online (AJOL)

    Jane

    2011-10-05

    Oct 5, 2011 ... the bones and lymph nodes. This is called metastatic prostate cancer. Many studies indicate that environ- mental and genetic factors such as p53 gene play a ... genotoxic stimulus, triggering the expression of several genes that affect DNA .... cervical cancer, breast cancer, colorectal and prostate cancer.

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

    Directory of Open Access Journals (Sweden)

    Marković Olivera

    2007-01-01

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

  3. Substrate Stiffness Influences Doxorubicin-Induced p53 Activation via ROCK2 Expression

    Directory of Open Access Journals (Sweden)

    Takahiro Ebata

    2017-01-01

    Full Text Available The physical properties of the extracellular matrix (ECM, such as stiffness, are involved in the determination of the characteristics of cancer cells, including chemotherapy sensitivity. Resistance to chemotherapy is often linked to dysfunction of tumor suppressor p53; however, it remains elusive whether the ECM microenvironment interferes with p53 activation in cancer cells. Here, we show that, in MCF-7 breast cancer cells, extracellular stiffness influences p53 activation induced by the antitumor drug doxorubicin. Cell growth inhibition by doxorubicin was increased in response to ECM rigidity in a p53-dependent manner. The expression of Rho-associated coiled coil-containing protein kinase (ROCK 2, which induces the activation of myosin II, was significantly higher when cells were cultured on stiffer ECM substrates. Knockdown of ROCK2 expression or pharmacological inhibition of ROCK decreased doxorubicin-induced p53 activation. Our results suggest that a soft ECM causes downregulation of ROCK2 expression, which drives resistance to chemotherapy by repressing p53 activation.

  4. Prognostic and predictive values of EGFR overexpression and EGFR copy number alteration in HER2-positive breast cancer.

    Science.gov (United States)

    Lee, H J; Seo, A N; Kim, E J; Jang, M H; Kim, Y J; Kim, J H; Kim, S-W; Ryu, H S; Park, I A; Im, S-A; Gong, G; Jung, K H; Kim, H J; Park, S Y

    2015-01-06

    Epidermal growth factor receptor (EGFR) is overexpressed in a subset of human epidermal growth factor receptor 2 (HER2)-positive breast cancers, and coexpression of HER2 and EGFR has been reported to be associated with poor clinical outcome. Moreover, interaction between HER2 and EGFR has been suggested to be a possible basis for trastuzumab resistance. We analysed the clinical significance of EGFR overexpression and EGFR gene copy number alterations in 242 HER2-positive primary breast cancers. In addition, we examined the correlations between EGFR overexpression, trastuzumab response and clinical outcome in 447 primary, and 112 metastatic HER2-positive breast cancer patients treated by trastuzumab. Of the 242 primary cases, the level of EGFR overexpression was 2+ in 12.7% and 3+ in 11.8%. High EGFR gene copy number was detected in 10.3%. Epidermal growth factor receptor overexpression was associated with hormone receptor negativity and high Ki-67 proliferation index. In survival analyses, EGFR overexpression, but not high EGFR copy number, was associated with poor disease-free survival in all patients, and in the subgroup not receiving adjuvant trastuzumab. In 447 HER2-positive primary breast cancer patients treated with adjuvant trastuzumab, EGFR overexpression was also an independent poor prognostic factor. However, EGFR overexpression was not associated with trastuzumab response, progression-free survival or overall survival in the metastatic setting. Epidermal growth factor receptor overexpression, but not high EGFR copy number, is a poor prognostic factor in HER2-positive primary breast cancer. Epidermal growth factor receptor overexpression is a predictive factor for trastuzumab response in HER2-positive primary breast cancer, but not in metastatic breast cancer.

  5. Mitofusin-2 is a novel direct target of p53

    International Nuclear Information System (INIS)

    Wang, Weilin; Cheng, Xiaofei; Lu, Jianju; Wei, Jianfeng; Fu, Guanghou; Zhu, Feng; Jia, Changku; Zhou, Lin; Xie, Haiyang; Zheng, Shusen

    2010-01-01

    Research highlights: → Mfn2 is a novel target gene of p53. → Mfn2 mRNA and protein levels can be up-regulated in a p53-dependent manner. → Mfn2 promoter activity can be elevated by the p53 protein. → P53 protein binds the Mfn2 promoter directly both in vitro and in vivo. -- Abstract: The tumor suppressor p53 modulates transcription of a number of target genes involved in cell cycle arrest, apoptosis, DNA repair, and other important cellular responses. Mitofusin-2 (Mfn2) is a novel suppressor of cell proliferation that may also exert apoptotic effects via the mitochondrial apoptotic pathway. Through bioinformatics analysis, we identified a p53 binding site in the Mfn2 promoter. Consistent with this, we showed that the p53 protein binds the Mfn2 promoter directly both in vitro and in vivo. Additionally, we found that Mfn2 mRNA and protein levels are up-regulated in a p53-dependent manner. Furthermore, luciferase assays revealed that the activity of the wild-type Mfn2 promoter, but not a mutated version of the promoter, was up-regulated by p53. These results indicate that Mfn2 is a novel p53-inducible target gene, which provides insight into the regulation of Mfn2 and its associated activities in the inhibition of cell proliferation, promotion of apoptosis, and modulation of tumor suppression.

  6. Combining Oncolytic Virotherapy with p53 Tumor Suppressor Gene Therapy

    Directory of Open Access Journals (Sweden)

    Christian Bressy

    2017-06-01

    Full Text Available Oncolytic virus (OV therapy utilizes replication-competent viruses to kill cancer cells, leaving non-malignant cells unharmed. With the first U.S. Food and Drug Administration-approved OV, dozens of clinical trials ongoing, and an abundance of translational research in the field, OV therapy is poised to be one of the leading treatments for cancer. A number of recombinant OVs expressing a transgene for p53 (TP53 or another p53 family member (TP63 or TP73 were engineered with the goal of generating more potent OVs that function synergistically with host immunity and/or other therapies to reduce or eliminate tumor burden. Such transgenes have proven effective at improving OV therapies, and basic research has shown mechanisms of p53-mediated enhancement of OV therapy, provided optimized p53 transgenes, explored drug-OV combinational treatments, and challenged canonical roles for p53 in virus-host interactions and tumor suppression. This review summarizes studies combining p53 gene therapy with replication-competent OV therapy, reviews preclinical and clinical studies with replication-deficient gene therapy vectors expressing p53 transgene, examines how wild-type p53 and p53 modifications affect OV replication and anti-tumor effects of OV therapy, and explores future directions for rational design of OV therapy combined with p53 gene therapy.

  7. [Punish or cherish: p53, metabolism and tumor suppression].

    Science.gov (United States)

    Albagli, Olivier

    2015-10-01

    The p53 gene is essential for tumor suppression, but how it does so remains unclear. Upon genotoxic or oncogenic stresses, increased p53 activity induces transient cell cycle arrest, senescence or apoptosis, the three cornerstones of the so-called triumvirate. Accordingly, it has long been thought that p53 suppresses tumorigenesis by somehow counteracting cell proliferation or survival. However, several recently described genetically modified mice indicate that p53 can suppress tumorigenesis without triggering these three responses. Rather, as an important mechanism for tumor suppression, these mutant mice point to the ability of p53 to prevent the Warburg effect, that is to dampen glycolysis and foster mitochondrial respiration. Interestingly, these metabolic functions of p53 rely, in part, on its "unstressed" (basal) expression, a feature shared by its mechanistically linked anti-oxydant function. Together, these "conservative" activities of p53 may prevent tumor initiation by promoting and maintaining a normal oxidative metabolism and hence underly the "daily" tumor suppression by p53 in most cells. Conversely, destructive activities elicited by high p53 levels and leading to senescence or apoptosis provide a shield against partially or overtly transformed cells. This last situation, although relatively infrequent throughout life, is usual in experimental settings, which could explain the disproportionally high number of data implicating the triumvirate in tumor suppression by p53. © 2015 médecine/sciences – Inserm.

  8. Targeting the p53 Pathway in Ewing Sarcoma

    Science.gov (United States)

    Neilsen, Paul M.; Pishas, Kathleen I.; Callen, David F.; Thomas, David M.

    2011-01-01

    The p53 tumour suppressor plays a pivotal role in the prevention of oncogenic transformation. Cancers frequently evade the potent antitumour surveillance mechanisms of p53 through mutation of the TP53 gene, with approximately 50% of all human malignancies expressing dysfunctional, mutated p53 proteins. Interestingly, genetic lesions in the TP53 gene are only observed in 10% of Ewing Sarcomas, with the majority of these sarcomas expressing a functional wild-type p53. In addition, the p53 downstream signaling pathways and DNA-damage cell cycle checkpoints remain functionally intact in these sarcomas. This paper summarizes recent insights into the functional capabilities and regulation of p53 in Ewing Sarcoma, with a particular focus on the cross-talk between p53 and the EWS-FLI1 gene rearrangement frequently associated with this disease. The development of several activators of p53 is discussed, with recent evidence demonstrating the potential of small molecule p53 activators as a promising systemic therapeutic approach for the treatment of Ewing Sarcomas with wild-type p53. PMID:21197471

  9. Interplay between PTB and miR-1285 at the p53 3'UTR modulates the levels of p53 and its isoform Δ40p53α.

    Science.gov (United States)

    Katoch, Aanchal; George, Biju; Iyyappan, Amrutha; Khan, Debjit; Das, Saumitra

    2017-09-29

    p53 and its translational isoform Δ40p53 are involved in many important cellular functions like cell cycle, cell proliferation, differentiation and metabolism. Expression of both the isoforms can be regulated at different steps. In this study, we explored the role of 3'UTR in regulating the expression of these two translational isoforms. We report that the trans acting factor, Polypyrimidine Tract Binding protein (PTB), also interacts specifically with 3'UTR of p53 mRNA and positively regulates expression of p53 isoforms. Our results suggest that there is interplay between miRNAs and PTB at the 3'UTR under normal and stress conditions like DNA damage. Interestingly, PTB showed some overlapping binding regions in the p53 3'UTR with miR-1285. In fact, knockdown of miR-1285 as well as expression of p53 3'UTR with mutated miR-1285 binding sites resulted in enhanced association of PTB with the 3'UTR, which provides mechanistic insights of this interplay. Taken together, the results provide a plausible molecular basis of how the interplay between miRNAs and the PTB protein at the 3'UTR can play pivotal role in fine tuning the expression of the two p53 isoforms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Synthesis and evaluation of modified chalcone based p53 stabilizing agents

    KAUST Repository

    Iftikhar, Sunniya

    2017-07-15

    Tumor suppressor protein p53 induces cell cycle arrest and apoptotic cell death in response to various cellular stresses thereby preventing cancer development. Activation and stabilization of p53 through small organic molecules is, therefore, an attractive approach for the treatment of cancers retaining wild-type p53. In this context, a series of nineteen chalcones with various substitution patterns of functional groups including chloro, fluoro, methoxy, nitro, benzyloxy, 4-methyl benzyloxy was prepared using Claisen-Schmidt condensation. The compounds were characterized using NMR, HRMS, IR and melting points. Evaluation of synthesized compounds against human colorectal (HCT116) and breast (Cal-51) cancer cell lines revealed potent antiproliferative activities. Nine compounds displayed GI50 values in the low micromolar to submicromolar range; for example (E)-1-phenyl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (SSE14108) showed GI50 of 0.473 ± 0.043 µM against HCT116 cells. Further analysis of these compounds revealed that (E)-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one (SSE14105) and (E)-3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one (SSE14106) caused rapid (4 and 8-hour post-treatment) accumulation of p53 in HCT116 cells similar to its induction by positive control, Nutlin-3. Such activities were absent in 3-(4-methoxyphenyl)propiophenone (SSE14106H2) demonstrating the importance of conjugated ketone for antiproliferative and p53 stabilizing activity of the chalcones. We further evaluated p53 levels in the presence of cycloheximide (CHX) and the results showed that the p53 stabilization was regulated at post-translational level through blockage of its degradation. These chalcones can, therefore, act as fragment leads for further structure optimization to obtain more potent p53 stabilizing agents with enhanced anti-proliferative activities.

  11. Synthesis and evaluation of modified chalcone based p53 stabilizing agents

    KAUST Repository

    Iftikhar, Sunniya; Khan, Sardraz; Bilal, Aishah; Manzoor, Safia; Abdullah, Muhammad; Emwas, Abdul-Hamid M.; Sioud, Salim; Gao, Xin; Chotana, Ghayoor Abbas; Faisal, Amir; Saleem, Rahman Shah Zaib

    2017-01-01

    Tumor suppressor protein p53 induces cell cycle arrest and apoptotic cell death in response to various cellular stresses thereby preventing cancer development. Activation and stabilization of p53 through small organic molecules is, therefore, an attractive approach for the treatment of cancers retaining wild-type p53. In this context, a series of nineteen chalcones with various substitution patterns of functional groups including chloro, fluoro, methoxy, nitro, benzyloxy, 4-methyl benzyloxy was prepared using Claisen-Schmidt condensation. The compounds were characterized using NMR, HRMS, IR and melting points. Evaluation of synthesized compounds against human colorectal (HCT116) and breast (Cal-51) cancer cell lines revealed potent antiproliferative activities. Nine compounds displayed GI50 values in the low micromolar to submicromolar range; for example (E)-1-phenyl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (SSE14108) showed GI50 of 0.473 ± 0.043 µM against HCT116 cells. Further analysis of these compounds revealed that (E)-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one (SSE14105) and (E)-3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one (SSE14106) caused rapid (4 and 8-hour post-treatment) accumulation of p53 in HCT116 cells similar to its induction by positive control, Nutlin-3. Such activities were absent in 3-(4-methoxyphenyl)propiophenone (SSE14106H2) demonstrating the importance of conjugated ketone for antiproliferative and p53 stabilizing activity of the chalcones. We further evaluated p53 levels in the presence of cycloheximide (CHX) and the results showed that the p53 stabilization was regulated at post-translational level through blockage of its degradation. These chalcones can, therefore, act as fragment leads for further structure optimization to obtain more potent p53 stabilizing agents with enhanced anti-proliferative activities.

  12. Che-1 gene silencing induces osteosarcoma cell apoptosis by inhibiting mutant p53 expression

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ming; Wang, Dan, E-mail: danwangwdd@163.com; Li, Ning

    2016-04-22

    The transcriptional cofactor Che-1 is an RNA polymerase II (Pol II) which is involved in tumorigenesis, such as breast cancer and multiple myeloma. Che-1 can also regulate mutant p53 expression, which plays roles in many types of cancer. In this study, we aimed to investigate the effects and specific mechanism of Che-1 in the regulation of osteosarcoma (OS) cell growth. We found that Che-1 is highly expressed in several kinds of OS cells compared with osteoblast hFOB1.19 cells. MTT and flow cytometry assays showed that Che-1 depletion by siRNA markedly suppressed MG-63 and U2OS cell proliferation and promoted apoptosis. The chromatin immunoprecipitation (ChIP) assay verified the presence of Che-1 on the p53 promoter in MG-63 and U2OS cells carrying mutant p53. Further studies showed that Che-1 depletion inhibited mutant p53 expression. Notably, our study showed that the loss of Che-1 inhibits proliferation and promotes apoptosis in MG-63 cells by decreasing the level of mutant p53. Therefore, these findings open the possibility that silencing of Che-1 will have therapeutic benefit in OS. - Highlights: • Che-1 is highly expressed in several kinds of OS cells. • Che-1 depletion suppressed MG-63 and U2OS cell growth. • Che-1 is existed in the p53 promoter in MG-63 and U2OS cells. • Che-1 depletion inhibited mutant p53 expression. • Che-1 depletion inhibits cell growth by decreasing the level of mutant p53.

  13. Gelsolin negatively regulates the activity of tumor suppressor p53 through their physical interaction in hepatocarcinoma HepG2 cells

    International Nuclear Information System (INIS)

    An, Joo-Hee; Kim, Jung-Woong; Jang, Sang-Min; Kim, Chul-Hong; Kang, Eun-Jin; Choi, Kyung-Hee

    2011-01-01

    Highlights: → The actin binding protein Gelsolin (GSN) interacts with transcription factor p53. → GSN interacts with transactivation- and DNA binding domains of p53. → GSN represses transactivity of p53 via inhibition of nuclear translocation of p53. → GSN inhibits the p53-mediated apoptosis in hepatocarcinoma HepG2 cells. -- Abstract: As a transcription factor, p53 modulates several cellular responses including cell-cycle control, apoptosis, and differentiation. In this study, we have shown that an actin regulatory protein, gelsolin (GSN), can physically interact with p53. The nuclear localization of p53 is inhibited by GSN overexpression in hepatocarcinoma HepG2 cells. Additionally, we demonstrate that GSN negatively regulates p53-dependent transcriptional activity of a reporter construct, driven by the p21-promoter. Furthermore, p53-mediated apoptosis was repressed in GSN-transfected HepG2 cells. Taken together, these results suggest that GSN binds to p53 and this interaction leads to the inhibition of p53-induced apoptosis by anchoring of p53 in the cytoplasm in HepG2 cells.

  14. Elevated expression of ribosomal protein genes L37, RPP-1, and S2 in the presence of mutant p53.

    Science.gov (United States)

    Loging, W T; Reisman, D

    1999-11-01

    The wild-type p53 protein is a DNA-binding transcription factor that activates genes such as p21, MDM2, GADD45, and Bax that are required for the regulation of cell cycle progression or apoptosis in response to DNA damage. Mutant forms of p53, which are transforming oncogenes and are expressed at high levels in tumor cells, generally have a reduced binding affinity for the consensus DNA sequence. Interestingly, some p53 mutants that are no longer effective at binding to the consensus DNA sequence and transactivating promoters containing this target site have acquired the ability to transform cells in culture, in part through their ability to transactivate promoters of a number of genes that are not targets of the wild-type protein. Certain p53 mutants are therefore considered to be gain-of-function mutants and appear to be promoting proliferation or transforming cells through their ability to alter the expression of novel sets of genes. Our goal is to identify genes that have altered expression in the presence of a specific mutant p53 (Arg to Trp mutation at codon 248) protein. Through examining differential gene expression in cells devoid of p53 expression and in cells that express high levels of mutant p53 protein, we have identified three ribosomal protein genes that have elevated expression in response to mutant p53. Consistent with these findings, the overexpression of a number of ribosomal protein genes in human tumors and evidence for their contribution to oncogenic transformation have been reported previously, although the mechanism leading to this overexpression has remained elusive. We show results that indicate that expression of these specific ribosomal protein genes is increased in the presence of the R248W p53 mutant, which provides a mechanism for their overexpression in human tumors.

  15. Prognostic implications of molecular and immunohistochemical profiles of the Rb and p53 cell cycle regulatory pathways in primary non-small cell lung carcinoma.

    LENUS (Irish Health Repository)

    Burke, Louise

    2012-02-03

    PURPOSE: Many studies have highlighted the aberrant expression and prognostic significance of individual proteins in either the Rb (particularly cyclin D1, p16INK4A, and pRb) or the p53 (p53 and p21Waf1) pathways in non-small cell lung cancer. We hypothesize that cumulative abnormalities within each and between these pathways would have significant prognostic potential regarding survival. EXPERIMENTAL DESIGN: Our study population consisted of 106 consecutive surgically resected cases of predominantly early-stage non-small cell lung cancer from the National Cancer Institute-Mayo Clinic series, and assessment of proteins involved both immunohistochemical (cyclin D1, p21Waf1, pRb, p16INK4A, and p53) and mutational analysis (p53) in relationship to staging and survival. RESULTS: Cyclin D1 overexpression was noted in 48% of the tumors, p16INK4A negative in 53%, pRb negative in 17%, p53 immunopositive in 50%, p53 mutation frequency in 48%, and p21(Waf1) overexpression in 47%, none with prognostic significance. Cyclin D1 overexpression in pRb-negative tumors revealed a significantly worse prognosis with a mean survival of 2.3 years (P = 0.004). A simultaneous p53 mutation dramatically reduced the mean survival time to 0.9 years (P = 0.007). Cyclin D1 overexpression with either a p53 mutation or a p53 overexpression was also associated with a significantly poorer prognosis (P = 0.0033 and 0.0063, respectively). CONCLUSIONS: Some cumulative abnormalities in the Rb and p53 pathways (e.g., cyclin D1 overexpression and p53 mutations) significantly cooperate to predict a poor prognosis; however, the complexity of the cell cycle protein interaction in any given tumor warrants caution in interpreting survival results when specific protein abnormalities are taken in isolation.

  16. A negative regulation loop of long noncoding RNA HOTAIR and p53 in non-small-cell lung cancer

    Directory of Open Access Journals (Sweden)

    Zhai N

    2016-09-01

    Full Text Available Nailiang Zhai,1 Yongfu Xia,1 Rui Yin,2 Jinping Liu,3 Fuquan Gao1 1Department of Respiratory Medicine, Affiliated Hospital of Binzhou Medical University, 2Department of Respiratory Medicine, People’s Hospital of Binzhou City, 3Department of Pharmacology, Binzhou Medical University, Binzhou, Shandong, People’s Republic of China Abstract: Non-small-cell lung cancer (NSCLC is one of the leading causes of cancer-related death worldwide, and the 5-year survival rate is still low despite advances in diagnosis and therapeutics. A long noncoding RNA (lncRNA HOX antisense intergenic RNA (HOTAIR has been revealed to play important roles in NSCLC carcinogenesis but the detailed mechanisms are still unclear. In the current study, we aimed to investigate the regulation between the lncRNA HOTAIR and p53 in the NSCLC patient samples and cell lines. Our results showed that HOTAIR expression was significantly higher in the cancer tissues than that in the adjacent normal tissue, and was negatively correlated with p53 functionality rather than expression. When p53 was overexpressed in A549 cells, the lncRNA HOTAIR expression was downregulated, and the cell proliferation rate and cell invasion capacity decreased as a consequence. We identified two binding sites of p53 on the promoter region of HOTAIR, where the p53 protein would bind to and suppress the HOTAIR mRNA transcription. Inversely, overexpression of lncRNA HOTAIR inhibited the expression of p53 in A549 cells. Mechanistic studies revealed that HOTAIR modified the promoter of p53 and enhanced histone H3 lysine 27 trimethylation (H3K27me3. These studies identified a specific negative regulation loop of lncRNA HOTAIR and p53 in NSCLC cells, which revealed a new understanding of tumorigenesis in p53 dysfunction NSCLC cells. Keywords: NSCLC, LncRNA HOTAIR, p53, negative loop

  17. Segmentation of HER2 protein overexpression in immunohistochemically stained breast cancer images using Support Vector Machines

    Science.gov (United States)

    Pezoa, Raquel; Salinas, Luis; Torres, Claudio; Härtel, Steffen; Maureira-Fredes, Cristián; Arce, Paola

    2016-10-01

    Breast cancer is one of the most common cancers in women worldwide. Patient therapy is widely supported by analysis of immunohistochemically (IHC) stained tissue sections. In particular, the analysis of HER2 overexpression by immunohistochemistry helps to determine when patients are suitable to HER2-targeted treatment. Computational HER2 overexpression analysis is still an open problem and a challenging task principally because of the variability of immunohistochemistry tissue samples and the subjectivity of the specialists to assess the samples. In addition, the immunohistochemistry process can produce diverse artifacts that difficult the HER2 overexpression assessment. In this paper we study the segmentation of HER2 overexpression in IHC stained breast cancer tissue images using a support vector machine (SVM) classifier. We asses the SVM performance using diverse color and texture pixel-level features including the RGB, CMYK, HSV, CIE L*a*b* color spaces, color deconvolution filter and Haralick features. We measure classification performance for three datasets containing a total of 153 IHC images that were previously labeled by a pathologist.

  18. P53-dependent upregulation of neutral sphingomyelinase-2: role in doxorubicin-induced growth arrest.

    Science.gov (United States)

    Shamseddine, A A; Clarke, C J; Carroll, B; Airola, M V; Mohammed, S; Rella, A; Obeid, L M; Hannun, Y A

    2015-10-29

    Neutral sphingomyelinase-2 (nSMase2) is a ceramide-generating enzyme that has been implicated in growth arrest, apoptosis and exosome secretion. Although previous studies have reported transcriptional upregulation of nSMase2 in response to daunorubicin, through Sp1 and Sp3 transcription factors, the role of the DNA damage pathway in regulating nSMase2 remains unclear. In this study, we show that doxorubicin induces a dose-dependent induction of nSMase2 mRNA and protein with concomitant increases in nSMase activity and ceramide levels. Upregulation of nSMase2 was dependent on ATR, Chk1 and p53, thus placing it downstream of the DNA damage pathway. Moreover, overexpression of p53 was sufficient to transcriptionally induce nSMase2, without the need for DNA damage. DNA-binding mutants as well as acetylation mutants of p53 were unable to induce nSMase2, suggesting a role of nSMase2 in growth arrest. Moreover, knockdown of nSMase2 prevented doxorubicin-induced growth arrest. Finally, p53-induced nSMase2 upregulation appears to occur via a novel transcription start site upstream of exon 3. These results identify nSMase2 as a novel p53 target gene, regulated by the DNA damage pathway to induce cell growth arrest.

  19. The 5S RNP couples p53 homeostasis to ribosome biogenesis and nucleolar stress.

    Science.gov (United States)

    Sloan, Katherine E; Bohnsack, Markus T; Watkins, Nicholas J

    2013-10-17

    Several proto-oncogenes and tumor suppressors regulate the production of ribosomes. Ribosome biogenesis is a major consumer of cellular energy, and defects result in p53 activation via repression of mouse double minute 2 (MDM2) homolog by the ribosomal proteins RPL5 and RPL11. Here, we report that RPL5 and RPL11 regulate p53 from the context of a ribosomal subcomplex, the 5S ribonucleoprotein particle (RNP). We provide evidence that the third component of this complex, the 5S rRNA, is critical for p53 regulation. In addition, we show that the 5S RNP is essential for the activation of p53 by p14(ARF), a protein that is activated by oncogene overexpression. Our data show that the abundance of the 5S RNP, and therefore p53 levels, is determined by factors regulating 5S complex formation and ribosome integration, including the tumor suppressor PICT1. The 5S RNP therefore emerges as the critical coordinator of signaling pathways that couple cell proliferation with ribosome production. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Family matters: sibling rivalry and bonding between p53 and p63 in cancer.

    Science.gov (United States)

    Romano, Rose-Anne; Sinha, Satrajit

    2014-04-01

    The p53 family (p53, p63 and p73) is intimately linked with an overwhelming number of cellular processes during normal physiological as well as pathological conditions including cancer. The fact that these proteins are expressed in myriad isoforms, each with unique biochemical properties and distinct effects on tumorigenesis, complicates their study. A case in point is Squamous Cell Carcinoma (SCC) where p53 is often mutated and the ΔNp63 isoform is overexpressed. Given that p53 and p63 can hetero-dimerize, bind to quite similar DNA elements and share common co-factors, any alterations in their individual expression levels, activity and/or mutation can severely disrupt the family equilibrium. The burgeoning genomics data sets and new additions to the experimental toolbox are offering crucial insights into the complex role of the p53 family in SCC, but more mechanistic studies are needed. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Battle Against Cancer: An Everlasting Saga of p53

    Directory of Open Access Journals (Sweden)

    Qian Hao

    2014-12-01

    Full Text Available Cancer is one of the most life-threatening diseases characterized by uncontrolled growth and spread of malignant cells. The tumor suppressor p53 is the master regulator of tumor cell growth and proliferation. In response to various stress signals, p53 can be activated and transcriptionally induces a myriad of target genes, including both protein-encoding and non-coding genes, controlling cell cycle progression, DNA repair, senescence, apoptosis, autophagy and metabolism of tumor cells. However, around 50% of human cancers harbor mutant p53 and, in the majority of the remaining cancers, p53 is inactivated through multiple mechanisms. Herein, we review the recent progress in understanding the molecular basis of p53 signaling, particularly the newly identified ribosomal stress—p53 pathway, and the development of chemotherapeutics via activating wild-type p53 or restoring mutant p53 functions in cancer. A full understanding of p53 regulation will aid the development of effective cancer treatments.

  2. Targeting p53 by small molecules in hematological malignancies

    OpenAIRE

    Saha, Manujendra N; Qiu, Lugui; Chang, Hong

    2013-01-01

    p53 is a powerful tumor suppressor and is an attractive cancer therapeutic target. A breakthrough in cancer research came from the discovery of the drugs which are capable of reactivating p53 function. Most anti-cancer agents, from traditional chemo- and radiation therapies to more recently developed non-peptide small molecules exert their effects by enhancing the anti-proliferative activities of p53. Small molecules such as nutlin, RITA, and PRIMA-1 that can activate p53 have shown their ant...

  3. The nucleolus directly regulates p53 export and degradation.

    Science.gov (United States)

    Boyd, Mark T; Vlatkovic, Nikolina; Rubbi, Carlos P

    2011-09-05

    The correlation between stress-induced nucleolar disruption and abrogation of p53 degradation is evident after a wide variety of cellular stresses. This link may be caused by steps in p53 regulation occurring in nucleoli, as suggested by some biochemical evidence. Alternatively, nucleolar disruption also causes redistribution of nucleolar proteins, potentially altering their interactions with p53 and/or MDM2. This raises the fundamental question of whether the nucleolus controls p53 directly, i.e., as a site where p53 regulatory processes occur, or indirectly, i.e., by determining the cellular localization of p53/MDM2-interacting factors. In this work, transport experiments based on heterokaryons, photobleaching, and micronucleation demonstrate that p53 regulatory events are directly regulated by nucleoli and are dependent on intact nucleolar structure and function. Subcellular fractionation and nucleolar isolation revealed a distribution of ubiquitylated p53 that supports these findings. In addition, our results indicate that p53 is exported by two pathways: one stress sensitive and one stress insensitive, the latter being regulated by activities present in the nucleolus.

