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1

Docosahexaenoic acid induces the degradation of HPV E6/E7 oncoproteins by activating the ubiquitin-proteasome system.  

PubMed

The oncogenic human papillomavirus (HPV) E6/E7 proteins are essential for the onset and maintenance of HPV-associated malignancies. Here, we report that activation of the cellular ubiquitin-proteasome system (UPS) by the omega-3 fatty acid, docosahexaenoic acid (DHA), leads to proteasome-mediated degradation of E6/E7 viral proteins and the induction of apoptosis in HPV-infected cancer cells. The increases in UPS activity and degradation of E6/E7 oncoproteins were associated with DHA-induced overproduction of mitochondrial reactive oxygen species (ROS). Exogenous oxidative stress and pharmacological induction of mitochondrial ROS showed effects similar to those of DHA, and inhibition of ROS production abolished UPS activation, E6/E7 viral protein destabilization, and apoptosis. These findings identify a novel role for DHA in the regulation of UPS and viral proteins, and provide evidence for the use of DHA as a mechanistically unique anticancer agent for the chemoprevention and treatment of HPV-associated tumors. PMID:25393480

Jing, K; Shin, S; Jeong, S; Kim, S; Song, K-S; Park, J-H; Heo, J-Y; Seo, K-S; Park, S-K; Kweon, G-R; Wu, T; Park, J-I; Lim, K

2014-01-01

2

Docosahexaenoic acid induces the degradation of HPV E6/E7 oncoproteins by activating the ubiquitin–proteasome system  

PubMed Central

The oncogenic human papillomavirus (HPV) E6/E7 proteins are essential for the onset and maintenance of HPV-associated malignancies. Here, we report that activation of the cellular ubiquitin–proteasome system (UPS) by the omega-3 fatty acid, docosahexaenoic acid (DHA), leads to proteasome-mediated degradation of E6/E7 viral proteins and the induction of apoptosis in HPV-infected cancer cells. The increases in UPS activity and degradation of E6/E7 oncoproteins were associated with DHA-induced overproduction of mitochondrial reactive oxygen species (ROS). Exogenous oxidative stress and pharmacological induction of mitochondrial ROS showed effects similar to those of DHA, and inhibition of ROS production abolished UPS activation, E6/E7 viral protein destabilization, and apoptosis. These findings identify a novel role for DHA in the regulation of UPS and viral proteins, and provide evidence for the use of DHA as a mechanistically unique anticancer agent for the chemoprevention and treatment of HPV-associated tumors. PMID:25393480

Jing, K; Shin, S; Jeong, S; Kim, S; Song, K-S; Park, J-H; Heo, J-Y; Seo, K-S; Park, S-K; Kweon, G-R; Wu, T; Park, J-I; Lim, K

2014-01-01

3

The Human Papillomavirus E7 Oncoprotein  

PubMed Central

The human papillomavirus (HPV) E7 oncoprotein shares functional similarities with such proteins as adenovirus E1A and SV40 large tumor antigen. As one of only two viral proteins always expressed in HPV-associated cancers, E7 plays a central role in both the viral life cycle and carcinogenic transformation. In the HPV viral life cycle, E7 disrupts the intimate association between cellular differentiation and proliferation in normal epithelium, allowing for viral replication in cells that would no longer be in the dividing population. This function is directly reflected in the transforming activities of E7, including tumor initiation and induction of genomic instability. PMID:19007963

McLaughlin-Drubin, Margaret E.; Münger, Karl

2009-01-01

4

The human papillomavirus E7 oncoprotein  

SciTech Connect

The human papillomavirus (HPV) E7 oncoprotein shares functional similarities with such proteins as adenovirus E1A and SV40 large tumor antigen. As one of only two viral proteins always expressed in HPV-associated cancers, E7 plays a central role in both the viral life cycle and carcinogenic transformation. In the HPV viral life cycle, E7 disrupts the intimate association between cellular differentiation and proliferation in normal epithelium, allowing for viral replication in cells that would no longer be in the dividing population. This function is directly reflected in the transforming activities of E7, including tumor initiation and induction of genomic instability.

McLaughlin-Drubin, Margaret E. [Infectious Diseases Division, Channing Laboratory 861, 181 Longwood Avenue, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115 (United States)], E-mail: mdrubin@rics.bwh.harvard.edu; Muenger, Karl [Infectious Diseases Division, Channing Laboratory 861, 181 Longwood Avenue, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115 (United States)], E-mail: kmunger@rics.bwh.harvard.edu

2009-02-20

5

Enhanced tumour growth after DNA vaccination against human papilloma virus E7 oncoprotein: evidence for tumour-induced immune deviation  

Microsoft Academic Search

We have examined the induction of anti-tumour immunity in a murine model using a gene vaccine approach to deliver a well defined tumour antigen. The vaccines expressed the human papilloma virus type 16 (HPV 16) E7 oncoprotein, and protection was measured against HPV 16-expressing C3R tumour cell line in vivo. In control mice injected with saline, C3R cells initially formed

Minal T. Kotecha; Razi K. Afghan; Eleni Vasilikopoulou; Erica Wilson; Philip Marsh; W. Martin Kast; D. Huw Davies; Wilson Caparros-Wanderley

2003-01-01

6

Curcumin suppresses human papillomavirus oncoproteins, restores p53, Rb, and PTPN13 proteins and inhibits benzo[a]pyrene-induced upregulation of HPV E7.  

PubMed

Curcumin has great potential as a chemopreventive and chemotherapeutic agent; however, its effects on human papillomavirus (HPV)-associated molecular events are inadequately explored. This study examined the effects of curcumin on HPV-associated pathways involved in developing cervical cancer. We demonstrate for the first time that curcumin treatment suppresses cervical cancer cell growth in a three-dimensional raft culture system. Curcumin also inhibits tumorigenic characteristics as shown by decreases in both clonogenic potential and cell motility. Additionally, our findings show that curcumin treatment inhibits the transcription of HPV16 E6/E7 as early as 6?h posttreatment and restores the expression of tumor suppressor proteins p53, retinoblastoma protein, and PTPN13. While smoking is a recognized risk factor for cervical cancer, the molecular effects of smoke carcinogens on the expression of HPV E6/E7 oncogenes are not well known. We show for the first time that exposure to benzo[a]pyrene (BaP), a tobacco carcinogen, increases the expression of HPV E7 oncoprotein suggesting a molecular link between smoking and cervical cancer. Importantly, curcumin decreases the BaP induced increase in the expression of HPV E7 oncoprotein. The results of this study clearly demonstrate that curcumin alters HPV-associated molecular pathways in cervical cancer cells. These novel findings imply that curcumin may be an effective chemopreventive and therapeutic agent for cervical cancer prevention and treatment. PMID:21061268

Maher, Diane M; Bell, Maria C; O'Donnell, Emmylu A; Gupta, Brij K; Jaggi, Meena; Chauhan, Subhash C

2011-01-01

7

E6 and E7 oncoproteins from human papillomavirus type 16 induce activation of human transforming growth factor beta1 promoter throughout Sp1 recognition sequence.  

PubMed

Human Papillomavirus (HPV) infection is the main etiologic agent of cervical cancer and HPV E6 and E7 oncogenes trans-regulate many cellular genes. An association between TGF-beta1 gene expression and cervical cancer development has been suggested; however, the mechanisms by which HPV influences TGF-beta1 expression remain unclear. In the present study we analyzed the mechanism through which HPV-16 E6 and E7 oncoproteins regulate the TGF-beta1 promoter in cervical tumor cells. Our results showed that E6 and E7 increased TGF-beta1 promoter activity. Furthermore, we identified a specific DNA sequence motif in the TGF-beta1 core promoter that is responsible for trans-activation and that corresponds to the Sp1e-binding site associated with HPV-16 E6 and E7 oncoproteins. Mutational analysis showed that the Sp1e recognition site abolished the trans-activation caused by E6 and E7. These results suggest a physical interaction and functional cooperation between viral oncoproteins and cellular regulatory elements of the TGF-beta1 promoter, and may explain the contribution of HPV-16 to TGF-beta1 gene expression in cervical cancer. PMID:16987065

Peralta-Zaragoza, Oscar; Bermúdez-Morales, Víctor; Gutiérrez-Xicotencatl, Lourdes; Alcocer-González, Juan; Recillas-Targa, Félix; Madrid-Marina, Vicente

2006-01-01

8

Cancerous inhibitor of protein phosphatase 2A contributes to human papillomavirus oncoprotein E7-induced cell proliferation via E2F1.  

PubMed

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified oncoprotein that is overexpressed in many human malignant tumors including cervical cancer. Human papillomavirus (HPV) oncoprotein E7 is the key transformation factor in cervical cancer. Our previous data showed a positive association of CIP2A and HPV-16E7 protein levels; however, how CIP2A is regulated by HPV-E7 and the roles of CIP2A in HPV-E7-mediated cell proliferation are unknown. In this study, we demonstrated that HPV-16E7 protein significantly upregulating CIP2A mRNA and protein expression depended on retinoblastoma protein pRb rather than p130. CIP2A siRNA knockdown in HPV-E7-expressing cells inhibited cell proliferation, DNA synthesis and G1/S cell cycle progression. CIP2A siRNA decreased the protein levels of cyclin-dependent kinase 1 (Cdk1), Cdk2 and their partner cyclin A2, with no change in levels of Cdk4, Cdk6 and their partner cyclin D1. The downregulation of Cdk1 and Cdk2 was independent of c-Myc; instead, E2F1 was the main target of CIP2A in this process, as overexpression of E2F1 rescued the inhibitory effects of CIP2A siRNA knockdown on cell proliferation and G1 arrest of HPV-E7-expressing cells. Our studies reveal a novel function of CIP2A in HPV-16E7-mediated cell proliferation. PMID:25650660

Zhang, Weifang; Chen, Hanxiang; Chen, Yan; Liu, Juan; Wang, Xiao; Yu, Xiuping; Chen, Jason J; Zhao, Weiming

2015-03-10

9

Gene expression profile regulated by the HPV16 E7 oncoprotein and estradiol in cervical tissue  

PubMed Central

The HPV16 E7 oncoprotein and 17?-estradiol are important factors for the induction of premalignant lesions and cervical cancer. The study of these factors is crucial for a better understanding of cervical tumorigenesis. Here, we assessed the global gene expression profiles induced by the HPV16 E7 oncoprotein and/or 17?-estradiol in cervical tissue of FvB and K14E7 transgenic mice. We found that the most dramatic changes in gene expression occurred in K14E7 and FvB groups treated with 17?-estradiol. A large number of differentially expressed genes involved in the immune response were observed in 17?-estradiol treated groups. The E7 oncoprotein mainly affected the expression of genes involved in cellular metabolism. Our microarray data also identified differentially expressed genes that have not previously been reported in cervical cancer. The identification of genes regulated by E7 and 17?-estradiol, provides the basis for further studies on their role in cervical carcinogenesis. PMID:24210110

Cortés-Malagón, Enoc M.; Bonilla-Delgado, José; Díaz-Chávez, José; Hidalgo-Miranda, Alfredo; Romero-Cordoba, Sandra; Üren, Aykut; Çelik, Haydar; McCormick, Matthew; Munguía-Moreno, José A.; Ibarra-Sierra, Eloisa; Escobar-Herrera, Jaime; Lambert, Paul F.; Mendoza-Villanueva, Daniel; Bermudez-Cruz, Rosa M.; Gariglio, Patricio

2014-01-01

10

Differential Regulation of the Pocket Domains of the Retinoblastoma Family Proteins by the HPVI6 E7 Oncoprotein1  

Microsoft Academic Search

The human papillomavirus E7 oncoprotein binds to the retinoblastoma (Rb) tumor suppressor protein, and the binding to Rb correlates with the oncogenic potential of E7. Recent studies from several laboratories indicated that the half-life of the Rb protein is reduced in cells that are stably transformed with E7, suggesting that E7 could induce the proteolytic degradation of Rb. To investigate

Ekaterena Berezutskaya; Bo Yu; Alexei Morozov; Pradip Raychaudhuri; Srilata Bagchi

1997-01-01

11

The EMBO Journal Vol.18 No.9 pp.24492458, 1999 The E7 oncoprotein associates with Mi2 and histone  

E-print Network

of the human papilloma virus E7 protein. This provides the first indication that viral oncoproteins control virus E7 oncoprotein/Mi2/transformation Introduction Many human papilloma viruses (HPVs) infect.A.Miska contributed equally to this work E7 is the main transforming protein of human papil- loma virus type 16 (HPV16

Miska, Eric

12

Requirement of E7 oncoprotein for viability of HeLa cells  

Microsoft Academic Search

Most human papillomavirus (HPV)-positive cervical cancers contain integrated copies of the viral genome in their chromosomes and express the viral oncoproteins E6 and E7. A virus-encoded transcription factor, E2, is known to repress E6\\/E7 expression in HPV-positive cancer cells, leading to growth inhibition, which indicates that E6\\/E7 is required for the survival of the cells. We found that the E2-mediated

Akiko Nishimura; Tomomi Nakahara; Takaharu Ueno; Kenta Sasaki; Satoshi Yoshida; Satoru Kyo; Peter M. Howley; Hiroyuki Sakai

2006-01-01

13

Cyclooxygenase-2 transcription is regulated by human papillomavirus 16 E6 and E7 oncoproteins: evidence of a corepressor/coactivator exchange.  

PubMed

Cyclooxygenase (COX-2) is overexpressed in human papillomavirus (HPV)-induced diseases, including cervical cancer. Although HPV E6 and E7 oncoproteins have been causally linked to cervical carcinogenesis, their effects on COX-2 gene expression are unknown. Increased levels of COX-2 mRNA, protein, and prostaglandin E(2) synthesis were detected in HPV16 E6- and E7-expressing cervical cancer cells (CaSki and SiHa) compared with an uninfected cervical cancer cell line (C33A). HPV16 E6 and E7 oncoproteins induced COX-2 transcription by activating the epidermal growth factor receptor (EGFR)-->Ras-->mitogen-activated protein kinase pathway. Interestingly, HPV16 oncoproteins stimulated EGFR signaling, in part, by inducing the release of amphiregulin, an EGFR ligand. The inductive effects of HPV16 E6 and E7 were mediated by enhanced binding of activator protein-1 to the cyclic AMP (cAMP)-responsive element (-59/-53) of the COX-2 promoter. The potential contribution of coactivators and corepressors to HPV16 E6- and E7-mediated induction of COX-2 was also investigated. Chromatin immunoprecipitation assays indicated that E6 and E7 oncoproteins induced the recruitment of phosphorylated c-Jun, c-Fos, UbcH5, and cAMP-responsive element binding protein-binding protein/p300 to the COX-2 promoter. In contrast, E6 and E7 inhibited the binding of the histone deacetylase 3-nuclear receptor corepressor (NCoR) complex to the COX-2 promoter. Moreover, overexpression of NCoR blocked E6- and E7-mediated stimulation of the COX-2 promoter. Taken together, these results indicate that HPV16 E6 and E7 oncoproteins stimulated COX-2 transcription by inducing a corepressor/coactivator exchange. To our knowledge, this study also provides the first evidence that NCoR can function as a repressor of COX-2 gene expression. PMID:17440114

Subbaramaiah, Kotha; Dannenberg, Andrew J

2007-04-15

14

Identification of the nuclear localization and export signals of high risk HPV16 E7 oncoprotein  

SciTech Connect

The E7 oncoprotein of high risk human papillomavirus type 16 (HPV16) binds and inactivates the retinoblastoma (RB) family of proteins. Our previous studies suggested that HPV16 E7 enters the nucleus via a novel Ran-dependent pathway independent of the nuclear import receptors (Angeline, M., Merle, E., and Moroianu, J. (2003). The E7 oncoprotein of high-risk human papillomavirus type 16 enters the nucleus via a nonclassical Ran-dependent pathway. Virology 317(1), 13-23.). Here, analysis of the localization of specific E7 mutants revealed that the nuclear localization of E7 is independent of its interaction with pRB or of its phosphorylation by CKII. Fluorescence microscopy analysis of enhanced green fluorescent protein (EGFP) and 2xEGFP fusions with E7 and E7 domains in HeLa cells revealed that E7 contains a novel nuclear localization signal (NLS) in the N-terminal domain (aa 1-37). Interestingly, treatment of transfected HeLa cells with two specific nuclear export inhibitors, Leptomycin B and ratjadone, changed the localization of 2xEGFP-E7{sub 38-98} from cytoplasmic to mostly nuclear. These data suggest the presence of a leucine-rich nuclear export signal (NES) and a second NLS in the C-terminal domain of E7 (aa 38-98). Mutagenesis of critical amino acids in the putative NES sequence ({sub 76}IRTLEDLLM{sub 84}) changed the localization of 2xEGFP-E7{sub 38-98} from cytoplasmic to mostly nuclear suggesting that this is a functional NES. The presence of both NLSs and an NES suggests that HPV16 E7 shuttles between the cytoplasm and nucleus which is consistent with E7 having functions in both of these cell compartments.

Knapp, Alixandra A.; McManus, Patrick M.; Bockstall, Katy [Biology Department, Boston College, Higgins Hall, Room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States); Moroianu, Junona [Biology Department, Boston College, Higgins Hall, Room 578, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States)], E-mail: moroianu@bc.edu

2009-01-05

15

Expression of the human papillomavirus type 16 E7 oncoprotein induces an autophagy-related process and sensitizes normal human keratinocytes to cell death in response to growth factor deprivation  

SciTech Connect

Expression of oncogenes, such as the human papillomavirus type 16 (HPV16) E7 oncoprotein, promotes aberrant cell proliferation. In the absence of concurrent mitogenic stimuli, this triggers a cell-intrinsic defense mechanism, the 'trophic sentinel response', which eliminates such aberrant cells. The molecular pathways that elicit this response, however, remain obscure. We set up an experimental system to investigate the trophic sentinel pathway triggered by HPV16 E7 expression in normal human keratinocytes, the natural host cells of HPVs. Keratinocytes expressing HPV16 E7 cultured in E-medium undergo cell death and show increased sub-G1 DNA content when grown to confluence or under conditions of serum deprivation. Moreover, HPV16 E7 expressing human keratinocytes express higher levels of the autophagy marker, LC3-II, which can be abrogated by 3-methyladenine, an autophagy inhibitor. These findings indicate that even under normal culture conditions, HPV16 E7 expression triggers metabolic stress that may result in autophagy, a pathway implicated in carcinogenesis.

Zhou Xiaobo [Infectious Diseases Division, Channing Laboratories, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School (United States); Muenger, Karl [Infectious Diseases Division, Channing Laboratories, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School (United States)], E-mail: kmunger@rics.bwh.harvard.edu

2009-03-01

16

Requirement of E7 oncoprotein for viability of HeLa cells.  

PubMed

Most human papillomavirus (HPV)-positive cervical cancers contain integrated copies of the viral genome in their chromosomes and express the viral oncoproteins E6 and E7. A virus-encoded transcription factor, E2, is known to repress E6/E7 expression in HPV-positive cancer cells, leading to growth inhibition, which indicates that E6/E7 is required for the survival of the cells. We found that the E2-mediated growth inhibition of HeLa cells, an HPV18-positive cancer cell line, was coupled with a reduction in telomerase activity, an effect which was rescued by the complementation of E7 expression, but not E6 expression, indicating that the cell viability and the telomerase activity in HeLa cells are maintained by an E7-associated function. Analysis of E7 mutants suggested that the binding to the pRB family of pocket proteins was involved in the ability of E7 to rescue the growth potential and telomerase activity inhibited by E2 expression. We also showed that the telomerase activity upregulated by E7 expression was determined by the hTERT promoter activity, and that c-Myc upregulation caused by pRB inactivation could account for the promoter activity. The activation of p53 and consequent accumulation of p21Cip1, which were triggered by the downregulation of E6, appeared not to be essential for the E2-mediated growth arrest. PMID:16500131

Nishimura, Akiko; Nakahara, Tomomi; Ueno, Takaharu; Sasaki, Kenta; Yoshida, Satoshi; Kyo, Satoru; Howley, Peter M; Sakai, Hiroyuki

2006-04-01

17

Computer-aided analysis of structural properties and epitopes of Iranian HPV-16 E7 oncoprotein.  

PubMed

Infection by human papillomavirus type 16 (HPV-16) is the cause of 50% or more of cervical cancers in women. The E7 oncoprotein of HPV-16 has long been known as a potent immortalizing and transforming agent. We used different servers like PseAAC, MHC_binding, MHC_II_binding and Expasy for the present computational prediction. The results for T cell epitopes showed that B1501, A0203, A0201, A0202, A6801 and DRB0405 alleles had lower IC50 than other alleles. We also predicted several peptides with the best binding affinities for alleles of the most frequent MHC class I and II alleles of the various ethnic groups living in the different region of Iran. Two peptides (26-35) and (44-52) were predicted as B-cell epitopes. According to this analysis 1 N-glycosylation site, 2 PKC sites, 4 CK2 sites and 3 disulfide sites were predicted. Our computational study predicted that B cell epitope 1 was Casein kinase II phosphorylated (site No. 31) and glycosylated (site No. 29). Putative MHC-I epitopes 3 and 5 and MHC-II epitopes 19, 21 and 26 were predicted to be casein kinase II phosphorylated. MHC-II epitopes 19 and 21 was predicted to be glycosylated. T cell epitopes 1, 13, 16 and 24 were demonstrated to be kinase C phosphorylated. The result of this analysis for Iranian HPV-16 E7 also indicated that 21.43%, 18.37% and 60.20% of the protein were in the ?-helix, extended strand and random coil respectively. PMID:21153780

Moosavi, Fatemeh; Mohabatkar, Hassan; Mohsenzadeh, Sasan

2010-12-01

18

Human papillomavirus type 16 E7 oncoprotein engages but does not abrogate the mitotic spindle assembly checkpoint.  

PubMed

The mitotic spindle assembly checkpoint (SAC) ensures faithful chromosome segregation during mitosis by censoring kinetochore-microtubule interactions. It is frequently rendered dysfunctional during carcinogenesis causing chromosome missegregation and genomic instability. There are conflicting reports whether the HPV16 E7 oncoprotein drives chromosomal instability by abolishing the SAC. Here we report that degradation of mitotic cyclins is impaired in cells with HPV16 E7 expression. RNAi-mediated depletion of Mad2 or BubR1 indicated the involvement of the SAC, suggesting that HPV16 E7 expression causes sustained SAC engagement. Mutational analyses revealed that HPV16 E7 sequences that are necessary for retinoblastoma tumor suppressor protein binding as well as sequences previously implicated in binding the nuclear and mitotic apparatus (NuMA) protein and in delocalizing dynein from the mitotic spindle contribute to SAC engagement. Importantly, however, HPV16 E7 does not markedly compromise the SAC response to microtubule poisons. PMID:22748180

Yu, Yueyang; Munger, Karl

2012-10-10

19

Subcellular localization of the human papillomavirus 16 E7 oncoprotein in CaSki cells and its detection in cervical adenocarcinoma and adenocarcinoma in situ  

PubMed Central

E7 is the major oncoprotein of high-risk human papillomaviruses (HPV) which causes cervical cancer. To date E7 oncoproteins have not been investigated in cervical adenocarcinoma. In this study we generated a rabbit monoclonal anti-HPV-16 E7 antibody, RabMab42-3, which recognizes a conformational epitope in the E7 carboxy-terminal zinc-finger resulting in a strong increase in the sensitivity for the detection of cell-associated HPV-16 E7 protein relative to conventional polyclonal anti-HPV-16 E7 antibodies. Using RabMab42-3, we show that the subcellular localization of endogenous HPV-16 E7 oncoprotein varies during the cell cycle in cervical cancer cells. Moreover, we demonstrate for the first time that the HPV-16 E7 oncoprotein is abundantly expressed in cervical adenocarcinoma in situ and adenocarcinoma, suggesting an important role of HPV-16 E7 for the development of these tumors. Our findings suggest that the HPV-16 E7 oncoprotein could be a useful marker for the detection of cervical adenocarcinoma and their precursors. PMID:20970819

Dreier, Kerstin; Scheiden, René; Lener, Barbara; Ehehalt, Daniela; Pircher, Haymo; Müller-Holzner, Elisabeth; Rostek, Ursula; Kaiser, Andreas; Fiedler, Marc; Ressler, Sigrun; Lechner, Stefan; Widschwendter, Andreas; Even, Jos; Capesius, Catherine; Jansen-Dürr, Pidder; Zwerschke, Werner

2011-01-01

20

The human papilloma virus-16 E7 oncoprotein is able to bind to the retinoblastoma gene product.  

PubMed

Deletions or mutations of the retinoblastoma gene, RB1, are common features of many tumors and tumor cell lines. Recently, the RB1 gene product, p105-RB, has been shown to form stable protein/protein complexes with the oncoproteins of two DNA tumor viruses, the adenovirus E1A proteins and the simian virus 40 (SV40) large T antigen. Neither of these viruses is thought to be associated with human cancer, but they can cause tumors in rodents. Binding between the RB anti-oncoprotein and the adenovirus or SV40 oncoprotein can be recapitulated in vitro with coimmunoprecipitation mixing assays. These assays have been used to demonstrate that the E7 oncoprotein of the human papilloma virus type-16 can form similar complexes with p105-RB. Human papilloma virus-16 is found associated with approximately 50 percent of cervical carcinomas. These results suggest that these three DNA viruses may utilize similar mechanisms in transformation and implicate RB binding as a possible step in human papilloma virus-associated carcinogenesis. PMID:2537532

Dyson, N; Howley, P M; Münger, K; Harlow, E

1989-02-17

21

Human Papillomavirus Type 16 E6 and E7 Oncoproteins Act Synergistically to Cause Head and Neck Cancer in Mice  

PubMed Central

High-risk human papillomaviruses (HPVs) contribute to cervical and other anogenital cancers, and they are also linked etiologically to a subset of head and neck squamous cell carcinomas (HNSCC). We previously established a model for HPV-associated HNSCC in which we treated transgenic mice expressing the papillomaviral oncoproteins with the chemical carcinogen 4-nitroquinoline-1-oxide (4-NQO). We found that the HPV-16 E7 oncoprotein was highly potent in causing HNSCC, and its dominance masked any potential oncogenic contribution of E6, a second papillomaviral oncoprotein commonly expressed in human cancers. In the current study, we shortened the duration of treatment with 4-NQO to reduce the incidence of cancers and discovered a striking synergy between E6 and E7 in causing HNSCC. Comparing the oncogenic properties of wild-type versus mutant E6 genes in this model for HNSCC uncovered a role for some but not other cellular targets of E6 previously shown to contribute to cervical cancer. PMID:20797753

Jabbar, Sean; Strati, Katerina; Shin, Myeong Kyun; Pitot, Henry C.; Lambert, Paul F.

2010-01-01

22

Human papillomavirus type 16 E6 and E7 oncoproteins upregulate c-IAP2 gene expression and confer resistance to apoptosis.  

PubMed

Inhibition of apoptosis plays an important role in the cellular immortalization and transformation induced by E6 and E7 oncoproteins of human papillomavirus (HPV). Here, we report that the transcription of the inhibitor of apoptosis gene, cellular inhibitor of apoptosis protein 2, (c-IAP2), is significantly upregulated in HPV16 E6/E7-immortalized human oral keratinocytes (HOK16E6E7). Overexpression of E6/E7 from the high-risk HPV16 or 18, but not from the low-risk HPV6, activated c-IAP2 promoter. E6 from HPV16 and 18 played a major role in the activation. In addition, the induction of c-IAP2 transcription required nuclear factor-kappaB activity. Overexpression of c-IAP2 in normal human oral keratinocyte conferred resistance to tumor necrosis factor-alpha (TNF-alpha)/cycloheximide (CHX)-induced apoptosis, suggesting the increased c-IAP2 expression in HOK16E6E7 may protect the cells from TNF-alpha-mediated cell death. Moreover, depletion of endogenous c-IAP2 using RNA interference in HOK16E6E7 induced apoptosis, indicating that c-IAP2 is necessary for HPV16 E6/E7-induced resistance to apoptosis and cell survival. Of note, high levels of c-IAP2 transcription were found in several HPV16- or HPV18-positive cancer cells, and depletion of c-IAP2 caused cell death in HPV18-positive HeLa cells. Thus, upregulation of c-IAP2 by E6 and E7 may confer resistance to apoptosis that is necessary for sustained growth of some HPV16- and HPV18-positive cancer cells. PMID:15856013

Yuan, Huidong; Fu, Fenghua; Zhuo, Jiaying; Wang, Wei; Nishitani, Junko; An, Dong Sung; Chen, Irvin S Y; Liu, Xuan

2005-07-28

23

Human papillomavirus 16 oncoprotein E7 stimulates UBF1-mediated rDNA gene transcription, inhibiting a p53-independent activity of p14ARF.  

PubMed

High-risk human papillomavirus oncoproteins E6 and E7 play a major role in HPV-related cancers. One of the main functions of E7 is the degradation of pRb, while E6 promotes the degradation of p53, inactivating the p14ARF-p53 pathway. pRb and p14ARF can repress ribosomal DNA (rDNA) transcription in part by targeting the Upstream Binding Factor 1 (UBF1), a key factor in the activation of RNA polymerase I machinery. We showed, through ectopic expression and siRNA silencing of p14ARF and/or E7, that E7 stimulates UBF1-mediated rDNA gene transcription, partly because of increased levels of phosphorylated UBF1, preventing the inhibitory function of p14ARF. Unexpectedly, activation of rDNA gene transcription was higher in cells co-expressing p14ARF and E7, compared to cells expressing E7 alone. We did not find a difference in P-UBF1 levels that could explain this data. However, p14ARF expression induced E7 to accumulate into the nucleolus, where rDNA transcription takes place, providing an opportunity for E7 to interact with nucleolar proteins involved in this process. GST-pull down and co-immunoprecipitation assays showed interactions between p14ARF, UBF1 and E7, although p14ARF and E7 are not able to directly interact. Co-expression of a pRb-binding-deficient mutant (E7C24G) and p14ARF resulted in EC24G nucleolar accumulation, but not in a significant higher activation of rDNA transcription, suggesting that the inactivation of pRb is involved in this phenomenon. Thus, p14ARF fails to prevent E7-mediated UBF1 phosphorylation, but could facilitate nucleolar pRb inactivation by targeting E7 to the nucleolus. While others have reported that p19ARF, the mouse homologue of p14ARF, inhibits some functions of E7, we showed that E7 inhibits a p53-independent function of p14ARF. These results point to a mutually functional interaction between p14ARF and E7 that might partly explain why the sustained p14ARF expression observed in most cervical pre-malignant lesions and malignancies may be ineffective. PMID:24798431

Dichamp, Isabelle; Séité, Paule; Agius, Gérard; Barbarin, Alice; Beby-Defaux, Agnès

2014-01-01

24

Human Papillomavirus 16 Oncoprotein E7 Stimulates UBF1-Mediated rDNA Gene Transcription, Inhibiting a p53-Independent Activity of p14ARF  

PubMed Central

High-risk human papillomavirus oncoproteins E6 and E7 play a major role in HPV-related cancers. One of the main functions of E7 is the degradation of pRb, while E6 promotes the degradation of p53, inactivating the p14ARF-p53 pathway. pRb and p14ARF can repress ribosomal DNA (rDNA) transcription in part by targeting the Upstream Binding Factor 1 (UBF1), a key factor in the activation of RNA polymerase I machinery. We showed, through ectopic expression and siRNA silencing of p14ARF and/or E7, that E7 stimulates UBF1-mediated rDNA gene transcription, partly because of increased levels of phosphorylated UBF1, preventing the inhibitory function of p14ARF. Unexpectedly, activation of rDNA gene transcription was higher in cells co-expressing p14ARF and E7, compared to cells expressing E7 alone. We did not find a difference in P-UBF1 levels that could explain this data. However, p14ARF expression induced E7 to accumulate into the nucleolus, where rDNA transcription takes place, providing an opportunity for E7 to interact with nucleolar proteins involved in this process. GST-pull down and co-immunoprecipitation assays showed interactions between p14ARF, UBF1 and E7, although p14ARF and E7 are not able to directly interact. Co-expression of a pRb-binding-deficient mutant (E7C24G) and p14ARF resulted in EC24G nucleolar accumulation, but not in a significant higher activation of rDNA transcription, suggesting that the inactivation of pRb is involved in this phenomenon. Thus, p14ARF fails to prevent E7-mediated UBF1 phosphorylation, but could facilitate nucleolar pRb inactivation by targeting E7 to the nucleolus. While others have reported that p19ARF, the mouse homologue of p14ARF, inhibits some functions of E7, we showed that E7 inhibits a p53-independent function of p14ARF. These results point to a mutually functional interaction between p14ARF and E7 that might partly explain why the sustained p14ARF expression observed in most cervical pre-malignant lesions and malignancies may be ineffective. PMID:24798431

Dichamp, Isabelle; Séité, Paule; Agius, Gérard; Barbarin, Alice; Beby-Defaux, Agnès

2014-01-01

25

Disruption of repressive p130-DREAM complexes by human papillomavirus 16 E6/E7 oncoproteins is required for cell-cycle progression in cervical cancer cells.  

PubMed

Human papillomaviruses (HPVs) with tropism for mucosal epithelia are the major aetiological factors in cervical cancer. Most cancers are associated with so-called high-risk HPV types, in particular HPV16, and constitutive expression of the HPV16 E6 and E7 oncoproteins is critical for malignant transformation in infected keratinocytes. E6 and E7 bind to and inactivate the cellular tumour suppressors p53 and Rb, respectively, thus delaying differentiation and inducing proliferation in suprabasal keratinocytes to enable HPV replication. One member of the Rb family, p130, appears to be a particularly important target for E7 in promoting S-phase entry. Recent evidence indicates that p130 regulates cell-cycle progression as part of a large protein complex termed DREAM. The composition of DREAM is cell cycle-regulated, associating with E2F4 and p130 in G0/G1 and with the B-myb transcription factor in S/G2. In this study, we addressed whether p130-DREAM is disrupted in HPV16-transformed cervical cancer cells and whether this is a critical function for E6/E7. We found that p130-DREAM was greatly diminished in HPV16-transformed cervical carcinoma cells (CaSki and SiHa) compared with control cell lines; however, when E6/E7 expression was targeted by specific small hairpin RNAs, p130-DREAM was reformed and the cell cycle was arrested. We further demonstrated that the profound G1 arrest in E7-depleted CaSki cells was dependent on p130-DREAM reformation by also targeting the expression of the DREAM component Lin-54 and p130. The results show that continued HPV16 E6/E7 expression is necessary in cervical cancer cells to prevent cell-cycle arrest by a repressive p130-DREAM complex. PMID:21813705

Nor Rashid, Nurshamimi; Yusof, Rohana; Watson, Roger J

2011-11-01

26

Antitumor DNA vaccines based on the expression of human papillomavirus-16 E6\\/E7 oncoproteins genetically fused with the glycoprotein D from herpes simplex virus-1  

Microsoft Academic Search

DNA vaccines encoding the human papillomavirus type-16 (HPV-16) E6 and E7 oncoproteins genetically fused to the human herpes simplex virus type 1 (HSV-1) gD protein were tested in mice for induction of T cell-mediated immunity and protection against tumor cell challenge. Hybrid genes, generated after insertion of E6 or E7-encoding sequences into internal sites of the gD-encoding gene, were transcribed

Marcio O. Lasaro; Mariana O. Diniz; Arturo Reyes-Sandoval; Hildegund C. Ertl; Luis C. S. Ferreira

2005-01-01

27

The high-risk HPV16 E7 oncoprotein mediates interaction between the transcriptional coactivator CBP and the retinoblastoma protein pRb.  

PubMed

The oncoprotein E7 from human papillomavirus (HPV) strains that confer high cancer risk mediates cell transformation by deregulating host cellular processes and activating viral gene expression through recruitment of cellular proteins such as the retinoblastoma protein (pRb) and the cyclic-AMP response element binding binding protein (CBP) and its paralog p300. Here we show that the intrinsically disordered N-terminal region of E7 from high-risk HPV16 binds the TAZ2 domain of CBP with greater affinity than E7 from low-risk HPV6b. HPV E7 and the tumor suppressor p53 compete for binding to TAZ2. The TAZ2 binding site in E7 overlaps the LxCxE motif that is crucial for interaction with pRb. While TAZ2 and pRb compete for binding to a monomeric E7 polypeptide, the full-length E7 dimer mediates an interaction between TAZ2 and pRb by promoting formation of a ternary complex. Cell-based assays show that expression of full-length HPV16 E7 promotes increased pRb acetylation and that this response depends both on the presence of CBP/p300 and on the ability of E7 to form a dimer. These observations suggest a model for the oncogenic effect of high-risk HPV16 E7. The disordered region of one E7 molecule in the homodimer interacts with the pocket domain of pRb, while the same region of the other E7 molecule binds the TAZ2 domain of CBP/p300. Through its ability to dimerize, E7 recruits CBP/p300 and pRb into a ternary complex, bringing the histone acetyltransferase domain of CBP/p300 into proximity to pRb and promoting acetylation, leading to disruption of cell cycle control. PMID:25451029

Jansma, Ariane L; Martinez-Yamout, Maria A; Liao, Rong; Sun, Peiqing; Dyson, H Jane; Wright, Peter E

2014-12-12

28

The Human Papilloma Virus16 E7 Oncoprotein is Able to Bind to the Retinoblastoma Gene Product  

Microsoft Academic Search

Deletions or mutations of the retinoblastoma gene, RB1, are common features of many tumors and tumor cell lines. Recently, the RB1 gene product, p105-RB, has been shown to form stable protein\\/protein complexes with the oncoproteins of two DNA tumor viruses, the adenovirus E1A proteins and the simian virus 40 (SV40) large T antigen. Neither of these viruses is thought to

Nicholas Dyson; Peter M. Howley; Karl Munger; Ed Harlow

1989-01-01

29

E6^E7, a Novel Splice Isoform Protein of Human Papillomavirus 16, Stabilizes Viral E6 and E7 Oncoproteins via HSP90 and GRP78  

PubMed Central

ABSTRACT Transcripts of human papillomavirus 16 (HPV16) E6 and E7 oncogenes undergo alternative RNA splicing to produce multiple splice isoforms. However, the importance of these splice isoforms is poorly understood. Here we report a critical role of E6^E7, a novel isoform containing the 41 N-terminal amino acid (aa) residues of E6 and the 38 C-terminal aa residues of E7, in the regulation of E6 and E7 stability. Through mass spectrometric analysis, we identified that HSP90 and GRP78, which are frequently upregulated in cervical cancer tissues, are two E6^E7-interacting proteins responsible for the stability and function of E6^E7, E6, and E7. Although GRP78 and HSP90 do not bind each other, GRP78, but not HSP90, interacts with E6 and E7. E6^E7 protein, in addition to self-binding, interacts with E6 and E7 in the presence of GRP78 and HSP90, leading to the stabilization of E6 and E7 by prolonging the half-life of each protein. Knocking down E6^E7 expression in HPV16-positive CaSki cells by a splice junction-specific small interfering RNA (siRNA) destabilizes E6 and E7 and prevents cell growth. The same is true for the cells with a GRP78 knockdown or in the presence of an HSP90 inhibitor. Moreover, mapping and alignment analyses for splicing elements in 36 alpha-HPVs (?-HPVs) suggest the possible expression of E6^E7 mostly by other oncogenic or possibly oncogenic ?-HPVs (HPV18, -30, -31, -39, -42, -45, -56, -59, -70, and -73). HPV18 E6^E7 is detectable in HPV18-positive HeLa cells and HPV18-infected raft tissues. All together, our data indicate that viral E6^E7 and cellular GRP78 or HSP90 might be novel targets for cervical cancer therapy. PMID:25691589

Ajiro, Masahiko

2015-01-01

30

The human papillomavirus type 58 E7 oncoprotein modulates cell cycle regulatory proteins and abrogates cell cycle checkpoints  

SciTech Connect

HPV type 58 (HPV-58) is the third most common HPV type in cervical cancer from Eastern Asia, yet little is known about how it promotes carcinogenesis. In this study, we demonstrate that HPV-58 E7 significantly promoted the proliferation and extended the lifespan of primary human keratinocytes (PHKs). HPV-58 E7 abrogated the G1 and the postmitotic checkpoints, although less efficiently than HPV-16 E7. Consistent with these observations, HPV-58 E7 down-regulated the cellular tumor suppressor pRb to a lesser extent than HPV-16 E7. Similar to HPV-16 E7 expressing PHKs, Cdk2 remained active in HPV-58 E7 expressing PHKs despite the presence of elevated levels of p53 and p21. Interestingly, HPV-58 E7 down-regulated p130 more efficiently than HPV-16 E7. Our study demonstrates a correlation between the ability of down-regulating pRb/p130 and abrogating cell cycle checkpoints by HPV-58 E7, which also correlates with the biological risks of cervical cancer progression associated with HPV-58 infection.

Zhang Weifang [Department of Medicine, University of Massachusetts Medical School, Worcester, MA (United States); Department of Microbiology, School of Medicine, Shandong University, Jinan, Shandong (China); Li Jing [Department of Microbiology, School of Medicine, Shandong University, Jinan, Shandong (China); Kanginakudru, Sriramana [Department of Medicine, University of Massachusetts Medical School, Worcester, MA (United States); Zhao Weiming [Department of Microbiology, School of Medicine, Shandong University, Jinan, Shandong (China); Yu Xiuping, E-mail: yuxp@sdu.edu.c [Department of Microbiology, School of Medicine, Shandong University, Jinan, Shandong (China); Chen, Jason J., E-mail: Jason.chen@umassmed.ed [Department of Medicine, University of Massachusetts Medical School, Worcester, MA (United States)

2010-02-05

31

Construction and characterization of recombinant fowlpox viruses expressing human papilloma virus E6 and E7 oncoproteins  

Microsoft Academic Search

Human papilloma virus (HPV)-16 is the most prevalent high-risk mucosal genotype and the expression of the E6 and E7 proteins, which can bind to the p53 and p105Rb host cell-cycle regulatory proteins, is related to its tumorigenicity. Virus-like-particle (VLP)-based immunogens developed recently are successful as prophylactic HPV vaccines. However, given the high number of individuals infected already with HPV and

Eleana Pozzi; Valeria Basavecchia; Carlo Zanotto; Sole Pacchioni; Carlo De Giuli Morghen; Antonia Radaelli

2009-01-01

32

Overexpression of c-erbB-2 and p21 oncoproteins in human radiation-induced skin ulcers  

SciTech Connect

We studied the overexpression of c-erbB-2 and p21 oncoproteins in human radiation-induced skin ulcers using immunohistochemistry. We found that the positive rate of overexpression of c-erbB-2 and p21 oncoproteins was 92.0 and 92.9%, respectively. The overexpression of c-erbB-2 oncoprotein was observed mainly in the cell membrane of squamous epithelial cells and in the cytoplasm of fibroblasts, endothelial cells, leiomyocytes in the media, and in fibrocytes of the adventitia of mesenchymal arterioles. The location of the p21 oncoprotein overexpression was mostly similar to that of c-erbB-2 with stronger staining in the cytoplasm of squamous epithelial cells and weaker staining in mesenchymal arteriolar walls. The overexpression of c-erbB-2 and p21 oncoproteins may be corresponding to the cancer transformation and poor healing of radiation-induced skin ulcers. 6 refs., 2 figs.

Zhao Po, Yang Zhixiang, Wang De-wen [Inst. of Radiation Medicine, Beijing (China)] [and others

1995-12-31

33

Human papillomavirus E7 enhances hypoxia-inducible factor 1-mediated transcription by inhibiting binding of histone deacetylases.  

PubMed

Infection by human papillomaviruses (HPV) leads to the formation of benign lesions, warts, and in some cases, cervical cancer. The formation of these lesions is dependent upon increased expression of proangiogenic factors. Angiogenesis is linked to tissue hypoxia through the activity of the oxygen-sensitive hypoxia-inducible factor 1? (HIF-1?). Our studies indicate that the HPV E7 protein enhances HIF-1 transcriptional activity whereas E6 functions to counteract the repressive effects of p53. Both high- and low-risk HPV E7 proteins were found to bind to HIF-1? through a domain located in the N-terminus. Importantly, the ability of E7 to enhance HIF-1 activity mapped to the C-terminus and correlated with the displacement of the histone deacetylases HDAC1, HDAC4, and HDAC7 from HIF-1? by E7. Our findings describe a novel role of the E7 oncoprotein in activating the function of a key transcription factor mediating hypoxic responses by blocking the binding of HDACs. PMID:21148070

Bodily, Jason M; Mehta, Kavi P M; Laimins, Laimonis A

2011-02-01

34

Human papillomavirus oncoproteins and apoptosis (Review).  

PubMed

The aim of this study was to review the literature and identify the association between human papillomavirus (HPV) oncoproteins and apoptosis. HPV-associated apoptosis may be primarily blocked by a number of oncoproteins, including E5, E6 and E7. E5 protein protects cells from tumor necrosis factor-associated apoptosis; the oncoprotein E6 predominantly inhibits apoptosis through the p53 pathway; and oncoprotein E7 is involved in apoptosis activation and inhibition. In addition, HPV oncoproteins are involved in activating or repressing the transcription of E6/E7. In conclusion, HPV oncoproteins, including E5, E6 and E7 protein, may interfere with apoptosis via certain regulatory principles. PMID:24348754

Jiang, Peiyue; Yue, Ying

2014-01-01

35

Translation of the human papillomavirus type 16 E7 oncoprotein from bicistronic mRNA is independent of splicing events within the E6 open reading frame.  

PubMed Central

In this study we investigated the translational capacities of bicistronic and spliced mRNAs originating from the E6 and E7 regions of the high-risk genital human papillomavirus type 16 (HPV-16) and the low-risk HPV-11. For HPV-16 it was found, unexpectedly, that E7 protein could be translated from full-length bicistronic E6-E7 mRNAs. E6*I and E6*II splicing events were not required for E7 synthesis, nor did splicing increase the efficiency of E7 translation significantly. In cells, E7 synthesis from all known naturally occurring mRNA structures was very inefficient compared with that from synthetic monocistronic controls, suggesting that HPV-16 employs translational mechanisms to restrict E7 protein levels. For HPV-11, only RNAs initiated at the P264 promoter, located within the E6 open reading frame, were capable of providing an efficient template for E7 synthesis. P264-initiated mRNAs were as efficient in vivo as monocistronic controls, suggesting that the low-risk HPV-11 does not limit E7 synthesis by translational mechanisms. A detailed analysis of HPV-16 templates by using site-directed mutagenesis showed that the majority of ribosomes which ultimately translate E7 have not reinitiated after translating some or all of the upstream open reading frames. The data support a model in which the failure of 40S ribosomal initiation complexes to recognize the E6 AUG renders them capable of proceeding efficiently to translate E7. PMID:7474122

Stacey, S N; Jordan, D; Snijders, P J; Mackett, M; Walboomers, J M; Arrand, J R

1995-01-01

36

Berberine alters epigenetic modifications, disrupts microtubule network, and modulates HPV-18 E6-E7 oncoproteins by targeting p53 in cervical cancer cell HeLa: a mechanistic study including molecular docking.  

PubMed

Increased evidence of chemo-resistance, toxicity and carcinogenicity necessitates search for alternative approaches for determining next generation cancer therapeutics and targets. We therefore tested the efficacy of plant alkaloid berberine on human papilloma virus (HPV) -18 positive cervical cancer cell HeLa systematically-involving certain cellular, viral and epigenetic factors. We observed disruptions of microtubule network and changes in membrane topology due to berberine influx through confocal and atomic force microscopies (AFM). We examined nuclear uptake, internucleosomal DNA damages, mitochondrial membrane potential (MMP) alterations and cell migration assays to validate possible mode of cell death events. Analytical data on interactions of berberine with pBR322 through fourier transform infrared (FTIR) and gel migration assay strengthen berberine?s biologically significant DNA binding abilities. We measured cellular uptake, DNA ploidy and DNA strand-breaks through fluorescence activated cell sorting (FACS). To elucidate epigenetic modifications, in support of DNA binding associated processes, if any, we conducted methylation-specific restriction enzyme (RE) assay, methylation specific-PCR (MSP) and expression studies of histone proteins. We also analyzed differential interactions and localization of cellular tumor suppressor p53 and viral oncoproteins HPV-18 E6-E7 through siRNA approach. We further made in-silico approaches to determine possible binding sites of berberine on histone proteins. Overall results indicated cellular uptake of berberine through cell membrane depolarization causing disruption of microtubule networks and its biological DNA binding abilities that probably contributed to epigenetic modifications. Results of modulation in p53 and viral oncoproteins HPV-18 E6-E7 by berberine further proved its potential as a promising chemotherapeutic agent in cervical cancer. PMID:25448308

Saha, Santu Kumar; Khuda-Bukhsh, Anisur Rahman

2014-12-01

37

HPV16 Oncoproteins Induce MMPs/RECK-TIMP-2 Imbalance in Primary Keratinocytes: Possible Implications in Cervical Carcinogenesis  

PubMed Central

Cervical cancer is the third most common cancer in women worldwide. Persistent infection with high-risk HPV types, principally HPV16 and 18 is the main risk factor for the development of this malignancy. However, the onset of invasive tumor occurs many years after initial exposure in a minority of infected women. This suggests that other factors beyond viral infection are necessary for tumor establishment and progression. Tumor progression is characterized by an increase in secretion and activation of matrix metalloproteinases (MMPs) produced by either the tumor cells themselves or tumor-associated fibroblasts or macrophages. Increased MMPs expression, including MMP-2, MMP-9 and MT1-MMP, has been observed during cervical carcinoma progression. These proteins have been associated with degradation of ECM components, tumor invasion, metastasis and recurrence. However, few studies have evaluated the interplay between HPV infection and the expression and activity of MMPs and their regulators in cervical cancer. We analyzed the effect of HPV16 oncoproteins on the expression and activity of MMP-2, MMP-9, MT1-MMP, and their inhibitors TIMP-2 and RECK in cultures of human keratinocytes. We observed that E7 expression is associated with increased pro-MMP-9 activity in the epithelial component of organotypic cultures, while E6 and E7 oncoproteins co-expression down-regulates RECK and TIMP-2 levels in organotypic and monolayers cultures. Finally, a study conducted in human cervical tissues showed a decrease in RECK expression levels in precancer and cancer lesions. Our results indicate that HPV oncoproteins promote MMPs/RECK-TIMP-2 imbalance which may be involved in HPV-associated lesions outcome. PMID:22438955

Cardeal, Laura Beatriz da Silva; Boccardo, Enrique; Termini, Lara; Rabachini, Tatiana; Andreoli, Maria Antonieta; di Loreto, Celso; Filho, Adhemar Longatto; Villa, Luisa Lina; Maria-Engler, Silvya Stuchi

2012-01-01

38

A Chlamydomonas-Derived Human Papillomavirus 16 E7 Vaccine Induces Specific Tumor Protection  

PubMed Central

Background The E7 protein of the Human Papillomavirus (HPV) type 16, being involved in malignant cellular transformation, represents a key antigen for developing therapeutic vaccines against HPV-related lesions and cancers. Recombinant production of this vaccine antigen in an active form and in compliance with good manufacturing practices (GMP) plays a crucial role for developing effective vaccines. E7-based therapeutic vaccines produced in plants have been shown to be active in tumor regression and protection in pre-clinical models. However, some drawbacks of in whole-plant vaccine production encouraged us to explore the production of the E7-based therapeutic vaccine in Chlamydomonas reinhardtii, an organism easy to grow and transform and fully amenable to GMP guidelines. Methodology/Principal Findings An expression cassette encoding E7GGG, a mutated, attenuated form of the E7 oncoprotein, alone or as a fusion with affinity tags (His6 or FLAG), under the control of the C. reinhardtii chloroplast psbD 5? UTR and the psbA 3? UTR, was introduced into the C. reinhardtii chloroplast genome by homologous recombination. The protein was mostly soluble and reached 0.12% of total soluble proteins. Affinity purification was optimized and performed for both tagged forms. Induction of specific anti-E7 IgGs and E7-specific T-cell proliferation were detected in C57BL/6 mice vaccinated with total Chlamydomonas extract and with affinity-purified protein. High levels of tumor protection were achieved after challenge with a tumor cell line expressing the E7 protein. Conclusions The C. reinhardtii chloroplast is a suitable expression system for the production of the E7GGG protein, in a soluble, immunogenic form. The production in contained and sterile conditions highlights the potential of microalgae as alternative platforms for the production of vaccines for human uses. PMID:23626690

Demurtas, Olivia C.; Massa, Silvia; Ferrante, Paola; Venuti, Aldo; Franconi, Rosella; Giuliano, Giovanni

2013-01-01

39

Transcriptional regulation of genes involved in keratinocyte differentiation by human papillomavirus 16 oncoproteins.  

PubMed

The life cycle of human papillomaviruses (HPVs) is strictly linked to the differentiation of their natural host cells. The HPV E6 and E7 oncoproteins can delay the normal differentiation program of keratinocytes; however, the exact mechanisms responsible for this have not yet been identified. The goal of this study was to investigate the effects of HPV16 oncoproteins on the expression of genes involved in keratinocyte differentiation. Primary human keratinocytes transduced by LXSN (control) retroviruses or virus vectors expressing HPV16 E6, E7 or E6/E7 genes were subjected to gene expression profiling. The results of microarray analysis showed that HPV 16 E6 and E7 have the capacity to downregulate the expression of several genes involved in keratinocyte differentiation. Quantitative real-time polymerase chain reaction (qRT-PCR) assays were performed to confirm the microarray data. To investigate the effects of the HPV oncoproteins on the promoters of selected keratinocyte differentiation genes, luciferase reporter assays were performed. Our results suggest that the HPV 16 E6 and/or E7 oncogenes are able to downregulate the expression of several genes involved in keratinocyte differentiation (such as desmocollin 1, keratin 4, S100 calcium-binding protein A8 and small proline-rich protein 1A), at least partially by downregulating their promoter activity. This activity of the HPV oncoproteins may have a role in the productive virus life cycle, and also in virus-induced carcinogenesis. PMID:25488293

Gyöngyösi, Eszter; Szalmás, Anita; Ferenczi, Annamária; Póliska, Szilárd; Kónya, József; Veress, György

2015-02-01

40

Apoptosis induced by an antagonist peptide against HPV16 E7 in vitro and in vivo via restoration of p53  

Microsoft Academic Search

Human papilloma virus type 16 (HPV16) E7 is a viral oncoprotein that is believed to play a major role in cervical neoplasia.\\u000a A novel antagonist peptide against HPV16 E7 was previously selected by phage display screening and the selected peptide was\\u000a found to have anti-tumor efficacy against HPV16-positive cervical carcinoma through induction of cell cycle arrest. In the\\u000a current study,

Caiping GuoKewei; Kewei Liu; Yi Zheng; Haibo Luo; Hongbo Chen; Laiqiang Huang

2011-01-01

41

Twist and Epithelial-Mesenchymal Transition Are Induced by the EBV Oncoprotein Latent Membrane Protein 1 and Are Associated with Metastatic Nasopharyngeal Carcinoma  

Microsoft Academic Search

Nasopharyngeal carcinoma (NPC), an EBV-associated malig- nancy, is highly metastatic compared with other head and neck tumors, perhaps because of its viral link. Here, we show that the principal EBV oncoprotein, latent membrane protein 1 (LMP1), induces epithelial-mesenchymal transition (EMT) via Twist, a master transcriptional regulator in embryogenesis and newly implicated in metastasis, which, in turn, are likely to contribute

Toshiyuki Horikawa; Jing Yang; Satoru Kondo; Tomokazu Yoshizaki; Irene Joab; Mitsuru Furukawa

42

The HPV-16 E7 oncogene sensitizes malignant cells to IFN-alpha-induced apoptosis  

SciTech Connect

Interferons (IFNs) exert antitumor effects in several human malignancies, but their mechanism of action is unclear. There is a great variability in sensitivity to IFN treatment depending on both tumor type and the individual patient. The reason for this variable sensitivity is not known. The fact that several IFN-induced anticellular effects are exerted through modulation of proto-oncogenes and tumor suppressor genes may indicate that the malignant genotype may be decisive in the cell's sensitivity to IFN. To determine if a deregulated oncogene could alter the cellular response to IFN, a mouse lymphoma cell line (J3D) was stably transfected with the viral human papillomavirus-16 (HPV-16) E7 oncogene. The E7-transfected cells and their respective mock-transfected sister clones were treated with IFN-{alpha} and examined for possible IFN-induced anticellular effects. We found that the E7-transfected clones were greatly sensitized to IFN-{alpha}-induced apoptosis compared with their mock-transfected counterparts. Induction of apoptosis in the transfected cells correlated with the ability of IFN to activate parts of the proapoptotic machinery specifically in these cells, including activation of caspases and the proapoptotic protein Bak. In summary, our data suggest that transfection of malignant cells with the E7 oncogene can sensitize them to IFN-{alpha}-induced apoptosis. This demonstrates that an oncogenic event may alter the cellular sensitivity to IFN and might also have implications for treatment of HPV related diseases with IFN.

Wang, Yisong [ORNL

2005-10-01

43

Papillomavirus E6 oncoproteins.  

PubMed

Papillomaviruses induce benign and malignant epithelial tumors, and the viral E6 oncoprotein is essential for full transformation. E6 contributes to transformation by associating with cellular proteins, docking on specific acidic LXXLL peptide motifs found on these proteins. This review examines insights from recent studies of human and animal E6 proteins that determine the three-dimensional structure of E6 when bound to acidic LXXLL peptides. The structure of E6 is related to recent advances in the purification and identification of E6 associated protein complexes. These E6 protein-complexes, together with other proteins that bind to E6, alter a broad array of biological outcomes including modulation of cell survival, cellular transcription, host cell differentiation, growth factor dependence, DNA damage responses, and cell cycle progression. PMID:23711382

Vande Pol, Scott B; Klingelhutz, Aloysius J

2013-10-01

44

Twist and epithelial-mesenchymal transition are induced by the EBV oncoprotein latent membrane protein 1 and are associated with metastatic nasopharyngeal carcinoma.  

PubMed

Nasopharyngeal carcinoma (NPC), an EBV-associated malignancy, is highly metastatic compared with other head and neck tumors, perhaps because of its viral link. Here, we show that the principal EBV oncoprotein, latent membrane protein 1 (LMP1), induces epithelial-mesenchymal transition (EMT) via Twist, a master transcriptional regulator in embryogenesis and newly implicated in metastasis, which, in turn, are likely to contribute to the highly metastatic character of NPC. LMP1 could induce EMT and its associated cell motility and invasiveness in a cell culture model, whereas expression of Twist small interfering RNA reversed LMP1-induced EMT. In diverse EBV-infected cell lines, expression of Twist correlates with expression of LMP1. Dominant-negative LMP1 could suppress Twist expression in EBV-positive cells, whereas LMP1 could induce Twist in EBV-negative nasopharyngeal cells. LMP1 signals through the nuclear factor-kappaB pathway, and an IkappaB superrepressor inhibited induction of Twist by LMP1. Finally, in human NPC tissues, expression of Twist and LMP1 is directly correlated and expression of Twist is associated with metastasis clinically. These results suggest that induction of Twist by a human viral oncoprotein LMP1 directly contributes to the metastatic nature of NPC. PMID:17332324

Horikawa, Toshiyuki; Yang, Jing; Kondo, Satoru; Yoshizaki, Tomokazu; Joab, Irene; Furukawa, Mitsuru; Pagano, Joseph S

2007-03-01

45

Reprogramming of plant cells induced by 6b oncoproteins from the plant pathogen Agrobacterium.  

PubMed

Reprogramming of plant cells is an event characterized by dedifferentiation, reacquisition of totipotency, and enhanced cell proliferation, and is typically observed during formation of the callus, which is dependent on plant hormones. The callus-like cell mass, called a crown gall tumor, is induced at the sites of infection by Agrobacterium species through the expression of hormone-synthesizing genes encoded in the T-DNA region, which probably involves a similar reprogramming process. One of the T-DNA genes, 6b, can also by itself induce reprogramming of differentiated cells to generate tumors and is therefore recognized as an oncogene acting in plant cells. The 6b genes belong to a group of Agrobacterium T-DNA genes, which include rolB, rolC, and orf13. These genes encode proteins with weakly conserved sequences and may be derived from a common evolutionary origin. Most of these members can modify plant growth and morphogenesis in various ways, in most cases without affecting the levels of plant hormones. Recent studies have suggested that the molecular function of 6b might be to modify the patterns of transcription in the host nuclei, particularly by directly targeting the host transcription factors or by changing the epigenetic status of the host chromatin through intrinsic histone chaperone activity. In light of the recent findings on zygotic resetting of nucleosomal histone variants in Arabidopsis thaliana, one attractive idea is that acquisition of totipotency might be facilitated by global changes of epigenetic status, which might be induced by replacement of histone variants in the zygote after fertilization and in differentiated cells upon stimulation by plant hormones as well as by expression of the 6b gene. PMID:25694001

Ito, Masaki; Machida, Yasunori

2015-05-01

46

Human papillomavirus oncoproteins: pathways to transformation  

Microsoft Academic Search

An association between human papillomavirus (HPV) infection and the development of cervical cancer was initially reported over 30 years ago, and today there is overwhelming evidence that certain subtypes of HPV are the causative agents of these malignancies. The p53 and retinoblastoma proteins are well-characterized targets of the HPV E6 and E7 oncoproteins, but recent studies have shown that the

Cary A. Moody; Laimonis A. Laimins

2010-01-01

47

A novel hydrophobized polysaccharide/oncoprotein complex vaccine induces in vitro and in vivo cellular and humoral immune responses against HER2-expressing murine sarcomas.  

PubMed

To elicit specific cellular immune responses against cancer, the development of efficient devices to deliver tumor antigen peptides to the MHC class I pathway constitutes a central issue. We report here a novel formula of hydrophobized polysaccharide nanoparticles, which can deliver a HER2 oncoprotein containing an epitope peptide to the MHC class I pathway. A protein consisting of the 147 amino-terminal amino acids of oncogene erbB-2/neu/HER2 (HER2) was complexed with two kinds of hydrophobized polysaccharides, cholesteryl group-bearing mannan (CHM) and cholesteryl group-bearing pullulan (CHP), to form nanoparticles (CHM-HER2 and CHP-HER2). CHM-HER2 and CHP-HER2 were able to induce CD3+/CD8+ CTLs against HER2-transfected syngeneic fibrosarcoma cell lines. In contrast, the oncoprotein alone failed to do so. These CTLs were Kd-restricted and specifically recognized a peptide (position 63-71) that was a part of a truncated HER2 protein used as an immunogen. In addition, vaccination by CHM-HER2 complexes led to a strongly enhanced production of IgG antibodies against HER2, whereas vaccination with HER2 proteins alone resulted in a production of antibodies at a marginal level. Mice immunized with CHM-HER2 or CHP-HER2 before tumor challenge successfully rejected HER2-transfected tumors. The complete rejection of tumors also occurred when CHM-HER2 was applied not later than 3 days after tumor implantation. In the effector phase of in vivo tumor rejection, CD8+ T cells played a major role. The results suggest that a sort of hydrophobized polysaccharide may help soluble proteins to induce cellular immunity as well enhance humoral immunity; hence, such a novel vaccine may be of potential benefit to cancer prevention and cancer therapy. PMID:9699670

Gu, X G; Schmitt, M; Hiasa, A; Nagata, Y; Ikeda, H; Sasaki, Y; Akiyoshi, K; Sunamoto, J; Nakamura, H; Kuribayashi, K; Shiku, H

1998-08-01

48

Inhibition of the MUC1-C oncoprotein induces multiple myeloma cell death by down-regulating TIGAR expression and depleting NADPH.  