  4. Overexpression of peroxiredoxin I and thioredoxin1 in human breast carcinoma

    Directory of Open Access Journals (Sweden)

    Kim Il-Han

    2009-06-01

    Full Text Available Abstract Background Peroxiredoxins (Prxs are a novel group of peroxidases containing high antioxidant efficiency. The mammalian Prx family has six distinct members (Prx I-VI in various subcellular locations, including peroxisomes and mitochondria, places where oxidative stress is most evident. The function of Prx I in particular has been implicated in regulating cell proliferation, differentiation, and apoptosis. Since thioredoxin1 (Trx1 as an electron donor is functionally associated with Prx I, we investigated levels of expression of both Prx I and Trx1. Methods We investigated levels of expression of both Prx I and Trx1 in breast cancer by real-time polymerase chain reaction (RT-PCR and Western blot. Results Levels of messenger RNA (mRNA for both Prx I and Trx1 in normal human breast tissue were very low compared to other major human tissues, whereas their levels in breast cancer exceeded that in other solid cancers (colon, kidney, liver, lung, ovary, prostate, and thyroid. Among members of the Prx family (Prx I-VI and Trx family (Trx1, Trx2, Prx I and Trx1 were preferentially induced in breast cancer. Moreover, the expression of each was associated with progress of breast cancer and correlated with each other. Western blot analysis of different and paired breast tissues revealed consistent and preferential expression of Prx I and Trx1 protein in breast cancer tissue. Conclusion Prx I and Trx1 are overexpressed in human breast carcinoma and the expression levels are associated with tumor grade. The striking induction of Prx I and Trx1 in breast cancer may enable their use as breast cancer markers.

  5. A Small Ras-like protein Ray/Rab1c modulates the p53-regulating activity of PRPK

    International Nuclear Information System (INIS)

    Abe, Yasuhito; Takeuchi, Takashi; Imai, Yoshinori; Murase, Ryuichi; Kamei, Yoshiaki; Fujibuchi, Taketsugu; Matsumoto, Suguru; Ueda, Norifumi; Ogasawara, Masahito; Shigemoto, Kazuhiro; Kito, Katsumi

    2006-01-01

    PRPK phosphorylates serine-15 residue of p53 and enhances transcriptional activity. PRPK possesses a bipartite nuclear localization signal and localizes in nucleus when over-expressed in cells. However, intrinsic PRPK localizes mainly in the cytosol in situ. While studying the mechanisms in the distribution of intrinsic PRPK, we identified a PRPK binding protein, an ubiquitously expressed Small Ras-like GTPase, Rab1c, also named Ray or Rab35. The over-expressed Ray was distributed in the nucleus, cytosol, and cell membrane. Both Ray wild type and GTP-restrictively binding mutant Ray-Q67L, but not guanine nucleotide unstable binding mutant Ray-N120I, partially distributed the over-expressed PRPK to the cytosol and also suppressed the PRPK-induced p53-transcriptional activity profoundly. A Small Ras-like GTPase protein Ray was thus indicated to modulate p53 transcriptional activity of PRPK

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

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhihong; Zhang, Yuxia [Departments of Medicine and Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84132 (United States); Wang, Li, E-mail: l.wang@hsc.utah.edu [Departments of Medicine and Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84132 (United States)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Mdm2 enhances HNF4{alpha} activation of the ApoCIII promoter via interaction with HNF4{alpha}. Black-Right-Pointing-Pointer p53 antagonizes the effect of Mdm2 activation of the ApoCIII promoter. Black-Right-Pointing-Pointer SHP strengthens p53 inhibition but abolishes Mdm2 activation of the ApoCIII promoter. Black-Right-Pointing-Pointer Mdm2 alters the enrichment of HNF4{alpha}, p53 and SHP to the ApoCIII promoter. -- Abstract: We examined the effect of Mdm2 on regulation of the ApoCIII promoter and its cross-talk with p53 and nuclear receptor SHP. Overexpression of Mdm2 markedly enhanced ApoCIII promoter activity by HNF4{alpha}. A direct association of Mdm2 protein with the HNF4{alpha} protein was observed by co-immunoprecipitation. Ectopic expression of p53 decreased HNF4{alpha} activation of the ApoCIII promoter and antagonized the effect of Mdm2. Co-expression of SHP further strengthened p53 inhibition and abolished Mdm2 activation of the ApoCIII promoter. Mdm2 inhibited p53-mediated enrichment of HNF4{alpha} to the ApoCIII promoter while simultaneously reducing p53 binding and increasing recruitment of SHP to the ApoCIII promoter. The results from this study implicate a potentially important function of Mdm2 in regulation of lipoprotein metabolism.

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

    International Nuclear Information System (INIS)

    Yang, Zhihong; Zhang, Yuxia; Wang, Li

    2012-01-01

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

  8. Frequent alteration of MDM2 and p53 in the molecular progression of recurring non-Hodgkin's lymphoma

    DEFF Research Database (Denmark)

    Møller, Michael Boe; Nielsen, O; Pedersen, Niels Tinggaard

    2002-01-01

    -Hodgkin's lymphoma. METHODS AND RESULTS: We have analysed sequential biopsies from 42 non-Hodgkin's lymphoma patients immunohistochemically for p53 alterations (based on p53 and p21Waf1 expression), as well as for expression of MDM2, p27Kip1 and cyclin D3. Relapse of follicle centre lymphoma was associated with p53...... alterations as 5/6 (83%) follicle centre lymphomas with normal p53 at diagnosis showed p53 alterations at relapse. Of these cases, three showed transformation to diffuse large B-cell lymphoma. p53 alteration was also associated with relapse of de novo diffuse large B-cell lymphoma and T-cell non......-Hodgkin's lymphoma, as 2/5 (40%) diffuse large B-cell lymphomas and 3/9 (33%) T-cell non-Hodgkin's lymphomas with normal p53 at diagnosis showed p53 alterations at relapse. No indolent non-Hodgkin's lymphoma case showed MDM2 over-expression at diagnosis, whereas 4/5 (80%) transformed diffuse large B-cell lymphomas...

  9. Enhancement of radiosensitivity of recombinant Ad-p53 gene on human lung adenocarcinoma cell with different p53 status

    International Nuclear Information System (INIS)

    Pang Dequan; Wang Peiguo; Wang Ping; Zhang Weiming

    2008-01-01

    Objective: To investigate the enhancement of radiosensitivity of recombinant Ad-p53 gene on human lung adenocarcinoma cell lines(A549 and GLC-82) with different p53 status in vitro. Methods: Two human lung adenocarcinoma cell lines of A549 and GLC-82 were examined on their difference in p53 status with immunohistochemistry stain and PCR-SSCP technique. Expand Ad-wtp53 was transfected into tumor cells. Clonogenic assays were performed to evaluate the inhibition effect on cell growth and the degree of sensitization to irradiation. Apoptosis and cell cycle changes were determined using the flow cytometry assay. Results: The A549 cell line presented positive P53 expression while GLC-82 negative. GLC-82 bore mutant p53 on the exon 7. The wtp53 gene could be efficiently expressed in the two cell lines and greatly inhibit the cell growth. Its efficiency didn't depend on the intrinsic p53 genetic status. After irradiation, its function of inducing G 1 arrest and apoptosis on GLC-82 cell line was much stronger than the A549 cell line. In both the A549 and GLC-82 cell lines, the combination of Ad-p53 plus radiation resulted in more apoptosis than the others. There was no significant difference between two groups. Conclusions: Ad-p53 can depress the tumor growth and enhance the radiosensitivity of human lung adenocarcinoma cells. And this effect is independent of endogenous p53 status. (authors)

  10. FRA-1 protein overexpression is a feature of hyperplastic and neoplastic breast disorders

    International Nuclear Information System (INIS)

    Chiappetta, Gennaro; Pierantoni, Giovanna Maria; Fusco, Alfredo; Ferraro, Angelo; Botti, Gerardo; Monaco, Mario; Pasquinelli, Rosa; Vuttariello, Emilia; Arnaldi, Liliane; Di Bonito, Maurizio; D'Aiuto, Giuseppe

    2007-01-01

    Fos-related antigen 1 (FRA-1) is an immediate early gene encoding a member of AP-1 family of transcription factors involved in cell proliferation, differentiation, apoptosis, and other biological processes. fra-1 gene overexpression has an important role in the process of cellular transformation, and our previous studies suggest FRA-1 protein detection as a useful tool for the diagnosis of thyroid neoplasias. Here we investigate the expression of the FRA-1 protein in benign and malignant breast tissues by immunohistochemistry, Western blot, RT-PCR and qPCR analysis, to evaluate its possible help in the diagnosis and prognosis of breast neoplastic diseases. We investigate the expression of the FRA-1 protein in 70 breast carcinomas and 30 benign breast diseases by immunohistochemistry, Western blot, RT-PCR and qPCR analysis. FRA-1 protein was present in all of the carcinoma samples with an intense staining in the nucleus. Positive staining was also found in most of fibroadenomas, but in this case the staining was present both in the nucleus and cytoplasm, and the number of positive cells was lower than in carcinomas. Similar results were obtained from the analysis of breast hyperplasias, with no differences in FRA-1 expression level between typical and atypical breast lesions; however the FRA-1 protein localization is mainly nuclear in the atypical hyperplasias. In situ breast carcinomas showed a pattern of FRA-1 protein expression very similar to that observed in atypical hyperplasias. Conversely, no FRA-1 protein was detectable in 6 normal breast tissue samples used as controls. RT-PCR and qPCR analysis confirmed these results. Similar results were obtained analysing FRA-1 expression in fine needle aspiration biopsy (FNAB) samples. The data shown here suggest that FRA-1 expression, including its intracellular localization, may be considered a useful marker for hyperplastic and neoplastic proliferative breast disorders

  11. Narrowband image and the p53 protein immunoexpression in patients with ulcerative colitis and dysplasia

    International Nuclear Information System (INIS)

    Chao González, Lissette

    2012-01-01

    Patients with pancolitis and long-standing ulcerative colitis are at increased risk of developing colorectal cancer, so it is advisable to colonoscopic surveillance. The objective of this study was to identify the endoscopic visualization system of imaging with narrowband and overexpression of the p53 protein as procedures useful for the research of Dysplasia in patients with ulcerative colitis and pancolitis, of eight or more years of evolution. A prospective, descriptive study was performed on 50 patients. The Fisher exact probability test was used for the statistical study and of square Chi, with a level of significance α = 0.05. Shown with narrow-band image increases the likelihood of finding suggestive areas of Dysplasia, reduces the amount of biopsy and gets a higher proportion of diagnoses of Dysplasia in fewer samples (70.4%). The overexpression of the p53 protein was associated with the presence of dysplasia (80.0%) p < 0.001 and is immunoexpress in samples with a high degree of severity of dysplasia and the low grade. Concluded that imaging with narrowband system and overexpression of the p53 protein are procedures useful for the research of Dysplasia in these patients. (author)

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

    Science.gov (United States)

    Michaelis, M; Rothweiler, F; Agha, B; Barth, S; Voges, Y; Löschmann, N; von Deimling, A; Breitling, R; Doerr, H Wilhelm; Rödel, F; Speidel, D; Cinatl, J

    2012-04-05

    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, also disrupts the p53/Mdm2 interaction. All of the 11 UKF-NB-3 sub-lines adapted to RITA that we established retained functional wild-type p53 although RITA induced a substantial p53 response. Moreover, all RITA-adapted cell lines remained sensitive to nutlin-3, whereas only five out of 10 nutlin-3-adapted cell lines retained their sensitivity to RITA. In addition, repeated adaptation of the RITA-adapted sub-line UKF-NB-3(r)RITA(10 μM) to nutlin-3 resulted in p53 mutations. The RITA-adapted UKF-NB-3 sub-lines displayed no or less pronounced resistance to vincristine, cisplatin, and irradiation than nutlin-3-adapted UKF-NB-3 sub-lines. Furthermore, adaptation to RITA was associated with fewer changes at the expression level of antiapoptotic factors than observed with adaptation to nutlin-3. Transcriptomic analyses indicated the RITA-adapted sub-lines to be more similar at the gene expression level to the parental UKF-NB-3 cells than nutlin-3-adapted UKF-NB-3 sub-lines, which correlates with the observed chemotherapy and irradiation sensitivity phenotypes. In conclusion, RITA-adapted cells retain functional p53, remain sensitive to nutlin-3, and display a less pronounced resistance phenotype than nutlin-3-adapted cells.

  13. Exploring a minimal two-component p53 model

    International Nuclear Information System (INIS)

    Sun, Tingzhe; Zhu, Feng; Shen, Pingping; Yuan, Ruoshi; Xu, Wei

    2010-01-01

    The tumor suppressor p53 coordinates many attributes of cellular processes via interlocked feedback loops. To understand the biological implications of feedback loops in a p53 system, a two-component model which encompasses essential feedback loops was constructed and further explored. Diverse bifurcation properties, such as bistability and oscillation, emerge by manipulating the feedback strength. The p53-mediated MDM2 induction dictates the bifurcation patterns. We first identified irradiation dichotomy in p53 models and further proposed that bistability and oscillation can behave in a coordinated manner. Further sensitivity analysis revealed that p53 basal production and MDM2-mediated p53 degradation, which are central to cellular control, are most sensitive processes. Also, we identified that the much more significant variations in amplitude of p53 pulses observed in experiments can be derived from overall amplitude parameter sensitivity. The combined approach with bifurcation analysis, stochastic simulation and sampling-based sensitivity analysis not only gives crucial insights into the dynamics of the p53 system, but also creates a fertile ground for understanding the regulatory patterns of other biological networks

  14. p53 downregulates the Fanconi anaemia DNA repair pathway.

    Science.gov (United States)

    Jaber, Sara; Toufektchan, Eléonore; Lejour, Vincent; Bardot, Boris; Toledo, Franck

    2016-04-01

    Germline mutations affecting telomere maintenance or DNA repair may, respectively, cause dyskeratosis congenita or Fanconi anaemia, two clinically related bone marrow failure syndromes. Mice expressing p53(Δ31), a mutant p53 lacking the C terminus, model dyskeratosis congenita. Accordingly, the increased p53 activity in p53(Δ31/Δ31) fibroblasts correlated with a decreased expression of 4 genes implicated in telomere syndromes. Here we show that these cells exhibit decreased mRNA levels for additional genes contributing to telomere metabolism, but also, surprisingly, for 12 genes mutated in Fanconi anaemia. Furthermore, p53(Δ31/Δ31) fibroblasts exhibit a reduced capacity to repair DNA interstrand crosslinks, a typical feature of Fanconi anaemia cells. Importantly, the p53-dependent downregulation of Fanc genes is largely conserved in human cells. Defective DNA repair is known to activate p53, but our results indicate that, conversely, an increased p53 activity may attenuate the Fanconi anaemia DNA repair pathway, defining a positive regulatory feedback loop.

  15. The genetic alteration of p53 in esophageal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jae Il; Baik, Hee Jong; Kim, Chang Min; Kim, Mi Hee [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1996-01-01

    Genetic alterations in the p53 gene have been detected in various human malignancies, and its alterations inactive the function of p53 as a tumor suppressor. Point mutation and gene deletion are the main mechanisms of p53 inactivation. To determine the incidence of genetic alteration of p53 and their clinical implications in Korean patients of esophageal cancer, we investigated p53 alterations in 26 esophageal cancer tissues paired with its normal tissue by Southern blot analysis, PCR-SSCP, and direct sequencing. Allelic loss of chromosome 17p occurred in 12 out of 21 informative cases(57%) by Southern blot analysis, and 16 cases showed mobility shift in PCR-SSCP, so overall incidence of p53 gene alterations was 77%(20/26). The mutations detected was randomly dispersed over exon4-8 and was frequently G-T transversion and C:T transitions. Three identical mutations were clustered at codon 213 suggested the same etiologic agents in this cases. The p53 gene alterations play a significant role in the development of esophageal cancers, however, no relationship between p53 mutation and clinical data was detected so far. 9 refs. (Author).

  16. Chronology of p53 protein accumulation in gastric carcinogenesis

    NARCIS (Netherlands)

    Craanen, M. E.; Blok, P.; Dekker, W.; Offerhaus, G. J.; Tytgat, G. N.

    1995-01-01

    p53 Protein accumulation in early gastric carcinoma was studied in relation to the histological type (Lauren classification) and the type of growth pattern, including the chronology of p53 protein accumulation during carcinogenesis. Forty five, paraffin embedded gastrectomy specimens from early

  17. p53 tumor suppressor gene: significance in neoplasia - a review

    International Nuclear Information System (INIS)

    Alam, J.M.

    2000-01-01

    p53 is a tumor suppressor gene located on chromosome 17p13.1. Its function includes cell cycle control and apoptosis. Loss of p53 function, either due to decreased level or genetic transformation, is associated with loss of cell cycle control, decrease, apoptosis and genomic modification, such mutation of p53 gene is now assessed and the indicator of neoplasia of cancer of several organs and cell types, p53 has demonstrated to have critical role in defining various progressive stages of neoplasia, therapeutic strategies and clinical application. The present review briefly describes function of p53 in addition to its diagnostic and prognostic significance in detecting several types of neoplasia. (author)

  18. Biological and genetic properties of the p53 null preneoplastic mammary epithelium

    Science.gov (United States)

    Medina, Daniel; Kittrell, Frances S.; Shepard, Anne; Stephens, L. Clifton; Jiang, Cheng; Lu, Junxuan; Allred, D. Craig; McCarthy, Maureen; Ullrich, Robert L.

    2002-01-01

    The absence of the tumor suppressor gene p53 confers an increased tumorigenic risk for mammary epithelial cells. In this report, we describe the biological and genetic properties of the p53 null preneoplastic mouse mammary epithelium in a p53 wild-type environment. Mammary epithelium from p53 null mice was transplanted serially into the cleared mammary fat pads of p53 wild-type BALB/c female to develop stable outgrowth lines. The outgrowth lines were transplanted for 10 generations. The outgrowths were ductal in morphology and progressed through ductal hyperplasia and ductal carcinoma in situ before invasive cancer. The preneoplastic outgrowth lines were immortal and exhibited activated telomerase activity. They are estrogen and progesterone receptor-positive, and aneuploid, and had various levels of tumorigenic potential. The biological and genetic properties of these lines are distinct from those found in most hyperplastic alveolar outgrowth lines, the form of mammary preneoplasia occurring in most traditional models of murine mammary tumorigenesis. These results indicate that the preneoplastic cell populations found in this genetically engineered model are similar in biological properties to a subset of precurser lesions found in human breast cancer and provide a unique model to identify secondary events critical for tumorigenicity and invasiveness.

  19. 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.

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

    International Nuclear Information System (INIS)

    Cappadone, C.; Stefanelli, C.; Malucelli, E.; Zini, M.; Onofrillo, C.; Locatelli, A.; Rambaldi, M.; Sargenti, A.; Merolle, L.; Farruggia, G.; Graziadio, A.; Montanaro, L.; Iotti, S.

    2015-01-01

    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.

  1. Expression of Egr1 and p53 in human carotid plaques and apoptosis induced by 7-oxysterol or p53.

    Science.gov (United States)

    Miah, Sayem; Zadeh, Shahram Nour Mohammad; Yuan, Xi-Ming; Li, Wei

    2013-07-01

    Egr-1 and p53 are involved in pathology of both atherosclerosis and cancer. However, it is unknown whether p53 and Egr1 are interactively involved in apoptosis in atherosclerosis. We found that in human carotid plaques, the expression of p53 was inversely correlated with Egr1. In U937 cells, 7β-hydroxycholesterol and 7-ketocholesterol induced production of reactive oxygen species (ROS), transient up-regulation of Egr1 followed by late induction of p53 and apoptosis. Cells with nuclear fragmentation induced by 7-oxysterol or p53 showed increased levels of p53, but decreased levels of Egr1. In conclusion, ROS induced by 7-oxysterols may function as an early initiator of Egr1 expression. The late induced p53 by 7-oxysterols contributes to apoptotic cell death and is linked to the reduction of Egr1 levels, which resembles the differential expression of p53 and Egr1 in human atheroma progression. Copyright © 2012 Elsevier GmbH. All rights reserved.

  2. Fluoxetine protects against IL-1β-induced neuronal apoptosis via downregulation of p53.

    Science.gov (United States)

    Shan, Han; Bian, Yaqi; Shu, Zhaoma; Zhang, Linxia; Zhu, Jialei; Ding, Jianhua; Lu, Ming; Xiao, Ming; Hu, Gang

    2016-08-01

    Fluoxetine, a selective serotonin reuptake inhibitor, exerts neuroprotective effects in a variety of neurological diseases including stroke, but the underlying mechanism remains obscure. In the present study, we addressed the molecular events in fluoxetine against ischemia/reperfusion-induced acute neuronal injury and inflammation-induced neuronal apoptosis. We showed that treatment of fluoxetine (40 mg/kg, i.p.) with twice injections at 1 h and 12 h after transient middle cerebral artery occlusion (tMCAO) respectively alleviated neurological deficits and neuronal apoptosis in a mouse ischemic stroke model, accompanied by inhibiting interleukin-1β (IL-1β), Bax and p53 expression and upregulating anti-apoptotic protein Bcl-2 level. We next mimicked neuroinflammation in ischemic stroke with IL-1β in primary cultured cortical neurons and found that pretreatment with fluoxetine (1 μM) prevented IL-1β-induced neuronal apoptosis and upregulation of p53 expression. Furthermore, we demonstrated that p53 overexpression in N2a cell line abolished the anti-apoptotic effect of fluoxetine, indicating that p53 downregulation is required for the protective role of fluoxetine in IL-1β-induced neuronal apoptosis. Fluoxetine downregulating p53 expression could be mimicked by SB203580, a specific inhibitor of p38, but blocked by anisomycin, a p38 activator. Collectively, our findings have revealed that fluoxetine protects against IL-1β-induced neuronal apoptosis via p38-p53 dependent pathway, which give us an insight into the potential of fluoxetine in terms of opening up novel therapeutic avenues for neurological diseases including stroke. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. p53 and the pathogenesis of skin cancer

    International Nuclear Information System (INIS)

    Benjamin, Cara L.; Ananthaswamy, Honnavara N.

    2007-01-01

    The p53 tumor suppressor gene and gene product are among the most diverse and complex molecules involved in cellular functions. Genetic alterations within the p53 gene have been shown to have a direct correlation with cancer development and have been shown to occur in nearly 50% of all cancers. p53 mutations are particularly common in skin cancers and UV irradiation has been shown to be a primary cause of specific 'signature' mutations that can result in oncogenic transformation. There are certain 'hot-spots' in the p53 gene where mutations are commonly found that result in a mutated dipyrimidine site. This review discusses the role of p53 from normal function and its dysfunction in pre-cancerous lesions and non-melanoma skin cancers. Additionally, special situations are explored, such as Li-Fraumeni syndrome in which there is an inherited p53 mutation, and the consequences of immune suppression on p53 mutations and the resulting increase in non-melanoma skin cancer in these patients

  4. Cisplatinum and Taxol Induce Different Patterns of p53 Phosphorylation

    Directory of Open Access Journals (Sweden)

    Giovanna Damia

    2001-01-01

    Full Text Available Posttranslational modifications of p53 induced by two widely used anticancer agents, cisplatinum (DDP and taxol were investigated in two human cancer cell lines. Although both drugs were able to induce phosphorylation at serine 20 (Ser20, only DDP treatment induced p53 phosphorylation at serine 15 (Ser15. Moreover, both drug treatments were able to increase p53 levels and consequently the transcription of waf1 and mdm-2 genes, although DDP treatment resulted in a stronger inducer of both genes. Using two ataxia telangiectasia mutated (ATM cell lines, the role of ATM in druginduced p53 phosphorylations was investigated. No differences in drug-induced p53 phosphorylation could be observed, indicating that ATM is not the kinase involved in these phosphorylation events. In addition, inhibition of DNA-dependent protein kinase activity by wortmannin did not abolish p53 phosphorylation at Ser15 and Ser20, again indicating that DNA-PK is unlikely to be the kinase involved. After both taxol and DDP treatments, an activation of hCHK2 was found and this is likely to be responsible for phosphorylation at Ser20. In contrast, only DDP was able to activate ATR, which is the candidate kinase for phosphorylation of Ser15 by this drug. This data clearly suggests that differential mechanisms are involved in phosphorylation and activation of p53 depending on the drug type.

  5. CLCA2 as a p53-Inducible Senescence Mediator

    Directory of Open Access Journals (Sweden)

    Chizu Tanikawa

    2012-02-01

    Full Text Available p53 is a tumor suppressor gene that is frequently mutated in multiple cancer tissues. Activated p53 protein regulates its downstream genes and subsequently inhibits malignant transformation by inducing cell cycle arrest, apoptosis, DNA repair, and senescence. However, genes involved in the p53-mediated senescence pathway are not yet fully elucidated. Through the screening of two genome-wide expression profile data sets, one for cells in which exogenous p53 was introduced and the other for senescent fibroblasts, we have identified chloride channel accessory 2 (CLCA2 as a p53-inducible senescence-associated gene. CLCA2 was remarkably induced by replicative senescence as well as oxidative stress in a p53-dependent manner. We also found that ectopically expressed CLCA2 induced cellular senescence, and the down-regulation of CLCA2 by small interfering RNA caused inhibition of oxidative stress-induced senescence. Interestingly, the reduced expression of CLCA2 was frequently observed in various kinds of cancers including prostate cancer, whereas its expression was not affected in precancerous prostatic intraepithelial neoplasia. Thus, our findings suggest a crucial role of p53/CLCA2-mediated senescence induction as a barrier for malignant transformation.

  6. HEXIM1, a New Player in the p53 Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lew, Qiao Jing; Chu, Kai Ling; Chia, Yi Ling; Cheong, Nge [Expression Engineering Group, Bioprocessing Technology Institute, A*STAR (Agency for Science, Technology and Research), 20 Biopolis Way, #06-01, Singapore 138668 (Singapore); Chao, Sheng-Hao, E-mail: jimmy_chao@bti.a-star.edu.sg [Expression Engineering Group, Bioprocessing Technology Institute, A*STAR (Agency for Science, Technology and Research), 20 Biopolis Way, #06-01, Singapore 138668 (Singapore); Department of Microbiology, National University of Singapore, Singapore 117597 (Singapore)

    2013-07-04

    Hexamethylene bisacetamide-inducible protein 1 (HEXIM1) is best known as the inhibitor of positive transcription elongation factor b (P-TEFb), which controls transcription elongation of RNA polymerase II and Tat transactivation of human immunodeficiency virus. Besides P-TEFb, several proteins have been identified as HEXIM1 binding proteins. It is noteworthy that more than half of the HEXIM1 binding partners are involved in cancers. P53 and two key regulators of the p53 pathway, nucleophosmin (NPM) and human double minute-2 protein (HDM2), are among the factors identified. This review will focus on the functional importance of the interactions between HEXIM1 and p53/NPM/HDM2. NPM and the cytoplasmic mutant of NPM, NPMc+, were found to regulate P-TEFb activity and RNA polymerase II transcription through the interaction with HEXIM1. Importantly, more than one-third of acute myeloid leukemia (AML) patients carry NPMc+, suggesting the involvement of HEXIM1 in tumorigenesis of AML. HDM2 was found to ubiquitinate HEXIM1. The HDM2-mediated ubiquitination of HEXIM1 did not lead to protein degradation of HEXIM1 but enhanced its inhibitory activity on P-TEFb. Recently, HEXIM1 was identified as a novel positive regulator of p53. HEXIM1 prevented p53 ubiquitination by competing with HDM2 in binding to p53. Taken together, the new evidence suggests a role of HEXIM1 in regulating the p53 pathway and tumorigenesis.

  7. Methylation of PLCD1 and adenovirus-mediated PLCD1 overexpression elicits a gene therapy effect on human breast cancer

    International Nuclear Information System (INIS)

    Mu, Haixi; Wang, Na; Zhao, Lijuan; Li, Shuman; Li, Qianqian; Chen, Ling; Luo, Xinrong; Qiu, Zhu; Li, Lili; Ren, Guosheng; Xu, Yongzhu; Zhou, Xiangyang; Xiang, Tingxiu

    2015-01-01

    Our previous study showed that PLCD1 significantly decreases cell proliferation and affects cell cycle progression in breast cancer cells. In the present study, we aimed to investigate its functional and molecular mechanisms, and whether or not can become a new target for gene therapies. We found reduced PLCD1 protein expression in breast tumor tissues compared with paired surgical margin tissues. PLCD1 promoter CpG methylation was detected in 55 of 96 (57%) primary breast tumors, but not in surgical-margin tissues and normal breast tissues. Ectopic expression of PLCD1 inhibited breast tumor cell proliferation in vivo by inducing apoptosis and suppressed tumor cell migration by regulating cytoskeletal reorganization proteins including RhoA and phospho-cofilin. Furthermore, we found that PLCD1 induced p53 accumulation, increased p27 and p21 protein levels, and cleaved PARP. Finally, we constructed an adenoviral vector expressing PLCD1 (AdH5-PLCD1), which exhibited strong cytotoxicity in breast cancer cells. Our findings provide insights into the development of PLCD1 gene therapies for breast cancer and perhaps, other human cancers. - Highlights: • PLCD1 is downregulated via hypermethylation in breast cancer. • PLCD1 suppressed cell migration by regulating cytoskeletal reorganization proteins. • Adenovirus AdHu5-PLCD1 may be a novel therapeutic option for breast cancer

  8. Methylation of PLCD1 and adenovirus-mediated PLCD1 overexpression elicits a gene therapy effect on human breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Haixi [Molecular Oncology and Epigenetics Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Department of Endocrine and breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Wang, Na; Zhao, Lijuan; Li, Shuman; Li, Qianqian; Chen, Ling; Luo, Xinrong; Qiu, Zhu [Molecular Oncology and Epigenetics Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Li, Lili [Cancer Epigenetics Laboratory, Department of Clinical Oncology, Sir YK Pao Center for Cancer and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong and CUHK Shenzhen Research Institute (Hong Kong); Ren, Guosheng [Molecular Oncology and Epigenetics Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China); Department of Endocrine and breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Xu, Yongzhu [Chongqing Health Service Center, Chongqing 400020 (China); Zhou, Xiangyang [The Wistar Institute, Philadelphia, PA (United States); Xiang, Tingxiu, E-mail: xiangtx1@gmail.com [Molecular Oncology and Epigenetics Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing (China)

    2015-03-15

    Our previous study showed that PLCD1 significantly decreases cell proliferation and affects cell cycle progression in breast cancer cells. In the present study, we aimed to investigate its functional and molecular mechanisms, and whether or not can become a new target for gene therapies. We found reduced PLCD1 protein expression in breast tumor tissues compared with paired surgical margin tissues. PLCD1 promoter CpG methylation was detected in 55 of 96 (57%) primary breast tumors, but not in surgical-margin tissues and normal breast tissues. Ectopic expression of PLCD1 inhibited breast tumor cell proliferation in vivo by inducing apoptosis and suppressed tumor cell migration by regulating cytoskeletal reorganization proteins including RhoA and phospho-cofilin. Furthermore, we found that PLCD1 induced p53 accumulation, increased p27 and p21 protein levels, and cleaved PARP. Finally, we constructed an adenoviral vector expressing PLCD1 (AdH5-PLCD1), which exhibited strong cytotoxicity in breast cancer cells. Our findings provide insights into the development of PLCD1 gene therapies for breast cancer and perhaps, other human cancers. - Highlights: • PLCD1 is downregulated via hypermethylation in breast cancer. • PLCD1 suppressed cell migration by regulating cytoskeletal reorganization proteins. • Adenovirus AdHu5-PLCD1 may be a novel therapeutic option for breast cancer.

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

    International Nuclear Information System (INIS)

    Kang, Han Na; Oh, Sang Cheul; Kim, Jun Suk; Yoo, Young A.

    2012-01-01

    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.

  10. POSTRANSLATIONAL MODIFICATIONS OF P53: UPSTREAM SIGNALING PATHWAYS.

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON,C.W.APPELLA,E.

    2003-10-23

    The p53 tumor suppressor is a tetrameric transcription factor that is posttranslational modified at >20 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review recent progress in characterizing the upstream signaling pathways whose activation in response to various genotoxic and non-genotoxic stresses result in p53 posttranslational modifications.

  11. P53 expression in prostatic cancer: an immunohistochemical study

    International Nuclear Information System (INIS)

    Al-Nuaimy, W.M.; Al-Allaf, L.I.; Alnaimi, H.A.

    2011-01-01

    Prostate cancer is the most common malignancy in men and second leading cause of cancer death in the Western world. P53 alterations are the most frequent genetic changes in human cancers. Mutation of the p53 gene has been implicated in the development of >50% of all human cancer. The current study aims at evaluating the immuno-histochemical expression of p53 protein in patients with cancer of prostate, as prognostic parameter in correlation with other parameters including PSA receptors, and to correlate the results with those of other studies. (authors).

  12. Robustness of the p53 network and biological hackers.

    Science.gov (United States)

    Dartnell, Lewis; Simeonidis, Evangelos; Hubank, Michael; Tsoka, Sophia; Bogle, I David L; Papageorgiou, Lazaros G

    2005-06-06

    The p53 protein interaction network is crucial in regulating the metazoan cell cycle and apoptosis. Here, the robustness of the p53 network is studied by analyzing its degeneration under two modes of attack. Linear Programming is used to calculate average path lengths among proteins and the network diameter as measures of functionality. The p53 network is found to be robust to random loss of nodes, but vulnerable to a targeted attack against its hubs, as a result of its architecture. The significance of the results is considered with respect to mutational knockouts of proteins and the directed attacks mounted by tumour inducing viruses.

  13. Clinical significance of altered nm23-H1, EGFR, RB and p53 expression in bilharzial bladder cancer

    International Nuclear Information System (INIS)

    Khaled, Hussein M; Bahnassy, Abeer A; Raafat, Amira A; Zekri, Abdel-Rahman N; Madboul, Maha S; Mokhtar, Nadia M

    2009-01-01

    Clinical characterization of bladder carcinomas is still inadequate using the standard clinico-pathological prognostic markers. We assessed the correlation between nm23-H1, Rb, EGFR and p53 in relation to the clinical outcome of patients with muscle invasive bilharzial bladder cancer (MI-BBC). nm23-H1, Rb, EGFR and p53 expression was assessed in 59 MI-BBC patients using immunohistochemistry and reverse transcription (RT-PCR) and was correlated to the standard clinico-pathological prognostic factors, patient's outcome and the overall survival (OS) rate. Overexpression of EGFR and p53 proteins was detected in 66.1% and 35.6%; respectively. Loss of nm23-H1and Rb proteins was detected in 42.4% and 57.6%; respectively. Increased EGFR and loss of nm23-H1 RNA were detected in 61.5% and 36.5%; respectively. There was a statistically significant correlation between p53 and EGFR overexpression (p < 0.0001), nm23 loss (protein and RNA), lymph node status (p < 0.0001); between the incidence of local recurrence and EGFR RNA overexpression (p= 0.003) as well as between the incidence of metastasis and altered Rb expression (p = 0.026), p53 overexpression (p < 0.0001) and mutation (p = 0.04). Advanced disease stage correlated significantly with increased EGFR (protein and RNA) (p = 0.003 & 0.01), reduced nm23-H1 RNA (p = 0.02), altered Rb (p = 0.023), and p53 overexpression (p = 0.004). OS rates correlated significantly, in univariate analysis, with p53 overexpression (p = 0.011), increased EGFR (protein and RNA, p = 0.034&0.031), nm23-H1 RNA loss (p = 0.021) and aberrations of ≥ 2 genes. However, multivariate analysis showed that only high EGFR overexpression, metastatic recurrence, high tumor grade and the combination of ≥ 2 affected markers were independent prognostic factors. nm23-H1, EGFR and p53 could be used as prognostic biomarkers in MI-BBC patients. In addition to the standard pathological prognostic factors, a combination of these markers (≥ 2) has

  14. Apoptosis and cell proliferation in the development of gastric carcinomas: associations with c-myc and p53 protein expression.

    Science.gov (United States)

    Ishii, Hideaki H; Gobé, Glenda C; Pan, Wenshen; Yoneyama, Juichi; Ebihara, Yoshiro

    2002-09-01

    Patients with gastric carcinomas have a poor prognosis and low survival rates. The aim of the present paper was to characterize cellular and molecular properties to provide insight into aspects of tumor progression in early compared with advanced gastric cancers. One hundred and nine graded gastric carcinomas (early or advanced stage, undifferentiated or differentiated type) with paired non-cancer tissue were studied to define the correlation between apoptosis (morphology, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling), cell proliferation (Ki-67 expression, morphology) and expression and localization of two proteins frequently having altered expression in cancers, namely p53 and c-myc. Overall, apoptosis was lower in early stage, differentiated and undifferentiated gastric carcinomas compared with advanced-stage cancers. Cell proliferation was comparatively high in all stages. There was a high level of p53 positivity in all stages. Only the early- and advanced-stage undifferentiated cancers that were p53 positive had a significantly higher level of apoptosis (P cancers that had either c-myc or p53-positivity. The results indicate that low apoptosis and high cell proliferation combine to drive gastric cancer development. The molecular controls for high cell proliferation of the early stage undifferentiated gastric cancers involve overexpression of both p53 and c-myc. Overexpression of p53 may also control cancer development in that its expression is associated with higher levels of apoptosis in early and late-stage undifferentiated, cancers. Copyright 2002 Blackwell Publishing Asia Pty Ltd

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

    International Nuclear Information System (INIS)

    Abd El-Maqsoud, N.M.R.; Tawfiek, E.R.

    2010-01-01

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

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

    Science.gov (United States)

    XU, HE N.; FENG, MIN; MOON, LILY; DOLLOFF, NATHAN; EL-DEIRY, WAFIK; LI, LIN Z.

    2015-01-01

    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

  17. Limited role of murine ATM in oncogene-induced senescence and p53-dependent tumor suppression.

    Directory of Open Access Journals (Sweden)

    Alejo Efeyan

    Full Text Available Recent studies in human fibroblasts have provided a new general paradigm of tumor suppression according to which oncogenic signaling produces DNA damage and this, in turn, results in ATM/p53-dependent cellular senescence. Here, we have tested this model in a variety of murine experimental systems. Overexpression of oncogenic Ras in murine fibroblasts efficiently induced senescence but this occurred in the absence of detectable DNA damage signaling, thus suggesting a fundamental difference between human and murine cells. Moreover, lung adenomas initiated by endogenous levels of oncogenic K-Ras presented abundant senescent cells, but undetectable DNA damage signaling. Accordingly, K-Ras-driven adenomas were also senescent in Atm-null mice, and the tumorigenic progression of these lesions was only modestly accelerated by Atm-deficiency. Finally, we have examined chemically-induced fibrosarcomas, which possess a persistently activated DNA damage response and are highly sensitive to the activity of p53. We found that the absence of Atm favored genomic instability in the resulting tumors, but did not affect the persistent DNA damage response and did not impair p53-dependent tumor suppression. All together, we conclude that oncogene-induced senescence in mice may occur in the absence of a detectable DNA damage response. Regarding murine Atm, our data suggest that it plays a minor role in oncogene-induced senescence or in p53-dependent tumor suppression, being its tumor suppressive activity probably limited to the maintenance of genomic stability.

  18. Structural effects and competition mechanisms targeting the interactions between p53 and MDM2 for cancer therapy

    Science.gov (United States)

    Liu, Shu-Xia; Geng, Yi-Zhao; Yan, Shi-Wei

    2017-06-01

    Approximately half of all human cancers show normal TP53 gene expression but aberrant overexpression of MDM2 and/or MDMX. This fact suggests a promising cancer therapeutic strategy in targeting the interactions between p53 and MDM2/MDMX. To help realize the goal of developing effective inhibitors to disrupt the p53-MDM2/MDMX interaction, we systematically investigated the structural and interaction characteristics of p53 with inhibitors of its interactions with MDM2 and MDMX from an atomistic perspective using stochastic molecular dynamics simulations. We found that some specific α helices in the structures of MDM2 and MDMX play key roles in their binding to inhibitors, and that the hydrogen bond formed by the Trp23 residue of p53 with its counterpart in MDM2 or MDMX determines the dynamic competition processes of the disruption of the MDM2-p53 interaction and replacement of p53 from the MDM2-p53 complex in vivo. The results reported in this paper are expected to provide basic information for designing functional inhibitors and realizing new strategies of cancer gene therapy.

  19. Expression of p53, MDM2 in a mice hydradecarcinoma model induced by γ-ray irradiation

    International Nuclear Information System (INIS)

    Huang Yuecheng; Cai Jianming; Han Ling; Gao Fu; Sun Ding; Dong Zhitao; Zhe Wanli

    2004-01-01

    Objective: To investigate the role of the p53, MDM2 in carcinogenesis of mice hydradecarcinoma induced by γ-rays. Methods: A radiation-induced mice hydradecarcinoma model was established by γ-ray irradiation. Expression of MDM2 protein in hydradecarcinoma tissue, paracancerous tissue and normal control tissue was detected with Western blot. Immunoprecipitation (IP) was conducted to examine the phosphorylation level of MDM2 protein. PCR-SSCP was performed to detect p53 gene mutation. Results: Compared with the normal control tissue, the MDM2 protein expression and its phosphorylation level were significantly higher in hydradecarcinoma tissue. SSCP showed there were p53 gene mutations in hydradecarcinoma samples. Conclusion: p53/MDM2 pathway may be involved in the development and progression of hydradecarcinoma induced by γ-ray irradiation. The over-expression of MDM2 and hyperphosphorylation may be responsible for malignant transformation induced by irradiation by a possible mechanism of p53 inactivation. The gene mutation of p53 further supported the hypothesis that p53/MDM2 pathway played a central role in carcinogenesis of γray induced hydradecarcinoma. (authors)

  20. A dynamic P53-MDM2 model with time delay

    Energy Technology Data Exchange (ETDEWEB)

    Mihalas, Gh.I. [Department of Biophysics and Medical Informatics, University of Medicine and Pharmacy, Piata Eftimie Murgu, nr. 3, 300041 Timisoara (Romania)]. E-mail: mihalas@medinfo.umft.ro; Neamtu, M. [Department of Forecasting, Economic Analysis, Mathematics and Statistics, West University of Timisoara, Str. Pestalozzi, nr. 14A, 300115 Timisoara (Romania)]. E-mail: mihaela.neamtu@fse.uvt.ro; Opris, D. [Department of Applied Mathematics, West University of Timisoara, Bd. V. Parvan, nr. 4, 300223 Timisoara (Romania)]. E-mail: opris@math.uvt.ro; Horhat, R.F. [Department of Biophysics and Medical Informatics, University of Medicine and Pharmacy, Piata Eftimie Murgu, nr. 3, 300041 Timisoara (Romania)]. E-mail: rhorhat@yahoo.com

    2006-11-15

    Specific activator and repressor transcription factors which bind to specific regulator DNA sequences, play an important role in gene activity control. Interactions between genes coding such transcription factors should explain the different stable or sometimes oscillatory gene activities characteristic for different tissues. Starting with the model P53-MDM2 described into [Mihalas GI, Simon Z, Balea G, Popa E. Possible oscillatory behaviour in P53-MDM2 interaction computer simulation. J Biol Syst 2000;8(1):21-9] and the process described into [Kohn KW, Pommier Y. Molecular interaction map of P53 and MDM2 logic elements, which control the off-on switch of P53 in response to DNA damage. Biochem Biophys Res Commun 2005;331:816-27] we enveloped a new model of this interaction. Choosing the delay as a bifurcation parameter we study the direction and stability of the bifurcating periodic solutions. Some numerical examples are finally given for justifying the theoretical results.

  1. A dynamic P53-MDM2 model with time delay

    International Nuclear Information System (INIS)

    Mihalas, Gh.I.; Neamtu, M.; Opris, D.; Horhat, R.F.

    2006-01-01

    Specific activator and repressor transcription factors which bind to specific regulator DNA sequences, play an important role in gene activity control. Interactions between genes coding such transcription factors should explain the different stable or sometimes oscillatory gene activities characteristic for different tissues. Starting with the model P53-MDM2 described into [Mihalas GI, Simon Z, Balea G, Popa E. Possible oscillatory behaviour in P53-MDM2 interaction computer simulation. J Biol Syst 2000;8(1):21-9] and the process described into [Kohn KW, Pommier Y. Molecular interaction map of P53 and MDM2 logic elements, which control the off-on switch of P53 in response to DNA damage. Biochem Biophys Res Commun 2005;331:816-27] we enveloped a new model of this interaction. Choosing the delay as a bifurcation parameter we study the direction and stability of the bifurcating periodic solutions. Some numerical examples are finally given for justifying the theoretical results

  2. Role of P53 in Mammary Epithelial Cell Senescence

    National Research Council Canada - National Science Library

    Dimri, Goberdhan P

    2006-01-01

    .... We also chose several other targets of p53 that are induced by DNA damage. The RT PCR analysis aws carried out using mRNA prepared from young growing early passage and senescent late passage HMECs...

  3. Polymorphism at codon 36 of the p53 gene.

    Science.gov (United States)

    Felix, C A; Brown, D L; Mitsudomi, T; Ikagaki, N; Wong, A; Wasserman, R; Womer, R B; Biegel, J A

    1994-01-01

    A polymorphism at codon 36 in exon 4 of the p53 gene was identified by single strand conformation polymorphism (SSCP) analysis and direct sequencing of genomic DNA PCR products. The polymorphic allele, present in the heterozygous state in genomic DNAs of four of 100 individuals (4%), changes the codon 36 CCG to CCA, eliminates a FinI restriction site and creates a BccI site. Including this polymorphism there are four known polymorphisms in the p53 coding sequence.

  4. Post-translational regulation enables robust p53 regulation.

    Science.gov (United States)

    Shin, Yong-Jun; Chen, Kai-Yuan; Sayed, Ali H; Hencey, Brandon; Shen, Xiling

    2013-08-30

    The tumor suppressor protein p53 plays important roles in DNA damage repair, cell cycle arrest and apoptosis. Due to its critical functions, the level of p53 is tightly regulated by a negative feedback mechanism to increase its tolerance towards fluctuations and disturbances. Interestingly, the p53 level is controlled by post-translational regulation rather than transcriptional regulation in this feedback mechanism. We analyzed the dynamics of this feedback to understand whether post-translational regulation provides any advantages over transcriptional regulation in regard to disturbance rejection. When a disturbance happens, even though negative feedback reduces the steady-state error, it can cause a system to become less stable and transiently overshoots, which may erroneously trigger downstream reactions. Therefore, the system needs to balance the trade-off between steady-state and transient errors. Feedback control and adaptive estimation theories revealed that post-translational regulation achieves a better trade-off than transcriptional regulation, contributing to a more steady level of p53 under the influence of noise and disturbances. Furthermore, post-translational regulation enables cells to respond more promptly to stress conditions with consistent amplitude. However, for better disturbance rejection, the p53- Mdm2 negative feedback has to pay a price of higher stochastic noise. Our analyses suggest that the p53-Mdm2 feedback favors regulatory mechanisms that provide the optimal trade-offs for dynamic control.

  5. Thymocyte apoptosis induced by p53-dependent and independent pathways

    International Nuclear Information System (INIS)

    Clarke, A.R.; Purdie, C.A.; Harrison, D.J.; Morris, R.G.; Bird, C.C.; Hooper, M.L.; Wyllie, A.H.

    1993-01-01

    The authors studied the dependence of apoptosis on p53 expression in cells from the thymus cortex. Short-term thymocyte cultures were prepared from mice constitutively heterozygous or homozygous for a deletion in the p53 gene introduced into the germ line after gene targeting. Wild-type thymocytes readily undergo apoptosis after treatment with ionizing radiation, the glucocorticoid methylprednisolone, or etoposide (an inhibitor of topoisomerase II), or after Ca 2+ -dependent activation by phorbol ester and a calcium ionophore. In contrast, homozygous null p53 thymocytes are resistant to induction of apoptosis by radiation or etoposide, but retain normal sensitivity to glucocorticoid and calcium. The time-dependent apoptosis that occurs in untreated cultures is unaffected by p53 status. Cells heterozygous for p53 deletion are partially resistant to radiation and etoposide. Results show that p53 exerts a significant and dose-dependent effect in the initiation of apoptosis, but only when it is induced by agents that cause DNA-strand breakage. (Author)

  6. 40 Years of Research Put p53 in Translation

    Science.gov (United States)

    Marcel, Virginie; Nguyen Van Long, Flora; Diaz, Jean-Jacques

    2018-01-01

    Since its discovery in 1979, p53 has shown multiple facets. Initially the tumor suppressor p53 protein was considered as a stress sensor able to maintain the genome integrity by regulating transcription of genes involved in cell cycle arrest, apoptosis and DNA repair. However, it rapidly came into light that p53 regulates gene expression to control a wider range of biological processes allowing rapid cell adaptation to environmental context. Among them, those related to cancer have been extensively documented. In addition to its role as transcription factor, scattered studies reported that p53 regulates miRNA processing, modulates protein activity by direct interaction or exhibits RNA-binding activity, thus suggesting a role of p53 in regulating several layers of gene expression not restricted to transcription. After 40 years of research, it appears more and more clearly that p53 is strongly implicated in translational regulation as well as in the control of the production and activity of the translational machinery. Translation control of specific mRNAs could provide yet unsuspected capabilities to this well-known guardian of the genome.

  7. Overexpression of SERBP1 (Plasminogen activator inhibitor 1 RNA binding protein) in human breast cancer is correlated with favourable prognosis

    International Nuclear Information System (INIS)

    Serce, Nuran Bektas; Knuechel, Ruth; Beckmann, Matthias W; Fasching, Peter A; Dahl, Edgar; Boesl, Andreas; Klaman, Irina; Serényi, Sonja von; Noetzel, Erik; Press, Michael F; Dimmler, Arno; Hartmann, Arndt; Sehouli, Jalid

    2012-01-01

    Plasminogen activator inhibitor 1 (PAI-1) overexpression is an important prognostic and predictive biomarker in human breast cancer. SERBP1, a protein that is supposed to regulate the stability of PAI-1 mRNA, may play a role in gynaecological cancers as well, since upregulation of SERBP1 was described in ovarian cancer recently. This is the first study to present a systematic characterisation of SERBP1 expression in human breast cancer and normal breast tissue at both the mRNA and the protein level. Using semiquantitative realtime PCR we analysed SERBP1 expression in different normal human tissues (n = 25), and in matched pairs of normal (n = 7) and cancerous breast tissues (n = 7). SERBP1 protein expression was analysed in two independent cohorts on tissue microarrays (TMAs), an initial evaluation set, consisting of 193 breast carcinomas and 48 normal breast tissues, and a second large validation set, consisting of 605 breast carcinomas. In addition, a collection of benign (n = 2) and malignant (n = 6) mammary cell lines as well as breast carcinoma lysates (n = 16) were investigated for SERBP1 expression by Western blot analysis. Furthermore, applying non-radioisotopic in situ hybridisation a subset of normal (n = 10) and cancerous (n = 10) breast tissue specimens from the initial TMA were analysed for SERBP1 mRNA expression. SERBP1 is not differentially expressed in breast carcinoma compared to normal breast tissue, both at the RNA and protein level. However, recurrence-free survival analysis showed a significant correlation (P = 0.008) between abundant SERBP1 expression in breast carcinoma and favourable prognosis. Interestingly, overall survival analysis also displayed a tendency (P = 0.09) towards favourable prognosis when SERBP1 was overexpressed in breast cancer. The RNA-binding protein SERBP1 is abundantly expressed in human breast cancer and may represent a novel breast tumour marker with prognostic significance. Its potential involvement in the

  8. p53-Dependent radiation-induced apoptosis in vivo: relationship to Bcl-2 and Bax expression

    International Nuclear Information System (INIS)

    Hasegawa, Masatoshi; Suzuki, Yoshiyuki; Furuta, Masaya; Yamakawa, Michitaka; Maebayashi, Katsuya; Hayakawa, Kayoko; Saito, Yoshihiro; Mitsuhashi, Norio; Niibe, Hideo

    1997-01-01

    , but negative for p21 and Bax. They did not show significant differences between before and after irradiation. These three tumors often showed very weak staining for Bax, and it was much weaker than in the positive control slides. PCR-SSCP analysis showed a mutation in exon 7 of the p53 gene in the glioblastoma and the small cell lung cancer, but, no mutations were demonstrated in exons of the p53 gene in the ependymoblastoma. Conclusion: The radiation-induced apoptosis in the ependymoblastoma was highly correlated with p53 protein expression, but, the changes in Bcl-2 and Bax expression did not always correspond to the frequency of apoptosis. In the other two tumors, radiation induced apoptosis in only a few cells. These tumors showed overexpression of p53 and Bcl-2, and a mutation of p53 gene was also suggested by PCR-SSCP analysis

  9. Differential effects of garcinol and curcumin on histone and p53 modifications in tumour cells

    Directory of Open Access Journals (Sweden)

    Collins Hilary M

    2013-01-01

    Full Text Available Abstract Background Post-translational modifications (PTMs of histones and other proteins are perturbed in tumours. For example, reduced levels of acetylated H4K16 and trimethylated H4K20 are associated with high tumour grade and poor survival in breast cancer. Drug-like molecules that can reprogram selected histone PTMs in tumour cells are therefore of interest as potential cancer chemopreventive agents. In this study we assessed the effects of the phytocompounds garcinol and curcumin on histone and p53 modification in cancer cells, focussing on the breast tumour cell line MCF7. Methods Cell viability/proliferation assays, cell cycle analysis by flow cytometry, immunodetection of specific histone and p53 acetylation marks, western blotting, siRNA and RT-qPCR. Results Although treatment with curcumin, garcinol or the garcinol derivative LTK-14 hampered MCF7 cell proliferation, differential effects of these compounds on histone modifications were observed. Garcinol treatment resulted in a strong reduction in H3K18 acetylation, which is required for S phase progression. Similar effects of garcinol on H3K18 acetylation were observed in the osteosarcoma cells lines U2OS and SaOS2. In contrast, global levels of acetylated H4K16 and trimethylated H4K20 in MCF7 cells were elevated after garcinol treatment. This was accompanied by upregulation of DNA damage signalling markers such as γH2A.X, H3K56Ac, p53 and TIP60. In contrast, exposure of MCF7 cells to curcumin resulted in increased global levels of acetylated H3K18 and H4K16, and was less effective in inducing DNA damage markers. In addition to its effects on histone modifications, garcinol was found to block CBP/p300-mediated acetylation of the C-terminal activation domain of p53, but resulted in enhanced acetylation of p53K120, and accumulation of p53 in the cytoplasmic compartment. Finally, we show that the elevation of H4K20Me3 levels by garcinol correlated with increased expression of SUV420H2

  10. Differential effects of garcinol and curcumin on histone and p53 modifications in tumour cells

    International Nuclear Information System (INIS)

    Collins, Hilary M; Kundu, Tapas K; Heery, David M; Abdelghany, Magdy K; Messmer, Marie; Yue, Baigong; Deeves, Sian E; Kindle, Karin B; Mantelingu, Kempegowda; Aslam, Akhmed; Winkler, G Sebastiaan

    2013-01-01

    Post-translational modifications (PTMs) of histones and other proteins are perturbed in tumours. For example, reduced levels of acetylated H4K16 and trimethylated H4K20 are associated with high tumour grade and poor survival in breast cancer. Drug-like molecules that can reprogram selected histone PTMs in tumour cells are therefore of interest as potential cancer chemopreventive agents. In this study we assessed the effects of the phytocompounds garcinol and curcumin on histone and p53 modification in cancer cells, focussing on the breast tumour cell line MCF7. Cell viability/proliferation assays, cell cycle analysis by flow cytometry, immunodetection of specific histone and p53 acetylation marks, western blotting, siRNA and RT-qPCR. Although treatment with curcumin, garcinol or the garcinol derivative LTK-14 hampered MCF7 cell proliferation, differential effects of these compounds on histone modifications were observed. Garcinol treatment resulted in a strong reduction in H3K18 acetylation, which is required for S phase progression. Similar effects of garcinol on H3K18 acetylation were observed in the osteosarcoma cells lines U2OS and SaOS2. In contrast, global levels of acetylated H4K16 and trimethylated H4K20 in MCF7 cells were elevated after garcinol treatment. This was accompanied by upregulation of DNA damage signalling markers such as γH2A.X, H3K56Ac, p53 and TIP60. In contrast, exposure of MCF7 cells to curcumin resulted in increased global levels of acetylated H3K18 and H4K16, and was less effective in inducing DNA damage markers. In addition to its effects on histone modifications, garcinol was found to block CBP/p300-mediated acetylation of the C-terminal activation domain of p53, but resulted in enhanced acetylation of p53K120, and accumulation of p53 in the cytoplasmic compartment. Finally, we show that the elevation of H4K20Me3 levels by garcinol correlated with increased expression of SUV420H2, and was prevented by siRNA targeting of SUV420H2. In

  11. p53-competent cells and p53-deficient cells display different susceptibility to oxygen functionalized graphene cytotoxicity and genotoxicity.

    Science.gov (United States)

    Petibone, Dayton M; Mustafa, Thikra; Bourdo, Shawn E; Lafont, Andersen; Ding, Wei; Karmakar, Alokita; Nima, Zeid A; Watanabe, Fumiya; Casciano, Daniel; Morris, Suzanne M; Dobrovolsky, Vasily N; Biris, Alexandru S

    2017-11-01

    Due to the distinctive physical, electrical, and chemical properties of graphene nanomaterials, numerous efforts pursuing graphene-based biomedical and industrial applications are underway. Oxidation of pristine graphene surfaces mitigates its otherwise hydrophobic characteristic thereby improving its biocompatibility and functionality. Yet, the potential widespread use of oxidized graphene derivatives raises concern about adverse impacts on human health. The p53 tumor suppressor protein maintains cellular and genetic stability after toxic exposures. Here, we show that p53 functional status correlates with oxygen functionalized graphene (f-G) cytotoxicity and genotoxicity in vitro. The f-G exposed p53-competent cells, but not p53-deficient cells, initiated G 0 /G 1 phase cell cycle arrest, suppressed reactive oxygen species, and entered apoptosis. There was p53-dependent f-G genotoxicity evident as increased structural chromosome damage, but not increased gene mutation or chromatin loss. In conclusion, the cytotoxic and genotoxic potential for f-G in exposed cells was dependent on the p53 functional status. These findings have broad implications for the safe and effective implementation of oxidized graphene derivatives into biomedical and industrial applications. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Published 2017. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

  12. R248Q mutation--Beyond p53-DNA binding.

    Science.gov (United States)

    Ng, Jeremy W K; Lama, Dilraj; Lukman, Suryani; Lane, David P; Verma, Chandra S; Sim, Adelene Y L

    2015-12-01

    R248 in the DNA binding domain (DBD) of p53 interacts directly with the minor groove of DNA. Earlier nuclear magnetic resonance (NMR) studies indicated that the R248Q mutation resulted in conformation changes in parts of DBD far from the mutation site. However, how information propagates from the mutation site to the rest of the DBD is still not well understood. We performed a series of all-atom molecular dynamics (MD) simulations to dissect sterics and charge effects of R248 on p53-DBD conformation: (i) wild-type p53 DBD; (ii) p53 DBD with an electrically neutral arginine side-chain; (iii) p53 DBD with R248A; (iv) p53 DBD with R248W; and (v) p53 DBD with R248Q. Our results agree well with experimental observations of global conformational changes induced by the R248Q mutation. Our simulations suggest that both charge- and sterics are important in the dynamics of the loop (L3) where the mutation resides. We show that helix 2 (H2) dynamics is altered as a result of a change in the hydrogen bonding partner of D281. In turn, neighboring L1 dynamics is altered: in mutants, L1 predominantly adopts the recessed conformation and is unable to interact with the major groove of DNA. We focused our attention the R248Q mutant that is commonly found in a wide range of cancer and observed changes at the zinc-binding pocket that might account for the dominant negative effects of R248Q. Furthermore, in our simulations, the S6/S7 turn was more frequently solvent exposed in R248Q, suggesting that there is a greater tendency of R248Q to partially unfold and possibly lead to an increased aggregation propensity. Finally, based on the observations made in our simulations, we propose strategies for the rescue of R248Q mutants. © 2015 Wiley Periodicals, Inc.