PubMed

The MUC1-C oncoprotein is aberrantly expressed in most multiple myeloma cells. However, the functional significance of MUC1-C expression in multiple myeloma is not known. The present studies demonstrate that treatment of multiple myeloma cells with a MUC1-C inhibitor is associated with increases in reactive oxygen species (ROS), oxidation of mitochondrial cardiolipin, and loss of the mitochondrial transmembrane potential. The MUC1-C inhibitor-induced increases in ROS were also associated with down-regulation of the p53-inducible regulator of glycolysis and apoptosis (TIGAR). In concert with the decrease in TIGAR expression, which regulates the pentose phosphate pathway, treatment with the MUC1-C inhibitor reduced production of NADPH, and in turn glutathione (GSH) levels. TIGAR protects against oxidative stress-induced apoptosis. The suppression of TIGAR and NADPH levels thus contributed to ROS-mediated late apoptosis/necrosis of multiple myeloma cells. These findings indicate that multiple myeloma cells are dependent on MUC1-C and TIGAR for maintenance of redox balance and that targeting MUC1-C activates a cascade involving TIGAR suppression that contributes to multiple myeloma cell death. PMID:22117045

Yin, Li; Kosugi, Michio; Kufe, Donald

2012-01-19

49

Codon Optimization of the Human Papillomavirus E7 Oncogene Induces a CD8+ T Cell Response to a Cryptic Epitope Not Harbored by Wild-Type E7  

PubMed Central

Codon optimization of nucleotide sequences is a widely used method to achieve high levels of transgene expression for basic and clinical research. Until now, immunological side effects have not been described. To trigger T cell responses against human papillomavirus, we incubated T cells with dendritic cells that were pulsed with RNA encoding the codon-optimized E7 oncogene. All T cell receptors isolated from responding T cell clones recognized target cells expressing the codon-optimized E7 gene but not the wild type E7 sequence. Epitope mapping revealed recognition of a cryptic epitope from the +3 alternative reading frame of codon-optimized E7, which is not encoded by the wild type E7 sequence. The introduction of a stop codon into the +3 alternative reading frame protected the transgene product from recognition by T cell receptor gene-modified T cells. This is the first experimental study demonstrating that codon optimization can render a transgene artificially immunogenic through generation of a dominant cryptic epitope. This finding may be of great importance for the clinical field of gene therapy to avoid rejection of gene-corrected cells and for the design of DNA- and RNA-based vaccines, where codon optimization may artificially add a strong immunogenic component to the vaccine. PMID:25799237

Lorenz, Felix K. M.; Wilde, Susanne; Voigt, Katrin; Kieback, Elisa; Mosetter, Barbara; Schendel, Dolores J.; Uckert, Wolfgang

2015-01-01

50

E5 oncoprotein retained in the endoplasmic reticulum/cis Golgi still induces PDGF receptor autophosphorylation but does not transform cells.  

PubMed Central

The E5 oncoprotein encoded by bovine papillomavirus type 1 is a homodimeric, hydrophobic polypeptide which is localized predominantly in Golgi membranes and which transforms several cell types apparently by inducing tyrosine phosphorylation of the platelet-derived growth factor receptor (PDGF-R). While the precise mechanism of receptor activation is unknown, E5 associates with several cellular proteins, including PDGF-R and the 16K V-ATPase protein, and induces the preferential phosphorylation of immature, Endo H-sensitive forms of the receptor. To evaluate whether E5 accumulation in the Golgi was requisite for receptor phosphorylation and cell transformation, we sequestered the E5 protein in the endoplasmic reticulum (ER)/cis Golgi by appending the ER retention KDEL sequence to its C-terminus. In transient assays and in cell lines, E5/KDEL protein and E5/KDEL* protein (a defective variant of KDEL), were stable and formed homodimers normally. E5/KDEL*, similar to wt E5, localized to the Golgi and was transformation-proficient. In contrast, E5/KDEL failed to concentrate in the Golgi and was transformation-incompetent. Despite these critical defects, however, E5/KDEL formed stable complexes with immature PDGF-R and 16K and, even more unexpectedly, induced the phosphorylation of both mature and immature PDGF-R on tyrosine residues to the same level as wt E5. These data demonstrate that E5 can bind and induce PDGF-R phosphorylation in the ER/cis Golgi, but that successful mitogenic signalling (and consequent cell transformation) requires the translocation of E5/receptor complexes to distal Golgi compartments. Images PMID:7621820

Sparkowski, J; Anders, J; Schlegel, R

1995-01-01

51

E7-expressing HaCaT keratinocyte cells are resistant to oxidative stress-induced cell death via the induction of catalase.  

PubMed

Cervical carcinoma is one of the most prevalent cancers in women worldwide, and human papillomavirus (HPV) type 16 is the most common agent linked to human cervical carcinoma. In order to identify various relevant factors affected by the E7 oncogene, we established a stable cell line, which constitutively expressed E7 using the HaCaT human keratinocyte cell line. The increased expression and activity of catalase in the E7-expressing HaCaT cells (HaCaT/E7) were verified via matrix-assisted laser desorption/ionization-time of flight, Western blot, and reverse transcription-polymerase chain reaction analyses. The regulation of catalase by E7 was investigated by the detection of catalase promoter activity. E7 enhanced the activities of both the catalase promoter and nuclear factor-kappaB, one of the major transcription factors regulating the expression of the catalase gene. HaCaT/E7 cells produced lower quantities of intracellular reactive oxygen species (ROS), and appeared to be more resistant to H(2)O(2)-induced cell death. Moreover, in order to test the specific effects of E7 on catalase induction, the HaCaT/E7 cells were transiently transfected with E7 antisense vector, resulting in reductions in both the expression and activity of catalase, and a recovery of intracellular ROS levels, thus resulting in recovered sensitivity to H(2)O(2)-induced cell death. These results suggest that the HPV 16 E7 oncogene induces higher resistance to ROS-induced cell injury in the E7-infected cells, probably via the modulation of several anti-oxidant enzymes, including catalase. PMID:15852342

Shim, Jung-Hyun; Cho, Kyung-Joo; Lee, Kyung-Ae; Kim, Soo-Hyun; Myung, Pyung-Keun; Choe, Yong-Kyung; Yoon, Do-Young

2005-05-01

52

A Non-oncogenic HPV 16 E6/E7 Vaccine Enhances Treatment of HPV Expressing Tumors  

PubMed Central

Human papillomaviruses (HPVs) are the causative factor for greater than 90% of cervical cancers and 25% of head and neck cancers. The incidence of HPV positive (+) head and neck squamous cell carcinomas (HNSCCs) has greatly increased in the last 30 years. E6 and E7 are the two key viral oncoproteins that induce and propagate cellular transformation. An immune response generated during cisplatin/radiation therapy improves tumor clearance of HPV(+) cancers. Augmenting this induced response during therapy with an adenoviral HPV16 E6/E7 vaccine improves long term survival in preclinical models. Here we describe the generation of an HPV16 E6/E7 construct, which contains mutations that render E6/E7 non-oncogenic, while preserving antigenicity. These mutations do not allow E6/E7 to degrade p53, pRb, PTPN13, or activate telomerase. Non-oncogenic E6/E7 (E6?/E7?) expressed as a stable integrant, or in the [E1-, E2b-] adenovirus, lacks the ability to transform human cells while retaining the ability to induce an HPV specific immune response. Moreover, E6?/E7? plus chemotherapy/radiation statistically enhances clearance of established HPV(+) cancer in vivo. PMID:22918471

Wieking, Bryant G.; Vermeer, Daniel W.; Spanos, William C.; Lee, Kimberly M.; Vermeer, Paola; Lee, Walter T.; Xu, Younong; Gabitzsch, Elizabeth S.; Balcaitis, Stephanie; Balint, Joseph P.; Jones, Frank R.; Lee, John H.

2012-01-01

53

HTLV-1 Tax Oncoprotein Inhibits the Estrogen-Induced-ER ?-Mediated BRCA1 Expression by Interaction with CBP/p300 Cofactors  

PubMed Central

BRCA1 is a multifunctional tumor suppressor, whose expression is activated by the estrogen (E2)-liganded ER? receptor and regulated by certain recruited transcriptional co-activators. Interference with BRCA1 expression and/or functions leads to high risk of breast or/and ovarian cancer. Another multifunctional protein, HTLV-1Tax oncoprotein, is widely regarded as crucial for developing adult T-cell leukemia and other clinical disorders. Tax profile reveals that it can antagonize BRCA1 expression and/or functionality. Therefore, we hypothesize that Tax expression in breast cells can sensitize them to malignant transformation by environmental carcinogens. Here we examined Tax effect on BRCA1 expression by testing its influence on E2-induced expression of BRCA1 promoter-driven luciferase reporter (BRCA1-Luc). We found that E2 strongly stimulated this reporter expression by liganding to ER?, which consequently associated with BRCA1 promoter, while ER? concomitantly recruited CBP/p300 to this complex for co-operative enhancement of BRCA1 expression. Introducing Tax into these cells strongly blocked this E2-ER?-mediated activation of BRCA1 expression. We noted, also, that Tax exerted this inhibition by binding to CBP/p300 without releasing them from their complex with ER?. Chip assay revealed that the binding of Tax to the CBP/p300-ER? complex, prevented its link to AP1 site. Interestingly, we noted that elevating the intracellular pool of CBP or p300 to excessive levels dramatically reduced the Tax-mediated inhibition of BRCA1 expression. Exploring the mechanism of this reduction revealed that the excessive co-factors were sufficient to bind separately the free Tax molecules, thus lowering their amount in the CBP/p300-ER? complex and relieving, thereby, the inhibition of BRCA1 expression. PMID:24586743

Shukrun, Meital; Jabareen, Azhar; Abou-Kandil, Ammar; Chamias, Rachel; Aboud, Mordechai; Huleihel, Mahmoud

2014-01-01

54

Dihydroartemisinin accelerates c-MYC oncoprotein degradation and induces apoptosis in c-MYC-overexpressing tumor cells.  

PubMed

Artemisinin and its derivatives (ARTs) are effective antimalarial drugs and also possess profound anticancer activity. However, the mechanism accounted for its distinctive activity in tumor cells remains unelucidated. We computed Pair wise Pearson correlation coefficients to identify genes that show significant correlation with ARTs activity in NCI-55 cell lines using data obtained from studies with HG-U133A Affymetrix chip. We found c-myc is one of the genes that showed the highest positive correlation coefficients among the probe sets analyzed (r=0.585, P<0.001). Dihydroartemisinin (DHA), the main active metabolite of ARTs, induced significant apoptosis in HL-60 and HCT116 cells that express high levels of c-MYC. Stable knockdown of c-myc abrogated DHA-induced apoptosis in HCT116 cells. Conversely, forced expression of c-myc in NIH3T3 cells sensitized these cells to DHA-induced apoptosis. Interestingly, DHA irreversibly down-regulated the protein level of c-MYC in DHA-sensitive HCT116 cells, which is consistent to persistent G1 phase arrest induced by DHA. Further studies demonstrated that DHA accelerated the degradation of c-MYC protein and this process was blocked by pretreatment with the proteasome inhibitor MG-132 or GSK 3beta inhibitor LiCl in HCT116 cells. Taken together, ARTs might be useful in the treatment of c-MYC-overexpressing tumors. We also suggest that c-MYC may potentially be a biomarker candidate for prediction of the antitumor efficacies of ARTs. PMID:20206143

Lu, Jin-Jian; Meng, Ling-Hua; Shankavaram, Uma T; Zhu, Cai-Hua; Tong, Lin-Jiang; Chen, Guang; Lin, Li-Ping; Weinstein, John N; Ding, Jian

2010-07-01

55

A novel function of HPV16-E6/E7 in epithelial-mesenchymal transition.  

PubMed

Human papillomavirus (HPV) 16 is among the most important etiological factors in many human cancers, including head and neck squamous cell carcinomas (HNSCCs) not associated with alcohol or tobacco use. HPV16-E6 and E7 oncoproteins target intracellular signaling networks, altering key molecular and cellular events during tumor progression. The present study investigates the role of HPV16-E6 and E7 oncogenes on the epithelial-mesenchymal transition (EMT), a cellular process thought to be critical for tumor cell invasion and metastasis. Using the epithelial MDCK cell line as an in vitro model, we show that the stable expression of HPV16-E6 or E7 induces morphological conversion from cobblestone-shaped epithelium to spindle-shaped mesenchyme-like phenotype. Consistent with these morphological changes, both E6 and E7 induce expression of the EMT-activating transcriptional factors Slug, Twist, ZEB1 and ZEB2, especially ZEBs, accompanied with switch from epithelial to mesenchymal markers. Importantly, E6 and E7 expression results in induction of the migratory and invasive potential, a functional hallmark of EMT. When we examined the association between HPV16 and the EMT signature in HNSCC cell lines derived from head and neck cancer patients, we found a correlation between HPV16 positivity and the expression of EMT transcription factor ZEB1. Taken together, our findings suggest HPV16 induces EMT-like processes via induction of the EMT transcription factors which may contribute to tumor progression and metastasis. PMID:23628416

Jung, Young-Suk; Kato, Ikuko; Kim, Hyeong-Reh Choi

2013-06-01

56

Gene silencing of HPV16 E6\\/E7 induced by promoter-targeting siRNA in SiHa cells  

Microsoft Academic Search

Background:Recently, transcriptional gene silencing induced by small interfering RNA (siRNA) was found in mammalian and human cells. However, previous studies focused on endogenous genes.Methods:In this study, we designed siRNA targeting the promoter of human papillomavirus 16 E6\\/E7 and transfected it into the cervical cancer cell line, SiHa. E6 and E7 mRNA and protein expression were detected in cells treated by

D Hong; W Lu; F Ye; Y Hu; X Xie

2009-01-01

57

Involvement of NF-kappaB and AP-1 in COX-2 upregulation by human papillomavirus 16 E5 oncoprotein.  

PubMed

The human papillomavirus (HPV) E6 and E7 oncoproteins play important roles in cervical carcinogenesis through multiple mechanisms, including upregulation of cyclooxygenase-2 (COX-2), which has been shown to be involved in both carcinogenesis and cancer progression. To explore the role of E5 in cervical carcinogenesis, we herein investigated the effect of HPV 16 E5 on COX-2 expression. Our results revealed that E5 induced COX-2 expression through the epidermal growth factor receptor-signaling pathway, with nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) acting as critical factors in E5-induced COX-2 expression. NF-kappaB inhibition blocked COX-2 expression more potently than inhibition of AP-1. Our findings collectively suggest that the HPV 16 E5 oncoprotein mediates cervical carcinogenesis at least in part via upregulation of COX-2 expression through NF-kappaB and AP-1, with NF-kappaB playing a larger role. PMID:19321801

Kim, Su-Hyeong; Oh, Jung-Min; No, Jae-Hong; Bang, Yung-Jue; Juhnn, Yong-Sung; Song, Yong-Sang

2009-05-01

58

Egg yolk antibodies against the E7 oncogenic protein of human papillomavirus type 16  

Microsoft Academic Search

Summary.  ?The E7 oncoprotein is the major transforming protein of Human Papillomavirus type 16 (HPV16) and the most abundant in cervical\\u000a neoplasia. In this study we report the production of polyclonal antibodies to HPV16 E7 in rabbits and hens. The produced antibodies\\u000a recognised the denatured and native form of HPV16 E7 protein by Western Blot, and immunoprecipitation. Epitope mapping demonstrated\\u000a that

A. Di Lonardo; M. Luisa Marcante; F. Poggiali; E. Hamsøíkovà; A. Venuti

2001-01-01

59

Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells.  

PubMed

Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells. PMID:23955116

Kim, Man Sub; Bak, Yesol; Park, Yun Sun; Lee, Dong Hun; Kim, Jung Hee; Kang, Jeong Woo; Song, Hyuk-Hwan; Oh, Sei-Ryang; Yoon, Do Young

2013-08-01

60

Tobacco Smoke Activates Human Papillomavirus 16 p97 Promoter and Cooperates with High-Risk E6/E7 for Oxidative DNA Damage in Lung Cells  

PubMed Central

We have previously shown a functional interaction between human papillomavirus type 16 (HPV-16) E6 and E7 oncoproteins and cigarette smoke condensate (CSC) in lung cells suggesting cooperation during carcinogenesis. The molecular mechanisms of such interaction, however, remain to be elucidated. Here we first present evidence showing that cigarette smoke condensate (CSC) has the ability to activate the HPV-16 p97 promoter by acting on the long control region (LCR) in lung epithelial cells. Interestingly, we observed that CSC-induced p97 promoter activation occurs in a dose-dependent manner in both tumor A-549 (lung adenocarcinoma), H-2170 (bronchial carcinoma), SiHa or Hela (cervical carcinoma) cells but not in non-tumor BEAS-2B (bronchial) or NL-20 (alveolar) lung cells unless they ectopically expressed the HPV-16 E6 and E7 oncogenes. In addition, we also observed a significant increase of primary DNA damage in tumor and non-tumor CSC-treated lung cells expressing HPV-16 E6 and E7 oncogenes suggesting a cooperative effect in this process, even though the contribution of E7 was significantly higher. Taken together, our results strongly suggest that tobacco smoke is able to induce the activation of the HPV-16 p97 promoter in cooperation with HPV-16 E6 and E7 oncogenes that, in turn, sensitize lung cells to tobacco smoke-induced DNA damage. PMID:25830243

Muñoz, Juan P.; Chnaiderman, Jonás; Urzúa, Ulises; León, Oscar; Tornesello, Maria L.; Corvalán, Alejandro H.; Soto-Rifo, Ricardo; Aguayo, Francisco

2015-01-01

61

The tumor marker Fascin is induced by the Epstein-Barr virus-encoded oncoprotein LMP1 via NF-?B in lymphocytes and contributes to their invasive migration  

PubMed Central

Background The actin-bundling protein Fascin (FSCN1) is a tumor marker that is highly expressed in numerous types of cancer including lymphomas and is important for migration and metastasis of tumor cells. Fascin has also been detected in B lymphocytes that are freshly-infected with Epstein-Barr virus (EBV), however, both the inducers and the mechanisms of Fascin upregulation are still unclear. Results Here we show that the EBV-encoded oncoprotein latent membrane protein 1 (LMP1), a potent regulator of cellular signaling and transformation, is sufficient to induce both Fascin mRNA and protein in lymphocytes. Fascin expression is mainly regulated by LMP1 via the C-terminal activation region 2 (CTAR2). Block of canonical NF-?B signaling using a chemical inhibitor of I?B kinase ? (IKK?) or cotransfection of a dominant-negative inhibitor of I?B? (NFKBIA) reduced not only expression of p100, a classical target of the canonical NF-?B-pathway, but also LMP1-induced Fascin expression. Furthermore, chemical inhibition of IKK? reduced both Fascin mRNA and protein levels in EBV-transformed lymphoblastoid cell lines, indicating that canonical NF-?B signaling is required for LMP1-mediated regulation of Fascin both in transfected and transformed lymphocytes. Beyond that, chemical inhibition of IKK? significantly reduced invasive migration of EBV-transformed lymphoblastoid cells through extracellular matrix. Transient transfection experiments revealed that Fascin contributed to LMP1-mediated enhancement of invasive migration through extracellular matrix. While LMP1 enhanced the number of invaded cells, functional knockdown of Fascin by two different small hairpin RNAs resulted in significant reduction of invaded, non-attached cells. Conclusions Thus, our data show that LMP1-mediated upregulation of Fascin depends on NF-?B and both NF-?B and Fascin contribute to invasive migration of LMP1-expressing lymphocytes. PMID:25105941

2014-01-01

62

HPV16 Oncoproteins Promote Cervical Cancer Invasiveness by Upregulating Specific Matrix Metalloproteinases  

PubMed Central

Production of matrix metalloproteinases (MMPs) for degradation of extracellular matrix is a vital step in cancer metastasis. We investigated the effects of HPV16 oncoproteins (16E6, 16E6*I and 16E7), either individually or combined, on the transcription of 7 MMPs implicated in cervical cancer invasiveness. The levels of 7 MMPs reported to be increased in cervical cancer were determined in C33A stably expressing different HPV16 oncoproteins using quantitative RT-PCR and compared with invasion ability of cell lines using in vitro invasion and wound healing assays. Overexpression of MMP-2 and MT1-MMP was detected in HPV16E6E7 expressing cells which correlated with increased cell invasion. Combination of HPV oncoproteins always showed greater effects than its individual form. Inhibition of cell invasion using a specific MMP-2 inhibitor, OA-Hy, and anti-MT1-MMP antibody confirmed that invasion in these cells was dependent on both MMP-2 and MT1-MMP expression. Depletion of HPV16E6E7 by shRNA-mediated knock-down experiments resulted in decreased MMP-2 and MT1-MMP expression levels as well as reduced invasion ability which strongly suggested specific effects of HPV oncoproteins on both MMPs and on cell invasion. Immunohistochemistry study in invasive cervical cancers confirmed the enhanced in vivo expression of these two MMPs in HPV16-infected cells. In addition, possible sites required by HPV16E6E7 on the MMP-2 and MT1-MMP promoters were investigated and PEA3 (at ?552/?540 for MMP-2, ?303 for MT1-MMP) and Sp1 (at ?91 for MMP-2, ?102 for MT1-MMP) binding sites were shown to be essential for mediating their transactivation activity. In conclusion, our study demonstrated that HPV16E6 and E7 oncoproteins cooperate in promoting cervical cancer invasiveness by specifically upregulating MMP-2 and MT1-MMP transcription in a similar manner. PMID:23967226

Kaewprag, Jittranan; Umnajvijit, Wareerat; Ngamkham, Jarunya; Ponglikitmongkol, Mathurose

2013-01-01

63

The human papillomavirus type 16 E6 oncoprotein activates mTORC1 signaling and increases protein synthesis.  

PubMed

The mammalian target of rapamycin (mTOR) kinase acts as a cellular rheostat that integrates signals from a variety of cellular signal transduction pathways that sense growth factor and nutrient availability as well as intracellular energy status. It was previously reported that the human papillomavirus type 16 (HPV16) E6 oncoprotein may activate the S6 protein kinase (S6K) through binding and E6AP-mediated degradation of the mTOR inhibitor tuberous sclerosis complex 2 (TSC2) (Z. Lu, X. Hu, Y. Li, L. Zheng, Y. Zhou, H. Jiang, T. Ning, Z. Basang, C. Zhang, and Y. Ke, J. Biol. Chem. 279:35664-35670, 2004; L. Zheng, H. Ding, Z. Lu, Y. Li, Y. Pan, T. Ning, and Y. Ke, Genes Cells 13:285-294, 2008). Our results confirmed that HPV16 E6 expression causes an increase in mTORC1 activity through enhanced phosphorylation of mTOR and activation of downstream signaling pathways S6K and eukaryotic initiation factor binding protein 1 (4E-BP1). However, we did not detect a decrease in TSC2 levels in HPV16 E6-expressing cells. We discovered, however, that HPV16 E6 expression causes AKT activation through the upstream kinases PDK1 and mTORC2 under conditions of nutrient deprivation. We show that HPV16 E6 expression causes an increase in protein synthesis by enhancing translation initiation complex assembly at the 5' mRNA cap and an increase in cap-dependent translation. The increase in cap-dependent translation likely results from HPV16 E6-induced AKT/mTORC1 activation, as the assembly of the translation initiation complex and cap-dependent translation are rapamycin sensitive. Lastly, coexpression of the HPV16 E6 and E7 oncoproteins does not affect HPV16 E6-induced activation of mTORC1 and cap-dependent translation. HPV16 E6-mediated activation of mTORC1 signaling and cap-dependent translation may be a mechanism to promote viral replication under conditions of limited nutrient supply in differentiated, HPV oncoprotein-expressing proliferating cells. PMID:20631133

Spangle, Jennifer M; Münger, Karl

2010-09-01

64

ADXS-HPV: A therapeutic Listeria vaccination targeting cervical cancers expressing the HPV E7 antigen.  

PubMed

Listeria monocytogenes is a bacterium that can be genetically modified to express fusion proteins with antigens specific to certain cancer models. This technology has been harnessed to develop ADXS11-001, a vaccine that aims to elicit an immune response against human papillomavirus (HPV) oncoprotein E7.??Pre-clinical studies assessing the efficacy of recombinant Listeria vaccination targeting this same oncoprotein have consistently demonstrated successful reduction of in vivo tumor burden among animal cancer models. Several clinical trials are underway to assess the efficacy of ADXS11-001 in eliciting both immune and clinical responses against HPV-related human cervical, oropharyngeal and anal cancers. PMID:25483687

Cory, Lori; Chu, Christina

2014-11-01

65

Luteolin induces intrinsic apoptosis via inhibition of E6/E7 oncogenes and activation of extrinsic and intrinsic signaling pathways in HPV-18-associated cells.  

PubMed

Luteolin, a flavonoid extracted from a number of plants with recognized anticancer, anti-inflammatory and anti-oxidative activities, inhibits angiogenic processes and modulates multidrug resistance. However, the efficacy and mechanisms of action of this flavonoid agent are still undergoing study. In order to elucidate whether luteolin exhibits an anticancer effect in cervical cancer cells, HeLa cells were incubated with luteolin and apoptosis was assessed by observing nuclear morphological changes, and performing Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Cell cycle analysis, western blotting, RT-PCR and mitochondrial membrane potential measurements were also carried out. Luteolin showed a significant dose-dependent cytotoxic effect only in human papillomavirus (HPV)-positive cervical cancer cells, when compared to its effect on HPV-negative cervical cancer C33A cells. Expression levels of human papilloma virus E6 and E7 oncogenes were suppressed, those of related factors pRb and p53 were recovered and E2F5 was increased by luteolin treatment. Furthermore, luteolin enhanced the expression of death receptors and death receptor downstream factors such as Fas/FasL, DR5/TRAIL and FADD in HeLa cells, and activated caspase cascades. In particular, luteolin enhanced the activity of caspase-3 and -8 in a dose-dependent manner. Activation of caspase-3 induced caspase-8 activity and vice versa. Luteolin also induced mitochondrial membrane potential collapse and cytochrome c release, and inhibited Bcl-2 and Bcl-xL expression. In conclusion, luteolin exerts anticarcinogenic activity through inhibition of E6 and E7 expression and cross-activation of caspase-3 and -8. Taken together, these results suggest that luteolin induces inactivation of HPV-18 oncogene expression and apoptosis by activating the intrinsic and extrinsic pathways. PMID:24789165

Ham, Sunyoung; Kim, Ki Hong; Kwon, Tae Ho; Bak, Yesol; Lee, Dong Hun; Song, Yong Seok; Park, Su-Ho; Park, Yun Sun; Kim, Man Sub; Kang, Jeong Woo; Hong, Jin Tae; Yoon, Do-Young

2014-06-01

66

Andrographolide downregulates the v-Src and Bcr-Abl oncoproteins and induces Hsp90 cleavage in the ROS-dependent suppression of cancer malignancy.  

PubMed

Andrographolide is a diterpenoid compound isolated from Andrographis paniculata that exhibits anticancer activity. We previously reported that andrographolide suppressed v-Src-mediated cellular transformation by promoting the degradation of Src. In the present study, we demonstrated the involvement of Hsp90 in the andrographolide-mediated inhibition of Src oncogenic activity. Using a proteomics approach, a cleavage fragment of Hsp90? was identified in andrographolide-treated cells. The concentration- and time-dependent induction of Hsp90 cleavage that accompanied the reduction in Src was validated in RK3E cells transformed with either v-Src or a human truncated c-Src variant and treated with andrographolide. In cancer cells, the induction of Hsp90 cleavage by andrographolide and its structural derivatives correlated well with decreased Src levels, the suppression of transformation, and the induction of apoptosis. Moreover, the andrographolide-induced Hsp90 cleavage, Src degradation, inhibition of transformation, and induction of apoptosis were abolished by a ROS inhibitor, N-acetyl-cysteine. Notably, Hsp90 cleavage, decreased levels of Bcr-Abl (another known Hsp90 client protein), and the induction of apoptosis were also observed in human K562 leukemia cells treated with andrographolide or its active derivatives. Together, we demonstrated a novel mechanism by which andrographolide suppressed cancer malignancy that involved inhibiting Hsp90 function and reducing the levels of Hsp90 client proteins. Our results broaden the molecular basis of andrographolide-mediated anticancer activity. PMID:24161787

Liu, Sheng-Hung; Lin, Chao-Hsiung; Liang, Fong-Ping; Chen, Pei-Fen; Kuo, Cheng-Deng; Alam, Mohd Mujahid; Maiti, Barnali; Hung, Shih-Kai; Chi, Chin-Wen; Sun, Chung-Ming; Fu, Shu-Ling

2014-01-15

67

Molecular Targeting of the Oncoprotein PLK1 in Pediatric Acute Myeloid Leukemia: RO3280, a Novel PLK1 Inhibitor, Induces Apoptosis in Leukemia Cells  

PubMed Central

Polo-like kinase 1 (PLK1) is highly expressed in many cancers and therefore a biomarker of transformation and potential target for the development of cancer-specific small molecule drugs. RO3280 was recently identified as a novel PLK1 inhibitor; however its therapeutic effects in leukemia treatment are still unknown. We found that the PLK1 protein was highly expressed in leukemia cell lines as well as 73.3% (11/15) of pediatric acute myeloid leukemia (AML) samples. PLK1 mRNA expression was significantly higher in AML samples compared with control samples (82.95 ± 110.28 vs. 6.36 ± 6.35; p < 0.001). Kaplan-Meier survival analysis revealed that shorter survival time correlated with high tumor PLK1 expression (p = 0.002). The 50% inhibitory concentration (IC50) of RO3280 for acute leukemia cells was between 74 and 797 nM. The IC50 of RO3280 in primary acute lymphocytic leukemia (ALL) and AML cells was between 35.49 and 110.76 nM and 52.80 and 147.50 nM, respectively. RO3280 induced apoptosis and cell cycle disorder in leukemia cells. RO3280 treatment regulated several apoptosis-associated genes. The regulation of DCC, CDKN1A, BTK, and SOCS2 was verified by western blot. These results provide insights into the potential use of RO3280 for AML therapy; however, the underlying mechanisms remain to be determined. PMID:25574601

Wang, Na-Na; Li, Zhi-Heng; Zhao, He; Tao, Yan-Fang; Xu, Li-Xiao; Lu, Jun; Cao, Lan; Du, Xiao-Juan; Sun, Li-Chao; Zhao, Wen-Li; Xiao, Pei-Fang; Fang, Fang; Su, Guang-Hao; Li, Yan-Hong; Li, Gang; Li, Yi-Ping; Xu, Yun-Yun; Zhou, Hui-Ting; Wu, Yi; Jin, Mei-Fang; Liu, Lin; Ni, Jian; Wang, Jian; Hu, Shao-Yan; Zhu, Xue-Ming; Feng, Xing; Pan, Jian

2015-01-01

68

Molecular targeting of the oncoprotein PLK1 in pediatric acute myeloid leukemia: RO3280, a novel PLK1 inhibitor, induces apoptosis in leukemia cells.  

PubMed

Polo-like kinase 1 (PLK1) is highly expressed in many cancers and therefore a biomarker of transformation and potential target for the development of cancer-specific small molecule drugs. RO3280 was recently identified as a novel PLK1 inhibitor; however its therapeutic effects in leukemia treatment are still unknown. We found that the PLK1 protein was highly expressed in leukemia cell lines as well as 73.3% (11/15) of pediatric acute myeloid leukemia (AML) samples. PLK1 mRNA expression was significantly higher in AML samples compared with control samples (82.95 ± 110.28 vs. 6.36 ± 6.35; p < 0.001). Kaplan-Meier survival analysis revealed that shorter survival time correlated with high tumor PLK1 expression (p = 0.002). The 50% inhibitory concentration (IC50) of RO3280 for acute leukemia cells was between 74 and 797 nM. The IC50 of RO3280 in primary acute lymphocytic leukemia (ALL) and AML cells was between 35.49 and 110.76 nM and 52.80 and 147.50 nM, respectively. RO3280 induced apoptosis and cell cycle disorder in leukemia cells. RO3280 treatment regulated several apoptosis-associated genes. The regulation of DCC, CDKN1A, BTK, and SOCS2 was verified by western blot. These results provide insights into the potential use of RO3280 for AML therapy; however, the underlying mechanisms remain to be determined. PMID:25574601

Wang, Na-Na; Li, Zhi-Heng; Zhao, He; Tao, Yan-Fang; Xu, Li-Xiao; Lu, Jun; Cao, Lan; Du, Xiao-Juan; Sun, Li-Chao; Zhao, Wen-Li; Xiao, Pei-Fang; Fang, Fang; Su, Guang-Hao; Li, Yan-Hong; Li, Gang; Li, Yi-Ping; Xu, Yun-Yun; Zhou, Hui-Ting; Wu, Yi; Jin, Mei-Fang; Liu, Lin; Ni, Jian; Wang, Jian; Hu, Shao-Yan; Zhu, Xue-Ming; Feng, Xing; Pan, Jian

2015-01-01

69

int. j. radiat. biol 2001, vol. 77, no. 1, 31 40 Oncoprotein expression in human breast epithelial cells  

E-print Network

and tumorigenic human breast epithelial cells Other changes may confer genetic instability, induced by high-LET a have both its genesis and human breast epithelial cells induced by high-LET radiation. In cell growthint. j. radiat. biol 2001, vol. 77, no. 1, 31± 40 Oncoprotein expression in human breast epithelial

70

Activation of Wnt signaling pathway by human papillomavirus E6 and E7 oncogenes in HPV16-positive oropharyngeal squamous carcinoma cells.  

PubMed

We sought to determine the role of human papillomavirus (HPV) E6 and E7 oncogenes in nuclear beta-catenin accumulation, a hallmark of activated canonical Wnt signaling pathway. We used HPV16-positive oropharyngeal cancer cell lines 147T and 090, HPV-negative cell line 040T, and cervical cell lines SiHa (bearing integrated HPV16) and HeLa (bearing integrated HPV18) to measure the cytoplasmic and nuclear beta-catenin levels and the beta-catenin/Tcf transcriptional activity before and after E6/E7 gene silencing. Repression of HPV E6 and E7 genes induced a substantial reduction in nuclear beta-catenin levels. Luciferase assay showed that transcriptional activation of Tcf promoter by beta-catenin was lower after silencing. The protein levels of beta-catenin are tightly regulated by the ubiquitin/proteasome system. We therefore performed expression analysis of regulators of beta-catenin degradation and nuclear transport and showed that seven in absentia homologue (Siah-1) mRNA and protein levels were substantially upregulated after E6/E7 repression. Siah-1 protein promotes the degradation of beta-catenin through the ubiquitin/proteasome system. To determine whether Siah-1 is important for the proteasomal degradation of beta-catenin in HPV16-positive oropharyngeal cancer cells, we introduced a Siah-1 expression vector into 147T and 090 cells and found substantial reduction of endogenous beta-catenin in these cells. Thus, E6 and E7 are involved in beta-catenin nuclear accumulation and activation of Wnt signaling in HPV-induced cancers. In addition, we show the significance of the endogenous Siah-1-dependent ubiquitin/proteasome pathway for beta-catenin degradation and its regulation by E6/E7 viral oncoproteins in HPV16-positive oropharyngeal cancer cells. PMID:20215420

Rampias, Theodore; Boutati, Eleni; Pectasides, Eirini; Sasaki, Clarence; Kountourakis, Panteleimon; Weinberger, Paul; Psyrri, Amanda

2010-03-01

71

E6 and E7 from human papillomavirus type 16 cooperate to target the PDZ protein Na/H exchange regulatory factor 1.  

PubMed

Previous studies have shown that the PDZ-binding motif of the E6 oncoprotein from the mucosal high-risk (HR) human papillomavirus (HPV) types plays a key role in HPV-mediated cellular transformation in in vitro and in vivo experimental models. HR HPV E6 oncoproteins have the ability to efficiently degrade members of the PDZ motif-containing membrane-associated guanylate kinase (MAGUK) family; however, it is possible that other PDZ proteins are also targeted by E6. Here, we describe a novel interaction of HPV type 16 (HPV16) E6 with a PDZ protein, Na(+)/H(+) exchange regulatory factor 1 (NHERF-1), which is involved in a number of cellular processes, including signaling and transformation. HPV16 E6 associates with and promotes the degradation of NHERF-1, and this property is dependent on the C-terminal PDZ-binding motif of E6. Interestingly, HPV16 E7, via the activation of the cyclin-dependent kinase complexes, promoted the accumulation of a phosphorylated form of NHERF-1, which is preferentially targeted by E6. Thus, both oncoproteins appear to cooperate in targeting NHERF-1. Notably, HPV18 E6 is not able to induce NHERF-1 degradation, indicating that this property is not shared with E6 from all HR HPV types. Downregulation of NHERF-1 protein levels was also observed in HPV16-positive cervical cancer-derived cell lines, such as SiHa and CaSki, as well as HPV16-positive cervical intraepithelial neoplasia (CIN). Finally, our data show that HPV16-mediated NHERF-1 degradation correlates with the activation of the phosphatidylinositol-3'-OH kinase (PI3K)/AKT signaling pathway, which is known to play a key role in carcinogenesis. PMID:21680517

Accardi, Rosita; Rubino, Rosa; Scalise, Mariafrancesca; Gheit, Tarik; Shahzad, Naveed; Thomas, Miranda; Banks, Lawrence; Indiveri, Cesare; Sylla, Bakary S; Cardone, Rosa A; Reshkin, Stephan J; Tommasino, Massimo

2011-08-01

72

E6 and E7 from Human Papillomavirus Type 16 Cooperate To Target the PDZ Protein Na/H Exchange Regulatory Factor 1 ?  

PubMed Central

Previous studies have shown that the PDZ-binding motif of the E6 oncoprotein from the mucosal high-risk (HR) human papillomavirus (HPV) types plays a key role in HPV-mediated cellular transformation in in vitro and in vivo experimental models. HR HPV E6 oncoproteins have the ability to efficiently degrade members of the PDZ motif-containing membrane-associated guanylate kinase (MAGUK) family; however, it is possible that other PDZ proteins are also targeted by E6. Here, we describe a novel interaction of HPV type 16 (HPV16) E6 with a PDZ protein, Na+/H+ exchange regulatory factor 1 (NHERF-1), which is involved in a number of cellular processes, including signaling and transformation. HPV16 E6 associates with and promotes the degradation of NHERF-1, and this property is dependent on the C-terminal PDZ-binding motif of E6. Interestingly, HPV16 E7, via the activation of the cyclin-dependent kinase complexes, promoted the accumulation of a phosphorylated form of NHERF-1, which is preferentially targeted by E6. Thus, both oncoproteins appear to cooperate in targeting NHERF-1. Notably, HPV18 E6 is not able to induce NHERF-1 degradation, indicating that this property is not shared with E6 from all HR HPV types. Downregulation of NHERF-1 protein levels was also observed in HPV16-positive cervical cancer-derived cell lines, such as SiHa and CaSki, as well as HPV16-positive cervical intraepithelial neoplasia (CIN). Finally, our data show that HPV16-mediated NHERF-1 degradation correlates with the activation of the phosphatidylinositol-3?-OH kinase (PI3K)/AKT signaling pathway, which is known to play a key role in carcinogenesis. PMID:21680517

Accardi, Rosita; Rubino, Rosa; Scalise, Mariafrancesca; Gheit, Tarik; Shahzad, Naveed; Thomas, Miranda; Banks, Lawrence; Indiveri, Cesare; Sylla, Bakary S.; Cardone, Rosa A.; Reshkin, Stephan J.; Tommasino, Massimo

2011-01-01

73

The biological properties of E6 and E7 oncoproteins from human papillomaviruses  

Microsoft Academic Search

More than 100 different human papillomavirus (HPV) types have been isolated so far, and they can be sub-grouped in cutaneous\\u000a or mucosal according to their ability to infect the skin or the mucosa of the genital or upper-respiratory tracts. A sub-group\\u000a of human mucosal HPVs, referred to as high-risk HPV types, is responsible for approximately 5% of all human cancers,

Raffaella Ghittoni; Rosita Accardi; Uzma Hasan; Tarik Gheit; Bakary Sylla; Massimo Tommasino

2010-01-01

74

E6 and E7 fusion immunoglobulin from human papilloma virus 16 induces dendritic cell maturation and antigen specific activation of T helper 1 response  

Microsoft Academic Search

Human papilloma virus (HPV) 16 causes cervical cancer. Induction of oncogenesis by HPV 16 is primarily dependent on the function\\u000a of E6 and E7 proteins, which inactivate the function of p53 and pRB, respectively. Thus, blocking the activity of the E6 and\\u000a E7 proteins from HPV 16 is critical to inhibiting oncogenesis during infection. We have expressed and purified soluble

Sang-Hoon Kim; Yu Jin Hur; Suk Jun Lee; Sang Joon Kim; Chung-Gyu Park; Yu-Koung Oh; Woon-Won Jung; Jong Bok Seo; Myung Hee Nam; Inho Choi; Taehoon Chun

2011-01-01

75

Episomal expression of truncated listeriolysin O in LmddA-LLO-E7 vaccine enhances antitumor efficacy by preferentially inducing expansions of CD4+FoxP3- and CD8+ T cells.  

PubMed

Studies have shown that Listeria monocytogenes (Lm)-based vaccine expressing a fusion protein comprising truncated listeriolysin O (LLO) and human papilloma virus (HPV) E7 protein (Lm-LLO-E7) induces a decrease in regulatory T cells (Treg) and complete regression of established, transplanted HPV-TC-1 tumors in mice. However, how the Lm-based vaccine causes a decrease in Tregs remains unclear. Using a highly attenuated Lm dal dat ?actA strain (LmddA)-based vaccine, we report here that the vector LmddA was sufficient to induce a decrease in the proportion of Tregs by preferentially expanding CD4(+)FoxP3(-) T cells and CD8(+) T cells by a mechanism dependent on and directly mediated by LLO. Episomal expression of a nonhemolytic truncated LLO in Lm (LmddA-LLO) significantly augmented the expansion, thus further decreasing Treg frequency. Although adoptive transfer of Tregs compromised the antitumor efficacy of the LmddA-LLO-E7 vaccine, a combination of LmddA-LLO and an Lm-based vaccine expressing E7 protein (Lm-E7) induced complete regression against established TC-1 tumors. An engineered LLO-minus Lm expressing perfringolysin O (PFO) that enables the recombinant bacteria to exit from the phagolysosome without LLO confirmed that the adjuvant effect was dependent on LLO. These results suggest that LLO may serve as a promising adjuvant by preferentially inducing the expansions of CD4(+)FoxP3(-) T cells and CD8(+) T cells, thus reducing the ratio of Tregs to CD4(+)FoxP3(-) T cells and to CD8(+) T cells favoring immune responses to eradicate tumor. PMID:24872025

Chen, Zhisong; Ozbun, Laurent; Chong, Namju; Wallecha, Anu; Berzofsky, Jay A; Khleif, Samir N

2014-09-01

76

Effect of high-risk human papillomavirus oncoproteins on p53R2 gene expression after DNA damage.  

PubMed

The p53R2 protein is a p53-inducible small subunit of ribonucleotide reductase. It plays a crucial role in p53-dependent cellular response to DNA damage and oxidative stress by providing deoxyribonucleotides (dNTPs) to the DNA repair machinery and by scavenging reactive oxygen species (ROS). To investigate the effects of high-risk human papillomavirus (HPV) oncoproteins on p53R2 expression after DNA damage, we analyzed the p53R2 protein levels in human cells ectopically expressing the HPV-16 E6 and E7 genes, and in the HPV-positive cancer cell lines SiHa, CaSki and HeLa, exposed to adriamycin or to H(2)O(2). We found that in normal cells, p53R2 expression is efficiently induced by both H(2)O(2) and adriamycin, supporting the role of p53R2 in cellular response to oxidative stress. Ectopic expression of E6 impaired p53 and p53R2 induction after DNA damage in human fibroblasts. Moreover, SiHa, CaSki and HeLa cells were unresponsive to H(2)O(2) exposure, and adriamycin induced p53R2 levels only in SiHa cells. Our results imply that high-risk HPV infection may suppress the p53R2-dependent dNTPs supply to the DNA repair system and the ROS scavenging activity; they also suggest that an altered p53R2 response to genotoxins and to oxidative stress may contribute to HPV-induced genetic instability and carcinogenesis. PMID:16872707

Lembo, David; Donalisio, Manuela; Cornaglia, Maura; Azzimonti, Barbara; Demurtas, Anna; Landolfo, Santo

2006-12-01

77

Ethyl 1,8-naphthyridone-3-carboxylates downregulate human papillomavirus-16 E6 and E7 oncogene expression.  

PubMed

Strong epidemiological and molecular data associate cervical cancer (CC) with high-risk human papillomavirus (HPV) infections. The carcinogenic mechanism depends mainly on the expression of E6 and E7 oncoproteins encoded by the viral genome. Using a cell-based high-throughput assay, an in-house library of compounds was screened identifying the 1,8-naphthyridone 1 that efficiently inhibited the transcription driven by the long control region of the HPV genome. A series of analogues were then synthesized, obtaining more potent derivatives able to downregulate E6 and E7 transcripts in HPV-16-positive CC CaSki cells. An unusual structural insight emerged for the C-3 position of the 1,8-naphthyridone core, where the ethyl carboxylate esters, but not the carboxylic acids, are responsible for the activity. In vitro uptake studies showed that the 3-ethyl carboxylates do not act as prodrugs. The 1,8-naphthyridones emerged as valid starting points for the development of innovative agents potentially useful for the treatment of HPV-induced CC. PMID:24905115

Donalisio, Manuela; Massari, Serena; Argenziano, Monica; Manfroni, Giuseppe; Cagno, Valeria; Civra, Andrea; Sabatini, Stefano; Cecchetti, Violetta; Loregian, Arianna; Cavalli, Roberta; Lembo, David; Tabarrini, Oriana

2014-07-10

78

miR-24 and miR-205 expression is dependent on HPV onco-protein expression in keratinocytes?  

PubMed Central

A screen of microRNA (miRNA) expression following differentiation in human foreskin keratinocytes (HFKs) identified changes in several miRNAs, including miR-24 and miR-205. We investigated how expression of Human Papilloma Virus Type-16 (HPV16) onco-proteins E6 and E7 affected expression of miR-24 and miR-205 during proliferation and differentiation of HFKs. We show that the induction of both miR-24 and miR-205 observed during differentiation of HFKs is lost in HFKs expressing E6 and E7. We demonstrate that the effect on miR-205 is due to E7 activity, as miR-205 expression is dependent on pRb expression. Finally, we provide evidence that miR-24 effects in the cell may be due to targeting of cyclin dependent kinase inhibitor p27. In summary, these results indicate that expression of both miR-24 and miR-205 are impacted by E6 and/or E7 expression, which may be one mechanism by which HPV onco-proteins can disrupt the balance between proliferation and differentiation in keratinocytes. PMID:24314651

McKenna, Declan J.; Patel, Daksha; McCance, Dennis J.

2014-01-01

79

Histone demethylase JARID1B promotes cell proliferation but is downregulated by N-Myc oncoprotein.  

PubMed

Myc oncoproteins induce tumor initiation and promote tumor progression by modulating gene transcription. We have previously shown that N-Myc represses gene transcription by recruiting histone deacetylases to Sp1-binding site-enriched regions of target gene promoters. The histone demethylase JARID1B plays a dual role in cancer. In the present study, we examined published microarray gene expression datasets and found that JARID1B was commonly repressed by Myc oncoproteins and histone deacetylases in cancer cell lines of various organ origins. Chromatin immunoprecipitation assays demonstrated that N-Myc repressed JARID1B expression by direct binding to the Sp1-binding site-enriched region of the JARID1B gene promoter, and cell proliferation assays showed that transcriptional repression of JARID1B reduced neuroblastoma cell proliferation. Our findings suggest that Myc-mediated transcriptional repression of JARID1B counterintuitively inhibits Myc-regulated cell proliferation and potentially tumorigenesis. PMID:24481781

Zhang, Lihong; Sokolowski, Nicolas; Atmadibrata, Bernard; Liu, Tao

2014-04-01

80

HPV16E7-Specific siRNA Inhibits Cell Proliferation in CaSki Cells.  

PubMed

High-risk human papilloma virus (HPV) infection is the main cause for the genesis of cervical carcinomas. After infection, E6 and E7 genes of HPV were integrated to the genome of the cervical epithelium. Continued expression of the transforming oncoproteins E6 and E7 not only drives the neoplastic progression in cervical epithelium, but also plays an important role in maintaining the malignant phenotype of cervical cancer cells. The aim of this study is to explore the effects of liposomal transfection of HPV16E7 siRNA on the proliferation of cervical carcinoma cell line CaSki. The siRNA interfering HPV16E7 gene was synthesized and transfected into CaSki cells by liposome to observe the cell morphology changes under microscope. The cell proliferation index was detected by flow cytometry; HPV16E7 mRNA expression was determined by RT-PCR and its protein level was determined by Western blot. After transfection of the CaSki cell by siRNA, cell proliferation was inhibited significantly, and the expression of HPV16E7 mRNA and protein level of HPV16E7 decreased. HPV16E7 siRNA is able to inhibit growth of CaSki cells. HPV16E7 might become a new target for genetic therapy of cervical carcinoma. PMID:25548001

Li, Jun-Guo; Li, Li; Zhang, Shui-Wen; Wei, Xiaoguang

2015-03-01

81

HPV E7 contributes to the telomerase activity of immortalized and tumorigenic cells and augments E6-induced hTERT promoter function  

Microsoft Academic Search

The E6 and E7 proteins of high-risk HPVs are both required for the immortalization of primary human keratinocytes and the maintenance of the malignant phenotype of HPV-positive cancer cell lines. Our previous studies have shown that E6 protein binds Myc protein and that both E6 and Myc associate with and cooperatively activate the hTERT promoter, thereby increasing cellular telomerase activity.

Xuefeng Liu; Jeffrey Roberts; Aleksandra Dakic; Yiyu Zhang; Richard Schlegel

2008-01-01

82

The E6 Oncoproteins of High-Risk Papillomaviruses Bind to a Novel Putative GAP Protein, E6TP1, and Target It for Degradation  

Microsoft Academic Search

The high-risk human papillomaviruses (HPVs) are associated with carcinomas of the cervix and other genital tumors. Previous studies have identified two viral oncoproteins, E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high-risk HPV E6 protein to immortalize human mam- mary epithelial cells (MECs) has provided a single-gene model to study the mechanisms of

QINGSHEN GAO; SEETHA SRINIVASAN; SARAH N. BOYER; DAVID E. WAZER; VIMLA BAND

1999-01-01

83

The epithelial-mesenchymal transition induced by keratinocyte growth conditions is overcome by E6 and E7 from HPV16, but not HPV8 and HPV38: Characterization of global transcription profiles  

SciTech Connect

The aim of this study was to evaluate the growth properties of primary human keratinocytes expressing E6 and E7 proteins, which are from either the beta- or alpha-genotypes, under different culture conditions. We demonstrated that keratinocytes expressing E6 and E7, from both HPV8 and 38, irreversibly underwent the epithelial-mesenchymal transition (EMT) when grown on plastic with FAD medium (F12/DMEM/5%FBS). Expression of E6/E7 from HPV16 was capable of fully overcoming the FAD-induced EMT. Immortalization was only observed in HPV16-transduced cell lines, while the more proliferating phenotype of both KerHPV8 and 38 was mainly related to FAD-induced EMT. Microarray analysis of exponentially growing cells identified 146 cellular genes that were differentially regulated in HPV16 compared to HPV8- and 38-transduced cells. A large accumulation of transcripts associated with epidermal development and differentiation was observed in HPV16-transduced cells, whereas transcripts of genes involved in the extracellular matrix, multicellular organismal processes, and inflammatory response were affected in HPV8 and 38-transduced cells.

Azzimonti, Barbara; Dell'Oste, Valentina; Borgogna, Cinzia; Mondini, Michele [Department of Clinical and Experimental Medicine, Medical School of Novara, via Solaroli 17, 28100 Novara (Italy); Gugliesi, Francesca [Department of Public Health and Microbiology, Medical School of Turin, via Santena 9, 10126 Torino (Italy); De Andrea, Marco [Department of Clinical and Experimental Medicine, Medical School of Novara, via Solaroli 17, 28100 Novara (Italy); Department of Public Health and Microbiology, Medical School of Turin, via Santena 9, 10126 Torino (Italy); Chiorino, Giovanna; Scatolini, Maria; Ghimenti, Chiara [Cancer Genomics Lab Fondo Edo Tempia, via Malta 3, 13900 Biella (Italy); Landolfo, Santo [Department of Public Health and Microbiology, Medical School of Turin, via Santena 9, 10126 Torino (Italy); Gariglio, Marisa, E-mail: gariglio@med.unipmn.i [Department of Clinical and Experimental Medicine, Medical School of Novara, via Solaroli 17, 28100 Novara (Italy)

2009-06-05

84

Interferon-? induced microRNA-129-5p down-regulates HPV-18 E6 and E7 viral gene expression by targeting SP1 in cervical cancer cells.  

PubMed

Infection by human papillomavirus (HPV) can cause cervical intraepithelial neoplasia (CIN) and cancer. Down-regulation of E6 and E7 expression may be responsible for the positive clinical outcomes observed with IFN treatment, but the molecular basis has not been well determined. As miRNAs play an important role in HPV induced cervical carcinogenesis, we hypothesize that IFN-? can regulate the expressions of specific miRNAs in cervical cancer cells, and that these miRNAs can mediate E6 and E7 expression, thus modulate their oncogenic potential. In this study, we found that miR-129-5p to be a candidate IFN-? inducible miRNA. MiR-129-5p levels gradually decrease with the development of cervical intraepithelial lesions. Manipulation of miR-129-5p expression in Hela cells modulates HPV-18 E6 and E7 viral gene expression. Exogenous miR-129-5p inhibits cell proliferation in Hela cells, promotes apoptosis and blocks cell cycle progression in Hela cells. SP1 is a direct target of miR-129-5p in Hela cells. This study is the first report of a cellular miRNA with anti-HPV activity and provides new insights into regulatory mechanisms between the HPV and the IFN system in host cells at the miRNA level. PMID:24358111

Zhang, Jiarong; Li, Shuangdi; Yan, Qin; Chen, Xiaoyue; Yang, Yixia; Liu, Xuelian; Wan, Xiaoping

2013-01-01

85

Human papilloma virus (HPV) E7-mediated attenuation of retinoblastoma (Rb) induces hPygopus2 expression via Elf-1 in cervical cancer.  

PubMed

The human papillomavirus (HPV) is the etiologic agent of cervical cancer. In this study, we provide evidence for the human Pygopus (hPygo)2 gene as a cellular biomarker for HPV-related disease. In a tumor microarray of cervical cancer progression, hPygo2 levels were greater in high-grade lesions and squamous cell carcinomas than in normal epithelia. Similarly, hPygo2 mRNA and protein levels were greater in HPV-positive cervical cancer cells relative to uninfected primary cells. RNA interference (RNAi)-mediated depletion of HPV-E7 increased whereas E74-like factor (Elf)-1 RNAi decreased association of Retinoblastoma (Rb) tumor suppressor with the hPygo2 promoter in cervical cancer cell lines. Transfection of dominant-active Rb inhibited Elf-1-dependent activation of hPygo2, whereas Elf-1 itself increased hPygo2 expression. Chromatin immunoprecipitation assays showed that Rb repressed hPygo2 by inhibiting Elf-1 at the Ets-binding site in the hPygo2 promoter. These results suggested that abrogation of Rb by E7 resulted in derepression of Elf-1, which in turn stimulated expression of hPygo2. Thus, initiation of hPygo2 expression by Elf-1 was required for proliferation of cervical cancer cells and its expression therefore may act as a surrogate marker for dysplasia. PMID:23284001

Tzenov, Youlian R; Andrews, Phillip G; Voisey, Kim; Popadiuk, Paul; Xiong, Jieying; Popadiuk, Catherine; Kao, Kenneth R

2013-01-01

86

Karyopherin {beta}3: A new cellular target for the HPV-16 E5 oncoprotein  

SciTech Connect

Epidemiological and experimental studies have shown that high-risk human papillomaviruses (HPVs) are the causative agents of cervical cancer worldwide, and that HPV-16 is associated with more than half of these cases. In addition to the well-characterized E6 and E7 oncoproteins of HPV-16, recent evidence increasingly has implicated the HPV-16 E5 protein (16E5) as an important mediator of oncogenic transformation. Since 16E5 has no known intrinsic enzymatic activity, its effects on infected cells are most likely mediated by interactions with various cellular proteins and/or its documented association with lipid rafts. In the present study, we describe a new cellular target that binds to 16E5 in COS cells and in stable human ectocervical cell lines. This target is karyopherin {beta}3, a member of the nuclear import receptor family with critical roles in the nuclear import of ribosomal proteins and in the secretory pathway.

Krawczyk, Ewa [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States); Hanover, John A. [Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Schlegel, Richard [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States); Suprynowicz, Frank A. [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States)], E-mail: suprynfa@georgetown.edu

2008-07-11

87

Immunization with an HPV-16 L1-based chimeric virus-like particle containing HPV-16 E6 and E7 epitopes elicits long-lasting prophylactic and therapeutic efficacy in an HPV-16 tumor mice model.  

PubMed

HPV L1-based virus-like particles vaccines (VLPs) efficiently induce temporary prophylactic activity through the induction of neutralizing antibodies; however, VLPs that can provide prophylactic as well as therapeutic properties for longer periods of time are needed. For this purpose, we generated a novel HPV 16 L1-based chimeric virus-like particle (cVLP) produced in plants that contains a string of T-cell epitopes from HPV 16 E6 and E7 fused to its C-terminus. In the present study, we analyzed the persistence of specific IgG antibodies with neutralizing activity induced by immunization with these cVLPs, as well as their therapeutic potential in a tumor model of C57BL/6 mice. We observed that these cVLPs induced persistent IgG antibodies for over 12 months, with reactivity and neutralizing activity for VLPs composed of only the HPV-16 L1 protein. Efficient protection for long periods of time and inhibition of tumor growth induced by TC-1 tumor cells expressing HPV-16 E6/E7 oncoproteins, as well as significant tumor reduction (57 %), were observed in mice immunized with these cVLPs. Finally, we discuss the possibility that chimeric particles of the type described in this work may be the basis for developing HPV prophylactic and therapeutic vaccines with high efficacy. PMID:23990055

Monroy-García, Alberto; Gómez-Lim, Miguel Angel; Weiss-Steider, Benny; Hernández-Montes, Jorge; Huerta-Yepez, Sara; Rangel-Santiago, Jesús F; Santiago-Osorio, Edelmiro; Mora García, María de Lourdes

2014-02-01

88

Effect of high-risk human papillomavirus oncoproteins on p53R2 gene expression after DNA damage  

Microsoft Academic Search

The p53R2 protein is a p53-inducible small subunit of ribonucleotide reductase. It plays a crucial role in p53-dependent cellular response to DNA damage and oxidative stress by providing deoxyribonucleotides (dNTPs) to the DNA repair machinery and by scavenging reactive oxygen species (ROS). To investigate the effects of high-risk human papillomavirus (HPV) oncoproteins on p53R2 expression after DNA damage, we analyzed

David Lembo; Manuela Donalisio; Maura Cornaglia; Barbara Azzimonti; Anna Demurtas; Santo Landolfo

2006-01-01

89

High-risk human papillomavirus E6 oncoproteins interact with 14-3-3? in a PDZ binding motif-dependent manner.  

PubMed

Cervical cancer develops through the combined activities of the human papillomavirus (HPV) E6 and E7 oncoproteins. A defining characteristic of E6 oncoproteins derived from cancer-causing HPV types is the presence of a PDZ binding motif (PBM) at the extreme carboxy terminus of the protein which is absent from E6 proteins derived from the so-called low-risk HPV types. Within this PBM is also a protein kinase A (PKA) phospho-acceptor site, which is thought to negatively regulate the association of E6 with its PDZ domain-containing substrates. We can now show that phosphorylation of E6 by PKA and/or AKT confers the ability to interact with 14-3-3?. The interaction is direct and specific for the high-risk HPV E6 oncoproteins, although there are significant differences in the efficiencies with which HPV-16, HPV-18, and HPV-31 E6 oncoproteins can associate with 14-3-3?; this correlates directly with their respective susceptibilities to phosphorylation by PKA and/or AKT. We demonstrate here that the interaction between E6 and 14-3-3? also requires integrity of the E6 PBM, and downregulation of 14-3-3? results in a marked reduction in the levels of HPV-18 E6 expression in HeLa cells. Using phospho-specific anti-E6 antibodies, we also demonstrate significant levels of E6 phosphorylation in vivo. These studies redefine the potential relevance of the E6 PBM in the development of cervical cancer, suggesting that interaction with 14-3-3?, as well as the more well-established interactions with PDZ domain-containing substrates, is likely to be responsible for the biological activities attributed to this region of the high-risk HPV E6 oncoproteins. PMID:23175360

Boon, Siaw Shi; Banks, Lawrence

2013-02-01

90

High-Risk Human Papillomavirus E6 Oncoproteins Interact with 14-3-3? in a PDZ Binding Motif-Dependent Manner  

PubMed Central

Cervical cancer develops through the combined activities of the human papillomavirus (HPV) E6 and E7 oncoproteins. A defining characteristic of E6 oncoproteins derived from cancer-causing HPV types is the presence of a PDZ binding motif (PBM) at the extreme carboxy terminus of the protein which is absent from E6 proteins derived from the so-called low-risk HPV types. Within this PBM is also a protein kinase A (PKA) phospho-acceptor site, which is thought to negatively regulate the association of E6 with its PDZ domain-containing substrates. We can now show that phosphorylation of E6 by PKA and/or AKT confers the ability to interact with 14-3-3?. The interaction is direct and specific for the high-risk HPV E6 oncoproteins, although there are significant differences in the efficiencies with which HPV-16, HPV-18, and HPV-31 E6 oncoproteins can associate with 14-3-3?; this correlates directly with their respective susceptibilities to phosphorylation by PKA and/or AKT. We demonstrate here that the interaction between E6 and 14-3-3? also requires integrity of the E6 PBM, and downregulation of 14-3-3? results in a marked reduction in the levels of HPV-18 E6 expression in HeLa cells. Using phospho-specific anti-E6 antibodies, we also demonstrate significant levels of E6 phosphorylation in vivo. These studies redefine the potential relevance of the E6 PBM in the development of cervical cancer, suggesting that interaction with 14-3-3?, as well as the more well-established interactions with PDZ domain-containing substrates, is likely to be responsible for the biological activities attributed to this region of the high-risk HPV E6 oncoproteins. PMID:23175360

Boon, Siaw Shi

2013-01-01

91

Analysis of human papillomavirus E7 protein status in C-33A cervical cancer cells.  

PubMed

High-risk human papillomaviruses (HPV) are the main etiologic factor for the development of cervical cancer. Infections by these viruses have been detected in virtually all cervical cancers. C-33A is one of the rare cervical cancer derived cell lines considered as HPV-negative. Employing monoclonal antibodies raised against a conformational epitope of the HPV-16 E7 oncoprotein, we present evidence suggesting that E7-positive cells can be sporadically and transiently detected in C-33A cell cultures. Immunoblotting with affinity-purified rabbit polyclonal anti-HPV 16 E7 antisera and q-RT-PCR analysis suggest that these cells do probably not express HPV-16 E7. Moreover, we show that the HPV E7 protein level differs considerably between individual cells in cultures of several established cervical cancer cell lines. Our data suggest that expression of the E7 protein is variable in established cervical cancer cell lines including C-33A cells. PMID:25326774

Kaiser, Andreas; Jenewein, Brigitte; Pircher, Haymo; Rostek, Ursula; Jansen-Dürr, Pidder; Zwerschke, Werner

2015-02-01

92

Type-specific interaction between human papillomavirus type 58 E2 protein and E7 protein inhibits E7-mediated oncogenicity.  