  13. Influence of P53 on the radiotherapy response of hepatocellular carcinoma

    Science.gov (United States)

    Gomes, Ana R.; Abrantes, Ana M.; Brito, Ana F.; Laranjo, Mafalda; Casalta-Lopes, João E.; Gonçalves, Ana C.; Sarmento-Ribeiro, Ana B.; Tralhão, José G.

    2015-01-01

    Background/Aims Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and it has a poor prognosis and few therapeutic options. Radiotherapy is one of the most effective forms of cancer treatment, and P53 protein is one of the key molecules determining how a cell responds to radiotherapy. The aim of this study was to determine the therapeutic efficacy of iodine-131 in three human HCC cell lines. Methods Western blotting was used to measure P53 expression. The effects of radiotherapy with iodine-131 were assessed by using the clonogenic assay to evaluate cell survival. Flow cytometry was carried out to examine the effects of iodine-131 on cell death, oxidative stress, reduced intracellular glutathione expression, the mitochondrial membrane potential, and the cell cycle. Results The P53 protein was not expressed in Hep3B2.1-7 cells, was expressed at normal levels in HepG2 cells, and was overexpressed in HuH7 cells. P53 expression in the HuH7 and HepG2 cell lines increased after internal and external irradiation with iodine-131. Irradiation induced a decrease in cell survival and led to a decrease in cell viability in all of the cell lines studied, accompanied by cell death via late apoptosis/necrosis and necrosis. Irradiation with 131-iodine induced mostly cell-cycle arrest in the G0/G1 phase. Conclusions These results suggest that P53 plays a key role in the radiotherapy response of HCC. PMID:26527121

  14. ATM and p53 combined analysis predicts survival in glioblastoma multiforme patients: A clinicopathologic study.

    Science.gov (United States)

    Romano, Francesco Jacopo; Guadagno, Elia; Solari, Domenico; Borrelli, Giorgio; Pignatiello, Sara; Cappabianca, Paolo; Del Basso De Caro, Marialaura

    2018-06-01

    Glioblastoma is one of the most malignant cancers, with a distinguishing dismal prognosis: surgery followed by chemo- and radiotherapy represents the current standard of care, and chemo- and radioresistance underlie disease recurrence and short overall survival of patients suffering from this malignancy. ATM is a kinase activated by autophosphorylation upon DNA doublestrand breaks arising from errors during replication, byproducts of metabolism, chemotherapy or ionizing radiations; TP53 is one of the most popular tumor suppressor, with a preeminent role in DNA damage response and repair. To study the effects of the immunohistochemical expression of p-ATM and p53 in glioblastoma patients, 21 cases were retrospectively examined. In normal brain tissue, p-ATM was expressed only in neurons; conversely, in tumors cells, the protein showed a variable cytoplasmic expression (score: +,++,+++), with being completely undetectable in three cases. Statistical analysis revealed that high p-ATM score (++/+++) strongly correlated to shorter survival (P = 0.022). No difference in overall survival was registered between p53 normally expressed (NE) and overexpressed (OE) glioblastoma patients (P = 0.669). Survival analysis performed on the results from combined assessment of the two proteins showed that patients with NE p53 /low pATM score had longer overall survival than the NE p53/ high pATM score counterpart. Cox-regression analysis confirmed this finding (HR = 0.025; CI 95% = 0.002-0.284; P = 0.003). Our study outlined the immunohistochemical expression of p-ATM/p53 in glioblastomas and provided data on their possible prognostic/predictive of response role. A "non-oncogene addiction" to ATM for NEp53 glioblastoma could be postulated, strengthening the rationale for development of ATM inhibiting drugs. © 2018 Wiley Periodicals, Inc.

  15. System-based strategies for p53 recovery.

    Science.gov (United States)

    Azam, Muhammad Rizwan; Fazal, Sahar; Ullah, Mukhtar; Bhatti, Aamer I

    2018-06-01

    The authors have proposed a systems theory-based novel drug design approach for the p53 pathway. The pathway is taken as a dynamic system represented by ordinary differential equations-based mathematical model. Using control engineering practices, the system analysis and subsequent controller design is performed for the re-activation of wild-type p53. p53 revival is discussed for both modes of operation, i.e. the sustained and oscillatory. To define the problem in control system paradigm, modification in the existing mathematical model is performed to incorporate the effect of Nutlin. Attractor point analysis is carried out to select the suitable domain of attraction. A two-loop negative feedback control strategy is devised to drag the system trajectories to the attractor point and to regulate cellular concentration of Nutlin, respectively. An integrated framework is constituted to incorporate the pharmacokinetic effects of Nutlin in the cancerous cells. Bifurcation analysis is also performed on the p53 model to see the conditions for p53 oscillation.

  16. 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.

  17. Generation of a selectively cytotoxic fusion protein against p53 mutated cancers

    International Nuclear Information System (INIS)

    Kousparou, Christina A; Yiacoumi, Efthymia; Deonarain, Mahendra P; Epenetos, Agamemnon A

    2012-01-01

    A significant number of cancers are caused by defects in p21 causing functional defects in p21 or p53 tumour-suppressor proteins. This has led to many therapeutic approaches including restoration by gene therapy with wild-type p53 or p21 using viral or liposomal vectors, which have toxicity or side-effect limitations. We set out to develop a safer, novel fusion protein which has the ability to reconstitute cancer cell lines with active p21 by protein transduction. The fusion protein was produced from the cell-translocating peptide Antennapedia (Antp) and wild-type, full-length p21 (Antp-p21). This was expressed and refolded from E. coli and tested on a variety of cell lines and tumours (in a BALB/c nude xenograft model) with differing p21 or p53 status. Antp-p21 penetrated and killed cancer cells that do not express wild type p53 or p21. This included cells that were matched to cogenic parental cell lines. Antp-p21 killed cancer cells selectively that were malignant as a result of mutations or nuclear exclusion of the p53 and p21 genes and over-expression of MDM2. Non-specific toxicity was excluded by showing that Antp-p21 penetrated but did not kill p53- or p21- wild-type cells. Antp-p21 was not immunogenic in normal New Zealand White rabbits. Recombinant Antp peptide alone was not cytotoxic, showing that killing was due to the transduction of the p21 component of Antp-p21. Antp-p21 was shown to penetrate cancer cells engrafted in vivo and resulted in tumour eradication when administered with conventionally-used chemotherapeutic agents, which alone were unable to produce such an effect. Antp-p21 may represent a new and promising targeted therapy for patients with p53-associated cancers supporting the concept that rational design of therapies directed against specific cancer mutations will play a part in the future of medical oncology

  18. Generation of a selectively cytotoxic fusion protein against p53 mutated cancers

    Directory of Open Access Journals (Sweden)

    Kousparou Christina A

    2012-08-01

    Full Text Available Abstract Background A significant number of cancers are caused by defects in p21 causing functional defects in p21 or p53 tumour-suppressor proteins. This has led to many therapeutic approaches including restoration by gene therapy with wild-type p53 or p21 using viral or liposomal vectors, which have toxicity or side-effect limitations. We set out to develop a safer, novel fusion protein which has the ability to reconstitute cancer cell lines with active p21 by protein transduction. Methods The fusion protein was produced from the cell-translocating peptide Antennapedia (Antp and wild-type, full-length p21 (Antp-p21. This was expressed and refolded from E. coli and tested on a variety of cell lines and tumours (in a BALB/c nude xenograft model with differing p21 or p53 status. Results Antp-p21 penetrated and killed cancer cells that do not express wild type p53 or p21. This included cells that were matched to cogenic parental cell lines. Antp-p21 killed cancer cells selectively that were malignant as a result of mutations or nuclear exclusion of the p53 and p21 genes and over-expression of MDM2. Non-specific toxicity was excluded by showing that Antp-p21 penetrated but did not kill p53- or p21- wild-type cells. Antp-p21 was not immunogenic in normal New Zealand White rabbits. Recombinant Antp peptide alone was not cytotoxic, showing that killing was due to the transduction of the p21 component of Antp-p21. Antp-p21 was shown to penetrate cancer cells engrafted in vivo and resulted in tumour eradication when administered with conventionally-used chemotherapeutic agents, which alone were unable to produce such an effect. Conclusions Antp-p21 may represent a new and promising targeted therapy for patients with p53-associated cancers supporting the concept that rational design of therapies directed against specific cancer mutations will play a part in the future of medical oncology.

  19. p53 regulates cytoskeleton remodeling to suppress tumor progression.

    Science.gov (United States)

    Araki, Keigo; Ebata, Takahiro; Guo, Alvin Kunyao; Tobiume, Kei; Wolf, Steven John; Kawauchi, Keiko

    2015-11-01

    Cancer cells possess unique characteristics such as invasiveness, the ability to undergo epithelial-mesenchymal transition, and an inherent stemness. Cell morphology is altered during these processes and this is highly dependent on actin cytoskeleton remodeling. Regulation of the actin cytoskeleton is, therefore, important for determination of cell fate. Mutations within the TP53 (tumor suppressor p53) gene leading to loss or gain of function (GOF) of the protein are often observed in aggressive cancer cells. Here, we highlight the roles of p53 and its GOF mutants in cancer cell invasion from the perspective of the actin cytoskeleton; in particular its reorganization and regulation by cell adhesion molecules such as integrins and cadherins. We emphasize the multiple functions of p53 in the regulation of actin cytoskeleton remodeling in response to the extracellular microenvironment, and oncogene activation. Such an approach provides a new perspective in the consideration of novel targets for anti-cancer therapy.

  20. p53-Dependent suppression of genome instability in germ cells

    Energy Technology Data Exchange (ETDEWEB)

    Otozai, Shinji [Department of Otorhinolaryngology and Head and Neck Surgery, Osaka University School of Medicine, Osaka 565-0871 (Japan); Ishikawa-Fujiwara, Tomoko [Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Oda, Shoji [Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562 (Japan); Kamei, Yasuhiro [Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ryo, Haruko [Nomura Project, National Institute of Biomedical Innovation, Osaka 565-0085 (Japan); Sato, Ayuko [Department of Pathology, Hyogo College of Medicine, Hyogo 663-8501 (Japan); Nomura, Taisei [Nomura Project, National Institute of Biomedical Innovation, Osaka 565-0085 (Japan); Mitani, Hiroshi [Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562 (Japan); Tsujimura, Tohru [Department of Pathology, Hyogo College of Medicine, Hyogo 663-8501 (Japan); Inohara, Hidenori [Department of Otorhinolaryngology and Head and Neck Surgery, Osaka University School of Medicine, Osaka 565-0871 (Japan); Todo, Takeshi, E-mail: todo@radbio.med.osaka-u.ac.jp [Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University, B4, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2014-02-15

    Highlights: • Radiation-induced microsatellite instability (MSI) was investigated in medaka fish. • msh2{sup −/−} fish had a high frequency of spontaneous MSI. • p53{sup −/−} fish had a high frequency of radiation-induced MSI. • p53 and msh2 suppress MSI by different pathways: mismatch removal and apoptosis. - Abstract: Radiation increases mutation frequencies at tandem repeat loci. Germline mutations in γ-ray-irradiated medaka fish (Oryzias latipes) were studied, focusing on the microsatellite loci. Mismatch-repair genes suppress microsatellite mutation by directly removing altered sequences at the nucleotide level, whereas the p53 gene suppresses genetic alterations by eliminating damaged cells. The contribution of these two defense mechanisms to radiation-induced microsatellite instability was addressed. The spontaneous mutation frequency was significantly higher in msh2{sup −/−} males than in wild-type fish, whereas there was no difference in the frequency of radiation-induced mutations between msh2{sup −/−} and wild-type fish. By contrast, irradiated p53{sup −/−} fish exhibited markedly increased mutation frequencies, whereas their spontaneous mutation frequency was the same as that of wild-type fish. In the spermatogonia of the testis, radiation induced a high level of apoptosis both in wild-type and msh2{sup −/−} fish, but negligible levels in p53{sup −/−} fish. The results demonstrate that the msh2 and p53 genes protect genome integrity against spontaneous and radiation-induced mutation by two different pathways: direct removal of mismatches and elimination of damaged cells.

  1. p53-Dependent suppression of genome instability in germ cells

    International Nuclear Information System (INIS)

    Otozai, Shinji; Ishikawa-Fujiwara, Tomoko; Oda, Shoji; Kamei, Yasuhiro; Ryo, Haruko; Sato, Ayuko; Nomura, Taisei; Mitani, Hiroshi; Tsujimura, Tohru; Inohara, Hidenori; Todo, Takeshi

    2014-01-01

    Highlights: • Radiation-induced microsatellite instability (MSI) was investigated in medaka fish. • msh2 −/− fish had a high frequency of spontaneous MSI. • p53 −/− fish had a high frequency of radiation-induced MSI. • p53 and msh2 suppress MSI by different pathways: mismatch removal and apoptosis. - Abstract: Radiation increases mutation frequencies at tandem repeat loci. Germline mutations in γ-ray-irradiated medaka fish (Oryzias latipes) were studied, focusing on the microsatellite loci. Mismatch-repair genes suppress microsatellite mutation by directly removing altered sequences at the nucleotide level, whereas the p53 gene suppresses genetic alterations by eliminating damaged cells. The contribution of these two defense mechanisms to radiation-induced microsatellite instability was addressed. The spontaneous mutation frequency was significantly higher in msh2 −/− males than in wild-type fish, whereas there was no difference in the frequency of radiation-induced mutations between msh2 −/− and wild-type fish. By contrast, irradiated p53 −/− fish exhibited markedly increased mutation frequencies, whereas their spontaneous mutation frequency was the same as that of wild-type fish. In the spermatogonia of the testis, radiation induced a high level of apoptosis both in wild-type and msh2 −/− fish, but negligible levels in p53 −/− fish. The results demonstrate that the msh2 and p53 genes protect genome integrity against spontaneous and radiation-induced mutation by two different pathways: direct removal of mismatches and elimination of damaged cells

  2. p53-Mediated Molecular Control of Autophagy in Tumor Cells

    Directory of Open Access Journals (Sweden)

    Maria Mrakovcic

    2018-03-01

    Full Text Available Autophagy is an indispensable mechanism of the eukaryotic cell, facilitating the removal and renewal of cellular components and thereby balancing the cell’s energy consumption and homeostasis. Deregulation of autophagy is now regarded as one of the characteristic key features contributing to the development of tumors. In recent years, the suppression of autophagy in combination with chemotherapeutic treatment has been approached as a novel therapy in cancer treatment. However, depending on the type of cancer and context, interference with the autophagic machinery can either promote or disrupt tumorigenesis. Therefore, disclosure of the major signaling pathways that regulate autophagy and control tumorigenesis is crucial. To date, several tumor suppressor proteins and oncogenes have emerged as eminent regulators of autophagy whose depletion or mutation favor tumor formation. The mammalian cell “janitor” p53 belongs to one of these tumor suppressors that are most commonly mutated in human tumors. Experimental evidence over the last decade convincingly reports that p53 can act as either an activator or an inhibitor of autophagy depending on its subcellular localization and its mode of action. This finding gains particular significance as p53 deficiency or mutant variants of p53 that accumulate in the cytoplasm of tumor cells enable activation of autophagy. Accordingly, we recently identified p53 as a molecular hub that regulates autophagy and apoptosis in histone deacetylase inhibitor-treated uterine sarcoma cells. In light of this novel experimental evidence, in this review, we focus on p53 signaling as a mediator of the autophagic pathway in tumor cells.

  3. Overexpression of the E2F target gene CENPI promotes chromosome instability and predicts poor prognosis in estrogen receptor-positive breast cancer.

    Science.gov (United States)

    Thangavelu, Pulari U; Lin, Cheng-Yu; Vaidyanathan, Srividya; Nguyen, Thu H M; Dray, Eloise; Duijf, Pascal H G

    2017-09-22

    During cell division, chromosome segregation is facilitated by the mitotic checkpoint, or spindle assembly checkpoint (SAC), which ensures correct kinetochore-microtubule attachments and prevents premature sister-chromatid separation. It is well established that misexpression of SAC components on the outer kinetochores promotes chromosome instability (CIN) and tumorigenesis. Here, we study the expression of CENP-I, a key component of the HIKM complex at the inner kinetochores, in breast cancer, including ductal, lobular, medullary and male breast carcinomas. CENPI mRNA and protein levels are significantly elevated in estrogen receptor-positive (ER+) but not in estrogen receptor-negative (ER-) breast carcinoma. Well-established prognostic tests indicate that CENPI overexpression constitutes a powerful independent marker for poor patient prognosis and survival in ER+ breast cancer. We further demonstrate that CENPI is an E2F target gene. Consistently, it is overexpressed in RB1 -deficient breast cancers. However, CENP-I overexpression is not purely due to cell cycle-associated expression. In ER+ breast cancer cells, CENP-I overexpression promotes CIN, especially chromosome gains. In addition, in ER+ breast carcinomas the degree of CENPI overexpression is proportional to the level of aneuploidy and CENPI overexpression is one of the strongest markers for CIN identified to date. Our results indicate that overexpression of the inner kinetochore protein CENP-I promotes CIN and forecasts poor prognosis for ER+ breast cancer patients. These observations provide novel mechanistic insights and have important implications for breast cancer diagnostics and potentially therapeutic targeting.

  4. Tumor hypoxia, p53, and prognosis in cervical cancers

    International Nuclear Information System (INIS)

    Haensgen, Gabriele; Krause, Ulf; Becker, Axel; Stadler, Peter; Lautenschlaeger, Christine; Wohlrab, Wolfgang; Rath, Friedrich W.; Molls, Michael; Dunst, Juergen

    2001-01-01

    Background: The p53 protein is involved in the regulation of initiation of apoptosis. In vitro, p53-deficient cells do not respond to hypoxia with apoptosis as do p53-normal cells, and this may lead to a relative growth advantage of cells without a functioning p53 under hypoxia. On the basis of this hypothesis, a selection of cells with a functionally inactive p53 may occur in hypoxic tumors. The development of uterine cervical carcinomas is closely associated with infections of human papilloma viruses, which may cause a degradation of the tumor suppressor gene p53, resulting in a restriction of apoptosis. Thus, cervical cancers have often a functionally inactive p53. The purpose of our clinical study was therefore to investigate the association between p53, hypoxia, and prognosis in cervical cancers in which the oxygenation status can be determined by clinical methods. Material and Methods: Seventy patients with locally advanced squamous cell cervical cancer Stages IIB (n=14), IIIB (n=49), and IVA (n=7) were investigated in the period from 1996 through 1999. All were treated with definitive radiotherapy with curative intent by a combination of external radiotherapy plus high-dose-rate afterloading. Before therapy, tumor oxygenation was measured with a needle probe polarographically using the Eppendorf histograph. Hypoxic tumors were defined as those with pO 2 measurements below 5 mm Hg (HF5). Pretreatment biopsies were taken and analyzed immunohistologically for p53 protein expression with the DO-7 antibody. The DNA index was measured by flow cytometry. The statistical data analysis was done with SPSS 9.0 for Windows. Results: The 3-year overall survival was 55% for the whole group of patients. Clinical prognostic factors in a multivariate analysis were pretreatment hemoglobin level (3-year survival 62% for patients with a pretreatment hemoglobin ≥11 g/dl vs. 27% for hemoglobin <11 g/dl, p=0.006) and FIGO stage (Stage IIB: 65%; Stage IIIB: 60%; Stage IVA: 29%, p

  5. Super p53 for Treatment of Ovarian Cancer

    Science.gov (United States)

    2017-09-01

    System 3, Clontech) containing wt-p53, p53-CC, and ZsGreen (control) were made. Ad-ZsGreen was tested in ID8 cells, which showed very high expression...views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army...MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION / AVAILABILITY STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14

  6. P53 Protein Expression in Dental Follicle, Dentigerous Cyst, Odontogenic Keratocyst, and Inflammatory Subtypes of Cysts: An Immunohistochemical Study.

    Science.gov (United States)

    Fatemeh, Mashhadiabbas; Sepideh, Arab; Sara, Bagheri Seyedeh; Nazanin, Mahdavi

    2017-05-01

    An odontogenic keratocyst (OKC) is a developmental odontogenic cyst with aggressive clinical behavior. This cyst shows a different growth mechanism from the more common dentigerous cyst and now has been renamed as a keratocystic odontogenic tumor (KCOT). Inflammation can assist tumor growth via different mechanisms including dysregulation of the p53 gene. This study aims to assess and compare the expression of tumor suppressor gene p53 in inflamed and non-inflamed types of OKC and dentigerous cyst. Immunohistochemical expression of p53 was assessed in 14 cases of dental follicle, 34 cases of OKC (including 18 inflamed OKCs), and 31 cases of dentigerous cyst (including 16 inflamed cysts). The mean percentage of p53 positive cells was 0.7% in dental follicles, 5.4% in non-inflamed OKCs, 17.3% in inflamed OKCs, 1.2% in non-inflamed dentigerous cysts, and 2.2% in inflamed dentigerous cysts. The differences between the groups were statistically significant ( p < 0.050) except for the difference between inflamed and non-inflamed dentigerous cysts, and between dental follicle and non-inflamed dentigerous cyst. The difference in p53 expression in OKC and dentigerous cyst can explain their different growth mechanism and clinical behavior. Inflammation is responsible for the change in behavior of neoplastic epithelium of OKC via p53 overexpression.

  7. P53 Protein Expression in Dental Follicle, Dentigerous Cyst, Odontogenic Keratocyst, and Inflammatory Subtypes of Cysts: An Immunohistochemical Study

    Directory of Open Access Journals (Sweden)

    Mashhadiabbas Fatemeh

    2017-05-01

    Full Text Available Objectives: An odontogenic keratocyst (OKC is a developmental odontogenic cyst with aggressive clinical behavior. This cyst shows a different growth mechanism from the more common dentigerous cyst and now has been renamed as a keratocystic odontogenic tumor (KCOT. Inflammation can assist tumor growth via different mechanisms including dysregulation of the p53 gene. This study aims to assess and compare the expression of tumor suppressor gene p53 in inflamed and non-inflamed types of OKC and dentigerous cyst. Methods: Immunohistochemical expression of p53 was assessed in 14 cases of dental follicle, 34 cases of OKC (including 18 inflamed OKCs, and 31 cases of dentigerous cyst (including 16 inflamed cysts. Results: The mean percentage of p53 positive cells was 0.7% in dental follicles, 5.4% in non-inflamed OKCs, 17.3% in inflamed OKCs, 1.2% in non-inflamed dentigerous cysts, and 2.2% in inflamed dentigerous cysts. The differences between the groups were statistically significant (p < 0.050 except for the difference between inflamed and non-inflamed dentigerous cysts, and between dental follicle and non-inflamed dentigerous cyst. Conclusions: The difference in p53 expression in OKC and dentigerous cyst can explain their different growth mechanism and clinical behavior. Inflammation is responsible for the change in behavior of neoplastic epithelium of OKC via p53 overexpression.

  8. Prognostic Role of Serum Antibody Immunity to p53 Oncogenic Protein in Ovarian Cancer: A Systematic Review and a Meta-Analysis.

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    Marica Garziera

    Full Text Available Serum p53 autoantibodies (p53-AAbs are the product of an endogenous immune response against p53 overexpression driven by the ovarian tumour. The p53-AAbs are detectable only in a subset of patients. To date, the evidence of an association between the presence of p53-AAbs and ovarian cancer outcomes has been poorly investigated.A systematic literature search was performed to identify eligible studies investigating the association of serum p53-AAbs and overall survival (OS and disease free survival (DFS. Associations between presence of serum p53-AAbs and baseline tumour characteristics were also evaluated. Pooled hazard ratios (HRs and corresponding 95% confidence intervals (CI were computed to estimate the prognostic impact of serum p53-AAbs. Heterogeneity between studies was assessed.A total of 583 patients (7 studies for OS and 356 patients (4 studies for DFS were included in the meta-analysis. Presence of p53-AAbs was not associated to OS (pooled uni- multivariate HR = 1.09; 95% CI: 0.55-2.16, and a large heterogeneity was found. When only multivariate HRs were pooled together (4 studies, presence of p53-AAbs was significantly associated to a better OS (pooled HR = 0.57; 95% CI: 0.40-0.81, and no significant heterogeneity was observed. A reduced DFS was associated to p53-AAbs (pooled uni- multivariate HR = 1.37; 95% CI: 0.83-2.25, though not significantly and with a moderate heterogeneity.The prognostic significance of serum p53-AAbs in ovarian cancer was diverging according to uni or multivariate models used. Since the results of this work were based on only few investigations, large prospective studies are needed to better define the role of antibody immunity against p53.

  9. Epidemiology Study on P53 (Rs1614984 C>T Mutation in Cigarette Smokers

    Directory of Open Access Journals (Sweden)

    Dilshad Ahmad

    2017-05-01

    Full Text Available ABSTRACT Epidemiology data have established that smoking is a prime threat for the cancers, largely lung cancer. Single-nucleotide polymorphisms (SNPs,P53 SNPs have been found to be associated with the predisposition of different cancers. Their decreased expression is reported in breast and lung cancer patients. p53 (rs1614984 had been reported to be linked with the SNPs found associated with breast cancer. The primary aim of this study to determine the association of p53 variant rs1614984 with the cigarette smokers and smoking related cancers in smokers. Among the smokers, 38% were found with CC genotype, 55% were heterozygous CT and 7% were TT, respectively. The homozygous TT genotype was seen in lower percentage of smokers (7% when compared to non-smokers (8% whereas; Significant difference was not observed when encompassed by CC, CT and TT genotypes (χ2 = 4.892, p=0.087. However, CC vs CT genotype showed a significant difference between smokers and non-smokers (p=0.031, OR 1.447 (1.035-2.025 and the dominant model CC vs CT+TT was also significantly different among smoker and non-smokers (p=0.047, OR 1.39 (1.004-1.924. Furthermore, smokers are at the risk of developing variety of diseases including lung cancer. Our finding suggests a higher percentage of heterozygous CT genotype in smokers when compared to non-smokers. Therefore, this finding gives a clue that the transition mutation of C>T (rs1614984 may leads to the lung diseases including cancer in smokers. However, there will be a need of more extensive and elaborated study to set down the aspect of p53(rs1614984 C>T in lung cancer among smokers.

  10. Synergistic effect of p53 on TSA-induced stanniocalcin 1 expression in human nasopharyngeal carcinoma cells, CNE2.

    Science.gov (United States)

    Ching, L Y; Yeung, Bonnie H Y; Wong, Chris K C

    2012-06-01

    Human stanniocalcin 1 (STC1) has recently been identified as a putative protein factor involved in cellular apoptosis. The use of histone deacetylase inhibitor (i.e. trichostatin A (TSA)) and doxorubicin (Dox) is one of the common treatment methods to induce apoptosis in human cancer cells. A study on TSA and Dox-mediated apoptosis may shed light on the regulation and function of STC1 in cancer treatment. In this study, TSA and Dox cotreatment in human nasopharyngeal carcinoma cells (CNE2) elicited synergistic effects on STC1 gene expression and cellular apoptosis. An activation of p53 (TP53) transcriptional activity in Dox- or Dox+TSA-treated cells was revealed by the increased expression levels of p53 mRNA/protein as well as p53-driven luciferase activities. To elucidate the possible involvement of p53 in STC1 gene transcription, a vector expressing wild-type or dominant negative (DN) p53 was transiently transfected into the cells. Both STC1 promoter luciferase constructs and chromatin immunoprecipitation assays did not support the direct role of p53 in STC1 gene transactivation. However, the synergistic effects of p53 on the induction of NF-κB phosphorylation and the recruitment of acetylated histone H3 in STC1 promoter were observed in TSA-cotreated cells. The overexpression of exogenous STC1 sensitized apoptosis in Dox-treated cells. Taken together, this study provides data to show the cross talk of NF-κB, p53, and histone protein in the regulation of STC1 expression and function.

  11. A Chimeric Protein PTEN-L-p53 Enters U251 Cells to Repress Proliferation and Invasion.

    Science.gov (United States)

    Xiao, Man; An, Yang; Wang, Fengling; Yao, Chao; Zhang, Chu; Xin, Junfang; Duan, Yongjian; Zhao, Xiaofang; Fang, Na; Ji, Shaoping

    2018-05-23

    PTEN, a well-known tumor suppressor, dephosphorylates PIP3 and inhibits AKT activity. A translational variant of PTEN has been identified and termed PTEN-Long (PTEN-L). The additional 173 amino acids (PTEN-L leader) at the N-terminal constitute a potential signal peptide. Differing from canonical PTEN, PTEN-L is secreted into the extracellular fluid and re-enters recipient cells, playing the similar roles as PTEN in vivo and in vitro. This character confers the PTEN-L a therapeutic ability via directly protein delivering instead of traditional DNA and RNA vector options. In the present study, we employed PTEN-L leader to assemble a fusion protein, PTEN-L-p53, inosculated with the transcriptional regulator TP53, which is another powerful tumor suppressor. We overexpressed PTEN-L-p53 in HEK293T cells and detected it in both the cytoplasm and nucleus. Subsequently, we found that PTEN-L-p53 was secreted outside of the cells and detected in the culture media by immunoblotting. Furthermore, we demonstrated that PTEN-L-p53 freely entered the cells and suppressed the viability of U251cells (p53 R273H , a cell line with p53 R273H-mutation). PTEN-L-p53 is composed of endogenous protein/peptide bearing low immunogenicity, and only the junction region between PTEN-L leader and p53 can act as a new immune epitope. Accordingly, this fusion protein can potentially be used as a therapeutic option for TP53-abnormality cancers. Copyright © 2018. Published by Elsevier Inc.

  12. 1800MHz Microwave Induces p53 and p53-Mediated Caspase-3 Activation Leading to Cell Apoptosis In Vitro.

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    Fuqiang Xing

    Full Text Available Recent studies have reported that exposure of mammalian cells to microwave radiation may have adverse effects such as induction of cell apoptosis. However, the molecular mechanisms underlying microwave induced mammalian cell apoptosis are not fully understood. Here, we report a novel mechanism: exposure to 1800MHz microwave radiation induces p53-dependent cell apoptosis through cytochrome c-mediated caspase-3 activation pathway. We first measured intensity of microwave radiation from several electronic devices with an irradiation detector. Mouse NIH/3T3 and human U-87 MG cells were then used as receivers of 1800MHz electromagnetic radiation (EMR at a power density of 1209 mW/m2. Following EMR exposure, cells were analyzed for viability, intracellular reactive oxygen species (ROS generation, DNA damage, p53 expression, and caspase-3 activity. Our analysis revealed that EMR exposure significantly decreased viability of NIH/3T3 and U-87 MG cells, and increased caspase-3 activity. ROS burst was observed at 6 h and 48 h in NIH/3T3 cells, while at 3 h in U-87 MG cells. Hoechst 33258 staining and in situ TUNEL assay detected that EMR exposure increased DNA damage, which was significantly restrained in the presence of N-acetyl-L-cysteine (NAC, an antioxidant. Moreover, EMR exposure increased the levels of p53 protein and p53 target gene expression, promoted cytochrome c release from mitochondrion, and increased caspase-3 activity. These events were inhibited by pretreatment with NAC, pifithrin-α (a p53 inhibitor and caspase inhibitor. Collectively, our findings demonstrate, for the first time, that 1800MHz EMR induces apoptosis-related events such as ROS burst and more oxidative DNA damage, which in turn promote p53-dependent caspase-3 activation through release of cytochrome c from mitochondrion. These findings thus provide new insights into physiological mechanisms underlying microwave-induced cell apoptosis.

  13. The Hunger Games: p53 regulates metabolism upon serine starvation.

    Science.gov (United States)

    Tavana, Omid; Gu, Wei

    2013-02-05

    Cancer cells reprogram their metabolism to support a high proliferative rate. A new study shows that, upon serine starvation, the tumor suppressor p53 activates p21 to shift metabolic flux from purine biosynthesis to glutathione production, which enhances cellular proliferation and viability by combating ROS (Maddocks et al., 2013). Copyright © 2013 Elsevier Inc. All rights reserved.

  14. p53 expression in colorectal carcinoma in relation to ...

    African Journals Online (AJOL)

    Haematoxylin and eosin stain was used for evaluation of histological types and degree of differentiation of the tumors. Topography of the tumors and demographic data were obtained from accompanying histological request forms. Results: Out of 109 patient\\'s tissue blocks that were studied, 61 cases (56%) expressed p53 ...

  15. Cellular inactivation of nitric oxide induces p53-dependent ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research August 2016; 15 (8): 1595-1603 ... Cellular inactivation of nitric oxide induces p53-dependent apoptosis in ... apoptosis induced by a selective iNOS inhibitor, N-[(3-aminomethyl) benzyl] acetamidine (1400W), .... and nitrate. ... Nitrite production was measured in culture media.

  16. HAMLET triggers apoptosis but tumor cell death is independent of caspases, Bcl-2 and p53.

    Science.gov (United States)

    Hallgren, O; Gustafsson, L; Irjala, H; Selivanova, G; Orrenius, S; Svanborg, C

    2006-02-01

    HAMLET (Human alpha-lactalbumin Made Lethal to Tumor cells) triggers selective tumor cell death in vitro and limits tumor progression in vivo. Dying cells show features of apoptosis but it is not clear if the apoptotic response explains tumor cell death. This study examined the contribution of apoptosis to cell death in response to HAMLET. Apoptotic changes like caspase activation, phosphatidyl serine externalization, chromatin condensation were detected in HAMLET-treated tumor cells, but caspase inhibition or Bcl-2 over-expression did not prolong cell survival and the caspase response was Bcl-2 independent. HAMLET translocates to the nuclei and binds directly to chromatin, but the death response was unrelated to the p53 status of the tumor cells. p53 deletions or gain of function mutations did not influence the HAMLET sensitivity of tumor cells. Chromatin condensation was partly caspase dependent, but apoptosis-like marginalization of chromatin was also observed. The results show that tumor cell death in response to HAMLET is independent of caspases, p53 and Bcl-2 even though HAMLET activates an apoptotic response. The use of other cell death pathways allows HAMLET to successfully circumvent fundamental anti-apoptotic strategies that are present in many tumor cells.

  17. Nucleolus-derived mediators in oncogenic stress response and activation of p53-dependent pathways.

    Science.gov (United States)

    Stępiński, Dariusz

    2016-08-01

    Rapid growth and division of cells, including tumor ones, is correlated with intensive protein biosynthesis. The output of nucleoli, organelles where translational machineries are formed, depends on a rate of particular stages of ribosome production and on accessibility of elements crucial for their effective functioning, including substrates, enzymes as well as energy resources. Different factors that induce cellular stress also often lead to nucleolar dysfunction which results in ribosome biogenesis impairment. Such nucleolar disorders, called nucleolar or ribosomal stress, usually affect cellular functioning which in fact is a result of p53-dependent pathway activation, elicited as a response to stress. These pathways direct cells to new destinations such as cell cycle arrest, damage repair, differentiation, autophagy, programmed cell death or aging. In the case of impaired nucleolar functioning, nucleolar and ribosomal proteins mediate activation of the p53 pathways. They are also triggered as a response to oncogenic factor overexpression to protect tissues and organs against extensive proliferation of abnormal cells. Intentional impairment of any step of ribosome biosynthesis which would direct the cells to these destinations could be a strategy used in anticancer therapy. This review presents current knowledge on a nucleolus, mainly in relation to cancer biology, which is an important and extremely sensitive element of the mechanism participating in cellular stress reaction mediating activation of the p53 pathways in order to counteract stress effects, especially cancer development.

  18. Apoptosis in spermatogonia irradiated P53 null mice

    International Nuclear Information System (INIS)

    Streit-Bianchi, M.; Hendry, J.H.; Roberts, S.A.; Morris, J.D.; Durgaryan, A.A.

    2007-01-01

    Complete text of publication follows. The exposure of germ cells to ionizing radiations is of concern both from high-dose therapeutic exposures and from low doses causing deleterious trans-generational mutations. P53 protein plays an important role in cellular damage and is expressed in the testis normally during meiosis, its expression being localised to the preleptotene and early/mid pachytene spermatocytes. P53 null mice, heterozygotes possessing a 129 Sv/C57BL6 genetic background and B6D2F1 mice have been irradiated to 1 and 2 Gy single doses. Fractionated exposures of 1+1 Gy at 4 hours interval were also carried out. Apoptosis induction, spermatogonia and spermatocytes survival were assessed by microscope analysis of histological samples at 4 to 96 hours after irradiation in time-course experiments. The same end-points were also assessed at 72 and 96 hours after irradiation to single doses in the region between 20cGy to 2Gy. A dose dependent level of p53 expression was observed at 4 hours after irradiation to 1 and 2 Gy which returned to normal level by 24 hours. Our data support a two process mode of apoptosis with a first wave around 12 hours followed by a second wave at 2-3 days. The first wave apoptosis is substantially reduced in p53 null mice whereas the second wave is reduced in B6D2F1 mice. The initial increase in apoptosis was delayed in some stages of the of germ cells development which were identified by the spermatids shape. Clear correlation exists between apoptosis and survival assessed in stage XI-XII Tubules 72 hours after irradiation. The data are in agreement with other data in literature indicating that irradiated spermatogonia die through apoptosis. The lack of apoptosis observed in p53 null mice results in a very high survival rate of daughter cells assessed later. Theses spermatocytes and the following progenitor cells are likely to carry mutations as most will not die in the smaller second wave of apoptosis observed 3 days after

  19. Autophagy Protects from Trastuzumab-Induced Cytotoxicity in HER2 Overexpressing Breast Tumor Spheroids.

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    Cristina E Rodríguez

    Full Text Available Multicellular tumor spheroids represent a 3D in vitro model that mimics solid tumor essential properties including assembly and development of extracellular matrix and nutrient, oxygen and proliferation gradients. In the present study, we analyze the impact of 3D spatial organization of HER2-overexpressing breast cancer cells on the response to Trastuzumab. We cultured human mammary adenocarcinoma cell lines as spheroids with the hanging drop method and we observed a gradient of proliferating, quiescent, hypoxic, apoptotic and autophagic cells towards the inner core. This 3D organization decreased Trastuzumab sensitivity of HER2 over-expressing cells compared to monolayer cell cultures. We did not observe apoptosis induced by Trastuzumab but found cell arrest in G0/G1 phase. Moreover, the treatment downregulated the basal apoptosis only found in tumor spheroids, by eliciting protective autophagy. We were able to increase sensitivity to Trastuzumab by autophagy inhibition, thus exposing the interaction between apoptosis and autophagy. We confirmed this result by developing a resistant cell line that was more sensitive to autophagy inhibition than the parental BT474 cells. In summary, the development of Trastuzumab resistance relies on the balance between death and survival mechanisms, characteristic of 3D cell organization. We propose the use of spheroids to further improve the understanding of Trastuzumab antitumor activity and overcome resistance.

  20. Epidermal growth factor receptor overexpression and outcomes in early breast cancer: A systematic review and a meta-analysis.

    Science.gov (United States)

    Gonzalez-Conchas, Galileo A; Rodriguez-Romo, Laura; Hernandez-Barajas, David; Gonzalez-Guerrero, Juan F; Rodriguez-Fernandez, Ivan A; Verdines-Perez, Adrian; Templeton, Arnoud J; Ocana, Alberto; Seruga, Bostjan; Tannock, Ian F; Amir, Eitan; Vera-Badillo, Francisco E

    2018-01-01

    The epidermal growth factor receptor (EGFR) is a member of the ErbB family of membrane tyrosine-kinase receptors. Studies exploring the prognostic role of EGFR-overexpression in early breast cancer have shown variable results, and the true prognostic value of EGFR is unknown. A systematic review of identified publications exploring the association between EGFR-overexpression (as defined from different techniques and cut-offs) and outcomes [disease-free (DFS) and, overall survival (OS)] in women with early breast cancer. The hazard ratios (HR) for DFS and OS were weighted and pooled in a meta-analysis using generic inverse variance and random effects modeling. Fifty-three studies comprising 21,418 women were included. EGFR-overexpression was found in 27% of the patients. Primary analysis included studies reporting HRs from multivariable analyses (10 studies including 4857 patients with HRs for OS and 17 studies comprising 8747 patients with HRs for DFS), EGFR-overexpression was associated with worse OS (HR 1.98, 95% CI: 1.59-2.47, p overexpression on DFS was greater in women with triple negative tumors compared to women with non-triple negative tumors (HR 2.35 versus HR 1.45, respectively; p = .01). Analysis looking at odd ratios for both 5-year and 10-year for DFS and OS showed similar results. EGFR-overexpression appears to be associated with reduced OS and DFS in women with early breast cancer. Patients with triple negative and EGFR-overexpression have poorer OS and DFS than those with triple negative tumors and normal EGFR expression. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Heba Bassiony

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

  2. The structure formed by inverted repeats in p53 response elements determines the transactivation activity of p53 protein

    Czech Academy of Sciences Publication Activity Database

    Brázda, Václav; Čechová, Jana; Battistin, M.; Coufal, Jan; Jagelská, Eva; Raimondi, I.; Inga, A.

    2017-01-01

    Roč. 483, č. 1 (2017), s. 516-521 ISSN 0006-291X R&D Projects: GA ČR GA15-21855S Institutional support: RVO:68081707 Keywords : tumor-suppressor p53 * cruciform structures * dna-conformation Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 2.466, year: 2016

  3. Brain metastases in patients who receive trastuzumab-containing chemotherapy for HER2-overexpressing metastatic breast cancer

    International Nuclear Information System (INIS)

    Ono, Makiko; Ando, Masashi; Yunokawa, Mayu

    2009-01-01

    Recently, a high rate of brain metastases has been reported among patients with human epidermal growth factor receptor (HER2)-overexpressing metastatic breast cancer who were treated with trastuzumab. The present study examined risk factors for the development of brain metastasis in patients with HER2-overexpressing breast cancer who were treated with trastuzumab. We retrospectively reviewed 204 patients with HER-2-overexpressing breast cancer who were treated with a trastuzumab-containing regimen between 1999 and 2006. Patients with clinical symptoms were diagnosed as having brain metastases when brain magnetic resonance imaging (MRI) or a computed tomography (CT) scan revealed positive findings for brain metastases. The median follow-up time of this cohort was 53.6 months. Among the patients who received a trastuzumab-containing regimen, 74 patients (36.3%) developed brain metastases. The median survival from the diagnosis of brain metastases was 13.5 months (95% confidence interval [CI], 12.2-14.7 months). The median time interval between the beginning of trastuzumab treatment and the diagnosis of brain metastases was 13.6 months (range, 0.0-45.8 months). Among patients with brain metastases, the median overall survival period was 39 months. A multivariate logistic regression analysis showed that age (≤50 years), recurrent breast cancer, and liver metastases were significant risk factors for the development of brain metastases. Patients with HER2-overexpressing breast cancer treated with trastuzumab had a high incidence of brain metastases (36.3%). Routine screening for brain metastases 1 year after the start of trastuzumab treatment, may be warranted in younger patients (≤50 years) who had recurrent breast cancer with liver metastases. (author)

  4. Differential sensitivity of p53+ and p53- cells to caffeine-induced radiosensitization and override of G2 delay

    International Nuclear Information System (INIS)

    Powell, S.N.; DeFrank, J.S.; Connell, P.; Eogan, M.; Preffer, F.; Dombkowski, D.; Tang, W.; Friend, S.H.

    1995-01-01

    Purpose: Most drug discovery efforts have focused on finding new DNA damaging agents to kill tumor cells preferentially. An alternative approach is to find ways to increase tumor specific killing by modifying tumor specific responses to that damage. We asked whether cells lacking the G1/S arrest in response to X-rays are more sensitive to X-ray damage when treated with agents that override G2/M arrest. Materials and Methods: Mouse embryonic fibroblasts genetically matched to be (+/+) or (-/-) p53 and rat embryonic fibroblasts (REF) made (+) or (-) for wild-type p53 function by transfection were irradiated with and without caffeine, a known checkpoint inhibitor. Caffeine treatment was maintained for 24 hours from 1 hour prior to irradiation. Cell survival following ionizing radiation was measured by clonogenic assay. For cell-cycle analysis, cells were in exponential asynchronous growth at the time of irradiation. The proportion of cells in G1, S and G2/M phases of the cell cycle were recorded immediately before and following irradiation and subsequently at 3,6,9,12,24 and 48 hours following irradiation. Results: Caffeine was found to cause radiosensitzation at low dose (0.5mM) in (-/-) cells but not in (+/+) cells. The sensitization enhancement ratio (SER) was 1.45 at 0.1 survival and 1.56 at 0.01 survival. At this dose of caffeine, this SER reflected therapeutic gain as there was no detectable effect on (+/+) cells. At 1mM caffeine, sensitization of (-/-) cells was 1.77, but (+/+) cells now also showed sensitization (SER=1.25). In (-/-) cells at 0.1mM caffeine the SER was 1.5 at 0.01 survival. The transfected REF cells (functionally null for p53) also exhibited caffeine-induced radiosensitization at both 0.5 and 2mM caffeine with a SER 1.45 for 2mM at 0.1 survival. No significant sensitization could be demonstrated for REF cells at the same doses of caffeine. The REF cells, with wild-type p53, transfected with pCMVneo alone showed no change in radiosensitivity or

  5. Transactivation of bad by vorinostat-induced acetylated p53 enhances doxorubicin-induced cytotoxicity in cervical cancer cells.

    Science.gov (United States)

    Lee, Sook-Jeong; Hwang, Sung-Ook; Noh, Eun Joo; Kim, Dong-Uk; Nam, Miyoung; Kim, Jong Hyeok; Nam, Joo Hyun; Hoe, Kwang-Lae

    2014-02-14

    Vorinostat (VOR) has been reported to enhance the cytotoxic effects of doxorubicin (DOX) with fewer side effects because of the lower DOX dosage in breast cancer cells. In this study, we investigated the novel mechanism underlying the synergistic cytotoxic effects of VOR and DOX co-treatment in cervical cancer cells HeLa, CaSki and SiHa cells. Co-treatment with VOR and DOX at marginal doses led to the induction of apoptosis through caspase-3 activation, poly (ADP-ribose) polymerase cleavage and DNA micronuclei. Notably, the synergistic growth inhibition induced by the co-treatment was attributed to the upregulation of the pro-apoptotic protein Bad, as the silencing of Bad expression using small interfering RNA (siRNA) abolished the phenomenon. As siRNA against p53 did not result in an increase in acetylated p53 and the consequent upregulation of Bad, the observed Bad upregulation was mediated by acetylated p53. Moreover, a chromatin immunoprecipitation analysis showed that the co-treatment of HeLa cells with VOR and DOX increased the recruitment of acetylated p53 to the bad promoter, with consequent bad transactivation. Conversely, C33A cervical cancer cells containing mutant p53 co-treated with VOR and DOX did not exhibit Bad upregulation, acetylated p53 induction or consequent synergistic growth inhibition. Together, the synergistic growth inhibition of cervical cancer cell lines induced by co-treatment with VOR and DOX can be attributed to the upregulation of Bad, which is induced by acetylated p53. These results show for the first time that the acetylation of p53, rather than histones, is a mechanism for the synergistic growth inhibition induced by VOR and DOX co-treatments.

  6. Abrogation of Wip1 expression by RITA-activated p53 potentiates apoptosis induction via activation of ATM and inhibition of HdmX

    Science.gov (United States)

    Spinnler, C; Hedström, E; Li, H; de Lange, J; Nikulenkov, F; Teunisse, A F A S; Verlaan-de Vries, M; Grinkevich, V; Jochemsen, A G; Selivanova, G

    2011-01-01

    Inactivation of the p53 tumour suppressor, either by mutation or by overexpression of its inhibitors Hdm2 and HdmX is the most frequent event in cancer. Reactivation of p53 by targeting Hdm2 and HdmX is therefore a promising strategy for therapy. However, Hdm2 inhibitors do not prevent inhibition of p53 by HdmX, which impedes p53-mediated apoptosis. Here, we show that p53 reactivation by the small molecule RITA leads to efficient HdmX degradation in tumour cell lines of different origin and in xenograft tumours in vivo. Notably, HdmX degradation occurs selectively in cancer cells, but not in non-transformed cells. We identified the inhibition of the wild-type p53-induced phosphatase 1 (Wip1) as the major mechanism important for full engagement of p53 activity accomplished by restoration of the ataxia telangiectasia mutated (ATM) kinase-signalling cascade, which leads to HdmX degradation. In contrast to previously reported transactivation of Wip1 by p53, we observed p53-dependent repression of Wip1 expression, which disrupts the negative feedback loop conferred by Wip1. Our study reveals that the depletion of both HdmX and Wip1 potentiates cell death due to sustained activation of p53. Thus, RITA is an example of a p53-reactivating drug that not only blocks Hdm2, but also inhibits two important negative regulators of p53 – HdmX and Wip1, leading to efficient elimination of tumour cells. PMID:21546907

  7. Abrogation of Wip1 expression by RITA-activated p53 potentiates apoptosis induction via activation of ATM and inhibition of HdmX.

    Science.gov (United States)

    Spinnler, C; Hedström, E; Li, H; de Lange, J; Nikulenkov, F; Teunisse, A F A S; Verlaan-de Vries, M; Grinkevich, V; Jochemsen, A G; Selivanova, G

    2011-11-01

    Inactivation of the p53 tumour suppressor, either by mutation or by overexpression of its inhibitors Hdm2 and HdmX is the most frequent event in cancer. Reactivation of p53 by targeting Hdm2 and HdmX is therefore a promising strategy for therapy. However, Hdm2 inhibitors do not prevent inhibition of p53 by HdmX, which impedes p53-mediated apoptosis. Here, we show that p53 reactivation by the small molecule RITA leads to efficient HdmX degradation in tumour cell lines of different origin and in xenograft tumours in vivo. Notably, HdmX degradation occurs selectively in cancer cells, but not in non-transformed cells. We identified the inhibition of the wild-type p53-induced phosphatase 1 (Wip1) as the major mechanism important for full engagement of p53 activity accomplished by restoration of the ataxia telangiectasia mutated (ATM) kinase-signalling cascade, which leads to HdmX degradation. In contrast to previously reported transactivation of Wip1 by p53, we observed p53-dependent repression of Wip1 expression, which disrupts the negative feedback loop conferred by Wip1. Our study reveals that the depletion of both HdmX and Wip1 potentiates cell death due to sustained activation of p53. Thus, RITA is an example of a p53-reactivating drug that not only blocks Hdm2, but also inhibits two important negative regulators of p53 - HdmX and Wip1, leading to efficient elimination of tumour cells.

  8. The nucleolar SUMO-specific protease SMT3IP1/SENP3 attenuates Mdm2-mediated p53 ubiquitination and degradation

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Tamotsu, E-mail: nishida@gene.mie-u.ac.jp [Department of Human Functional Genomics, Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507 (Japan); Yamada, Yoshiji [Department of Human Functional Genomics, Life Science Research Center, Mie University, 1577 Kurima-machiya, Tsu 514-8507 (Japan)

    2011-03-11

    Research highlights: {yields} SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. {yields} SMT3IP1 competes with p53 for binding to the central acidic domain of Mdm2. {yields} SMT3IP1 binding to Mdm2 inhibits Mdm2-mediated p53 ubiquitination and degradation. {yields} We postulate that SMT3IP1 acts as a new regulator of the p53-Mdm2 pathway. -- Abstract: SUMO (small ubiquitin-like modifier) modification plays multiple roles in several cellular processes. Sumoylation is reversibly regulated by SUMO-specific proteases. SUMO-specific proteases have recently been implicated in cell proliferation and early embryogenesis, but the underlying mechanisms remain unknown. Here, we show that a nucleolar SUMO-specific protease, SMT3IP1/SENP3, controls the p53-Mdm2 pathway. We found that SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. Overexpression of SMT3IP1 in cells resulted in the accumulation of Mdm2 in the nucleolus and increased stability of the p53 protein. In addition, SMT3IP1 bound to the acidic domain of Mdm2, which also mediates the p53 interaction, and competed with p53 for binding. Increasing expression of SMT3IP1 suppressed Mdm2-mediated p53 ubiquitination and subsequent proteasomal degradation. Interestingly, the desumoylation activity of SMT3IP1 was not necessary for p53 stabilization. These results suggest that SMT3IP1 is a new regulator of the p53-Mdm2 pathway.

  9. The nucleolar SUMO-specific protease SMT3IP1/SENP3 attenuates Mdm2-mediated p53 ubiquitination and degradation

    International Nuclear Information System (INIS)

    Nishida, Tamotsu; Yamada, Yoshiji

    2011-01-01

    Research highlights: → SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. → SMT3IP1 competes with p53 for binding to the central acidic domain of Mdm2. → SMT3IP1 binding to Mdm2 inhibits Mdm2-mediated p53 ubiquitination and degradation. → We postulate that SMT3IP1 acts as a new regulator of the p53-Mdm2 pathway. -- Abstract: SUMO (small ubiquitin-like modifier) modification plays multiple roles in several cellular processes. Sumoylation is reversibly regulated by SUMO-specific proteases. SUMO-specific proteases have recently been implicated in cell proliferation and early embryogenesis, but the underlying mechanisms remain unknown. Here, we show that a nucleolar SUMO-specific protease, SMT3IP1/SENP3, controls the p53-Mdm2 pathway. We found that SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. Overexpression of SMT3IP1 in cells resulted in the accumulation of Mdm2 in the nucleolus and increased stability of the p53 protein. In addition, SMT3IP1 bound to the acidic domain of Mdm2, which also mediates the p53 interaction, and competed with p53 for binding. Increasing expression of SMT3IP1 suppressed Mdm2-mediated p53 ubiquitination and subsequent proteasomal degradation. Interestingly, the desumoylation activity of SMT3IP1 was not necessary for p53 stabilization. These results suggest that SMT3IP1 is a new regulator of the p53-Mdm2 pathway.

  10. Reversible p53 inhibition prevents cisplatin ototoxicity without blocking chemotherapeutic efficacy.

    Science.gov (United States)

    Benkafadar, Nesrine; Menardo, Julien; Bourien, Jérôme; Nouvian, Régis; François, Florence; Decaudin, Didier; Maiorano, Domenico; Puel, Jean-Luc; Wang, Jing

    2017-01-01

    Cisplatin is a widely used chemotherapy drug, despite its significant ototoxic side effects. To date, the mechanism of cisplatin-induced ototoxicity remains unclear, and hearing preservation during cisplatin-based chemotherapy in patients is lacking. We found activation of the ATM-Chk2-p53 pathway to be a major determinant of cisplatin ototoxicity. However, prevention of cisplatin-induced ototoxicity is hampered by opposite effects of ATM activation upon sensory hair cells: promoting both outer hair cell death and inner hair cell survival. Encouragingly, however, genetic or pharmacological ablation of p53 substantially attenuated cochlear cell apoptosis, thus preserving hearing. Importantly, systemic administration of a p53 inhibitor in mice bearing patient-derived triple-negative breast cancer protected auditory function, without compromising the anti-tumor efficacy of cisplatin. Altogether, these findings highlight a novel and effective strategy for hearing protection in cisplatin-based chemotherapy. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  11. p53 protects against genome instability following centriole duplication failure

    Science.gov (United States)

    Lambrus, Bramwell G.; Uetake, Yumi; Clutario, Kevin M.; Daggubati, Vikas; Snyder, Michael; Sluder, Greenfield

    2015-01-01

    Centriole function has been difficult to study because of a lack of specific tools that allow persistent and reversible centriole depletion. Here we combined gene targeting with an auxin-inducible degradation system to achieve rapid, titratable, and reversible control of Polo-like kinase 4 (Plk4), a master regulator of centriole biogenesis. Depletion of Plk4 led to a failure of centriole duplication that produced an irreversible cell cycle arrest within a few divisions. This arrest was not a result of a prolonged mitosis, chromosome segregation errors, or cytokinesis failure. Depleting p53 allowed cells that fail centriole duplication to proliferate indefinitely. Washout of auxin and restoration of endogenous Plk4 levels in cells that lack centrioles led to the penetrant formation of de novo centrioles that gained the ability to organize microtubules and duplicate. In summary, we uncover a p53-dependent surveillance mechanism that protects against genome instability by preventing cell growth after centriole duplication failure. PMID:26150389

  12. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, Suthakar, E-mail: s.ganapathy@neu.edu [Center for Drug Development, Northeastern University, Boston (United States); Li, Ping [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Fagman, Johan [The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Yu, Tianqi; Lafontant, Jean [Center for Drug Development, Northeastern University, Boston (United States); Zhang, Guojun [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); Chen, Changyan [Center for Drug Development, Northeastern University, Boston (United States); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden)

    2016-09-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  13. 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...... tumors from smokers and 13 of 40 (33%) tumors from lifetime nonsmokers. Overall, 13 of the 50 (26%) total point mutations discovered in this and previous work were G:C-->C:G transversions, a relatively rare mutational type in human tumors. In six tumors, identical AGA (Arg)-->ACA (Thr) point mutations...... double mutations, four of which were tandem mutations on the same allele. No double mutations were found in tumors from nonsmoking patients. None of the mutations in smokers were G:C-->T:A transversions, which would be anticipated for exposure to the suspected cigarette smoke carcinogen 4-aminobiphenyl...

  14. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    International Nuclear Information System (INIS)

    Ganapathy, Suthakar; Li, Ping; Fagman, Johan; Yu, Tianqi; Lafontant, Jean; Zhang, Guojun; Chen, Changyan

    2016-01-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  15. COX-2 and p53 in human sinonasal cancer

    DEFF Research Database (Denmark)

    Holmila, Reetta; Cyr, Diane; Luce, Danièle

    2008-01-01

    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...... to development of cancer. Many signals that activate COX-2 also induce tumor suppressor p53, a transcription factor central in cellular stress response. We investigated COX-2 and p53 expressions by immunohistochemistry in 50 SNCs (23 adenocarcinomas, and 27 squamous cell carcinomas (SCC); 48 analyzed for COX-2...... displayed adenocarcinoma. COX-2 was expressed at higher levels in adenocarcinoma as compared to SSC (p COX-2 expression showed significant association with occupational exposure to wood dust (p = 0.024), and with nonsmoking status (p = 0.001). No statistically significant associations between...