PubMed

Human papillomavirus type 58 (HPV-58) is a very common HPV type in eastern Asia. Little is known about its biology and tumorigenesis. In this study, HPV-58 E2 protein (58E2) was found to interact with E7 protein (58E7), and the hinge domain of 58E2 was shown to be responsible for binding to the 58E7 protein. Interestingly, the E2-E7 interaction appears to be HPV type-specific, as we found that the HPV-16 E2 could not bind to the 58E7 protein, and neither did 58E2 interact with HPV-16 E7. The biological consequence(s) of the E2-E7 interaction in HPV-58, especially in viral tumorigenesis, was investigated. Results showed that, through interacting with 58E7, 58E2 prevented E7-induced retinoblastoma protein (pRb) degradation and prolonged the half-life of pRb in cells. Additionally, 58E2 abrogated 58E7-induced cell proliferation. These observations collectively suggest that direct interaction with 58E7 is another mechanism for 58E2 to inhibit 58E7-associated carcinogenesis in addition to regulating expression of the 58E7 gene. PMID:22442110

Wang, Xin; Qi, Mei; Yu, Xiuping; Yuan, Yan; Zhao, Weiming

2012-07-01

93

Production of Human Papilloma Virus Type 16 E6 Oncoprotein as a Recombinant Protein in Eukaryotic Cells  

PubMed Central

Background Cervical cancer is one of the most important and widespread cancer which affects women. There are several causes of cervical cancer; among them HPV types 16 and 18 are the most prominent ones which are recurrent and persistent infections. These genotypes are currently about 70% of cervical cancer causes in developing countries. Due to the importance of these viruses in cervical cancer, we pioneered the production of Human Papilloma Virus type16 E6 oncoprotein as a recombinant protein in order to develop a vaccine. Two HPV oncoproteins, E6 and E7, are consistently expressed in HPV-associated cancer cells and are responsible for malignant transformation. These oncogenic proteins represent ideal target antigens for developing vaccine and immunotherapeutic strategies against HPV-associated neoplasm. Methods In the present study, the cloned E6-oncoprotein of HPV16 in pTZ57R/T-E6 vector was used to produce professional expression vector. The target gene was subcloned in a eukaryotic expression vector. The pcDNA3-E6 vector was propagated in E.coli strain DH5? and transfected into CHO cells 72 hours post-transfection. Results The transfected cells were harvested; mRNA detection and the interest protein production were confirmed by western blot analysis using specific anti E6 monoclonal antibody. Conclusion HPV16-E6 target protein recognized by specific antibody could be an appropriate form of protein, which can be used for further studies. Due to potential effect of this protein, its DNA construction can be used for DNA vaccine in future studies.

Mirshahabi, H; Soleimanjahi, H; Pourpak, Z; Meshkat, Z; Hassan, ZM

2012-01-01

94

The multiple cellular functions of the oncoprotein Golgi phosphoprotein 3.  

PubMed

The highly conserved Golgi phosphoprotein 3 (GOLPH3) protein, a component of Trans-Golgi Network (TGN), has been defined as a "first-in-class Golgi oncoprotein" and characterized as a Phosphatidylinositol 4-phosphate [PI(4)P] effector at the Golgi. GOLPH3 is commonly amplified in several solid tumors. Furthermore this protein has been associated with poor prognosis in many cancers. Highly conserved from yeast to humans, GOLPH3 provides an essential function in vesicle trafficking and Golgi structure. Recent data have also implicated this oncoprotein in regulation of cytokinesis, modulation of mitochondrial mass and cellular response to DNA damage. A minute dissection of the molecular pathways that require GOLPH3 protein will be helpful to develop new therapeutic cancer strategies. PMID:25691054

Sechi, Stefano; Frappaolo, Anna; Belloni, Giorgio; Colotti, Gianni; Giansanti, Maria Grazia

2015-02-28

95

Prognostic value of oncoprotein expressions in thyroid papillary carcinoma.  

PubMed

The aim of this study was to evaluate the expressions of oncoproteins and to correlate the results with clinicopathologic parameters in papillary thyroid carcinoma (PTC). Papillary thyroid cancer (PTC) is the most common form and accounts for about 80% of all thyroid cancers. Although PTC generally has a good prognosis, some patients suffer from local recurrence and/or distant metastasis. Oncogenes have reported to be related not only in carcinogenesis but also in tumor prognosis, tumor type, differentiation and site of tumor in epithelial malignant tumors such as thyroid, breast, ovarian, and stomach cancer. This study was planned retrospectively and was performed in 87 patients (47 PTC, 40 benign lesions). The data of clinicopathologic parameters and tissue samples were collected from the archives. Sections stained with H&E were evaluated for each case and after confirming the diagnosis of PTC, oncoprotein expressions were determined by immunohistochemical analysis. The differences of oncoprotein expressions in PTC compared with control group were statistically significant. Cyclin D1 and p53 expressions were significantly increased in PTC. The expressions of bcl-2 and c-erbB-2 in PTC were found as increased, but the correlation between these proteins and poor prognostic parameters were not significant. We suggest that increased expressions of cyclin D1 and p53 could be used as prognostic factors in patients with PTC. PMID:21547408

Balta, A Z; Filiz, A I; Kurt, Y; Sucullu, I; Yucel, E; Akin, M L

2012-06-01

96

Protective effect of oxidative stress in HaCaT keratinocytes expressing E7 oncogene  

Microsoft Academic Search

Summary.  In a previous study, we established a stable cell line which constitutively expresses E7 in HaCaT human keratinocyte cell\\u000a line and identified various relevant factors including oxygen modulators affected by the E7 oncogene. E7-expressing HaCaT\\u000a cells (HaCaT\\/E7) appeared to be more resistant to H2O2-induced cell death. Here, we demonstrate how E7 oncogene would modulate oxidative stress-induced cell death. In addition,

J.-H. Shim; K.-H. Kim; Y.-S. Cho; H.-S. Choi; E. Y. Song; P.-K. Myung; J. S. Kang; S.-K. Suh; S. N. Park; D.-Y. Yoon

2008-01-01

97

NSD3-NUT Fusion Oncoprotein in NUT Midline Carcinoma: Implications for a Novel Oncogenic Mechanism  

PubMed Central

NUT midline carcinoma (NMC) is an aggressive subtype of squamous cell carcinoma that typically harbors BRD4/3-NUT fusion oncoproteins that block differentiation and maintain tumor growth. In 20% of cases NUT is fused to uncharacterized non-BRD gene(s). We established a new patient-derived NMC cell line (1221) and demonstrated that it harbors a novel NSD3-NUT fusion oncogene. We find that NSD3-NUT is both necessary and sufficient for the blockade of differentiation and maintenance of proliferation in NMC cells. NSD3-NUT binds to BRD4, and BRD bromodomain inhibitors induce differentiation and arrest proliferation of 1221 cells. We find further that NSD3 is required for the blockade of differentiation in BRD4-NUT-expressing NMCs. These findings identify NSD3 as a novel critical oncogenic component and potential therapeutic target in NMC. PMID:24875858

French, Christopher A.; Rahman, Shaila; Walsh, Erica M.; Kühnle, Simone; Grayson, Adlai R.; Lemieux, Madeleine E.; Grunfeld, Noam; Rubin, Brian P.; Antonescu, Cristina R.; Zhang, Songlin; Venkatramani, Rajkumar; Cin, Paola Dal; Howley, Peter M.

2014-01-01

98

Withaferin A induces p53-dependent apoptosis by repression of HPV oncogenes and upregulation of tumor suppressor proteins in human cervical cancer cells.  

PubMed

Cervical cancer is caused by human papilloma virus (HPV) expressing E6 and E7 oncoproteins, which are known to inactivate tumor suppressor proteins p53 and pRb, respectively. Repression of HPV oncoproteins would therefore result in reactivation of tumor suppressor pathways and cause apoptosis in cancer cells. Withaferin A (WA), the active component of the medicinal plant Withania Somnifera, has exhibited inhibitory effects against several different cancers. We examined the activity of WA on human cervical cancer cells in vitro and in vivo. WA potently inhibited proliferation of the cervical cancer cells, CaSki (IC(50) 0.45 ± 0.05 ?M). Mechanistically, WA was found to (i) downregulate expression of HPV E6 and E7 oncoproteins, (ii) induce accumulation of p53, (iii) increase levels of p21(cip1/waf1) and its interaction with proliferating cell nuclear antigen (PCNA), (iv) cause G(2)/M cell cycle arrest, associated with modulation of cyclin B1, p34(cdc2) and PCNA levels, (v) decrease the levels of STAT3 and its phosphorylation at Tyr(705) and Ser(727) and (vi) alter expression levels of p53-mediated apoptotic markers-Bcl2, Bax, caspase-3 and cleaved PARP. In vivo, WA resulted in reduction of nearly 70% of the tumor volume in athymic nude mice with essentially similar trend in the modulation of molecular markers as in vitro. This is the first demonstration indicating that WA significantly downregulates expression of HPV E6/E7 oncogenes and restores the p53 pathway, resulting in apoptosis of cervical cancer cells. Together, our data suggest that WA can be exploited as a potent therapeutic agent for the treatment and prevention of cervical cancer without deleterious effects. PMID:21859835

Munagala, Radha; Kausar, Hina; Munjal, Charu; Gupta, Ramesh C

2011-11-01

99

[Expression of epithelial oncoproteins in large intestine neoplasms].  

PubMed

The high incidence of the colorectal cancer in the industrialized countries has drawn the interest of the scientific community to detect and investigate its morphologic precursors. Growth factors and oncoproteins could be useful to investigate the morphologic and biologic evolution of precancerous lesions of the large bowel. Therefore the Authors report the results obtained from 30 selected patients with hyperplastic and adenomatous polyps, and different histotypes of colorectal cancer, investigated using the EGF-r and p62 protein expression. The results show the potential usefulness of such markers to evaluate the biology of intestinal tumors. PMID:12400211

Bufo, P; Losacco, T; Greco, L; Gagliardi, S; Logrieco, S; Santacroce, L

2002-01-01

100

Identification of novel E6-E7 sequence variants of human papillomavirus 16.  

PubMed

The rate of evolution of the human papillomavirus 16 (HPV16) genome is low. However, the ability of the E6 oncoprotein to interact with distinct p53 variants causes selective pressure on the E6 gene. In addition, intratypic recombination events in the HPV16 E6 and E7 genes have been characterized as extraordinary phenomena during the evolutionary history of virus. In the present study, we identified two new sequence variants through nucleotide analysis of the E6-E7 region of the HPV16 genome. Maximum-likelihood and empirical Bayesian methods were used in order to identify positive selection at particular residues of the E6 and E7 genes. Using the single recombination breakpoint (SBP) method, we found evidence of recombination events in the E6 ORF. Nucleotide sequence analysis showed that the new sequence variants are phylogenetically distant from the other members of the population. Our results indicate that new evolutionary intermediates of HPV16 might be formed either though positive selective pressure or through recombination events by multiple infections with distinct HPV16 variants. PMID:23208280

Tsakogiannis, D; Kyriakopoulou, Z; Amoutzias, G; Ruether, I G A; Dimitriou, T G; Panotopoulou, E; Markoulatos, P

2013-04-01

101

Protective effect of oxidative stress in HaCaT keratinocytes expressing E7 oncogene.  

PubMed

In a previous study, we established a stable cell line which constitutively expresses E7 in HaCaT human keratinocyte cell line and identified various relevant factors including oxygen modulators affected by the E7 oncogene. E7-expressing HaCaT cells (HaCaT/E7) appeared to be more resistant to H2O2-induced cell death. Here, we demonstrate how E7 oncogene would modulate oxidative stress-induced cell death. In addition, we verified the increased expression of catalase in the HaCaT/E7 by Western blot analysis. The results suggest that the E7 oncogene would induce higher resistance to ROS-induced cell injury in the E7-infected cells via the upregulation of catalase. To investigate these paradoxical effects of high concentrations of H2O2 (500 microM-1 mM), we examined their effects on receptor mediated apoptosis, cell death via the mitochondrial pathway and modulation of apoptosis related factors. Our results revealed that HaCaT keratinocytes infected with HPV 16 E7 oncogene modulated expressions of catalase, Bcl-xL, IL-18, Fas, Bad, and cytochrome c as well as NF-kappaB, resulting in the resistance to oxidative stress-induced cell death. PMID:17334903

Shim, J-H; Kim, K-H; Cho, Y-S; Choi, H-S; Song, E Y; Myung, P-K; Kang, J S; Suh, S-K; Park, S N; Yoon, D-Y

2008-01-01

102

E7 properties of mucosal human papillomavirus types 26, 53 and 66 correlate with their intermediate risk for cervical cancer development  

SciTech Connect

Epidemiological studies have demonstrated that 15 different mucosal human papillomavirus (HPV) types of the genus alpha of the HPV phylogetic tree are classified as high risk for cervical cancer development. Three additional HPV types of the same genus, HPV26, 53 and 66, are classified as probable high-risk types. In this study, we have characterized the biological properties of the E7 oncoproteins from these three HPV types. All of the corresponding E7 proteins were able to associate with retinoblastoma protein (pRb) and up-regulated the expression of several positive cell cycle regulators, i.e. CDK2, cyclin A and cylin E. However, HPV26 E7 appears to be more efficient than HPV53 and 66 E7 in up-regulating the transcription of cyclin A. Unlike E7 from the high-risk type HPV16 protein, HPV26, 53 and 66 did not efficiently promote pRb degradation. In addition, E7 from these viruses was able to promote proliferation of primary human keratinocytes and circumvent G1 arrest imposed by overexpression of p16{sup INK4a}, but with less efficiency than the high-risk HPV16 E7. Together, our data show that in vitro properties of these E7 proteins correlate with the epidemiological classification of HPV26, 53 and 66 as HPV types with an intermediate risk for cervical cancer development.

Mansour, Mariam; Touka, Majid; Hasan, Uzma; Bellopede, Angelica; Smet, Anouk; Accardi, Rosita; Gabet, Anne-Sophie; Sylla, Bakary S. [Infections and Cancer Biology Group, International Agency for Research on Cancer, 150 cours Albert-Thomas, 69008 Lyon (France); Tommasino, Massimo [Infections and Cancer Biology Group, International Agency for Research on Cancer, 150 cours Albert-Thomas, 69008 Lyon (France)], E-mail: tommasino@iarc.fr

2007-10-10

103

E7 properties of mucosal human papillomavirus types 26, 53 and 66 correlate with their intermediate risk for cervical cancer development.  

PubMed

Epidemiological studies have demonstrated that 15 different mucosal human papillomavirus (HPV) types of the genus alpha of the HPV phylogetic tree are classified as high risk for cervical cancer development. Three additional HPV types of the same genus, HPV26, 53 and 66, are classified as probable high-risk types. In this study, we have characterized the biological properties of the E7 oncoproteins from these three HPV types. All of the corresponding E7 proteins were able to associate with retinoblastoma protein (pRb) and up-regulated the expression of several positive cell cycle regulators, i.e. CDK2, cyclin A and cylin E. However, HPV26 E7 appears to be more efficient than HPV53 and 66 E7 in up-regulating the transcription of cyclin A. Unlike E7 from the high-risk type HPV16 protein, HPV26, 53 and 66 did not efficiently promote pRb degradation. In addition, E7 from these viruses was able to promote proliferation of primary human keratinocytes and circumvent G1 arrest imposed by overexpression of p16(INK4a), but with less efficiency than the high-risk HPV16 E7. Together, our data show that in vitro properties of these E7 proteins correlate with the epidemiological classification of HPV26, 53 and 66 as HPV types with an intermediate risk for cervical cancer development. PMID:17568647

Mansour, Mariam; Touka, Majid; Hasan, Uzma; Bellopede, Angelica; Smet, Anouk; Accardi, Rosita; Gabet, Anne-Sophie; Sylla, Bakary S; Tommasino, Massimo

2007-10-10

104

Apoptosis of mortal human fibroblasts transformed by the bovine papillomavirus E5 oncoprotein.  

PubMed

Mortal human fibroblasts can be partially transformed by the bovine papillomavirus E5 oncoprotein through activation of the platelet-derived growth factor beta receptor. Here, we report that these cells undergo massive apoptosis 2 weeks after confluence. Although activation of caspase 3 was observed in the apoptotic cells, it was not required for apoptosis. The appearance of the mitochondrial proteins cytochrome c and apoptosis-inducing factor in cytosolic and nuclear compartments, respectively, provided a basis for mitochondrial dysfunction and a caspase-independent mechanism of apoptosis in these cells. Although an activating conformational change in Bax also was evident in the apoptotic cells, enforced overexpression of Bcl-2 was insufficient to prevent apoptosis. Finally, a small peptide present in the conditioned medium from dying transformed cells appeared responsible for inducing apoptosis through affecting a conformational change in Bax and eventual relocalization of apoptosis-inducing factor to the nucleus. Thus, an atypical apoptotic pathway is activated in mortal human fibroblasts in response to transformation induced by sustained receptor tyrosine kinase activation. PMID:12496359

Zhang, Ying; Lehman, John M; Petti, Lisa M

2002-12-01

105

Impairment of the telomere/telomerase system and genomic instability are associated with keratinocyte immortalization induced by the skin human papillomavirus type 38.  

PubMed

The skin human papillomavirus (HPV) types belonging to the genus beta of the HPV phylogenetic tree appear to be associated with nonmelanoma skin cancer. We previously showed that the beta HPV type 38 E6 and E7 oncoproteins are able to inactivate the tumor suppressors p53 and retinoblastoma. Here, both viral proteins were expressed in primary human skin keratinocytes in order to study their effects on the telomere/telomerase system. We show that immortalization of skin keratinocytes induced by HPV38 E6/E7 is associated with hTERT gene overexpression. This event is, in part, explained by the accumulation of the p53-related protein, DeltaNp73. Despite elevated levels of hTERT mRNA, the telomerase activity detected in HPV38 E6/E7 keratinocytes was lower than that observed in HPV16 E6/E7 keratinocytes. The low telomerase activation in highly proliferative HPV38 E6/E7 keratinocytes resulted in the presence of extremely short and unstable telomeres. In addition, we observed anaphase bridges, mitotic multipolarity, and dramatic genomic aberrations. Interestingly, the ectopic expression of hTERT prevents both telomere erosion and genomic instability. Thus, we showed that in HPV38 E6/E7 keratinocytes characterized by unscheduled proliferation, suboptimal activation of telomerase and subsequent extensive telomere shortening result in genomic instability facilitating cellular immortalization. PMID:17898088

Gabet, Anne-Sophie; Accardi, Rosita; Bellopede, Angelica; Popp, Susanne; Boukamp, Petra; Sylla, Bakary S; Londoño-Vallejo, J Arturo; Tommasino, Massimo

2008-02-01

106

The oncoprotein HBXIP promotes migration of breast cancer cells via GCN5-mediated microtubule acetylation.  

PubMed

We have documented that the oncoprotein hepatitis B X-interacting protein (HBXIP) is able to promote migration of breast cancer cells. A subset of acetylated microtubules that accumulates in the cell leading edge is necessary for cell polarization and directional migration. In this study, we explored the hypothesis that HBXIP contributes to migration of breast cancer cells by supporting microtubule acetylation in breast cancer cells. We found that HBXIP could induce acetylated microtubules accumulating into the leading protrusion in wound-induced directional migration in breast cancer cells by immunofluorescence staining analysis. Interestingly, HBXIP was able to increase the acetylation of ?-tubulin in the cells by immunofluorescence staining and Western blot analysis. Furthermore, we observed that acetyltransferase GCN5 was involved in the event that HBXIP induced increase of acetylated microtubules and their expansion in protrusions in breast cancer cells by Western blot analysis and immunofluorescence staining. Moreover, GCN5 was required for the HBXIP-enhanced migration of breast cancer cells by wound healing assay. Thus, we conclude that HBXIP promotes the migration of breast cancer cells through modulating microtubule acetylation mediated by GCN5. Therapeutically, HBXIP may serve as a novel target in breast cancer. PMID:25686500

Li, Leilei; Liu, Bowen; Zhang, Xiaodong; Ye, Lihong

2015-03-13

107

University of Pittsburgh Cancer Institute researchers identify key oncoprotein found in Merkel Cell Carcinoma:  

Cancer.gov

Researchers at the University of Pittsburgh Cancer Institute (UPCI) have identified the oncoprotein that allows a common and usually harmless virus to transform healthy cells into a rare but deadly skin cancer called Merkel Cell Carcinoma (MCC).

108

Ha-ras and ?-catenin oncoproteins orchestrate metabolic programs in mouse liver tumors.  

PubMed

The process of hepatocarcinogenesis in the diethylnitrosamine (DEN) initiation/phenobarbital (PB) promotion mouse model involves the selective clonal outgrowth of cells harboring oncogene mutations in Ctnnb1, while spontaneous or DEN-only-induced tumors are often Ha-ras- or B-raf-mutated. The molecular mechanisms and pathways underlying these different tumor sub-types are not well characterized. Their identification may help identify markers for xenobiotic promoted versus spontaneously occurring liver tumors. Here, we have characterized mouse liver tumors harboring either Ctnnb1 or Ha-ras mutations via integrated molecular profiling at the transcriptional, translational and post-translational levels. In addition, metabolites of the intermediary metabolism were quantified by high resolution (1)H magic angle nuclear magnetic resonance. We have identified tumor genotype-specific differences in mRNA and miRNA expression, protein levels, post-translational modifications, and metabolite levels that facilitate the molecular and biochemical stratification of tumor phenotypes. Bioinformatic integration of these data at the pathway level led to novel insights into tumor genotype-specific aberrant cell signaling and in particular to a better understanding of alterations in pathways of the cell intermediary metabolism, which are driven by the constitutive activation of the ?-Catenin and Ha-ras oncoproteins in tumors of the two genotypes. PMID:24535843

Unterberger, Elif B; Eichner, Johannes; Wrzodek, Clemens; Lempiäinen, Harri; Luisier, Raphaëlle; Terranova, Rémi; Metzger, Ute; Plummer, Simon; Knorpp, Thomas; Braeuning, Albert; Moggs, Jonathan; Templin, Markus F; Honndorf, Valerie; Piotto, Martial; Zell, Andreas; Schwarz, Michael

2014-10-01

109

Cell-surface display of E7 antigen from human papillomavirus type-16 in Lactococcus lactis and in Lactobacillus plantarum using a new cell-wall anchor from lactobacilli.  

PubMed

The human papillomavirus type-16 (HPV-16) E7 protein is considered a major viral oncoprotein involved in cervical cancer (CxCa) and a potential candidate for the development of a vaccine against this neoplasia. Here, two lactic acid bacteria (the model one Lactococcus lactis and a probiotic one Lactobacillus plantarum) were engineered to deliver an E7 mutant protein (E7mm), which has a reduced transforming activity and consequently, could fit better to therapeutic use in humans than the native form of E7. An efficient cell-surface display of E7mm was obtained in L. lactis using an expression cassette encoding a precursor composed of (i) the signal peptide and the first 15 amino acids of the mature part of the lactococcal Usp45 protein; (ii) E7mm and (iii) the cell-wall anchor of the Streptococcus pyogenes M6 protein (CWA(M6)). This hybrid precursor was produced but not cell-wall anchored in Lb. plantarum. We thus replaced CWA(M6) by the cell-wall anchor of a Lb. plantarum protein which allows an efficient cell-wall anchoring of E7mm in this bacterium. The E7mm production and cell-surface display in both L. lactis and a probiotic bacterium, Lb. plantarum, represent one more step towards the development of a safe and effective treatment against CxCa. PMID:15823960

Cortes-Perez, Naima G; Azevedo, Vasco; Alcocer-González, Juan M; Rodriguez-Padilla, Cristina; Tamez-Guerra, Reyes S; Corthier, Gérard; Gruss, Alexandra; Langella, Philippe; Bermúdez-Humarán, Luis G

2005-02-01

110

Gaugings from E7 (7 ) extended geometries  

NASA Astrophysics Data System (ADS)

We discuss the construction of gaugings in recent models of E7 extended geometries, focusing on the two inequivalent S L (8 ) truncations of the theory. In these sectors the conditions for the generation of gaugings in the 36 , 36' , 420 and 420' representations of E7 (7 ) can be compactly expressed in terms of objects which are in the fundamental representation of S L (8 ), making the search of solutions simpler. We present a no-go theorem showing that neither of these truncations lead to the new S O (8 ) dyonic gaugings, at least if the so-called section conditions are implemented. We also show that these truncations can be used to obtain the generalized twist of the seven-sphere, leading to the electric S O (8 ) gaugings.

Baron, Walter H.

2015-01-01

111

NFKB1 Is a Direct Target of the TAL1 Oncoprotein in Human T Leukemia Cells  

E-print Network

NFKB1 Is a Direct Target of the TAL1 Oncoprotein in Human T Leukemia Cells Pei-Yun Chang, 1 Kyle Abstract We recently showed that a subset of human T acute lymphoblastic leukemia (T-ALL) cell lines in CEM T leukemia cells, basal NFKB1 expression is increased, and the levels of p65:cRel complex

Miyamoto, Shigeki

112

Problem-Solving Test: The Mechanism of Action of a Human Papilloma Virus Oncoprotein  

ERIC Educational Resources Information Center

Terms to be familiar with before you start to solve the test: human papilloma virus; cervical cancer; oncoproteins; malignant transformation; retinoblastoma protein; cell cycle; quiescent and cycling cells; cyclin/cyclin-dependent kinase (Cdk) complexes; E2F; S-phase genes; enhancer element; proto-oncogenes; tumor suppressor genes; radioactive…

Szeberenyi, Jozsef

2009-01-01

113

Artificial transmembrane oncoproteins smaller than the2 bovine papillomavirus E5 protein redefine sequence requirements3  

E-print Network

KTS 1 1 Artificial transmembrane oncoproteins smaller than the2 bovine papillomavirus E5 protein; bovine papillomavirus21 Word count: Abtract = 190; Text = 8,63722 * Corresponding author: Tel: 203.asm.orgDownloadedfrom #12;KTS 2 ABSTRACT24 The bovine papillomavirus E5 protein (BPV E5) is a 44-amino acid homodimeric25

Gerstein, Mark

114

The high-risk HPV E6 oncoprotein preferentially targets phosphorylated nuclear forms of hDlg  

SciTech Connect

High-risk mucosal HPV E6 oncoproteins target a number of PDZ domain-containing substrates for proteasome mediated degradation. One of these, Discs Large (Dlg), is involved in the regulation of cell polarity and proliferation control. Previous studies had suggested that Dlg when hyperphosphorylated by osmotic shock, or when present in the nucleus could be preferentially targeted by E6. In this study we use phospho-specific antibodies directed against Dlg phosphorylated at residues S158 and S442 to show that these two observations are, in fact, linked. Dlg, when phosphorylated on S158 and S442 by CDK1 or CDK2, shows a preferential nuclear accumulation. However, these forms of Dlg are absent in cells derived from HPV-induced cervical cancers. Upon either proteasome inhibition or siRNA ablation of E6 expression, we see specific rescue of these phosphorylated forms of Dlg. These results demonstrate that nuclear forms of Dlg phosphorylated on its CDK phospho-acceptor sites has enhanced susceptibility to E6-induced degradation and place previous studies on the stress-induced phosphorylation of Dlg into a relevant biological context.

Narayan, Nisha; Subbaiah, Vanitha Krishna [Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Trieste, TS 34012 (Italy); Banks, Lawrence, E-mail: banks@icgeb.or [Tumour Virology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, Trieste, TS 34012 (Italy)

2009-04-25

115

Ubiquitination and degradation of the hominoid-specific oncoprotein TBC1D3 is regulated by protein palmitoylation  

SciTech Connect

Highlights: •Hominoid-specific oncogene TBC1D3 is targeted to plasma membrane by palmitoylation. •TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. •TBC1D3 palmitoylation governs growth factors-induced TBC1D3 degradation. •Post-translational modifications may regulate oncogenic properties of TBC1D3. -- Abstract: Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis.

Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Su, Xiong [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Liu, Jialiu [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Sundaresan, Sinju [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Stahl, Philip D., E-mail: pstahl@wustl.edu [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)

2013-05-03

116

Fusion of CTLA-4 with HPV16 E7 and E6 Enhanced the Potency of Therapeutic HPV DNA Vaccine  

PubMed Central

Preventive anti-HPV vaccines are effective against HPV infection but not against existing HPV-associated diseases, including cervical cancer and other malignant diseases. Therefore, the development of therapeutic vaccines is urgently needed. To improve anti-tumor effects of therapeutic vaccine, we fused cytotoxic T-lymphocyte antigen 4 (CTLA-4) with HPV16 E7 and E6 as a fusion therapeutic DNA vaccine (pCTLA4-E7E6). pCTLA4-E7E6 induced significantly higher anti-E7E6 specific antibodies and relatively stronger specific CTL responses than the nonfusion DNA vaccine pE7E6 in C57BL/6 mice bearing with TC-1 tumors. pCTLA4-E7E6 showed relatively stronger anti-tumor effects than pE7E6 in therapeutic immunization. These results suggest that fusing CTLA-4 with E7E6 is a useful strategy to develop therapeutic HPV DNA vaccines. In addition, fusing the C-terminal of E7 with the N-terminal of E6 impaired the functions of both E7 and E6. PMID:25265018

Gan, Lili; Jia, Rong; Zhou, Lili; Guo, Jihua; Fan, Mingwen

2014-01-01

117

HPV16-E7 Expression in Squamous Epithelium Creates a Local Immune Suppressive Environment via CCL2- and CCL5- Mediated Recruitment of Mast Cells  

PubMed Central

Human Papillomavirus (HPV) 16 E7 protein promotes the transformation of HPV infected epithelium to malignancy. Here, we use a murine model in which the E7 protein of HPV16 is expressed as a transgene in epithelium to show that mast cells are recruited to the basal layer of E7-expressing epithelium, and that this recruitment is dependent on the epithelial hyperproliferation induced by E7 by inactivating Rb dependent cell cycle regulation. E7 induced epithelial hyperplasia is associated with increased epidermal secretion of CCL2 and CCL5 chemokines, which attract mast cells to the skin. Mast cells in E7 transgenic skin, in contrast to those in non-transgenic skin, exhibit degranulation. Notably, we found that resident mast cells in E7 transgenic skin cause local immune suppression as evidenced by tolerance of E7 transgenic skin grafts when mast cells are present compared to the rejection of mast cell-deficient E7 grafts in otherwise competent hosts. Thus, our findings suggest that mast cells, recruited towards CCL2 and CCL5 expressed by epithelium induced to proliferate by E7, may contribute to an immunosuppressive environment that enables the persistence of HPV E7 protein induced pre-cancerous lesions. PMID:25340820

Bergot, Anne-Sophie; Ford, Neill; Leggatt, Graham R.

2014-01-01

118

Cysteine-rich positions outside the structural zinc motif of human papillomavirus E7 provide conformational modulation and suggest functional redox roles.  

PubMed

The E7 protein from high-risk human papillomavirus is essential for cell transformation in cervical, oropharyngeal, and other HPV-related cancers, mainly through the inactivation of the retinoblastoma (Rb) tumor suppressor. Its high cysteine content (~7%) and the observation that HPV-transformed cells are under oxidative stress prompted us to investigate the redox properties of the HPV16 E7 protein under biologically compatible oxidative conditions. The seven cysteines in HPV16 E7 remain reduced in conditions resembling the basal reduced state of a cell. However, under oxidative stress, a stable disulfide bridge forms between cysteines 59 and 68. Residue 59 has a protective effect on the other cysteines, and its mutation leads to an overall increase in the oxidation propensity of E7, including cysteine 24 central to the Rb binding motif. Gluthationylation of Cys 24 abolishes Rb binding, which is reversibly recovered upon reduction. Cysteines 59 and 68 are located 18.6 Å apart, and the formation of the disulfide bridge leads to a large structural rearrangement while retaining strong Zn association. These conformational and covalent changes are fully reversible upon restoration of the reductive environment. In addition, this is the first evidence of an interaction between the N-terminal intrinsically disordered and the C-terminal globular domains, known to be highly and separately conserved among human papillomaviruses. The significant conservation of such noncanonical cysteines in HPV E7 proteins leads us to propose a functional redox activity. Such an activity adds to the previously discovered chaperone activity of E7 and supports the picture of a moonlighting pathological role of this paradigmatic viral oncoprotein. PMID:24559112

Chemes, Lucía B; Camporeale, Gabriela; Sánchez, Ignacio E; de Prat-Gay, Gonzalo; Alonso, Leonardo G

2014-03-18

119

Immunization with mutant HPV16 E7 protein inhibits the growth of TC-1 cells in tumor-bearing mice  

PubMed Central

Two human papillomavirus (HPV) 16 oncogenic proteins, E6 and E7, are co-expressed in the majority of HPV16-induced cervical cancer cells. Thus, the E6 and E7 proteins are good targets for developing therapeutic vaccines for cervical cancer. In the present study, immunization with the mutant non-transforming HPV16 E7 (mE7) protein was demonstrated to inhibit the growth of TC-1 cells in the TC-1 mouse model. The HPV16 mE7 gene was amplified by splicing overlap extension polymerase chain reaction using pET-28a(+)-E7 as a template, and the gene was cloned into pET-28a(+) to form pET-28a(+)-mE7. Compared with the E7 protein, mE7 lacks amino acid residues 94–98, and at residue 24, there is a Cys to Gly substitution. pET-28a(+)-mE7 was then introduced into Escherichia coli Rosetta. The expression of mE7 was induced by isopropyl ?-D-1-thiogalactopyranoside. The mE7 protein was purified using Ni-NTA agarose and detected by SDS-PAGE and western blot analysis. In the tumor prevention model, no tumor was detected in the mice vaccinated with the mE7 protein. After 40 days, the tumor-free mice and control mice were challenged with 2×105 TC-1 cells. All control mice developed tumors six days later, but mE7 immunized mice were tumor free until 90 days. In the tumor therapy model, the TC-1 cells were initially injected subcutaneously, and the mice were subsequently vaccinated. Vaccination against the mE7 protein may significantly inhibit TC-1 cell growth compared to the control. These results demonstrated that immunization with the HPV16 mE7 protein elicited a long-term protective immunity against TC-1 tumor growth and generated a significant inhibition of TC-1 growth in a TC-1 mouse model.

LI, YAN-LI; MA, ZHONG-LIANG; ZHAO, YUE; ZHANG, JING

2015-01-01

120

Oncoprotein MDM2 is a ubiquitin ligase E3 for tumor suppressor p53  

Microsoft Academic Search

The tumor suppressor p53 is degraded by the ubiquitin-proteasome system. p53 was polyubiquitinated in the presence of E1, UbcH5 as E2 and MDM2 oncoprotein. A ubiquitin molecule bound MDM2 through sulfhydroxy bond which is characteristic of ubiquitin ligase (E3)-ubiquitin binding. The cysteine residue in the carboxyl terminus of MDM2 was essential for the activity. These data suggest that the MDM2

Reiko Honda; Hirofumi Tanaka; Hideyo Yasuda

1997-01-01

121

Human papillomavirus (HPV) type 16 E7 protein bodies cause tumour regression in mice  

PubMed Central

Background Human papillomaviruses (HPV) are the causative agents of cervical cancer in women, which results in over 250 000 deaths per year. Presently there are two prophylactic vaccines on the market, protecting against the two most common high-risk HPV types 16 and 18. These vaccines remain very expensive and are not generally affordable in developing countries where they are needed most. Additionally, there remains a need to treat women that are already infected with HPV, and who have high-grade lesions or cervical cancer. Methods In this paper, we characterize the immunogenicity of a therapeutic vaccine that targets the E7 protein of the most prevalent high-risk HPV - type 16 – the gene which has previously been shown to be effective in DNA vaccine trials in mice. The synthetic shuffled HPV-16 E7 (16E7SH) has lost its transforming properties but retains all naturally-occurring CTL epitopes. This was genetically fused to Zera®, a self-assembly domain of the maize ?-zein able to induce the accumulation of recombinant proteins into protein bodies (PBs), within the endoplasmic reticulum in a number of expression systems. Results High-level expression of the HPV 16E7SH protein fused to Zera® in plants was achieved, and the protein bodies could be easily and cost-effectively purified. Immune responses comparable to the 16E7SH DNA vaccine were demonstrated in the murine model, with the protein vaccine successfully inducing a specific humoral as well as cell mediated immune response, and mediating tumour regression. Conclusions The fusion of 16E7SH to the Zera® peptide was found to enhance the immune responses, presumably by means of a more efficient antigen presentation via the protein bodies. Interestingly, simply mixing the free PBs and 16E7SH also enhanced immune responses, indicating an adjuvant activity for the Zera® PBs. PMID:24885328

2014-01-01

122

The proto-oncoprotein SYT (SS18) controls ATP release and regulates cyst formation by polarized MDCK cells.  

PubMed

The SYT proto-oncoprotein (also known as SS18) is a gene expression regulator conserved across species. Although its biological function is still unknown, the importance of SYT as a housekeeping protein is illustrated by the lethal phenotype of SYT-null embryos. Notably, SYT is a component of the synovial sarcoma-associated translocation product, the SYT-SSX oncogene. SYT was previously reported as a mediator of cell adhesion. In the present study we show that SYT possesses distinct domains that control MDCK cyst formation in three-dimensional collagen cultures. While the carboxy-half of SYT, the QPGY domain, is required for cyst growth, the amino-terminal region appears to exert on this process a regulatory effect. Further analysis suggested that the purinergic G protein-coupled P2Y receptor signaling is involved in SYT-induced cystogenesis. Activation of this cascade is due to facilitation of ATP release in the extracellular space of polarized MDCK cells by SYT. These studies allow us to begin to understand the vital role of SYT in controlling epithelial morphogenesis and might explain the lethality of its loss in the developing embryo. PMID:18835266

Chittezhath, Manesh; Frump, Andrea L; Jourquin, Jerome; Lobdell, Nichole; Eid, Josiane E

2008-11-15

123

The proto-oncoprotein SYT (SS18) controls ATP release and regulates cyst formation by polarized MDCK cells  

PubMed Central

The SYT proto-oncoprotein (also known as SS18) is a gene expression regulator conserved across species. Although its biological function is still unknown, the importance of SYT as a housekeeping protein is illustrated by the lethal phenotype of SYT-null embryos. Notably, SYT is a component of the synovial sarcoma-associated translocation product, the SYT-SSX oncogene. SYT was previously reported as a mediator of cell adhesion. In the present study we show that SYT possesses distinct domains that control MDCK cyst formation in three-dimensional collagen cultures. While the carboxy-half of SYT, the QPGY domain, is required for cyst growth, the amino-terminal region appears to exert on this process a regulatory effect. Further analysis suggested that the purinergic G protein-coupled P2Y receptor signaling is involved in SYT-induced cystogenesis. Activation of this cascade is due to facilitation of ATP release in the extracellular space of polarized MDCK cells by SYT. These studies allow us to begin to understand the vital role of SYT in controlling epithelial morphogenesis and might explain the lethality of its loss in the developing embryo. PMID:18835266

Chittezhath, Manesh; Frump, Andrea L; Jourquin, Jerome; Lobdell, Nichole; Eid, Josiane E

2008-01-01

124

Merkel Cell Polyomavirus Small T Antigen Controls Viral Replication and Oncoprotein Expression by Targeting the Cellular Ubiquitin Ligase SCFFbw7  

PubMed Central

SUMMARY Merkel cell polyomavirus (MCV) causes an aggressive human skin cancer, Merkel cell carcinoma, through expression of small T (sT) and large T (LT) viral oncoproteins. MCV sT is also required for efficient MCV DNA replication by the multifunctional MCV LT helicase protein. We find that LT is targeted for proteasomal degradation by the cellular SCFFbw7 E3 ligase, which can be inhibited by sT through its LT stabilization domain (LSD). Consequently, sT also stabilizes cellular SCFFbw7 targets, including the cell cycle regulators c-Myc and cyclin E. Mutating the sT LSD decreases LT protein levels and eliminates synergism in MCV DNA replication as well as sT-induced cell transformation. SCFFbw7 knockdown mimics sT-mediated stabilization of LT, but this knockdown is insufficient to fully reconstitute the transforming activity of a mutant LSD sT protein. Thus, MCV has evolved a regulatory system involving SCFFbw7 that controls viral replication but also contributes to host cell transformation. PMID:23954152

Kwun, Hyun Jin; Shuda, Masahiro; Feng, Huichen; Camacho, Carlos J.; Moore, Patrick S.; Chang, Yuan

2013-01-01

125

Chimeric Infectious Bursal Disease Virus-Like Particles as Potent Vaccines for Eradication of Established HPV-16 E7–Dependent Tumors  

PubMed Central

Cervical cancer is caused by persistent high-risk human papillomavirus (HR-HPV) infection and represents the second most frequent gynecological malignancy in the world. The HPV-16 type accounts for up to 55% of all cervical cancers. The HPV-16 oncoproteins E6 and E7 are necessary for induction and maintenance of malignant transformation and represent tumor-specific antigens for targeted cytotoxic T lymphocyte–mediated immunotherapy. Therapeutic cancer vaccines have become a challenging area of oncology research in recent decades. Among current cancer immunotherapy strategies, virus-like particle (VLP)–based vaccines have emerged as a potent and safe approach. We generated a vaccine (VLP-E7) incorporating a long C-terminal fragment of HPV-16 E7 protein into the infectious bursal disease virus VLP and tested its therapeutic potential in HLA-A2 humanized transgenic mice grafted with TC1/A2 tumor cells. We performed a series of tumor challenge experiments demonstrating a strong immune response against already-formed tumors (complete eradication). Remarkably, therapeutic efficacy was obtained with a single dose without adjuvant and against two injections of tumor cells, indicating a potent and long-lasting immune response. PMID:23300838

González-Cintado, Leticia; Kowalczyk, Wioleta; Jimenez Torres, Ignacio; Calderita, Gloria; Rodriguez, Margarita; Gondar, Virgínia; Bernal, Juan Jose; Ardavín, Carlos; Andreu, David; Zürcher, Thomas; von Kobbe, Cayetano

2012-01-01

126

Immunomodulatory activity of a plant extract containing human papillomavirus 16-E7 protein in human monocyte-derived dendritic cells.  

PubMed

This study reports the immunomodulatory activity on human monocyte derived dendritic cells (MDDCs) of a vaccine preparation shown to be effective against an HPV16-related tumour in an animal model. The vaccine is composed of extract from Nicotiana benthamiana leaves containing HPV16 E7 protein expressed by a potato virus X-derived vector (NbPVX-E7). The effect of the extract was evaluated on MDDC differentiation and maturation by monitoring the phenotypic expression of specific markers. The results show that NbPVX-E7 does not induce monocyte differentiation to dendritic cells, but does induce MDDC maturation. Plant extract does not influence MDDC-uptake of E7-FITC while it significantly improves the Ovalbumin-FITC uptake, considered as a model antigen. Importantly, NbPVX-E7-pulsed MDDCs/PBMCs are able to prime human blood-derived lymphocytes from healthy individuals to induce HPV16 E7-specific cytotoxic activity. This is a propaedeutic study for a possible use of E7-containing plant extract in human immunotherapy of HPV-related lesions. PMID:20074460

Di Bonito, P; Grasso, F; Mangino, G; Massa, S; Illiano, E; Franconi, R; Fanales-Belasio, E; Falchi, M; Affabris, E; Giorgi, C

2009-01-01

127

Papillomavirus E7 protein binding to the retinoblastoma protein is not required for viral induction of warts.  

PubMed Central

Human papillomaviruses (HPVs) are the etiologic agents responsible for benign epithelial proliferative disorders including genital warts and are a contributory factor in the pathogenesis of cervical cancer. HPVs demonstrate strict species and cell-type specificity, which is manifested by the inability of these viruses to induce disease in any species other than humans. The natural history of HPV infection in humans is closely mimicked by cottontail rabbit papillomavirus (CRPV) infection in domestic laboratory rabbits. The CRPV E7 gene is known to play an essential role in virus-mediated induction of papillomas. We now show by mutational analysis that the CRPV E7 protein's biochemical and biological properties, including binding to the retinoblastoma suppressor protein (pRB), transcription factor E2F transactivation of the adenovirus E2 promoter, disruption of pRB-E2F complexes, and cellular transformation as measured by growth in soft agar, mimic those of the HPV E7 protein. Intradermal injection of CRPV DNA lacking E7 gene sequences critical for the binding of the CRPV E7 protein to pRB induced papillomas in rabbits. These studies indicate that E7 protein binding to pRB is not required in the molecular pathogenesis of virally induced warts and suggest that other properties intrinsic to the E7 protein are necessary for papilloma formation. Images PMID:8380462

Defeo-Jones, D; Vuocolo, G A; Haskell, K M; Hanobik, M G; Kiefer, D M; McAvoy, E M; Ivey-Hoyle, M; Brandsma, J L; Oliff, A; Jones, R E

1993-01-01

128

Impairment of the telomere\\/telomerase system and genomic instability are associated with keratinocyte immortalization induced by the skin human papillomavirus type 38  

Microsoft Academic Search

The skin human papillomavirus (HPV) types belonging to the genus beta of the HPV phyloge- netic tree appear to be associated with nonmelanoma skin cancer. We previously showed that the beta HPV type 38 E6 and E7 oncoproteins are able to inactivate the tumor suppressors p53 and retinoblastoma. Here, both viral proteins were expressed in primary human skin keratinocytes in

Anne-Sophie Gabet; Rosita Accardi; Angelica Bellopede; Susanne Popp; Petra Boukamp; Bakary S. Sylla; J. Arturo Londono-Vallejo; Massimo Tommasino

2007-01-01

129

Direct Binding of the N-Terminus of HTLV-1 Tax Oncoprotein to Cyclin-Dependent Kinase 4 Is a Dominant Path To Stimulate the Kinase Activity  

E-print Network

Direct Binding of the N-Terminus of HTLV-1 Tax Oncoprotein to Cyclin-Dependent Kinase 4: The involvement of Tax oncoprotein in the INK4-CDK4/6-Rb pathway has been regarded as a key factor -/- and +/+ cells, expression of Tax has been correlated with an increase in CDK4 activity, which subsequently

Tsai, Ming-Daw

130

The E6 and E7 Proteins of the Cutaneous Human Papillomavirus Type 38 Display Transforming Properties  

Microsoft Academic Search

Several studies have suggested the involvement of cutaneous human papillomaviruses (HPVs) in the development of nonmelanoma skin cancers. Here we have characterized the in vitro properties of E7 proteins of three cutaneous HPV types, 10, 20, and 38, which are frequently detected in skin specimens. We show that HPV38 E7 is able to inactivate the tumor suppressor pRb and induces

Sandra Caldeira; Ingeborg Zehbe; Rosita Accardi; Ilaria Malanchi; Wen Dong; Marianna Giarre; Ethel-Michele de Villiers; Raffaele Filotico; Petra Boukamp; Massimo Tommasino

2003-01-01

131

SA-4-1BBL as the immunomodulatory component of a HPV-16 E7 protein based vaccine shows robust therapeutic efficacy in a mouse cervical cancer model  

PubMed Central

Cervical cancer is the leading cause of cancer-related deaths among women worldwide. Current prophylactic vaccines based on HPV (Human papillomavirus) late gene protein, L1 are ineffective in therapeutic settings. Therefore, there is an acute need for the development of therapeutic vaccines for HPV associated cancers. The HPV E7 oncoprotein is expressed in cervical cancer and has been associated with the cellular transformation and maintenance of the transformed phenotype. As such, E7 protein represents an ideal target for the development of therapeutic subunit vaccines against cervical cancer. However, the low antigenicity of this protein may require potent adjuvants for therapeutic efficacy. We recently generated a novel chimeric form of the 4-1BBL costimulatory molecule engineered with core streptavidin (SA-4-1BBL) and demonstrated its safe and pleiotropic effects on various cells of the immune system. We herein tested the utility of SA-4-1BBL as the immunomodulatory component of HPV-16 E7 recombinant protein based therapeutic vaccine in the E7 expressing TC-1 tumor as a model of cervical cancer in mice. A single subcutaneous vaccination was effective in eradicating established tumors in approximately 70% of mice. The therapeutic efficacy of the vaccine was associated with robust primary and memory CD4+ and CD8+ T cell responses, Th1 cytokine response, infiltration of CD4+ and CD8+ T cells into the tumor, and enhanced NK cell killing. Importantly, NK cells played an important role in vaccine mediated therapy since their physical depletion compromised vaccine efficacy. Collectively, these data demonstrate the utility of SA-4-1BBL as a new class of multifunctional immunomodulator for the development of therapeutic vaccines against cancer and chronic infections. PMID:20603135

Sharma, Rajesh K.; Srivastava, Abhishek K.; Yolcu, Esma S.; MacLeod, Kathryn J.; Schabowsky, Rich-Henry; Madireddi, Shravan; Shirwan, Haval

2010-01-01

132

Phosphatidylinositol 3-kinase (PI3K): The Oncoprotein  

PubMed Central

The catalytic and regulatory subunits of class I phosphoinositide 3-kinase (PI3K) have oncogenic potential. The catalytic subunit p110? and the regulatory subunit p85 undergo cancer-specific gain-of-function mutations that lead to enhanced enzymatic activity, ability to signal constitutively and oncogenicity. The ?, ? and ? isoforms of p110 are cell-transforming as overexpressed wild-type proteins. Class I PI3Ks have the unique ability to generate phosphoinositide 3,4,5 trisphosphate (PIP3). Class II and class III PI3Ks lack this ability. Genetic and cell biological evidence suggests that PIP3 is essential for PI3K-mediated oncogenicity, explaining why class II and class III enzymes have not been linked to cancer. Mutational analysis reveals the existence of at least two distinct molecular mechanisms for the gain of function seen with cancer-specific mutations in p110?, one causing independence from upstream receptor tyrosine kinases, the other inducing independence from Ras. An essential component of the oncogenic signal that is initiated by PI3K is the TOR (target of rapamycin) kinase. TOR is an integrator of growth and of metabolic inputs. In complex with the raptor protein (TORC1), it controls cap-dependent translation, and this function is essential for PI3K-initiated oncogenesis. PMID:20582532

Vogt, Peter K.; Hart, Jonathan R.; Gymnopoulos, Marco; Jiang, Hao; Kang, Sohye; Bader, Andreas G.; Zhao, Li; Denley, Adam

2010-01-01

133

The contribution of NT-gp96 as an adjuvant for increasing HPV16 E7-specific immunity in C57BL?/6 mouse model.  

PubMed

To control cervical cancer, efficient vaccination against human papillomavirus (HPV) is highly required. Despite the advantages and safety of the protein vaccines, additional strategies to enhance their immunogenicity are needed. E7 is a transforming protein which represents a perfect target antigen for vaccines or immunotherapies. Heat shock proteins (HSPs) facilitate cellular immune responses to antigenic peptides or proteins bound to them. Regarding to previous studies, vaccination with purified HSP/antigen complexes efficiently elicit antigen-specific immune responses in mice model. The N-terminal of glycoprotein 96 (NT-gp96) has adjuvant effect and can induce effective cumulative immune response against clinical disorders, especially cancers. In this study, the recombinant HPV16 E7 and E7 linked to NT-gp96 (E7-NT-gp96) proteins were generated in prokaryotic expression system. Mice were vaccinated twice with this recombinant proteins and the immunogenicity of the fusion protein was determined. The preventive efficacy of E7-NT-gp96 fusion protein was also evaluated and compared to E7 protein after challenging with cancerous TC-1 cell line. In vitro re-stimulated splenocytes of mice vaccinated with rE7-NT-gp96 protein induced higher IFN-? response in comparison with E7 protein immunization. Moreover, immunization with E7-NT-gp96 protein displayed low but stable humoral responses at post-challenge time. The data showed that vaccination with fused E7-NT-gp96 protein delayed the tumour occurrence and growth as compared to protein E7 alone. These results suggest that fused adjuvant-free E7-NT-gp96 protein vaccination could direct the immune responses towards Th1 immunity. Furthermore, the linkage of NT-gp96 to E7 could enhance protective anti-tumour immunity. PMID:21916914

Mohit, E; Bolhassani, A; Zahedifard, F; Taslimi, Y; Rafati, S

2012-01-01

134

Molecular genetic characterization of p53 mutated oropharyngeal squamous cell carcinoma cells transformed with human papillomavirus E6 and E7 oncogenes.  

PubMed

Patients with HPV-positive oropharyngeal cancer show better tumor response to radiation or chemotherapy than patients with HPV-negative cancer. HPV oncoprotein E6 binds and degrades a typically wild-type p53 protein product. However, HPV16 infection and p53 mutation infrequently coexist in a subset of HNSCCs. The purpose of this study was to investigate the mechanisms through which tumor biology and molecular genetic mechanisms change when two HPV-negative, p53-mutated oropharyngeal cell lines (YD8, non-disruptive p53 mutation; YD10B, disruptive p53 mutation) derived from patients with a history of heavy smoking are transfected with HPV E6 and E7 oncogenes in vitro. Transfection with HPV E6 and E7 oncogenes in YD8, reduced the abundance of proteins encoded by tumor suppressor genes, such as p-p53 and p-Rb. Cell proliferative activity was increased in the cells transfected with E6E7 compared to cells transfected with vector alone (P=0.09), whereas the invasiveness of E6E7-transfected cells was significantly reduced (P=0.02). cDNA microarray of the transfected cells with E6E7 showed significant changes in mRNA expression in several signaling pathways, including focal adhesion, JAK-STAT signaling pathway, cell cycle and p53 signaling pathway. Regarding the qPCR array for the p53 signaling pathway, the mRNA expression of STAT1 was remarkably upregulated by 6.47-fold (P<0.05); in contrast, IGF-1R was significantly downregulated by 2.40-fold in the YD8-vector compared toYD8-E6E7 (P<0.01). Finally, data collected from these two array experiments enabled us to select two genes, STAT1 and IGF-1R, for further study. In immunohistochemical study, nuclear STAT1 expression was slightly higher in HPV-positive compared to HPV-negative oropharyngeal tumors (P=0.18); however, cytoplasmic STAT1 was significantly lower in HPV-positive cases (P=0.03). IGF-1R expression levels were remarkably lower in HPV-positive compared to HPV-negative cases (P=0.01). Our data suggest that upregulated STAT1 and interferon signals by HPV16 E6 and E7 genes may play a major role in the relatively favorable prognosis for HPV-positive oropharyngeal squamous cell carcinoma cases with non-disruptive p53 mutations. PMID:23708675

Oh, Ji-Eun; Kim, Jeong-Oh; Shin, Jung-Young; Zhang, Xiang-Hua; Won, Hye-Sung; Chun, Sang-Hoon; Jung, Chan-Kwon; Park, Won-Sang; Nam, Suk-Woo; Eun, Jung-Woo; Kang, Jin-Hyoung

2013-08-01

135

Elucidating Molecular Interactions of Natural Inhibitors with HPV-16 E6 Oncoprotein through Docking Analysis  

PubMed Central

Human papillomavirus (HPV) infection is the leading cause of cancer mortality among women worldwide. The life-threatening infection caused by HPV demands the need for designing anticancerous drugs. In the recent years, different compounds from natural origins, such as carrageenan, curcumin, epigallocatechin gallate, indole-3-carbinol, jaceosidin, and withaferin, have been used as a hopeful source of anticancer therapy. These compounds have been shown to suppress HPV infection by different researchers. In the present study, we explored these natural inhibitors against E6 oncoprotein of high-risk HPV-16, which is known to inactivate the p53 tumor suppressor protein. A robust homology model of HPV-16 E6 was built to anticipate the interaction mechanism of E6 oncoprotein with natural inhibitory molecules using a structure-based drug designing approach. Docking analysis showed the interaction of these natural compounds with the p53-binding site of E6 protein residues 113-122 (CQKPLCPEEK) and helped the restoration of p53 functioning. Docking analysis, besides helping in silico validation of natural compounds, also helps understand molecular mechanisms of protein-ligand interactions. PMID:25031569

Jena, Lingaraja; Galande, Sneha; Daf, Sangeeta; Mohod, Kanchan; Varma, Ashok K.

2014-01-01

136

Acetylation of the c-MYC oncoprotein is required for cooperation with the HTLV-1 p30(II) accessory protein and the induction of oncogenic cellular transformation by p30(II)/c-MYC.  

PubMed

The human T-cell leukemia retrovirus type-1 (HTLV-1) p30(II) protein is a multifunctional latency-maintenance factor that negatively regulates viral gene expression and deregulates host signaling pathways involved in aberrant T-cell growth and proliferation. We have previously demonstrated that p30(II) interacts with the c-MYC oncoprotein and enhances c-MYC-dependent transcriptional and oncogenic functions. However, the molecular and biochemical events that mediate the cooperation between p30(II) and c-MYC remain to be completely understood. Herein we demonstrate that p30(II) induces lysine-acetylation of the c-MYC oncoprotein. Acetylation-defective c-MYC Lys?Arg substitution mutants are impaired for oncogenic transformation with p30(II) in c-myc(-/-) HO15.19 fibroblasts. Using dual-chromatin-immunoprecipitations (dual-ChIPs), we further demonstrate that p30(II) is present in c-MYC-containing nucleoprotein complexes in HTLV-1-transformed HuT-102 T-lymphocytes. Moreover, p30(II) inhibits apoptosis in proliferating cells expressing c-MYC under conditions of genotoxic stress. These findings suggest that c-MYC-acetylation is required for the cooperation between p30(II)/c-MYC which could promote proviral replication and contribute to HTLV-1-induced carcinogenesis. PMID:25569455

Romeo, Megan M; Ko, Bookyung; Kim, Janice; Brady, Rebecca; Heatley, Hayley C; He, Jeffrey; Harrod, Carolyn K; Barnett, Braden; Ratner, Lee; Lairmore, Michael D; Martinez, Ernest; Lüscher, Bernhard; Robson, Craig N; Henriksson, Marie; Harrod, Robert

2015-02-01

137

Intracellular scFvs against the viral E6 oncoprotein provoke apoptosis in human papillomavirus-positive cancer cells  

E-print Network

Intracellular scFvs against the viral E6 oncoprotein provoke apoptosis in human papillomavirus : 10.1016/j.bbrc.2007.07.040 #12;ABSTRACT The E6 protein of Human papillomavirus type 16 (16E6 infection with high-risk human papillomaviruses (HPVs) [1]. Epidemiological studies have demonstrated

Paris-Sud XI, Université de

138

Oct4 Is Required ?E7.5 for Proliferation in the Primitive Streak  

PubMed Central

Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ?E6.0–E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ?E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ?E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ?E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype. PMID:24244203

DeVeale, Brian; Brokhman, Irina; Mohseni, Paria; Babak, Tomas; Yoon, Charles; Lin, Anthony; Onishi, Kento; Tomilin, Alexey; Pevny, Larysa; Zandstra, Peter W.; Nagy, Andras; van der Kooy, Derek

2013-01-01

139

Oct4 is required ~E7.5 for proliferation in the primitive streak.  

PubMed

Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ~E6.0-E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ~E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ~E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ?E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype. PMID:24244203

DeVeale, Brian; Brokhman, Irina; Mohseni, Paria; Babak, Tomas; Yoon, Charles; Lin, Anthony; Onishi, Kento; Tomilin, Alexey; Pevny, Larysa; Zandstra, Peter W; Nagy, Andras; van der Kooy, Derek

2013-11-01

140

Polo-like kinase 4 transcription is activated via CRE and NRF1 elements, repressed by DREAM through CDE/CHR sites and deregulated by HPV E7 protein  

PubMed Central

Infection by oncogenic viruses is a frequent cause for tumor formation as observed in cervical cancer. Viral oncoproteins cause inactivation of p53 function and false transcriptional regulation of central cell cycle genes. Here we analyze the regulation of Plk4, serving as an example of many cell cycle- and p53-regulated genes. Cell cycle genes are often repressed via CDE and CHR elements in their promoters and activated by NF-Y binding to CCAAT-boxes. In contrast, general activation of Plk4 depends on NRF1 and CRE sites. Bioinformatic analyses imply that NRF1 and CRE are central elements of the transcriptional network controlling cell cycle genes. We identify CDE and CHR sites in the Plk4 promoter, which are necessary for binding of the DREAM (DP, RB-like, E2F4 and MuvB) complex and for mediating repression in G0/G1. When cells progress to G2 and mitosis, DREAM is replaced by the MMB (Myb-MuvB) complex that only requires the CHR element for binding. Plk4 expression is downregulated by the p53-p21WAF1/CIP1-DREAM signaling pathway through the CDE and CHR sites. Cell cycle- and p53-dependent repression is abrogated by HPV E7 oncoprotein. Together with genome-wide analyses our results imply that many cell cycle genes upregulated in tumors by viral infection are bound by DREAM through CDE/CHR sites. PMID:24071582

Fischer, Martin; Quaas, Marianne; Wintsche, Axel; Müller, Gerd A.; Engeland, Kurt

2014-01-01

141

Polo-like kinase 4 transcription is activated via CRE and NRF1 elements, repressed by DREAM through CDE/CHR sites and deregulated by HPV E7 protein.  

PubMed

Infection by oncogenic viruses is a frequent cause for tumor formation as observed in cervical cancer. Viral oncoproteins cause inactivation of p53 function and false transcriptional regulation of central cell cycle genes. Here we analyze the regulation of Plk4, serving as an example of many cell cycle- and p53-regulated genes. Cell cycle genes are often repressed via CDE and CHR elements in their promoters and activated by NF-Y binding to CCAAT-boxes. In contrast, general activation of Plk4 depends on NRF1 and CRE sites. Bioinformatic analyses imply that NRF1 and CRE are central elements of the transcriptional network controlling cell cycle genes. We identify CDE and CHR sites in the Plk4 promoter, which are necessary for binding of the DREAM (DP, RB-like, E2F4 and MuvB) complex and for mediating repression in G0/G1. When cells progress to G2 and mitosis, DREAM is replaced by the MMB (Myb-MuvB) complex that only requires the CHR element for binding. Plk4 expression is downregulated by the p53-p21(WAF1/CIP1)-DREAM signaling pathway through the CDE and CHR sites. Cell cycle- and p53-dependent repression is abrogated by HPV E7 oncoprotein. Together with genome-wide analyses our results imply that many cell cycle genes upregulated in tumors by viral infection are bound by DREAM through CDE/CHR sites. PMID:24071582

Fischer, Martin; Quaas, Marianne; Wintsche, Axel; Müller, Gerd A; Engeland, Kurt

2014-01-01

142

Histone deacetylase inhibitor-induced sensitization to TNFalpha/TRAIL-mediated apoptosis in cervical carcinoma cells is dependent on HPV oncogene expression.  