  16. Super p53 for Treatment of Ovarian Cancer

    Science.gov (United States)

    2017-09-01

    position, policy or decision unless so designated by other documentation. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public...a lead construct. Technical skills gained in the proposal include cell culture , transfections, microscopy, apoptosis assays, transcriptional assays...experiments complete 100% (DOD) Specific Aim 2: Deliver super p53 DNA with advanced polymeric systems alone and in combination with CPTX first in vitro

  17. p53 and ARF: Unexpected players in autophagy

    OpenAIRE

    Balaburski, Gregor M.; Hontz, Robert D.; Murphy, Maureen E.

    2010-01-01

    p53 and ARF are well-established tumor suppressor proteins that function together in the negative regulation of cancer. Recently, both of these proteins were found to play surprising roles in autophagy. Autophagy (“self-eating”) is a critical response of eukaryotic cells to metabolic and other stress. During this process, portions of the cytosol are sequestered into characteristic double membrane vesicles that are delivered to the lysosome for degradation, leading to the release of free amino...

  18. Non-Canonical Cell Death Induced by p53

    Directory of Open Access Journals (Sweden)

    Atul Ranjan

    2016-12-01

    Full Text Available Programmed cell death is a vital biological process for multicellular organisms to maintain cellular homeostasis, which is regulated in a complex manner. Over the past several years, apart from apoptosis, which is the principal mechanism of caspase-dependent cell death, research on non-apoptotic forms of programmed cell death has gained momentum. p53 is a well characterized tumor suppressor that controls cell proliferation and apoptosis and has also been linked to non-apoptotic, non-canonical cell death mechanisms. p53 impacts these non-canonical forms of cell death through transcriptional regulation of its downstream targets, as well as direct interactions with key players involved in these mechanisms, in a cell type- or tissue context-dependent manner. In this review article, we summarize and discuss the involvement of p53 in several non-canonical modes of cell death, including caspase-independent apoptosis (CIA, ferroptosis, necroptosis, autophagic cell death, mitotic catastrophe, paraptosis, and pyroptosis, as well as its role in efferocytosis which is the process of clearing dead or dying cells.

  19. Electrophoretic detection of protein p53 in human leukocytes

    International Nuclear Information System (INIS)

    Paponov, V.D.; Kupsik, E.G.; Shcheglova, E.G.; Yarullin, N.N.

    1986-01-01

    The authors have found an acid-soluble protein with mol. wt. of about 53 kD in peripheral blood leukocytes of persons with Down's syndrome. It was present in different quantities in all 20 patients tested, but was virtually not discovered in 12 healthy blood donors. This paper determines the possible identity of this protein with protein p53 from mouse ascites carcinoma by comparing their electrophoretic mobilities, because the accuracy of electrophoretic determination of the molecular weight of proteins is not sufficient to identify them. The paper also describes experiments to detect a protein with electrophoretic mobility identical with that of a protein in the leukocytes of patients with Down's syndrome in leukocytes of patients with leukemia. To discover if protein p53 is involved in cell proliferation, the protein composition of leukocytes from healthy blood donors, cultured in the presence and absence of phytohemagglutinin (PHA), was compared. Increased incorporation of H 3-thymidine by leukocytes of patients with Down's syndrome is explained by the presence of a population of immature leukocytes actively synthesizing DNA in the peripheral blood of these patients, and this can also explain the presence of protein p53 in the leukocytes of these patients

  20. p53-dependent control of cell death by nicastrin: lack of requirement for presenilin-dependent gamma-secretase complex.

    Science.gov (United States)

    Pardossi-Piquard, Raphaëlle; Dunys, Julie; Giaime, Emilie; Guillot-Sestier, Marie-Victoire; St George-Hyslop, Peter; Checler, Frédéric; Alves da Costa, Cristine

    2009-04-01

    Nicastrin (NCT) is a component of the presenilin (PS)-dependent gamma-secretase complexes that liberate amyloid beta-peptides from the beta-Amyloid Precursor Protein. Several lines of evidence indicate that the members of these complexes could also contribute to the control of cell death. Here we show that over-expression of NCT increases the viability of human embryonic kidney (HEK293) cells and decreases staurosporine (STS)- and thapsigargin (TPS)-induced caspase-3 activation in various cell lines from human and neuronal origins by Akt-dependent pathway. NCT lowers p53 expression, transcriptional activity and promoter transactivation and reduces p53 phosphorylation. NCT-associated protection against STS-stimulated cell death was completely abolished by p53 deficiency. Conversely, the depletion of NCT drastically enhances STS-induced caspase-3 activation and p53 pathway and favored p53 nuclear translocation. We examined whether NCT protective function depends on PS-dependent gamma-secretase activity. First, a 29-amino acid deletion known to reduce NCT-dependent amyloid beta-peptide production did not affect NCT-associated protective phenotype. Second, NCT still reduces STS-induced caspase-3 activation in fibroblasts lacking PS1 and PS2. Third, the gamma-secretase inhibitor DFK167 did not affect NCT-mediated reduction of p53 activity. Altogether, our study indicates that NCT controls cell death via phosphoinositide 3-kinase/Akt and p53-dependent pathways and that this function remains independent of the activity and molecular integrity of the gamma-secretase complexes.

  1. Evodiamine selectively targets cancer stem-like cells through the p53-p21-Rb pathway

    International Nuclear Information System (INIS)

    Han, Seula; Woo, Jong Kyu; Jung, Yuchae; Jeong, Dawoon; Kang, Minsook; Yoo, Young-Ji; Lee, Hani; Oh, Seung Hyun; Ryu, Jae-Ha; Kim, Woo-Young

    2016-01-01

    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.

  2. 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.

  3. Suicide genes or p53 gene and p53 target genes as targets for cancer gene therapy by ionizing radiation

    International Nuclear Information System (INIS)

    Liu Bing; Chinese Academy of Sciences, Beijing; Zhang Hong

    2005-01-01

    Radiotherapy has some disadvantages due to the severe side-effect on the normal tissues at a curative dose of ionizing radiation (IR). Similarly, as a new developing approach, gene therapy also has some disadvantages, such as lack of specificity for tumors, limited expression of therapeutic gene, potential biological risk. To certain extent, above problems would be solved by the suicide genes or p53 gene and its target genes therapies targeted by ionizing radiation. This strategy not only makes up the disadvantage from radiotherapy or gene therapy alone, but also promotes success rate on the base of lower dose. By present, there have been several vectors measuring up to be reaching clinical trials. This review focused on the development of the cancer gene therapy through suicide genes or p53 and its target genes mediated by IR. (authors)

  4. Bioluminescence Detection of Cells Having Stabilized p53 in Response to a Genotoxic Event

    Directory of Open Access Journals (Sweden)

    Alnawaz Rehemtulla

    2004-01-01

    Full Text Available Inactivation of p53 is one of the most frequent molecular events in neoplastic transformation. Approximately 60% of all human tumors have mutations in both p53 alleles. Wild-type p53 activity is regulated in large part by the proteosome-dependent degradation of p53, resulting in a short p53 half-life in unstressed and untransformed cells. Activation of p53 by a variety of stimuli, including DNA damage induced by genotoxic drugs or radiation, is accomplished by stabilization of wild-type p53. The stabilized and active p53 can result in either cell-cycle arrest or apoptosis. Surprisingly, the majority of tumor-associated, inactivating p53 mutations also result in p53 accumulation. Thus, constitutive elevation of p53 levels in cells is a reliable measure of p53 inactivation, whereas transiently increased p53 levels reflect a recent genotoxic stress. In order to facilitate noninvasive imaging of p53 accumulation, we here describe the construction of a p53-luciferase fusion protein. Induction of DNA damage in cells expressing the fusion protein resulted in a time-dependent accumulation of the fusion that was noninvasively detected using bioluminescence imaging and validated by Western blot analysis. The p53-Luc protein retains p53 function because its expression in HCT116 cells lacking functional p53 resulted in activation of p21 expression as well as induction of apoptosis in response to a DNA damaging event. Employed in a transgenic animal model, the proposed p53-reporter fusion protein will be useful for studying p53 activation in response to exposure to DNA-damaging carcinogenic agents. It could also be used to study p53 stabilization as a result of inactivating p53 mutations. Such studies will further our understanding of p53's role as the “guardian of the genome” and its function in tumorigenesis.

  5. Activation of SNAT1/SLC38A1 in human breast cancer: correlation with p-Akt overexpression

    International Nuclear Information System (INIS)

    Wang, Kuo; Cao, Fang; Fang, Wenzheng; Hu, Yongwei; Chen, Ying; Ding, Houzhong; Yu, Guanzhen

    2013-01-01

    SNAT1 is a subtype of the amino acid transport system A that has been implicated to play a potential role in cancer development and progression, yet its role in breast cancer remains unclear. In present study, we detected SNAT1 expression in breast cancers and explored its underlying mechanism in promoting breast carcinogenesis. RT-PCR and Western blotting were performed to analyze the transcription and protein levels of SNAT1 in breast cancer cell lines and fresh tissues. Tissue microarray blocks containing breast cancer specimens obtained from 210 patients were constructed. Expression of SNAT1 in these specimens was analyzed using immunohistochemical studies. SNAT1 was down-regulated by SNAT1-shRNA in breast cancer cells and the functional significance was measured. SNAT1 was up-regulated in breast cancer cell lines and breast cancer tissues. Overexpression of SNAT1 was observed in 127 cases (60.5%). Expression of SNAT1 was significantly associated with tumor size, nodal metastasis, advanced disease stage, Ki-67, and ER status. Suppression of endogenous SNAT1 leads to cell growth inhibition, cell cycle arrest, and apoptosis of 4T1 cells and lowered the phosphorylation level of Akt. SNAT1 expression correlated significantly with p-Akt expression in human breast cancer samples. The cross-talk between Akt signaling and SNAT1 might play a critical role in the development and progression of breast cancer, providing an important molecular basis for novel diagnostic markers and new attractive targets in the treatment of breast cancer patients

  6. Paracrine Apoptotic Effect of p53 Mediated by Tumor Suppressor Par-4

    Directory of Open Access Journals (Sweden)

    Ravshan Burikhanov

    2014-01-01

    Full Text Available The guardian of the genome, p53, is often mutated in cancer and may contribute to therapeutic resistance. Given that p53 is intact and functional in normal tissues, we harnessed its potential to inhibit the growth of p53-deficient cancer cells. Specific activation of p53 in normal fibroblasts selectively induced apoptosis in p53-deficient cancer cells. This paracrine effect was mediated by p53-dependent secretion of the tumor suppressor Par-4. Accordingly, the activation of p53 in normal mice, but not p53−/− or Par-4−/− mice, caused systemic elevation of Par-4, which induced apoptosis of p53-deficient tumor cells. Mechanistically, p53 induced Par-4 secretion by suppressing the expression of its binding partner, UACA, which sequesters Par-4. Thus, normal cells can be empowered by p53 activation to induce Par-4 secretion for the inhibition of therapy-resistant tumors.

  7. Disruption of focal adhesion kinase and p53 interaction with small molecule compound R2 reactivated p53 and blocked tumor growth

    International Nuclear Information System (INIS)

    Golubovskaya, Vita M; Ho, Baotran; Zheng, Min; Magis, Andrew; Ostrov, David; Morrison, Carl; Cance, William G

    2013-01-01

    Focal Adhesion Kinase (FAK) is a 125 kDa non-receptor kinase that plays a major role in cancer cell survival and metastasis. We performed computer modeling of the p53 peptide containing the site of interaction with FAK, predicted the peptide structure and docked it into the three-dimensional structure of the N-terminal domain of FAK involved in the complex with p53. We screened small molecule compounds that targeted the site of the FAK-p53 interaction and identified compounds (called Roslins, or R compounds) docked in silico to this site. By different assays in isogenic HCT116p53 + / + and HCT116 p53 - / - cells we identified a small molecule compound called Roslin 2 (R2) that bound FAK, disrupted the binding of FAK and p53 and decreased cancer cell viability and clonogenicity in a p53-dependent manner. In addition, dual-luciferase assays demonstrated that the R2 compound increased p53 transcriptional activity that was inhibited by FAK using p21, Mdm-2, and Bax-promoter targets. R2 also caused increased expression of p53 targets: p21, Mdm-2 and Bax proteins. Furthermore, R2 significantly decreased tumor growth, disrupted the complex of FAK and p53, and up-regulated p21 in HCT116 p53 + / + but not in HCT116 p53 - / - xenografts in vivo. In addition, R2 sensitized HCT116p53 + / + cells to doxorubicin and 5-fluorouracil. Thus, disruption of the FAK and p53 interaction with a novel small molecule reactivated p53 in cancer cells in vitro and in vivo and can be effectively used for development of FAK-p53 targeted cancer therapy approaches

  8. Expression of p53 protein in Barrett’s adenocarcinoma and adenocarcinoma of the gastric cardia and antrum

    Directory of Open Access Journals (Sweden)

    Jovanović Ivan

    2005-01-01

    Full Text Available Background/Aim. Most studies of esophageal and gastric adenocarcinomas have shown a very high rate of p53 gene mutation and/or protein overexpression, but the influence of the tumor site upon the frequency of p53 protein expression has not been evaluated (gastroesophageal junction, Barret's esophagus, and antrum. The aim of our study was to analyze the correlation between the selected clinico-pthological parameters, and p53 protein overexpression in regards to the particular tumor location. Methods. The material comprised 66 surgical specimens; 10 were Barrett’s carcinomas, 25 adenocarcinomas of the gastric cardia (type II adenocarcinoma of the esophagogastric junction - EGJ, and 31 adenocarcinomas of the antrum. Immunostaining for p53 protein was performed on formalin-fixed, paraffin-embedded tissue sections, using the alkaline phosphatase - antialkaline phosphatase (APAAP method. The cases were considered positive for p53 if at least 5% of the tumor cells expressed this protein by immunostaining. Results. There was no significant difference observed between the studied groups in regards to age, sex, Lauren’s classification and tumor differentiation. There was, however, a significant difference observed in the depth of tumor invasion between Barrrett’s adenocarcinoma and adenocarcinoma of the cardia compared with the adenocarcinoma of the antrum. Namely, at the time of surgery, both Barrett’s adenocarcinomas and adenocarcinomas of the cardia, were significantly more advanced comparing with the adenocarcinomas of the antrum. Overexpression of p53 was found in 40% (4/10 of Barrett’s adenocarcinomas, 72% (18/25 of adenocarcinoma of the cardia and 65% (20/31 of adenocarcinoma of the antrum. No significant differences in p53 expression in relation to sex, type (Lauren of tumor, depth of invasion, lymph node involvement, or tumor differentiation were observed in any of the analyzed groups of tumors. Patients with more advanced Barrett

  9. High eIF4E Overexpression in Node Negative Breast Cancer as Predictor for Recurrence

    National Research Council Canada - National Science Library

    Li, Benjamin

    2002-01-01

    .... EIF4E overexpression has been found in human malignancies (Li, 1997; Nathan, 1997). Furthermore, there appears to be an association of eIF4E overexpression and clinical outcomes (Li, 1998; Nathan, 1997; Li, 2001...

  10. The Inherited p53 Mutation in the Brazilian Population.

    Science.gov (United States)

    Achatz, Maria Isabel; Zambetti, Gerard P

    2016-12-01

    A common criticism of studying rare diseases is the often-limited relevance of the findings to human health. Here, we review ∼15 years of research into an unusual germline TP53 mutation (p.R337H) that began with its detection in children with adrenocortical carcinoma (ACC), a remarkably rare childhood cancer that is associated with poor prognosis. We have come to learn that the p.R337H mutation exists at a very high frequency in Southern and Southeastern Brazil, occurring in one of 375 individuals within a total population of ∼100 million. Moreover, it has been determined that carriers of this founder mutation display variable tumor susceptibility, ranging from isolated cases of pediatric ACC to Li-Fraumeni or Li-Fraumeni-like (LFL) syndromes, thus representing a significant medical issue for this country. Studying the biochemical and molecular consequences of this mutation on p53 tumor-suppressor activity, as well as the putative additional genetic alterations that cooperate with this mutation, is advancing our understanding of how p53 functions in tumor suppression in general. These studies, which originated with a rare childhood tumor, are providing important information for guiding genetic counselors and physicians in treating their patients and are already providing clinical benefit. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  11. Biologic role of activated leukocyte cell adhesion molecule overexpression in breast cancer cell lines and clinical tumor tissue.

    Science.gov (United States)

    Hein, Sibyll; Müller, Volkmar; Köhler, Nadine; Wikman, Harriet; Krenkel, Sylke; Streichert, Thomas; Schweizer, Michaela; Riethdorf, Sabine; Assmann, Volker; Ihnen, Maike; Beck, Katrin; Issa, Rana; Jänicke, Fritz; Pantel, Klaus; Milde-Langosch, Karin

    2011-09-01

    The activated leukocyte cell adhesion molecule (ALCAM) is overexpressed in many mammary tumors, but controversial results about its role and prognostic impact in breast cancer have been reported. Therefore, we evaluated the biologic effects of ALCAM expression in two breast cancer cell lines and a larger cohort of mammary carcinomas. By stable transfections, MCF7 cells with ALCAM overexpression and MDA-MB231 cells with reduced ALCAM levels were generated and analyzed in functional assays and cDNA microarrays. In addition, an immunohistochemical study on 347 patients with breast cancer with long-term follow-up and analysis of disseminated tumor cells (DTCs) was performed. In both cell lines, high ALCAM expression was associated with reduced cell motility. In addition, ALCAM silencing in MDA-MB231 cells resulted in lower invasive potential, whereas high ALCAM expression was associated with increased apoptosis in both cell lines. Among genes which were differentially expressed in clones with altered ALCAM expression, there was an overlap of 15 genes between both cell lines, among them cathepsin D, keratin 7, gelsolin, and ets2 whose deregulation was validated by western blot analysis. In MDA-MB231 cells, we observed a correlation with VEGF expression which was validated by enzyme-linked immuno sorbent assay (ELISA). Our IHC results on primary breast carcinomas showed that ALCAM expression was associated with an estrogen receptor-positive phenotype. In addition, strong ALCAM immunostaining correlated with nodal involvement and the presence of tumor cells in bone marrow. By Kaplan-Meier analysis, strong ALCAM expression in ductal carcinomas correlated with shorter recurrence-free intervals (P=0.048) and overall survival (OAS, P=0.003). Our results indicate that the biologic role of ALCAM in breast cancer is complex, but overexpression might be relevant for outcome in ductal carcinomas.

  12. Gain-of-function mutant p53 but not p53 deletion promotes head and neck cancer progression in response to oncogenic K-ras

    Science.gov (United States)

    Acin, Sergio; Li, Zhongyou; Mejia, Olga; Roop, Dennis R; El-Naggar, Adel K; Caulin, Carlos

    2015-01-01

    Mutations in p53 occur in over 50% of the human head and neck squamous cell carcinomas (SCCHN). The majority of these mutations result in the expression of mutant forms of p53, rather than deletions in the p53 gene. Some p53 mutants are associated with poor prognosis in SCCHN patients. However, the molecular mechanisms that determine the poor outcome of cancers carrying p53 mutations are unknown. Here, we generated a mouse model for SCCHN and found that activation of the endogenous p53 gain-of-function mutation p53R172H, but not deletion of p53, cooperates with oncogenic K-ras during SCCHN initiation, accelerates oral tumour growth, and promotes progression to carcinoma. Mechanistically, expression profiling of the tumours that developed in these mice and studies using cell lines derived from these tumours determined that mutant p53 induces the expression of genes involved in mitosis, including cyclin B1 and cyclin A, and accelerates entry in mitosis. Additionally, we discovered that this oncogenic function of mutant p53 was dependent on K-ras because the expression of cyclin B1 and cyclin A decreased, and entry in mitosis was delayed, after suppressing K-ras expression in oral tumour cells that express p53R172H. The presence of double-strand breaks in the tumours suggests that oncogene-dependent DNA damage resulting from K-ras activation promotes the oncogenic function of mutant p53. Accordingly, DNA damage induced by doxorubicin also induced increased expression of cyclin B1 and cyclin A in cells that express p53R172H. These findings represent strong in vivo evidence for an oncogenic function of endogenous p53 gain-of-function mutations in SCCHN and provide a mechanistic explanation for the genetic interaction between oncogenic K-ras and mutant p53. PMID:21952947

  13. The Coordinated P53 and Estrogen Receptor Cis-Regulation at an FLT1 Promoter SNP Is Specific to Genotoxic Stress and Estrogenic Compound

    Science.gov (United States)

    Langen, Jan-Stephan; Schoenfelder, Gilbert; Resnick, Michael A.; Inga, Alberto

    2010-01-01

    Background Recently, we established that a C>T single nucleotide polymorphism (SNP) in the promoter of the VEGF receptor FLT1 gene generates a ½ site p53 response element (RE-T) that results in p53 responsiveness of the promoter. The transcriptional control required an estrogen receptor (ER) ½ site response element (ERE1) 225 nt upstream to the RE-T. Methodology/Principal Findings Here we report the identification of a second ER ½ site (ERE2) located 145 bp downstream of the RE-T and establish that both EREs can impact p53-mediated transactivation of FLT1-T in a manner that is cell type and ER level dependent. Gene reporter assays and ChIP experiments conducted in the breast cancer-derived MCF7 cells revealed that the ERE2 site was sufficient for p53-mediated ERα recruitment and transactivation of the FLT1-T promoter/reporter construct. Surprisingly, unlike the case for other p53 target promoters, p53-mediated transactivation of FLT1-T constructs or expression of the endogenous FLT1 gene, as well as binding of p53 and ER at the promoter constructs, was inducible by doxorubicin but not by 5-fluorouracil. Furthermore, ER activity at FLT1-T was differentially affected by ER ligands, compared to a control TFF1/pS2 ER target promoter. The p53-related transcription factors (TFs) p73 and p63 had no effect on FLT1 transactivation. Conclusions/Significance We establish a new dimension to the p53 master regulatory network where p53-mediated transcription from a ½ site RE can be determined by ER binding at one or more cis-acting EREs in manner that is dependent on level of ER protein, the type of ER ligand and the specific p53-inducing agent. PMID:20422012

  14. Phenotype specific analyses reveal distinct regulatory mechanism for chronically activated p53.

    Directory of Open Access Journals (Sweden)

    Kristina Kirschner

    2015-03-01

    Full Text Available The downstream functions of the DNA binding tumor suppressor p53 vary depending on the cellular context, and persistent p53 activation has recently been implicated in tumor suppression and senescence. However, genome-wide information about p53-target gene regulation has been derived mostly from acute genotoxic conditions. Using ChIP-seq and expression data, we have found distinct p53 binding profiles between acutely activated (through DNA damage and chronically activated (in senescent or pro-apoptotic conditions p53. Compared to the classical 'acute' p53 binding profile, 'chronic' p53 peaks were closely associated with CpG-islands. Furthermore, the chronic CpG-island binding of p53 conferred distinct expression patterns between senescent and pro-apoptotic conditions. Using the p53 targets seen in the chronic conditions together with external high-throughput datasets, we have built p53 networks that revealed extensive self-regulatory 'p53 hubs' where p53 and many p53 targets can physically interact with each other. Integrating these results with public clinical datasets identified the cancer-associated lipogenic enzyme, SCD, which we found to be directly repressed by p53 through the CpG-island promoter, providing a mechanistic link between p53 and the 'lipogenic phenotype', a hallmark of cancer. Our data reveal distinct phenotype associations of chronic p53 targets that underlie specific gene regulatory mechanisms.

  15. Regulation of Mdmx and its role in the p53 pathway

    NARCIS (Netherlands)

    Meulmeester, Erik

    2006-01-01

    The p53 protein is an important tumor suppressor that acts as a key regulator of the integrity of the genome. Two essential regulators of the p53 protein are Mdm2 and its homologue Mdmx. Like Mdm2, Mdmx represses p53-induced transcription. However, Mdmx cannot ubiquitinate or degrade p53 opposed to

  16. Mutant Mice Lacking the p53 C-Terminal Domain Model Telomere Syndromes

    NARCIS (Netherlands)

    Simeonova, I.; Jaber, S.; Draskovic, I.; Bardot, B.; Fang, M.; Bouarich-Bourimi, R.; Lejour, V.; Charbonnier, L.; Soudais, C.; Bourdon, J.C.; Huerre, M.; Londono-Vallejo, A.; Toledo, F.

    2013-01-01

    Mutations in p53, although frequent in human cancers, have not been implicated in telomere-related syndromes. Here, we show that homozygous mutant mice expressing p53(Delta31), a p53 lacking the C-terminal domain, exhibit increased p53 activity and suffer from aplastic anemia and pulmonary fibrosis,

  17. Identification of two novel functional p53 responsive elements in the herpes simplex virus-1 genome.

    Science.gov (United States)

    Hsieh, Jui-Cheng; Kuta, Ryan; Armour, Courtney R; Boehmer, Paul E

    2014-07-01

    Analysis of the herpes simplex virus-1 (HSV-1) genome reveals two candidate p53 responsive elements (p53RE), located in proximity to the replication origins oriL and oriS, referred to as p53RE-L and p53RE-S, respectively. The sequences of p53RE-L and p53RE-S conform to the p53 consensus site and are present in HSV-1 strains KOS, 17, and F. p53 binds to both elements in vitro and in virus-infected cells. Both p53RE-L and p53RE-S are capable of conferring p53-dependent transcriptional activation onto a heterologous reporter gene. Importantly, expression of the essential immediate early viral transactivator ICP4 and the essential DNA replication protein ICP8, that are adjacent to p53RE-S and p53RE-L, are repressed in a p53-dependent manner. Taken together, this study identifies two novel functional p53RE in the HSV-1 genome and suggests a complex mechanism of viral gene regulation by p53 which may determine progression of the lytic viral replication cycle or the establishment of latency. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. p53-dependent non-coding RNA networks in chronic lymphocytic leukemia

    NARCIS (Netherlands)

    Blume, C. J.; Hotz-Wagenblatt, A.; Hüllein, J.; Sellner, L.; Jethwa, A.; Stolz, T.; Slabicki, M.; Lee, K.; Sharathchandra, A.; Benner, A.; Dietrich, S.; Oakes, C. C.; Dreger, P.; te Raa, D.; Kater, A. P.; Jauch, A.; Merkel, O.; Oren, M.; Hielscher, T.; Zenz, T.

    2015-01-01

    Mutations of the tumor suppressor p53 lead to chemotherapy resistance and a dismal prognosis in chronic lymphocytic leukemia (CLL). Whereas p53 targets are used to identify patient subgroups with impaired p53 function, a comprehensive assessment of non-coding RNA targets of p53 in CLL is missing. We

  19. p53-Dependent Nestin Regulation Links Tumor Suppression to Cellular Plasticity in Liver Cancer

    DEFF Research Database (Denmark)

    Tschaharganeh, Darjus F; Xue, Wen; Calvisi, Diego F

    2014-01-01

    The p53 tumor suppressor coordinates a series of antiproliferative responses that restrict the expansion of malignant cells, and as a consequence, p53 is lost or mutated in the majority of human cancers. Here, we show that p53 restricts expression of the stem and progenitor-cell-associated protei...... by p53 restricts cellular plasticity and tumorigenesis in liver cancer....

  20. p53-dependent inhibition of TrxR1 contributes to the tumor-specific induction of apoptosis by RITA.

    Science.gov (United States)

    Hedström, Elisabeth; Eriksson, Sofi; Zawacka-Pankau, Joanna; Arnér, Elias S J; Selivanova, Galina

    2009-11-01

    Thioredoxin reductase 1 (TrxR1) is a key regulator in many redox-dependent cellular pathways, and is often overexpressed in cancer. Several studies have identified TrxR1 as a potentially important target for anticancer therapy. The low molecular weight compound RITA (NSC 652287) binds p53 and induces p53-dependent apoptosis. Here we found that RITA also targets TrxR1 by non-covalent binding, followed by inhibition of its activity in vitro and by inhibition of TrxR activity in cancer cells. Interestingly, a novel approximately 130 kDa form of TrxR1, presumably representing a stable covalently linked dimer, and an increased generation of reactive oxygen species (ROS) were induced by RITA in cancer cells in a p53-dependent manner. Similarly, the gold-based TrxR inhibitor auranofin induced apoptosis related to oxidative stress, but independently of p53 and without apparent induction of the approximately 130 kDa form of TrxR1. In contrast to the effects observed in cancer cells, RITA did not inhibit TrxR or ROS formation in normal fibroblasts (NHDF). The inhibition of TrxR1 can sensitize tumor cells to agents that induce oxidative stress and may directly trigger cell death. Thus, our results suggest that a unique p53-dependent effect of RITA on TrxR1 in cancer cells might synergize with p53-dependent induction of pro-apoptotic genes and oxidative stress, thereby leading to a robust induction of cancer cell death, without affecting non-transformed cells.