PubMed

Histone-deacetylase (HDAC) inhibitors (HDACi) can block proliferation and induce intrinsic apoptosis in human papillomavirus (HPV)-positive cervical carcinoma cells, independently of copy number and integration locus of the viral DNA. Using HPV18-positive HeLa cells as model systems, we provide evidence that HDAC inhibition leads to transcriptional suppression of c-FLIP, which negatively regulates extrinsic apoptosis by preventing the recruitment of caspase-8 to the death-inducing signaling complex. Consequently, HDACi pretreatment renders cervical cancer cells sensitive to TNFalpha and TRAIL-induced apoptosis. Already 5-hr incubation with TNFalpha or TRAIL was sufficient to eradicate more than 40% of pretreated cells, which are normally completely refractory against respective death-ligands alone even under long-term incubation. Ectopic expression of either short or long splicing variant of c-FLIP, c-FLIP(s) and c-FLIP(L), abrogates sensitization. Notably, combined HDACi/death ligand treatment did not result in eradication of HPV-negative cells, despite the fact that both c-FLIP isoforms were also downregulated. However, knocking down HPV18 E6/E7 transcription by siRNA prevents HDACi/death-ligand mediated apoptosis, indicating that continued viral oncogene expression favors sensitization. Here, the viral oncoprotein E7 seems to play a functional role, since only HPV16 E7-immortalized human keratinocytes underwent significant apoptosis on HDACi/TNFalpha treatment, whereas keratinocytes expressing only HPV16 E6 or primary keratinocytes were refractory under the same experimental conditions. Taken together, HDACi can be considered as an alternative therapeutic option in the treatment of premalignant and malignant lesions. PMID:20087862

Darvas, Katalin; Rosenberger, Simone; Brenner, Dirk; Fritsch, Cornelius; Gmelin, Nadine; Krammer, Peter H; Rösl, Frank

2010-09-01

143

Oncoprotein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD or 55 kD as determined by reducing SDS-PAGE, having serine and theonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

2001-02-27

144

An RNA Aptamer Targets the PDZ-Binding Motif of the HPV16 E6 Oncoprotein  

PubMed Central

Human papillomavirus 16 (HPV16) is a high-risk DNA tumour virus which is the primary causative agent of cervical cancer. Cell transformation arises from deregulated expression of the E6 and E7 oncogenes. E6 has been shown to bind a number of cellular proteins, including p53 and proteins containing a PDZ domain. This study reports the first RNA aptamers to E6. These have been employed as molecular tools to further investigate E6-p53 and E6-PDZ interactions. This study is focussed on two aptamers (termed F2 and F4) which induced apoptosis in cells derived from an HPV16-transformed cervical carcinoma. The molecules were able to inhibit the interaction between E6 and PDZ1 from Magi1, with F2 being the most effective inhibitor. Neither of the aptamers inhibited E6-p53 interaction or p53 degradation. This study shows the specificity of this approach and highlights the potential benefits of the E6 aptamers as potential therapeutic or diagnostic agents in the future. PMID:25062098

Belyaeva, Tamara A.; Nicol, Clare; Cesur, Özlem; Travé, Gilles; Blair, George Eric; Stonehouse, Nicola J.

2014-01-01

145

Differences in structural elements of Bcr-Abl oncoprotein isoforms in Chronic Myelogenous Leukemia  

PubMed Central

in silico modeling, using Psipred and ExPASy servers was employed to determine the structural elements of Bcr-Abl oncoprotein (p210BCR-ABL) isoforms, b2a2 and b3a2, expressed in Chronic Myelogenous Leukemia (CML). Both these proteins are tyrosine kinases having masses of 210-kDa and differing only by 25 amino acids coded by the b3 exonand an amino acidsubstitution (Glu903Asp). The secondary structure elements of the two proteins show differences in five ?-helices and nine ?-strands which relates to differences in the SH3, SH2, SH1 and DNA-binding domains. These differences can result in different roles played by the two isoforms in mediating signal transduction during the course of CML. PMID:24748748

Hai, Abdul; Kizilbash, Nadeem A; Zaidi, Syeda Huma H; Alruwaili, Jamal; Shahzad, Khuram

2014-01-01

146

Therapeutic DNA vaccination against colorectal cancer by targeting the MYB oncoprotein  

PubMed Central

Cancers can be addicted to continued and relatively high expression of nuclear oncoproteins. This is evident in colorectal cancer (CRC) where the oncoprotein and transcription factor MYB is over expressed and essential to continued proliferation and tumour cell survival. Historically, targeting transcription factors in the context of cancer has been very challenging. Nevertheless, we formulated a DNA vaccine to generate a MYB-specific immune response in the belief MYB peptides might be aberrantly presented on the cell surface of CRC cells. MYB, like many tumour antigens, is weakly immunogenic as it is a ‘self' antigen and is subject to tolerance. To break tolerance, a fusion vaccine was generated comprising a full-length MYB complementary DNA (cDNA) flanked by two potent CD4-epitopes derived from tetanus toxoid. Vaccination was achieved against tumours initiated by two distinct highly aggressive, syngeneic cancer cell lines (CT26 and MC38) that express MYB. This was done in BALB/c and C57BL/6 mouse strains respectively. We introduced multiple inactivating mutations into the oncogene sequence for safety and sub-cloned the cDNA into a Food and Drug Administration (FDA)-compliant vector. We used low dose cyclophosphamide (CY) to overcome T-regulatory cell immune suppression, and anti-program cell death receptor 1 (anti-PD-1) antibodies to block T-cell exhaustion. Anti-PD-1 administered alone slightly delayed tumour growth in MC38 and more effectively in CT26 bearing mice, while CY treatment alone did not. We found that therapeutic vaccination elicits protection when MC38 tumour burden is low, mounts tumour-specific cell killing and affords enhanced protection when MC38 and CT26 tumour burden is higher but only in combination with anti-PD-1 antibody or low dose CY, respectively. PMID:25671128

Cross, Ryan S; Malaterre, Jordane; Davenport, Alexander J; Carpinteri, Sandra; Anderson, Robin L; Darcy, Phillip K; Ramsay, Robert G

2015-01-01

147

Therapeutic DNA vaccination against colorectal cancer by targeting the MYB oncoprotein.  

PubMed

Cancers can be addicted to continued and relatively high expression of nuclear oncoproteins. This is evident in colorectal cancer (CRC) where the oncoprotein and transcription factor MYB is over expressed and essential to continued proliferation and tumour cell survival. Historically, targeting transcription factors in the context of cancer has been very challenging. Nevertheless, we formulated a DNA vaccine to generate a MYB-specific immune response in the belief MYB peptides might be aberrantly presented on the cell surface of CRC cells. MYB, like many tumour antigens, is weakly immunogenic as it is a 'self' antigen and is subject to tolerance. To break tolerance, a fusion vaccine was generated comprising a full-length MYB complementary DNA (cDNA) flanked by two potent CD4-epitopes derived from tetanus toxoid. Vaccination was achieved against tumours initiated by two distinct highly aggressive, syngeneic cancer cell lines (CT26 and MC38) that express MYB. This was done in BALB/c and C57BL/6 mouse strains respectively. We introduced multiple inactivating mutations into the oncogene sequence for safety and sub-cloned the cDNA into a Food and Drug Administration (FDA)-compliant vector. We used low dose cyclophosphamide (CY) to overcome T-regulatory cell immune suppression, and anti-program cell death receptor 1 (anti-PD-1) antibodies to block T-cell exhaustion. Anti-PD-1 administered alone slightly delayed tumour growth in MC38 and more effectively in CT26 bearing mice, while CY treatment alone did not. We found that therapeutic vaccination elicits protection when MC38 tumour burden is low, mounts tumour-specific cell killing and affords enhanced protection when MC38 and CT26 tumour burden is higher but only in combination with anti-PD-1 antibody or low dose CY, respectively. PMID:25671128

Cross, Ryan S; Malaterre, Jordane; Davenport, Alexander J; Carpinteri, Sandra; Anderson, Robin L; Darcy, Phillip K; Ramsay, Robert G

2015-01-01

148

Receptor Protein-tyrosine Phosphatase ? Regulates Focal Adhesion Kinase Phosphorylation and ErbB2 Oncoprotein-mediated Mammary Epithelial Cell Motility*  

PubMed Central

We investigated the role of protein-tyrosine phosphatase ? (PTP?) in regulating signaling by the ErbB2 oncoprotein in mammary epithelial cells. Using this model, we demonstrated that activation of ErbB2 led to the transient inactivation of PTP?, suggesting that attenuation of PTP? activity may contribute to enhanced ErbB2 signaling. Furthermore, RNAi-induced suppression of PTP? led to increased cell migration in an ErbB2-dependent manner. The ability of ErbB2 to increase cell motility in the absence of PTP? was characterized by prolonged interaction of GRB7 with ErbB2 and increased association of ErbB2 with a ?1-integrin-rich complex, which depended on GRB7-SH2 domain interactions. Finally, suppression of PTP? resulted in increased phosphorylation of focal adhesion kinase on Tyr-407, which induced the recruitment of vinculin and the formation of a novel focal adhesion kinase complex in response to ErbB2 activation in mammary epithelial cells. Collectively, these results reveal a new role for PTP? in the regulation of motility of mammary epithelial cells in response to ErbB2 activation. PMID:24217252

Boivin, Benoit; Chaudhary, Fauzia; Dickinson, Bryan C.; Haque, Aftabul; Pero, Stephanie C.; Chang, Christopher J.; Tonks, Nicholas K.

2013-01-01

149

Supersymmetric E$_{7(7)}$ Exceptional Field Theory  

E-print Network

We give the supersymmetric extension of exceptional field theory for E$_{7(7)}$, which is based on a $(4+56)$-dimensional generalized spacetime subject to a covariant constraint. The fermions are tensors under the local Lorentz group ${\\rm SO}(1,3)\\times {\\rm SU}(8)$ and transform as scalar densities under the E$_{7(7)}$ (internal) generalized diffeomorphisms. The supersymmetry transformations are manifestly covariant under these symmetries and close, in particular, into the generalized diffeomorphisms of the 56-dimensional space. We give the fermionic field equations and prove supersymmetric invariance. We establish the consistency of these results with the recently constructed generalized geometric formulation of $D=11$ supergravity.

Hadi Godazgar; Mahdi Godazgar; Olaf Hohm; Hermann Nicolai; Henning Samtleben

2014-09-05

150

Supersymmetric E7(7) exceptional field theory  

NASA Astrophysics Data System (ADS)

We give the supersymmetric extension of exceptional field theory for E7(7), which is based on a (4 + 56)-dimensional generalized spacetime subject to a covariant constraint. The fermions are tensors under the local Lorentz group SO(1, 3) × SU(8) and transform as scalar densities under the E7(7) (internal) generalized diffeomorphisms. The supersymmetry transformations are manifestly covariant under these symmetries and close, in particular, into the generalized diffeomorphisms of the 56-dimensional space. We give the fermionic field equations and prove supersymmetric invariance. We establish the consistency of these results with the recently constructed generalized geometric formulation of D = 11 supergravity.

Godazgar, Hadi; Godazgar, Mahdi; Hohm, Olaf; Nicolai, Hermann; Samtleben, Henning

2014-09-01

151

Both Normal and Transforming PCPH Proteins Have Guanosine Diphosphatase Activity But Only the Oncoprotein Cooperates with Ras in Activating Extracellular Signal-regulated Kinase ERK11  

Microsoft Academic Search

Previous reports from our laboratory described the activation of the PCPH gene into the PCPH oncogene (mt-PCPH, reported previously as Cph) by a single point mutational deletion. As a consequence, the mt- PCPH oncoprotein is a truncated form of the normal PCPH protein. Although both proteins have ribonucleotide diphosphate-binding activity, only mt-PCPH acted synergistically with a human H-Ras oncoprotein to

Juan A. Recio; J. Guillermo Paez; Baishali Maskeri; Mark Loveland; Juan A. Velasco; Vicente Notario

2000-01-01

152

Bcl2 Oncoprotein Blocks Chemotherapy-Induced Apoptosis in a Human Leukemia Cell Line  

Microsoft Academic Search

HE bcl-2 gene was initially discovered by virtue of its T involvement in t( 14; 181 (q32;q21) chromosomal translocations that are found in the majority of non-Hodg- kin's lymphomas (NHLs).' This gene encodes a 26-Kd in- tegral membrane protein that appears to reside at least in part in mitochondria, and that promotes the survival of sev- eral types of hematolymphoid

Toshiyuki Miyashita; John C. Reed

1993-01-01

153

The proto-oncoprotein SYT (SS18) controls ATP release and regulates cyst formation by polarized MDCK cells  

Microsoft Academic Search

The SYT proto-oncoprotein (also known as SS18) is a gene expression regulator conserved across species. Although its biological function is still unknown, the importance of SYT as a housekeeping protein is illustrated by the lethal phenotype of SYT-null embryos. Notably, SYT is a component of the synovial sarcoma-associated translocation product, the SYT–SSX oncogene. SYT was previously reported as a mediator

Manesh Chittezhath; Andrea L. Frump; Jerome Jourquin; Nichole Lobdell; Josiane E. Eid

2008-01-01

154

Control of Microtubule Dynamics by Oncoprotein 18: Dissection of the Regulatory Role of Multisite Phosphorylation during Mitosis  

Microsoft Academic Search

Oncoprotein 18 (Op18; also termed p19, 19K, metablastin, stathmin, and prosolin) is a conserved protein that regulates microtubule (MT) dynamics. Op18 is multisite phosphorylated on four Ser residues during mitosis; two of these Ser residues, Ser-25 and Ser-38, are targets for cyclin-dependent protein kinases (CDKs), and the other two Ser residues, Ser-16 and Ser-63, are targets for an unidentified protein

NIKLAS LARSSON; ULRICA MARKLUND; HELENA MELANDER GRADIN; GORAN BRATTSAND; MARTIN GULLBERG

1997-01-01

155

Prediction of homologous binding sites on RB and p107 common for viral oncoproteins and cellular ligands.  

PubMed

Hydropathic anticomplementarity of amino acids specifies that peptides translated from complementary DNA strands may acquire amphiphilic conformations and bind to each other. This concept has been coined 'Molecular Recognition Theory' (MRT) or 'complementary peptide theory'. Inactivation of retinoblastoma protein (RB), a tumor suppressor gene product, has been shown to be involved in the pathogenesis of many tumors and to be due to either mutation of the RB gene, hyperphosphorylation or complex formation with viral oncoproteins. The viral oncoproteins share a common RB binding motif with cellular ligands. The exact site on RB associating with this common RB binding motif of viral oncoproteins and cellular ligands has not been identified yet. This study is the first to predict putative binding sites on RB and p107, a cellular protein with RB sequence homology, respectively, by using the hydropathic complementarity approach. These sites are residues 649-654 of RB and 657-662 of p107. Moreover, this paper proposes a structure for a potential antineoplastic agent based on the amino acid sequence of the predicted RB binding site. The data presented herein should have important implications both for the understanding of cancer pathophysiology and for the drug design of antineoplastic compounds. PMID:1339480

Wendtner, C M; Radulescu, R T

1992-12-01

156

The Human T-Cell Leukemia Virus Type 1 Oncoprotein Tax Controls Forkhead Box O4 Activity through Degradation by the Proteasome?  

PubMed Central

Activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway by the viral Tax oncoprotein plays a pivotal role in clonal expansion of human T-cell leukemia virus type 1 (HTLV-1)-infected cells. As the Forkhead box O (FoxO) tumor suppressors act as downstream effectors of PI3K/Akt, they represent good candidate targets whose dysregulation by Tax might be involved in HTLV-1-mediated activation and transformation of infected cells. In this report, we provide evidence showing that Tax induces a dose-dependent degradation of FoxO4 by the ubiquitin-proteasome pathway. Consistent with that, we demonstrate that Tax expression increases the interaction between FoxO4 and Mdm2 E3 ligase, leading to a strong FoxO4 polyubiquitination. These processes require the phosphorylation of FoxO4 by Akt, since a mutant of FoxO4 with mutations on its three Akt phosphorylation sites appears to be resistant to Tax-mediated degradation and ubiquitination. In addition, we show that Tax expression is associated with degradation and phosphorylation of endogenous FoxO4 in Jurkat T cells. Finally, we demonstrate that Tax represses FoxO4 transcriptional activity. Our study demonstrates that Tax can control FoxO4 protein stability and transcriptional activity and provides new insight into the subversion of cell signaling pathways during HTLV-1 infection. PMID:21525355

Oteiza, Alexandra; Mechti, Nadir

2011-01-01

157

p53Independent Abrogation of a Postmitotic Checkpoint Contributes to Human Papillomavirus E6Induced Polyploidy  

Microsoft Academic Search

Polyploidy is often an early event during cervical carcinogen- esis, and it predisposes cells to aneuploidy, which is thought to play a causal role in tumorigenesis. Cervical and anogenital cancers are induced by the high-risk types of human papillo- mavirus (HPV). The HPV E6 oncoprotein induces polyploidy in human keratinocytes, yet the mechanism is not known. It was believed that

Yingwang Liu; Susan A. Heilman; Diego Illanes; Greenfield Sluder

158

Toll like receptor agonists augment HPV 11 E7-specific T cell responses by modulating monocyte-derived dendritic cells.  

PubMed

Impaired local cellular immunity is one of the mechanisms responsible for condyloma acuminatum (CA) recurrence. The activation of dendritic cells (DCs) is important in vaccine development. We investigated the effect of different toll like receptor (TLR) agonists including LPS (TLR4 agonist), polyinosinic acid-polycytidylic acid (PIC, TLR3 agonist), CpG oligonucleotide (TLR9 agonist), and imiquimod (TLR7 agonist) on human monocyte-derived dendritic cells (mdDCs) loading of human papillomavirus (HPV) type 11 E7 epitope. As a result, we found that mdDCs loading HLA-A*0201-restricted HPV 11 E7 CTL epitope peptide could respond to the TLR agonists, especially LPS and PIC. This was characterized by an enhanced expression of CD40, CD80, CD86, CD83 and HLA-DR, and a high level of IL-12 production. TLR agonists, especially PIC, enhanced the ability of E7-loaded mdDCs to induce IFN-gamma-secretion CD4(+) naïve T cells. Moreover, E7-loaded mdDCs exposed to TLR agonists augmented autologous T cell responses including effector cytokines production and specific cytotoxic T lymphocyte (CTL) responses. In addition, the inhibitory effect of IL-10 on mdDCs maturation could be partially restored by LPS, PIC or imiquimod. Taken together, these results demonstrate that TLR agonists promoted the maturation of E7-loaded mdDCs and their ability to induce T help type 1 polarization and augment E7-specific T cell responses. These data also indicated that TLR3/4 agonists might be effective adjuvants of mdDC-based vaccines against CA. PMID:19578865

Chen, Xian-Zhen; Mao, Xiao-Hong; Zhu, Ke-Jian; Jin, Na; Ye, Jun; Cen, Jian-Ping; Zhou, Qiang; Cheng, Hao

2010-01-01

159

ch-IAP1, a member of the inhibitor-of-apoptosis protein family, is a mediator of the antiapoptotic activity of the v-Rel oncoprotein.  

PubMed Central

The oncoprotein v-Rel, a member of the Rel/NF-kappaB family of transcription factors, induces neoplasias and inhibits apoptosis. To identify differentially regulated cellular genes and to evaluate their relevance to transformation and apoptosis in v-Rel-transformed cells, mRNA differential display has been used. One of the recovered cDNAs corresponds to a gene that was highly expressed in v-Rel-transformed fibroblasts. Analysis of the isolated full-length cDNA of a chicken inhibitor-of-apoptosis protein (ch-IAP1) revealed that it encodes a 68-kDa protein that is highly homologous to members of the IAP family, such as human c-LAP1. Like other IAPs, ch-IAP1 contains the N-terminal baculovirus IAP repeats and C-terminal RING finger motifs. Northern blot analysis identified a 3.3-kb ch-IAP1 transcript expressed at relatively high levels in the spleen, thymus, bursa, intestine, and lungs. Expression of v-Rel in fibroblasts, a B-cell line, and spleen cells up-regulated the expression of ch-IAP1. In contrast, ch-IAP1 expression levels were low in chicken cell lines transformed by several other unrelated tumor viruses. ch-IAP1 was expressed predominantly in the cytoplasm of the v-Rel-transformed cells. ch-IAP1 suppressed mammalian cell apoptosis induced by the overexpression of the interleukin-1-converting enzyme. Expression of exogenous ch-IAP1 in temperature-sensitive v-Rel transformed spleen cells inhibited apoptosis of these cells at the nonpermissive temperature. Collectively, these results suggest that ch-IAP1 is induced during the v-Rel-mediated transformation process and functions as a suppressor of apoptosis in v-Rel-transformed cells. PMID:9372964

You, M; Ku, P T; Hrdlicková, R; Bose, H R

1997-01-01

160

Cross-talk between phosphorylation and SUMOylation regulates transforming activities of an adenoviral oncoprotein.  

PubMed

Since the discovery of post-translational modification (PTM) by the small ubiquitin-related modifiers (SUMOs), a multitude of proteins have been described to be reversibly modified, resulting in the alteration of several cellular pathways. Interestingly, various pathogens gain access to this modification system, although the molecular mechanisms and functional consequences are barely understood. We show here that the adenoviral oncoprotein E1B-55K is a substrate of the SUMO conjugation system, which is directly linked to its C-terminal phosphorylation. This regulative connection is indispensable for modulation of the tumor suppressor p53/chromatin-remodeling factor Daxx by E1B-55K and, consequently, its oncogenic potential in primary mammalian cells. In virus infection, E1B-55K PTMs are necessary for localization to viral transcription/replication sites. Furthermore, we identify the E2 enzyme Ubc9 as an interaction partner of E1B-55K, providing a possible molecular explanation for SUMO-dependent modulation of cellular target proteins. In conclusion, these results for the first time provide evidence how E1B-55K PTMs are regulated and subsequently facilitate exploitation of the host cell SUMOylation machinery. PMID:22614022

Wimmer, P; Blanchette, P; Schreiner, S; Ching, W; Groitl, P; Berscheminski, J; Branton, P E; Will, H; Dobner, T

2013-03-28

161

HBXIP, cellular target of hepatitis B virus oncoprotein, is a regulator of centrosome dynamics and cytokinesis.  

PubMed

Hepatitis B virus accounts for more than 1 million cancer deaths annually, but the mechanism by which this virus promotes hepatocellular carcinoma remains unclear. The hepatitis B virus genome encodes an oncoprotein, HBx, which binds various cellular proteins including HBXIP. We show here that HBXIP is a regulator of centrosome duplication, required for bipolar spindle formation in HeLa human carcinoma cells and primary mouse embryonic fibroblast cells. We found that most cells deficient in HBXIP arrest in prometaphase with monopolar spindles whereas HBXIP overexpression causes tripolar or multipolar spindles due to excessive centrosome replication. Additionally, a defect in cytokinesis was seen in HBXIP-deficient HeLa cells, with most cells failing to complete division and succumbing eventually to apoptosis. Expression of viral HBx in HeLa cells mimicked the effects of HBXIP overexpression, causing excessive centrosome replication, resulting in tripolar and multipolar spindles and defective cytokinesis. Immunolocalization and fluorescent protein tagging experiments showed that HBXIP associates with microtubules of dividing cells and colocalizes with HBx on centrosomes. Thus, viral HBx and its cellular target HBXIP regulate centrosome dynamics and cytokinesis affecting genetic stability. In vivo experiments using antisense oligonucleotides targeting HBXIP in a mouse model of liver regeneration showed a requirement for HBXIP for growth and survival of replicating hepatocytes. Thus, HBXIP is a critical regulator of hepatocyte cell growth in vivo, making it a strong candidate for explaining the tumorigenic actions of viral HBx. PMID:16982752

Fujii, Ryoji; Zhu, Changjun; Wen, Yunfei; Marusawa, Hiroyuki; Bailly-Maitre, Beatrice; Matsuzawa, Shu-ichi; Zhang, Hong; Kim, Youngsoo; Bennett, C Frank; Jiang, Wei; Reed, John C

2006-09-15

162

Expression of activated STAT5 in neoplastic mast cells in systemic mastocytosis: subcellular distribution and role of the transforming oncoprotein KIT D816V.  

PubMed

Recent data suggest that the signal transducer and activator of transcription (STAT)5 contributes to differentiation and growth of mast cells. It has also been described that constitutively phosphorylated STAT5 (pSTAT5) plays a pro-oncogenic role in various myeloid neoplasms. We examined the expression of pSTAT5 in neoplastic mast cells in systemic mastocytosis and asked whether the disease-related oncoprotein KIT D816V is involved in STAT5 activation. As assessed by immunohistochemistry using the anti-pSTAT5 antibody AX1, neoplastic mast cells were found to display pSTAT5 in all SM patients examined (n = 40). Expression of pSTAT5 was also demonstrable in the KIT D816V-positive mast cell leukemia cell line HMC-1. Using various staining-protocols, pSTAT5 was found to be located in both the cytoplasmic and nuclear compartment of mast cells. To define the functional role of KIT D816V in STAT5-activation, Ba/F3 cells with doxycycline-inducible expression of KIT D816V were used. In these cells, induction of KIT D816V resulted in an increased expression of pSTAT5 without substantial increase in total STAT5. Moreover, the KIT D816V-targeting kinase-inhibitor PKC412 was found to counteract expression of pSTAT5 in HMC-1 cells as well as doxycycline-induced expression of pSTAT5 in Ba/F3 cells. Finally, a dominant negative STAT5-construct was found to inhibit growth of HMC-1 cells. Together, our data show that neoplastic mast cells express cytoplasmic and nuclear pSTAT5, that KIT D816V promotes STAT5-activation, and that STAT5-activation contributes to growth of neoplastic mast cells. PMID:19893034

Baumgartner, Christian; Cerny-Reiterer, Sabine; Sonneck, Karoline; Mayerhofer, Matthias; Gleixner, Karoline V; Fritz, Richard; Kerenyi, Marc; Boudot, Cedric; Gouilleux, Fabrice; Kornfeld, Jan-Wilhelm; Sillaber, Christian; Moriggl, Richard; Valent, Peter

2009-12-01

163

Exceptional field theory. II. E7(7)  

NASA Astrophysics Data System (ADS)

We introduce the exceptional field theory for the group E7(7), based on a (4+56)-dimensional spacetime subject to a covariant section condition. The "internal" generalized diffeomorphisms of the coordinates in the fundamental representation of E7(7) are governed by a covariant "E-bracket," which is gauged by 56 vector fields. We construct the complete and unique set of field equations that is gauge invariant under generalized diffeomorphisms in the internal and external coordinates. Among them are featured the non-Abelian twisted self-duality equations for the 56 gauge vectors. We discuss the explicit solutions of the section condition describing the embedding of the full, untruncated 11-dimensional and type IIB supergravity, respectively. As a new feature compared to the previously constructed E6(6) formulation, some components among the 56 gauge vectors descend from the 11-dimensional dual graviton but nevertheless allow for a consistent coupling by virtue of a covariantly constrained compensating 2-form gauge field.

Hohm, Olaf; Samtleben, Henning

2014-03-01

164

Detection of the apoptosis-suppressing oncoprotein bc1-2 in hormone-refractory human prostate cancers.  

PubMed Central

The oncoprotein encoded by bc1-2 is unique because of its intracellular location (a mitochondrial membrane protein) and apparent mode of action (suppression of apoptosis). To date, this oncogene has been associated only with the development of certain forms of human B-cell lymphoma. In this report, we describe our experience with a monoclonal antibody made against a synthetic peptide for bc1-2 that can recognize the bc1-2 protein and identify cells in human prostate glands expressing this proto-oncogene with in situ immunohistochemical procedures. These procedures were utilized to survey a series of 62 human tissues to evaluate whether bc1-2 might have a role in the developing prostate gland or in prostate oncogenesis. While all primordial epithelial cells in a fetal prostate gland immunostain for bc1-2, normal and hypertrophic prostate glands of the adult show bc1-2 expression restricted to the basal cells. All epithelial cells in areas of prostatic intraepithelial neoplasia were stained by this antibody, as were most (62%) localized invasive prostatic carcinomas. In contrast, all primary prostatic carcinomas and metastases obtained from metastatic prostate cancer patients after hormone treatment (hormone-refractory tumors) stained positive for bc1-2. This study demonstrates that the oncoprotein encoded by bc1-2 can be detected at sequential stages in the natural history of human prostate cancer. Since the bc1-2 oncoprotein is known to suppress the cellular response to apoptotic stimuli, it will be important to determine whether bc1-2 expression is a factor in the development of prostate cancers and in the survival of hormone-refractory prostate cancer cells. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:7688182

Colombel, M.; Symmans, F.; Gil, S.; O'Toole, K. M.; Chopin, D.; Benson, M.; Olsson, C. A.; Korsmeyer, S.; Buttyan, R.

1993-01-01

165

Interaction of the v-Rel oncoprotein with cellular transcription factor Sp1.  

PubMed Central

We previously showed that v-Rel, the oncoprotein of the avian retrovirus Rev-T, can increase expression from promoters containing binding sites for the cellular transcription factor Sp1 in chicken embryo fibroblasts (S. Sif, A.J. Capobianco, and T.D. Gilmore, Oncogene 8:2501-2509, 1993). In those experiments, v-Rel appeared to increase the transactivating function of Sp1; that is, v-Rel stimulated transactivation by a GAL4-Sp1 protein that lacked the Sp1 DNA-binding domain. We have now shown that in vitro-synthesized v-Rel and GAL4-Sp1 form a complex that can be immunoprecipitated with either anti-Sp1 or anti-v-Rel antiserum. We have also shown that a glutathione S-transferase (GST)-Sp1 fusion protein can specifically interact with in vitro-translated v-Rel and with in vivo-synthesized v-Rel from transformed chicken spleen cells. In addition, we have found that the abilities of wild-type and two mutant forms of v-Rel to increase transactivation by Sp1 in vivo correlate with their abilities to interact with Sp1 in vitro. The sequences important for the interaction of v-Rel with Sp1 in vitro have been mapped to the first 147 amino acids of v-Rel. Other Rel proteins, such as c-Rel, RelA, p52, and p50, were also able to form a complex with Sp1 in vitro. These results suggest that v-Rel increases expression from Sp1 site-containing promoters by functionally interacting with Sp1 and that cellular Rel proteins and Sp1 are likely to interact to influence transcription from natural promoters. Images PMID:7933095

Sif, S; Gilmore, T D

1994-01-01

166

MUC1-C ONCOPROTEIN CONFERS ANDROGEN-INDEPENDENT GROWTH OF HUMAN PROSTATE CANCER CELLS  

PubMed Central

Background The mucin 1 (MUC1) heterodimeric oncoprotein is overexpressed in human prostate cancers with aggressive pathologic and clinical features. However, few insights are available regarding the functional role of MUC1 in prostate cancer. Methods Effects of MUC1-C on AR expression were determined by RT-PCR, immunoblotting and AR promoter activation. Coimmunoprecipitations, direct binding assays and chromatin immunoprecipitation (ChIP) studies were performed to assess the interaction between MUC1-C and AR. Cells were analyzed for invasion, growth in androgen-depleted medium and sensitivity to MUC1-C inhibitors. Results The present studies in androgen-dependent LNCaP and LAPC4 prostate cancer cells demonstrate that the oncogenic MUC1-C subunit suppresses AR expression. The results show that MUC1-C activates a posttranscriptional mechanism involving miR-135b-mediated downregulation of AR mRNA levels. The results further demonstrate that MUC1-C forms a complex with AR through a direct interaction between the MUC1-C cytoplasmic domain and the AR DNA-binding domain. In addition, MUC1-C associates with AR in a complex that occupies the PSA promoter. The interaction between MUC1-C and AR is associated with induction of the epithelial-mesenchymal transition (EMT) and increased invasion. MUC1-C also conferred growth in androgen-depleted medium and resistance to bicalutamide treatment. Moreover, expression of MUC1-C resulted in sensitivity to the MUC1-C inhibitor GO-203 with inhibition of growth in vitro. GO-203 treatment also inhibited growth of established tumor xenografts in nude mice. Conclusions These findings indicate that MUC1-C suppresses AR expression in prostate cancer cells and confers a more aggressive androgen-independent phenotype that is sensitive to MUC1-C inhibition. PMID:22473899

Rajabi, Hasan; Ahmad, Rehan; Jin, Caining; Joshi, Maya Datt; Guha, Minakshi; Alam, Maroof; Kharbanda, Surender; Kufe, Donald

2012-01-01

167

GeLC-MRM quantitation of mutant KRAS oncoprotein in complex biological samples  

PubMed Central

Tumor-derived mutant KRAS (v-Ki-ras-2 Kirsten rat sarcoma viral oncogene) oncoprotein is a critical driver of cancer phenotypes and a potential biomarker for many epithelial cancers. Targeted mass spectrometry analysis by multiple reaction monitoring (MRM) enables selective detection and quantitation of wild-type and mutant KRAS proteins in complex biological samples. A recently described immunoprecipitation approach (Proc. Nat. Acad. Sci. 2011, 108, 2444–2449) can be used to enrich KRAS for MRM analysis, but requires large protein inputs (2–4 mg). Here we describe sodium dodecyl sulfate-polyacrylamide gel electrophoresis-based enrichment of KRAS in a low molecular weight (20 –25 kDa) protein fraction prior to MRM analysis (GeLC-MRM). This approach reduces background proteome complexity, thus allowing mutant KRAS to be reliably quantified in low protein inputs (5–50 ?g). GeLC-MRM detected KRAS mutant variants (G12D, G13D, G12V, G12S) in a panel of cancer cell lines. GeLC-MRM-analysis of wild-type and mutant was linear with respect to protein input and showed low variability across process replicates (CV = 14%). Concomitant analysis of a peptide from the highly similar HRAS and NRAS proteins enabled correction of KRAS-targeted measurements for contributions from these other proteins. KRAS peptides were also quantified in fluid from benign pancreatic cysts and pancreatic cancers at concentrations from 0.08 – 1.1 fmol/?g protein. GeLC-MRM provides a robust, sensitive approach to quantitation of mutant proteins in complex biological samples. PMID:22671702

Halvey, Patrick J.; Ferrone, Cristina R.; Liebler, Daniel C.

2012-01-01

168

The v-Rel Oncoprotein Complexes with New Rel and RelA-Related Proteins in Transformed Cells  

Microsoft Academic Search

The v-Rel oncoprotein of the Rev-T retrovirus interacts with a number of cellular proteins in transformed chicken spleen cells including p40\\/I?B? p68c-Rel hsc70, and the p124 and p115 precursors for the p50 and p52 subunits of NF?B. Here we report that v-Rel associates with at least three other cellular proteins of 75-85 kDa in these cells, as well as with

Xiang Xu; Céline Gélinas

1995-01-01

169

Oxymatrine Downregulates HPV16E7 Expression and Inhibits Cell Proliferation in Laryngeal Squamous Cell Carcinoma Hep-2 Cells In Vitro  

PubMed Central

Objective. To investigate the possible mechanisms of oxymatrine's role in anti laryngeal squamous cell carcinoma. Methods. We examined the effects of oxymatrine on the proliferation, cell cycle phase distribution, apoptosis, and the protein and mRNA expression levels of HPV16E7 gene in laryngeal carcinoma Hep-2 cells in vitro. The HPV16E7 siRNA inhibition was also done to confirm the effect of downregulating HPV16E7 on the proliferation in Hep-2 cells. Results. Oxymatrine significantly inhibited the growth and proliferation of Hep-2 cells in a dose-dependence and time-dependence manner. Oxymatrine blocked Hep-2 cells in G0/G1 phase, resulting in an obvious accumulation of G0/G1 phase cells while decreasing S phase cells. Oxymatrine induced apoptosis of Hep-2 cells, whose apoptotic rate amounted to about 42% after treatment with 7?mg/mL oxymatrine for 72?h. Oxymatrine also downregulated the expression of HPV16E7 gene, as determined by the western blotting and reverse transcription-polymerase chain reaction analysis. Knockdown of HPV16E7 effectively inhibited the proliferation of Hep-2 cells. Conclusions. Oxymatrine inhibits the proliferation and induces apoptosis of laryngeal carcinoma Hep-2 cells, which might be mediated by a significant cell cycle arrest in G0/G1 phase and downregulation of HPV16E7 gene. Oxymatrine is considered to be a likely preventive and curative candidate for laryngeal cancer.

Ying, Xin-Jiang; Jin, Bin; Chen, Xin-Wei; Xie, Jin; Xu, Hong-Ming; Dong, Pin

2015-01-01

170

A novel MLL5 isoform that is essential to activate E6 and E7 transcription in HPV16/18-associated cervical cancers.  

PubMed

Human papillomavirus (HPV) is the primary cause of human cervical cancer. The viral proteins E6 and E7 are essential to transform noncancerous epithelial cells into cancerous carcinomas by targeting key tumor suppressors p53 and retinoblastoma (Rb) proteins, respectively, but the cellular factors involved in E6 and E7 transcription themselves are incompletely understood. In this study, we defined a novel isoform of the mixed lineage leukemia 5 gene (MLL5?) as a specific and critical regulator of E6 and E7 transcription in cervical carcinoma cells. MLL5? is present in HPV16/18-positive cells including human primary cervical carcinoma specimens. Interaction of MLL5? with the AP-1-binding site at the distal region of the HPV18 long control region led to activation of E6/E7 transcription. Conversely, RNA interference-mediated knockdown of MLL5? downregulated both E6 and E7 expression. MLL5? downregulation was sufficient to restore p53 protein levels and reduce Rb phosphorylation, thereby reactivating apoptosis and cell-cycle checkpoints. By defining this novel MLL5? isoform and its specific critical role in activating E6/E7 gene transcription in HPV16/18-induced cervical cancers, our work highlights the potential of MLL5? as a biomarker and new therapeutic target in primary HPV-induced cervical cancers. PMID:21908553

Yew, Chow Wenn; Lee, Pei; Chan, Wai Keong; Lim, Vania Kai Jun; Tay, Sun Kuie; Tan, Theresa M C; Deng, Lih-Wen

2011-11-01

171

HPV-E7 Delivered by Engineered Exosomes Elicits a Protective CD8+ T Cell-Mediated Immune Response.  

PubMed

We developed an innovative strategy to induce a cytotoxic T cell (CTL) immune response against protein antigens of choice. It relies on the production of exosomes, i.e., nanovesicles spontaneously released by all cell types. We engineered the upload of huge amounts of protein antigens upon fusion with an anchoring protein (i.e., HIV-1 Nefmut), which is an inactive protein incorporating in exosomes at high levels also when fused with foreign proteins. We compared the immunogenicity of engineered exosomes uploading human papillomavirus (HPV)-E7 with that of lentiviral virus-like particles (VLPs) incorporating equivalent amounts of the same antigen. These exosomes, whose limiting membrane was decorated with VSV-G, i.e., an envelope protein inducing pH-dependent endosomal fusion, proved to be as immunogenic as the cognate VLPs. It is noteworthy that the immunogenicity of the engineered exosomes remained unaltered in the absence of VSV-G. Most important, we provide evidence that the inoculation in mouse of exosomes uploading HPV-E7 induces production of anti-HPV E7 CTLs, blocks the growth of syngeneic tumor cells inoculated after immunization, and controls the development of tumor cells inoculated before the exosome challenge. These results represent the proof-of-concept about both feasibility and efficacy of the Nefmut-based exosome platform for the induction of CD8+ T cell immunity. PMID:25760140

Bonito, Paola Di; Ridolfi, Barbara; Columba-Cabezas, Sandra; Giovannelli, Andrea; Chiozzini, Chiara; Manfredi, Francesco; Anticoli, Simona; Arenaccio, Claudia; Federico, Maurizio

2015-01-01

172

42 CFR 52e.7 - What are the terms and conditions of awards?  

Code of Federal Regulations, 2011 CFR

...7 Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...

2011-10-01

173

42 CFR 52e.7 - What are the terms and conditions of awards?  

Code of Federal Regulations, 2010 CFR

...7 Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...

2010-10-01

174

42 CFR 52e.7 - What are the terms and conditions of awards?  

Code of Federal Regulations, 2013 CFR

...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...

2013-10-01

175

42 CFR 52e.7 - What are the terms and conditions of awards?  

Code of Federal Regulations, 2014 CFR

...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...

2014-10-01

176

42 CFR 52e.7 - What are the terms and conditions of awards?  

Code of Federal Regulations, 2012 CFR

...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...

2012-10-01

177

Lysyl Oxidase Is Downregulated by the EWS/FLI1 Oncoprotein and Its Propeptide Domain Displays Tumor Supressor Activities in Ewing Sarcoma Cells  

PubMed Central

Ewing sarcoma is the second most common bone malignancy in children and young adults. It is driven by oncogenic fusion proteins (i.e. EWS/FLI1) acting as aberrant transcription factors that upregulate and downregulate target genes, leading to cellular transformation. Thus, identificating these target genes and understanding their contribution to Ewing sarcoma tumorigenesis are key for the development of new therapeutic strategies. In this study we show that lysyl oxidase (LOX), an enzyme involved in maintaining structural integrity of the extracellular matrix, is downregulated by the EWS/FLI1 oncoprotein and in consequence it is not expressed in Ewing sarcoma cells and primary tumors. Using a doxycycline inducible system to restore LOX expression in an Ewing sarcoma derived cell line, we showed that LOX displays tumor suppressor activities. Interestingly, we showed that the tumor suppressor activity resides in the propeptide domain of LOX (LOX-PP), an N-terminal domain produced by proteolytic cleavage during the physiological processing of LOX. Expression of LOX-PP reduced cell proliferation, cell migration, anchorage-independent growth in soft agar and formation of tumors in immunodeficient mice. By contrast, the C-terminal domain of LOX, which contains the enzymatic activity, had the opposite effects, corroborating that the tumor suppressor activity of LOX is mediated exclusively by its propeptide domain. Finally, we showed that LOX-PP inhibits ERK/MAPK signalling pathway, and that many pathways involved in cell cycle progression were significantly deregulated by LOX-PP, providing a mechanistic explanation to the cell proliferation inhibition observed upon LOX-PP expression. In summary, our observations indicate that deregulation of the LOX gene participates in Ewing sarcoma development and identify LOX-PP as a new therapeutic target for one of the most aggressive paediatric malignancies. These findings suggest that therapeutic strategies based on the administration of LOX propeptide or functional analogues could be useful for the treatment of this devastating paediatric cancer. PMID:23750284

García-García, Laura; de la Parra, Juan; Alonso, Javier

2013-01-01

178

Up-Regulation of FOXM1 by E6 Oncoprotein through the MZF1/NKX2-1 Axis Is Required for Human Papillomavirus–Associated Tumorigenesis12  

PubMed Central

PURPOSE: Foxhead box M1 (FOXM1) expression has been shown to be linked with human papillomavirus (HPV) 16/18–infected cervical cancer. However, the mechanism underlying the induction of FOXM1 in HPV 16/18–infected cancers remains elusive. EXPERIMENTAL DESIGN: The mechanistic actions of FOXM1 induced by the E6/NKX2-1 axis in tumor aggressiveness were elucidated in cellular and animal models. The prognostic value of FOXM1 for overall survival (OS) and relapse-free survival (RFS) in HPV-positive oral and lung cancers was assessed using Kaplan-Meier and Cox regression models. RESULTS: Herein, FOXM1 expression is upregulated by E6-mediated NKX2-1 in HPV-positive cervical, oral, and lung cancer cells. Induction of FOXM1 by E6 through the MZF1/NKX2-1 axis is responsible for HPV-mediated soft agar growth, invasiveness, and stemness through activating Wnt/?-catenin signaling pathway. In a nude mice model, metastatic lung tumor nodules in HPV 18 E6-positive GNM or HPV 16 E6-positive TL-1–injected nude mice were markedly decreased in both cell types with E6 knockdown, FOXM1 knockdown, or treatment with FOXM1 inhibitor (thiostrepton). Among the four subgroup patients, the worst FOXM1 prognostic value for OS and RFS was observed in HPV 16/18–positive patients with tumors with high-expressing FOXM1. CONCLUSIONS: Induction of FOXM1 by E6 oncoprotein through the MZF1/NKX2-1 axis may be responsible for HPV 16/18–mediated tumor progression and poor outcomes in HPV-positive patients. PMID:25425970

Chen, Po-Ming; Cheng, Ya-Wen; Wang, Yao-Chen; Wu, Tzu-Chin; Chen, Chih-Yi; Lee, Huei

2014-01-01

179

Human papillomavirus 16 E7 inactivator of retinoblastoma family proteins complements  

E-print Network

Human papillomavirus 16 E7 inactivator of retinoblastoma family proteins complements human tested whether the human papillomavirus type 16 E7 protein, which inactivates pRb family proteins papillomavirus (HPV), of which certain subtypes cause cervical cancer (2). The HPV16 E7 protein binds

180

Inactivation of the human papillomavirus E6 or E7 gene in cervical carcinoma cells by using a bacterial CRISPR/Cas RNA-guided endonuclease.  

PubMed

High-risk human papillomaviruses (HPVs), including HPV-16 and HPV-18, are the causative agents of cervical carcinomas and are linked to several other tumors of the anogenital and oropharyngeal regions. The majority of HPV-induced tumors contain integrated copies of the normally episomal HPV genome that invariably retain intact forms of the two HPV oncogenes E6 and E7. E6 induces degradation of the cellular tumor suppressor p53, while E7 destabilizes the retinoblastoma (Rb) protein. Previous work has shown that loss of E6 function in cervical cancer cells induces p53 expression as well as downstream effectors that induce apoptosis and cell cycle arrest. Similarly, loss of E7 allows increased Rb expression, leading to cell cycle arrest and senescence. Here, we demonstrate that expression of a bacterial Cas9 RNA-guided endonuclease, together with single guide RNAs (sgRNAs) specific for E6 or E7, is able to induce cleavage of the HPV genome, resulting in the introduction of inactivating deletion and insertion mutations into the E6 or E7 gene. This results in the induction of p53 or Rb, leading to cell cycle arrest and eventual cell death. Both HPV-16- and HPV-18-transformed cells were found to be responsive to targeted HPV genome-specific DNA cleavage. These data provide a proof of principle for the idea that vector-delivered Cas9/sgRNA combinations could represent effective treatment modalities for HPV-induced cancers. Importance: Human papillomaviruses (HPVs) are the causative agents of almost all cervical carcinomas and many other tumors, including many head and neck cancers. In these cancer cells, the HPV DNA genome is integrated into the cellular genome, where it expresses high levels of two viral oncogenes, called E6 and E7, that are required for cancer cell growth and viability. Here, we demonstrate that the recently described bacterial CRISPR/Cas RNA-guided endonuclease can be reprogrammed to target and destroy the E6 or E7 gene in cervical carcinoma cells transformed by HPV, resulting in cell cycle arrest, leading to cancer cell death. We propose that viral vectors designed to deliver E6- and/or E7-specific CRISPR/Cas to tumor cells could represent a novel and highly effective tool to treat and eliminate HPV-induced cancers. PMID:25100830

Kennedy, Edward M; Kornepati, Anand V R; Goldstein, Michael; Bogerd, Hal P; Poling, Brigid C; Whisnant, Adam W; Kastan, Michael B; Cullen, Bryan R

2014-10-01

181

Alteration of a single amino acid in the basic domain of Marek's disease virus Meq oncoprotein plays an important role in T-cell transformation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Marek’s disease virus encoded oncoprotein, Meq, has been shown to play a major role in transformation of T-lymphocytes. We have earlier shown that replacement of the meq gene in the very virulent strain Md5 with that of vaccine strain CVI988/Rispens resulted in virus attenuation in chickens. To dete...

182

Complex formation of human papillomavirus E7 proteins with the retinoblastoma tumor suppressor gene product.  

PubMed

The E7 proteins encoded by the human papillomaviruses (HPVs) associated with anogenital lesions share significant amino acid sequence homology. The E7 proteins of these different HPVs were assessed for their ability to form complexes with the retinoblastoma tumor suppressor gene product (p105-RB). Similar to the E7 protein of HPV-16, the E7 proteins of HPV-18, HBV-6b and HPV-11 were found to associate with p105-RB in vitro. The E7 proteins of HPV types associated with a high risk of malignant progression (HPV-16 and HPV-18) formed complexes with p105-RB with equal affinities. The E7 proteins encoded by HPV types 6b and 11, which are associated with clinical lesions with a lower risk for progression, bound to p105-RB with lower affinities. The E7 protein of the bovine papillomavirus type 1 (BPV-1), which does not share structural similarity in the amino terminal region with the HPV E7 proteins, was unable to form a detectable complex with p105-RB. The amino acid sequences of the HPV-16 E7 protein involved in complex formation with p105-RB in vitro have been mapped. Only a portion of the sequences that are conserved between the HPV E7 proteins and AdE1A were necessary for association with p105-RB. Furthermore, the HPV-16 E7-p105-RB complex was detected in an HPV-16-transformed human keratinocyte cell line. PMID:2556261

Münger, K; Werness, B A; Dyson, N; Phelps, W C; Harlow, E; Howley, P M

1989-12-20

183

Identification of pivotal cellular factors involved in HPV-induced dysplastic and neoplastic cervical pathologies.  

PubMed

Cervical carcinoma represents the paradigm of virus-induced cancers, where virtually all cervical cancers come from previous "high-risk" HPV infection. The persistent expression of the HPV viral oncoproteins E6 and E7 is responsible for the reprogramming of fundamental cellular functions in the host cell, thus generating a noticeable, yet only partially explored, imbalance in protein molecular networks and cell signaling pathways. Eighty-eight cellular factors, identified as HPV direct or surrogate targets, were chosen and monitored in a retrospective analysis for their mRNA expression in HPV-induced cervical lesions, from dysplasia to cancer. Real-time quantitative PCR (qPCR) was performed by using formalin-fixed, paraffin embedded archival samples. Gene expression analysis identified 40 genes significantly modulated in LSIL, HSIL, and squamous cervical carcinoma. Interestingly, among these, the expression level of a panel of four genes, TOP2A, CTNNB1, PFKM, and GSN, was able to distinguish between normal tissues and cervical carcinomas. Immunohistochemistry was also done to assess protein expression of two genes among those up-regulated during the transition between dysplasia and carcinoma, namely E2F1 and CDC25A, and their correlation with clinical parameters. Besides the possibility of significantly enhancing the use of some of these factors in diagnostic or prognostic procedures, these data clearly outline specific pathways, and thus key biological processes, altered in cervical dysplasia and carcinoma. Deeper insight on how these molecular mechanisms work may help widen the spectrum of novel innovative approaches to these virus-induced cell pathologies. PMID:24105779

Mattarocci, Stefano; Abbruzzese, Claudia; Mileo, Anna M; Carosi, Mariantonia; Pescarmona, Edoardo; Vico, Carmen; Federico, Antonio; Vizza, Enrico; Corrado, Giacomo; Arisi, Ivan; Felsani, Armando; Paggi, Marco G

2014-04-01

184

Identification and Characterization of Mechanism of Action of P61-E7, a Novel Phosphine Catalysis-Based Inhibitor of Geranylgeranyltransferase-I  

PubMed Central

Small molecule inhibitors of protein geranylgeranyltransferase-I (GGTase-I) provide a promising type of anticancer drugs. Here, we first report the identification of a novel tetrahydropyridine scaffold compound, P61-E7, and define effects of this compound on pancreatic cancer cells. P61-E7 was identified from a library of allenoate-derived compounds made through phosphine-catalyzed annulation reactions. P61-E7 inhibits protein geranylgeranylation and blocks membrane association of geranylgeranylated proteins. P61-E7 is effective at inhibiting both cell proliferation and cell cycle progression, and it induces high p21CIP1/WAF1 level in human cancer cells. P61-E7 also increases p27Kip1 protein level and inhibits phosphorylation of p27Kip1 on Thr187. We also report that P61-E7 treatment of Panc-1 cells causes cell rounding, disrupts actin cytoskeleton organization, abolishes focal adhesion assembly and inhibits anchorage independent growth. Because the cellular effects observed pointed to the involvement of RhoA, a geranylgeranylated small GTPase protein shown to influence a number of cellular processes including actin stress fiber organization, cell adhesion and cell proliferation, we have evaluated the significance of the inhibition of RhoA geranylgeranylation on the cellular effects of inhibitors of GGTase-I (GGTIs). Stable expression of farnesylated RhoA mutant (RhoA-F) results in partial resistance to the anti-proliferative effect of P61-E7 and prevents induction of p21CIP1/WAF1 and p27Kip1 by P61-E7 in Panc-1 cells. Moreover, stable expression of RhoA-F rescues Panc-1 cells from cell rounding and inhibition of focal adhesion formation caused by P61-E7. Taken together, these findings suggest that P61-E7 is a promising GGTI compound and that RhoA is an important target of P61-E7 in Panc-1 pancreatic cancer cells. PMID:22028818

Chan, Lai N.; Fiji, Hannah D. G.; Watanabe, Masaru; Kwon, Ohyun; Tamanoi, Fuyuhiko

2011-01-01

185

Low- and high-risk human papillomavirus E7 proteins regulate p130 differently  

SciTech Connect

The E7 protein of high-risk human papillomaviruses (HR HPVs) targets pRb family members (pRb, p107 and p130) for degradation; low-risk (LR) HPV E7 only targets p130 for degradation. The effect of HR HPV 16 E7 and LR HPV 6 E7 on p130 intracellular localization and half-life was examined. Nuclear/cytoplasmic fractionation and immunofluorescence showed that, in contrast to control and HPV 6 E7-expressing cells, a greater amount of p130 was present in the cytoplasm in the presence of HPV 16 E7. The half-life of p130, relative to control cells, was decreased in the cytoplasm in the presence of HPV 6 E7 or HPV 16 E7, but only decreased by HPV 6 E7 in the nucleus. Inhibition of proteasomal degradation extended the half-life of p130, regardless of intracellular localization. These results suggest that there may be divergent mechanisms by which LR and HR HPV E7 target p130 for degradation.

Barrow-Laing, Lisa; Chen Wei [Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Roman, Ann, E-mail: aroman@iupui.ed [Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)

2010-05-10

186

Polyomavirus Middle T Antigen Induces the Transcription of Osteopontin, a Gene Important for the Migration of Transformed Cells  

Microsoft Academic Search

Middle T antigen (MT) is the principal oncoprotein of murine polyomavirus. Experiments on the acute immediate effects of MT expression on cellular RNA levels showed that expression of osteopontin (OPN) was strongly induced by MT expression. Osteopontin is a protein known to be associated with cancer. It has a role in tumor progression and invasion. Protein analysis confirmed that MT

Kerry A. Whalen; Georg F. Weber; Thomas L. Benjamin; Brian S. Schaffhausen

2008-01-01

187

Isolation and characterization of a fourth Arabidopsis thaliana G-box-binding factor, which has similarities to Fos oncoprotein.  

PubMed Central

A fourth member of the Arabidopsis G-box-binding factor (GBF) family of bZIP proteins, GBF4, has been isolated and characterized. In a manner reminiscent of the Fos-related oncoproteins of mammalian systems, GBF4 cannot bind to DNA as a homodimer, although it contains a basic region capable of specifically recognizing the G-box and G-box-like elements. However, GBF4 can interact with GBF2 and GBF3 to bind DNA as heterodimers. Mutagenesis of the leucine zipper of GBF4 indicates that the mutation of a single amino acid confers upon the protein the ability to recognize the G-box as a homodimer, apparently by altering the charge distribution within the leucine zipper. Images PMID:8146148

Menkens, A E; Cashmore, A R

1994-01-01

188

A novel dithiocarbamate derivative induces cell apoptosis through p53-dependent intrinsic pathway and suppresses the expression of the E6 oncogene of human papillomavirus 18 in HeLa cells.  

PubMed

Dithiocarbamates (DTCs) exhibit a broad spectrum of antitumor activities, however, their molecular mechanisms of antitumor have not yet been elucidated. Previously, we have synthesized a series of novel dithiocarbamate derivatives. These DTCs were examined for cytotoxic activities against five human cancer cell lines. In this study, one of dithiocarbamate (DTC1) with higher potential for HeLa cells was chosen to investigate molecular mechanisms for its anti-tumor activities. DTC1 could inhibit proliferation, and highly induce apoptosis in HeLa cells by activating caspase-3, -6 and -9; moreover, activities of caspase-3, -6 and -9 were inhibited by pan-caspase inhibitor, Z-VAD-FMK. Furthermore, DTC1 decreased the levels of Bcl-2 and Bcl-xL, and increased expression of cytosol cytochrome c, Bak, Bax and p53 in a time-dependent manner but had no effect on the level of Rb. It was shown that DTC1 induced HeLa cells apoptosis through a p53-dependent pathway as tested by the wild type p53 inhibitor, pifithrin-?. Additionally, the relative expression of E6 and E7 were evaluated in HPV18-positive (HeLa cells) by real-time PCR and western blotting. The results firstly demonstrated that DTC1 suppressed both expression of E6 mRNA and E6 oncoprotein, but had no effect on the expression of E7 mRNA and protein in HPV18. Our results suggested that DTC1 may serve as novel chemotherapeutic agents in the treatment of cervical cancer and potential anti-HPV virus candidates that merit further studies. PMID:25772545

Li, Yanhong; Qi, Hongxue; Li, Xiaobo; Hou, Xueling; Lu, Xueying; Xiao, Xiangwen

2015-06-01

189

The Aqueous Extract of Ficus religiosa Induces Cell Cycle Arrest in Human Cervical Cancer Cell Lines SiHa (HPV-16 Positive) and Apoptosis in HeLa (HPV-18 Positive)  

PubMed Central

Natural products are being extensively explored for their potential to prevent as well as treat cancer due to their ability to target multiple molecular pathways. Ficus religiosa has been shown to exert diverse biological activities including apoptosis in breast cancer cell lines. In the present study, we report the anti-neoplastic potential of aqueous extract of F. religiosa (FRaq) bark in human cervical cancer cell lines, SiHa and HeLa. FRaq altered the growth kinetics of SiHa (HPV-16 positive) and HeLa (HPV-18 positive) cells in a dose-dependent manner. It blocked the cell cycle progression at G1/S phase in SiHa that was characterized by an increase in the expression of p53, p21 and pRb proteins with a simultaneous decrease in the expression of phospho Rb (ppRb) protein. On the other hand, in HeLa, FRaq induced apoptosis through an increase in intracellular Ca2+ leading to loss of mitochondrial membrane potential, release of cytochrome-c and increase in the expression of caspase-3. Moreover, FRaq reduced the migration as well as invasion capability of both the cervical cancer cell lines accompanied with downregulation of MMP-2 and Her-2 expression. Interestingly, FRaq reduced the expression of viral oncoproteins E6 and E7 in both the cervical cancer cell lines. All these data suggest that F. religiosa could be explored for its chemopreventive potential in cervical cancer. PMID:23922932

Choudhari, Amit S.; Suryavanshi, Snehal A.; Kaul-Ghanekar, Ruchika

2013-01-01

190

The aqueous extract of Ficus religiosa induces cell cycle arrest in human cervical cancer cell lines SiHa (HPV-16 Positive) and apoptosis in HeLa (HPV-18 positive).  

PubMed

Natural products are being extensively explored for their potential to prevent as well as treat cancer due to their ability to target multiple molecular pathways. Ficus religiosa has been shown to exert diverse biological activities including apoptosis in breast cancer cell lines. In the present study, we report the anti-neoplastic potential of aqueous extract of F. religiosa (FRaq) bark in human cervical cancer cell lines, SiHa and HeLa. FRaq altered the growth kinetics of SiHa (HPV-16 positive) and HeLa (HPV-18 positive) cells in a dose-dependent manner. It blocked the cell cycle progression at G1/S phase in SiHa that was characterized by an increase in the expression of p53, p21 and pRb proteins with a simultaneous decrease in the expression of phospho Rb (ppRb) protein. On the other hand, in HeLa, FRaq induced apoptosis through an increase in intracellular Ca(2+) leading to loss of mitochondrial membrane potential, release of cytochrome-c and increase in the expression of caspase-3. Moreover, FRaq reduced the migration as well as invasion capability of both the cervical cancer cell lines accompanied with downregulation of MMP-2 and Her-2 expression. Interestingly, FRaq reduced the expression of viral oncoproteins E6 and E7 in both the cervical cancer cell lines. All these data suggest that F. religiosa could be explored for its chemopreventive potential in cervical cancer. PMID:23922932

Choudhari, Amit S; Suryavanshi, Snehal A; Kaul-Ghanekar, Ruchika

2013-01-01

191

Differential Processing of let-7a Precursors Influences RRM2 Expression and Chemosensitivity in Pancreatic Cancer: Role of LIN-28 and SET Oncoprotein  

PubMed Central

Overexpression of ribonucleotide reductase subunit M2 (RRM2), involved in deoxyribonucleotide synthesis, drives the chemoresistance of pancreatic cancer to nucleoside analogs (e.g., gemcitabine). While silencing RRM2 by synthetic means has shown promise in reducing chemoresistance, targeting endogenous molecules, especially microRNAs (miRNAs), to advance chemotherapeutic outcomes has been poorly explored. Based on computational predictions, we hypothesized that the let-7 tumor suppressor miRNAs will inhibit RRM2-mediated gemcitabine chemoresistance in pancreatic cancer. Reduced expression of the majority of let-7 miRNAs with an inverse relationship to RRM2 expression was identified in innately gemcitabine-resistant pancreatic cancer cell lines. Direct binding of let-7 miRNAs to the 3? UTR of RRM2 transcripts identified post-transcriptional regulation of RRM2 influencing gemcitabine chemosensitivity. Intriguingly, overexpression of human precursor-let-7 miRNAs led to differential RRM2 expression and chemosensitivity responses in a poorly differentiated pancreatic cancer cell line, MIA PaCa-2. Defective processing of let-7a precursors to mature forms, in part, explained the discrepancies observed with let-7a expressional outcomes. Consistently, the ratios of mature to precursor let-7a were progressively reduced in gemcitabine-sensitive L3.6pl and Capan-1 cell lines induced to acquire gemcitabine resistance. Besides known regulators of let-7 biogenesis (e.g., LIN-28), short hairpin RNA library screening identified several novel RNA binding proteins, including the SET oncoprotein, to differentially impact let-7 biogenesis and chemosensitivity in gemcitabine-sensitive versus -resistant pancreatic cancer cells. Further, LIN-28 and SET knockdown in the cells led to profound reductions in cellular proliferation and colony-formation capacities. Finally, defective processing of let-7a precursors with a positive correlation to RRM2 overexpression was identified in patient-derived pancreatic ductal adenocarcinoma (PDAC) tissues. These data demonstrate an intricate post-transcriptional regulation of RRM2 and chemosensitivity by let-7a and that the manipulation of regulatory proteins involved in let-7a transcription/processing may provide a mechanism for improving chemotherapeutic and/or tumor growth control responses in pancreatic cancer. PMID:23335963

Bhutia, Yangzom Doma; Hung, Sau Wai; Krentz, Madeline; Patel, Dimal; Lovin, Dylan; Manoharan, Radhika; Thomson, J. Michael; Govindarajan, Rajgopal

2013-01-01

192

McKay's E7 observation on the Baby Monster Gerald Hohn  

E-print Network

McKay's E7 observation on the Baby Monster Gerald H¨ohn Department of Mathematics, Kansas State; Secondary 20B25. Abstract In this paper, we study McKay's E7 observation on the Baby Monster. We show that there is a natural correspondence between dihedral groups of the Baby Monster and certain vertex operator subalgebras

Hoehn, Gerald

193

McKay's E7 observation on the Baby Monster Gerald Hohn  

E-print Network

McKay's E7 observation on the Baby Monster Gerald H¨ohn Department of Mathematics, Kansas State; Secondary 20B25. Abstract In this paper, we study McKay's E7 observation on the Baby Monster between dihedral subgroups of the Baby Monster and certain subalgebras of the Baby Monster vertex operator

Hoehn, Gerald

194

ORIGINAL PAPER Identification of a proliferation gene cluster associated with HPV E6/E7  

E-print Network

ORIGINAL PAPER Identification of a proliferation gene cluster associated with HPV E6/E7 expression; 7 De´partement de Transfert, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France Specific HPV suggest that HPV E6/E7 expression level plays a key role in the progression of invasive carcinoma

Domany, Eytan

195

Studies on transcriptional regulation of the mucosal T-cell integrin ?E?7 (CD103)  

PubMed Central

Integrin ?E?7 is expressed almost exclusively by mucosal T cells and mucosal dendritic antigen-presenting cells (APCs) and is thought to be induced locally by transforming growth factor-? (TGF-?). In mice, mRNA for the ?E subunit was found to be abundant in mucosal T cells but absent from other tissues. Exposure of a T-cell line to TGF-? strongly up-regulated ?E mRNA levels within 30 min, and nuclear run-on experiments established that regulation occurred at the level of transcription. The organization of the human ?E gene and a very closely linked novel gene, ELG, was determined. The ?E promoter was tested in T cells and fibroblasts and functioned equally well in both cell types and did not confer TGF-? responsiveness. Regions of the promoter providing enhancer activity and phorbol 12-myristate 13-acetate (PMA) responsiveness were identified by deletion studies. DNAse 1 hypersensitivity analysis of 36 kb of the ?E gene revealed one hypersensitive site, found only in ?E+ cells, located near the transcription start points. These results show that, unlike the situation with other integrins, lineage specificity and cytokine responsiveness of ?E transcription are not conferred by the proximal promoter. Specificity may depend on distant control elements that have not yet been identified. PMID:11412301

Robinson, Paul W; Green, Sally J; Carter, Christine; Coadwell, John; Kilshaw, Peter J

2001-01-01

196

Exosomal sorting of the viral oncoprotein LMP1 is restrained by TRAF2 association at signalling endosomes  

PubMed Central

The Epstein–Barr virus (EBV)-encoded oncoprotein latent membrane protein 1 (LMP1) constitutively activates nuclear factor ?B (NF?B) from intracellular membranes to promote cell growth and survival. LMP1 associates with CD63 in intracellular membranes and is released via exosomes. Whether tumour necrosis factor (TNF) receptor-associated factors (TRAFs) mediate LMP1 NF?B signalling from endosomes and modulate exosomal sorting is unknown. In this article, we show that LMP1–TRAF2 signalling complexes accumulate at endosomes in a palmitoylation-dependent manner, thereby driving LMP1-dependent oncogenicity. Palmitoylation is a reversible post-translational modification and is considered to function as a membrane anchor for proteins. Mutagenesis studies showed that LMP1–TRAF2 trafficking to endosomes is dependent on one single cysteine residue (C78), a known palmitoylation site of LMP1. Notably, growth assays in soft agar revealed that oncogenic properties of the palmitoylation-deficient LMP1 mutant C78A were diminished compared to wild-type LMP1. Since LMP1 recruitment of TRAF2 and downstream NF?B signalling were not affected by a disturbance in palmitoylation, the specific localization of LMP1 at endosomal membranes appears crucial for its transforming potential. The importance of palmitoylation for trafficking to and signalling from endosomal membranes was not restricted to LMP1, as similar observations were made for the cellular oncoproteins Src and Fyn. Despite abundant LMP1–TRAF2 association at endosomal membranes TRAF2 could not be detected in exosomes by Western blotting or proteomics. Interestingly, point mutations that prevented TRAF binding strongly promoted the sorting and release of LMP1 via exosomes. These observations reveal that LMP1–TRAF2 complexes at endosomes support oncogenic NF?B activation and suggest that LMP1 dissociates from the activated signalling complexes upon sorting into intraluminal vesicles. We propose that “signalling endosomes” in EBV-infected tumour cells can fuse with the plasma membrane, explaining LMP1 release via exosomes. PMID:25865256

Verweij, Frederik J.; de Heus, Cecilia; Kroeze, Stefanie; Cai, Houjian; Kieff, Elliott; Piersma, Sander R.; Jimenez, Connie R.; Middeldorp, Jaap M.; Pegtel, Dirk Michiel

2015-01-01

197

Controversial aspects of oncogene-induced senescence  

PubMed Central

Oncogene-induced senescence (OIS) is a fail-safe mechanism that is developed to suppress cell proliferation caused by aberrant activation of oncoproteins in normal cells. Most of the available literature considers senescence to be caused by activated RAS or RAF proteins. In the current review, we will discuss some of the controversial aspects of RAS- or RAF-induced senescence in different types of normal cells: are tumor suppressors important for OIS? What is the role of DNA damage in OIS? Are there different types of OIS? PMID:23095636

Bianchi-Smiraglia, Anna; Nikiforov, Mikhail A.