  1. Nardilysin controls intestinal tumorigenesis through HDAC1/p53-dependent transcriptional regulation.

    Science.gov (United States)

    Kanda, Keitaro; Sakamoto, Jiro; Matsumoto, Yoshihide; Ikuta, Kozo; Goto, Norihiro; Morita, Yusuke; Ohno, Mikiko; Nishi, Kiyoto; Eto, Koji; Kimura, Yuto; Nakanishi, Yuki; Ikegami, Kanako; Yoshikawa, Takaaki; Fukuda, Akihisa; Kawada, Kenji; Sakai, Yoshiharu; Ito, Akihiro; Yoshida, Minoru; Kimura, Takeshi; Chiba, Tsutomu; Nishi, Eiichiro; Seno, Hiroshi

    2018-04-19

    Colon cancer is a complex disease affected by a combination of genetic and epigenetic factors. Here we demonstrate that nardilysin (N-arginine dibasic convertase; NRDC), a metalloendopeptidase of the M16 family, regulates intestinal tumorigenesis via its nuclear functions. NRDC is highly expressed in human colorectal cancers. Deletion of the Nrdc gene in ApcMin mice crucially suppressed intestinal tumor development. In ApcMin mice, epithelial cell-specific deletion of Nrdc recapitulated the tumor suppression observed in Nrdc-null mice. Moreover, epithelial cell-specific overexpression of Nrdc significantly enhanced tumor formation in ApcMin mice. Notably, epithelial NRDC controlled cell apoptosis in a gene dosage-dependent manner. In human colon cancer cells, nuclear NRDC directly associated with HDAC1, and controlled both acetylation and stabilization of p53, with alterations of p53 target apoptotic factors. These findings demonstrate that NRDC is critically involved in intestinal tumorigenesis through its epigenetic regulatory function, and targeting NRDC may lead to a novel prevention or therapeutic strategy against colon cancer.

  2. Overexpression of miR-206 suppresses glycolysis, proliferation and migration in breast cancer cells via PFKFB3 targeting

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Xin; Lyu, Pengwei; Cao, Zhang; Li, Jingruo; Guo, Guangcheng; Xia, Wanjun; Gu, Yuanting, E-mail: zzyuantinggu@126.com

    2015-08-07

    miRNAs, sorting as non-coding RNAs, are differentially expressed in breast tumor and act as tumor promoters or suppressors. miR-206 could suppress the progression of breast cancer, the mechanism of which remains unclear. The study here was aimed to investigate the effect of miR-206 on human breast cancers. We found that miR-206 was down-regulated while one of its predicted targets, 6-Phosphofructo-2-kinase (PFKFB3) was up-regulated in human breast carcinomas. 17β-estradiol dose-dependently decreased miR-206 expression as well as enhanced PFKFB3 mRNA and protein expression in estrogen receptor α (ERα) positive breast cancer cells. Furthermore, we identified that miR-206 directly interacted with 3′-untranslated region (UTR) of PFKFB3 mRNA. miR-206 modulated PFKFB3 expression in MCF-7, T47D and SUM159 cells, which was influenced by 17β-estradiol depending on ERα expression. In addition, miR-206 overexpression impeded fructose-2,6-bisphosphate (F2,6BP) production, diminished lactate generation and reduced cell proliferation and migration in breast cancer cells. In conclusion, our study demonstrated that miR-206 regulated PFKFB3 expression in breast cancer cells, thereby stunting glycolysis, cell proliferation and migration. - Highlights: • miR-206 was down-regulated and PFKFB3 was up-regulated in human breast carcinomas. • 17β-estradiol regulated miR-206 and PFKFB3 expression in ERα+ cancer cells. • miR-206directly interacted with 3′-UTR of PFKFB3 mRNA. • miR-206 fructose-2,6-bisphosphate (F2,6BP) impeded production and lactate generation. • miR-206 reduced cell proliferation and migration in breast cancer cells.

  3. Combined Analysis of COX-2 and p53 Expressions Reveals Synergistic Inverse Correlations with Microsatellite Instability and CpG Island Methylator Phenotype in Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Shuji Ogino

    2006-06-01

    Full Text Available Cyclooxygenase-2 (COX-2 overexpression and mutations of p53 (a known COX-2 regulator are inversely associated with microsatellite instability—high (MSI-H and CpG island methylator phenotype (CIMP, characterized by extensive promoter methylation, is associated with MSI-H. However, no studies have comprehensively examined interrelations between COX-2, p53, MSI, and CIMP. Using MethyLight, we measured DNA methylation in five CIMP-specific gene promoters [CACNA1G, CDKN2A (p16/INK4A, CRABP1, MLH1, and NEUROG1] in relatively unbiased samples of 751 colorectal cancer cases obtained from two large prospective cohorts; 115 (15% tumors were CIMP-high (≥ 4 of 5 methylated promoters, 251 (33% were CIMP-low (1 to 3 methylated promoters, and the remaining 385 (51% were CIMP-0 (no methylated promoters. CIMP-high tumors were much less frequent in COX-2+/p53+ tumors (4.6% than in COX-2+/p53- tumors (19%; P < .0001, COX-2-/p53+ tumors (17%; P = .04, and COX-2-/p53- tumors (28%; P < .0001. In addition, COX-2+/p53+ tumors were significantly less common in MSI-H CIMP-high tumors (9.7% than in non-MSI-H CIMP-low/CIMP-0 tumors (44–47%; P < .0001. In conclusion, COX-2 and p53 alterations were synergistically inversely correlated with both MSI-H and CIMP-high. Our data suggest that a combined analysis of COX-2 and p53 may be more useful for the molecular classification of colorectal cancer than either COX-2 or p53 analysis alone.

  4. PHTS, a novel putative tumor suppressor, is involved in the transformation reversion of HeLaHF cells independently of the p53 pathway

    International Nuclear Information System (INIS)

    Yu Dehua; Fan, Wufang; Liu, Guohong; Nguy, Vivian; Chatterton, Jon E.; Long Shilong; Ke, Ning; Meyhack, Bernd; Bruengger, Adrian; Brachat, Arndt; Wong-Staal, Flossie; Li, Qi-Xiang

    2006-01-01

    HeLaHF is a non-transformed revertant of HeLa cells, likely resulting from the activation of a putative tumor suppressor(s). p53 protein was stabilized in this revertant and reactivated for certain transactivation functions. Although p53 stabilization has not conclusively been linked to the reversion, it is clear that the genes in p53 pathway are involved. The present study confirms the direct role of p53 in HeLaHF reversion by demonstrating that RNAi-mediated p53 silencing partially restores anchorage-independent growth potential of the revertant through the suppression of anoikis. In addition, we identified a novel gene, named PHTS, with putative tumor suppressor properties, and showed that this gene is also involved in HeLaHF reversion independently of the p53 pathway. Expression profiling revealed that PHTS is one of the genes that is up-regulated in HeLaHF but not in HeLa. It encodes a putative protein with CD59-like domains. RNAi-mediated PHTS silencing resulted in the partial restoration of transformation (anchorage-independent growth) in HeLaHF cells, similar to that of p53 gene silencing, implying its tumor suppressor effect. However, the observed increased transformation potential by PHTS silencing appears to be due to an increased anchorage-independent proliferation rate rather than suppression of anoikis, unlike the effect of p53 silencing. p53 silencing did not affect PHTS gene expression, and vice versa, suggesting PHTS may function in a new and p53-independent tumor suppressor pathway. Furthermore, over-expression of PHTS in different cancer cell lines, in addition to HeLa, reduces cell growth likely via induced apoptosis, confirming the broad PHTS tumor suppressor properties

  5. Cytosolic phospholipase A2 activation correlates with HER2 overexpression and mediates estrogen-dependent breast cancer cell growth.

    LENUS (Irish Health Repository)

    Caiazza, Francesco

    2010-05-01

    Cytosolic phospholipase A(2)alpha (cPLA(2)alpha) catalyzes the hydrolysis of membrane glycerol-phospholipids to release arachidonic acid as the first step of the eicosanoid signaling pathway. This pathway contributes to proliferation in breast cancer, and numerous studies have demonstrated a crucial role of cyclooxygenase 2 and prostaglandin E(2) release in breast cancer progression. The role of cPLA(2)alpha activation is less clear, and we recently showed that 17beta-estradiol (E2) can rapidly activate cPLA(2)alpha in MCF-7 breast cancer cells. Overexpression or gene amplification of HER2 is found in approximately 30% of breast cancer patients and correlates with a poor clinical outcome and resistance to endocrine therapy. This study reports the first evidence for a correlation between cPLA(2)alpha enzymatic activity and overexpression of the HER2 receptor. The activation of cPLA(2)alpha in response to E2 treatment was biphasic with the first phase dependent on trans-activation through the matrix metalloproteinase-dependent release of heparin-bound epidermal growth factor. EGFR\\/HER2 heterodimerization resulted in downstream signaling through the ERK1\\/2 cascade to promote cPLA(2)alpha phosphorylation at Ser505. There was a correlation between HER2 and cPLA(2)alpha expression in six breast cancer cell lines examined, and inhibition of HER2 activation or expression in the SKBR3 cell line using herceptin or HER2-specific small interfering RNA, respectively, resulted in decreased activation and expression of cPLA(2)alpha. Pharmacological blockade of cPLA(2)alpha using a specific antagonist suppressed the growth of both MCF-7 and SKBR3 cells by reducing E2-induced proliferation and by stimulating cellular apoptosis and necrosis. This study highlights cPLAalpha(2) as a potential target for therapeutic intervention in endocrine-dependent and endocrine-independent breast cancer.

  6. Docosahexaenoic Acid Modulates a HER2-Associated Lipogenic Phenotype, Induces Apoptosis, and Increases Trastuzumab Action in HER2-Overexpressing Breast Carcinoma Cells

    OpenAIRE

    Ravacci, Graziela Rosa; Brentani, Maria Mitzi; Tortelli, Tharcisio Citrângulo; Torrinhas, Raquel Suzana M. M.; Santos, Jéssica Reis; Logullo, Angela Flávia; Waitzberg, Dan Linetzky

    2015-01-01

    In breast cancer, lipid metabolic alterations have been recognized as potential oncogenic stimuli that may promote malignancy. To investigate whether the oncogenic nature of lipogenesis closely depends on the overexpression of HER2 protooncogene, the normal breast cell line, HB4a, was transfected with HER2 cDNA to obtain HER2-overexpressing HB4aC5.2 cells. Both cell lines were treated with trastuzumab and docosahexaenoic acid. HER2 overexpression was accompanied by an increase in the expressi...

  7. A nanobody modulates the p53 transcriptional program without perturbing its functional architecture

    Science.gov (United States)

    Bethuyne, Jonas; De Gieter, Steven; Zwaenepoel, Olivier; Garcia-Pino, Abel; Durinck, Kaat; Verhelle, Adriaan; Hassanzadeh-Ghassabeh, Gholamreza; Speleman, Frank; Loris, Remy; Gettemans, Jan

    2014-01-01

    The p53 transcription factor plays an important role in genome integrity. To perform this task, p53 regulates the transcription of genes promoting various cellular outcomes including cell cycle arrest, apoptosis or senescence. The precise regulation of this activity remains elusive as numerous mechanisms, e.g. posttranslational modifications of p53 and (non-)covalent p53 binding partners, influence the p53 transcriptional program. We developed a novel, non-invasive tool to manipulate endogenous p53. Nanobodies (Nb), raised against the DNA-binding domain of p53, allow us to distinctively target both wild type and mutant p53 with great specificity. Nb3 preferentially binds ‘structural’ mutant p53, i.e. R175H and R282W, while a second but distinct nanobody, Nb139, binds both mutant and wild type p53. The co-crystal structure of the p53 DNA-binding domain in complex with Nb139 (1.9 Å resolution) reveals that Nb139 binds opposite the DNA-binding surface. Furthermore, we demonstrate that Nb139 does not disturb the functional architecture of the p53 DNA-binding domain using conformation-specific p53 antibody immunoprecipitations, glutaraldehyde crosslinking assays and chromatin immunoprecipitation. Functionally, the binding of Nb139 to p53 allows us to perturb the transactivation of p53 target genes. We propose that reduced recruitment of transcriptional co-activators or modulation of selected post-transcriptional modifications account for these observations. PMID:25324313

  8. Sublethal dose of irradiation enhances invasion of malignant glioma cells through p53-MMP 2 pathway in U87MG mouse brain tumor model

    International Nuclear Information System (INIS)

    Pei, Jian; Park, In-Ho; Ryu, Hyang-Hwa; Li, Song-Yuan; Li, Chun-Hao; Lim, Sa-Hoe; Wen, Min; Jang, Woo-Youl; Jung, Shin

    2015-01-01

    Glioblastoma is a highly lethal neoplasm that frequently recurs locally after radiotherapy, and most of these recurrences originate from near the irradiated target field. In the present study, we identified the effects of radiation on glioma invasion and p53, TIMP-2, and MMP-2 expression through in vitro and in vivo experiments. The U87MG (wt p53) and U251 (mt p53) human malignant glioma cell lines were prepared, and the U2OS (wt 53) and Saos2 (del p53) osteosarcoma cell lines were used as p53 positive and negative controls. The four cell lines and p53 knock-downed U87MG cells received radiation (2–6 Gy) and were analyzed for expression of p53 and TIMP-2 by Western blot, and MMP-2 activity was detected by zymography. In addition, the effects of irradiation on directional invasion of malignant glioma were evaluated by implanting nude mice with bioluminescent u87-Fluc in vivo followed by MMP-2, p53, and TIMP-2 immunohisto-chemistry and in situ zymography. MMP-2 activity and p53 expression increased in proportional to the radiation dose in cell lines with wt p53, but not in the cell lines with del or mt p53. TIMP-2 expression did not increase in U87MG cells. MMP-2 activity decreased in p53 knock-downed U87MG cells but increased in the control group. Furthermore, radiation enhanced MMP-2 activity and increased tumor margin invasiveness in vivo. Tumor cells invaded by radiation overexpressed MMP-2 and p53 and revealed high gelatinolytic activity compared with those of non-radiated tumor cells. Radiation-induced upregulation of p53 modulated MMP-2 activity, and the imbalance between MMP-2 and TIMP-2 may have an important role in glioblastoma invasion by degrading the extracellular matrix. Bioluminescent “U87-Fluc”was useful for observing tumor formation without sacrifice after implanting tumor cells in the mouse brain. These findings suggest that the radiotherapy involved field for malignant glioma needs to be reconsidered, and that future trials should investigate

  9. Natural products induce a G protein-mediated calcium pathway activating p53 in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ginkel, Paul R. van; Yan, Michael B. [UW Carbone Cancer Center, University of Wisconsin, Madison, WI 53792 (United States); Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53792 (United States); Bhattacharya, Saswati [UW Carbone Cancer Center, University of Wisconsin, Madison, WI 53792 (United States); Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53792 (United States); Department of Pediatrics, University of Wisconsin, Madison, WI 53792 (United States); Polans, Arthur S., E-mail: aspolans@wisc.edu [UW Carbone Cancer Center, University of Wisconsin, Madison, WI 53792 (United States); Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53792 (United States); Kenealey, Jason D. [UW Carbone Cancer Center, University of Wisconsin, Madison, WI 53792 (United States); Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53792 (United States); Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602 (United States)

    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. - Highlights: • Natural products having low toxicity increase cytoplasmic calcium in cancer cells. • A G-protein/IP{sub 3} pathway mediates the release of calcium from the ER. • The elevation of intracellular calcium modulates p53 activity. • p53 and other Ca{sup 2+}-dependent pro-apoptotic pathways inhibit cancer cell growth.

  10. Natural products induce a G protein-mediated calcium pathway activating p53 in cancer cells

    International Nuclear Information System (INIS)

    Ginkel, Paul R. van; 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. - Highlights: • Natural products having low toxicity increase cytoplasmic calcium in cancer cells. • A G-protein/IP 3 pathway mediates the release of calcium from the ER. • The elevation of intracellular calcium modulates p53 activity. • p53 and other Ca 2+ -dependent pro-apoptotic pathways inhibit cancer cell growth.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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.

  12. 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.

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

    International Nuclear Information System (INIS)

    Morris, Suzanne M.; Akerman, Gregory S.; Desai, Varsha G.; Tsai, Chen-an; Tolleson, William H.; Melchior, William B.; Lin, Chien-Ju; Fuscoe, James C.; Casciano, Daniel A.; Chen, James J.

    2008-01-01

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

  14. Overexpression of ETV4 protein in triple-negative breast cancer is associated with a higher risk of distant metastasis

    Directory of Open Access Journals (Sweden)

    Yuan ZY

    2014-09-01

    Full Text Available Zhong-Yu Yuan,1–3,* Ting Dai,1,2,* Shu-Sen Wang,1–3 Rou-Jun Peng,1–3 Xing-Hua Li,1,2 Tao Qin,1–3 Li-Bing Song,1,2 Xi Wang1,2,41State Key Laboratory of Oncology in South China, Guangzhou, People's Republic of China; 2Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China; 3Department of Medical Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, People's Republic of China; 4Department of Breast Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, People's Republic of China  *These authors contributed equally to this work Background: Patients with triple-negative breast cancer (TNBC present a higher probability of distant metastasis and lack of effective targeted therapy. ETS translocation variant 4 (ETV4 is an ETS (E-26 transcription factor and has been associated with tumor metastasis. However, the clinical and functional significance of ETV4 in TNBC still remains unclear. Methods: A human tumor metastasis polymerase chain reaction array was used to profile differential expression of tumor metastasis-related genes in TNBC tissue. Real-time reverse transcription and Western blot analyses were performed to verify ETV4 expression in TNBC cells and tissue. Immunohistochemistry was used to detect expression of ETV4 protein in 135 TNBC tissue samples for association between ETV4 protein expression and clinical outcomes. Results: A total total of eight upregulated (CCL7, KISS1, MET, MMP7, NR4A3, ETV4, TIMP3, and TSHR and three downregulated (ITGA7, SSTR, and MMP2 genes were identified between TNBC tissue and the luminal subtype of breast cancer tissue. ETV4 messenger ribonucleic acid was more than five-fold upregulated in TNBC tissue compared with the control tissue. ETV4 overexpression was found in 57.0% of 135 TNBC cases. Overexpression of ETV4 protein was associated with an advanced stage and a higher proportion of positive lymph node and lymphovascular invasion. Patients with an ETV4

  15. Regulatory module involving FGF13, miR-504, and p53 regulates ribosomal biogenesis and supports cancer cell survival

    Science.gov (United States)

    Bublik, Débora R.; Bursać, Slađana; Sheffer, Michal; Oršolić, Ines; Shalit, Tali; Tarcic, Ohad; Kotler, Eran; Mouhadeb, Odelia; Hoffman, Yonit; Fuchs, Gilad; Levin, Yishai; Volarević, Siniša; Oren, Moshe

    2017-01-01

    The microRNA miR-504 targets TP53 mRNA encoding the p53 tumor suppressor. miR-504 resides within the fibroblast growth factor 13 (FGF13) gene, which is overexpressed in various cancers. We report that the FGF13 locus, comprising FGF13 and miR-504, is transcriptionally repressed by p53, defining an additional negative feedback loop in the p53 network. Furthermore, we show that FGF13 1A is a nucleolar protein that represses ribosomal RNA transcription and attenuates protein synthesis. Importantly, in cancer cells expressing high levels of FGF13, the depletion of FGF13 elicits increased proteostasis stress, associated with the accumulation of reactive oxygen species and apoptosis. Notably, stepwise neoplastic transformation is accompanied by a gradual increase in FGF13 expression and increased dependence on FGF13 for survival (“nononcogene addiction”). Moreover, FGF13 overexpression enables cells to cope more effectively with the stress elicited by oncogenic Ras protein. We propose that, in cells in which activated oncogenes drive excessive protein synthesis, FGF13 may favor survival by maintaining translation rates at a level compatible with the protein quality-control capacity of the cell. Thus, FGF13 may serve as an enabler, allowing cancer cells to evade proteostasis stress triggered by oncogene activation. PMID:27994142

  16. Sirtuin 7 promotes cellular survival following genomic stress by attenuation of DNA damage, SAPK activation and p53 response

    Energy Technology Data Exchange (ETDEWEB)

    Kiran, Shashi; Oddi, Vineesha [Laboratory of Cancer Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, 500001 (India); Ramakrishna, Gayatri, E-mail: gayatrirama1@gmail.com [Laboratory of Cancer Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, 500001 (India); Laboratory of Cancer Cell Biology, Department of Research, Institute of Liver and Biliary Sciences, Delhi 110070 (India)

    2015-02-01

    Maintaining the genomic integrity is a constant challenge in proliferating cells. Amongst various proteins involved in this process, Sirtuins play a key role in DNA damage repair mechanisms in yeast as well as mammals. In the present work we report the role of one of the least explored Sirtuin viz., SIRT7, under conditions of genomic stress when treated with doxorubicin. Knockdown of SIRT7 sensitized osteosarcoma (U2OS) cells to DNA damage induced cell death by doxorubicin. SIRT7 overexpression in NIH3T3 delayed cell cycle progression by causing delay in G1 to S transition. SIRT7 overexpressing cells when treated with low dose of doxorubicin (0.25 µM) showed delayed onset of senescence, lesser accumulation of DNA damage marker γH2AX and lowered levels of growth arrest markers viz., p53 and p21 when compared to doxorubicin treated control GFP expressing cells. Resistance to DNA damage following SIRT7 overexpression was also evident by EdU incorporation studies where cellular growth arrest was significantly delayed. When treated with higher dose of doxorubicin (>1 µM), SIRT7 conferred resistance to apoptosis by attenuating stress activated kinases (SAPK viz., p38 and JNK) and p53 response thereby shifting the cellular fate towards senescence. Interestingly, relocalization of SIRT7 from nucleolus to nucleoplasm together with its co-localization with SAPK was an important feature associated with DNA damage. SIRT7 mediated resistance to doxorubicin induced apoptosis and senescence was lost when p53 level was restored by nutlin treatment. Overall, we propose SIRT7 attenuates DNA damage, SAPK activation and p53 response thereby promoting cellular survival under conditions of genomic stress. - Highlights: • Knockdown of SIRT7 sensitized cells to DNA damage induced apoptosis. • SIRT7 delayed onset of premature senescence by attenuating DNA damage response. • Overexpression of SIRT7 delayed cell cycle progression by delaying G1/S transition. • Upon DNA damage SIRT

  17. In vivo examination of {sup 188}Re(I)-tricarbonyl-labeled trastuzumab to target HER2-overexpressing breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K.-T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, T.-W. [Institute of Nuclear Energy Research, Longtan 32546, Taiwan (China); Lo, Jem-Mau [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jmlo@mx.nthu.edu.tw

    2009-05-15

    Introduction: Trastuzumab (Herceptin), a humanized IgG1 monoclonal antibody directed against the extracellular domain of the HER2 protein, acts as an immunotherapeutic agent for HER2-overexpressing human breast cancers. Radiolabeled trastuzumab with {beta}- or {alpha} emitters can be used as radioimmunotherapeutic agent for the similar purpose but with additional radiation effect. Methods: In this study, trastuzumab was labeled with {sup 188}Re for radioimmunotherapy of HER2/neu-positive breast cancer. {sup 188}Re(I)-tricarbonyl ion, [{sup 188}Re(OH{sub 2}){sub 3}(CO){sub 3}]{sup +}, was employed as a precursor for directly labeling the monoclonal antibody with {sup 188}Re. The immunoreactivity of {sup 188}Re(I)-trastuzumab was estimated by competition receptor-binding assay using HER2/neu-overexpressive BT-474 human breast cancer cells. The localization properties of {sup 188}Re(I)-trastuzumab within both tumor and normal tissues of athymic mice bearing BT-474 human breast cancer xenografts (HER2/neu-overexpressive) and similar mice bearing MCF-7 human breast cancer xenografts (HER2/neu-low expressive) were investigated. Results: When incubated with human serum albumin and histidine at 25{sup o}C, {sup 188}Re(I)-trastuzumab was found to be stable within 24 h. The IC{sub 50} of {sup 188}Re(I)-trastuzumab was found to be 22.63{+-}4.57 nM. {sup 188}Re(I)-trastuzumab was shown to accumulate specifically in BT-474 tumor tissue in in vivo biodistribution studies. By microSPECT/CT, the image of {sup 188}Re localized BT-474 tumor was clearly visualized within 24 h. In contrast, {sup 188}Re(I)-trastuzumab uptake in HER2-low-expressing MCF-7 tumor was minimal, and the {sup 188}Re image at the localization of the tumor was dim. Conclusion: These results reveal that {sup 188}Re(I)-trastuzumab could be an appropriate radioimmunotherapeutic agent for the treatment of HER2/neu-overexpressing cancers.

  18. FGF1 protects neuroblastoma SH-SY5Y cells from p53-dependent apoptosis through an intracrine pathway regulated by FGF1 phosphorylation

    Science.gov (United States)

    Pirou, Caroline; Montazer-Torbati, Fatemeh; Jah, Nadège; Delmas, Elisabeth; Lasbleiz, Christelle; Mignotte, Bernard; Renaud, Flore

    2017-01-01

    Neuroblastoma, a sympathetic nervous system tumor, accounts for 15% of cancer deaths in children. In contrast to most human tumors, p53 is rarely mutated in human primary neuroblastoma, suggesting impaired p53 activation in neuroblastoma. Various studies have shown correlations between fgf1 expression levels and both prognosis severity and tumor chemoresistance. As we previously showed that fibroblast growth factor 1 (FGF1) inhibited p53-dependent apoptosis in neuron-like PC12 cells, we initiated the study of the interaction between the FGF1 and p53 pathways in neuroblastoma. We focused on the activity of either extracellular FGF1 by adding recombinant rFGF1 in media, or of intracellular FGF1 by overexpression in human SH-SY5Y and mouse N2a neuroblastoma cell lines. In both cell lines, the genotoxic drug etoposide induced a classical mitochondrial p53-dependent apoptosis. FGF1 was able to inhibit p53-dependent apoptosis upstream of mitochondrial events in SH-SY5Y cells by both extracellular and intracellular pathways. Both rFGF1 addition and etoposide treatment increased fgf1 expression in SH-SY5Y cells. Conversely, rFGF1 or overexpressed FGF1 had no effect on p53-dependent apoptosis and fgf1 expression in neuroblastoma N2a cells. Using different FGF1 mutants (that is, FGF1K132E, FGF1S130A and FGF1S130D), we further showed that the C-terminal domain and phosphorylation of FGF1 regulate its intracrine anti-apoptotic activity in neuroblastoma SH-SY5Y cells. This study provides the first evidence for a role of an intracrine growth factor pathway on p53-dependent apoptosis in neuroblastoma, and could lead to the identification of key regulators involved in neuroblastoma tumor progression and chemoresistance. PMID:29048426

  19. A dual role of p53 in the control of autophagy.

    Science.gov (United States)

    Tasdemir, Ezgi; Chiara Maiuri, M; Morselli, Eugenia; Criollo, Alfredo; D'Amelio, Marcello; Djavaheri-Mergny, Mojgan; Cecconi, Francesco; Tavernarakis, Nektarios; Kroemer, Guido

    2008-08-01

    Genotoxic stress can induce autophagy in a p53-dependent fashion and p53 can transactivate autophagy-inducing genes. We have observed recently that inactivation of p53 by deletion, depletion or inhibition can trigger autophagy. Thus, human and mouse cells subjected to knockout, knockdown or pharmacological inhibition of p53 manifest signs of autophagy such as depletion of p62/SQSTM1, LC3 lipidation, redistribution of GFP-LC3 in cytoplasmic puncta, and accumulation of autophagosomes and autolysosomes, both in vitro and in vivo. Inhibition of p53 causes autophagy in enucleated cells, indicating that the cytoplasmic, non-nuclear pool of p53 can regulate autophagy. Accordingly, retransfection of p53(-/-) cells with wild-type p53 as well as a p53 mutant that is excluded from the nucleus (due to the deletion of the nuclear localization sequence) can inhibit autophagy, whereas retransfection with a nucleus-restricted p53 mutant (in which the nuclear localization sequence has been deleted) does not inhibit autophagy. Several distinct autophagy inducers (e.g., starvation, rapamycin, lithium, tunicamycin and thapsigargin) stimulate the rapid degradation of p53. In these conditions, inhibition of the p53-specific E3 ubiquitin ligase HDM2 can avoid p53 depletion and simultaneously prevent the activation of autophagy. Moreover, a p53 mutant that lacks the HDM2 ubiquitinylation site and hence is more stable than wild-type p53 is particularly efficient in suppressing autophagy. In conclusion, p53 plays a dual role in the control of autophagy. On the one hand, nuclear p53 can induce autophagy through transcriptional effects. On the other hand, cytoplasmic p53 may act as a master repressor of autophagy.

  20. Poly(ADP-ribose polymerase 1 (PARP1 overexpression in human breast cancer stem cells and resistance to olaparib.

    Directory of Open Access Journals (Sweden)

    Marine Gilabert

    Full Text Available BACKGROUND: Breast cancer stem cells (BCSCs have been recognized as playing a major role in various aspects of breast cancer biology. To identify specific biomarkers of BCSCs, we have performed comparative proteomics of BCSC-enriched and mature cancer cell populations from the human breast cancer cell line (BCL, BrCA-MZ-01. METHODS: ALDEFLUOR assay was used to sort BCSC-enriched (ALDH+ and mature cancer (ALDH- cell populations. Total proteins were extracted from both fractions and subjected to 2-Dimensional Difference In-Gel Electrophoresis (2-D DIGE. Differentially-expressed spots were excised and proteins were gel-extracted, digested and identified using MALDI-TOF MS. RESULTS: 2-D DIGE identified poly(ADP-ribose polymerase 1 (PARP1 as overexpressed in ALDH+ cells from BrCA-MZ-01. This observation was confirmed by western blot and extended to four additional human BCLs. ALDH+ cells from BRCA1-mutated HCC1937, which had the highest level of PARP1 overexpression, displayed resistance to olaparib, a specific PARP1 inhibitor. CONCLUSION: An unbiased proteomic approach identified PARP1 as upregulated in ALDH+, BCSC-enriched cells from various human BCLs, which may contribute to clinical resistance to PARP inhibitors.