2012-01-01

198

Metastasis-associated protein 1 (MTA1) is an essential downstream effector of the c-MYC oncoprotein.  

PubMed

The c-myc oncogene is among the most commonly overexpressed genes in human cancer. c-myc encodes a basic helix-loop-helix/leucine zipper (bHLH/LZ) transcription factor (c-MYC) that activates a cascade of downstream targets that ultimately mediate cellular transformation. Although a large number of genes are regulated by c-MYC, only a few have been functionally linked to c-MYC-mediated transformation. By expression profiling, the metastasis-associated protein 1 (MTA1) gene was identified here as a target of the c-MYC oncoprotein in primary human cells, a result confirmed in human cancer cells. MTA1 itself has been previously implicated in cellular transformation, in part through its ability to regulate the epithelial-to-mesenchymal transition and metastasis. MTA1 is a component of the Mi-2/nucleosome remodeling and deacetylating (NURD) complex that contains both histone deacetylase and nucleosome remodeling activity. The data reported here demonstrate that endogenous c-MYC binds to the genomic MTA1 locus and recruits transcriptional coactivators. Most importantly, short hairpin RNA (shRNA)-mediated knockdown of MTA1 blocks the ability of c-MYC to transform mammalian cells. These data implicate MTA1 and the Mi-2/NURD complex as one of the first downstream targets of c-MYC function that are essential for the transformation potential of c-MYC. PMID:16172399

Zhang, Xiao-Yong; DeSalle, Lauren M; Patel, Jagruti H; Capobianco, Anthony J; Yu, Duonan; Thomas-Tikhonenko, Andrei; McMahon, Steven B

2005-09-27

199

Dysregulating IRES-dependent translation contributes to over-expression of the Aurora A kinase onco-protein  

PubMed Central

Over-expression of the oncoprotein, Aurora A kinase occurs in multiple types of carcinomas, often early during cell transformation. To identify mechanism(s) contributing to enhanced Aurora A protein expression, we examined normal human lung fibroblast and breast epithelial cells and compared them to non-tumorigenic breast (MCF10A and MCF12A) and tumorigenic breast and cervical epithelial cell lines (MCF-7 and HeLa S3, respectively). A subset of these immortalized lines (MCF10, MCF12A, and HeLa S3) exhibited increased levels of Aurora A protein, independent of tumorigenicity. The increase in Aurora A protein expression in these immortalized cells was not due to increased transcription/RNA stability, protein half-life or cap-dependent translation. Assays utilizing monocistronic and dicistronic RNA constructs revealed that the Aurora A 5? leader contains an internal ribosomal entry site (IRES), which is regulated through the cell cycle, peaking in G2/M phase. Moreover, IRES activity was increased in the immortalized cell lines in which Aurora A protein expression was also enhanced. Additional assays indicated that the increased internal initiation is specific to the Aurora A IRES and may be an early event during cancer progression. Taken together, these results identify a novel mechanism contributing to Aurora A kinase over-expression and possibly to immortalization leading to carcinogenesis. PMID:23661421

Dobson, Tara; Chen, Juan; Krushel, Les A.

2014-01-01

200

Interplay Between Oncoproteins and Antioxidant Enzymes in Esophageal Carcinoma Treated Without and With Chemoradiotherapy: A Prospective Study  

SciTech Connect

Purpose: To analyze p53, bcl-2, c-myc, and cyclooxygenase-2 protein expression changes and examine their relationship with various antioxidant enzymes in esophageal carcinoma patients. Methods and Materials: Patients in Group 1 underwent transhiatal esophagectomy and those in Group 2 were administered chemoradiotherapy followed by surgery after 4 weeks of neoadjuvant therapy. Results: The relationship analysis among the various protein markers and antioxidant enzymes showed an inverse correlation between bcl-2 and superoxide dismutase/catalase in tumor tissues, irrespective of the treatment arm followed. An important positive association was observed between bcl-2 and reduced glutathione levels in the tumor tissue of patients receiving neoadjuvant therapy. Another apoptosis-modulating marker, c-myc, in the tumor tissue of Group 2 patients showed similar pattern levels (high and low) as that of superoxide dismutase/catalase. The association of cyclooxygenase-2 and p53 with various antioxidant enzymes showed a significant positive correlation between cyclooxygenase-2 expression and catalase activity and an inverse trend between p53 expression and superoxide dismutase and catalase activity in the tumor tissue of patients given neoadjuvant therapy. In addition, patients with overexpressed p53 protein levels had lower glutathione peroxidase enzyme levels and vice versa in the tumor tissue of patients who had undergone surgery as their main mode of treatment. Conclusion: The results of this study broaden the insight into the relationships shared among oncoproteins and the antioxidant defense system, and this could be helpful in the clinical management of esophageal carcinoma.

Kaur, Tranum [Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Gupta, Rajesh [Department of General Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Vaiphei, Kim [Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Kapoor, Rakesh [Department of Radiotherapy, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Gupta, N.M. [Department of General Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Khanduja, K.L. [Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India)], E-mail: klkhanduja@gmail.com

2008-02-01

201

The oncoprotein HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote the proliferation of breast cancer cells  

SciTech Connect

Highlights: •HBXIP is able to upregulate the expression of PDGFB in breast cancer cells. •HBXIP serves as a coactivator of activating transcription factor Sp1. •HBXIP stimulates the PDGFB promoter via activating transcription factor Sp1. •HBXIP promotes the proliferation of breast cancer cell via upregulating PDGFB. -- Abstract: We have reported that the oncoprotein hepatitis B virus X-interacting protein (HBXIP) acts as a novel transcriptional coactivator to promote proliferation and migration of breast cancer cells. Previously, we showed that HBXIP was able to activate nuclear factor-?B (NF-?B) in breast cancer cells. As an oncogene, the platelet-derived growth factor beta polypeptide (PDGFB) plays crucial roles in carcinogenesis. In the present study, we found that both HBXIP and PDGFB were highly expressed in breast cancer cell lines. Interestingly, HBXIP was able to increase transcriptional activity of NF-?B through PDGFB, suggesting that HBXIP is associated with PDGFB in the cells. Moreover, HBXIP was able to upregulate PDGFB at the levels of mRNA, protein and promoter in the cells. Then, we identified that HBXIP stimulated the promoter of PDGFB through activating transcription factor Sp1. In function, HBXIP enhanced the proliferation of breast cancer cells through PDGFB in vitro. Thus, we conclude that HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote proliferation of breast cancer cells.

Zhang, Yingyi; Zhao, Yu; Li, Leilei; Shen, Yu; Cai, Xiaoli [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China); Zhang, Xiaodong, E-mail: zhangxd@nankai.edu.cn [Department of Cancer Research, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Cancer Research, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ye, Lihong, E-mail: yelihong@nankai.edu.cn [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)

2013-05-03

202

Oncogenic nexus of cancerous inhibitor of protein phosphatase 2A (CIP2A): An oncoprotein with many hands  

PubMed Central

Oncoprotein CIP2A a Cancerous Inhibitor of PP2A forms an “oncogenic nexus” by virtue of its control on PP2A and MYC stabilization in cancer cells. The expression and prognostic function of CIP2A in different solid tumors including colorectal carcinoma, head & neck cancers, gastric cancers, lung carcinoma, cholangiocarcinoma, esophageal cancers, pancreatic carcinoma, brain cancers, breast carcinoma, bladder cancers, ovarian carcinoma, renal cell carcinomas, tongue cancers, cervical carcinoma, prostate cancers, and oral carcinoma as well as a number of hematological malignancies are just beginning to emerge. Herein, we reviewed the recent progress in our understanding of (1) how an “oncogenic nexus” of CIP2A participates in the tumorigenic transformation of cells and (2) how we can prospect/view the clinical relevance of CIP2A in the context of cancer therapy. The review will try to understand the role of CIP2A (a) as a biomarker in cancers and evaluate the prognostic value of CIP2A in different cancers (b) as a therapeutic target in cancers and (c) in drug response and developing chemo-resistance in cancers. PMID:25015035

De, Pradip; Carlson, Jennifer; Leyland-Jones, Brian; Dey, Nandini

2014-01-01

203

Further Stimulation of Cellular Immune Responses through Association of HPV-16 E6, E7 and L1 Genes in order to produce more Effective Therapeutic DNA Vaccines in Cervical Cancer Model  

PubMed Central

Background Cervical cancer has been shown to be highly associated with human papillomavirus (HPV) infection. The viral oncogenes E6 and E7 are constantly expressed by the tumor cells and are therefore potent targets for therapeutic genetic vaccination. In the present study, it was investigated the potential effect of HPV-16 E6, E7 and L1 co-administration to activate specific cytotoxic T lymphocytes in tumor mice models. Methods The HPV-16 E6, E7 and L1 genes from Iranian isolate were separately inserted into the mammalian expression vector, pcDNA3, to construct the DNA vaccine candidates. Tumor-bearing Animals (C57BL/6 mice) were immunized with the vaccine candidate; then, Lymphocyte Proliferation Assay (LPA) and relative tumor volume measurements were carried out in order to examine the immunological effects of the vaccine. Results Obtained results showed that co-administration of the HPV-16 E6, E7 and L1 DNA induced HPV-16 specific cellular immune responses and also protected against TC-1-induced tumor in vivo compared with negative controls. Conclusion The results showed that mixed delivery systems might be valuable to improve the magnitude of the induced immune responses and confirmed therapeutic effects of HPV-16 E6, E7 through cytotoxic T lymphocyte induction and illustrate the new promising role for HPV-16 L1 CTL epitopes as a suitable CTL inducer.

Fazeli, Maryam; Soleimanjahi, Hoorieh; Dadashzadeh, Simin

2015-01-01

204

Human Papilloma Virus (HPV) and Host Cellular Interactions  

Microsoft Academic Search

Viral-induced carcinogenesis has been attributed to the ability of viral oncoproteins to target and interact with the host\\u000a cellular proteins. It is generally accepted that Human papilloma virus (HPV) E6 and E7 function as the dominant oncoproteins\\u000a of ‘high-risk’ HPVs by altering the function of critical cellular proteins. Initially it was shown that HPV E6 enhances the\\u000a degradation of p53,

Ioannis N. Mammas; George Sourvinos; Athena Giannoudis; Demetrios A. Spandidos

2008-01-01

205

Telomerase Activation by Human Papillomavirus Type 16 E6 Protein: Induction of Human Telomerase Reverse Transcriptase Expression through Myc and GC-Rich Sp1 Binding Sites  

Microsoft Academic Search

High-risk human papillomaviruses (HPVs) immortalize keratinocytes by disrupting the retinoblastoma protein (Rb)\\/p16 pathway and activating telomerase. The E7 oncoprotein targets Rb, while the E6 oncoprotein induces telomerase activity in human keratinocytes. This study has examined the mechanism by which E6 activates telomerase. Expression of human telomerase reverse transcriptase (hTERT), the catalytic subunit of telomerase, was found to be increased in

STEPHEN T. OH; SATURO KYO; LAIMONIS A. LAIMINS

2001-01-01

206

C/EBP?, C/EBP? Oncoproteins, or C/EBP? Preferentially Bind NF-?B p50 Compared with p65 Focusing Therapeutic Targeting on the C/EBP:p50 Interaction  

PubMed Central

Canonical NF-?B activation signals stimulate nuclear translocation of p50:p65, replacing inhibitory p50:p50 with activating complexes on chromatin. C/EBP interaction with p50 homodimers provides an alternative pathway for NF-?B target gene activation, and interaction with p50:p65 may enhance gene activation. We previously found that C/EBP? cooperates with p50 but not p65 to induce Bcl-2 transcription and that C/EBP? induces Nfkb1/p50 but not RelA/p65 transcription. Using p50 and p65 variants containing the FLAG epitope at their N- or C-termini, we now demonstrate that C/EBP?, C/EBP? myeloid oncoproteins, or the LAP1, LAP2, or LIP isoforms of C/EBP? have markedly higher affinity for p50 in comparison to p65. Deletion of the p65 trans-activation domain did not increase p65 affinity for C/EBPs, suggesting that unique residues in p50 account for specificity, and clustered mutation of HSDL in the “p50 insert” lacking in p65 weakens interaction. Also, in contrast to Nfkb1 gene deletion, absence of the RelA gene does not reduce Bcl-2 or Cebpa RNA in unstimulated cells or prevent interaction of C/EBP? with the Bcl-2 promoter. Saturating mutagenesis of the C/EBP? basic region identifies R300 and nearby residues, identical in C/EBP?, as critical for interaction with p50. These findings support the conclusion that C/EBPs activate NF-?B target genes via contact with p50 even in the absence of canonical NF-?B activation and indicate that targeting C/EBP:p50 rather than C/EBP:p65 interaction in the nucleus will prove effective for inflammatory or malignant conditions, alone or synergistically with agents acting in the cytoplasm to reduce canonical NF-?B activation. PMID:21813505

Dooher, Julia E.; Paz-Priel, Ido; Houng, Simone; Baldwin, Albert S.; Friedman, Alan D.

2011-01-01

207

Identification of target genes of synovial sarcoma-associated fusion oncoprotein using human pluripotent stem cells  

SciTech Connect

Highlights: ? We tried to identify targets of synovial sarcoma (SS)-associated SYT–SSX fusion gene. ? We established pluripotent stem cell (PSC) lines with inducible SYT–SSX gene. ? SYT–SSX responsive genes were identified by the induction of SYT–SSX in PSC. ? SS-related genes were selected from database by in silico analyses. ? 51 genes were finally identified among SS-related genes as targets of SYT–SSX in PSC. -- Abstract: Synovial sarcoma (SS) is a malignant soft tissue tumor harboring chromosomal translocation t(X; 18)(p11.2; q11.2), which produces SS-specific fusion gene, SYT–SSX. Although precise function of SYT–SSX remains to be investigated, accumulating evidences suggest its role in gene regulation via epigenetic mechanisms, and the product of SYT–SSX target genes may serve as biomarkers of SS. Lack of knowledge about the cell-of-origin of SS, however, has placed obstacle in the way of target identification. Here we report a novel approach to identify SYT–SSX2 target genes using human pluripotent stem cells (hPSCs) containing a doxycycline-inducible SYT–SSX2 gene. SYT–SSX2 was efficiently induced both at mRNA and protein levels within three hours after doxycycline administration, while no morphological change of hPSCs was observed until 24 h. Serial microarray analyses identified genes of which the expression level changed more than twofold within 24 h. Surprisingly, the majority (297/312, 95.2%) were up-regulated genes and a result inconsistent with the current concept of SYT–SSX as a transcriptional repressor. Comparing these genes with SS-related genes which were selected by a series of in silico analyses, 49 and 2 genes were finally identified as candidates of up- and down-regulated target of SYT–SSX, respectively. Association of these genes with SYT–SSX in SS cells was confirmed by knockdown experiments. Expression profiles of SS-related genes in hPSCs and human mesenchymal stem cells (hMSCs) were strikingly different in response to the induction of SYT–SSX, and more than half of SYT–SSX target genes in hPSCs were not induced in hMSCs. These results suggest the importance of cellular context for correct understanding of SYT–SSX function, and demonstrated how our new system will help to overcome this issue.

Hayakawa, Kazuo [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ikeya, Makoto [Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan)] [Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Fukuta, Makoto [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Woltjen, Knut [Department of Reprogramming Sciences, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan)] [Department of Reprogramming Sciences, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Tamaki, Sakura; Takahara, Naoko; Kato, Tomohisa; Sato, Shingo [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan)] [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Otsuka, Takanobu [Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan)] [Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Toguchida, Junya, E-mail: togjun@frontier.kyoto-u.ac.jp [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto (Japan)

2013-03-22

208

Immortalization of human extravillous cytotrophoblasts by human papilloma virus gene E6E7: sequential cytogenetic and molecular genetic characterization  

Microsoft Academic Search

Extravillous cytotrophoblast (EVCT) cultures from the normal placentas of three pregnant women were transfected by HPVE6E7. Sequential cytogenetic and molecular analyses were performed to delineate genetic events that may be critical for cell immortalization. One line, PE1-E6E7, was immortalized successfully, whereas 2 other lines, PE3-E6E7 and PE4-E6E7, could not be maintained beyond crisis. Before crisis, the majority of cells in

Yuesheng Jin; Hui-chen Feng; Wen Deng; Hao Zhang; Mei Lv; Charlotte Jin; Sai Wah Tsao; Yok-Lam Kwong

2005-01-01

209

The Meq oncoprotein of Marek's disease virus interacts with p53 and inhibits its transcriptional and apoptotic activities  

PubMed Central

Background Marek's disease virus (MDV) is an oncogenic herpesvirus, which causes malignant lymphoma in chickens. The Meq protein of MDV, which is expressed abundantly in MDV-infected cells and in Marek's disease (MD) tumor cells, functions as a transcriptional activator and has been proposed to play an important role in oncogenic transformation. Preliminary studies demonstrated that Meq is able to bind p53 in vitro, as demonstrated using a protein-binding assay. This observation prompted us to examine whether the interaction between Meq and p53 occurs in cells, and to investigate the biological significance of this interaction. Results We confirmed first that Meq interacted directly with p53 using a yeast two-hybrid assay and an immunoprecipitation assay, and we investigated the biological significance of this interaction subsequently. Exogenous expression of Meq resulted in the inhibition of p53-mediated transcriptional activity and apoptosis, as analyzed using a p53 luciferase reporter assay and a TUNEL assay. The inhibitory effect of Meq on transcriptional activity mediated by p53 was dependent on the physical interaction between these two proteins, because a Meq deletion mutant that lacked the p53-binding region lost the ability to inhibit p53-mediated transcriptional activity and apoptosis. The Meq variants L-Meq and S-Meq, but not VS-Meq and ?Meq, which were expressed in MD tumor cells and MDV-infected cells, exerted an inhibitory effect on p53 transcriptional activity. In addition, ?Meq was found to act as a negative regulator of Meq. Conclusions The Meq oncoprotein interacts directly with p53 and inhibits p53-mediated transcriptional activity and apoptosis. These findings provide valuable insight into the molecular basis for the function of Meq in MDV oncogenesis. PMID:21110861

2010-01-01

210

Genetic variability of HPV-58 E6 and E7 genes in Southwest China.  

PubMed

HPV accounts for most of incidence of cervical cancer. Genetic variations of E6 and E7 may be associated with the development of cervical cancer in specific geographic regions. HPV-58 has been found to be a relatively prevalent high-risk HPV among southwest Chinese women. To explore gene intratypic variations and polymorphisms of HPV-58 E6 and E7 genes originating in Southwest China, a total of 2000 scraped cell samples were collected for DNA extraction and HPV typing. Then, the E6 and E7 genes of HPV-58 (n=22) were sequenced and compared to others submitted to GenBank, followed by an analysis of the diversity of secondary structure by DNASTAR software. Phylogenetic trees were then constructed by Neighbor-Joining and the Kimura 2-parameters methods, followed by an analysis of selection pressures acting on the E6/E7 genes by PAML software. 22 were HPV-58 positive among 215 high-risk types' samples. The nucleotide variation rate of E6 was 86.36% (19/22) among the 22 HPV-58 E6 sequences studied. 4 single nucleotide changes were identified among the E6 sequences with 3/4 synonymous mutations (C187T, A260C, C307T) and 1/4 non-synonymous mutations (A388C, from Lys to Asn, in alpha helix). The most common mutations of E6 genes are the C307T and A388C. 8 single nucleotide changes were identified among the HPV-58 E7 sequences with 2/8 synonymous mutations (T726C, T744G) and 6/8 non-synonymous mutations (G599A, C632T, G694A, G760A, G761A, T803C). The nucleotide variation rate of E7 was 72.73% (17/22). The most common mutations of E7 genes are C632T, G694A, T744G, G760A (from Gly to Ser, in turn), G761A and T803C. The phylogenetic analyses demonstrate that all HPV-58 E6/E7 variants identified belonged to the Southeast Asia lineage. There was no evidence of positive selection in the sequence alignment of HPV-58 E6 and E7 genes. PMID:24368255

Yang, Lijuan; Yang, Hongying; Chen, Junying; Huang, Xinwei; Pan, Yue; Li, Duo; Ding, Xiaojie; Wu, Kun; Shi, Xinan; Fu, Juanjuan; Shi, Haijing; Ma, Shaohui; Sun, Qiangming

2014-01-01

211

Targeting and retention of HPV16 E7 to the endoplasmic reticulum enhances immune tumour protection  

PubMed Central

Abstract The endoplasmic reticulum (ER) is where the major histocompatibility complex (MHC) class I molecules are loaded with epitopes to cause an immune cellular response. Most of the protein antigens are degraded in the cytoplasm to amino acids and few epitopes reach the ER. Antigen targeting of this organelle by Calreticulin (CRT) fusion avoids this degradation and enhances the immune response. We constructed a recombinant adenovirus to express the E7 antigen with an ER-targeting signal peptide (SP) plus an ER retention signal (KDEL sequence). In cell-culture experiments we demonstrated that this new E7 antigen, SP-E7-KDEL, targeted the ER. Infection of mice with this recombinant adenovirus that expresses SP-E7-KDEL showed interferon induction and tumour-protection response, similar to that provided by an adenovirus expressing the E7 antigen fused to CRT. This work demonstrated that just by adding a SP and the KDEL sequence, antigens can be targeted and retained in the ER with a consequent enhancement of immune response and tumour protection. These results will have significant clinical applications. PMID:19818090

Loera-Arias, MJ; Martínez-Pérez, AG; Barrera-Hernández, A; Ibarra-Obregón, ER; González-Saldívar, G; Martínez-Ortega, JI; Rosas-Taraco, A; Villanueva-Olivo, A; Esparza-González, SC; Villatoro-Hernandez, J; Saucedo-Cárdenas, O; Montes-de-Oca-Luna, R

2010-01-01

212

Methionine adenosyltransferase II serves as a transcriptional corepressor of Maf oncoprotein.  

PubMed

Protein methylation pathways comprise methionine adenosyltransferase (MAT), which produces S-adenosylmethionine (SAM) and SAM-dependent substrate-specific methyltransferases. However, the function of MAT in the nucleus is largely unknown. MafK represses or activates expression of heme oxygenase-1 (HO-1) gene, depending on its heterodimer partners. Proteomics analysis of MafK revealed its interaction with MATII?, a MAT isozyme. MATII? was localized in nuclei and found to form a dense network with chromatin-related proteins including Swi/Snf and NuRD complexes. MATII? was recruited to Maf recognition element (MARE) at HO-1 gene. When MATII? was knocked down in murine hepatoma cell line, expression of HO-1 was derepressed at both basal and induced levels. The catalytic activity of MATII?, as well as its interacting factors such as MATII?, BAF53a, CHD4, and PARP1, was required for HO-1 repression. MATII serves as a transcriptional corepressor of MafK by interacting with chromatin regulators and supplying SAM for methyltransferases. PMID:21362551

Katoh, Yasutake; Ikura, Tsuyoshi; Hoshikawa, Yutaka; Tashiro, Satoshi; Ito, Takashi; Ohta, Mineto; Kera, Yohei; Noda, Tetsuo; Igarashi, Kazuhiko

2011-03-01

213

Radiosensitization of Oropharyngeal Squamous Cell Carcinoma Cells by Human Papillomavirus 16 Oncoprotein E6*I  

SciTech Connect

Purpose: Patients with oropharyngeal squamous cell carcinoma (OSCC) whose disease is associated with high-risk human papillomavirus (HPV) infection have a significantly better outcome than those with HPV-negative disease, but the reasons for the better outcome are not known. We postulated that they might relate to an ability of HPV proteins to confer a better response to radiotherapy, a commonly used treatment for OSCC. Methods and Materials: We stably expressed the specific splicing-derived isoforms, E6*I and E6*II, or the entire E6 open reading frame (E6total), which gives rise to both full length and E6*I isoforms, in OSCC cell lines. Radiation resistance was measured in clonogenicity assays, p53 activity was measured using transfected reporter genes, and flow cytometry was used to analyze cell cycle and apoptosis. Results: E6*I and E6total sensitized the OSCC cells to irradiation, E6*I giving the greatest degree of radiosensitization (approximately eightfold lower surviving cell fraction at 10 Gy), whereas E6*II had no effect. In contrast to radiosensitivity, E6*I was a weaker inhibitor than E6total of tumor suppressor p53 transactivator activity in the same cells. Flow cytometric analyses showed that irradiated E6*I expressing cells had a much higher G2M:G1 ratio than control cells, indicating that, after G2, cells were diverted from the cell cycle to programmed cell death. Conclusion: This study supports a role for E6*I in the enhanced responsiveness of HPV-positive oropharyngeal carcinomas to p53-independent radiation-induced death.

Pang, Ervinna [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Infectious Diseases and Immunology, University of Sydney, NSW (Australia); Delic, Naomi C. [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Dermatology, University of Sydney, NSW (Australia); Hong, Angela; Zhang Mei [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Department of Radiation Oncology, Royal Prince Alfred Hospital, NSW (Australia); Rose, Barbara R. [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Infectious Diseases and Immunology, University of Sydney, NSW (Australia); Lyons, J. Guy, E-mail: guy.lyons@sydney.edu.a [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Dermatology, University of Sydney, NSW (Australia)

2011-03-01

214

Protein arginine methyltransferase 5 is a key regulator of the MYCN oncoprotein in neuroblastoma cells.  

PubMed

Approximately half of poor prognosis neuroblastomas (NBs) are characterized by pathognomonic MYCN gene amplification and MYCN over-expression. Here we present data showing that short-interfering RNA mediated depletion of the protein arginine methyltransferase 5 (PRMT5) in cell-lines representative of NBs with MYCN gene amplification leads to greatly impaired growth and apoptosis. Growth suppression is not apparent in the MYCN-negative SH-SY5Y NB cell-line, or in two immortalized human fibroblast cell-lines. Immunoblotting of NB cell-lines shows that high PRMT5 expression is strongly associated with MYCN-amplification (P < 0.004, Mann-Whitney U-test) and immunohistochemical analysis of primary NBs reveals that whilst PRMT5 protein is ubiquitously expressed in the cytoplasm of most cells, MYCN-amplified tumours exhibit pronounced nuclear PRMT5 staining. PRMT5 knockdown in MYCN-overexpressing cells, including the SHEP-21N cell-line with inducible MYCN expression leads to a dramatic decrease in MYCN protein and MYCN-associated cell-death in SHEP-21N cells. Quantitative gene expression analysis and cycloheximide chase experiments suggest that PRMT5 regulates MYCN at a post-transcriptional level. Reciprocal co-immunoprecipitation experiments demonstrated that endogenous PRMT5 and MYCN interact in both SK-N-BE(2)C and NGP cell lines. By using liquid chromatography - tandem mass spectrometry (LC-MS/MS) analysis of immunoprecipitated MYCN protein, we identified several potential sites of arginine dimethylation on the MYCN protein. Together our studies implicate PRMT5 in a novel mode of MYCN post-translational regulation and suggest PRMT5 plays a major role in NB tumorigenesis. Small-molecule inhibitors of PRMT5 may therefore represent a novel therapeutic strategy for neuroblastoma and other cancers driven by the MYCN oncogene. PMID:25475372

Park, Ji Hyun; Szemes, Marianna; Vieira, Gabriella Cunha; Melegh, Zsombor; Malik, Sally; Heesom, Kate J; Von Wallwitz-Freitas, Laura; Greenhough, Alexander; Brown, Keith W; Zheng, Y George; Catchpoole, Daniel; Deery, Michael J; Malik, Karim

2015-03-01

215

Protein arginine methyltransferase 5 is a key regulator of the MYCN oncoprotein in neuroblastoma cells  

PubMed Central

Approximately half of poor prognosis neuroblastomas (NBs) are characterized by pathognomonic MYCN gene amplification and MYCN over-expression. Here we present data showing that short-interfering RNA mediated depletion of the protein arginine methyltransferase 5 (PRMT5) in cell-lines representative of NBs with MYCN gene amplification leads to greatly impaired growth and apoptosis. Growth suppression is not apparent in the MYCN-negative SH-SY5Y NB cell-line, or in two immortalized human fibroblast cell-lines. Immunoblotting of NB cell-lines shows that high PRMT5 expression is strongly associated with MYCN-amplification (P < 0.004, Mann–Whitney U-test) and immunohistochemical analysis of primary NBs reveals that whilst PRMT5 protein is ubiquitously expressed in the cytoplasm of most cells, MYCN-amplified tumours exhibit pronounced nuclear PRMT5 staining. PRMT5 knockdown in MYCN-overexpressing cells, including the SHEP-21N cell-line with inducible MYCN expression leads to a dramatic decrease in MYCN protein and MYCN-associated cell-death in SHEP-21N cells. Quantitative gene expression analysis and cycloheximide chase experiments suggest that PRMT5 regulates MYCN at a post-transcriptional level. Reciprocal co-immunoprecipitation experiments demonstrated that endogenous PRMT5 and MYCN interact in both SK-N-BE(2)C and NGP cell lines. By using liquid chromatography – tandem mass spectrometry (LC-MS/MS) analysis of immunoprecipitated MYCN protein, we identified several potential sites of arginine dimethylation on the MYCN protein. Together our studies implicate PRMT5 in a novel mode of MYCN post-translational regulation and suggest PRMT5 plays a major role in NB tumorigenesis. Small-molecule inhibitors of PRMT5 may therefore represent a novel therapeutic strategy for neuroblastoma and other cancers driven by the MYCN oncogene. PMID:25475372

Park, Ji Hyun; Szemes, Marianna; Vieira, Gabriella Cunha; Melegh, Zsombor; Malik, Sally; Heesom, Kate J.; Von Wallwitz-Freitas, Laura; Greenhough, Alexander; Brown, Keith W.; Zheng, Y. George; Catchpoole, Daniel; Deery, Michael J.; Malik, Karim

2015-01-01

216

IGF signaling contributes to malignant transformation of hematopoietic progenitors by the MLL-AF9 oncoprotein.  

PubMed

Malignant transformation of normal hematopoietic progenitors is a multistep process that likely requires interaction between collaborating oncogenic signals at critical junctures. For instance, the MLL-AF9 fusion oncogene is thought to contribute to myeloid leukemogenesis by driving a hematopoietic stem cell-like "self-renewal" gene expression signature in committed myeloid progenitors. In addition, insulin-like growth factor (IGF) signaling has been implicated in self-renewal/pluripotency in hematopoietic and embryonic stem cell contexts and supports cell growth/survival by activation of downstream pathways, including phosphatidylinositol 3-kinase/Akt and Ras/Raf/extracellular signal-regulated kinase. We hypothesized that IGF signaling could be an important contributor in the process of cellular transformation and/or clonal propagation. Utilizing an MLL-AF9 mouse bone marrow transplantation model of acute myelogenous leukemia, we discovered that committed myeloid progenitor cells with genetically reduced levels of IGF1R were less susceptible to leukemogenic transformation due, at least in part, to a cell-autonomous defect in clonogenic activity. Rather unexpectedly, genetic deletion of IGF1R by inducible Cre recombinase had no effect on growth/survival of established leukemia cells. These findings suggest that IGF1R signaling contributes to transformation of normal myeloid progenitor cells, but is not required for propagation of the leukemic clone once it has become established. We also show that treatment of mouse MLL-AF9 acute myelogenous leukemia cells with BMS-536924, an IGF1R/insulin receptor-selective tyrosine kinase inhibitor, blocked cell growth, suggesting its efficacy in this model may be due to inhibition of insulin receptor and/or related tyrosine kinases, and raising the possibility that similar IGF1R inhibitors in clinical development may be acting through alternate/related pathways. PMID:22613471

Jenkins, Christopher R; Shevchuk, Olena O; Giambra, Vincenzo; Lam, Sonya H; Carboni, Joan M; Gottardis, Marco M; Holzenberger, Martin; Pollak, Michael; Humphries, R Keith; Weng, Andrew P

2012-09-01

217

Increasing the range of drug targets: interacting peptides provide leads for the development of oncoprotein inhibitors.  

PubMed

Two limiting aspects are mainly responsible for the sluggish development of new cancer drugs. They concern the chemical properties of potential drug molecules and the structural prerequisites for drug targets. The chemical properties which are being considered desirable for potential drugs are rather restrictive and mainly dictated by the rules of oral availability. Drug target structures are mostly defined as molecules which comprise binding pockets for low molecular weight compounds. These low molecular weight compounds then serve as leads for the derivation of analogs which recognize the same site and which can function as competitive or irreversibly binding inhibitors. The extension of the range of drug targets and the design of suitable lead compounds will be one of the most challenging tasks for drug developers in the future. Such auxiliary drug target structures can be found in the complex networks of interacting proteins which constitute the intracellular signal transduction cascades. The transient assembly of high molecular weight complexes, based on the specific interactions of particular domains, and usually regulated by secondary modifications, propagates extracellular signals through the cytoplasm and into the nucleus. Aberrations in the formation of protein complexes, or in the regulation of their disassembly, often trigger pathological conditions. The interference with interactions of proteins or the interactions of proteins with DNA offer new opportunities for drug discovery and development. Protein complexes which are indispensable for the growth and survival of cancer cells, proteins to which these cells are "addicted," appear most suited for such an approach. Stat3 and Survivin have been used as model proteins. Specific peptide ligands able to recognize and suppress the functions of crucial interaction surfaces of these proteins have been derived and shown to be able to induce cancer cell death. However, further technology development is required to turn such ligands into useful drugs. The technology comprises three steps: (1) the identification of a peptide ligand which specifically interacts with a crucial functional domain of a target protein, (2) the induction of a desired cellular phenotype upon intracellular interaction of the peptide ligand with its target structure and (3) the replacement of the peptide ligand with a functionally equivalent low molecular weight, drug like compound and its optimization through medicinal chemistry. PMID:22825353

Groner, Bernd; Weber, Axel; Mack, Laura

2012-01-01

218

High affinity interaction of poly(ADP-ribose) and the human DEK oncoprotein depends upon chain length†  

PubMed Central

Poly(ADP-ribose) polymerase-1 (PARP-1) is a molecular DNA damage sensor that catalyzes the synthesis of the complex biopolymer poly(ADP-ribose) [PAR] under consumption of NAD+. PAR engages in fundamental cellular processes such as DNA metabolism and transcription, and interacts non-covalently with specific binding proteins involved in DNA repair and regulation of chromatin structure. A factor implicated in DNA repair and chromatin organization is the DEK oncoprotein, an abundant and conserved constituent of metazoan chromatin, and the only member of its protein class. We have recently demonstrated that DEK, under stress conditions, is covalently modified with PAR by PARP-1, leading to a partial release of DEK into the cytoplasm. Additionally, we have also observed a non-covalent interaction between DEK and PAR, which we detail in the present work. Using sequence alignment, we identify three functional PAR-binding sites in the DEK primary sequence and confirm their functionality in PAR binding studies. Furthermore, we show that the non-covalent binding to DEK is dependent on PAR chain length as revealed by an overlay blot technique and PAR EMSA. Intriguingly, DEK promotes the formation of a defined complex with a 54mer PAR (KD=6 × 10?8 M), whereas no specific interaction is detected with a short PAR chain (18mer). In stark contrast to covalent poly(ADP-ribosyl)ation of DEK, the non-covalent interaction does not affect the overall ability of DEK to bind to DNA. Instead the non-covalent interaction interferes with subsequent DNA-dependent multimerization activities of DEK, as seen in South-Western, EMSA, topology and aggregation assays. In particular, non-covalent attachment of PAR to DEK promotes the formation of DEK-DEK complexes by competing with DNA binding. This was seen by the reduced affinity of PAR-bound DEK for DNA templates in solution. Taken together, our findings deepen the molecular understanding of the DEK-PAR interplay and support the existence of a cellular “PAR code” represented by PAR chain length. PMID:20669926

Fahrer, Jörg; Popp, Oliver; Malanga, Maria; Beneke, Sascha; Markovitz, David M.; Ferrando-May, Elisa; Bürkle, Alexander; Kappes, Ferdinand

2010-01-01

219

The E6 and E7 genes of human papilloma virus-type 16 protect primary astrocyte cultures from injury.  

PubMed

Many oncogenes are implicated in the regulation of apoptosis as well as in control of the cell cycle, and several have been shown to protect cells from injury. We tested whether the expression of human papillomavirus type 16 genes E6 and E7 could protect primary astrocytes from injury. Retroviral vectors were used to express E6, E7, or E6E7 in primary murine astrocyte cultures. Astrocytes expressing E6E7 suffered less than half the injury seen in controls after exposure to 400 microM H2O2. When we compared astrocytes expressing only E6 or E7, cells expressing E7 alone were protected to a greater extent and from more severe injury than those expressing E6. E6E7, E6 and E7 all provided protection from 30 h glucose deprivation, but again E7 provided the best protection, reducing injury to less than a third of that seen in controls. Expression of E7 alone decreases vulnerability to both hydrogen peroxide and glucose deprivation injury while E6 alone primarily decreases glucose deprivation injury. These results demonstrate that expression of human papillomavirus oncogenes can reduce the vulnerability of astrocytes to oxidative stress and nutrient deprivation. PMID:9622584

Lee, J E; Kim, C Y; Giaccia, A J; Giffard, R G

1998-06-01

220

Selective solubility of E7 components in poly (n-butylacrylate)  

NASA Astrophysics Data System (ADS)

Recently, the phase diagram of poly (n-butyl acrylate) and the nematic liquid crystal (LC) mixture E7 has revealed an anomalous behaviour that was attributed to the multicomponent nature of the LC which is made of four cyanoparaphenylenes. The anomalous emergence of a nematic phase at relatively low LC concentration above 60 ?C cannot be rationalized in terms of standard meanfield models commonly used to calculate phase diagrams of analogous systems. It was then suspected that the only possibility to explain this observation is to invoke the hypothesis of a selective solubility of the LC components with respect to the polymer. A detailed analysis of the composition of the LC within droplets as a function of the E7 concentration in the samples was made by HPLC. The corresponding measurements indicate unambiguously that E7 undergoes a phase separation in the presence of poly (n-butylacrylate) and exhibits a selective miscibility that is reminiscent of the preferential solvation phenomenon. HPLC chromatograms exhibit peaks that correspond to the four single compounds included in the E7 mixture and can precisely identify those present in the sample droplets. We find that both nature of components and composition depend upon samples under consideration. The overall analysis of data enables us to understand the anomalies revealed by the complete phase diagram obtained by polarized optical microscopy (POM).

Bedjaoui, L.; Bouchaour, T.; Benmouna, M.; Coqueret, X.; Maschke, U.

2009-11-01

221

Human papillomavirus type 16 E7 perturbs DREAM to promote cellular proliferation and mitotic gene expression.  

PubMed

The study of the small DNA tumor viruses continues to provide valuable new insights into oncogenesis and fundamental biological processes. Although much has already been revealed about how the human papillomaviruses (HPVs) can transform cells and contribute to cervical and oropharyngeal cancer, there clearly is much more to learn. In this issue of Oncogene, Pang et al., doi:10.1038/onc.2013.426, demonstrate that the high-risk HPV16 E7 oncogene can promote cellular proliferation by interacting with the DREAM (DP, RB-like, E2F and MuvB) complex at two distinct phases of the cell cycle. Consistent with earlier work, HPV16 E7 can bind to the retinoblastoma tumor suppressor (RB) family member p130 (RBL2) protein and promote its proteasome-mediated destruction thereby disrupting the DREAM complex and can prevent exit from the cell cycle into quiescence. In addition, they demonstrate that HPV16 E7 can bind to MuvB core complex in association with BMYB and FOXM1 and activate gene expression during the G2 and M phase of the cell cycle. Thus, HPV16 E7 acts to prevent exit from the cell cycle entry and promotes mitotic proliferation and may account for the high levels of FOXM1 often observed in poor-risk cervical cancers. PMID:24166507

DeCaprio, J A

2014-07-31

222

Molecular and evolutionary analysis of HPV16 E6 and E7 genes in Greek women.  

PubMed

Human papillomavirus type 16 (HPV16) non-European variants have been associated with persistent infection and cervical cancer development, while the L83V variant of the E6 gene has been correlated with the progression of cervical malignancy. The present study investigated the presence of the HPV16 L83V variant in Greek women. Molecular evolutionary analysis of the HPV16 E6 and E7 oncogenes was conducted in order to estimate the evolution of the HPV16 genome in the Greek population. The E6 L83V variant was found in 78.2?% of high- and 64.28?% of low-grade specimens. Moreover, the prototype and E6 L83V variants were both prevalent in high- and low-grade malignancies in Greek women. Selective pressure analysis of the individual amino acid residues of HPV16 sequences from the Greek population indicates that codon 83 of the E6 protein, as well as codon 85 of the E7 protein, are undergoing positive selection. Novel sequence variations were recorded within the E6 and E7 genes in cervical samples, characterized as (T350G) European variants. However, no signal of intratypic recombination event was identified within the E6-E7 region. Molecular and evolutionary analyses of HPV16 genomes from distinct geographical locations might provide valuable information about viral evolution and oncogenecity. PMID:23946477

Tsakogiannis, D; Papadopoulou, A; Kontostathi, G; Ruether, I G A; Kyriakopoulou, Z; Dimitriou, T G; Orfanoudakis, G; Markoulatos, P

2013-11-01

223

HPV16 E7 Protein and hTERT Proteins Defective for Telomere Maintenance Cooperate to Immortalize Human Keratinocytes  

PubMed Central

Previous studies have shown that wild-type human telomerase reverse transcriptase (hTERT) protein can functionally replace the human papillomavirus type 16 (HPV-16) E6 protein, which cooperates with the viral E7 protein in the immortalization of primary keratinocytes. In the current study, we made the surprising finding that catalytically inactive hTERT (hTERT-D868A), elongation-defective hTERT (hTERT-HA), and telomere recruitment-defective hTERT (hTERT N+T) also cooperate with E7 in mediating bypass of the senescence blockade and effecting cell immortalization. This suggests that hTERT has activities independent of its telomere maintenance functions that mediate transit across this restriction point. Since hTERT has been shown to have a role in gene activation, we performed microarray studies and discovered that E6, hTERT and mutant hTERT proteins altered the expression of highly overlapping sets of cellular genes. Most important, the E6 and hTERT proteins induced mRNA and protein levels of Bmi1, the core subunit of the Polycomb Group (PcG) complex 1. We show further that Bmi1 substitutes for E6 or hTERT in cell immortalization. Finally, tissue array studies demonstrated that expression of Bmi1 increased with the severity of cervical dysplasia, suggesting a potential role in the progression of cervical cancer. Together, these data demonstrate that hTERT has extra-telomeric activities that facilitate cell immortalization and that its induction of Bmi1 is one potential mechanism for mediating this activity. PMID:23592995

Miller, Jonathan; Dakic, Aleksandra; Chen, Renxiang; Palechor-Ceron, Nancy; Dai, Yuhai; Kallakury, Bhaskar; Schlegel, Richard; Liu, Xuefeng

2013-01-01

224

A new E6/P63 pathway, together with a strong E7/E2F mitotic pathway, modulates the transcriptome in cervical cancer cells.  

PubMed

Cervical carcinoma is associated with certain types of human papillomaviruses expressing the E6 and E7 oncogenes, which are involved in carcinogenesis through their interactions with the p53 and pRB pathways, respectively. A critical event on the path to malignant transformation is often manifested by the loss of expression of the viral E2 transcription factor due to the integration into the host genome of the viral DNA. Using microarrays, we have previously shown that reintroduction of a functional E2 in the HeLa cervical carcinoma cell line activates a cluster of p53 target genes while at the same time severely repressing a group of E2F target genes. In the present study, using new high-density microarrays containing more than 22,000 human cDNA sequences, we identified a novel p63 pathway among E2-activated genes and 38 new mitotic genes repressed by E2. We then sought to determine the pathways through which these genes were modulated and used an approach that relies on small interfering RNA to demonstrate that the p63 target genes were activated through silencing of the E6/E6AP pathway while the mitotic genes were mainly repressed through E7 silencing. Importantly, a subset of the mitotic genes was shown to be significantly induced in biopsies of stage IV cervical cancers, which points to a prominent E7 pathway in cervical carcinoma. PMID:17582001

Teissier, Sébastien; Ben Khalifa, Youcef; Mori, Marcella; Pautier, Patricia; Desaintes, Christian; Thierry, Françoise

2007-09-01

225

Examination of the pRb-Dependent and pRb-Independent Functions of E7 In Vivo  

Microsoft Academic Search

High-risk human papillomaviruses encode two oncogenes, E6 and E7, expressed in nearly all cervical cancers. Although E7 protein is best known for its ability to inactivate the retinoblastoma tumor suppressor protein, pRb, many other activities for E7 have been proposed in in vitro studies. Herein, we describe studies that allowed us to define unambiguously the pRb-dependent and -independent activities of

Scott Balsitis; Fred Dick; Denis Lee; Linda Farrell; R. Katherine Hyde; Anne E. Griep; Nicholas Dyson; Paul F. Lambert

2005-01-01

226

Increase of human papillomavirus-16 E7-specific T helper type 1 response in peripheral blood of cervical cancer patients after radiotherapy  

PubMed Central

It has been suggested that tumour cell lysis by gamma-radiation induces a tumoral antigen release eliciting an immune response. It is not clear how a specific immune response in cervical cancer patients is developed after radiotherapy. This study is an attempt to investigate the role of the human papillomavirus type 16 (HPV-16) E7-specific T helper response before and after radiotherapy. Lymphocytes were isolated from 32 cervical cancer patients before and after radiotherapy and from 16 healthy women. They were stimulated for 12 hr with autologous HPV-16 E7-pulsed monocyte-derived dendritic cells or directly with HPV-16 E7 synthetic peptides: E751–70, E765–84 and E779–98. The cells were stained for CD4, CD69, intracellular interferon-? (IFN-?) and interleukin-4 (IL-4) cytokines and analysed by flow cytometry. A specific CD4+ CD69+ IFN-?+ immune response against HPV-16 E779–98 peptide was observed in 10 of 14 patients (71·4%) after treatment, compared with 4 of 14 (28·5%) before radiotherapy (P = 0·039); however, this response was not associated with a successful clinical response. Before treatment, 5 of 31 patients showed a HPV-16 E779–98-specific T helper type 2 (Th2) response. Interestingly, this response was significantly associated with a decrease in disease-free survival (P = 0·027). These results suggest that a Th2-type cellular response could be useful as a predictor of recurrence and poor prognosis. An increase of the HPV-specific immune response was observed after radiotherapy; however, it is not enough to control completely the disease after treatment. Our results support that the E7-specific T-cell IFN-? response in cervical cancer patients, rather than reflecting the host’s capability of controlling tumour growth, might be an indicator for disease severity. PMID:18778290

Delgado, Félix Giovanni; Martínez, Elizabeth; Céspedes, María Angélica; Bravo, María Mercedes; Navas, María Cristina; Rojas, Alba Lucía Cómbita

2009-01-01

227

Arsenic trioxide amplifies cisplatin toxicity in human tubular cells transformed by HPV-16 E6/E7 for further therapeutic directions in renal cell carcinoma.  

PubMed

Human papillomavirus (HPV) DNA integrations may affect therapeutic responses in cancers through ATM network-related DNA damage response (DDR). We studied whether cisplatin-induced DDR was altered in human HK-2 renal tubular cells immortalized by HPV16 E6/E7 genes. Cytotoxicity assays utilized thiazolyl blue dye and DDR was identified by gene expression differences, double-strand DNA breaks, ATM promoter activity, and analysis of cell cycling and side population cells. After cisplatin, HK-2 cells showed greater ATM promoter activity indicating activation of this network, but DDR was muted, since little ?H2AX was expressed, DNA strand breaks were absent and cells continued cycling. When HK-2 cells were treated with the MDM2 antagonist inducing p53, nutlin-3, or p53 transcriptional activator, tenovin-1, cell growth decreased but cisplatin toxicity was unaffected. By contrast, arsenic trioxide, which by inhibiting wild-type p53-induced phosphatase-1 that serves responses downstream of p53, and by depolymerizing tubulin, synergistically enhanced cisplatin cytotoxicity including loss of SP cells. Our findings demonstrated that HPV16 E6/E7 altered DDR through p53-mediated cell growth controls, which may be overcome by targeting of WIP1 and other processes, and thus should be relevant for treating renal cell carcinoma. PMID:25444910

Dogra, Samriti; Bandi, Sriram; Viswanathan, Preeti; Gupta, Sanjeev

2015-01-28

228

Oncoprotein protein kinase  

DOEpatents

The present invention provides an isolated polynucleotide encoding a c-Jun peptide consisting of about amino acid residues 33 to 79 as set fort in SEQ ID NO: 10 or conservative variations thereof. The invention also provides a method for producing a peptide of SEQ ID NO:1 comprising (a) culturing a host cell containing a polynucleotide encoding a c-Jun peptide consisting of about amino acid residues 33 to 79 as set forth in SEQ ID NO: 10 under conditions which allow expression of the polynucleotide; and (b) obtaining the peptide of SEQ ID NO:1.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

2002-01-29

229

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (2565 Chalcedony, San Diego, CA 92122); Hibi, Masahiko (7528 Charmant Dr., No. 418, San Diego, CA 92122); Lin, Anning (8655 Via Mallorca Dr., Apt. 93, La Jolla, CA 92093)

1997-01-01

230

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE is disclosed. The polypeptide has serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences. The method of detection of JNK is also provided. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites. 44 figs.

Karin, M.; Hibi, M.; Lin, A.

1997-02-25

231

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

1998-01-01

232

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael; Hibi, Masahiko; Lin, Anning

2004-03-16

233

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Linn, Anning (La Jolla, CA)

1996-01-01

234

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

1997-01-01

235

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael; Hibi, Masahiko; Lin, Anning; Davis, Roger; Derijard, Benoit

2005-03-08

236

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Davis, Roger; Derijard, Benoit; Karin, Michael; Hibi, Masahiko; Lin, Anning

2005-01-25

237

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD or 55 kD as determined by reducing SDS-PAGE, having serine and theonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

1999-01-01

238

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA); Davis, Roger (Princeton, MA); Derijard, Benoit (Shrewsbury, MA)

2003-02-04

239

Oncoprotein protein kinase  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD or 55 kD as determined by reducing SDS-PAGE, having serine and theonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Lin, Anning (La Jolla, CA)

1999-11-30

240

Human papilloma virus E6\\/E7 genes can expand the lifespan of human corneal fibroblasts  

Microsoft Academic Search

Summary  Human corneal fibroblasts were infected with a retroviral delivery vector containing the E6 and E7 genes from human Papilloma\\u000a virus type 16 in order to produce cell lines that have an expanded lifespan in culture. Morphologically, some of the trasfected\\u000a corneal fibroblast lines appeared to have the normal spindle-shape morphology of diploid fibroblasts, whereas other lines\\u000a appeared to have a

Donna M. Peters; Nathan Dowd; Curtis Brandt; Teresa Compton

1996-01-01

241

Serological response to an HPV16 E7 based therapeutic vaccine in women with high-grade cervical dysplasia  

PubMed Central

Purpose Infection with oncogenic human papillomaviruses has been linked to the development of cervical neoplasia and cancer. The exclusive expression of E7, a viral oncogene, in infected cells makes this protein an ideal target for immunotherapy. We recently reported on the results of a trial in women with cervical carcinoma-in-situ using HspE7, a protein vaccine consisting of full length HPV16 E7 linked to a heat shock protein from M. bovis. The stimulating effects of HspE7 on specific cytotoxic T lymphocytes have been demonstrated in vitro and in (pre-)clinical trials. The induction of a B-cell response by HspE7 and its association with clinical outcome is unknown, and is the purpose of this study. Experimental design We measured the serum IgG levels against HPV16 E7 and HPV16 and -18 VLPs using a multiplexed Luminex based assay in 57 women with CIS who received the HspE7 vaccine. Results Vaccination with HspE7 results in a modest, yet maintained increase in HPV16 E7 specific IgG levels. While not significant, increased HPV16 E7 IgG levels appear to be correlated with a positive therapeutic effect. Women who were previously treated for recurrent disease (by LEEP) had significantly higher HPV16 E7 IgG levels compared with subjects without recurrent disease (p=0.01). In women with recurrent disease, higher IgG levels correlated with complete pathological response. Conclusions This study suggests that IgG levels could potentially be used as a marker for response to a therapeutic vaccine. Further translational investigations of the ‘priming’ of local immune responses using extirpative procedures should be explored. PMID:19555999

Van Doorslaer, Koenraad; Reimers, Laura L.; Studentsov, Yevgeniy Y.; Einstein, Mark H.; Burk, Robert D.

2009-01-01

242

Disruption of pocket protein dream complexes by E7 proteins of different types of human papillomaviruses.  

PubMed

It has been shown that the E7 protein of the high-risk HPV-16 transforms cells in vitro and binds pRB, p107 and p130, so called pocket proteins associated in cells with DREAM proteins, while that of the low-risk HPV-6 does not transform cells and binds p130 but not pRB or p107. These facts may indicate that p130 is essential for the HPV life cycle. To gain further insight into the relationship between HPV E7 proteins and pocket protein-DREAM complexes, E7 proteins of HPVs of various risk categories were expressed via appropriate vectors in T98G cells and the levels of various pocket proteins either total or associated with DREAM were analyzed. The obtained results demonstrated that high-risk HPV-16, HPV-18 and HPV-33, low-risk HPV-1 and HPV-11, and cutaneous HPV-48 disrupted pocket protein-DREAM complexes in T98G cells to a similar extent. PMID:24294959

Nor Rashid, N; Yusof, R; Watson, R J

2013-01-01

243

An in silico appraisal of azoic and disulphide derivatives for anticancer activity against HPV E6 oncoprotein to medicate cervical cancer.  

PubMed

Cervical cancer is the second largest form of cancer to infest the leading cause of death in women worldwide. There are many causes of cancer but viruses are the most common among them. Human papillomaviruses (HPVs) are found to be the causative organism in almost 99.7% of the cases. HPV16 is the most frequent HPV type in malignant neoplastic growth in about 60% of cervical carcinoma cases. There is limited success achieved in surgical removal or by immune modulation and more effective therapies are under investigation. Observing the mortality rate we theorize a need for alternative treatment approaches and propose a blueprint of compounds with desirable properties that may lead to the development of drugs to treat HPV-associated neoplasias. E6 oncoprotein of HPV16 has a potential zinc finger domain critical for binding to E6AP, causing p53 degradation and malignancy. Some azoics and disulfides were selected depending on their affinity towards E6 zinc finger and thereby preventing E6-E6AP complex formation. Combinatorial nontoxic derivatives of these azoics and disulfides were docked and validated against the oncoprotein to inhibit E6-E6AP interaction. Among these, two compounds (E)-N-(2-amino-2-oxoethyl)-N-(4-chlorophenyl) diazene-1,2-dicarboxamide and (E)-N-(2- amino-2-methylpropyl)-N-(thiophen-2-yl)diazene-1,2-dicarboxamide showed binding affinity of -23.70, -19.53 and -5.49, -4.65 Kcal/mol respectively in FlexX and Autodock4.2. These compounds are found more effective than those of the approved E6-E6AP binding inhibitors. Pharmacophores of these compounds were generated to confirm it with pharm mapping mechanism. The study may confer the way of design of new mechanism and new compounds to treat cervical cancer. PMID:24164050

Choudhury, Arpita Das; Choudhury, Manabendra Dutta; Chetia, Pankaj; Chowdhury, Abhishek; Talukdar, Anupam Das

2014-01-01

244

Tyrosine B10 triggers a heme propionate hydrogen bonding network loop with glutamine E7 moiety  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer H-bonding network loop by PheB10Tyr mutation is proposed. Black-Right-Pointing-Pointer The propionate group H-bonding network restricted the flexibility of the heme. Black-Right-Pointing-Pointer The hydrogen bonding interaction modulates the electron density of the iron. Black-Right-Pointing-Pointer Propionate H-bonding network loop explains the heme-ligand stabilization. -- Abstract: Propionates, as peripheral groups of the heme active center in hemeproteins have been described to contribute in the modulation of heme reactivity and ligand selection. These electronic characteristics prompted the question of whether the presence of hydrogen bonding networks between propionates and distal amino acids present in the heme ligand moiety can modulate physiological relevant events, like ligand binding association and dissociation activities. Here, the role of these networks was evaluated by NMR spectroscopy using the hemoglobin I PheB10Tyr mutant from Lucina pectinata as model for TyrB10 and GlnE7 hemeproteins. {sup 1}H-NMR results for the rHbICN PheB10Tyr derivative showed chemical shifts of TyrB10 OH{eta} at 31.00 ppm, GlnE7 N{sub {epsilon}1}H/N{sub {epsilon}2}H at 10.66 ppm/-3.27 ppm, and PheE11 C{sub {delta}}H at 11.75 ppm, indicating the presence of a crowded, collapsed, and constrained distal pocket. Strong dipolar contacts and inter-residues crosspeaks between GlnE7/6-propionate group, GlnE7/TyrB10 and TyrB10/CN suggest that this hydrogen bonding network loop between GlnE7, TyrB10, 6-propionate group, and the heme ligand contribute significantly to the modulation of the heme iron electron density as well as the ligand stabilization mechanism. Therefore, the network loop presented here support the fact that the electron withdrawing character of the hydrogen bonding is controlled by the interaction of the propionates and the nearby electronic environments contributing to the modulation of the heme electron density state. Thus, we hypothesize that in hemeproteins with similar electrostatic environment the flexibility of the heme-6-propionate promotes a hydrogen bonding network loop between the 6-propionate, the heme ligand and nearby amino acids, tailoring in this way the electron density in the heme-ligand moiety.

Ramos-Santana, Brenda J., E-mail: brenda.ramos@upr.edu [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico); Lopez-Garriga, Juan, E-mail: juan.lopez16@upr.edu [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico)] [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico)

2012-08-10

245

Lack of the canonical pRB-binding domain in the E7 ORF of artiodactyl papillomaviruses  

E-print Network

Lack of the canonical pRB-binding domain in the E7 ORF of artiodactyl papillomaviruses of papillomavirus (PV) E7 proteins has been implicated in the immortalization and transformation of the host cell. However, sequencing of the complete genomes of bovine papillomavirus type 3 (BPV-3), bovine papillomavirus

DeSalle, Rob

246

The E6AP Binding Pocket of the HPV16 E6 Oncoprotein Provides a Docking Site for a Small Inhibitory Peptide Unrelated to E6AP, Indicating Druggability of E6  

PubMed Central

The HPV E6 oncoprotein maintains the malignant phenotype of HPV-positive cancer cells and represents an attractive therapeutic target. E6 forms a complex with the cellular E6AP ubiquitin ligase, ultimately leading to p53 degradation. The recently elucidated x-ray structure of a HPV16 E6/E6AP complex showed that HPV16 E6 forms a distinct binding pocket for E6AP. This discovery raises the question whether the E6AP binding pocket is druggable, i. e. whether it provides a docking site for functional E6 inhibitors. To address these issues, we performed a detailed analysis of the HPV16 E6 interactions with two small peptides: (i) E6APpep, corresponding to the E6 binding domain of E6AP, and (ii) pep11**, a peptide that binds to HPV16 E6 and, in contrast to E6APpep, induces apoptosis, specifically in HPV16-positive cancer cells. Surface plasmon resonance, NMR chemical shift perturbation, and mammalian two-hybrid analyses coupled to mutagenesis indicate that E6APpep contacts HPV16 E6 amino acid residues within the E6AP pocket, both in vitro and intracellularly. Many of these amino acids were also important for binding to pep11**, suggesting that the binding sites for the two peptides on HPV16 E6 overlap. Yet, few E6 amino acids were differentially involved which may contribute to the higher binding affinity of pep11**. Data from the HPV16 E6/pep11** interaction allowed the rational design of single amino acid exchanges in HPV18 and HPV31 E6 that enabled their binding to pep11**. Taken together, these results suggest that E6 molecular surfaces mediating E6APpep binding can also accommodate pro-apoptotic peptides that belong to different sequence families. As proof of concept, this study provides the first experimental evidence that the E6AP binding pocket is druggable, opening new possibilities for rational, structure-based drug design. PMID:25383876

Kintscher, Susanne; Reinz, Eileen; Sehr, Peter; Bulkescher, Julia; Hoppe-Seyler, Karin; Travé, Gilles; Hoppe-Seyler, Felix

2014-01-01

247

Evidence for regulation of oxidative stress by latent membrane protein 1 oncoprotein in patients with low-grade leukemic B cell lymphoma with latent Epstein-Barr virus infection.  

PubMed

The role of latent Epstein-Barr virus (EBV) infection in the pathogenesis of low-grade B cell non-Hodgkin lymphoma (B-NHL) has not been studied. We therefore investigated the incidence of latent EBV infection in a group of patients with leukemic low-grade B-NHL, as well as the incidence of viral latent membrane protein 1 (LMP1) oncoprotein expression in the same patient group. Furthermore, in an attempt to elucidate the role of this viral oncoprotein in non-EBV-related lymphomas, we correlated the expression of LMP1 with the level of oxidative stress, a parameter related to apoptosis. In the present study we detected lower levels of oxidative stress in the sera of LMP1-positive patients. This possibly implies an anti-apoptotic role of this viral oncoprotein in low-grade B cell lymphomas. However, LMP1 expression status did not affect expression of the major anti-apoptotic gene BCL-2. PMID:24261679

Papadopoulou, Vasiliki; Diamantopoulos, Panagiotis T; Kontandreopoulou, Elina; Polonyfi, Katerina; Variami, Eleni; Kouzis, Panagiotis; Galanopoulos, Athanasios; Spanakis, Nikolaos; Zervakis, Konstantinos; Iliakis, Theodoros; Perrea, Despoina; Kollia, Panagoula; Vassilakopoulos, Theodoros P; Pangalis, Gerassimos A; Kyrtsonis, Christine; Vaiopoulos, George; Viniou, Nora-Athina

2014-08-01

248

Characterization of Human Ovarian Surface Epithelial Cells Immortalized by Human Papilloma Viral Oncogenes (HPV-E6E7 ORFs)  

Microsoft Academic Search

Primary human ovarian surface epithelial (HOSE) cells were immortalized by a retroviral vector (LXSN-16E6E7) expressing HPV-E6E7 open reading frames (ORF). Immortalizations of primary ovarian epithelial cells were achieved in three of three attempts. Detailed analysis was carried out in one line, HOSE 6-3, selected on the basis of its epithelial morphology. The immortalized line (HOSE 6-3) was nontumorigenic in nude

Sai-Wah Tsao; Samuel C. Mok; Edward G. Fey; Jonathan A. Fletcher; Thomas S. K. Wan; Eng-Ching Chew; Michael G. Muto; Robert C. Knapp; Ross S. Berkowitz

1995-01-01

249

Proteomic Investigation in A549 Lung Cell Line Stably Infected by HPV16E6\\/E7 Oncogenes  

Microsoft Academic Search

Background: Data have accumulated implicating the involvement of oncogenic human papillomaviruses (HPVs) in bronchial carcinogenesis. We recently described the presence of oncogenic HPV transcripts in non-small cell lung cancers. Objective: To investigate the role of oncogenic HPVs in lung carcinogenesis. Material and Methods: The lung cell line A549 stably infected with HPV16E6, HPV16E7 and HPVE6\\/E7 constructs was used to investigate

Marco Ciotti; Valeria Marzano; Laura Giuliani; Marzia Nuccetelli; Simona D’Aguanno; Barbara Azzimonti; Sergio Bernardini; Carlo Federico Perno; Andrea Urbani; Cartesio Favalli; Giorgio Federici

2009-01-01

250

Exceptional structure of the dilute A3 model: E8 and E7 RogersRamanujan identities  

E-print Network

model in a magnetic field. Here we establish directly the existence of an E8 structure in the dilute A3 diagram with tadpoles in terms of the E8 Cartan matrix. All our findings confirm the E8 and E7 structureExceptional structure of the dilute A3 model: E8 and E7 Rogers­Ramanujan identities S. Ole Warnaar

Pearce, Paul A.

251

The E7 protein of the cottontail rabbit papillomavirus immortalizes normal rabbit keratinocytes and reduces pRb levels, while E6 cooperates in immortalization but neither degrades p53 nor binds E6AP  

SciTech Connect

Human papillomaviruses (HPVs) cause cervical cancer and are associated with the development of non-melanoma skin cancer. A suitable animal model for papillomavirus-associated skin carcinogenesis is the infection of domestic rabbits with the cottontail rabbit papillomavirus (CRPV). As the immortalizing activity of CRPV genes in the natural target cells remains unknown, we investigated the properties of CRPV E6 and E7 in rabbit keratinocytes (RK) and their influence on the cell cycle. Interestingly, CRPV E7 immortalized RK after a cellular crisis but showed no such activity in human keratinocytes. Co-expressed CRPV E6 prevented cellular crisis. The HPV16 or CRPV E7 protein reduced rabbit pRb levels thereby causing rabbit p19{sup ARF} induction and accumulation of p53 without affecting cellular proliferation. Both CRPV E6 proteins failed to degrade rabbit p53 in vitro or to bind E6AP; however, p53 was still inducible by mitomycin C. In summary, CRPV E7 immortalizes rabbit keratinocytes in a species-specific manner and E6 contributes to immortalization without directly affecting p53.

Ganzenmueller, Tina; Matthaei, Markus; Muench, Peter; Scheible, Michael; Iftner, Angelika; Hiller, Thomas; Leiprecht, Natalie; Probst, Sonja; Stubenrauch, Frank [Sektion Experimentelle Virologie, Universitaetsklinikum Tuebingen, 72076 Tuebingen (Germany); Iftner, Thomas [Sektion Experimentelle Virologie, Universitaetsklinikum Tuebingen, 72076 Tuebingen (Germany)], E-mail: thomas.iftner@med.uni-tuebingen.de

2008-03-15

252

Transformation of mortal human fibroblasts and activation of a growth inhibitory pathway by the bovine papillomavirus E5 oncoprotein.  

PubMed

The 44-amino acid bovine papillomavirus E5 protein induces tumorigenic transformation of immortal rodent fibroblasts by binding to and activating the platelet-derived growth factor beta receptor (PDGFbetaR). Here E5 was expressed in mortal human diploid fibroblasts (HDFs), which lack the accumulated genetic changes that are present in immortal rodent cells. E5 induced focus formation and morphological transformation of HDFs without inducing anchorage independence or immortalization. Similar effects were observed with the v-sis and neu* oncogenes. E5-PDGFbetaR complexes were observed in the E5-expressing HDFs, as was constitutive PDGFbetaR activation, which was required for the transforming activity of E5. The E5 HDFs attained a higher saturation density than the control cells, expressing increased levels of hyperphosphorylated retinoblastoma protein at subconfluent densities. However, when these cells reached confluence, growth inhibition accompanied by dramatic down-regulation of the PDGFbetaR, and retinoblastoma protein was induced apparently by a factor secreted into the medium. This may represent a novel negative feedback mechanism controlling PDGFbetaR-induced proliferation and thereby protecting against complete transformation. PMID:10939593

Petti, L M; Ray, F A

2000-07-01

253

Effect of 60 Hz magnetic fields on the activation of hsp70 promoter in cultured INER-37 and RMA E7 cells.  

PubMed

It has been reported that 50-60 Hz magnetic fields (MF) with flux densities ranging from microtesla to millitesla are able to induce heat shock factor or heat shock proteins in various cells. In this study, we investigated the effect of 60 Hz sinusoidal MF at 8 and 80 ?T on the expression of the luciferase gene contained in a plasmid labeled as electromagnetic field-plasmid (pEMF). This gene construct contains the specific sequences previously described for the induction of hsp70 expression by MF, as well as the reporter for the luciferase gene. The pEMF vector was transfected into INER-37 and RMA E7 cell lines that were later exposed to either MF or thermal shock (TS). Cells that received the MF or TS treatments and their controls were processed according to the luciferase assay system for evaluate luciferase activity. An increased luciferase gene expression was observed in INER-37 cells exposed to MF and TS compared with controls (p < 0.05), but MF exposure had no effect on the RMA E7 cell line. PMID:20835776

Heredia-Rojas, J Antonio; Rodríguez de la Fuente, Abraham Octavio; Alcocer González, Juan Manuel; Rodríguez-Flores, Laura E; Rodríguez-Padilla, Cristina; Santoyo-Stephano, Martha A; Castañeda-Garza, Esperanza; Taméz-Guerra, Reyes S

2010-10-01

254

Interferon regulatory factor (IRF)-2 activates the HPV-16 E6-E7 promoter in keratinocytes.  

PubMed

Interferon regulatory factors (IRFs) are critical mediators of gene expression, cell growth and immune responses. We previously demonstrated that interferon (IFN) induction of early viral transcription and replication in several mucosal HPVs requires IRF-1 binding to a conserved interferon response element (IRE). Here we show that the IRF-2 protein serves as a baseline transactivator of the HPV-16 major early promoter, P97. Cotransfections in IRF knockout cells confirmed that basal HPV-16 promoter activity was supported by both IRF-1 and IRF-2 complexes interacting with the promoter-proximal IRE in a dose-dependent manner. Furthermore, HPV-16 E7 expression downregulates the IRF-2 promoter, thus linking IRF-2 levels to viral transforming gene expression through a negative feedback mechanism. Taken together, these observations reveal a complex viral strategy utilizing multiple signal transduction pathways during the establishment and maintenance of HPV persistence. PMID:20129639

Lace, Michael J; Anson, James R; Haugen, Thomas H; Turek, Lubomir P

2010-04-10

255

The ErbB-2/HER2 oncoprotein of human carcinomas may function solely as a shared coreceptor for multiple stroma-derived growth factors  

PubMed Central

The erbB-2/HER2 oncogene is overexpressed in a significant fraction of human carcinomas of the breast, ovary, and lung in a manner that correlates with poor prognosis. Although the encoded protein resembles several receptors for growth factors, no high affinity ligand of ErbB-2 has so far been fully characterized. However, several lines of evidence have raised the possibility that ErbB-2 can augment signal transduction initiated by binding of certain growth factors to their direct receptors. Here, we contrasted these two models of ErbB-2 function: First, examination of a large series of epidermal growth factor (EGF)-like ligands and neuregulins, including virus-encoded ligands as well as related motifs derived from the precursor of EGF, failed to detect interactions with ErbB-2 when this protein was singly expressed. Second, by using antibodies that block inter-ErbB interactions and cells devoid of surface ErbB-2, we learned that signaling by all ligands examined, except those derived from the precursor of EGF, was enhanced by the oncoprotein. These results imply that ErbB-2 evolved as a shared receptor subunit of all ErbB-specific growth factors. Thus, oncogenicity of ErbB-2 in human epithelia may not rely on the existence of a specific ligand but rather on its ability to act as a coreceptor for multiple stroma-derived growth factors. PMID:10220407

Klapper, Leah N.; Glathe, Stefanie; Vaisman, Nora; Hynes, Nancy E.; Andrews, Glenn C.; Sela, Michael; Yarden, Yosef

1999-01-01

256

E6* oncoprotein expression of human papillomavirus type-16 determines different ultraviolet sensitivity related to glutathione and glutathione peroxidase antioxidant defence.  

PubMed

Clinical observations of non-melanoma skin cancer in immunocompromised patients, such as organ transplant recipients, suggest co-operative effects of human papillomavirus (HPV) and ultraviolet (UV) radiation. The aim of the present study is to evaluate UV sensitivity and DNA damage formation according to antioxidant status in HPV16-infected keratinocytes. We used SKv cell lines, infected with HPV16 and well characterized for their proliferative and tumorigenic capacities. We showed that SKv cell lines presented various E6* (a truncated form of E6) RNA levels. We demonstrated that the higher oncoprotein RNA expression level was associated with a higher resistance to solar-simulated radiation, more specifically to UVB radiation and to hydrogen peroxide. Moreover, this high resistance was associated with a low oxidative DNA damage formation after UV radiation and was related to high glutathione content and glutathione peroxidase activities. Therefore, the results of our study suggest that E6* levels could modulate the glutathione/glutathione peroxidase pathway providing a mechanism to protect HPV-infected keratinocytes against an environmental oxidative stress, such as UV radiation. PMID:15885075

Mouret, Stéphane; Sauvaigo, Sylvie; Peinnequin, André; Favier, Alain; Beani, Jean-Claude; Leccia, Marie-Thérèse

2005-06-01

257

The transcription elongation factor ELL2 is specifically upregulated in HTLV-1-infected T-cells and is dependent on the viral oncoprotein Tax.  

PubMed

The oncoprotein Tax of human T-cell leukemia virus type 1 (HTLV-1) is a potent transactivator of viral and cellular transcription. Here, we identified ELL2 as the sole transcription elongation factor to be specifically upregulated in HTLV-1-/Tax-transformed T-cells. Tax contributes to regulation of ELL2, since transient transfection of Tax increases ELL2 mRNA, Tax transactivates the ELL2 promoter, and repression of Tax results in decrease of ELL2 in transformed T-lymphocytes. However, we also measured upregulation of ELL2 in HTLV-1-transformed cells exhibiting undetectable amounts of Tax, suggesting that ELL2 can still be maintained independent of continuous Tax expression. We further show that Tax and ELL2 synergistically activate the HTLV-1 promoter, indicating that ELL2 cooperates with Tax in viral transactivation. This is supported by our findings that Tax and ELL2 accumulate in nuclear fractions and that they co-precipitate upon co-expression in transiently-transfected cells. Thus, upregulation of ELL2 could contribute to HTLV-1 gene regulation. PMID:25058508

Mann, Melanie C; Strobel, Sarah; Fleckenstein, Bernhard; Kress, Andrea K

2014-09-01

258

Induction of antitumor immunity in vivo following delivery of a novel HPV16 DNA vaccine encoding an E6\\/E7 fusion antigen  

Microsoft Academic Search

Human papillomavirus type 16 (HPV-16) infection is associated with a majority of cervical cancers and a significant proportion of head and neck cancers. Here, we describe a novel-engineered DNA vaccine that encodes a HPV-16 consensus E6\\/E7 fusion gene (pConE6E7) with the goal of increasing its antitumor cellular immunity. Compared to an early stage HPV-16 E7 DNA vaccine (pE7), this construct

Jian Yan; Dawn K. Reichenbach; Natasha Corbitt; David A. Hokey; Mathura P. Ramanathan; Kibwei A. McKinney; David B. Weiner; Duane Sewell

2009-01-01

259

Target genes downregulated by the BCL-6/LAZ3 oncoprotein in mouse Ba/F3 cells.  

PubMed

The BCL-6/LAZ3 gene encodes a zinc-finger transcriptional repressor and is located at the breakpoint of the 3q27-associated translocations that occur most frequently in non-Hodgkin's lymphomas (NHLs). A number of chromosomal translocations involving BCL-6 have been analyzed, but the biological functions of this protein remain obscure. To examine cell responses and target genes related to the BCL-6 signaling pathway, we established Ba/F3 pro-B cells carrying a human BCL-6 transgene that is inducible under control of the lactose operon. Using a cDNA array hybridization technique, we found that the induced BCL-6 protein can downregulate the expressions of the genes, cyclin A2, chemokine receptor CXCR4, and insulin-like growth factor binding protein-4 (IGFBP-4) in the Ba/F3 cells. Northern blot analysis established that the expressions of these genes were indeed downregulated by the induced BCL-6 protein but in a somewhat different manner. The induced BCL-6 protein also inhibited cell proliferation of Ba/F3 cells. These findings strongly suggest that three key genes, namely cyclin A2, CXCR4, and IGFBP-4 may play a role in the downstream of the BCL-6 signaling pathway during B-lymphoid differentiation. PMID:11341761

Hosokawa, Y; Maeda, Y; Seto, M

2001-05-11

260

Geographical distribution and oncogenic risk association of human papillomavirus type 58 E6 and E7 sequence variations  

PubMed Central

Human papillomavirus (HPV) 58 accounts for a notable proportion of cervical cancers in East Asia and parts of Latin America, but it is uncommon elsewhere. The reason for such ethnogeographical predilection is unknown. In our study, nucleotide sequences of E6 and E7 genes of 401 HPV58 isolates collected from 15 countries/cities across four continents were examined. Phylogenetic relationship, geographical distribution and risk association of nucleotide sequence variations were analyzed. We found that the E6 genes of HPV58 variants were more conserved than E7. Thus, E6 is a more appropriate target for type-specific detection, whereas E7 is more appropriate for strain differentiation. The frequency of sequence variation varied geographically. Africa had significantly more isolates with E6-367A (D86E) but significantly less isolates with E6-203G, -245G, -367C (prototype-like) than other regions (p ? 0.003). E7-632T, -760A (T20I, G63S) was more frequently found in Asia, and E7-793G (T74A) was more frequent in Africa (p < 0.001). Variants with T20I and G63S substitutions at E7 conferred a significantly higher risk for cervical intraepithelial neoplasia grade III and invasive cervical cancer compared to other HPV58 variants (odds ratio = 4.44, p = 0.007). In conclusion, T20I and/or G63S substitution(s) at E7 of HPV58 is/are associated with a higher risk for cervical neoplasia. These substitutions are more commonly found in Asia and the Americas, which may account for the higher disease attribution of HPV58 in these areas. PMID:23136059

Chan, Paul K.S.; Zhang, Chuqing; Park, Jong-Sup; Smith-McCune, Karen K.; Palefsky, Joel M.; Giovannelli, Lucia; Coutlée, Francois; Hibbitts, Samantha; Konno, Ryo; Settheetham-Ishida, Wannapa; Chu, Tang-Yuan; Ferrera, Annabelle; Picconi, María Alejandra; De Marco, Federico; Woo, Yin-Ling; Raiol, Tainá; Piña-Sánchez, Patricia; Bae, Jeong-Hoon; Wong, Martin C.S.; Chirenje, Mike Z.; Magure, Tsitsi; Moscicki, Anna-Barbara; Fiander, Alison N.; Capra, Giuseppina; Ki, Eun Young; Tan, Yi; Chen, Zigui; Burk, Robert D.; Chan, Martin C.W.; Cheung, Tak-Hong; Pim, David; Banks, Lawrence

2014-01-01

261

Geographical distribution and oncogenic risk association of human papillomavirus type 58 E6 and E7 sequence variations.  

PubMed

Human papillomavirus (HPV) 58 accounts for a notable proportion of cervical cancers in East Asia and parts of Latin America, but it is uncommon elsewhere. The reason for such ethnogeographical predilection is unknown. In our study, nucleotide sequences of E6 and E7 genes of 401 HPV58 isolates collected from 15 countries/cities across four continents were examined. Phylogenetic relationship, geographical distribution and risk association of nucleotide sequence variations were analyzed. We found that the E6 genes of HPV58 variants were more conserved than E7. Thus, E6 is a more appropriate target for type-specific detection, whereas E7 is more appropriate for strain differentiation. The frequency of sequence variation varied geographically. Africa had significantly more isolates with E6-367A (D86E) but significantly less isolates with E6-203G, -245G, -367C (prototype-like) than other regions (p ? 0.003). E7-632T, -760A (T20I, G63S) was more frequently found in Asia, and E7-793G (T74A) was more frequent in Africa (p < 0.001). Variants with T20I and G63S substitutions at E7 conferred a significantly higher risk for cervical intraepithelial neoplasia grade III and invasive cervical cancer compared to other HPV58 variants (odds ratio = 4.44, p = 0.007). In conclusion, T20I and/or G63S substitution(s) at E7 of HPV58 is/are associated with a higher risk for cervical neoplasia. These substitutions are more commonly found in Asia and the Americas, which may account for the higher disease attribution of HPV58 in these areas. PMID:23136059

Chan, Paul K S; Zhang, Chuqing; Park, Jong-Sup; Smith-McCune, Karen K; Palefsky, Joel M; Giovannelli, Lucia; Coutlée, Francois; Hibbitts, Samantha; Konno, Ryo; Settheetham-Ishida, Wannapa; Chu, Tang-Yuan; Ferrera, Annabelle; Alejandra Picconi, María; De Marco, Federico; Woo, Yin-Ling; Raiol, Tainá; Piña-Sánchez, Patricia; Bae, Jeong-Hoon; Wong, Martin C S; Chirenje, Mike Z; Magure, Tsitsi; Moscicki, Anna-Barbara; Fiander, Alison N; Capra, Giuseppina; Young Ki, Eun; Tan, Yi; Chen, Zigui; Burk, Robert D; Chan, Martin C W; Cheung, Tak-Hong; Pim, David; Banks, Lawrence

2013-06-01

262

Suppression of HPV E6 and E7 expression by BAF53 depletion in cervical cancer cells  

SciTech Connect

Highlights: {yields} Integration of HPV into host genome critical for activation of E6 and E7 oncogenes. {yields} BAF53 is essential for higher-order chromatin structure. {yields} BAF53 knockdown suppresses E6 and E7 from HPV integrants, but not from episomal HPVs. {yields} BAF53 knockdown decreases H3K9Ac and H4K12Ac on P105 promoter of integrated HPV 18. {yields} BAF53 knockdown restores the p53-dependent signaling pathway in HeLa and SiHa cells. -- Abstract: Deregulation of the expression of human papillomavirus (HPV) oncogenes E6 and E7 plays a pivotal role in cervical carcinogenesis because the E6 and E7 proteins neutralize p53 and Rb tumor suppressor pathways, respectively. In approximately 90% of all cervical carcinomas, HPVs are found to be integrated into the host genome. Following integration, the core-enhancer element and P105 promoter that control expression of E6 and E7 adopt a chromatin structure that is different from that of episomal HPV, and this has been proposed to contribute to activation of E6 and E7 expression. However, the molecular basis underlying this chromatin structural change remains unknown. Previously, BAF53 has been shown to be essential for the integrity of higher-order chromatin structure and interchromosomal interactions. Here, we examined whether BAF53 is required for activated expression of E6 and E7 genes. We found that BAF53 knockdown led to suppression of expression of E6 and E7 genes from HPV integrants in cervical carcinoma cell lines HeLa and SiHa. Conversely, expression of transiently transfected HPV18-LCR-Luciferase was not suppressed by BAF53 knockdown. The level of the active histone marks H3K9Ac and H4K12Ac on the P105 promoter of integrated HPV 18 was decreased in BAF53 knockdown cells. BAF53 knockdown restored the p53-dependent signaling pathway in HeLa and SiHa cells. These results suggest that activated expression of the E6 and E7 genes of integrated HPV is dependent on BAF53-dependent higher-order chromatin structure or nuclear motor activity.

Lee, Kiwon; Lee, Ah-Young [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of)] [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of); Kwon, Yunhee Kim [Department of Life and Nanopharmaceutical Science and Department of Biology, Kyunghee University, Seoul 130-701 (Korea, Republic of)] [Department of Life and Nanopharmaceutical Science and Department of Biology, Kyunghee University, Seoul 130-701 (Korea, Republic of); Kwon, Hyockman, E-mail: hmkwon@hufs.ac.kr [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of)] [Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 449-791 (Korea, Republic of)

2011-08-26

263

Velocity dispersions in galaxies. I - The E7 galaxy NGC 7332.  

NASA Technical Reports Server (NTRS)

A coude spectrum of the E7 galaxy NGC 7332 with 0.9 A-resolution from 4186 to 4364 A was obtained with the Princeton SEC vidicon television camera and the Hale telescope. Comparisons with spectra of G and K giant stars, numerically broadened for various Maxwellian velocity distributions, give a dispersion velocity in the line of sight of 160 (plus or minus 20) km/sec with the best fit at G8 III. The dispersion appears to be constant within plus or minus 35 km/sec out to 1.4 kpc. After correction for projection, the rotation curve has a slope of 0.18 km/sec per pc at the center and a velocity of 130 km/sec at 1.4 kpc where it is still increasing. For an estimated effective radius of 3.5 kpc enclosing half the light, the virial theorem gives a mass of 140 billion solar masses if the mass-to-light ratio is constant throughout the galaxy.

Morton, D. C.; Chevalier, R. A.

1972-01-01

264

The nuclear localization of low risk HPV11 E7 protein mediated by its zinc binding domain is independent of nuclear import receptors  

SciTech Connect

We investigated the nuclear import of low risk HPV11 E7 protein using 1) transfection assays in HeLa cells with EGFP fusion plasmids containing 11E7 and its domains and 2) nuclear import assays in digitonin-permeabilized HeLa cells with GST fusion proteins containing 11E7 and its domains. The EGFP-11E7 and EGFP-11cE7{sub 39-98} localized mostly to the nucleus. The GST-11E7 and GST-11cE7{sub 39-98} were imported into the nuclei in the presence of either Ran-GDP or RanG19V-GTP mutant and in the absence of nuclear import receptors. This suggests that 11E7 enters the nucleus via a Ran-dependent pathway, independent of nuclear import receptors, mediated by a nuclear localization signal located in its C-terminal domain (cNLS). This cNLS contains the zinc binding domain consisting of two copies of Cys-X-X-Cys motif. Mutagenesis of Cys residues in these motifs changed the localization of the EGFP-11cE7/-11E7 mutants to cytoplasmic, suggesting that the zinc binding domain is essential for nuclear localization of 11E7.

Piccioli, Zachary; McKee, Courtney H.; Leszczynski, Anna; Onder, Zeynep; Hannah, Erin C.; Mamoor, Shahan; Crosby, Lauren; Moroianu, Junona, E-mail: moroianu@bc.ed

2010-11-10

265

The Oncogenic MicroRNA OncomiR-21 Overexpressed during Marek's Disease Lymphomagenesis Is Transactivated by the Viral Oncoprotein Meq  

PubMed Central

Gallid herpesvirus 2 (GaHV-2) is an oncogenic herpesvirus that causes T lymphoma in chicken. GaHV-2 encodes a basic leucine zipper (bZIP) protein of the AP-1 family, Meq. Upon formation of homo- or heterodimers with c-Jun, Meq may modulate the expression of viral and cellular genes involved in lymphomagenesis. GaHV-2 also encodes viral microRNAs (miRNAs) involved in latency and apoptosis escape. However, little is known about cellular miRNA deregulation during the development of GaHV-2-associated lymphoma. We determined the cellular miRNA expression profiles of chickens infected with a very virulent strain (RB-1B) or a vaccine strain (CVI988) or noninfected. Among the most deregulated cellular miRNAs, we focused our efforts on gga-miR-21, which is upregulated during GaHV-2 infection. We mapped the gga-miR-21 promoter to the 10th intron of the TMEM49 gene and found it to be driven by AP-1- and Ets-responsive elements. We show here that the viral oncoprotein Meq binds to this promoter, thereby transactivating gga-miR-21 expression. We confirmed that this miRNA targets chicken programmed death cell 4 (PDCD4) and promotes tumor cell growth and apoptosis escape. Finally, gga-miR-21 was overexpressed only during infection with a very virulent strain (RB-1B) and not during infection with a nononcogenic strain (CVI988), providing further evidence for its role in GaHV-2 lymphomagenesis. Our data therefore suggest an additional role for Meq in GaHV-2-mediated lymphomagenesis through the induction of miR-21 expression. PMID:23055556

Stik, Grégoire; Dambrine, Ginette; Pfeffer, Sébastien

2013-01-01

266

c-MYC oncoprotein dictates transcriptional profiles of ATP-binding cassette transporter genes in chronic myelogenous leukemia CD34+ hematopoietic progenitor cells.  

PubMed

Resistance to chemotherapeutic agents remains one of the major impediments to a successful treatment of chronic myeloid leukemia (CML). Misregulation of the activity of a specific group of ATP-binding cassette transporters (ABC) is responsible for reducing the intracellular concentration of drugs in leukemic cells. Moreover, a consistent body of evidence also suggests that ABC transporters play a role in cancer progression beyond the efflux of cytotoxic drugs. Despite a large number of studies that investigated the function of the ABC transporters, little is known about the transcriptional regulation of the ABC genes. Here, we present data showing that the oncoprotein c-MYC is a direct transcriptional regulator of a large set of ABC transporters in CML. Furthermore, molecular analysis carried out in CD34+ hematopoietic cell precursors of 21 CML patients reveals that the overexpression of ABC transporters driven by c-MYC is a peculiar characteristic of the CD34+ population in CML and was not found either in the population of mononuclear cells from which they had been purified nor in CD34+ cells isolated from healthy donors. Finally, we describe how the methylation state of CpG islands may regulate the access of c-MYC to ABCG2 gene promoter, a well-studied gene associated with multidrug resistance in CML, hence, affecting its expression. Taken together, our findings support a model in which c-MYC-driven transcriptional events, combined with epigenetic mechanisms, direct and regulate the expression of ABC genes with possible implications in tumor malignancy and drug efflux in CML. PMID:21693596

Porro, Antonio; Iraci, Nunzio; Soverini, Simona; Diolaiti, Daniel; Gherardi, Samuele; Terragna, Carolina; Durante, Sandra; Valli, Emanuele; Kalebic, Thea; Bernardoni, Roberto; Perrod, Chiara; Haber, Michelle; Norris, Murray D; Baccarani, Michele; Martinelli, Giovanni; Perini, Giovanni

2011-08-01

267

Probing into the biological processes influenced by ESC factor and oncoprotein HMGA2 using iPSCs.  

PubMed

Induced pluripotent stem cells (iPSCs) are rapidly evolving into an important research tool due to their close resemblance with pluripotent embryonic stem cells (ESCs). Of particular interest at this point are iPSC applications in disease modeling and drug discovery/testing. The high mobility group AT-hook 2 (HMGA2) protein is a nonhistone chromatin factor normally expressed in ESCs and during early developmental stages. Aberrant HMGA2 expression is associated, for example, with abnormal body stature, diabetes mellitus, heart development and uterine leiomyomas. Furthermore, the protein is re-expressed in many primary tumor cells and plays an important role in metastasis. Here we used iPSC formation in conjunction with exogenous human HMGA2 expression to gain insight into biological functions of HMGA2. Gene expression profiling and gene ontology analyses showed that anatomical development and cell adhesion/differentiation processes are strongly affected by HMGA2. This could help to uncover, at the molecular level, some of the known phenotypic consequences of aberrant HMGA2 expression. Furthermore, our data showed that expression of key diabetes susceptibility genes is influenced by HMGA2, which revealed an interesting link to the recently indentified Lin28/let-7 pathway regulating mammalian glucose metabolism. Contrary to a previous report, our results indicate that HMGA2 is not involved in the regulation of telomerase gene expression. Finally, our data support a model in which tight regulation of intracellular HMGA2 levels is important both to maintain a pluripotent ESC state and to induce differentiation into certain cell lineages during later developmental stages. PMID:22547345

Morshedi, Amir; Ren, Zhonglu; Li, Jinming; Dröge, Peter

2013-08-01

268

Why there are no elliptical galaxies more flattened than E7: thirty years later  

E-print Network

Elliptical galaxies are modelled as homeoidally striated Jacobi ellipsoids where the peculiar velocity distribution is anisotropic, or equivalently as their adjoints configurations i.e. classical Jacobi ellipsoids of equal mass and axes, in real or imaginary rotation. Reasons for the coincidence of bifurcation points from axisymmetric to triaxial configurations in both the sequences, contrary to earlier findings, are presented and discussed. The effect of centrifugal support at the ends of the major equatorial axis, is briefly outlined. The existence of a lower limit to the flattening of elliptical galaxies is investigated in dealing with a number of limiting situations. More specifically, (i) elliptical galaxies are considered as isolated systems, and an allowed region within Ellipsoidland, related to the occurrence of bifurcation points from ellipsoidal to pear-shaped configurations, is shown to be consistent with observations; (ii) elliptical galaxies are considered as embedded within dark matter haloes and, under reasonable assumptions, it is shown that tidal effects from hosting haloes have little influence on the above mentioned results; (iii) dark matter haloes and embedded elliptical galaxies, idealized as a single homeoidally striated Jacobi ellipsoid, are considered in connection with the cosmological transition from expansion to relaxation, by generalizing an earlier model, and the existence of a lower limit to the flattening of relaxed (oblate-like) configurations, is established. On the other hand, no lower limit is found to the elongation of relaxed (prolate-like) configurations, and the observed lack of elliptical galaxies more elongated than E7 needs a different physical interpretation, such as the fully investigated bending instabilities.

R. Caimmi

2007-04-24

269

A G R I C U LT U R E 7 the capacity of governments to participate in and enact  

E-print Network

. LANDIS Michigan State University, East Lansing Agricultural production of food, feed, fiber, or fuelA G R I C U LT U R E 7 the capacity of governments to participate in and enact both legally binding. Agriculture plays an unusual role in biological invasions, both because it is a source of nonindigenous

Sims, Gerald K.

270

17 CFR 240.14e-7 - Unlawful tender offer practices in connection with roll-ups.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Unlawful tender offer practices in connection with roll-ups...Regulation 14e § 240.14e-7 Unlawful tender offer practices in connection with roll-ups...to receive compensation for soliciting tenders directly from security holders in...

2010-04-01

271

IAC-IIASL B3.8-E7.7 FUTURE DIRECTIONS FOR INTERNATIONAL SPACE COLLABORATION FOR EXPLORATION  

E-print Network

1 IAC- IIASL B3.8-E7.7 FUTURE DIRECTIONS FOR INTERNATIONAL SPACE COLLABORATION FOR EXPLORATION Zoe. INTRODUCTION Sustainable space exploration is a challenge that no one nation can do on its own. (Global Exploration Strategy, p.2) Space exploration is an immense undertaking, both technically and financially

de Weck, Olivier L.

272

Targeting the eIF4A RNA helicase blocks translation of the MUC1-C oncoprotein.  

PubMed

The oncogenic MUC1 C-terminal subunit (MUC1-C) subunit is aberrantly overexpressed in most human breast cancers by mechanisms that are not well understood. The present studies demonstrate that stimulation of non-malignant MCF-10A cells with epidermal growth factor (EGF) or heregulin (HRG) results in marked upregulation of MUC1-C translation. Growth factor-induced MUC1-C translation was found to be mediated by PI3K?AKT, and not by MEK?ERK1/2, signaling. We also show that activation of the mammalian target of rapamycin complex 1 (mTORC1)?ribosomal protein S6 kinase 1 (S6K1) pathway decreases tumor suppressor programmed cell death protein 4 (PDCD4), an inhibitor of the eIF4A RNA helicase, and contributes to the induction of MUC1-C translation. In concert with these results, treatment of growth factor-stimulated MCF-10A cells with the eIF4A RNA helicase inhibitors, silvestrol and CR-1-31-B, blocked increases in MUC1-C abundance. The functional significance of the increase in MUC1-C translation is supported by the demonstration that MUC1-C, in turn, forms complexes with EGF receptor (EGFR) and promotes EGFR-mediated activation of the PI3K?AKT pathway and the induction of growth. Compared with MCF-10A cells, constitutive overexpression of MUC1-C in breast cancer cells was unaffected by EGF stimulation, but was blocked by inhibiting PI3K?AKT signaling. The overexpression of MUC1-C in breast cancer cells was also inhibited by blocking eIF4A RNA helicase activity with silvestrol and CR-1-31-B. These findings indicate that EGF-induced MUC1-C expression is mediated by the PI3K?AKT pathway and the eIF4A RNA helicase, and that this response promotes EGFR signaling in an autoinductive loop. The findings also indicate that targeting the eIF4A RNA helicase is a novel approach for blocking MUC1-C overexpression in breast cancer cells. PMID:22689062

Jin, C; Rajabi, H; Rodrigo, C M; Porco, J A; Kufe, D

2013-04-25

273

HPV16 E7-Dependent Transformation Activates NHE1 through a PKA-RhoA-Iinduced Inhibition of p38alpha  

PubMed Central

Background Neoplastic transformation originates from a large number of different genetic alterations. Despite this genetic variability, a common phenotype to transformed cells is cellular alkalinization. We have previously shown in human keratinocytes and a cell line in which transformation can be turned on and followed by the inducible expression of the E7 oncogene of human papillomavirus type 16 (HPV16), that intracellular alkalinization is an early and essential physiological event driven by the up-regulation of the Na/+H+ exchanger isoform 1 (NHE1) and is necessary for the development of other transformed phenotypes and the in vivo tumor formation in nude mice. Methodology Here, we utilize these model systems to elucidate the dynamic sequence of alterations of the upstream signal transduction systems leading to the transformation-dependent activation of NHE1. Principal Findings We observe that a down-regulation of p38 MAPK activity is a fundamental step in the ability of the oncogene to transform the cell. Further, using pharmacological agents and transient transfections with dominant interfering, constitutively active, phosphorylation negative mutants and siRNA strategy to modify specific upstream signal transduction components that link HPV16 E7 oncogenic signals to up-regulation of the NHE1, we demonstrate that the stimulation of NHE1 activity is driven by an early rise in cellular cAMP resulting in the down-stream inhibition of p38 MAPK via the PKA-dependent phosphorylation of the small G-protein, RhoA, and its subsequent inhibition. Conclusions All together these data significantly improve our knowledge concerning the basic cellular alterations involved in oncogene-driven neoplastic transformation. PMID:18953413

Cardone, Rosa A.; Busco, Giovanni; Greco, Maria R.; Bellizzi, Antonia; Accardi, Rosita; Cafarelli, Antonella; Monterisi, Stefania; Carratù, Pierluigi; Casavola, Valeria; Paradiso, Angelo; Tommasino, Massimo; Reshkin, Stephan J.

2008-01-01

274

Transduction of the E6 and E7 genes of epidermodysplasia-verruciformis-associated human papillomaviruses alters human keratinocyte growth and differentiation in organotypic cultures.  

PubMed

Epidermodysplasia-verruciformis-associated human papilloma virus DNA has been detected in skin cancers, in premalignant and benign skin lesions, and in plucked hairs from immunocompetent and immunosuppressed patients. The role of epidermodysplasia-verruciformis-associated human papilloma virus in the pathogenesis of nonmelanoma skin cancer is still enigmatic. In organotypic cultures we investigated the effects of retroviral transduction of the E6 and E7 genes of epidermodysplasia-verruciformis-associated human papilloma virus types 5, 12, 15, 17, 20, and 38 on the growth and differentiation of human keratinocytes. Differentiation was disturbed to different degrees as revealed by histology and by the expression patterns of differentiation markers keratin 10 and small proline rich protein 2. Conversely, proliferating cell nuclear antigen was induced in some of the suprabasal, differentiated cells to varying extent. No unscheduled DNA synthesis was detected in these cells, however, as probed by 5'-bromo-2'-deoxyuridine incorporation. Most intriguingly, when the E6 and E7 genes of epidermodysplasia-verruciformis-associated human papilloma virus types 15 and 17 were transduced, a broadening layer of basal cells and an accelerated differentiation were observed. In addition, "papilla-like structures" comprising basal-like keratinocytes arose from the basal layer into the differentiated layers. These cells did not express the differentiation markers keratin 10 and small proline rich protein 2, but did actively replicate DNA. These observations warrant further research by using this system to elucidate the replication strategy of epidermodysplasia-verruciformis-associated human papilloma virus types in keratinocytes and to shed light on the role of these human papilloma virus types in the pathogenesis of skin cancer. PMID:11886500

Boxman, I L; Mulder, L H; Noya, F; de Waard, V; Gibbs, S; Broker, T R; ten Kate, F; Chow, L T; ter Schegget, J

2001-12-01

275

Genomic Instability and Cancer: Lessons Learned from Human Papillomaviruses  

PubMed Central

High-risk HPV E6 and E7 oncoproteins cooperate to subvert critical host cell cycle checkpoint control mechanisms in order to promote viral genome replication. This results not only in aberrant proliferation but also in host cellular changes that can promote genomic instability. The HPV-16 E7 oncoprotein was found to induce centrosome abnormalities thereby disrupting mitotic fidelity and increasing the risk for chromosome missegregation and aneuploidy. In addition, expression of the high-risk HPV E7 oncoprotein stimulates DNA replication stress as a potential source of DNA breakage and structural chromosomal instability. Proliferation of genomically unstable cells is sustained by several mechanisms including the accelerated degradation of claspin by HPV-16 E7 and the degradation of p53 by the high-risk HPV E6 oncoprotein. These results highlight the oncogenic potential of aberrant proliferation and opens new avenues for prevention of malignant progression, not only in HPV-associated cervical cancer but also in non-virally associated malignancies with disrupted cell cycle checkpoint control mechanisms. PMID:21075512

Korzeniewski, Nina; Spardy, Nicole; Duensing, Anette; Duensing, Stefan

2010-01-01

276

EVI1 oncoprotein interacts with a large and complex network of proteins and integrates signals through protein phosphorylation  

PubMed Central

Ecotropic viral integration site-1 (EVI1) is an oncogenic zinc finger transcription factor whose expression is frequently up-regulated in myeloid leukemia and epithelial cancers. To better understand the mechanisms underlying EVI1-associated disease, we sought to define the EVI1 interactome in cancer cells. By using stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomics, we could confidently assign 78 proteins as EVI1-interacting partners for FLAG-tagged EVI1. Subsequently, we showed that 22 of 27 tested interacting proteins could coimmunoprecipitate with endogenous EVI1 protein, which represented an 81.5% validation rate. Additionally, by comparing the stable isotope labeling by amino acids in cell culture (SILAC) data with high-throughput yeast two hybrid results, we showed that five of these proteins interacted directly with EVI1. Functional classification of EVI1-interacting proteins revealed associations with cellular transcription machinery; modulators of transcription; components of WNT, TGF-?, and RAS pathways; and proteins regulating DNA repair, recombination, and mitosis. We also identified EVI1 phosphorylation sites by MS analysis and showed that Ser538 and Ser858 can be phosphorylated and dephosphorylated by two EVI1 interactome proteins, casein kinase II and protein phosphatase-1?. Finally, mutations that impair EVI1 phosphorylation at these sites reduced EVI1 DNA binding through its C-terminal zinc finger domain and induced cancer cell proliferation. Collectively, these combinatorial proteomic approaches demonstrate that EVI1 interacts with large and complex networks of proteins, which integrate signals from various different signaling pathways important for oncogenesis. Comprehensive analysis of the EVI1 interactome has thus provided an important resource for dissecting the molecular mechanisms of EVI1-associated disease. PMID:23858473

Bard-Chapeau, Emilie A.; Gunaratne, Jayantha; Kumar, Pankaj; Chua, Belinda Q.; Muller, Julius; Bard, Frederic A.; Blackstock, Walter; Copeland, Neal G.; Jenkins, Nancy A.

2013-01-01

277

Human papillomavirus type 16 E6 and E 7 proteins alter NF-kB in cultured cervical epithelial cells and inhibition of NF-kB promotes cell growth and immortalization  

SciTech Connect

The NF-kB family of transcription factors regulates important biological functions including cell growth, survival and the immune response. We found that Human Papillomavirus type 16 (HPV-16) E7 and E6/E7 proteins inhibited basal and TNF-alpha-inducible NF-kB activity in human epithelial cells cultured from the cervical transformation zone, the anatomic region where most cervical cancers develop. In contrast, HPV-16 E6 regulated NF-kB in a cell type- and cell growth-dependent manner. NF-kB influenced immortalization of cervical cells by HPV16. Inhibition of NF-kB by an IkB alpha repressor mutant increased colony formation and immortalization by HPV-16. In contrast, activation of NF-kB by constitutive expression of p65 inhibited proliferation and immortalization. Our results suggest that inhibition of NF-kB by HPV-16 E6/E7 contributes to immortalization of cells from the cervical transformation zone.

Vandermark, Erik R.; Deluca, Krysta A.; Gardner, Courtney R.; Marker, Daniel F.; Schreiner, Cynthia N.; Strickland, David A.; Wilton, Katelynn M. [Department of Biology, Clarkson University, Potsdam, NY 13699-5805 (United States)] [Department of Biology, Clarkson University, Potsdam, NY 13699-5805 (United States); Mondal, Sumona [Department of Mathematics, Clarkson University, Potsdam, NY 13699-5805 (United States)] [Department of Mathematics, Clarkson University, Potsdam, NY 13699-5805 (United States); Woodworth, Craig D., E-mail: woodworth@clarkson.edu [Department of Biology, Clarkson University, Potsdam, NY 13699-5805 (United States)

2012-03-30

278

Rapid Communication The house fly aliesterase gene ( MdaE7) is not associated with insecticide resistance or P450 expression in three strains of house fly  

Microsoft Academic Search

It was recently proposed that a mutation (G137D) in the MdaE7 gene was responsible for increasing transcription of a P450 (CYP6A1) resulting in resistance to diazinon. To examine if MdaE7 had a role in resistance in other strains we sequenced a fragment (~700 bp) of the MdaE7 gene from individual flies of two insecticide susceptible and three insecticide resistant (due

J. G. Scott; L. Zhang

279

Chemokine Binding Protein vCCI Attenuates Vaccinia Virus Without Affecting the Cellular Response Elicited by Immunization with a Recombinant Vaccinia Vector Carrying the HPV16 E7 Gene  

PubMed Central

Abstract Viral CC chemokine inhibitor (vCCI) of the clone P13 vaccinia virus (VACV) strain PRAHA lacks eight amino acids in the signal peptide sequence. To study the influence of vCCI on virus biology, a virus with the vCCI gene coding for a prolonged signal sequence was prepared. We found that secreted vCCI attenuated the virus in vivo, and that it correlated with decreased levels of RANTES, eotaxin, TARC, and MDC in the blood in comparison with the parental virus. We determined the influence of vCCI on the CTL response against VACV E3(140–148) (VGPSNSPTF) and HPV16 E7(49–57) (RAHYNIVTF) H-2Db-restricted epitopes. The examination of the specific CTL response elicited by immunization with the recombinant VACV-expressing tumor-associated HPV16 E7 antigen by IFN-? ELISPOT showed that the immunogenicity of the recombinant VACV-producing secretory vCCI was similar to that of the parent virus or deletion mutant in the C23L/B29R locus. Immunization with the secretory vCCI-producing recombinant virus has a lower therapeutic anti-tumor effect against TC-1 tumors. Viral CCI downregulated the E7-specific response induced by gene gun immunization with the DNA vaccines pBSC-SigE7 LAMP and pBSC-vCCI. We also observed that the immune response against vCCI elicited by the DNA vaccine did not affect the multiplication of VACV in vivo. PMID:23035852

Gabriel, Pavel; Babiarova, Katarina; Zurkova, Kamila; Krystofova, Jitka; Hainz, Petr; Kutinova, Luda

2012-01-01

280

Primary human cervical carcinoma cells require human papillomavirus E6 and E7 expression for ongoing proliferation  

SciTech Connect

Repression of human papillomavirus (HPV) E6 and E7 oncogenes in established cervical carcinoma cell lines causes senescence due to reactivation of cellular tumor suppressor pathways. Here, we determined whether ongoing expression of HPV16 or HPV18 oncogenes is required for the proliferation of primary human cervical carcinoma cells in serum-free conditions at low passage number after isolation from patients. We used an SV40 viral vector expressing the bovine papillomavirus E2 protein to repress E6 and E7 in these cells. To enable efficient SV40 infection and E2 gene delivery, we first incubated the primary cervical cancer cells with the ganglioside GM1, a cell-surface receptor for SV40 that is limiting in these cells. Repression of HPV in primary cervical carcinoma cells caused them to undergo senescence, but the E2 protein had little effect on HPV-negative primary cells. These data suggest that E6 and E7 dependence is an inherent property of human cervical cancer cells.

Magaldi, Thomas G.; Almstead, Laura L. [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States)] [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States); Bellone, Stefania [Department of Obstetrics and Gynecology and Reproductive Sciences, Yale School of Medicine, P.O. Box 208063, New Haven, CT 06520-8063 (United States)] [Department of Obstetrics and Gynecology and Reproductive Sciences, Yale School of Medicine, P.O. Box 208063, New Haven, CT 06520-8063 (United States); Prevatt, Edward G. [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States)] [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States); Santin, Alessandro D. [Department of Obstetrics and Gynecology and Reproductive Sciences, Yale School of Medicine, P.O. Box 208063, New Haven, CT 06520-8063 (United States) [Department of Obstetrics and Gynecology and Reproductive Sciences, Yale School of Medicine, P.O. Box 208063, New Haven, CT 06520-8063 (United States); Yale Comprehensive Cancer Center, P.O. Box 208028, New Haven, CT 06520-8028 (United States); DiMaio, Daniel, E-mail: daniel.dimaio@yale.edu [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States) [Department of Genetics, Yale School of Medicine, P.O. Box 208005, New Haven, CT 06520-8005 (United States); Department of Therapeutic Radiology, Yale School of Medicine, P.O. Box 208040, New Haven, CT 06520-8040 (United States); Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, P.O. Box 208024 (United States); Yale Comprehensive Cancer Center, P.O. Box 208028, New Haven, CT 06520-8028 (United States)

2012-01-05

281

Primary human cervical carcinoma cells require human papillomavirus E6 and E7 expression for ongoing proliferation  

PubMed Central

Repression of human papillomavirus (HPV) E6 and E7 oncogenes in established cervical carcinoma cell lines causes senescence due to reactivation of cellular tumor suppressor pathways. Here, we determined whether ongoing expression of HPV16 or HPV18 oncogenes is required for the proliferation of primary human cervical carcinoma cells in serum-free conditions at low passage number after isolation from patients. We used an SV40 viral vector expressing the bovine papillomavirus E2 protein to repress E6 and E7 in these cells. To enable efficient SV40 infection and E2 gene delivery, we first incubated the primary cervical cancer cells with the ganglioside GM1, a cell-surface receptor for SV40 limiting in these cells. Repression of HPV in primary cervical carcinoma cells caused them to undergo senescence, but the E2 protein had little effect on HPV-negative primary cells. These data suggest that E6 and E7 dependence is an inherent property of human cervical cancer cells. PMID:22056390

Magaldi, Thomas G.; Almstead, Laura L.; Bellone, Stefania; Prevatt, Edward G.; Santin, Alessandro D.; DiMaio, Daniel

2011-01-01

282

Exceptional structure of the dilute A$_3$ model: E$_8$ and E$_7$ Rogers--Ramanujan identities  

E-print Network

The dilute A$_3$ lattice model in regime 2 is in the universality class of the Ising model in a magnetic field. Here we establish directly the existence of an E$_8$ structure in the dilute A$_3$ model in this regime by expressing the 1-dimensional configuration sums in terms of fermionic sums which explicitly involve the E$_8$ root system. In the thermodynamic limit, these polynomial identities yield a proof of the E$_8$ Rogers--Ramanujan identity recently conjectured by Kedem {\\em et al}. The polynomial identities also apply to regime 3, which is obtained by transforming the modular parameter by $q\\to 1/q$. In this case we find an A$_1\\times\\mbox{E}_7$ structure and prove a Rogers--Ramanujan identity of A$_1\\times\\mbox{E}_7$ type. Finally, in the critical $q\\to 1$ limit, we give some intriguing expressions for the number of $L$-step paths on the A$_3$ Dynkin diagram with tadpoles in terms of the E$_8$ Cartan matrix. All our findings confirm the E$_8$ and E$_7$ structure of the dilute A$_3$ model found recently by means of the thermodynamic Bethe Ansatz.

Ole Warnaar; Paul A. Pearce

1994-08-25

283

Oncoprotein protein kinase antibody kit  

DOEpatents

An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)

2008-12-23

284

Characterization of Immortalized Human Corneal Endothelial Cell Line using HPV 16 E6/E7 on Lyophilized Human Amniotic Membrane  

PubMed Central

Purpose To establish the immortalized human corneal endothelial cell line (IHCEn) by transducing human papilloma virus (HPV) 16 E6/E7 oncogenes, and to identify their characteristics when cultivated on a lyophilized human amniotic membrane (LAM). Methods Primary human corneal endothelial cells (PHCEn) were infected using a retroviral vector with HPV 16 E6/E7, and transformed cells were clonally selected by G418. Growth properties and characteristics of IHCEn were compared with PHCEn by cell counting and RT-PCR of VDAC3, SLC4A4, CLCN3, FGF-1, Col IV, and Na+/K+ ATPase. IHCEn were cultured on LAM. Messenger RNA expressions of VDAC3, CLCN3, and Na+/K+ ATPase, and protein expressions of Na+/K+ ATPase and Col IV in IHCEn cultivated on LAM were investigated by RT-PCR, immunofluorescence, and immunohistochemical staining, respectively. Results Successful immortalization was confirmed by stable expression of HPV 16 E6/E7 mRNA by RT-PCR, and IHCEn exhibited typical corneal endothelial morphology. Doubling time of IHCEn was 30.15±10.96 hrs. Both IHCEn and PHCEn expressed VDAC3, CLCN3, SLC4A4, FGF-1, Col IV, and Na+/K+ ATPase. IHCEn cultivated on LAM showed stronger expression of VDAC3, CLCN4, and Na+/K+ ATPase mRNA than on plastic culture dish. Immunohistochemical staining and immunofluorescence revealed the positive expression of Na+/K+ ATPase and Col IV. Conclusions IHCEn were successfully established, and LAM is a good substrate for the culture of human corneal endothelial cells. PMID:16768190

Kim, Hyun-Ju; Ryu, Yang-Hwan; Ahn, Jae-Il; Park, Jeong-Keuk

2006-01-01

285

Genetic stability of a recombinant adenovirus vaccine vector seed library expressing human papillomavirus type 16 E6 and E7 proteins  

PubMed Central

The aim of the present study was to understand the genetic stability of a master seed bank (MSB) and a working seed bank (WSB) of an adenovirus vector vaccine expressing the human papillomavirus (HPV) type 16 E6 and E7 fusion proteins (Ad-HPV16E6E7). Microscopic examination and viral infectious efficacy were used to measure the infectious titers of the Ad-HPV16E6E7 MSB and WSB. Polymerase chain reaction was used to analyze the stability of the Ad-HPV16E6E7 target gene insertion, while western blot analysis and immunofluorescence were used to assess the expression levels of the Ad-HPV16E6E7 target protein. A C57BL/6 mouse TC-1 tumor cell growth inhibition model was used to evaluate the biological effect of Ad-HPV16E6E7 administration. The infectious titers of the Ad-HPV16E6E7 MSB and WSB were 6.31×109 IU/ml and 3.0×109 IU/ml, respectively. In addition, the expression levels of the inserted target genes and target proteins were found to be stable. In the mouse TC-1 tumor inhibition analysis, when the virus titers of the Ad-HPV16E6E7 MSB and WSB were 109 IU/ml, the tumor inhibition rate was 100%, which was significantly different when compared with the control group (?2MSB=20.00 and ?2WSB=20.00; P<0.01). Therefore, the Ad-HPV16E6E7 vaccine seed bank is genetically stable and meets the requirements for vaccine development. PMID:25780403

WU, JIE; CHEN, KE-DA; GAO, MENG; CHEN, GANG; JIN, SU-FENG; ZHUANG, FANG-CHENG; WU, XIAO-HONG; JIANG, YUN-SHUI; LI, JIAN-BO

2015-01-01

286

Kinetic screening of antibody-Im7 conjugates by capture on a colicin E7 DNase domain using optical biosensors.  

PubMed

Antibody generation by phage display and related in vitro display technologies routinely yields large panels of clones detected in primary end-point screenings such as enzyme-linked immunosorbent assay (ELISA). However, for the development of clinical lead candidates, rapid determination of secondary characteristics such as kinetics and thermodynamics is of nearly equal importance. Surface plasmon resonance-based biosensors are ideal tools for carrying out such high-throughput secondary screenings, allowing preliminary but confident ranking and identification of lead clones. A key feature of these assays is the stable and reversible capture of antibody fragments from crude samples leading to high-resolution kinetic analysis of library outputs. Here we exploit the high-affinity interaction between the naturally occurring nuclease domain of E. coli colicin E7 (DNaseE7) and its cognate partner, the immunity protein 7 (Im7), to develop a ligand capture system suitable for accurate kinetic ranking of library clones. We demonstrate generic applicability for a range of antibody formats: scFv antibodies, diabodies, antigen binding fragments (Fabs), and shark V(NAR) single domain antibodies. The system is adaptable and reproducible, with comparable results achieved for both the Biacore T100 and ProteOn XPR36 array biosensors. PMID:19073134

Hosse, Ralf J; Tay, Leigh; Hattarki, Meghan K; Pontes-Braz, Luisa; Pearce, Lesley A; Nuttall, Stewart D; Dolezal, Olan

2009-02-15

287

SIAH1-induced p34SEI-1 polyubiquitination/degradation mediates p53 preferential vitamin C cytotoxicity.  

PubMed

Vitamin C is considered as an important anticancer therapeutic agent although this view is debatable. In this study, we introduce a physiological mechanism demonstrating how vitamin C exerts anticancer activity that induces cell cycle arrest and apoptosis. Our previous and current data reveal that p53 tumor suppressor is the prerequisite factor for stronger anticancer effects of vitamin C. In addition, vitamin C-mediated cancer cell cytotoxicity appears to be achieved at least partly through the downregulation of the p34SEI-1 oncoprotein. Our previous study showed that p34SEI-1 increases the survival of various types of cancer cells by inhibiting their apoptosis. Present data suggest that vitamin C treatment decreases the p34SEI-1 expression at the protein level and therefore alleviates its anti-apoptotic activity. Of note, SIAH1, E3 ubiquitin ligase, appears to be responsible for the p34SEI-1 polyubiquitination and its subsequent degradation, which is dependent on p53. In summary, vitamin C increases cancer cell death by inducing SIAH1-mediated polyubiquitination/degradation of the p34SEI-1 oncoprotein in a p53-dependent manner. PMID:25586269

Lee, Soonduck; Kim, Jinsun; Jung, Samil; Li, Chengping; Yang, Young; Kim, Keun Il; Lim, Jong-Seok; Kim, Yonghwan; Cheon, Choong-Il; Lee, Myeong-Sok

2015-03-01

288

Prevalence of HPV and variation of HPV 16/HPV 18 E6/E7 genes in cervical cancer in women in South West China.  

PubMed

Genetic variations of High-Risk HPV E6/E7 may be associated with the development of cervical cancer in specific geographic regions. Few data have been reported about the HPV prevalence and E6/E7 variants among cervical cancer patients in Southwest China. This study was designed to investigate the prevalence of HPV and E6/E7 variants of most prevalent HPV among cervical cancer patients in Southwest China. After genotyping, E6/E7 genes of most prevalent HR HPV samples were sequenced and analyzed. Phylogenetic trees were then constructed, followed by an analysis of the diversity of secondary structure and selection pressures. HPV 16 (73.8%) and HPV 18 (16.4%) are the most prevalent infection types among cervical cancer patients, followed by HPV 58, HPV 56 and HPV 59, which is different from the high HPV 58 infection rate of outpatients in this region. Eighteen single nucleotide changes were observed in HPV 16 E6 with 13/18 non-synonymous mutations (5 in beta sheet and 2 in alpha helix). Ten single nucleotide changes were identified among HPV 16 E7 with 3/10 non-synonymous mutations. Three single nucleotide changes were observed in HPV 18 E6 with one non-synonymous mutation, and only one synonymous mutation was identified in HPV 18 E7. HPV 16 E6-D25E, E7-N29S and E7-T846C (S95S) exhibited a prevalent linkage mutation. The phylogenetic tree demonstrates that European and Asian lineages were the main patterns. This study may help understand the intrinsic geographical relatedness and oncogenic potential of HR HPV and contributes further to research of diagnostic, therapeutic and therapeutic vaccine strategy. PMID:25111286

Yang, Lijuan; Yang, Hongying; Wu, Kun; Shi, Xinan; Ma, Shaohui; Sun, Qiangming

2014-11-01

289

Intron Definition and a Branch Site Adenosine at nt 385 Control RNA Splicing of HPV16 E6*I and E7 Expression  

PubMed Central

HPV16 E6 and E7, two viral oncogenes, are expressed from a single bicistronic pre-mRNA. In this report, we provide the evidence that the bicistronic pre-mRNA intron 1 contains three 5? splice sites (5? ss) and three 3? splice sites (3? ss) normally used in HPV16+ cervical cancer and its derived cell lines. The choice of two novel alternative 5? ss (nt 221 5? ss and nt 191 5? ss) produces two novel isoforms of E6E7 mRNAs (E6*V and E6*VI). The nt 226 5? ss and nt 409 3? ss is preferentially selected over the other splice sites crossing over the intron to excise a minimal length of the intron in RNA splicing. We identified AACAAAC as the preferred branch point sequence (BPS) and an adenosine at nt 385 (underlined) in the BPS as a branch site to dictate the selection of the nt 409 3? ss for E6*I splicing and E7 expression. Introduction of point mutations into the mapped BPS led to reduced U2 binding to the BPS and thereby inhibition of the second step of E6E7 splicing at the nt 409 3? ss. Importantly, the E6E7 bicistronic RNA with a mutant BPS and inefficient splicing makes little or no E7 and the resulted E6 with mutations of 91QYNK94 to 91PSFW94 displays attenuate activity on p53 degradation. Together, our data provide structural basis of the E6E7 intron 1 for better understanding of how viral E6 and E7 expression is regulated by alternative RNA splicing. This study elucidates for the first time a mapped branch point in HPV16 genome involved in viral oncogene expression. PMID:23056301

Ajiro, Masahiko; Jia, Rong; Zhang, Lifang; Liu, Xuefeng; Zheng, Zhi-Ming

2012-01-01

290

A C-terminal Hydrophobic, Solvent-protected Core and a Flexible N-terminus are Potentially Required for Human Papillomavirus 18 E7 Protein Functionality  

SciTech Connect

The oncogenic potential of the high-risk human papillomavirus (HPV) relies on the expression of genes specifying the E7 and E6 proteins. To investigate further the variation in oligomeric structure that has been reported for different E7 proteins, an HPV-18 E7 cloned from a Hispanic woman with cervical intraepithelial neoplasia was purified to homogeneity most probably as a stable monomeric protein in aqueous solution. We determined that one zinc ion is present per HPV-18 E7 monomer by amino acid and inductively coupled plasma-atomic emission spectroscopy analysis. Intrinsic fluorescence and circular dichroism spectroscopic results indicate that the zinc ion is important for the correct folding and thermal stability of HPV-18 E7. Hydroxyl radical mediated protein footprinting coupled to mass spectrometry and other biochemical and biophysical data indicate that near the C-terminus, the four cysteines of the two Cys-X{sub 2}-Cys motifs that are coordinated to the zinc ion form a solvent inaccessible core. The N-terminal LXCXE pRb binding motif region is hydroxyl radical accessible and conformationally flexible. Both factors, the relative flexibility of the pRb binding motif at the N-terminus and the C-terminal metal-binding hydrophobic solvent-protected core, combine together and facilitate the biological functions of HPV-18 E7.

Liu, S.; Tian, Y; Greenaway, F; Sun, M

2010-01-01

291

Diagnosis of 25 genotypes of human papillomaviruses for their physical statuses in cervical precancerous/cancerous lesions: a comparison of E2/E6E7 ratio-based vs. multiple E1-L1/E6E7 ratio-based detection techniques.  

PubMed

BackgroundCervical lesions caused by integrated human papillomavirus (HPV) infection are highly dangerous because they can quickly develop into invasive cancers. However, clinicians are currently hampered by the lack of a quick, convenient and precise technique to detect integrated/mixed infections of various genotypes of HPVs in the cervix. This study aimed to develop a practical tool to determine the physical status of different HPVs and evaluate its clinical significance.MethodsThe target population comprised 1162 women with an HPV infection history of¿>¿six months and an abnormal cervical cytological finding. The multiple E1-L1/E6E7 ratio analysis, a novel technique, was developed based on determining the ratios of E1/E6E7, E2/E6E7, E4E5/E6E7, L2/E6E7 and L1/E6E7 within the viral genome. Any imbalanced ratios indicate integration. Its diagnostic and predictive performances were compared with those of E2/E6E7 ratio analysis. The detection accuracy of both techniques was evaluated using the gold-standard technique ¿detection of integrated papillomavirus sequences¿ (DIPS). To realize a multigenotypic detection goal, a primer and probe library was established.ResultsThe integration rate of a particular genotype of HPV was correlated with its tumorigenic potential and women with higher lesion grades often carried lower viral loads. The E1-L1/E6E7 ratio analysis achieved 92.7% sensitivity and 99.0% specificity in detecting HPV integration, while the E2/E6E7 ratio analysis showed a much lower sensitivity (75.6%) and a similar specificity (99.3%). Interference due to episomal copies was observed in both techniques, leading to false-negative results. However, some positive results of E1-L1/E6E7 ratio analysis were missed by DIPS due to its stochastic detection nature. The E1-L1/E6E7 ratio analysis is more efficient than E2/E6E7 ratio analysis and DIPS in predicting precancerous/cancerous lesions, in which both positive predictive values (36.7%-82.3%) and negative predictive values (75.9%-100%) were highest (based on the results of three rounds of biopsies).ConclusionsThe multiple E1-L1/E6E7 ratio analysis is more sensitive and predictive than E2/E6E7 ratio analysis as a triage test for detecting HPV integration. It can effectively narrow the range of candidates for colposcopic examination and cervical biopsy, thereby lowering the expense of cervical cancer prevention. PMID:25269554

Zhang, Rong; He, Yi-Feng; Chen, Mo; Chen, Chun-Mei; Zhu, Qiu-Jing; Lu, Huan; Wei, Zhen-Hong; Li, Fang; Zhang, Xiao-Xin; Xu, Cong-Jian; Yu, Long

2014-10-01

292

Dose-dependent effects of selenite (Se(4+)) on arsenite (As(3+))-induced apoptosis and differentiation in acute promyelocytic leukemia cells.  