  1. Conformational detection of p53's oligomeric state by FlAsH Fluorescence

    OpenAIRE

    Webber, Tawnya M.; Allen, Andrew C.; Ma, Wai Kit; Molloy, Rhett G.; Kettelkamp, Charisse N.; Dow, Caitlin A.; Gage, Matthew J.

    2009-01-01

    The p53 tumor suppressor protein is a critical checkpoint in prevention of tumor formation, and the function of p53 is dependent on proper formation of the active tetramer. In vitro studies have shown that p53 binds DNA most efficiently as a tetramer, though inactive p53 is predicted to be monomeric in vivo. We demonstrate that FlAsH binding can be used to distinguish between oligomeric states of p53, providing a potential tool to explore p53 oligomerization in vivo. The FlAsH tetra-cysteine ...

  2. Aggregation-primed molten globule conformers of the p53 core domain provide potential tools for studying p53C aggregation in cancer.

    Science.gov (United States)

    Pedrote, Murilo M; de Oliveira, Guilherme A P; Felix, Adriani L; Mota, Michelle F; Marques, Mayra de A; Soares, Iaci N; Iqbal, Anwar; Norberto, Douglas R; Gomes, Andre M O; Gratton, Enrico; Cino, Elio A; Silva, Jerson L

    2018-05-31

    The functionality of the tumor suppressor p53 is altered in more than 50% of human cancers, and many individuals with cancer exhibit amyloid-like buildups of aggregated p53. An understanding of what triggers the pathogenic amyloid conversion of p53 is required for the further development of cancer therapies. Here, perturbation of the p53 core domain (p53C) with sub-denaturing concentrations of guanidine hydrochloride and high hydrostatic pressure revealed native-like molten globule (MG) states, a subset of which were highly prone to amyloidogenic aggregation. We found that MG conformers of p53C, likely representing population-weighted averages of multiple states, have different volumetric properties, as determined by pressure perturbation and size-exclusion chromatography. We also found that they bind the fluorescent dye 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) and have a native-like tertiary structure that occludes the single Trp residue in p53. Fluorescence experiments revealed conformational changes of the single Trp and Tyr residues before p53 unfolding and the presence of MG conformers, some of which were highly prone to aggregation. P53C exhibited marginal unfolding cooperativity, which could be modulated from unfolding to aggregation pathways with chemical or physical forces. We conclude that trapping amyloid precursor states in solution is a promising approach for understanding p53 aggregation in cancer. Our findings support the use of single-Trp fluorescence as a probe for evaluating p53 stability, effects of mutations, and the efficacy of therapeutics designed to stabilize p53. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Effect of recombinant adenovirus encoding human p53 tumor suppressor gene (rAd-p53) on the growth and radiotherapeutic sensitivity of human lymphoma cell lines

    International Nuclear Information System (INIS)

    Yu Zeyang; Fan Wo; Li Dongqing; Zhu Ran; Wang Yongqing; Wu Jinchang

    2008-01-01

    Objective: To explore the inhibitory effect and radiation sensitization of recombinant adenovirus encoding human p53 tumor suppressor gene (rAd-p53) on human lymphoma cell lines. Methods: Human lymphoma cell lines Raji and Daudi were treated with rAd-p53, radiation therapy and combined treatment, respectively. The cell growth inhibition was assessed by MTT. The p53 protein expression was detected by Western blotting, and p53 mRNA was detected by BT-PCB. Results: The MTT results showed that the inhibitory effect and radiosensitivity enhancement of rAd-p53 on human lymphoma cell lines were not obvious [Raji: (27.5±4.1)%; Daudi: (28.1±1.6)%]. The results of Western blotting and BT-PCB showed that extrinsic p53 protein and p53 mRNA were expressed to some degree, but not at high-level. In addition, the results didn't demonstrate obvious radiosensitivity enhancement. Conclusions: The role of inhibition and radiosensitivity enhancement of rAd-p53 was not significant on human lymphoma cell lines. (authors)

  4. Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2.

    Science.gov (United States)

    Slamon, D J; Leyland-Jones, B; Shak, S; Fuchs, H; Paton, V; Bajamonde, A; Fleming, T; Eiermann, W; Wolter, J; Pegram, M; Baselga, J; Norton, L

    2001-03-15

    The HER2 gene, which encodes the growth factor receptor HER2, is amplified and HER2 is overexpressed in 25 to 30 percent of breast cancers, increasing the aggressiveness of the tumor. We evaluated the efficacy and safety of trastuzumab, a recombinant monoclonal antibody against HER2, in women with metastatic breast cancer that overexpressed HER2. We randomly assigned 234 patients to receive standard chemotherapy alone and 235 patients to receive standard chemotherapy plus trastuzumab. Patients who had not previously received adjuvant (postoperative) therapy with an anthracycline were treated with doxorubicin (or epirubicin in the case of 36 women) and cyclophosphamide alone (138 women) or with trastuzumab (143 women). Patients who had previously received adjuvant anthracycline were treated with paclitaxel alone (96 women) or paclitaxel with trastuzumab (92 women). The addition of trastuzumab to chemotherapy was associated with a longer time to disease progression (median, 7.4 vs. 4.6 months; P<0.001), a higher rate of objective response (50 percent vs. 32 percent, P<0.001), a longer duration of response (median, 9.1 vs. 6.1 months; P<0.001), a lower rate of death at 1 year (22 percent vs. 33 percent, P=0.008), longer survival (median survival, 25.1 vs. 20.3 months; P=0.01), and a 20 percent reduction in the risk of death. The most important adverse event was cardiac dysfunction of New York Heart Association class III or IV, which occurred in 27 percent of the group given an anthracycline, cyclophosphamide, and trastuzumab; 8 percent of the group given an anthracycline and cyclophosphamide alone; 13 percent of the group given paclitaxel and trastuzumab; and 1 percent of the group given paclitaxel alone. Although the cardiotoxicity was potentially severe and, in some cases, life-threatening, the symptoms generally improved with standard medical management. Trastuzumab increases the clinical benefit of first-line chemotherapy in metastatic breast cancer that

  5. Impact of the p53 status of tumor cells on extrinsic and intrinsic apoptosis signaling.

    Science.gov (United States)

    Wachter, Franziska; Grunert, Michaela; Blaj, Cristina; Weinstock, David M; Jeremias, Irmela; Ehrhardt, Harald

    2013-04-17

    The p53 protein is the best studied target in human cancer. For decades, p53 has been believed to act mainly as a tumor suppressor and by transcriptional regulation. Only recently, the complex and diverse function of p53 has attracted more attention. Using several molecular approaches, we studied the impact of different p53 variants on extrinsic and intrinsic apoptosis signaling. We reproduced the previously published results within intrinsic apoptosis induction: while wild-type p53 promoted cell death, different p53 mutations reduced apoptosis sensitivity. The prediction of the impact of the p53 status on the extrinsic cell death induction was much more complex. The presence of p53 in tumor cell lines and primary xenograft tumor cells resulted in either augmented, unchanged or reduced cell death. The substitution of wild-type p53 by mutant p53 did not affect the extrinsic apoptosis inducing capacity. In summary, we have identified a non-expected impact of p53 on extrinsic cell death induction. We suggest that the impact of the p53 status of tumor cells on extrinsic apoptosis signaling should be studied in detail especially in the context of therapeutic approaches that aim to restore p53 function to facilitate cell death via the extrinsic apoptosis pathway.

  6. Transcriptional Inhibition of the Human Papilloma Virus Reactivates Tumor Suppressor p53 in Cervical Carcinoma Cells

    Science.gov (United States)

    Kochetkov, D. V.; Ilyinskaya, G. V.; Komarov, P. G.; Strom, E.; Agapova, L. S.; Ivanov, A. V.; Budanov, A. V.; Frolova, E. I.; Chumakov, P. M.

    2009-01-01

    Inactivation of tumor suppressor p53 accompanies the majority of human malignancies. Restoration of p53 function causes death of tumor cells and is potentially suitable for gene therapy of cancer. In cervical carcinoma, human papilloma virus (HPV) E6 facilitates proteasomal degradation of p53. Hence, a possible approach to p53 reactivation is the use of small molecules suppressing the function of viral proteins. HeLa cervical carcinoma cells (HPV-18) with a reporter construct containing the b-galactosidase gene under the control of a p53-responsive promoter were used as a test system to screen a library of small molecules for restoration of the transcriptional activity of p53. The effect of the two most active compounds was studied with cell lines differing in the state of p53-dependent signaling pathways. The compounds each specifically activated p53 in cells expressing HPV-18 and, to a lesser extent, HPV-16 and exerted no effect on control p53-negative cells or cells with the intact p53-dependent pathways. Activation of p53 in cervical carcinoma cells was accompanied by induction of p53-dependent CDKN1 (p21), inhibition of cell proliferation, and induction of apoptosis. In addition, the two compounds dramatically decreased transcription of the HPV genome, which was assumed to cause p53 reactivation. The compounds were low-toxic for normal cells and can be considered as prototypes of new anticancer drugs. PMID:17685229

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-10

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

  8. An adaptive molecular timer in p53-meidated cell fate decision

    Science.gov (United States)

    Zhang, Xiao-Peng; Wang, Ping; Liu, Feng; Wang, Wei

    The tumor suppressor p53 decides cellular outcomes in the DNA damage response. It is intriguing to explore the link between p53 dynamics and cell fates. We developed a theoretical model of p53 signaling network to clarify the mechanism of cell fate decision mediated by its dynamics. We found that the interplay between p53-Mdm2 negative feedback loop and p53-PTEN-Mdm2 positive feedback loop shapes p53 dynamics. Depending on the intensity of DNA damage, p53 shows three modes of dynamics: persistent pulses, two-phase dynamics with pulses followed by sustained high levels and straightforward high levels. Especially, p53 shows two-phase dynamics upon moderated damage and the required number of p53 pulses before apoptosis induction decreases with increasing DNA damage. Our results suggested there exists an adaptive molecular timer that determines whether and when the apoptosis switch should be triggered. We clarified the mechanism behind the switching of p53 dynamical modes by bifurcation analysis. Moreover, we reproduced the experimental results that drug additions alter p53 pulses to sustained p53 activation and leads to senescence. Our work may advance the understanding the significance of p53 dynamics in tumor suppression. This work was supported by National Natural Science Foundation of China (Nos. 11175084, 11204126 and 31361163003).

  9. The critical role of catalase in prooxidant and antioxidant function of p53

    Science.gov (United States)

    Kang, M Y; Kim, H-B; Piao, C; Lee, K H; Hyun, J W; Chang, I-Y; You, H J

    2013-01-01

    The tumor suppressor p53 is an important regulator of intracellular reactive oxygen species (ROS) levels, although downstream mediators of p53 remain to be elucidated. Here, we show that p53 and its downstream targets, p53-inducible ribonucleotide reductase (p53R2) and p53-inducible gene 3 (PIG3), physically and functionally interact with catalase for efficient regulation of intracellular ROS, depending on stress intensity. Under physiological conditions, the antioxidant functions of p53 are mediated by p53R2, which maintains increased catalase activity and thereby protects against endogenous ROS. After genotoxic stress, high levels of p53 and PIG3 cooperate to inhibit catalase activity, leading to a shift in the oxidant/antioxidant balance toward an oxidative status, which could augment apoptotic cell death. These results highlight the essential role of catalase in p53-mediated ROS regulation and suggest that the p53/p53R2–catalase and p53/PIG3–catalase pathways are critically involved in intracellular ROS regulation under physiological conditions and during the response to DNA damage, respectively. PMID:22918438

  10. Characterization of fibroblast growth factor receptor 2 overexpression in the human breast cancer cell line SUM-52PE

    International Nuclear Information System (INIS)

    Tannheimer, Stacey L; Rehemtulla, Alnawaz; Ethier, Stephen P

    2000-01-01

    The fibroblast growth factor receptor (FGFR)2 gene has been shown to be amplified in 5-10% of breast cancer patients. A breast cancer cell line developed in our laboratory, SUM-52PE, was shown to have a 12-fold amplification of the FGFR2 gene, and FGFR2 message was found to be overexpressed 40-fold in SUM-52PE cells as compared with normal human mammary epithelial (HME) cells. Both human breast cancer (HBC) cell lines and HME cells expressed two FGFR2 isoforms, whereas SUM-52PE cells overexpressed those two isoforms, as well as several unique FGFR2 polypeptides. SUM-52PE cells expressed exclusively FGFR2-IIIb isoforms, which are high-affinity receptors for fibroblast growth factor (FGF)-1 and FGF-7. Differences were identified in the expression of the extracellular Ig-like domains, acid box and carboxyl termini, and several variants not previously reported were isolated from these cells. The FGFR family of receptor tyrosine kinases includes four members, all of which are highly alternatively spliced and glycosylated. For FGFR2, alternative splicing of the second half of the third Ig-like domain, involving exons IIIb and IIIc, is a mutually exclusive choice that affects ligand binding specificity and affinity [1,2,3]. It appears that the second half of the third Ig-like domain can dictate high affinity for FGF-2 or keratinocyte growth factor (KGF), whereas affinity for FGF-1 appears to remain the same [3]. Alternative splicing of the carboxyl terminus has been shown to involve at least two different exons that can produce at least three different variants. The C1-type and C2-type carboxyl termini are encoded by the same exon, and have two different splice acceptor sites, whereas the C3-type carboxyl terminus is encoded by a separate exon [4]. The biologic significance of the C1 carboxyl terminus, as compared with the shorter C3 variant found primarily in tumorigenic samples, has been studied in NIH3T3 transfection assays, in which C3 variants were able to produce

  11. Role of p53 in Mammary Epithelial Cell Senescence

    Science.gov (United States)

    2009-05-01

    putative progenitor/stem cell is also indicated. Terminal ductal-lobular unit Duct Collecting Ducts Nipple Fatty tissue Stromal fibroblasts Progenitor...Framingham Heart Study (Murabito et al. 2007). The study involved 1,335 participants, including 58 women with breast cancer and 59 men with prostate

  12. Mitochondrial localization of the low level p53 protein in proliferative cells

    Energy Technology Data Exchange (ETDEWEB)

    Ferecatu, Ioana; Bergeaud, Marie; Rodriguez-Enfedaque, Aida; Le Floch, Nathalie [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Oliver, Lisa [INSERM U601, Universite de Nantes, Faculte de Medecine, Nantes Cedex (France); Rincheval, Vincent; Renaud, Flore [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Vallette, Francois M. [INSERM U601, Universite de Nantes, Faculte de Medecine, Nantes Cedex (France); Mignotte, Bernard [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France); Vayssiere, Jean-Luc, E-mail: jean-luc.vayssiere@uvsq.fr [Laboratoire de Genetique et Biologie Cellulaire - CNRS UMR 8159, Universite de Versailles Saint-Quentin-en-Yvelines, Versailles, France and Laboratoire de Genetique Moleculaire et Physiologique, Ecole Pratique des Hautes Etudes, Versailles (France)

    2009-10-02

    p53 protein plays a central role in suppressing tumorigenesis by inducing cell cycle arrest or apoptosis through transcription-dependent and -independent mechanisms. Emerging publications suggest that following stress, a fraction of p53 translocates to mitochondria to induce cytochrome c release and apoptosis. However, the localization of p53 under unstressed conditions remains largely unexplored. Here we show that p53 is localized at mitochondria in absence of apoptotic stimuli, when cells are proliferating, localization observed in various cell types (rodent and human). This is also supported by acellular assays in which p53 bind strongly to mitochondria isolated from rat liver. Furthermore, the mitochondria subfractionation study and the alkaline treatment of the mitochondrial p53 revealed that the majority of mitochondrial p53 is present in the membranous compartments. Finally, we identified VDAC, a protein of the mitochondrial outer-membrane, as a putative partner of p53 in unstressed/proliferative cells.

  13. Mitochondrial localization of the low level p53 protein in proliferative cells

    International Nuclear Information System (INIS)

    Ferecatu, Ioana; Bergeaud, Marie; Rodriguez-Enfedaque, Aida; Le Floch, Nathalie; Oliver, Lisa; Rincheval, Vincent; Renaud, Flore; Vallette, Francois M.; Mignotte, Bernard; Vayssiere, Jean-Luc

    2009-01-01

    p53 protein plays a central role in suppressing tumorigenesis by inducing cell cycle arrest or apoptosis through transcription-dependent and -independent mechanisms. Emerging publications suggest that following stress, a fraction of p53 translocates to mitochondria to induce cytochrome c release and apoptosis. However, the localization of p53 under unstressed conditions remains largely unexplored. Here we show that p53 is localized at mitochondria in absence of apoptotic stimuli, when cells are proliferating, localization observed in various cell types (rodent and human). This is also supported by acellular assays in which p53 bind strongly to mitochondria isolated from rat liver. Furthermore, the mitochondria subfractionation study and the alkaline treatment of the mitochondrial p53 revealed that the majority of mitochondrial p53 is present in the membranous compartments. Finally, we identified VDAC, a protein of the mitochondrial outer-membrane, as a putative partner of p53 in unstressed/proliferative cells.

  14. The dependence receptor Ret induces apoptosis in somatotrophs through a Pit-1/p53 pathway, preventing tumor growth.

    Science.gov (United States)

    Cañibano, Carmen; Rodriguez, Noela L; Saez, Carmen; Tovar, Sulay; Garcia-Lavandeira, Montse; Borrello, Maria Grazia; Vidal, Anxo; Costantini, Frank; Japon, Miguel; Dieguez, Carlos; Alvarez, Clara V

    2007-04-18

    Somatotrophs are the only pituitary cells that express Ret, GFRalpha1 and GDNF. This study investigated the effects of Ret in a somatotroph cell line, in primary pituitary cultures and in Ret KO mice. Ret regulates somatotroph numbers by inducing Pit-1 overexpression, leading to increased p53 expression and apoptosis, both of which can be prevented with Ret or Pit-1 siRNA. The Pit-1 overexpression is mediated by sustained activation of PKCdelta, JNK, c/EBPalpha and CREB induced by a complex of Ret, caspase 3 and PKCdelta. In the presence of GDNF, Akt is activated, and the Pit-1 overexpression and resulting apoptosis are blocked. The adenopituitary of Ret KO mice is larger than normal, showing Pit-1 and somatotroph hyperplasia. In normal animals, activation of the Ret/Pit-1/p53 pathway by retroviral introduction of Ret blocked tumor growth in vivo. Thus, somatotrophs have an intrinsic mechanism for controlling Pit-1/GH production through an apoptotic/survival pathway. Ret might be of value for treatment of pituitary adenomas.

  15. Interplay between PTB and miR-1285 at the p53 3′UTR modulates the levels of p53 and its isoform Δ40p53α

    Science.gov (United States)

    Katoch, Aanchal; George, Biju; Iyyappan, Amrutha; Khan, Debjit

    2017-01-01

    Abstract p53 and its translational isoform Δ40p53 are involved in many important cellular functions like cell cycle, cell proliferation, differentiation and metabolism. Expression of both the isoforms can be regulated at different steps. In this study, we explored the role of 3′UTR in regulating the expression of these two translational isoforms. We report that the trans acting factor, Polypyrimidine Tract Binding protein (PTB), also interacts specifically with 3′UTR of p53 mRNA and positively regulates expression of p53 isoforms. Our results suggest that there is interplay between miRNAs and PTB at the 3′UTR under normal and stress conditions like DNA damage. Interestingly, PTB showed some overlapping binding regions in the p53 3′UTR with miR-1285. In fact, knockdown of miR-1285 as well as expression of p53 3′UTR with mutated miR-1285 binding sites resulted in enhanced association of PTB with the 3′UTR, which provides mechanistic insights of this interplay. Taken together, the results provide a plausible molecular basis of how the interplay between miRNAs and the PTB protein at the 3′UTR can play pivotal role in fine tuning the expression of the two p53 isoforms. PMID:28973454

  16. Prognostic value of p53 in patients with muscle-invasive bladder cancer treated with preoperative radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Catherine S; Pollack, Alan; Czerniak, Bogdan A; Chyle, Valerian; Zagars, Gunar K; Dinney, Colin P; Benedict, William F

    1995-07-01

    Purpose/Objective: The overexpression of mutated and/or wild type p53 has been associated with poorer prognosis in patients with bladder cancer. However, most studies have involved a mixed patient population, including those with superficial and muscle-invasive disease, and some patients treated with adjuvant chemotherapy. In this study we examine the prognostic significance of p53 detected immunohistochemically in a cohort of patients with muscle-invasive transitional cell carcinoma of the bladder treated relatively uniformly with preoperative radiotherapy 4-6 weeks prior to radical cystectomy. Materials and Methods: Of 301 patients treated with preoperative radiotherapy (50 Gy in 25 fractions over 5 weeks) for muscle-invasive bladder cancer between 1960-1983, adequate material for immunohistochemical analysis of p53 was obtained in 107. Formalin-fixed paraffin-embedded archival tissue was stained using monoclonal anti-p53 antibody D01 (Oncogene Science, Manhasset, NY). The immunostaining of p53 was considered positive if greater than 20% of the tumor nuclei were stained. There were 82 men and 25 women with a mean age of 61 yr and no patient received neoadjuvant or adjuvant chemotherapy. All patients were without distant metastasis prior to treatment initiation. The median follow-up for those living (n=32) was 88 mo. The number of patients by clinical stage was 48 for T2, 30 for T3a, and 29 for T3b. Results: Overall, 46% of the patients were p53 positive, with 42% in Stage T2, 57% in Stage T3a, and 41% in Stage T3b. The distributions of potential patient prognostic factors by p53 positivity were investigated and the only association was with lymphatic-vascular invasion (p=0.04, chi-square). No correlation was seen between p53 staining and pathologic complete response (seen in 47%), clinical-to-pathologic downstaging (seen in 69%), clinical stage, tumor grade, tumor morphology, tumor number, tumor size, gender, patient age, pretreatment hemoglobin levels, BUN

  17. XIAP over-expression is an independent poor prognostic marker in Middle Eastern breast cancer and can be targeted to induce efficient apoptosis.

    Science.gov (United States)

    Hussain, Azhar R; Siraj, Abdul Khalid; Ahmed, Maqbool; Bu, Rong; Pratheeshkumar, Poyil; Alrashed, Alanood M; Qadri, Zeeshan; Ajarim, Dahish; Al-Dayel, Fouad; Beg, Shaham; Al-Kuraya, Khawla S

    2017-09-11

    Breast cancer is the most common cancer in females and is ranked second in cancer-related deaths all over the world in women. Despite improvement in diagnosis, the survival rate of this disease has still not improved. X-linked Inhibitor of Apoptosis (XIAP) has been shown to be over-expressed in various cancers leading to poor overall survival. However, the role of XIAP in breast cancer from Middle Eastern region has not been fully explored. We examined the expression of XIAP in more than 1000 Middle Eastern breast cancer cases by immunohistochemistry. Apoptosis was measured by flow cytometry. Protein expression was determined by western blotting. Finally, in vivo studies were performed on nude mice following xenografting and treatment with inhibitors. XIAP was found to be over-expressed in 29.5% of cases and directly associated with clinical parameters such as tumor size, extra nodal extension, triple negative breast cancer and poorly differentiated breast cancer subtype. In addition, XIAP over-expression was also significantly associated with PI3-kinase pathway protein; p-AKT, proliferative marker; Ki-67 and anti-apoptotic marker; PARP. XIAP over-expression in our cohort of breast cancer was an independent poor prognostic marker in multivariate analysis. Next, we investigated inhibition of XIAP using a specific inhibitor; embelin and found that embelin treatment led to inhibition of cell viability and induction of apoptosis in breast cancer cells. Finally, breast cancer cells treated with combination of embelin and PI3-kinase inhibitor; LY294002 synergistically induced apoptosis and caused tumor growth regression in vivo. These data suggest that XIAP may be playing an important role in the pathogenesis of breast cancer and can be therapeutically targeted either alone or in combination with PI3-kinase inhibition to induce efficient apoptosis in breast cancer cells.

  18. Role of Tumor Suppressor P53 in Megakaryopoiesis and Platelet Function

    Science.gov (United States)

    Apostolidis, Pani A.; Woulfe, Donna S.; Chavez, Massiel; Miller, William M.; Papoutsakis, Eleftherios T.

    2011-01-01

    The pathobiological role of p53 has been widely studied, however its role in normophysiology is relatively unexplored. We previously showed that p53 knock-down increased ploidy in megakaryocytic cultures. This study aims to examine the effect of p53 loss on in vivo megakaryopoiesis, platelet production and function, and to investigate the basis for greater ploidy in p53−/− megakaryocytic cultures. Here, we used flow cytometry to analyze ploidy, DNA synthesis and apoptosis in murine cultured and bone marrow megakaryocytes following thrombopoietin administration and to analyze fibrinogen binding to platelets in vitro. Culture of p53−/− marrow cells for 6 days with thrombopoietin gave rise to 1.7-fold more megakaryocytes, 26.1±3.6% of which reached ploidy classes ≥64N compared to 8.2±0.9% of p53+/+ megakaryocytes. This was due to 30% greater DNA synthesis in p53−/− megakaryocytes and 31% greater apoptosis in p53+/+ megakaryocytes by day 4 of culture. Although the bone marrow and spleen steady-state megakaryocytic content and ploidy were similar in p53+/+ and p53−/− mice, thrombopoietin administration resulted in increased megakaryocytic polyploidization in p53−/− mice. Although their platelet counts were normal, p53−/− mice exhibited significantly longer bleeding times and p53−/− platelets were less sensitive than p53+/+ platelets to agonist-induced fibrinogen binding and P-selectin secretion. In summary, our in vivo and ex-vivo studies indicate that p53 loss leads to increased polyploidization during megakaryopoiesis. Our findings also suggest for the first time a direct link between p53 loss and the development of fully functional platelets resulting in hemostatic deficiencies. PMID:22024107

  19. Neem oil limonoids induces p53-independent apoptosis and autophagy.

    Science.gov (United States)

    Srivastava, Pragya; Yadav, Neelu; Lella, Ravi; Schneider, Andrea; Jones, Anthony; Marlowe, Timothy; Lovett, Gabrielle; O'Loughlin, Kieran; Minderman, Hans; Gogada, Raghu; Chandra, Dhyan

    2012-11-01

    Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells.

  20. Neem oil limonoids induces p53-independent apoptosis and autophagy

    Science.gov (United States)

    Chandra, Dhyan

    2012-01-01

    Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells. PMID:22915764

  1. Avoiding restorative proctocolectomy for colorectal cancer in patients with ulcerative colitis based on preoperative diagnosis involving p53 immunostaining: report of a case.

    Science.gov (United States)

    Sada, Haruki; Shimomura, Manabu; Hinoi, Takao; Egi, Hiroyuki; Kawaguchi, Koji; Yano, Takuya; Niitsu, Hiroaki; Saitou, Yasufumi; Sawada, Hiroyuki; Miguchi, Masashi; Adachi, Tomohiro; Ohdan, Hideki

    2015-03-26

    The standard operation for colitic cancer in ulcerative colitis (UC) is restorative proctocolectomy; however, sporadic colorectal cancer (CRC) can coincidentally arise in patients with UC and the optimal procedure remains controversial. Therefore, it is crucial to preoperatively determine whether the CRC in UC is a sporadic or colitic cancer. We report a case of avoiding proctocolectomy for sporadic CRC in a patient with UC based on preoperative diagnosis involving p53 immunostaining. A 73-year-old man with CRC in UC had undergone sigmoid colectomy with lymphadenectomy because of the submucosal deep invasion pathologically after endoscopic mucosal resection. The cancer was diagnosed sporadic cancer preoperatively not only based on the endoscopic, clinical, and histological patterns but also that the colon epithelium was unlikely to develop dysplasia as the circumference and unaffected UC mucosa did not detect p53 protein overexpression. Recent reports have shown that the immunohistochemical detection of p53 protein overexpression can be useful for a differential diagnosis and as a predictor of dysplasia and colitic cancer. The analysis of p53 mutation status based on immunostaining of p53 protein expression in the unaffected UC mucosa can be useful for the decision regarding a surgical procedure for CRC in patients with UC.

  2. Ectopic AP4 expression induces cellular senescence via activation of p53 in long-term confluent retinal pigment epithelial cells.

    Science.gov (United States)

    Wang, Yiping; Wong, Matthew Man-Kin; Zhang, Xiaojian; Chiu, Sung-Kay

    2015-11-15

    When cells are grown to confluence, cell-cell contact inhibition occurs and drives the cells to enter reversible quiescence rather than senescence. Confluent retinal pigment epithelial (RPE) cells exhibiting contact inhibition was used as a model in this study to examine the role of overexpression of transcription factor AP4, a highly expressed transcription factor in many types of cancer, in these cells during long-term culture. We generated stable inducible RPE cell clones expressing AP4 or AP4 without the DNA binding domain (DN-AP4) and observed that, when cultured for 24 days, RPE cells with a high level of AP4 exhibit a large, flattened morphology and even cease proliferating; these changes were not observed in DN-AP4-expressing cells or non-induced cells. In addition, AP4-expressing cells exhibited senescence-associated β-galactosidase activity and the senescence-associated secretory phenotype. We demonstrated that the induced cellular senescence was mediated by enhanced p53 expression and that AP4 regulates the p53 gene by binding directly to two of the three E-boxes present on the promoter of the p53 gene. Moreover, we showed that serum is essential for AP4 in inducing p53-associated cellular senescence. Collectively, we showed that overexpression of AP4 mediates cellular senescence involving in activation of p53 in long-term post-confluent RPE cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Prostate-Derived Ets Transcription Factor Overexpression is Associated with Nodal Metastasis, Hormone Receptor Positivity in Invasive Breast Cancer

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