PubMed

To enhance the therapeutic effects and decrease the adverse effects of arsenic on the treatment of acute promyelocytic leukemia, we investigated the co-effects of selenite (Se(4+)) and arsenite (As(3+)) on the apoptosis and differentiation of NB4 cells and primary APL cells. A 1.0-?M concentration of Se(4+) prevented the cells from undergoing As(3+)-induced apoptosis by inhibiting As(3+) uptake, eliminating As(3+)-generated reactive oxygen species, and repressing the mitochondria-mediated intrinsic apoptosis pathway. However, 4.0??M Se(4+) exerted synergistic effects with As(3+) on cell apoptosis by promoting As(3+) uptake, downregulating nuclear factor-?B, and activating caspase-3. In addition to apoptosis, 1.0 and 3.2??M Se(4+) showed contrasting effects on As(3+)-induced differentiation in NB4 cells and primary APL cells. The 3.2??M Se(4+) enhanced As(3+)-induced differentiation by promoting the degradation of promyelocytic leukemia protein-retinoic acid receptor-? (PML-RAR?) oncoprotein, but 1.0??M Se(4+) did not have this effect. Based on mechanistic studies, Se(4+), which is similar to As(3+), might bind directly to Zn(2+)-binding sites of the PML RING domain, thus controlling the fate of PML-RAR? oncoprotein. PMID:25590806

Wang, S; Geng, Z; Shi, N; Li, X; Wang, Z

2015-01-01

293

Détection et quantification des infections génitales à papillomavirus humains : conséquences virologiques, épidémiologiques et cliniques  

Microsoft Academic Search

Human papillomaviruses (HPV) are the main risk factor for cervical cancer. By introducing its DNA into the genome of infected human cells, the virus expresses two oncoproteins (E6 and E7) that induce inactivation of tumour suppressors and telomerase. HPV infection is extremely common. But most of women will clear the infection over an 8–10-month period without developing any cervical lesion.

X. Carcopino; M. Henry; D. Olive; L. Boubli; C. Tamalet

2011-01-01

294

Bioactive saponins and glycosides. XXIII. Triterpene saponins with gastroprotective effect from the seeds of Camellia sinensis--theasaponins E3, E4, E5, E6, and E7.  

PubMed

The saponin fraction from the seeds of the tea plant [Camellia sinensis (L.) O. KUNTZE (Theaceae)] was found to exhibit potent protective effects on ethanol- and indomethacin-induced gastric mucosal lesions in rats. Five new triterpene saponins, theasaponins E3 (1), E4 (2), E5 (3), E6 (4), and E7 (5), were isolated together with 11 known saponins from the saponin fraction. The chemical structures of 1-5 were elucidated on the basis of chemical and physicochemical evidence. Among the isolated saponins, theasaponins E1 (6), E2 (7), and E5 (3) and assamsaponin C (10) showed an inhibitory effect on ethanol-induced gastric mucosal lesions at a dose of 5.0 mg/kg, p.o. and their activities were stronger than that of omeplazole. With regard to the structure-activity relationships of theasaponins, the following structural requirements for a protective effect on ethanol-induced gastric lesions were suggested; 1) the 21- and/or 22-acyl groups are essential for the activity, 2) acetylation of the 16-hydroxyl group reduce the activity. PMID:16327189

Yoshikawa, Masayuki; Morikawa, Toshio; Li, Ning; Nagatomo, Akifumi; Li, Xian; Matsuda, Hisashi

2005-12-01

295

Sequential treatment of HPV E6 and E7-expressing TC-1 cells with bortezomib and celecoxib promotes apoptosis through p-p38 MAPK-mediated downregulation of cyclin D1 and CDK2.  

PubMed

Interruption of the cell cycle is accompanied by changes in several related molecules that result in the activation of apoptosis. The present study was performed to verify the apoptotic effects of sequential treatment with bortezomib and celecoxib in TC-1 cells expressing the human papillomavirus (HPV) E6 and E7 proteins. In TC-1 cells sequentially treated with bortezomib and celecoxib, apoptosis was induced through decreased expression of signal transducer and activator of transcription-3 (STAT3), cyclin D1 and cyclin-dependent kinase (CDK) 2, which are major regulators of the G0/G1 cell cycle checkpoint. In addition, increased levels of p21, CHOP, BiP and p-p38 MAPK were identified in these cells. The treatment-induced apoptosis was effectively inhibited by treatment with SB203580, an inhibitor of p-p38. Moreover, the growth of tumors sequentially treated with bortezomib and celecoxib was retarded compared to the growth of tumors exposed to a single treatment with either bortezomib or celecoxib in vivo. We demonstrated that sequential treatment with bortezomib and celecoxib induced apoptosis via p-p38-mediated G0/G1 cell cycle arrest and endoplasmic reticulum (ER) stress. Sequential treatment with these two drugs could therefore be a useful therapy for cervical cancer. PMID:24627094

Kim, Jee-Eun; Lee, Ji-In; Jin, Dong-Hoon; Lee, Wang Jae; Park, Ga Bin; Kim, Seonghan; Kim, Yeong Seok; Wu, T-C; Hur, Dae Young; Kim, Daejin

2014-05-01

296

Expression of c-erbB-2, c-myc, and c-ras oncoproteins, insulin-like growth factor receptor I, and epidermal growth factor receptor in ovarian carcinoma.  

PubMed Central

AIMS--To assess whether the overexpression of five dominant oncogene encoded proteins is crucial to the pathogenesis of ovarian carcinoma and whether this provides any useful prognostic information. METHODS--The expression of the insulin-like growth factor 1 receptor (ILGFR 1), epidermal growth factor receptor (EGFR), and the c-erbB-2, c-ras, and c-myc products was studied by multiparameter flow cytometry in 80 patients with epithelial ovarian cancer for whom long term follow up was available. RESULTS--Overexpression of ILGFR 1, EGFR, c-erbB-2, c-ras and c-myc was found in, respectively, nine of 80 (11%), 10 of 80 (12%), 19 of 80 (24%), 16 of 80 (20%) and 28 of 80 (35%) ovarian carcinomas. The levels of expression of ILGFR 1, EGFR, c-erbB-2 and c-ras were significantly higher in the tumours of patients with recurrent or persistent disease after chemotherapy than in the tumours of patients at initial presentation (p < 0.02). Multivariate analysis showed that residual tumour (p < 0.001), FIGO stage (p = 0.002), EGFR overexpression (p = 0.030) and previous chemotherapy (p = 0.034) were independent variables for predicting survival. CONCLUSIONS--Overexpression of these oncoproteins only occurs in a small proportion of ovarian carcinomas but may have an important role in the progression of the disease. PMID:7962604

van Dam, P A; Vergote, I B; Lowe, D G; Watson, J V; van Damme, P; van der Auwera, J C; Shepherd, J H

1994-01-01

297

Dependence of Intracellular and Exosomal microRNAs on Viral E6/E7 Oncogene Expression in HPV-positive Tumor Cells  

PubMed Central

Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells. PMID:25760330

Honegger, Anja; Schilling, Daniela; Bastian, Sandra; Sponagel, Jasmin; Kuryshev, Vladimir; Sültmann, Holger; Scheffner, Martin; Hoppe-Seyler, Karin; Hoppe-Seyler, Felix

2015-01-01

298

Dependence of Intracellular and Exosomal microRNAs on Viral E6/E7 Oncogene Expression in HPV-positive Tumor Cells.  

PubMed

Specific types of human papillomaviruses (HPVs) cause cervical cancer. Cervical cancers exhibit aberrant cellular microRNA (miRNA) expression patterns. By genome-wide analyses, we investigate whether the intracellular and exosomal miRNA compositions of HPV-positive cancer cells are dependent on endogenous E6/E7 oncogene expression. Deep sequencing studies combined with qRT-PCR analyses show that E6/E7 silencing significantly affects ten of the 52 most abundant intracellular miRNAs in HPV18-positive HeLa cells, downregulating miR-17-5p, miR-186-5p, miR-378a-3p, miR-378f, miR-629-5p and miR-7-5p, and upregulating miR-143-3p, miR-23a-3p, miR-23b-3p and miR-27b-3p. The effects of E6/E7 silencing on miRNA levels are mainly not dependent on p53 and similarly observed in HPV16-positive SiHa cells. The E6/E7-regulated miRNAs are enriched for species involved in the control of cell proliferation, senescence and apoptosis, suggesting that they contribute to the growth of HPV-positive cancer cells. Consistently, we show that sustained E6/E7 expression is required to maintain the intracellular levels of members of the miR-17~92 cluster, which reduce expression of the anti-proliferative p21 gene in HPV-positive cancer cells. In exosomes secreted by HeLa cells, a distinct seven-miRNA-signature was identified among the most abundant miRNAs, with significant downregulation of let-7d-5p, miR-20a-5p, miR-378a-3p, miR-423-3p, miR-7-5p, miR-92a-3p and upregulation of miR-21-5p, upon E6/E7 silencing. Several of the E6/E7-dependent exosomal miRNAs have also been linked to the control of cell proliferation and apoptosis. This study represents the first global analysis of intracellular and exosomal miRNAs and shows that viral oncogene expression affects the abundance of multiple miRNAs likely contributing to the E6/E7-dependent growth of HPV-positive cancer cells. PMID:25760330

Honegger, Anja; Schilling, Daniela; Bastian, Sandra; Sponagel, Jasmin; Kuryshev, Vladimir; Sültmann, Holger; Scheffner, Martin; Hoppe-Seyler, Karin; Hoppe-Seyler, Felix

2015-03-01

299

Immortalization of Human Fetal Hepatocyte by Ectopic Expression of Human Telomerase Reverse Transcriptase, Human Papilloma Virus (E7) and Simian Virus 40 Large T (SV40 T) Antigen Towards Bioartificial Liver Support  

PubMed Central

Background Generation of genetically stable and non-tumoric immortalization cell line from primary cells would be enormously useful for research and therapeutic purposes, but progress towards this goal has so far been limited. It is now universal acceptance that immortalization of human fetal hepatocytes based on recent advances of telomerase biology and oncogene, lead to unlimited population doubling could be the possible source for bioartificial liver device. Methods Immortalization of human fetal hepatocytes cell line by ectopic expression of human telomerase reverse transcriptase (hTERT), human papilloma virus gene (E7) and simian virus 40 large T (SV40 T) antigens is main goal of present study. We used an inducible system containing human telomerase and E7, both of which are cloned into responder constructs controlled by doxycycline transactivator. We characterized the immortalized human fetal hepatocyte cells by analysis of green fluorescent cells (GFP) positive cells using flow cytometry (FACs) cell sorting and morphology, proliferative rate and antigen expression by immunohistochemical analysis. In addition to we analysized lactate formation, glucose consumption, albumin secretion and urea production of immortalized human fetal hepatocyte cells. Results After 25 attempts for transfection of adult primary hepatocytes by human telomerase and E7 to immortalize them, none of the transfection systems resulted in the production of a stable, proliferating cell line. Although the transfection efficiency was more than 70% on the first day, the vast majority of the transfected hepatocytes lost their signal within the first 5–7 days. The remaining transfected hepatocytes persisted for 2–4 weeks and divided one or two times without forming a clone. After 10 attempts of transfection human fetal hepatocytes using the same transfection system, we obtained one stable human fetal hepatocytes cell line which was able albumin secretion urea production and glucose consumption. Conclusion We established a conditional human fetal hepatocytes cell line with mesenchymal characteristics. Thus immortalization of human fetal hepatocytes cell line by telomerase biology offers a great challenge to examine basic biological mechanisms which are directly related to human and best cell source having unlimited population doubling for bioartificial support without any risk of replicative senescence and pathogenic risks. PMID:25755560

Giri, Shibashish; Bader, Augustinus

2014-01-01

300

Re: Account 2155-E7P10 -Deepwater Ojl Spill sand-berm report Rebecca J Deckard 0 Sonya A Jones 05/26/201004:34 PM  

E-print Network

Re: Account 2155-E7P10 - Deepwater Ojl Spill sand-berm report t Rebecca J Deckard 0 Sonya A Jones the report until we receive official word to do so. Rebecca J. Deckard, PSC Chief USGS EP · Raleigh PSC (AL: Cc: Date: Subject: Sonya A Jones/WRD/USGS/DOI Rebecca J DeckardiGIOIUSGSIDOI@USGS Dawn L Lavoiel

Torgersen, Christian

301

UCL CENTRE FOR ADVANCED SPATIAL ANALYSIS Centre for Advanced Spatial Analysis University College London 1 -19 Torrington Place Gower St London WC1E 7HB  

E-print Network

London 1 - 19 Torrington Place Gower St London WC1E 7HB Tel: +44 (0)20 7679 1782 casa@ucl.ac.uk www://www.gisagents.blogspot.com Centre for Advanced Spatial Analysis University College London, 1-19 Torrington Place, London, WC1E 6BT

Tesfatsion, Leigh

302

UCL CENTRE FOR ADVANCED SPATIAL ANALYSIS Centre for Advanced Spatial Analysis University College London 1 -19 Torrington Place Gower St London WC1E 7HB  

E-print Network

London 1 - 19 Torrington Place Gower St London WC1E 7HB Tel: +44 (0)20 7679 1782 casa@ucl.ac.uk www O'Brien 2 1 Department of Geography, University College London 2 Centre for Advanced Spatial Analysis (CASA), University College London Tel: +44 (0) 7679 0500, Fax +44 (0)20 7679 0565 p

Jones, Peter JS

303

Influence of chromosomal integration on glucocorticoid-regulated transcription of growth-stimulating papillomavirus genes E6 and E7 in cervical carcinoma cells  

SciTech Connect

In most cervical carcinoma cells the E6 and E7 genes of specific human papillomaviruses are transcribed from viral sequences integrated into host cell chromosomes. Glucocorticoids activate the promoter elements of various human papillomaviruses in transient-expression assays. The authors have analyzed the effect of dexamethasone on the transcription rate of human papillomaviruses 18 E6 and E7 genes integrated at different chromosomal sites in four cervical cancer cell lines. Dexamethasone led to an increase in the transcription rate of the integrated E6-E7 sequences in C4-1 and C4-2 cells but led to a decrease in SW 756 cells and did not affect the transcription rate in HeLa cells. It thus appears that dominant regulatory mechanisms presumably depending on the chromosomal integration site are able to override the response of the viral promoter to steroid hormones. The growth rate of all dexamethasone-treated cell lines correlated consistently with the expression of the papillomavirus E6 and E7 genes, supporting their role in the maintenance of the proliferative phenotype of cervical carcinoma cells. Since human papillomaviruses are integrated into the host cell genome at variable, presumably randomly selected chromosomal loci, regulatory mechanisms that influence viral gene expression, and hence cell growth, may differ among cancers of independent clonal origin.

Von Knebel Doeberitz, M.; Bauknecht, T.; Bartsch, D.; Zur Hausen, H. (Inst. fur Virusforshung/ATV, Heidelberg (West Germany))

1991-02-15

304

Honeybee venom possesses anticancer and antiviral effects by differential inhibition of HPV E6 and E7 expression on cervical cancer cell line.  

PubMed

Bee venom (BV) therapy is a type of alternative medical treatment used to treat various diseases in oriental medicine. The mechanisms underlying the effects of BV remain poorly understood. In the present study, we evaluated the antiviral effect of BV on cervical carcinoma cell lines (CaSki, HeLa, C33A and TC-1). BV treatments resulted in a more significant suppression of cell growth in HPV 16-infected cells (CaSki) and a lesser suppression in HPV 18-infected cells (HeLa). However, less suppression was observed in HPV-negative C33A cells. In 10 µg/ml BV-treated CaSki cells, the mRNA expression and protein levels of HPV16 E6 and E7 were significantly decreased by BV, while HPV18 E6 and E7 mRNA expression levels were not significantly altered by 10 µg/ml BV-treated HeLa cells. The antitumor effects of BV were in accordance with in vitro data, in restricting tumor growth in vivo and were much more effective on the suppression of tumor growth. Furthermore, the mRNA and protein expression levels of HPV16 E6 and E7 were decreased by BV in TC-1 tumors. These findings demonstrated the antiviral effects of BV in HPV-infected cervical cancer cells and the anticancer effects of BV in HPV16 E6/E7-expressed TC-1 tumors. Collectively, BV plays a differential role in suppressing HPV16-infected cells (CaSki cells) and HPV18-infected cells (HeLa cells) by the downregulation of E6/E7 protein of HPV16/18. PMID:25633640

Kim, Yong-Wan; Chaturvedi, Pankaj Kumar; Chun, Sung Nam; Lee, Yang Gu; Ahn, Woong Shick

2015-04-01

305

Influence of chromosomal integration on glucocorticoid-regulated transcription of growth-stimulating papillomavirus genes E6 and E7 in cervical carcinoma cells.  

PubMed Central

In most cervical carcinoma cells the E6 and E7 genes of specific human papillomaviruses are transcribed from viral sequences integrated into host cell chromosomes. Glucocorticoids activate the promoter elements of various human papillomaviruses in transient-expression assays. We have analyzed the effect of dexamethasone on the transcription rate of human papillomavirus 18 E6 and E7 genes integrated at different chromosomal sites in four cervical cancer cell lines. Dexamethasone led to an increase in the transcription rate of the integrated E6-E7 sequences in C4-1 and C4-2 cells but led to a decrease in SW 756 cells and did not affect the transcription rate in HeLa cells. However, when the viral promoter elements derived from HeLa or SW 756 cells, in which dexamethasone does not activate transcription of the integrated E6-E7 sequences, were tested in transient-expression assays within the same cell lines, dexamethasone consistently activated the viral promoter. It thus appears that dominant regulatory mechanisms presumably depending on the chromosomal integration site are able to override the response of the viral promoter to steroid hormones. The growth rate of all dexamethasone-treated cell lines correlated consistently with the expression of the papillomavirus E6 and E7 genes, supporting their role in the maintenance of the proliferative phenotype of cervical carcinoma cells. Since human papillomaviruses are integrated into the host cell genome at variable, presumably randomly selected chromosomal loci, regulatory mechanisms that influence viral gene expression, and hence cell growth, may differ among cancers of independent clonal origin. Images PMID:1847520

von Knebel Doeberitz, M; Bauknecht, T; Bartsch, D; zur Hausen, H

1991-01-01

306

Members of a family of JmjC domain-containing oncoproteins immortalize embryonic fibroblasts via a JmjC domain-dependent process  

Microsoft Academic Search

A common integration site, cloned from MoMuLV-induced rat T cell lymphomas, was mapped immediately upstream of Not dead yet-1 (Ndy1)\\/KDM2B, a gene expressed primarily in testis, spleen, and thymus, that is also known as FBXL10 or JHDM1B. Ndy1 encodes a nuclear, chromatin-associated protein that harbors Jumonji C (JmjC), CXXC, PHD, proline-rich, F-box, and leucine-rich repeat domains. Ndy1 and its homolog

Raymond Pfau; Alexandros Tzatsos; Sotirios C. Kampranis; Oksana B. Serebrennikova; Susan E. Bear; Philip N. Tsichlis

2008-01-01

307

Members of a family of JmjC domain-containing oncoproteins immortalize embryonic fibroblasts via a JmjC domain-dependent process.  

PubMed

A common integration site, cloned from MoMuLV-induced rat T cell lymphomas, was mapped immediately upstream of Not dead yet-1 (Ndy1)/KDM2B, a gene expressed primarily in testis, spleen, and thymus, that is also known as FBXL10 or JHDM1B. Ndy1 encodes a nuclear, chromatin-associated protein that harbors Jumonji C (JmjC), CXXC, PHD, proline-rich, F-box, and leucine-rich repeat domains. Ndy1 and its homolog Ndy2/KDM2A (FBXL11 or JHDM1A), which is also a target of provirus integration in retrovirus-induced lymphomas, encode proteins that were recently shown to possess Jumonji C-dependent histone H3 K36 dimethyl-demethylase or histone H3 K4 trimethyl-demethylase activities. Here, we show that mouse embryo fibroblasts engineered to express Ndy1 or Ndy2 undergo immortalization in the absence of replicative senescence via a JmjC domain-dependent process that targets the Rb and p53 pathways. Knockdown of endogenous Ndy1 or expression of JmjC domain mutants of Ndy1 promote senescence, suggesting that Ndy1 is a physiological inhibitor of senescence in dividing cells and that inhibition of senescence depends on histone H3 demethylation. PMID:18250326

Pfau, Raymond; Tzatsos, Alexandros; Kampranis, Sotirios C; Serebrennikova, Oksana B; Bear, Susan E; Tsichlis, Philip N

2008-02-12

308

Oncoprotein YAP Regulates the Spindle Checkpoint Activation in a Mitotic Phosphorylation-dependent Manner through Up-regulation of BubR1.  

PubMed

The transcriptional co-activator YAP (Yes-associated protein) functions as an oncogene; however, it is largely unclear how YAP exerts its oncogenic role. In this study, we further explored the functional significance of YAP and its mitotic phosphorylation in the spindle checkpoint. We found that the dynamic mitotic phosphorylation of YAP was CDC14-dependent. We also showed that YAP was required for the spindle checkpoint activation induced by spindle poisons. Mitotic phosphorylation of YAP was required for activation of the spindle checkpoint. Furthermore, enhanced expression of active YAP hyperactivated the spindle checkpoint and induced mitotic defects in a mitotic phosphorylation-dependent manner. Mechanistically, we documented that mitotic phosphorylation of YAP controlled transcription of genes associated with the spindle checkpoint. YAP constitutively associated with BubR1 (BUB1-related protein kinase), and knockdown of BubR1 relieved YAP-driven hyperactivation of the spindle checkpoint. Finally, we demonstrated that YAP promoted epithelial cell invasion via both mitotic phosphorylation and BubR1-dependent mechanisms. Together, our results reveal a novel link between YAP and the spindle checkpoint and indicate a potential mechanism underlying the oncogenic function of YAP through dysregulation of the spindle checkpoint. PMID:25605730

Yang, Shuping; Zhang, Lin; Chen, Xingcheng; Chen, Yuanhong; Dong, Jixin

2015-03-01

309

Late Intervention with anti-BRAFV600E Therapy Induces Tumor Regression in an Orthotopic Mouse Model of Human Anaplastic Thyroid Cancer  

PubMed Central

Human anaplastic thyroid cancer (ATC) is a lethal disease with an advanced clinical presentation and median survival of 3 months. The BRAFV600E oncoprotein is a potent transforming factor that causes human thyroid cancer cell progression in vitro and in vivo; therefore, we sought to target this oncoprotein in a late intervention model of ATC in vivo. We used the human ATC cell line 8505c, which harbors the BRAFV600E and TP53R248G mutations. Immunocompromised mice were randomized to receive the selective anti-BRAFV600E inhibitor, PLX4720, or vehicle by oral gavage 28 d after tumor implantation, 1 wk before all animals typically die due to widespread metastatic lung disease and neck compressive symptoms in this model. Mice were euthanized weekly to evaluate tumor volume and metastases. Control mice showed progressive tumor growth and lung metastases by 35 d after tumor implantation. At that time, all control mice had large tumors, were cachectic, and were euthanized due to their tumor-related weight loss. PLX4720-treated mice, however, showed a significant decrease in tumor volume and lung metastases in addition to a reversal of tumor-related weight loss. Mouse survival was extended to 49 d in PLX4720-treated animals. PLX4720 treatment inhibited cell cycle progression from 28 d to 49 d in vivo. PLX4720 induces striking tumor regression and reversal of cachexia in an in vivo model of advanced thyroid cancer that harbors the BRAFV600E mutation. PMID:22202162

Nehs, Matthew A.; Nucera, Carmelo; Nagarkatti, Sushruta S.; Sadow, Peter M.; Morales-Garcia, Dieter; Hodin, Richard A.

2012-01-01

310

Interleukin-21 regulates expression of key Epstein-Barr virus oncoproteins, EBNA2 and LMP1, in infected human B cells  

SciTech Connect

Epstein-Barr virus (EBV) persists for the life of the host by accessing the long-lived memory B cell pool. It has been proposed that EBV uses different combinations of viral proteins, known as latency types, to drive infected B cells to make the transition from resting B cells to memory cells. This process is normally antigen-driven. A major unresolved question is what factors coordinate expression of EBV latency proteins. We have recently described novel type III latency EBV{sup +} B cell lines (OCI-BCLs) that were induced to differentiate into late plasmablasts/early plasma cells in culture with interleukin-21 (IL-21), mimicking normal B cell development. The objective of this study was to determine whether IL-21-mediated signals also regulate the expression of key EBV latent proteins during this window of development. Here we show that IL-21-reduced gene and protein expression of growth-transforming EBV nuclear antigen 2 (EBNA2) in OCI-BCLs. By contrast, the expression of CD40-like, latent membrane protein 1 (LMP1) strongly increased in these cells suggesting an EBNA2-independent mode of regulation. Same results were also observed in Burkitt's lymphoma line Jijoye and B95-8 transformed lymphoblastoid cell lines. The effect of IL-21 on EBNA2 and LMP1 expression was attenuated by a pharmacological JAK inhibitor indicating involvement of JAK/STAT signalling in this process. Our study also shows that IL-21 induced transcription of ebna1 from the viral Q promoter (Qp)

Konforte, Danijela [Division of Stem Cell and Developmental Biology, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, M5G 2M9 (Canada); Department of Immunology, University of Toronto, Toronto, M5S 1A8 (Canada)], E-mail: danijela.konforte@utoronto.ca; Simard, Nathalie; Paige, Christopher J. [Division of Stem Cell and Developmental Biology, Princess Margaret Hospital, Ontario Cancer Institute, University Health Network, Toronto, M5G 2M9 (Canada); Department of Immunology, University of Toronto, Toronto, M5S 1A8 (Canada)

2008-04-25

311

The multifunctional FUS, EWS and TAF15 proto-oncoproteins show cell type-specific expression patterns and involvement in cell spreading and stress response  

PubMed Central

Background FUS, EWS and TAF15 are structurally similar multifunctional proteins that were first discovered upon characterization of fusion oncogenes in human sarcomas and leukemias. The proteins belong to the FET (previously TET) family of RNA-binding proteins and are implicated in central cellular processes such as regulation of gene expression, maintenance of genomic integrity and mRNA/microRNA processing. In the present study, we investigated the expression and cellular localization of FET proteins in multiple human tissues and cell types. Results FUS, EWS and TAF15 were expressed in both distinct and overlapping patterns in human tissues. The three proteins showed almost ubiquitous nuclear expression and FUS and TAF15 were in addition present in the cytoplasm of most cell types. Cytoplasmic EWS was more rarely detected and seen mainly in secretory cell types. Furthermore, FET expression was downregulated in differentiating human embryonic stem cells, during induced differentiation of neuroblastoma cells and absent in terminally differentiated melanocytes and cardiac muscle cells. The FET proteins were targeted to stress granules induced by heat shock and oxidative stress and FUS required its RNA-binding domain for this translocation. Furthermore, FUS and TAF15 were detected in spreading initiation centers of adhering cells. Conclusion Our results point to cell-specific expression patterns and functions of the FET proteins rather than the housekeeping roles inferred from earlier studies. The localization of FET proteins to stress granules suggests activities in translational regulation during stress conditions. Roles in central processes such as stress response, translational control and adhesion may explain the FET proteins frequent involvement in human cancer. PMID:18620564

Andersson, Mattias K; Ståhlberg, Anders; Arvidsson, Yvonne; Olofsson, Anita; Semb, Henrik; Stenman, Göran; Nilsson, Ola; Åman, Pierre

2008-01-01

312

Intracellular localization of the tumor suppressor HtrA1/Prss11 and its association with HPV16 E6 and E7 proteins.  

PubMed

We have a long-standing interest in a nuclear protease which appears to be involved in carcinogenesis. We recently identified the protease as high temperature requirement factor A 1 (HtrA1), also known as Prss11, which is member of an oxidative stress-response family of proteases. HtrA1 has been classified as a secreted protease involved in TGFbeta signaling, but recent work has shown HtrA1 to be a tumor suppressor. Here we show that processed forms of HtrA1 are found intracellularly and intranuclearly, and the active intranuclear form of HtrA1 shows an approximately Mr 29,000. Further, expression of HPV E6/E7 proteins is associated with a post-transcriptional up-regulation of HtrA1 (most notably the nuclear form), and HtrA1 is found associated with both HPV E6 and E7 proteins. PMID:18452160

Clawson, Gary A; Bui, Vuong; Xin, Ping; Wang, Ning; Pan, Weihua

2008-09-01

313

The bmi-1 oncoprotein is differentially expressed in non-small cell lung cancer and correlates with INK4A-ARF locus expression  

PubMed Central

Genes of the polycomb group function by silencing homeotic selector genes that regulate embryogenesis. In mice, downregulation of one of the polycomb genes, bmi-1, leads to neurological alterations and severe proliferative defects in lymphoid cells, whilst bmi-1 overexpression, together with upregulation of myc-1, induces lymphoma. An oncogenic function has been further supported in primary fibroblast studies where bmi-1 overexpression induces immortalization due to repression of p16/p19ARF, and where together with H-ras, it readily transforms MEFs. It was the aim of this study to assess the expression of bmi-1 in resectable non-small cell lung cancer (NSCLC) in association with p16 and p14ARF (=human p19ARF). Tumours (48 resectable NSCLC (32 squamous, 9 adeno-, 2 large cell, 4 undifferentiated carcinomas and 1 carcinoid); stage I, 29, II, 7, III, 12; T1, 18, T2, 30; differentiation: G1 12, G2 19, G3 17) were studied by immunohistochemistry for protein expression and by comparative multiplex PCR for gene amplification analysis. In tumour-free, normal lung tissue from patients, weak – moderate bmi-1 staining was seen in some epithelial cells, lymphocytes, glandular cells and in fibroblasts, whereas blood, endothelial, chondrocytes, muscle cells and adipocytes did not exhibit any bmi-1 expression. In tumours, malignant cells were negative/weakly, moderately and strongly positive in 20, 22 and 6 cases, respectively. As assessed by multiplex PCR, bmi-1 gene amplification was not the reason for high-level bmi-1 expression. Tumours with moderate or strong bmi-1 expression were more likely to have low levels of p16 and p14ARF (P = 0.02). Similarly, tumours negative for both, p16 and p14ARF, exhibit moderate–strong bmi-1 staining. 58% of resectable NSCLC exhibit moderate–high levels of bmi-1 protein. The inverse correlation of bmi-1 and the INK4 locus proteins expression (p16/p14ARF) supports a possible role for bmi-1 misregulation in lung carcinogenesis. © 2001 Cancer Research Campaign www.bjcancer.com PMID:11355949

Vonlanthen, S; Heighway, J; Altermatt, H J; Gugger, M; Kappeler, A; Borner, M M; Lohuizen, M van; Betticher, D C

2001-01-01

314

Maintenance of Vascular Endothelial Cell-Specific Properties after Immortalization with an Amphotrophic Replication-Deficient Retrovirus Containing Human Papilloma Virus 16 E6\\/E7 DNA  

Microsoft Academic Search

Primary human vascular endothelial cells were immortalized by the integration of a single DNA copy of an amphotrophic, replication-deficient retrovirus containing the E6\\/E7 genes of human papilloma virus. To date, the resulting cell lines, designated EC-RF7 and EC-RF24, have been cultured for more than 1 year. The cell lines have retained a diploid karyotype, display no abnormalities, and are able

Ruud Fontijn; Caroline Hop; Herm-Jan Brinkman; Rosalyn Slater; Andries Westerveld; Jan A. van Mourik; Hans Pannekoek

1995-01-01

315

Multilineage Differentiation of Adult Human Bone Marrow Progenitor Cells Transduced with Human Papilloma Virus Type 16 E6\\/E7 Genes  

Microsoft Academic Search

We have established a new adult human bone marrow-derived cell line hMPC 32F, stably transduced with human papilloma virus type 16 E6\\/E7 genes, that displays mesenchymal multilineage differentiation ability in vitro. The hMPC 32F cells exhibited a population doubling time of 22 h and have been maintained in culture for about 20 passages. When cultured in conditions promoting osteogenic, adipogenic,

A. M. Osyczka; U. Nöth; J. O'Connor; E. J. Caterson; K. Yoon; K. G. Danielson; R. S. Tuan

2002-01-01

316

Sequence variation in the Early genes E1^E4, E6 and E7 of Human Papilloma Virus type 6  

Microsoft Academic Search

The majority of condylomata acuminata (anogenital warts) are caused by infection with Human Papilloma Virus type 6 (HPV-6). We have sequenced the HPV-6 early genes, E1^E4, E6 and E7 from wart biopsy DNA samples sourced from the UK and USA and derived a consensus sequence for these genes and the proteins they encode. When compared to the prototype HPV-6b sequence,

D Krige; H. R Mills; E. L Berrie; N. C Doherty; D. K Jones; C. A Ryan; H Davies; S Myint; D. J McCance; G. T Layton; T. J French

1997-01-01

317

T-cell response to human papillomavirus type 58 L1, E6, And E7 peptides in women with cleared infection, cervical intraepithelial neoplasia, or invasive cancer.  

PubMed

Human papillomavirus type 58 (HPV-58) exists in a relatively high prevalence in certain parts of the world, including East Asia. This study examined the T-cell response to HPV-58 L1, E6, and E7 peptides among women with cleared infection, cervical intraepithelial neoplasia grade 2 (CIN2) or CIN3, or invasive cervical cancer (ICC). Peptides found to be reactive in the in vitro peptide binding assay or mouse-stimulating study were tested with a gamma interferon (IFN-gamma) enzyme-linked immunospot (ELISPOT) assay to detect peptide-specific responses from the peripheral blood mononuclear cells (PBMC) collected from 91 HPV-58-infected women (32 with cleared infection, 16 CIN2, 15 CIN3, and 28 ICC). Four HLA-A11-restricted HPV-58 L1 peptides, located at amino acid positions 296 to 304, 327 to 335, 101 to 109, and 469 to 477, showed positive IFN-gamma ELISPOT results and were mainly from women with cleared infection. Two HLA-A11-restricted E6 peptides (amino acid positions 64 to 72 and 94 to 102) and three HLA-A11-restricted E7 peptides (amino acid positions 78 to 86, 74 to 82, and 88 to 96) showed a positive response. A response to E6 and E7 peptides was mainly observed from subjects with CIN2 or above. One HLA-A2-restricted E6 peptide, located at amino acid position 99 to 107, elicited a positive response in two CIN2 subjects. One HLA-A24-restricted L1 peptide, located at amino acid position 468 to 476, also elicited a positive response in two CIN2 subjects. In summary, this study has identified a few immunogenic epitopes for HPV-58 E6 and E7 proteins. It is worthwhile to further investigate whether responses to these epitopes have a role in clearing an established cervical lesion. PMID:20668141

Chan, Paul K S; Liu, Shih-Jen; Cheung, T H; Yeo, Winnie; Ngai, S M; Cheung, Jo L K; Chong, Pele; Man, Stephen

2010-09-01

318

UCL CENTRE FOR ADVANCED SPATIAL ANALYSIS Centre for Advanced Spatial Analysis University College London 1 -19 Torrington Place Gower St London WC1E 7HB  

E-print Network

London 1 - 19 Torrington Place Gower St London WC1E 7HB Tel: +44 (0)20 7679 1782 casa@ucl.ac.uk www.casa.ucl.ac.uk WORKING PAPERS SERIES Collaborative Mapping of London Using Google Maps: The LondonProfiler ISSN 1467-1298 Paper 132 - Mar 08 #12;Collaborative Mapping of London Using Google Maps: The LondonProfiler Maurizio

Jones, Peter JS

319

The E2F5 repressor is an activator of E6/E7 transcription and of the S-phase entry in HPV18-associated cells.  

PubMed

High-risk papillomavirus type 18 (HPV18) is one of the less represented HPV types in low-grade lesions of the anogenital tract, whereas it occupies the second place in cervical cancer, where it can be found in 16% of the cases worldwide, after HPV16 present in 54% of them. These epidemiological data indicate that HPV18 infection is more prone to carcinogenic progression. The main oncogenic proteins, E6 and E7 of HPV18, are functionally comparable to the homologous proteins of the other high-risk viruses, including HPV16. In this work, we investigated the possibility that the higher oncogenic potential of HPV18 might be due to transcriptional regulation of the E6/E7 oncogenes. By comparing the E6/E7 promoter and enhancer sequences of the mucosal HPV genomes, we identified E2F binding sites specific for HPV18. The E2F family of transcription factors contains activators (E2F1-3) and repressors (E2F4-8) that regulate the transcription of S-phase and mitotic genes and thereby have a crucial role in cell-cycle progression. Surprisingly, we identified E2F5 as a direct activator of HPV18 E6/E7 transcription by sequential silencing of E2F members in HeLa cells. In addition, we could show that E2F5 positively regulates S-phase entry in HeLa cells and that this activation of the cell cycle by a member of the E2F repressor family is specific for HPV18-expressing cells. Diverting the function of E2F5 from a cell-cycle repressor into an activator might contribute to the higher oncogenic potential of HPV18 when compared with other high-risk HPV types. PMID:20639900

Teissier, S; Pang, C L; Thierry, F

2010-09-01

320

The 11 and E7 Integrins Define a Subset of Dendritic Cells in Peripheral Lymph Nodes with Unique Adhesive and Antigen Uptake Properties1  

Microsoft Academic Search

Dendritic cells (DCs) are a heterogeneous population of APCs with critical roles in T cell activation and immune regulation. We report in this study the identification and characterization of a novel subset of DCs resident in skin-draining peripheral lymph nodes of normal mice. This subset of CD11chighCD40highCD8intermediate (int) DCs expresses the collagen-binding integrin, 11, and the E-cadherin-binding integrin, E7. Although

Jonathan T. Pribila; Andrea A. Itano; Kristen L. Mueller; Yoji Shimizu

321

Behavioral and electrophysiological activity of ( Z,E )-7,9,11-dodecatrienyl formate, a mimic of the major sex pheromone component of carob moth, Ectomyelois ceratoniae  

Microsoft Academic Search

The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing

J. L. Todd; J. G. Millar; R. S. Vetter; T. C. Baker

1992-01-01

322

Leukemic transformation by the v-ErbA oncoprotein entails constitutive binding to and repression of an erythroid enhancer in vivo.  

PubMed Central

v-ErbA, a mutated thyroid hormone receptor alpha (TRalpha), is thought to contribute to avian erythroblastosis virus (AEV)-induced leukemic transformation by constitutively repressing transcription of target genes. However, the binding of v-ErbA or any unliganded nuclear receptor to a chromatin-embedded response element as well as the role of the N-CoR-SMRT-HDAC co-repressor complex in mediating repression remain hypothetical. Here we identify a v-ErbA-response element, VRE, in an intronic DNase I hypersensitive site (HS2) of the chicken erythroid carbonic anhydrase II (CAII) gene. In vivo footprinting shows that v-ErbA is constitutively bound to this HS2-VRE in transformed, undifferentiated erythroblasts along with other transcription factors like GATA-1. Transfection assays show that the repressed HS2 region can be turned into a potent enhancer in v-ErbA-expressing cells by mutation of the VRE. Differentiation of transformed cells alleviates v-ErbA binding concomitant with activation of CAII transcription. Co-expression of a gag-TRalpha fusion protein in AEV-transformed cells and addition of ligand derepresses CAII transcription. Treatment of transformed cells with the histone deacetylase inhibitor, trichostatin A, derepresses the endogenous, chromatin-embedded CAII gene, while a transfected HS2-enhancer construct remains repressed. Taken together, our data suggest that v-ErbA prevents CAII activation by 'neutralizing' in cis the activity of erythroid transcription factors. PMID:9857194

Ciana, P; Braliou, G G; Demay, F G; von Lindern, M; Barettino, D; Beug, H; Stunnenberg, H G

1998-01-01

323

Acetylation of the human T-cell leukemia virus type 1 Tax oncoprotein by p300 promotes activation of the NF-{kappa}B pathway  

SciTech Connect

The oncogenic potential of the HTLV-1 Tax protein involves activation of the NF-{kappa}B pathway, which depends on Tax phosphorylation, ubiquitination and sumoylation. We demonstrate that the nuclei of Tax-expressing cells, including HTLV-1 transformed T-lymphocytes, contain a pool of Tax molecules acetylated on lysine residue at amino acid position 346 by the transcriptional coactivator p300. Phosphorylation of Tax on serine residues 300/301 was a prerequisite for Tax localization in the nucleus and correlated with its subsequent acetylation by p300, whereas sumoylation, resulting in the formation of Tax nuclear bodies in which p300 was recruited, favored Tax acetylation. Overexpression of p300 markedly increased Tax acetylation and the ability of a wild type HTLV-1 provirus, -but not of a mutant provirus carrying an acetylation deficient Tax gene-, to activate gene expression from an integrated NF-{kappa}B-controlled promoter. Thus, Tax acetylation favors NF-{kappa}B activation and might play an important role in HTLV-1-induced cell transformation.

Lodewick, Julie; Lamsoul, Isabelle; Polania, Angela; Lebrun, Sylvie [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium); Burny, Arsene [Faculte des Sciences Agronomiques de Gembloux, Gembloux (Belgium); Ratner, Lee [Division of Molecular Oncology, Washington University School of Medicine, St Louis (United States); Bex, Francoise [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium)], E-mail: fbex@ulb.ac.be

2009-03-30

324

An actin-binding function contributes to transformation by the Bcr-Abl oncoprotein of Philadelphia chromosome-positive human leukemias.  

PubMed Central

In Philadelphia chromosome-positive human leukemias, which include chronic myelogenous leukemia and some acute lymphocytic leukemias, the c-abl proto-oncogene on chromosome 9 becomes fused to the bcr gene on chromosome 22, and Bcr-Abl fusion proteins are produced. The Bcr sequences activate the Abl tyrosine kinase which is required for the transforming function of Bcr-Abl. The Bcr sequences also enhance an F-actin-binding activity associated with c-Abl. Here, we show that binding of c-Abl and Bcr-Abl proteins to actin filaments in vivo and in vitro is mediated by an evolutionarily conserved domain at the C-terminal end of c-Abl. The c-Abl F-actin-binding domain contains a consensus motif found in several other actin-crosslinking proteins. Mutations in the consensus motif are shown to abolish binding to F-actin. Bcr-Abl proteins unable to associate with F-actin have a reduced ability to transform Rat-1 fibroblasts and to abrogate the requirement for interleukin-3 in the lymphoblastoid cell line Ba/F3. In transformed cells, Bcr-Abl induces a redistribution of F-actin into punctate, juxtanuclear aggregates. The binding to actin filaments has important implications for the pathogenic and physiological functions of the Bcr-Abl and c-Abl proteins. Images PMID:8467803

McWhirter, J R; Wang, J Y

1993-01-01

325

SMCX and components of the TIP60 complex contribute to E2 regulation of the HPV E6/E7 promoter.  

PubMed

An important step in the malignant progression of HPV-associated lesions is the dysregulation of expression of the viral E6 and E7 oncogenes. This is often achieved through the loss of expression of E2, which represses the HPV LCR promoter and E6/E7 expression. Our previous studies confirmed a role for Brd4 in mediating the E2 transcriptional repression function, and identified JARID1C/SMCX and EP400 as contributors to E2-mediated repression. Here we show that TIP60, a component of the TIP60/TRRAP histone acetyltransferase complex, also contributes to the E2 repression function, and we extend our studies on SMCX. Di- and tri-methyl marks on histone H3K4 are reduced in the presence of E2 and SMCX, suggesting a mechanism by which SMCX contributes to E2-mediated repression of the HPV LCR. Together, these findings lead us to hypothesize that E2 recruits histone-modifying cellular proteins to the HPV LCR, resulting in transcriptional repression of E6 and E7. PMID:25222147

Smith, Jennifer A; Haberstroh, Friederike S; White, Elizabeth A; Livingston, David M; DeCaprio, James A; Howley, Peter M

2014-11-01

326

Cervical carcinoma cells transfected with the CD80 gene elicit a primary cytotoxic T lymphocyte response specific for HPV 16 E7 antigens.  

PubMed

Cervical carcinoma is strongly associated with human papillomavirus (HPV) type 16, and the transforming viral genes E6 and F7 are steadily expressed by the tumor cells. Therefore these viral oncogenes may be regarded as tumor-associated antigens. Our previous studies showed that cervical cancer cells after introduction of the CD80 gene activated allogeneic cytotoxic T lymphocytes (CTLs). In this study, we tested whether HPV 16+ cervical tumor cells (CaSki) expressing CD80 were able to activate CTLs recognizing HPV 16 E7 antigen. To this end, CD80+ CaSki cells (HLA-A*0201+) were used to stimulate peripheral blood T lymphocytes from HLA-A*0201+ healthy donors. We found that the activated T cells were able to lyse parental CaSki cells as well as Epstein-Barr virus-immortalized autologous B cells loaded with HLA-A*0201-restricted E7 peptides (amino acids 11-19, 82-90, 86-93). In contrast, no lysis was observed against target cells loaded with a control HIV-reverse transcriptase peptide (amino acid 476-484, HLA-A 0201-restricted). Our data, for the first time, provide evidence that CD80-expressing cervical cancer cells are able to activate tumor-specific CTLs using HPV 16 E7 as tumor-associated antigens. PMID:9408608

Kaufmann, A M; Gissmann, L; Schreckenberger, C; Qiao, L

1997-01-01

327

The adenovirus E1A oncoprotein N-terminal transcriptional repression domain enhances p300 autoacetylation and inhibits histone H3 Lys18 acetylation  

PubMed Central

Expression of the adenovirus E1A N-terminal transcription repression domain alone (E1A 1-80) represses transcription from specific promoters such as HER2 [1] and from reconstituted chromatin [2]. Significantly, E1A 1-80 can induce the death of human breast cancer cells over-expressing the HER2 oncogene [1] as well as other cancer cells. Here, we report that E1A 1-80 alone is sufficient to inhibit H3K18 acetylation in vivo and p300-mediated H3K18 acetylation in reconstituted chromatin. Of interest, hypoacetylation of H3K18 has been correlated with the survival of tumor cells and the poor prognosis of many cancers [3, 4]. E1A 1-80 enhances p300 autoacetylation and concurrently inhibits H3K18 acetylation in chromatin in a dose-dependent manner. Pre-acetylation of p300 by incubation with acetyl-CoA alone reduces p300's ability to acetylate H3K18 in chromatin. Additional acetylation of p300 in the presence of E1A 1-80 produces stronger inhibition of H3K18 acetylation. These findings indicate that autoacetylation of p300 greatly reduces its ability to acetylate H3K18. The results reported here combined with our previous findings suggest that E1A can repress transcription by multiple strategies, including altering the chromatin modifying activity of p300 and dissociating TFIID from the TATA box thus disrupting formation of the transcription pre-initiation complex [5, 6

Zhao, Ling-Jun; Loewenstein, Paul M.; Green, Maurice

2015-01-01

328

Variations of human papillomavirus type 58 E6, E7, L1 genes and long control region in strains from women with cervical lesions in Liaoning province, China.  

PubMed

Infection with certain types of human papillomaviruses (HPVs) is a risk factor for the development of cervical cancer. HPV type 58 (HPV 58) is prevalent among Chinese women. The intratype sequence variants differ in oncogenic potential and their prevalences vary across geographic regions. The objective of this study was to analyze the variations of HPV 58 E6, E7, L1 genes and long control region (LCR) in a large samples collected from northeastern Chinese women with cervical lesions. A total of 2938 cervical samples were collected and tested for HPV type using a chip hybridization assay. The E6, E7, L1 genes and LCR of HPV 58 strains were amplified and the amplicons were subjected to direct nucleotide sequencing for variation identification. A total of 235 specimens were HPV 58 positive. High proportions of HPV 58 E6 (83.8%), E7 (76.7%), L1 (90.8%) genes and LCR (91.4%) variants were identified in strains from Chinese women. The most frequently observed variations were C307T (52.4%) in E6, T744G (74.9%) in E7, A6014C (56.9%) in L1 genes and C7266T, A7714G (55.2%) in LCR. For the E6 gene, nine nucleotide variations were identified. Among them, the A140G (T11A), A184C (E25D), G266C (V53L) and A313G were novel variations. Sequencing of the E7 gene revealed four typical nucleotide changes: G761A (G63D), G694A (G41R), T803C (V77A) and T744G. In the L1 gene, 39 nucleotide variations and 13 amino acid substitutions were identified. Among these mutations, 21 variations are reported here for the first time. Lineage A of HPV 58 was found in 142 of 174 strains (81.6%). The most prevalent HPV 58 variants in Chinese northeastern women belongs to lineage A. Novel variations in E6 and L1 genes were also reported. These findings provide new data regarding E6 and L1 gene variations of HPV 58 from women in northeast China. PMID:22659102

Liu, Jian-hua; Lu, Zhi-tao; Wang, Gui-li; Zhou, Wei-qiang; Liu, Chao; Yang, Lian-xia; Sun, Zheng-rong; Ruan, Qiang

2012-10-01

329

Negative Charge at the Casein Kinase II Phosphorylation Site is Important for Transformation but not for Rb Protein Binding by the E7 Protein of Human Papillomavirus Type 16  

Microsoft Academic Search

The human papillomavirus E7 protein is phosphorylated at the two serines in positions 31\\/32, which are part of a consensus sequence for casein kinase II (CKII). In this study, we have investigated the effect of CKII phosphorylation site mutations, all of which lead to unphosphorylated E7 proteins. The replacement of the two serines by uncharged alanine residues drastically reduced the

Juliane M. Firzlaff; Bernhard Luscher; Robert N. Eisenman

1991-01-01

330

Bcl-3, induced by Tax and HTLV-1, inhibits NF-?B activation and promotes autophagy.  

PubMed

The human T cell leukemia virus type 1 (HTLV-1) is a complex human retrovirus that causes an aggressive leukemia known as adult T cell leukemia (ATL). The HTLV-1-encoded oncoprotein Tax induces persistent activation of the nuclear factor-?B (NF-?B) pathway, which is perceived as the primary cause of ATL. Bcl-3, a member of the NF-?B inhibitor (I?B) family, is highly expressed in many HTLV-1-infected T cell lines and ATL cells. However, the role of Bcl-3 in Tax-induced NF-?B activation has not been fully elucidated. Here, we show that Tax induces Bcl-3 expression, which in turn negatively regulates the Tax-induced NF-?B activation. Interestingly, both Bcl-3 up-regulation and NF-?B inhibition promote the autophagy process in HTLV-1-infected cells. Consistent with this, over-expression of Bcl-3 also results in enhancement of rapamycin-, pifithrin-?- or starvation-induced autophagy in control cells. Together, these data demonstrate that Bcl-3 acts as a negative regulator of NF-?B activation and promotes autophagy in HTLV-1-infected cells. PMID:24044922

Wang, Jinheng; Niu, Zhiguo; Shi, Ying; Gao, Cai; Wang, Xia; Han, Jingxian; Li, Junying; Gao, Zhitao; Zhu, Xiaofei; Song, Xiangfeng; Qin, Zhihai; Wang, Hui

2013-12-01

331

PEBP2/CBF, the murine homolog of the human myeloid AML1 and PEBP2 beta/CBF beta proto-oncoproteins, regulates the murine myeloperoxidase and neutrophil elastase genes in immature myeloid cells.  

PubMed Central

The myeloperoxidase (MPO) and neutrophil elastase genes are expressed specifically in immature myeloid cells. The integrity of a polyomavirus enhancer core sequence, 5'-AACCACA-3', is critical to the activity of the murine MPO proximal enhancer. This element binds two species, myeloid nuclear factors 1 alpha and 1 beta (MyNF1 alpha and -beta), present in 32D cl3 myeloid cell nuclear extracts. The levels of the MyNF1s increase during early 32D cl3 cell granulocytic differentiation. Both MyNF1 alpha and -beta supershift with an antiserum raised by using a peptide derived from the N terminus of polyomavirus enhancer-binding protein 2/core-binding factor (PEBP2/CBF) alpha subunit. The specific peptide inhibits these supershifts. In vitro-translated PEBP2/CBF DNA-binding domain binds the murine MPO PEBP2/CBF site. An alternate PEBP2/CBF consensus site, 5'-GACCGCA-3', but not a simian virus 40 enhancer core sequence, 5'-TTCCACA-3', binds the MyNF1s in vitro and activates a minimal murine MPO-thymidine kinase promoter in vivo. The murine neutrophil elastase gene 100-bp 5'-flanking sequences contain several functional elements, including potential binding sites for PU.1, C/EBP, c-Myb, and PEBP2/CBF. The functional element 5'-GGCCACA-3' located at positions -66 to 72 differs from the PEBP2/CBF consensus (5'-PuACCPuCA-3') only by an A-to-G transition at position 2. This DNA element binds MyNF1 alpha and -beta weakly. The N terminis of two PEBP2/CBF alpha subunit family members, PEBP2 alpha A and PEBP2 alpha B (murine AML1), are nearly identical, and 32D c13 cl3 cells contain both corresponding mRNAs. Since t(8;21), t(3;21), and inv(16), associated with myeloid leukemias, disrupt subunits of PEBP2/CBF, we speculate that the resulting oncoproteins, AML1-ETO, AML1-EAP, AML1-Evi1, and CBF beta-MYH11, inhibit early myeloid differentiation. Images PMID:8035830

Nuchprayoon, I; Meyers, S; Scott, L M; Suzow, J; Hiebert, S; Friedman, A D

1994-01-01

332

Effect of ferric ions on reactive oxygen species formation, cervical cancer cell lines growth and E6/E7 oncogene expression.  

PubMed

As iron ions may participate in the pathogenesis of cancer and viral infections, the aim of this study was to monitor their influence on proliferation, E6 and E7 oncogene expression and reactive oxygen species (ROS) production in two human papilloma virus (HPV) positive cervical carcinoma cell lines (HeLa and SiHa) and one HPV negative vulvar cell line (A431). The anti-anaemic drug, ferric-sorbitol-citric acid complex (FSC) as a source of Fe(III) ions was used. Cells were treated with FSC at the concentrations between 0.001 and 1 mM Fe(III) for different time periods. Fe(III) ions inhibited the viability of HeLa and A431 cells while it had no influence on SiHa cells. Furthermore, Fe(III) treatment showed a time-dependent and a higher stimulatory effect on E6/E7 expression in SiHa cells than in HeLa cells. Fe(III) ion treatment with concentrations lower than 0.1mM showed a time and a concentration dependent intracellular ROS production in all tested cell lines, while the treatment with 1mM concentration decreased ROS production in all tested cell lines. In conclusion, Fe(III) ion treatment apart from having an anti-tumour effect, as we previously described, enhances survival of HPV 16-positive cells and might be associated with HPV oncogenesis. PMID:21044880

Poljak-Blazi, Marija; Jaganjac, Morana; Sabol, Ivan; Mihaljevic, Branka; Matovina, Mihaela; Grce, Magdalena

2011-02-01

333

Intercellular trafficking of the nuclear oncoprotein DEK  

E-print Network

DEK is a biochemically distinct, conserved nonhistone protein that is vital to global heterochromatin integrity. In addition, DEK can be secreted and function as a chemotactic, proinflammatory factor. Here we show that ...

Ploegh, Hidde

334

Targeting MUC1-C is synergistic with bortezomib in downregulating TIGAR and inducing ROS-mediated myeloma cell death.  

PubMed

The proteosome inhibitor bortezomib (BTZ) induces endoplasmic reticulum and oxidative stress in multiple myeloma (MM) cells. The mucin 1 C-terminal subunit (MUC1-C) oncoprotein is aberrantly expressed in most MM cells, and targeting MUC1-C with GO-203, a cell-penetrating peptide inhibitor of MUC1-C homodimerization, is effective in inducing reactive oxygen species (ROS)-mediated MM cell death. The present results demonstrate that GO-203 and BTZ synergistically downregulate expression of the p53-inducible regulator of glycolysis and apoptosis (TIGAR), which promotes shunting of glucose-6-phosphate into the pentose phosphate pathway to generate reduced glutathione (GSH). In turn, GO-203 blocks BTZ-induced increases in GSH and results in synergistic increases in ROS and MM cell death. The results also demonstrate that GO-203 is effective against BTZ-resistant MM cells. We show that BTZ resistance is associated with BTZ-induced increases in TIGAR and GSH levels, and that GO-203 resensitizes BTZ-resistant cells to BTZ treatment by synergistically downregulating TIGAR and GSH. The GO-203/BTZ combination is thus highly effective in killing BTZ-resistant MM cells. These findings support a model in which targeting MUC1-C is synergistic with BTZ in suppressing TIGAR-mediated regulation of ROS levels and provide an experimental rationale for combining GO-203 with BTZ in certain settings of BTZ resistance. PMID:24632713

Yin, Li; Kufe, Turner; Avigan, David; Kufe, Donald

2014-05-01

335

Ligand binding to heme proteins: III. FTIR studies of His-E7 and Val-E11 mutants of carbonmonoxymyoglobin.  

PubMed Central

Fouier-transform infrared (FTIR) difference spectra of several His-E7 and Val-E11 mutants of sperm whale carbonmonoxymyoglobin were obtained by photodissociation at cryogenic temperatures. The IR absorption of the CO ligand shows characteristic features for each of the mutants, both in the ligand-bound (A) state and in the photodissociated (B) state. For most of the mutants, a single A substate band is observed, which points to the crucial role of the His-E7 residue in determining the A substrate spectrum of the bound CO in the native structure. The fact that some of the mutants show more than one stretch band of the bound CO indicates that the appearance of multiple A substates is not exclusively connected to the presence of His-E7. In all but one mutant, multiple stretch bands of the CO in the photodissociated state are observed; these B substates are thought to arise from discrete positions and/or orientations of the photodissociated ligand in the heme pocket. The red shifts of the B bands with respect to the free-gas frequency indicate weak binding in the heme pocket. The observation of similar red shifts in microperoxidase (MP-8), where there is no residue on the distal side, suggests that the photodissociated ligand is still associated with the heme iron. Photoselection experiments were performed to determine the orientation of the bound ligand with respect to the heme normal by photolyzing small fractions of the sample with linearly polarized light at 540 nm. The resulting linear dichroism in the CO stretch spectrum yielded angles alpha > 20 degrees between the CO molecular axis and the heme normal for all of the mutants. We conclude that the off-axis position of the CO ligand in the native structure does not arise from steric constraints imposed by the distal histidine. There is no clear correlation between the size of the distal residue and the alpha of the CO ligand. PMID:8312483

Braunstein, D. P.; Chu, K.; Egeberg, K. D.; Frauenfelder, H.; Mourant, J. R.; Nienhaus, G. U.; Ormos, P.; Sligar, S. G.; Springer, B. A.; Young, R. D.

1993-01-01

336

Metformin induces differentiation in acute promyelocytic leukemia by activating the MEK/ERK signaling pathway  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Metformin induces differentiation in NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces activation of the MEK/ERK signaling pathway in APL cells. Black-Right-Pointing-Pointer Metformin synergizes with ATRA to trigger maturation of NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces the relocalization and degradation of the PML-RAR{alpha} fusion protein. Black-Right-Pointing-Pointer The study may be applicable for new differentiation therapy in cancer treatment. -- Abstract: Recent studies have shown that metformin, a widely used antidiabetic agent, may reduce the risk of cancer development. In this study, we investigated the antitumoral effect of metformin on both acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) cells. Metformin induced apoptosis with partial differentiation in an APL cell line, NB4, but only displayed a proapoptotic effect on several non-M3 AML cell lines. Further analysis revealed that a strong synergistic effect existed between metformin and all-trans retinoic acid (ATRA) during APL cell maturation and that metformin induced the hyperphosphorylation of extracellular signal-regulated kinase (ERK) in APL cells. U0126, a specific MEK/ERK activation inhibitor, abrogated metformin-induced differentiation. Finally, we found that metformin induced the degradation of the oncoproteins PML-RAR{alpha} and c-Myc and activated caspase-3. In conclusion, these results suggest that metformin treatment may contribute to the enhancement of ATRA-induced differentiation in APL, which may deepen the understanding of APL maturation and thus provide insight for new therapy strategies.

Huai, Lei; Wang, Cuicui; Zhang, Cuiping; Li, Qihui; Chen, Yirui; Jia, Yujiao; Li, Yan; Xing, Haiyan; Tian, Zheng; Rao, Qing; Wang, Min [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China); Wang, Jianxiang, E-mail: wangjx@ihcams.ac.cn [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)

2012-06-08

337

Re: Account 2155-E7P10 -Deepwater Oil Spill sand-berm report Jack L Kindinger 0 Rebecca J Deckard 05/26/201006:08 PM  

E-print Network

Re: Account 2155-E7P10 - Deepwater Oil Spill sand-berm report t Jack L Kindinger 0 Rebecca J-204-8998 Jack Kindinger USGS, St. Petersburg, FL On May 26, 2010, at 3:34 PM, Rebecca J Deckard > ······················································· > Rebecca J. Deckard, PSC Chief > USGS EPN, Raleigh PSC > (AL, GA., MS, NC, SC, TN, VA) > > U.S. Geological

Torgersen, Christian

338

SH4-domain-induced plasma membrane dynamization promotes bleb-associated cell motility.  

PubMed

SH4 domains provide bipartite membrane-targeting signals for oncogenic Src family kinases. Here we report the induction of non-apoptotic plasma membrane (PM) blebbing as a novel and conserved activity of SH4 domains derived from the prototypic Src kinases Src, Fyn, Yes and Lck as well as the HASPB protein of Leishmania parasites. SH4-domain-induced blebbing is highly dynamic, with bleb formation and collapse displaying distinct kinetics. These reorganizations of the PM are controlled by Rho but not Rac or Cdc42 GTPase signalling pathways. SH4-induced membrane blebbing requires the membrane association of the SH4 domain, is regulated by the activities of Rock kinase and myosin II ATPase, and depends on the integrity of F-actin as well as microtubules. Endogenous Src kinase activity is crucial for PM blebbing in SH4-domain-expressing cells, active Src and Rock kinases are enriched in SH4-domain-induced PM blebs, and PM blebbing correlates with enhanced cell invasion in 3D matrices. These results establish a novel link between SH4 domains, Src activity and Rho signalling, and implicate SH4-domain-mediated PM dynamization as a mechanism that influences invasiveness of cells transformed by SH4-domain-containing oncoproteins. PMID:17959630

Tournaviti, Stella; Hannemann, Sebastian; Terjung, Stefan; Kitzing, Thomas M; Stegmayer, Carolin; Ritzerfeld, Julia; Walther, Paul; Grosse, Robert; Nickel, Walter; Fackler, Oliver T

2007-11-01

339

Alteration of the lipid profile in lymphomas induced by MYC overexpression  

PubMed Central

Overexpression of the v-myc avian myelocytomatosis viral oncogene homolog (MYC) oncogene is one of the most commonly implicated causes of human tumorigenesis. MYC is known to regulate many aspects of cellular biology including glucose and glutamine metabolism. Little is known about the relationship between MYC and the appearance and disappearance of specific lipid species. We use desorption electrospray ionization mass spectrometry imaging (DESI-MSI), statistical analysis, and conditional transgenic animal models and cell samples to investigate changes in lipid profiles in MYC-induced lymphoma. We have detected a lipid signature distinct from that observed in normal tissue and in rat sarcoma-induced lymphoma cells. We found 104 distinct molecular ions that have an altered abundance in MYC lymphoma compared with normal control tissue by statistical analysis with a false discovery rate of less than 5%. Of these, 86 molecular ions were specifically identified as complex phospholipids. To evaluate whether the lipid signature could also be observed in human tissue, we examined 15 human lymphoma samples with varying expression levels of MYC oncoprotein. Distinct lipid profiles in lymphomas with high and low MYC expression were observed, including many of the lipid species identified as significant for MYC-induced animal lymphoma tissue. Our results suggest a relationship between the appearance of specific lipid species and the overexpression of MYC in lymphomas. PMID:24994904

Eberlin, Livia S.; Gabay, Meital; Fan, Alice C.; Gouw, Arvin M.; Tibshirani, Robert J.; Felsher, Dean W.; Zare, Richard N.

2014-01-01

340

In vivo processing of DNase colicins E2 and E7 is required for their import into the cytoplasm of target cells.  

PubMed

DNase colicins E2 and E7, both of which appropriate the BtuB/Tol translocation machinery to cross the outer membrane, undergo a processing step as they enter the cytoplasm. This endoproteolytic cleavage is essential for their killing action. A processed form of the same size, 18.5 kDa, which corresponds to the C-terminal catalytic domain, was detected in the cytoplasm of bacteria treated with either of the two DNase colicins. The inner-membrane protease FtsH is necessary for the processing that allows the translocation of the colicin DNase domain into the cytoplasm. The processing occurs near residue D420, at the same position as the FtsH-dependent cleavage in RNase colicins E3 and D. The cleavage site is located 30 amino acids upstream of the DNase domain. In contrast, the previously reported periplasm-dependent colicin cleavage, located at R452 in colicin E2, was shown to be generated by the outer-membrane protease OmpT and we show that this cleavage is not physiologically relevant for colicin import. Residue R452, whose mutated derivatives led to toxicity defect, was shown to have no role in colicin processing and translocation, but it plays a key role in the catalytic activity, as previously reported for other DNase colicins. Membrane associated forms of colicins E2 and E7 were detected on target cells as proteinase K resistant peptides, which include both the receptor-binding and DNase domains. A similar, but much less proteinase K-resistant form was also detected with RNase colicin E3. These colicin forms are not relevant for colicin import, but their detection on the cell surface indicates that whole nuclease-colicin molecules are found in a stable association with the outer-membrane receptor BtuB of the target cells. PMID:24840776

Mora, Liliana; de Zamaroczy, Miklos

2014-01-01

341

The detection of circulating tumor cells expressing E6/E7 HR-HPV oncogenes in peripheral blood in cervical cancer patients after radical hysterectomy.  

PubMed

The aim of this study was to establish the sensitive, specific and clinically acceptable method for detection of tumor cells (TCs) circulating in peripheral blood (PB) of cervical cancer patients without the clinically detectable risk of disease progression. The 7.5 ml of PB of healthy donor was spiked with 5 to 100 cells from SiHa or HeLa cell lines. The spiked tumor cells were collected without gradient centrifugation, by standard gradient centrifugation or by modified gradient centrifugation combined with immunomagnetic separation using EpCAM antibody with affinity for epithelial cell adhesion molecule. The number of collected TCs was determined by EpCAM-FITC-staining and their viability was detected by nested RT-PCR amplifying E6/E7 HR-HPV 16 or HR-HPV 18 oncogenes. For the technical validation of this approach the TCs separation and RT-PCRs were repeated several times. The recovery of viable TCs was reproducibly higher using modified gradient centrifugation combined with immunomagnetic separation in comparison with standard approach. The recovery of TCs in low number of spiked TCs (range from 5 - 20 TCs in 7.5 ml of PB) using modified gradient centrifugation was not reproducible. The recovery of TCs in higher number of spiked TCs (25 TCs and more in 7.5 ml of PB) was reproducible with average recovery about 50 %. The sensitivity of nested RT-PCR amplifying E6/E7 oncogenes was decisively influenced by the number of recovered TCs and the amount of cDNA introduced to RT-PCR, as well. Using this approach we were allowed to detect circulating TCs (CTCs) in cervical cancer patients without metastases, thus this procedure might become a tool to early estimation of disease progression. According to our knowledge, this is the first report describing the use of EpCAM antibody for CTCs detection in cervical cancer patients. PMID:19309226

Weismann, P; Weismanova, E; Masak, L; Mlada, K; Keder, D; Ferancikova, Z; Vizvaryova, M; Konecny, M; Zavodna, K; Kausitz, J; Benuska, J; Repiska, V

2009-01-01

342

In Vivo Processing of DNase Colicins E2 and E7 Is Required for Their Import into the Cytoplasm of Target Cells  

PubMed Central

DNase colicins E2 and E7, both of which appropriate the BtuB/Tol translocation machinery to cross the outer membrane, undergo a processing step as they enter the cytoplasm. This endoproteolytic cleavage is essential for their killing action. A processed form of the same size, 18.5 kDa, which corresponds to the C-terminal catalytic domain, was detected in the cytoplasm of bacteria treated with either of the two DNase colicins. The inner-membrane protease FtsH is necessary for the processing that allows the translocation of the colicin DNase domain into the cytoplasm. The processing occurs near residue D420, at the same position as the FtsH-dependent cleavage in RNase colicins E3 and D. The cleavage site is located 30 amino acids upstream of the DNase domain. In contrast, the previously reported periplasm-dependent colicin cleavage, located at R452 in colicin E2, was shown to be generated by the outer-membrane protease OmpT and we show that this cleavage is not physiologically relevant for colicin import. Residue R452, whose mutated derivatives led to toxicity defect, was shown to have no role in colicin processing and translocation, but it plays a key role in the catalytic activity, as previously reported for other DNase colicins. Membrane associated forms of colicins E2 and E7 were detected on target cells as proteinase K resistant peptides, which include both the receptor-binding and DNase domains. A similar, but much less proteinase K-resistant form was also detected with RNase colicin E3. These colicin forms are not relevant for colicin import, but their detection on the cell surface indicates that whole nuclease-colicin molecules are found in a stable association with the outer-membrane receptor BtuB of the target cells. PMID:24840776

Mora, Liliana; de Zamaroczy, Miklos

2014-01-01

343

MINI REVIEW MECHANISMS OF GENOMIC INSTABILITY IN HUMAN CANCER: INSIGHTS  

E-print Network

PAPILLOMAVIRUS ONCOPROTEINS Stefan DUENSING 1 * and Karl M¨UNGER 2 * 1 Molecular Virology Program, University-risk human papillomavirus (HPV)-associated anogenital neoplasia. The two HPV-encoded oncoproteins, E6 and E7 carcinogenesis. © 2003 Wiley-Liss, Inc. Human papillomaviruses (HPVs) are small DNA tumor viruses that cause

Dever, Jennifer A.

344

IER3 is a crucial mediator of TAp73?-induced apoptosis in cervical cancer and confers etoposide sensitivity  

PubMed Central

Infection with high-risk human papillomaviruses (HPVs) causes cervical cancer. E6 oncoprotein, an HPV gene product, inactivates the major gatekeeper p53. In contrast, its isoform, TAp73?, has become increasingly important, as it is resistant to E6. However, the intracellular signaling mechanisms that account for TAp73? tumor suppressor activity in cervix are poorly understood. Here, we identified that IER3 is a novel target gene of TAp73?. In particular, TAp73? exclusively transactivated IER3 in cervical cancer cells, whereas p53 and TAp63 failed to do. IER3 efficiently induced apoptosis, and its knockdown promoted survival of HeLa cells. In addition, TAp73?-induced cell death, but not p53-induced cell death, was inhibited upon IER3 silencing. Moreover, etoposide, a DNA-damaging chemotherapeutics, upregulated TAp73? and IER3 in a c-Abl tyrosine kinase-dependent manner, and the etoposide chemosensitivity of HeLa cells was largely determined by TAp73?-induced IER3. Of interest, cervical carcinomas from patients express no observable levels of two proteins. Thus, our findings suggest that IER3 is a putative tumor suppressor in the cervix, and the c-Ab1/p73?/IER3 axis is a novel and crucial signaling pathway that confers etoposide chemosensitivity. Therefore, TAp73? and IER3 induction would be a valuable checkpoint for successful therapeutic intervention of cervical carcinoma patients. PMID:25666857

Jin, Hanyong; Suh, Dae-Shik; Kim, Tae-Hyoung; Yeom, Ji-Hyun; Lee, Kangseok; Bae, Jeehyeon

2015-01-01

345

IER3 is a crucial mediator of TAp73?-induced apoptosis in cervical cancer and confers etoposide sensitivity.  

PubMed

Infection with high-risk human papillomaviruses (HPVs) causes cervical cancer. E6 oncoprotein, an HPV gene product, inactivates the major gatekeeper p53. In contrast, its isoform, TAp73?, has become increasingly important, as it is resistant to E6. However, the intracellular signaling mechanisms that account for TAp73? tumor suppressor activity in cervix are poorly understood. Here, we identified that IER3 is a novel target gene of TAp73?. In particular, TAp73? exclusively transactivated IER3 in cervical cancer cells, whereas p53 and TAp63 failed to do. IER3 efficiently induced apoptosis, and its knockdown promoted survival of HeLa cells. In addition, TAp73?-induced cell death, but not p53-induced cell death, was inhibited upon IER3 silencing. Moreover, etoposide, a DNA-damaging chemotherapeutics, upregulated TAp73? and IER3 in a c-Abl tyrosine kinase-dependent manner, and the etoposide chemosensitivity of HeLa cells was largely determined by TAp73?-induced IER3. Of interest, cervical carcinomas from patients express no observable levels of two proteins. Thus, our findings suggest that IER3 is a putative tumor suppressor in the cervix, and the c-Ab1/p73?/IER3 axis is a novel and crucial signaling pathway that confers etoposide chemosensitivity. Therefore, TAp73? and IER3 induction would be a valuable checkpoint for successful therapeutic intervention of cervical carcinoma patients. PMID:25666857

Jin, Hanyong; Suh, Dae-Shik; Kim, Tae-Hyoung; Yeom, Ji-Hyun; Lee, Kangseok; Bae, Jeehyeon

2015-01-01

346

TALEN-mediated targeting of HPV oncogenes ameliorates HPV-related cervical malignancy.  

PubMed

Persistent HPV infection is recognized as the main etiologic factor for cervical cancer. HPV expresses the oncoproteins E6 and E7, both of which play key roles in maintaining viral infection and promoting carcinogenesis. While siRNA-mediated targeting of E6 and E7 transcripts temporarily induces apoptosis in HPV-positive cells, it does not eliminate viral DNA within the host genome, which can harbor escape mutants. Here, we demonstrated that specifically targeting E6 and E7 within host DNA with transcription activator-like effector nucleases (TALENs) induces apoptosis, inhibits growth, and reduces tumorigenicity in HPV-positive cell lines. TALEN treatment efficiently disrupted E6 and E7 oncogenes, leading to the restoration of host tumor suppressors p53 and retinoblastoma 1 (RB1), which are targeted by E6 and E7, respectively. In the K14-HPV16 transgenic mouse model of HPV-driven neoplasms, direct cervical application of HPV16-E7-targeted TALENs effectively mutated the E7 oncogene, reduced viral DNA load, and restored RB1 function and downstream targets transcription factor E2F1 and cycling-dependent kinase 2 (CDK2), thereby reversing the malignant phenotype. Together, the results from our study suggest that TALENs have potential as a therapeutic strategy for HPV infection and related cervical malignancy. PMID:25500889

Hu, Zheng; Ding, Wencheng; Zhu, Da; Yu, Lan; Jiang, Xiaohui; Wang, Xiaoli; Zhang, Changlin; Wang, Liming; Ji, Teng; Liu, Dan; He, Dan; Xia, Xi; Zhu, Tao; Wei, Juncheng; Wu, Peng; Wang, Changyu; Xi, Ling; Gao, Qinglei; Chen, Gang; Liu, Rong; Li, Kezhen; Li, Shuang; Wang, Shixuan; Zhou, Jianfeng; Ma, Ding; Wang, Hui

2015-01-01

347

Sensitivity, Specificity, and Clinical Value of Human Papillomavirus (HPV) E6/E7 mRNA Assay as a Triage Test for Cervical Cytology and HPV DNA Test ?  

PubMed Central

There is evidence that testing for human papillomavirus (HPV) E6/E7 mRNA is more specific than testing for HPV DNA. A retrospective study was carried out to evaluate the performance of the PreTect HPV-Proofer E6/E7 mRNA assay (Norchip) as a triage test for cytology and HPV DNA testing. This study analyzed 1,201 women, 688 of whom had a colposcopy follow-up and 195 of whom had histology-confirmed high-grade intraepithelial neoplasia or worse (CIN2+). The proportion of positive results and the sensitivity and specificity for CIN2+ were determined for HPV mRNA in comparison to HPV DNA and cytology. All data were adjusted for follow-up completeness. Stratified by cytological grades, the HPV mRNA sensitivity was 83% (95% confidence interval [CI] = 63 to 94%) in ASC-US (atypical squamous cells of undetermined significance), 62% (95% CI = 47 to 75%) in L-SIL (low-grade squamous intraepithelial lesion), and 67% (95% CI = 57 to 76%) in H-SIL (high-grade squamous intraepithelial lesion). The corresponding figures were 99, 91, and 96%, respectively, for HPV DNA. The specificities were 82, 76, and 45%, respectively, for HPV mRNA and 29, 13, and 4%, respectively, for HPV DNA. Used as a triage test for ASC-US and L-SIL, mRNA reduced colposcopies by 79% (95% CI = 74 to 83%) and 69% (95% CI = 65 to 74%), respectively, while HPV DNA reduced colposcopies by 38% (95% CI = 32 to 44%) and by 15% (95% CI = 12 to 19%), respectively. As a HPV DNA positivity triage test, mRNA reduced colposcopies by 63% (95% CI = 60 to 66%), having 68% sensitivity (95% CI = 61 to 75%), whereas cytology at the ASC-US+ threshold reduced colposcopies by 23% (95% CI = 20 to 26%), showing 92% sensitivity (95% CI = 87 to 95%). In conclusion, PreTect HPV-Proofer mRNA can serve as a better triage test than HPV DNA to reduce colposcopy referral in both ASC-US and L-SIL. It is also more efficient than cytology for the triage of HPV DNA-positive women. Nevertheless, its low sensitivity demands a strict follow-up of HPV DNA positive-mRNA negative cases. PMID:21525231

Benevolo, Maria; Vocaturo, Amina; Caraceni, Donatella; French, Deborah; Rosini, Sandra; Zappacosta, Roberta; Terrenato, Irene; Ciccocioppo, Lucia; Frega, Antonio; Rossi, Paolo Giorgi

2011-01-01

348

HPV E6/E7 RNA In Situ Hybridization Signal Patterns as Biomarkers of Three-Tier Cervical Intraepithelial Neoplasia Grade  

PubMed Central

Cervical lesion grading is critical for effective patient management. A three-tier classification (cervical intraepithelial neoplasia [CIN] grade 1, 2 or 3) based on H&E slide review is widely used. However, for reasons of considerable inter-observer variation in CIN grade assignment and for want of a biomarker validating a three-fold stratification, CAP-ASCCP LAST consensus guidelines recommend a two-tier system: low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). In this study, high-risk HPV E6/E7 and p16 mRNA expression patterns in eighty-six CIN lesions were investigated by RNAscope chromogenic in situ hybridization (CISH). Specimens were also screened by immunohistochemistry for p16INK4a (clone E6H4), and by tyramide-based CISH for HPV DNA. HPV genotyping was performed by GP5+/6+ PCR combined with cycle-sequencing. Abundant high-risk HPV RNA CISH signals were detected in 26/32 (81.3%) CIN 1, 22/22 (100%) CIN 2 and in 32/32 (100%) CIN 3 lesions. CIN 1 staining patterns were typified (67.7% specimens) by abundant diffusely staining nuclei in the upper epithelial layers; CIN 2 lesions mostly (66.7%) showed a combination of superficial diffuse-stained nuclei and multiple dot-like nuclear and cytoplasmic signals throughout the epithelium; CIN 3 lesions were characterized (87.5%) by multiple dot-like nuclear and cytoplasmic signals throughout the epithelial thickness and absence/scarcity of diffusely staining nuclei (trend across CIN grades: P<0.0001). These data are consistent with productive phase HPV infections exemplifying CIN 1, transformative phase infections CIN 3, whereas CIN 2 shows both productive and transformative phase elements. Three-tier data correlation was not found for the other assays examined. The dual discernment of diffuse and/or dot-like signals together with the assay’s high sensitivity for HPV support the use of HPV E6/E7 RNA CISH as an adjunct test for deciding lesion grade when CIN 2 grading may be beneficial (e.g. among young women) or when ‘LSIL vs. HSIL’ assignment is equivocal. PMID:24625757

Evans, Mark F.; Peng, Zhihua; Clark, Kelli M.; Adamson, Christine S.-C.; Ma, Xiao-Jun; Wu, Xingyong; Wang, Hongwei; Luo, Yuling; Cooper, Kumarasen

2014-01-01

349

Pokemon (FBI-1) interacts with Smad4 to repress TGF-?-induced transcriptional responses.  

PubMed

Pokemon, an important proto-oncoprotein, is a transcriptional repressor that belongs to the POK (POZ and Krüppel) family. Smad4, a key component of TGF-? pathway, plays an essential role in TGF-?-induced transcriptional responses. In this study, we show that Pokemon can interact directly with Smad4 both in vitro and in vivo. Overexpression of Pokemon decreases TGF-?-induced transcriptional activities, whereas knockdown of Pokemon increases these activities. Interestingly, Pokemon does not affect activation of Smad2/3, formation of Smads complex, or DNA binding activity of Smad4. TGF-?1 treatment increases the interaction between Pokemon and Smad4, and also enhances the recruitment of Pokemon to Smad4-DNA complex. In addition, we also find that Pokemon recruits HDAC1 to Smad4 complex but decreases the interaction between Smad4 and p300/CBP. Taken together, all these data suggest that Pokemon is a new partner of Smad4 and plays a negative role in TGF-? pathway. PMID:25514493

Yang, Yutao; Cui, Jiajun; Xue, Feng; Zhang, Chuanfu; Mei, Zhu; Wang, Yue; Bi, Mingjun; Shan, Dapeng; Meredith, Alex; Li, Hui; Xu, Zhi-Qing David

2015-03-01

350

Ethoxysanguinarine Induces Inhibitory Effects and Downregulates CIP2A in Lung Cancer Cells  

PubMed Central

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncoprotein that is able to stabilize c-Myc oncogenic transcription factor and promote proliferation and transformation of cells. CIP2A is overexpressed in many primary tumors, and pharmacological inactivation of CIP2A is an emerging concept for the development of novel anticancer agents. In this study, we demonstrate that overexpression of CIP2A predicts poor prognosis in lung cancer, and a natural compound, ethoxysanguinarine (ESG), effectively downregulates CIP2A protein and its downstream signaling molecules, c-Myc and pAkt, and induces protein phosphatase 2A (PP2A) activity. ESG inhibits proliferation and induces apoptosis of lung cancer cells, and enhances the effects of cisplatin on malignant cells. Taken together, our findings demonstrate that CIP2A is inversely associated with the clinical outcome of lung cancer, and ESG can serve as a lead compound for the development of CIP2A inhibitor for cancer therapies. PMID:24900782

2013-01-01

351

HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway.  

PubMed

Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV). Although the interaction between HIV-1 and KSHV plays a pivotal role in promoting the aggressive manifestations of KS, the pathogenesis underlying AIDS-KS remains largely unknown. Here we examined HIV-1 Nef protein promotion of KSHV oncoprotein K1-induced angiogenesis. We showed that both internalized and ectopic expression of Nef in endothelial cells synergized with K1 to facilitate vascular tube formation and cell proliferation, and enhance angiogenesis in a chicken CAM model. In vivo experiments further indicated that Nef accelerated K1-induced angiogenesis and tumorigenesis in athymic nu/nu mice. Mechanistic studies revealed that Nef and K1 synergistically activated PI3K/AKT/mTOR signaling by downregulating PTEN. Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3' UTR of its mRNA. Inhibition of miR-718 expression increased PTEN synthesis and suppressed the synergistic effect of Nef- and K1-induced angiogenesis and tumorigenesis. These results indicate that, by targeting PTEN, miR-718 mediates Nef- and K1-induced angiogenesis via activation of AKT/mTOR signaling. Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target. PMID:25104021

Xue, Min; Yao, Shuihong; Hu, Minmin; Li, Wan; Hao, Tingting; Zhou, Feng; Zhu, Xiaofei; Lu, Hongmei; Qin, Di; Yan, Qin; Zhu, Jianzhong; Gao, Shou-Jiang; Lu, Chun

2014-09-01

352

HIV-1 Nef and KSHV oncogene K1 synergistically promote angiogenesis by inducing cellular miR-718 to regulate the PTEN/AKT/mTOR signaling pathway  

PubMed Central

Kaposi's sarcoma (KS) is an AIDS-defining cancer with aberrant neovascularization caused by KS-associated herpesvirus (KSHV). Although the interaction between HIV-1 and KSHV plays a pivotal role in promoting the aggressive manifestations of KS, the pathogenesis underlying AIDS-KS remains largely unknown. Here we examined HIV-1 Nef protein promotion of KSHV oncoprotein K1-induced angiogenesis. We showed that both internalized and ectopic expression of Nef in endothelial cells synergized with K1 to facilitate vascular tube formation and cell proliferation, and enhance angiogenesis in a chicken CAM model. In vivo experiments further indicated that Nef accelerated K1-induced angiogenesis and tumorigenesis in athymic nu/nu mice. Mechanistic studies revealed that Nef and K1 synergistically activated PI3K/AKT/mTOR signaling by downregulating PTEN. Furthermore, Nef and K1 induced cellular miR-718, which inhibited PTEN expression by directly targeting a seed sequence in the 3? UTR of its mRNA. Inhibition of miR-718 expression increased PTEN synthesis and suppressed the synergistic effect of Nef- and K1-induced angiogenesis and tumorigenesis. These results indicate that, by targeting PTEN, miR-718 mediates Nef- and K1-induced angiogenesis via activation of AKT/mTOR signaling. Our results demonstrate an essential role of miR-718/AKT/mTOR axis in AIDS-KS and thus may represent an attractive therapeutic target. PMID:25104021

Xue, Min; Yao, Shuihong; Hu, Minmin; Li, Wan; Hao, Tingting; Zhou, Feng; Zhu, Xiaofei; Lu, Hongmei; Qin, Di; Yan, Qin; Zhu, Jianzhong; Gao, Shou-Jiang; Lu, Chun

2014-01-01

353

Oncogenic c-Myc and prothymosin-alpha protect hepatocellular carcinoma cells against sorafenib-induced apoptosis.  

PubMed

Prothymosin alpha (PTMA) is overexpressed in various human tumors, including hepatocellular carcinoma (HCC). The significance of PTMA overexpression and its underlying mechanism remain unclear. We show here that silencing PTMA sensitizes HCC cells to the kinase inhibitor sorafenib. In contrast, ectopic expression of PTMA induces cell resistance to the drug. While inhibitors targeting JNK, ERK or PI3K reduce PTMA expression, only ERK activation is suppressed by sorafenib. In addition, inhibition of ERK produces a dramatic decrease in both endogenous PTMA level and promoter activation. Ectopic expression of active MKK1/2 considerably induces PTMA expression. We also identify a sorafenib-responsive segment lying 1000-1500-bp upstream of the PTMA transcription start site and observe that it is controlled by c-Myc and ERK. Mutation in the PTMA promoter at the predicted c-Myc binding site and silencing of c-Myc both abrogate sorafenib's effect on PTMA transcription. We also find that silencing PTMA potentiates Bax translocation to mitochondria in response to sorafenib and this is associated with increased cytochrome c release from mitochondria and enhanced caspase-9 activation. These results indicate that PTMA is positively regulated by the oncoprotein c-Myc and protects HCC cells against sorafenib-induced cell death, thus identifying PTMA as a new target for chemotherapy against HCC. PMID:25451688

Lin, Yi-Te; Lu, Hsing-Pang; Chao, Chuck C-K

2015-01-01

354

The LIM-only protein FHL2 is a serum-inducible transcriptional coactivator of AP-1.  

PubMed

Proteins with LIM domains have been implicated in transcriptional regulation. The four and half LIM domain (FHL) group of LIM-only proteins is composed of five members, some of which have been shown to have intrinsic activation function. Here we show that FHL2 is the only member of the family whose expression is inducible upon serum stimulation in cultured cells. Induction of FHL2 is coordinated in time with the increased levels of two early-response products, the oncoproteins Fos and Jun. FHL2 associates with both Jun and Fos, in vitro and in vivo. The FHL2-Jun interaction requires the Ser-63-Ser-73 JNK phosphoacceptor sites in c-Jun, but not their phosphorylation. FHL2 powerfully stimulates Fos- and Jun-dependent transcription, thereby acting as an inducible coactivator of AP-1 function. Moreover, we show that intracellular localization of FHL2 is controlled by signaling events and a Crm1-dependent active nuclear export mechanism. Thus, FHL2, as an inducible coactivator of AP-1, coordinately participates with Fos and Jun in the early transcriptional response to serum factors. PMID:12644711

Morlon, Aurore; Sassone-Corsi, Paolo

2003-04-01

355

CD4+CD25+ regulatory T cells that secrete TGFbeta and IL-10 are preferentially induced by a vaccine vector.  

PubMed

CD4CD25 T cells generated in a vaccine scenario can play a critical role in limiting antitumor therapy, thus having widespread implications for the immunotherapy-based treatment of cancer. The authors previously used Listeria monocytogenes to develop two vaccine constructs that express HPV-16 E7 protein and induce strong cellular immunity to HPV-E7-expressing tumors. Immunization of mice bearing established E7-expressing tumors with Lm-LLO-E7 induced regression of the tumors, whereas Lm-E7 showed little or no tumor regression. To investigate the possibility that regulatory CD4CD25 T-cell populations may be responsible for the differences in tumor regression, the authors characterized the role of these cells generated by the two vaccine systems. The authors compared the prevalence of CD4CD25 T cells in tumor-bearing vaccinated mice and demonstrate that Lm-E7-vaccinated mice have significantly increased numbers of CD4CD25 T cells in both the spleen and tumor-infiltrating lymphocytes compared with Lm-LLO-E7-vaccinated mice. The authors confirm that these increased numbers of CD4CD25 T cells are indeed suppressor in function by in vitro suppression assays and that the mechanism of action of the tumor-infiltrating cells involves the production of suppressor cytokines interleukin-10 and transforming growth factor beta. These results show that it is possible for a tumor vaccine system to generate tumor-infiltrating CD4CD25 regulatory T cells that critically affect tumor regression and the overall success of vaccine therapy. PMID:15314542

Hussain, S Farzana; Paterson, Yvonne

2004-01-01

356

Biosynthesis of the Cyanogenic Glucosides Linamarin and Lotaustralin in Cassava: Isolation, Biochemical Characterization, and Expression Pattern of CYP71E7, the Oxime-Metabolizing Cytochrome P450 Enzyme1[OA  

PubMed Central

Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A KS of approximately 0.9 ?m was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min?1 for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex cell layer. In fully unfolded leaves, the expression is pronounced in the cortex cell layer just beside the epidermis and in specific cells in the vascular tissue cortex cells. Thus, the transcripts of the CYP71E7 paralogs colocalize with CYP79D1 and CYP79D2. We conclude that CYP71E7 is the oxime-metabolizing enzyme in cyanogenic glucoside biosynthesis in cassava. PMID:21045121

Jørgensen, Kirsten; Morant, Anne Vinther; Morant, Marc; Jensen, Niels Bjerg; Olsen, Carl Erik; Kannangara, Rubini; Motawia, Mohammed Saddik; Møller, Birger Lindberg; Bak, Søren

2011-01-01

357

An Alternatively Spliced IL-15 Isoform Modulates Abrasion-Induced Keratinocyte Activation.  

PubMed

In a routine phenotype-driven screen, we identified a point mutation in exon 7 of the IL-15 gene in Pedigree 191 (deficient memory (DM)) of N-ethyl-N-nitrosourea mutagenized mice. The DM epidermis expressed an alternatively spliced IL-15 mRNA isoform, IL-15?E7, and a wild-type (WT) IL-15 isoform at comparable levels. Mechanical stimulation of DM skin or DM skin graft transplanted onto the WT host resulted in reduced keratinocyte activation and inhibition of neutrophil infiltration into the dermis, demonstrating that DM keratinocytes produced less inflammatory response to external stimulation. Ectopic expression of IL-15?E7 in WT skin prevented abrasion-induced epidermal thickening, blocked the accumulation of nuclear antigen Ki67(+) cells in the basal and the suprabasal cell layers, increased loricrin expression, and also increased keratinocyte CXCL1 and G-CSF production. IL-15?E7 also profoundly blocked neutrophil infiltration in SDS- or immiquimod (IMQ)-treated WT skin. Recombinant IL-15?E7 failed to activate STAT-5 and its downstream target bcl-2 expression. Our study points to IL-15?E7 as a potential therapeutic agent for treating neutrophilia-associated inflammatory skin disorders. PMID:25615554

Lee, Tsung-Lin; Chang, Mei-Ling; Lin, Yu-Jei; Tsai, Ming-Hsun; Chang, Yi-Hsuan; Chuang, Che-Ming; Chien, Yun; Sosinowski, Tomasz; Wang, Chih-Hsiu; Chen, Yi-Yuan; Lee, Chien-Kuo; Chen, Jau-Shiuh; Wang, Li-Fang; Kung, John T; Ku, Chia-Chi

2015-05-01

358

Upregulation of equine matrix metalloproteinase 1 by bovine papillomavirus type 1 is through the transcription factor activator protein-1.  

PubMed

Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by extensive invasion and infiltration of lymphatics, rare regression and high recurrence after surgical intervention. Bovine papillomavirus type 1 (BPV-1) activity is necessary for the transformation phenotype of equine fibroblasts. Among the many changes induced by BPV-1, matrix metalloproteinase 1 (MMP-1) upregulation contributes to the invasiveness of equine fibroblasts. However, it is not yet known how BPV-1 proteins regulate equine MMP-1 expression. To elucidate this mechanism, the equine MMP-1 promoter was cloned and analysed. A putative activator protein-1 (AP-1)-binding site was demonstrated to be crucial for upregulated MMP-1 promoter activity by BPV-1. BPV-1 E6 and E7 proteins increased MMP-1 promoter activity, and inhibition of BPV-1 gene expression by small interfering RNA significantly reduced the promoter activity. c-Jun and Fra-1, two components of the AP-1 transcription factor complex, were overexpressed and activated by BPV-1 in equine fibroblasts. Finally, BPV-1 E5, E6 and E7 proteins increased MMP-1 mRNA and protein expression. In conclusion, the expression of MMP-1 can be enhanced by BPV-1 oncoproteins E6 and E7 through the AP-1 transcription factor and by E5 via an indirect mechanism. These findings shed light on the mechanism of BPV-1-mediated equine fibroblast infiltration and indicate that both BPV-1 oncoproteins and AP-1 could be potential targets for equine sarcoid therapy. PMID:21775582

Yuan, ZhengQiang; Gault, Elizabeth A; Campo, M Saveria; Nasir, Lubna

2011-11-01

359

Sequential cisplatin therapy and vaccination with HPV16 E6E7L2 fusion protein in saponin adjuvant GPI-0100 for the treatment of a model HPV16+ cancer.  

PubMed

Clinical studies suggest that responses to HPV16 E6E7L2 fusion protein (TA-CIN) vaccination alone are modest, and GPI-0100 is a well-tolerated, potent adjuvant. Here we sought to optimize both the immunogenicity of TA-CIN via formulation with GPI-0100 and treatment of HPV16+ cancer by vaccination after cisplatin chemotherapy. HPV16 neutralizing serum antibody titers, CD4+ T cell proliferative and E6/E7-specific CD8+ T cell responses were significantly enhanced when mice were vaccinated subcutaneously (s.c.) or intramuscularly (i.m.) with TA-CIN formulated with GPI-0100. Vaccination was tested for therapy of mice bearing syngeneic HPV16 E6/E7+ tumors (TC-1) either in the lung or subcutaneously. Mice treated with TA-CIN/GPI-0100 vaccination exhibited robust E7-specific CD8+ T cell responses, which were associated with reduced tumor burden in the lung, whereas mice receiving either component alone were similar to controls. Since vaccination alone was not sufficient for cure, mice bearing s.c. TC-1 tumor were first treated with two doses of cisplatin and then vaccinated. Vaccination with TA-CIN/GPI-0100 i.m. substantially retarded tumor growth and extended survival after cisplatin therapy. Injection of TA-CIN alone, but not GPI-0100, into the tumor (i.t.) was similarly efficacious after cisplatin therapy, but the mice eventually succumbed. However, tumor regression and extended remission was observed in 80% of the mice treated with cisplatin and then intra-tumoral TA-CIN/GPI-0100 vaccination. These mice also exhibited robust E7-specific CD8+ T cell and HPV16 neutralizing antibody responses. Thus formulation of TA-CIN with GPI-0100 and intra-tumoral delivery after cisplatin treatment elicits potent therapeutic responses in a murine model of HPV16+ cancer. PMID:25560237

Peng, Shiwen; Wang, Joshua W; Karanam, Balasubramanyam; Wang, Chenguang; Huh, Warner K; Alvarez, Ronald D; Pai, Sara I; Hung, Chien-fu; Wu, T-C; Roden, Richard B S

2015-01-01

360

Sequential Cisplatin Therapy and Vaccination with HPV16 E6E7L2 Fusion Protein in Saponin Adjuvant GPI-0100 for the Treatment of a Model HPV16+ Cancer  

PubMed Central

Clinical studies suggest that responses to HPV16 E6E7L2 fusion protein (TA-CIN) vaccination alone are modest, and GPI-0100 is a well-tolerated, potent adjuvant. Here we sought to optimize both the immunogenicity of TA-CIN via formulation with GPI-0100 and treatment of HPV16+ cancer by vaccination after cisplatin chemotherapy. HPV16 neutralizing serum antibody titers, CD4+ T cell proliferative and E6/E7-specific CD8+ T cell responses were significantly enhanced when mice were vaccinated subcutaneously (s.c.) or intramuscularly (i.m.) with TA-CIN formulated with GPI-0100. Vaccination was tested for therapy of mice bearing syngeneic HPV16 E6/E7+ tumors (TC-1) either in the lung or subcutaneously. Mice treated with TA-CIN/GPI-0100 vaccination exhibited robust E7-specific CD8+ T cell responses, which were associated with reduced tumor burden in the lung, whereas mice receiving either component alone were similar to controls. Since vaccination alone was not sufficient for cure, mice bearing s.c. TC-1 tumor were first treated with two doses of cisplatin and then vaccinated. Vaccination with TA-CIN/GPI-0100 i.m. substantially retarded tumor growth and extended survival after cisplatin therapy. Injection of TA-CIN alone, but not GPI-0100, into the tumor (i.t.) was similarly efficacious after cisplatin therapy, but the mice eventually succumbed. However, tumor regression and extended remission was observed in 80% of the mice treated with cisplatin and then intra-tumoral TA-CIN/GPI-0100 vaccination. These mice also exhibited robust E7-specific CD8+ T cell and HPV16 neutralizing antibody responses. Thus formulation of TA-CIN with GPI-0100 and intra-tumoral delivery after cisplatin treatment elicits potent therapeutic responses in a murine model of HPV16+ cancer. PMID:25560237

Peng, Shiwen; Wang, Joshua W.; Karanam, Balasubramanyam; Wang, Chenguang; Huh, Warner K.; Alvarez, Ronald D.; Pai, Sara I.; Hung, Chien-fu; Wu, T. -C.; Roden, Richard B. S.

2015-01-01

361

Listeria-based vaccines can overcome tolerance by expanding low avidity CD8+ T cells capable of eradicating a solid tumor in a transgenic mouse model of cancer  

PubMed Central

We have created a transgenic mouse with tissue-specific expression of the human papilloma virus (HPV) 16 E6 and E7 oncoproteins in the thyroid as a model of HPV transformed cancer. The expression of the transgenes results in the formation of palpable thyroid tumors. E7 is not expressed in other tissues but is expressed in medullary thymic epithelial cells, which have been implicated in the control of negative selection. We show that Listeria-based vaccines against E7 can induce the regression of solid implanted tumors in the transgenic mice, although at a lower frequency than in wild type (WT) mice. E7-specific CD8+ T cells induced in transgenic mice are of both lower avidity and lower frequency when compared to the WT mice. In this model, Listeria-based vaccines against E7 appear to be overcoming central tolerance by expanding low avidity CD8+ T cells specific for E7 that are not deleted during thymopoesis and can eliminate solid tumors. PMID:17279610

Souders, Nicholas C.; Sewell, Duane A.; Pan, Zhen-Kun; Hussain, S. Farzana; Rodriguez, Alexander; Wallecha, Anu

2007-01-01

362

HPV E6/E7 mRNA Testing Is More Specific than Cytology in Post-Colposcopy Follow-Up of Women with Negative Cervical Biopsy  

PubMed Central

Background In Norway, women with negative or low-grade cervical biopsies (normal/CIN1) are followed up after six months in order to decide on further follow-up or recall for screening at three-year intervals. A high specificity and positive predictive value (PPV) of the triage test is important to avoid unnecessary diagnostic and therapeutic procedures whereas a low risk of high-grade disease among triage negative women assures safety. Materials and Methods At the University Hospital of North Norway, cytology and the HPV mRNA test PreTect HPV-Proofer, detecting E6/E7 mRNA from HPV types 16, 18, 31, 33 and 45, are used in post-colposcopy follow-up of women with negative or low-grade biopsy. In this study, women with negative biopsy after high grade cytology (ASC-H/HSIL) and/or positive HPV mRNA test in the period 2005–2009 were included (n?=?520). Histologically confirmed cervical intraepithelial neoplasia of grade 2 or worse (CIN2+) was used as study endpoint. Results Of 520 women with negative or low-grade biopsy, 124 women (23.8%) had CIN2+ in follow-up biopsy. The sensitivity and specificity of the HPV mRNA test were 89.1% (95% CI, 80.1–98.1) and 92.5% (95% CI, 88.2–96.7), respectively. The ratios of sensitivity, specificity and PPV of HPV mRNA testing compared to repeat cytology for finding CIN2+ was 1.05 (95% CI: 0.92–1.21), 1.21 (95% CI: 1.12–1.32), and 1.49 (95% CI: 1.20–1.86), respectively. The PPV of mRNA was 77.3% (95% CI, 59.8–94.8) in women aged 40 or older. Conclusion Women with negative cervical biopsy require follow-up before resumption of routine screening. Post-colposcopy HPV mRNA testing was as sensitive but more specific than post-colposcopy cytology. In addition, the HPV mRNA test showed higher PPV. A positive mRNA test post-colposcopy could justify treatment in women above 40 years. PMID:21998748

Sørbye, Sveinung Wergeland; Arbyn, Marc; Fismen, Silje; Gutteberg, Tore Jarl; Mortensen, Elin Synnøve

2011-01-01

363

Human Papillomavirus Type 8 Interferes with a Novel C/EBP?-Mediated Mechanism of Keratinocyte CCL20 Chemokine Expression and Langerhans Cell Migration  

PubMed Central

Infection with genus beta human papillomaviruses (HPV) is implicated in the development of non-melanoma skin cancer. This was first evidenced for HPV5 and 8 in patients with epidermodysplasia verruciformis (EV), a genetic skin disease. So far, it has been unknown how these viruses overcome cutaneous immune control allowing their persistence in lesional epidermis of these patients. Here we demonstrate that Langerhans cells, essential for skin immunosurveillance, are strongly reduced in HPV8-positive lesional epidermis from EV patients. Interestingly, the same lesions were largely devoid of the important Langerhans cells chemoattractant protein CCL20. Applying bioinformatic tools, chromatin immunoprecipitation assays and functional studies we identified the differentiation-associated transcription factor CCAAT/enhancer binding protein ? (C/EBP?) as a critical regulator of CCL20 gene expression in normal human keratinocytes. The physiological relevance of this finding is supported by our in vivo studies showing that the expression patterns of CCL20 and nuclear C/EBP? converge spatially in the most differentiated layers of human epidermis. Our analyses further identified C/EBP? as a novel target of the HPV8 E7 oncoprotein, which co-localizes with C/EBP? in the nucleus, co-precipitates with it and interferes with its binding to the CCL20 promoter in vivo. As a consequence, the HPV8 E7 but not E6 oncoprotein suppressed C/EBP?-inducible and constitutive CCL20 gene expression as well as Langerhans cell migration. In conclusion, our study unraveled a novel molecular mechanism central to cutaneous host defense. Interference of the HPV8 E7 oncoprotein with this regulatory pathway allows the virus to disrupt the immune barrier, a major prerequisite for its epithelial persistence and procarcinogenic activity. PMID:22911498

Walch-Rückheim, Barbara; Wickenhauser, Claudia; Doorbar, John; Pfister, Herbert; Malejczyk, Magdalena; Majewski, S?awomir; Keates, Andrew C.; Smola, Sigrun

2012-01-01

364

Human papillomavirus type 8 interferes with a novel C/EBP?-mediated mechanism of keratinocyte CCL20 chemokine expression and Langerhans cell migration.  

PubMed

Infection with genus beta human papillomaviruses (HPV) is implicated in the development of non-melanoma skin cancer. This was first evidenced for HPV5 and 8 in patients with epidermodysplasia verruciformis (EV), a genetic skin disease. So far, it has been unknown how these viruses overcome cutaneous immune control allowing their persistence in lesional epidermis of these patients. Here we demonstrate that Langerhans cells, essential for skin immunosurveillance, are strongly reduced in HPV8-positive lesional epidermis from EV patients. Interestingly, the same lesions were largely devoid of the important Langerhans cells chemoattractant protein CCL20. Applying bioinformatic tools, chromatin immunoprecipitation assays and functional studies we identified the differentiation-associated transcription factor CCAAT/enhancer binding protein ? (C/EBP?) as a critical regulator of CCL20 gene expression in normal human keratinocytes. The physiological relevance of this finding is supported by our in vivo studies showing that the expression patterns of CCL20 and nuclear C/EBP? converge spatially in the most differentiated layers of human epidermis. Our analyses further identified C/EBP? as a novel target of the HPV8 E7 oncoprotein, which co-localizes with C/EBP? in the nucleus, co-precipitates with it and interferes with its binding to the CCL20 promoter in vivo. As a consequence, the HPV8 E7 but not E6 oncoprotein suppressed C/EBP?-inducible and constitutive CCL20 gene expression as well as Langerhans cell migration. In conclusion, our study unraveled a novel molecular mechanism central to cutaneous host defense. Interference of the HPV8 E7 oncoprotein with this regulatory pathway allows the virus to disrupt the immune barrier, a major prerequisite for its epithelial persistence and procarcinogenic activity. PMID:22911498

Sperling, Tanya; O?dak, Monika; Walch-Rückheim, Barbara; Wickenhauser, Claudia; Doorbar, John; Pfister, Herbert; Malejczyk, Magdalena; Majewski, S?awomir; Keates, Andrew C; Smola, Sigrun

2012-01-01

365

Induced Abortion  

MedlinePLUS

What is induced abortion? An induced abortion is a procedure that is done to end a pregnancy. Most induced abortions are done in ... What are the risks of this type of abortion? Abortion is a low-risk procedure; however, on ...

366

Wip1 and p53 contribute to HTLV-1 Tax-induced tumorigenesis  

PubMed Central

Background Human T-cell Leukemia Virus type 1 (HTLV-1) infects 20 million individuals world-wide and causes Adult T-cell Leukemia/Lymphoma (ATLL), a highly aggressive T-cell cancer. ATLL is refractory to treatment with conventional chemotherapy and fewer than 10% of afflicted individuals survive more than 5 years after diagnosis. HTLV-1 encodes a viral oncoprotein, Tax, that functions in transforming virus-infected T-cells into leukemic cells. All ATLL cases are believed to have reduced p53 activity although only a minority of ATLLs have genetic mutations in their p53 gene. It has been suggested that p53 function is inactivated by the Tax protein. Results Using genetically altered mice, we report here that Tax expression does not achieve a functional equivalence of p53 inactivation as that seen with genetic mutation of p53 (i.e. a p53?/? genotype). Thus, we find statistically significant differences in tumorigenesis between Tax+p53+/+versus Tax+p53?/? mice. We also find a role contributed by the cellular Wip1 phosphatase protein in tumor formation in Tax transgenic mice. Notably, Tax+Wip1?/? mice show statistically significant reduced prevalence of tumorigenesis compared to Tax+Wip1+/+ counterparts. Conclusions Our findings provide new insights into contributions by p53 and Wip1 in the in vivo oncogenesis of Tax-induced tumors in mice. PMID:23256545

2012-01-01

367

Neoplastic Transformation of Human Small Airway Epithelial Cells Induced by Arsenic  

PubMed Central

Human small airway epithelial cells (SAECs) previously immortalized with human telomerase reverse transcriptase (h-TERT) were continuously treated with sodium arsenite at a dose of 0.5 ?g/mL in culture for up to 6 months. Arsenic-treated cells progressively displayed an increase in transformed phenotype including enhanced growth saturation density, plating efficiency, and anchorage-independent growth and invasion capability compared with their nontreated control cells. To determine whether arsenic-induced cell transformation was associated with genomic instability, treated and control cells were also analyzed for micronuclei formation. A 4.8-fold increase in micronuclei incidence in arsenic-treated cells was detected in conjunction with increased N-phosphonacetyl-l-aspartate (PALA)-resistant characteristics. In addition, arsenic-treated cells showed an increase in c-H-ras, c-myc, and c-fos protein expression relative to controls. The change in oncoprotein expression correlated with a decrease in wild-type p53 expression and hyperphosphorylated retinoblastoma. Taken together, these results strongly suggest that h-TERT immortalized human small airway epithelial cells underwent step-wise transformation after inorganic arsenic treatment. PMID:18037969

Wen, Gengyun; Calaf, Gloria M; Partridge, Michael A; Echiburú-Chau, Carlos; Zhao, Yongliang; Huang, Sarah; Chai, Yunfei; Li, Bingyan; Hu, Burong; Hei, Tom K

2008-01-01

368

Retroviral gene transfer of dominant negative raf-1 mutants suppresses ha-ras-induced transformation and delays tumor formation.  

PubMed

Activating mutants of ras are among the most frequently found genetic alterations in human cancers. Therefore, Ras appears to be an attractive target for therapeutic intervention using gene transfer. The protein kinase Raf-1 acts as a direct downstream effector of Ras and is involved in Ras-induced cellular transformation. Using the NIH3T3 fibroblast-derived tumor cell line PEJ, which expresses oncogenic Ha-rasG12V, we analyzed whether dominant negative mutants of Raf-1 can inhibit Ras-mediated transformation. Retroviral gene transfer was used to stably transduce PEJ cells with three different dominant negative mutants of Raf-1. This resulted in reversion of the transformed phenotype in vitro as evidenced by an increase in contact inhibition and reduced anchorage-independent growth. However, tumor formation in nude mice was significantly delayed only by one of these mutants. Therefore, dominant negative mutants of the oncoprotein Myc, which is known to synergize with Raf-1 in tumor formation, were transduced into PEJ cells expressing a dominant negative Raf mutant. This leads to killing of the cells. These results indicate that although interference with Ras-induced transformation using dominant negative mutants of Raf is feasible and effective in vitro using retroviral vectors, an additional block (e.g., that of Myc) is necessary to kill PEJ cells. These results also indicate that interference with Ras-dependent signaling is not sufficient for inhibition of tumor formation of PEJ cells in vivo. PMID:10830717

Heinicke, T; Radziwill, G; Nawrath, M; Rommel, C; Pavlovic, J; Moelling, K

2000-05-01

369

STAT5 is crucial to maintain leukemic stem cells in acute myelogenous leukemias induced by MOZ-TIF2.  

PubMed

MOZ-TIF2 is a leukemogenic fusion oncoprotein that confers self-renewal capability to hematopoietic progenitor cells and induces acute myelogenous leukemia (AML) with long latency in bone marrow transplantation assays. Here, we report that FLT3-ITD transforms hematopoietic cells in cooperation with MOZ-TIF2 in vitro and in vivo. Coexpression of FLT3-ITD confers growth factor independent survival/proliferation, shortens disease latency, and results in an increase in the number of leukemic stem cells (LSC). We show that STAT5, a major effector of aberrant FLT3-ITD signal transduction, is both necessary and sufficient for this cooperative effect. In addition, STAT5 signaling is essential for MOZ-TIF2-induced leukemic transformation itself. Lack of STAT5 in fetal liver cells caused rapid differentiation and loss of replating capacity of MOZ-TIF2-transduced cells enriched for LSCs. Furthermore, mice serially transplanted with Stat5(-/-) MOZ-TIF2 leukemic cells develop AML with longer disease latency and finally incomplete penetrance when compared with mice transplanted with Stat5(+/+) MOZ-TIF2 leukemic cells. These data suggest that STAT5AB is required for the self-renewal of LSCs and represents a combined signaling node of FLT3-ITD and MOZ-TIF2 driven leukemogenesis. Therefore, targeting aberrantly activated STAT5 or rewired downstream signaling pathways may be a promising therapeutic option. PMID:23149921

Tam, Winnie F; Hähnel, Patricia S; Schüler, Andrea; Lee, Benjamin H; Okabe, Rachel; Zhu, Nan; Pante, Saskia V; Raffel, Glen; Mercher, Thomas; Wernig, Gerlinde; Bockamp, Ernesto; Sasca, Daniel; Kreft, Andreas; Robinson, Gertraud W; Hennighausen, Lothar; Gilliland, D Gary; Kindler, Thomas

2013-01-01

370

Restoration of MAGI-1 Expression in Human Papillomavirus-Positive Tumor Cells Induces Cell Growth Arrest and Apoptosis  

PubMed Central

ABSTRACT The cancer-causing high-risk human papillomavirus (HPV) E6 oncoproteins target a number of cellular proteins that contain PDZ domains. However, the role of many of these interactions in either the HPV life cycle or in HPV-induced malignancy remains to be defined. Previous studies had shown that MAGI-1 was one of the most strongly bound PDZ domain-containing substrates of E6, and one consequence of this interaction appeared to facilitate the perturbation of tight junctions (TJs) by E6. In this study, we describe the generation of a mutation, K499E, within the MAGI-1 PDZ1 domain, which is resistant to E6 targeting. This mutant allows restoration of MAGI-1 expression in HPV-positive cells and defines additional activities of MAGI-1 that are overcome as a consequence of the association with E6. The reexpression of MAGI-1 in HPV-positive cells results in an increased recruitment of ZO-1 and PAR3 to sites of cell-cell contact, repression of cell proliferation, and induction of apoptosis. While the K499E mutation does not significantly affect these intrinsic activities of MAGI-1 in HPV-negative cells, its resistance to E6 targeting in an HPV-positive setting results in more cells expressing the mutant MAGI-1 than the wild-type MAGI-1, with a corresponding increase in TJ assembly, induction of apoptosis, and reduction in cell proliferation. These studies provide compelling evidence of a direct role for the perturbation of MAGI-1 function by E6 in the HPV life cycle and in HPV-induced malignancy. IMPORTANCE It is clear that the targeting of PDZ-containing substrates by E6 is important for the normal viral life cycle and for the progression to malignancy. Nevertheless, which of these PDZ domain-containing proteins is relevant for HPV pathology is still elusive. In a previous study, we provided evidence that MAGI-1 is a sensitive proteolytic substrate for both the HPV-16 and HPV-18 E6 oncoproteins; however, the biological consequences associated with loss of MAGI-1 expression in HPV-positive cervical cancer cells are still poorly understood. Using a mutant MAGI-1, resistant to E6-mediated degradation, we show that its expression in cervical cancer cells promotes membrane recruitment of the tight junction-associated proteins ZO-1 and PAR3, represses cell proliferation, and promotes apoptosis. These findings suggest that E6-mediated inhibition of MAGI-1 function contributes to HPV pathology by perturbing tight junction assembly with concomitant stimulation of proliferation and inhibition of apoptosis. PMID:24696483

Kranjec, Christian; Massimi, Paola

2014-01-01

371

Human papillomavirus type 16 variant analysis of E6, E7, and L1 genes and long control region in biopsy samples from cervical cancer patients in north India.  

PubMed

High-risk human papillomaviruses (HPVs), particularly HPV types 16 and 18 (HPV-16 and HPV-18, respectively), play a cardinal role in the etiology of cervical cancer. The most prevalent type, HPV-16, shows intratypic sequence variants that are known to differ in oncogenic potential and geographic distribution. This study was designed to analyze sequence variations in E6, E7, and L1 genes and the LCR (for long control region) of HPV-16 in cervical cancer patients to identify the most prevalent and novel HPV-16 variants and to correlate them with the severity of the disease. Cervical biopsies from 60 HPV-16-positive cancer cases were analyzed by PCR and DNA sequencing. The most frequently observed variations were T350G (100%) in E6, T789C (87.5%) in E7, A6695C (54.5%) in L1, and G7521A (91.1%) in the LCR. In addition, only one novel variant (T527A) in E6 and four new variants each in L1 (A6667C, A6691G, C6906T, and A6924C) and in the LCR (C13T, A7636C, C7678T, and G7799A) were identified. While E7 was found to be highly conserved, the variant 350G of E6 was the most prevalent in all of the histopathological grades. The majority of LCR variants were found at the YY1 transcription factor binding sites. Interestingly, a complete absence of the Asian lineage and a high prevalence of European lineages in E6, E7, L1, and the LCR (85, 86.7, 67.7, and 63.3%, respectively) indicate a possible epidemiological linkage between Europe and India with regard to the dissemination of HPV-16 infections in India. PMID:18199779

Pande, Shailja; Jain, Neeraj; Prusty, Bhupesh K; Bhambhani, Suresh; Gupta, Sanjay; Sharma, Rajyashri; Batra, Swaraj; Das, Bhudev C

2008-03-01

372

Deficiencies in the Fanconi Anemia DNA damage Response Pathway Increase Sensitivity to HPV-Associated Head and Neck Cancer  

PubMed Central

Patients with the rare genetic disease, Fanconi Anemia (FA), are highly susceptible to squamous cell carcinomas arising at multiple anatomical sites including the head and neck region. Human papillomaviruses (HPVs), particularly HPV16, are associated with ~20% of head and neck squamous cell carcinomas (HNSCCs) in the general population. Some but not other investigators have reported that HNSCCs in FA patients are much more frequently positive for HPV. In addition, studies have demonstrated an interaction between the HPV16 E7 oncoprotein and the FA pathway, a DNA damage response pathway deficient in FA patients. Based on these studies, it was hypothesized that the FA pathway contributes to repair of DNA damage induced by HPV16 E7, providing one explanation for why FA patients are predisposed to HPV-associated HNSCCs. To determine the importance of the FA pathway in modulating E7's oncogenic abilities, we crossed K14E7 transgenic (K14E7) and fancD2-knockout mice (FancD2?/?) to establish K14E7/FancD2?/? and K14E7/FancD2+/+ mice and monitored their susceptibility to HNSCC when treated with a chemical carcinogen. K14E7/FancD2?/? mice had a significantly higher incidence of HNSCC compared with K14E7/FancD2+/+ mice. This difference correlated with an increased proliferative index and the increase in expression of biomarkers that are used to assess levels of DNA damage. These animal studies support the hypotheses that FA patients have increased susceptibility to HPV-associated cancer and that the FA DNA damage response pathway normally attenuates the oncogenic potential of HPV16 E7. PMID:20935219

Park, Jung Wook; Pitot, Henry C.; Strati, Katerina; Spardy, Nicole; Duensing, Stefan; Grompe, Markus; Lambert, Paul F.

2010-01-01

373

A mechanistic study on the metastasis inducing function of FUS-CHOP fusion protein in liposarcoma.  

PubMed

The FUS-CHOP fusion protein has been found to be instrumental for specific oncogenic processes in liposarcoma, but its ability to induce metastasis and the underlying mechanisms by which this can be achieved remain unknown. To dissect its functional role in this context, we stably overexpressed this protein in SW872 liposarcoma and HT1080 fibrosarcoma cell lines, and were able to demonstrate that forced expression of FUS-CHOP significantly increases migration and invasion, as well as enhances lung and liver metastasis in the in vivo chicken chorioallantoic membrane (CAM) model, that is proliferation independent. Additionally, FUS-CHOP enhances the expression of matrix-metalloproteinases -2 and -9, and transactivates their promoters in vitro. Mutational analysis showed that C/EBP-?- (-769/-755), NF-?B (-525/-516) and CREB/AP-1 (-218/-207) sites were important for MMP-2 and NF-?B (-604/-598), AP-1 (-539/-532) and AP-1 (-81/-72) for MMP-9 transactivation. Moreover, a direct in vivo interaction of FUS-CHOP was observed in case of the MMP-2 promoter within region (-769/-207). siRNA data revealed that MMP-2 expression is essential in the FUS-CHOP induced metastatic phenotype. MMP-2-mRNA and protein expression correlated significantly with FUS-CHOP positivity in 46 resected patient liposarcoma tissues. We have for the first time provided substantial evidence for the FUS-CHOP oncoprotein as an inducer of metastasis that is due to the transcriptional induction of specific tumor-associated proteases. Insights gained from this study not only support a deeper understanding of the mechanistic properties of FUS-CHOP, but also open up new avenues for targeted therapy. PMID:24285420

Patil, Nitin; Ahmed Kabeer Rasheed, Suhail; Abba, Mohammed; Hendrik Leupold, Jörg; Schwarzbach, Matthias; Allgayer, Heike

2014-06-15

374

Induced pemphigus  

Microsoft Academic Search

The reports on induced pemphigus have multiplied over the last 10 years. Several heterogeneous factors, such as drugs (penicillamine, pyritinol, captopril, rifampicin, etc.), physical agents (burns, UV, and ionizing radiation) and viruses, can play an inducing role. Usually, the disease in preceded by prodromal, non-specific lesions. The full-blown stage shows features of pemphigus foliaceus, erythematosus or herpetiformis. Histologically, acantholytic splits

V. Ruocco; M. Pisani

1982-01-01

375

Cigarette smoke condensate-induced oxidative DNA damage and its removal in human cervical cancer cells.  

PubMed

Exposure to cigarette smoke is well documented to increase oxidative stress and could account for higher risk of cervical cancer in smokers. Cervical pre-cancerous lesions that are initiated by human papillomavirus (HPV) infection generally regress in the absence of known risk factors such as smoking. 8-oxodeoxyguanosine (8-oxodG) is a highly mutagenic oxidative DNA lesion that is formed by the oxidation of deoxyguanosine. In the present study, we examined: a) the effect of cigarette smoke condensate (CSC) on 8-oxodG formation in and its removal from HPV-transfected (ECT1/E6 E7), HPV-positive (CaSki) and HPV-negative (C33A) human cervical cancer cells, and b) the cell cycle progression and apoptosis in CSC-treated ECT1/E6 E7 cells. CSC induced 8-oxodG in a dose- (p=0.03) and time (p=0.002)-dependent fashion in ECT1/E6 E7 cells as determined by flow cytometry. A 2.4-fold higher level of 8-oxodG was observed in HPV-positive compared with HPV-negative cells. However, 8-oxodG lesions were almost completely removed 72 h post-exposure in all cell lines as determined by ImageStream analysis. This observation correlates with the 2- and 5-fold increase in the p53 levels in ECT1/E6 E7 and CaSki cells with no significant change in C33A cells. We conclude that: a) cigarette smoke constituents induce oxidative stress with higher burden in HPV-positive cervical cancer cells and b) the significant increase observed in p53 levels in wild-type cervical cells (ECT1/E6 E7 and CaSki) may be attributed to the p53-dependent DNA repair pathway while a p53-independent pathway in C33A cells cannot be ruled out. PMID:21720711

Moktar, Afsoon; Singh, Rajesh; Vadhanam, Manicka V; Ravoori, Srivani; Lillard, James W; Gairola, C Gary; Gupta, Ramesh C

2011-10-01

376

HPV16 E5 expression induces switching from FGFR2b to FGFR2c and epithelial-mesenchymal transition.  

PubMed

The E5 oncoprotein of the human papillomavirus type 16 (HPV16 E5) deregulates epithelial homeostasis through the modulation of receptor tyrosine kinases and their signaling. Accordingly, the fibroblast growth factor receptor 2b (FGFR2b/KGFR), epithelial splicing transcript variant of the FGFR2, is down-modulated by the viral protein expression, leading to impairment of keratinocyte differentiation. Here, we report that, in cell models of transfected human keratinocytes as well as in cervical epithelial cells containing episomal HPV16, the down-regulation of FGFR2b induced by 16E5 is associated with the aberrant expression of the mesenchymal FGFR2c isoform as a consequence of splicing switch: in fact, quantitative RT-PCR analysis showed that this molecular event is transcriptionally regulated by the epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) and is able to produce effects synergistic with those caused by TGF? treatment. Immunofluorescence analysis revealed that this altered FGFR2 splicing leads to changes in the specificity for the ligands FGFs and in the cellular response, triggering epithelial-mesenchymal transition (EMT). Through 16E5 or FGFR2 silencing as well as inhibition of FGFR2 activity we demonstrated the direct role of the viral protein in the receptor isoform switching and EMT, suggesting that these early molecular events during HPV infection might represent additional mechanisms driving cervical transformation and tumor progression. PMID:25450802

Ranieri, Danilo; Belleudi, Francesca; Magenta, Alessandra; Torrisi, Maria Rosaria

2015-07-01

377

Mutant N-Ras protects colorectal cancer cells from stress-induced apoptosis and contributes to cancer development and progression  

PubMed Central

N-Ras is one member of a family of oncoproteins that are commonly mutated in cancer. Activating mutations in N-Ras occur in a subset of colorectal cancers, but little in known about how the mutant protein contributes to onset and progression of the disease. Using genetically engineered mice, we find that mutant N-Ras strongly promotes tumorigenesis in the context of inflammation. The pro-tumorigenic nature of mutant N-Ras is related to its anti-apoptotic function, which is mediated by activation of a non-canonical MAPK pathway that signals through Stat3. As a result, inhibition of MEK selectively induces apoptosis in autochthonous colonic tumors expressing mutant N-Ras. The translational significance of this finding is highlighted by our observation that NRAS mutation correlates with a less favorable clinical outcome for colorectal cancer patients. These data demonstrate for the first time the important role that N-Ras plays in colorectal cancer.\\ PMID:23274911

Wang, Yufang; Velho, Sérgia; Vakiani, Efsevia; Peng, Shouyong; Bass, Adam J.; Chu, Gerald C.; Gierut, Jessica; Bugni, James M.; Der, Channing J.; Philips, Mark; Solit, David B.; Haigis, Kevin M.

2013-01-01

378

Human Papillomavirus 16 E5 Induces Bi-Nucleated Cell Formation By Cell-Cell Fusion  

PubMed Central

Summary Human Papillomaviruses (HPV) 16 is a DNA virus encoding three oncogenes – E5, E6, and E7. The E6 and E7 proteins have well-established roles as inhibitors of tumor suppression, but the contribution of E5 to malignant transformation is controversial. Using spontaneously immortalized human keratinocytes (HaCaT cells), we demonstrate that expression of HPV16 E5 is necessary and sufficient for the formation of bi-nucleated cells, a common characteristic of precancerous cervical lesions. Expression of E5 from non-carcinogenic HPV6b does not produce bi-nucleate cells. Video microscopy and biochemical analyses reveal that bi-nucleates arise through cell-cell fusion. Although most E5-induced bi-nucleates fail to propagate, co-expression of HPV16 E6/E7 enhances the proliferation of these cells. Expression of HPV16 E6/E7